UNIVERSITÀ DEGLI STUDI DI PISA
Wine quality evolution as a function of different storage conditions
Candidate: Dott. Xiaoguo Ying
Tutor:
Prof. Zinnai Angela Dr. Chiara Sanmartin
CONTENTS
1. Abstract 3
2. Introduction 5
2.1 Current situation of wine industry 5
2.2 Wine and Maturation 10
2.2.1 Main factors affecting the quality of wine 10
2.2.1.1 The influence of oxygen 11
2.2.1.2 The role played by Sulfur dioxide 13
2.2.1.3 Influence of temperature 15
2.2.1.4 The influence of Caps 16
2.3 Wine's package materials 18
2.3.1 Glass bottle 22
2.3.2 PET 23
2.3.3 Tetrabriks® 25
2.3.4 Bag in Box® (BIB) 26
Aim of the work 28
3. Materials and Methods 29
3.1 Wines 29 3.2 Experimental conditions 29 3.2.1 Topic 1 30 3.2.2 Topic 2 31 3.2.3 Topic 3 33 3.3 Chemical characterization 34 3.3.1 Total SO2 (TSO2) 35
3.3.2 Total Anthocyanins (TAnt). 35
3.3.3 Mathematical model. 36
3.4 Sensory analysis 37
3.5 Statistical analysis 38
4. Results and Discussion 39
4.1 Topic 1: 39
4.1.1 Chemical evolution of stored wine: 39
4.1.2 Sensorial evolution of stored wine: 41
4.2 Topic 1: Conclusions 43
4.3 Topic 2: 44
4.3.1 Chemical evolution of stored wine: 45
4.3.2 Sensorial evolution of stored wine. 46
4.3.3 Matrix of correlation 48
4.4 Topic 2: Conclusions 49
4.5 Topic 3: 49
4.5.1 Chemical evolution of wine 50
4.5.2 Sensorial evolution of stored wine 51
4.5.3 Matrix of correlation 52 4.6 Topic 3: Conclusions 52 5. References 54 Acknowledgments 62 Appendix 1 63 Appendix 2 68
1. Abstract
As the global wine market has been expanding from traditional area to new places, an increasing demand is expected in the coming years. The wine has a unique and complex nature compared with other fast moving consumption goods and there is a specific wine production cycle. Proper wine storage condition can be the key factor for the quality, nutritional value and health value. During the storage wine composition is continuously changed, depending critically on conditions like packaging, oxygen, and temperature. Glass containers are still usually preferred for bottling wine, being the only material with a high impermeability to gases and vapors, stability in time, transparency and readily recycled. Nevertheless, as a consequence of some objective limitations (i.e. heavy weight, fragility to internal pressure, impact and thermal shock, etc) for the extensive use of glass containers in food industry, nowadays there is growing worldwide demand for solutions alternative to glass also for bottling wine, in order to propose packaging resources inexpensive, practical to use and often marketed as “eco-friendly,” particularly in relation to their contributions to waste prevention. However, the measure of the environmental impact of packaging represents a huge problem of the modern industry and it appears relatively difficult to evaluate it, although several studies have carried out quantitative and qualitative assessments in this area.
In this context, among all the possible packaging materials, starting from the past two decades it was possible to observe an expansive utilization of polymeric materials for the packaging of wine, including PET bottles, multilayer tetrabrick and Bag in Box type containers.
During the wine storage high oxygen exposure of wine is known to be detrimental to the organoleptic quality, inducing changes of colour and aromatic profile. Most white wines are organoleptically evaluated for their characteristic fruity and fresh aromas, pale color, and acidic taste.
As the oxygen is one of the main factors affecting the wine evolution as well as its deterioration, the careful management of oxygen represent a critical issue during wine production and storage, so the packaging, being the barrier that protects the wine against the external behavior, play a fundamental role in the preservation of the whole quality of wine during all its life cycle, just starting from the bottling.
Obviously, the length of storage time is always important for the most of the wines, especially for the wines which have the aging potential, as well as the storage temperature,
which is a factor most important for different chemical reactions, having the change of temperature a power relationship with the reaction velocity.
Several research aimed at the compound changes during the wine ageing period have already been done; they focused on phenols and related phenol derivatives, amino acids, total acidity, etc. All these data are collected under accelerated storage conditions which simulate some of the changes of the prolonged aging but generally do not generate the desired subtle complexity of spontaneous storage.
Proper storage, at appropriate temperature, humidity, packaging, concentration of oxygen contributes during the aging to the wine quality thanks to the chemical reaction of phenolic compounds. Improper storage may change the color of wine, since rapid degradation of anthocyanin. It is worth promoting that the flavonoids are important anti-oxidation for wine, affecting the quality of the wine and more health functions.
Key words: Wine quality, Packaging Materials, Storage conditions, Physicochemical
2. Introduction
2.1 Current situation of wine industry
In history, wine cultivation, wine production, wine trade and wine consumption have evolved a lot. In the middle Ages, the wine was the privilege of the aristocrats, and later on, people from a wider range of classes began to have access to wine as well, as wine had become more affordable. Nowadays, wine plays an important role in global trades and markets. There are multiple factors that affect the process of wine production, trade, and consumption, including exterior factors and internal factors, ranging from natural conditions to regulations around the world in different markets, which have led to deep and significant changes in the global wine business. The past decades have seen the growth of international wine trade, profound geographical changes in production and consumption and export flow (Anderson and Nelgen, 2015; Anderson and Wittwer, 2016). During the last decade of the 20th Century, the wine industry grew mainly due to the fact that Northern Europe and North America saw more wine consumption during that decade, and the increase in those regions offset the decline in consumption in the Mediterranean countries. Another contribution was export growth, thanks to the so-called New World wine producers (Banks and Overton, 2010). Recently, the growth of international wine trade has been driven mainly by demand growth from Asia. Because of the rapid development of global economy, the Asian people really began to gradually contact and understand the wine culture. At the same time, certain importing countries also see an increase in wine production, such as China, India, and Brazil, which has considerable potential (Mariani and Pomarici et al., 2012). There is no doubt that the growth of global wine trade very well demonstrates the concept to see the wine industry as "an interesting example of globalization work" (Anderson, 2004). As a result of the growing importance of international wine trade, wine trade has become an indispensable part of global trade. Therefore, the study of wine is a topic of significance. According to Hugh Johnson, Pierre Sahni's book on global wine trade was introduced: "Can there be a more complex trade than commerce in wine? What other commodity is offered in such infinite variety, at prices from inconsiderable to fabulous? Its markets are as almost various as itself, ranging from regions where it is as every day as bread to milieus where it is elevated to a fashion item. However, due to the problems of laws and regulations in each country, the treatment of this problem is very complex and diverse.(Mariani and Pomarici et al., 2012). The development of global wine trade in the twentieth century is gratifying to the
liberalization process. There are multiple elements that have led to this process, including the establishment of economically integrated regions, where tariff and non-tariff barriers have been phased out, as well as WTO's gradual efforts in reducing duty tariffs and more effectively regulated non-tariff barriers(Anderson, 2010).
Since 2000, due to the rapid development of traditional logistics industry, resulting in a substantial increase in wine trade, so the original traditional structural model has undergone tremendous changes.These changes are the main competition direction for all traders in the global wine trade in the future.
