Acetic acid reducing the softening of lotus rhizome during heating by regulating the chelate-soluble polysaccharides.

Lotus rhizomes were used to study on the relationship between the cell wall polysaccharides and cooked texture by adding acetic acid. Hardness and scanning electron microscopy results showed that acetic acid treatment can maintain higher hardness and the integrity of the cell wall. Then, the cell walls were sequentially extracted and divided into water-soluble fraction, chelate-soluble fraction (CSF), sodium carbonate-soluble fraction and hemicellulose fraction. The pectin fraction contents, monosaccharides composition, esterification degree and sugar ratios in different groups were evaluated, the results showed that acetic acid increased the total amount of CSF, decreased the esterification degree and less side chain compared that in the solely thermal treatment group. The nanostructures showed that acetic acid treatment maintained longer chain and destroy helical structure of CSF backbone. This work helps us to demonstrate the relationship between polysaccharides structure and cooked texture, and further control the plant-based vegetables processing texture in food industry.