Oil body extraction from high-fat and high-protein soybeans by laccase cross-linked beet pectin: physicochemical and oxidation properties

BACKGROUND

Soybean oil bodies (SOB) are droplets of natural emulsified oil. Soybean oil emulsifies well but it is easily oxidized during storage. Beet pectin is a complex anionic polysaccharide, which can be adsorbed on the surface of liposomes to improve their resistance to flocculation. Laccase can covalently cross-link ferulic acid in beet pectin, and its structure is irreversible, which can improve the stability of polysaccharides.

RESULTS

At pH 2.5, laccase cross-linked beet pectin high-oil soybean oil body (HOSOB) and high-protein soybean oil body (HPSOB) emulsions showed obvious aggregation and severe stratification, and the oxidation of the emulsions was also high. The flocculation of emulsions decreased with an increase in the pH. The effect of pH on the flocculation of emulsion was confirmed by confocal laser electron microscopy. The ζ potential, emulsification, and rheological shear force increased with increasing pH whereas the particle size and surface hydrophobicity decreased with increasing pH.

CONCLUSION

This experiment indicates that the physicochemical stability of the two composite emulsions was strongly affected under acidic conditions but stable under neutral and weakly alkaline conditions. Under the same acid-base conditions, the degree of oxidation of HPSOB composite emulsion changes substantially. The results of this study can provide a basis for the design of very stable emulsions to meet the demand for natural products. © 2023 Society of Chemical Industry.

Tremella fuciformis polysaccharides as a fat substitute on the rheological, texture and sensory attributes of low-fat yogurt

The potential of Tremella fuciformis polysaccharides (TFPS) as a fat substitute in low-fat yogurt was evaluated in this study. The effects of adding different concentrations of TFPS solution on the physical and chemical properties, texture, rheology, microstructure and sensory properties of low-fat yogurt were evaluated. Compared with control, the addition of TFPS not only increased the solid content and water holding capacity of yogurt, but also reduced syneresis losses in low-fat yogurt. In fact, the addition of TFPS did not affect the color of yogurt but had a positive effect on the texture and sensory of yogurt. In terms of rheology, all low-yogurt samples exhibited rheological to the weak gel-like structures (G' > G″), and the storage modulus and loss modulus of the yogurt added with TFPS were higher than those of the low-fat yogurt control group. Compared with the low-fat yogurt control group, yogurt added TFPS makes the cross-linking of polysaccharides and casein more compact. In conclusion, TFPS has potential as a fat substitute in dairy products.

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TFPS with Medicine Food Homology can be used as a fat substitute for low-fat yogurt.

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TFPS significantly improved the physical and chemical properties of low-fat yogurt.

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0.025% TFPS in low-fat yoghurt was most acceptable in the sensory score.

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Polysaccharide-protein interactions enhanced protein network structure.

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TFPS improved overall organoleptic quality of low-fat yogurt.

Zizania latifolia Cell Wall Polysaccharide Metabolism and Changes of Related Enzyme Activities during Postharvest Storage

The metabolism of polysaccharides in the Zizania latifolia cell wall helps maintain the postharvest quality during storage. Fresh Z. latifolia was stored at 4 °C and 25 °C to evaluate the hardness, cell wall polysaccharide composition, cell wall structure, active ingredients, and cell wall metabolism-related enzyme activities. The results showed that hardness declined concomitantly with an increase in water-soluble pectin content during storage, as well as with a decrease in propectin and cellulose contents. Correlation analysis showed that lower activities of cell wall-degrading enzymes, such as polygalacturonase, cellulase, and β-galactosidase in Z. latifolia stored at 4 °C, were associated with lighter fiberization and greater hardness, compared with those stored at 25 °C. Additionally, the results of infrared spectroscopy showed that texture softening may be attributed to a decrease in the degree of esterification of water-soluble polysaccharides at 25 °C compared to that at 4 °C.