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A comparative study on different concentration methods of extracts obtained from two raspberries ( Rubus idaeus L.) cultivars: evaluation of anthocyanins and phenolics contents and antioxidant activity
Author(s) -
Yousefi Ghasem,
Yousefi Shima,
EmamDjomeh Zahra
Publication year - 2013
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/ijfs.12073
Subject(s) - blowing a raspberry , rubus , antioxidant , chemistry , dpph , anthocyanin , cultivar , food science , antioxidant capacity , rosaceae , horticulture , botany , biochemistry , biology
Summary The effects of conventional (CV) and microwave (MW) heating on total soluble solid (TSS) content, total anthocyanin content (TAC), total phenolic content (TPC) and antioxidant activity of raspberry juice obtained from two cultivars of Amol (AM) and Siyahkal (SK) were scrutinised. Antioxidant activity of the juices was measured by 2,2 diphenyl‐1‐picrylhydrazyl (DPPH) radical scavenging capacity and expressed as EC 50 value. In the both methods, the concentration rate constant for the juices was significantly decreased by increasing operational pressure from 12 to 100 kPa ( P < 0.05). A first‐order reaction kinetic model was successfully fitted for the degradation of monomeric anthocyanins at all operating pressures. The results also showed that thermal treatment of MW compared CV in both SK and AM cultivars caused a lower decrease in the TAC, TPC and antioxidant activity. Moreover, the changes in trend of the antioxidant activities due to the thermal treatment were positively correlated with the TPC ( r = 0.74, P < 0.05) and TAC ( r = 0.61, P < 0.05).