Search

BACKGROUND Ginkgotoxin including 4′‐O‐methylpyridoxine (MPN) and MPN‐5′‐glucoside (MPNG) is responsible for Ginkgo seed food poisoning. The purpose of the work reported was to prepare detoxified Ginkgo seed powder and at the same time to retain the nutritional and functional components of Ginkgo seed powder to the maximum extent. RESULTS: Resin adsorption technology was firstly employed to remove ginkgotoxin from water extract of Ginkgo seed powder. Under optimal conditions, the adsorption efficiency of the optimal resin for MPN could reach 100%, and that for MPNG could only reach 85.4 ± 0.93%. Resin adsorption alone could not effectively remove MPN and MPNG simultaneously. Endogenous enzymatic hydrolysis was next attempted to transform MPNG to MPN. MPNG could be completely hydrolyzed to MPN by endogenous enzyme(s) at 40 °C and pH 5.0 in 180 min. Ginkgotoxin only in the form of MPN in the enzymatic hydrolysate was then adsorbed with resin and the conditions were statistically optimized. The adsorption efficiency of MPN reached 98.89 ± 0.99% under the optimized conditions. CONCLUSIONS: Removal of ginkgotoxin by combining endogenous enzymatic hydrolysis with resin adsorption could preserve the main nutritional and functional components of Ginkgo seed powder to the most extent, and did not change its main characteristics. The ginkgotoxin removal method developed in this work is a relatively simple and efficient approach. © 2020 Society of Chemical Industry [ABSTRACT FROM AUTHOR]

Graphical abstract Highlights • Low-cost enzyme cocktail with high xylanase activity was produced by A. niger. • Wheat straw was hydrolyzed more effectively than other biomass by the enzyme cocktail. • Xylanase combined with cellulase significantly enhanced the hydrolysis of wheat straw. • Delignification was more efficient than de-hemicellulose for wheat straw hydrolysis. • Crystallinity is little interference with the hydrolysis process of wheat straw. Abstract Based on a general understanding that hemicellulose removal is more efficient than delignification for biomass deconstruction, an Aspergillus niger strain producing high xylanase activity was screened out from seventeen strains by clear halo experiments. Low-cost enzyme cocktail with high xylanase activity was produced from wheat straw medium fermented by the Gyx086 strain. The enzyme cocktail with high xylanase activity could more effectively hydrolyze wheat straw than other biomasses. However, only 30% of total carbohydrates could be hydrolyzed to reducing sugar in untreated wheat straw. Further enzymatic hydrolysis and pretreated trials were carried out, the results indicated that hemicellulose removal was less effective than delignification for de-recalcitrance of wheat straw and the crystallinity is little interference with the hydrolysis process. Delignified wheat straw was near-completely hydrolyzed by the enzyme cocktail in 60 h. This study advanced the knowledge in promoting wheat straw as feedstock for bio-based industry. [ABSTRACT FROM AUTHOR]

Kaempferol (kae) and its glycosides are widely distributed in nature and show multiple bioactivities, yet few reports have compared them. In this paper, we report the antitumor, antioxidant and anti-inflammatory activity differences of kae, kae-7-O-glucoside (kae-7-O-glu), kae-3-O-rhamnoside (kae-3-O-rha) and kae-3-O-rutinoside (kae-3-O-rut). Kae showed the highest antiproliferation effect on the human hepatoma cell line HepG2, mouse colon cancer cell line CT26 and mouse melanoma cell line B16F1. Kae also significantly inhibited AKT phosphorylation and cleaved caspase-9, caspase-7, caspase-3 and PARP in HepG2 cells. A kae-induced increase in DPPH and ABTS radical scavenging activity, inhibition of concanavalin A (Con A)-induced activation of T cell proliferation and NO or ROS production in LPS-induced RAW 264.7 macrophage cells were also seen. Kae glycosides were used to produce kae via environment-friendly enzymatic hydrolysis. Kae-7-O-glu and kae-3-O-rut were hydrolyzed to kae by β-glucosidase and/or α-L-rhamnosidase. This paper demonstrates the application of enzymatic catalysis to obtain highly biologically active kae. This work provides a novel and efficient preparation of high-value flavone-related products. [ABSTRACT FROM AUTHOR]

The purpose of this work was to study the combined effect of high hydrostatic pressure (HHP) and enzymatic hydrolysis treatment on the hydrolysis and allergenicity of ginkgo seed proteins (GSPs). Four food-grade proteases (papain, alcalase, pepsin, and neutrase) were used, and HHP (200, 300, and 400 MPa separately) was applied prior to hydrolysis. The extent of hydrolysis was measured with the o-phthaldialdehyde method, SDS-PAGE, and MALDI-TOF-MS, and the allergenicity was assessed with a Western blot and enzyme-linked immunosorbent assay (ELISA). The results showed that HHP could significantly improve the extent of proteolysis by papain, alcalase, or pepsin and reduce the antigenicity of GSP, whereas neutrase showed poor effects at any pressure. Papain and alcalase showed the highest proteolysis at 300 MPa, followed by pepsin at 400 MPa, and all of the obtained hydrolysates showed molecular weights lower than 10 kDa; furthermore, papain or alcalase at 300 MPa as well as pepsin at 400 MPa reduced antigenicity by more than 95 %, and all of the immunoreactive bands disappeared in the obtained hydrolysates. These results suggest that HHP can enhance the hydrolysis of GSP by certain enzymes and reduce the residual antigenicity of the hydrolysates. The obtained hypoallergenic hydrolysates could be used as a source of peptides for food ingredients. [ABSTRACT FROM AUTHOR]

• Overconsumption of Ginkgo biloba seeds leads to poisoning. • 4'-O-methylpyridoxine (MPN) and MPN-5'-glucoside (MPNG) are responsible for poisoning. • Heat treatment could increase the MPNG content but decrease the MPN content. • Non-enzymatic and enzymatic glycosylation could not explain the transformation. • Enzymatic hydrolysis could explain the dynamic relationship between the MPN and MPNG. Overconsumption of Ginkgo biloba seeds leads to poisoning. 4'-O-methylpyridoxine (MPN) and 4'-O-methylpyridoxine-5'-glucoside (MPNG) are responsible for poisoning by intaking ginkgo seeds. It had been reported that heat treatment could increase the MPNG content but decrease the MPN content in ginkgo seeds. However, the definite mechanism for the transformation of MPN and MPNG in ginkgo seeds undergoing heat treatment has not been elucidated to this day. In this work, a Chinese ginkgo cultivar was firstly employed to investigate the effect of heat treatment on the levels of MPN and MPNG. Similar syngenetic succession between the MPN and MPNG contents was also found. Several groups of experiments were further designed to explore the interconversion mechanism between MPN and MPNG under heat treatment. The results showed that non-enzymatic and enzymatic glycosylation mechanisms could not explain the transformation between MPN and MPNG. Enzymatic hydrolysis mechanism could better explain the dynamic relationship between the MPN and MPNG. Therefore, inactivating the endogenous enzymatic hydrolysis before HPLC analysis is needed to accurately determine the contents of MPN and MPNG in the ginkgo seeds. [ABSTRACT FROM AUTHOR]