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From Thai fermented fish sauce (Nam-pla), 59 bacterial isolates of halophilic glutaminase-producing bacteria were isolated. The hydrolysis of glutamine served as the primary screening procedure. It was discovered that strain FF5302 was an influential producer of the extracellular halophilic glutaminase enzyme. The moderately halophilic bacterium Tetragenoccus muriaticus FF5302 was identified through sequence analysis of the 16S rRNA gene, phylogenetic tree analysis, and phenotypic identification before it was possible to determine the optimal nutritional and culture conditions for its halophilic glutaminase activity. The purpose of this research was to determine the optimal nutritional and cultural conditions for producing halophilic glutaminase activity in a stirred tank bioreactor with a volume capacity of 3 L. The production of halophilic glutaminase from strain FF5302 was investigated by optimizing various physicochemical parameters. Seven potential factors are generally considered in halophilic glutaminase production, namely NaCl concentration, initial pH, temperature, incubation time, nitrogen sources, carbon sources, and inoculum size. According to the findings, the amount of halophilic glutaminase in the inoculum had an effect on the growth and activity of the enzyme when it was present at a concentration of 5 % (v/v). It was also found that halophilic glutaminase showed the highest activity (87.4 U mL−1) of strain FF5302 in SGC liquid medium containing NaCl 20 % (w/v), pH 8.0, agitation at 200 rpm, and an aeration rate of 0.05 VVM at 37 °C for 120 h. The size of the inoculum influenced both the proliferation and activity of halophilic glutaminase in the inoculum. Consequently, T. muriaticus FF5302 possessed an exceptional capacity to synthesize halophilic glutaminase. Furthermore, the halophilic glutaminase enzyme from halophilic bacteria is a prospective option for usage in the food industry as an aroma and flavor enhancer. HIGHLIGHTS muriaticus FF5302 was exceptionally capable of producing halophilic glutaminase. In addition, the enzyme is a viable candidate for usage in the food industry as an aroma and flavor enhancer. Furthermore, this study could also be helpful and valuable in improving enzyme productivity at the bioreactor scale for various industrial applications. GRAPHICAL ABSTRACT

Sea lettuce (Ulva rigida) is an underutilized green macroalga. Scant knowledge and understanding exist regarding the optimal processing technologies to maximize seaweed nutrition. Pretreatment of sea lettuce before drying, either by blanching or steaming, induced diverse physical and biological property changes. Greenness increased, while lightness of the-sea lettuce reduced. Both drying processes reduced textural parameters and impacted sea lettuce bioactivity, with increased antioxidant capacity and phenolic compound content. Steaming followed by oven drying at 60 °C for 2.30 h maintained bioactivities during 4 months of storage. Food processing increased the ease of consumption and also maintained the nutritional value of the sea lettuce, thereby promoting the utilization of this seaweed as a beneficial food ingredient.

Rhododendron arboreum Sm. has wide applications in food and beverage, medicines, and cosmetics because the plant contains bioactive phytochemical components. In Thailand, other than for horticultural purposes, scant literature describes the potential applications of this Rhododendron species. Phytochemical composition, biological activity, and cell cytotoxicity of R. arboreum Sm. flower petal and leaf extracts were determined. Ethanolic extracts of fresh and dried flower petals (FF and DF, respectively) and dried leaves (DL) of R. arboreum were prepared by maceration with 60% ethanol for 7 days. Extraction yields of both FF and DF were higher than DL (19.22, 16.76, and 8.50% for FF, DF, and DL, respectively). Preliminary qualitative phytochemical screening showed different compositions in diverse plant parts. Saponins and tannins were present in every extract, with anthraquinones detected only in flowers and terpenoids only in leaves. Total phenolic (TPC) and flavonoid contents (TFC) were highest in DL (405.21 mg gallic acid equivalent and 127.30 mg catechin equivalent per g of dry extract, respectively), followed by DF and FF. Antioxidant properties were determined using two radical scavenging assays as 2,2-diphenyl-1-picrylhydrazyl (DPPH) and 2,2-azinobis(3-ethyl-benzthiazoline-6-sulfonic acid (ABTS). Results indicated that all extracts exhibited better inhibitory activity against DPPH radical than ABTS radical as evidenced by lower IC50 range 24.65-48.15 ìg/mL for DPPH and 65.19-76.36 ìg/mL for ABTS, respectively. A positive correlation coefficient between the two antioxidant assays and TPC and TFC of Rhododendron extracts indicated antioxidant potential distributed in both components. No cytotoxicity was recorded in the three extracts, with concentrations less than 500 μg/mL for both 3-(4,5-dimethylthiazol-2yl)-2,5-diphenyltetrazolium bromide (MTT) and CellTiter-Blue® assay. In vitro studiesexhibited dose-dependent and strong anti-melanogenic and anti-inflammatory activities ranging from 50 to 250 μg/mL for FF, DF, and DL. Results identified various bioactive constituents with potential biological activity (antioxidant, antiinflammatory, and anti-melanogenic), while non-cytotoxicity in R. arboreum flower and leaf extracts suggested the possibility of further applications as a functional ingredient in cosmetics.