酶法改性影响膳食纤维的构成及生物作用效果的研究进展

膳食纤维根据溶解性分为可溶性膳食纤维与不溶性膳食纤维.一些食品中可溶性膳食纤维的含量低限制了其在食品工业中的应用,因此将不溶性膳食纤维转变成可溶性膳食纤维的改性方法成为人们研究的目标.众多方法之中,在添加外源酶的作用下对不溶性膳食纤维进行酶法改性可以有效地增加膳食纤维溶解性.酶法改性后,膳食纤维的单糖组成、官能团、结构...     

Dietary fibre content of dry and processed beans

Common beans (Phaseolus vulgaris L.) are a good source of protein, vitamins, minerals and especially dietary fibre. As beans are never eaten raw, the effects of soaking, cooking, soaking–cooking and canning on soluble, insoluble and total dietary fibre contents of beans are studied. Total dietary fibre content was determined by enzyme-gravimetric method. The fraction of insoluble dietary fibre was corrected for the content of resistant starch, determined as part of the total starch in insoluble fibre. The results indicate that thermal processing decreased the insoluble fibre content, and consequently the total dietary fibre content of beans. Soaking and cooking of beans significantly (P⩽0.05) increased the resistant starch content. The data on dietary fibre content of processed food are much more relevant than those of raw food. Thus food composition tables should contain as much data on processed food as possible.     

不溶性膳食纤维的提取、表征及改性研究进展

合理摄入膳食纤维对机体健康至关重要。为了开发兼顾营养、感官与健康的膳食纤维强化食品,不溶性膳食纤维的分离提取与改性研究广受关注。大量研究运用物理作用力、化学反应或酶解等手段,对样品组成、结构以及性质进行改造,以强化其在食品加工与营养健康方面功能特性。改性产物作为添加成分对于食品的加工过程、产品品质及健康功效方面具有积极影响,有利于各类膳食纤维强化产品的开发。本文对近年来国内外文献报道的不溶性膳食纤维的提取、改性及应用相关研究成果进行梳理总结,以期为调控膳食纤维功能特性、开发高品质健康功能食品提供参考。     

麦麸不溶性膳食纤维提取方法及其对面制品品质影响的综述

麦麸不溶性膳食纤维具有良好的物化特性和生理功能特性，近些年来国内外学者对麦麸不溶性膳食纤维的关注度逐年提升。简述了麦麸膳食纤维和麦麸不溶性膳食纤维的组成和功能，介绍了麦麸不溶性膳食纤维的提取方法，如物理法、化学法、生物法和化学–酶法，及各种方法的优缺点；阐述了麦麸不溶性膳食纤维对面制品品质的影响，如对面条、馒头和面包品质的影响，旨在为深入研究麦麸不溶性膳食纤维的提取方法和在面制品中的应用提供参考。     

黑曲霉发酵法制备米糠粕可溶性膳食纤维工艺优化及其理化分析

可溶性膳食纤维（Soluble dietary fiber,SDF）分子量小、结构无序,有良好的理化特性。天然膳食纤维中可溶性膳食纤维含量少,生物利用率低,因此要对膳食纤维进行改性。传统改性方法如物理、化学法存在成本高、能耗高、污染环境的缺点。微生物产生的酶能断裂大分子糖苷键,将不溶性大分子转化为可溶性膳食纤维,因此发酵法是一种低成本、低能耗、绿色无污染的新型改性方法。本文系统阐述了发酵改性原理、影响改性效果的因素如接种量、温度、pH等,并进一步介绍了发酵改性膳食纤维的生理功能及其在面制品、肉制品、乳制品中的应用,为未来膳食纤维进一步开发与利用提供理论依据。

     

小麦膳食纤维对面粉流变学特性的影响

小麦膳食纤维分为不溶性膳食纤维和可溶性膳食纤维两类,在面制品中具有重要的应用价值。应用粉质拉伸仪研究了不溶性和可溶性小麦膳食纤维对面粉流变学特性的影响。结果表明,不溶性小麦膳食纤维对面团面筋具有恶化作用;可溶性小麦膳食纤维对面团面筋具有改良作用,可根据制作面食品的种类来决定添加小麦膳食纤维的种类和添加量。     

