豆豉活性成分的研究进展

对豆豉中大豆异黄酮、大豆低聚糖、大豆蛋白、豆豉溶栓酶以及褐色色素等活性成分的研究进展进行了综述。并对我国豆豉的研究与开发进行了分析和展望。     

永川豆豉传统发酵过程中的大豆异黄酮变化

为了探明永川豆豉在传统发酵过程中大豆异黄酮总含量和构成变化,采用高效液相色谱技术对永川豆豉传统发酵过程中大豆异黄酮总量和构成进行测定。结果表明：永川豆豉在发酵加工过程中大豆异黄酮总含量由发酵起始的3117mg/kg下降到豆豉成熟时的1754mg/kg;大豆异黄酮构成变化显著,游离苷元型大豆异黄酮含量迅速增加由发酵起始的3.2%上升到豆豉成熟时的95.7%,同时结合糖苷型大豆异黄酮含量迅速降低。     

豆豉加工前后营养与活性成分变化的研究

豆豉加工处理可以使豆豉中游离氨基酸、维生素B1、维生素B2、可溶性糖的含量增加;发酵处理基本上不改变豆豉中异黄酮的总含量,而糖苷型大豆异黄酮在β-葡萄糖苷酶的作用下可转化为游离型大豆异黄酮,使游离型大豆异黄酮的含量明显提高。     

浏阳豆豉发酵过程中抗氧化成分及活性变化研究

通过测定大豆异黄酮、总黄酮、总多酚含量的变化,结合发酵过程中浏阳豆豉的抗氧化活性的变化,来探讨浏阳豆豉抗氧化活性变化的机理。结果表明:虽然总黄酮与总大豆异黄酮的含量逐步减少,但发酵初期原料中大豆异黄酮主要为糖苷型(占85.75%),而发酵末期则主要为更具活性的苷元型大豆异黄酮(占81.41%),且总多酚经发酵从2.78 mg/g提升至5.76 mg/g,发酵最后一天(L20)豆豉的总抗氧化能力、DPPH·、·OH、O₂-·清除率分别增加至1088.91 U/g、93.67%、90.24%、88.38%,此外相关性结果表明苷元型大豆异黄酮要比总多酚对豆豉抗氧化活性的影响更大。实验证明发酵有助于大豆中总多酚的增加以及糖苷型大豆异黄酮向苷元型大豆异黄酮转换,这是提高豆豉抗氧化能力及功能性的关键因素之一。     

豆豉营养与保健功能的研究

大豆发酵食品豆豉是我国的特色产品，有很高的营养价值。除含有人们熟悉的优质蛋白质、必需脂肪酸、无机盐及维生素外，天然存在的生理活性成分还包括有大豆异黄酮类、大豆低聚糖、大豆皂甙及大豆磷脂等。     

响应面法优化水豆豉纯种发酵产大豆异黄酮的条件

目的:为了提高水豆豉中大豆异黄酮的最高产量,通过响应面法优化水豆豉纯种发酵产大豆异黄酮的条件。方法:利用前期筛选出来的水豆豉高效发酵菌株进行黄豆发酵,经过单因素实验得到较优的3个水平,以大豆异黄酮含量和感官评价得分为响应值,通过响应面实验获得最优发酵条件。结果:水豆豉的最优发酵条件为发酵温度40℃、发酵时间4d、接菌量1.00%。在此条件下进行发酵,可获得最高大豆异黄酮含量和感官评价得分,分别为881.28mg/kg和74.50分。结论:获得该菌株的最佳发酵条件,为研发高产大豆异黄酮的水豆豉积累了资料。     

日本纳豆与中国豆豉营养功能成分的研究进展

许多研究表明，日本纳豆含有独特的纳豆激酶，具有溶血栓、降血压、防治糖尿病等功能；中国豆豉的加工处理可以使游离氨基酸、维生素B1、维生素B2、可溶性糖的含量增加，可以使糖苷型大豆异黄酮转化为活性更高的游离型大豆异黄酮等，进一步提高了豆豉的营养与保健功能。     

发酵处理对豆豉抗氧化活性影响的研究

发酵处理基本上不改变豆豉中异黄酮的总含量,而糖苷型大豆异黄酮在β-葡萄糖苷酶的作用下部分转化为游离型大豆异黄酮,使游离型大豆异黄酮的含量明显提高;在样品未添加任何抗氧化剂的前提下,通过试验发现豆豉的自身抗氧化性比原料熟黑豆强许多。     

