Volatile aroma and physicochemical characteristics of freeze-dried coconut water using different encapsulating agents.

This research studied how different types and concentrations of encapsulating agents impacted freeze-dried coconut water products. Volatile aroma and physicochemical product characteristics were evaluated. The encapsulating agents were maltodextrin 4-8% (w/v), polydextrose 4-8% (w/v) and xanthan gum 0.1-0.3% (w/v). A plate freezer and an air blast freezer were used to pre-freeze the coconut water before drying. Freezing time had no impact on moisture content and water activity. The flavor compounds of coconut water is composed of alkanes, aldehyde, ketones, organic acids and some other flavor substances. Encapsulating agents are the main factors affecting the flavor of coconut water. Optimal conditions for producing dried coconut water were adding polydextrose at a concentration of 8%. Volatile compounds were assessed under different conditions of SPME- GC-TOFMS. The composition of flavor compounds in coconut water is complex and mainly includes esters, aldehydes, and phenols. Results showed that encapsulating agents improved the volatile aroma of dried coconut water products.

Novosphingobium kaempferiae sp. nov., a phosphate-solubilizing bacterium isolated from stem of Kaempferia marginata Carey.

A Gram-stain-negative, aerobic, rod-shaped, non-spore-forming and yellow-pigment-producing bacterium, designated as Sx8-5T, was isolated from stem tissue of Kaempferia marginata Carey in Kanchanaburi Province, Thailand. The strain exhibited tricalcium phosphate solubilizing activity. Its taxonomic position was investigated using a polyphasic approach. Sx8-5T grew at 25-37 °C (optimum 30 °C), pH 6-9 (optimum 7) and with 0 and 1% NaCl (optimum 0 %). According to the 16S rRNA gene phylogeny, Sx8-5T represents a member of genus Novosphingobium and shared the highest sequence similarities to Novosphingobium barchaimii LL02T of 99.4 % and shared sequence similarities with other species of the genus Novosphingobium of less than 99.4 %. The whole-genome size was 5.7 Mb, comprised of one contig, with a DNA G+C content of 66 %. The average nucleotide identity using BLASTn (ANIb) or MUMMER (ANIm) values for whole genome comparisons between Sx8-5T and Novosphingobium barchaimii LL02T and six closely related type strains were 72.33-82.14 % and 83.82-87.38 %, respectively, and the digital DNA-DNA hybridization (dDDH) values ranged from 21.0 to 28.6% when compared with the type strains of the members of the genus Novosphingobium. Major fatty acids were summed feature 8 (C18 : 1 ω7c and/or C18 : 1 ω6c), C16 : 0 and summed feature 3 (C16 : 1 ω7c and/or C16 : 1 ω6c), respectively. Polar lipids were diphosphatidylglycerol, phosphatidylethanolamine, phosphatidylmonomethylethanolamine, phosphatidylglycerol, unidentified phospholipids and unidentified polar lipids. The major isoprenoid quinone was Q-10. According to results obtained using a polyphasic approach, Sx8-5T represents a novel species of the genus Novosphingobium, the name Novosphingobium kaempferiae sp. nov. is proposed. The type strain is Sx8-5T (=JCM 35076T =TBRC 15600T).

In Vitro Antimicrobial Activity of Piper retrofractum Fruit Extracts against Microbial Pathogens Causing Infections in Human and Animals.

Long pepper (Piper retrofractum Vahl) is a Thai medicinal herb which has been used as one of the common ingredients in variety of Thai foods. Here, we investigated antimicrobial activities of crude bioactive metabolites extracted from fruits of P. retrofractum against 10 pathogenic organisms (bacteria and yeast) causing opportunistic infections in human or animals including Bacillus subtilis ATCC6633, Staphylococcus aureus ATCC25923, Enterococcus faecalis ATCC2921, Escherichia coli ATCC25922, Klebsiella pneumonia TISTR1843, Pseudomonas aeruginosa ATCC741, Salmonella typhi (clinical isolate), Vibrio parahaemolyticus (XN98 and 5HP), and Candida albicans ATCC90020. The results of disk diffusion test showed that the extract from methanol solvent exhibited greater antibacterial activity than other solvents with inhibition zones ranging from 0.5 to 8.0 mm, respectively. Subsequently, minimal inhibition concentration (MIC) determined by the colorimetric assay confirmed that methanol extracts showed consistent results with disk diffusion method. In summary, in vitro assays suggest that methanol is the best solvent for extraction of bioactive metabolites from P. retrofractum fruits. This crude extract can inhibit the majority of human and animal pathogens. This opens up a potential use of pepper fruits in prevention of food-contaminating microorganisms.