Insoluble Fiber Fractions Research Articles

Simplified fractionation process for linseed meal by alkaline extraction – Functional properties of protein and fibre fractions

A simplified linseed meal fractionation procedure for the extraction of protein and fibre has been developed. Response-surface methodology was used to investigate optimal parameters for linseed meal extraction. Based on the data of this extraction screening, the process technology was transferred to the pilot scale, obtaining a soluble protein and fibre containing fraction, and an insoluble fibre fraction. Water-binding and oil-binding capacities, protein solubility, emulsification capacity and foaming activity of the products were measured. The results indicated excellent functional properties of the two fractionation products, applicable especially to bakery products.

The influence of soluble and insoluble lupin non-starch polysaccharides on the digestibility of diets fed to rainbow trout ( Oncorhynchus mykiss)

This study examined the effect of increasing inclusion levels of soluble and insoluble lupin ( Lupinus angustifolius) fibres, and purified cellulose on the dry matter, protein and energy digestibility of diets fed to rainbow trout ( Oncorhynchus mykiss). Soluble and insoluble fibre fractions from lupin kernel meal were produced using differential pH solubilities. There were significant differences among the digestibility parameters of the diets with different inclusion levels of each of the different fibre types, except for the soluble lupin fibre, which had limited effect on any digestibility parameters. Differences among diets in dry matter and energy digestibility were most distinct. Using an ANOVA analysis no significant differences were noted for diet protein digestibilities with any of the fibre types. However, regression analysis of the effect of fibre inclusion levels showed significant effects on all digestibility parameters, including protein digestibilities. The lupin insoluble NSP also had a greater effect on dry matter and energy digestibilities than that of cellulose, with findings suggesting that it also affected the digestibility of additional nutrients in the diet to a degree not seen with cellulose. These results show that different fibre classes can have distinctly different effects on diet digestibility parameters.

Particle Size Reduction Effectively Enhances the Intestinal Health‐Promotion Ability of an Orange Insoluble Fiber in Hamsters

The effects of particle size changes by micronization on the intestinal health-promotion ability of orange insoluble fiber fraction (IFF) were investigated in a hamster model by feeding 3 diets, which contained unmicronized IFF (control), jet-milled IFF, and high-pressure micronized IFF as the sole fiber source in diet. The results showed that the micronization treatments significantly altered the physicochemical properties of insoluble fiber. The consumption of the micronized fibers (6.26 to 11.4 microm) at a level of 50 g/kg diet, especially those prepared by high-pressure micronization, resulted in significant (P < 0.05) improvements in cecal and fecal parameters such as reduced cecal ammonia concentration (-37.1%), increased fecal moisture (164%), and decreased activities of beta-D-glucuronidase (-68.3%) and mucinase (-28.5%) in feces. Both the particle size and treatment were important factors affecting the composition and physiological functions of fibers, and the consumption of micronized fiber might exert favorable effects on improving the intestinal health of hamsters. This study might give some hints for the potential applications of micron technology in food industry and provide opportunities to develop new formulations of fiber-rich functional foods.

Recovery of insoluble fibre fractions by filtration and centrifugation

Filtration and centrifugation methods were tested to study recovery of neutral and acid detergent fibre (NDF and ADF) and their N residues (NDFN and ADFN) in feeds, faeces and in vitro residues. Filtration of feeds and cow faeces were done in Porosity 2 (40–100 μm) sintered glass crucibles (SGC) or on flat papers (6 μm) or were centrifuged at 9000 × g for 5 min. Filtration of distillers dried grains with solubles and linseed cake by SGC clogged filters, unless sand was used as a filter aid. Fine feed fractions (<0.63 mm) gave relatively lower NDF recoveries by SGC filtration versus coarse fractions (0.63–1.5 mm). Centrifugation always resulted in higher recoveries of all the fibre fractions compared to SGC filtration. Paper filtration gave even higher recoveries for NDF and NDFN, compared to centrifugation. Digestibility of NDF in sheep gave lower estimates if feed and faecal NDF was estimated by paper filtration versus SGC filtration. The reason was a proportionally higher NDF recovery in faeces, as opposed to feed. Filtration on 6 μm papers should replace filtration in sintered glass crucibles to avoid serious losses of NDF, ADF and their respective N fractions.

