High-salt Liquid-state Soy Sauce Research Articles

High-intensity ultrasound promoted the maturation of high-salt liquid-state soy sauce: A mean of enhancing quality attributes and sensory properties

High-intensity ultrasound was used as a means to promote maturation of soy sauce. The optimal conditions for ultrasound treatment were 90℃ at an ultrasound intensity of 39.48 W/cm2 for 60 min. The total reducing sugars and soluble salt-free solids content was significantly increased after ultrasound-assisted maturation. The free amino acid content was significantly decreased, mainly due to the Maillard reaction (MR). The promoted MR produced several types of flavor compounds, including esters, pyrazines, and ketones, which imparted an attractive aroma to the maturated soy sauce. The proportion of peptides with a molecular weight of 1–5 kDa provided umami as an important flavor characteristic, and the content in the ultrasound-matured soy sauce (10.19 %) was significantly higher than that in the freshly prepared soy sauce (8.34 %) and the thermally treated sample (8.89 %). Ultrasound-assisted maturation would improve product quality and meanwhile, shorten the duration and reduce the cost for the soy sauce industry.

Characterization of key odor-active compounds in high quality high-salt liquid-state soy sauce

Solid-phase microextraction and liquid–liquid extraction with gas chromatography– olfactometry–mass spectrometry (GC–O–MS) were used to analyze four award-winning high-salt liquid-state soy sauces (HLS). In this study, 110 volatile odor compounds were detected using GC–O–MS. Twenty key odor-active compounds with a flavor dilution factor ≥ 1024 were identified through aroma extract dilution analysis(AEDA), of which 11 compounds had odor activity values > 1; these were methional, 4-hydroxy-2,5-dimethyl-3(2H)-furanone (HDMF), guaiacol, 4-hydroxy-2(or 5)-methyl-5(or 2)-ethyl-3(2 H)-furanone (HEMF), 1-hydroxy-2-propanone, 3-hydroxy-4,5-dimethyl-2(5H)-furanone, 2-ethyl-6-methylpyrazine, 3-methyl-1-butanol, 2,6-dimethylpyrazine, ethyl benzoate, and 4-ethylguaiacol. Sensory evaluation showed that roasted, cooked potato-like, seasoning-like, and smoky odors were the main odor characteristics in the award-winning HLS. Electronic nose analysis indicated that the odor characteristics of the four samples were significantly different and could be distinguished from each other. This study helps to understand and explore the odor characteristics and key odor components of the award-winning HLS.

Characterization of odor-active compounds in high-salt liquid-state soy sauce after cooking

GC × GC–O–MS was used for the aroma extract dilution analysis of cooked high-salt liquid-state soy sauce (HLS), wherein a number of components exhibited high flavor dilution (FD) factors. Electronic nose analysis showed that the heating temperature had a greater influence on the odor characteristics of soy sauce than the heating time. Sensory evaluation and the FD factor of odor-active compounds suggested that the caramel-like/sweet, roasted/roasted nut-like and spicy/burnt odor intensities of the boiled soy sauce were stronger than following heating at a higher temperature. These results indicate that different heating conditions could change the intensities of caramel-like/sweet, roasted/roasted nut-like and spicy/burnt in soy sauce during cooking by the concentrations changing of corresponding odor-active compounds. This study can provide basic data for the application of HLS aroma in food processing, and provides a reference for the application of HLS aroma in daily cooking and diet.

Characterization of key odor-active compounds in commercial high-salt liquid-state soy sauce by switchable GC/GC × GC–olfactometry–MS and sensory evaluation

Activity of odor compounds of soy sauces has not been fully determined so far. Herein, a new switchable GC/GC × GC–olfactometry–mass spectrometry system for simultaneous GC × GC–MS analysis and sniffing of each odor-active substance through a single injection was used for the aroma extract dilution analysis of five regular high-salt liquid-state soy sauces (HLS). Methional, maltol, guaiacol, 4-ethylguaiacol, 2-acetylpyrrole, 2-acetylfuran, 2-phenylethanol, and 4-hydroxy-2,5-dimethyl-3(2H)-furanone showed high flavor dilution (FD) factors. The FD factors of all odor-active compounds in different odor attributes were summed up (score) to evaluate the odor characteristics of the samples. Cooked potato-like odor was the most important characteristic. The difference in the odor characteristics were mainly reflected in the balance of caramel-like/sweet, roasted/roasted nut-like, spicy/burnt, and unpleasant odor intensity; the fruity odor intensity was the weakest. This study will provide a better understanding of the odor characteristics and key odor-active compounds in Chinese regular commercial HLS.

