Influence of breadmaking on antioxidant capacity of gluten free breads based on rice and buckwheat flours

In the present study new formulations for gluten-free bread based on mixtures of rice (RF) and buckwheat flour (light buckwheat flour (LBF) or wholegrain flour (WBF)), in the proportions of 90:10, 80:20, and 70:30 were made. The gluten-free breads were investigated for their total phenolic content, rutin and quercetin contents, antioxidant activity (AOA) by β-carotene bleaching method, reducing power, scavenging activity on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, and chelating activity on Fe²⁺. The increased amount of LBF or WBF in the dough formulation resulted in the final products with higher antioxidant properties. Baking treatment expressed different influences on antioxidative properties of the final gluten-free product in terms of raw materials, applied recipe and antioxidative capacity in comparison to calculated values based on raw materials. Final gluten-free products were characterized by lower total phenolic and rutin contents, lower antioxidative and reducing activity and on the other hand higher DPPH and chelating activity as well as quercetin content in comparison to calculated values. Bread containing wholegrain buckwheat flour expressed in most of the cases higher values of measured antioxidative parameters than bread prepared with light buckwheat flour and thus contributes to their additional functional property.     

Effect of processing on buckwheat phenolics and antioxidant activity

The effect of processing on functional compounds in buckwheat was investigated. Extractions of buckwheat flour were carried out before and after roasting or extrusion. Folin–Ciocalteu assays indicated that processing did not cause any change in total phenolic content in buckwheat flour. Roasted (200 °C, 10 min) dark buckwheat flour exhibited an increase in non-polar compounds as well as polar compounds whereas extrusion exhibited increase only in polar compounds. Antioxidant activity test (DPPH) showed that roasting at 200 °C for 10 min decreased the antioxidant activity slightly whereas extrusion (170 °C) did not cause any change. The results suggest that processing conditions can be optimized to retain the health promoting compounds in buckwheat products.     

苦荞蛋白水解过程及其水解产物抗氧化活性的初探

阐述了以多肽浓度和水解度(DH)为评价指标,采用木瓜蛋白酶将苦荞麦蛋白水解成为低分子量的苦荞麦多肽的过程。分别对加酶量、pH、固液比、温度、酶解时间五个因素对木瓜蛋白酶酶解效果的影响进行了研究,确定出其适宜工艺条件;并采用亚油酸-硫氰酸铁法确定所制得的苦荞麦多肽液在脂类中的抗氧化活性。     

苦荞中D-手性肌醇的纯化及其抗氧化活性研究

采用超声浸提法提取苦荞D-手性肌醇（DCI）,通过高碘酸钠氧化法测定DCI含量,利用活性炭柱分离纯化苦荞粗提物,高效液相色谱法（HPLC）分析粗提物和纯化产物的组成及含量。以VC、BHT为对照,通过对DPPH自由基、羟自由基、超氧阴离子的体外抗氧化评价体系和总还原力的测定,评价对比苦荞DCI粗提物和纯化产物的抗氧化活性。结果表明,苦荞粗提物中D-手性肌醇的含量仅为0.129%,经活性炭柱纯化后,苦荞中D-手性肌醇的含量可以达到27.26%;苦荞DCI提取物对DPPH自由基、超氧阴离子自由基和羟基自由基均具有不同程度的清除作用,同时具有较好的还原性,且DCI纯化产物的抗氧化活性要明显强于DCI粗提物。      

Quality and antioxidant property of buckwheat enhanced wheat bread

Common buckwheat (Fagopyrium esculentum Moench) was used to substitute 15% of wheat flour to make buckwheat enhanced wheat breads. Proximate composition, physical quality, functional components and antioxidant properties of buckwheat enhanced wheat breads were analysed and compared with those of white bread. Specific volumes of three breads were 6.10–6.75 cm³/g. Buckwheat enhanced wheat bread showed lower lightness and whiteness index values and higher redness and yellowness values. On a seven-point hedonic scale, all sensory results were 5.33–5.91, indicating that three breads were moderately acceptable. No differences were found in appearance, colour and overall sensory attributes for three breads, whereas both buckwheat enhanced wheat breads were rated higher in flavour and mouth feel. Buckwheat enhanced wheat bread contained more rutin and quercetin as expected. Buckwheat enhanced wheat bread was good in antioxidant activity, reducing power and 1,1-diphenyl-2-picrylhydrazyl radical scavenging ability with unhusked buckwheat enhanced wheat bread being the most effective. Overall, buckwheat enhanced wheat bread could be developed as a food with more effective antioxidant properties.     

