食物基质及脂质分子结构对体内消化吸收的影响机制

脂质在人类饮食中占有重要地位,既可促进身体健康又可能成为疾病的来源。不同类型脂质的存在提升了食品的风味、感官评价,在人们对食物的可接受性方面起积极的作用。目前对于脂质及其应用的研究中很少考虑食物基质或脂质对人类消化吸收过程产生的影响,这些影响可能超出摄入脂肪的种类或数量的重要性。本文阐明脂质经口腔、胃及小肠的消化过程,以及脂肪酸分子在小肠内的分子吸收机制,总结脂质的组成、食物结构及蛋白质和膳食纤维等组分对脂质消化吸收的影响,为研发功能结构脂或评估天然及重组脂质对人类健康的影响提供参考。     

蛋白质基于调节肠道微生物群的健康作用研究进展

肠道微生物群被认为是连接膳食和人体健康的重要桥梁,其生态系统的改变可能会对宿主健康造成影响。蛋白质是人类膳食营养的重要组成部分,根据来源不同,其营养特性存在差异。由于不同来源膳食蛋白的氨基酸组成结构以及消化特性的不同,为肠道中的微生物群提供了不同的代谢底物,导致微生物群的组成结构及代谢特性产生差异,进而不同程度地影响宿主健康。现有报道显示,不同来源的膳食蛋白质会以肠道菌群为介导对机体健康造成不同的影响。该文比较了不同来源蛋白质的氨基酸组成及消化利用情况,分析了其对肠道微生物群的调节作用,并分析其通过调控肠道微生物群影响健康的机理,以期更好地认识与了解膳食蛋白-肠道菌群相互作用以调节机体健康的作用差异,为科学膳食以促进健康提供有益参考。     

膳食脂质肠道消化及吸收的研究进展

膳食脂质作为人类生活中一种必不可少的营养物质来源，为机体提供所需的必需脂肪酸和能量，维持人体正常的生理活动，其中肠道作为脂质最主要的消化场所及特定吸收场所，发挥了重要的作用。该研究在基于脂质肠道消化途径的基础上，从脂质自身形态、蛋白质与脂质相互作用下的形态、脂质构型变化、胆汁盐分泌、胰脂肪酶以及共脂肪酶等多角度论述了影响脂质肠道消化的主要因素，分析了影响脂质消化关键行为的界面作用，从转运因子调节、分子吸收路径以及肠道微生物间接调控吸收三个方面阐述了膳食脂质的肠道吸收机制，为深入开展膳食脂质的功能化修饰、高值化利用、创新性研发提供了理论依据。     

魔芋膳食纤维对油脂体外消化特性的影响

向油脂乳液中加入一定量魔芋膳食纤维，采用pH-stat法模拟油脂体外消化过程，考察魔芋膳食纤维对乳液在胃肠道中消化特性的影响，并研究乳液消化前后有效粒径、粒径分布、Zeta电位和微观结构的变化。结果表明，魔芋膳食纤维对乳液消化特性和消化前后理化性质产生显著性影响。随着纤维含量增加，乳液初始消化速率和最终消化程度均减小，含0.5%(质量分数)魔芋膳食纤维的乳液经胰脂肪酶消化120 min后脂肪酸释放率仅为14.84%;乳液粒径在体外消化的不同阶段逐渐增大，且同一消化阶段随纤维添加量增加而增大；肠消化后Zeta电位绝对值均大于40 mV,脂滴不稳定，发生聚集。脂肪乳液中脂质的最终消化率随体系中纤维添加量的增加而降低，该研究结果对胃肠道中脂质消化的控制及低热量功能食品的开发具有重要意义。     

胃肠道消化过程中脂质氧化的影响因素、健康危害及控制研究进展

研究证实,油脂和富含脂质的食品极易在胃肠道消化过程中发生氧化反应,产生的丙二醛、4-羟基-2-己烯醛(4-HHE)等氧化产物能够对机体造成健康危害。本文对胃肠道消化过程中脂质氧化反应的影响因素、健康危害及植物多酚、类黑精等食品组分干预作用等方面的研究进展进行综述,以期为通过改善膳食结构等途径减少胃肠道消化过程中脂质氧化反应造成的健康危害提供参考。     

