Effects of Kluyveromyces marxianus SP-1 Cofermentation on Fatty Acid Composition and Volatile Compound Profiles in Goat Milk from Two Dairy Goat Breeds

Abstract

The characteristic goaty flavor of goat milk (GM) limits consumer acceptance and is associated with its fatty acid (FA) composition and volatile compound (VC) profile, both of which vary with dairy goat breed and fermentation strategy. This study evaluated the effects of cofermentation with Kluyveromyces marxianus SP-1 and a commercial lactic acid bacteria (LAB) starter on the FA composition and VC profiles of GM from Xinong Saanen and Guanzhong goats. Nonfermented and fermented milk samples were analyzed using GC-MS for FA composition and SPME-GC-MS for VC profiling. FA composition was expressed as the relative proportions of total identified FAs, whereas VCs were evaluated based on relative abundances. Significant breed-dependent differences in FA composition were observed (p ≤ 0.05), whereas fermentation induced only minor changes in FA profiles within the same breed. In contrast, cofermentation was associated with marked changes in VC profiles, including lower relative abundances of aldehydes and goaty-associated acids and higher relative abundances of alcohols and aroma-related esters associated with cheesy, buttery, fruity, and floral aroma characteristics. Multivariate analyses (HCA and PCA) further demonstrated clear separation of samples according to fermentation strategy, indicating distinct differences in volatile profiles among treatments. Because total FAs rather than free FAs were analyzed, and no yeast-only fermentation control was included, the results reflect overall FA composition and comparative changes in volatile profiles without distinguishing the specific contributions of K. marxianus SP-1 and the LAB starter. Overall, cofermentation with K. marxianus SP-1 and the LAB starter was associated with modified volatile profiles of fermented GM, whereas dairy goat breed exerted a stronger influence on FA composition than fermentation.