Huijuan Zhang

Optimisation of ultrasound-assisted enzymatic extraction of arabinoxylan from wheat bran

Arabinoxylan, the major dietary fibre component of wheat bran, is important from both technological and nutritional points of view. In this study, ultrasound-assisted enzymatic extraction technology was first employed to extract arabinoxylan from wheat bran. The process for extraction of arabinoxylan was optimised using response surface methodology, employing a five-level, five-variable central composite rotatable design. The optimum extraction conditions were as follows: raw material concentration, 50g/l, enzyme dose, 4.5g/l, extraction temperature, 50°C; extraction time, 70min; and ultrasonic power, 180W. Under the above mentioned conditions, the experimental yield was 142.6±0.17mg/g of wheat bran, which is well matched with the predictive yield. Ultrasound increased the efficiency of enzymatic treatment with higher extraction yield.

Application of an optosensing chip based on molecularly imprinted polymer coated quantum dots for the highly selective and sensitive determination of sesamol in sesame oils.

A novel optosensing chip was constructed by anchoring the fluorescence sensing material layer based on molecularly imprinted polymer (MIP) coated CdSe/ZnS quantum dots (QDs) on a chip for highly selective and sensitive optosensing of sesamol in sesame oil. Many factors that affected the performance of the optosensing chip based on MIP-coated QDs are discussed. Under optimized conditions, the relative fluorescence intensity of the optosensing chip decreased linearly (r(2) > 0.99) with increasing sesamol concentration in the range from 2.4 × 10(-6) to 1.2 × 10(-3) mol L(-1) with a detection limit of 7.2 × 10(-8) mol L(-1). The relative standard deviation for five replicate detections of 4.8 × 10(-4) mol L(-1) sesamol was 2.2%. Recoveries of 94.8-102.3% were achieved by direct detection when the optosensing chip was used for the selective detection of sesamol in sesame oil. Practically, the optosensing approach showed high sensitivity, good selectivity, and excellent reproducibility for the detection of sesamol in real oil samples.

Triple-channel comparative analysis of volatile flavour composition in raw whole and skim milk via electronic nose, GC-MS and GC-O

A novel triple-channel comparative analysis of volatile composition in raw whole and skim milk (RWM and RSM) was developed via an electronic nose (E-Nose), headspace solid-phase micro-extraction (HS-SPME) coupled with gas chromatography-mass spectrometry (GC-MS), and gas chromatography-olfactometry (GC-O). Volatile flavour compounds from RWM and RSM caused the differences in mouthfeel characteristics by the human sensors, and also affected consumer preference. Solid state sensor technology, an E-Nose, was applied to distinguish the differences in volatiles between RWM and RSM. Headspace volatiles adsorbed by HS-SPME fiber (CAR/PDMS) were detected by GC-MS. Aroma compounds were identified by GC-O. Nine and three compounds were found to be aroma-active compounds from RWM and RSM, respectively. Octanoic acid, butanoic acid, and 3-hydroxy-2-butanone were found to be the most important aroma-active compounds in RWM, while the most important aroma-active compound of RSM was octanoic acid.

Amylopectin is the anti-fatigue ingredient in glutinous rice

The anti-fatigue activities of glutinous rice (GR) and GR amylopectin (GRA) were investigated in mice by determining tissue glycogen, blood lactate dehydrogenase (LDH), and blood urea nitrogen (BUN) after the weight loaded forced swim test (WFST). GR and GRA were given by gavage at various doses of GR (7.5, 15, 30 g/kg body weight) and GRA (3.8, 7.5, 15 g/kg body weight) every day for 7 days, respectively. The results indicated that the hepatic glycogen levels significantly (P<0.05) increased 26-44% and 35-60% and the muscle glycogen levels significantly (P<0.05) increased 36-100% and 67-133% in GR and GRA treatment groups, compared with the negative control group. The GRA treatment groups also had significantly (P<0.05) higher (9.1-20.3%) blood LDH levels. Meanwhile, the blood LDH activities in GR and GRA treatment groups had a significantly positive correlation with the hepatic glycogen levels (r=0.978, P<0.01). Moreover, except of the low-dose GR (7.5 g/kg body weight) supplemented group, mice in all other treatment groups had significantly (P<0.05) lower (13-23%) BUN levels. Compared with the GR treatment groups, GRA treatment groups had similar or even higher anti-fatigue activities, which demonstrated that GRA might play the most important role on the anti-fatigue activities for GR.

