Produção de fermento lático endógeno para produção de queijo de coalho com características do sertão alagoano

Abstract

Immobilization of lactic acid bacteria (LAB) isolated from cheese curd is an alternative to preserve and use these cultures as lactic ferments, especially for large consumer acceptance of the curd cheese produced from raw milk, then the use of endogenous BAL dry is a method for obtaining a product sensorially acceptable and sanitary-hygienic standards. The conservation of these micro-organisms by lyophilization techniques and spray-drying has been studied and improved , and the freeze-drying technique most widespread commercially, but the second has been seen as an alternative. With this, the objective of this study was to evaluate the influence of the techniques of drying, spray-drying and freeze-drying on viability of BAL, L. paracasei and L. plantarum isolated from artisan cheeses. For the preparation of the cultures, the strains were activated in MRS broth (Man, Rogosa & Sharpe) and cultured for an increase in cell mass. To obtain a cell pellet, the broth was centrifuged and the biomass resuspended in reconstituted skim milk ( LDR) 20 % to lyophilization , and LDR 20% + 0.5% yeast extract, following fermentation for spray-drying. The solution subjected to the drying process by spray-drying, had its pH adjusted prior to being subjected to the process. The survival of the BAL was determined by counting the number of viable cells in colony forming units per mL and per gram before and after drying, respectively, as well as determining the storage period. The particles were characterized by Scanning Electron Microscopy (SEM) and evaluated their rehydration. Both techniques were effective for viability after drying and maintenance. Both techniques were effective in viability after drying and maintenance powder during storage. The lyophilization best values of the rate of viability of the strains were obtained, however, the drying technique has rapidly spray-drying process execution significant in relation to lyophilization. The particles of spray-drying are shown with rounded shape with no cracks and concavities, in the lyophilization particles are of irregular formats, in the form of higher dimension plates. In both techniques, showed-up with ease of rehydration. When evaluating drying techniques, it should be borne in mind that the viability rateis also dependent from each culture, and the culture medium, cell, types, physiological state and the processused. Each specific cultureis analyzed, and the study of immobilization should be treated individually for the best survival rate.