大豆异黄酮与肠道微生物相互作用研究进展

膳食摄入大豆异黄酮与人体健康有密切的关系。大豆异黄酮糖苷组分与肠道菌群相互作用可产生生物活性和生物可利用度显著提高的新型微生物转化物,促进大豆异黄酮生理活性充分发挥。同时,大豆异黄酮通过调控肠道菌群结构影响结肠中的微生物酶活性,改变结肠菌群代谢能力。本文将对大豆异黄酮与肠道微生物的相互作用进行综述,重点阐述肠道微生物对大豆异黄酮的生物转化作用、大豆异黄酮对肠道微生物及其酶活性的调控作用以及大豆异黄酮及其肠道转化产物对健康的作用。以期为膳食组分和肠道菌群相互作用促进人体健康研究领域提供理论参考。     

Critical Issues in R&D of Soy Isoflavone-enriched Foods and Dietary Supplements

ABSTRACT: Increasing consumer awareness of soy as a healthy food ingredient has led to a tremendous growth in sales of soy isoflavone‐enriched foods and dietary supplements in the past 3 y. Because of their weak estrogenic activity, isoflavones are believed to have preventive effects for several hormone‐dependent diseases. This article discusses some critical issues to be considered in any R&D program of novel soy and isoflavone products for the healthy‐food market, such as (1) Which isoflavone compounds should be in the product? (2) Which individual isoflavones are the most beneficial ones? (3) Can certain isoflavone groups be targeted to specific disease prevention goals? (4) Are there any safety concerns in isoflavone consumption? (5) How are isoflavones affected by thermal processing and storage? (6) How should isoflavones be analyzed? These questions may affect the choice of isoflavone source, processing conditions, quality control procedures, and marketing considerations.     

Digestion and bioavailability of bioactive phytochemicals

There are many scientific reports on determination of the content and biological activity of compounds found in food. However, these analyses are not sufficient to determine their effect on the human body. During digestion of food ingredients, many changes can modify their structure and this may affect their absorption and bioactivity. Many phenolic aglycones are hydrophilic and can be absorbed through biological membranes by diffusion. However, most polyphenols occur in the glycosidic form, which undoubtedly affects their absorption in the intestine. Oligopeptides are also absorbable via secondary active transport but based on the hydrogen ion gradient or with transporter PepT1. The bioavailability of phytochemicals is determined by their molecular weight or chemical structure and the food matrix. Accordingly, the aim of this work was to present the novel scientific reports related to the influence the many factors on digestibility, bioaccessibility and activity of selected bioactive compounds of plant origin.     

Intermolecular interactions in phytochemical model systems studied by NMR diffusion measurements

Novel functional foods, such as tomato juice with soy, represent a new strategy to increase consumption of health promoting ingredients and phytochemicals. Interactions between soy protein, isoflavones, and tomato carotenoids could impact the bioaccessibility and bioavailability of individual phytochemicals. The primary objective of this study was to assess possible interactions between daidzein and daidzin, soy protein and carotenoids using proton one-dimensional and two-dimensional pulsed field gradient nuclear magnetic resonance spectroscopy experiments.     

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.     

Interactions between phytochemicals from fruits and vegetables: Effects on bioactivities and bioavailability

The combinations of two or more phytochemicals bring about changes in the ultimate biological effects and/or the bioavailability of each component. A number of mixtures of pure bioactive compounds or phytochemical-containing plant extracts provide synergy with regard to antioxidant status, anti-inflammation, anti-cancer and chemoprevention of several oxidative stress and metabolic disorders in vitro. The biological activities of food phytochemicals depend upon their bioaccessibility and bioavailability which can be affected by the presence of other food components including other bioactive constituents. The interactions between phytochemicals during intestinal absorption could result in changes in the bioavailability of the compounds, which in turn affects the intensity of their bioactivities. This paper provides an overview of combined biological effects of phytochemical mixtures derived from fruits and vegetables with a focus on anti-oxidative, anti-inflammatory and anti-carcinogenic activities. The bioavailability impairment or enhancement caused by the co-consumption of dietary phytochemicals is also discussed. Finally, research gaps for future studies on phytochemical interactions are identified.     

