Giovana Celli - Effect of thawing conditions on polyphenol content and antioxidant activity of frozen haskap berries (Lonicera caerulea L.)

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      Publication Details (including relevant citation   information):

      Authors: Rabie Khattab, Giovana B. Celli, Amyl Ghanem &   Marianne Su-Ling Brooks

      Current Nutrition and Food Science, vol. 11, pp. 223-230

      Abstract:

      The effect of different thawing methods on three haskap berry   (Lonicera caerulea L.) varieties, Tundra (T), Berry Blue (BB) and   Indigo Gem (IG), was investigated. Methods included thawing the   frozen berries at room temperature (25 ± 2 °C), refrigerated   temperature (4 °C) and using a microwave oven. All the berry   varieties were analyzed for their total phenolic content   (TPC)/total reducing capacity (TRC), total anthocyanin content   (TAC) and antioxidant potential (DPPH radical scavenging   activity). The TPC/TRC, TAC and DPPH scavenging activity ranges   in the fresh fruits were 6.17-8.42 mg GAE/ g FW, 4.49-6.97 mg   C-3-G E/ g FW, and 78.70-89.55 %, respectively. Frozen storage   for six months followed by consequent thawing at the standard   conditions (room temperature) caused 35.85-44.73, 32.14-53.23,   and 26.28-29.57 % reductions in the TPC/TRC, TAC, and DPPH   scavenging activity, respectively. The highest reduction occurred   in the Berry Blue variety followed by that of Indigo Gem.   Refrigerated thawing did not significantly improve the retention   of phenolic compounds and anthocyanins. Microwave thawing could   be achieved in significantly shorter time (17.31 min) as compared   to room temperature (12.00 h) and refrigerated thawing (22.00 h)   and could significantly improve the retention of phenolics,   anthocyanins and antioxidant potential. The corresponding   reductions in the TPC/TRC, TAC, and DPPH scavenging activity of   different varieties ranged from 24.97%-39.87%, 18.92%-47.22%, and   21.39%- 27.29 %, re-spectively. Thus, further investigation into   the industrial application of microwave thawing is recommended to   maximize the retention of bioactive compounds in products   manufactured from frozen haskap berries.

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