Effect of hydrocolloids on starch digestion: A review.

Rapidly digestible starch can increase postprandial blood sugar rapidly, which can be overcome by hydrocolloids. The paper aims to review the effect of hydrocolloids on starch digestion. Hydrocolloids used to reduce starch digestibility are mostly polysaccharides like xanthan gum, pectin, ß-glucan, and konjac glucomannan. Their effectiveness is related to their source and structure, mixing mode of hydrocolloid/starch, physical treatment, and starch processing. The mechanisms of hydrocolloid action include increased system viscosity, inhibition of enzymatic activity, and reduced starch accessibility to enzymes. Reduced starch accessibility to enzymes involves physical barrier and structural orderliness. In the future, physical treatments and intensity used for stabilizing hydrocolloid/starch complex, risks associated with different doses of hydrocolloids, and the development of related clinical trials should be focused on. Besides, investigating the effect of hydrocolloids on starch should be conducted in the context of practical commercial applications rather than limited to the laboratory level.

The substitution sites of hydroxyl and galloyl groups determine the inhibitory activity of human pancreatic α-amylase in twelve tea polyphenol monomers.

Tea polyphenols have been reported as potential α-amylase inhibitors. However, the quantitative structure-activity relationship (QSAR) between tea polyphenols and human pancreas α-amylase (HPA) is not well understood. Herein, the inhibitory effect of twelve tea polyphenol monomers on HPA was investigated in terms of inhibitory activity, as well as QSAR analysis and interaction mechanism. The results revealed that the HPA inhibitory activity of theaflavins (TFs), especially theaflavin-3'-gallate (TF-3'-G, IC50: 0.313 mg/mL), was much stronger than that of catechins (IC50: 18.387-458.932 mg/mL). The QSAR analysis demonstrated that the determinant for the inhibitory activity of HPA was not the number of hydroxyl and galloyl groups in tea polyphenol monomers, while the substitution sites of these groups potentially might play a more important role in modulating the inhibitory activity. The inhibition kinetics and molecular docking revealed that TF-3'-G as a mixed-type inhibitor had the lowest inhibition constant and bound to the active sites of HPA with the lowest binding energy (-7.74 kcal/mol). These findings could provide valuable insights into the structures-activity relationships between tea polyphenols and the HPA inhibitors.

Effects of different gelatinization degrees of starch in potato flour on the quality of steamed bread.

The effect of four kinds of potato flour with different gelatinization degrees on the quality of steam bread was investigated in the present study. Results showed that medium-well flour (MWF) and potato flakes (PF) steamed bread, particularly MWF steamed bread, possessed the desired product properties liked by consumers. The MWF steamed bread had the highest appearance score (42.78) and total sensory evaluation score (81.60), and the PF steamed bread exhibited the highest specific volume (1.84 mL/g) and taste score (43.05). An increase in the degree of potato flour gelatinization led to an increase in dough gas retention coefficient from 80.20 mL/100 mL to 85.17 mL/100 mL and a more uniform and dense dough microstructure. During dough preparation, the increased gelatinization degree of potato flours enhanced the hydroscopicity competition between potato starch and gluten, resulting in a flocculent gluten network and increased potato starch volume during steaming. During steaming, steamed bread with higher gelatinization degree of potato flour formed a homogenous and dense starch gel-gluten double network, making them softer with more uniform gas cells and larger specific volume. Thus, this study provides a perspective of the effect of starch gelatinization on steamed bread quality.

Impact of celluloses and pectins restrictions on gluten development and water distribution in potato-wheat flour dough.

The addition of potato to wheat flour extends the nutritional values of bread. However, the adverse effects mediated by high dietary fiber in potato flour could affect the formation of gluten matrix. The water dynamics and distribution determined by the Low field nuclear magnetic resonance (LF-NMR) demonstrated a competitive water binding of dietary fiber, resulting in the partial dehydration and conformational changes of gluten protein complexes. Besides, the microstructure of the dough characterized by Scanning electron microscope (SEM) suggested that the insoluble cellulose could block the continuity of gluten from the spatial position, thereby negative affecting the mechanical properties of the dough. In our study, addition of cellulase and/or pectinase apparently mitigated the gluten aggregation and dehydration, contributing to the formation and the continuity of the three-dimensional gluten network. As a consequence, the specific volume of the bread was increased by 40.2%, and the hardness was reduced by 64.48%.

