Investigation of the formation mechanism of the pepper starch-piperine complex.

In this study, a new carrier for loading piperine was prepared using pepper starch, and its interaction mechanism was investigated. The porous pepper starch-piperine complex (PPS-PIP) showed higher loading efficiency (76.15 %) compared to the porous corn starch-piperine complex (PCS-PIP (52.34 %)). This may be ascribed to the hemispherical shell structure of porous pepper starch (PPS) compared to the porous structure of porous corn starch (PCS) based on the SEM result. PPS-PIP had smaller particle size (10.53 µm), higher relative crystallinity (38.95 %), and better thermal stability (87.45 °C) than PCS-PIP (17.37 µm, 32.17 %, 74.35 °C). Fourier transform infrared spectroscopy (FTIR) results implied that piperine not only forms a complex with amylose but may also be physically present in porous starch. This was demonstrated by the short-range order and X-ray type. Molecular dynamics simulations confirmed that hydrogen bonding is the primary interaction between amylose and piperine. Besides the formation of the amylose-piperine complex, some of the piperine is also present in physical form.

Structural characterization of polysaccharides after fermentation from Ganoderma lucidum and its antioxidant activity in HepG2 cells induced by H2O2.

In this study, Lactiplantibacillus plantarum ATCC14917 was used to ferment Ganoderma lucidum spore powder. Two polysaccharides were purified from unfermented (GLP) and fermented (FGLP) Ganoderma lucidum spore powder. The chemical structure and antioxidant activity of the polysaccharides were studied. Finally, the effect of GLP and FGLP on the oxidative stress regulation pathway in HepG2 cells was explored. The results showed that the main structural characteristics of Ganoderma lucidum polysaccharides remained unchanged during the fermentation. However, the average molecular weight (Mw) of Ganoderma lucidum polysaccharides decreased from 1.12 × 105 Da to 0.89 × 105 Da. Besides this, the contents of mannose, galactose, and glucuronic acid increased, while the contents of xylose and glucose were decreased. In addition, the content of uronic acid was raised, and the apparent structure was changed from smooth and hard to porous and loose. In antioxidant studies, intracellular ROS and MDA contents in the oxidative stress model were decreased, and T-AOC content was increased under GLP and FGLP intervention. In the investigation of the regulation pathway, Nrf-1 gene expression was up-regulated, and Keap1 gene expression was down-regulated under GLP and FGLP intervention. The antioxidant genes NQO1 and NO-1 expressions were increased to activate the activities of antioxidant enzymes CAT, SOD and GSH-PA to resist oxidative stress. Compared with GLP, FGLP has a stronger regulatory role in this pathway, thus showing more potent antioxidant activity. This experiment is beneficial to the further utilization of Ganoderma lucidum spore powder.

Physicochemical properties and in vitro digestibility of highland barley starch with different extraction methods.

The objective of this study was to compare the structural, thermal, rheological and digestive properties of highland barley starch (HBS) by different extraction methods. Five techniques were used to extract HBS: Alkali extraction, Ultrasound extraction, double enzyme extraction (DE), three enzyme extraction (TE) and ultrasonic assisted TE (U-TE). The results indicated that the Ultrasound extracted HBS had fewer Maltese crosses, lower molecular weight (Mw), and higher content of damaged starch (P < 0.05). Meanwhile, DE extracted HBS had higher Mw, and the content of short amylopectin than that of Alkali extracted HBS (P < 0.05). Additionally, the DE extracted HBS showed the highest relative crystallinity and good short-range ordered structure, which led to the outcome of stronger thermal stability and higher values of G' and G'' (P < 0.05). These results indicated that enzymatic extraction could better protect the resistance of HBS by protecting its physicochemical properties.

Effects of Different Extraction Methods on the Gelatinization and Retrogradation Properties of Highland Barley Starch.

