Enzymatic digestion and antioxidant activity of the native and molten globule states of camel α-lactalbumin: Possible significance for use in infant formula

Native- and molten globule states of alpha-lactalbumin (alpha-La) from camel and bovine milk were used for comparative assessment of digestibility and antioxidant activity. The proteolysis assessments were performed in the presence of gastrointestinal enzymes, using the o-phthaldialdehyde assay, and the antioxidant activity was carried out using a 2,20-azinobis(3-ethylenebenzothiazoline-6-sulfonic acid based method. Camel and bovine alpha-La revealed similar sensitivity to proteolysis by pepsin. The degree of hydrolysis (DH) of camel alpha-La by either trypsin or chymotrypsin was noticeably higher than that of the bovine protein counterpart. This can be explained by the different conformational and structural features of these proteins, as shown by studies of intrinsic- and 8-anilinonaphthalene-1-sulfonic acid fluorescence. The greater antioxidant activity of camel alpha-La could be explained by the higher content of antioxidant amino acid residues and different conformational features between bovine and camel alpha-La. The results may suggest that alpha-La produced from camel milk may be used for infant formulae as an alternative to that produced from bovine milk. (C) 2009 Elsevier Ltd. All rights reserved.