国产小麦品种麸皮结构层的定性和定量分析方法

选取6种代表性中国小麦,对麦麸结构层进行手工剥离、显微观测和特征组分分析,从而建立国产麦麸结构层的定性和定量分析方法。结果表明,国产小麦中麸皮的平均比例为18%,外果皮、中间层和糊粉层分别占22%、31%和47%;通过光学和荧光显微镜可定性判定麦麸结构层;麦麸中间层中烷基间苯二酚(ARs)的含量达11.9 mg/g,分别是外果皮和糊粉层中含量的110倍和230倍,而糊粉层中总磷的平均含量为28.7 mg/g,超过外果皮和中间层中含量的20倍。因此,ARs和磷可分别作为中间层和糊粉层的标示物,外果皮可通过计算获得。结合显微观测和标示物定量的方法,可实现全麦产品中麦麸及其结构层的添加量的快速分析。     

Ferulic acid and its position among the phenolic compounds of wheat

Ferulic acid (3-methoxy-4-hydroxycinnamic acid) is the main phenolic acid occurring in cell walls of monocotyledones. Due to its blue-and-white fluorescence it is easily identified and is located in the cereal grain morphological parts. Its 40-fold greater concentration was found in the cells walls of the seed coat and aleuronic layer than in the cells walls of endosperm. Most often, it is linked by ester bonds with hemicellulose chains, mainly with arabinose residues and it also polymerizes with lignin through ether bonds. However, ferulic acid in the pentosane molecules forms specific complexes with proteins through chemical bonds with amino acids. It is interesting to mention the theory of the pentosane gel formation in which a great role is assigned to ferulic acid. An oxidized form of ferulic acid-diferulic acid-produces gel formation by linking two pentosane or protein molecules. The blue-and-white fluorescence of ferulic acid can be applied to determine flour contamination with grain coat particles and its ability to form complexes with pentosanes and proteins is important in the formation of dough texture with its semi-elastic properties.     

In Vitro Potential of Ascophyllum nodosum Phenolic Antioxidant-Mediated α-Glucosidase and α-Amylase Inhibition

ABSTRACT: Ascophyllum nodosum is a brown seaweed that grows abundantly in the Northeast coastal region. In this study, the potential of A. nodosum for type 2 diabetes management through antioxidant-mediated α-glucosidase and α-amylase inhibition was investigated. After the initial screening of 4 locally harvested seaweeds, A. nodosum was chosen for its highest phenolic content and was subjected to water extraction. Among extraction ratios of 50 g to 100 to 1000 mL at room temperature, 50 g/400 mL yielded the highest phenolic content of 4.5 mg/g wet weight. For evaluation of extraction temperature ranging from 20 to 80 °C, 50 g/400 mL was chosen as a minimum amount of extractant. Among temperatures studied, extraction at 80 °C resulted in the highest total phenolic contents (4.2 mg/g wet weight). All extracts had similar levels of antioxidant activity in the range of 60% to 70% in terms of 1, 1-diphenyl-2-picrylhydrazyl (DPPH) free radical scavenging activity. The 80 °C extract had the highest α-glucosidase and α-amylase inhibitory activity with IC₅₀ of 0.24 and 1.34 μg phenolics, respectively, compared to the IC₅₀ of acarbose, reference inhibitor, being 0.37 and 0.68 μg. The results show that fresh A. nodosum has strong α-glucosidase and mild α-amylase inhibitory activities that correlated with phenolic contents. This study suggests a nutraceutical potential of A. nodosum based on phytochemical antioxidant and antihyperglycemia activities.     

小麦中植物化学素的研究进展

综述了小麦中的一些植物化学素如酚类、低聚糖类、植物甾醇等及其生理活性与人类健康的关系。     

Inhibition of Horse Bean and Germinated Barley Lipoxygenases by Some Phenolic Compounds

Phenolic compounds have been repeatedly implicated as potent antioxidants. Efficiency has been frequently estimated by radical scavenging activity and few reports have considered lipoxygenase (LOX) inhibition. Horse bean LOX was inhibited by a range of phenolic acids, gallates and flavonoids. All compounds tested were uncompetitive inhibitors with the exception of flavonol aglycons which were non competitive type. In each class of compounds, inhibition constants were strongly affected by structures. Inhibition patterns of (-)-epicatechin on germinated barley LOXs were detailed: (-)-epicatechin acted as an uncompetitive inhibitor while (-)-epicatechin reduced hydroperoxide formation by its radical scavenging activity and thus limited enzyme activation.     