The purpose of this study was to compare the gelatinization and retrogradation properties of highland barley starch (HBS) using different extraction methods. We obtained HBS by three methods, including alkali extraction (A-HBS), ultrasound extraction (U-HBS) and enzyme extraction (E-HBS). An investigation was carried out using a rapid viscosity analyzer (RVA), texture profile analysis (TPA), differential scanning calorimetry (DSC), X-ray diffraction (XRD) and Fourier-transform infrared spectrometry (FTIR). It is shown that the different extraction methods did not change the crystalline type of HBS. E-HBS had the lowest damaged starch content and highest relative crystallinity value (p < 0.05). Meanwhile, A-HBS had the highest peak viscosity, indicating the best water absorption (p < 0.05). Moreover, E-HBS had not only higher G' and G″ values, but also the highest gel hardness value, reflecting its strong gel structure (p < 0.05). These results confirmed that E-HBS provided better pasting stability and rheological properties, while U-HBS provides benefits of reducing starch retrogradation.

Oat ß-glucan and L-arabinose synergistically ameliorate glucose uptake in insulin-resistant HepG2 cells and exert anti-diabetic activity via activation of the PI3K/AKT pathway in db/db mice.

Oat ß-glucan (OBG) and L-arabinose (LA) have exhibited positive effects on diabetes and its complications. However, it is unclear whether OBG and LA have a synergistic effect. We investigated the effect of variable compositions (OBG : LA = 1 : 1, 1 : 2, 1 : 4,1 : 6, 1 : 8, 1 : 10, 2 : 1, 4 : 1, 6 : 1, 8 : 1, 10 : 1) on glucose uptake in IR-HepG2 cells induced by dexamethasone (DEX) to find out the optimal composition showing synergistic effects. Furthermore, this study evaluated the anti-diabetic activity of the optimal composition in db/db mice. In vitro, the OBG : LA = 1 : 1 group showed the strongest synergistic effects among the varied compositions, outperforming OBG and LA alone. In vivo, there were more beneficial effects in the OBG : LA = 1 : 1 group compared with the OBG and LA single-dosing groups. OBG : LA = 1 : 1 supplementation markedly decreased the levels of fasting blood glucose (FBG) and insulin (INS) in serum, improved glucose tolerance and insulin sensitivity, lowered blood lipid levels, and reduced liver lipid accumulation. Moreover, the western blot results indicated that the OBG : LA = 1 : 1 group up-regulated the protein expression of glucose transporter-4 (GLUT4), phosphatidylinositol 3-kinase (PI3K), and phospho-protein kinase B (p-AKT), while down-regulating the protein expression of phospho-phosphorylated insulin receptor substrate-1 (p-IRS1) to enhance insulin transduction in liver tissues. These findings suggest that OBG : LA = 1 : 1 synergistically ameliorated glucose metabolism disorders and alleviated insulin resistance by promoting the PI3K/AKT pathway in the liver.

Optimization of fermentation for γ-aminobutyric acid (GABA) production by yeast Kluyveromyces marxianus C21 in okara (soybean residue).

γ-Aminobutyric acid (GABA) is a non-protein amino acid with a variety of physiological functions. Recently, yeast Kluyveromyces marxianus strains involved in the catabolism and anabolism of GABA can be used as a microbial platform for GABA production. Okara, rich in nutrients, can be used as a low-cost fermentation substrate for the production of functional materials. This study first proved the advantages of the okara medium to produce GABA by K. marxianus C21 when L-glutamate (L-Glu) or monosodium glutamate (MSG) is the substrate. The highest production of GABA was obtained with 4.31 g/L at optimization condition of culture temperature 35 °C, fermentation time 60 h, and initial pH 4.0. Furthermore, adding peptone significantly increased the GABA production while glucose and vitamin B6 had no positive impact on GABA production. This research provided a powerful new strategy of GABA production by K. marxianus C21 fermentation and is expected to be widely utilized in the functional foods industry to increase GABA content for consumers as a daily supplement as suggested.

Preparation and Characterization of Pickering Emulsions with Modified Okara Insoluble Dietary Fiber.

Modified okara insoluble dietary fiber (OIDF) has attracted great interest as a promising Pickering emulsifier. At present, the modification methods are mainly physicochemical methods, and the research on microbial modified OIDF as stabilizer is not clear. In this work, modified OIDF was prepared by yeast Kluyveromyces marxianus fermentation. The potential of modified OIDF as a Pickering emulsifier and the formation and stability of OIDF-Pickering emulsions stabilized by modified OIDF were characterized, respectively. The results showed that the specific surface area, hydrophilicity, and electronegativity of the modified OIDF were all enhanced compared with the unmodified OIDF. The existence of the network structure between droplets is the key to maintain the stability of the emulsions, as indicated by Croy-Scanning Electron Microscope (Croy-SEM) and rheological properties measurements. The stability of OIDF-Pickering emulsions was evaluated in terms of storage time, centrifugal force, pH value, and ionic strength (NaCl). Moreover, the OIDF-Pickering emulsions stabilized by modified OIDF showed better stability. These results will contribute to the development of efficient OIDF-based emulsifiers, expand the application of emulsions in more fields, and will greatly improve the high-value utilization of okara by-products.

