Antifungal Capacity of Microcapsules Containing Lactiplantibacillus plantarum TEP15 or Lactiplantibacillus pentosus TEJ4

Abstract

The use of lactic acid bacteria (LAB) for the biocontrol of fungi that cause fruit and vegetable deterioration is a highly promising strategy. However, one of the main challenges lies in maintaining both viability and antifungal activity even in conditions that are unfavorable for LAB. The microencapsulation of LAB can minimize the impact of environmental conditions, helping to maintain viability, but there is still little information on what occurs with respect to antifungal activity. Therefore, the objective of this study was to evaluate the effect of microencapsulation with several polymer blends on the viability and antifungal activity of Lactiplantibacillus plantarum TEP15 and L. pentosus TEJ4. Sodium alginate (2%), sodium alginate–gum arabic (2%:1%), sodium alginate–k-carrageenan (2%:0.05%), and sodium alginate–whey protein (0.75%:1.5%) were used as encapsulating polymers. After processing (day 0), as well as after 14 and 28 days of storage, the encapsulation efficiency, moisture content, bead size, and survival were evaluated. Likewise, the encapsulated bacteria were subjected to in vitro tests against Colletotrichum gloeosporioides, Penicillium AT21H10, and Fusarium sp. Capsules with sizes ranging from 1.47 mm to 1.88 mm were obtained, and all the wall materials tested had more than 85% encapsulation efficiency and allowed survival rates greater than 90% and 80% to be maintained after 14 and 28 days of storage, respectively. The encapsulated LAB inhibited the growth of mycelia by up to 100%, but, against spores, the greatest inhibition was 22.08% for all the fungi tested.