脱脂椰蓉可溶性膳食纤维制备工艺及单糖组成和理化特性分析

以脱脂椰蓉为原料,采用响应面分析法建立酶-化学法提取可溶性膳食纤维得率的二次多项数学模型,并验证数学模型的有效性。探讨酶添加量、酶解时间、碱添加量、碱解时间因素对可溶性膳食纤维得率的影响,优化提取工艺参数,确定最佳提取工艺参数为混合酶添加量0.5%、酶解时间50?min、碱液（NaOH溶液）质量分数5%、碱解时间40?min,在此条件下椰蓉粕可溶性膳食纤维得率达11.78%,持水性、持油性和膨胀性分别为3.8?g/g、5.2?g/g和3.1?mL/g。红外光谱分析发现,脱脂椰蓉可溶性膳食纤维处于缔合状态的氢键较多;高效液相色谱结果表明,可溶性膳食纤维含有9?种单糖,其中甘露糖、氨基半乳糖、半乳糖、阿拉伯糖含量较高,分别为537.21、40.38、39.48?mg/L和15.83?mg/L。     

Cooking and texture properties of gluten‐free fettuccine processed from defatted flaxseed flour and rice flour

Nonconventional raw materials have been applied in gluten‐free pasta, to meet the demand of people with coeliac disease. The objective of this study was to evaluate the cooking properties and texture of pasta formulated with rice flour, defatted flaxseed flour and pregelatinised mixed flour of rice and flaxseed (80:20). For this experiment, simplex design was used. Cooking properties and texture were found within the quality limits established for this type of product. The pasta with the most desirable properties (short optimum cooking time (OCT), less solid loss (SL) and intermediate mass increase (MI)) was that one formulated with 43 g 100 g^?1 of pregelatinised flour, 47 g 100 g^?1 of rice flour and 10 g 100 g^?1 of defatted flaxseed flour. This formulation can be characterised as a food rich in dietary fibre and of high nutritional value.     

Response surface methodology for optimisation of soluble dietary fibre extraction from sweet potato residue modified by steam explosion

To make better use of sweet potato residue (SPR), a new pretreatment method, steam explosion (SE), can increase its content of soluble dietary fibre (SDF). Response surface methodology (RSM) was used to determine the SE variables for optimum SDF yield. The optimal conditions were a steam pressure of 0.35 MPa, a residence time of 121 s and a sieving mesh size 60. Under the optimised conditions, the content of SDF from SPR reached 22.59 ± 0.35%, an increase of 18.78% compared with that (3.81 ± 0.62%) from untreated SPR. The water‐holding capacity, oil‐holding capacity (OHC) and swelling capacity of SDF were improved by SE. Scanning electron micrograph (SEM) images demonstrated that SDF had become poriferous, loose and dilatants after SE treatment. This technology provides an efficient process for increasing the industrial production of SDF from SPR.     

Green extraction of soluble dietary fibre from coffee silverskin: impact of ultrasound/microwave-assisted extraction

Coffee silverskin (CSS), a potential source of soluble dietary fibre (8%–11%), is a major coffee by-product obtained during the coffee roasting process. Ultrasound-assisted extraction (UAE) and microwave-assisted extraction (MAE) have been considered as efficient and economic novel extraction techniques. In this study, UAE, MAE and simultaneous ultrasound–microwave-assisted extraction (UMAE) techniques were investigated for soluble dietary fibre (SDF) extraction from CSS and compared with conventional solvent extraction (CSE). The highest recovery rate of SDF was accomplished by UMAE (42.7 ± 0.4%), which was 1.5-fold, 1.9-fold and 1.2-fold of the recovery rates achieved by CSE, UAE and MAE, respectively. The extraction time of UMAE was 20 min, which was the same as UAE and MAE, and 4.5-fold less than CSE. It implied that the combination of UAE and MAE could enhance the extraction process by increasing the recovery rate as well as by reducing extraction time as compared with CSE or other individual novel extraction methods applied. Nutritional composition and physicochemical characteristics of the SDF extracts from CSS were also investigated in the study.     

