@article {ferreira_short_2010,
	title = {Short communication: effect of kefir grains on proteolysis of major milk proteins},
	journal = {Journal of Dairy Science},
	volume = {93},
	number = {1},
	year = {2010},
	note = {<p>{PMID:} 20059900</p>
},
	pages = {27{\textendash}31},
	abstract = {<p>The effect of kefir grains on the proteolysis of major milk proteins in milk kefir and in a culture of kefir grains in pasteurized cheese whey was followed by reverse {phase-HPLC} analysis. The reduction of kappa-, alpha-, and beta-caseins {(CN)}, alpha-lactalbumin {(alpha-LA)}, and beta-lactoglobulin {(beta-LG)} contents during 48 and 90 h of incubation of pasteurized milk {(100mL)} and respective cheese whey with kefir grains (6 and 12 g) at 20 degrees C was monitored. Significant proteolysis of {alpha-LA} and kappa-, alpha-, and beta-caseins was observed. The effect of kefir amount (6 and 12 {g/100mL)} was significant for {alpha-LA} and alpha- and {beta-CN.} {alpha-Lactalbumin} and {beta-CN} were more easily hydrolyzed than {alpha-CN.} No significant reduction was observed with respect to {beta-LG} concentration for 6 and 12 g of kefir in {100mL} of milk over 48 h, indicating that no significant proteolysis was carried out. Similar results were observed when the experiment was conducted over 90 h. Regarding the cheese whey kefir samples, similar behavior was observed for the proteolysis of {alpha-LA} and {beta-LG:} {alpha-LA} was hydrolyzed between 60 and 90\% after 12h (for 6 and 12 g of kefir) and no significant {beta-LG} proteolysis occurred. The proteolytic activity of lactic acid bacteria and yeasts in kefir community was evaluated. Kefir milk prepared under normal conditions contained peptides from proteolysis of {alpha-LA} and kappa-, alpha-, and beta-caseins. Hydrolysis is dependent on the kefir:milk ratio and incubation time. {beta-Lactoglobulin} is not hydrolyzed even when higher hydrolysis time is used. Kefir grains are not appropriate as adjunct cultures to increase {beta-LG} digestibility in whey-based or whey-containing foods.</p>
},
	keywords = {Animals, Bacteria, Cereals, Cheese, Cultured Milk Products, Food Technology, Milk, Milk Proteins, Yeasts},
	issn = {1525-3198},
	doi = {10.3168/jds.2009-2501},
	url = {http://www.ncbi.nlm.nih.gov/pubmed/20059900},
	author = {Ferreira, I M P L V O and Pinho, O and Monteiro, D and Faria, S and Cruz, S and Perreira, A and Roque, A. C. A. and Tavares, P}
}
