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Urea Enzymatic Dialysis Procedure for Determination of Total Dietary Fiber
Abstract
A method that uses urea and enzymes for determination of total dietary fiber (TDF) in foods has been developed and compared with the AOAC enzymatic-gravimetric method (43.A14-43.A20). In the evaluation, results for crude protein and ash contamination were higher by the AOAC method, particularly for samples that form gels during ethanol precipitation. The new urea enzymatic dialysis (UED) method quantitatively recovered, with less variation, more of the purified and semipurified dietary fiber products. TDF recoveries for carboxymethylcellulose and locust bean gum were 98% (SD 3.3) and 95% (SD 6.1) by the AOAC method and 99% (SD 1.0) and 100% (SD 0.6) by the UED method, respectively. The UED method was the more effective in removing starch. For kale samples, starch recovery was 3.5 and 0.2% from TDF residues obtained using the AOAC and UED methods, respectively. Differences were not significant among replicate values for determination of TDF in foods by the UED method (P greater than 0.01). Preliminary studies suggest that the new method can separately determine soluble and insoluble dietary fiber. The data indicate that the UED method is more precise and accurate than the AOAC method.
... This involved multiplying the total nitrogen content by 6.25 to calculate CP content. The neutral detergent fiber and acid detergent fiber in apple pomaces were analyzed by Van Soest's (1991) technique. Every chemical analysis was performed in duplicate. ...
This study focused on evaluating the nutritional characteristics and in vitro true digestibility of apple pomace derived from three apple cultivars: Golden Delicious, Starking, and Granny Smith (Malus domestica Borkh). These apple cultivars were sourced from the local market in Nigde, Turkiye. Statistical analyses, including one-way analysis of variance (ANOVA) and Duncan's test, were employed to assess variations among the apple pomace samples. Results indicated that, except for in vitro true digestibility, there were no significant variations in the chemical composition and total phenolic matter contents among the apple pomaces (P>0.05). However, Granny Smith apple pomace exhibited distinct features, such as higher neutral detergent fiber content (29.80%), elevated crude protein levels (5.09%) and substantial acid detergent fiber (25.30%) values. In contrast, Starking apple pomace displayed superior air-dry matter (27.24%), while Golden Delicious
showcased enhanced dry matter (95.3%) and ash content (2.00%). Regarding total phenolic matter contents, Granny Smith excelled with 112.4 mg GAE/100g, outperforming Starking (103 mgGAE/100g) and Golden Delicious (75.8 mg GAE/100g). Crucially, Starking demonstrated superior in vitro true digestibility, with values reaching 92.36% (as received) and 92.23% (dry matter).
Granny Smith, in comparison to Golden Delicious and Starking, displayed significantly different neutral detergent fiber digestibility (P<0.05). Starking apple pomace exhibit the highest overall digestibility among the apple pomaces analysed in this study, hence recommended for use in ruminant nutrition. These findings have implications for the potential utilization of apple pomace in diverse applications, given the diverse nutritional profiles of these cultivars.
... Ash was determined by burning the dried sample in oven at 550 0 c to 3 hours. The neural detergent fiber (NDF) was determined by the method of Van Soest et al. [13], while acid detergent fiber (ADF) and acid detergent lignin (ADL) were determined by the procedures of Van Soest et al. [14]. ...
... However, it does not provide a detailed profile of dietary fibre components. It was further modified by Jeraci et al. (1989), incorporating urea enzymatic dialysis to assure the removal of essentially all starch. Furthermore, during the same decade, Theander and Aman (1982) developed an indirect method to analyse total dietary fibre (TDF) in foodstuff by quantifying the amounts of uronic acids, sugars, klason lignin and starch and then calculating the total dietary fibre as the sum of the uronic acids, sugars and klason lignin minus the concentration of starch. ...
