Optimized supercritical CO2 extraction conditions on yield and quality of torch ginger (Etlingera elatior (Jack) R.M. Smith) inflorescence essential oil

Natural preservatives derived from plant sources have been actively studied as an alternative to synthetic materials. Various extraction methods had been done to utilize the torch ginger plant for food, nutraceutical and pharmaceutical applications. Supercritical carbon dioxide (SC−CO2) extraction is a sustainable green technology to extract high-purity oil with high aromatic compound content. This study aims to optimize the SC−CO2 extraction conditions on high yield and strong antioxidant activity of torch ginger (Etlingera elatior) inflorescence essential oil (TGIEO). Response surface methodology in combination with central composite design was employed and two independent variables, pressure (83.6–366.4 bar) and temperature (34.7–57.3 °C) were analysed to optimize the response variables. Pressure was observed as the most significant parameter affecting the yield and antioxidant activity. The optimized SC−CO2 extraction conditions were pressure 286.4 bar and temperature 57.3 °C. The experimental values of response variables at these SC−CO2 extraction conditions match well with the predicted values which confirm the model validity. The TGIEO showed high diphenyl-2-picryl-hydrazyl and 2,2′-azino-bis (3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt radical scavenging activity. Antimicrobial activity screening for TGIEO was done via disc diffusion assay and showed inhibition zone (11.5 ± 0.71 to 22.0 ± 2.83 mm) against six pathogenic bacteria (Bacillus subtilis, Staphylococcus aureus, Listeria monocytogenes, Salmonella typhi, Vibrio species and Escherichia coli). Listeria monocytogenes was observed as the most sensitive microorganism with minimal inhibitory concentration (0.16 mg/mL) and minimal bactericidal concentration (0.63 mg/mL) respectively. Compounds 1-dodecanol and lauryl acetate were identified as major constituent in TGIEO

Development, characterization and in vivo antibacterial and antioxcidant study of a coconut milk-based kefir beverage

Kefir, a fermented beverage traditionally produced from cow's milk using kefir grains, faces challenges due to the global shift away from dairy products driven by concerns such as lactose intolerance, milk allergies, and environmental impacts. To address this, the present study was undertaken to develop a plant-based alternative – coconut milk kefir. This research aims to explore the effect of fat content on the physicochemical, nutritional, and biochemical characteristics of Reduced Fat Coconut Milk Kefir (RFCMK) and High Fat Coconut Milk Kefir (HFCMK), optimize the pH, antibacterial, and antioxidant properties of coconut milk kefir, evaluate its biochemical, metabolomic, sensory attributes, and shelf life, and assess its in vivo antibacterial and antioxidant effects. In the investigation of fat content's influence on beverage properties, RFCMK exhibited higher lactic acid bacteria (LAB) growth and superior antibacterial activity against Bacillus subtilis (94.62±2.46%), Staphylococcus aureus (96.82±0.8%), Escherichia coli (100±1.63%), and Salmonella Typhimurium (98.67±1.37%) through antibacterial inhibitory tests. Furthermore, RFCMK demonstrated significantly elevated levels of DPPH, ABTS, and FRAP compared to HFCMK. Remarkably, through Response Surface Methodology (RSM), an optimal formulation was achieved solely by adjusting fermentation parameters, resulting in high antimicrobial activity (93.1 – 100%) against various pathogens and robust antioxidant properties (DPPH: 72.6%, ABTS: 47.06%, FRAP: 437.045 μM TE/100 mL). Metabolomic analysis using 1H–NMR revealed significant changes in metabolites like lactic acid, GABA, Biotin, Riboflavin, Butyrate, and Caprylate during fermentation, known to enhance antioxidant status and reduce lipid peroxidation. LC-MS/MS (Q-TOF) also identified 11 bioactive peptides with antibacterial properties. Consumer acceptability comparisons between cow's milk and coconut milk kefir showed no significant difference between the two products based on a 9-point hedonic scale. During a 30-day storage period at 4°C, syneresis significantly increased after day 15, accompanied by a gradual rise in acidity, reaching pH 3.5 by day 17. The microbial count of LAB and yeast dropped below the Codex Alimentarius Commission recommended values of 7.00 and 4.00 Log CFU/mL after days 17 and 14, respectively. In vivo assessment of the optimized coconut milk kefir in Wistar rats revealed increased LAB levels in the cecum, reduced Alkaline Phosphatase (ALP) and Aspartate Transferase (AST) levels, elevated High-Density Lipoprotein (HDL) levels in the blood, and heightened Total Superoxide Dismutase (T-SOD) levels in the liver. In conclusion, this study highlights the potential of coconut milk kefir as a healthy, plant- based alternative to traditional dairy kefir. Its diverse benefits include improved antibacterial and antioxidant properties, appealing sensory characteristics, and positive in vivo health effects, offering a promising option for those seeking dairy-free fermented beverages

