Fractionation and characterisation of sialylated-mucin glycoprotein from edible birds' nest hydrolysates through anion exchange chromatography.

Edible bird's nest (EBN) is made up of sialylated-mucin glycoprotein with various health benefits due to its high antioxidative activity. However, as a macromolecule with distinct charged sialic acid and amino acids, fractions with different charges would have varied physicochemical properties and antioxidant activity, which have not been studied. Therefore, this study aimed to fractionate and purify the enzymatic hydrolysed of cleaned EBN (EBNhc) and EBN by-product (EBNhbyp) through anion exchange chromatography (AEC), and determine their molecular weights, physicochemical properties, and antioxidative activities. Overall, 26 fractionates were collected from enzymatic hydrolysate by AEC, which were classified into 5 fractions. It was found that the positively charged fraction of EBNhc (CF 1) and EBNhbyp (DF 1) showed the significantly highest (p < 0.05) soluble protein contents (22.86 and 18.40 mg/g), total peptide contents (511.13 and 800.47 mg/g) and ferric reducing antioxidant power (17.44 and 6.96 mg/g) among the fractionates. In conclusion, a positively charged fraction (CF 1 and DF 1) showed more desired physicochemical properties and antioxidative activities. This research suggests the potential of AEC fractionation as a technology to purify EBN and produce positively charged EBN fractionates with antioxidative potential that could be applied as food components to provide health benefits.

Effects of post-drying methods on pomelo fruit peels.

Changes in physicochemical properties of moisture, ash, and fat contents, and color, due to freeze and oven post-drying treatments on flavedo, albedo, and lamella pomelo fruit peels were investigated. Physicochemical properties influence consumer acceptability and only a few studies are known. Pomelo peels were subjected to freeze drying and conventional drying at 60°C. Fresh pomelo peel was used as a control. Post-drying treatment changes in moisture, ash, and fat contents were observed, compared to controls. Minimal color changes were observed for freeze drying, compared with oven drying for flavedo, albedo, and lamella. Useful information for evaluation of drying treatments that can be used on pomelo peels is provided.