Document Type : Research Paper
Abstract
Starch is a versatile and useful polymer having physicochemical properties that can be altered by chemicals or enzymatic modification and/or physical treatment. Native starches possess many disadvantages that decrease their application and industrial use, but could be modified to obtain the desired properties to meet industrial needs for a wide range of starch applications. Physically modified starches are considered to be very safe, natural materials. Power ultrasound appears to be an effective process for modification of starch. Natural wheat and potato starches were sonicated under different conditions and their physical properties were investigated. Studies on starch pasting properties have shown that starches treated with power ultrasound had lower peak viscosities and higher pasting stability than did native starch. Ultrasound treated starches exhibited an increase in pasting temperature. Sonication also induced the starch paste to become more transparent and less viscose. The same treatments were applied for potato starch and showed almost the same patterns and effects, but indicated that temperature and amplitude are more important. Most changes occurred at temperatures higher than that of gelatinization because of structural changes in the granules. Data collected at different stages were analyzed using a factorial experimental design and means were evaluated in the form of mathematical models with linear and 3D-surface charts. Power ultrasound may be applied for the preparation of a physically modified starch that has good clarity and low viscosity and also aids the production of thin boiling starch produced by chemical treatments such as acid or oxidation.
Keywords
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