Bioavailability of glycitein relatively to other soy isoflavones in healthy young Caucasian men

Glycitein is a Selective Estradiol Receptor Modulator (SERM) from soy. The study reports plasma bioavailability and urine excretion of glycitein compared to other soy isoflavones after a unique intake of food supplement based on soy germ containing 55.24 mg isoflavones. Eighteen plasma and urinary sampling profiles collected over 48 h from healthy young Caucasian men were analysed using specific ELISAs. Eight profiles contained equol. Glycitein T_max, C_max, AUC_0→24h and T_½ in plasma were calculated. Urine T_max, % of excretion at 24 h and clearance were assessed. Glycitein is one of the best absorbed flavonoids. Plasma steady-state level can be achieved by several intakes a day. Glycitein bioavailability is similar to that of daidzein and its urinary excretion is significantly higher than that of genistein. Equol does not affect glycitein bioavailability. Knowing glycitein bioavailability in man is essential for the development of soy-germ-based food supplements for health applications.     

Lycopene: Isomerization Effects on Bioavailability and Bioactivity Properties

Lycopene cis-isomers have shown to be more bioavailable and bioactive than the naturally occurring all-trans-isomer. During food processing, lycopene undergoes geometrical isomerization, increasing the proportion of cis-isomers. However, lycopene tends to retro-isomerize during food storage. Because the stability, bioavailability, and distribution of lycopene isomers are physiochemical characteristics critical for health benefits, it is essential to preserve these properties in food products containing lycopene isomers.

The objective of this article is to review thermal and nonthermal technologies available for lycopene geometrical isomerization with a focus on the stability, bioavailability, and bioactivity of lycopene isomers.     

Content and Profile of Isoflavones in Soy-Based Foods as a Function of the Production Process

Soy has been traditionally incorporated in diet as processed foods, such as soymilk, tofu, miso, tempeh, etc., and the consumption is commonly associated with a reduction of the development of chronic diseases due to their antioxidant, anti-inflammatory, and anti-allergic properties, among others. Many of the health benefits of soy have been attributed to isoflavones. They comprise a group of naturally occurring flavonoids consisting of heterocyclic phenols. Soy contains three types of isoflavones in four chemical forms: the aglycones daidzein, genistein, and glycitein; the β-glucosides daidzin, genistin, and glycitin; their 6″-O-malonyl-β-glucosides (6OMalGlc); and their 6″-O-acetyl-β-glucosides (6OAcGlc) conjugates. Industrial processing methods of soy-based food products commonly lead to the loss of isoflavones through removal of undesirable fractions. On the other hand, isoflavones can be transformed into different conjugates, which may have significant effects on the food texture and on the bioavailability and pharmacokinetics of the isoflavones. This article reviews the effect of a number of soybean processing treatments on the isoflavone content and profile. The preparation and manufacturing of different soy-based food and food ingredients, fermented and non-fermented, has been analyzed in terms of content and distribution of the three major isoflavone derivatives, daidzein, genistein, and glycitein, and their respective conjugates.     

食品基质及加工方式对多酚生物利用度影响的研究进展

酚类化合物是植物性食品中的重要成分,具有多种功能活性,但因其生物利用度低,不能在体内完全发挥其生物活性。因此寻找到一条有效的途径来提高其生物利用率非常必要。本文综述了多糖、蛋白质、脂质三种食品基质及不同加工方式对多酚生物利用度的影响,以期为食品加工中提高多酚生物利用度提供借鉴和思考。     

Functional and Edible Uses of Soy Protein Products

ABSTRACT: Consumers are becoming increasingly interested in healthful foods and are open to soy protein ingredients. Soybeans as food are very versatile and a rich source of essential nutrients. They are also an excellent source of good‐quality protein, comparable to other protein foods, and suitable for all ages. Adverse nutritional and other undesirable effects followed by the consumption of raw soybean meal have been attributed to the presence of endogenous inhibitors of digestive enzymes and lectins, as well as poor digestibility. To improve the nutritional quality of soy foods, inhibitors and lectins are generally inactivated by heat or eliminated by fractionation during food processing. Soybeans provide an alternative source of protein for people who are allergic to milk protein. Soy protein is highly digestible (92% to 100%) and contains all essential amino acids. Although relatively low in methionine, it is a good source of lysine. Soy‐protein products contain a high concentration of isoflavones, up to 1 g/kg. Increased acceptance of soy proteins is due to unmatched qualities like good functional properties in food applications, high nutritional quality, abundance, availability, and low cost. At present the various forms of soy proteins are primarily utilized for their functional effects rather than their nutritional properties. This article summarizes the integrated overview of the widely available, scattered information about the nutritional and functional uses of the soy proteins when applied in food systems and intends to present the most current knowledge with an interest to stimulate further research to optimize their beneficial effects.     

