The current research aimed to evaluate the potential effects of Solanum mammosum, Dioon mejiae, and Amanita caesarea on Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus survival and performance after exposure to different harsh conditions such as bile, acid, gastric juice, and lysozyme to mimic the digestive system from mouth to the intestine. Probiotic protease activity was observed to evaluate the proteolytic system. Probiotics were cultured in a broth mixed with plant material, and after incubation, the results were compared to the control sample. Therefore, plant material’s total phenolic compound, total carotenoid compound, antioxidant activity, sugar profile, and acid profile were obtained to discuss their impact on the survival of probiotics. The results indicate that Amanita caesarea negatively affected probiotic survival in the bile tolerance test and positively affected Lactobacillus bulgaricus in the protease activity test. Otherwise, the other plant material did not change the results significantly (p > 0.05) compared to the control in different tests. Consequently, Solanum mammosum and Dioon mejiae had no significant effects (p > 0.05) in increasing probiotic survival.

Carao (Cassia grandis) contains numerous bioactive substances that contribute to gastrointestinal well-being. The present study assessed the potential impacts of carao on the viability and performance of Streptococcus thermophilus and Lactobacillus bulgaricus under various adverse conditions. These conditions included bile, acid, gastric juice, and lysozyme exposure, simulating the digestive process from the mouth to the intestines. The activity of proteases from cultures was monitored to examine their proteolytic capabilities. To achieve this, the cultures were cultivated in a solution containing plant material, and the results were compared against a control sample after an incubation period. Subsequently, the total phenolic content, total carotenoid content, antioxidant activity, sugar profile, and acid profile of the plant materials were analyzed. These analyses were conducted to explore these compounds’ influence on cultures’ survival. Seeds contained the highest total phenols (766.87 ± 11.56 µg GAE/mL), total carotenoid content (7.43 ± 0.31 mg Q/mL), and antioxidant activity (40.76 ± 1.87%). Pulp contained the highest moisture (12.55 ± 0.44%), ash (6.45 ± 0.15%), lipid (0.66 ± 0.07%), protein (16.56 ± 0.21%), sucrose (9.07 ± 0.78 g/100 g), and fructose (3.76 ± 0.06 g/ 100 g). The crust had the highest content of ash (85.14 ± 0.27%) and succinic acid (2.01 ± 0.06 g/100 g). Results indicated that seeds negatively affected cultures’ survival in the bile tolerance test and had positive effects on Lactobacillus bulgaricus in the protease activity test. Otherwise, the other carao tissues could not change the results significantly (p > 0.05) compared to the control in different tests. The carao crust positively affected cultures’ against protease activity, especially in Lactobacillus bulgaricus, and had a negative effect on the growth of S. thermophilus in the lysozyme and gastric acid resistance test.