豆豉的风味、活性成分及其功能特性研究进展

豆豉因其独特的风味和广泛的功能特性而成为人们日常饮食的重要组成部分。大豆在发酵过程中,利用微生物分泌的酶系将大豆大分子营养物质水解成氨基酸、肽、有机酸等物质,进而发生一系列生化反应,产生了酯类、酚类、酮类和吡嗪类等风味物质以及大豆苷元型异黄酮、纤溶酶等生物活性物质,使豆豉具有营养和健康优势。文章综述了豆豉的分类及微生物多样性、风味成分和生物活性物质,并介绍了豆豉的抗氧化、降血压、抗骨质疏松、抗血栓、调节肠道健康和预防阿尔兹海默症等其他功能特性,以期为未来豆豉工艺优化和标准化提供理论依据。     

豆豉异黄酮磷脂复合物的制备工艺及其性质研究

以豆豉异黄酮与大豆卵磷脂的复合物复合率为考察指标,采用单因素试验考察了豆豉异黄酮磷脂复合物的最佳制备工艺：以无水乙醇为反应溶剂,异黄酮质量浓度为6.3 mg/mL,异黄酮与磷脂的质量比为1∶1.5,反应温度为50 ℃,反应时间为1.5 h,复合物复合率达86.5%。同时对该复合物的紫外光谱、红外光谱分析和表观油水分配系数等性质进行测定与分析。研究表明,复合物的形成依赖于豆豉异黄酮与卵磷脂某些基团之间的相互作用力,并没有发生化学结构的变化,且复合物的表观油水分配系数有了一定的改善,对豆豉异黄酮的生物有效性和生物利用度的提高具有一定的指导作用。     

Effects of fermentation on the phytochemical composition and antioxidant properties of soy germ

Soy germ is a remarkable source of bioactive phytochemicals offering an interesting alternative as starting ingredient for fermented food. This work aimed to determine whether lactic acid bacteria fermentation of soy germ induces changes on its phytochemical composition. The antioxidant properties of fermented soy germ samples periodically taken during the fermentation process were evaluated and correlated with the concentration and structural modifications of isoflavones, saponins, phytosterols and tocopherols. Fermented soy germ extracts exhibited a higher inhibition effect against the superoxide anion radical, and lesser but significant ferric-reducing and DPPH radical scavenging effects compared with raw soy germ. By comparison to the traditional whole seed-based products, soy germ exhibits higher levels of isoflavones, saponins, phytosterols and tocopherols. All these phytochemicals contributed to the antioxidant capacity of soy germ and were conserved under lactic acid bacteria fermentation.     

中国大豆制品中异黄酮含量测定和分析研究

对中国几种有代表性的大豆制品进行了异黄酮含量测定。测定结果表明 :中国的大豆制品中含有一定量的异黄酮 ,其中非发酵制品中的异黄酮只有极少量以游离形式存在 ,大部分以 β 葡萄糖苷的形式存在 ,主要是黄豆苷 (daidzin)和染料木素 (genistin) ;而在发酵大豆制品中 ,由于酶的作用 ,部分黄豆苷和染料木素转化成黄豆苷原 (daidzein)和染料木因 (genis tein) ,因此 ,游离态的异黄酮比例增加。中国大豆制品中异黄酮含量随大豆品种和加工工艺而异 ,含量范围在 1 1 2 82～ 1 871 6 1 μg/ g ,这个结果表明中国的大豆制品对人体的健康具有重要作用。     

ANTIOXIDANT PROPERTIES OF ETHANOLIC AND METHANOLIC EXTRACTS FROM MONASCUS-FERMENTED SOYBEANS

Soybeans are very common foods in oriental countries used as a meat substitute. Monascus species possess functional components and have been used on traditional fermented food. Solid-state fermentation of the soybean substrate by Monascus species is a new area of investigation. In the present study, methanolic extracts from three samples exhibited better antioxidant activity in the conjugated diene method, reducing power, scavenging ability on 1,1-diphenyl-2-picrylhydrazyl radicals and chelating ability on ferrous ions. Monascus species inoculated onto the soybean substrate contributed higher reducing power, scavenging and chelating abilities and higher amounts of phenol components than uninoculated soybean product. Overall, Monascus- fermented soybeans showed better antioxidant properties and can be developed as a new dietary supplement and functional food.

PRACTICAL APPLICATION

Soybeans and soy products are rich in isoflavones and are very common foods used as a meat substitute in oriental countries. Fungus Monascus has been used as a traditional fermented food and its metabolic products are also utilized as food pigments or biological agents in oriental countries for centuries. Many reporters showed that soy isoflavone aglycones and Monascus spp. metabolite exhibited physiological activities. In addition, previous studies showed a fermentation process using microorganisms to inoculate onto a nonsoluble material that can produce chemicals and enzymes. Therefore, the ethanolic and methanolic extracts from Monascus -fermented soybeans were evaluated for antioxidant properties, and the information obtained would be more valuable than that from soybeans to develop new functional foods.     

