Processing effect on soybean storage proteins and their relationship with tofu quality

Area of Science:

• Food Science
• Agricultural Science
• Biochemistry

Background:

• Soybean storage proteins, primarily glycinin (11S) and beta-conglycinin (7S), are crucial for tofu texture and quality.
• Variations in protein composition among soybean varieties can lead to inconsistent tofu characteristics.
• Previous studies have reported conflicting relationships between protein profiles and tofu quality, potentially due to differing processing methods.

Purpose of the Study:

• To investigate the impact of different processing methods on soybean storage protein composition in tofu.
• To determine the relationship between soybean 11S/7S protein ratios and the resulting tofu quality attributes.
• To explain discrepancies in prior research regarding soybean proteins and tofu quality.

Main Methods:

• Tofu preparation from 13 soybean varieties using three distinct methods: bench, pilot, and production.
• Analysis of glycinin (11S) and beta-conglycinin (7S) content in soybean varieties, soy milk, and tofu.
• Correlation analysis between soybean 11S/7S protein ratios and tofu quality parameters (hardness, yield, sensory attributes).

Main Results:

• Significant differences in glycinin and beta-conglycinin content were observed among soybean varieties.
• The 11S/7S protein ratio in tofu remained stable from soy milk for pilot and production methods.
• Processing methods significantly influenced tofu's 7S and 11S protein content, hardness, yield, and sensory quality.

Conclusions:

• Processing methods play a critical role in determining tofu quality by modulating soybean storage protein profiles.
• The 11S/7S protein ratio in soybeans is a reliable indicator of tofu quality, but this correlation is influenced by the processing technique.
• Acknowledging the impact of processing methods is essential for reconciling contradictory findings in soybean protein-to-tofu quality research.