Glycyrrhizin Prevents Hemorrhagic Transformation and Improves Neurological Outcome in Ischemic Stroke with Delayed Thrombolysis Through Targeting Peroxynitrite-Mediated HMGB1 Signaling.

Peroxynitrite (ONOO-) and high mobility group box 1 protein (HMGB1) are important cytotoxic factors contributing to cerebral ischemia-reperfusion injury. However, the roles of ONOO- in mediating HMGB1 expression and its impacts on hemorrhagic transformation (HT) in ischemic brain injury with delayed t-PA treatment remain unclear. In the present study, we tested the hypothesis that ONOO- could directly mediate the activation and release of HMGB1 in ischemic brains with delayed t-PA treatment. With clinical studies, we found that plasma nitrotyrosine (NT, a surrogate marker of ONOO-) was positively correlated with HMGB1 level in acute ischemic stroke patients. Hemorrhagic transformation and t-PA-treated ischemic stroke patients had increased levels of nitrotyrosine and HMGB1 in plasma. In animal experiments, we found that FeTmPyP, a representative ONOO- decomposition catalyst (PDC), significantly reduced the expression of HMGB1 and its receptor TLR2, and inhibited MMP-9 activation, preserved collagen IV and tight junction claudin-5 in ischemic rat brains with delayed t-PA treatment. ONOO- donor SIN-1 directly induced expression of HMGB1 and its receptor TLR2 in naive rat brains in vivo and induced HMGB1 in brain microvascular endothelial b.End3 cells in vitro. Those results suggest that ONOO- could activate HMGB1/TLR2/MMP-9 signaling. We then addressed whether glycyrrhizin, a natural HMGB1 inhibitor, could inhibit ONOO- production and the antioxidant properties of glycyrrhizin contribute to the inhibition of HMGB1 and the neuroprotective effects on attenuating hemorrhagic transformation in ischemic stroke with delayed t-PA treatment. Glycyrrhizin treatment downregulated the expressions of NADPH oxidase p47 phox and p67 phox and iNOS, inhibited superoxide and ONOO- production, reduced the expression of HMGB1, TLR2, MMP-9, preserved type IV collagen and claudin-5 in ischemic brains. Furthermore, glycyrrhizin significantly decreased the mortality rate, attenuated hemorrhagic transformation, brain swelling, blood-brain barrier damage, neuronal apoptosis, and improved neurological outcomes in the ischemic stroke rat model with delayed t-PA treatment. In conclusion, peroxynitrite-mediated HMGB1/TLR2 signaling contributes to hemorrhagic transformation, and glycyrrhizin could be a potential adjuvant therapy to attenuate hemorrhagic transformation, possibly through inhibiting the ONOO-/HMGB1/TLR2 signaling cascades.

Study on rapid drying and spoilage prevention of potato pulp using solid-state fermentation with Aspergillus aculeatus.

Effects of solid-state fermentation on rapid drying and spoilage prevention of potato pulp were evaluated. Pectin hydrolyzing and antibacterial ability of pectinase-secreting Aspergillus aculeatus and Bacillus subtilis were compared. A. aculeatus grew better in potato pulp, with highest pectinase yield of 342.71 ±â€¯5.09 U/mL and rapid pH reduction to 3.76 ±â€¯0.01. Next generation sequencing showed that the abundance of genera Candida and Enterobacter, which probably caused undesirable fermentation and spoilage, were significantly reduced after inoculation with A. aculeatus. In addition, fermentation with A. aculeatus significantly reduced water holding capacity from 16.63 ±â€¯0.36 g/g to 7.78 ±â€¯0.12 g/g, which resulted in lower viscosity and water binding capacity, and concomitantly significantly decreased moisture content from 76.05 ±â€¯0.24% to 12.95 ±â€¯0.19% after filtration and airflow drying. These results suggested that solid-state fermentation might be a promising technology for efficient processing and utilization of potato pulp.

Combinatorial effect of fermentation and drying on the relationship between the structure and expansion properties of tapioca starch and potato starch.