高效液相色谱法测定大豆发酵制品中的生物胺

目的从生物胺角度初步探讨大豆发酵制品的食用安全性,为确定大豆发酵制品的推荐安全摄入水平提供初步参考。方法采用柱前衍生高效液相色谱法检测大豆发酵制品中生物胺的含量,以0.4 mol/L高氯酸为提取液,以丹酰氯为衍生试剂,紫外检测波长254 nm。结果样品组分分离及测定结果重现性较好,豆豉、豆酱、酱油3种大豆发酵制品均有部分品牌组胺含量超过危害作用水平(即500 mg/kg),8个样品中有7种超过100 mg/kg,同类不同品牌大豆发酵制品间组胺含量没有明显差别;色胺均未检出;除组胺外,3种大豆发酵制品中尚可能存在2-苯乙胺、腐胺及尸胺。结论大豆发酵制品的色胺未检出,组胺含量较高,大量食用可能影响人体健康。     

Modification of isoflavone profiles in a fermented soy food with almond powder

Isoflavone profiles of a fermented soy food, cheonggukjang, were modified using almond powder. Isoflavones were analyzed by high performance liquid chromatography (HPLC) with an ultraviolet detector. Malonyl derivatives of isoflavones decreased and aglycones of isoflavones increased in samples with almond powder for 48 h. As added, almond powder increased from 0%, 5%, and 10% (w/w), amounts of aglycones increased to 21.11%, 26.63%, and 32.45% for 48 h, respectively. β-Glucosidase activity in 5% and 10% almond added samples was significantly higher than samples without addition of almond (P < 0.05). The content of succinyl daidzin and succinyl genistin, new metabolites from isoflavones, in almond-added cheonggukjang was significantly lower than control samples, implying that β-glucosidase activity from almond affected negatively the formation of succinyl derivatives (P < 0.05). Principal component analysis (PCA) for isoflavone distribution showed that first principal component (PC1) and second principal component (PC2) expressed 64.78% and 22.26% of the data variability, respectively. Biotransformation of isoflavones in any fermented soy foods can be achieved using natural products containing high β-glucosidase activity such as almond. PRACTICAL APPLICATION: The results of this study can help to modify the structural transformation of phytochemicals in any fermented soy foods using natural products. Adjusting the content of almond powder can achieve wanted profiles, for example, high aglycones content. Also, content of metabolites such as succinyl derivatives can be controlled using proper amounts of almond and fermentation time.     

The effect of probiotic‐fermented soy milk on enhancing the NO‐mediated vascular relaxation factors

BACKGROUND: Soy milk is one of the common soy‐based foods in Asia. In this study the effects of soy milk fermented with selected probiotics on nitric oxide (NO)‐mediated vascular relaxation factors in cell model systems were investigated. RESULTS: Soy milk fermented with Lactobacillus plantarum TWK10 or Streptococcus thermophilus BCRC 14085 for 48 h showed a greater transformation of glucoside isoflavones to aglycone isoflavones (P < 0.05). An increase in aglycone isoflavones in ethanol extracts from fermented soy milk stimulated NO production and endothelial NO synthase (eNOS) activity in human umbilical vein endothelial cells. It also had a stimulating effect on superoxide anion scavenging and prostaglandin E₂ production. In addition, it enhanced mRNA expression of the E‐prostanoid 4 receptor in rat thoracic aorta smooth muscle cells. Moreover, a small amount of O induced by water extracts from fermented soy milk at low concentration (1 mg mL^?1) increased the content of calcium ions and activated eNOS, thereby promoting NO production and the coupling state of eNOS. CONCLUSION: Soy milk fermented with selected probiotics promotes the relaxation factors of vascular endothelial cells and can be applied in the development of functional foods. © 2012 Society of Chemical Industry     

Soymilk fermented with Lactobacillus rhamnosus CRL981 ameliorates hyperglycemia,lipid profiles and increases antioxidant enzyme activities in diabetic mice

Interest in soybeans and soy-based products has grown significantly in the last decades due to their reported nutritional and health-promoting effects. In soybean and non-fermented soy foods, isoflavones are predominantly found as glucosides, which must be hydrolyzed in order to exert their documented beneficial effects. The objective of this study was to evaluate the effect of soymilk fermented with Lactobacillus rhamnosus CRL981, a strain that can completely hydrolyze glucoside isoflavones due to its high beta-glucosidase activity. Using a diabetes animal model induced with streptozotocin, it was shown that the fermented soymilk was able to significantly decrease glucose levels, total cholesterol concentrations, triacylglycerols and increase antioxidant enzyme activities compared to animals that received unfermented soymilk. This study clearly shows that the adequate selection of starter cultures could be used to develop novel soy based products intended for the prevention or adjuvant treatment of diseases such as diabetes.     