INFLUENCE OF HEAT TREATMENT AND GRAIN GERMINATION ON THE ISOFLAVONE PROFILE OF SOY MILK

Soy foods have attracted much attention for their possible effects on human health because of their phytochemical content, mainly isoflavones. Twelve forms of isoflavones have been identified in soybeans and soy products. Technological processes like heat treatment or fermentation can change the isoflavone profile of soy products. In this study, the effects of heat treatment and grain germination on isoflavone profile of soy milk prepared from BRS 213 soybean variety were evaluated. Isoflavone forms were separated and quantified by reversed‐phase high‐performance liquid chromatography. Heat treatment by autoclaving for 5 min did not affect the total isoflavone content, but led to a 90% decrease in malonyl forms, whereas β‐glycosides increased by 70%. Autoclaving for 15 min led to a 20% loss of total isoflavones. Germination for 3 days did not change the total isoflavone content, but changed the distribution profile (15% increase of malonyl forms and 30% decrease of β‐glycosides). Germination for 7 days increased the bioavailability of aglycone isoflavones in soy milk by seven times.     

Apoptotic effects of cooked and in vitro digested soy on human prostate cancer cells

Previous laboratory and animal studies reported that soy isoflavones were major bioactive compounds in soy to exert chemoprotection of prostate cancer. However, these studies cannot reflect the realistic effects that soy may induce through diets, and little is known about the bioavailability of isoflavones from whole soy food and their bioactivities after cooking and digestion. In this study, cooking and in vitro digestion were used to prepare soy extracts and the effects of cooking and digestion on the isoflavone contents and bioactivities of the whole soy extracts were examined. The cooking procedure generally increased the amount of daidzin, genistin and daidzein, but decreased that of genistein. Digestion process significantly lowered contents of daidzin and genistin in 60min cooked sample, while increased the contents of daidzin and daidzein and decreased the content of genistein in the uncooked sample. Antioxidant activities of soy extracts increased after cooking and in vitro digestion, while no consistent increase of the four soy isoflavones was determined. The apoptotic effects of soy extracts on both LNCaP and C4-2B cells were generally in a dose-dependent manner. Compared to purified single isoflavones, cooked and digested soy were more effective on induction of prostate cancer cell apoptosis, which indicated synergistic interactions between various bioactive compounds in the whole soy.     

大豆糖蜜综合利用

该文阐述对大豆糖蜜综合利用,主要介绍以大豆糖蜜作为发酵原料,从大豆糖蜜中分别提取异黄酮、低聚糖和皂甙,及对大豆植物化学成分应用。     

加工和贮藏对果蔬营养成分变化及抗氧化活性影响的研究进展

水果和蔬菜是维生素、非维生素植物化学物质和抗氧化活性的重要来源,因此膳食指南推荐人们摄入足够多的水果和蔬菜,但是这里并没有区分是新鲜果蔬还是加工过的果蔬。然而,人们消费的大部分果蔬都是加工过的,与同样的新鲜果蔬相比,它们的营养物质、功能性成分和抗氧化活性或许不同。讨论了不同罐装、烹调、常温和低温贮藏以及冻藏等贮藏和加工方式对果蔬中维生素、非维生素植物化学物质和抗氧化活性的影响。大量研究表明,加工和贮藏造成了大多数种类果蔬植物化学物质和抗氧化活性的损失。这些信息将有助于指导人们使用贮藏和加工过的水果和蔬菜。     

Physicochemical and in vitro digestion properties of soy isoflavones loaded whey protein nanoparticles using a pH-driven method

Soy isoflavones are widely used as a dietary supplement. However, the bioavailability of soy isoflavones is low due to the poor water solubility. Whey protein is an excellent biopolymer to encapsulate functional ingredients. In this study, soy isoflavones loaded whey protein nanoparticles were prepared using a pH-driven method. The physicochemical properties and in vitro digestion properties of the nanoparticles were investigated. The results showed that the physicochemical properties of nanoparticles were regulated by the mass ratios of soy isoflavones to whey proteins. Hydrogen bonding and hydrophobic interactions were confirmed in generating soy isoflavones loaded nanoparticles, which modified the thermal stability and secondary structure of whey proteins. The nanoparticles could pass through simulated gastric digestion to deliver soy isoflavones into the intestinal tract, responsible for the increased digestion stability and bioaccessibility of soy isoflavones. Moreover, the controlled release of soy isoflavones from nanoparticles can be achieved with a mechanism of non-Fickian diffusion. This study may provide useful information about the utilization of soy isoflavones loaded whey protein nanoparticles to develop functional foods.     

