Woo, Wing Yann (2025) Effect of Bacillus Subtilis Var. Natto Fermentation on Soybean: a Comparative Study between Black and Yellow Varieties. Final Year Project (Bachelor), Tunku Abdul Rahman University of Management and Technology.
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Abstract
Soy milk is valued for its digestibility and health benefits, while okara, a byproduct of soy milk, is known for its protein and fiber content. Previous studies suggest that fermentation can enhance protein digestibility and antioxidant activity while reducing anti-nutritional factors. This study investigates the effects of Bacillus subtilis var natto fermentation on the chemical (total phenolic content (TPC), total flavonoid content (TFC)), physicochemical (pH, total titratable acidity), and bioactive (antioxidant (DPPH, ABTS, FRAP), anti-inflammatory (proteinase inhibition and anti-lipoxygenase activities), and anti-thrombolytic activity properties of yellow and black soy milk and okara. Soy milk was extracted from yellow and black soybeans, and the corresponding okara was collected. Both soy milk and okara were fermented at 37°C for 24 hours at 180 rpm shaking. Post-fermentation, a significant reduction (p < 0.05) in total crude protein and soluble protein content was observed in both yellow and black okara. Total soluble protein of all soy milks was decreased significantly (p < 0.05) post-fermentation. The pH of soy milk decreased significantly (p < 0.05) after fermentation, while the pH of okara slightly increased, likely due to the buffering effects of proteins and fibers. Total titratable acidity increased across all samples, indicating the production of organic acids by B. subtilis . After fermentation, TPC decreased in soy milks but increased in okara, while the opposite trend was observed for TFC. Antioxidant and anti-inflammatory activities showed a significant increase (p < 0.05) across all samples. Interestingly, anti-thrombolytic activity decreased after fermentation in all samples except black okara, which retained significant activity, suggesting that B. subtilis fermentation may enhance thrombolytic activity. This study demonstrates that B. subtilis fermentation positively impacts the bioactive properties of soy milk and okara, with black soy showing superior bioactivity. Further research is needed to optimise fermentation and identify the bioactive compounds responsible for these effects.
Item Type: | Final Year Project |
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Subjects: | Technology > Food Technology |
Faculties: | Faculty of Applied Sciences > Bachelor of Science (Honours) in Food Science |
Depositing User: | Library Staff |
Date Deposited: | 27 Dec 2024 04:12 |
Last Modified: | 27 Dec 2024 04:12 |
URI: | https://eprints.tarc.edu.my/id/eprint/31370 |