Microstructure
The micrographs of yogurt gels made with 0.5, 3, or 4% culture inoculation rates and different incubation temperature (40 or 45.7°C) are presented in Figures 5 and 6. In yogurts formed at 40°C, gels made with 0.5% culture exhibited a clustered protein network at gelation time,whereas a more interconnected network was observed at the time of LTmax (Figure 5a and d). At the end of fermentation (pH 4.6), protein clusters became denser and were closer to each other, and yogurt gels exhibited a more branched and interconnected protein matrix compared with yogurt gel at the earlier time points (Figure 5). A similar trend was observed in yogurt gels inoculated with 3% and incubated at 40°C (Figure 5e and h). At LTmax time and the end of fermentation(pH 4.6) ,yogurt gel inoculated with 0.5% and incubated at 40°C was less interconnected and exhibited larger pores (and clusters) compared with yogurt gels inoculated with 3 or 4%(Figure 5g, h, and i).