Investigation on β-D-glucan extraction methods from Pleurotus ostreatus mycelium and its capability to adsorb aflatoxin M1 in milk

Milk and dairy products constitute a critical component of the human diet, particularly for children. Nevertheless, the presence of aflatoxins, such as aflatoxin M1 (AFM1), within milk is highly undesirable due to their associated health risks. It is imperative to employ safe methodologies to reduce or eliminate aflatoxins from milk exceeding permissible standards. A promising novel approach involves the utilization of organic absorbent compounds. Structural beta-D-glucan, a constituent of the fungal cell wall of organisms like the oyster mushroom (Pleurotus ostreatus), emerges as a potential organic adsorbent. This study encompassed the collection, drying, and pulverization of mycelial biomass cultivated in a laboratory setting. Diverse extraction techniques, including hot water, acid, and hot alkali treatments or ultrasonic pretreatment, were applied to isolate polysaccharide compounds, including beta-D-glucan, from the fungal mycelium cell wall. The beta-D-glucan content yielded by each extraction method was quantified using the Megazyme Assay Kit. Results indicated that the hot alkali method demonstrated superior beta-D-glucan extraction efficiency at 77.54% compared to alternative approaches. To assess the AFM1 adsorption capacity of extracted beta-D-glucan, a specific quantity (2.5 mg/ml) was added to milk which was artificially contaminated with varying AFM1 concentrations. Subsequently, adsorption efficiency was determined via High-Performance Liquid Chromatography (HPLC). Findings revealed that the addition of extracted beta-D-glucan resulted in the adsorption of up to 100%, 70%, and 58% of AFM1 content within contaminated milk at concentrations of 35, 75, and 120 ng/L, respectively, within 10, 20, and 40 min. These research outcomes introduce a secure and organic adsorbent capable of removing or reducing AFM1 in contaminated milk, thereby fostering public health confidence. Moreover, beta-D-glucan not only lacks the adverse effects associated with chemical compounds but also offers potential additional benefits when retained within the milk.