Investigation of the synthesis of biogenic amines and quality during high-salt liquid-state soy sauce fermentation

Soy sauce is a traditional fermented food in Asia. In this study, we determined the contents of biogenic amines (BAs) in commercial high-salt liquid-state fermented (HLF) soy sauce. Using high performance liquid chromatography (HPLC), we evaluated the effects of salinity on the synthesis of BAs during soy sauce fermentation. According to the results, various grades of HLF soy sauce demonstrated significant differences (p < 0.05) in the contents of BAs. The major BAs in laboratory-made soy sauce include spermidine (SPD), histamine (HIS), and tyramine (TYR). After fermentation, the contents of SPD, HIS, and TYR in the 20% salinity group were significantly (p < 0.05) reduced than those in the 16% and 18% salinity groups, suggesting that the salinity might be a crucial factor for reducing the biogenic amines during HLF soy sauce fermentation. We also found a positive correlation between the contents of amino nitrogen and biogenic amines.

Characterization of key aroma compounds in traditional Chinese soy sauce through the molecular sensory science technique

Sensory evaluation revealed that traditional high-salt liquid-state soy sauce (THLS), a popular seasoning in China, has a caramel-like/sweet, roasted, nutty, cooked potato-like, and spicy/burnt aroma. As a comparative sample, commercial high-salt liquid-state soy sauce (CHLS) showed a similar aroma profile; however, the aroma intensity was stronger and richer in THLS. Gas chromatography−olfactometry−mass spectrometry and aroma extract dilution analysis of the aroma concentrates, prepared by solvent-assisted flavor evaporation, revealed the presence of over 70 odor-active compounds. Among them, methional had the highest flavor dilution factor. Maltol, 4-ethylguaiacol, and phenylacetaldehyde were detected with a higher flavor dilution factor in THLS than in CHLS. Quantitative analysis indicated that the concentrations of 11 key aroma compounds were higher in THLS than in CHLS. The sensory evaluation suggested that the aroma profile of the aroma recombination sample was similar to that of THLS. HEMF, 2-acetyl-1-pyrroline, methional, HDMF, 4-ethylguaiacol, phenylacetaldehyde, 2,3-diethylpyrazine, 2-phenylethanol, furfuryl alcohol, 2,3-butanediol, and maltol imparted the overall aroma profile to THLS.

Comparative analysis of salt‐tolerant gene HOG1 in a Zygosaccharomyces rouxii mutant strain and its parent strain

A higher-salt-tolerant mutant strain Zygosaccharomyces rouxii 3-2 (strain S3-2) that could be used for improving the flavour of high-salt liquid state soy sauce was previously constructed from parent strain Z. rouxii (strain S) by genome shuffling. However, whether the mutations in this strain affect HOG1 encoding MAPK Hog1p and improve intracellular glycerol production remains to be elucidated. Although two mutations in the ORF and one in the promoter of the HOG1 gene sequence of strain S3-2 occurred compared with that of strain S, there was no significant difference in secondary and tertiary structures between S3-2Hog1p and SHog1p. It was found that the expression level of S3-2HOG1 was higher than that of SHOG1 in YPDN medium with high salt concentration. Furthermore, overexpression of S3-2HOG1 in Saccharomyces cerevisiae W303-1A could improve the salt tolerance and osmotolerance of engineered yeast compared with that of SHOG1. Enhancement of the transcription level of HOG1 induced by mutation in the promoter region may be one of the main reasons for the improved salt tolerance of strain S3-2 compared with that of strain S. Considering food security, the conservation of S3-2HOG1 would be beneficial for application of strain S3-2 in the fermentation of soy sauce.