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- Author or Editor: H. Sun x
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The objective of this work was to research the antibacterial effects of orange pigment, which was separated from Monascus pigments, against Staphylococcus aureus. The increase of the diameter of inhibition zone treated with orange pigment indicated that orange pigment had remarkable antibacterial activities against S. aureus. Orange pigment (10 mg ml−1) had a strong destructive effect on the membrane and structure of S. aureus by the analysis of scanning electron microscopy as well as transmission electron microscopy. Sodium dodecyl sulphate-polyacrylamide gel electrophoresis (SDS-PAGE) further demonstrated that the cell membrane was seriously damaged by orange pigment, which resulted in the leakage of protein from S. aureus cells. A significant decrease in the synthesis of DNA was also seen in S. aureus cells exposed to 10 mg ml−1 orange pigment. All in all, orange pigment showed excellent antibacterial effects against S. aureus.
Temperature uniformity and heating rate subjected to radio frequency (RF) heating have major impact on the quality of treated low moisture foods. The objective of this paper was to analyse the influence of electrode distance on the heating behaviour of RF on condition that the sample shape, size, and location between the electrodes were defined. Considering peanut butter (PB) and wheat flour (WF) as sample food, a 3D computer simulation model was developed using COMSOL, which was experimentally validated by a RF machine (27.12 MHz, 6 kW). Specifically, the electrode distances were selected as 84, 89, 93, 99 and 89, 93, 98, 103 (mm) for RF heating of PB and WF, respectively. Results showed that the simulated results and experimental data agreed well; the temperature-time histories of the RF heating of PB and WF were approximate straight lines; both the temperature uniformity index and the heating rate decreased with the increase of the electrode distance; the heating rate had a negative logarithmic linear relationship with the electrode distance, which was independent of the types, geometry shapes and sizes of low moisture foods.
Optimization of extraction ratio (ER) of tree peony seed protein (TPSP) was investigated using response surface methodology (RSM). The second-degree equation for ER of TPSP had high coeffi cient (0.9625) of determination. The probability (P) value of regression model signifi cance was less than 0.001 by analysis of central composite rotatable design. Relationships of ER to pH, liquid/solid ratio, squares of all factors, and cross-product factors (x2x3, x2x4, x3x4) were signifi cant (P<0.05). Whereas, extraction time, temperature, and cross-product terms (x1x2, x1x3, x1x4) were not signifi cant factors (P>0.05). Optimum extraction conditions were 3.42 h, pH 9.50, 50.80 ºC, and 9.54 ml g–1 of liquid/solid ratio with the maximum ER (43.60%) . SDS-PAGE indicated TPSP had mainly four proteins (180, 100, 60, and 35 kDa) with four subunits of 60, 48, 38, and 23 kDa. TPSP had a good amino acid composition with abundant essential amino acids (39.76%) determined by amino acid analysis.
Abstract
In this study, a water-soluble novel polysaccharide called TPS was successfully prepared and isolated from Liubao tea. The optimal extraction conditions resulted in a yield of 10.70% for the crude TPS. The purified TPS exhibited unique physicochemical properties and structural characteristics. It was identified as an acidic polysaccharide with trace binding proteins, with a →4)-α-D-Galp-(1→) residue. The purified TPS had a dense and uneven appearance, potential crystallisation characteristics, and structural stability. Importantly, it demonstrated the ability to inhibit glucose transport in Caco-2 cells by down-regulating the expression of sodium/glucose cotransporter 1 (SGLT1) and glucose transporter 2 (GLUT2), leading to a hypoglycemic effect. These findings highlight the potential of TPS from Liubao tea as a functional food or additive with hypoglycaemic properties.
Abstract
There have been contradicting observations regarding the prebiotic efficacy of feruloylated oligosaccharides (FOs) extracted from different varieties of cereals with varying oligosaccharides and ferulic acid (FA) levels. The present study was performed to determine whether the mass ratio of xylooligosaccharide (XOS) to FA influences their combined effects on faecal FA content, short chain fatty acid (SCFA) output, and gut stress of d-galactose-treated aging rats. The results show that there was no significant difference in the faecal FA levels of rats fed with 5:1 and 10:1 XOS:FA diet, although the FA level in the 5:1-supplemented diet was twice as much as in the 10:1 diet. More utilisation of FA decreased butyric acid and SCFA output in the faeces for diet 5:1 compared with diets 10:1 XOS:FA or XOS alone. Furthermore, compared with 10:1 XOS:FA or XOS alone treatments, the 5:1 XOS:FA diet resulted in increased 1-diphenyl-2-picrylhydrazyl activity and higher ratios of Bifidobacterium or Lactobacillus to Escherichia coli (P < 0.05), while not increasing the number of probiotic Bifidobacterium and Lactobacillus. These findings suggest that under the specific stress level set for this study, the sufficient amount of FA added to XOS (5:1) can stimulate FA utilisation to modify gut redox balance, while reducing faecal SCFA output.