荞麦芽的抗氧化作用及醛糖还原酶抑制作用的研究

以萌发期为4,6,8,9,10d的甜荞麦芽和苦荞麦芽(黑丰一号,坝上苦荞)为原料,采用高效液相色谱法(HPLC),探明荞麦芽在萌发过程中芦丁的变化趋势,同时观察荞麦芽的ABTS自由基的清除作用以及对大鼠晶状体醛糖还原酶(rAR)的抑制作用。结果表明:无论是甜荞还是苦荞,芦丁的含量都随发芽时间的延长而有所增加,同时黑丰一号苦荞对ABTS自由基的清除作用在萌发的第10天时达最大值(IC50=12.18μg/mL),作用效果高于芦丁标准品(IC50=21.10μg/mL),但是低于对照物Trolox(IC50=3.89μg/mL)。坝上苦荞在萌发的第10天时对rAR抑制活性最大(IC50=2.09μg/mL),作用效果明显高于槲皮素(IC50=2.57μg/mL)、芦丁标准品(IC50=4.90μg/mL)。所以萌发的荞麦芽均有一定的抗氧化作用,且对rAR有明显的抑制作用,可以作为醛糖还原酶抑制剂的良好来源。     

Effect of commercial processing on polyphenols and antioxidant activity of buckwheat seeds

This study analysed the influence of technological processes used in the various buckwheat groat mills on the phenolic content and antioxidant activity of common buckwheat grains and groats. Dehulling, to a greater extent, influenced the quantitative changes in rutin and caused its lowering. Due to this process, the antioxidant activity decreased to a lower degree, and the content of most phenolic acids increased. The roasting process had a negative impact on the content of phenolic compounds, causing the greatest loss in the level of coumaric acid and rutin. It was found that in shaping the health benefits of buckwheat groats, the grain processing temperature is more important than the time of the treatment. In order to obtain the best health value of buckwheat groats, the roasting process should be carried out at a temperature close to 100 °C for a time that will ensure good sensory characteristics, even if it is for several hours.     

超微粉碎对苦荞多酚及抗氧化活性的影响研究

为评价超微粉碎对苦荞多酚及抗氧化活性的影响,分别采用Na NO2-Al(NO3)3法、Folin-Ciocalteu法与高效液相色谱法测定不同粒径苦荞微粉中黄酮、酚与芦丁的含量,DPPH自由基清除法、ABTS+·清除法、总抗氧化能力检测试剂盒评价其抗氧化能力,并分析了酚、黄酮、芦丁含量与抗氧化能力之间的相关性。结果表明:随着微粉化程度的增加,黄酮、酚、芦丁含量及抗氧化能力均呈现先减弱后增强的趋势,但减弱幅度较小,且微粉化程度较高时能较好的保留与提高多酚含量及增加抗氧化活性,对结合态芦丁含量影响不显著;苦荞粉中酚、黄酮、芦丁含量与抗氧化能力之间具有显著的相关性(P0.01)。超微粉碎是一种有效提升苦荞加工食用品质,释放苦荞多酚类植物活性成分的较好加工方式。     

甜荞和苦荞籽中多酚存在形式与抗氧化活性的研究

目的:对比研究两种荞麦籽粒在多酚物质分布、存在形式和抗氧化活性上的差异。方法:以甜荞、苦荞的麸皮和内粉为试材,分别测定其中自由态多酚(free phenolics)、结合态多酚(bound phenolics)、黄酮及芦丁的含量,并利用ABTS+·、DPPH·清除实验及抑制β-胡萝卜素氧化模型分别考察其抗氧化活性。结果:各样品中总酚、总黄酮含量由高到低依次为:苦荞麸粉>苦荞粉>甜荞麸>甜荞粉,各样品间存在显著性差异,其中苦荞麸的总酚与总黄酮含量分别为2433.98mgGAeq/100gDW、3306.60mgRutineq/100gDW,苦荞中芦丁含量远高于甜荞,其中苦荞粉、麸中芦丁含量分别是甜荞对应部位的183～275和136～207倍,但同种荞麦麸、粉间芦丁含量无显著差异。其次,荞麦多酚主要以自由酚形式存在,苦荞粉与甜荞粉自由酚占总酚比例分别为96%、93%,苦荞麸与甜荞麸自由酚占总酚比例分别为95%、88%。此外,荞麦抗氧化能力与多酚含量之间呈线性相关(P>0.90),且苦荞麦麸抗氧化活性最强。结论:荞麦麸多酚含量明显高于荞麦粉,且主要以自由酚形式存在,它们具有较强的抗氧化活性,是优质的功能性食品资源,尤其是苦荞麸。     

Influence of air temperature on drying kinetics and antioxidant potential of olive pomace

This work aims to evaluate the influence of olive pomace drying (a solid by-product of the olive oil industry) on both antioxidant potential and drying kinetics. The two main fractions of olive pomace (pits, PI and pulps + peels, P + P) were characterized by image analysis and density measurement. The drying process was analyzed in experiments carried out at different temperatures (from 50 to 150 °C) and mathematically described from the diffusion and Weibull models. The antioxidant potential of the extracts (ethanol–water 80:20 v/v, 22 ± 1 °C, 170 rpm for 24 h) obtained from the dry product was analyzed by measuring the total phenolic content and antioxidant capacity and the main polyphenols were quantified by HPLC–DAD/MS–MS.     

