发酵豆粕中异黄酮热稳定抗氧化性的研究

为开发利用发酵豆粕中异黄酮(FSMI)天然食品抗氧化剂,采用烘箱贮藏法,以过氧化值为指标,研究了高温(120℃)下FSMI对猪油和菜籽油的抗氧化作用.结果表明:在高温下,FSMI具有良好的抗氧化稳定性,并且随着FSMI添加量的增加,其抗氧化作用显著增强;对猪油和菜籽油的抗氧化效果优于同浓度的SMI(从豆粕中提取的异黄酮)、茶多酚和BHT;并对由金属离子(Cu2+、Fe2+)引起的促氧化作用有明显的抑制效应.     

葛根异黄酮类化合物提取工艺优化及其抗氧化活性研究

目的:研究葛根异黄酮类化合物的最优提取工艺及其体外抗氧化能力。方法:在单因素试验的基础上设计正交试验,通过方差分析和多重比较确定最优提取工艺。以超氧阴离子自由基(O2-·)、羟基自由基(·OH)、1,1-二苯基-2-苯基自由基(DPPH·)清除率测定法及还原力测定法评价异黄酮类化合物体外抗氧化活性。结果:最佳工艺条件是:提取时间1 h、料液比1∶20、提取温度80℃、乙醇体积分数50%。异黄酮类化合物在0~1mg/m L质量浓度范围具有较明显的抗氧化活性,并随着质量浓度的增加活性增强。其对超氧阴离子自由基的清除率达到57.1%,对羟基自由基的清除率达到52.04%,对1,1-二苯基-2-苯基自由基的清除率达到45.9%。结论:葛根中含有较多的异黄酮类化合物,具有体外抗氧化活性。     

3种豆芽中异黄酮、多酚的体外抗氧化活性及其对果蝇SOD、GSH-Px活力的影响

采用高效液相色谱(HPLC)等方法测定黑豆、黄豆、绿豆豆芽中异黄酮、多酚的水平,采用1,1-二苯基-2-三硝基苯肼(DPPH)和2,2’-连氨-(3-乙基苯并噻唑啉-6-磺酸)二氨盐(ABTS)方法分析3种豆芽异黄酮和多酚的体外抗氧化活性,研究异黄酮对黑腹果蝇体内超氧化物歧化酶(SOD)和谷胱甘肽过氧化物酶(GSH-Px)活力的影响。结果表明:黑豆芽的异黄酮、多酚含量最高,黄豆芽次之,绿豆芽最低。4种异黄酮单体中,从黑豆芽中检出染料木苷、大豆苷和黄豆黄苷,从黄豆芽中检出染料木苷和大豆苷,从绿豆芽中只检出大豆苷。3种豆芽异黄酮、多酚提取物的ABTS·+和DPPH·自由基清除能力具有剂量依赖性,拟合方程的相关系数(R2)在0.8957～0.9997区间,提示异黄酮、多酚质量浓度与自由基清除率之间具有较好的量效关系。黑豆芽异黄酮、多酚的IC50值最低,黄豆芽次之,绿豆芽最高,表明黑豆芽的自由基清除能力优于黄豆芽和绿豆芽。3种豆芽异黄酮的IC50值均低于多酚,说明异黄酮的体外抗氧化活性高于多酚。用含有0.5mg/g豆芽异黄酮的培养基饲喂果蝇,可使其SOD、GSH-Px活力明显升高。黑豆芽异黄酮提升果蝇抗氧化酶活力的效果最佳,优于黄豆芽和绿豆芽。本研究为豆芽食品的开发提供了参考依据。     

发酵豆粕中异黄酮的抗氧化和抗菌活性的研究

为开发利用发酵豆粕中异黄酮(FSMI)天然食品抗氧化剂和防腐剂,主要研究了FSMI的抗氧化和抗菌活性。研究结果表明:FSMI对大豆油和菜籽油具有抗氧化作用,其抗氧化性能高于同浓度的未发酵豆粕中的异黄酮(SMI)和化学合成的抗氧化剂BHT,另外,FSMI具有较强的抗菌活性,对食品中常见细菌和真菌的最低抑(杀)浓度分别为0.24%和0.56%,优于SMI和化学合成的防腐剂苯甲酸钠。     

