Author
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Rendleman Jr, Jacob |
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Submitted to: Biotech and Applied Biochemistry
Publication Type: Peer Reviewed Journal Publication Acceptance Date: 3/28/2000 Publication Date: N/A Citation: N/A Interpretive Summary: Starch in the U.S., particularly starch from corn, is produced in large quantity. New and expanded markets are needed to utilize this renewable resource. Cyclodextrins, which can be made from starch by means of certain enzymes, are products with numerous commercial applications and are being used increasingly by the agricultural, pharmaceutical, cosmetic, and food industries. An enzyme-based process was recently discovered that permitted the conversion of cyclodextrin into highly insoluble amylose (straight-chain starch) of low molecular weight. This insoluble form of starch was shown to be highly indigestible under conditions similar to those in the human small intestine and, therefore, has potential as a non-digestible, "low- calorie" component in foods. This information should be useful not only to starch and cyclodextrin manufacturers but also to scientists who plan to use low-molecular-weight amyloses in their research. Creating new products will ultimately create greater demand for corn products in the marketplace and provide the consumer with goods of better quality and lower cost having unique characteristics. Technical Abstract: High-amylose starches of low degree of polymerization (dp 61-71), formed as fine granules by interaction of Bacillus macerans glucanotransferase with alpha-cyclodextrin (CD) at 2-70 deg C, are highly insoluble in water and not gelatinizable under normal cooking conditions (100 deg C). Samples of CD-derived starches, both cooked and uncooked, were subjected to in vitro hydrolysis by human salivary alpha-amylase at 37 deg C under conditions chosen to resemble those in the human intestinal lumen. Released low-molecular-weight saccharides were determined quantitatively by HPLC and the results compared with those from similar studies with natural starches. Among uncooked starches, CD-derived starch ranked very low in reactivity toward alpha- amylase, along with potato starch and a high-amylose hybrid corn starch (64% amylose). Cooking greatly enhanced reactivity of natural starches, but only moderately increased reactivity of CD-derived starches. Susceptibility to hydrolysis of cooked starches increased in the following general order: CD-derived starch (~100% amylose) < 100% corn amylose (isolated by the 1-butanol method) < hybrid high-amylose corn starch (64-66% amylose) < waxy maize starch (99-100% amylopectin), ordinary corn starch (~25% amylose) < potato starch (~25% amylose). |