In the 2000-2011 year period, the world's wine importsincreased substantially from 2004 to 2007, due to the international economic crisis, 2008-2009 years down, picked up in 2010. In 2011, the world's imports reached a new high: 3 million 400 thousand liters, to 2 billion 260 million euros. At the same time, as the growth of international trade is the result of the increase in consumption of no productive countries, world consumption has shown a moderate upward trend. Imports increased by 53% compared with 2000-2001 years, compared with the world average of 2010-2011 years, and the price has dropped by 58%. The International Organization of Wine (OIV) states that the biggest drop in wine production in 2014 hit key European producers, where drought against 2013 decreased production by about one sixth. It falls, as shown in the table below (Table 2.1) corresponds to a decrease of world wine production. In 2013 the Italian wine production reached 54 million hl, but the same year the French production was only 42.1 million hl. In the past, continuous trade data, we can clearly find that the Italy is now the largest producer in the world (as shown in Table 2.1). In the 2017 forecast, we can see a very large decline, mainly due to a serious cooling in Europe in April, resulting in the 20th century, the world's wine production reached the lowest in this century.
Table 2.1: Wine production 2013- 2017 (mil. hl)
Country 2013 2014 2015 2016 2017 Italy 54.0 44.2 50.0 50.9 39.3 France 42.1 46.5 47.0 45.2 36.7 Spain 45.3 39.5 37.7 39.3 33.5 United States 24.4 23.1 21.7 23.6 23.3 Australia 12.3 11.9 11.9 13.1 13.9 Argentina 15.0 15.2 13.4 9.4 11.8 China 11.8 11.6 11.5 11.4 11.4 South Africa 11.0 11.5 11.2 10.5 10.8 Chile 12.8 9.9 12.9 10.1 9.5 Germany 8.4 9.2 8.9 9.0 8.1 Portugal 6.2 6.2 7.0 6.0 6.6 Russia 5.3 4.9 5.6 5.6 5.6
Romania 5.1 3.7 3.6 3.3 5.3
Brazil 2.7 2.6 2.7 1.3 3.4
Hungary 2.6 2.4 2.8 2.8 2.9
Note: 2017 data are estimated and are likely to change in future reports. Source: OIV, October 2017
With the rapid development of Asia's economy in the past 20 years, more and more Asian people begin to understand wine, contact with wine, and enjoy the pleasant experience of wine.The Asian market, the third largest market after Europe and the United States, is becoming more and more popular among wine traders.
Table 2.2: The shift in consumption patterns
Year Europe America Asia Africa Pacific area
2010 69 20 6 3 2
2014 60 24 10 3 3
Variance -9 4 4 0 1
Source: The world market for wine-Retail News, OIV Statistical Report on World Vitiviniculture
In the last 20 years, PRC had a growth rate of GDP more than 8%, and this gave the possibility to climb the ranking of the World Economies, the aspect that more impresses is that China had the ability to increase for all this time his GDP despite the number of citizens. For all this period China was the first developing economies, and some data can give the idea of his growth, at the end of 70th all import and all export were the 9.7% of the GDP, one of the worst results in that period, in the following 20 years, these relation increase until to reach the 30%. For example, in 1997, the import and the export were 10 times more than in 1978, going from USD 20.6 to 325 billion. China has always maintained the world's second world economies, with a GDP of USD 11064.66 billion, basically the same of European Area with a GDP of USD 11602.40 billion. The most important market in Asia, for the wine, is China that in 2008 drank 1/3 of the whole continent. In China, from 2004 and 2008, we saw an increment of the consumption of wine of the 80%, and there are forecast that it will grow in the next future. To satisfy the huge demand, china will increment the imported wine but at the same time will increase the surface of the vineyard, trying to improve it the ranking position that we have seen before. China consumes more than 1/4 of luxury goods in the world, and it is the second consumer after the US, this growth is driven by the consumer from 20 to 40 years older, with an income from 5000 to 50000 Yuan per months. Some statistics calculate that the usual consumer in China are more than 10 million, and the potential market is from 5% to 10% of the population, from 60 to 130million. The westernization and the modernization are changing the style of the Chinese, and in the imminent future there are
a lot of chance for the wine, that is entering easily in the Chinese market in particular in some big city. Restaurant and wine bar are selling it with special promotion, just to promote it, and drink wine is becoming fashion. See below the fresh infographic on China’s main source of imported wines, and how big is their market share. The import figures back up recent research from Wine Intelligence that Chinese consumers are spending more on wine purchase and drinking more often. The free trade zones opened in several coastal cities in China are also bringing positive effects, according to the Ministry of Commerce of China. Tianjin free trade zone, the only free trade zone in Northern China, saw imports of alcoholic beverages increase by 86.5% in volume and 69.1% in value during the first six months of 2016. 90% of the total is wine and beer, officials said. There is a 28.5% jump in the average price of Italian wines.
Table 2.3: China bottled wine import figure 2016
Volume(litre) Value(USD) AVG Price(USD)
Rank by value Volume(litre) Year-on-year % Value(USD) Year-on-year % AVG Price Year-on-year % 1 France 84944781 15.95 503150270 36.36 5.92 17.6 2 Australia 35342784 40.93 278431319 32.52 7.88 -5.97 3 Chile 28593923 32.07 95415768 23.16 3.34 -6.74 4 Spain 36492915 45.28 74638985 41.51 2.05 -2.6 5 Italy 12792993 12.22 56998219 39.04 4.46 23.9 6 USA 5074304 -0.29 24726631 -9.78 4.87 -9.52 7 South Africa 3715809 -21.98 11755866 -44.22 3.16 -28.52 8 Argentina 2707437 8.24 11178331 19.28 4.13 10.2 9 New Zealand 1145804 27.24 11025974 13.72 9.62 -10.63 10 Portugal 3161877 20.21 9280142 25.11 2.94 4.07
Total of China wine imports
Bottled Wine 222753332 24.14 1109238975 29.49 4.98 4.31 Bulk wines 70664045 16.87 51344133 20.68 0.73 3.25 Sparkling wines 6374744 5.85 2656971 -10.19 4.17 -15.15 Total 299792121 21.91 1187144079 27.83 3.96 4.86
Also, China is still one of the most attractive markets in the world for wine imports. And now clearly the world's fourth largest destination for value. Interesting because the Chinese market is one of the few where one can see amazing opportunity to increase wine consumption and thus imports. 2016, descending into the details, it was characterized by the devaluation of the Yuan (CNY) of 6% on average, which has reduced a little growth in euro (+ 16%) compared to that in local currency (+ 24%). There was also a good year for Italy (such as Australia and Spain), + 33%, which does not, however, taken down from the second position in the market. 120 million exported wine for an import market of over
two billion continue to be a ridiculous number compared to the position occupied by the Italian product on the world stage. China is improving his rate of consumption, in fact statics calculate the number of usual drinker of wine, in China, is more than 10 million and that the potential market is the 10% of the whole population, and within 2020, the Wine market is expected to reach USD 7.8 million, and 1.7billion of liters. In the last years, normal and first-class wines were better performance, helped by rising income and constant effort by producer and distributor to spread wine. China is improving his rate of consumption, in fact statics calculate the number of usual drinker of wine, in China, is more than 10 million and that the potential market is the 10% of the whole population, and within 2020, the Wine market is expected to reach USD 7.8 million, and 1.7billion of liters. In the last years, normal and first-class wines were better performance, helped by rising income and constant effort by producer and distributor to spread wine.
