Disintegration of solid foods in human stomach

ABSTRACT:  Knowledge of the disintegration of solid foods in human stomach is essential to assess the bioavailability of nutrients in the gastrointestinal (GI) tract. A comprehensive review of food gastric digestion, focusing on disintegration of solid foods, is presented. Most of the research reviewed in this paper is contained in the medical, pharmaceutical, food, and nutritional literature. Stomach physiology is briefly introduced, including composition and rheological properties of gastric contents, stomach wall motility in fed/fasted states, and hydrodynamic and mechanical forces that act on the ingested food. In vivo and in vitro methods used for studying food and drug digestion in GI are summarized. Stomach emptying rate, which controls the rate of absorption of nutrients, is highly related to the disintegration of foods. This topic is highlighted with focus on the important mechanisms and the influence of chemical and physical properties of foods. Future research in this area is identified to increase our fundamental understanding of the food digestion process in the stomach as related to the food composition, material properties such as texture and microstructure, and chemical characteristics. This information is necessary to develop new guidelines for seeking innovative processing methods to manufacture foods specifically targeted for health.     

Food microstructure affects the bioavailability of several nutrients

ABSTRACT:  There is an increased interest in the role that some nutrients may play in preventing or ameliorating the effect of major diseases (for example, some types of cancer, cardiovascular diseases, eye disorders, among others). In this respect, the bioavailability or the proportion of an ingested nutrient that is made available (that is, delivered to the bloodstream) for its intended mode of action is more relevant than the total amount present in the original food. Disruption of the natural matrix or the microstructure created during processing may influence the release, transformation, and subsequent absorption of some nutrients in the digestive tract. Alternatively, extracts of bioactive molecules (for example, nutraceuticals) and beneficial microorganisms may be protected during their transit in the digestive system to the absorption sites by encapsulation in designed matrices. This review summarizes relevant in vivo and in vitro methods used to assess the bioavailability of some nutrients (mostly phytochemicals), types of microstructural changes imparted by processing and during food ingestion that are relevant in matrix-nutrient interactions, and their effect on the bioavailability of selected nutrients.     

甲壳类水产食物致敏原及其分子结构的研究进展

甲壳类水产品是亚洲地区最主要的致敏食物。食物过敏主要由摄入的食品致敏原引起,而食物致敏原的结构不仅与抗原表位的形成有关,也决定了其在食品加工和体内消化过程的稳定性。本文针对甲壳类水产品,首先阐述了甲壳类水产食物过敏及致敏原的研究进展;进一步对甲壳类水产食物致敏原的分子结构及其与致敏性的构效关系展开论述,并基于此提出了致敏原脱敏策略。目前已鉴定的甲壳类水产食物致敏原大部分属于肌动蛋白结合蛋白、磷酸原激酶和EF手型钙离子结合蛋白3个家族。针对不同蛋白质家族致敏原的结构特点,通过食品加工技术消减致敏性或利用分子生物学手段获得低致敏性衍生物都是防控食物过敏的重要途径。但甲壳类水产食物致敏原的结构信息有待完善,其与致敏性的构效关系也仍是未来致敏原研究的重要方向。本文综合阐述了甲壳类水产食物致敏原结构特性及其与致敏性的构效关系,以期为甲壳类水产食物致敏原的系统研究和食品脱敏方法的建立提供思路。     

脂质体外消化过程中氧化评价模型与检测方法研究进展

脂质是人体所需三大营养素之一,其全摄入链的安全和健康特性备受重视。胃肠道内含有羟基、活性氮族等多种促氧化因子,使脂质在胃肠道消化过程中易产生氧化反应。体外模拟消化相比体内消化评价具有耗时短、无伦理问题等优点,是研究脂质胃肠道消化的优选方法。同时,考虑到人体消化道环境的复杂性和脂质的多样性,消化后脂质氧化状态的真实评价也尤为关键。在研究脂质消化过程以及脂质在消化道中的氧化状态时,需要将这些方法整合利用以求对相关问题进行全面性的探索。作者介绍了脂质在体内的消化过程和目前研究脂质常用的体外消化模型,阐述了脂质消化过程中氧化产物的检测方法,对于系统研究特定脂质消化过程中的氧化机理、氧化途径具有重要意义。     

