Changes in biogenic amines during the conventional production of stinky tofu

Microbial Community Succession and Its Correlation with Quality Characteristics during Gray Sufu Fermentation

Gray sufu, a traditional fermented food derived from soybeans, undergoes a complex fermentation process. This study aimed to investigate the dynamics of the microbial community during sufu fermentation and its relationship with key quality characteristics. Through systematic sampling of sufu at different phases of fermentation, 143 bacterial genera and 84 fungal genera involved in the process were identified. Among these, Chishuiella, Enterococcus, Lactococcus, and Weissella emerged as the predominant bacterial communities. After seven days of ripening fermentation, Trichosporon supplanted Diutina as the predominant fungus, accounting for more than 84% of all fungi. Using redundancy analysis, significant correlations between microbiota and physicochemical properties were uncovered. Chishuiella and Empedobacter displayed positive relationships with pH, soluble protein, and amino nitrogen content. In addition, five biogenic amines were detected, and it was determined that tyramine accounted for more than 75% of the total biogenic amines in the final gray sufu products. Spearman correlation analysis revealed significant positive relationships between Lactococcus, Enterococcus, Tetragenococcus, Halanaerobium, and Trichosporon and the five biogenic amines examined. These findings shed light on the complex interactions between microorganisms and biogenic amines during the fermentation of gray sufu, thereby facilitating the development of microbial regulation strategies for better quality control.

Effects of Physicochemical Characteristics and Storage Stability of Porcine Albumin Protein Hydrolysates in Pork Sausage

In this study, the physicochemical characteristics and storage stability of porcine albumin protein hydrolysates (PAPH) in sausage were evaluated. Four concentrations of PAPH were added to pork emulsion sausage (T1, 0.3%; T2, 0.6%; T3, 0.9%; T4, 1.2%) and compared to the control (CON, 0%). On day 0, proximate composition, cooking loss, and sensory evaluation were compared. Purge loss, color, texture profile analysis, shear force, free amino acids, lipid oxidation, microbial counts, and volatile basic nitrogen (VBN) were compared on day 0 and after 4 weeks of refrigeration. The content of essential amino acids and redness(a*) increased as the level of PAPH added increased (p<0.05). Also, the cooking loss was improved (p<0.05). However, lipid oxidation, microbial counts, and VBN were increased significantly during storage for 4 weeks (p<0.05). The findings indicated that the addition of PAPH improved cooking loss and the protein composition of sausages, but negatively affected storage stability.

Process improvement to prevent the formation of biogenic amines during soy sauce brewing

Biogenic amines (BAs) are a class of bioactive organics produced during the fermentation of soy sauce. A high concentration of BAs may bring about serious physiological and toxicological effects on the human body. In this study, we reported an optimized process to produce soy sauce with lower BA concentration and found the contents of putrescine, cadaverine and histamine increased with the increase of fermentation temperature but decreased with the increase of NaCl concentration. The final content of total BAs with improved fermentation was 105.56 ± 0.13 mg/L, which was reduced by 89.11% compared to traditional brewing. Besides, the pilot production test was performed to verify the optimized conditions and physicochemical indexes were measured to better understand the change principle of the chemical compounds. Taken together, we present an effective process to inhibit the formation of BAs while ensuring that characteristic nutrients are not lost.

Effects of different strains and fermentation method on nattokinase activity, biogenic amines, and sensory characteristics of natto

Nattokinase activity (NK), biogenic amine content and sensory properties of natto are of great significance to consumers, which are affected by strains and fermentation methods. In this study, changes in the pH, biogenic amine and free amino nitrogen (FAN) contents, NK and protease activities, and sensory characteristics of natto prepared using Bacillus subtilis GUTU09 combined with different strains (Lactobacillus, Bifidobacterium and Mucor) and fermentation methods were investigated. The combination of two strains showed the best fermentation performance among all samples. The NK and protease activity and FAN content in double-strain fermentation increased by 10.33 FU/g, 88.78 U/g, and 2.34 g/kg, respectively, compared with those in single-strain fermentation. Sensory evaluation demonstrated that mixed fermentation primarily affected the sensory acceptance. This method also reduced the contents of various biogenic amines in natto compared with single-strain fermentation. Tyramine, cadaverine, spermine, and spermidine were significantly reduced, whereas histamine was slightly increased. The total biogenic amines decreased from 390.76 mg/kg to a minimum of 16.16 mg/kg. Some Mucor strains also reduced the contents of various biogenic amines. In the dual-bacteria fermentation of Mucor and GUTU09, co-fermentation has advantages over stage-fermentation, with higher NK and protease activity and higher sensory scores. Correlation analysis showed that the formation and accumulation of some biogenic amines in natto prepared using different microbial combinations were related to NK activity and pH. All these results showed that the quality of natto was improved by mixed fermentation and suitable fermentation methods, which laid a foundation for its potential industrial application.

