Improvement of the functionality of a potential fruit insoluble fibre by micron technology

An insoluble food fibre was micronised to different microsizes (6.77–29.5 μm) by three different micron technologies using optimised conditions. The effects of different micronisation treatments and particle sizes on the characteristics and various physicochemical properties of this insoluble fibre were studied. As particle size decreased, the bulk density of the insoluble fibre was significantly (P < 0.05) decreased. A redistribution of fibre components from insoluble to soluble fractions was observed. The treatments, especially the high‐pressure micronisation, effectively (P < 0.05) increased the physicochemical properties (e.g. water‐holding capacity, swelling capacity, oil‐holding capacity, cation‐exchange capacity and glucose‐adsorption capacity) and also the inhibitory activity towards α‐amylase and pancreatic lipase of the insoluble fibre to different extent (from several up to c. fifteenfold). Our results suggested that micronisation treatments would provide an opportunity to improve the functionality of the insoluble fibre and exploit its potential applications as a functional ingredient in fibre‐rich products.     

Effect of micronisation on dietary fibre content and hydration properties of lotus node powder fractions

Fibre‐rich fractions were obtained from nodes of lotus root and micronised by nine different ball‐milling treatments. The optimum milling conditions were screened out by comparing its effects on physicochemical and hydration properties of micro‐sized particles of lotus node powder fraction (LNPF). The micronisation by ball‐milling treatments was carried out at different speeds (200–400 r min^?1) and time (4–12 h). Ball‐milling treatments could effectively (P < 0.05) pulverise the LNPF particles to different micro‐sizes. As particle size decreased, a redistribution of fibre components from insoluble to soluble fractions was observed. Furthermore, micronisation treatments, especially 12 h at 300 r min^?1, could significantly (P < 0.05) increase the hydration characteristics, as well as impart lightness in colour to different extents. Our findings suggested that micronisation can improve physicochemical and hydration characteristics of the fibre components, which provide an opportunity to improve the utilisation and application of lotus node dietary fibre.     

Effects of particle size reduction of insoluble fibres by micron technology on various caecal and faecal indices

BACKGROUND: Previous findings demonstrated that particle size reduction of insoluble fibre materials (i.e. starfruit insoluble fibre‐rich fraction and cellulose) to micro‐sizes effectively enhanced their physicochemical properties, which provided clues to their physiological functions. The aim of the present study was to investigate the effects of particle size reduction of these insoluble fibres by micron technology on indices of bowel health. RESULTS: Feeding of the micronised fibres (9.68–14.3 µm), especially those prepared by high‐pressure micronisation, effectively (P < 0.05) improved various caecal and faecal indices, such as decreasing the caecal ammonia concentration (by 20.0–30.0%), increasing the faecal output (135–150%) and moisture content (143–157%) and lowering the activities of undesired β‐D ‐glucosidase (by 39.2–43.6%) and β‐D ‐glucuronidase (by 71.4–77.5%) in faeces of hamsters. Relationships between physicochemical properties and physiological functions of the micronised fibres were considered. The results also demonstrated that the type, processing and related particle size of insoluble fibres were important factors affecting their physicochemical properties and physiological functions. CONCLUSION: The consumption of micronised insoluble fibres at 5% level might exert a favourable effect on improving various caecal and faecal indices. The results of this study provide some hints on potential applications of micron technology in the food industry. Copyright © 2007 Society of Chemical Industry     

Different micronization methods significantly improve the functionality of carrot insoluble fibre

This study was to investigate the effects of different micronization methods, including ball milling, jet milling and high-pressure micronization on the characteristics and various functional properties of carrot insoluble fibre-rich fraction (FRF). The results demonstrated that these treatments could effectively (p < 0.05) pulverize the fibre particles to different micro-sizes. As particle size decreased, the bulk density of the insoluble FRF was significantly (p < 0.05) decreased and a redistribution of fibre components from insoluble to soluble fractions was observed. Furthermore, these treatments, especially the high-pressure micronization, could significantly (p < 0.05) increase the physicochemical properties (e.g., water-holding capacity, swelling capacity, oil-holding capacity and cation-exchange capacity), glucose adsorption capacity, -amylase inhibitory activity and pancreatic lipase inhibitory activity of the insoluble FRF to different extents (from several to 29-fold). Our findings suggested that these micronization treatments would provide an opportunity to improve the functionality of carrot insoluble FRF in food applications.     

