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Impacts of zinc sulphate and cupric chloride on characteristics and antioxidant capacities of glycated products (GPs) derived from casein hydrolysate (CH) and xylose were studied. The browning degree of xylose–CH GPs was the largest at zinc sulphate addition of 15 mg L−1, while its browning degree increased with cupric chloride extended from 0 to 15 mg L−1. Loss of free amino groups, fluorescence intensity and the 2,2-diphenyl-1-picryl-hydrazyl (DPPH) radical scavenging capacity of xylose–CH GPs increased with the increase of cupric chloride addition, but loss of amino groups, fluorescence intensity and DPPH radical scavenging capacity were largest at the zinc sulphate addition of 15 mg L−1. The addition of zinc sulphate and cupric chloride promoted production of higher and smaller molecular substances in xylose–CH GPs and CH. Therefore, zinc sulphate and cupric chloride promoted glycated reaction of xylose and CH and enhanced antioxidant activity of xylose–CH GPs. [ABSTRACT FROM AUTHOR]

Impacts of ultrafiltration and hydrolysis on antioxidant abilities of Maillard reaction products (MRPs) derived from whey protein isolate (WPI) and galactose (Gal), were evaluated in this study. Fraction (MW > 50 kDa)of WPI-Gal MRPs prepared with ultrafiltration, had the strongest antioxidant activity. The trichloroacetic acid (TCA, 2–8%) treatment could effectively enhanced antioxidant activities of WPI-Gal MRPs. WPI-Gal MRPs had higher degrees of hydrolysis and antioxidant activity than heated WPI. With hydrolysis time of pepsin and trypsin extended up, degrees of hydrolysis and antioxidant activities of WPI-Gal MRPs and WPI gradually increased (P < 0.05). Furthermore, reverse phase HPLC analysis showed that WPI-Gal MRPs was easier to be hydrolyzed and had smaller molecular peptides than heated WPI. • Fractions (MW > 50 kDa) of WPI-Gal MRPs had the strongest antioxidant activity. • TCA treatment effectively enhanced antioxidant activities of WPI-Gal MRPs. • WPI-Gal MRPs had higher hydrolysis degrees and antioxidant activity than heated WPI. [ABSTRACT FROM AUTHOR]