Composition,Nutrition, and Utilization of Okara (Soybean Residue)

Okara is a by-product generated during tofu or soymilk production processes. It contains about 50% dietary fiber, 25% protein, 10% lipid, and other nutrients. The huge quantities of okara produced annually pose a significant disposal problem. Extensive studies have been done on the chemical composition, nutritional values, and biological activities of okara and on its potential utilization. Due to its high fiber content and low production costs, okara is a good raw material and rich source for preparing fiber and could also be used as a dietary supplement to prevent diabetes, obesity, and hyperlipidemia. Chemical or enzymatic treatment, fermentation, extrusion, high pressure, and micronization can increase the content of soluble fiber of okara, which improves its nutritional quality and processing properties. Fresh okara putrefies quickly due to its high moisture content, so it should be dried as early as possible. This review focuses on the application of okara in the food industry as partial replacement for wheat or soy flour to increase fiber and protein contents of foods. Okara can also be used as a fermentation substrate to produce a variety of products (natto, fibrinolytic enzymes, α-glucosidase inhibitor, β-fructofuranosidase, edible fungi, iturin A, chitosan, alcohol, etc.) for human consumption and nonfood production. In addition, the application of okara in feed and environmentally friendly material has also been documented.     

柑橘皮渣膳食纤维的特性及其在食品中的应用

膳食纤维是人类的“第七种营养素”,具有预防肥胖,调节肠道菌群等生理活性。柑橘皮渣是膳食纤维的良好来源之一,目前国内对于柑橘皮渣膳食纤维的研究主要集中在制备工艺,但对柑橘皮渣膳食纤维在食品中的工业化应用研究还比较薄弱。因此,开发和利用柑橘皮渣膳食纤维已成为当前研究的热点。由于柑橘皮渣膳食纤维具有优异的理化性质,能够作为一种膳食补充剂应用于食品生产。因此本文主要对柑橘皮渣中膳食纤维的种类、含量、膳食纤维的性质及柑橘皮渣膳食纤维在食品中的应用进行了概述,以期为更好地开发和利用柑橘皮渣中的膳食纤维提供参考。     

不同溶解性膳食纤维的功能特性差异浅析 及其在肉制品中应用

膳食纤维是一种植物成分,在消化过程中胃中的酶不能将其分解,是人类所需的第七大营养素。膳食纤维按其溶解性可分为可溶性和不溶性膳食纤维两大类,而且不同溶解性膳食纤维功能特性方面有很大差异,一般可溶性膳食纤维形成溶胶或凝胶,有很强的吸附性和清除能力,一般研究水溶性膳食纤维的对胆酸、胆固醇及有害物质的吸附性能,以及清除自由基的能力。不溶性膳食纤维主要研究粒径、温度等因素,对膳食纤维的膨胀力、持水力、吸油力和结合水力的影响。可溶性与不溶性膳食纤维的制备工艺方法存在差异,得率因品种不同有较大差异,持水力、溶胀率等理化特性也差异很大。本文还介绍了国内外将多种不同类型和来源的膳食纤维添加在肉制品(香肠、火腿、重组肉制品、凝胶肉制品、汉堡等)中的应用研究进展。目前对于不同溶解性膳食纤维的性质还没有确切科学的结论。如果能将不同膳食纤维本身的性质研究透彻,确定什么理化特性或结构特征赋予了膳食纤维在不同功能食品中的各种功能特性,将使商业与研究如何选择和制备合适品种的膳食纤维提供科学依据。     

