Noncarbohydrate, low-digestibility carbohydrate ingredients impact starch gelatinization.Low-carbohydrate foods and ingredients have attracted much attention. Our interest in these products has intensified with our increased awareness of obesity as a public health concern. The effect of low-carbohydrate or low-digestibility carbohydrate materials on starch gelatinization Starch gelatinization is a process that breaks down the intermolecular bonds of starch molecules in the presence of water and temperature and allows the hydrogen bonding sites (the hydroxyl hydrogen and oxygen) to engage more water. and their use in baked goods was investigated by scientists at Purdue University Purdue University (pərdy  `, -d`), main campus at West Lafayette, Ind. . Their objective was to
determine the effect of xylitol xylitol /xy·li·tol/ (zi´li-tol) a five-carbon sugar alcohol derived from xylose and as sweet as sucrose; used as a noncariogenic sweetener and also as a sugar substitute in diabetic diets. , soy protein Soy protein is generally regarded as the storage protein held in discrete particles called protein bodies which are estimated to contain at least 60–70% of the total soybean protein. isolate, inulin inulin /in·u·lin/ (in´ul-in) a starch occurring in the rhizome of certain plants, yielding fructose on hydrolysis, and used in tests of renal function. in·u·lin n. and resistant starch Resistant starch (RS) is starch that escapes digestion in the small intestine of healthy individuals.1 Resistant starch is considered the third type of dietary fiber, as it can deliver some of the benefits of insoluble fiber and some of the benefits of soluble fiber. on the cooking properties of corn starch. The investigators also wanted to see how feasible it would be to prepare a muffin containing these ingredients, while replacing 50% of the flour and 50% of the sucrose. It's clear that ingredients affect starch gelatinization, and this must be taken into account in formulating baked goods. Control muffins were prepared using a standard recipe. The test muffins had 50% of the flour replaced with 20% soy protein isolate, 20% inulin and 10% resistant starch. The muffins were stored for five days. Researchers took texture, water activity and color measurements. They found that muffins containing 50% less flour and sucrose could be formulated that were not significantly different in texture or water activity from the control muffins. But the test muffins were significantly darker, and varying cooking time may be required to produce a muffin closer in appearance to the control. Experiments showed that increasing the amount of soy isolate, xylitol or resistant starch increased the peak and final viscosities of the products. Inulin showed the opposite behavior, generating a decrease in peak and final viscosities as inulin concentrations increased. The impact of inulin requires further study. Texture values for the control and test muffins were not statistically different at any time. Water activity was only statistically significant on the second day. Hunter L (34.8 compared to 22.3), a (16.1 compared to 12.4) and b (17.3 compared to 9.3) values were different between the control and test muffins. Further information. James Daniel, Department of Foods and Nutrition, Purdue University, Stone Hall, West Lafayette West Lafayette, city (1990 pop. 25,907), Tippecanoe co., W Ind., a suburb of Lafayette, on the Wabash River; inc. 1924. A primarily residential city, it is the seat of Purdue Univ. , IN 47907; phone: 765-494-8256; fax: 765-494-7953; email: danieljr@purdue.edu. |
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