Volatile profile,fatty acids composition and total phenolics content of brewers' spent grain by-product with potential use in the development of new functional foods

Brewers' spent grain (BSG) is the insoluble residue generated from the production of wort in the brewing industry. This plant-derived by-product is known to contain significant amounts of valuable components, which remain unexploited in the brewing processes. Therefore, it is essential to develop a more detailed characterization of BSG in order to highlight its potential in developing new value-added products and simultaneously solve the environmental problems related to its discharge. The content of BSG in several biologically active compounds (fatty acids, polyphenols, flavonoids, antioxidant capacity) as well as its volatile fingerprint were assessed and compared with the composition of barley, malt and wheat flour samples. The obtained results emphasized the importance and the opportunities of the re-use of this agro-industrial by-product.     

Contribution of flavonoids to the antioxidant properties of common and tartary buckwheat

The objective of this study was to characterize the flavonoid compounds found in the different grain parts of common and tartary buckwheat, and to determine the contribution of these flavonoids to the antioxidant properties of buckwheat. Eight flavonoid compounds were quantified and their antioxidant activity determined by FRAP, DPPH, and ABTS assays. Of the flavonoid compounds identified rutin was the most abundant, particularly in tartary buckwheat, in which it comprised approximately 90% of total flavonoid content. Flavan-3-ols were detected in common but not tartary buckwheat, and quercetin was detected only in tartary buckwheat. Flavonoid content—in particular, levels of rutin, orientin, and/or epicatechin gallate—was found to influence the total antioxidant activity of buckwheat. Results from this study indicate that antioxidant activity is not only closely associated with flavonoid content, but that different flavonoids contribute differently to the total antioxidant activity of common and tartary buckwheat.     

Superfine grinding improves functional properties and antioxidant capacities of bran dietary fibre from Qingke (hull-less barley) grown in Qinghai-Tibet Plateau,China

The effect of particle size of hull-less barley (HLB) bran DF on antioxidant and physicochemical properties was investigated. HLB bran and extracted DF was ground by regular and superfine grinding, their particle sizes were determined using laser diffraction method. The results showed that superfine grinding could significantly pulverize DF particles to micro-scale; the particle size distribution was close to a Gaussian distribution. The soluble DF in HLB bran was increased effectively with superfine grinding. Insoluble DF with submicron scale showed increased total phenolic content (TPC), DPPH radical scavenging activity and ferric reducing antioxidant power (FRAP). With particle size reduction, the water retention capacity (WRC), swelling capacity (SC), oil binding capacity (OBC), and nitrite ion absorption capacity (NIAC) were significantly (p < 0.05) increased and the water holding capacity (WHC) had no significant change. A kind of health beneficial DF with higher soluble DF content, WRC, SC, OBC, NIAC and antioxidant activity was obtained using superfine grinding.     

Effect of wheat germ flour addition on wheat flour,dough and Chinese steamed bread properties

Wheat germ flour (WGF) has been developed as a functional food ingredient with high nutritional value. In this study, WGF was applied in steamed bread-making in order to improve the quality of Chinese steamed bread (CSB). Partial substitution of wheat flour with WGF at levels of 3%, 6%, 9% and 12% (w/w) was carried out to investigate physicochemical properties of blends and their steaming performance. Falling number (FN) values of composite flours ranged from 199 to 223 s. Viscosity analysis results showed that wheat flour mixed with WGF had higher pasting temperature and lower viscosities. Dough rheological properties were also investigated using farinograph and extensograph. The addition of WGF diluted the gluten protein in dough and formed weak and inextensible dough, which can be studied by scanning electron microscope (SEM) analysis. CSB made with WGF had significantly lower volume, specific volume and higher spread ratio. The sensory acceptability and physicochemical quality of CSB were improved with the application of a low level of WGF (3% and 6%). However, results showed that a high level of WGF over 9% is not recommended because of unsatisfactory taste. As a whole, addition of appropriate level of WGF in wheat flour could improve the quality of CSB.     

Alpha-amylase treatment increases extractable phenolics and antioxidant capacity of oat (Avena nuda L.) flour

In this work, α-amylase was used to treat oat flour with the intent to release phenolic compounds with known antioxidant properties. After methanol extraction, the amounts of nine beneficial phenolic compounds were measured using HPLC. The antioxidant activities of the extracts were assessed using 2,2′-azinobis (3- ethylbenzothiazoline-6-sulfonic acid) (ABTS)，2,2-diphenyl-1-picrylhydrazyl (DPPH), ferric reducing antioxidant power (FRAP) and protein oxidative damage protection assays. Compared with heating-only treated oat flour, that treated with α-amylase showed significant increase of extractable total phenolic content (0.46–1.35 μmol gallic acid equivalents per gram oat), total antioxidant capacity, and an increased ability on the protection of protein from oxidative damage. Heating-only increased caffeic acid and vanillin content by 17 (0.03 vs 0.54 μg/g oat) and 1.8 (0.62 vs 1.11 μg/g oat) folds, but slightly increased the content of other phenols. Excluding heating effect, α-amylase treatment increased gallic acid content by 2.6 folds (0.38 vs 1.38 μg/g oat), caffeic acid content by 2.4 (0.54 vs 1.82 μg/g oat) folds, and other phenols by 1.0–1.8 folds. In conclusion, α-amylase treatment can yield oat products containing more extractable phenolic compounds with increased antioxidant capacity.     