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。     

膳食脂质-过敏原互作的研究进展

随着全球过敏人群数量逐年升高,食物过敏已成为一个重要的公共卫生问题。脂质是食物的重要组成成分,越来越多的研究表明,膳食脂质的过量摄入能够增强食物过敏原的致敏特性,增加人群患食物过敏的机率。本文主要从膳食脂质与食物过敏原的关系出发,阐述了膳食脂质影响食物过敏的具体途径及高脂饮食对食物过敏的影响,归纳总结了近10 年来文献中报道的具有膳食脂质结合能力的食物过敏原种类和参与食物致敏过程的脂质种类,以期为食物过敏的预防及治疗提供新的方向。     

膳食蛋白、机体抗氧化调节与健康的关系研究进展

膳食蛋白为机体提供必需氨基酸,还具有广泛的生理功能。膳食蛋白的消化代谢过程中,机体细胞会产生活性氧。活性氧积累可能引发氧化及衰老。细胞中的抗氧化蛋白——硫氧还蛋白、谷氧还蛋白及其他抗氧化酶等共同组成抗氧化系统,抵御活性氧,减少有害物生成。本文综合介绍不同来源的膳食蛋白与相应的抗氧化调节对机体健康的影响,以及活性氧代谢过程中两种抗氧化蛋白的调控作用,结合体内其他抗氧化指标,从而更好地认识不同膳食蛋白的代谢差异,指导个人膳食与健康。     

乳甘油三酯的组成结构及其消化吸收和代谢特性

甘油三酯(triacylglycerols,TAGs)是膳食中最重要的脂质成分,不仅为人体提供能量同时也是多种必需脂肪酸的重要来源。甘油三酯的消化、吸收和代谢受到多种因素的影响。大量研究结果证实除脂肪酸的组成以外,甘油三酯的组成和结构对脂肪酸的吸收和代谢也有显著的影响。乳甘油三酯与其他膳食脂肪相比具有特殊的组成和结构,这些特异性使得乳甘油三酯具有许多特殊的生理和营养学功能。本文详细阐述了人乳、牛乳和山羊乳甘油三酯的结构特征,甘油三酯消化、吸收和脂肪酸代谢过程,以及甘油三酯分子内结构对其代谢的作用的影响,以期为甘油三酯代谢、营养及功能特性研究提供参考。     

影响淀粉消化的内外因素

淀粉作为人类膳食能量的主要来源之一,在人体内的消化吸收特性直接影响其营养价值和生理功能的发挥。由于淀粉来源及自身结构的不同,食品中其它组分的存在,以及食品加工过程的影响,淀粉在机体内的消化特性千差万别。本文综述了近年来国内外关于淀粉消化特性的研究进展,重点介绍影响淀粉消化的内在因素（淀粉自身结构、食物中的其它组分）和外在因素（物理、化学、生物）,并对淀粉消化性的调控进行展望,以期为慢消化或抗消化淀粉质食品的开发提供理论参考。     

胆盐理化性质及其对脂质消化的 影响机制研究进展

胆盐（BS）是胃肠道中的生物表面活性剂,在脂质消化过程中发挥着至关重要的作用。BS特殊的结构组成使之拥有不同于经典表面活性剂的理化性质,例如竞争性吸附和自组装形成胶束的行为,都参与了体内脂肪分解的过程。首先简要介绍了脂质在人体中消化吸收的过程和BS的基本性质,然后进一步阐述了BS影响脂质消化的作用机制,最后综述了近年来BS与肠道中蛋白质、脂质及其他外源食品组分相互作用的研究进展。探究BS在脂质消化中的角色,可以加深对脂质消化机制的理解,同时也可以通过调节脂质消化过程起到防治肥胖症等相关疾病的作用,还能基于BS的特殊性质开发新的载药系统。     

Food lipid oxidation under gastrointestinal digestion conditions: A review

Abstract

Unravelling the relationship between food and health requires a more in-depth knowledge of the various changes occurring in the gastrointestinal tract during digestion and which may ultimately affect the nutritional quality and safety of ingested food lipids before absorption into the bloodstream. In this context, this review deals with the oxidation process of food lipids under digestive conditions and the studies carried out on this topic using different digestion models: in vitro, in vivo or ex vivo, static or dynamic, and including one, two and/or three digestive phases (oral, gastric and duodenal). These studies have contributed to clarifying the occurrence and extent of lipid degradation under such a particular environment, many of them also highlighting the factors affecting the advance or delay of the oxidation of dietary lipids during digestion, like: food lipid content, unsaturation degree and initial oxidative status; the presence in the food bolus of compounds showing antioxidant activity (polyphenols, tocopherols…) either added or naturally present; the presence in the food bolus of proteins (including iron or not); food technological or culinary processings (salting, smoking, cooking…), among others. Likewise, the methodologies employed to study lipid oxidation under digestive conditions are also summarized and future research perspectives are discussed.     

