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.     

Characteristics of fibre‐rich powder and antioxidant activity of pitaya (Hylocereus undatus) peels

The contents of total dietary fibre (TDF), soluble dietary fibre (SDF), insoluble dietary fibre (IDF) and functional properties of fibre‐rich powders (FRP) from pitaya peels with different particle size (FRP80, FRP140 and FRP250) were determined. Results showed that FRP140 had higher TDF (79.37%) and SDF (33.07%) with a balanced ratio of SDF/IDF (1:1.32) and higher water‐holding capacity (54.20 g g^?1), swelling capacity (50.63 mL g^?1), oil‐holding capacity (2.65 g g^?1) and glucose dialysis retardation index (62.83% at 60 min), compared with FRP80 and FRP250. Therefore, physiochemical properties of FRP140 were further investigated. SDF of FRP140 mainly contained rhamnose (4.95%) and galactose (1.98%), with 9.45% galacturonic acid, while IDF dominantly contained xylose (4.76%) and galactose (3.42%), with 18.54% klason lignin. Total phenolic content was 7.75 mg g^?1 and mainly composed of salicylic acid (0.98 mg g^?1) and protocatechuic acid (0.45 mg g^?1). Furthermore, FRP140 showed significant reducing power, DPPH‐scavenging activity and nitrite‐scavenging ability.     

Effect of rice bran fibre on the quality of rice pasta

This study investigated the effects of rice bran fibre (RBF) on the properties of rice pasta by extrusion processing. As the level of RBF increased, the content of total dietary fibre (TDF), insoluble dietary fibre (IDF) and soluble dietary fibre (SDF) increased, respectively. The difference in the content of ΔIDF between before and after extrusion decreased from 1.01% to 0.69% and that of ΔSDF decreased from 1.06% to 0.55%. Depending on the increasing level of RBF, the water absorption index decreased and water solubility index increased, respectively. The crystallinity of newly formed crystals decreased from 21.43% to 18.66% as the level of RBF increased. Adding RBF darkened the colour of rice pasta and reduced its hardness and chewiness. The cooking loss (CL) increased significantly compared with the control (0% RBF). The results indicate that rice pasta with extra RBF (up to 15%) can provide an acceptable quality product with a satisfactory colour and CL.     

Diferulates as structural components in soluble and insoluble cereal dietary fibre

Cell wall cross‐linking can have a substantial effect on the properties of the wall. To estimate cross‐linking (between arabinoxylans) in cereal fibres, dehydrodiferulate levels were measured in soluble and insoluble dietary fibre (SDF and IDF) isolated from whole grains of maize (Zea mays L), wheat (Triticum aestivum L), spelt (Triticum spelta L), rice (Oryza sativa L), wild rice (Zizania aquatica L), barley (Hordeum vulgare L), rye (Secale cereale L), oat (Avena sativa L) and millet (Panicum miliaceum L). After saponification of the cereal fibres the extracts were investigated for dehydrodimers of ferulic acid using GLC–MS and GLC–FID. From most cereal IDF the whole spectrum of dehydrodiferulic acids (DFAs) (8‐5′‐, 8‐8′‐, 5‐5′‐, 8‐O‐4′‐ and 4‐O‐5′‐coupled) could be identified. The absolute contents of total DFAs ranged between 2.4 and 12.6 mg g^?1. With the exception of 4‐O‐5′‐coupled DFA, the whole range of DFAs was also detected from cereal SDF but only in amounts of 40–230 µg g^?1. It was estimated that arabinoxylans of cereal IDF contain 8–39 times more diferulates than arabinoxylans of cereal SDF (where measurement of DFA levels in SDF was possible). In cereal IDF, 8‐5′‐coupled dimers dominated, whereas in cereal SDF, 8‐8′‐coupled dimers were relatively enhanced and often became the major dimers. © 2001 Society of Chemical Industry     