The use of some crops in Sub-Saharan Africa is currently limited to local culinary uses despite promising characteristics of their non-starch polysaccharide. There is very little information on the properties of their non-starch polysaccharide which would stimulate expansion in their applications. Non-starch polysaccharides represent a group of heterogeneous compounds which differ considerably in chemical composition and physical properties both within and between plant sources. They show various physiological effects in the small and large intestine and therefore have important health implications for humans. The physiochemical and biological properties of these compounds correspond to dietary fibre. Their application/introduction in food may lead to diminished risk of serious diet-related diseases which are major problems in Western countries and are emerging in developing countries with a greater affluence. Insoluble NSPs (cellulose and hemicellulose) are effective laxatives whereas soluble NSPs (especially mixed-link β-glucans) lower plasma cholesterol levels and help to normalise blood glucose and insulin levels, making these kinds of polysaccharides a part of dietary plans to treat cardiovascular diseases and type 2 diabetes. In this review, techniques applied in characterising non-starch polysaccharides in five underutilised crops in sub-Saharan Africa were discussed.
... Because of these problems, the method was modified, including dialysis with urea, which avoids the heat treatment and removes byproducts by dialysis. The principle of the method consists in the special activity of thermostable enzyme in 8M urea solution [36]. Asp [37] developed a method for the analysis and characterization of food polysaccharides factions, which was adapted for feed by Southgate [38] and Bach Knudsen [39]. ...
Polysaccharides are macromolecules of monosaccharides linked by glycosidic bonds. Non-starch polysaccharides (NSP) are principally non-α-glucan polysaccharides of the plant cell wall. They are a heterogeneous group of polysaccharides with varying degrees of water solubility, size, and structure. The water insoluble fiber fraction include cellulose, galactomannans, xylans, xyloglucans, and lignin, while the water-soluble fibers are the pectins, arabinogalactans, arabinoxylans, and β-(1,3)(1,4)-D-glucans (β-glucans). Both the enzymatic-gravimetric and enzymatic-chemical methods used for the determination of soluble and insoluble non-starch polysaccharides have undergone a number of modifications and improvements, most occurring over the last 20 years.
... Starch ribbons containing high levels of urea were stiff because of the low mobility of urea compared with ribbons containing high levels of glycols. This result is due to the higher mobility or fluidity of glycols [67,68,71,72,[97][98][99][100][101][102][103]. ...
Thermoplastic starch (TPS) polymers were reviewed in this article. This review was categorized into the following studies: the role of starch as a thermoplastic polymer, transformation and melting mechanisms, plasticization and plasticizers, reactive extrusion (REX) and modifications, retrogradation, biodegradability, filler and blenders, and nano-particle incorporation in thermoplastic starch. This categorization allows us to understand the developments in this field in recent years and shows that the major challenges in the future are reducing sensitivity to moisture and retarding retrogradation of the thermoplastic matrix. Moreover, nano-particles such as clay can be used in TPS matrices to overcome these disadvantages.
... Asp, Johansson, Hallmer, and Siljeström (1983) developed an enzyme-based gravimetric method, in which a sample is pretreated with enzymes for the digestion of starch and protein, followed by the recovery of soluble components via precipitation in ethanol and the insoluble components by filtration. This method was further modified by Jeraci, Lewis, Van Soest, and Robertson (1989), incorporating a urea enzymatic dialysis to assure the (2001); Leenhouwers et al. (2006) Alteration in the native gut microflora Stimulated microbial fermentation in intestine. Enhanced volatile fatty acids, such as acetic acid, propionic and butyric acids, production Lower pH of intestinal tract; in long term may disturb the normal micrbiota prevailing in gut Influenced bioavailability of dietary minerals Decreased oxygen tension, favouring development of anaerobic microbiota Wood and Serfaty-Lacrosniere (1992); Choct (1997); Amirkolaie et al. (2006); Leenhouwers et al. (2007aLeenhouwers et al. ( , 2007b Alteration in gut mucus layer ...
The success and sustainability of aquaculture depends on minimising the operational cost of feed that in general comprises 50–60% of the total cost in intensive farming. The major feed ingredient, fish meal, is expensive and there is increasing competition with other livestock industries for the available static supply of fish meal. Hence, the incorporation of plant-derived materials in fish feeds is receiving increasing attention. One of the main constraints in the utilisation of plant ingredients in aquaculture is the presence of indigestible carbohydrates, which consist primarily of non-starch polysaccharides (NSPs). These form a part of the cell wall structure of cereals and legumes. The presence of NSPs in the diet interferes with feed utilisation and adversely affects performance of the animal. Supplementation of NSP-degrading enzymes in feed mitigates the adverse effects of NSPs. The effects of NSPs in pigs and poultry have been widely studied; however little information exists for fish. This review synthesizes the available information on fish and highlights the knowledge gaps. It is hoped that this review will provide a momentum to the research on the roles of NSPs in fish nutrition and physiology and on the efficient use of NSP-degrading enzymes.
