Effects of processing on the phenolic contents,antioxidant activity and volatile profile of wheat bran tea

Wheat bran is a major milling by-product with significant nutritional importance. This study investigated the influence of processing on the antioxidant activity and volatile profile of wheat bran tea. The processing protocol involved two different pretreatments: soaking and cellulase treatment, followed by steaming and roasting. The results indicated that total phenolic content and antioxidant activity were reduced post both pretreatments, but increased after steaming, and dramatically increased after roasting. The cellulase-roasted samples had significantly higher antioxidant activity compared to soak-roasted samples. A total of forty key volatile compounds were identified in the wheat bran tea. The total volatile compounds were significantly increased by both soaking and cellulase treatments and steaming, but reduced by roasting. Compared to soaking pretreatment, cellulase pretreated samples had significantly higher total volatile compounds at each processing step. This study offers a practical method in processing of wheat bran into novel grain tea products.     

发酵条件对小米酸粥中多酚含量的影响及其主要组分研究

探究小米酸粥发酵过程中发酵时间及发酵温度对多酚含量的影响，并对比小米酸粥与小米粥中主要成分差异。结果显示，小米酸粥中多酚含量随时间增加而增多，在20 h处达到最大值。在32 ℃的发酵温度下，小米酸粥中多酚含量最多。与小米粥相比，小米酸粥降低了煮制导致的多酚损耗，且酸粥中多酚抗氧化活性较小米粥高。小米酸粥中蛋白、脂肪含量均较高，分别达到13.5 mg/100 g及6.2 mg/100 g，而淀粉含量较低为53.4 mg/100 g，与小米粥相比降低了8.7 mg/100 g。此外，小米酸粥发酵可增加不可溶性膳食纤维含量及上清液中的游离色氨酸含量。     

Preparation and use of apple skin polyphenol extracts in milk: enhancement of the viability and adhesion of probiotic Lactobacillus acidophilus (ATCC 1643) bacteria

This study explored the feasibility of using apple skin as a source for generating antioxidant extracts, that is ethanolic or aqueous apple skin polyphenol extract (ASPE) and examined the effects of such ASPEs and six purified polyphenols (PPs), that is rutin, epicatechin, phlorizin, cholorogenic acid, quercetin and p‐coumaric acid on the viability of probiotic bacteria (PB) Lactobacillus acidophilus in a PP‐enhanced milk drink at 4 °C and the in vitroPB adhesion to hydrophilic tissue culture microtitre plates (TCMPs) at 4 °C or 37 °C. The two ASPEs differed slightly in antioxidant activity, PP composition and total extracted PP, vitamin C and uronic acid contents. PB. had over 10× better viability in milk with added PPs than without over a 50‐day storage at 4 °C, while the aqueous extract was more effective than any of the pure PPs, except rutin. PB exhibited significantly greater potential adhesion to intestinal cells in the presence of the aqueous ASPE than the ethanolic ASPE or purified PP, while temperature (4 °C or 37 °C) had a negligible effect on adhesion. Use of apple skin as a source of PPs for enhancing PB functionality in dairy foods may offer a means of deriving value from this waste stream.     

Optimum aqueous extraction conditions for preparation of a phenolic‐enriched Davidson's plum (Davidsonia pruriens F. Muell) extract

This study aimed to optimise aqueous extraction conditions for total phenolic compounds (TPC) from Davidson's plum (Davidsonia pruriens F. Muell) and to assess the physicochemical and antioxidant properties of the phenolic‐enriched extract. The results showed that temperature, time and ratio significantly affected the extraction of TPC. Optimization of extraction conditions was performed using response surface methodology (RSM) utilising a Box–Behnken design. Optimal extraction conditions were determined to be temperature: 90 °C, extraction time: 30 min and solvent to mass ratio: 20:1 mL g^?1. The extracted solid obtained under these conditions had low‐moisture content, high water solubility and contained 45 mg GAE g^?1 of TPC, 22 mg RUE g^?1 of flavonoids, 3.2 mg CAE g^?1 of proanthocyanidins, 2 mg CGE g^?1 of anthocyanidins and 56 mg ACE g^?1 vitamin C. The extract possessed potent antioxidant capacity, but was comparatively lower than those of vitamin E and BHT. Thus, Davidson's plum should be further investigated for its potential health promoting benefits and utilisation in the nutraceutical and food industries.     