Effects of high temperature on the growth and composition of sugarcane internodes

Sugarcane grown in the Ord River district of Western Australia has lower sucrose content than expected from earlier trials and experience in other irrigated districts. High temperatures have been hypothesised as a possible cause. The effects of high temperature (above 32°C) on growth and carbon partitioning were investigated. A temperature regime of (25–38°C) was compared with (23–33°C). In one experiment, 7-month-old plants of cvv. Q117 and Q158 were subjected to the treatments for 2 months. In another experiment, the plants were allowed to regrow (ratoon) for 6 months. In both experiments, the higher temperature resulted in more, shorter internodes and higher moisture content. Most internodes from plants in the higher temperature treatment had lower sucrose content than internodes from the lower temperature. On a dry mass basis the internodes from the plants in the higher temperature had proportionately more fibre and hexoses but lower sucrose. Combined with an increased number of nodes in a stem of similar or shorter length this would result in higher stalk fibre and lower sucrose content. The data provided evidence that sugarcane partitions less carbon to stored sucrose when grown under high compared with low temperatures. The two cultivars partitioned carbon between soluble (sugars) and insoluble (fibre) fractions to different degrees. These experiments also indicate that the current models describing leaf appearance and perhaps sugarcane growth at temperatures above 32°C, in general, need revision.

Dietary fiber consumption and composition of foods in “by‐the‐kilo” restaurants

PurposeIn Brazil, studies on dietary fiber consumption are scarce. The greatest difficulty is to obtain reliable data on the fiber content of foods that are part of Brazilians’ eating habits, which involves adjusting laboratory methodology. It is extremely important to evaluate the average daily fiber intake on a regional basis, considering the heterogeneous eating habits of the Brazilians. The study aims to estimate the average dietary fiber content of meals eaten in “by‐the‐kilo” restaurants.Design/methodology/approachThe foods used in the preparation of 1,907 meals consumed during one month in four restaurants in the city of São Paulo were studied. Intake, nutritional composition, and fiber analyses focusing on average lunch intakes were performed based on the RDA and SBAN (Brazilian Food and Nutrition Society) recommendations. Intake and nutritional composition results were compared with the values of a control meal theoretically prepared. A total of 40 samples of preparations using fiber‐rich foods were analyzed and their dietary fibers and soluble and insoluble fiber fractions were determined by enzymatic‐gravimetric method.FindingsThe results showed that a lunch meal alone accounts for 69.2 per cent of the SBAN recommendation and 39.5 per cent of the maximum RDA for dietary fiber.Originality/valueFoods served in “by‐the‐kilo” restaurants proved to be good sources of fiber, and their insoluble‐to‐soluble fiber ratios were similar to the recommendations.

Characterization of Dietary Fiber Lignins from Fruits and Vegetables Using the DFRC Method

Insoluble fiber fractions from 11 fruits and vegetables were investigated for their lignin composition using the derivatization followed by reductive cleavage (DFRC) methodology. To enrich lignin contents and to minimize polysaccharide excess that led to nonanalyzable DFRC chromatograms, the insoluble fibers were degraded by a carbohydrolases mixture. The residues that were found to be representative for the insoluble fiber lignins were analyzed. The investigated fibers differ considerably in their lignin contents and also in their lignin compositions. With the exception of radish fiber, only trace amounts (or none) of the products resulting from p-hydroxyphenyl units were detected. Lignins noticeably differed in the ratio of the DFRC products resulting from syringyl units (S) and guaiacyl (G) units (G/S ratios ranged from approximately 39 to 0.2). The insoluble fiber lignins were classified as G-rich lignins (G/S ratio > 3; carrot, spinach, kiwi, curly kale, radish, and asparagus), S-rich lignins (S/G ratio > 3; rhubarb), or balanced lignins (0.3 < G/S ratio < 3; pear, apple, small radish, and kohlrabi). Information about further structural characteristics, for example, cinnamyl endgroups, was obtained from the analysis of DFRC minor products.

