冲泡条件对福鼎白茶茶汤多酚含量和抗氧化活性的影响

以福鼎白茶为材料,采用单因素和正交试验研究冲泡条件对其茶汤茶多酚含量和抗氧化活性的影响及其相关性。单因素试验结果表明,冲泡温度、时间、次数能够显著影响福鼎白茶茶汤茶多酚含量,而不同因素对DPPH清除率的影响较不规律;茶汤茶多酚含量和抗氧化活性在冲泡温度方面显著正相关,而在冲泡时间和次数方面相关性较弱。正交试验结果表明,各因素对茶汤茶多酚含量的影响程度大小为:冲泡温度>冲泡次数>冲泡时间,最高茶多酚含量(146.37 mg/g)的冲泡条件为:冲泡时间7 min、冲泡次数1次、冲泡温度100℃。各因素对DPPH清除率的影响顺序为:冲泡时间>冲泡温度>冲泡次数,最高清除率(93.59%)的冲泡条件为90℃下冲泡5 min、冲泡1次。     

Effect of Drying on the Phenolic Content and Antioxidant Activity of Red Grape Pomace

Winemaking by-products are considered to be a rich source of bioactive compounds. Grape pomace is susceptible to microbial degradation due to the degree of residual moisture, so the drying of this pomace for conservation is considered to be an essential first step. Previous studies concerning the way in which drying affects winery by-products have produced contradictory results. In this study, a new methodology for drying grape pomace in a climatic chamber has been evaluated. Five red grape pomace varieties were dried in a climatic chamber at 40 °C and 10% relative humidity and the phenolic content and antioxidant activity of the dried and wet pomace samples were compared. The results indicate that this drying process is both feasible and beneficial because significant increases in the extractability of phenolic compounds and antioxidant activity were achieved.     

光照对黑青稞萌发过程中褪黑素、酚类物质含量和抗氧化活性的影响

为研究光照对青稞萌发过程中功能成分的影响,以隆子黑青稞为材料,采用酶联免疫吸附法和分光光度计法测定了不同光照时间处理下黑青稞萌发过程中褪黑素、总酚和总黄酮含量及其抗氧化活性;同时测定了黑青稞发芽率、胚根和胚芽长度,并对避光萌发5 d的芽苗进行了感官评定.结果表明,随萌发时间的延长,青稞芽苗中褪黑素、总酚和总黄酮含量与种...     

热烫处理对黑胡椒色泽和胡椒碱含量的影响

为研究热烫处理对黑胡椒色泽的影响，考察了热烫处理温度(70、80、90℃)、热烫处理时间(30、60、120 s)对胡椒色差和胡椒碱含量的影响。结果表明，热烫处理有助于胡椒黑色色泽的形成，在同一热烫处理条件下，绿色胡椒鲜果更易形成黑色色泽。热烫处理能显著缩短胡椒果的干燥时间。热烫处理温度在70～80℃、处理120 s以内，对胡椒中胡椒碱含量影响不显著，适宜加工黑胡椒。     

Salt Effect on the Antioxidant Activity of Red Microalgal Sulfated Polysaccharides in Soy-Bean Formula

Sulfated polysaccharides produced by microalgae, which are known to exhibit various biological activities, may potentially serve as natural antioxidant sources. To date, only a few studies have examined the antioxidant bioactivity of red microalgal polysaccharides. In this research, the effect of different salts on the antioxidant activities of two red microalgal sulfated polysaccharides derived from Porphyridium sp. and Porphyridium aerugineum were studied in a soy bean-based infant milk formula. Salt composition and concentration were both shown to affect the polysaccharides’ antioxidant activity. It can be postulated that the salt ions intefer with the polysaccharide chains’ interactions and alter their structure, leading to a new three-dimensional structure that better exposes antiooxidant sites in comparison to the polysaccharide without salt supplement. Among the cations that were studied, Ca²⁺ had the strongest enhancement effect on antioxidant activities of both polysaccharides. Understanding the effect of salts on polysaccharides’ stucture, in addition to furthering knowledge on polysaccharide bioactivities, may also shed light on the position of the antioxidant active sites.     

A Comparative Analysis of Free, Bound and Total Lipid Content on Spelt and Winter Wheat Wholemeal

Free lipids (FL), bound lipids (BL) and total lipids (TL) were determined by the Soxhlet method in whole ground spelt (Triticum aestivum ssp. spelta L.) and hexaploid winter wheat (T. aestivum) samples. Ninety-one samples of spelt and 78 samples of winter wheat were analysed in the present study. The available material is representative of the wide variability found in spelt (true spelt forms compared with spelt wheat hybrid material). The results show that spelt differs from winter wheat by a higher FL and TL content (on average, 1·3 times and 1·2 times respectively). Furthermore, our results demonstrate that FL account for most of the high TL content of spelt as compared to winter wheat. Lipid content is a parameter which allows a distinction between spelt and winter wheat. This could be useful for breeders to classify spelt varieties.     

