A rapid enzymic method for starch analysis, especially in cereal products, is presented. One person can analyze 30 samples per day. The method includes a 15 min gelatinization step in a boiling water bath in the presence of a thermostable α‐amylase, a 30 min amyloglucosidase incubation of a subsample, and subsequent determination of glucose with a glucose oxidase/peroxidase reagent. The method was evaluated by analysis of the starch content in various raw and industrially processed wheat samples. The method showed high precision (CV=0.6–1.0%) and accuracy. Some factors which might affect the enzymic availability of starch and thus its recovery in the analysis are evaluated and discussed.

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Postprandial glycemic and insulinemic responses and satiety with various barley products were evaluated in normal subjects. Also studied were the rate of in vitro starch digestion and the content of in vitro resistant starch (RS). Products tested were boiled intact (rice extender) and milled kernels (porridge) from four barley genotypes of Glacier with different amylose-amylopectin ratios (7-44% amylose). All barley products elicited lower metabolic responses and higher satiety scores when compared with white wheat bread. The lente behavior of the boiled flours was probably due to the viscous properties of the beta-glucans. However, the boiled flours produced higher glucose and insulin responses than did the corresponding boiled kernels. The impact of amylose: amylopectin on the metabolic responses was marginal. The high-amylose products released starch more slowly from a dialysis tubing during enzymic incubation of chewed samples compared with the corresponding products with less amylose. The RS content ranged from 0.4% in waxy to 5.6% in the high-amylose flour product (starch basis).

The purpose of this work was to develop a method for measurement of the major forms of resistant starch (RS) in foods. The analytical procedure was chosen to mimic physiologic conditions, and included chewing as a prestep before incubation with pepsin, pancreatin and amyloglucosidase. The undigestible polysaccharides, including RS, were recovered by ethanol precipitation and subsequent filtration. RS was analyzed as total starch in the filter residue. The residues were also used for gravimetric determination of dietary fiber after correcting for remaining protein, ash and RS. The potentially available starch fraction was determined from analysis of glucose in the filtrate. The foods included were prepared to resemble products for which RS figures were available from in vivo measurements, and/or from analysis with other current in vitro methods. For six of these foods, and for three additional starchy materials, RS figures were compared with in vivo and/or in vitro data for identical products. The pooled standard deviation for the suggested RS method was 2.9%. A high correlation was obtained with in vivo figures from the literature for 19 realistic foods (r = 0.97; y = 0.77x + 0.45). After correction for RS, dietary fiber figures corresponded well with conventional gravimetric dietary fiber analysis for 14 starchy foods (r = 0.97). It is concluded that the procedure described here provides a convenient way to estimate RS content of realistic foods, allowing parallel determination of the potentially available starch fraction and dietary fiber.

The purpose of the present investigation was to study the importance of the amylose/amylopectin ratio for the content and gastrointestinal fate of resistant starch in a realistic composite starchy food. Corn-based breads (arepas) from dent corn (25% amylose) and from high amylose corn (70% amylose) were used as test products. Resistant starch concentration was evaluated in vitro and in vivo using rats treated with an antibiotic drug (Nebacitin) to suppress hindgut fermentation. Experiments in rats with intact hindgut microflora allowed determination of resistant starch fermentability. The small intestinal digestibility of starch in dent corn arepas was close to 96% (total starch basis), whereas the starch in high amylose arepas was poorly digested (approximately 68%, total starch basis), as calculated from the fecal recovery of resistant starch in Nebacitin-treated animals. The main resistant starch fraction required solubilization in alkali to render it available to the analytical amylases (nonhydrated fraction). The total amount of resistant starch as well as the nonhydrated starch fraction delivered to the hindgut could be accurately predicted from analysis of starch remnants in an enzymatic gravimetric dietary fiber residue. Resistant starch present in dent corn arepas was fermented approximately 63%, whereas the fermentability of resistant starch from the high amylose product was remarkably low (< 11%).

Abstract— The aim was to evaluate chemically modified starches (CMS) from a cariologic point of view as alternatives to gum arabic in sugar‐free lozenges. Two commercial CMS, Purity Gum 40 and Capsul, were selected due to their comparatively low availability to alpha‐amylase in vitro. Both gelatinized CMS suspensions and lozenges were tested in vivo by measuring plaque pH. The results showed that suspensions of Purity Gum 40 or Capsul were less available to alpha‐amylase in vitro than the soluble starch reference. However, the initial phase of amylolysis was comparatively rapid also with CMS. In spite of the slower rate of hydrolysis, suspensions of the two CMS reduced pH of dental plaque in vivo to the same extent as soluble starch, but somewhat less compared with glucose. Lozenges with Purity Gum 40 also lowered plaque pH, although less than when administered as a precooked suspension. The most prominent pH drop was found with a lozenge containing Purity Gum 40‐sucrosc‐glucose, while tablets with gum arabic‐maltitol and pectin‐gelatine‐Lycasin somewhat increased the pH values. To conclude, it is not recommended to exchange gum arabic for CMS in sugar‐free lozenges, since the cariogenic properties of the products are negatively affected.