Optimization of Plasma Activated Water Extraction of Pleurotus ostreatus Polysaccharides on Its Physiochemical and Biological Activity Using Response Surface Methodology.

This study focused on optimizing the extraction of P. ostreatus polysaccharides (POPs) using plasma-activated water (PAW). A single factor and response surface methodology were employed to optimize and evaluate the polysaccharide yield, physiochemical characteristics, and biological activities of POPs. The observed findings were compared to those obtained by the conventional hot water extraction method (100 °C, 3 h), as the control treatment. The optimal extraction conditions were obtained at 700 W PAW power, 58 s treatment time, 1:19 sample-to-water ratio, and 15 L/min gas flow rate. In these conditions, the PAW-treated samples experienced changes in surface morphology due to plasma etching, leading to a 288% increase in the polysaccharide yield (11.67%) compared to the control sample (3.01%). Furthermore, the PAW-treated sample exhibited superior performance in terms of biological activities, namely phenolic compounds (53.79 mg GAE/100 g), DPPH scavenging activity (72.77%), and OH scavenging activity (65.03%), which were 29%, 18%, and 38% higher than those of control sample, respectively. The results highlighted the importance of process optimization and provided new evidence for PAW as an alternative approach to enhance the extraction efficiency of POPs, a novel source of natural antioxidants which enables diverse applications in the food industry.

Characteristics and Antioxidant Activity of Fucoidan from Sargassum hystrix: Effect of Extraction Method.

Fucoidan is a bioactive compound of brown seaweed with antioxidant characteristics. This study examined the aftermath of the extraction method on the yield, fucose content, xylose content, sulfate content, total sugar, antioxidant activity, and functional groups of fucoidan from Sargassum hystrix. The brown seaweed was extracted using 4 methods, namely, A (0.1 N HCl, room temperature, 24 h), B (2% CaCl2, 85°C, 4 h), C (85% ethanol, room temperature, 12 h), and D (0.5% EDTA, 70°C, 3 h). The antioxidant activity testing was carried out using the 2,2-diphenyl-1-picrylhydrazyl (DPPH), Ferric-Reducing Antioxidant Power (FRAP), and Hydroxyl Radical Scavenging Activity (HRSA). The yield for methods of A, B, C, and D was 2.46 ± 0.30, 0.68 ± 0.34, 1.18 ± 0.15, and 0.62 ± 0.25%, with fucose content of 39.97 ± 4.82, 26.72 ± 3.38, 41.08 ± 9.49, and 40.62 ± 8.59%, xylose content of 8.07 ± 0.92, 5.63 ± 0.40, 6.80 ± 0.83, and 7.83 ± 1.83%, and the sulfate content of 11.47 ± 2.20, 15.31 ± 2.47, 30.62 ± 2.76, and 27.80 ± 3.59%. The result indicated the occurrence of a sulfate ester group in the functional group analysis with numerous similarities with the commercial fucoidan. The highest antioxidant activity of fucoidan from S. hystrix was found in method C, which was influenced by sulfate levels. Therefore, the extraction method of fucoidan from S. hystrix affects the characteristics and antioxidant activity.