Chemical and functional properties of the native banana (Musaacuminata × balbisiana Colla cv. Awak) pseudo-stem and pseudo-stem tender core flours

This research was conducted to evaluate the differences in chemical composition and functional profiles of native banana pseudo-stem flour (NBPF) and boiled tender core of the banana pseudo-stem flour (TCBPF). Chemical analyses indicated that the proximate contents (moisture, fat, protein and ash), were significantly higher in TCBPF than in NBPF. The levels of total dietary fibre, insoluble dietary fibre, lignin, hemicellulose and cellulose were all higher in NBPF than TCBPF, while there was no significant difference in soluble dietary fibre. NBPF also had higher contents of polyphenols and flavonoids than TCBPF. Both the antioxidant capacity and the free radical-scavenging capacity were higher in NBPF than in TCBPF. On the other hand, the TCBPF showed significantly higher swelling power, water holding capacity and solubility, although its oil holding capacity was lower than NBPF. We conclude that banana pseudo-stem flour is a potential functional food ingredient for products containing high dietary fibre.     

Organoleptic and nutritional evaluation of wheat breads supplemented with soybean and barley flour

Supplementations of soy (full fat and defatted) and barley flours to wheat flours at 5, 10, 15 and 20% levels were carried out to test the effects on organoleptic and nutritional evaluation of the supplemented bread. Additions of 15% barley flour, 10% soy flour (full fat and defatted), 15% barley plus full fat soy flour and 15% barley plus defatted soy flour to wheat flour produced acceptable breads. However, substitution of soy (full fat and defatted) and barley flours to wheat flour separately and in combinations at 20% levels did not produce organoleptically acceptable bread. Various nutritional parameters, such as protein, fat, total lysine, protein digestibility (in vitro), sugars, starch digestibility (in vitro), total and available minerals, antinutrients, dietary fibre and β-glucan were determined in supplemented and control bread. Increasing the level of substitution from 5 to 10% of full fat and defatted soy flour to wheat flour significantly (P<0.05) increased protein (from 12.1 to 13.7 and 12.4 to 13.8%), lysine (from 2.74 to 3.02 and 2.76–3.05 mg/100 g protein) and total calcium (from 70.2 to 81.4 and 71.9–81.8 mg/100 g) contents. However, there was also an increase in phytic acid (238–260 and 233–253 mg/100 g), polyphenol (324–331 and 321–329 mg/100 g) and trypsin inhibitor activity (193–204 and 193–198 TIU/g). When barley flour was substituted separately, and in combinations, with full fat and defatted soy flour up to 15%, this significantly increased the contents of protein, total lysine, dietary fibre and β-glucan. It may be concluded that breads supplemented with barley and defatted soy flour, up to a 15% level, are organoleptically and nutritionally acceptable.     

高粱乌米可溶性膳食纤维提取工艺优化及功能性分析

本文采用碱法从高粱乌米中提取可溶性膳食纤维（soluble dietary fiber,SDF）,在单因素实验的基础上,使用响应面法优化提取SDF并对其理化性质及抗氧化活性进行研究。优化后的最佳提取条件为料液比1:21.40 g/mL,碱液浓度2.11%,碱解时间90.71 min,提取温度59.30 ℃,SDF最大得率为20.21%。同时,SDF的持水能力、持油能力和溶胀能力分别为3.48±0.05 g/g、1.50±0.07 g/g和13.22±0.03 mL/g。此外,实验结果还表明SDF具有较高的抗氧化活性,对自由基的清除率与SDF浓度呈正相关。在SDF浓度为3.5 mg/mL时,对羟基自由基（·OH）、DPPH自由基和超氧阴离子（O₂-·）的清除率分别为62.02%、56.98%和61.03%。结果表明高粱乌米是一种潜在的天然膳食纤维来源和潜在的功能性食品成分。     

High hydrostatic pressure improves the functionality of dietary fibre in okara by-product from soybean

