Nutritional evaluation of different bacterial douchi.

Area of Science:

• Food Science
• Microbiology
• Biochemistry

Background:

• Bacterial douchi (BD) is a fermented soybean food with potential nutritional benefits.
• Understanding the biochemical changes during fermentation is crucial for optimizing its production and quality.

Purpose of the Study:

• To determine the protein, peptide, amino acid, lipid, and fatty acid composition of bacterial douchi (BD) produced by different pure starter fermentations.
• To compare these compositions with autoclaved soybean (AS).

Main Methods:

• Analysis of protein, peptide, amino acid, lipid, and fatty acid content in BD samples fermented with different pure starters.
• Comparison of results with autoclaved soybean (AS) as a control.

Main Results:

• Bacterial fermentation significantly increased protein and lipid content in BD compared to AS.
• Predominant amino acids included glutamic acid, proline, aspartic acid, leucine, and alanine, with threonine identified as the limiting amino acid.
• Triacylglycerol was the most abundant lipid, and major fatty acids were oleic, linoleic, and palmitic acids.
• Bacterial fermentation increased amino acid nitrogen and trichloroacetic acid soluble protein, and altered peptide molecular weight distribution.

Conclusions:

• Pure starter bacterial fermentation enhances the nutritional profile of douchi by increasing protein and lipid content.
• Fermentation modifies peptide profiles, contributing to the overall nutritional value of bacterial douchi.