Supplementation of pig diet with algal fibre changes the chemical and physicochemical characteristics of digesta

Seaweed extracts, because of their physicochemical characteristics and potential nutritional value, could provide a new source of dietary fibre. This study investigated changes in seaweed fibres (physicochemical and fermentative properties) in different digestive sites and their effects on digesta (viscosity and hydration properties). Sixteen pigs were adapted to a test diet supplemented with 5% algal fibre (either Palmaria palmata (PP), a poorly viscous soluble xylan; or Eucheuma cottonii (EC), a partly insoluble carrageenan; or Laminaria digitata (LD), a highly viscous soluble alginate) or 5% cellulose (reference fibre). PP did not modify the characteristics of digesta and was fermented in the caecum (pH 6.1 ± 0.4; short‐chain fatty acids measured in digesta, 1409 ± 691 µmol g⁻¹ dry matter). EC and LD were mainly insoluble in the stomach, becoming soluble in the intestine; EC was slightly fermented in the colon, giving a low concentration of short‐chain fatty acids (303 ± 122 µmol g⁻¹ dry matter). Supplementation of the diet with alginate (LD) increased 3.5‐fold the ileal viscosity of digesta and their hydration capacity in the ileum and colon. Thus the physicochemical properties of pig digesta largely depend on the physicochemical properties of the ingested seaweed fibre, the pH and ionic conditions prevailing in the gut, and their fermentability. © 2000 Society of Chemical Industry     

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.     

高能机械处理方法对大豆不溶性膳食纤维结构及理化特性的影响

为比较高能机械处理方法对大豆不溶性膳食纤维的改性作用,本文分别采用振荡球磨与微射流均质技术对大豆不溶性膳食纤维进行微细化处理,研究了两种方法对膳食纤维结构及理化特性的影响。研究结果表明,大豆膳食纤维经球磨与微射流处理后,颗粒分别呈现弥散状形态与丝簇状形态,平均粒径为28.06、7.34 μm,为未处理组的22.83%、5.97%;微射流均质可降解大豆膳食纤维的晶体结构,相对结晶度由40.98%下降为3.16%,并形成具有较多分子间氢键的纤维丝簇,属于无定形的β-纤维素晶体结构。进一步研究发现,微射流均质比较球磨处理能明显提高大豆膳食纤维的持水率与持油率,分别为未处理组的2.96、2.48倍。纤维素微纤丝水凝胶具有更高的振荡稳定性,tan δ为空白样的20.73%,这可能与微纤丝较强的成氢键能力以及形态上缠绕形成较大的空间位阻有关。     

Water‐holding capacity of insoluble fibre decreases free water and elevates digesta viscosity in the rat

BACKGROUND: The relationships between possible physiological properties of insoluble fibre and the viscosity of digesta are poorly understood. The aim of this study was to investigate the effect of insoluble fibres with different water‐holding capacity, swelling, oil‐holding capacity and cation exchange capacity on gastric, small intestinal and caecal contents in rats fed a semi‐purified diet containing either no fibre (control), 50 g kg^?1 tossa jute fibre or 50 g kg^?1 shiitake fibre. RESULTS: The water‐holding capacity, swelling, oil‐holding capacity and cation exchange capacity of insoluble fibres of tossa jute were higher than those of shiitake (P < 0.001). The order of the viscosities of digesta was control group < shiitake fibre group < tossa jute fibre group in gastric, small intestinal and caecal contents (P < 0.05). The digesta viscosity at a shear rate of 40 s^?1 was strongly correlated with the free water content of digesta (r = ? 0.89; P < 0.01). The free water content of digesta depended on the water‐holding capacity of insoluble fibres represented as a linear function with negative slope (P < 0.001). CONCLUSION: The viscosity of digesta depends on the free water content, and this is reduced by fibre that holds water and can swell. Copyright © 2008 Society of Chemical Industry     

Influence of the dehydration process on active compounds of okara during its fractionation

Okara (residue of the soymilk manufacture) is rich in proteins, fibres and lipids. It also contains isoflavones that possess health‐promoting properties. A new method has been developed for the valorization of fibres from okara by hydrolysis of insoluble proteins with a protease and removal of the oil. Three different processes were investigated: the first one involved delipidation and drying prior to proteolysis and led to the highest content of fibre (80%) in the final product. The second used proteolysis on crude okara followed by solvent delipidation–dehydration and gave an intermediate content of fibre (75%). The last process was totally enzymatic (proteolysis and lipolysis) and gave the lowest content of fibre in the final product (50%). Fibre water‐holding capacity was correlated to the total dietary fibre content of each sample. It was preferable to use crude okara for hydrolysis, since oven‐drying during the process decreased the water‐holding capacity and modified the isoflavone profile of okara. Copyright © 2005 Society of Chemical Industry     

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     

不同粒径对青稞麸皮结构与功能特性及冲调稳定性的影响

青稞麸皮是膳食纤维的丰富来源,然而其口感粗糙,目前在食品工业中的应用不足10％.超细研磨技术是一种能有效提升食品原料利用价值的新兴技术.本研究采用新型的气流冲击磨技术对青稞麸皮进行处理,得到了4组平均粒径不同的青稞麸皮,分别是粗青稞麸皮(coarse highland barley bran,CHB)、中青稞麸皮(me...     

