Metabolomics mechanism of traditional soy sauce associated with fermentation time

Given that fermentation time has significant impact on quality and flavor of soy sauce,a global understanding of the metabolic mechanism as fermentation time prolonged is essential for producing satisfactory and consistent quality of traditional soy sauce.Herein,the metabolic compounds changes of soy sauce associated with fermentation time up to 10 years were comprehensively investigated by using Chinese traditional fermented soy sauce(CTFSS)as a demonstration.Results showed that formaldehyde nitrogen,total soluble nitrogen(TSN),non-salt soluble solids,amino acids,free 5’-nucleotides and volatile compounds in CTFSS changed obviously during fermentation.Specifically,glutamic acid and aspartic acid were prominent in CTFSS.Continuous decrease in content of hypoxanthine(Hx)was found from 1 M(1-month soy sauce)to7 M(7-months soy sauce).Furthermore,a significant opposite tendency for changes between some volatile compounds and amino acids was indicated that there was a transformation between these two components.Therefore,a better understanding to the influence of fermentation time on soy sauce had been proposed.As the formation and conversion of amino acids and sugars might be mainly responsible for flavor formation in CTFSS,the ratio of these two reactions rate led the metabolism to be divided into three steps,degradation,conversion and balance.

Determination of Quality Properties of Soy Sauce by Support Vector Regression Coupled with SW-NIR Spectroscopy

The modern near-infrared(NIR) spectroscopy analysis is a simple, efficient and nondestructive technique, which has been used in chemical analysis in diverse fields. Shortwave NIR spectroscopy is also a rapid, flexible, and cost-effective method to control product quality in food industry. The method of support vector regression coupled with shortwave NIR spectroscopy was explored for the nondestructive quantitative analysis of the important quality parameters of soy sauce, including amino nitrogen content, total acid content, salt content and color ratio. In this study, the support vector regression(SVR) models based on subtractive spectra and positive spectra were found and compared, the results show that the subtractive spectrum was more excellent than the positive spectrum. Meanwhile, R and RSE were determined, respectively, by means of original spectra and pretreated spectra[standard normal variate (SNV), first-derivative and second-derivative], and the corresponding models were successfully established. The best prediction was achieved by a support vector regression model of the first derivative transformed dataset. In addition, the result obtained by the proposed method was compared with that of Partial Least Squares(PLS), which showed that the generalization performance of the classifier based on SVR was much better than that of PLS. The results demonstrate that shortwave NIR spectroscopy combined with SVR is promising for the quality control of soy sauce.

The Role of Nutrition Education in the Promotion of Iron-Fortified Soy Sauce in China

Iron deficiency anemia （IDA） is one of the most important nutrition issues in China. Data from the 2002 National Nutrition and Health Survey showed that the average anemia prevalence in China was 20.1% and the prevalence in women of child-bearing age and of children in some poor regions reached more than 50%; it has been estimated that more than 200 million Chinese people are suffering from anemia. Anemia significantly affects physical and mental development in children, decreases productivity in adults, and reduces immune function among the population at large, which leads to a lower health status and limits social development.

Visible and Near-Infrared Spectroscopic Discriminant Analysis Applied to Identification of Soy Sauce Adulteration

The identification of soy sauce adulteration can avoid fraud, and protect the rights and interests of producers and consumers. Based on two measurement models (1 mm, 10 mm), the visible and near-infrared (Vis-NIR) spectroscopy combined with standard normal variate-partial least squares-discriminant analysis (SNV-PLS-DA) was used to establish the discriminant analysis models for adulterated and brewed soy sauces. Chubang soy sauce was selected as an identification brand (negative, 70). The adulteration samples (positive, 72) were prepared by mixing Chubang soy sauce and blended soy sauce with different adulteration rates. Among them, the “blended soy sauce” sample was concocted of salt water (NaCl), monosodium glutamate (C5H10NNaO5) and caramel color (C6H8O3). The rigorous calibration-prediction-validation sample design was adopted. For the case of 1 mm, five waveband models (visible, short-NIR, long-NIR, whole NIR and whole scanning regions) were established respectively;in the case of 10 mm, three waveband models (visible, short-NIR and visible-short-NIR regions) for unsaturated absorption were also established respectively. In independent validation, the models of all wavebands in the cases of 1 mm and 10 mm have achieved good discrimination effects. For the case of 1 mm, the visible model achieved the optimal validation effect, the validation recognition-accuracy rate (RARV) was 99.6%;while in the case of 10 mm, both the visible and visible-short-NIR models achieved the optimal validation effect (RARV = 100%). The detection method does not require reagents and is fast and simple, which is easy to promote the application. The results can provide valuable reference for designing small dedicated spectrometers with different measurement modals and different spectral regions.

DETERMINATION OF ORGANIC ACIDS IN SOY SAUCE BY HPLC

Organic acids in 3 kinds of soy sauces were analyzed by HRLC.Column:C18 ()Bondapak(10μm,3.9mm i.d.* 30cm;mobile phase:0.5%(NH_4)_2HPO_4(pH=2.9);flow rate:1.0 ml/m.PT-C18 cartridge was used for the sample preparation.Recoveries of organic acids are between 96-111%.

Screening and Characterization of Nitrite Degrading <i>Lactobacillus plantarum</i>in Chinese Traditional Pickles

A Gram-positive, non-spore, round ended, straight rod Lactic acid bacteria were screened. The strain was screened out from the traditional pickle jar in Yutang soy sauce garden of Jining. In order to degrade the nitrate content in the fermentation process of traditional pickles and improve the quality of pickles, it is necessary to screen out nitrite degrading strains from pickles, and preliminarily locate nitrite reductase, and find out the most suitable pH, temperature and culture time to degrade nitrite. Lactobacillus plantarum was screened by MRS medium in advance. After 48 hours of culture in a shaking table with Bacillus subtilis, the cell components were separated by centrifugation, wall breaking and other operations. After 20 hours at 30°C, the content of nitrite in each component was determined by the naphthalene ethylenediamine hydrochloride method (NIR). The culture conditions were as follows: inoculation amount 3%, 6%, 9%, 12%, 15%;salinity 2%, 4%, 6%, 8%, 10%;temperature 15°C, 20°C, 25°C, 30°C, 35°C for 20 h. The results showed that the best degradation effect of nitrite was obtained under the conditions of 9% inoculum, salinity 5% and 30°C. Under the conditions of 9% inoculum, 5% salinity and 30°C for 5 h, 10 h, 20 h, 48 h, 66 h and 78 h, the results showed that the degradation amount gradually increased with the extension of time, and gradually maintained a stable state. Lactobacillus plantarum JBA-3 is a new type of lactic acid bacteria which can degrade nitrite and produce nitrite reductase.