Method for detecting cross-linking degree of cross-linked starch

Abstract

The invention discloses a method for detecting the cross-linking degree of cross-linked starch. The method comprises the following steps: 1, chemically gelatinizing: uniformly mixing (100 + / - 0.5) mgof dry starch with 1-2 mL of an ethanol solution, adding 8-9 mL of a sodium hydroxide solution having a concentration of 1-2 mol / L, and performing chemical gelatinization for 10-30 min; 2, performinga chromogenic reaction: preparing a blank solution, and detecting absorbance; and 3, calculating the cross-linking degree: determining the cross-linking degree CL% according to the average absorbanceA of native starch and the average absorbance a of the cross-linked starch by the following relation: CL% = [(A-a) / A] * 100%. Compared with traditional methods, the method in the invention has the characteristics of sensitivity, high efficiency, scientific property, convenience, reflection of the true situation of a cross-linking reaction through characterizing the cross-linking degree of the starch having different cross-linking degrees, accurate and reliable result, and realization of the detection of the cross-linking degree of the cross-linked starch in a wide range under a safe condition.

Description

technical field [0001] The invention relates to a starch detection method, in particular to a method for detecting the cross-linking degree of starch, which is a method for measuring the cross-linking degree of cross-linked starch with a wide range and different degrees. Background technique [0002] There are two opposite mechanisms in the cross-linking process of starch. On the one hand, the cross-linking reaction inhibits the dissolution of soluble small molecules, which can increase the dry matter of starch paste, thereby increasing the viscosity of starch paste; on the other hand, cross-linking inhibits the dissolution of starch granules. The expansion of starch particles reduces the volume of starch granules and reduces the viscosity of starch paste. When the degree of cross-linking reaches a certain level, the viscosity of cross-linked starch will not be detected. [0003] The traditional methods for characterizing the degree of crosslinking mainly include viscosity m...

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Problems solved by technology

All three methods cannot accurately and comprehensively reflect the degree of cross-linking of starch due to their respective limitations.

And the method of phosphorus content is in the cross-linking process of starch, the change of the physical and chemical properties of starch to the addition amount of lower cross-linking agent is bigger; The change in properties is not obvious, and the phosphorus content does not really reflect the change in the physical and chemical properties of starch

[0006] For the swelling force method, the amount of sample used for the detection of the swelling force is relatively large. For a relatively low amount of cross-linking agent added, there is no difference in the swelling of cross-linked starch compared with the original starch. Generally speaking, the swelling force of cross-linked starch decreases with the increase of cross-linking agent, but the degree of cross-linking and the amount of cross-linking agent added are not in a linear relationship. If the amount of cross-linking agent added continues to increase, the volume reading cannot Distinguish cross-linked starches with different amounts of cross-linking agent added

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