Physicochemical and FTIR-ATR Spectroscopic Characterization of Lipid Deterioration in Raw Horse Mesenteric Fat Under Stress Storage Conditions.

Horse mesenteric fat is a culturally significant and nutritionally valuable food product in Central Asia, yet the kinetics of its oxidative and hydrolytic deterioration under sub-optimal storage conditions remain poorly characterized. Raw mesenteric adipose tissue from ten free-grazing horses in Northern Kazakhstan was subjected to accelerated stress storage at 30 °C and 70% relative humidity for six days, with physicochemical and spectroscopic evaluation on days 0, 3, and 6. Parameters assessed included acid value, peroxide value, refractive index, density, melting point, sensory attributes, and Fourier-transform infrared attenuated total reflectance spectroscopy. The acid value increased markedly from 1.17 ± 0.46 to 32.60 ± 26.18 mg KOH/g by day 6, substantially exceeding the internationally accepted threshold of 2.0 mg KOH/g, while peroxide value rose progressively and density declined. Melting point decreased significantly between days 0 and 3, a physicochemical change that may be associated with hydrolytic and oxidative modification of the lipid matrix, as corroborated by infrared spectral analysis. These results demonstrate that raw horse mesenteric fat is highly susceptible to rancidity, reaching unacceptable quality thresholds within six days, underscoring the urgent need for cold-chain management and evidence-based handling guidelines for this product across the region.