Uncovering the Functional Potential of Goat Milk: Physicochemical and Rheological Comparison Across Local Goats in Gorontalo Indonesia

The physicochemical and rheological characteristics of goat milk are pivotal in determining its processing potential and nutritional value. Despite Indonesia’s rich diversity in goat breeds, scientific data comparing the milk quality across these breeds remain scarce. This study investigated the physicochemical, rheological, structural, and protein characteristics of raw goat milk from four genotypes—Kacang, Local Goat, Etawa Crossbreed, and Saanen Crossbreed—reared under traditional farming conditions in Gorontalo, Indonesia. The aim was to identify breed-specific differences that may influence milk’s nutritional quality and processing suitability. A total of 48 raw milk samples were analyzed using standard compositional assays, sodium dodecyl sulfate–polyacrylamide gel electrophoresis, densitometry, amino acid profiling, laser confocal microscopy, rotational rheometry, and colloidal stability measurements. These methods provided detailed insights into protein structure, micelle behavior, and textural properties. The results revealed that crossbred goats, particularly Saanen and Etawa, produced milk with higher protein content, stronger casein expression, greater viscosity, and richer profiles of glutamic acid, proline, and threonine. Conversely, Kacang goats showed higher whey protein content and elevated sulfur amino acids, such as cysteine and methionine. All samples exhibited pseudoplastic flow behavior and comparable zeta potential and particle size, indicating similar colloidal stability. These findings demonstrate the influence of genotype on goat milk functionality and support its valorization in developing sustainable and differentiated dairy products with enhanced nutritional and technological properties. .