藜蒿膳食纤维的制备、组成及性能研究

本文以江西鄱阳湖地区盛产的藜高为原料，采用AACC改良法分别测试了其ADF，NDF，IDF，SDF和TDF的含量，并用酶法分别制备了其IDF和SDF，测试了IDF的溶胀性，持水性，SDF的粘均分子量，组成单糖的种类以及两者的残留蛋白，糖醛酸含量等理化指标，讨论了其组成与性能之间的关系，进一步的工作正在进行之中。     

Non‐digestible carbohydrates in Brazilian soybean seeds [Glycine max (L.) Merril]

Non‐digestible carbohydrate fraction (NDCF) consists of a range of bioactive compounds that escape digestion in the small intestine. NDCF is mainly composed of dietary fibre (DF) and non‐digestible oligosaccharides (NDO). The objective of this work was to analyse directly and compare the NDCF in two Brazilian cultivars of soybean seed with commercial flour. Brazil is the second major soybean producer in the world. The seed cultivars showed on average a NDCF value of 32.80 g per 100 g dry weight (dw). Regarding DF, insoluble DF (IDF) was the main fraction amounting on average to 98%. Uronic acids were significantly higher than neutral sugar (NS) in IDF and soluble DF (SDF) fractions. There was a considerable amount of Klason lignin – on average 84.14% of DF. Regarding NS profile, mannose was the most important sugar in SDF, whereas galactose and arabinose were predominant in IDF. Stachyose was the main oligosaccharide in NDO. DF and NDO were in the same proportion (94.2:5.8) in tested cultivars. No differences in swelling, water retention, or oil retention capacities between seed cultivars were detected. This study on non‐digestible carbohydrate components in soybean seed gives a different approach to the current nutritional knowledge on protein and oil constituents.     

Sources of error in dietary fibre analysis

The following error sources in the present dietary fibre (DF) analytical methods were investigated: (1) the omission of the protease treatment of samples may modify the results by increasing the Klason lignin fraction and altering the content and/or distribution of polysaccharides; (2) some soluble dietary fibre (SDF) constituents can be retained in the insoluble dietary fibre (IDF) matrix affecting the insoluble and soluble fraction distribution; (3) protein, ash and blank corrections in gravimetric analysis involve a lack of precision, over- or undervaluing the actual DF contents; (4) the Klason lignin fractions obtained by acid hydrolysis of DF residues are made up of different components and artifacts besides lignin.

These studies included both new observations and additional quantitative evidence on error sources previously mentioned in the literature. In some cases the published methods were modified to emphasize the methodological errors.     

Roasting Effects on Dietary Fiber Composition of Cocoa Beans

The effect of roasting on dietary fiber fractions of cocoa beans was determined by gravimetric and fractionation procedures after enzymatic treatment. Roasting had no notable effect on total dietary fiber content (TDF). Components of insoluble dietary fiber (IDF) became redistributed after roasting. One of the largest changes was a sharp increase of Klason lignin. The noted decrease in sugar content without a change in IDF suggested that neutral sugars and uronic acids may be involved in Maillard polymer formation. Soluble dietary fiber (SDF) did not show large variations. Undigestible protein in IDF increased after roasting.     

Dietary fibre content and antioxidant activity of Manto Negro red grape (Vitis vinifera): pomace and stem

The general composition of two by-products of the vinification process of the Manto Negro red grape (Vitis vinifera) variety, namely pomace and stem, were determined. Both by-products present high contents of total dietary fibre (TDF), comprising three fourths of the total dry matter. The pomace had high protein (12.2%) and oil (13.5%) values and the stem large amounts of extractable polyphenols (11.6%). Due to the high fibre content, the soluble dietary fibre (SDF), insoluble dietary fibre (IDF), uronic acids (UA) and Klason lignin (KL) were analysed in both samples. Notable were the high percentage of soluble fibre (15%) in relation to the total dietary fibre for the pomace, as well as the high content of Klason lignin (KL) in both by-products, especially in the stem (31.6%). This fraction (KL) has important amounts of condensed tannins (CT) and resistant protein (RP).     