Effect of High-Energy Milling on Bioactive Compounds and Antioxidant Capacity in Nixtamalized Creole Corn Flours

Plant Foods for Human Nutrition - This study aimed at evaluating the effect of high-energy milling (HEM) and traditional nixtamalization (TN) on bioactive compounds and antioxidant capacity in...     

超高压处理对豆乳总多酚、类黄酮含量及其抗氧化性的影响

研究了豆乳经超高压处理后,其总多酚、类黄酮含量的变化,并用DPPH法、FRAP法分析了上述处理对豆乳体外抗氧化活性的影响.结果表明:200 MPa处理对豆乳中总多酚无显著影响(P>0.05),300、400、500 MPa处理后的总多酚则显著增加(P<0.05),加热处理后显著下降(P<0.05).400、500 MP...     

Effect of DHA Containing Oils and Powders on Baking Performance and Quality of White Pan Bread

Different sources of DHA and/or n-3 (omega-3) rich oils, oil emulsions and microencapsulated (ME) powders were tested at two different concentrations with the aim of producing fortified pan bread. Three oils (S-algae, fish and flax), two emulsified algae oils (Emulsion-P and Emulsion-L) and two ME oils (ME-S algae and ME-C algae) were compared. The DHA and n-3 oils replaced part of the shortening in order to obtain 32 g slices enriched with 25 or 50 mg DHA, 35 or 70 mg total n-3 from fish oil and 90 or 180 mg linolenic from flax oil. Addition of oils did not significantly affect water absorption but reduced mix time whereas addition of the ME oils decreased both water absorption and mix time. Breads enriched with flax or ME-C oils had lower volume and higher density than the control, ME-S algae, Emulsion-P and Emulsion-L breads. All breads lost texture throughout 14 d storage, the major changes occurred after 3 d. The ME-S algae oil bread had the best softness after 14 d storage whereas breads produced from ME-S algae or ME-C algae oils had the poorest texture. Sensory evaluations indicated that the color of the ME-S algae oil fortified bread was significantly less preferred than the other loaves. After 6 d the control bread had higher acceptability compared with the rest of the breads enriched with high levels of DHA or omega-3 oils. The high-enriched fish oil bread was well accepted during the first days of storage but had the least preferred acceptability after 13 d. The best fortified breads were those supplemented with S-algae oil, Emulsion-P and Emulsion-L oils.     

醋制对黑豆蛋白含量及多肽ACE抑制活性的影响

为考察醋制对黑豆蛋白含量及多肽ACE抑制活性的影响,为对黑豆醋浸过程中蛋白组分及含量变化进行分析,并对相应ACE抑制肽活性进行测定。黑豆经醋浸不同时间后,采用顺序抽提法提取清蛋白、球蛋白、醇溶蛋白和谷蛋白,并采用凯氏定氮法及SDS-PAGE电泳进行定量和定性分析;各蛋白组分经胃蛋白酶水解,经超滤(截留分子量3 k D)后收集滤液,获得多肽组分,RP-HPLC法进行ACE抑制活性评价。结果表明:经醋浸14 d后,黑豆总蛋白含量变化幅度小于±0.5%;清蛋白含量由55.13%(0 d)降低至9.61%(14 d);球蛋白由7.04%(0 d)增加到20.34%(14 d);醇溶蛋白由0.81%(0 d)增加到1.72(14 d);谷蛋白由21.11%(0 d)增加到59.45%(14 d),含量最高。醋浸处理降低了清蛋白源多肽的ACE抑制活性,但提高了球蛋白、醇溶蛋白及谷蛋白多肽的ACE抑制活性,其中,谷蛋白多肽抑制率由18.18%(0 d)增加至37.58%(14 d),抑制活性升高。醋浸可改变黑豆各蛋白组分的含量和对应多肽的ACE抑制活性,其中,谷蛋白含量及其多肽ACE抑制活性均有增加。研究结果表明可进一步采用分离纯化技术从谷蛋白多肽中获得高活性降压肽。     

Antioxidant Activity and Phenolic Content of Betalain Extracts from Intact Plants and Hairy Root Cultures of the Red Beetroot Beta vulgaris cv. Detroit Dark Red

