功能性成分对食物血糖应答影响的研究进展

近些年来,糖尿病已成为影响国民健康的重要慢性疾病。在防控糖尿病病情进展过程中,饮食管理尤为重要,亟需研发可降低血糖波动的低血糖生成指数(GI)产品。一些功能性成分,如膳食纤维、糖醇和植物提取物等可以用抑制消化酶活性,阻碍消化酶与碳水化合物的接触,减缓葡萄糖的吸收等方式实现降低食物血糖应答的目的。本文综述近年来有关功能性成分对血糖应答的影响研究,旨在为后续的低GI产品研发以及糖尿病人膳食指导提供一些的帮助。     

红小豆-粳米混合食物的碳水化合物体外消化速度研究

碳水化合物的消化速度直接影响着淀粉类主食的餐后血糖反应,因此可利用碳水化合物的体外模拟消化预测淀粉类主食品的血糖反应。用胰酶模拟小肠消化测定了几种烹调方法下红豆-粳米混合膳食中碳水化合物的消化速度,并探讨了其中快速消化淀粉(RDS)、慢速消化淀粉(SDS)和抗性淀粉(RS)相对含量的变化,结果表明:高压烹调显著提高了整豆-粳米混合食物的水解率和RDS含量,但豆粉-米混合食物在不同烹调压力下的差异不显著。整豆和大米分别烹调后再混合的食物与豆谷共同烹调食物相比,抗性淀粉的含量较高,且淀粉消化指数较低。红小豆-粳米混合食物的消化速度与精白粳米的消化速度呈显著性差异(p<0.05)。烹调方法对食物中碳水化合物的消化速度有很大影响。血糖调节异常的人群适合在主食原料中添加整豆类食物,以帮助稳定餐后血糖反应。     

食物成分对餐后血糖影响的研究进展

人体的餐后血糖反应（PGR）受到多种因素的影响,对于单一食物,其餐后血糖反应与食物成分、血糖指数（GI）和血糖负荷（GL）值之间显著相关;但对于混合膳食,食物成分与餐后血糖之间无显著相关性,而与GL和GI值之间存在一定的联系;另外,不同的烹调处理与饮食习惯,也会影响到餐后的血糖反应水平。通过选择低GI值的食物来控制食物的GL,以及调整烹调方法和饮食习惯,能够有效控制餐后的血糖反应水平。     

黔江肾豆碳水化合物组成及淀粉营养特性研究

以黔江肾豆为材料,对其碳水化合物组成和淀粉营养特性进行了研究。结果显示,肾豆富含碳水化合物(57.25±0.41)%,其中淀粉和粗纤维质量分数分别为(48.16±0.59)%和(3.59±0.11)%,表明肾豆是食物能量和膳食纤维的重要来源。淀粉直/支比0.63,较豌豆和部分绿豆高;肾豆淀粉消化特性分析显示慢消化淀粉(SDS)和抗性淀粉(RS)占比60.24%,可在混合膳食中起降低膳食整体碳水化合物消化速率的作用,对于慢性疾病如心血管等疾病和糖尿病的预防有益。体外血糖指数(GI)分析显示肾豆淀粉GI=88.5,为高GI;肾豆全粉GI=67.2,为中GI食品,肾豆全粉GI值低于肾豆淀粉,与其含蛋白质、纤维素、单宁、植酸和脂肪等成分有关。因此,食用全豆可减慢消化。黔江肾豆淀粉是制备粉丝、粉皮等深加工淀粉食品的良好淀粉来源。     

膳食脂质消化行径及其影响机制研究进展

膳食脂质是肌体能量、必需营养物质和生物活性成分的重要来源或载体,其在体内的消化行径往往受到消化场所及存在形态差异的影响。本文通过对膳食脂质在胃肠道内不同阶段的消化行径进行综述,分析膳食脂质在各阶段消化过程中的变化,阐明了膳食脂质在机体代谢过程中与脂肪酶、胆盐的亲和机制,以及小肠内的微生物菌群与膳食脂质在消化吸收中的相互作用,概述了不同类型、不同来源的膳食脂质间的消化差异。最后,本文总结了脂肪酸的链长及饱和程度、甘油三酯的结构、脂质的物理性质、乳化液滴的大小、界面性质及钙离子对膳食脂质体内消化的影响,以期为合理地摄入脂质、预防和治疗膳食脂质摄入过量引起的相关疾病提供依据,同时为研发功能结构脂及设计新型的含脂质食品提供参考。     

豆腐渣中膳食纤维测定方法之研究

豆腐渣中膳食纤维测定方法之研究辽宁商业高等专科学校（１２１０１３）佟德永马勇所谓膳食纤维，就是指“食物中具有生理活性的高分子化合物”，即通常所说的无效碳水化合物。近年来，随着人们生活水平的提高，食物中的不消化成分，已逐渐地从一些“贵族”的食谱中被划掉...     