Factors influencing levels of phytochemicals in selected fruit and vegetables during pre- and post-harvest food processing operations

Phytochemicals are important natural bioactive compounds of fruit and vegetables and are widely recognised for their nutraceutical effects and health benefits. This review analyses different factors influencing the level of phytochemicals in selected fruit and vegetables at different processing stages in the production chain. The level of phytochemicals present in fruit and vegetables may vary within and across cultivars. Available literature correlates the level of phytochemicals with many factors including cultivar type, environmental and agronomic conditions, harvest and food processing operations, and storage factors. The optimisation of food processing and storage factors is an essential step to reduce the degradation of phytochemicals for potential health benefits. Cultivar selection and maturity at harvest may be critical for food processors to maintain high levels of phytochemicals in fruit and vegetables.     

Soy Bioactive Components in Functional Perspective: A Review

Functional foods are the focus of attraction for well-being. The healthy living of Asians may be attributed to a diet enriched with soy isoflavones viz. genistein and daidzein which fills the gap of proteinaceous diet in vegetarians. Several factors, such as administration, dosage, metabolism, ingestion of other pharmacological substances, type of estrogen receptors, and presence or absence of endogenous estrogen, affect the activities and bioavailability of isoflavones. The mode of therapeutic action could be either through the stimulation of estrogen receptors or by the non-involvement of estrogen receptors. Soy, due to its isoflavones content, serves as a balanced and remedial substitute in combating various lifestyle disorders, like cancer prevention, by interruption of the breakdown of extracellular matrix that surrounds growing vessels and tumors, lowering of lipid and blood insulin levels by regulating lipid and glucose metabolism, alleviation of menopausal symptoms, and osteoprotective effects by modulating estrogen receptors, thus acting as a safer switch to hormone replacement therapy, anti-hypertensive effect which may also contribute to cardioprotective, anti-oxidative effect, regulation of cognitive functions, and many others. Therefore, it could be regarded as a valuable therapeutics. However, since soy isoflavones also act as endocrine disruptors, they also possess some negative effects. Concerns have been raised in relation to thyroid function abnormality. In view of the previously mentioned facts an attempt has been made to review the literature available on both beneficial as well as deleterious role of isoflavones, soy derived bioactive compounds.     

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.     

Technologies for enhancement of bioactive components and potential health benefits of cereal and cereal-based foods: Research advances and application challenges

Cereal grains are a major source of human food and their production has steadily been increased during the last several decades to meet the demand of our increasing world population. The modernized society and the expansion of the cereal food industry created a need for highly efficient processing technologies, especially flour production. Earlier scientific research efforts have led to the invention of the modern steel roller mill, and the refined flour of wheat has become a basic component in most of cereal-based foods such as breads and pastries because of the unique functionality of wheat protein. On the other hand, epidemiological studies have found that consumption of whole cereal grains was health beneficial. The health benefit of whole cereal grain is attributed to the combined effects of micronutrients, phytochemicals, and dietary fibre, which are mainly located in the outer bran layer and the germ. However, the removal of bran and germ from cereal grains during polishing and milling results in refined flour and food products with lower bioactive compounds and dietary fibre contents than those from whole grain. Also, the level of bioactive compounds in cereal food is influenced by other food preparation procedures such as baking, cooking, extrusion, and puffing. Therefore, food scientists and nutritionists are searching for strategies and processing technologies to enhance the content and bioavailability of nutrients, bioactive compounds, and dietary fibre of cereal foods. The objective of this article was to review the research advances on technologies for the enhancement of bioactive compounds and dietary fibre contents of cereal and cereal-based foods. Bioactivities or biological effects of enhanced cereal and cereal-based foods are presented. Challenges facing the application of the proposed technologies in the food industry are also discussed.