Influence of insoluble fiber fractions from carambola and carrot on intestinal enzymes and fecal bacterial enzymes in hamsters

Juice production from carambola and carrot produces a large quantity of pomace. The pomace contains high levels of insoluble fiber fractions (IFFs) (50.8-56.3 g per 100 g of pomace, dry matter) that have desirable characteristics and physicochemical properties. In this study, the influence of IFFs derived from the pomace was investigated on the intestinal enzymes, fecal bacterial enzymes, and some biochemical parameters in the hamster. Our results showed that feeding carambola and carrot IFFs at 5% of the diet to hamsters significantly ( P < .05) reduced cecal pH (6.50-6.64), cecal and fecal ammonia levels (by 18.8%-21.2% and 50.0%-53.7%, respectively), and the activities of β- d-glucosidase (by 12.1%-20.1%), β- d-glucuronidase (by 54.8%-78.2%), mucinase (by 12.6%-20.2%), and urease (by 60.3%-63.7%) in feces. These results suggest that IFFs in carambola and carrot might exert favorable effects on improving intestinal functions and health and could be exploited as functional ingredients in fiber-rich food products.

EFFECT OF EXTRUSION COOKING AND SODIUM BICARBONATE ADDITION ON THE CARBOHYDRATE COMPOSITION OF BLACK BEAN FLOURS

Extrusion cooking and chemical leavening agents such as sodium bicarbonate (NaHCO3), may induce changes in carbohydrate fractions of extruded black bean (Phaseolus vulgaris L.) flours. Bean flours at 20% moisture, with NaHCO3 added at levels from 0.0 to 2.0%, were extruded at a screw speed of 200 rpm. The temperature profile ranged from 23 to 160C. Extruded bean flours with 0.1 to 0.4% added NaHCO3 were selected for sugar analyses based on color and flavor acceptability. The major sugars determined in the bean samples were galactose (0.10%), sucrose (2.08%), and stachyose (2.00%). Extruded samples had an increase in total sugars. Also, an increase in soluble fiber and a decrease of insoluble fiber fractions were observed. Sucrose was the only free sugar which concentration decreased consistently as a result of extrusion processing. Extrusion conditions and the selected levels of NaHCO3 used in this study did not significantly change the oligosaccharide content of the black bean flours.

Identification of gas‐producing components in different varieties of Phaseolus vulgaris by in vitro fermentation

AbstractPhaseolus vulgaris consumption has been limited as part of the occidental diet owing to flatulence production. Raffinose, stachyose and verbascose have been shown to be the main components responsible for flatulence; however, it is thought that soluble fibre could also be involved in this phenomenon. The aim of the present study was to identify the main components of beans influencing flatus. Ten varieties of P vulgaris originating from South America were first analysed for their main nutrient and carbohydrate fractions. Three of the varieties were then fractionated to extract soluble and insoluble fibres. Various combinations of α‐galactosides and soluble and insoluble fibre fractions, in similar proportions to those contained in cooked grains, were used as substrates for in vitro fermentation studies using human faecal inoculum to determine the fermentative capacity of each of the three fractions. Considering the white varieties, total gas production and acidification of the medium were correlated with fermented organic matter from soluble fibre (R2 = 1)) and with α‐galactosides (R2 = 0.75). On the other hand, tannins present in pigmented varieties did not seem to interfere significantly in fermentation of soluble fibre. The total production of gas per gram of mixed fractions of soluble fibre and α‐galactosides in proportions found in cooked grains was lower than that expected from each substrate separately. It can be concluded that soluble fibre and α‐galactosides are good substrates for endogenous colonic flora subjected to in vitro fermentation studies and are thus responsible for flatulence induced by legume consumption.© 2001 Society of Chemical Industry

Changes in Content and Composition of Dietary Fiber in Yellow Onions and Red Delicious Apples During Commercial Storage