Effect of modified dietary fiber extracted from wholegrain wheat on the physicochemical and cake properties

Dietary fiber (DF) extracted from whole wheat was chemically modified by cross-linking (CL), carboxymethylation (CM), and hydroxypropylation (HP) and their physicochemical properties and baking performance were evaluated. CM contributed to the increase in soluble DF (SDF) contents and water solubility. While CL and HP contributed to the decrease in water solubility as insoluble DF (IDF) contents increased. In comparison to the chemically modified DF, CLDF deteriorated textural and physical properties of cakes. On the other hand, the cakes with CMDF and HPDF had improved cake qualities such as appearance, higher volume and lower hardness compared to cake with native DF. Consequently, this study suggested that the chemical modifications of wheat DF can effectively regulate the IDF/SDF ratio and total dietary fiber (TDF) contents, resulting in the change of physicochemical properties of them. When applied to cake, modified wheat DF diversified the physicochemical properties and quality by a functional group.     

Grape Pomace as a Potential Food Fiber

Grape pomace, and insoluble and soluble dietary fiber (DF) fractions, obtained by enzymatic-gravimetric methods, were analyzed for neutral sugars, uranic acids, Klason lignin and amino acids. DF constituted 80% of dry matter, IDF was the major fraction. The main neutral sugar constituent of IDF was glucose. The major part was cellulose and the remainder, along with xylose, was a xyloglucan, which also contained fucose. Uranic acids accounted for 64% of SDF and a high amount of arabinose, galactose and mannose were also included in that fraction. Proteins were not well solubilized by the assay enzymes. During the isolation of DF fractions a considerable solubilization of polyphenols was observed. These compounds were associated with Klason lignin in the starting material. Composition of DF fractions enables grape pomace to be considered a useful fiber-rich food ingredient.     

Effect of processing on the composition of dietary fibre and starch in some legumes

The effect of processing on the total dietary fibre (TDF) insoluble (IDF) and water-soluble (SDF) fractions as well as total (TS), available (AS) and resistant (RS) starch were studied in three legumes, viz. bengalgram (Cicer arietinum L.), Cowpea (Vigna unguiculata) and greengram (Vigna radiata). The processes studied were fermentation, germination, pressure-cooking and roasting. The dietary fibre (DF) content and its components were determined using the enzymatic-gravimetric method. The TS content was determined by the enzymatic method after solubilization with KOH. The DF content ranged from 23.2 to 25.6 g/100 g in the raw and 16.0 to 31.5 g/100 g in the processed legumes. All the processing treatments significantly decreased the SDF content and increased the IDF content of all the three legumes. The mean TS, AS and RS content of the raw legumes were similar, 46.9, 36.7 and 10.2 g/100 g respectively. AS content of all the legumes was reduced by the processing treatments, except pressure cooking. Correspondingly, higher amounts of RS were observed in the processed legumes, except pressure cooked, resulting in an increase in the TDF content.     

Improve the functional properties of dietary fibre isolated from broccoli by-products by using different technologies

The aim of this study was to analyze the chemical composition of leaves, stems and inflorescences obtained from broccoli by-products in order to develop the improvement of the composition and functional properties of DF from broccoli by-products through treatment with different degradation methods, such as modifications with supercritical fluids, enzymatic, autoclave and ultrasound treatment. The results showed that the chemical composition of the different parts of the broccoli by-products, leaves, stems and inflorescences was significantly different, highlighting that the content of insoluble and soluble dietary fibre was higher in the stem. The enzymatic treatments decreased the content of neutral sugars and increased the content of uronic acids, which was related to the increase of specific functional activities. Cellulase and the multi-enzymatic visconzyme complex improved the solubility and glucose adsorption capacity, whereas supercritical fluids treatment improved the swelling, water retention and lipid absorption capacities. The value of non-extractable phenolic compounds was higher in the inflorescences and increased with enzyme and supercritical fluid treatments, as well as the antioxidant capacity. Enzyme treatment also had a greater effect on the stimulation of the growth of the lactic acid bacteria studied and, therefore, reached the highest values in the production of all short-chain fatty acids analysed. Therefore, the use of enzyme treatments of dietary fibre obtained from broccoli by-products improves the functional properties of broccoli fibre.     

