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Dietary fiber (DF) is an important active polysaccharide in Hericium erinaceus. Obesity can lead to a wide range of diseases. In this work, we investigated the in vitro lipid-lowering effect of soluble dietary fiber (SDF) from H. erinaceus, aiming to provide a basis for the subsequent development of lipid-lowering products. Ultrasound-assisted enzymatic extraction (UAEE) of SDF from H. erinaceus was performed. The optimal extraction parameters determined via single-factor experiments and response surface methodology (RSM) were as follows: Lywallzyme concentration, 1.0%; complex protease concentration, 1.2%; ultrasonication time, 35 min; and ultrasonication power, 150 W. In vitro lipid-lowering experiments revealed that the adsorption amount of cholesterol micelles by H. erinaceus SDF was 11.91 mg/g. The binding amount and binding rate of sodium taurocholate were 3.73 mg/g and 42.47%, respectively, and those of sodium glycocholate were 3.43 mg/g and 39.12%, respectively. The pancreatic lipase inhibition rate reached 52.11%, and the type of inhibition was competitive. Therefore, H. erinaceus SDF has good in vitro lipid-lowering ability.

Antioxidant peptides are a class of biologically active peptides with low molecular weights and stable antioxidant properties that are isolated from proteins. In this review, the progress in research on the activity evaluation, action mechanism, and structure-activity relationships of natural antioxidant peptides are summarized. The methods used to evaluate antioxidant activity are mainly classified into three categories: in vitro chemical, in vitro cellular, and in vivo animal methods. Also, the biological effects produced by these three methods are listed: the scavenging of free radicals, chelation of metal ions, inhibition of lipid peroxidation, inhibition of oxidative enzyme activities, and activation of antioxidant enzymes and non-enzymatic systems. The antioxidant effects of natural peptides primarily consist of the regulation of redox signaling pathways, which includes activation of the Nrf2 pathway and the inhibition of the NF-κB pathway. The structure-activity relationships of the antioxidant peptides are investigated, including the effects of peptide molecular weight, amino acid composition and sequence, and secondary structure on antioxidant activity. In addition, four computer-assisted methods (molecular docking, molecular dynamics simulation, quantum chemical calculations, and the determination of quantitative structure-activity relationships) for analyzing the structure-activity effects of natural peptides are summarized. Thus, this review lays a theoretical foundation for the development of new antioxidants, nutraceuticals, and cosmetics.

Pleurotus citrinopilestus contains a variety of physiologically and pharmacologically active compounds. A key active component among these compounds is dietary fiber, a polysaccharide that exhibits several biological properties. The objective of this study was to assess how soluble dietary fiber (SDF) from Pleurotus citrinopilestus responded to ultrasonic-assisted enzymatic (UAE) extraction. The response surface method (RSM) combined with the Box-Behnken design method (BBD) was used to optimize the yield of SDF. The effects of the liquid-solid ratio (35–55 mL/g), α-amylase concentration (0.5–2.5%), complex protease concentration (0.4–2.0%), and ultrasonication time (15–55 min) on the yield of SDF were examined. The RSM results revealed the optimal liquid-solid ratio (45 mL/g), α-amylase concentration (1.5%), complex protease concentration (1.2%), and ultrasonic time (35 min). The SDF yield was 10.25%, which is close to the predicted value (10.08%).