Effect of Heat Treatments on Chemical Analysis of Dietary Fiber

Apple fiber, corn fiber, oat bran and soy fiber were analyzed to study the effect of heat processing (autoclaving at 121°C/15 min, 100°C/30 min and microwave heating for 5/10 rain) on dietary fiber fractions. Samples were analyzed for insoluble (IDF), soluble (SDF), and total dietary fiber (TDF) by an enzymatic-gravimetric method. Autoclaving reduced IDF of apple fiber and TDF of apple fiber and oat bran. Microwave heating reduced TDF in apple fiber and oat bran and IDF in oat bran but increased the SDF of apple fiber. All treatments decreased the SDF in corn fiber. Effects on dietary fiber fractions depended on fiber type and processing method.     

Dietary fiber profile of barley flour as affected by extrusion cooking

Barley grains, Phoenix and CDC-Candle, were extruded in a twin-screw extruder at 90−140 °C and 20–50% moisture level. Effects of extrusion conditions on total (TDF), soluble (SDF), and insoluble dietary fiber (IDF) were determined. The content of SDF and TDF increased upon extrusion cooking of both types of barley flours. The changes in IDF content were found to be variety-dependent. Only a minor decrease in IDF content of CDC-Candle barley was found, but an increase in IDF content of Phoenix was observed at all extrusion temperatures. The increase in SDF, in both barleys, could be due to the transformation of some IDF into SDF during extrusion and the formation of additional SDF by transglycosidation. The increase in IDF in Phoenix flour could be due to the formation of retrograded amylose [resistant starch (RS3)] during extrusion cooking and subsequent cooling.     

Composition,Rheological and Extrusion Behaviour of Fractions Produced by Three Successive Reduction Dry Milling of Corn

The composition, rheological and extrusion behaviour of three fractions, i.e. coarse (>500 μm), medium-coarse (300–500 μm) and fine (<300 μm), obtained from three successive reduction dry milling of corn was studied. Fractions from different reduction stages vary in composition, pasting and structural characteristics. All the fractions from third reduction stage had higher protein, lipid, ash and b* value while with lower crystallinity and L* value. These fractions also showed higher pasting temperature and lower breakdown viscosity than the fractions from first and second reduction stages. The characteristics of extrudates varied with the composition as well as particle size of the fractions. The fractions with higher lipid and protein content resulted into extrudates with lower water solubility index (WSI) and expansion; however, fine fractions resulted into extrudates with higher WSI and expansion.     

Effects of enzymatic/alkali protein removal and particle size reduction on physicochemical and functional characteristics of okara dietary fibre

The combined effects of enzymatic/alkali protein removal treatments and superfine grinding on the characteristics of okara dietary fibre (DF) were investigated. Protein removal could effectively increase the obtained DF content and further enhance water-holding capacity (WHC), swelling capacity (SC) and oil-holding capacity (OHC). The DF with Alcalase treatment and superfine grind through 500-μm mesh size had the highest total dietary fibre, WHC (12.5 g g⁻¹), SC (12.7 mL g⁻¹) and OHC (2.7 g g⁻¹). Decreasing particle size will trigger a redistribution of some fibre composition from the insoluble to the soluble fraction. The WHC and SC of the sieved DFs decreased with reducing mesh size (500–40 µm). The OHC of DF with Flavourzyme treatment reduced with decreasing mesh size (500–100 µm), but improved with mesh size less than 100 µm.     

Effect of micronised oat bran by ultrafine grinding on dietary fibre,texture and rheological characteristic of soft cheese