小麦麸皮中束缚型酚酸的化学法释放工艺

研究小麦麸皮中主要抗氧化活性物质束缚型酚酸的化学法释放工艺。利用超声辅助碱解技术进行酚酸成分的释放,通过单因素试验确定因素与水平,应用Box-Behnken 设计三因素三水平的试验,依据回归分析确定最优的提取工艺条件。结果表明,化学法释放小麦麸皮酚酸的优化提取工艺条件为粉碎粒径0.5mm、温度60℃、时间1h、碱液浓度0.1mol/L、料液比2.5:100(g/mL),提取的总酚释放量为3.687mg/g。处理后的麦麸中游离型酚酸的含量与传统醇提法相比,提高了7.23 倍。     

麦麸酚类化合物研究进展

麦麸是小麦加工的主要副产品,除了营养成分外,麦麸中还含有酚酸、黄酮、木酚素等酚类化合物,具有一定的功能活性。本文从分布情况、功能活性、提取方法等方面阐述了这些酚类化合物的研究现状,对麦麸酚类化合物的研究前景进行了展望。     

Canarium zeylanicum seed oil: an edible oil with beneficial qualities

The quality parameters, fatty acid composition, phenolic compounds and antioxidant properties of the seed oil of Canarium zeylanicum were determined. The results indicate that the seed oil of Canarium zeylanicum is an excellent source of essential fatty acids which contains C18:2 (49.35 ± 0.35%) and C18:3 (19.09 ± 0.01%). The total phenol contents of the seed oil and the seed hull of Canarium zeylanicum were 66 ± 6 and 2014 ± 14 mg kg⁻¹respectively. The identified phenolic acids in the methanolic extracts of seed oil include 3,4-dihydroxybenzoic acid, p -hydroxybenzoic acid, vanillic acid and ellagic acid. Diphenyl-2-picrylhydrasyl radical scavenging activity, inhibition of deoxyribose degradation and the reducing power of the methanolic extracts of seed oil and seed hull of Canarium zeylanicum are comparable with those of butylated hydroxytoluene solutions.     

Characterization of Enzyme Released Antioxidant Phenolic Acids and Xylooligosaccharides from Different Graminaceae or Poaceae Members

Xylooligosacchrides (XOS) and phenolic acids were simultaneously produced from hemicelluloses using crude enzyme mixture synthesized by a novel Bacillus subtilis KCX006. The strain synthesized XOS-forming endo-xylanase and de-branching α-L-arabinofuranosidase and esterase but not β-xylosidase. This enzyme mixture can improve the yield of XOS and phenolic acids from xylan due to the absence of hydrolysis of XOS by β-xylosidase and release of phenolic acids by esterase. Hence, the enzyme mixture was tested for simultaneous production of XOS and phenolic acids from xylan (28–35%)-rich Graminaceae or Poaceae plant biomass, such as wheat bran, sugarcane bagasse, bamboo, and rise husk. Hemicellulose fractions of the biomasses were extracted by alkaline treatment and hydrolyzed using crude xylanase mixture. The profiles of XOS and phenolic acids formed were analyzed by HPLC. The lyophilized hydrolytic products were further analysed by ¹H NMR to identify the substitutions in XOS. The observed profile of XOS and phenolic acids varied with the biomass sources. Maximum amounts of XOS (665.2 mg/g dwt) and phenolic acids (89.69 μg/g dwt) were produced from hemicellulose A fractions of sugarcane bagasse and bamboo bagasse, respectively. HPLC and ¹H NMR analysis of XOS revealed the formation of free- and arabino-XOS. Phenolic acids consisted of hydroxycinnamic and hydroxybenzoic acids and the antioxidant activity correlated well with hydroxycinnamic acids content. The crude enzyme of B. subtilis is useful to produce mixture of XOS and phenolic acids from biomass.     

Superfruits: Phytochemicals,antioxidant efficacies,and health effects – A comprehensive review

The term “superfruit” has gained increasing usage and attention recently with the marketing strategy to promote the extraordinary health benefits of some exotic fruits, which may not have worldwide popularity. This has led to many studies with the identification and quantification of various groups of phytochemicals. This contribution discusses phytochemical compositions, antioxidant efficacies, and potential health benefits of the main superfruits such as açai, acerola, camu-camu, goji berry, jaboticaba, jambolão, maqui, noni, and pitanga. Novel product formulations, safety aspects, and future perspectives of these superfruits have also been covered. Research findings from the existing literature published within the last 10 years have been compiled and summarized. These superfruits having numerous phytochemicals (phenolic acids, flavonoids, proanthocyanidins, iridoids, coumarins, hydrolysable tannins, carotenoids, and anthocyanins) together with their corresponding antioxidant activities, have increasingly been utilized. Hence, these superfruits can be considered as a valuable source of functional foods due to the phytochemical compositions and their corresponding antioxidant activities. The phytochemicals from superfruits are bioaccessible and bioavailable in humans with promising health benefits. More well-designed human explorative studies are needed to validate the health benefits of these superfruits.