Effects of blackberries (Rupus sp.; cv. Xavante) processing on its physicochemical properties, phenolic contents and antioxidant activity

Beneficial health effects are attributed to the wide array of polyphenols such as anthocyanins present in berries. Blackberries have been improved genetically to be cultivated in different climate such as Brazil. Thus, distinctive cultivars were created. However, antioxidant properties of these have not been evaluated. This study aimed to investigate the availability of phenolic compounds in Brazilian cultivar blackberries (cv. Xavante) after processing into purees, coulis and jam changes during storage. Physicochemical, total phenolic compounds (TPC), anthocyanins and antioxidant activity of frozen and processed food products were evaluated. The pH values of jam and frozen pulp increased to a greater extent during storage. Puree A (70 degrees C for 20 min) showed the highest value for lightness and redness on day 1 with a decrease after 30 days of storage. Redness values decreased to a greater extent for puree A, indicating less stable product over time whereas coulis presented optimal stability shown by the smaller color difference value. No differences in TPC were observed for frozen pulp, puree A, puree B, and coulis. Significantly lower amount of TPC was present in the jam indicating degradation of phenolic compounds upon heating and concentration process involved in jam making. An increase in antioxidant activity (ABTS assay) was observed in processed products after storage, which might be related to the development of new compounds with greater antioxidant activity. Therefore, processing of blackberries into food products is an alternative to prolong the accessibility of those fruits without extensive loss of antioxidant activities.