从食物的碳水化合物谈糖尿病的膳食搭配

由于糖尿病患者的膳食受到诸多的限制,很多患者对每日膳食应该吃什么、喝什么感到茫然,从而影响了生活质量。与糖尿病患者病情直接有关的是膳食中的碳水化合物,为了评价食物中碳水化合物生理效应,营养学提出了两个重要指标——血糖生成指数(GI)和血糖生成负荷(GL)。本文从食物的血糖生成指数和血糖生成负荷两个方面,介绍了糖尿病患者的膳食搭配。     

枣干和米饭-枣混合餐餐后血糖反应

为研究烹调前后枣干及枣干配合粳米食用的餐后血糖反应,选择粳米饭、枣干、蒸枣、炖枣、枣＋米饭、枣米饭和枣米粥为研究对象,测定了11 名健康女性受试者食用上述所有样品餐后240 min的血糖反应和枣干烹调前后的质构指标,并计算血糖指数（glycemic index,GI）及血糖反应特征值。结果表明：几种烹调方式中,炖制对枣干的质构影响最大。枣干、蒸枣和炖枣的GI分别为56、65和56,其中炖枣的血糖曲线波动和血糖曲线下负面积最大。米饭、枣＋米饭、枣米饭、枣米粥的GI分别为78、75、82和85。需要控制血糖者可在替代高GI碳水化合物食物的前提下少量食用未烹调的枣干,但不宜食用烹调后的枣;烹调后食物混合餐的GI需实际测定,若根据公式将混合餐中各组分的GI按比例简单加和,会引起一定误差。     

内源性物质对不同品种大米淀粉消化性的影响

近年来培育出了低高血糖生成指数（GI）大米品种,但是其产生低GI作用机理并不明确,内源性非淀粉物质作为大米关键成分,对不同GI大米淀粉消化率的影响值得探讨。本研究以典型的两种不同GI大米作为研究对象,探究了去除内源性非淀粉物质对大米淀粉体外消化性、理化性质和微观结构的影响。结果表明,对于低GI品种,蛋白质和膳食纤维的去除显著促进了淀粉消化,使最终消化率提升了7.37%~13.28%,但高GI品种的内源性非淀粉物质对于淀粉消化性的影响并不显著。在理化性质上,蛋白质和膳食纤维的去除将淀粉的膨胀力显著提升至17.83±0.30g/g~13.44±0.27g/g,显著改变了米粉的糊化特性和热力学特性,从而使其更容易糊化和消化。在微观结构上,去除蛋白质和膳食纤维使淀粉颗粒结构减小了3~8 μm,蛋白质、膳食纤维和淀粉的相互作用提高了米粉的有序度和聚集结构。     

膳食纤维的定义、分析方法和摄入现状

本文主要论述膳食纤维的定义、分析方法以及人群摄入情况.中国营养学会将膳食纤维定义为不易被消化酶消化的多糖类食物成分(主要来自于植物的细胞壁),包含纤维素、半纤维素、树脂、果胶及木质素等.这种定义和FAO/WHO对膳食纤维狭义上的定义基本一致.而欧盟将其定义为具有3个或以上单体链节的碳水化合物聚合物,在人体小肠中不能被消化或吸收,包括天然存在于消费食物中的可食用的碳水化合物,由食物原料经物理、酶或化学法获得的碳水化合物,对健康表现出有益的生理作用的人造碳水化合物聚合物.根据现有定义,适用的主要分析方法有非酶重量法、酶重量法、酶化学法等.这些方法都是借鉴于AOAC方法.     

Slow digestion-oriented dietary strategy to sustain the secretion of GLP-1 for improved glucose homeostasis

Dysregulated glucose metabolism is associated with many chronic diseases such as obesity and type 2 diabetes mellitus (T2DM), and strategies to restore and maintain glucose homeostasis are essential to health. The incretin hormone of glucagon-like peptide-1 (GLP-1) is known to play a critical role in regulating glucose homeostasis and dietary nutrients are the primary stimuli to the release of intestinal GLP-1. However, the GLP-1 producing enteroendocrine L-cells are mainly distributed in the distal region of the gastrointestinal tract where there are almost no nutrients to stimulate the secretion of GLP-1 under normal situations. Thus, a dietary strategy to sustain the release of GLP-1 was proposed, and the slow digestion property and dipeptidyl peptidase IV (DPP-IV) inhibitory activity of food components, approaches to reduce the rate of food digestion, and mechanisms to sustain the release of GLP-1 were reviewed. A slow digestion-oriented dietary approach through encapsulation of nutrients, incorporation of viscous dietary fibers, and enzyme inhibitors of phytochemicals in a designed whole food matrix will be implemented to efficiently reduce the digestion rate of food nutrients, potentiate their distal deposition and a sustained secretion of GLP-1, which will be beneficial to improved glucose homeostasis and health.     

