Thermal resistance and stability of multilayers embedding probiotic structure

Evidence from gut microbiota studies highlights the importance of probiotics in promoting human health alongside the market's demand. However, probiotics are particularly sensitive to unfavorable factors in a storage environment (e.g., humidity, temperature, oxygen, and light), frequently resulting in reduced viability during shelf life and a loss of original benefits. This study focused on the structure of multilayer embedding, with particular attention on enhancing the Lactobacillus plantarum thermal resistance, moisture permeability, and stability of probiotics for storage while considering high packaging efficiency and cost-effectiveness. The log values of viable bacteria in casein/pectin condensates cross-linked with transglutaminase (TGase) for 1 and 5 h, while heated at 80 °C for 5 min, were 5.33 and 5.25 CFU/g, respectively, with higher thermal tolerance than the control group (casein, 4.56 CFU/g). In addition, the storage stability results for 15 days at 37 °C with 51 % relative humidity (RH) showed the same trend. The groups cross-linked for 1 and 5 h had higher viability than the control group, implying that the powders performed satisfactorily regarding hygroscopicity. Similarly, after 5 min of heating at 80 °C, the viable bacteria were higher in groups with different ratios of canola oil to palm stearin (100:0, 70:30, and 50:50) than in the control group. Moreover, TGase cross-linked casein/pectin may enhance stability and improve probiotic powders' thermal tolerance, along with different emulsification oil embedding ratios. Hence, the findings of this study may be applied to encapsulating and preserving environmentally sensitive bioactive components, including probiotics.