脱蛋白结合超微粉碎对豆渣膳食纤维成分及功能特性影响

研究脱蛋白方法结合超微粉碎处理豆渣对其化学组成和功能特性的影响,当豆渣样品进行酶或碱处理时,它的总膳食纤维(TDF),不溶性膳食纤维(IDF)的质量分数分别增加了18.6-32.9%,22.6-34.4%,并且它们的功能特性(持水力,膨胀力和持油力)显著(p < 0.05)增加,但可溶性膳食纤维(SDF)质量分数与处理前豆渣没有显着差异。经超微粉随后,随着豆渣膳食纤维粒径减小,豆渣膳食纤维中可溶性膳食纤维质量分数提高了170% 以上,持水力和膨胀力显着下降(p < 0.05),持油力先下降后上升。结果表明,应用碱性蛋白酶和超微粉碎进行前处理,得到的豆渣中TDF和SDF的含量最高,这可能是在食品中加工高质量膳食纤维的潜在方法。     

Chemical profile, functional and antioxidant properties of tomato peel fiber

Tomato processing residue is defined as a secondary raw material that can increase its value, being considered a potential source of dietary fiber and bioactive compounds. Commercial tomato peel fiber has been analyzed to ascertain the proximate and nutritional composition (moisture, fat, protein, dietary fiber, ash, and minerals), the fractions (insoluble, IDF, and soluble, and SDF) and sugar composition of dietary fiber, functional properties (water retention capacity, WRC, swelling capacity, SWC, fat absorption capacity, FAC, glucose diffusion retardation index, GDRI, and osmotic pressure), total antioxidant activity (AA), and the content of antioxidant bioactive compounds (phenolic compounds and lycopene). To extract phenolic compounds and dietary fiber, three methods were assayed in this study: enzyme hydrolysis, maceration, and ultrasonic assistance. The content of TDF was 84.16%, and the major fraction was the IDF (71.82%), formed mainly by hemicelluloses. Tomato peel fiber retained 6.76 g of water/g as WRC, and it was significantly correlated with the IDF content. In addition, the content of IDF determined the low FAC and SWC and the GDRI at 60 min (39.22%). The main phenolic compound was rutin, followed by naringenin, rutin derivatives, and chlorogenic acid derivatives. These were better extracted using ultrasonic assistance, whereas lycopene showed mean values between 3 and 4 mg/100 g. The AA of tomato peel fiber was low, since the phenolic compounds are mainly bound to the cell wall of plant, showing a low capacity for scavenging radicals. Due to its chemical profile and functional properties, tomato peel fiber can be used as a food supplement, improving the different physical, chemical, and nutritional properties of foods. However the color and flavor of this product must be considered in its applications to avoid a negative effect on the sensory characteristic of the foods to which it is added.     

挤压提高膳食纤维水溶性的研究进展

膳食纤维中水溶性膳食纤维的含量对其功能、口感和使用范围具有重要的影响。植物性食物残渣含有丰富的膳食纤维,但其主要成分为水不溶性膳食纤维,严重限制其良好资源的利用。大量研究表明,挤压加工能显著提高这类膳食纤维中水溶性膳食纤维的含量,改善膳食纤维的功能性质,在膳食纤维的开发利用方面具有广阔前景。本文在总结近年来不同富含膳食纤维原料挤压的工艺创新和最佳条件的基础上,探讨了挤压提高水溶性膳食纤维含量的影响因素及机理,旨在为今后高品质膳食纤维的开发与应用提供参考。      

Effects of fiber addition on antioxidant capacity and nutritional quality of wheat bread

Wholegrain and high fiber foods are recognized as nutritious and healthful products due to their content of dietary fiber, antioxidants and bioactive compounds. In this study, wheat, rye, barley, oat wholegrain flours and two fibers namely cellulose (insoluble fiber) and xanthan gum (soluble fiber) were used to replace a portion of wheat flour in pan bread to study effects of fibers on phenolic compounds, antioxidant capacity, dietary fiber fractions, and starch digestibility in vitro. Incorporation of wholegrain flours increased free and bound phenolics and antioxidant capacity of all the breads examined to various extent depending on the source of fiber. Additionally, soluble, insoluble and total dietary fiber fractions and total minerals increased with the addition of wholegrain flours or fibers. Rapidly and slowly digestible and resistant starches were not significantly influenced by adding wholegrain flours or fibers to breads. The study demonstrates the importance of enriching wheat bread with wholegrain flours to boost antioxidants and dietary fibers. On the other hand, more research is required to better understand impact of wholegrain flours or fiber on starch digestibility in vitro and glycemic response.     