According to a recent survey, “Made in Italy, of” 91% of the respondents answered that they a good perception of our product, nobody a bad perception. This result is a good base on which to build the brand image of the product. This result is given by the diligence of our country to build a good image of the “Made in Italy”. Also, the connection between the Italian wine and the image of that is positive, in fact, the 15% of the people affirmed that Italy is well known for the food and beverage. But the analysis, showed also that if the question is “What is the first Italian product that comes in your mind?” only 1.4% answered wine. This results shows that in China the people think that Italy is famous for the food, but that the wine is not yet seen as part of the Italian life style, that is given, maybe, by the poor penetration of the Italian wine in this market. As we saw before, China is improving a lot in the consumption of wine, in fact, the number of the consumer of wine is more than 10 million and that the potential market is around 5 and 10 % of the population, from 60 to 130 million of the customer. The westernization and the modernization are changing the Chinese behavior, and from some forecast, there is a good margin of improvement for the Italian wine.
2.2 Wine and Maturation
Like all other beverages, wine is affected by changes in composition due to its maturation related reactions. The term "Wine mature" includes a series of very complex biochemical phenomena, from the end of malolactic fermentation or sometimes alcohol fermentation end. The maturation phase of wine has a variable life: 90% of the wine is produced to be consumed within 12 months of packaging, 9% within 5 years, while only 1% is suitable for a longer aging. However, the aging process depends not only on the product characteristics, but also on other variables, such as storage temperature, oxidation reduction, sulfur dioxide and packaging system. The temperature, in fact, affects the speed of the reactions that take place in wine; Oxygen enters into many biochemists that can lead to an improvement or depreciation of the product; Sulfur dioxide is an additive with an antioxidant and antimicrobial function, which therefore allows longer durability. Finally, various packaging systems will also have a great change in the quality of the wine. The phenomena involved in the process have chemical, physical, biological and chemical physical properties. In the refining process, more or less have obvious changes in oxidation of phenolic compounds, acetalization reaction between alcohols and aldehydes, polyphenols and carbonyl compounds, the esterification between alcohol and acid, aldehyde, polysaccharide hydrolysis and formation of glucoside, polymerization of anthocyanins and catechins (Es-Safi and Cheynier et al., 2002; Silva Ferreira and Guedes De Pinho et al., 2002; Li and Guo et al., 2008). The major chemical and physical transformations involve the separation of salts, the release of gases, the evaporation of volatile substances, and the dissolution of many substances present in barrels (wines placed in gourds), and colloidal flocculation. At the same time, there may be biochemical transformations associated with the formation of acetic acid, autolysis of cells, and occasional microbial changes. Such a large number of Wine during ripening process may affect the assessment of the impact of the evolution of the variables to ensure that need good preservation, and provide the best sensory characteristics in a few months or years of bottled products to consumer.
2.2.1 Main factors affecting the quality of wine
Assuming that the quality of the starting wine is essential for preserving the product's longevity, it can be said that at least four other macro factors have a decisive effect on the wine itself over time. These factors are the amount of dissolved oxygen (during
production and after bottling), the concentration of sulfur dioxide, the temperature at each stage of the process, and the storage of the exposure time.
2.2.1.1 The influence of oxygen
In the wine, O2 is mainly responsible for this, it is reduced to some intermediates, and eventually become hydrogen peroxide and water. The molecule O2 exists as a free radical, so in a triplet state of the ground state. This limits the reaction of O2, which cannot form chemical bonds by accepting electron pairs. However, a single electron produced by the reduced transition metal ions can overcome this limitation. This leads to an unpaired electron in the resulting negative charge of the superoxide radical, and the second electron transfer leads to the peroxide anions (Miller and Buettner et al., 1990; Du Toit and Marais et al., 2017). This phenomenon led to O2 in the wine in a variety of reactions.
It is clear that phenolic molecules are the quantitative and qualitative components of wine, especially red wine. During the oxidation period, molecule O2 is reduced to 2H2O2 in a gradual manner, which requires four electrons to be added. This can be explained as follows:
O2 + e- , H+ → HO2 + e- , H+ → H2O2 + e- , H+ → OH (+H2O) + e- , H+ → (2) H2O. This results in the formation of free superoxide (O 2 -) and peroxide (O2 2-) free radicals. However, phenol and phenol are in the form of phenol or phenol salt. Electron transfer occurs in the phenol salt, leaving half a quinone free radical, which is further oxidized into the corresponding quinone. Therefore, quinones can be formed by the formation of phenol salts through molecules O2 or ion free O2 (molecules O2 and H2O2) or phenol. Because of the resonance stability of the adjacent and ionic electron of the aromatic ring, semi - quinone can further carry out free radical reaction (Singleton, 1987; Boulton and Singleton et al., 2013)
The process of oxidation in wine were summarized, and that phenol regeneration involves coupling oxidation process, the system to play the role of a "buffer" in the oxidation, because the regeneration of phenol easier than its corresponding phenols oxidation, thus preventing the initial complete oxidation of phenols (Singleton, 1987).
In the process of non-enzymatic oxidation of wine, the adjacent diphenol is oxidized to the o-quinone, which can produce half a quinone free radical, and the O2 is reduced to H2O2(Danilewicz, 2003; Waterhouse and Laurie, 2006) as shown in figure 2.1. Quinones that are formed as the main product are unstable and may react further. These may cause the reaction of pigments to be related to the enzymatic Browning, even with the enzyme
or non-enzymatic quinone (Singleton, 1987; Robards and Prenzler et al., 1999), such as condensation reaction forming a nonferrous product with a high molecular weight or reduction reaction to produce the original phenol class by trapping hydrogen atoms in other compounds (Figure 2.1).
Fig. 2.1 Non-enzymic oxidation reactions in wine.
Quinones with nucleophilic compounds (including phenol, thiol compounds and amine) spontaneously, because they have high electron affinity, and in the process, the dimers or polymers can change the rearrangement reaction to its structure through the enol to form new hydroquinone (Zhai and Du et al., 2001). For example, quinone - phenol dimer can be transformed into new diphenol dimer (Fig.2.1). In addition, the potential of the dimer or polymer produced is lower than the initial phenol, and is easy to oxidize (Boulton and Singleton et al., 2013). These regenerated adjacent diphenols can be reoxidized and eventually accelerated the polymerization of phenol (Zhai and Du et al., 2001; Boulton and Singleton et al., 2013). At the same time, in the presence of transition metal produce more of the H2O2, more ethanol was oxidized into aldehyde, and some initial is not easy to oxidation of phenol seems very easily by the above structural rearrangement oxidation (Zhai and Du et al., 2001; Boulton and Singleton et al., 2013). However, believes that catechin acid rearrangement may be some additives such as silica, boric acid and chloride and acetic acid zinc (II), and not as the pH value less than 8. Oxidation of phenol enzyme in alkaline condition happens very quickly, but in the acidic medium (such as normal pressure and temperature of wine) will be slower, especially if there is a metal ion (Oszmianski and Cheynier et al., 1996; Boulton and Singleton et al., 2013).
2.2.1.2 The role played by Sulfur dioxide
Sulfur dioxide (SO2), usually abbreviated to sulfite or sulfur dioxide, thanks to its antioxidant activity as well as antimicrobial properties, it can be called as the most important and widely used chemicals prevent wine from browning and oxidation. However, adding sulfur dioxide can cause health problems as opposed to personal serious allergic reactions caused by sensitive sulfite and sulfite concerns led to the organization WHO (World Health Organization) and O.I.V. (International Organization of Vine and Wine ) to develop regulatory restrictions set (Warner and Diachenko et al., 2000; Ribéreau-Gayon and Dubourdieu et al., 2006).
