Isolation and antioxidant activity of protein-polysaccharide complex from dried longan pulp
The objective of this study was to evaluate the antioxidant ability in vitro of the protein-polysaccharide complex extract from longan after the drying. The dried longan pulp at a certain ratio of solid to liquid (1/25, W/W), was stirred with hot water at 50°C for 3 h at pH 6, leached, concentrated, centrifuged, dialyzed, and freeze-dried to obtain dried longan pulp protein-polysaccharide complex (LDC). The antioxidant activities of LDC were evaluated by ferric ion reducing antioxidant power (FRAP), total reducing power and ABTS+ clearance rate. The results showed that the LDC had obvious capability of reducing Fe3+, total reducing power and ABTS+ scavenging capacity, and had a significant positive correlation with its concentration. At a concentration of 5 mg mL‑1, the LDC of dried longan pulp obtained the highest FRAP value (0.71±0.02 mmol L‑1), while at a concentration of 800 µg mL‑1, the LDC obtained the highest ABTS+ scavenging capacity (96.16±1.36%). Therefore, the LDC produced from dried longan pulp showed strong antioxidant ability and can be used as a primary antioxidant. In conclusion, these results provided more theoretical guideline for improving the bioavailability of longan, and the development of more deep-processed products such as longan health products.
Wang, T., Wang, K., Zhao, L. and Hu, Z. (2020). Isolation and antioxidant activity of protein-polysaccharide complex from dried longan pulp. Acta Hortic. 1293, 269-274
dried longan, protein-polysaccharide complex, antioxidant activity