Effects of kiwifruit addition on the physicochemical properties and volatile flavor compounds of fermented goat milk by different strains

Fermented goat milk with kiwifruit (FGMK) and without kiwifruit (FGML) were prepared using 8 isolated lactic acid bacteria strains. Both FGML and FGMK samples showed viable cell counts of 5.70 to 7.14 log cfu/mL and 5.74 to 7.23 log cfu/mL, respectively. After fermentation, milk became brighter and greener. The pH and water-holding capacity results indicated that combining isolated strains and commercial starter cultures gave fermented goat milk good acidification and coagulation properties. Additionally, the incorporation of kiwifruit lowered pH value, increased the titratable acidity, and promoted ketones and esters generation during fermentation. Overall, Latilactobacillus curvatus 142 exhibited superior fermentation performance and excellent flavor score among 8 lactic acid bacteria strains. The electronic nose effectively differentiated goat milk, FGML, and FGMK samples. In addition, the contents of hexanoic, octanoic, and decanoic acid associated with the goaty flavor in K126, K142, K143, and K145 were notably lower than those in L126, L142, L143, and L145. Kiwifruit can improve both the flavor and texture of fermented milk.