Dissertation > Industrial Technology > Light industry,handicrafts > Food Industry > Starch Industry > Basic theory

Research on Low DE Maltodextrins from Rice Starch

Author ChengXiaoXu
Tutor LinQinLu
School Central South University of Forestry Science and Technology
Course Of Food Science
Keywords Rice starch The low DE maltodextrin Thermostable α- amylase Rheology Gelatinization Textural properties
Type Master's thesis
Year 2010
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Fat is an integral part of human health nutrients, can provide the heat of 37.8 kJ / g, and can only produce heat of 16.72 kJ / g protein and carbohydrate. However, excessive intake of fats will harm human health and increase the incidence of cancer, prone to obesity, cardiovascular diseases such as fatty liver, high cholesterol, high blood pressure. How to replace the grease of high-calorie foods, reduce fat intake, has become a popular research direction. In recent years, countries have committed to the research and development of fat substitutes, has been extensive use of fat substitutes to replace part of the fat in food formulations. The low DE value (lt; 6) of maltodextrin capable of forming a soft, stretchable, thermoreversible gel, and melts, so that products with a fat-like mouthfeel, fat substitutes can be used as well. In this study, the high temperature a-amylase hydrolyzed rice starch, low DE value of maltodextrin, a the rice starch preparation maltodextrin best conditions determined by orthogonal test, and the low DE malt dextrin The rheological properties and pasting properties were determined to provide a certain theoretical basis to promote the comprehensive development and utilization of rice starch food resources. The main conclusions are as follows: 1, by orthogonal experiment, the preparation of rice starch low DE maltodextrin process parameters: rice starch concentration of 25%, high-temperature a-amylase 24u / g starch hydrolysis time 10mmin, the role of a temperature of 90 ° C. Under this condition, the resulting low DE maltodextrin of DE value of 2.9. 2, rice starch and maltodextrin are non-newtonian pseudoplastic fluid. At the same temperature, the sample shear stress is increased with increasing shear rate; viscosity decreases with the increase of the temperature and shear rate, shear thinning; of maltodextrin concentration increase the impact on the viscosity With The elevated temperature becomes small; DE value is increased, i.e. the increase in the degree of starch hydrolysis of the maltodextrin viscosity decreases, and this decrease the performance was more evident in the low temperature and low shear rate conditions. 3, starch Lake of a first-order phase transition, DSC can study the different effects of different factors of the phase change process. The larger the DE value, the lower the degree of aging, the better the stability of the maltodextrin solution. With the increase in the degree of the sample stream, the absorption peak of the DSC gelatinization curve gradually widened Bianai shifted to the high-temperature direction, the gelatinization temperature range gradually becomes large. Reflecting the high degree of enzymatic hydrolysis serious damage to the internal structure of the starch granules, the starch degradation the gelatinization process more complex. 4, the rice starch, the viscosity variation with temperature was a regular increase (up to the maximum viscosity), a decrease (up hot viscosity), then increased (up to the viscosity of the cold glue) process, so as to constitute a typical RVA Pro. RVA Profile of the maltodextrin is very obvious, and the operation was conducted at a starting temperature of 50 ° C for less than 1 minute, the viscosity reaches a maximum, and then decreased rapidly, the viscosity no longer rebound the RVA Profile eigenvalues ??almost constant . 5, Low DE maltodextrin as fat substitutes to replace part of the fat in the bread texture analysis and sensory evaluation, Low DE maltodextrin on bread quality. The results showed that: under the conditions of the test, the bread dough, add 30? 2.9 maltodextrin compared with the first wife aspects Mission, there was some improvement in the textural properties and sensory scores.

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