Due to the complex chemical balance of the molecule in wine, it is not easy to calculate the exact SO2 quantity. It exists in different forms in different compositions (Fig.2.2). It also exists in a compound with a different equilibrium constant, or a compound that does not contain the same as the active form. The combined SO2 is combined and measured with the free SO2 as the total SO2. In addition, the acid and base balance in wine must be considered as its form SO2, and the concentration of HSO3 - or SO42 – is directly dependent by the pH value (Santos and Nunes et al., 2012).
Fig. 2.2 Chemical equilibrium of SO2 when added as potassium metabisulphite (K2S2O5) in wine.
As we can see in Table 2.3, SO2 really plays an important role in wine, such as Prevent oxidation; Choice of yeast; and connect to consumer health.
Table 2.3 SO2 advantages and disadvantages.
Antioxidant
Inactivation of enzymes (Browning).
Oxygen scavenging. Reduces the quinones forms.
Inhibits Maillard reactions.
Depend by pH
(Oliveira and Ferreira et al., 2011; Santos and Nunes et al., 2012; Santos and Nunes et al., 2013)
Antimicrobial
“lactic disease” and “piqûre lactique”.
Prevents yeast haze formation
Prevent bioamines, ethyl phenol and odors from forming.
Depend by pH
(Suárez and Suárez-Lepe et al., 2007; Barata and Caldeira et al., 2008; Fleet, 2008; Santos and Nunes et al., 2013)
Sensory
The flavour of wine is more stable and complete The color will not change significantly.
Overuse can have unpleasant flavors and aromas
It causes hydrogen sulfide and mercaptan.
(Bakker and Bridle et al., 1998; Marsellés-Fontanet and Puig et al., 2009; Sonni and Cejudo Bastante et al., 2009)
Health
Allergic reactions in sensitive people: dermatitis, anaphylaxis, diarrhoea, abdominal pain, angioedema,
bronchoconstriction and urticaria.
(Fredericks and du Toit et al., 2011; Garaguso and Nardini, 2015; Campos and Couto et al., 2016)
As antioxidant, SO2 can act in three different ways: by direct oxygen scavenging; by reacting with hydrogen peroxide; and by reducing the quinones formed during the oxidation process back to their phenol form (Karbowiak and Gougeon et al., 2009; Oliveira and Ferreira et al., 2011).
In other papers, we can see clearly that in wine SO2 always make reactions with H2O2 to make antioxidant function, while restrict the oxidation process of the other saturated hydroxy compounds and ethanol (Bonilla and Mayen et al., 2001; Danilewicz, 2007).
2.2.1.3 Influence of temperature
When the reaction series and initial content of the research object are determined, the physical chemical stability of the object depends on the reaction rate constant k at room temperature. Temperature is one of the main factors affecting the quality factor of food quality.
Arrhenius's equation describes the relationship between the kinetic constant of a reaction and the temperature (Labuza, 1980):
k: kinetic constant;
A: Pre-exponential factor, constant for not too high temperature variations, whose value depends on the frequency of collisions and the steric factor;
Ea: activation energy, also constant for temperature variations not too high; R: gas constant 8.3144J/(mol·K);
T: absolute temperature.
Košmerl and Abramovič et al. analyzing 40 bottles of wine in different temperatures found that the influence of sample viscosity, with the increasing of temperature, viscosity and other characteristics and trend is nonlinear and the activation energy in the Arrhenius formula, so as to find the relationship between the osmotic concentration and viscosity (Košmerl and Abramovič et al., 2000).
Yanniotis and Kotseridis et al. measuring the viscosity of red and white wine and finding that the viscosity decreases with the increase of temperature can be fully described by the arrhenian equation. It was also found that alcohol and dry extract were the two main factors influencing the viscosity of wine (Yanniotis and Kotseridis et al., 2007).
Based on this equation, it can be assumed that, as the temperature rises, there is an increase in the rate of reactions occurring within the product. In the case of wine, this parameter assumes considerable importance, not only during fermentation, but also during storage, affecting the shelf life of the product.
Temperature, in addition to affecting the kinetics of degradative reactions, which is particularly important as oxidative, also influences the amount of dissolved oxygen within the wine. From the existing literature, it can be seen that improving storage temperature can accelerate the aging process of wine. The chemical characteristics of the wine can be
k
=
A
×
e
-Ea R×Tsignificantly changed with the increase of storage temperature, indicating that the reaction mechanism involved and Arrhenius activation energy are very sensitive to temperature. The temperature of the wine also affects the dissolved O2 saturation, and the lower concentration is dissolved at a higher temperature. At temperatures of 5 to 35 °C, the amount of O2 needed for the saturated wine fell from 10.5 mg/L to 5.6 mg/L. However, the formation rate of quinone increases with the increase of temperature (de Gaulejac and Vivas et al., 2001). Hopfer.et al. have shown that high temperature exposure is a particularly unfavorable condition during storage. By comparing the storage of a wine at three different temperatures (10 ° C, 20 ° C and 40 ° C), a good preservation of the product undergoes a lower temperature. Indeed, a decrease in titers and free and total sesame was recorded in the samples kept at 40 ° C, together with the disappearance of fruity and floral aromas, while there was an increase in the oxidation of caramel, vegetables cooked and molasses (Hopfer and Ebeler et al., 2012; Hopfer and Buffon et al., 2013).
2.2.1.4 The influence of Caps
Nowadays, glass containers are still preferred for bottling wine being them readily recyclable and characterized by a high impermeability to gases and vapours, stability over time and transparency (Silva and Lambri et al., 2003; Mentana and Pati et al., 2009). During storage the only barrier against the external atmosphere is represented by the closure system, and the evolution of phenolic compounds on the development of wine colour and mouthfeel mainly depends on the transfer of oxygen through the bottle stopper (Silva and Lambri et al., 2003; Gao and Tian et al., 2015). In this condition, oxygen diffusion into the bottled wine appears strongly dependent on the effective sealing of the closure. Indeed, oxygen permeability may greatly change from cork to cork, and this heterogeneity is one of the main factors affecting variation among bottles (Wirth and Morel-Salmi et al., 2010).
Since the invention of Dom Perignon in the 17th century, cork has been a traditional choice for wine bottles. Cork is the secondary plant tissue of the cork oak (Quercus suber). Its cellular material, cell tissue in a honeycomb structure is usually composed of a cell with a prism shape and a micropore, and its main function is to allow the tree to breathe. The polyhedral surfaces of cells are made of biosynthetic polymers such as lignin, su-lin, cellulose and hemicelluloses (Pereira, 2011).
On the other side, more and more surveys show that the unpleasant odor (2,4,6-trichloroanisole (TCA)) of «moldy cork taint» of wine is due to natural cork (Chatonnet and Labadie et al., 2003; Slabizki and Legrum et al., 2016; Zhao and Mou et al., 2016).
With the development of material technology and market natural demands, synthetic closures quickly becoming the new trend of 19th century wine market. Some studies have shown that synthetic closures are of good quality and have been tested extensively within established limits. Mechanical parameters, extraction and elastic returns prove that the closures should be in good condition during the storage period, at least 24 months after bottling. The use of this special type of closure made from expanded polyethylene helps to preserve the properties of wines consumed within 1 to 2 years after bottling (Wirth and Morel-Salmi et al., 2010). The screw cap, also known as roll-on-tamper-evident (ROTE), have been widely used in Australia and New Zealand wine market. The inner lining of the screw cap is usually made up of the 19µm PVDC membrane that comes in contact with the wine, as the 20µm layer of the gas barrier layer and the 2mm polyethylene foam used to keep the compression (Lopes, 2005).Usually, the benefits of screw cap can be found during aging of wine, keeping fresh flavor compounds. The Screw caps have been used in the wine market for the past 30 years, and according to market research, in the New Zealand market in 2005, we found that 70 percent of wines were made of Screw caps (Stelzer and Grosset et al., 2005). Godden and Francis et al. using different kind of caps: screw cap, natural cork and synthetic closures, as a parameter of experimental change. The closed performance evaluation of physical aspects such as extraction force and energy, changes in closed diameters and the ability to close reinsertions, and the composition and sensory properties of wine. The wine under the screw cap retains the maximum concentration of sulphur dioxide (SO2) and ascorbic acid, and has the lowest rate of brown change (Godden and Francis et al., 2001).
