RESUMEN
Mollusca species shell such as oyster shell (OS) and snail shell (SS), are discarded after taking the meat, and the discarded shell causes the environmental problems. Therefore, recycling shell waste could potentially eliminate the environmental problems. This study aimed to evaluate the potential of OS and SS as natural calcium resources. The minerals, calcium, magnesium, potassium, phosphorus and sodium were analyzed in OS and SS extracts. Among them, the calcium content was the highest: 36.87 (%) and 33.42 (%) in the OS and SS extracts, respectively. Further, the content of ionized bioavailable form of calcium in OS and SS was higher than that of CaCO3 under simulated gastrointestinal digestion conditions. Additionally, OS and SS were added to kimchi, and their inhibitory effect on kimchi acidification was evaluated by assessing pH, titratable acidity and microbial analysis. As the results indicated that the addition of OS and SS had little effect on inhibiting the growth of lactic acid bacteria. However, it was confirmed that calcium neutralizes the organic acids produced during fermentation. Overall, the results of this study provide preliminary information on the re-use of OS and SS extracts as ionized natural calcium supplements and fermentation retardants.
RESUMEN
The taste of kimchi is greatly affected by the salt type used during fermentation. Here, we investigated the effects of salts with different mineral contents on the microbial community and metabolite profiles of fermented kimchi using multivariate statistical analysis. We evaluated different types of salt used to prepare kimchi, namely, solar salt aged for 1 year, solar salt aged for 3 years, dehydrated solar salt, and purified salt. The main microorganisms detected in kimchi were Weissella koreensis, Leuconostoc mesenteroides, and Latilactobacillus sakei. Leuconostoc and Weissella were mainly present in kimchi supplemented with solar salt. However, a high proportion of L. sakei was present in kimchi supplemented with purified salt and dehydrated salt. Additionally, using GC-MS-based metabolite analysis, we revealed that the content of free sugars, organic acids, and amino acids differed in kimchi fermented with different salt types. Therefore, we demonstrated that salt type had a pronounced effect on the resultant microbial community and the type and concentration of metabolites present in fermented kimchi.
RESUMEN
Moringa oleifera leaf (ML) is rich in vitamins and minerals, specially abundant calcium, therefore it is widely used as a calcium supplement for food. This study aimed to investigate the antioxidant activity and calcium bioaccessibility of M. oleifera leaf hydrolysate (MLH) as a calcium supplement for kimchi. MLH was prepared under three different proteases, two different protease contents, and three different incubation times. Total phenol content (TPC), total flavonoid content (TFC), and antioxidant activities were investigated. Cellular activity and calcium bioaccessibility were also investigated. The highest calcium level of MLH was observed in 3% Protamex treatment for 4 h. TPC, TFC, and antioxidant activities of MLH in Protamex and Alcalase treatments were higher than those in Flavourzyme treatment (p < 0.05). Moreover, high cell viability and alkaline phosphatase activity were also observed in C2C12 cells. Kimchi containing MLH showed high calcium accessibility compared to kimchi alone. Taken together, the application of MLH could have potential as a calcium supplement for kimchi production.