Investigation of Damage Mechanism in Baijiu Yeast during Spray Drying at the Molecular Scale

The unclear micronano damage mechanism of high-quality liquor yeast during spray drying impedes its large-scale application and hinders the high-quality development of the liquor industry. To address this problem, we designed a real-time sampling system for spray drying experiments using modified Sporidiobolus johnsoniiA (MSJA) as the model organism. Through field emission scanning electron microscopy (FESEM), laser scanning confocal microscopy (LSCM), and cryogenic transmission electron microscopy (Cryo-TEM), we directly observed micronano damage to MSJA cell walls and membranes. Molecular biology analysis revealed that transverse shear forces induce “approximate gel phase transition” and “dislocation slip pore formation” in phospholipid bilayers at moisture content ≤ 21% or temperature >53 °C, while “near bimodal transition” and “collapse” occur at moisture content ≤ 7% or temperature >71 °C. These mechanisms explain the accelerated inactivation and rapid mass inactivation of MSJA during spray drying, respectively.