超声波处理对荞麦种子营养物质累积以及抗氧化活性的影响

采用超声波对荞麦种子进行预处理,测定其萌发率,比较了萌发过程中水分含量、可溶性糖、粗蛋白、总酚和总黄酮的含量,以及体外抗氧化活性的变化。结果表明:10~20min的超声波处理可以提高荞麦的发芽率,而且萌发后荞麦芽的品质有所提高,其抗氧化物质有一定程度的累积,体外抗氧化活性增强。其中以超声波处理20min效果最理想,发芽率提高至94%,总酚含量达到180.8μg GAE/m L,总黄酮含量为156.701mg芦丁/g样品,DPPH自由基清除活力达到最大值(0.197mg Trolox eq/g冻干样)。荞麦萌发之前采用适宜的短时间的超声波处理,不仅能促进萌发,还能促进其抗氧化能力的提高。      

不同光质对苦荞萌发过程中的黄酮类化合物及其抗氧化活性的影响

本文以萌发3 d的苦荞为实验材料,通过红光、黄光、绿光、白光、蓝光、紫外A（254 nm）、紫外C（365 nm）七种不同的光质处理萌发过程中的苦荞,研究了不同光质对萌发苦荞中黄酮类化合物、抗氧化活性以及与黄酮合成和降解有关酶类的影响。实验结果表明:经紫外、蓝光、白光、绿光、黄光和红光处理均可显著地增加苦荞芽中总黄酮和芦丁的含量（与暗处理比较）,不同处理之间有显著性差异（p<0.05）。C段紫外（UV-C）处理后,苦荞芽中总黄酮和芦丁含量最高,与对照相比分别提高了30.1%、40.9%,蓝光处理其次。同时,经光处理后,苦荞芽中黄酮类物质代谢的关键酶苯丙氨酸解氨酶（PAL）和察尔酮异构酶（CHI）活性均显著升高,与总黄酮和芦丁含量呈现正相关。此外,苦荞萌发过程中,光处理可增加苦荞芽对DPPH自由基的清除率,最高可达35.1%,清除率与总黄酮含量呈正相关,表明光处理可以通过增加苦荞芽中黄酮类物质含量进而提高苦荞的抗氧化活性。      

荞麦皮多糖组成及其抗氧化特性分析

筛选提取荞麦皮多糖的温度和乙醇体积分数,对多糖进行红外光谱分析、光学显微镜观察其形貌、紫外光谱分析、HPLC分析其单糖组成,并测定多糖对铁氰化钾的还原能力、羟基自由基和1,1-二苯基-2-三硝基苯肼(DPPH)自由基清除能力。结果表明:80℃水提取的粗多糖质量百分数显著高于其他温度(P <0. 05),且温度对多糖官能团无明显改变;乙醇体积分数为95%时,粗多糖沉淀量显著高于其他各组(P <0. 05);多糖分子是絮状、链状结构,在192 nm处有强烈紫外吸收;荞麦皮多糖主要由甘露糖、核糖、葡萄糖醛酸、葡萄糖、半乳糖、阿拉伯糖组成,其相对质量百分数分别为6. 47%、1. 18%、9. 66%、52. 63%、17. 26%、12. 8%;多糖对铁氰化钾还原能力、羟基自由基和DPPH自由基清除能力具有显著的浓度依赖性(P <0. 05)。荞麦皮多糖主要由6种单糖组成,其抗氧化效果良好,可用作天然的抗氧剂。     

超声波处理对荞麦种子营养物质累积以及抗氧化活性的影响

采用超声波对荞麦种子进行预处理,测定其萌发率,比较了萌发过程中水分含量、可溶性糖、粗蛋白、总酚和总黄酮的含量,以及体外抗氧化活性的变化。结果表明:10~20min的超声波处理可以提高荞麦的发芽率,而且萌发后荞麦芽的品质有所提高,其抗氧化物质有一定程度的累积,体外抗氧化活性增强。其中以超声波处理20min效果最理想,发芽率提高至94%,总酚含量达到180.8μg GAE/m L,总黄酮含量为156.701mg芦丁/g样品,DPPH自由基清除活力达到最大值(0.197mg Trolox eq/g冻干样)。荞麦萌发之前采用适宜的短时间的超声波处理,不仅能促进萌发,还能促进其抗氧化能力的提高。     

