QUALITY EVALUATION OF PROCESSED STRAWBERRY FRUITS

Several strawberry products: whole fruits, strawberry purees (5°Brix) and strawberry concentrates (≥21°Brix), submitted to different processing temperatures (fresh non-pasteurized, enzymatically inactivated and pasteurized) have been characterized in terms of their organoleptic quality. Quality parameters such as color (L, a, b values, Hue, Chroma, browning index, and anthocyanin content), taste (total soluble solids, acidity, sugars and organic acids profile), nutritional value (vitamin C and polyphenols contents) and aroma (volatile compounds) have been analyzed during 12 months of storage at 2°C and -18°C. Although quality changes showed quite different rates in whole fruits, purees, and concentrates, losses of anthocyanins and vitamin C were the most relevant changes observed during storage. In general, storage temperature had a greater effect on quality maintenance than processing temperature, particularly for anthocyanins and vitamin C contents. Thus, frozen non-pasteurized strawberry purees had significantly higher content of anthocyanins and vitamin C than refrigerated products, either previously submitted to thermal enzymatic inactivation and/or pasteurization, which lose 80% vitamin C and 40% anthocyanins after 3 months of storage. On the other hand, the quality standards of the fruits before processing seem to be critical for quality maintenance of the strawberry products.