| heal.abstract |
The effects of package atmosphere and temperature on phenolic compounds, total antioxidant capacity and colour were investigated in kernels of 'Franquette' walnuts stored for up to 8 months. Dried walnuts were sealed under air or 100% N 2 and stored at 1°C or 20°C. The highest total phenolics concentration (25.41 mg gallic acid equivalents g -1) and total antioxidant capacity (185.6 μmol trolox equivalents g -1, and 174.2 μmol trolox equivalents g -1 according to FRAP and DPPH method, respectively) were observed in samples before storage. The above parameters decreased progressively during storage. Low temperature and N 2-atmosphere inhibited decline while their combination provided best preservation of nutritional value. Additive effects of low temperature and N 2-atmosphere were also observed in retention of L * and hue angle colour parameters while Chroma was affected only by temperature. Major phenolic compounds were ellagic, protocatechuic, vanillic, and syringic acids and found at concentrations of 822.4 μg g -1, 581.8 μg g -1, 581.6 μg g -1, and 310.2 μg g -1, respectively. At the end of storage all phenolic compounds decreased and the decrease was most pronounced in air at 20°C (54% of all compounds, in average) and less in N 2-atmosphere at 1°C (18% of all compounds, in average). |
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