2.3 Wine's package materials
Due to the special nature of Wine packaging, so affected by the different directions (producers, retailers, and consumers) who have different priorities and do not always perceive the packaging as an added value to the product (Barlow and Morgan, 2013). The basic function of wine packaging materials is to protect the original quality of wine and avoid rapid degradation (primarily produced by environmental factors, such as oxygen, light and moisture), to ensure that consumers in the shelf life to better enjoy the original quality of wine (Marsh and Bugusu, 2007). At the same time wine packaging materials have been the use of some inert materials, because they can serve as a barrier to wine and other substances in the outside world, avoid other harmful substances into the wine (Limbo and Khaneghah, 2014).
Beverage packaging may delay product degradation, maintain the beneficial effects of processing, extend shelf life, and maintain or improve the quality and safety of food. Protective packaging provides three kinds of external influences: (1) physical protection, to prevent mechanical damage and include ease in the process of the allocation of shock and vibration; (2) microbial biological protection, to prevent attacks by microbial strains, insects or other animals; and (3) the chemical protection, to minimize the environmental impact caused, for example, by exposition to gas (usual oxygen), water (gain or loss) or light (Marsh and Bugusu, 2007). As consumers at affordable prices for higher quality products and increasing competition, not only in the composition of industrial manufacturing industry has undergone major changes but also changes in (Ramachandraiah and Han et al., 2015) processing and packaging system. With the progress and development of society, consumers pay more and more attention to food safety, health problems and environmental protection issues. Wine packaging industry due to the development of globalization, more and more attention to the impact of packaging materials on the quality of wine. Wine packaging materials, intelligent choice, need to consider the shelf life of the wine itself, the various countries of different laws and regulations and so on (Realini and Marcos, 2014).
Light transmission and oxygen permeability may be the cause of food deterioration and quality loss (Zygoura and Moyssiadi et al., 2004). In the traditional wine packaging materials, how to control the amount of oxygen is to determine the quality of wine an important condition. Because the necessary oxygen can promote the aging process of wine (Dombre and Rigou et al., 2015). Due to the different periods, will lead to changes in the color of the food itself in the color, and this change and consumer sensory
evaluation closely related (Wibowo and Grauwet et al., 2015). In the daily packaging of wine often use glass containers, mainly due to the nature of the glass itself is determined (Mentana and Pati et al., 2009). However, due to the rapid development of materials science, more and more people pay attention to the shortcomings and shortcomings of glass materials.In the relevant literature direction, there are a lot of research is to customer service which the shortcomings of glass material (Berlinet and Brat et al., 2008; Dombre and Rigou et al., 2015). More and more people because the weight of the plastic lighter than the more convenient as a new attempt,but it cannot be very good to protect the nature of the food itself, and there may be impact on consumer health problems (Pimentel and Madrona et al., 2015).
In the modern wine business, the main use of packaging materials are glass, plastic, Tetrabriks, Bag in Box and so on. The correct packaging material, to ensure that wine during storage can better preserve the characteristics of the wine itself, to ensure that consumers can have a better sensory enjoyment. We use the Table 2.4 more convenient to the advantages and disadvantages of which a variety of different materials show. However, there are also more cutting-edge research materials for different materials in the food and beverage packaging industry, mainly using some biodegradable materials to reduce the impact on the environment (Marsh and Bugusu, 2007; Pati and Mentana et al., 2010; Baiano and Mentana et al., 2015).
Table 2.4 Some advantages and disadvantages of typical materials used in wine packaging (Marsh and Bugusu, 2007).
Material Advantages Disadvantages
Glass Reusable and recyclable
Improved break resistance allows manufacturers to use thinner glass
Odorless and chemically inert Impermeable to gases and vapors
Maintenance of product freshness for a long period of time without impairing taste or flavor Useful for heat sterilization
Rigid
Good insulation
Production in numerous different shapes Variations in glass color can protect
light-Limitation in thin glass Heavy weight
Transportation costs Brittleness
Susceptibility to breakages from internal
pressure, impact, or thermal shock.
sensitive contents Transparent Plastic Fluid and moldable
Made into sheets, shapes, and structures Flexible
Chemically resistant Inexpensive
Light weight
Wide range of physical and optical properties Heat sealable
Easy to print
Integrated into production processes where the package is
formed, filled, and sealed in the same production line
Variable permeability to light, gases, vapors,
and low molecular weight molecules
Limited reuse and recycling properties
Tetrabriks® Lightweight
Economical compared to other packaging systems
Recyclable
Efficient, low cost protection Easy handling by consumers
Very good strength to weight characteristics
Poor barrier properties to light, moisture
Not used to protect wine for long periods of time When used as primary packaging, it is coated or laminated to improve functional and protective properties
The combination with other materials hinders the subsequent recycling process Tears easily
impact the organoleptic quality
Bag in Box® (BIB)
improved distribution efficiency
enhanced end-use convenience
increased cost-effectiveness
Easy handling by consumers
environmentally friendly
impact the organoleptic quality
sorb easily aroma compounds and particularly hydrophobic
incomplete air tightness of the valve
the composition of wine can also affect
Generally speaking, wine is a traditional drink which has a high nutritional value. Many epidemiological data certified that moderate wine drinking was very beneficial to human health. It can significantly reduce a variety of diseases, especially coronary heart disease, decrease mortality and prolong life (German and Walzem, 2000). The study confirmed that wine, especially red wine was rich in polyphenols. Polyphenols have strong antioxidant activity, and they can effectively remove particles ROS (Reactive oxygen species ROS), vasodilatory, anti-inflammatory, anti-viral, anti-heart disease, anti-cancer, etc (Giugliano, 2000; Lodovici and Guglielmi et al., 2001; Acquaviva and Russo et al., 2002; Ariga, 2004; Fernández-Pachón and Villano et al., 2004; Makris and Kallithraka et al., 2006). Due to a variety of beneficial nutrients effects of wine on human beings, more and more families drink wine. However, wine nutrients are highly susceptible to light, temperature, oxygen, microorganisms, and others (Recamales and Gallo et al., 2011; Dias and Smith et al., 2012; Du Toit and Marais et al., 2017). The occurrence of physical and chemical reactions and microbial damage (such as the propagation of bacteria) cause oxidative deterioration of wine, which will create adverse flavor, greatly reduce nutritional and sensory value. Browning is one of the chemical reactions happened in wine production and storage, and also it is an important long-standing issue. Since brewing materials contain grape tannins, oxidase, tyrosine, pigments, aldehydes and certain metal ions which are easily oxidized materials, the wine presents brown, wine turbidity, odor, and oxidation, resulting in browning. Browning is an oxidation process involving multiple components in wine (such as sugar, fat, amino acids and phenolic compounds), but also an important wine producing the longstanding problem. Browning not only seriously affects the taste and flavor of wine (Ferreira and Escudero et al., 1997; Escudero and Asensio et al., 2002; Silva Ferreira and Guedes De Pinho et al., 2002; Waterhouse and Laurie, 2006) , but also reduces the nutritional value of wine (Castellari and Matricardi et al., 2000; Bonilla and Mayen et al., 2001; Bassil and Makris et al., 2005; Sioumis and Kallithraka et al., 2005; Kallithraka and Tsoutsouras et al., 2006). If browning product goes into the body, it will cause harm to body health, and induce various diseases. While Browning also reduces the value of products, which will cause huge economic losses, so preventing browning of wine during wine storage and transportation is extremely important. Good storage conditions are the key factors to ensure high-quality wines. Reliable packaging technology for wine storage and transportation is essential. The main purpose of the package is to protect and retain, as far as possible, the original quality of beverages and foods. The most important physical and
chemical properties that make the packaging to realize its tasks are impermeability (light, carbon dioxide, oxygen etc.) (Robertson, 2016). Because of its inertness, on the migration of small molecular from the cover to the food and flavor scalping is also extremely important (Kontominas, 2010). In wine history, the glass bottle with the natural cork is more acceptable for the society, also someone connects traditional packaging with the elegant and high quality of life. With the economic and social development, more and more people recognize the importance of eco-packaging materials, so alternative packaging material more and more been made. Nowadays, with the development of technology wine package materials are as follows: Bag in Box, glass, plastic bottles, and so on (Belcher, 2006), which all influence the quality of shelf wine. In fact, some studies indicate that different packaging materials affected the physicochemical properties and sensory properties of wine (Fu and Lim et al., 2009; Mentana and Pati et al., 2009; Ghidossi and Poupot et al., 2012).