大豆异黄酮的提取及其抗氧化稳定性研究

以大豆粉为原料,分别以超声波辅助和微波辅助提取大豆异黄酮。在单因素实验基础上,通过正交试验优化确定最佳提取工艺。结果表明:大豆提取异黄酮工艺方法中超声辅助提取法优于微波辅助提取法,其最佳工艺条件为:乙醇质量分数80%,超声时间20 min,超声温度50℃,料液比1∶20。金属离子除K+和Ca2+外,Zn2+、Cu2+、Mg2+对大豆异黄酮抗氧化活性稳定性影响较为明显。这可为大豆异黄酮的综合利用开发提供依据。     

超声波辅助提取葛花总异黄酮及体外抗氧化活性研究

以葛花为原料,总异黄酮得率为响应值,利用超声波辅助法,通过单因素和响应面法优化葛花总异黄酮提取工艺,并评价其体外抗氧化活性。结果显示,葛花总异黄酮超声波辅助提取的最佳条件为:超声时间40 min,超声功率260 W,乙醇浓度74%,超声温度76℃,固液比1∶16(g/mL),总异黄酮得率最高达到(12.35±0.37)mg/g。精制后的葛花总异黄酮对DPPH·、ABTS+·和O2^-·清除率可达到100%,同时具有一定的还原能力。葛花总异黄酮具有较强的体外抗氧化活性。     

二氢杨梅树皮素的抗氧化活性研究

以植物油为研究材料，研究了二氢杨梅树皮素(DMY)的抗油脂氧化的能力；pH、溶剂、铁离子到其抗氧化性的影响。结果表明：DMY具有良好的抗油脂氧化的能力，抗氧化效果优于儿茶素、大豆异黄酮、翟根异黄酮，与TBHO的抗氧化效果相近；在0～0．1％的浓度范围内，其抗氧化效果随浓度增加而增强。DMY掘氧化作用的最适pH范围为4～5；乙醇溶的DMY抗氧化作用优于水溶的DMY的抗氧化作用。铁离子对DMY抗氧化性有一定的抑制作用，但可以通过提高DMY浓度得到改善；因此，DMY作为天然抗氧化剂有很好的开发前景。     

响应面法优化超声辅助离子液体提取黑豆异黄酮及其抗氧化活性研究

以离子液体为提取剂,采用离子液体-超声波辅助提取黑豆异黄酮,考察提取温度、超声时间、[Bmim]Br(1-丁基-3-甲基咪唑溴盐)浓度、料液比对黑豆异黄酮提取率的影响;采用响应曲面法对提取工艺进行优化,与传统提取法进行比较,同时对异黄酮的抗氧化活性进行研究。结果表明,黑豆异黄酮的最佳提取条件为:离子液体浓度为0.75 mol/L、料液比1∶23(g/mL)、提取温度50℃、超声时间40 min。在此条件下黑豆异黄酮的提取率为0.419%,预测值和实际测定值接近,提取率高于传统提取方法;异黄酮对羟自由基的清除效果明显优于VC。响应曲面法优化离子液体-超声波辅助提取黑豆异黄酮稳定、可行。     

不同光照条件下大豆发芽过程中异黄酮含量的比较与抗氧化活性研究

比较了小黄豆和小黑豆在光照和避光条件下发茅后大豆异黄酮的含量和分布,并对其抗氧化活性进行测定分析。小黄豆和小黑豆发茅后,子叶中大豆异黄酮含量均有所降低,芽茎中有所增高。2种大豆在避光条件下发茅,茅茎和子叶中大豆异黄酮的含量均高于在光照条件下发芽。2种光照条件下发芽小黑豆中大豆异黄酮含量均高于小黄豆。小黄豆的抗氧化活性与其大豆异黄酮含量具有相同的变化趋势,而小黑豆的变化趋势不同,小黑豆原豆的抗氧化活性均高于芽茎和子叶。     

大豆异黄酮复合物缓解体力疲劳作用的实验研究

目的　研究大豆异黄酮复合物缓解体力疲劳的作用。方法　雄性ICR小鼠 16 0只 ,体重 18～ 2 2g ,按体重随机分成对照组和 0 13、0 2 7、0 4 0g kgBW3个剂量组 ,每组 4 0只。小鼠经口灌胃给予大豆异黄酮复合物 30d后 ,分别测定负重游泳时间、血清尿素氮、血乳酸及肝糖原含量。结果　大豆异黄酮复合物低、中、高剂量组小鼠负重游泳时间 (4 31、4 4 1、4 86min)与对照组 (2 98min)相比均明显延长 ,小鼠游泳前后血乳酸测定曲线下的面积 (2 1815 9、2 2 2 6 6 2、2 0 5 72 4 )明显低于对照组 (2 4 6 99 2 ) ,中剂量组血清尿素氮含量 (7 4 6mmol L)低于对照组 (8 76mmol L) ,中、高剂量组小鼠静息状态肝糖原水平 (30 0、30 7mg g)明显高于对照组 (2 3 3mg g)。结论　大豆异黄酮复合物具有缓解体力疲劳的作用。     