Effect of pulse flours on the physiochemical characteristics and sensory acceptance of baked crackers

Pulse flours offer nutritional alternatives to wheat flour in the production of baked snacks due to their high protein and fibre levels and low glycaemic index. In this study, broad‐bean (Vicia faba), yellow‐pea and green‐pea (Pisum sativum) flours were each blended with wheat flour at 40% in the formulation of chemically leavened crackers. The effects of flour type and baking time on the physiochemical properties, sensory acceptability, nutritional composition and antioxidant activity of the crackers were observed in comparison with 100% wheat crackers. Broad‐bean crackers had the highest protein content and antioxidant activity (13 g per 100 g DM and 38.8 mgAAE per 100 g DM, respectively). Yellow‐pea crackers had the highest fibre content (12 g per 100 g DM). Physical dimensions and colour attributes were significantly affected by pulse‐flour substitution. Yellow‐pea and broad‐bean crackers were significantly preferred by consumers compared to the control, demonstrating the potential application of these flours to improve the eating quality and nutritional profile of crackers.     

Effect of Dose and Administration Period of Seed Cake of Genetically Modified and Non-Modified Flax on Selected Antioxidative Activities in Rats

Flaxseed cake containing antioxidants is a valuable dietary component. Its nutritional effect may be diminished by the presence of anti-nutrients. The work was aimed at determining the effect of different contents of flaxseed cake in diets and their administration period on the development of rats and selected parameters of their health status. Diets with 15% and 30% addition of genetically modified (GM) flax seed cake with enhanced synthesis of polyphenols, as well as Linola non-GM flax were administered in short-term (33 days) and long-term (90 days) experiments. The 30% addition of flaxseed cake reduced digestibility of dietary nutrients, GM flaxseed cake lowered body weight gains. The relative weight of selected organs, hematological blood markers and serum activities of aspartate and alanine aminotransferases (AST, ALT) were not affected. Flaxseed cake consumption reduced serum concentration of albumins and increased globulins. Administration of 30% flaxseed cake improved plasma total antioxidant status and 30% GM flaxseed cake lowered liver thiobarbituric acid reactive substances. The activities of superoxide dismutase in erythrocytes, glutathione peroxidase in plasma and the liver concentration of 8-oxo-2′-deoxyguanosine were not changed. Most morphometric parameters of the small intestine did not differ between feeding groups. The administration of diets with 30% addition of flaxseed cake for 90 days improved the antioxidant status in rats.     

Determination of total polyphenols in tea by a flow injection-fiber optic spectrophotometric system

A flow injection-fiber optic spectrophotometric system was established for the online determination of total polyphenol content in tea samples. The method was based on the chromogenic reaction between the phenolic compounds (gallic acid) and ferrous tartrate which was used as the colorimetric reagent and the absorption was determined at the maximum absorption wavelength of 540?nm at 20°C and pH 7.5. The calibration curve from standard solutions of gallic acid was linear in the range from 0.010 to 0.100?mg/mL with a correlation coefficient of 0.9970. The relative standard deviation of polyphenol measurements for eight tea samples was between 0.55 and 3.18%. It can be concluded that the proposed method has allowed simple, fast, and accurate determination of total polyphenol content in tea products.     

Optimisation of lactic acid fermentation of York cabbage for the development of potential probiotic products

In this study, York cabbage was used as the sole substrate for the lactic acid (LA) fermentation with Lactobacillus plantarum. York cabbage was blanched at 95 °C for 12 min to inactivate surface microflora prior to fermentation. To achieve an optimal fermentation condition that would result in higher release of phytochemicals and antioxidant (AO) capacity in the broth, Box‐Behnken design integrating a desirability approach was used. A second‐order polynomial equation was developed, indicating the effect of solute/liquid ratio, agitation rate and fermentation time on desired parameters. The optimised factors were used for fermenting York cabbage to obtain maximum bacterial growth, LA, polyphenols and AO capacity. There was ≈5 log cfu mL^?1 increment in bacterial growth after fermentation, whereas LA production reached up to 4.97 mg mL^?1. Results showed that fermentation retains 95–98% and 90–95% of TPC and AO capacity, respectively. During refrigerated storage (4 °C), the cell numbers, bioactive components and acidity were maintained till 15‐day storage.