The effect of cultivar and extraction method on antioxidant activity of date pit extract of some date cultivars in Bushehr province

Bioactive compounds such as polyphenols and fibers in plant products are recognized for their health benefits . The beneficial effects of phenolic compounds are related to their antioxidant properties . The date seed is a waste of the date processing factories. Depending on the variety, the average weight of date seeds is about 10 - 15 % of date weight and as a source of dietary fiber . The purpose of this study was to compare the effect of traditional extraction methods (maceration) and ultrasound on the amount of phenolic and flavonoid compounds extracted from the three date seed varieties of Kababak, Zahedi and Astamaran in Bushehr Province and their antioxidant properties .

Date kernels were separated from the fruit and then washed with water to remove the flesh and finally dried and powdered. The maceration method was used to extract the powder . In order to investigate the effect of ultrasonic process on extraction of phenolic and flavonoid compounds, (5 , 15 , 25 minutes) and sound intensity ( 50 and 100 % ) were used . Total phenols and flavonoids were measured by Folin - Ciocalteu and aluminum trichloride colorimetry . Antioxidant activity was also determined by two methods of free radical scavenging DPPH and ABTS .

Comparison between the two extraction methods showed that the efficiency of extraction of the effective compounds of the seeds of all three varieties in the ultrasound method was higher than that of the maceration method . The most effective extraction efficiency of the compounds is 10 minutes and the sound intensity is 100 % . The results of antioxidant assays showed that the hydroalcoholic extracts of the kernels of three date cultivars are concentration dependent in free radical scavenging activity and with increasing concentration, their activity increases. Recent research showed that with the presence of phenol (29.34 mg / g of gallic acid ) and flavonoid (1282.66 µg/mg of quercetin), the most of Zahedi variety seed extract, Kababab variety has the highest antioxidant activity .

It can be said that the seed powder of Zahedi, Kabakab and Astamaran is a good source of fiber, carotenoids and mineral elements. Therefore, based on this research, powder and seed extract of various date varieties can be used as natural antioxidant compounds in different foods .