Protective role of wood hemicelluloses: Enhancing yeast probiotics survival in spray drying and storage
Thao M. Ho, Amin Yousefvand, Heikki Suhonen, Per E. J. Saris, Kirsi S. Mikkonen
Abstract
• Wood hemicelluloses were effective wall materials for yeast microencapsulation. • Wood hemicelluloses ensured >90 % yeast survival rate, similar to gum Arabic. • Yeasts were occupied within spherical microcapsules with a 1 − 2 µm coating layer. • Glucuronoxylans protected yeasts during storage better than galactoglucomannans. Wood hemicelluloses, specifically galactoglucomannans (GGM) and glucuronoxylans (GX) are investigated for their efficacy in spray-dried microencapsulation of Saccharomyces cerevisiae subsp. boulardii (SB). This study demonstrated that GGM and GX effectively protected SB during spray drying at feed concentrations of 15 and 20 % and inlet air temperatures of 105 and 140 °C, ensuring survival rates over 90 %, comparable to gum Arabic, with all achieving over 10 8 cfu/g in the microcapsules. However, GGM and GX were unable to sustain SB viability when the microcapsules were stored at 33 and 75 % RH (22 °C), beyond 21 and 7 days, respectively. When stored at 4 °C, GX demonstrated a greater ability to protect SB than GGM, with log-cycle reductions of 3 and 6, respectively, after two months. Microstructure analyses showed almost all SB were entrapped by wall materials, with many microcapsules having a wall thickness of 1 − 2 µm. Overall, GX is effective for stable yeast probiotic powders, enabling the development of new probiotic enhanced formulations with prolonged viability and stability.