Changes in pectin composition and solubility are part of the softening process in apples during ripening and postharvest storage. Lignification may also occur with long-term storage. In the United States, apples and onions are harvested once yearly and then stored and marketed for the next 12 months. The changes that occur in the dietary fiber content and composition in Red Delicious apples and yellow Spanish onions during storage were studied, and the loss of fiber in peeled apples was determined. Dietary fiber was extracted by the enzymatic-chemical method of Theander and Westerlund. Storage had no effect on total or insoluble fiber content of apples; Klason lignin concentration was greater in samples stored for 12 months than in those stored for 0, 4, or 8 months. Peeling reduced apple fiber concentration about 25% by decreasing neutral and acidic sugars and Klason lignin in the insoluble fraction. The total fiber content of onions increased with storage, primarily by increasing the insoluble fiber content of uronic acids. The results suggest that the standardized, environmentally controlled storage of apples, as used in Washington State, has little effect on dietary fiber content. In contrast, the less rigorously controlled storage conditions for yellow Spanish onions increases the insoluble fiber fraction and uronic acid content.

Dietary fibre content of thirteen apple cultivars

Fibre composition of the following 13 apple cultivars was studied: ‘Cortland’, ‘Empire’, ‘Fuji’, ‘Golden Delicious’, ‘Gala’, ‘Granny Smith’, ‘Jonagold’, ‘Mutsu’, ‘McIntosh’, ‘Delicious’, ‘Rome’, ‘Stayman’ and ‘York’. Fruit samples from each of these cultivars were analysed for non-starch cell wall materials (NSCWM) and non-starch polysaccharides (NSP). NSCWM was further fractionated into soluble and insoluble fibre fractions. Both NSCWM and NSP content were found to be significantly influenced by cultivar. NSCWM content ranged from 19·1 g kg−1 apple flesh in ‘Fuji’ to 36·2 g kg−1 in ‘York’. Mean(±SD) NSCWM content of all the cultivars was 23·1±4·5 g kg−1. NSP content of apple flesh ranged from 13·8 g kg−1 in ‘McIntosh’ to 28·7 g kg−1 in ‘York’ with the overall mean for all cultivars being 17·9±4·2 g kg−1. Relative amount of monosaccharides found in the hydrolysates of apple fibre also varied among cultivars. The greatest difference was observed in galactose content. ©1997 SCI

Dietary Fiber and Colorectal Cancer Risk

We conducted a population-based case-control study among different ethnic groups in Hawaii to evaluate the role of various types and components of fiber, as well as micronutrients and foods of plant origin, on the risk of colorectal cancer. We administered personal interviews to 698 male and 494 female Japanese, Caucasian, Filipino, Hawaiian, and Chinese cases diagnosed during 1987–1991 with adenocarcinoma of the colon or rectum and to 1,192 population controls matched to cases by age, sex, and ethnicity. We used conditional logistic regression to estimate odds ratios, adjusted for caloric intake and other covariates. We found a strong, dose-dependent, inverse association in both sexes with fiber intake measured as crude fiber, dietary fiber, or nonstarch polysaccharides. We found inverse associations of similar magnitude for the soluble and insoluble fiber fractions and for cellulose and noncellulosic polysaccharides. This protective effect of fiber was limited to fiber from vegetable sources, with an odds ratio of 0.6 (95% confidence interval = 0.4–0.9) and 0.5 (95% confidence interval = 0.3–0.7) for the highest compared with the lowest quartile of intake for men and women, respectively. We found associations of the same magnitude for soluble and insoluble vegetable fiber, but no clear association with fiber from fruits or cereals. This pattern was consistent between sexes, across segments of the large bowel (right colon, left colon, and rectum), and among most ethnic groups. The effect of vegetable fiber may be independent of the effects of other phytochemicals, since the effect estimates remained unchanged after further adjustment for other nutrients. Intakes of carotenoids, light green vegetables, yelloworange vegetables, broccoli, corn, carrots, bananas, garlic, and legumes (including soy products) were inversely associated with risk, even after adjustment for vegetable fiber. The data support a protective role of fiber from vegetables against colorectal cancer, which appears independent of its water solubility property and of the effects of other phytochemicals. The data also indicate that certain vegetables and fruits may be protective against this disease through mechanisms other than their fiber content.