超声辅助乙醇提取荞麦黄酮及抗氧化活性研究

以乙醇为提取剂,采用单因素和响应面分析法相结合的手段优选荞麦黄酮超声辅助提取工艺,并研究其体外抗氧化活性。首先通过单因素试验初步探讨了液料比、乙醇体积分数和超声时间3个主要因素对黄酮得率的影响。然后,采用Box-Behnken中心组合设计试验,根据紫外可见分光光度法测的提取效率,建立了回归方程的预测模型。方差和响应面分析结果表明:液料比和乙醇体积分数、及其之间的交互因素对黄酮提取率影响显著,三个因素二次项对黄酮提取率影响均显著。最终,确定荞麦黄酮超声提取的最佳的工艺条件为:液料比36m L/g、乙醇体积分数94%和超声时间41min,此时黄酮的提取率为1.5042mg/g,略低于模型预测值1.5467mg/g。通过DPPH自由基清除率表征提取液抗氧化活性,结果表明荞麦黄酮提取液的抗氧化活性与质量浓度之间具有一定依赖性,其半抑制浓度为0.0162mg/m L。     

超声波辅助提取黑苦荞黄酮类化合物及其抗氧化活性研究

以黑苦荞为原料,通过单因素和正交实验优化超声波辅助提取黑苦荞中黄酮类化合物的工艺,并且研究黄酮类化合物的体外抗氧化活性。结果表明,从黑苦荞中提取黄酮类化合物的最佳工艺条件为:提取温度60℃、超声波功率400 W、乙醇体积分数80%、料液比1∶15,在此条件下提取率达到4.58%;抗氧化活性实验表明,在一定浓度(10⁴0μg/mL)范围内,黑苦荞黄酮类化合物对羟自由基、超氧阴离子自由基和DPPH自由基均有一定的清除作用,但不如Vc的清除效果好。     

葡萄酒生产中酒石稳定性测定方法研究

对目前葡萄酒酒石稳定检测方法进行了总结;在对电导率法和饱和温度法进行验证和分析的基础上,得出了判断葡萄酒酒石稳定的检测方法,这将对优化葡萄酒冷稳处理过程有重要意义。     

Effects of light sources on major flavonoids and antioxidant activity in common buckwheat sprouts

It is known that flavonoids in sprouts were accumulated more under light irradiation than under dark. Light source affecting flavonoid accumulation in sprouts is still investigating. We evaluated the effects of light sources, including red, blue and fluorescent lights, on the flavonoid accumulation and antioxidant activity in common buckwheat sprouts. Experimental results showed that blue light significantly enhanced the contents of C-glycosylflavones, including orientin, vitexin and their isomers, and rutin and a rutin isomer. Sprouts grown under blue light exhibit also the highest total phenolics and total flavonoids as well as the highest antioxidant activities. It was found that isoorientin is the highest antioxidant flavonoid whereas numerous former studies suggested that rutin is a typical antioxidant compound in common buckwheat. These results indicated that blue light could be applied for enhancing not only the content of flavonoids but also antioxidant activity in common buckwheat sprouts.     

苦荞不同部位酚类化合物组成与抗氧化活性

目的:研究苦荞不同部位酚类化合物组成与抗氧化活性。方法:利用70%乙醇分别提取苦荞壳、苦荞麸皮和苦荞粉三部分中的酚类物质,并分析提取物的酚类化合物组成和抗氧化活性。结果:麸皮部位总酚、总黄酮分别为(3 042±31) mg GAE/100 g·DW和(5 290±233) mg RE/100 g·DW,分别占全苦荞的60.8%和67.7%。芦丁是麸皮提取物中的主要酚类化合物,其含量为(5 152±61) mg/100 g·DW。苦荞壳、苦荞麸皮和苦荞粉提取物均表现出抗氧化活性,其中苦荞麸皮提取物的抗氧化活性最强,其ORAC、FRAP、DPPH自由基清除率和ABTS自由基清除率分别为(1 503.3±249.5)μmol/g·DW、(8 477.5±441.1) mg TE/100 g·DW、(5 642.4±241.3) mg TE/100 g·DW和(16 764±742) mg TE/100 g·DW。结论:麸皮是苦荞酚类化合物的主要富集部位,这些化合物表现出较强的抗氧化活性。