Diversity in growth and protein degradation by dairy relevant lactic acid bacteria species in reconstituted whey

Abstract

<jats:p>The high nutritional value of whey makes it an interesting substrate for the development of fermented foods. The aim of this work was to evaluate the growth and proteolytic activity of sixty-four strains of lactic acid bacteria in whey to further formulate a starter culture for the development of fermented whey-based beverages. Fermentations were performed at 37°C for 24 h in 10 and 16% (w/v) reconstituted whey powder. Cultivable populations, pH, and proteolytic activity (<jats:italic>o</jats:italic>-phthaldialdehyde test) were determined at 6 and 24 h incubation. Hydrolysis of whey proteins was analysed by Tricine SDS-PAGE. A principal component analysis (PCA) was applied to evaluate the behaviour of strains. Forty-six percent of the strains grew between 1 and 2 Δlog CFU/ml while 19% grew less than 0·9 Δlog CFU/ml in both reconstituted whey solutions. Regarding the proteolytic activity, most of the lactobacilli released amino acids and small peptides during the first 6 h incubation while streptococci consumed the amino acids initially present in whey to sustain growth. Whey proteins were degraded by the studied strains although to different extents. Special attention was paid to the main allergenic whey protein, β-lactoglobulin, which was degraded the most by<jats:italic>Lactobacillus acidophilus</jats:italic>CRL 636 and<jats:italic>Lb. delbrueckii</jats:italic>subsp.<jats:italic>bulgaricus</jats:italic>CRL 656. The strain variability observed and the PCA applied in this study allowed selecting appropriate strains able to improve the nutritional characteristics (through amino group release and protein degradation) and storage (decrease in pH) of whey.</jats:p>

The changes of proteins fractions shares in milk and fermented milk drinks

“…The largest increase in the proportion of polypeptides (over 400%) was observed in the Bifi dobacterium milk, and of γ-casein (360%) in kefi r. The content of high (Table 3). According to Liu et al (2012), Pescuma et al (2012), Bertrand-Harb et al (2003 Streptococcus thermophillus and Lactobacillus delbrueckii ssp.…”

“…During the production of fermented milk drinks, hydrolysis is performed by enzymes of lactic acidfermenting bacteria. The microbiological composition of starter cultures can determine the range, as well as the development of, protein hydrolysis, and the composition of peptides and other products that form after hydrolysis, because the proteolytic activity of the starter microfl ora is diff erent (Alhaj et al, 2007;Bertrand-Harb et al, 2003;Liu et al, 2012;Pescuma et al, 2008;Pescuma et al, 2012;Reguła and Bonczar, 2005;Sfaxi et al, 2012;Tzvetkova et al, 2007;Yadav et al, 2007).…”

Instrumental texture and sensory evaluation of fermented dairy beverages processed with reconstituted goat whey powder and a co-culture of Streptococcus thermophilus and Lactobacillus casei

“…Nonetheless the use of in natura whey is limited due to its perishable components (Morais et al, 2015). To overcome this limitation, the processing of whey by drying can turn it in a valuable ingredient for the production of a functional beverage through fermentation by lactic acid bacteria (Pescuma et al, 2012).…”

Proteolytic activity of Enterococcus faecalis VB63F for reduction of allergenicity of bovine milk proteins

“…Cow milk allergy is an immunological reaction related to the recognition and binding of IgE to specific epitopes in milk proteins (Cocco et al, 2003;Claeys et al, 2013). β-Lactoglobulin is the main milk protein recognized by IgE, accounting for 80% of allergy cases and identified as the main agent of CMA development (Pescuma et al, 2012;Claeys et al, 2013). However, milk caseins (α S1 -, α S2 -, β-CN) also play a relevant role in the development of CMA (Docena et al, 1996;Natale et al, 2004;Restani et al, 2009;Bu et al, 2010;El-Ghaish et al, 2010), and the linear epitopes present in this protein fraction of milk are related to the persistence of allergy and the occurrence of more severe symptoms (Vila et al, 2001).…”