Peptides Derived from Oats Improve Insulin Sensitivity and Lower Blood Glucose in Streptozotocin-Induced Diabetic Mice

Background: Oat, as a “third staple food” following rice and wheat in China, has been widely utilized due to the hypoglycemic activities of oat β-glucan. Oat also contains 15-20% protein, which consists of balanced amino acid profile devoid of anti-nutritional factors. Peptides from albumin, whey protein and other foods have been proposed to have hypoglycemic activities while the hypoglycemic activities of oat peptides have not been reported to our knowledge. Results: The hypoglycemic activities and underlying mechanisms of alcalase2.4 L oat hydrolysates purified by ultrafiltration were investigated in streptozotocininduced diabetic mice using metformin as the positive control. The hypoglycemic activities of oral administration of oat peptides (0.25, 0.5 and 1.0 g kg bw-1) were in a dose-depended manner. In the highest does treatment group, mice had the significantly (P < 0.05) lower total food intake and fasting blood glucose (FBG) and the higher food efficiency, serum fasting insulin (Fins), insulin activity index (IAI), and hepatic glycogen content compared with the 0.25 and 0.5 g kg bw-1 treatment groups. Moreover, the FBG concentrations positively correlated with total food intake (r =0.994, p < 0.01) and negatively correlated with Fins concentrations (r =- 0.979, P < 0.01), IAI (r = -0.942, P < 0.01), and hepatic glycogen contents (r = -0.952, P < 0.01). Conclusion: The results indicated that the underlying mechanisms of the oat peptides’ antidiabetic action could be linked to more than one mechanism, such as controlling the food intake, stimulating the insulin secretion and insulin sensitizing, and elevating the glycogenesis.

Wheat bran feruloyl oligosaccharides modulate the phase II detoxifying/antioxidant enzymes via Nrf2 signaling

The antioxidant activities of wheat bran feruloyl oligosaccharides (FOs) were determined in rats by determining the activities and mRNA expression levels of phase II detoxifying/antioxidant enzymes such as superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GSH-Px), and heme oxygenase-1 (HO-1) in rat organs. FOs was given by gavage at doses of 0.25, 0.5, and 0.75 mmol/kg body weight every day for 15 days. Compared with the control group, the activities of SOD, CAT, and GSH-Px in FOs treatment groups significantly (P<0.05) increased in heart, liver, and kidney. All the FOs treatment also significantly (P<0.05) increased the glutathione (GSH) contents in heart (28-58%), liver (32-71%), and kidney (31-73%) compared with the control. FOs up regulated the mRNA expression levels of SOD, CAT, and HO-1 in organs. Moreover, the immunoblot analysis revealed increased nuclear factor-E2-related factor (Nrf2) protein expression levels in organs and there were positive correlations between the mRNA expression of phase II detoxifying/antioxidant enzymes and the expressions of Nrf2 protein, which demonstrated FOs treatment could modulate the detoxifying/antioxidant enzymes via Nrf2 signaling.

Whole cereal grains and potential health effects: Involvement of the gut microbiota

The intakes of whole cereal grains (WCGs) have long been linked to decreased risks of metabolic syndromes (MetS) and several chronic diseases. Owing to the complex range of components of cereals, which may show synergistic activities to mediate these protective effects, the mechanisms by which the benefits of whole cereals arise are not fully understood. The gut microbiota has recently become a new focus of research at the intersection of diet and metabolic health. Moreover, cereals contain various ingredients known as microbiota-accessible substrates that resist digestion in the upper gastrointestinal tract, including resistant starch and non-starch polysaccharides such as β-glucan and arabinoxylans, making them an important fuel for the microbiota. Thus, WCGs may manipulate the ecophysiology of gut microbiota. In this review, the scientific evidence supporting the hypothesis that WCGs prevent MetS by modulating gut microbiota composition and functions are discussed, with focuses on cereal intake-related mechanisms by which gut microbiota contributes to human health and scientific evidences for the effects of WCGs on modulating gut microbiota. Once strong support for the association among WCGs, gut microbiota and host metabolic health can be demonstrated, particular cereals, their processing technologies, or cereal-based foods might be better utilized to prevent and possibly even treat metabolic disease.