Characteristics of lipoxygenase-based and lipoxygenase-deficient soy yogurt with modified okara.

Lipoxygenase-based and lipoxygenase-deficient okara were modified by Kluyveromyces marxianus fermentation, then adding modified okara back to the corresponding soymilk to prepare soy yogurt. The physicochemical properties, texture, and volatile components of soy yogurt were characterized. The results showed that okara modified by Kluyveromyces marxianus fermentation was rich in soluable dietary fiber and was imparted better water-holding capacity, swelling capacity, and oil-holding capacity. The soy yogurt with the modified okara was greatly enhanced in its appearance, texture and was relatively stable during storage. Moreover, lipoxygenase-based soy yogurt had a unique soybean flavor while lipoxygenase-deficient soy yogurt had a slight beany flavor and soybean flavor. This article guides a bio-modified method for okara and provides a theoretical basis for the further development and application of soy yogurt with high dietary fiber as well as lipoxygenase-deficient soy yogurt. SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1007/s10068-021-01003-w.

Hepatoprotective effects of flavonoids from common buckwheat hulls in type 2 diabetic rats and HepG2 cells.

Flavonoids from common buckwheat hulls (BHFs) show significant antioxidant and antidiabetic potential. However, their hepatoprotective property is yet to be defined. This study aims to examine the hepatoprotective effect of BHFs in type 2 diabetes mellitus (T2DM) rats and chronic high glucose-damaged HepG2 cells. Results showed that BHF treatment significantly relieves the state of insulin resistance, thereby reducing blood glucose and improving oxidative stress in T2DM rats. It is worth mentioning that BHF treatment improved diabetes-induced liver damage disorders, manifested as the clearance of liver fat and the decline of serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) activities. In vitro, HepG2 cells pretreated with BHFs maintained higher superoxide dismutase (SOD), glutathione peroxidase (GSH-px), and catalase (CAT) activities than the unprotected group. In parallel, compared with the unprotected group, BHFs significantly reduced the leakage of ALT and AST in pre-protected group dose-dependently. These results indicated that BHFs had considerable antioxidant and hepatoprotective potential and could be promising to be used as nutraceuticals and dietary supplements to prevent and/or protect against liver disorders.

Pediococcus pentosaceus PP04 improves high-fat diet-induced liver injury by the modulation of gut inflammation and intestinal microbiota in C57BL/6N mice.

In this study, Pediococcus pentococcus PP04 (PP04) isolated from the Northeast pickled cabbage was given to C57BL/6N mice for eight weeks, aiming to investigate the ameliorative effects of PP04 on liver injury induced by a high-fat diet. The western blot results suggested that PP04 ameliorated the increase of intestinal permeability by dramatically increasing the expressions of tight junction proteins, such as Occludin, Claudin-1 and ZO-1, which decreased hepatic lipopolysaccharides (LPS), alanine aminotransferase (ALT) and aspartate aminotransferase (AST) concentrations to effectively alleviate the liver injury. Furthermore, PP04 relieved the high-fat diet-caused gut inflammation by the NF-κB/Nrf2 signaling pathway, which regulated the expression of inflammatory cytokines and antioxidants, to positively improve the liver injury. In addition, the 16S rDNA sequencing results inferred that PP04 had the potential to rebalance intestinal flora disorders through regulating the relative abundance of inflammation and obesity-related bacteria in mice.

Flavonoids derived from buckwheat hull can break advanced glycation end-products and improve diabetic nephropathy.