Nutritional characterization of tomato fiber as a useful ingredient for food industry

Tomato by-product consists of peels and seeds, presenting peel high fiber content. In this work, “tomato fiber” (TF) samples, obtained from tomato peels (after tomato processing) by a patented process, were characterized in terms of fiber and macronutrients (proteins, ash, total available carbohydrates and soluble sugars). From our results, TF is mainly composed by carbohydrates, with an average value of 80% of total dietary fiber (much higher than other vegetable by-products), being insoluble fiber the major component. The results obtained in this study reveal the high interest of TF as a food ingredient to be used as a valuable ingredient of new functional foods, enhancing insoluble fiber intake in the population.Industrial RelevanceThe use of tomato by-product reduces costs and justifies new investments in equipment, providing a correct solution for the pollution problem connected with tomato processing. The results obtained in this study reveal the high interest of TF as a food ingredient to be used as a valuable ingredient of new functional foods, enhancing insoluble fiber intake in the population. According to the Regulation 1924/2006, the product TF characterized in this study can be considered under the denomination of “Source of Fiber” (more than 3 g/100 g), and for that reason food products containing the above mentioned fiber in quantities equal or superior to 3.9%, could also include the same declaration of nutritional properties in their labeling.     

复合菌系发酵改性对豆渣膳食纤维结构及物化特性的影响

为促进芸豆渣的综合利用,对豆渣进行发酵改性,以改善其基本结构并提高其物化特性。利用复合菌系进行发酵,响应面优化制备工艺,分离可溶性膳食纤维和不溶性膳食纤维,对发酵前后的膳食纤维进行表观结构及物化特性的分析。发酵可溶性膳食纤维含量为17.47%,提高了11.84%,发酵后膳食纤维含量提高了2.81%。发酵后不溶性膳食纤维的持水力、持油力及膨胀力分别提高了2倍、6倍、1.9倍,吸附性及离子交换能力皆显著优于未处理的不溶性膳食纤维,发酵后可溶性膳食纤维的抗氧化能力也显著提高。发酵后的不溶性膳食纤维的微观结构褶皱更明显,发酵后的可溶性膳食纤维的颗粒明显增多变小且结构呈紧簇蜂窝状,红外光谱图也表明豆渣膳食纤维具有膳食纤维特有组分。发酵后的豆渣膳食纤维微观结构及物化特性皆有较明显地改善,其具备作为优质膳食纤维地潜能。     

Antioxidants Bound to an Insoluble Food Matrix: Their Analysis,Regeneration Behavior,and Physiological Importance

Dietary antioxidants play an important role in human health by counteracting oxidative stress and preventing chronic diseases. Most common dietary antioxidants in foods are vitamins, carotenoids, phenolic compounds, sulfur‐containing compounds, and neoformed antioxidants. Antioxidants may be present in free soluble or bound insoluble forms in foods. Antioxidants bound to insoluble food matrices have gained the spotlight because they exert their antioxidant effects much longer than free soluble ones. A direct procedure called QUENCHER has been shown to accurately measure the antioxidant capacity of antioxidants bound to insoluble matrices. This procedure overcomes the drawbacks of extraction‐dependent classical assays leading to underestimation of the total antioxidant capacity (TAC) of foods. This review focuses on antioxidants that are found naturally in foods or are formed in foods during processing specifically the antioxidants bound to the insoluble food matrices. The literature gap on the importance of bound antioxidants, their physiological relevance, and methods for measurement of their antioxidant capacity will be filled by this comprehensive review. In particular, chemical properties and health effects of food antioxidants, measurement of the TAC of foods by the QUENCHER method, digestion behavior of bound insoluble antioxidants, and their interactions with free soluble antioxidants are discussed throughout this review.     