Influence of germination on the soluble carbohydrates and dietary fibre fractions in non-conventional legumes

Influence of light exposure during germination on structural and soluble carbohydrates including total dietary fibre (TDF), insoluble dietary fibre (IDF) and soluble (SDF) dietary fibre fractions and also raffinose family oligosaccharides (RFOs) was studied in non-conventional legumes Vigna unguiculata (cowpea), Canavalia ensiformis (jack bean), Stizolobium niveum (mucuna), and Lablab purpureus (dolichos), and compared to a well known and used Glycine max (soybean). Non-conventional legumes were rich in DF, mainly IDF, which represented 93–97% of TDF. It was relevant the proportion of protein that remained associated to the insoluble DF matrix. Non-conventional legumes exhibited important levels of RFOs but their profile was different depending on the tropical seed. The germination of seeds produced changes in the carbohydrate fraction, mainly an increase of TDF in most instances, except for soybean, and a drastic reduction of RFOs, from 98% to 63%, with the corresponding increase in the amounts of total soluble sugars.     

Physicochemical Properties of Dietary Fibres Prepared from Ambarella (Spondias cytherea) and Mango (Mangifera indica) Peels

The preparation of fibres from mango and ambarella peels can offer a way to upgrade by-products. Comparatively to lime, ambarella and mango fibres were prepared from their corresponding peels using ethanolic treatment (85% at 70 °C/5 min). The peels were characterised for their dry matter content, pH and apparent viscosity. The soluble dietary fibre (SDF) and insoluble dietary fibre (IDF) contents of the samples were determined. Hydration capacity of these fibres was evaluated. Results showed that the ethanolic treatment of the peels (85% at 70 °C/5 min) had significant (p?<?0.05) effects on the contents of neutral sugars and uronic acid (from 105 to even 203 mg/g in case of mango fibre). For ambarella fibres, the proportion of IDF (51%) was highest and that of SDF (34%) was lowest. Mango and lime fibres exhibited similar values of IDF (40–43%) and SDF (50–57%). Mango peel fibres had higher hydration capacities than ambarella and lime fibres. The best dietary fibres content and the high hydration capacities of mango peel fibres favour their exploitation in dietary fibre-rich foods preparation.     

Fibre concentrate from mango fruit: Characterization, associated antioxidant capacity and application as a bakery product ingredient

Mango is a still underutilized fruit from tropical regions. The aim of this work was to characterize a mango dietary fibre concentrate (MDF) with antioxidant capacity, using the unripe fruit. MDF was obtained and its chemical composition, soluble (SDF) and insoluble dietary fibre (IDF), extractable polyphenols, water- and oil-holding capacities and anti-radical efficiency, were evaluated. MDF showed low lipid and high starch contents and balanced SDF/IDF levels, which is important for the functionality of fibre in the human diet. MDF exhibited adequate water-holding capacity, similar to other fruit fibres, but had a low oil-holding capacity. Bakery products prepared with MDF conserved the balance of SDF and IDF and most of its anti-radical efficiency. In vitro starch digestibility tests of MDF bakery products indicated a low predicted glycemic index. MDF might be an alternative for development of products with balanced DF components and low glycemic response, aimed to people with special carbohydrate/energy requirements.     

Effects of harvest time and storage on dietary fibre components in various cultivars of white cabbage (Brassica oleracea var capitata)