Betalains are water-soluble plant pigments that are widely used as food colorants, and have a wide range of desirable biological activities, including antioxidant, anti-inflammatory, hepatoprotective, anti-cancer properties. They can be produced from various plants, notably beetroot, but betalain products obtained in this way also have some undesirable properties and are difficult to standardize. A potentially attractive alternative is to use hairy root cultures. In the study reported here, we found that betalain extracts obtained from hairy root cultures of the red beetroot B. vulgaris cv. Detroit Dark Red also had higher antioxidant activity than extracts obtained from mature beetroots: six-fold higher 2,2-dyphenyl-1-picrylhydrazyl radical scavenging ability (90.7% inhibition, EC₅₀ = 0.11 mg, vs 14.2% inhibition, EC₅₀ = 0.70 mg) and 3.28-fold higher oxygen radical absorbance capacity (4,100 μM TE/g dry extract, vs 1,250 μM TE/g dry extract). The high antioxidant activity of the hairy root extracts was associated with increased concentrations (more than 20-fold) of total phenolic concomitant compounds, which may have synergistic effects with betalains. The presence of 4-hydroxybenzoic acid, caffeic acid, catechin hydrate, and epicatechin were detected in both types of extract, but at different concentrations. Rutin was only present at high concentration (1.096 mg.g⁻¹ dry extract) in betalain extracts from the hairy root cultures, whereas chlorogenic acid was only detected at measurable concentrations in extracts from intact plants.     

朝鲜淫羊藿中总黄酮含量测定及其抗氧化活性研究

目的测定朝鲜淫羊藿中总黄酮含量,并研究其抗氧化活性。方法采用醇提法提取供试品,利用紫外可见分光光度法对其进行含量测定.进行体外抗氧化活性实验,并与同等条件下Vc的抗氧化能力进行比较,采用对比实验进行方法总结来研究朝鲜淫羊藿中总黄酮的抗氧化作用。结果本实验在超声提取条件下的提取率为25.84%,朝鲜淫羊藿有较好的抗氧化活性,在同等条件下,其抗氧化活性较Vc稍弱。     

光质对茶树愈伤组织中茶多酚及抗氧化酶活性的影响

以龙井43成熟茶籽为外植体诱导出的愈伤组织为材料,通过测定茶多酚含量（TP）及超氧化物歧化酶（SOD）和过氧化氢酶（CAT）等抗氧化酶活性的变化,研究了不同光质对次生代谢产物和酶活性的影响。结果表明,用不同的光质处理愈伤组织,愈伤组织中茶多酚含量、超氧化物歧化酶活性以及过氧化氢酶活性因光质和处理时间不同而异。蓝光处理下愈伤组织生长较好;各处理1~10d茶多酚含量增加,10~20d降低,蓝光处理下茶多酚含量低于对照,红光处理则高于对照,而绿光、黄光对其影响不显著;白光处理下SOD活性显著高于其余各组处理,红光处理下活性则显著低于各组处理;白光处理CAT的活性也显著高于其余各组处理,而绿光和黄光可能不利于CAT的合成。     

保护性耕作对黑土农田土壤水热及作物产量的影响

保护性耕作措施是干旱区农田提高作物产量的有效耕作技术,为研究其在冷凉区域的适用性,于2004～2009年,以中国科学院海伦农业生态试验站黑土农田为研究对象,开展了免耕秸秆覆盖、少耕和传统旋耕3种耕作措施长期定位对比研究.结果表明:在大豆玉米轮作制度下,实施免耕秸秆覆盖和少耕的保护性耕作方式,连续3 a免耕大豆产量均表现...     

Influence of Extraction Solvents on Antioxidant Activity and the Content of Bioactive Compounds in Non-pungent Peppers

Bioactive compounds in foods have been shown to maintain human health. However, the relative amounts of bioactive compounds and the variation in the amounts are still poorly understood. In this study, the efficacy of different extraction solvents (hexane, ethyl acetate, acetone, methanol, and a methanol:water mixture), as well as the levels of certain bioactive compounds in non-pungent pepper cultivars (TMH, TMJ, PA137, and B58) were investigated using high-performance liquid chromatography (HPLC). Antioxidant activities were determined using 2,2,-diphenyl-1-picrylhydrazyl (DPPH), reducing power, and deoxyribose degradation. Hexane extracts had the highest level of carotenoids (47.2-628.8 μg/g), and methanol extracts contained maximum flavonoids (24.9-152.2 μg/g) in four different cultivars. Higher DPPH scavenging activity was found in the hexane extracts from TMH, TMJ, PA137, and B58 (IC?? value: 0.67, 0.74, 0.55, and 0.48 μg/ml, respectively), whereas the reducing power was high in ethyl acetate and acetone extracts. Inhibition of deoxyribose degradation was highest in methanolic extracts from TMH, TMJ, PA137, and B58 (51.2, 49.5, 52.6, and 47.4 %, respectively). These data demonstrate that solvent chemical properties such as polarity can differentially impact the efficiency with which different bioactive compounds are recovered from foods, and this could lead to differences in estimated biological activity such as antioxidant capacity.     