2.3.1 Glass bottle
The glass container is shaping from a specific type called soda-lime glass, composed of around 75% silicon dioxide (SiO2), calcium oxide (CaO), sodium oxide (Na2O), and several minor additives (Copley, 2001). So make glass bottle with a high impermeability to carbon dioxide (CO2), oxygen (O2), or even most of the liquid (Mentana and Pati et al., 2009). The glass bottle is the earliest packaging container used for wine and also continued for the longest time (McNulty, 1971; Meillon and Viala et al., 2010).
Ghidossi et al. (2012) studied the evolution of wine quality by different packaging materials (Glass, BIB, polyethylene terephthalate bottles). The samples were stored at 20 °C during 18 months. By analysis of white wine stored in different packaging configurations, they found glass bottles with more antioxidant capacity (Ghidossi and Poupot et al., 2012).
Glass bottle can be very good to prevent gas exchange inside and outside, to maintain the quality of the wine. Comparing white wine packaged in glass bottles with screw caps to polyethylene terephthalate (PET) bottles, Montana et al. showed that after the 7 months storage period (at 15−18 °C), the PET bottle was significantly different from the glass control in total and free SO2 content (lower), anthocyanin content (lower), degree of browning (higher), and sensory quality (lower), with significant changes in the volatile fraction due to the loss of phenyl ethanol, hexanoic, octanoic, and decanoic acid,
ethyl-2-hydroxy propanoate, and ethyl hydrogen succinate (Silva Ferreira and Guedes De Pinho et al., 2002).
Also, glass bottle wine is wine market’s common practice. Nowadays, glass container displays a wide range change in weight. In daily life, consumers have lots of options for wine. But before making a decision, they cannot drink the wine, only combine some extrinsic information. According to Piqueras-Fiszman and Spence (2012) consumers associate heavier glass bottles with high quality (Piqueras-Fiszman and Spence, 2012). As society develops, people are more concerned about the environment, people are more the need for a sustainable development of the industry. According to the development trend of the international wines，the wine bottle recycling is not a regionalized problem, but the problem of globalization. As the market tend to be more heavy bottles, so resulting in more carbon dioxide and waste more energy in production and transportation process. There is environmental pressure on the winemakers to decrease lots of glass bottles (WRAP, 2010). Moreover, in traditional way glass bottles always used natural cork as closure. Unfortunately, the nature cork will lead to trichloroanisole (TCA), an off-odor which will easily be smelled by normal people (Dombre and Rigou et al., 2015). With the development of modern logistics, the wine trade has become an international commercial behavior. However, due to the characteristics of glass bottle itself, the development speed of the wine trade is curbed. Firstly, the cost of the trade would be raised according to the weight of glass bottles. Secondly, the fragility of the glass could increase the difficulty of transportation. Thirdly, the thermal conductivity of the glass may change the quality of the wine during the ocean shipping process.
2.3.2 PET
Because of the raw materials (Polyethylene terephthalate (PET) combined with terephthalic acid and ethylene glycol), the advantages of PET bottles are multiple: economy, recoverable, light weight, transparency, and gas barrier properties (Ghidossi and Poupot et al., 2012). Because of these special properties, over the last 20 years, Polyethylene terephthalate (PET) is taken in an alternative to glass (Ghidossi and Poupot et al., 2012; Zygoura and Moyssiadi et al., 2004; Ros-Chumillas and Belissario et al., 2007).
Red Apulian table wines were studied by Mentana et al., (Mentana and Pati et al., 2009) where the authors looked at chemical changes due to different packaging (glass bottles and PET bottles with and without oxygen scavenger). Significant changes in enological
parameters, anthocyanin fraction, volatiles, and sensory properties were detected due to the different packages, with the largest changes in the normal PET bottles compared to the glass bottles. Flavor scalping (i.e., reduced amounts of various alcohols and ethyl esters) was observed to a higher extent in the normal PET bottle when compared to the PET bottle with oxygen scavengers. PET bottles with oxygen scavengers were more similar to the glass bottles, with no significant sensory differences between the two packaging types.
Annalisa Mentana et al. reported a study on the use of PET containers and glass containers for wine, after 6 months stored in the same condition, no significant variation in some chemical compound content was detected, while there was a trend for the organic ester compounds to be slightly lower in the PET contained wines (Mentana and Pati et al., 2009). Boidron et al. showed that quality of PET packed samples was much better than other packed ones (Boidron and Bar, 1988).
Clara Dombre et al. have compared aroma compounds and sensory parameters of wine packed in the traditional glass, virgin PET and 100% recycled PET bottles. It has appeared that the use of virgin PET and 100% recycled PET bottles detrimental to aromatic quality and sensory perception if long conservation is intended (Dombre and Rigou et al., 2015). Gabriella Giovanelli revealed that the most important changes happened in flavonoid and also in most anthocyanidins during all storage conditions, with greater degradation in PET bottles. L-Propanol originates from threonine and possesses a sweet taste (Revi and Badeka et al., 2014). Losses in L-propanol were higher (p < 0.05) in both plastic bags as compared to that in glass probably due to sorption of L-propanol by the polymer. Mentana et al.(Mentana and Pati et al., 2009) observed sorption of 2-phenyl ethanol by PET plastic containers. As various esters have been shown to be easily scalped by plastic films (Peyches-Bach and Dombre et al., 2012). It was also shown that the presence of ethanol facilitates the scalping process even more, particularly between 5% and 15%.
PET allows more oxygen ingress than glass, and thus the wine has a shorter shelf-life, losing freshness more quickly. Whether or not there are problems related to keeping wine in plastic is a controversial area. Plastics have an increasingly negative image in the eyes of consumers: convincing them that plastic is the environmentally friendly option will be difficult, and it will be hard to get away from the cheap ‘look’ that plastic bottles have.PET bottles are composed of single-layer and multilayer bottles, almost 85% of PET bottles in our daily lives are the multi-layer structure (De Beer and Harbertson et al., 2004).
