Effect of process parameters on quality attributes of Lben: Correlation between physicochemical and sensory properties

Abstract

The aim of this work is to investigate for the first time, the interaction effect between process parameters (starter level: 0–1.30 × 101 g/L, time: 7.30–21.70 h and temperature: 18.60–35.40 °C) as well as the effect of each parameter on physicochemical properties, the final count of Lactic Acid Bacteria (LAB) and sensory attributes of Lben. A Central Composite Rotatable Design using Response Surface Methodology was applied to determine individual and mutual effects between process variables. Starter level and temperature are the most influencing parameters of measured properties (p < 0.05). Principal Components Analysis allows the distinction of different groups of products having similar physicochemical and overall acceptability. Viscosity, color, acidity, appearance, and odor of Lben are positively correlated with overall appreciation. The optimized product was prepared using processing parameters combination determined by desirability function (temperature: 18.5 °C, fermentation duration: 20.6 h, and starter level: 1.1 × 101 g/L). Corresponding responses are pH = 4.2, LAB = 1.5 × 109 CFU/mL, viscosity = 3.6 × 10−1 Pa s and global appreciation = 3.6. Twenty and fifteen fatty acids were identified in raw milk and optimized Lben, respectively. The myristic, palmitic, and stearic saturated fatty acids, oleic mono-unsaturated fatty acid, and linoleic polyunsaturated fatty acid are the most abundant in raw milk, traditional, and optimized Lben.