Effects of Industrial Thermal Treatments on the Release of Bovine Colostrum Glycoprotein N-Glycans by Endo-β-N-acetylglucosaminidase

Abstract

N-Glycans are structurally similar to human milk oligosaccharides, the gold standard prebiotics for infants. Bovine milk N-glycans released by endo-β-N-acetylglucosaminidase (EndoBI-1) were shown to have similar prebiotic selectivity as human milk oligosaccharides, explaining the interest for N-glycan recovery for use as prebiotics. Industrial thermal treatments such as hightemperature short-time (HTST) and ultra-high-temperature (UHT) might favor the enzymatic deglycosylation of N-glycans through promoting protein denaturation. We investigated the effects of HTST (72 °C for 15 s) and UHT (135 °C for 3 s) on N-glycan release from bovine colostrum glycoproteins by nonimmobilized and amino-immobilized EndoBI-1. A total of 104 N-glycans including isomers/anomers were identified by high-resolution mass spectrometry. In both EndoBI-1 forms, HTST increased the release of N-glycans; however, the impact of UHT on releasing N-glycans was comparable to the nonthermal treatment. Although the amino-immobilized enzyme similarly released neutral N-glycans as the free form, it released fewer sialylated and fucosylated Nglycans.

Bovine Colostrum and Its Potential for Human Health and Nutrition

“…Further, the conjugation of these N -glycans to milk proteins enable different strategies for their recovery. Protein separation from lactose and subsequent treatment to separate N -glycans from their protein conjugates may offer a potentially attractive avenue to purification of these glycans ( 121 ). Thus, N -glycans derived from bovine colostrum, which is exceptionally rich in N -glycosylated proteins ( 122 ), may be a potent source of bioactive glycans to serve as prebiotic substrates.…”

Bovine colostrum as a promising nutraceutical: a systematic review

“…Protein separation from lactose and treatment to separate N -glycans from their conjugates may be a promising method for purifying these glycans. 124 N -glycans from bovine colostrum, high in N -glycosylated proteins, 125 may be a promising source of bioactive prebiotic substrates. Research reveals that complex N -glycans from bovine milk proteins in colostrum are highly selective for specific bacteria in the adult GI microbiome.…”

Bioactive compounds, nutritional profile and health benefits of colostrum: a review

“…Further, the conjugation of these N-glycans to milk proteins enables different strategies for their recovery. Separation of protein from milk and followed by the treatment for the separation of N-glycans offer a potential avenue for their purifications (Bunyatratchata et al 2020 ). Therefore, the derived N-glycans consisting the N-glycosylated proteins can be a formidable source of the substrates that are prebiotic in nature (Cao et al 2019 ).…”