Yuehua Wang

Combined effect of ultrasound, heat, and pressure on Escherichia coli O157:H7, polyphenol oxidase activity, and anthocyanins in blueberry (Vaccinium corymbosum) juice

The objective of this study was to evaluate the effect of different treatments-heat treatment (HT), sonication (SC), thermosonication (TS), manosonication (MS), manothermal (MT), and manothermosonication (MTS) on Escherichia coli O157:H7, polyphenol oxidase (PPO), and anthocyanin content in blueberry juice. First, samples were treated at different temperatures (30, 40, 50, 60, 70, and 80°C) and power intensities (280, 420, 560, and 700W) for 10min. Subsequently, samples were treated using combinations of power intensity and mild temperature for 10min. For further study, samples were treated using HT (80°C), TS (40°C, 560W), MT (350MPa, 40°C), MS (560W, 5min/350MPa), or MTS (560W, 5min, 40°C/350MPa, 40°C) for 5, 10, 15, 20min for each treatment, and the results compared between treatments. HT significantly reduced PPO activation (2.05% residual activity after only 5min), and resulted in a 2.00-log reduction in E. coli O157:H7 and an 85.25% retention of anthocyanin. Escherichia coli O157:H7 was slightly inactivated by TS after 5min (0.17-log reduction), while residual PPO activity was 23.36% and anthocyanin retention was 98.48%. However, Escherichia coli O157:H7 was rapidly inactivated by MTS (5.85-log reduction) after 5min, while anthocyanin retention was 97.49% and residual PPO activity dropped to 10.91%. The destruction of E. coli cells as a result of these treatments were confirmed using SEM and TEM. Therefore, a combination of sonication, high pressure, and mild heat allows the safety of blueberry juice to be maintained without compromising the retention of desirable antioxidant compounds.

Modulation of Actinidia arguta fruit ripening by three ethylene biosynthesis inhibitors.

The purpose of this study was to investigate the effect of postharvest application of 1-methylecyclopropene (1-MCP), 1-pentylcyclopropene (1-PentCP) and 1-octylcyclopropene (1-OCP), two structural analogues of 1-MCP, on Actinidia arguta (Siebold et Zucc.) Planch. ex. Miq. Fruit post-harvest ripening and antioxidant activity. The results showed that these two structural analogues, just as 1-MCP, exerted their effect in a concentration-dependent manner. The most effective concentration of 1-MCP, 1-PentCP or 1-OCP treatment was 1.2 μl L(-1), 1.2 μl L(-1) and 0.8 μl L(-1), respectively. But, 0.8 μl L(-1) 1-OCP was found to be more potent in postponing the appearances of respiration rate peak and ethylene production peak, delaying the softening and weight loss, suppressing the activities of ACC synthase (ACS) and ACC oxidase (ACO), maintaining higher glutathione (GSH) content, activities of glutathione reductase (GR) and ascorbate peroxidase (APX), though slightly inferior to 1.2 μl L(-1) 1-MCP.

Effect of 1-pentylcyclopropene on Physiological Responses and Gene Expression of Ethylene Receptors in Post-Harvest Bananas

The aim of this study was to investigate the inhibitory effect of 1-pentylcyclopropene (1-PentCP), a structural analogue of 1-methylcyclopropene (1-MCP), on postharvest ripening and senescence of bananas fruit (Musa acuminata L. AAA group cv. Brazil). The results showed that 1-PentCP was effective in postponing the occurrence time of ethylene production peak and respiration rate peak, delaying the softening and color change, inhibiting the increasing of soluble solids, soluble sugar, and 1-aminocyclopropane-1-carboxylate acid (ACC) content; inhibiting the activities of ACC synthase (ACS) and ACC oxidase (ACO); and suppressing the expression of MaERS1 and MaERF1 in bananas. In addition, 1.2 μL/L 1-PentCP was found to be most effective in delaying ripening and senescence process of bananas by inhibiting the activities of enzymes involved in ethylene biosynthesis and gene expression of ethylene receptors. It is suggested that 1-PentCP could be a promising candidates for practical use as a given ethylene inhibitor applied before the onset of ethylene action.