The effect of harvest time and storage on dietary fibre content and composition was investigated in six cultivars of white cabbage (Brassica oleracea var capitata). Three cultivars were of early maturity type (SW Nordpol, Rolly and Balbro) and three of late maturity type (Predikant, Hanna and Lion). The average total dietary fibre (TDF) content was 241 g kg^?1 dry matter (DM) (CV = 13), of which approximately 25% was soluble (CV = 15). The main dietary fibre components were glucose (37%), uronic acid (32%), arabinose (12%) and galactose (8%) residues. Early cultivars generally had a lower TDF content than late maturity types, due to a lower amount of both insoluble (arabinose, galactose and glucose) and soluble (arabinose) polymers. An early cultivar, Rolly, had the highest solubility, 33%, versus 25 ± 4% for the other cultivars. The early cultivar SW Nordpol had a similar TDF content and proportion of soluble dietary fibre (SDF) to the late cultivar Hanna, but the dietary fibre composition was different, with the early cultivar having a lower proportion of arabinose residues. Storage for 6 weeks had minor effects on the dietary fibre. After further storage of the late maturity cultivars, there was an increase in insoluble dietary fibre (IDF) (glucose and uronic acid residues) and a decrease in SDF (arabinose and galactose residues). As a consequence the solubility of TDF decreased from 29 to 19% on average. Harvesting before physiological maturity was reached resulted in a somewhat lower content of TDF and IDF for two cultivars (Predikant and Hanna), while SDF was more or less unaffected for all cultivars. Long‐term storage had fewer effects on cabbage harvested prior to maturity than when harvested at the right physiological maturity. It is concluded that the observed differences between cultivars and after long term storage are of such magnitude that they may affect nutritional properties of the dietary fibre. © 2002 Society of Chemical Industry     

复合酶法制取柠檬皮渣膳食纤维的研究

以柠檬皮渣为原料,使用酶解法制备柠檬膳食纤维。在不同酶制剂用量、酶解时间、酶解温度和pH值条件下制备柠檬膳食纤维,并测定可溶性膳食纤维(SDF)/不溶性膳食纤维(IDF)比值和理化指标。结果表明：柠檬皮渣在1%的酶用量,酶解时间12 min,酶解温度60 ℃,pH值为6的条件下处理时,得到的柠檬膳食纤维产品SDF/IDF为0.67,总黄酮含量为4.82 mg/100 g,VC含量为247 mg/100 g,白度L*为90.23,黏度为7.57 mPa·s,产品质量较优。 关键词：中图分类号：TS255.36 文章编号：0254-5071（20１6）04-0181-04 doi:     

油茶粕膳食纤维的超声辅助酶法提取工艺优化及理化性质分析

膳食纤维（Dietary Fiber，DF）具有很多生理功能及突出的应用前景，而可溶性膳食纤维（Soluble Dietary Fiber，SDF）的生理特性要优于不溶性膳食纤维（Insoluble Dietary Fiber，IDF）。为提高油茶粕DF中SDF的得率，以SDF得率作为评价指标，采用超声辅助酶法，通过单因素实验对酶添加量、超声时间、超声功率、料液比四个因素进行研究，并在单因素实验的基础上进行响应面优化试验，并对得到的DF进行理化性质及结构分析。结果表明，最佳提取工艺为酶添加量0.2%、超声时间31 min、超声功率210 W、料液比1:23 g/mL，SDF得率为12.43%，此时IDF得率为68.39 %。油茶粕总膳食纤维（Total Dietary Fibre，TDF）的持水力为4.36 g/g、持油力为3.67 g/g、膨胀力为6.83 mL/g，胆固醇吸附率在pH2时为5.79 mg/g，pH7时为8.38 mg/g，葡萄糖吸附率为11.49 mg/g。通过结构表征的分析推测油茶粕TDF中含有木质素、纤维素、半纤维素及糖类物质，TDF表面疏松多孔、凹凸不平，粒径为50.699 nm。本研究提高了SDF得率，证明油茶粕TDF具有较好的理化性质及结构，为提高油茶粕的附加价值提供了参考。     

Characterisation of peach dietary fibre concentrate as a food ingredient

Insoluble and soluble dietary fibre (DF) fractions of peach DF concentrate, obtained by an enzymatic-chemical method, were analysed for neutral sugars, uronic acids and Klason lignin. Proximate composition, energy value, colour and water- and oil-holding capacities were also determined. Total DF constituted 31–36% dry matter (DM) of the concentrate and insoluble DF was its major fraction (20–24% DM). The high proportion of soluble fraction (11–12% DM) in the peach DF concentrate, in comparison with cereal brans, was noticeable. Insoluble and total dietary fibre contents significantly decreased throughout the harvest time of the original fresh fruit. Results suggested that peach DF concentrate may be not only an excellent DF source but an ingredient in the food industry because it showed a high affinity for water (9.12–12.09 g water/g fibre) and low energy (3.723–3.494 kcal/g). However, the use of this material could affect the colour and pH of the final product.     

