EFFECT OF DRYING TEMPERATURE ON THE RELATIVE FATTY ACID PROFILE, GLUCAN FRACTIONS AND FATTY ACID-DERIVED LIPID QUALITY INDICES IN WILD-GROWING BAY BOLETE MUSHROOM (IMLERIA BADIA)

Abstract

This study evaluated the effect of drying temperature on the relative fatty acid profile, glucan fractions, and fatty acid profile-derived indices in wild-growing bay bolete mushroom (Imleria badia). Fruiting bodies collected in western Slovakia were processed as lyophilized reference material or dried by hot-air drying at 20, 30, 40, and 50 °C. Fatty acid methyl esters were determined by GC-FID, while total, α-, and β-glucans were quantified using the Megazyme enzymatic assay. Across all treatments, the fatty acid profile was dominated by linoleic acid (C18:2 cis-9, cis-12; 60.5–65.8%), followed by oleic acid (C18:1 cis-9; 15.3–18.9%) and palmitic acid (C16:0; 13.7–15.2%). Polyunsaturated fatty acids were the predominant fatty acid class, although their relative proportion decreased at 50 °C, where saturated and monounsaturated fatty acids reached their highest values. The PUFA/SFA ratio ranged from 3.08 to 3.76, while the index of atherogenicity and index of thrombogenicity showed only limited variation among treatments. Total glucans ranged from 22.4 to 26.5 g/100 g dry matter, and β-glucans were the dominant glucan fraction in all samples (17.3–21.4 g/100 g dry matter). The highest β-glucan content and β-glucan/total glucan proportion were observed at 50 °C. These results indicate that drying temperature modified the relative fatty acid distribution of I. badia, particularly at 50 °C, but did not reduce β-glucan content under the applied conditions. The calculated lipid indices should be interpreted as comparative descriptors of the relative fatty acid profile rather than evidence of substantial dietary lipid contribution.