Study on physicochemical properties and antioxidant activities of melanoidins extracted from low thermal induced black Lycium barbarum L.

Abstract

In this study, static and dynamic desorption methods, infrared spectroscopy and, in vitro antioxidant modeling were used to isolate, purify, and investigate the bioactivity of melanoidins extracted from hypoheat-induced Lycium barbarum L. The results showed that melanoidin fractions with molecular weight in the range of 3−10 kDa were the dominant and most valuable fractions. In the purification phase, the optimal purification conditions were: a loading concentration of 4 mg·mL ⁻¹, elution volume of 6 BV, and an elution flow rate of 1 mL·min ⁻¹. Purified dominant melanoidin fractions (UF3) exhibited typical Maillard reaction (MR) characteristics in FTIR. The storage stability showed that sunlight and heat treatment exacerbated the instability of the purified UF3. At the same time it was relatively stable under dark conditions and incandescent light, with a retention rate of about 90%. After in vitro digestion, the purified UF3 still exhibited good antioxidant activity, and the DPPH scavenging activity and hydroxyl free radical scavenging ability reached more than 60%.

Keywords

Melanoidins / Low thermal induced / Purification / Antioxidant activity / In vitro digestion