Response Surface Optimization of Crude Polysaccharides from Grey Oyster Mushroom (Pleurotus sajor-caju (Fr.) Singer) Using Pressurized Hot Water Extraction

Abstract

: Grey oyster mushroom ( Pleurotus sajor-caju (Fr.) Singer) is a popular edible mushroom in Thailand due to its high nutritional and medicinal benefits. This study aims to study the effects of temperature (100–140 °C), pressure (4–7 bar), and extraction time (20–60 min) on the extraction crude polysaccharides with environmentally friendly pressurized hot water. The extraction condition was optimized by the maximize yield using response surface method based on a central composite design (CCD). The temperature was the main effect on the increase of extracted yield. The optimum extraction condition was 140 °C, 10 bar, and 26.79 min with a corresponding yield of 31.31 ± 2.55%. Under these conditions, the total phenolic content of crude polysaccharides was 401 ± 8.24 mg GAE/g dry mushroom. In addition, the total glucan content was indicated as 34.50 ±1.79 g/100 g dry mushroom, which separated as 32.47 ± 1.95 mg/100 g of β -glucans and 2.04 ± 0.98 mg/100 g of 