Effects of freeze drying protectant on quality of lactic acid bacteria fermented food prepared from milk or egg white powder

摘要

Lactic acid bacteria(LAB) fermented food was prepared with milk or egg white powder(EWP) and added with freeze drying protectant(FDP). 0.2 percent of Tween 80 or 1 percent of ascorbate was added to milk sample and 3 percent of raffinose or 1 percent of ascorbate was added to EWP sample. Effects of FDP on sensory property, volatile aroma compounds and physical property of LAB fermented food were investigated. In case of non-freeze dried samples, sensory properties of milk sample with ascorbate were slightly better than those of reference sample(milk), while sensory properties of EWP sample or EWP sample with FDP were slightly inferior to reference sample. Sensory properties of all of the freeze dried/reconstituted samples were not different. Sensory properties of milk sample with ascorbate were reduced by freeze drying/reconstitution, while those of sample with ascorbate were not changed. Although all of the volatile aroma compounds were reduced by freeze drying, the residual ratio was slightly different between milk samples and EWP samples. Difference in volatile aroma compounds between milk samples and EWP samples before freeze drying was relatively large, while difference between two sample groups after freeze drying/reconstitution was relatively small. Rheological properties of milk samples were markedly changed by freeze drying/reconstitution, while those of EWP samples were changed slightly.