粮油制品蛋白氧化对肠道健康影响的研究进展

在粮油原料及其制品的储运和加工过程中,脂质在内源脂肪水解酶和脂肪氧化酶的催化下发生水解、氧化。脂质氧化产物可诱导蛋白质氧化,导致蛋白质结构发生共价交联,使得蛋白质难以被机体消化,从而影响肠道微生物组成以及肠道屏障功能。本文首先分析了粮油原料及其制品在储运和加工过程中的氧化应激环境,随后介绍了蛋白质氧化对蛋白质结构特征和消化性质的影响,最后探讨了蛋白质氧化对肠道微生物以及肠道健康的可能影响,以期对摄食氧化蛋白质对肠道健康影响的研究提供一定理论参考,为安全合理有效开发蛋白质资源提供理论依据。     

Fat digestion and absorption in spice‐pretreated rats

BACKGROUND: A few common spices are known to stimulate secretion of bile with higher amount of bile acids which play a major role in digestion and absorption of dietary lipids. It would be appropriate to verify if these spices enable efficient digestion and absorption during high‐fat intake. In this context, dietary ginger (0.05%), piperine (0.02%), capsaicin (0.015%), and curcumin (0.5%) were examined for their influence on bile secretion, digestive enzymes of pancreas and absorption of dietary fat in high‐fat (30%) fed Wistar rats for 8 weeks. RESULTS: These spices enhanced the activity of pancreatic lipase, amylase, trypsin and chymotrypsin by 22‐57%, 32‐51%, 63‐81% and 12‐38%, respectively. Dietary intake of spices along with high‐fat enhanced fat absorption. These dietary spices increased bile secretion with higher bile acid content. Stimulation of lipid mobilisation from adipose tissue was suggested by the decrease in perirenal adipose tissue weight by dietary capsaicin and piperine. This was also accompanied by prevention of the accumulation of triglyceride in liver and serum in high‐fat fed rats. Activities of key lipogenic enzymes in liver were reduced which was accompanied by an increased activity of hormone‐sensitive lipase. CONCLUSION: Thus, dietary ginger and other spice compounds enhance fat digestion and absorption in high‐fat fed situation through enhanced secretion of bile salts and a stimulation of the activity pancreatic lipase. At the same time, the energy expenditure is facilitated by these spices to prevent the accumulation of absorbed fat. Copyright © 2011 Society of Chemical Industry     

The Role of Dietary Phenolic Compounds in Protein Digestion and Processing Technologies to Improve Their Antinutritive Properties

Digestion is the key step for delivering nutrients and bioactive substances to the body. The way different food components interact with each other and with digestive enzymes can modify the digestion process and affect human health. Understanding how food components interact during digestion is essential for the rational design of functional food products. Plant polyphenols have gained much attention for the bioactive roles they play in the human body. However, their strong beneficial effects on human health have also been associated with a negative impact on the digestion process. Due to the generally low absorption of phenolic compounds after food intake, most of the consumed polyphenols remain in the gastrointestinal tract, where they then can exert inhibitory effects on enzymes involved in the degradation of saccharides, lipids, and proteins. While the inhibitory effects of phenolics on the digestion of energy‐rich food components (saccharides and lipids) may be regarded as beneficial, primarily in weight‐control diets, their inhibitory effects on the digestion of proteins are not desirable for the reason of reduced utilization of amino acids. The effect of polyphenols on protein digestion is reviewed in this article, with an emphasis on food processing methods to improve the antinutritive properties of polyphenols.     

Estimation of dietary intake of melanoidins from coffee and bread

Melanoidins are defined as polymeric high molecular weight, brown-coloured Maillard reaction end-products, containing nitrogen. They escape digestion and pass through the upper gastrointestinal tract and can interact with the different microbial species present in the colon. Major dietary sources of melanoidins are coffee and bread crust. Both coffee and bread crust melanoidins can be fermented by the human hindgut microflora thus sharing some of the properties attributed to dietary fibre. Despite the emerging positive physiological properties of such dietary constituents their intake has not been estimated yet. To this aim melanoidin content in different type of coffee brews, bread and dry biscuits was determined by sequential ultrafiltration and enzymatic digestion. Despite some drawbacks and limiting steps in the calculation, such as the lack of a reference material, an educated guess on the dietary intake of melanoidins has been put forward. Data indicated that the intake of coffee melanoidins ranged between 0.5 to 2.0 g per day for moderate and heavy consumers, respectively. For bread and dry biscuits an intake in the ranges of 1.8-15.0 and 3.2-8.5 g per day has been calculated. These figures suggest that a realistic estimation of melanoidins dietary intake for general population would be close to 10 g per day considering all the possible alimentary sources.     

