Effects of Different Extraction Processes on the Structure and Functional Properties of Camellia Seeds Protein

Camellia oleifera seed meal as the main by-product of tea oil production, contains a large amount of unused high-quality plant protein. To explore the effects of ultrasound and enzyme treatment on protein during the extraction process, alkali dissolves acid precipitation (ADAP), enzyme extraction (EE), ultrasonic alkali dissolving acid precipitation (UADAP) and ultrasonic enzyme extraction (UEE) were used to extract protein from Camellia oleifera seed meal, and the structural and functional properties of the protein were compared and analyzed. The results showed that after ultrasonic treatment, the infrared peak of the amide I band shifted from 1629 cm⁻¹ to 1649 cm⁻¹, and the exposure of Trp residues within the protein molecules led to an increase in the fluorescence intensity of the protein. The proportion of ionic bonds in the intermolecular force increased to 31.17%. However, enzymatic treatment and alkali soluble acid precipitation treatment had little impact on the structure of protein, and there was no significant difference between the two methods. Through the comparison between ADAP group and UADAP group, it could be found that the emulsification, the gel hardness and the gel elasticity of protein increased by 34.43%, 51.36% and 38.13% after ultrasonic treatment, respectively. From the results of ADAP and EE groups, it was found that the emulsifying stability and foaming ability of the protein increased by 93.35% and 44.28% by enzymatic treatment, respectively, while the bubble stability of the protein increased by 53.11% after alkali soluble acid precipitation treatment.