The combined effect of high hydrostatic pressure (HHP) and controlled temperature on total (TDF), soluble dietary fibre (SDF) content, and its associated hydration properties were assayed in okara, a rich-in-insoluble dietary fibre residue from the soydrink- and tofu-making process of soybean. TDF in starting unprocessed okara was 45.7% and its SDF to TDF ratio was 4.6. When dry, hydrated and autoclaved okara samples, were subjected to HHP-treatment (200 and 400 MPa) at 30 and 60 °C, the amount of SDF went up by more than 8-fold. At 200 MPa, TDF was not significantly different from control, but at 400 MPa values varied from 38.1 to 64.8%. In vitro physicochemical properties of okara were also modified by HHP-treatment. Therefore, the effect of a combined treatment with hydration, temperature and HHP-technology on the improvement of the soluble fibre fraction (%) and functionality of certain vegetable by-products from the food industry could be very useful for the elaboration of food ingredients with potential health-promoting effects.Industrial relevanceThis article deals with the effect of HHP-treatment on dietary fibre fractions and associated physicochemical properties in okara by-product from soybean. Results suggested that the higher the hydrostatic pressure and temperature applied, the higher the ratio of soluble to total dietary fibre in okara. Likewise, the effect of combined hydration, mild temperature, and HHP-treatment could increase the soluble fraction (%) of other rich-in-insoluble dietary fibre vegetable by-products, which could potentially be used as valuable ingredients of new functional foods.     

Effect of partially defatted coconut flour on the rheological,physico-sensory characteristics and fatty acid profile of no-added fat rusk

Partially defatted coconut flour (PDCF) as a source of medium chain fatty acids was selected to replace fat in rusk formulation. Effect of replacement of wheat flour with PDCF (10%, 20% and 30%) on quality characteristics of rusk was studied. Increasing PDCF from 0% to 30% decreased farinograph water absorption, amylograph peak viscosity and overall quality score (52.5 to 19.5) of rusk. Use of additive mix, AM (4% dry gluten powder + 0.002% fungal α-amylase) to 20% PDCF, increased the farinograph dough stability, strength of the paste during heating and overall quality score (39.5 to 50.5). The rusk with 20% PDCF + AM was stable up to 30 days, had 1.6, 5.5 times higher protein and dietary fibre contents as compared to control rusk respectively. The fat in the rusk had zero trans fatty acids and contained 66.2% medium chain fatty acids with lauric acid as a major fatty acid.     

Treatment with hydrogen peroxide improves the physicochemical properties of dietary fibres from Chinese yam peel

Yam is a common ‘medicine food homology’ vegetable in Asia, and its peel is often considered a food residue during processing or cooking. In this work, the effects of hydrogen peroxide modification on the dietary fibres (DFs) from Chinese yam peel (CYP) were investigated. The structural characteristics of soluble dietary fibre (SDF), insoluble dietary fibre (IDF), modified soluble dietary fibre (MSDF) and modified insoluble dietary fibre (MIDF) were analysed using Fourier-transform infrared spectroscopy, X-ray diffraction, differential scanning calorimetry, granularity analysis, scanning electron microscopy and GC-MS (monosaccharide composition). As results, after modification with hydrogen peroxide, the sizes of the DFs were reduced and MIDF exposed more cellulose. Experiments on the physicochemical and functional properties of DFs showed that MSDF and MIDF obtained a better water holding capacity, oil absorption capacity, swelling capacity and absorption abilities with altered structures, which is of great importance in food processing and development.     

Modification of physiochemical properties of copra meal by dilute acid hydrolysis

Coconut residue or copra meal (CM), a by‐product after pressing cream and oil out of the coconut meat, is a good source of dietary fibre (DF), but high water‐holding capacity (WHC) of CM limits the quantity of fibre incorporated into food products. This study focused on the modification of CM physiochemical properties using acid hydrolysis to improve its potential utilisation as source of food fibres or low‐calories bulk ingredients in food applications. Acid hydrolysis using 0.5% HCl significantly reduced swelling capacity (SC) and water retention capacity, whereas bulk density (BD) and soluble DF content of the modified CM significantly increased. Monosaccharide composition profile, gel penetration profile and FT‐IR spectra indicated the destruction of CM matrix structure. This destruction increased compactness of the structure and lessened the ability of CM to hold water. Substituting the modified CM for wheat flour in bread and cookies significantly improved bread and cookies qualities compared with the use of the untreated CM. Response surface methodology showed that HCl concentration, hydrolysis temperature and time influenced properties of the modified CM. The models predicting their relationships were also generated.     