食物基质和胃肠道对经口暴露纳米颗粒物理化学性质和生物效应的影响

食品中纳米颗粒的增加使得其经口暴露于人体的可能性增大。因此,准确评估经口暴露纳米颗粒安全性十分重要。作者综述了食品中最常见纳米颗粒与食物基质、胃肠道的相互作用对纳米颗粒物理化学性质和生物效应影响,为准确评估纳米颗粒安全性提供参考。     

膳食纤维调控胃肠道营养健康研究进展

膳食纤维包括不易消化的碳水化合物和复杂的聚合物木质素,增加膳食纤维的摄入量可以减少胃肠道慢性发病率,该营养物质在食品加工领域和临床研究领域都被广泛应用。本文介绍了膳食纤维的定义及分类,并综述了膳食纤维对人体胃肠道的影响,膳食纤维对肠道微生物的作用及膳食纤维对肠道疾病的影响机制,以为之后膳食纤维在胃肠道营养健康方面的研究及开发提供理论基础。     

油脂组学在人体营养健康研究中的应用进展（网络首发、推荐阅读）

油脂是人体所需重要营养素,其对于维持人体营养健康具有关键作用,但不良的膳食油脂摄入方式将增加罹患慢性代谢类疾病的风险,这已成为当前社会面临的严峻的公共卫生挑战。油脂组学整合了基因组学、转录组学、蛋白质组学、代谢组学和脂质组学等分析方法,已成为解析机体营养与代谢调控机制、构建基于膳食因子功能特性、实现人体精准营养的重要手段。阐述了油脂组学的基本概念及其在油脂营养健康方面的主要研究方法;同时对油脂组学在人体营养健康研究中的应用进展进行了综述,重点聚焦机体营养与代谢调控、肠内营养和肠稳态、以及人体精准营养三个方面。针对当前的研究现状,进一步对油脂组学的未来发展趋势进行了展望,以期为拓展油脂组学在油脂营养与健康方面的应用、提升全民营养水平、促进健康中国建设提供参考。     

Role of polysaccharides in food,digestion, and health

Polysaccharides derived from plant foods are major components of the human diet, with limited contributions of related components from fungal and algal sources. In particular, starch and other storage carbohydrates are the major sources of energy in all diets, while cell wall polysaccharides are the major components of dietary fiber. We review the role of these components in the human diet, including their structure and distribution, their modification during food processing and effects on functional properties, their behavior in the gastrointestinal tract, and their contribution to healthy diets.     

紫菜营养品质及食用价值研究进展

近年来, 随着人们对健康饮食的重视程度逐渐提升, 海藻以其独特的营养保健功能逐渐成为国内外研究人员关注的重点。紫菜作为我国主要的食用藻类之一, 其蛋白质、矿物质和膳食纤维等营养物质含量丰富, 具有较高的食用价值, 且深受消费者的喜爱。因此本文综述了紫菜营养物质的生物可及性及其益生元潜力两方面的食用价值, 探究摄入的紫菜经人体胃肠道消化后其蛋白质、矿物质、脂肪酸和色素等营养物质的消化吸收情况, 以及紫菜中可以抵抗人体胃肠道消化酶作用的多糖和多酚类物质对人体肠道菌群结构的调节作用, 并对未来紫菜的研究及其行业发展方向提出相关建议, 以期为紫菜的营养研究、相关产品开发及其综合利用提供参考和借鉴。     

黄花菜的活性成分、生物活性及加工技术研究进展

黄花菜是一种富含各类营养物质的优质食品原料,具有良好的研究前景与潜在的应用价值。本文对黄花菜中主要营养成分进行了总结,发现干黄花菜是低脂高蛋白矿物质丰富的健康食品。此外,由于活性成分的存在使得黄花菜具有多种有益于人体健康的生物活性。在此基础上对黄花菜的贮藏保鲜与干制技术进行概述,指出可以通过鲜黄花菜的预处理和干黄花菜的干制及包装来提升黄花菜品质。最后介绍了黄花菜目前在食品相关行业中的应用与研究方向,以期为黄花菜生物活性成分的研究、贮藏加工技术、相关功能食品的开发和在其他行业领域的应用提供理论基础。     

Molecular detection of Bifidobacterium animalis DN-173010 in human feces during fermented milk administration

