Preparation of soy sauce by walnut meal fermentation: Composition, antioxidant properties, and angiotensin‐converting enzyme inhibitory activities

Food Science & Nutrition

卷:8

Feng Jin¹  Jing Hao¹  Jie Xu¹  Fengjun Wang¹  Joe M. Regenstein² 

[1] Beijing Key Laboratory of Forest Food Processing and Safety Department of Food Science and Engineering College of Biological Sciences and Biotechnology Beijing Forestry University Beijing China;

[2] Department of Food Science Cornell University Ithaca NY USA;

关键词: ACE inhibitory activity;    amino acid;    antioxidant activity;    soy sauce;    walnut;   

DOI  :  10.1002/fsn3.1453

来源: DOAJ

【 摘 要 】

Abstract Remaining walnut meal after oil extraction still contains many nutrients. However, these by‐products have not been effectively used. In this study, walnut meal and Aspergillus oryzae (3.042) were used in combination to prepare a soy sauce‐like material with high amino nitrogen content (ANC). The optimal conditions for the preparation of walnut soy sauce (ratio of brine:koji of 1.7:1 for 6 days at 45°C) were determined using response surface experiments (RSE), which showed maximum ANC of 855 mg/100 ml. The results of amino acid analysis indicated that walnut soy sauce had a similar amino acid composition compared with three commercial soy sauces. It contained all the essential amino acids and had a high content of umami amino acids such as Glu and Asp, which may give it a stronger umami taste. Moreover, the crude walnut soy sauce was extracted sequentially using ethyl acetate, n‐butanol, acetone and water, and the total phenols, total flavonoids, reducing sugars, and the peptides of different solvent extracts were measured. Results showed that the total phenolic and flavonoid contents were highest in the ethyl acetate extracts. However, water residue had the highest levels of reducing sugars and peptides. In vitro, the water residue showed the highest antioxidant capacity and angiotensin‐converting enzyme (ACE) inhibitory activity, due to more reducing sugars and peptides. These results indicated that walnut soy sauce may have significant antioxidant and ACE inhibitory activity. The findings provide a scientific basis for developing a replacement for soy sauce and broaden the beneficial application of walnut meal.

【 授权许可】

Unknown