Use of red onion (Allium cepa L.) residue extract in the co-microencapsulation of probiotics added to a vegan product.

This study aimed to develop a functional strawberry pulp containing the combination of Lactobacillus casei and bioactive compounds from red onion peel extract into the microparticles formulations to improve bacteria survival during storage and product consumption. To achieve this goal, the addition of different concentrations of red onion peel extract added to the microparticles was evaluated: 5, 20 and 40 %. Microparticles were morphologically characterized and the encapsulation efficiency of the bioactive compounds were evaluated. The physicochemical and microbiological characteristics of the fruit pulp were within the required standards, regardless of the formulation evaluated. As for the pulp added from the microparticles, their physicochemical and microbiological features and probiotic survival under simulated gastrointestinal conditions and storage were analyzed; the size of the microparticles ranged from 136.00 to 305.00 µm. The encapsulation efficiency of both, probiotics and compounds was satisfactory over the different treatments. Indeed, the results pointed out values in the range from 77.77 to 92.11 % for probiotic bacteria; from28.88 to 50.18 % for reducing compounds; 35.72 to 69.01 % for flavonoids; and 25.39 to 60.00 % for total monomeric anthocyanins. The formulations of alginate microparticles and alginate +5 % extract had the best results of L. casei probiotic viability in strawberry pulp under simulated gastrointestinal conditions and during storage at -18 °C for 60 days. In conclusion, red onion peel extract at low concentrations can help the survival of the probiotic L. casei under different conditions.

Viability of microencapsulated Lactobacillus acidophilus by complex coacervation associated with enzymatic crosslinking under application in different fruit juices.

The objective of this study was to produce microcapsules containing Lactobacillus acidophilus LA-02 by complex coacervation followed by crosslinking with transglutaminase and to evaluate the effect of their addition on different fruit juices, as well as the probiotic viability of L. acidophilus and its effect on fruit juices during storage. To this end, L. acidophilus was microencapsulated by complex coacervation, followed by crosslinking with transglutaminase at different concentrations. Probiotics, in their free and microencapsulated forms, were added to orange juice and apple juice at concentrations of 10% and 30%. The obtained microcapsules were characterized in terms of morphology. The viability of probiotics and the effects of their addition on fruit juices were assessed and the juices characterized (with respect to pH and total soluble solids) during 63 days of storage at 4 °C. Orange juice proved to be more suitable for the addition of probiotics, and the survival of probiotics was directly related to pH. The microcapsules had a protective effect on L. acidophilus, prolonging their survival, and the crosslinking process proved to be adequate and promising, ensuring probiotic viability. Thus, the complex coacervation process associated with induced enzymatic crosslinking provided protection for L. acidophilus in different fruit juices, showing an adequate methodology for adding probiotics to this adverse food matrix, guaranteeing the survival of L. acidophilus for up to 63 days, and generating products with innovative and promising probiotic appeal.