We tested different techniques to detect exogenous bifidobacteria (DN-173010) in feces; genus- and species-specific PCR technique; amplified ribosomal DNA restriction analysis (ARDRA) and fluorescent in situ hybridization (FISH) technique. A significant increase in the number of bifidobacteria in feces was observed during ingestion of fermented milk, and also, we detected a decrease in this number when the ingestion stopped. The number of bifidobacteria enumerated by culturing was 10–100-fold lower than by FISH technique. Bifidobacterium animalis DN-173010 can survive passage through the gastrointestinal tract and was detected viable in human feces. Combination of ARDRA and FISH was a powerful tool to detect exogenous bifidobacteria. The aim of this study is to demonstrate that Bifidobacterium DN-173010 can survive passage through the gastrointestinal tract and be recovered live in human feces. For this purpose, we have assessed different techniques to detect and quantify the number of bifidobacteria following fermented milk supplemented with B. animalis subsp. lactis DN-173010 administration and to confirm that this strain can survive passage through the gastrointestinal tract by recovering viable cells in human feces.     

人工模拟胃肠道模型在食源性致病菌异质性研究中的应用进展

探究食源性致病菌在人体胃肠道环境中的异质性以及与肠道菌群间的相互作用对食源性致病菌的控制和预防具有十分重要的意义。人工模拟胃肠道模型基于人体胃肠道的生理过程,在体外条件下模拟体内的消化吸收情况,可以部分或完全替代活体实验,是研究食源性致病菌异质性以及致病机理的一种重要工具。本文系统综述应用人工模拟胃肠道模型研究食源性致病菌在胃肠道中的耐受、耐药异质性,为研究食源性致病菌在人体胃肠道中的异质性提供理论参考,同时将其与食源性致病菌动物感染模型（体内胃肠道模型）进行比较,综合评价人工模拟胃肠道模型在食源性致病菌异质性研究中的应用,以期为构建更加全面、科学的食品安全风险评估体系提供一定指导。     

Metabolic Fate of Ellagitannins: Implications for Health,and Research Perspectives for Innovative Functional Foods

Consumption of dietary ellagitannins (ETs) has been associated with different health benefits. Nonetheless, ETs are not bioavailable as such and are metabolized in vivo. They are partially converted into ellagic acid (EA) in the upper gastrointestinal (GI) tract, but this first metabolite is also poorly bioavailable. In the lower GI tract, EA and residual ETs are metabolized by gut microbiota to produce urolithins, which, together with their conjugate relatives, persist at relatively high concentrations in plasma and urine for days after ingestion of dietary ETs. Thus, ETs and EA may exert local health benefits on the GI tract but systemic health benefits are more likely to result from urolithins. Cellular models suggest that, at physiological concentration, urolithins are active against chronic degenerative diseases. Health benefits have been proven in animal models and during clinical studies. Even so, the crucial involvement of gut microbiota in ET bioconversion induces important variability of physiological response among humans, giving rise to the concept of high and low urolithin producers. This variability among consumers in obtaining potential health benefits from dietary ETs raises new challenges for the functional food industry. Different research perspectives are discussed to tackle this significant issue for nutritionists, food technologists, and consumers.     

Thermal processing implications on the digestibility of meat,fish and seafood proteins

Thermal processing is an inevitable part of the processing and preparation of meat and meat products for human consumption. However, thermal processing techniques, both commercial and domestic, induce modifications in muscle proteins which can have implications for their digestibility. The nutritive value of muscle proteins is closely related to their digestibility in the gastrointestinal tract and is determined by the end products that it presents in the assimilable form (amino acids and small peptides) for the absorption. The present review examines how different thermal processing techniques, such as sous-vide, microwave, stewing, roasting, boiling, frying, grilling, and steam cooking, affect the digestibility of muscle proteins in the gastrointestinal tract. By altering the functional and structural properties of muscle proteins, thermal processing has the potential to influence the digestibility negatively or positively, depending on the processing conditions. Thermal processes such as sous-vide can induce favourable changes, such as partial unfolding or exposure of cleavage sites, in muscle proteins and improve their digestibility whereas processes such as stewing and roasting can induce unfavourable changes, such as protein aggregation, severe oxidation, cross linking or increased disulfide (S-S) content and decrease the susceptibility of proteins during gastrointestinal digestion. The review examines how the underlying mechanisms of different processing conditions can be translated into higher or lower protein digestibility in detail. This review expands the current understanding of muscle protein digestion and generates knowledge that will be indispensable for optimizing the digestibility of thermally processed muscle foods for maximum nutritional benefits and optimal meal planning.     