... Asp, Johansson, Hallmer, and Siljeström (1983) developed an enzyme-based gravimetric method, in which a sample is pretreated with enzymes for the digestion of starch and protein, followed by the recovery of soluble components via precipitation in ethanol and the insoluble components by filtration. This method was further modified by Jeraci, Lewis, Van Soest, and Robertson (1989), incorporating a urea enzymatic dialysis to assure the (2001); Leenhouwers et al. (2006) Alteration in the native gut microflora Stimulated microbial fermentation in intestine. Enhanced volatile fatty acids, such as acetic acid, propionic and butyric acids, production Lower pH of intestinal tract; in long term may disturb the normal micrbiota prevailing in gut Influenced bioavailability of dietary minerals Decreased oxygen tension, favouring development of anaerobic microbiota Wood and Serfaty-Lacrosniere (1992); Choct (1997); Amirkolaie et al. (2006); Leenhouwers et al. (2007aLeenhouwers et al. ( , 2007b Alteration in gut mucus layer ...
The success and sustainability of aquaculture depends on minimising the operational cost of feed that in general comprises 50–60% of the total cost in intensive farming. The major feed ingredient, fish meal, is expensive and there is increasing competition with other livestock industries for the available static supply of fish meal. Hence, the incorporation of plant-derived materials in fish feeds is receiving increasing attention. One of the main constraints in the utilisation of plant ingredients in aquaculture is the presence of indigestible carbohydrates, which consist primarily of non-starch polysaccharides (NSPs). These form a part of the cell wall structure of cereals and legumes. The presence of NSPs in the diet interferes with feed utilisation and adversely affects performance of the animal. Supplementation of NSP-degrading enzymes in feed mitigates the adverse effects of NSPs. The effects of NSPs in pigs and poultry have been widely studied; however little information exists for fish. This review synthesizes the available information on fish and highlights the knowledge gaps. It is hoped that this review will provide a momentum to the research on the roles of NSPs in fish nutrition and physiology and on the efficient use of NSP-degrading enzymes.
... Later, Asp et al. (1983) developed an enzymae based gravimetric method in which a sample is pretreated with enzymes for the digestion of starch and protein, followed by the recovery of soluble components via precipitation in ethanol and the insoluble components by filtration. This method was further modified by Jeraci et al. (1989), incorporating a urea enzymatic dialysis to assure the removal of essentially all starch. Moreover, during the same decade Theander and Aman (1982) developed an indirect method to analyze total dietary fiber (TDF) in foodstuff by quantifying the amounts of uronic acids, sugars, klason lignin, and starch and then calculating the TDF as the sum of the uronic acids, sugars, and klason lignin minus the concentration of starch. ...
Nonstarch polysaccharides (NSPs) occur naturally in many foods. The physiochemical and biological properties of these compounds correspond to dietary fiber. Nonstarch polysaccharides show various physiological effects in the small and large intestine and therefore have important health implications for humans. The remarkable properties of dietary NSPs are water dispersibility, viscosity effect, bulk, and fermentibility into short chain fatty acids (SCFAs). These features may lead to diminished risk of serious diet related diseases which are major problems in Western countries and are emerging in developing countries with greater affluence. These conditions include coronary heart disease, colo-rectal cancer, inflammatory bowel disease, breast cancer, tumor formation, mineral related abnormalities, and disordered laxation. Insoluble NSPs (cellulose and hemicellulose) are effective laxatives whereas soluble NSPs (especially mixed-link β-glucans) lower plasma cholesterol levels and help to normalize blood glucose and insulin levels, making these kinds of polysaccharides a part of dietary plans to treat cardiovascular diseases and Type 2 diabetes. Moreover, a major proportion of dietary NSPs escapes the small intestine nearly intact, and is fermented into SCFAs by commensal microflora present in the colon and cecum and promotes normal laxation. Short chain fatty acids have a number of health promoting effects and are particularly effective in promoting large bowel function. Certain NSPs through their fermented products may promote the growth of specific beneficial colonic bacteria which offer a prebiotic effect. Various modes of action of NSPs as therapeutic agent have been proposed in the present review. In addition, NSPs based films and coatings for packaging and wrapping are of commercial interest because they are compatible with several types of food products. However, much of the physiological and nutritional impact of NSPs and the mechanism involved is not fully understood and even the recommendation on the dose of different dietary NSPs intake among different age groups needs to be studied.