Diabetic nephropathy (DN) is the most important complication in patients with diabetes. The accumulation of advanced glycation end-products (AGEs) is the main reason for the development of DN. In this study, we investigated the mechanism of buckwheat hull flavonoids to break AGEs in vitro by measuring fluorescence analysis, three-dimensional fluorescence, protein molecular weight, free amino groups, and the sulfhydryl group content. Proteomics analysis was used to determine the effect of total buckwheat hull flavonoids (TBHF) intervention on protein differential expression in the kidney of db/db mice. The results showed that buckwheat hull flavonoids were potent in breaking AGEs in vitro, and they protected mice kidneys by regulating the renal AGE-RAGE pathway. This study lays a strong experimental and theoretical foundation for the development of new lysing agents to break AGEs. The findings should make an important contribution to the field of flavonoids in improving the application of diabetic nephropathy in the diet.

Production of ß-glucosidase from okara fermentation using Kluyveromyces marxianus.

The effective utilization of okara (soybean residue) has become a considerable challenge in recent years. In this paper, the potential advantages of ß-glucosidase production from okara fermented by Kluyveromyces marxianus were evaluated and the properties of the ß-glucosidase were also characterized. The results showed that okara can significantly induce the production of ß-glucosidase from K. marxianus. The ß-glucosidase activity was up to 4.5 U/mg under optimized fermentation conditions. The optimal parameters were as follows: fermentation temperature 35 °C, cultivation time 98 h, inoculum concentration 10%, and 30 g/L of okara. After two steps of purification using ammonium sulfate precipitation and Sephadex G-75 column chromatography, the activity of ß-glucosidase was 71.4 U/mg. The native enzyme was an approximately 66 kDa dimer consisting of two different subunits (22 and 44 kDa). The kinetic parameters of the K. marxianus ß-glucosidase, using pNPG as substrate, were V max 8.34 µmol min-1 mg-1 and K m 7.42 mM. The ß-glucosidase showed high thermostability and acid-alkali tolerance as well as low inhibition by DMSO (10-50%). In conclusion, this study supports the notion that okara fermentation by K. marxianus could be a useful process to produce ß-glucosidase.

Synergistic Two-Way Interactions of Dietary Polyphenols and Dietary Components on the Gut Microbial Composition: Is There a Positive, Negative, or Neutralizing Effect in the Prevention and Management of Metabolic Diseases?

Polyphenol is an intricate bioactive molecule abundant in humans/animals' diet particularly plant foods, and has been evidenced in numerous reports with health-promoting functions, owing to its free radical scavenging properties and a broad spectrum of bioactivities. However, the beneficial functions are linked and restricted to bioavailability, which is dictated by the diversity of the gut microbiota. The human/animal's gut harbours a complex community of trillions of microbial species and their symbiotic relationship goes beyond mere aiding the host's digestive system, with important functions such as host nutrition and health by encouraging nutrient metabolism and absorption, regulation of the gastrointestinal development, protection against pathogens, maintenance of the gut mucosal barrier functions and host immune system. The disruption of the gut community (i.e., dysbiosis) is suggested to reflect several pathological processes, such as diabetes, obesity, and other metabolic-related comorbidities. Recent improvements in deep-sequencing technologies and bioinformatics have enabled a more complex understanding of the reciprocal interactions of dietary polyphenols and gut microbiota, as well as their metabolic impact. Hence this review seeks to discuss the two-way synergistic interactions of dietary polyphenols and dietary constituents on the gut microbial composition with an updated and pivotal finding from literature suggesting whether these interactions depict a positive, negative, or neutralizing effect in the prevention of metabolic diseases.

Prebiotic Impacts of Soybean Residue (Okara) on Eubiosis/Dysbiosis Condition of the Gut and the Possible Effects on Liver and Kidney Functions.

Okara is a white-yellow fibrous residue consisting of the insoluble fraction of the soybean seeds remaining after extraction of the aqueous fraction during the production of tofu and soymilk, and is generally considered a waste product. It is packed with a significant number of proteins, isoflavones, soluble and insoluble fibers, soyasaponins, and other mineral elements, which are all attributed with health merits. With the increasing production of soy beverages, huge quantities of this by-product are produced annually, which poses significant disposal problems and financial issues for producers. Extensive studies have been done on the biological activities, nutritional values, and chemical composition of okara as well as its potential utilization. Owing to its peculiar rich fiber composition and low cost of production, okara might be potentially useful in the food industry as a functional ingredient or good raw material and could be used as a dietary supplement to prevent varied ailments such as prevention of diabetes, hyperlipidemia, obesity, as well as to stimulate the growth of intestinal microbes and production of microbe-derived metabolites (xenometabolites), since gut dysbiosis (imbalanced microbiota) has been implicated in the progression of several complex diseases. This review seeks to compile scientific research on the bioactive compounds in soybean residue (okara) and discuss the possible prebiotic impact of this fiber-rich residue as a functional diet on eubiosis/dysbiosis condition of the gut, as well as the consequential influence on liver and kidney functions, to facilitate a detailed knowledge base for further exploration, implementation, and development.

