Effect of Biological Combined with Ultrasonic Extraction and Solvent Extraction on Resveratrol and Anthocyanin Content of Ripe Mulberry Fruits

Abstract

Resveratrol and anthocyanins are important photochemicals that had high potential for health benefits.  Thailand can produce a lot of mulberry fruits that are able to use for as raw material for resveratrol and anthocyanin extraction. This research aimed to find out the optimal process for resveratrol and anthocyanin extracted from ripe mulberry fruits. Mulberry fruits from Chiang Mai variety which were harvested from mixed ripening stage were suitable for using as raw material, because of its high value of resveratrol and anthocyanin content.  In this study, two extraction methods were investigated; biological extraction and solvent extraction methods. From biological extraction without ultrasonic treatment and without deacidification, it was found that resveratrol content was increased during yeast fermentation.  After filtration, fermented mulberry fruit solution had very high recovery value of resveratrol (331.97%) from fresh ripe mulberry fruits.  From solvent extraction, preliminary dehydration of fresh ripe mulberry fruits decreased the amount of resveratrol and anthocyanin content. So that fresh ripe mulberry fruits without dehydration was suitable to use as raw material.  Mulberry juice and cake was obtained from hydraulic pressing of fresh ripe mulberry fruits. It was found that mulberry fruit cake had high resveratrol content approximately 2/3 of whole resveratrol content. In this study, mulberry fruit cake was selected as raw material for solvent extraction.  Room temperature extraction of mulberry fruit cake with mixed solvent (ethanol:ethyl acetate = 50:50) at the ratio of 1:5 for 1 hour soaking time could provided 104.24% of resveratrol recovery from fresh ripe mulberry fruits. According to resveratrol recovery, the high potential method for resveratrol extract should be biological extraction. The extract solution with high resveratrol content could be utilized as concentrate or powder forms.