The present work aimed to search for a released peptide from proteolytic action on a silver barb fish muscular protein that confers health benefit through antioxidation activity. Changes in the physicochemical, microbiological, and protein characteristics of plaa-som samples during eight days of both spontaneous traditional fermentation (Batch 1; B1) and spontaneous fermentation with the addition of pineapple (Batch 2; B2) were determined. Results showed a correlation between an increase in the total acidity and bacterial counts with the length of fermentation duration, where the pH gradually decreased at the end of fermentation. Protein hydrolysis during fermentation was indicated by an increase in the amount of TCA-soluble peptide contents that peaked on day 5 (D5) in both batches (B1D5 and B2D5), which displayed their highest DPPH radical-scavenging inhibition of plaa-som protein hydrolysates (PSPHs). Twelve peptide fractions of the best PSPH were separated by ultrafiltration using molecular weight cut off (MWCO) at 3 and 10 kDa, and they were also purified by size exclusion chromatography. Results demonstrated that stronger peptides B2D5 - 3 kDa - F1 and B1D5 - 10 kDa - F1 were arranged in 12 peptides, which exhibited the highest reducing power, more than their radical-scavenging inhibition (p < 0.05). Therefore, it was concluded that both peptides obtained from PSPH have released antioxidative peptides that could be beneficial towards consumer's health, particularly the spontaneous plaa-som fermented with the addition of pineapple.

The development of functional food products is increasingly gaining lots of interest and popularity among stakeholders. The aim of this study was to evaluate the bioaccessibility of three Lactobacillus sp. starter cultures, including Lacticaseibacillus casei KKU-KK1, Lactiplantibacillus pentosus KKU-KK2, and Lactobacillus acidophilus KKU-KK3, in order to enhance the performance of the probiotic potential of Nham protein hydrolysates in Thai fermented sausage using microencapsulation technology. Probiotic microcapsules were created from a novel wall material made up of a combination of glutinous rice flour and inulin through a freeze-drying process. Accordingly, the results of three formulations of Nham probiotic and spontaneous fermentation (control) characterized by their physicochemical and microbiological characteristics displayed a correlation between an increase in the amount of total acidity, the population of lactic acid bacteria, and the generated TCA-soluble peptides, while the pH and total soluble protein gradually decreased under proteolysis during the fermentation time. The fractionation of Nham protein hydrolysates (NPHs) was prepared using a microwave extraction process: NPH-nham1, NPH-nham2, and NPH-nham3 (10 mg/mL with fermentation time 114 h), exhibited the highest DPPH radical-scavenging activity and FRAP-reducing power capacity as well, compared to NPH-nhamcontrol at p < 0.05. Moreover, those NPHs peptides showed dose-dependent inhibiting of selected pathogenic bacteria (E. coli TISTR 073, S. aureus TISTR 029, and Ent. aerogenes TISTR 1540). Anti-microbial properties of NPHs peptides against gram-negative bacteria were higher than against gram-positive bacteria. In conclusion, the bioaccessibility of NPHs peptides was significantly enhanced by micro-encapsulation and showed a potential bioactive characteristic for developing into a probiotic agent.