Effect of pullulan concentration and pH on the interactions between whey protein concentrate and pullulan during gelation.

BACKGROUND: Whey protein concentrate (WPC)/pullulan (PUL) hydrogel is applied as a microencapsulation wall material to protect probiotics. However, the interactions between WPC and PUL during gelation have not been clarified. In the present study, the effects of PUL concentration and pH on the interactions between WPC and PUL during gelation were evaluated with respect to appearance, zeta-potential, sulfhydryl group amount, surface hydrophobicity and infrared spectroscopy measurements. The rheological properties of WPC/PUL gels were also determined. RESULTS: The results obtained showed that a proper concentration (0.40 g mL-1 ) of PUL could improve the gel by enhancing the strength of hydrogen bonding, electrostatic interactions and exposure of hydrophobic groups, whereas too much PUL inhibited the formation of disulfide bonds. Furthermore, hydrophobic interactions, disulfide bonds and hydrogen bonds were destroyed in varying degrees under an alkaline environment. The rheological results also demonstrated a similar effect of PUL concentration and pH on the storage modulus (G') of WPC/PUL gels. CONCLUSION: When the WPC/PUL gel was formed at PUL concentration of 0.40 g mL-1 and pH 7.0, the interaction between WPC and PUL could be enhanced, which is beneficial for the future application of WPC/PUL gels in the food industry. © 2020 Society of Chemical Industry.

Lactobacillus fermentum KP-3-fermented ginseng ameliorates alcohol-induced liver disease in C57BL/6N mice through the AMPK and MAPK pathways.

Panax ginseng was fermented using Lactobacillus fermentum KP-3, and the levels of the minor ginsenosides were measured. Then, the effect of fermented ginseng on alcohol-induced liver injury was investigated. C57BL/6N mice were randomly assigned to 4 groups: pair fed (PF), alcohol fed (AF), alcohol with non-fermented ginseng (AF + NFG) and alcohol with fermented ginseng (AF + FG) groups. After treatment for 8 weeks, fermented ginseng intervention significantly reduced the levels of serum ALT, AST, LPS, TG and TC compared with the AF group. The western-blotting results showed that fermented ginseng activated the adenosine-monophosphate-activated protein kinase (AMPK) pathway to inhibit de novo lipogenesis in the liver and inhibited phosphorylation of p38 through the mitogen-activated protein kinase (MAPK) pathway to alleviate hepatic inflammation, and these effects were superior than those of non-fermented ginseng. Furthermore, fermented ginseng reduced alcohol-induced liver oxidative damage by upregulating the levels of antioxidant enzymes. These findings suggested that the L. fermentum KP-3-fermented ginseng product may be used as a potential dietary nutraceutical for alleviating alcoholic liver injury.

Purification and identification of buckwheat hull flavonoids and its comparative evaluation on antioxidant and cytoprotective activity in vitro.

Buckwheat hulls, by-products of buckwheat processing, contain various flavonoids, but the antioxidant capacity and synergy of different flavonoids are unclear. The purpose of this study was to evaluate the antioxidant activity of flavonoid monomers and high-flavonoid component (HBHF) in buckwheat hulls using chemical-based assays and cellular-based assays. Four kinds of flavonoids were identified as rutin, isoorientin, vitexin, and hyperoside from buckwheat hulls. In chemical-based assays, rutin and HBHF showed relatively high free radical scavenging activities and total antioxidant capacities. In cellular-based assays, however, HBHF showed much higher proliferation activity against cell damage than flavonoid monomers when HepG2 cell was oxidatively damaged by H2O2 or high glucose. The cytoprotective activities of flavonoid monomers and HBHF were closely associated with reducing levels of reactive oxygen species (ROS) and malondialdehyde (MDA) or increasing catalase (CAT) activity. In conclusion, buckwheat hull flavonoids are the favorable application candidates for natural antioxidants.

