The Effect of Varied Thermal Methods on Sorghum Malt for Mycelial Growth in Pito Production

Abstract

Malted sorghum is widely used in West African cuisine, particularly for pito brewing, but its potential as a substrate for fungal mycelial growth is underexplored. This study evaluated the effects of thermal treatments, pasteurisation and autoclaving on the nutritional composition, microbial safety and mycelial growth of malted sorghum inoculated with Ganoderma resinaceum and Ganoderma enigmaticum . Autoclaving at 121°C for 60 min (A60) effectively preserved grain integrity, reduced grain damage (from 16.4% to 16.0%) and improved particle uniformity. The proximate composition showed that A60 produced the lowest moisture content (3.65 g/100 g) and the highest ash (2.02 g/100 g), protein (11.33 g/100 g) and fat (3.42 g/100 g) contents. Fibre decreased with increasing thermal intensity. Pasteurised grains retained more fibre but were less microbiologically stable. Autoclaving achieved complete microbial decontamination, while pasteurised samples retained mesophilic counts up to 2.93 × 10 2 CFU/g. Mycelial performance varied significantly across treatments. A60 supported the fastest colonisation, with G. enigmaticum reaching a complete colonisation in 10 days (biomass: 55.99%) and G. resinaceum in 12 days (49.29%). In contrast, pasteurised samples exhibited slower colonisation (up to 22 days) and lower biomass (< 20%), with some failing due to microbial interference. Autoclaving at 121°C for 60 min optimised fungal colonisation while maintaining nutrient quality and microbial safety. These findings offer a novel strategy for enhancing the functional potential of sorghum in biotechnological applications such as pito enhancement and mushroom‐enriched foods.