Biological activities and physiochemical properties of low-fat and high-fat coconut-based kefir

Coconut milk is a rich source of several nutrients and free of lactose which can be an excellent alternative to cow milk for lactose-intolerant consumers. This study aimed to investigate the potential of producing coconut-based kefir beverages using low-fat and high-fat coconut milk. The beverage was evaluated for pH values, titratable acidity, peptide content, antibacterial activity, antioxidant activity, and rheological properties. The results showed a significant increase in lactic acid bacteria and yeast after the fermentation for 24 h. The pH of the low-fat and high-fat coconut milk kefir declined to 3.77 ± 0.01 and 3.84 ± 0.01, respectively. The titratable acidity increased to 0.75 ± 0.04% and 0.66 ± 0.01% lactic acid, respectively. The fermentation with kefir grains significantly increased the peptides content of low-fat coconut milk to 0.7 ± 0.016 mg mL−1, and for high-fat coconut milk, it increased to 0.571 ± 0.038 mg mL−1. In addition, low-fat coconut kefir showed strong antibacterial growth inhibition and antioxidant activity. The apparent viscosity of the kefir beverage decreased with increasing shear rate and was higher at a lower temperature. The low-fat coconut kefir's flow behavior index (n) and consistency index (K) were 0.216 and 0.223. The consistency index (K) was 3.067 and 0.576 Pa s n at 5 and 25 °C, respectively. Moreover, the (n) values of high-fat coconut kefir were recorded as 0.422 and 0.581, and (K) values as 0.33 and 1.245 Pa s n. Therefore, low-fat coconut milk can be an alternative to cow milk in producing kefir-based beverages

Physical properties, storage stability, and consumer acceptability for sourdough bread produced using encapsulated kombucha sourdough starter culture

This study aimed to produce sourdough bread using an encapsulated kombucha sourdough starter culture without the addition of baker's yeast. The bioactive metabolites of kombucha sourdough starter and sourdough starter without kombucha were identified using 1H-NMR analysis with multivariate analysis. The physical properties, including loaf volume, specific loaf volume, firmness, and water activity were determined following standard methods. The shelf life and consumer acceptability of the bread were also being evaluated. The principal component analyses showed the presence of 15 metabolites in kombucha sourdough starter. The major compounds that contributed to the differences from sourdough starter without kombucha were alpha-aminobutyric acid, alanine, acetic acid, riboflavin, pyridoxine, anserine, tryptophan, gluconic acid, and trehalose. The encapsulated kombucha sourdough starter increased the loaf volume (976.7 ± 25.2 mL) and specific loaf volume (4.38 ± 0.12 mL/g) compared to yeast bread. Thus, significant (P < 0.05) reduction was observed in the crumb firmness (116.07 ± 6.28 g) compared to traditional sourdough bread and yeast bread. The encapsulated kombucha sourdough starter extended the shelf life of bread by 5 to 10 days at room temperature. The sourdough bread prepared using the encapsulated kombucha sourdough starter demonstrated significantly (P < 0.05) higher taste and overall acceptability scores compared to the other bread. The findings indicate that the encapsulated kombucha sourdough starter is promising to produce functional sourdough bread with extended shelf life and improved quality