Bacterial Production and Control of Biogenic Amines in Asian Fermented Soybean Foods

Fermented soybean foods possess significant health-promoting effects and are consumed worldwide, especially within Asia, but less attention has been paid to the safety of the foods. Since fermented soybean foods contain abundant amino acids and biogenic amine-producing microorganisms, it is necessary to understand the presence of biogenic amines in the foods. The amounts of biogenic amines in most products have been reported to be within safe levels. Conversely, certain products contain vasoactive biogenic amines greater than toxic levels. Nonetheless, government legislation regulating biogenic amines in fermented soybean foods is not found throughout the world. Therefore, it is necessary to provide strategies to reduce biogenic amine formation in the foods. Alongside numerous existing intervention methods, the use of Bacillus starter cultures capable of degrading and/or incapable of producing biogenic amines has been proposed as a guaranteed way to reduce biogenic amines in fermented soybean foods, considering that Bacillus species have been known as fermenting microorganisms responsible for biogenic amine formation in the foods. Molecular genetic studies of Bacillus genes involved in the formation and degradation of biogenic amines would be helpful in selecting starter cultures. This review summarizes the presence and control strategies of biogenic amines in fermented soybean foods.

Biogenic amines content in the fermented asian food in the Czech Republic

The aim of this work was to study the typical fermented Asian food (miso paste, soy sauce, rice vinegar, kimchi and tempeh) to monitor their microbial quality and presence of biogenic amines in relation to time and temperature of storage. This study is focused on microbiological research in order to determinate presence of selected indicator groups of microorganisms during storage of individual products at three different temperatures, 8 °C, 23 °C, 30 °C. It was found that the highest increase of total viable counts was observed in products stored in 23 °C and 30 °C, especially in tempeh and miso paste. In soy sauce and rice vinegar were observed only very low amounts of microorganisms through the storage period. In the second part of the experiment, the biogenic amines were analyzed using high performance liquid chromatography. It was found that the levels of biogenic amines in tested products were low and does not affect human health.

Reduction of biogenic amines in sufu by ethanol addition during ripening stage

The aim of this study was to investigate the content of biogenic amines (BAs) in different types of sufu samples obtained from different producers, and the effect of ethanol in reducing BA levels during sufu ripening. The results showed that different manufacturing processes altered the distribution of BAs in commercial sufu. Putrescine, cadaverine, histamine, and tryptamine were the main and common BAs in red, white and grey sufu. The contents of putrescine, cadaverine, tryptamine, β-phenylethylamine and tyramine in the grey sufu of all producer brands were significantly (p<0.05) higher than those in the white and red sufu. The addition of ethanol to the dressing mixture had a significant influence in reducing the total content of BAs in laboratory-made sufu. The slight increase in polypeptide and amino nitrogen contents after the addition of ethanol indicated a reduction in the degradation of water soluble protein.

Biologically active amines in fermented and non-fermented commercial soybean products from the Spanish market

Biologically active amines were determined in commercial soybean products. The antioxidant polyamines were found in both non-fermented and fermented soybean products. Natto and tempeh showed the highest content of polyamines (75-124 and 11-24 mg/kg of spermidine and spermine, respectively). On the other hand, the bacterial-related biogenic amines, tyramine, histamine, tryptamine and β-phenylethylamine, were detected in practically all fermented products with a high variability. The highest contents were found in sufu, tamari and soybean paste. Extremely high tyramine and histamine contents, 1700 and 700 mg/kg, respectively, found in some sufu samples could be unhealthy. However, biogenic amines observed in the other soybean products should not be a risk for healthy consumers. However, individuals who take monoamine and diamine oxidase inhibitors drugs should be strongly recommended to avoid this kind of products in order to suffer no adverse health effects. These biogenic amines were not detected in non-fermented soybean products.

Trans- and cis-urocanic acid, biogenic amine and amino acid contents in ikan pekasam (fermented fish) produced from Javanese carp (Puntius gonionotus) and black tilapia (Oreochromis mossambicus)

Ikan pekasam is a fermented fish product produced in Malaysia and is usually made from freshwater fish with ground roasted uncooked rice as the main source of carbohydrate. In this study, the amino acid, biogenic amine, and trans- and cis-urocanic acid (UCA) contents of fifteen commercial samples of Ikan pekasam made from Javanese carp and black tilapia, that had undergone either natural or acid-assisted fermentation, were quantified. The latter includes either tamarind (Tamarindus indica) pulp or dried slices of Garcinia atroviridis fruit in the fermentation process. Results showed that there are no significant differences in most of the biogenic amines including histamine, while there are significant differences in total UCA content, and trans- and cis-UCA contents between the two samples. Differences in the amino acid contents were largely fish-dependent.

Changes in urocanic acid, histamine, putrescine and cadaverine levels in Indian mackerel (Rastrelliger kanagurta) during storage at different temperatures

Histamine, putrescine cadaverine and cis-urocanic acid (UCA) have all been implicated or suggested in scombroid fish poisoning. However, there is little information on UCA especially during storage. Changes in their contents during storage of whole Indian mackerel at 0, 3±1, 10±1 for up to 15 days and 23±2°C for up to 2 days were monitored. Fresh muscles contained 14.83 mg/kg trans-UCA, 2.23 mg/kg cis-UCA and 1.86 mg/kg cadaverine. Histamine and putrescine were not detected. After 15 days at 0 and 3°C, trans-UCA content increased to 52.83 and 189.51 mg/kg, respectively, and decreased to <2 mg/kg at the other two temperatures. Storage at 10°C also resulted in an increase in trans-UCA after 3 days, only to decrease after 6 days. The concentration of cis-UCA increased nearly 13-fold after 15 days at 0 and 3°C, decreased at 10°C and remained unchanged at 23°C. Histamine, putrescine and cadaverine levels increased significantly (P value<0.05) at all temperatures especially at 23°C.