Dietary fiber analysis

Saura-Calixto F, Garcia-Alonso A, Goni I and Bravo L. 2000. In vitro determination of the indigestible fraction in foods an alternative to dietary fiber analysis. J Agric Food Chem 48 3342-3347. 

The problems associated with the isolation and analysis of cell walls are (1) those arising from the preparation of cell wall material, (2) those associated with the isolation of wall components, (3) those associated with the fractionation of the carbohydrate polymers. There are also problems associated with the determination of the constituent sugars, their mode of occurrence, and fine structural details these are discussed later. The problems encountered in dietary fiber analysis and lignin determination, and measures for overcoming them, have been discussed at some length in a recent review (Selvendran and Du Pont, 1984) and will not be described in this chapter. 

A general procedure caimot always be applied for a particular component such as dietary fiber and vitamins. Special attention should be paid to these components a sample should be ground as finely as possible for dietary fiber analysis, and light and oxidation should be avoided for vitamin analyses. 

Schweizer TF (1989) Dietary fiber analysis. Lebensm Wiss Technol 22 45-59... 

BROWN L, ROSNER B, wiLLET w w, SACKS F M (1999) Cholesterol-loweiing effeects of dietary fiber a meta-analysis, American Journal of Clinical Nutrition, 69, 30-42. 

Nutrient analysis of stabilized rice bran and its derivatives indicates that it is a good source of protein, dietary fiber and carbohydrates, in addition to several valuable phytonutrients, antioxidants, vitamins and minerals (Table 17.1). SRB and its water-soluble and water-insoluble derivatives contain all the nutrients at different levels. They are gluten and lactose free and do not give rise to any food allergy. 

Brown, L., Rosner, B., Willett, W. W., and Sack, F. M. (1999). Cholesterol-lowering effects of dietary fiber A meta-analysis. Am. J. Clin. Nutr. 69, 30-42. 

Total dietary fiber (TDF) content of potato dry matter is determined according to the AACC (2000) method 32-05 following the total dietary fiber assay procedure (Megazyme k-TDFR 01/05). This is a gravimetric method that is simpler and faster than other analysis methods. In addition to total dietary fiber content, both soluble and insoluble dietary fiber content can be determined by this method. 

AOAC International. (1995). AOAC Method 991.43, Total, Insoluble and Soluble Dietary Fiber in Food—Enzymatic-Gravimetrie Method, MES-TRIS Buffer. Official Methods of Analysis, 16th ed., Gaithersburg, MD. 

Flours -infrared analysis of [INFRARED TECHNOLOGY AND RAMAN SPECTROSCOPY - INFRARED TECHNOLOGY] (Vol 14) -source of dietary fiber [DIETARY FIBER] (Vol 8) -soybean and other oilseeds [SOYBEANS AND OTHER OILSEEDS] (Vol 22)... 

Diets are isocaloric. The composition of the test and control (reference protein) diet (calculated on a dry weight basis) is 10% protein (1.6% nitrogen), 1 % AIN vitamin mix 76,3.5% AIN mineral mixture 76 (Nutritional Biochemicals), 0.2% choline bitartrate, 5% cellulose (only if test food is <5% total dietary fiber), corn oil to 10% total fat, and corn starch to total 100%. To account for differences in the protein content of the test diet, the level of corn starch can be adjusted (Joint FAO/WHO Expert Consultation, 1991). The chemical composition (proximate analysis) of the test protein must be measured before test diets are formulated. The proximate analysis of the test and control diets are to be measured after the diets are formulated, but before they are fed, to ensure that the protein content is the same for all diets, and that the diets are isocaloric. 

The preparation time for a PER is extensive and involves several days for acquisition of rats and their acclimation before a feeding trial begins. Preparation of a consistent and uniform diet is not trivial. Adequate diet for each treatment for the course of the study should be prepared shortly in advance of the study. Testing of the diet involves chemical analysis for protein (i.e., Kjeldahl N takes several hours) and accurate determination of other diet constituents (e.g., ash, crude lipid, and dietary fiber) so that isocaloric diets can be formulated between treatment groups. These determinations take >1 day to complete. It is recommended that multiple samples from each diet be obtained for proximate analysis of diet before it is fed to ensure that each diet has the proper nitrogen content (and this is same between diet treatments) and that all diets are isocaloric. 

Theander, O., and Westerlund, A., 1986, Studies on dietary fiber. 3. Improved analysis of dietary fiber, J. Agric. Food Chem. 34 330-336. 

Our first indication that fermentable fiber could alter microfloral metabolism was based on studies assessing the influence of dietary fiber types on the disposition of model xenobiotics using pharmacokinetic analysis (14). Amaranth was selected as a model xenobiotic for these studies because it was absorbed only after reduction by gut microflora (15). 

Schaller, D. (1977). Analysis of dietary fiber. Food Product Dev. 77 70-72. 

Schneeman, B. O. (1986). Dietary fiber physical and chemical properties, methods of analysis, and physiological effects. Food Technol. 40 104-110. 

Park, Y., Hunter, D.J., Spiegelman, D., et al., Dietary fiber intake and risk of colorectal cancer a pooled analysis of prospective cohort studies, JAMA, 294, 2849-2857, 2005. 

Tnock, B., Lanza, E., and Crcemvald, P, (1990). Dietary fiber, vegetabJes, and colon cancer Critical review and meta-analysis of the epidemiological evidence. /. Waff. Cancer hist. 82, 650-661. 

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