... Later, Asp et al. (1983) developed an enzymae based gravimetric method in which a sample is pretreated with enzymes for the digestion of starch and protein, followed by the recovery of soluble components via precipitation in ethanol and the insoluble components by filtration . This method was further modified by Jeraci et al. (1989), incorporating a urea enzymatic dialysis to assure the removal of essentially all starch. Moreover, during the same decade Theander and Aman (1982) developed an indirect method to analyze total dietary fiber (TDF) in foodstuff by quantifying the amounts of uronic acids, sugars, klason lignin, and starch and then calculating the TDF as the sum of the uronic acids, sugars, and klason lignin minus the concentration of starch. ...
... Asp, Johansson, Hallmer, and Siljeström (1983) developed an enzyme-based gravimetric method, in which a sample is pretreated with enzymes for the digestion of starch and protein, followed by the recovery of soluble components via precipitation in ethanol and the insoluble components by filtration. This method was further modified by Jeraci, Lewis, Van Soest, and Robertson (1989), incorporating a urea enzymatic dialysis to assure the (2001); Leenhouwers et al. (2006) Alteration in the native gut microflora Stimulated microbial fermentation in intestine. Enhanced volatile fatty acids, such as acetic acid, propionic and butyric acids, production Lower pH of intestinal tract; in long term may disturb the normal micrbiota prevailing in gut Influenced bioavailability of dietary minerals Decreased oxygen tension, favouring development of anaerobic microbiota Wood and Serfaty-Lacrosniere (1992); Choct (1997); Amirkolaie et al. (2006); Leenhouwers et al. (2007aLeenhouwers et al. ( , 2007b Alteration in gut mucus layer ...
The study aimed to evaluate the nutritional composition and in – vitro true digestibility
of apple pomaces obtained from three apple (Malus domestica Borkh.) cultivars -
Golden delicious, Starking and Granny Smith. The apple pomace samples were not
significantly different in terms of the parameters measured (P>0.05) for chemical
analysis and total phenolics content (TPC) except for in-vitro true digestibility.
However, Starking pomace sample (SPS) had higher ADM 27.24%, Golden delicious
pomace sample (GdPS) had higher DM 95.3% and Ash 2.00% values while Granny
smith pomace sample (GsPS) had the higher NDF value 29.80%, CP 5.09 and ADF
25.30% respectively. GsPS have the highest TPC 112.4 mg GAE/100g compared to
SPS 103 mg GAE/100g and GdPS 75.8 mg GAE/100g. SPS had higher IVTD (as fed)
92.36% and IVTD (DM) 92.23%. GsPS had significantly different (p < 0.05) NDFD
from GdPS and SPS. Based on the result apple pomace can serve as an important
component of ruminant ration.
Whichever definition is used for dietary fibre the major components are polysaccharides and the classification of these carbohydrates in foods provides the background for the analytical strategies.