SCREENING OF RESISTANT TRIACYLGLYCEROLS TO THE PANCREATIC LIPASE AND THEIR POTENTIALITIES AS A DIGESTIVE RETARDANT

A gradual retarding of lipid digestion and absorption might contribute to preventing the visceral fat accumulation and obesity in humans. The lipolysis rates of different triacylglycerols (TAGs) by pancreatic lipase in vitro were studied in order to find suitable components as a retardant for lipolysis. Several TAGs containing longer acyl chains than stearic acid or containing unsaturated fatty acids whose double bonds are located closely to the carboxyl group like petroserinic and γ-linolenic acid showed significantly lower lipolysis rates as compared with triolein (OOO) control. Most of these resistant TAGs contributed to decelerating the lipolysis rate when replaced at 10% into the OOO control. Especially, 1-behenoyl-2,3-dioleoyl- rac -glycerol (BOO) was comprehensively thought to be a suitable TAG as a digestive retardant among them. Each 10% replacement of edible oils by BOO gave 15% to 30% reduction of the lipolysis rate in vitro . Resistant TAGs that are able to melt or solubilize into liquid oil at body temperature have some potential as a digestive retardant for lipids.

PRACTICAL APPLICATIONS

Visceral fat accumulation and obesity in humans are thought to be correlated with the rate of lipid digestion and absorption. The entire rate of lipid absorption is controlled by their partial replacement with some digestive retardant. Resistant triacylglycerols may have some potential as a digestive retardant of lipids. Results of the present study propose a new fat system for foods with antiobesity effect.     

鳙鱼头汤中微/纳胶粒的体外消化特性及加工条件的影响

通过体外消化模型探究鳙鱼头汤中微/纳胶粒（micro/nano-sized colloidal particles,MNCPs）的消化特性及加工条件对其消化特性的影响。结果显示,加盐和均质未改变汤中MNCPs在消化过程中的整体变化趋势,鳙鱼头汤、加盐鳙鱼头汤和均质鳙鱼头汤中MNCPs在胃消化阶段,均表现为MNCPs膜上蛋白质被降解,脂滴释放并聚集。在小肠消化阶段,脂滴破散,MNCPs聚集体发生裂解;加盐后,MNCPs的平均粒径减小,但存在部分破乳现象并降低了总脂肪酸释放率;均质后,MNCPs的平均粒径进一步减小,MNCPs重新排布,改变了原有膜结构,增加了MNCPs中脂质和酶的接触位点,促进脂肪酸释放,在一定程度上弥补了加盐后鳙鱼头汤中部分脂肪酸释放率的降低。因此,盐和均质引起的MNCPs组成和微观结构的变化是导致MNCPs消化差异的主要原因。     

从农田到餐桌到营养:食物组分化学结构变化对健康效益的影响

食物富含多种化学组分,食物组分经历了加工释放与降解和体内吸收与代谢等一系列过程,最终被机体利用。随着食品化学和食品营养学科的深入发展,食物组分从农田到餐桌到人体过程中的关键变化、影响因素和调控方法得到了高度关注和广泛研究。梳理了从农田到餐桌过程中食物营养组分的体外加工和体内消化吸收阶段的变化及对人体的健康效益,介绍了食物加工、人体摄入过程中营养组分的变化(化学结构氧化降解),包括食物基质的破碎、组分的释放、体内的消化吸收,以及营养与功能组分发挥的健康功效等;分析了食物组分从农田到餐桌到人体过程中的关键影响因素,包括食物加工的方法和条件、食物的原始状态、食物的种类、食物基质性质和人体健康状态等;总结了食物从农田到餐桌到人体变化过程的营养功能强化策略,包括加工方法优化、膳食来源选择、食物形式选择、烹饪方法优化以及营养与功能组分递送系统的选择等;对未来食品营养产业的健康和可持续化发展进行了展望。