2.3.3 Tetrabriks®
Tetrabriks® packaging is made up of three raw materials: duplex paper (about 75%), aluminum (about 5%) and low-density polyethylene (about 20%) (Korkmaz and Yanik et al., 2009). Tetrabriks® is a beverage and liquid food system widely used in over all the world as an aseptic packaging material. This remarkable packaging system allows products once considered perishable to be distributed and stored without refrigeration for periods up to six months or more – even for delicate foods such as milk, soy beverages, juice, and nectars. In 2007 more 137 billion Tetrabriks® packages were delivered in every corner of the world. Wine is traditionally glass bottled, but several wine makers have discovered the advantage of using Tetrabriks®. Carton packaging provides excellent protection for wine and keeps color and taste very convenient for consumers. The material reduces the weight and space of suppliers and consumers during transportation. Tetrabriks® also have significant weight advantages over conventional glass bottles. Tetrabriks® are mainly made of paper packaging materials, weight of about 40g, compared with glass bottles, the weight of 500g-750g.
In a more specific study, Blake et al.(Blake and Kotseridis et al., 2009) demonstrated the effect of wine packaging on the methoxy pyrazine concentrations in Riesling and Cabernet Franc wines and found that over a period of 18 months wines packaged in tetrabriks® or synthetic corks lost higher amounts of the methoxy pyrazines than natural cork or screw cap closures. The authors speculate that the observed changes among the different packaging types resulted from both differences in gas permeability and sorption phenomena. Wines stored in tetrabriks® were also the highest in red pigments and A420 nm and A520 nm values, most likely due to the higher oxygen ingress over time. Likewise, Blake et al. reported that Riesling wines in tetrabriks® containers had significantly higher (by 66%) A420 values, an indication of browning, compared to glass bottles after 18 months of storage at room temperature (Blake and Kotseridis et al., 2009). Blake et al. investigated the effect of closure and packaging type on impact odorants of Riesling and Cabernet Franc wines. After 12 months of storage, they reported no significant differences (p >0.05) in phenolics, titratable acidity, and pH between glass containers with different cork types and tetra pack type composite containers. Regarding free and bound SO2,tetrabriks® performed poorly resulting to twofold losses of SO2 as compared to glass containers after 12 months of storage at 20 C(Blake and Kotseridis et al., 2009).
2.3.4 Bag in Box® (BIB)
BIB packaging represents one of the most significant changes in the packaging of wine, offering improved distribution efficiency, enhanced end-use convenience, and increased cost-effectiveness. In this packaging system, the product is sealed in a bag comprising one or more plies of high-barrier flexible films, which are mechanically supported by an external paperboard carton. A valve fitment is attached to the bag through which the product is filled and dispensed (Petersen and Nielsen et al., 1999). With the BIB concept, wine is contained in a bag made of a high oxygen barrier multilayer flexible film inside a cardboard box. The film allows to prevent oxidation and to preserve organoleptic qualities of wine (colour and flavour) (An and Kim et al., 2001). However losses of ethanol and aroma compounds by sorption in the film or permeation through the bag can occur and impact the organoleptic quality. Indeed, BIB multilayer films are usually made of polyethylene film (PE) which is well known to sorb easily aroma compounds and particularly hydrophobic ones, which can results in changing the aromatic balance of wine (Conte and Gammariello et al., 2009; Del Nobile and Conte et al., 2009).
Furthermore, since Bag in Box® has emerged the wine industry has shown considerable interest in, and found numerous applications for, this technology. BIB consists of a resistant bladder (or plastic bag), usually comprising several layers in the same way as PET multi-layer bottles. For protection, the bag is housed in a sturdy cardboard box (Holm and Mortensen et al., 2006). The storage effects of BIBs on white Bordeaux wine properties were studied by Ghidossi et al. The direct contact with the Wine polyolefins (polyethylene, polypropylene) packaging materials is their main drawback of volatile flavor compounds strongly adsorbed to Wine, resulting in a large number of bad flavor products. Owing to the hydrophobic nature of polyolefins, the adsorption capacity of non-polar volatiles was higher (Sajilata and Savitha et al., 2007). Other factors affecting the adsorption capacity of volatiles include pH, storage temperature, the degree of interaction between volatiles and food ingredients, the glass transition temperature (Tg) of polymer materials as well as the incomplete tightness of the valve (Monthly, 2009; Dombre and Rigou et al., 2015). According to Hopfer et al. (Hopfer and Buffon et al., 2013) the difference of flavor characteristics between BIB and bottle processing is due to the existence of BIB in the samples during the storage of high oxygen or flavor from perm result, because of various esters have been shown to be plastic film absorption (Peyches-Bach and Dombre et al., 2012). It is also shown that the presence of ethanol contributes to the absorption process, especially between 5% and 15%. One of the potential defects
in BIB packaging is that the lining material is prone to rupture due to the formation of creases and lining materials during movement and handling of the fluid in the bag due to movement of the bag. The gasket regions located at the corners and edges of the box are particularly susceptible to the effects of flexural cracking defects that may impair the barrier properties of packaging (Doyon and Poulet et al., 1995). Changes in barrier properties in wine related repeat samples seem to indicate that these structural defects may exist in test samples.
Aim of the work
There are more than one million wine makers in the world, producing around 2.8bn cases of wine each year. Global demand has hit nearly 3bn and is rising. But the global wine industry is changing shape, with the old world gradually losing its crown as the world's vineyard, and new wine drinkers emerging from countries like China. . The wine has a unique and complex nature compared with other fast moving consumption goods and there is a specific wine production cycle. Proper wine storage condition can be the key factor for the preservation of the quality, nutritional value and health value. During the storage, wine composition is continuously changed, depending critically on conditions like packaging, oxygen intake, and storage temperature.
The main purpose of this research was to fully understand the effects of different storage conditions (packaging materials and volume, storage temperature, capsule and storage position) on the chemical and sensorial evolution of different kinds of wine (white and red) over 12 months of storage period, so as to optimize the storage conditions for wine to maintain its best quality.
The aim of the work was achieved through three different topics:
Topic 1: To evaluate the effects of packaging materials (glass bottles provided with different closures vs. BiB vs. Tetrabriks®), packaging volumes and storage temperature (4 and 20°C) on the chemical and sensorial evolution of a white table wine over a period of 12 months.
Topic 2: To determine the effects of packaging materials (glass bottles with crown cap vs. multilayer Tetrabriks®) and temperature levels (4 and 20°C) on the preserving quality of red wine (both chemical and sensorial evolution aspects) over a storage period of 12 months.
Topic 3: To identify the influence of capsule and storage position (horizontal vs vertical) on the chemical and sensorial evolution of a not structured red wine stored over a period of 12 months.
3. Materials and Methods
3.1 Wines
In Table 3.1 the chemical characteristics of all the wines utilized in different experimental runs are reported.
Table 3.1 Initial chemical composition of the different wines utilized for all the experimental runs.