A comparative study on the structural and functional properties of water-soluble and alkali-soluble dietary fibres from rice bran after hot-water,ultrasound, hydrolysis by cellulase,and combined pre-treatments

The aim of the study was to estimate the optimum method to obtain water-soluble (WS-DF) and alkali-soluble (AS-DF) dietary fibres fibres from defatted rice bran (DRB) to develop functional components for food. The different pre-treatments of DRB, such as ultrasound (US) treatment, hydrolysis by cellulase (HC) and combined treatment (HC-US), were compared with hot-water (HWT) treatment on yields, and structural, physicochemical, and functional properties of WS-DF and AS-DF. Results showed that amounts of WS-DF (5.54–9.03 g/100 g) and AS-DF (7.22–9.58 g/100 g), and total dietary fibre (TDF) (42.21–45.44 g/100 g) obtained from the DRB after US, HC and HC-US treatments were significantly higher than that after HWT (6.36, 5.65 and 31.92 g/100 g, respectively). The FT-IR indicated that the effect of applied treatments on the changes of the chemical structure of polysaccharides was stronger for the WS-DF than that for the AS-DF. Scanning electron microscopy (SEM) showed that the surfaces of US-treated DFs particles were much more fractured than those after the HWT and HC. The combined HC-US treatment at 50°C for 30 min significantly enhanced the purity (85–91%) and homogeneity of RB DFs structure resulting in increased water-holding, swelling and glucose adsorption capacities compared to conventional processes maintaining acceptable bioactivity. Our study showed that conventional hot water extraction could be replaced with the ultrasonication technology as an effective tool for the modification of rice bran DFs’ structure and functional properties.     

可溶性膳食纤维对玉米淀粉体外消化的抑制作用

本文通过模拟人体胃肠道消化过程,研究四种可溶性膳食纤维(青稞β-葡聚糖(barley β-glucan,BBG)、黄原胶(xanthan gum,XG)、魔芋胶(konjac glucomannan,KGM)和罗望子胶(tamarind seed polysaccharide,TSP))对玉米淀粉消化的影响,并建立膳食纤维在胃肠道模拟体系下的表观黏度(60 s^-1)与预测血糖指数(predicted glycemic index,pGI)之间的关系,探究可溶性膳食纤维降低餐后血糖响应的机理。结果表明,添加0.1%的BBG、XG、KGM和TSP对淀粉水解的抑制率分别达到11.59%、35.90%、30.54%和19.62%,并能将淀粉的pGI值分别降低12.05、45.54、38.90和15.00。并且,随着可溶性膳食纤维在胃肠道体系下的表观黏度的增大,pGI值呈下降趋势,并且当XG、KGM和TSP的表观黏度超过4 mPa·s后,pGI值的下降趋势愈加平缓。因此,可溶性膳食纤维能够抑制玉米淀粉的消化,并且其黏度是降低餐后血糖响应的重要因素。此研究将为可溶性膳食纤维在降血糖功能方面的应用奠定理论基础。     

体外模拟胃、肠消化对6种黑色食品抗氧化成分及其活性的影响

通过体外模拟胃、肠消化法考察6 种黑色食品（黑米、黑苦荞、黑麦、黑豆、黑绿豆、黑小米）在胃、 肠道消化过程中抗氧化成分及其活性变化规律。结果发现,通过模拟胃消化2 h后,多酚和黄酮释放增长比例最高 的分别是黑小米和黑豆,分别增长28%和41%,进一步通过模拟肠消化2 h后,多酚和黄酮释放增长比例最高的分 别是黑麦和黑绿豆,分别增长113%和52%。1,1-二苯基-2-三硝基苯肼（1,1-diphenyl-2-picrylhydrazyl,DPPH）自 由基清除能力、亚铁还原能力（ferric ion reducing antioxidant power,FRAP）和2’-联氨-双-3-乙基苯并噻唑啉-6-磺 酸（2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid,ABTS）自由基清除能力在模拟胃消化阶段的增长比例 最高的分别是黑豆（114%）、黑绿豆（31%）和黑米（28%）,在模拟肠消化阶段增长比例最高的分别是黑苦 荞（161%）、黑小米（124%）和黑米（199%）。通过模拟胃蛋白酶、胰酶和胆汁等消化作用后能显著提升黑色 食品的黄酮、多酚释放量和抗氧化活性（P＜0.05）,尤其是黑米,在消化前后均表现出最强的抗氧化活性,通过 胃、肠消化后,其DPPH自由基清除能力、FRAP和ABTS＋·清除能力分别为4 531.79、3 729.69 μmol Trolox/100 g md和 3 727.14 μmol Trolox/100 g md,分别较未消化时增长了200%、171%和383%,是较有应用前景的一种黑色食品。     