食物中蛋白质和碳水化合物对睡眠影响的研究进展

大量研究表明食物中常量营养素蛋白质和碳水化合物对睡眠有重要影响,但不同的研究所得结果不尽相同,因此尚不完全清楚食物中蛋白质和碳水化合物对睡眠究竟有何影响。本文结合国内外相关研究,对蛋白质和碳水化合物对睡眠的具体影响进行综述,发现高碳水化合物低蛋白质的食物可能有助于促进睡眠,改善睡眠质量。本文旨在从膳食营养素角度出发为改善睡眠提供一定的理论指导。     

产气荚膜梭菌在食品中的危害及其控制研究进展

产气荚膜梭菌（Clostridium perfringens）是一种革兰氏阳性厌氧芽孢致病菌，广泛分布于环境、动物以及人类的胃肠道中，因能分解肌肉和结缔组织中的糖类并产出大量气体以及形成荚膜而得名。其对生长环境要求较低，是自然界中常见的致病菌。其芽孢是在环境胁迫（低温、干燥或营养缺乏等）下形成的一种微生物休眠体，具有极强的抗逆性，在食品杀菌过程中很难被灭活，是导致食品腐败变质的重要致病菌。因此，控制产气荚膜梭菌是食品研究领域普遍关注的问题。本文系统概述了产气荚膜梭菌的特性、危害及控制该菌及芽孢污染的物理、化学方法，并阐述了目前控制产气荚膜梭菌研究的热点，以期为进一步定向调控产气荚膜梭菌的危害、提高食品安全性、促进肉制品产业健康发展提供理论指导，对食品加工业具有重要的现实意义和实际应用价值。     

Biomimetic plant foods: Structural design and functionality

BackgroundThe rising number of people living with chronic conditions, such as diabetes and cardiovascular disease, along with the widespread demand for healthier foods have posed significant challenges to the food industry. Plant-based foods, beyond simple nutrition, can provide health-benefiting functionalities within the complex environment of the human gastrointestinal (GI) tract. Biomimetics is defined as taking inspirations from nature to solve problems. Biomimetic plant foods (BPFs) can offer solutions for the future with the design of nature-inspired food structures for improved health and well-being.Scope and approachThis review provides an insight into the assembly of plant food structures and their disassembly in the human GI tract. Their role in controlling the digestive fate of nutrients is elucidated. Recent developments and future perspectives on designing BPFs are also presented and discussed.Key findings and conclusionsPlant foods in nature possess hierarchically self-assembled structures. During processing and GI digestion, these structures are disassembled to enable liberation and assimilation of nutrients and bioactive molecules contained within the food matrix. The assembly and disassembly are linked to a hierarchy of structure in plants within which different levels (molecule, polymer, cell wall, cell, tissue, organ) and their interactions can modulate nutrient bioaccessibility and digestion. Inspired by nature, BPFs can be engineered to deliver in-body functionality. The emerging trend of biomimetics will potentially pave the way for the future of food.     

Development of oral food-grade delivery systems: current knowledge and future challenges

In recent years there has been an increasing interest in the development of new and efficient oral food delivery systems as tools to prevent disease and promote human health and well-being. Such vehicles are sought to protect bioactive ingredients added to food while controlling and targeting their release as they pass through the human gastrointestinal tract (GIT). This review aims to summarize the key concepts of food delivery systems, their characterization and evaluation. Particularly, evaluation of their performance within the human GIT is discussed. To this end an overview of several in vivo and in vitro methods currently applied for the study of such systems is given. Although considered to be still in its infancy, this promising field of research is likely to infiltrate into real products through rational design. In order for such efforts to materialize into real products some challenges still need to be met and are discussed herein. Overall, it seems that adopting a comprehensive pharmacological approach and relevant cutting edge tools are likely to facilitate innovations and help elucidate and perhaps tailor delivery systems' behavior in the human GIT.     

Evidence against dietary advanced glycation endproducts being a risk to human health

In vivo, advanced glycation endproducts (AGEs) are linked to various diseases, particularly those associated with diabetes. AGEs are also formed when many foods are thermally processed. The extent to which dietary AGEs are absorbed by the gastrointestinal (GI) tract and their possible role in the onset and promotion of disease are currently of considerable interest. This paper reviews information that supports the argument that dietary AGEs are not a risk to human health.