Dietary fibres (DF), composed of celluloses, hemicelluloses, pectins, lignins and other non-digestible materials In the food not amenable to the action of alimentary enzymes of human beings, play a multifaceted role in preventing a number of health disorders through their Influence in the gastrointestinal tract. Their effectiveness is governed by physical properties such as particle size when ingested, water holding capacity, solubility and viscosity in aqueous phase, affinity to bile acid salts, cationic binding/exchange effect, fermentability in the bowel and chemical Identity and proportion of the various constituents. DF undergo very little changes during processing of foods except size reduction. Estimation of DF is carried out by detergent treatments and/or enzyme digestions followed by gravi-metric and/or colorimetric and/or GLC techniques. Inadequate level of DF in the diet has been implicated in many human diseases like coronary heart disease, blood pressure, obesity, hypercholesterolemia, hyperlipidemia, gall stones, varicose veins, diabetes, constipation and diverticulitis. A per capita daily intake of 30g of DF or 12g of DF/1000 kCal per day is considered desirable, to be obtained from as varied sources as possible with about one-third being soluble fibre. While cereal sources provide a major part of insoluble DF, fruits, vegetables, oats, plant gums and mucilages, seaweed and microbial polysaccharides are important sources of soluble DF. Fibre concentrates containing up to 100% DF are commercially available for enrichment of food preparations and development of high fibre processed food products. Non-starch polysaccharides extracted from plant, seaweed and microbial sources, their modified derivatives and synthetic oligosaccharides are increasingly being used by the food processing industry as food adjuncts for specific functional effects such as fat replacement, textural management and lowering of caloric content of foods. While use of various DF preparations are generally considered safe for human consumption, further studies may be necessary, at least in some cases, to confirm their absolute safety for long term use and at high concentrations. Many aspects of functions of DF in human body are still not clearly understood and this is considered to be an emerging area deserving increased attention from polysaccharide chemists, food scientists, nutritionists, clinicians and technologists in the coming years.
RESUMO. Foram avaliados os atributos de precisão e o uso do método enzímico-gravimétrico descrito por Prosky et al. (1992) (AOAC, 985.29) para a determinação de fibra alimentar em grãos de cereais, utilizando-se milho (BR 5202 Pampa) e aveia (UFRGS 15). Para determinar o efeito de corridas laboratoriais executadas em diferentes dias, organizou-se seis corridas para cada amostra, cada qual formada por uma duplicata para a determinação de fibra total (FT), uma para fibra insolúvel (FI) e provas em branco, também em duplicata, para FT e FI. A fim de caracterizar a repetibilidade, outras cinco determinações de FT e FI foram realizadas para cada uma das amostras, totalizando 11 dados. Os coeficientes de variação de FT e FI obtidos nas 6 primeiras corridas foram baixos, indicando uma variação intralaboratorial total aceitável. Os CVs (
An increase in dietary fiber consumption has been recommended by the public health authorities. In this review the definition of dietary fiber and analytical methods used for its measurement are discussed. Furthermore, effects of processing on dietary fiber—especially the formation of resistant starch, the role of dietary fiber in health and disease, and intakes in different countries—are discussed.
The ethanol precipitation of soluble dietary fibre (SDF) constituents is a common step among modern analytical methods.This precipitation may involve two possible error sources: non-fibre component co-precipitation and incomplete precipitation of SDF components such as pectins. Both possibilities are studied in the present work.Citrus pectins and pectin-organic acid (citric and oxalic) mixtures were dissolved in phosphate buffer and precipitated in 78% ethanol at different pH values. Incomplete recovery of pectins (84–89%, depending upon the pH of the solution) and significant co-precipitation of organic acids were observed.Dialysis has been studied as an alternative method for obtaining SDF. Both dialysis and precipitation techniques were carried out to determine SDF in fruits, legumes and cereals. The SDF values (neutral sugars plus uronic acids) obtained by dialysis were higher in all the samples than the values obtained by precipitation.These results show the incomplete determination of SDF with the present analytical methods. In addition, gravimetric methods can include a fraction of non-fibre constituents, such as organic acids, as fibre.
This review describes methods for cell wall measurement which have been or are the most useful for ruminant feeding. The methods have been classified into three main categories: direct or gravimetric methods, fractionation methods into separate constituents and physico-chemical methods. The chemical basis and the nutritive information are presented for these three groups of methods.This review emphasizes the relative advantages of the different methods and the factors to be kept in mind when choosing the most appropriate method for a definite goal. Indeed, it seems that when feeds are from varied or unknown origins, analytical schemes including lignin determinations are the most suitable for a routine analysis in order to determine their nutritive value. When analysing feeds from the same botanical family, a physico-chemical method like the near infrared spectroscopy is probably the best method, especially when there is a large number of samples.