Effects of pretreatment methods on health-related functional properties of high dietary fibre powder from lime residues

Epidemiological studies have revealed that consumption of dietary fibre (DF) leads to many health benefits. Lime residues, which are by-products obtained after juice extraction, were used as raw material to produce DF powder. The residues are high in DF and possess a good balance between insoluble dietary fibre (IDF) and soluble dietary fibre (SDF). To process lime residues into value added products, some treatments prior to drying are required to reduce the bitterness, and this may affect the functional and nutritional properties of DF powder. This study investigated the effects of pretreatment methods of blanching, blanching-ethanol soaking (95% v/v for 30 min) and particle size reduction (38–450 μm) on selected health related functional and nutritional properties of DF from lime residues. The lime residues were dried at 60 °C before grinding. The functional and nutritional properties of interest included glucose adsorption capacity (GAC), glucose retardation index (GRI) and bile acid retardation index (BRI). The results show that DF powder prepared either by blanching or blanching followed by ethanol soaking prior to drying exhibited higher GRI and BRI. The pretreatments, however, did not affect the GAC. DF powder with smaller sizes also possessed higher GRI and BRI. The DF product with particle size in the range of 38–63 μm, and pretreated by blanching and ethanol soaking exhibited the highest GRI and BRI among all samples studied.     

Composition of dietary fibre in cocoa husk

 This paper describes the total non-starch polysaccharide (NSP), soluble and insoluble dietary fibre (SDF and IDF) content of processed cocoa husk (cocoa butter <3 g/100 g) determined according to Englyst's enzymatic-chemical procedure. In addition, fibre values were determined by measuring the levels of the composite sugars by spectrophotometry and gas chromatography methods, and the fractions acid-detergent fibre, neutral-detergent fibre, crude fibre, Klason lignin, starch, crude protein, ash, fat, water content, and water-holding capacity (WHC). The NSP content was 43.8±2.32 g/100 g (28.34 g/100 g IDF plus 15.60 g/100 g SDF), the mean soluble fibre concentration was 35.5% of total fibre. Klason lignin content, estimated gravimetrically, was 13.7±1.8 g/100 g. Cellulose (19.7±1.48 g/100 g) and uronic acids (12.4±1.35 g/100 g) were the main type of IDF and SDF substances, respectively. The analysis of neutral sugar constituents showed the presence of glucose, the predominant sugar, followed by arabinose, galactose and xylose. The WHC was 3.62±0.47 g water/g cocoa husk. Received: 19 December 1997 / Revised version: 27 February 1998     

Composition of dietary fibre in cocoa husk

 This paper describes the total non-starch polysaccharide (NSP), soluble and insoluble dietary fibre (SDF and IDF) content of processed cocoa husk (cocoa butter <3 g/100 g) determined according to Englyst's enzymatic-chemical procedure. In addition, fibre values were determined by measuring the levels of the composite sugars by spectrophotometry and gas chromatography methods, and the fractions acid-detergent fibre, neutral-detergent fibre, crude fibre, Klason lignin, starch, crude protein, ash, fat, water content, and water-holding capacity (WHC). The NSP content was 43.8±2.32 g/100 g (28.34 g/100 g IDF plus 15.60 g/100 g SDF), the mean soluble fibre concentration was 35.5% of total fibre. Klason lignin content, estimated gravimetrically, was 13.7±1.8 g/100 g. Cellulose (19.7±1.48 g/100 g) and uronic acids (12.4±1.35 g/100 g) were the main type of IDF and SDF substances, respectively. The analysis of neutral sugar constituents showed the presence of glucose, the predominant sugar, followed by arabinose, galactose and xylose. The WHC was 3.62±0.47 g water/g cocoa husk. Received: 19 December 1997 / Revised version: 27 February 1998