Optimization of the ultrasound-assisted extraction of tryptophan and its derivatives from rice (Oryza sativa) grains through a response surface methodology

An analytical ultrasound-assisted extraction (UAE) technique has been optimized and validated for the extraction of tryptophan and its derivatives from rice grains. A Box–Behnken design in conjunction with a response surface methodology based on six factors and three levels was used to evaluate the effects of the studied factors prior to optimizing the UAE conditions. The significant (p < 0.05) response surface models with high coefficients of determination were fitted to the experimental data. The most significant (p < 0.0001) effect is the solvent-to-sample ratio while quadratic effects caused by temperature and solvent-to-sample ratio were of moderate importance (p < 0.05). The optimal UAE conditions were as follows: extraction time of 5 min, ultrasound amplitude of 30%, cycle of 0.7 s⁻¹, extraction temperature of 30 °C, 8% methanol in water as the extraction solvent at pH 3 and a solvent/solid ratio 5:1. The method validation ensured that appropriate values were obtained for the LOD, LOQ, precision and recovery. Furthermore, the method was successfully applied to the analysis of a number of rice samples of different varieties. It was demonstrated that this particular UAE method is an interesting tool for the determination of tryptophan and tryptophan derivatives in rice grain samples.     

Antioxidant and enzyme inhibition activities and chemical profiles of Polygonum sachalinensis F.Schmidt ex Maxim (Polygonaceae)

Polygonum sachalinensis is a widespread invasive plant in Europe. Chemical profiles of its different organs were studied by HPLC-UV-ESI/MS. Seven major constituents quercetin-3-O-β-D-galactopyranoside, quercetin-3-O-arabinopyranoside, lapathoside D, N-trans-feruloyltyramine, lapathoside C, hydropiperoside, and vanicoside B were isolated and identified. The free radical-scavenging, α/β-glucosidase, and acetylcholinesterase inhibitory activities of crude MeOH extracts and isolated compounds were studied. The structure–activity relationships were discussed. The chemical profiles revealed flavonoids and phenylpropanoids are the major compounds of all the organs of this plant. Quercetin-3-O-arabinopyranoside, lapathoside D, N-trans-feruloyltyramine, lapathoside C and hydropiperoside were isolated from this species for the first time. In the α-glucosidase bioassay, quercetin-3-O-β-D-galactopyranoside, lapathoside D and N-trans-feruloyltyramine demonstrated stronger activities than the positive reference acarbose. The trend in scavenging power showed no relation to enzyme inhibition in the test models.     

基于荧光标记SSR的CID法快速鉴定福建茶树品种

茶树品种真实性鉴定是茶树种质资源研究的重要组成部分,是茶树品种知识产权保护的前提。在茶树基因组上按照均匀分布的原则选择45个SSR标记合成荧光标记引物,利用这些标记引物对54个福建无性系茶树品种进行PCR扩增,标记基因型分型后进一步筛选出9个SSR标记核心引物。这批核心引物的多态性信息含量(Polymorphism information content,PIC)均大于0.5,等位位点数在3~5之间,基因型数在5~10之间,属于高度多态性引物且方便进行基因型数据统计,适宜用来进行无性系茶树品种的真实性鉴定。利用其中的6个标记核心引物建立了54个福建无性系茶树品种的品种鉴别图(Cultivar identification diagram,CID),该CID能直观地提供对其中任意品种进行鉴定所需要的标记引物以及相应的标记基因型,且能够方便地进行扩容以用来对更多的无性系茶树品种进行真实性鉴定。利用该方法对无性系茶树品种进行真实性鉴定,操作方便、快速准确、稳定性高、实用性强。本实验所获得的茶树品种鉴定图(CID)对茶树品种知识产权保护,以及促进茶树品种选育工作健康可持续发展具有重要的意义。     

Bioactivity and chemical components of Thai rice in five stages of grain development

Tracking changes in the bioactive compounds of white (ML-W), red (ML-R) and black (RB) rice during the 5 stages of grain development were studied. Total anthocyanin (TAC) was found only in RB (stages 3–5) and proanthocyanidin (TPAC) contents were only found in ML-R (stages 2–5). Considerable amounts of total phenolic contents (TPC) were found in stages 2–4 of ML-R, while total flavonoid contents (TFC) were most detected in stages 4–5 of RB. The DPPH activity of ML-W and ML-R decreased from stages 1–5. The highest FRAP activity was found in ML-R (stages 2–3) indicating that it is highly related to the bioactive compound content. Cyanidin-3-glucoside and peonidin-3-glucoside were found in RB at stages 3–5. The cyanidin of RB in stages 4–5 was related to the amount of TAC. The proanthocyanidin compound catechin was first found and reported in stages 2–3 of ML-R. Principal component analysis indicated that antioxidant activity and the bioactive components were highly related. The data from this study suggests that ML-R at stage 2 and RB at stage 4 are the most suitable stages for harvesting to achieve the highest level of bioactive compounds, which have many health benefits.