Stability and Shelf Life of Bioactive Compounds during Food Processing and Storage: Soy Isoflavones

ABSTRACT: During the past several years, the nutrition community has recognized the importance of the nonnutritive components of plant foods. These nonnutritive components are commonly called phytochemicals. One of the most exciting developments in the phytochemicals field is the beneficial biological activity of isoflavones from soy. Benefits include the potential reduced cancer risk, cholesterol homeostasis, and other hormone replacement therapy treatments. Yet, very little attention has been given to the interactions of bioactive phytochemicals with other food ingredients. Various studies demonstrated the loss of soy isoflavones during storage and the effect of processing conditions on specific modifications of soy isoflavones. Beyond apparent 1st-order degradation kinetics, there is a change in the isoflavones profile according to processing and storage conditions. This change in chemical structure is very likely to affect the bioavailability and bioactivity of soy isoflavones. Understanding the reactions that affect soy isoflavones bioactivity will provide a basis for developing food with the beneficial quality of isoflavones. This article presents current information on the stability of soy isoflavones and highlights how these changes may affect their bioavailability and biological activity. Most importantly, the aim of this article is to point out the fact that much more data are required to fully understand the chemistry and the kinetics of isoflavones reaction in model systems and food.     

Simultaneous enhancement of free isoflavone content and antioxidant potential of soybean by fermentation with Aspergillus oryzae

In order to determine the fungal strain and fermentation period which produce the highest antioxidant activity of fermented soy product, soybean was fermented with Aspergillus oryzae NL 5 isolated from Korean traditional meju produced in Sunchang Yeastopia Land in Korea, and was subjected to analyzing isoflavone profiles and assaying antioxidant activity. Antioxidant potential of the samples was evaluated by ferric reducing antioxidant power assay, 2,2'-azinobis (2-ethylbenzthiazoline-6-sulfonic acid) radical scavenging activity and total phenolic contents. In addition, antioxidant assay using fluorescent probes, 2',7'-dichlorofluorescin diacetate and dihydroethidium, in HepG2 cells was conducted for the samples. The results showed that both high isoflavone variety Aga 3 and medium isoflavone variety Daewon of soybean fermented with Asp oryzae NL5 for 4 to 5 d showed the highest increase in free isoflavone contents, together with the highest antioxidant activity. In conclusion, the antioxidant activity of fermented soy was proportional to the concentration of free isoflavones, and was significantly influenced by total isoflavone content of soybean variety and fermentation period. Practical Application: Isoflavone profile and antioxidant capacity of soybean were widely variable during fermentation with Asp oryzae, and thereby it is recommended that meju (or koji) preparation condition, in particular, fermentation time is carefully optimized to maximize the antioxidant capacity of soy products fermented by Asp oryzae.     

Profiling and quantification of isoflavones in soymilk from soy protein isolate using extracted ion chromatography and positive ion fragmentation techniques

Dietary supplements on soy based foods and beverages are increasingly gaining prominence all over the world. In this study, liquid chromatography coupled with positive electrospray ionisation tandem mass spectrometry (LC-ESI-MS) and diode array detection was used for the quantitation and characterisation of isoflavones in fermented and unfermented soymilk made from soy protein isolate SUPRO 590. Bifidobacterium animalis ssp. lactis Bb12 was used for the fermentation of soymilk. The isoflavones were found to produce characteristic radical ions as well as molecules of H₂O, CO₂, a sugar unit, and an alcohol through collision-induced fragmentation. Product ion fragments revealed unique fragmentation pathways for each isoflavone compound. Characteristic fragmentation of different isoflavones were unequivocally identified and differentiated. The occurrence of aldehydes such as pentanal, ethanal and methanal was shown to be specifically linked with isoflavone aglycones, daidzein, genistein and glycitein, respectively. Main glycosides such as genistin, daidzin and glycitin as well as the acetyl-, and malonyl forms also showed respective aglycone ions in their spectra fragmentation. Thus positive ion fragmentation was important in the absolute confirmation of isoflavones and to reveal the occurrence of other related compounds such as aldehydes in soymilk.