Preparative Purification of Polyphenols from Aronia melanocarpa (Chokeberry) with Cellular Antioxidant and Antiproliferative Activity

The aim of this study was the purification process of polyphenols from Aronia melanocarpa (chokeberry), and the purification parameters were optimised by adsorption and desorption tests. By comparing adsorption and desorption ability of polyphenols from chokeberry on six kinds of macroporous resin, XAD-7 resin was selected. Experiments prove that the best purification parameters of static adsorption and desorption were sample pH = 4.0 with 4 h of adsorption; and desorption solvent is 95% ethanol (pH = 7.0) with 2 h of desorption. The best dynamic parameters were 9.3 bed volume (BV) of sample loading amount at a feeding flow rate of 2 BV/h, and washing the column with 5.8 BV of water, followed by subsequent elution with an eluent volume of 5.0 mL at an elution flow rate of 2 BV/h. Next the antioxidant and antiproliferative activity of polyphenols from chokeberry, blueberries, haskap berries was studied on HepG2 human liver cancer cells. The results show that polyphenol from chokeberry has a strong antioxidant effect. Taking into account the content of polyphenols in fruit, polyphenols from chokeberry represent a very valuable natural antioxidant source with antiproliferative products.

Chicory inulin ameliorates type 2 diabetes mellitus and suppresses JNK and MAPK pathways in vivo and in vitro

SCOPE Chicory inulin is a naturally occurring fructan that is conducive to glucose and lipid metabolism in patients with diabetes mellitus. This study aims to investigate the mechanism by which chicory inulin improves glucolipid metabolism in diabetic conditions. METHODS AND RESULTS Rats were injected with streptozotocin and fed with high fat diet to induce diabetes, and then administrated with different doses of chicory inulin for 8 weeks. The glycometabolism and lipid metabolism parameters were determined, the activity of insulin receptor substrate (IRS) and mitogen-activated protein kinase (MAPK) pathways were examined by western blot. The effect of chicory inulin on glucose uptake of myoblast and hepatocyte were also measured in vitro. Data were analyzed by students t-test or one-way analysis of variance followed by the Bonferroni post-hoc testing. The results showed that chicory inulin improved glucolipid metabolism, and it activated IRS but suppressed the MAPK pathways in vivo and in vitro. CONCLUSION Our study demonstrates that chicory inulin, as a nutritional supplement, may be beneficial for the patients with type 2 diabetes mellitus, and the metabolism-modulatory effect seems to be related with the inhibition of JNK and P38 MAPK pathways.

Blueberry polyphenols extract as a potential prebiotic with anti-obesity effects on C57BL/6 J mice by modulating the gut microbiota

Polyphenols are known for their various health benefits. Blueberries are dietary sources of polyphenols with reported health benefits. However, the role of blueberry polyphenols in alleviating obesity is not completely understood. This study investigated the potential positive effect of blueberry polyphenol extract (PPE) on high-fat diet (HFD)-induced obesity in C57BL/6 J mice by modulation of the gut microbiota. Four-week-old C57BL/6 J mice were fed a normal-fat diet or HFD with or without PPE or Orlistat for 12 weeks. Mice fed HFD exhibited increased body weight and adipose tissue weight and disordered lipid metabolism. In contrast, PPE inhibited body weight gain and returned lipid metabolism to normal. Furthermore, 16S rRNA gene sequencing of the fecal microbiota suggested that PPE changed the composition of the gut microbiota in C57BL/6 J mice and modulated specific bacteria such as Proteobacteria, Deferribacteres, Actinobacteria, Bifidobacterium, Desulfovibrio, Adlercreutzia, Helicobacter, Flexispira, and Prevotella. Orlistat also improved obesity and metabolic alterations of HFD mice and modulated the composition of the gut microbiota. Our findings suggest that PPE, as a potential prebiotic agent, influences the gut microbiota to positively affect HFD-induced obesity in C57BL/6 J mice.

Comparative analysis of the polyphenols profiles and the antioxidant and cytotoxicity properties of various blue honeysuckle varieties

Abstract The polyphenol profile, antioxidant activity (particularly peroxyl radical-scavenging capacity (PSC) and cellular antioxidant activity (CAA)) and cytotoxicity of extracts from seven varieties of blue honeysuckle were compared in this study. Moreover, an analysis of correlations between individual polyphenol profiles and antioxidant activities was also conducted. Seventeen components were found in the investigated blue honeysuckle extracts, with anthocyanins being the prominent bioactive components among polyphenols. Fruit peel contained higher concentrations of individual anthocyanins compared to the fruit pulp. Beilei blue honeysuckle had the highest antioxidant activity. Correlation analysis showed that antioxidant activity values were highly associated with cyanidin-3-glucoside levels. Blue honeysuckle extracts were not cytotoxic over the range of doses tested. Among the varieties analyzed, Beilei possessed the highest antioxidant properties and was found to be the most appropriate source of natural antioxidants.