Novel Formulation of Low-Fat Milk Chocolate: Impact on Physicochemical and Sensory Properties

This study proposes a dual-approach strategy to formulate reduced-fat milk chocolate by combining cocoa butter (CB) substitution with emulsifier-based rheological optimization. CB was partially replaced at 20%, 30%, and 40% using whey protein isolate (WPI) and inulin (IN) blends (70:30, 50:50, 30:70 w/w). CB reduction increased plastic viscosity and yield stress, particularly in WPI-rich systems. The 50:50 WPI:IN ratio consistently minimized rheological drawbacks while maintaining melting, texture, and sensory quality. Caloric content was reduced by up to 9% (~50 kcal/100 g), most notably in IN-dominant samples. To overcome flow challenges at high substitution levels, emulsifiers—lecithin, ammonium phosphatide (AMP), and polyglycerol polyricinoleate (PGPR)—were assessed. AMP (≤0.5% w/w) and PGPR (0.15–0.3% w/w) effectively reduced viscosity and yield stress; lecithin showed limited effect above 0.6%. The optimized system (0.5% AMP + 0.15% PGPR) applied to 40% CB-reduced chocolate with 50:50 WPI:IN restored desirable rheology (3.42 Pa·s viscosity; 7.91 Pa yield stress) and improved mouthfeel and acceptability. This integrated formulation enables significant fat and calorie reduction without compromising product quality, supporting the development of healthier chocolate products.