Improvement of the quality of soy sauce by reducing enzyme activity in Aspergillus oryzae. (15th September 2019)

• Record Type: Journal Article
• Authors: Ding, Chengfang; Meng, Meng; Jiang, Yuyang; Hou, Lihua
• Is Part Of: Food chemistry. Volume 292(2019)
• Page Start: 81
• Page End: 89
• Publication Date: 2019-09-15
• Subjects: A. oryzae -- cis-CreA -- Cellulase -- Pectinase -- Soy sauce fermentation; Food -- Analysis -- Periodicals; Food -- Composition -- Periodicals; 664
• DOI: 10.1016/j.foodchem.2019.04.052
• Languages: English
• ISSNs: 0308-8146

Abstract

Highlights: A. oryzae 3.042-3 which can stably produce mononuclear spores was obtained. A. oryzae 3.042-3-c was constructed containing the fragment cis-CreA. The cellulase and pectinase of A. oryzae 3.042-3-c was reduced obviously. The salt-free solid content of A. oryzae 3.042-3-c was 204.10 g/L. HEMF of the flavor components was found in the soy sauce from A. oryzae 3.042-3-c. Abstract: How to effectively increase or decrease the ability of A. oryzae to produce enzymes was the key to improve the quality of soy sauce . However, multi-core property of A. oryzae resulted in genetic instability of the new strain. Here, A. oryzae 3.042-3 which can stably produce mononuclear spores was constructed based on A. oryzae 3.042. A. oryzae 3.042-3-c obtained by transformation of the fragment of cis-CreA into A. oryzae 3.042-3 exhibited genetic stability. The fragment containing the cis-acting and the promoter CreA from A. oryzae was connected to chromosome VII in A. oryzae 3.042-3-c. Compared with A. oryzae 3.042-3, the cellulase activity of A. oryzae 3.042-3-c was reduced by 50.5% and the pectinase activity was decreased by 10.0%. At the end of the soy sauce fermentation, the salt-free solid content of A. oryzae 3.042-3-c was higher 58.9% than that of A. oryzae 3.042-3. The kinds and contents of the flavor components of the soy sauce from the fermentation by A. oryzae 3.042-3-c were higher than those of the A. oryzae 3.042 and A. oryzae 3.042-3, especially in alcohols and esters. HEMF was only found in the soy sauce from A. oryzae 3.042-3-c. The results indicated that the new strain A. oryzae 3.042-3-c could improve the quality of soy sauce from the low-salt solid fermentation by decreasing enzyme activity of cellulase and pectinase.