Effect of ultrasound on cell viability and storage of dehydrated jackfruit (Artocarpus heterophyllus Lam.) impregnated with Lactobacillus casei

This work evaluated use of ultrasound on probiotic concentration and storage stability of dehydrated jackfruit impregnated with Lactobacillus casei. Impregnation was performed at atmospheric pressure (AI) or vacuum (VI), and with ultrasound (US + AI; US + VI) pretreatment. The impregnated jackfruit was dried at 50 °C and stored in vacuum packaging for 28 days at 4 °C. Ultrasound pretreatment and impregnation resulted in higher moisture content, showing greater capacity for infiltration of the impregnation liquid. Regarding to drying, the control sample (without ultrasound and impregnation) reached the dynamic equilibrium in 220 min, while AI impregnated sample showed a shorter time (64 min). Higher probiotic concentration was found after the US + AI treatment when compared with the US + IV (p < 0.05). Regarding the storage study, the US + AI treatment allowed the product to have a concentration of 7.99 ± 0.07 log10 CFU/g, and after 28 days, it reduced to 0.75 log10 CFU/g. The impregnation resulted in a microbial content, after drying, in its less effective process, of 6.79 ± 0.20 log10 CFU/g, a minimum concentration enough to be considered a probiotic product. The impregnation method influenced both drying and probiotic concentration during the process and storage of the product.