CERELA   05438
CENTRO DE REFERENCIA PARA LACTOBACILOS
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Whey fermentation by thermophilic lacttic acid bacteria. Breakdown of ƒÒ-lactoglobulin and ƒÑ-lactalbumin
Autor/es:
FERNANDA MOZZI; MICAELA PESCUMA; ELVIRA MARÍA HÉBERT; GRACIELA FONT DE VALDEZ
Lugar:
Bologna, Italia
Reunión:
Simposio; Food Micro. Food safety and food biotechnology: diversity and global impact; 2006
Institución organizadora:
International Committee on Food Microbiology and Hygiene. International Union of Microbiological Societies. Alma matter Studiorum, University of Bologna. Societá Italiana di Microbiologia agroalimentare e ambientale
Resumen:
Whey proteins such as b-lactoglobulin (BLG) and a-lactalbumin (ALA) are an important source of essential amino acids. However, these proteins are poorly digested and potentially allergenic. Lactic acid bacteria (LAB), widely used in the fermented food industry, could be an interesting alternative to hydrolyze BLG and ALA for improving their digestibility and potentially reducing their allergenicity. The aim of this work was to evaluate the growth and the hydrolysis of whey proteins by thermophilic LAB strains in reconstituted whey to further develop a functional hydrolyzed whey-based product. Pasteurized whey (10% w/v) was inoculated (2% v/v) with active LAB cultures (Lactobacillus delbruekii subsp. bulgaricus CRL454, Streptococcus thermophilus CRL804, and L. acidophilus CRL636) and incubated at 37ºC for 24 h. Cell counts (cfu/ml), lactose consumption and organic acids production (HPLC) were determined. Proteolysis was measured by the o-PA test and Tricine SDS-PAGE. Whey proteins hydrolysis was confirmed by growing LAB strains in a chemically defined medium (CDM) with pure BLG, ALA or whey protein concentrate (WPC). Furthermore, peptidolytic activity was determined with intracellular extracts from all strains. All LAB used were able to grow in whey (Dlog cfu/ml: 3-5 after 24 h); S. thermophilus CRL804 being the most acidifying strain (pH: 4.1 and 68 mM lactic acid at 24 h). Overall, the o-PA values were between 0.4 and 1.5 mmol Leu/ml. BLG and ALA were poorly degraded (8 and 14%, respectively) by the assayed LAB during whey fermentation; an increase in protein hydrolysis (BLG: 18%, ALA: 20%) was observed in cells grown in CDM with WPC. Interestingly, BLG was completely degraded by intracellular extracts from all strains.