Lard uptake and its detection in selected food products deep-fried in lard

Analytical methods for the detection of both pork and lard in food products are in great demand for regulatory purposes. Means of identifying food products fried in lard has been investigated in this study. Four fat containing products namely, peanuts, tempeh (fermented soybean cake), chicken and beef were subjected to deep-fat frying using lard as the frying medium. Oils extracted from the control and fried samples were analyzed by gas liquid chromatography (GLC), high performance liquid chromatography (HPLC) and differential scanning calorimetry (DSC). In this way, changes in composition and thermal profiles during frying were examined. Results showed that palmitic acid enrichment factor (PAEF) calculated from GLC analysis of fatty acid methyl esters seems to be a useful parameter in determining lard contamination in all four fried products. With the triglycerol (TG) profiling by HPLC it was possible to detect lard in fried chicken and tempeh products while DSC cooling and heating traces were found to be useful for lard detection in fried tempeh, chicken and beef products.     

Daidzein and genestein contents in tempeh and selected soy products

The total isoflavones in tempeh and selected local soy products was determined. Raw tempeh contained 26 ± 6 mg daidzein (Da) and 28 ± 11 mg genestein (Ge) while fried tempeh contained 35 ± 11 mg Da and 31 ± 11 mg Ge in 100 g (wet basis). Total isoflavone content in 100 g of raw tempeh, based on a dry weight, was 205 ± 56 mg and significantly reduced to 113 ± 41 mg in 100 g of fried tempeh. Tempeh in batter was deep-fried for 30 min which reduced 45% of the total isoflavone content compared to the raw one. Raw tempeh contained the highest total content of isoflavone among the studied local soy products. Total isoflavone content in processed soy foods like egg tofu and home made soybean drink were significantly lower than other soy products studied.     

高温下芝麻素抗氧化性的研究

为开发利用芝麻素天然食品抗氧化剂,系统研究了芝麻素热稳定抗氧化活性。研究结果表明:在高温下,芝麻素具有良好的抗氧化性,对猪油和菜籽油抗氧化效果高于同浓度的对照组,磷酸对芝麻素在猪油中的抗氧化活性有显著的增效作用,并对由金属离子(Cu2 、Fe2 )引起的促氧化作用有明显的抑制效应。     

丹贝异黄酮的提取分离与结构鉴定

从丹贝中分离纯化了 3种异黄酮 ,它们分别是染料木素、大豆黄素、黄豆黄素 ,而未分离到 6 ,7,4’ -三羟基异黄酮。丹贝中异黄酮的组成主要是各种苷元 ,证明丹贝生物活性的提高是由于异黄酮由糖苷水解成苷元所致。同时还发现 ,使用甲醇作溶剂在分离纯化过程中可能使染料木素转变成黄豆黄素     

大豆异黄酮与原花青素在保健酒中的稳定性研究

研究天然植物提取物大豆异黄酮与原花青素在保健酒中的稳定性.以韵酒为研究对象,通过测定化学成分含量和抗氧化活性考察大豆异黄酮与原花青素的变化.在实验考察的四年期间内,韵酒中大豆异黄酮、原花青素的含量及保健酒的抗氧化活性的变化均能够维持在允许范围内.大豆异黄酮与原花青素在保健酒中具有较好的稳定性.     

Sensory Evaluation of Tempeh Produced by Fermentation of Common Beans

A tempeh fermented product was prepared from fresh and hard-to-cook (HTC) common beans with the mold Rhizopus oligosporus. Fresh samples fermented for 0, 24 and 48 hr were used to prepare fried tempeh, atoles and cookies at various substitution levels. Atoles were also prepared with fermented hardened beans. A panel evaluated samples for the sensory variables: appearance, odor, color, flavor, texture, and acceptability. For fried tempeh, flavor and acceptability were the sensory variables most affected by fermentation. Atoles, supplemented with fermented fresh and HTC seeds, had significantly lower (P<0.05) flavor and color than controls, respectively. Interestingly, acceptability of atoles, from both fresh and HTC samples, and of cookies was not significantly different (P>0.05) from the controls.     