Particle Size Distribution of Brown and White Rice during Gastric Digestion Measured by Image Analysis

The particle size distribution of foods during gastric digestion indicates the amount of physical breakdown that occurred due to the peristaltic movement of the stomach walls in addition to the breakdown that initially occurred during oral processing. The objective of this study was to present an image analysis technique that was rapid, simple, and could distinguish between food components (that is, rice kernel and bran layer in brown rice). The technique was used to quantify particle breakdown of brown and white rice during gastric digestion in growing pigs (used as a model for an adult human) over 480 min of digestion. The particle area distributions were fit to a Rosin–Rammler distribution function. Brown and white rice exhibited considerable breakdown as the number of particles per image decreased over time. The median particle area (x₅₀) increased during digestion, suggesting a gastric sieving phenomenon, where small particles were emptied and larger particles were retained for additional breakdown. Brown rice breakdown was further quantified by an examination of the bran layer fragments and rice grain pieces. The percentage of total particle area composed of bran layer fragments was greater in the distal stomach than the proximal stomach in the first 120 min of digestion. The results of this study showed that image analysis may be used to quantify particle breakdown of a soft food product during gastric digestion, discriminate between different food components, and help to clarify the role of food structure and processing in food breakdown during gastric digestion.     

抗氧化成分在消化过程中变化的研究进展

食物中的抗氧化成分具有促进健康和预防非传染性疾病的作用,近年来得到学术界和工业界的广泛关注,然而目前的研究主要还是停留在对于提取物的活性评价上,与实际的人体利用情况差异很大。食物消化过程中的p H值、各种消化酶类对食品抗氧化成分的稳定性存在潜在的影响。文章详述了近年来关于食品中多酚、黄酮、类胡萝卜素等主要的抗氧化成分在消化过程中结构变化的最新研究进展,并介绍了其抗氧化能力在消化前后的变化情况,以期为抗氧化成分的活性评价提供理论参考。     

植物蛋白及其酶水解产物对淀粉消化性的影响研究综述

谷物制品主要组分为淀粉,由于它容易在发酵过程中被降解而因消化吸收快,易引发人体餐后血糖水平上升,从而增加一些慢性疾病的发病率,如肥胖、糖尿病等。出于对人体饮食健康的重视度,调控米制品中淀粉消化性能而变得愈加重要。淀粉的消化率在很大程度上取决于食品加工中形成的食品成分和微观结构,确定食品成分之间的相互作用对于设计低消化率的淀粉食品也至关重要。本文主要是集中概述植物蛋白及其酶水解产物与淀粉间形成二元复合物体系并对其结构、功能性质的变化,进而对淀粉消化性的影响,目的为更好地获得有效调控淀粉消化性的方式,深入探讨淀粉复合物的消化性能的作用。明晰和掌控淀粉在特定加工过程中结构的转变及其与其他食品组分形成特定慢消化或抗消化结构域的机制是当前功能营养米制品开发亟待解决的问题之一,这一综述也是为淀粉食品的开发利用提供参考。     

Potential implications of oxidative modification on dietary protein nutritional value: A review

During food processing and storage, proteins are sensitive to oxidative modification, changing the structural characteristics and functional properties. Recently, the impact of dietary protein oxidation on body health has drawn increasing attention. However, few reviews summarized and highlighted the impact of oxidative modification on the nutritional value of dietary proteins and related mechanisms. Therefore, this review seeks to give an updated discussion of the effects of oxidative modification on the structural characteristics and nutritional value of dietary proteins, and elucidate the interaction with gut microbiota, intestinal tissues, and organs. Additionally, the specific mechanisms related to pathological conditions are also characterized. Dietary protein oxidation during food processing and storage change protein structure, which further influences the in vitro digestion properties of proteins. In vivo research demonstrates that oxidized dietary proteins threaten body health via complicated pathways and affect the intestinal microenvironment via gut microbiota, metabolites, and intestinal morphology. This review highlights the influence of oxidative modification on the nutritional value of dietary proteins based on organs and the intestinal tract, and illustrates the necessity of appropriate experimental design for comprehensively exploring the health consequences of oxidized dietary proteins.     

粮谷类低血糖生成指数食品研究进展

血糖生成指数（glycemic index,GI）低的食品可以帮助人控制食欲并延缓饥饿,利于控制体重,改善餐后葡萄糖和脂质水平,但是GI值受多种因素影响。因此,本文从营养成分、加工方式等角度综述了食品原料中的淀粉、蛋白质、脂质、功能因子之间的相互作用,以及不同加工方式导致食品GI值的变化,旨在通过对比讨论为开发低GI食品提供理论参考。同时对食品GI值的检测方法进行阐述,GI值的检测已不局限于人体实验测定,出现了更加便捷的体外消化实验测定,已被广泛应用于低GI食品的开发和检测。