Amylase solution (5% w/v) was prepared by mixing 5 g of oCereals are often promoted as important sources of dietary fiber.amylase powder (Sigma A6880) for 15 min with 100 ml of buffer Ninety one breakfast cerealsavailable in Canada and four unprocessed solution pH 7 (61 ml O.lM Na$-IP04 + 39 ml O.lM NaI-$P04), wheat brans were therefore analyzed for neutral detergent fiber centrifuging 10 min at 3000 rpm and filtering through a coarse (NDF) after rapid digestion with o-amylase from porcine pancreas. sintered glass funnel. After refluxing .of the cereal sample with neutral detergent;the contents were filtered through a tared Gooch I Many breakfast-cereals contained less than 5% NDF:Wheat cereals contained 5-30% NDF, oat cereals contained 5% NDF, and corn ' crucible on the filtering manifold. (Goering and Van Soest, 1970) I and rice contained little NDF. Cereal NDF was predominantly and rinsed with hot distilled water. Next, 10 ml of o-amylase solutionhemicellulose (pentosans); pentose sugars liberated under hydrolysis and 40 ml of distilled water'at 70°C were added to the crucible,-giving a-mixture around 55'C. This was held for 5 mm on the represented up to 15% of processed bran cereals and 20-25% of unprocessed bran.filtering manifold and then suction was applied to the filter which .-was then washed with-hot distilled-water. The bottom of the crucible : was stoppered .(with 'a rubber stopper #8) and 10 ml of o-amylase

Samples of 15 food products and feces obtained by feeding them to rats were analysed for dietary fiber fractions. The food products were added as the sole source of protein in 8% protein diets, making up 8.8-51.6% of the diets. Diets were supplemented with 0.54-5.00% purified cellulose to make them more comparable in total fiber. Fiber analyses of food products revealed that the protein sources provided 0.06-7.27% total dietary fiber. The true protein digestibility in rats was negatively correlated with the total food fiber level (r = -0.69, P less than 0.01) or with the food cellulose level (r = -0.82, P less than 0.01) but it was positively correlated (r = +0.81, P less than 0.01) with the purified cellulose level. No relationship was found between protein digestibility and fiber fermentability. Results indicate that several food fiber fractions and possibly associated substances influenced protein digestibility. Purified cellulose did not have the same physiological behavior as food cellulose from the viewpoint of protein digestibility and fiber fermentability.

Total dietary fiber (TDF) was measured in 16 foods by three methods: a rapid enzyme-NDF (neutral detergent fiber) procedure supplemented with a separate procedure for soluble (SOL) fiber, the AOAC TDF method and the comprehensive Englyst's procedure. The NDF+ SOL method needed less operator time than the AOAC method and its TDF values were in agreement with the AOAC method (y = 0.98 X -0.39; r = 0.997) and with the Englyst's method (y = 1.17 X -0.19; r = 0.996). The constituent sugars of polysaccharides in NDF+ SOL residues were similar to those by the Englyst's method, indicating an adequate estimation of dietary fiber in foods and food products.

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