The nutritional effects of flaxseed (Linum usitatissimum, variety Linott) were studied in the rat. In addition, thermal and storage stabilities of flaxseed were evaluated. Weanling rats were fed diets containing ground flaxseed at levels of 0, 10, 20, or 40% for 90 days. No differences were found in the food intake nor in body and organ weights. Serum triglyceride, total cholesterol, and the low-density lipoprotein (LDL) cholesterol concentrations were significantly lower in the rats fed the 20% and 40% flaxseed diets compared to the 0% flaxseed group. The high-density lipoprotein (HDL) cholesterol concentration and the LDL:HDL-cholesterol ratio were generally lower in the flaxseed-fed rats when compared to the 0% flaxseed group, but a significant lowering occurred only in the 40% flaxseed group. The incorporation of flaxseed in the diet caused significant elevations in the levels of the α-linolenic acid in adipose tissue and in organs. Higher amounts of eicosapentaenoic, docosapentaenoic, and docosahexaenoic acids were observed in the heart and liver of flaxseed-fed rats when compared to the 0% flaxseed group. A significant lowering of tissue vitamin E levels and an elevation of urinary thiobarbituric reacting substances occurred only in the 40% flaxseed group, which suggested that low to moderate intakes of flaxseed did not impart an oxidative stress on rat tissues. Dietary fiber in flaxseed appeared to be largely fermentable and was associated with a large increase in fecal moisture. The phytate in flaxseed had no effect on zinc status. The oil in both the intact and the ground flaxseeds was found to be thermally and oxidatively stable.
The soluble and insoluble dietary fibre contents of seven marine algae (‘sea vegetables’): wakame (Undaria pinnatifida), hijiki (Hijiki fusiformis), sea spaghetti (Himanthalia elongata), arame (Eisenia bicyclis), sea lettuce (Ulva lactuca), A O nori (Enteromorpha spp), and nori (Porphyra tenera) were determined by the gravimetric method of Prosky et al (J Assoc Anal Chem 1988, 71 1017–1023) following some adaptations. These seaweeds are particularly rich in dietary fibres with total dietary fibre contents varying between 32·7 and 74·6% (on a dry weight basis) of which 51·6 to 85·0% are water soluble. Marine algae appear to be good sources of fibres presenting great chemical, physico-chemical and rheological diversities that may be beneficial in nutrition.
Dietary fiber is a complex mixture of nondigestible polysaccharides and lignin, the exact composition depends on the plant or other food source, maturity, growing conditions, and processing. Plant cell wall polysaccharides are extensively fermented by the microbial enzymes in the lower digestive tract. The particle size and shape, density, crystallinity, water-holding capacity, and the level and type of dietary fiber affect the rate of passage of the digests through the digestive tract. Dietary fiber itself and the microbial fermentation in the colon give rise to various beneficial physiological effects. Dietary sources of soluble and insoluble fiber and their properties and methods for analysis are summarized. Specific food sources of dietary fiber are given. Fiber supplements are discussed.
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.
There is a need to standardize the NDF procedure. Procedures have varied because of the use of different amylases in attempts to remove starch interference. The original Bacillus subtilis enzyme Type IIIA (XIA) no longer is available and has been replaced by a less effective enzyme. For fiber work, a new enzyme has received AOAC approval and is rapidly displacing other amylases in analytical work. This enzyme is available from Sigma (Number A3306; Sigma Chemical Co., St. Louis, MO). The original publications for NDF and ADF (43, 53) and the Agricultural Handbook 379 (14) are obsolete and of historical interest only. Up to date procedures should be followed. Triethylene glycol has replaced 2-ethoxyethanol because of reported toxicity. Considerable development in regard to fiber methods has occurred over the past 5 yr because of a redefinition of dietary fiber for man and monogastric animals that includes lignin and all polysaccharides resistant to mammalian digestive enzymes. In addition to NDF, new improved methods for total dietary fiber and nonstarch polysaccharides including pectin and beta-glucans now are available. The latter are also of interest in rumen fermentation. Unlike starch, their fermentations are like that of cellulose but faster and yield no lactic acid. Physical and biological properties of carbohydrate fractions are more important than their intrinsic composition.