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.     

小米麸皮膳食纤维成分及物化特性测定

本试验采用酶-化学法提取糯性小米麸皮、非糯性小米麸皮中的膳食纤维,对其化学成分、单糖组成进行分析,并对提取出的膳食纤维进行物化特性测定,包括膨胀力、持水力、持油力等。结果表明,糯性麸皮中膳食纤维质量分数达到76.58%,其中不溶性膳食纤维为69.09%,可溶性膳食纤维为7.49%;非糯性小米麸皮中膳食纤维质量分数为73.18%,其中不溶性膳食纤维为65.55%,可溶性膳食纤维为7.63%;提取出的糯性和非糯性小米麸皮膳食纤维中不溶性膳食纤维质量分数分别达到91.35%、89.55%。且从小米麸皮中提取出来的膳食纤维均具有良好的物化特性3,7℃下,糯性小米麸皮膳食纤维和非糯性小米麸皮膳食纤维膨胀力分别为4.80、4.61 mL/g。这些都标示着小米麸皮可作为富含大量优质膳食纤维的潜在来源。     

Influence of Oven-Drying Temperature on Physicochemical and Functional Properties of Date Fibre Concentrates

Agri-food by-products rich in dietary fibres may be used as feeds and health foods. Owing to its high fibre content, date flesh could be useful in human nutrition. It is interesting to study the influence of oven-drying temperatures of date fibre concentrates (DFC) on their physicochemical and functional properties for possible use as a potential fibre source in the enrichment of food. DFC from 11 Tunisian date cultivars were dried at different temperatures (40, 50 and 60 °C) and analysed regarding proximate composition (moisture, ash, protein and lipids), physicochemical (water activity (a _w), pH) and functional properties (water holding capacity (WHC), swelling capacity (SC), oil holding capacity (OHC) and emulsifying capacity (EC)). DFC dried at different temperatures showed interesting functional characteristics such as hydration properties, high OHC (2.73–4.60 g oil/g dry fibre) and EC (5.93–12.87%) values. Although drying temperatures promoted little modifications affecting the physicochemical properties of DFC, significant decreases in WHC, SC and EC of DFC were noticed at the highest temperature (60 °C) for most of the date varieties. The observed influence of drying temperature on functional DFC properties calls for the use of low temperature in order to obtain DFC as suitable food ingredient.     

Characterisation of alkaline and enzymatic modified insoluble dietary fibre from Undaria pinnatifida

Undaria pinnatifida insoluble dietary fibre (UIDF) was modified by alkali (NaOH solution) and complex enzyme (xylanase and cellulase) to improve the physicochemical properties. Scanning electron microscopy revealed that the surface structure after modification was rough and loose. The characteristic absorption peaks in Fourier transfer infrared spectrometry and X-ray diffraction patterns showed that enzymes can further hydrolyse the UIDF than alkali mainly in amorphous region, and increased the soluble dietary fibre content to 16.31%. The alkaline and complex enzymatic modification both resulted in higher water retention capacity, water swelling capacity, oil absorption capacity, glucose adsorption capacity and the inhibition ability towards α-amylase. The complex enzymatic modification exhibited better features in almost all properties, and the modification did not change the inhibiting mechanism on α-amylase (non-competitive type). Overall, both two modifications could effectively improve the properties of UIDF, which may promote its use in food applications.     

球磨处理对菠萝蜜果皮不溶性膳食纤维结构及性能的影响

为改善水不溶性膳食纤维（Insoluble dietary fiber,IDF）的口感和功能特性,以菠萝蜜果皮IDF为对象,采用行星球磨对其进行干法粉碎处理。通过表征分析及研究其理化性质的变化,探究不同球磨时间对菠萝蜜果皮IDF的微观形貌、化学结构、晶相结构和比表面积以及功能特性的影响。结果表明,球磨改性使IDF原有的纤维束状结构被破坏,粒径变小,比表面积增大,球磨时间18 h时,IDF的平均粒最小,比表面积最大,球磨改性不影响IDF的化学组成和结晶结构。随球磨时间延长,IDF的持水力、结合水力、溶胀性和阳离子交换能力呈先增大后减小的变化趋势,持油力总体呈下降趋势。球磨时间为18 h时,其持水力、结合水力最高,分别为4.6和4.3 g/g,阳离子交换能力也最强。研究表明球磨对菠萝蜜果皮IDF具有很好的粉碎改性效果并能改善其功能特性。     

Effects of micronization on the physico‐chemical properties of peels of three root and tuber crops

