TORRES Myriam Mariela
congresos y reuniones científicas
Effect of New Packaging Material, Oxygen and Light Transmission, and Storage Time on Quality Characteristics of Extra Virgin Olive Oil
San Juan
Simposio; VII International Symposium on Olive Growing; 2012
In recent years, many new food packaging concepts have been introduced. Consumers are increasingly demanding mildly preserved convenience foods that have better fresh-like qualities. In addition, changes in retail and distribution practices such as centralization of activities, new trends (e.g. internet ?shopping) and internationalization of markets, resulting in increased distribution distances and longer storage times are putting huge demands on the food packaging industry. This present study was undertaken with the principal objective to analyze the effect of new flexible packaging properties (medium and high barrier), up to now not present on vegetable oil industry, namely: oxygen permeability, light transmission and head-space volume on olive oil quality (OOQ) under realistic storage conditions. A second objective was to determinate the relative contribution of each of the above parameters to OOQ. Extra-virgin olive oils (EVOO) samples were elaborated with high, medium and low total phenols content (325, 255 and 136 ppm, respectively). All of them had the same fatty acids composition. Quality parameters monitored over storage time included: free acidity, peroxide value, absorption coefficients (K232 and K270), chlorophyll and carotenoid compounds and total phenol contents. Two sets of packaged oils were prepared and placed inside a thermostated chamber at 25 ± 1 ºC: one set was stored under illumination (1100 Lux) and the other was kept in the darkness. Each treatment (consisting of a combination from EVOO sample / package type / illumination condition) was prepared in duplicate. Oils were stored for six months. Each individual oil sample was removed from the chamber once every three months and used to measure the chemical parameters as indicated previously. Overall there were no statistically significant differences (SSD) between the both types of packaging and storage conditions (light vs. dark). However, SSD were recorded among types of EVOO considered. Oils with lower initial total phenols content tended to exhibit higher acidity values, although these did not exceed the maximum allowed by the IOOC for the highest quality category during the first six months evaluated (<0.8% oleic acid). In addition, these showed a greater loss of total phenolic compounds over time. Oils with higher initial values of total phenols showed an opposite trend with respect to the free acidity parameter, while maintaining stable values of the antioxidant and pigments. In turn, olive oils with intermediate initial total phenol showed a qualitative intermediate behavior to the above oils. Moreover, both the peroxide value and total phenol content were optimal parameters to determine the oxidation state. These results thus far indicate the oils, under both flexible packaging, have maintained their original qualitative properties, which can be classified as extra virgin olive oils.