Proteolytic enzymes play an important role in determining the quality of blue crab during postmortem storage. Activity of endogenous proteases is involved in the texture softening and autolysis of blue crab, which limits the customer acceptance and marketing price. This research aimed to characterize the protease activity of crude enzyme extract from the hepatopancreas of blue crab. The optimum activity of crude protease extract was found at pH 7.0 and 50°C. The crude protease enzyme was highly stable over a wide pH range of 4.0-11.0 and showed high stability at temperatures below 40°C. In addition, the protease activity continuously decreased with an increasing concentration of NaCl (0-15% w/v). Therefore, an understanding of the endogenous proteases in the blue crab could be used to develop appropriate storage methods during its distribution process.
Fermented fishery food products have been generally sold in the local market, Thailand. These products were frequently contaminated with various microorganisms due to raw material and unhygienic production process. Determination of microbial contamination of fermented food products helps to assure safety for consumers. Therefore, the aims of the study were to determine total bacteria, total coliform, Escherichia coli and histamine producing bacteria from fermented fishery food products commercially distributed in several regions of Chumphon and Surat Thani provinces. Twenty-two samples of fermented fishery food products were randomly collected for bacterial contamination assay. All samples revealed the levels of pH and salt content in the range of 3.67-7.46 and 8.46%-29.69%, respectively. The bacterial contamination of the samples was tested by total plate count method. Determination of coliform bacteria and E. coli was examined by multiple-tube fermentation technique. Total bacteria, total coliform and E. coli of all samples were in the range of 2.15-7.54 log CFU/g, < 3-460 MPN/g and < 3-93 MPN/g, respectively. In addition, thirteen histamine-forming bacteria were found on histamine-forming bacteria isolation agar after incubation at 37°C for 4 days. Five isolates of histamine-forming bacteria named M1, M3, M9, M11, and M13 were selected to identify by molecular techniques. M1 and M3 were obtained from shrimp paste (Kapi) and M11 was obtained from fermented fish (Pla Pang Dang). They were identified as Enterobacter sp. M9 and M13 isolated from fermented fish (Pla Som and Pla Ra) were identified as Citrobacter farmeri and Staphylococcus kloosii, respectively.
Rastrelliger brachysoma (short mackerel) and Rastrelliger kanagurta (Indian mackerel) are commercially important marine species in Southeast Asia. In recent years, numbers of these two species have been decreasing in the wild, and genomic information about them is still limited. We conducted a genome survey of these two mackerel species to acquire essential genomic information using next-generation sequencing data. To obtain this genetic information, comprehensive bioinformatics analyses were performed, including de novo assembly, gene prediction, functional annotation, and phylogenetic analysis. The estimated genome sizes were around 680.14 Mbp (R. brachysoma) and 688.82 Mbp (R. kanagurta). The heterozygosity of these species was very similar (≈0.81), while the repeat content for R. kanagurta (9.30%) was slightly higher than for R. brachysoma (8.30%). Functional annotation indicated that most of the genes predicted in these two species shared very close average amino acid identities (94.06%). The phylogenetic analysis revealed close phylogenetic relationships between these two species and other scombrids. This is the first reported genome survey and assembly of species in the genus Rastrelliger and could be useful for future comparative genomic studies.
scite is a Brooklyn-based organization that helps researchers better discover and understand research articles through Smart Citations–citations that display the context of the citation and describe whether the article provides supporting or contrasting evidence. scite is used by students and researchers from around the world and is funded in part by the National Science Foundation and the National Institute on Drug Abuse of the National Institutes of Health.
hi@scite.ai
10624 S. Eastern Ave., Ste. A-614
Henderson, NV 89052, USA
Copyright © 2024 scite LLC. All rights reserved.
Made with 💙 for researchers
Part of the Research Solutions Family.