Towards an updated methodology for measurement of dietary fiber,including associated polyphenols,in food and beverages

The analytical dietary fiber (DF) methods most widely used today were developed to determine non-starch polysaccharides and lignin. Updated dietary fiber definition includes all indigestible plant food constituents. Recent methods have proposed the measurement of resistant starch and oligosaccharides, but other major indigestible constituents such as polyphenolic compounds and resistant protein are still omitted in dietary fiber analysis. There is scientific evidence that an appreciable amount of dietary polyphenols are associated with the dietary fiber matrix, being a fermentable substrate for bacterial microflora. The objective of this work was to show polyphenols compounds are major constituents of dietary fiber and to propose a procedure for their measurement. Results showed that polyphenols are major constituents of DF, accounting from 1.4% to 50.7% (dry weight) of insoluble dietary fiber in plant foods and from 2.9% to 62.8% of soluble dietary fiber in common beverages.     

芋头在加工食品中的应用

<正> 芋头是天南星科中最重要的可食品种,具有悠久的栽培历史。2,000多年来,亚洲、非洲和波利尼西亚等地区的人,一直把它当作一种农作物。芋头遍布于热带地区,现在栽培的品种可能有数千种,大致可归纳为一个种属两个亚种,即生长1个中央大块茎的“dasheen”型和生长成很多小球茎的“eddoe”型。 芋头是一种淀粉质块茎,叶子简单宽阔而叶柄长。尽管很多芋头品种的外表、风味和质地均不一致,但其某些特征仍是相似的,如外表多毛、肉色变化     

黑小麦不溶性膳食纤维酶解产物组成分析及其对全谷物挤压膨化产品品质的影响

目的:对以黑小麦不溶性膳食纤维为原料所制备的木聚糖酶酶解产物(BWXH)的组成及应用特性进行系统分析,并研究其对全谷物挤压膨化产品品质的影响。方法:通过木聚糖酶对黑小麦不溶性膳食纤维进行酶解,得到BWXH,采用双波长法对BWXH中阿魏酰低聚糖含量(FOs)进行测定,并结合离子色谱、傅里叶变换红外光谱等技术对BWXH的单糖组成、低聚糖组成和红外光谱特征等理化特性指标进行了分析;模拟高温高压,对BWXH的稳定性进行检测;并将BWXH添加到全谷物挤压膨化产品中,其对挤压膨化产品的膨化率、感官评分及产品冲泡特性的影响进行分析。结果:BWXH中的FOs含量为0.104 mmol/g,阿魏酰基团含量为0.717 mg/g。通过离子色谱分析,FOs以DP2、DP3和DP4为主,主要单糖组成为阿拉伯糖、木糖和葡萄糖,其摩尔比为1.70:4.25:1.00,分支度(A/X)为0.40。高温高压(121 ℃,0.15 MPa)处理下能够进一步促进BWXH中高聚合度膳食纤维向低聚合度FOs的转变,使FOs含量增加。挤压膨化实验表明,适量(7%)添加BWXH可对谷物挤压膨化产品品质提升具有较好的改善作用。结论:BWXH作为一种低聚糖,可以应用于全谷物挤压膨化产品中,为黑小麦不溶性膳食纤维功能性食品配料的开发提供了一定理论依据。     

Study of the physicochemical and pasting properties of instant corn flour added with calcium and fibers from nopal powder

This work presents a physicochemical and apparent viscosity characterization of commercial nixtamalized corn flours (CNCF) added with nopal powder. The chemical proximate analysis of CNCF and traditional nixtamalized corn flours (TNCF) shows equal amounts of protein and fat, but the calcium content and total dietary fiber is higher in the TNCF. Nopal powder contains a high amount of Ca, soluble and insoluble fiber. The inclusion of 4% of nopal powder increases the calcium and fiber content of the CNCF to the level of traditional nixtamalized products steeped at 7 h. A pasting characteristics analysis based on the profile curves was done in order to study the influence of soluble and insoluble fibers on the pasting conditions of the studied samples added with nopal. At low temperatures the insoluble fiber governs the water absorption and below the gelatinization temperature (T_g) a competition between starch swelling and water absorption was found; for T higher than T_g the system is complex because it includes the interactions between soluble–insoluble fibers and exuding amylose.