Mineral binding capacity of dephytinized insoluble fiber from extruded wheat, oat and rice brans.

Insoluble fiber fractions from raw and extruded oat, rice and wheat brans were isolated and phytate removed. In vitro mineral binding studies were performed utilizing copper (Cu2+), calcium (Ca2+) and zinc (Zn2+) ions, which were added individually to enzymatically treated (Prosky et al., 1985), acid washed insoluble fiber residues from oat, rice and wheat brans. The enzymatic digestion step with alpha-amylase, protease and amyloglucosidase served to remove protein and starch from the samples. Mineral binding studies were performed on the insoluble fiber residue. Mineral content was determined by flame atomic absorption spectroscopy. Raw brans served as controls. A twin-screw extruder Model DNDG-62/20D, manufactured by Bühlerag (CH-9240, Uzwil, Switzerland) was utilized. The objectives of the study were to determine the total Cu2+, Ca2+ and Zn2+ binding capacity of the dephytinized insoluble fiber from each bran; and to determine if extrusion screw speed affected the brans' insoluble fiber mineral binding capacity. Although dephytinized, the brans' insoluble fiber fraction bound Cu2+, Ca2+ and Zn2+ ions. Oat bran bound more Cu2+, Ca2+ and Zn2+ than wheat bran, which bound more than rice bran. Extrusion processing did not affect the brans' insoluble fiber binding capacity to bind Cu2+. However, it increased the binding capacity of Ca2+ and Zn2+ of the insoluble fiber fraction from rice and oat brans.

Composición de la fibra alimentaria en el orujo de aceituna. Aminoácidos asociados a la fibra insoluble, soluble y total

Soluble sugars and dietary fibre were determined and the main components of the insoluble, soluble and total dietary fibre were analyzed. Aminoacids in both olive cake and fibre fractions were also studied. The results showed that olive cake fractions were also studied. The results showed that olive cake consists mainly of an alcohol insoluble residue that accounts for 77% of the dry matter (Klason lignin 37%, non-cellulosic polysaccharides 24%, cellulose 19% and protein 10%). Free sugars constitute 10% of the dry matter. Nearly 80% of all the amino acids in olive cake is associated with the insoluble dietary fibre fraction of these hydroxyproline and lysine are completely undigestible and methionine is the most available.

Properties of starch and dietary fibre in raw and processed quinoa (Chenopodium quinoa, Willd) seeds.

We investigated certain properties of starch in raw and in heat-treated samples of quinoa, properties that are of importance to the nutritional quality of an infant food currently being developed. Scanning electron microscopy of the starch in raw seeds showed polygonal granules (0.6 to 2.0 microns diameter) to be present both singly and as spherical aggregates. Thermograms (DSC) of the flours showed one transition phase for gelatinisation of the starch and another for the amylose-lipid complex. The gelatinisation temperature of the starch was 67 degrees C. Cooked samples manifested the highest degree of gelatinisation (97%), followed by the drum-dried (96%) and autoclaved (27%) samples. Separation of the starch on a SEPHAROSE CL-2B column showed the quinoa starch to be affected by the heat treatment, manifesting changes in the degree and extent of degradation. The amylograph viscosity of the quinoa flour showed no distinct peak for pasting, but the viscosity remained constant after gelatinisation. Cooking and autoclaving modified the viscosity of the paste. The drum-dried sample manifested a higher initial viscosity at 25 degrees C. The in vitro digestibility of raw quinoa starch determined by incubation for 60 min with alpha-amylase was 22%, while that of autoclaved, cooked and drum-dried samples was 32%, 45% and 73%, respectively. Saponins did not affect the digestibility of the starch, though they tended to increase the amylograph viscosity. The total dietary fibre content in the cooked sample (11.0%) was significantly lower than that in the autoclaved (13.2%), drum-dried (13.3%) or raw samples (13.3%), while the insoluble dietary fibre fraction in the samples did not change with heat treatment. However, as compared with that of raw quinoa, the soluble dietary fibre fraction was reduced significantly both by cooking (0.9%) and by autoclaving (1.0%).

