| Soy foods are more and more accepted as healthy foods. Specifically, soy energy bars share a main branch of the soy foods market in the U.S. However, intestinal bloating and flatulence induced by consumption of soy foods often compromise their favorable properties. This is due to the presence of indigestible oligosaccharides (alpha-galactosides), mainly raffinose and stachyose. This research was aimed to develop innovative soy energy bars containing functional probiotics, which could be used to fortify soy foods and to reduce a-galactosides upon consumption.;Firstly, a dry powder ingredient containing functional probiotics was developed. The probiotics, Lactobacillus acidophilus LA-2 and Lactobacillus fermentum ATCC 14931, were able to produce alpha-galactosidase, the specific enzyme that hydrolyzes raffinose and stachyose, in quite high levels, at 4.1 x 10-3 and 2.5 x 10-3 U/mg, respectively. Further, the enzyme activity was significantly induced (P = 0.05) to 5.0 x 10-3 and 4.1 x 10-3 U/mg for L. acidophilus LA-2 and L. fermentum ATCC 14931, respectively, by growing the cells in the presence of raffinose. Microencapsulation was applied to protect the probiotics, and it was demonstrated that the combination of kappa-carrageenan and inulin with the proportion of 1.9:0.1 (w:w) as wall materials, significantly retained the viability of the probiotics through freeze-drying (P ≤ 0.05). The microencapsulated cells were subsequently frozen at -20°C overnight and freeze-dried. Scanning electron microscopic images confirmed that the morphology of the microcapsules was well preserved after freeze-drying.;Further, innovative soy energy bars containing microencapsulated L. acidophilus LA-2 were manufactured and their shelf life was analyzed during a ten-week storage under vacuum packaging in the dark at both 4°C and room temperature. Compared with room temperature storage, the 4°C storage condition preserved the soy energy bars with their original properties better. Over time, no significant changes were found in pH, moisture content, yellowness and viability of the probioitcs for the innovative soy energy bar stored at 4°C (P ≤ 0.05). Although a significant increase in water activity, texture and redness, and a significant decrease in lightness were found for the bars stored at both 4°C and room temperature over time, the changes caused by 4°C storage was much slower than that caused by room temperature storage (P ≤ 0.05). |