Evaluation of the Cellular and Animal Models for the Study of Antioxidant Activity: A Review

The mechanisms of antioxidant activities of phytochemicals are highly complex, so various methods to study them have been developed. However, the diverse available methods show inconsistent results. Different stressors, cell models, and animal models have been used to evaluate the antioxidant properties of phytochemicals. However, the literature still lacks a summary of the effects of different stressors, cell models, and animal models on the evaluation of antioxidant activities. Therefore, the mechanisms of action of different oxidative stimuli and the characteristics of the available cell models and animal models are summarized in this review.

Home‐based preparation approaches altered the availability of health beneficial components from carrot and blueberry

Abstract This study investigated the effects of different home food preparation methods on availability of total phenolic contents (TPC) and radical scavenging components, as well as the selected health beneficial compounds from fresh blueberry and carrot. High performance liquid chromatography (HPLC) analysis revealed that ground carrots using blenders released significantly greater amount of β‐carotene than their chopped counterpart, and blueberry samples prepared with different commercial blenders/grinders released different levels of cyaniding‐3‐O‐glucoside and malvidin‐3‐O‐glucoside. Furthermore, microwaving was able to significantly alter the releasable amounts of cyaniding‐3‐O‐glucoside and malvidin‐3‐O‐glucoside from blueberries. In addition, carrots and blueberries processed using different blenders and chopping with or without microwaving differed in their available levels of TPC, and radical scavenging components against DPPH •, oxygen radicals and HO •, as well as their potential anti‐inflammatory activities. Taking together, these results indicated that home food preparation approaches may alter the availability of health components from carrots and blueberries. The results also suggested that the influence may depend on the fruit and vegetable type, but not the price of blenders/grinders.

Whole Tibetan Hull‐Less Barley Exhibit Stronger Effect on Promoting Growth of Genus Bifidobacterium than Refined Barley In Vitro

The gut microbiota has recently become a new route for research at the intersection of diet and human health. The aim of this study was to investigate whether whole Tibetan hull-less barley (WHB) and refined Tibetan hull-less barley (RHB) caused differentiation of the fecal microbiota in vitro. The microbiota-accessible ingredients in the 2 barley samples were studied using an in vitro enzymatic digestion procedure. After in vitro digestion, insoluble dietary fiber, phenolic compounds, proteins, and β-glucans were 93.2%, 103.4%. 18.8%, and 10.2% higher provided by WHB flour as compared with RHB flour based on the same mass amount. However, due to the significantly higher content of insoluble dietary fiber, WHB digesta had lower percentage contents of fast fermentable substrates including dietary fiber and starch as compared with RHB digesta. The results of Next-generation sequencing of the bacterial 16SrRNA gene showed that both WHB and RHB fermentation had significantly promoted the growth of Bifidobacterium and inhibited the growth of pathogenic bacteria such as Dorea, Escherichia, Oscillopira, and Ruminococcus. Moreover, in response to WHB fermentation, the relative abundance of Bifidobacterium increased by 78.5% and 92.8% as compared with RHB and fructo-oligosaccharides (FOs). Both WHB and RHB are good sources of fermentable dietary fiber with the ability to yield high concentration of short chain fatty acids (SCFAs) as compared to FOs. However, the higher fraction of soluble fiber in RHB digesta increase higher amounts of SCFA compared with WHB digesta. Our findings shed light on the complex interactions of whole cereals with gut microbiota and the possible impact on host health. PRACTICAL APPLICATION Until now, only few reports have regarded the impact of in vitro digestion in components of whole grain with complex food matrix. Moreover, our findings shed light on the complex interactions of whole cereals with gut microbiota and the possible impact on host health.