亚临界丁烷制备豆粕及其蛋白氧化稳定性研究

采用亚临界丁烷对大豆粉脱油制得豆粕(DSF-B),并与正己烷制备豆粕(DSF-H)比较,对分离蛋白得率及热变性、豆粕残余极性脂和在贮藏过程中蛋白的氧化进行分析。DSF-B的蛋白得率(32.1%)比DSF-H高(约6%),蛋白热变性二者一致,且11S变性温度低于工业白豆片。残余极性脂分析,DSF-B比DSF-H总量低、磷脂含量高,脂肪酸组成有差异。模拟贮藏试验表明,DSF-B在贮藏中蛋白更易被氧化,这可能与极性脂的组成有关。亚临界萃取技术无高温处理、可选溶剂多样,可开发应用于大豆等植物蛋白制品。     

复合酶法提取黄秋葵可溶性膳食纤维的工艺优化及其理化特性、结构表征

以黄秋葵果荚为原料,采用复合酶法提取可溶性膳食纤维(soluble dietary fiber,SDF),通过单因素实验,探究不同因素对黄秋葵SDF得率的影响。在单因素实验的基础上进行响应面分析,得到复合酶法制备黄秋葵SDF的最优条件;并测定所得黄秋葵SDF的理化特性,并对其进行结构表征。结果表明:在料液比1:24 g/mL、复合酶添加量1.8%、酶解时间54 min、酶解温度62℃的提取条件下,黄秋葵SDF得率达到最大值,为10.94%,与预测值之间的相对误差为1.48%。黄秋葵SDF的持水力、膨胀力和持油力分别为5.61 g/g、3.35 mL/g和4.88 g/g,良好的理化特性使其具有成为通便保健食品原料的潜力。黄秋葵SDF的微观结构显示,经过酶的作用,黄秋葵SDF表面的淀粉类物质被充分除去;黄秋葵SDF的晶体结构符合纤维素I晶型的特征,其红外光谱图线符合膳食纤维类物质的典型特征。     

Nutritional and functional properties of Vicia faba protein isolates and related fractions

The goal of this research was the characterisation of Vicia faba (broadbean) protein isolates and related fractions in order to determine whether this grain legume could be used for production of high quality protein products and other fractions rich in functional components. Alkaline extraction of the defatted seed flour, followed by precipitation at the isoelectric pH, yielded a 92% protein isolate with a high oil absorption capacity. The contents of the favism-inducing glycosides, vicine and convicine, in the isolate were reduced by more than 99% as compared to the original flour, although the amino acid composition was similar to that of the flour. Some of the by-products of protein isolate production may also be of interest from a nutritional and functional point of view. Thus, the oil resulting from hexane extraction of the flour is rich in unsaturated fatty acids, and polyphenols (resulting from extraction of the defatted flour with acetone) showed a high ABTS radical-scavenging activity. In addition, the solid residue (resulting from protein solubilisation) was high in fibre and showed good water absorption. These results show good nutritional and functional properties in V. faba protein isolates and related fractions, which may favour the revalorisation of this traditional bean crop.     

脱脂椰蓉粉亚临界水降解动力学及产物形态研究

以脱脂椰蓉为研究对象,考察了不同亚临界水降解条件对其降解过程的影响,并测定了100~200 ℃,不同反应时间下降解产物中还原糖的含量。采用Saeman模型对实验数据进行模拟,建立脱脂椰蓉粉亚临界水降解反应动力学方程,得到亚临界水降解动力学参数;并对降解物进行形态学分析。结果表明,Seaman模型能较好的反映脱脂椰蓉粉亚临界水降解的过程,初步降解的反应活化能E_a1为35.94 kJ/mol,还原糖降解活化能E_a2为32.12 kJ/mol,指前因子K₁₀为6.50×102 min-1、K₂₀为3.24×102 min-1。该降解过程在140 ℃、30 min能得到温度的高还原糖产物。脱脂椰蓉粉在亚临界水中降解过程中,形态随温度、时间变化而变化,随着温度的升高原料的转化率逐渐升高,原料由固态转化为液态部分越多,水解程度越大。扫描电镜结果表明,随着降解温度的升高和降解时间的延长,脱脂椰蓉粉的纤维结构破坏越显著。     