The purpose of this research was to study the effect of micronised oat bran on dietary fibre, textural and rheological of soft cheese. The soft cheese was processed by using the different particle size oat bran as fibre supplement, and its dietary fibre content, rheological and textural properties were determined. The results show that the micronised oat bran with 5–30 μm particle size was prepared by ultrafine grinding and passed through 60–400 mesh sieves. The soluble dietary fibre content in micronised oat bran soft cheeses was higher than that of the control (untreated oat bran soft cheeses; P < 0.05), with a maximum of 2.65 g per 100 g cheeses when oat bran was ultrafine crushed and passed through 300 mesh sieves, while the content of insoluble dietary fibre was lower than that of the control (P < 0.05). The micronised oat bran soft cheese in fermentation is a typical non-newtonian fluid. G′, G″ and apparent viscosity of soft cheeses were increased with the reduction of oat bran particle size. The chewiness and springiness of micronised soft cheeses were increased with the reduction of oat bran particle size, and were higher than that of the control (P < 0.05). The hardness and cohesiveness of micronised soft cheese were decreased with the reduction of oat bran particle size, the hardness was lower, but the cohesiveness of micronised soft cheese was higher than that of the control (P < 0.05). The 1% micronised oat bran can obtain better processing characteristics and overall acceptability for cheese products.     

Physicochemical characterisation of corn extrudates prepared with varying levels of beetroot (Beta vulgaris) at different extrusion temperatures

This study examines the effect of beetroot powder (BRP) incorporation (0%, 5%, 10% and 15%) at different extrusion temperatures (125, 150 and 175 °C) on the physicochemical, antioxidant and sensory properties of corn grit (CG) extrudates. BRP showed higher values of total phenolic content (TPC = 9095 μg GAE g^?1) and free radical inhibition (ABTS = 6.5 μm trolox mg^?1 and DPPH = 7.9 μm trolox mg^?1) than CG (1346 μg GAE g^?1, 1.5 μm trolox mg^?1 and 2.2 μm trolox mg^?1, respectively). Pasting viscosity (peak, breakdown and final) decreased, while pasting temperature of CG increased with the level of BRP incorporation. Analyses of the extrudates showed an increase in redness, bulk density, hardness, TPC, free radical inhibition, total dietary fibre (TDF) and a decrease in water absorption index (WAI), water solubility index (WSI), expansion ratio and oil uptake with the increase in the level of BRP incorporation. On the other hand, higher extrusion temperature increased porosity, WAI, WSI, oil uptake but decreased redness, bulk density, hardness and TPC.     

Modification of barley dietary fiber through chemical treatments in combination with thermal treatment to improve its bioactive properties

The present research was carried out to observe the comparative effectiveness of different chemical treatments in combination with simultaneous thermal treatment on soluble (SDF) and insoluble dietary fiber (IDF) ratio to improve functional properties of barley. For this purpose, two varieties of barley, i.e., Haider-93 and Jau-87 were assessed for chemical composition, mineral, non-starch polysaccharides, and dietary fiber contents through respective methods. Two varieties were chemically treated through acid, alkaline, and consecutive acid–alkaline treatments in combination with thermal treatment. Results of chemical composition revealed that Jau-87 was higher in moisture (11.4%), crude fat (2.67%), and crude fiber (4.70%), whereas Haider-93 exhibited higher ash (2.56%) and crude protein content (12.7%). Moreover, barley is a rich source of potassium ranging from 4.77 to 5.07 g/kg. Likewise, main non-starch polysaccharides in barley were arabinoxylan (3.60–3.77%) and beta-glucan (3.65–3.67%). Furthermore, barley contains more IDF (12.00–12.40 g/100 g dm) than SDF (4.73–5.70 g/100 g dm). Additionally, modification of SDF (23.68%) and IDF (11.69%) ratio through acid treatment was nonsignificant, while acid–alkaline treatment showed highly significant results, i.e., 771.46% increased in SDF and 53.39% decreased in IDF. It is concluded that chemical treatments alone or in combination with pressure cooking increased SDF. However, simultaneous effect of acid and alkaline treatment most effectively increased the solubility of barley.     