Isoflavone profiles,phenol content,and antioxidant activity of soybean seeds as influenced by cultivar and growing location in Ohio

Isoflavone levels and isoflavone chemical composition in soybeans vary between planting locations although the exact factors which control isoflavone biosynthesis are unclear. We compared levels of 12 isoflavones in soybean seeds of six cultivars grown in four different locations in Ohio in 2002 as determined by high‐performance liquid chromatography. Antioxidant activity contained in plant‐based foods can improve food oxidative stability and phenolics and isoflavones have proven active in food systems. Radical scavenging activity was assessed using the 2,2‐diphenyl‐1‐picrylhydrazyl (DPPH) radical. Total phenolics (TPCs) were determined by using Folin–Ciocalteu reagent. Total isoflavones (TIs) varied five‐fold (1573–7710 nmol g^?1) between seeds from the various location–cultivar combinations. One location (Wooster, Ohio) produced seeds containing half the isoflavones as the other locations tested apparently due to poor growing conditions. The cultivars could be divided into two groups based on TI, one having approximately 50% more isoflavones. Surprisingly, across the entire data set, with increasing TI, the proportion of isoflavones accounted for by the daidzein family increased due primarily to malonyl daidzin. DPPH scavenging did not differ significantly by location or cultivar (P > 0.05) and did not correlate with TPC or TI. Profiling soybean isoflavones could help elucidate how isoflavone biosynthesis is regulated and lead to better disease resistance of soybean crops and soy foods with greater health benefits. Copyright © 2007 Society of Chemical Industry     

Optimization of acid hydrolysis conditions for total isoflavones analysis in soybean hypocotyls by using RSM

The optimum hydrolysis conditions of soybean hypocotyls with HCl for a quantitative HPLC determination of total isoflavones (TI) were studied by using response surface methodology (RSM). HCl concentration (HC), hydrolysis time (HT) and reaction temperature (RT) were assumed to be the most important factors affecting hydrolysis for the determination of TI. Optimum hydrolysis conditions for maximizing the determination of TI were: HC=3.42N, HT=205.5 min and RT=44.6°C. The model had a satisfactory coefficient of R² (=0.967) and was verified experimentally. Furthermore, the recovery of individual isoflavones was 97–100% under the optimum hydrolysis conditions. The results suggested that the conditions were mild and useful for maximizing a quantitative HPLC determination of TI in soybean hypocotyls.     

Determination of compounds responsible for tempeh aroma

Tempeh is a fermented food, popular mainly in south-east Asia, but also among vegetarians worldwide. It is produced by fermenting soybean or other beans with Rhizopus strains and usually eaten deep-fried, steamed or roasted. The flavour of tempeh depends upon the fermentation time, beans used and the (eventual) frying process. Our goal was to identify compounds responsible for the unique aroma of fermented and fried soy tempeh. Gas chromatography–olfactometry (GC–O) with the aroma extract dilution analysis (AEDA) approach, was used to determine key odorants after 1 and 5 days of fermentation and subsequent frying. Comprehensive gas chromatography–mass spectrometry (GC × GC–ToF-MS) was used for their quantitation using stable isotope dilution analysis (SIDA) or standard addition (SA) methods. Odour activity values (OAV) were calculated for 19 out of 21 key odorants. Tempeh was fermented for 5 days and fried, and the main aroma compounds were found to be the following: 2-acetyl-1-pyrroline, (FD = 1024, OAV 1380), 2-ethyl-3,5-dimethylpyrazine (FD = 512, OAV 338), dimethyl trisulfide, (FD = 512, OAV 900), methional (FD = 512, OAV 930), 2-methylpropanal (FD = 512, OAV 311) and (E,E)-2,4-decadienal (FD = 512, OAV 455). The frying process induced the increase or appearance of the main key odorants in tempeh.     

不同贮存条件对海藻油氧化稳定性影响

以过氧化值为指标,考察空气、温度、光照等环境条件对海藻油稳定性影响,然后采用Schall烘箱加速氧化法,以POV和DHA含量为指标,通过L9(34)正交试验,从抗氧化剂TBHQ、VE、Vc棕榈酸酯优选海藻油复合抗氧化剂;及研究充N2保护、充N2保护结合添加抗氧化剂对海藻油稳定性影响。结果表明:空气,高温及光照均可显著加速海藻油氧化,降低海藻油稳定性;抗氧化剂TBHQ、VE、Vc棕榈酸酯能明显延缓海藻油氧化,影响顺序为Vc棕榈酸酯TBHQVE,最佳抗氧化剂组合为0.01%Vc棕榈酸酯+0.02%TBHQ+0.50%VE;充N2保护也能提高海藻油氧化稳定性,但效果比最佳复合抗氧化剂为差;充N2保护结合添加抗氧化剂能有效提高海藻油氧化稳定性。