Investigation of the effect of plant antioxidants on the color characteristics of cooked sausage using low-value by-products

The study focuses on controlling the color formation and color stability of cooked sausages by deliberately varying two functional ingredients: collagen hydrolysate from low-value by-products and cranberry powder. The aim was to quantitatively describe the dose-response effects of these factors on the integral color stability and to propose a technologically feasible optimal range. The methodology included the preparation of five experimental samples (control; 10% hydrolysate; and 10% hydrolysate with 1, 2, and 3% cranberry), instrumental color evaluation in the CIE Lab* system before and after 60 minutes of exposure and calculation of the percentage of stability based on normalized changes in L*, a*, b*. Based on these experimental points, a full-square regression model RSM was evaluated, after which theoretical values were calculated on a regular grid of factors (hydrolysate 0–15%, cranberry powder 0–3%) for surface visualization and optimization. The experimental data showed that the best color stability indicator was demonstrated by the sample with 10% hydrolysate and 3% cranberry powder – 90,24%. Approximation by the RSM (R²=0,995; R²_adj=0,991) revealed a dominant positive linear contribution of cranberry powder, a stable negative linear contribution of hydrolysate, and negative quadraticity for cranberries (saturation of the effect); the interaction of factors is statistically insignificant. Practical significance – recommendation to minimize the proportion of hydrolysate to about 5-10% and dose cranberries at 2-3% to achieve a stability plateau with low sensitivity to dosing errors.