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Steam explosion pretreatment was conducted on seabuckthom pomace. Response surface methodology was used to optimize the treatment conditions of steam explosion, including steam pressure, duration and particle size. After this, the content of total flavonoids and the antioxidant capacity of total flavonoids were investigated. Results showed that when the steam pressure was 2.0 MPa, duration was 88 s and a sieving mesh size was 60, the total flavonoids content in seabuckthorm reached a maximum of 24.74 ± 0.71 mg CAE/g, an increase of 246% compared with that without steam explosion treatment (7.14 ± 0.42 mg CAE/g). Also, DPPH and ·OH free radical scavenging ability showed significant improvement, with an IC50 decrease to 13.53 μg/mL and 4.32 μg/mL, respectively, far lower than that in original samples. Through the scanning electron microscope, the surface of seabuckthom pomace after steam explosion was crinkled, curly, and holey. Our study showed that the content of total flavonoids in seabuckthom pomace could be obviously promoted and the antioxidant capacity of total flavonoids also improved significantly, after applying steam explosion pretreatment to seabuckthom pomace, making this approach meaningful for the reuse of seabuckthom pomace resources.

In this study, the pine nut (Pinus yunnanensis Franch.) protein was hydrolyzed by alkaline protease and trypsin to prepare pine nut protein hydrolysate (PNPH). The chemical, intracellular and in vivo antioxidant capacity of PNPH were evaluated. PNPH owned the ability of scavenging free radicals, and it could protect the HepG2 cells from oxidative damage by preserving cell viability. Moreover, PNPH could reduce the malondialdehyde (MDA) content and improved the superoxide dismutase (SOD) and glutathione peroxidase (GSH-Px) activities in serum, heart and liver of aging mice induced by D-galactose. Further, the PNPH was stepwise purified and identified, and 15 peptides were identified from purified fraction in PNPH. The three-dimension structures of identified peptides were predicted. Among all identified peptides, peptide 3, 7, 8 and 11 were presumed to possess good antioxidant activity. Overall, PNPH and purified peptides isolated from PNPH have potential application prospects in the field of natural antioxidants and anti-aging functional foods.

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A novel polysaccharide fraction (HEP) from Hericium erinaceus was successively isolated and purified in the present study. We researched its structure and thermal stabilities, and further studied its antioxidant activities in vitro. The results showed that HEP was an acid heteropolysaccharide, with an average molecular weight of approximately 19.7 kDa by high‐performance gel permeation chromatography. Ion chromatography indicated that HEP was mainly composed of fucose:galactose:glucose:mannose:gluconic acid (Fuc:Gal:Glu:Man:GlcA) in a molar ratio of 1:2.87:0.09:0.12:0.01. Additionally, Fourier‐transformed infrared and NMR spectroscopy further demonstrated that HEP was a pyranose containing α‐configuration, mainly consisting of α‐1‐4‐Fuc and α‐1‐6‐Gal as the main chain, with →3,6)‐α‐D‐Man‐(1→and→1,6)‐Glc was branched, with α‐D‐GlcpA‐(1 as T‐terminal. The specific rotation of HEP was +55°; by the differential scanning calorimetry and the thermal stability measurement of thermogravimetric analysis for HEP showed that the pyrolysis process of HEP was mainly divided into two processes, and its melting point was 75.93℃. In vitro anti‐oxidation experiments showed that HEP had a certain ability to scavenge DPPH, hydroxyl, superoxide anion, and ABTS radicals. It was found that HEP had a strong ability to scavenge DPPH‐free radicals, and the highest scavenging rate could reach 91.72% ± 0.17%, which was basically equivalent to the scavenging ability of Vitamin C (Vc). Therefore, it was revealed that HEP might be used as a natural antioxidant component. Practical applications A novel polysaccharide (HEP) had a potent activity possibly due to its monosaccharide composition, sugar residues, and physicochemical properties. This research proved the potential of HEP in anti‐oxidation and provided the possibility of developing new natural anti‐oxidation products.