Abstract #T48

# T48
Incorporation of bigels into yogurt to improve survival of probiotics.
X. Zhuang*1, S. Clark1, N. Acevedo1, 1Iowa State University, Ames, IA.

The probiotic yogurt market is strong due to the potential health benefits that probiotics can provide to the host. However, many factors can cause the loss of probiotics viability, including processing conditions and the high acidity of yogurt. The objective of this study was to use bigel technology, a novel encapsulation system, to preserve viability of probiotics incorporated into yogurt. Bigels, composed of an oleogel emulsion (OGE) blended with a hydrogel (HG), were formulated. The OGE was prepared with 20% wt/wt oleogelators (5:5 soy lecithin: stearic acid), 10% wt/wt milk, and soybean oil as the continuous phase. The HG was composed of 25% wt/wt whey protein concentrate (WPC80) and 75% wt/wt deionized water. Probiotic bigels were prepared by homogenizing OGE and HG, followed by incorporation of Lactobacillus acidophilus and Bifidobacterium lactis suspended in milk. For Sundae-style yogurt, 18% wt/wt probiotic bigels were placed at the bottom of containers and covered with yogurt. For Swiss-style yogurt, 18% wt/wt probiotic bigels were mixed into containers with yogurt at a constant stir rate. Three controls were also included in the experimental design: yogurt without probiotics and bigel, yogurt with only probiotics (no bigel), and probiotic bigels from the Sundae-style yogurt. Probiotics viability at 4°C was monitored via plate counts for 6 weeks. The results showed that both the presence of phospholipids and the bigel structure enhanced L. acidophilus and B. lactis viability in yogurt. Throughout 42 d of storage, the presence of soy lecithin exhibited up to 2 log higher cfu/mL values than the control. Additionally, B. lactis and L. acidophilus survived for 7 d longer when inoculated in the structured system than control. The present study demonstrated that probiotics can be efficiently entrapped in bigel systems which extend their viability when incorporated in yogurt. This approach shows a promising future for its application to improve efficacy of probiotics in commercial yogurt production.

Key Words: bigel, probiotics, phospholipids