Effects of addition of strawberry juice pre- or postfermentation on physiochemical and sensory properties of fermented goat milk

Abstract

Fruit juice addition can influence the physiochemical and sensory properties of fermented milk. Effects of adding strawberry juice (15% vol/vol) pre- or postfermentation on particle size, rheology properties, volatile flavor profile, and microstructure of fermented goat milk were investigated. Samples with juice added prefermentation showed larger reinforcement in particle size, apparent viscosity, and storage and loss moduli than samples with juice added postfermentation. Compared with the control, all samples showed improved fruit aroma and reduced goaty flavor; this effect was more remarkable in samples in which juice was added before fermentation. Fermented goat milk with strawberry juice added prefermentation showed the highest levels of 1-hexanol and 2-hexen-1-ol (26.16 and 22.03%, respectively) and the lowest percentage of octanoic acid (2.47%), which are mainly responsible for fruit and goaty flavor, respectively. Microstructure analysis showed that samples with juice added prefermentation had a compact protein network. Results indicated that addition of strawberry juice before fermentation may be a good technology for developing a stirred strawberry fermented goat milk.

Keywords: fermented goat milk; physical property; strawberry juice; volatile profile.