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
2
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
3
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 Index, Sensory index