Preparation and characterization of a novel porous whey protein concentrate/pullulan gel induced by heating for Cu2+ absorption.

Whey protein concentrate (WPC) and pullulan (PUL) were used to prepare a hydrogel (WPC/PUL) as a novel Cu2+ adsorbent. The scanning electron microscopy, rheology, zeta-potential, sulfhydryl groups, surface hydrophobicity, infrared spectroscopy and thermal gravimetric analysis measurements were used to characterize WPC/PUL. The results showed the mechanism of gel formation may depend on the combination of electrostatic interaction, disulfide bond, hydrophobic interaction and hydrogen bond. The drying kinetic test was taken, and the drying process of WPC/PUL followed Page Model and the activation energy was 56.73 kJ/mol. Furthermore, WPC/PUL was used as a Cu2+ adsorbent and the absorption can reach more than 98% of the equilibrium adsorption (Qe) after shaking in Cu2+ solution for 10 min and Qe based on the pseudo-second-order kinetic model was 81.66 mg/g. Because the materials were safe and non-toxic, WPC/PUL could be used as a Cu2+ adsorbent during the food industry production process in the future.

Lactobacillus rhamnosus Granules Dose-Dependently Balance Intestinal Microbiome Disorders and Ameliorate Chronic Alcohol-Induced Liver Injury.

As the functions of Lactobacilli become better understood, there are increasing numbers of applications for Lactobacillus products. Previously, we have demonstrated that Lactobacillus rhamnosus GG (LGG) can prevent alcoholic liver injury. LGG granules were produced by fluid bed granulation with a media composed of starch, skimmed milk powder, whey powder, microcrystalline cellulose and maltose, and LGG fermented liquid that comprised 30-50% of the total weight. We found LGG granules dose-dependently protected against chronic alcoholic liver disease. When alcohol was consumed for 8 weeks with LGG treatment during the last 2 weeks, we demonstrated that the dose dependence of LGG granules can improve alcohol-induced liver injury through decreasing the levels of lipopolysaccharide and tumor necrosis factor-α in serum and prevent liver steatosis by suppressing triglyceride, free fatty acid, and malondialdehyde production in liver. Alcohol feeding caused a decline in the number of both Lactobacillus and Bifidobacterium, with a proportional increase in the number of Clostridium perfringens in ileum, and expansion of the Gram-negative bacteria Proteobacteria, Campylobacterales, and Helicobacter in cecum. However, LGG granule treatment restored the content of these microorganisms. In conclusion, LGG granule supplementation can improve the intestinal microbiota, reduce the number of gram-negative bacteria, and ameliorate alcoholic liver injury.

Fermented ginseng improved alcohol liver injury in association with changes in the gut microbiota of mice.

The interactions among the liver, intestine and immune system play an important role in alcoholic liver injury. In this study, C57BL/6N mice with alcoholic injury were treated with unfermented and Lactobacillus fermentum KP-3-fermented ginseng. The indicators of hepatic steatosis, inflammation and injury were evaluated. The number of beneficial and harmful bacteria in the mice ileum and colon was counted by a traditional method; moreover, the diversity analysis of the cecum flora was performed. The alcohol exposure increased the levels of ALT, AST, TNF-α and IL-6 inflammatory factors and liver steatosis. In addition, the alcohol-fed miceexhibited a lower number of Lactobacilli and Bifidobacteria in the ileum and colon; the cecum flora diversity in the mice showed that alcohol obviously enhanced the abundance of the unclassified S24-7 of the Bacteroidetes phylum and the Proteobacteria genus of the Sutterella phylum and reduced the abundance of short-chain fatty acid-producing bacteria such as Akkermansia in the Verrucomicrobia phylum and those belonging to the Allobaculum genus, the Ruminococcus genus, and the Adlercreutzia genus in the Actinobacteria phylum. All these changes were improved by fermented ginseng. Conclusively, fermented ginseng could alleviate the alcoholic liver injury and disorder of the intestine by adjusting the intestinal flora.