超高静压改性麦麸对其功能性质的影响

本实验以小麦麸皮为原料,采用单因素试验研究麦麸粒度、处理时间、处理压强和改性麦麸质量分数对小麦麸皮功能性质的影响,通过扫描电子显微镜和傅里叶变换红外光谱仪分析了麦麸改性前后的超微结构和官能团。结果：在麦麸粒度40 目、处理时间20 min、压强400 MPa、麦麸质量分数20%条件下,麦麸可溶性膳食纤维质量分数最高、阳离子交换能力最强、脂肪酶活力最低;在麦麸粒度50 目、处理时间15 min、压强400 MPa、麦麸质量分数20%条件下,麦麸持水力和持油力较高;在麦麸粒度40 目、处理时间25 min、压强300 MPa、麦麸质量分数15%条件下,麦麸亚硝酸根清除率较强;在麦麸粒度50 目、处理时间25 min、压强500 MPa、麦麸质量分数25%条件下,麦麸胆固醇吸附能力较强。扫描电子显微镜观察结果显示超高静压破坏了麦麸膳食纤维的结构,使其结构变得疏松,傅里叶变换红外光谱分析结果表明超高静压可以破坏分子间的共价键,使纤维素降解,不溶性膳食纤维转化为可溶性膳食纤维。通过本实验改性的麦麸具有较好的功能特性,有很好的应用前景。     

Impact of cell wall‐degrading enzymes on water‐holding capacity and solubility of dietary fibre in rye and wheat bran

BACKGROUND: Rye and wheat bran were treated with several xylanases and endoglucanases, and the effects on physicochemical properties such as solubility, viscosity, water‐holding capacity and particle size as well as the chemical composition of the soluble and insoluble fractions of the bran were studied. A large number of enzymes with well‐defined activities were used. This enabled a comparison between enzymes of different origins and with different activities as well as a comparison between the effects of the enzymes on rye and wheat bran. RESULTS: The xylanases derived from Bacillus subtilis were the most effective in solubilising dietary fibre from wheat and rye bran. There was a tendency for a higher degree of degradation of the soluble or solubilised dietary fibre in rye bran than in wheat bran when treated with most of the enzymes. CONCLUSION: None of the enzymes increased the water‐holding capacity of the bran or the viscosity of the aqueous phase. The content of insoluble material decreased as the dietary fibre was solubilised by the enzymes. The amount of material that may form a network to retain water in the system was thereby decreased. © 2012 Society of Chemical Industry     

Improved function of bamboo shoot fibre by high-speed shear dispersing combined with enzyme treatment

With the increase in global welfare, metabolic syndrome-related diseases seriously disrupt our quality of life. Balanced diet with low calories, low glycaemic index, and high dietary fibre such as bamboo shoot fibre is needed. Functional properties of dietary fibre can be improved by processing methods. Therefore, we compared the effect of three processing methods (high-speed shear dispersing, enzyme treatment and combined treatment) on the characteristics and functions of bamboo shoot fibres. Combined treatment resulted in high SDF content (10.15%), adsorption capacity of glucose (4.45–18.18 mmol g⁻¹), nitrite ion (505.49 μg g⁻¹ [pH 2.0]), and cholesterol (333.72 μg g⁻¹ [pH 2.0]). FTIR revealed that hydroxyl groups, sugar methylene and benzene rings of aromatic compounds existed in the treated bamboo shoots. The particle size (D₅₀) decreased from 383.90 to 30.65 μm. Honeycomb-like structure was also observed through SEM. Thus, proper processing of bamboo shoot fibres can improve their functions as food ingredients.     

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.     

Effect of the Sugar Replacement by Citrus Fibre on the Physical and Structural Properties of Wheat-Corn Based Extrudates

Citrus fibre was used as a substitute for sucrose in the formulation of wheat-corn-based extrudates produced using twin screw extruder. Replacing 5 % sugar with an equal quantity of fibre resulted in an increase in die pressure, torque and specific mechanical energy (SME), and consequently the expansion ratio increased. A further increase in fibre content to 10 % (e.g. reducing sugar to 0 %) had little effect on the extrusion processing parameters. The microstructure of extrudates examined by X-ray computed tomography shows that the porosity of the extrudates increased with increasing fibre content, which was attributed to an increased number of large pores. As the citrus fibre content increased, the maximum force required to fracture the extrudate increased; however, the cell wall thickness decreased. This suggests that the fibre component may have contributed to the strength of the cell wall. This study demonstrated a potential utilisation of fibre from by-product of juice extraction as a source of dietary fibre in low sugar-extruded products.     