Naturally fermented and sundried tapioca starch is reportedly the traditional material for polvilho azedo and the primary ingredients of gluten-free food items in Brazil. This study aimed to investigate starch structure and expansion rate, high rate is acclaimed in baking application, changes of tapioca starch and potato starch during combinatorial fermentation and drying. The rate of expansion changed from 3.37 mL/g in native tapioca starch to 3.71 mL/g in fermented oven-dried tapioca starch and 6.97 mL/g in fermented sun-dried tapioca starch, while potato starch sample displayed lesser expansion on all treatments. Rapid viscosity analysis, size-exclusion chromatography, X-ray diffraction (XRD), and attenuated total reflectance Fourier transform infrared (ATR-FTIR) and electron paramagnetic resonance spectrometry (EPR) were performed to determine the structure and investigate its relationship with the expansion rate. Fermentation attacked amorphous area and cleaved glycosidic bonds. Sunlight exposure facilitated complex interactions, and crosslinking increased the molecular weight distribution (MWD) in fermented sun-dried potato starch and led to depolymerization in tapioca starch. EPR revealed an initial free radical distribution in both starches, and our results show that intensity changes in tapioca starch are essential for a high expansion capacity.

Characterization of physicochemical properties of cellulose from potato pulp and their effects on enzymatic hydrolysis by cellulase.

In this work, cellulose was extracted from potato pulp, a low-efficiently utilized by-product from potato starch industry, by a combined alkali and sodium sulfite treatment. Its physicochemical properties were characterized and compared with cellulose from corn stalk. The yield and purity of cellulose from potato pulp were determined to be 24.74% and 81.34% respectively. Cellulose from potato pulp had more loosened and porous structure, lower crystallinity index and larger specific surface area (SSA) compared with cellulose from corn stalk. It also provided the highest accessibility to cellulase (5.7 mg protein/g glucan) and had the highest enzymatic digestibility (with glucose yield of 88.46%). Maximum adsorption capacity (Wmax) and equilibrium constant (K) were obtained by fitting the adsorption data with the Langmuir adsorption isotherm, suggesting that cellulose from potato pulp had the highest cellulase adsorption efficiency. The data further indicated that the presence of non-cellulosic components, especially for pectin, appeared to have a considerable effect on the hydrolysis by cellulase due to non-productive adsorption. State Key Laboratory of Food Science and Technology, Jiangnan University, 1800 Lihu Avenue Wuxi 214122, Jiangsu Province, People's Republic of China.

Enzyme assisted fermentation of potato pulp: An effective way to reduce water holding capacity and improve drying efficiency.

The effects of an enzyme-assisted fermentation technique on the water holding capacity (WHC) and drying characteristics of potato pulp were investigated. Potato pulp was fermented with Lactobacillus plantarum to increase the content of organic acids, reduce the pH of the pulp and assist in enhancing the enzymatic hydrolysis. Removal of pectin and cellulose reduced the WHC of potato pulp from 16.84 to 6.83 and 9.64 g/g, respectively. Drying characteristics were determined using the air-drying process, which indicated that pectinase-assisted fermentation could remove pectin from potato pulp and shorten the air-drying time from 240 to 140 min, while cellulase had an opposite effect on the drying rate. This result was also confirmed by low field nuclear magnetic resonance (LF-NMR), which showed more mobile water and less bonded water in pectin-removed potato pulp samples.

Baicalin Attenuates Blood-Brain Barrier Disruption and Hemorrhagic Transformation and Improves Neurological Outcome in Ischemic Stroke Rats with Delayed t-PA Treatment: Involvement of ONOO--MMP-9 Pathway.

