Effects of thermal and nonthermal processing technology on the quality of red sour soup after storage

Sodium dehydroacetate-induced disorder of coagulation function in broiler chickens and the protective effect afforded by vitamin K

Sodium dehydroacetate (S-DHA) is used widely as a preservative in several products, including poultry feed. The anticoagulation effect of 200 mg/kg S-DHA in rats has been reported to accompany a reduction in hepatic expression of vitamin K epoxide reductase complex 1 (VKORC1). Poultry and mammals have different physiology and coagulation systems, and species differences in VKORC1 expression have been found. The effect of S-DHA on blood clotting of poultry has not been studies deeply. S-DHA was given to yellow-plumage broilers (YBs) as single and multiple administrations. Vitamin K3 (VK₃) was injected into YBs 2 wk after S-DHA administration. Then, the prothrombin time (PT), partial activated prothrombin time (APTT), plasma levels of vitamin K (VK), factor IX (FIX), and S-DHA, and hepatic expression of VKORC1 were obtained. Chicken hepatocellular carcinoma (LMH) cells were also exposed to S-DHA, and the cell activity, VK level, and FIX level were measured. S-DHA prolonged the PT or APTT significantly, decreased levels of VK and FIX in blood, and inhibited hepatic expression of VKORC1. The maximum changes were 1.15-fold in the PT, 1.42-fold in the APTT, 0.8-fold in the VK level, 0.7-fold in the FIX level, and 0.35-fold in VKORC1 expression compared with controls. The cell activity, VK level, FIX level, and VKORC1/VKORC1L1 expression of LMH cells were reduced significantly at S-DHA doses of 2.0 to 10.0 mM. Prolongation of the PT/APTT and lower levels of VK/FIX in YBs or the lower cell activity and VK/FIX levels in LMH cells induced by S-DHA therapy were resisted significantly by VK₃ treatment. We demonstrated that S-DHA could induce a disorder in coagulation function in YBs or in LMH cells via reduction of VKORC1/VKORC1L1 expression, and that VK could resist this anticoagulation effect.

Analysis of factors related to browning of red sour soup during fermentation

As a traditional fermentation food, red sour soup (RSS) is very popular in China. However, browning is always occurred during the process of fermentation, which influences the sensory quality of RSS and limits its further application. Thus, it is meaningful to elucidate the main factors related to browning during the process of fermentation. Herein, the changes in various factors related to browning from group spontaneous (RSS-SF) and inoculant fermentation (RSS-IF) were determined and analyzed. Firstly, the activity changes of enzymes related to browning indicated that browning of group RSS-SF and RSS-IF during fermentation was not related to enzymatic browning. Secondly, path analysis revealed that the main factors related to non-enzymatic browning of group RSS-SF and RSS-IF were oxidation of polyphenol and degradation of ascorbic acid (Vc). The results of this study not only identifies the main factors associate with browning of RSS, but also provides foundation on how to control the browning of RSS in further study.

Effect of Starters on Quality Characteristics of Hongsuantang, a Chinese Traditional Sour Soup

Hongsuantang (HST) is a traditional Chinese and famous sour soup. However, the quality of naturally fermented HST is not controllable. We investigated the effects of different lactic acid bacteria starters on HST acid production, color, antioxidant capacity, total phenols, total carotenoids, organic acids, volatile substances, and sensory properties to determine the most suitable strain for HST production. The results showed that among the seven lactic acid bacteria strains used to inoculate fermented HST, Lactiplantibacillus plantarum SQ-4 exhibited the most excellent fermentation characteristics. SQ-4 rapidly reduced the HST’s pH by 0.77. It significantly increased the HST’s color, organic acids, total phenols, carotenoids, lycopene, and free radical scavenging ability. Lactiplantibacillus plantarum SQ-4 was an excellent starter for preparing HST with good acid production capacity, moderate sourness and spiciness, and good sensory and other characteristics. Each starter produces its distinct flavor components. α-Pinene, myrcene, α-copaene, and guaiol were vital aroma compounds in HST fermentation by the starter. This study laid a foundation for selecting HST starters and potential industrial production.

The Correlation Mechanism between Dominant Bacteria and Primary Metabolites during Fermentation of Red Sour Soup

Chinese red sour soup is a traditional fermented product famous in the southwestern part of China owing to its distinguished sour and spicy flavor. In the present study, the effect of inoculation of lactic acid bacteria (LAB) on the microbial communities and metabolite contents of the Chinese red sour soup was investigated. Traditional red sour soup was made with tomato and red chilli pepper and a live count (108 CFU/mL) of five bacterial strains (including Clostridium intestinalis: Lacticaseibacillus rhamnosus: Lactiplantibacillus plantarum: Lacticaseibacillus casei: Lactobacillus paracei) was added and fermented for 30 days in an incubator at 37 °C. Three replicates were randomly taken at 0 d, 5 d, 10 d, 15 d, 20 d, 25 d and 30 d of fermentation, with a total of 21 sour soup samples. Metabolomic analysis and 16S-rDNA amplicon sequencing of soup samples were performed to determine microbial diversity and metabolite contents. Results revealed that fermentation resulted in the depletion of native bacterial strains as LAB dominated over other microbes, resulting in differences in the relative abundance of bacteria, and types or contents of metabolites. A decrease (p < 0.01) in Shannon and Simpson indices was observed at different fermentation times. The metabolomic analyses revealed a significant increase in the relative content of 10 metabolites (particularly lactic acid, thymine, and ascorbic acid) in fermented samples as compared to the control. The correlation network revealed a positive association of Lacticaseibacillus rhamnosus with differentially enriched metabolites including lactic acid, ascorbic acid, and chlorogenic acid, which can desirably contribute to the flavor and quality of the red sour soup.