Emulsifying properties of β-glucan-rich extracts obtained from Pleurotus ostreatus whole mushroom and stipes

In this work, aqueous fractions were extracted from the whole Pleurotus ostreatus biomass (AF) and from a waste product (RAF) generated from it in the industry (stipes) with the aim of valorizing them as emulsifying ingredients. The composition of the aqueous extracts, before and after a purification step (p) carried out to enrich its content in β-glucans, was correlated with the physical stability, rheological properties and microstructure of oil-in-water (O/W) emulsions. Better emulsifying properties were obtained for AFp-based emulsions (being able to incorporate greater amounts of oil phase), than for emulsions formulated with non-purified fractions. These properties can be attributed to the relatively high protein content of AFp fractions (acting at the O/W interphase) and high viscosity of the continuous phase which slowed down the oil droplet movement. The lower emulsifying properties of β-glucan extracts obtained from the stipes was ascribed to the lower content of proteins, which were less accessible to act as surface-active compounds due to the greater glucan structural complexity with which they are interacting.