Evaluation of physicochemical properties, amino acid profile and bioactivities of edible Bird's nest hydrolysate as affected by drying methods

• Published in: Food science & technology 2020-09, Vol.131, p.109777, Article 109777
• Main Authors: Gan, Jing Yi, Chang, Lee Sin, Mat Nasir, Nur Athirah, Babji, Abdul Salam, Lim, Seng Joe
• Format: Article
• Language: English
• Subjects: Bioactivities; Drying; Glycoprotein; Hydrolysate; Viscosity
• ISSN: 0023-6438; 1096-1127
• DOI: 10.1016/j.lwt.2020.109777

Previous studies indicated that enzymatic hydrolysis of edible bird's nest (EBN) glycoproteins to glycopeptides resulted in higher bioactivities than raw EBN. However, a drying process is necessary to remove water after hydrolysis to increase the shelf-life and broaden its application. The current work was carried out to study the properties of EBN hydrolysates as affected by different drying methods: oven-drying (EBNod), spray-drying (EBNsd) and freeze-drying (EBNfd). The dried EBN hydrolysate yields were in the order of EBNfd > EBNod > EBNsd. Both EBNfd and EBNsd were relatively stable against microbial and biochemical changes as the water activity was below 0.60. Low lightness (L*), high yellowness (b*) and colour intensity (C) were obtained from EBNod, suggesting that the oven-drying had a negative effect on the colour appearance. EBNsd has a high soluble protein content (15.14 ± 0.56g/100g) and low viscosity (1.65 ± 0.17 mPa s), indicating high solubility when incorporated into food products as a functional ingredient. Besides, EBNfd exhibited a high degree of hydrolysis (45.09 ± 2.09%), essential amino acid content (42.62 ± 0.23g/100g), antioxidant activities [DPPH (60.80 ± 0.67%); FRAP (11.99 ± 0.29 mg TE/g)] and antihypertensive (75.76 ± 1.08%) activities. The FTIR spectrum showed that the powders exhibited similar functional groups. Freeze-drying of EBN with low-temperature exposure is preferable because it exhibits minimal effects on the properties of EBN hydrolysate. [Display omitted] •Freeze, spray and oven drying methods of EBN hydrolysate were compared.•Freeze dried EBN hydrolysates were has the highest yield at 82%.•Freeze-dried and spray dried EBN hydrolysates were stable microbiologically.•FTIR spectrum displayed similar functional groups for all the samples.•Freeze drying preserved the bioactivities of EBN hydrolysates.