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     

苦荞中可溶性及不可溶性膳食纤维调控糖尿病小鼠糖脂代谢的功效

本研究采用苦荞麸皮粉中提取的膳食纤维对高脂/链脲佐菌素诱导的糖尿病小鼠进行干预,比较苦荞麸皮粉中的可溶性膳食纤维（soluble dietary fiber,SDF）和不可溶性膳食纤维（insoluble dietary fiber,IDF）的含量及作用差异,解析苦荞中SDF及IDF对调控糖尿病小鼠血糖及血脂代谢作用的贡献。结果：苦荞麸皮中IDF的质量分数（（19.52±0.21）%）约为SDF（（4.02±0.19）%）的5 倍;相同干预剂量下SDF比IDF能更有效地发挥降血糖作用,但当IDF干预剂量达到SDF的5 倍时,IDF降低血清中的总胆固醇和低密度脂蛋白胆固醇水平的效果更显著（P＜0.05）,并且能够和SDF一样有效促进胰岛素分泌并改善糖耐量、降低肝脏中总胆固醇水平、促进短链脂肪酸的产生。结论：苦荞SDF和IDF均具有改善糖耐量、降低血清及肝脏中脂肪积累的功效,且都与盲肠中短链脂肪酸含量的增加密切相关;研究揭示了苦荞SDF及IDF在量效关系上的差异,为充分理解谷物中不同膳食纤维的糖脂调控功效提供了科学证据。     

High Hydrostatic Pressure and Mild Heat Treatments for the Modification of Orange Peel Dietary Fiber: Effects on Hygroscopic Properties and Functionality

Fruit by-products, such as orange peels, are non-conventional sources of dietary fiber (DF) suitable for developing food ingredients with novel applications. Orange peels were processed at 600 MPa (come up time–CUT, 2, 5, 10, or 20 min) and two temperatures (55 or 70 °C) with the aim to study changes in total (TDF), soluble (SDF), and insoluble (IDF) dietary fiber contents, water-/oil-holding capacity (WHC/OHC), solubility, swelling capacity (SC), pH, tap density, and hygroscopic properties. Increments of 1.9 times on the SDF content were observed after HHP treatment at 55 and 70 °C, compared to the untreated sample content (7.17% dw). Constant values of TDF (51.2–54.6% dw) suggested the significant conversion of assayable IDF to SDF. An increase on SC (6.5%) and OHC (20.1%) values were observed in samples treated with CUT at 70 and 55 °C, respectively. Compared to control samples, HHP (55 °C/5 min) exerted changes on moisture isotherms expressed as relative water sorption content. HHP improved the adsorption and desorption water retention of samples in the 0.1–0.93 a _w range studied. Results indicate that HHP combined with heat treatment has potential to modify the functionality of orange peels with short processing times.     

火龙果皮中膳食纤维含量及其物理化学特性

以火龙果果皮为原料,制备3种不同粒径的火龙果高膳食纤维果皮粉(DFRPP)：DFRPP80、DFRPP140和DFRPP250,测定其总膳食纤维、可溶性和不溶性膳食纤维含量,并对其持水性、持油性、溶胀性和对葡萄糖的透析阻滞能力进行研究。结果表明：粒径为58～104μm的DFRPP140中总膳食纤维和可溶性膳食纤维含量最高,分别为79.37%和33.07%,其可溶性膳食纤维与不溶性膳食纤维具有良好的比例模式,且其持水性、持油性和溶胀性最强,分别为54.20g/g、2.65g/g和50.63mL/g;其对葡萄糖的透析阻滞系数最好,在20、40、60min时分别是60.24%、59.24%和62.83%。DFRPP140可作为食品膳食纤维的优良来源。