Effect of heating and acidification on total phenolic content and antioxidant activity of date palm pit extract

Phenolic compounds are useful ingredients of date palm pit and usually exert high antioxidant activity. The aim of present study was to investigate the effect of heating and acidification on total phenolic content and antioxidant activity of date palm pit extract by using the Folin–Ciocalteau and ABTS reagents، respectively. Results showed that total phenolic content increased with increasing the heating temperature (70–110 °C) and time (10–40 minutes). The palm pit extract treated at longer heating times exhibited higher antioxidant activity. However، acidification of pit extract from its inherent pH 6. 23 to 1. 51 led to a decrease in total phenols content from 1582 to 1068 mg gallic acid equivalent per 100 g dry weight. Acidification also caused a decrease in antioxidant activity. The results of simultaneous heating and acidification treatments showed that increasing influence of heating on total phenolic content was more effective than decreasing influence of acidification on phenols content.