不同工艺制备刺梨果渣膳食纤维及品质分析

以可溶性膳食纤维（SDF）得率为评价指标,确定化学法、酶法和发酵法制备刺梨果渣膳食纤维最佳制备工艺,对3种方法膳食纤维样品及原果渣进行品质分析。结果显示,绿色木霉发酵法为最佳处理方法,优化条件下可溶性膳食纤维得率为12.75%,比原果渣可溶性膳食纤维提高了74.42%。3种处理方法得到的总膳食纤维（TDF）膨胀力、持水力、持油力、胆固醇吸附力均比原果渣有所提高。电镜扫描发现3种处理方法均使纤维结构发生不同变化。红外光谱扫描分析显示,刺梨可溶性膳食纤维含有糖的特殊吸收峰,处理条件不同导致官能团组成不同,酶法和发酵法可溶性膳食纤维含有半乳糖,化学法可溶性膳食纤维没有。     

Dietary fiber from coconut flour: A functional food

To determine the effectiveness of dietary fiber present in coconut flour as a functional food, the following studies were conducted: (a) Dietary Fiber Composition and Fermentability of Coconut Flour; (b) The Effect of Coconut Flour on Mineral Availability from Coconut Flour Supplemented Foods; (c) Glycemic Index of Coconut Flour Supplemented Foods in Normal and Diabetic Subjects; and (d) The Cholesterol Lowering Effect of Coconut Flakes in Moderately Raised Cholesterol Levels of Humans. The dietary fiber content of coconut flour was 60.0 ± 1.0 g/100 g sample, 56% insoluble and 4% soluble. Fermentation of coconut flour produced short chain fatty acids with butyrate (1.73 ± 0.07 mmol/g fiber isolate) > acetate (1.40 ± 0.12; (P < 0.05) > propionate (0.47 ± 0.01; P < 0.05). Iron and zinc availability were highest for carrot cake (Fe, 33.3 ± 0.7%; Zn, 12.6 ± 0.1%) supplemented with 20% coconut flour while multigrain loaf supplemented with 10% and macaroons with 25% coconut flour were highest for calcium availability (63.4 ± 8.0% and 38.7 ± 1.1%, respectively). Increasing concentrations of dietary fiber from coconut flour did not affect mineral availability from all test foods. The significantly low glycemic index foods (< 60 mmol × min/l) investigated were: macaroons (45.7 ± 3.0), carrot cake (51.8 ± 3.3) and brownies (60.1 ± 5.4) with 20–25% coconut flour. The test foods containing 15% coconut flour has a glycemic index ranging from 61 to 77 mmol × min/l. Among the test foods, pan de sal (87.2 ± 5.5) and multigrain loaf (85.2 ± 6.8) gave significantly higher glycemic index with 5% and 10% coconut flour. On the other hand, granola bar and cinnamon which contained 5% and 10% coconut flour, respectively gave a glycemic index ranging from 62 to 76 mmol × min/l and did not differ significantly from the test foods containing 15% coconut flour (P < 0.05). A very strong negative correlation (r = − 85, n = 11, P < 0.005) was observed between the glycemic index and dietary fiber content of the test foods supplemented with coconut. There was a significant reduction (%) in serum total and LDL cholesterol for: oat bran flakes, 8.4 ± 1.4 and 8.8 ± 6.7, respectively; 15% coconut flakes, 6.9 ± 1.1 and 11.0 ± 4.0, respectively; and 25% coconut flakes, 10.8 ± 1.3 and 9.2 ± 5.4, respectively (P < 0.05). Serum triglycerides were significantly reduced for all test foods: corn flakes, 14.5 ± 6.3%; oat bran flakes, 22.7 ± 2.9%; 15% coconut flakes, 19.3 ± 5.7%; and 25% coconut flakes, 21.8 ± 6.0% (P < 0.05). Results from the above study can be a basis in the development of coconut flour as a functional food.