Dietary guidelines encourage a considerable increase in carbohydrate intake compared with the present situation in Western countries. Recent developments regarding nutritional effects of various digestible and undigestible carbohydrates call for more detailed recommendations. The "carbohydrates by difference" concept emerged 150 y ago because of the lack of specific analytical techniques and still prevails. The concept of available compared with unavailable carbohydrate was introduced in 1929 to obtain a better measure of glucogenic carbohydrates in diabetes. Dietary fiber was first defined as the "skeletal remnants of plant cell walls," but the definition was later expanded to include all polysaccharides and lignin that are not digested in the small intestine. The gravimetric method of the Association of Official Analytical Chemists for total dietary fiber is based on this undigestibility concept. However, precipitation of soluble fiber components with alcohol, which is used in all current methods, creates an arbitrary delimitation between oligo- and polysaccharides. The complex carbohydrates concept is challenged by recent developments regarding nutritional effects of various food carbohydrates.
The precision attributes and use of the enzymatic-gravimetric method of Prosky et al. (1992) (AOAC 985.29) were evaluated using corn (BR 5202 Pampa) and oat (UFRGS 15) samples. The effect of laboratory batches carried out in different days were evaluated in six laboratory batches, using for each material one duplicate for total fiber (FT) determination, one duplicate for insoluble fiber (FI) determination and blank ones for FT and for FI (both in duplicate). In order to characterize repetitive aspects, five other FT and FI determinations added to each sample were evaluated, summing up 11 data. The low coefficients of variation in the first six batches were considered acceptable as an expression of expected total intralaboratory variation. The repetitive of the method was considered good for FT determinations (CVs < 10%). However, in the FI determination a high frequency of negative values of ash and blanks was found, impairing the repetitive aspects evaluation. The magnitude of the total gravimetric corrections varies with the kind of the sample and is especially influenced by the protein content.
- L Prosky
- N.-G Asp
- I Furda
- J W Devries
- T F Schweizer
- B F Harland
Prosky, L., Asp, N.-G., Furda I., DeVries, J. W., Schweizer, T.
F., & Harland, B. F. (1985) /. Assoc. Off. Anal. Chem. 68,
677-679
- L Prosky
- Asp
- N.-G
- I Furda
- J W Devries
- T F Schweizer
- B F Harland
Prosky, L., Asp., N.-G., Furda, I., DeVries, J. W., Schweizer,
T. F., & Harland, B. F. (1984) J. Assoc. Off Anal. Chem. 67,
1044-1052
- P J Van Soest
- R W Mcqueen
Van Soest, P. J., & McQueen, R. W. (1973) Proc. Nutr. Soc.
32, 123-130
- A Grace
- D T Gordon
Grace A., & Gordon, D. T. (1986) Am. Assoc. Cereal Chem.
(AACC), Toronto, Canada
Forage Fiber Analysis, Agriculture Handbook No. 379
- H K Goering
- P J Van Soest
Goering, H. K., & Van Soest, P. J. (1970) Forage Fiber
Analysis, Agriculture Handbook No. 379, U.S. Department of
Agriculture, Washington, DC
- N Blumencrantz
- G Asboe-Hansen
Blumencrantz, N., & Asboe-Hansen, G. (1973) Anal. Biochem. 54, 484-489
XlVth International Carbohydrate Symposium
- S Glatter
- J Carr
- B A Lewis
Glatter, S., Carr, J., & Lewis, B. A. (1988) XlVth International Carbohydrate Symposium, Stockholm, Sweden, Aug. 14-19
Symposium on Cereal Carbohydrates
- J Carr
- S Glatter
- B A Lewis
Carr J., Glatter, S., & Lewis, B. A. (1988) Symposium on
Cereal Carbohydrates, Edinburgh, Scotland, Aug. 9-11
- H N Englyst
- J H Cummings
Englyst, H. N., & Cummings, J. H. (1986) Am. J. Clin. Nutr.
44, 42-50
- A C Jennings
- W B Watt
Jennings, A. C, & Watt, W. B. (1967) /. Sci. Food Agric. 18,
527-535
- P J Van Soest
Van Soest, P. J. (1982) in Nutritional Ecology of the Ruminant, O&B Books, Comstock Publ. Assoc, Ithaca, NY