Effect of spray drying on the viability and resistance to simulated gastrointestinal digestion in lactobacilli

PAEZ, R.; LAVARI L; VINDEROLA, G.; AUDERO G; CUATRIN, A; ZARISTKY, N.; REINHEIMER, J.

FOOD RESEARCH INTERNATIONAL

ELSEVIER SCIENCE BV

Lugar: Amsterdam; Año: 2012 vol. 48 p. 748 - 754

0963-9969

Commercial probiotic bacteria are delivered mainly as frozen or freeze-dried cultures. However, spray drying is a lower cost technology that could be used for the production of probiotic cultures. The aim of this work was to screen among lactobacilli strains for candidates able to survive spray drying and to study the effects of a preliminary heat treatment on post-drying survival and resistance to simulated gastrointestinal digestion. Thermal resistance (survival to exposure to 60ºC for 5 min) in MRS broth or in 10% (w/v) skim milk was assessed in 22 strains of Lactobacillus casei, L. paracasei, L. acidophilus and L. plantarum. Five strains (L. casei Nad, L. plantarum com, L. paracasei A13, L. plantarum 8329 and L. acidophilus A9) were selected for spray drying in 20% (w/v) skim milk and storage at 5, 25 or 37ºC for 75 days. For L.p. A13, L.p. com and L.a. A9 no differences in cell viability were observed due to spray drying. However, for L.c. Nad and L.p. 8329 cell death due to spray drying was 0.16 and 0.49 log orders CFU ml-1 when thermal treatment was applied and 0.85 and 0.95 log cycles, respectively, without preliminary thermal treatment, showing that heat treatment enhanced survival to spray drying. The application of a heat treatment was effective for enhancing survival during storage of L.p. 8329, irrespective of the storage temperature and period. No significant cell lost at 5 and 25ºC was observed for L.c. Nad. For this strain, at 37ºC no cell counts of lactobacilli were observed after 30 days of storage. For L.a. A9, L.p. com and L.p. A13 a reduction in cell viability was observed along storage as temperature increased. Resistance to simulated gastrointestinal digestion was enhanced by spray drying. The application of a mild heat-treatment before spray drying may enhance cell survival during storage and the resistance to gastrointestinal digestion. Spray drying might be used for enhancing cell functionality in a strain-dependant way.