Industrial relevance

The functionality of coconut flour in terms of prevention for risk of chronic diseases, e.g. diabetes mellitus, cardiovascular diseases (CVD) and colon cancer, revealed increase production of coconut and coconut flour. The production of coconut flour is very economical because it can be produced in a small or large scale. The raw material is obtained from the by-product (waste) of the coconut milk industry and the process and equipment used in its production is simple and cheap. Coconut flour as a good source of dietary fiber can be added to bakery products, recipes and other food products for good health.     

响应面法优化金针菇中水溶性膳食纤维的提取工艺

该研究采用超声波辅助碱法提取金针菇可溶性膳食纤维（SDF）,利用响应面法对金针菇SDF的提取工艺进行优化。选取液料比、超声时间、超声温度、碱液质量分数为影响因素,以金针菇SDF提取率为响应值,应用Box-Behnken试验设计建立数学模型,进行响应面分析,并对其理化性质进行检测。结果表明,超声波辅助碱法提取金针菇SDF的优化工艺条件为超声功率150 W,液料比10∶1（mL∶g）、超声时间69 min,超声温度49 ℃,碱液质量分数5.10%。在此条件下金针菇SDF提取率可达20.25%,持水力为5.18 g/g,膨胀性为4.64 mL/g,持油力为4.77 g/g。     

琯溪蜜柚柚皮膳食纤维提取及其理化特性

以福建省平和县琯溪蜜柚为材料,以NaOH溶液浓度、提取温度和加热时间设计三因素三水平正交实验,以总膳食纤维(TDF)提取率、不溶性膳食纤维(IDF)与水溶性膳食纤维(SDF)的比值接近3∶1为目标,优化柚皮膳食纤维提取工艺。结果表明:柚皮膳食纤维(DF)最佳提取工艺为碱液浓度8%,提取温度75℃,加热时间90 min,其提取率为75.12%,IDF/SDF比值为2.12。柚皮TDF粒径主要分布在<120目的范围,占总比重的30.13%,其次是位于120～140目的DF膳食纤维,占总比重的21.84%;SDF具有良好的膨胀力,达到17.642 0 g/g,IDF持水力较好,为5.711 5 g/g;柚皮DF对亚硝酸盐(NO2-)吸附能力强,且DF对NO2-的吸附量随着时间的延长而增加,至240 min时吸附量最高,达到18.01 g/g(pH 2)和15.92 g/g(pH 7),相同时间内,在pH 2的模拟环境下,DF对NO2-吸附能力优于pH 7的;柚皮DF对脂肪酸的吸附效果良好,且相同时间内DF对不饱和脂肪酸的吸附量(1.026 0 g/g)高于对饱和脂肪酸的(1.124 0 g/g),说明DF吸附动物性油脂效果更好。     

The advantage of using extrusion processing for increasing dietary fibre level in gluten-free products

Gluten-free products generally are not enriched/fortified and frequently are made from refined flour and/or starch. Such products have been found to provide lower amounts of total dietary fibre than their enriched/fortified gluten-containing counterparts.The objective of this study was to increase the level of total dietary fibre in gluten-free products by using extrusion technology and by incorporating a number of different fruits and vegetables, such as apple, beetroot, carrot, cranberry and gluten-free Teff flour cereal. The materials were added at the level of 30% into the gluten-free balanced formulation (control) made from rice flour, potato starch, corn starch, milk powder and soya flour. Different process conditions, such as water feed rate 12%, solid feed rate 15–25 kg/h, screw speed 200–350 rpm, barrel temperatures: 80 °C at feed entry and 80–150 °C at die exit were used. Pressure, material temperature and torque were monitored during extrusion runs. The relationships and interactions between raw ingredients, extrusion processing parameters and resulting extrudate nutritional and textural properties were investigated.The results of this study clearly show that extrusion technology has the potential to increase the levels of total dietary fibre in gluten-free products made from vegetables, fruits and gluten-free cereals.