The Optimization of the Hot Water Extraction of the Polysaccharide-Rich Fraction from Agaricus bisporus

The optimization of extraction parameters, including the process time, temperature, and liquid-to-solid ratio, was conducted in order to obtain the polysaccharide-rich fraction from the lyophilized Agaricus bisporus fruiting body. The efficiency of extraction for polysaccharides and antioxidant activity was determined by analyzing the extracts for total carbohydrate content, the reducing sugars content, and the antioxidant activity employing DPPH, ABTS, and hydroxyl radical scavenging assays. The results showed that all parameters, except for the extraction time, impacted differently on the extraction efficiency of polysaccharides and antioxidant activity. The highest total carbohydrate content was observed at the longest process time, highest temperature, and a liquid-to-solid ratio of 118 mL/g. To minimize the reducing sugar level, a lower temperature is required, while the highest antioxidant activity requires a moderate temperature and the lowest liquid-to-solid ratio. The optimization of antioxidant activity by means of the DPPH and H2O2 method failed, which shows that the specific mechanism of polysaccharides as antioxidants needs further investigation. The aqueous extraction method demonstrated to be an efficient and simple approach to recover the potentially bioactive polysaccharide fractions from Agaricus bisporus that are also active as antioxidants.