Dietary fiber content and composition of different forms of fruits

The dietary fiber contents of 19 different forms of seven fruits were analyzed by two methods and compared. Fiber content measured by the AOAC method was always greater than that obtained by the Uppsala method; the two sets of fiber data were significantly different ( P < 0.002). Fiber contents of different forms of oranges, peaches and plums were similar. Fiber contents of four berries (blackberries, cranberries, red respberries, strawberries) ranged from 1.0 to 7.0% fresh weight. Peeling or canning changed the uronic acid and neutral sugar contents of the soluble and insoluble fiber fractions of several fruits. Measurement of more fiber in fruits by the AOAC versus the Uppsala method is similar to the results obtained when grain products and legumes, but not vegetables, were analyzed.

Comparison of Two Methods of Fiber Analysis of 58 Foods

Nine fruits, 8 grains, 9 legumes, 19 vegetables, 6 nuts and seeds, and 7 miscellaneous foods were analyzed for dietary fiber content using two methods of analysis. Fiber values determined using the AOAC method were either similar to or greater than those measured using the Uppsala method. The total fiber contents of the samples were generally similar to what have been reported for other foods in the same food group. Soluble fiber was an average of ∼15–20% of the total fiber in fruits, vegetables and grains, and <10% of total fiber in legumes, nuts, and seeds. Pectin and hemicelluloses were major soluble fiber components of fruits and vegetables. Grains contained little pectin. Glucose, representing cellulose, was usually the major (≥50%) neutral sugar in the insoluble fiber fractions of fruits, legumes, and vegetables. Neutral sugars in soluble fiber fractions suggested the presence of arabinogalactan hemicelluloses in fruits and vegetables. Arabinose and xylose were usually the major hemicellulosic sugars in grains. Within a food group the dietary fiber content and composition of the 58 foods were generally similar to those previously analyzed in the same food groups.

Enzymatic-Gravimetric Determination in Foods of Dietary Fiber as Sum of Insoluble and Soluble Fiber Fractions: Summary of Collaborative Study

A collaborative study was conducted on an enzymatic-gravimetric method for determination of total dietary fiber in foods, in which soluble fiber and insoluble fiber are determined separately. Ten collaborators analyzed blind duplicate test samples from 5 food products: turnip, wheat bran, beans canned with tomato sauce, rice, and whole wheat bread. Repeatability and reproducibility relative standard deviations ranged from 1.48 to 14.73% and from 4.13 to 17.94%, respectively. The method was adopted first action by AOAC International.

Batch and continuous anaerobic toxicity of resin acids from chemithermomechanical pulp wastewater

Chemithermomechanical pulp (CTMP) wastewaters are being treated anaerobically, in full scale operations, in spite of the presence of inhibitory compounds. These compounds are neither well identified nor are they placed in an order of priority in terms of inhibition to anaerobic bacteria. In this study batch anaerobic toxicity assays were used to quantify the relative toxicity of resin acids to the total toxicity in hydrogen peroxide bleached CTMP (BCTMP) wastewater. Resin acids are partitioned between the soluble wastewater and the insoluble fiber fractions. Therefore fiber toxicity was also compared to raw BCTMP wastewater toxicity. Resin acids were found to be toxic to anaerobic bacteria but were not found to be responsible for all the toxicity in BCTMP effluents. Toxicity associated with the fiber was soluble in methanol. The bulk of the fiber which was not methanol soluble exhibited no toxicity to the anaerobic cultures used. Batch results were compared to continuous toxicity assays using an upflow anaerobic sludge blanket reactor. The continuous reactor was relatively unaffected by short term or long term exposure to resin acids at concentrations that invoked inhibition in batch tests. Inferences from these tests indicated that batch results may be unreliable when applied to continuous systems.