Potentially probiotic ice cream from lactose-free milk enriched with Sicilian lemon and passion fruit co-product: microbiological, technological and sensory evaluation

Health concerns have driven the demand for foods enriched with probiotics in various formulations. Ice cream, a dairy dessert consumed by all age groups, has emerged as an appealing vehicle for probiotic delivery. This study aimed to develop, characterize, and conduct a sensory evaluation of ice cream made with lactose-free milk and no added sucrose, incorporating either Sicilian lemon or passion fruit peel flour, and fermented with Lacticaseibacillus paracasei GV17 in association with a commercial co-culture of Streptococcus thermophilus STI-12. The study also evaluated the viability of lactic acid bacteria in the fermented ice cream during storage and under simulated gastrointestinal tract (GIT) conditions. The milk was fermented using the selected strains. Six ice cream formulations were prepared: CON, a control, and CONF, a fermented control, without fruit peel flour; FCLS with the addition of Sicilian lemon peel flour; and fermented FCLSF; FCM with passion fruit peel flour and fermented FCMF. All ice cream formulations met microbiological safety standards. When stored at -18 °C, the GV17 count remained above 9.3 log CFU/mL and STI-12 above 10.9 log CFU/mL. After 360 min under simulated GIT conditions, GV17 counts in the fermented ice creams exceeded 11.5 log CFU/mL. The highest hardness values were observed in FCM (8.23 N) and FCLSF (8.39 N). The highest purchase intention scores were FCM (3.79) and CONF (3.78). The incorporation of fruit peel flours, combined with potentially probiotic LAB, adds value to agri-food co-products and promotes sustainable food production. Fermented formulations maintained probiotic viability during frozen storage and achieved consumer acceptance.