BACKGROUND: The aim of this study was to investigate the effect of micronization on the physicochemical properties of the peels of root and tuber crops, including yam (Dioscorea alata L.), taro (Colocasia esculenta L.) and sweet potato (Ipomea batatas L.). Two continuous milling sections, including hammer milling and ball milling, were applied to three samples to obtain micro‐sized particles of root and tuber peels. The micronization by ball‐milling treatment for 10 h was carried out to investigate the distribution of particle sizes and the changes in physiochemical properties. RESULTS: The results indicate that the peels of three crops appeared to be significantly decreased in particle size after 10 h of ball‐milling treatment. Moreover, the ball‐milling treatments resulted in the redistribution of fiber components from insoluble fiber to soluble fiber. The micronization treatments decreased the bulk density but increased the solubility and water‐holding capacities of the micronized peels. CONCLUSION: Our findings suggested that micronization treatments can improve functional properties of the fiber components of micronized peels, which provide a good source of dietary fiber in food applications. Copyright © 2010 Society of Chemical Industry     

Effects of Processing on the Compositions and Physicochemical Properties of Fibre Concentrate from Cooked Fruit Pomaces

This study examined the influence of applied technologies namely desugaring, grinding, and bleaching on the compositions (cellulose, hemicelluloses, lignins, and pectins), physicochemical properties (water-holding capacity (WHC), swelling capacity (SWC), oil-holding capacity (OHC)) and the colour of dietary fibre (DF) during the production of fibre concentrates from unusual cooked apple and pear pomaces. Thermogravimetric analysis (TGA) and optical microscopy were also performed to monitor process-induced modification. All the processing conditions affected the compositions and physicochemical properties of DF. The bleaching treatment induced the greatest changes on DF producing yellow cellulose-rich fibre concentrates with improved WHC from 3.2 to 10.0 g/g and improved SWC from 4.0 to 8.8 ml/g. Otherwise, reduction of the particle size influenced hydration properties and colours of DF. WHC and SWC tended to increase with the particle size whereas smaller granulometric size increased the lightness of fibres. Desugaring increased the DF content in both pomaces by 1.2-fold with slight modification of apple insoluble dietary fibre ratio. Fibre concentrates had improved WHC and SWC up to 1.4-fold. All processes had no significant effect (p?<?0.05) on OHC of DF except with ultrafine apple fibre concentrates. Results showed that processing had overall positive effects on DF contents and hydration properties of pomaces from cooked fruits. Bleached fibre concentrates from apple pomace had the highest WHC (10.0 g/g) whereas that of pear had the highest fibre content (89.9 %). Fibres from cooked fruit pomaces may therefore be used as textural ingredients or functional foods.     

Physicochemical and textural properties of dried squid as affected by alkaline treatments

The effect of alkaline treatment on the physicochemical and textural properties of dried squid was investigated. Dried squid soaked in 0.15 mol kg⁻¹ sodium carbonate with a squid/alkaline solution ratio of 1:10 (w/v) for 20 h was shown to be the most acceptable in terms of both appearance and textural properties. Sodium hydroxide appeared to extensively destroy the fibre structure, leading to a mushy texture of dried squid. Alkaline‐treated squid had increased moisture and ash contents but decreased shear force compared to dried squid. Alkaline treatment effectively disrupted various bonds stabilising the fibre structure, resulting in structural alteration and increased water absorption. Scanning electron microscopy (SEM) showed that alkaline treatment mainly contributed to swelling and disintegration of squid muscle fibre. As a result, dried squid acquired a softened texture with a higher water‐holding capacity. © 2000 Society of Chemical Industry     

Effects of fibre derived from passion fruit seed on the activities of ileum mucosal enzymes and colonic bacterial enzymes in hamsters

Passion fruit, a popular tropical fruit, produces a large quantity of edible seeds as agricultural byproducts after juice extraction. The defatted passion fruit seed (PFS) contained a high level of insoluble fibre (∼90%, w/w) of desirable characteristics and physicochemical properties. Cellulose, pectic substances and hemicellulose were the major structural polysaccharides of the PFS insoluble fibre. In this study, the influence of the PFS insoluble fibre on the activities of ileum mucosal enzymes and colonic bacterial enzymes was investigated. It was found that the incorporation of the PFS insoluble fibre into a fibre‐free diet at 5% level significantly (p < 0.05) enhanced the intestinal amylase activity (137%), reduced the caecal pH (6.22), decreased the caecal ammonia content (−38.6%) and faecal ammonia output (−21.2%), and also decreased the activities of β‐D ‐glucosidase (−37.4%), β‐D ‐glucuronidase (−52.9%), mucinase (−35.5%) and urease (−91.4%) in faeces. Our results suggested that PFS insoluble fibre might exert favourable effects on intestinal health. The fact that PFS insoluble fibre was more effective than cellulose in improving intestinal health suggested it could be exploited as a new functional ingredient to promote intestinal function and health. Copyright © 2005 Society of Chemical Industry