Topic 1 Topic 2 Topic 3
Parameter White wine Mean value ± c. i.* Red wine Mean value ± c. i.* Red wine Mean value ± c. i.* Total SO2 (g/L) 0.117±0.008 0.100±0.007 0.111±0.003 pH 3.35 ± 0.01 3.62±0.01 3.41±0.01 alcohol (% v/v) 12.00±0.01 12.50±0.01 11.46±0.06 Titratable Acidity (g/L as tartaric acid) 4.96 ± 0.02 4.82±0.20 5.32±0.01
Net Volatile Acidity
(g/L as acetic acid) 0.30 ± 0.02 0.55±0.02 0.40±0.01 Total Phenols (g/L as catechins) 1.24 ± 0.03 3.85±0.07 3.40±0.02 Proanthocyanidins (g/L as catechins) 0.05±0.01 1.10±0.01 1.34±0.03 Total Anthocyanins (g/L as malvin) -- 0.470±0.006 0.310±0.002
*c.i. = confidence interval, α < 0.05.
3.2 Experimental conditions
During the PhD period different experimental conditions were adopted to investigate the time evolution of stored wine as a function of:
Topic 1: To evaluate the effects of packaging materials (glass bottles provided with different closures vs. BiB vs. Tetrabriks®), packaging volumes and storage temperature
(4 and 20°C) on the chemical and sensorial evolution of a white table wine over a period of 12 months.
Topic 2: To determine the effects of packaging materials (glass bottles with crown cap vs. multilayer Tetrabriks®) and temperature levels (4 and 20°C) on the preserving quality of red wine (both chemical and sensorial evolution aspects) over a storage period of 12 months.
Topic 3: To identify the influence of capsule and storage position (horizontal vs vertical) on the chemical and sensorial evolution of a not structured red wine stored over a period of 12 months.
3.2.1 Topic 1
In Figure 3.1 are reported the experimental conditions related to the research topic 1.
Figure 3.1. Experimental protocol of topic 1: a white table wine was stored in different packaging materials (glass bottles provided with different closures; bag-in-box (BiB) containers; tetrabriks®) and different volumes (2 volumes for each packaging) and its evolution has been evaluated over a period of 12 months. For each packaging solution two different temperature levels (4° and 20°C) were also maintained throughout the storage period.
The white table wine (TOPIC 1) was packed in different packaging materials at the same time in a commercial winery bottling line, using a fully automated bottling/filling station as reported below:
– Glass bottles (different volumes) + different closures:
Crown cap (0.5 and 1 L)
Screw cap (0.375 and 0.750 L)
Cork (0.375 and 0.750 L)
Polymeric (0.375 and 0.750 L) – Tetrabrik® (0.250 and 1 L)
– BiB (3 and 20 L)
For each packaging, container volumes were chosen based on the most frequent use specific for each of them. In order to reduce the bias deriving from the utilisation of different volumes for different packaging, the volume effect was studied by comparing each other the values obtained for each couple (large volume vs small volume) of packaging solution. Packaged wine was shipped by air-conditioned truck (T = 20 ± 1°C) from the bottling/filling facility located at Castellina Marittima (PI) to the Food Technology Laboratory of the DAFE (University of Pisa) after 1 day from bottling/packaging. During the whole observation period all samples were stored in a controlled temperature cabinet at two different temperature levels: 4 ± 1°C and 20 ± 1°C. As glass is characterized by a high impermeability to gases and vapours (Mentana et al., 2009), when wine is stored in a glass bottle, the barrier against the external atmosphere is provided by the closure. In order to highlight the real influence of the different closures on the evolution of the stored wine, all bottles were maintained without the capsules throughout the storage time. Sampling of wine was carried out at 3 days, 6 months and 12 months of storage. Samples where stored under inert atmosphere (N2) and immediately analysed, while a future aliquot of each was immediately stocked.
3.2.2 Topic 2
Figure 3.2. Experimental protocol of topic 2: a red table wine was stored in two different packaging materials (glass bottles provided with crown cap and tetrabriks®) with two different volumes for each packaging; its evolution has been evaluated over a period of 12 months and for each packaging solution two different temperature levels (4° and 20°C) were also maintained throughout the storage period.
The red table wine was packed in different packaging materials (glass bottles, V=1L; Tetrabrik®, V=1L) at the same time in a commercial winery bottling line using a fully automated bottling/filling station. Packed wine was shipped by air-conditioned truck (T=20±1 °C) from the bottling/filling facility located at Castellina Marittima (PI) to the Food Technology Laboratory of the DAFE(University of Pisa) 1 day after bottling/packaging. During the whole observation period, all samples were stored in a controlled temperature cabinet at two different temperature levels: 4±1 °C and 20±1 °C. Sampling of wine was carried out at 3 days, 6 months and 12 months of storage. Samples where stored under inert atmosphere (N2) and immediately analysed, while a future aliquot of each was immediately stocked.
3.2.3 Topic 3
In Figure 3.3 are reported the experimental conditions related to the research topic 3.
Figure 3.3. Experimental protocol for topic 3: a red wine stored over a period of 12 months in glass bottles closed with natural cork stoppers with or without capsule and maintained in different storage position (horizontal vs vertical).
The red wine, collected from one single vat, was stored in glass bottles (0.750 L) at the same time in a commercial winery bottling line using a fully automated bottling/filling station. After the washing process, the bottles passed automatically to the filling machine and then to the corking. In order to eliminate the presence of oxygen in the bottles, before capping the air in the headspace was replaced with an inert gas. In particular, we used Nitrogen (N2), the chemical inertia of which makes it particularly suitable in fields where the high reactivity of oxygen causes unwanted actions. All the bottles were closed with the same natural cork stopper. This100% natural product was extracted from a single cork strip and was perfected using the cutting-edge technology. As reported in Fig. 3.1, the bottles were divided equally in two groups: one group was closed with a natural cork (one-piece cylindrical cork stoppers of natural origin deriving from the bark of the cork-oak tree (Quercus suber) by punching) and aluminium capsule, while the other was closed with cork but without the capsule.
Bottles were transported by an air-conditioned truck(T= 20 ± 1 °C) from the bottling/filling facility located at Ruvo di Puglia (BA) to the Food Technology Laboratory of the Department of Agriculture, Food and Environment (DAFE) of the University of Pisa after one day from bottling/packaging. Each group was further divided in order to verify the influence of the storage position (vertical vs horizontal) on the time evolution of wine. Sampling and analyses were performed at the DAFE. Sampling of wine was carried out after 3 days and 3, 6, 9 and 12 months of storage. Throughout the observation period samples were stored under controlled temperature (T= 20 ± 1 °C). Samples where stored under inert atmosphere (N2) and immediately analysed, while a future aliquot of each was immediately stocked.
3.3 Chemical characterization
All chemical determinations for the characterization of the starting wine (Table 3.2) were performed at the laboratory of Food Technology of DAFE according to the official methods proposed by the International Organization of Vine and Wine (OIV), and described in the Compendium of International Methods of Wine and Must Analysis (OIV, 2014): OIV-MA-AS313-15 (pH);OIV-MA-As313-01 (Total acidity); OIV-MA-AS312-01A (Alcoholic strength by volume);OIV-MA-AS313-01 (Net volatile acidity). The determination of the main phenolic compounds was run according to the official methods proposed by AMERINE and OUGH (1988). The methods utilized for the determination of total sulphur dioxide content (TSO2) and Total Anthocyanin content (TAnt) during wine storage are described in detail below.
Table 3.2. Chemical determinations for the characterization of the starting wine performed during the composition of the different wines utilized for all the experimental runs.
Experimental method Reference
Total SO2
(g/L) (Zoecklein, Fugelsang, Gump & Nuri, 1999).
pH OIV-MA-AS313-15
alcohol
(% v/v) OIV-MA-AS312-01A
Titratable Acidity
(g/L as tartaric acid) OIV-MA-As313-01
Net Volatile Acidity
(g/L as acetic acid) OIV-MA-AS313-01