Effect of Extrusion Conditions and the Optimization of Phenolic Compound Content and Antioxidant Activity of Wheat Bran Using Response Surface Methodology

The extrusion process (EP) consists of heat and mechanical treatments under different conditions of moisture, shear, and pressure and rapidly causes structural alterations and changes in the functional properties of the extruded material. The aim of this study was to evaluate the effect of extrusion conditions and optimize the wheat bran extrusion conditions to achieve the greatest content of phenolic compounds and antioxidant activity using response surface methodology. The EP factors evaluated were feed moisture (FM) (25–33.54%) and final extrusion temperature (T) (140–180 °C). The properties evaluated in the extruded material were bound total phenol content (BTPC), total phenolic compounds and antioxidant activity (AOX). Analysis of variance (ANOVA) and response surface methodology were used in the evaluation. The determination coefficients, (FM)² and (T)², very significantly affected the BTPC and bound 2,2-diphenyl-1-picrylhydrazyl content (BDPPHC). The optimization was performed by overlaying two contour plots to predict the best combination regions. The optimized extrusion conditions were the following: FM?=?30% and T?=?140 °C, which provided BTPC?=?3547.01 μgGAE/g (predicted: 3589.3 μgGAE/g) and BDPPHC?=?9.5 μmolTE/g (predicted: 10.4 μmolTE/g); and FM?=?30% and T?=?180 °C, which provided BTPC?=?3342.3 μgGAE/g (predicted: 3727.7 μgGAE/g) and BDPPHC?=?9.5 μmolTE/g (predicted: 9.3 μmolTE/g). The EP increased the phenolic compounds and AOX, and enhancement of these properties in wheat bran products could make them functional foods.     

Multivariable Analysis of Gluten-Free Pasta Elaborated with Non-Conventional Flours Based on the Phenolic Profile,Antioxidant Capacity and Color

The phenolic compounds, color and antioxidant capacity of gluten-free pasta prepared with non-conventional flours such as chickpea (CHF), unripe plantain (UPF), white maize (WMF) and blue maize (BMF) were analyzed. Fifteen phenolic compounds (five anthocyanins, five hydroxybenzoic acids, three hydroxycinnamic acids, one hydroxyphenylacetic acid and one flavonol) were identified in pasta prepared with blue maize, and 10 compounds were identified for samples prepared with white maize. The principal component analysis (PCA) led to results describing 98% of the total variance establishing a clear separation for each pasta. Both the proportion (25, 50 and 75%) and type of maize flour (white and blue) affected the color parameters (L*, C _ab *, h _ab and ΔE* _ab ) and antioxidant properties (DPPH, ABTS and FRAP methods) of samples, thus producing gluten-free products with potential health benefits intended for general consumers (including the population with celiac disease).     

土壤肥力对小麦开花后各器官游离氨基酸和籽粒蛋白质含量变化的影响

能过随机区组试验和相关的方法，研究了两种土壤肥力条件下小麦开花后植株体内游离氨基酸含量的变化动态及其与籽粒蛋白质含量的关系。结果表明，开花后小麦植株各器官游离氨基酸含量均与籽粒蛋白质含量呈显著或极显著正相关，土壤肥力高能够显著提高各器官中的游离基酸含量，并延长维持高水平的时间，进而促进籽粒蛋白质合成，提高籽闰蛋白质含量和改善品质。     

枯草芽孢杆菌对植烟土壤养分含量与酶活性的影响

为探讨枯草芽孢杆菌微生物菌剂对土壤主要养分含量及酶活性的影响,以及施用枯草芽孢杆菌后的土壤养分与酶活性间的关联性,以K326为材料,开展了枯草芽孢杆菌微生物菌剂不同用量研究。结果表明:烤烟移栽以后,(1)土壤有机质含量呈现下降趋势;碱解氮和有效磷、钾含量则呈现"低-高-低"的变化规律,且烤烟移栽后45 d达到最大值;(2)土壤脲酶活性呈现由低到高的变化,移栽后90 d达到最大值;过氧化氢酶活性呈现"低-高(60 d)-低-较高(90 d)"的规律性变化;蔗糖酶活性出现"较高-低(60 d)-高(75 d)-高(90 d)"的规律性变化;(3)通过土壤酶活性对土壤有机质、碱解氮和速效磷、钾含量间的灰色关联分析表明,土壤脲酶活性在移栽后45 d对有机质和碱解氮,以及移栽后60 d对速效磷和钾含量影响最大;过氧化氢酶和蔗糖酶活性,分别在移栽后60 d和75 d,对土壤有机质、碱解氮,及速效磷和钾的含量影响最大。植烟土壤施用枯草芽孢杆菌,对提高土壤养分含量及酶活性有着良好的效果,不同生长阶段土壤养分与酶间相互作用有差异。