Tissue plasminogen activator (t-PA) has a restrictive therapeutic window within 4.5 h after ischemic stroke with the risk of hemorrhagic transformation (HT) and neurotoxicity when it is used beyond the time window. In the present study, we tested the hypothesis that baicalin, an active compound of medicinal plant, could attenuate HT in cerebral ischemia stroke with delayed t-PA treatment. Male Sprague-Dawley rats were subjected to middle cerebral artery occlusion (MCAO) for 4.5 h and then continuously received t-PA infusion (10 mg/kg) for 0.5 h and followed by 19-h reperfusion. Baicalin (50, 100, 150 mg/kg) was administrated via femoral vein at 4.5 h after MCAO cerebral ischemia. Delayed t-PA infusion significantly increased the mortality rate, induced HT, blood-brain barrier (BBB) damage, and apoptotic cell death in the ischemic brains and exacerbated neurological outcomes in cerebral ischemia-reperfusion rats at 24 h after MCAO cerebral ischemia. Co-treatment of baicalin significantly reduced the mortality rates, ameliorated the t-PA-mediated BBB disruption and HT. Furthermore, baicalin showed to directly scavenge peroxynitrite and inhibit MMP-9 expression and activity in the ischemic brains with the delayed t-PA treatment. Baicalin had no effect on the t-PA fibrinolytic function indicated by t-PA activity assay. Taken together, baicalin could attenuate t-PA-mediated HT and improve the outcomes of ischemic stroke treatment possibly via inhibiting peroxynitrite-mediated MMP-9 activation.

Characterisation of physicochemical and functional properties of soluble dietary fibre from potato pulp obtained by enzyme-assisted extraction.

In this study, enzyme-assisted methodology was applied with the aim to optimise the efficiency of soluble dietary fibre (SDF) extraction from potato pulp. The yields of SDF pretreated by cellulase, xylanase, and a cellulase/xylanase mixture were 31.9% (w/w), 25.7% (w/w), and 39.7% (w/w) respectively. When comparing single enzyme pretreatment with combined enzymatic treatment, we observed differences in properties related to molecular weight and viscosity. SDF obtained by xylanase pretreatment rendered better results for glucose dialysis retardation index (32.98%, w/w), amylase inhibitory effect (56.2%), and pancreatic lipase inhibitory activity (55.33%), while combined enzymatic pretreatment exhibited better effect in properties related to exposure of functional groups and specific surface area, including sodium cholate binding capacity (72.2%) and hydroxyl radical scavenging activity (87.57%). Our results indicated that enzymatic pretreatment, which could effectively hydrolyse cellulose and hemicellulose components, could not only benefit the yield of SDF, but also enhance its physiological and functional properties.

Characterization of selenium-enriched mycelia of Catathelasma ventricosum and their antihyperglycemic and antioxidant properties.

This is the first report concerning the selenium enrichment of Catathelasma ventricosum mycelia. The selenium-containing proteins present in selenium-enriched mycelia (Se-MC) were identified using size-exclusion chromatography-inductively coupled plasma-mass spectrometry (SEC-ICP-MS). The selenium-containing amino acids liberated by hydrolysis of these proteins were identified using anion exchange-ICP-MS. Se-MC was found to contain selenoproteins with molecular weights ranging from 1.7 to 60.5 kDa. The main selenium-containing amino acids within them were selenomethionine and selenocysteine. Furthermore, Se-MC possessed excellent antihyperglycemic and antioxidant properties. Se-MC normalized biochemical parameters like insulin level, blood glucose level, body weight, and antioxidant enzyme activity in streptozocin-induced diabetic mice. It also inhibited the α-amylase and α-glucosidase activities present in in vitro gastric and intestinal models. In conclusion, Se-MC has the potential to serve as a dietary supplement of selenium, an antioxidant, or an ingredient for the formulation of nutraceuticals.

Antidiabetic activity of mycelia selenium-polysaccharide from Catathelasma ventricosum in STZ-induced diabetic mice.

Se-polysaccharide from Catathelasma ventricosum (SPC-2) was purified by DEAE-52 and Sephadex G-100 column chromatography. The average size of SPC-2 was 1.6×10(5) Da, and it was mainly composed of glucose (87.4%) with the conformation of ß-pyran ring. The branched structure of SPC-2 was proved intuitively by atomic force microscope (AFM). The antidiabetic potential of SPC-2 was tested in STZ-induced diabetic mice. After STZ-induced diabetic mice being administered of SPC-2 for 30 days, SPC-2 treatment significantly reduced the levels of malondialdehyde (MDA) and low-density lipoprotein cholesterol (LDL-C) that were increased by the STZ treatment. Further, the SPC-2 treatment led to increased activity of antioxidant enzymes in liver and kidney and high-density lipoprotein cholesterol (HDL-C) that were decreased by the STZ. The results of histopathology also showed SPC-2 protected tissues (pancreas, liver and kidney) against peroxidation damage and maintained tissue integrity.