Potentially probiotic vegetable ricotta cheese-like product produced from pumpkin seeds: evaluation of physicochemical characteristics and probiotic viability

Cheeses are popular dairy products, with increasing demand for ricotta and probiotic cheeses due to their versatility and nutritional benefits. However, there is a growing population with dietary restrictions, including vegans, allergic, and lactose intolerants, prompting the food industry to create new plant-based alternatives resembling traditional products. Thus, this study aimed to produce a pumpkin seed-based ricotta cheese-like product added with probiotics and evaluate the physicochemical characteristics and probiotic viability in this product during the shelf life. The pumpkin seeds were peeled, sanitized and crushed in water, and the extracted liquid was boiled for protein thermal coagulation with the formation of the protein network. After obtaining the curd, sodium chloride (1%) and Lactiplantibacillus plantarum and Lacticaseibacillus rhamnosus were added. A control sample (without added probiotic) was also produced. After production, the samples were stored at 5°C and pH, acidity, syneresis and lactic acid bacteria counts were performed at 0 and 7 days. The pH did not change during the shelf life (range between 6.92-6.64) of the samples (p>0.05). However, the probiotic samples showed an increase in acidity after 7 days at 5°C (0.40-0.43 to 0.62-0.67 expressed in % lactic acid) (p<0.05), with no difference between the probiotics (p>0.05), which may indicate the acidic compounds production by microorganisms. Regarding the probiotic viability, both probiotics exhibited high counts, with L. plantarum (9.48±0.21 log CFU/mL) showing higher viability after 7 days compared to L. rhamnosus (7.98±0.81 log CFU/mL) (p<0.05). Furthermore, after 7 days, the cheese added with L. plantarum showed less syneresis (56% reduction) compared to the control sample (p<0.05). Based on the results, the potential of the pumpkin seed-based ricotta cheese-like product as a carrier of probiotics with similar characteristics to the traditional product is highlighted. Future work is needed to assess the overall quality of the product, including sensory evaluation.