Hydrolysis under high hydrostatic pressure as a means to reduce the binding of beta-lactoglobulin to immunoglobulin E from human sera.
Cows' milk allergy is the most frequent food allergy in children, and beta-lactoglobulin (beta-Lg) is a major allergen. Milk-based hypoallergenic ingredients are manufactured by enzymatic hydrolysis, a process that could be improved by the application of high-pressure treatments. This study showed that the treatment of beta-Lg dissolved in buffer with chymotrypsin and trypsin under high pressure for relatively short times accelerated proteolysis by leading to a rapid removal of the intact protein. The rapid proteolysis of the beta-Lg substrate under pressure led to the production, in 20 min, of hydrolysates with lower immunoglobulin (Ig) G binding than those produced in 8 h (chymotrypsin) or 48 h (trypsin) at atmospheric pressure. However, those hydrolysates retained some residual IgE-binding properties that could be traced to the preferential release, during the initial stages of proteolysis, of peptides containing IgE epitopes, such as (Val-41-Lys-60), (Leu-149-Ile-162), and (Ser-21-Arg-40). The formation of these fragments was favored when proteolysis was conducted under high pressure due to the preferential hydrolysis of Arg-40 and Arg-148 by trypsin, and Tyr-42 and Leu-149 by chymotrypsin, all located at the dimer interface of beta-Lg or very close to it. Although our results do not support that trypsin and chymotrypsin under high pressure selectively address the allergenic regions of beta-Lg, it is possible to select the conditions that quickly produce hydrolysates with reduced potential allergenicity that could be used in hypoallergenic foods.
Chicón
R
R
Instituto de Fermentaciones Industriales (CSIC), Juan de la Cierva 3, 28006 Madrid, Spain.
Belloque
J
J
Alonso
E
E
Martín-Alvarez
P J
PJ
López-Fandiño
R
R
D000818:Animals; D002851:Chromatography, High Pressure Liquid; D002918:Chymotrypsin / Q000378:metabolism; D000939:Epitopes; D006868:Hydrolysis; D006874:Hydrostatic Pressure; D007073:Immunoglobulin E / Q000276:immunology / Q000378:metabolism*; D007782:Lactoglobulins / Q000276:immunology / Q000378:metabolism*; D008892:Milk / Q000201:enzymology* / Q000378:metabolism; D016269:Milk Hypersensitivity / Q000276:immunology / Q000517:prevention & control; D010446:Peptide Fragments; D013997:Time Factors; D014357:Trypsin / Q000378:metabolism
D000939:Epitopes; D007782:Lactoglobulins; D010446:Peptide Fragments; D007073:Immunoglobulin E; D002918:Chymotrypsin; D014357:Trypsin