1. Effect of Ultrafine Crushing on Aging Value of Mung Bean Starch
The essence of starch aging is that in the static process, the gelatinized starch molecules are arranged automatically and orderly, and hydrogen bonds are combined into bundles to reduce solubility. Branches of straight and branched chain molecules tend to be arranged in parallel, close to each other, and form hybrid microcrystalline beams through hydrogen bonding.
The aging value of mung bean starch is reflected by the water content of the gel. With the prolongation of ultramicro-treatment time, precipitation gradually increased, reached a high value within 20 minutes, and then gradually decreased. It can be seen that the aging degree of mung bean starch can be improved by appropriate ultratreatment time, while the aging degree of mung bean starch can be reduced by long-term ultratreatment. The reason may be that moderate ultramicro-treatment can cut off some amylopectin molecules in the amorphous region of starch granules, accelerate the re-coagulation of starch chains and the formation of microcrystalline bundles, and free release of bound water in starch molecules, thus improving the stability of starch. The aging degree of mung bean starch increased after long-term ultramicro-treatment. Molecular chains are decomposed into small molecules, which are not easy to form intermolecular hydrogen bonds and recrystallize. Ultrafine starch paste is more stable and not easy to aging.
2. Effect of Ultra-fine Crushing Time on the Formation of Resistant Starch
The effect of different ultrafine grinding time on the formation of resistant starch. The content of resistant starch increased gradually in 0-20 minutes with the extension of time, but decreased gradually in 30-50 minutes with the extension of time. The reason may be that the content of amylose in mung bean starch was changed by ultra-fine comminution. Ion treatment. The ratio of starch powder to amylopectin, the retrogradation rate and the number of starch grains are related.
In the crushing test of cassava starch, it was found that amylopectin was easier to crush than amylose. Crushing treatment can reduce the branch of amylopectin and increase amylose and intermediate components. Amylose is a short molecular chain amylose which is difficult to aggregate in gelatinized starch paste because of its fast movement, fast diffusion and difficult aggregation. Amylose has high intermolecular repulsion and difficult aggregation. It is easy to regenerate resistant starch in gelatinized starch paste. Moderate reduction of amylose segments in mung bean starch is beneficial to the formation of resistant starch, but excessive ultrafine comminution will also reduce the number of amylose segments, making it difficult for amylose to form double helix, on the contrary, reducing the content of protein. D resistant starch.
The results showed that the aging degree of mung bean starch and the formation of mung bean starch could be improved by ultrafine treatment for 20 minutes. The results show that vibration superfine grinding is an effective pretreatment method to improve the content of resistant starch in starch products.
Vibration superfine grinding can promote the aging of starch products, that is, to form resistant starch. It can be used to improve the preparation process of resistant starch. Ultrafine grinding time is an important factor affecting the performance of samples. Attention should be paid to the process.