“Koroneiki” olive fruit from trees grown in Crete were stored under five different conditions (0°C, air; 5°C, air; 5°C, 2% O2+5% CO2; 7.5°C, air; 7.5°C, 2% O2+5% CO2). Oil was obtained from fruit immediately after harvest and after fruit storage for 30 and 60 d. Olive oil quality was evaluated by determining acidity, peroxide value, absorption coefficients (K232, K270), phenol and chlorophyll content, fatty acid composition, and the resistance to oxidation by oven test. Olives stored at 7.5°C, even for 30 d, deteriorated from fungus development, and the obtained oil was of inferior quality with high acidity, peroxide value, and absorption coefficients. The same oil had high chlorophyll and phenol content, resulting in good oil resistance to oxidation. Olive oil from fruit stored at 0 or 5°C for 30 d had acceptable acidity, peroxide value, and absorption coefficients, but showed low resistance to oxidation, which was attributed to low chlorophyll and phenol content. This condition is further attributed to chilling injury caused by low storage temperatures. During storage, all treatments resulted in an increase of oleic acid, partly as a result of linoleic acid oxidation.
The effects of water, sorbitol and a sucrose fatty acid ester (SE) on the water sorption behaviour and thermal and mechanical properties of pullulan-based edible ®lms as well as the physiological responses of fruit coated with pullulan have been studied. Incorporation of sorbitol or SE in pullulan ®lms resulted in lower equilibrium moisture contents at low to intermediate water activities (a w ), but much higher moisture contents at a w > 0.75; estimates of monolayer values (within 4.1± 5.9 gH 2 O kg À1 solids) were given by application of the Brunauer±Emmett±Teller (BET) and Guggenheim±Anderson±DeBoer (GAB) models. A single glass±rubber transition (T g ), attributed to the polysaccharide component, was detected by calorimetry and dynamic mechanical thermal analysis (DMTA) at a sorbitol level of 15±30% DM. With both tests the strong plasticising action of water and polyol was evident in the thermal curves, and the T g vs moisture content data were successfully ®tted to the Gordon±Taylor empirical model. Multifrequency DMTA measurements provided estimates for the apparent activation energy of the glass transition in the range of Ä 300±488 kJ mol
À1. With largedeformation mechanical testing, large decreases in Young's moduli (tensile and three-point bend tests) were observed as a result of water-and/or polyol-mediated glass-to-rubber transition of the polymeric ®lms. In the moisture content range of 2±8%, increases in¯exural modulus (E) and maximum stress (s max ) with small increases in moisture content were found for ®lms made of pullulan or pullulan mixed with 15% DM sorbitol; a strong softening effect was observed when the water content exceeded this range. Addition of sorbitol increased the water vapour transmission rate of the ®lms, whereas addition of SE had the opposite effect. Application of a pullulan/sorbitol/SE coating on strawberries resulted in large changes in internal fruit atmosphere composition which were bene®cial for extending the shelf-life of this fruit; the coated fruit showed much higher levels of CO 2 , a large reduction in internal O 2 , better ®rmness and colour retention and a reduced rate of weight loss. In contrast, similar studies on whole kiwifruits showed increased levels of internal ethylene, which caused acceleration of fruit ripening during storage.
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