Influence of different maturity stages and treatments of ethephon, exogenous ABA, and fluridone on the ripening and hormone level of ‘Zhonghuashoutao’ peach during development and post-harvest storage were investigated. The accumulation of endogenous ABA appeared at the onset of ripening and peaked at two weeks before harvest. Fruit firmness decreased, while ethylene release and SSC/TA increased sharply after a maximum peak of ABA, which have triggered the initiation of the fruit ripening. The fruits, harvested at 170 d when fruits have ripened and stored at 20 °C, showed an ethylene climacteric peak, and the pulp started softening normally, and the SSC/TA value increased. Compared with them, the immature green fruits harvested at other dates, could not mature normally due to the lack of normal reciprocity between ABA and ethylene. The ethylene release was promoted by the treatment of exogenous ABA and ethephon during ripening until the endogenous ABA reached a maximum value. However, fluridone treatment showed an inhibitory effect. The above-mentioned changes occurred again in the peach fruits after harvest. The results indicated that both ABA and ethylene play important roles in peach ripening, and their action depended on the ripening stage of peach.
Abstract
Conversion of economic microcrystalline cellulose (MCC) into high value-added prebiotic glucans, is not only stimulates utilisation of renewable lignocellulosic biomass, but also provides cheap prebiotics to reduce high incidence of obesity and metabolic syndrome. Herein, glucans (C0.25–C0.50–C1.00) from MCC were prepared by pre-impregnation with dilute sulphuric acid (0.25–0.50–1.00%) and ball-milling treatment for 1 h. NMR spectroscopy and gel-permeation chromatography of the glucan products showed a significant reduction in the degree of polymerisation (DP) and molecular weights (Mw). All prepared glucans improved gut stress evaluated by in vitro digestion and fermentation (young and aging mouse faecal inocula). C1.00 with lower DP and Mw showed better water solubility, earlier peak, and exhibited increased 1-diphenyl-2-picrylhydrazyl activity, higher ratios of Lactobacillus to Escherichia coli, and a higher level of short chain fatty acids better than C0.25 and C0.50 treatment (P < 0.05). Better prebiotic effects were observed in aging mice than in young mice. The highest ratio of Lactobacillus to E. coli was a 2.13-fold increase for aging mice compared to a 1.79-fold increase for young mice, relative to the initial value after C1.00 treatment. The study provides a novel pathway and a new resource for producing glucan.
Abstract
Soluble dietary fibre (SDF) is well recognised for its remarkable effectiveness in promoting human health. This study utilised response surface methodology to evaluate the optimal conditions required to extract SDF (U-SDF) from Lentinula edodes via the ultrasonic-assisted hot-water method, and evaluated the hypolipidemic effects and anti-inflammatory effects of U-SDF. The optimal extraction conditions for U-SDF were ultrasonic power of 182 W, extraction time of 2 h, extraction temperature of 81 °C, and solid-liquid ratio of 1:24 (g mL−1). Under these conditions, the extraction rate of U-SDF reached 8.08%. U-SDF treatment significantly improved liver and kidney indices in diabetic mice, markedly reduced the levels of plasma triglycerides (TG), total cholesterol (TC), low-density lipoprotein-cholesterol (LDL-C), and significantly increased the level of high-density lipoprotein-cholesterol (HDL-C) in a dose-dependent manner. U-SDF also improved adipose tissue injury in diabetic mice, significantly decreased the levels of cytokines interleukin-1β (IL-1β), interleukin-6 (IL-6), and tumour necrosis factor-α (TNF-α), and alleviated inflammation of the abdominal aorta. In conclusion, U-SDF from L. edodes is an excellent source of dietary fibres, which exhibit good hypolipidemic and anti-inflammatory activities, suggesting potential applications as a functional additive in diverse food products.
