α-Lactalbumin(α-LA) is one of the main allergens in cow milk.In this study,α-LA was glycated with different size saccharides(glucose,maltose,maltotriose,maltotetraose and maltopentaose) to study the effect of the size of the saccharide on protein antigenicity.The results showed that,with an increase in the size of the saccharide,the degree of glycation decreased.The antigenicity of all glycated samples significantly decreased with an increase in incubation time,suggesting that the extent of glycation might be an important factor to decrease antigenicity.However,the largest reduction of antigenicity was observed after incubation with maltotriose,whose antigenicity declined by 51.67%.This could be related to the difference in binding specificity of the saccharides to the allergenic sites of the protein.Through comparing the glycation sites and the reduction of the antigenicity by incubating with the five saccharides,we found Lys58 may play an important role in the reduction of the antigenicity of α-LA.The results suggested that the glycation size could affect the glycation site,and eventually impact the antigenicity of the glycated protein.When the main epitope was glycated,the degree of antigenicity reduction increased with the increase in the size of the saccharide.