| Summary: | Edible Bird’s Nest (EBN) has been regarded as one of the most valuable functional foods and traditionally used for the treatment of various diseases including diabetes, hypertension, and gastrointestinal problems. Previous research has shown that EBN is rich in glycoproteins and enzymatic hydrolysis can enhance the bioactivity of EBN due to the release of functional peptides and sialic acid. However, hydrolysed EBN in liquid form is thermally unstable and further processing into dried powder is often necessary for easier product handling and shelf stability. Although there are many studies conducted on the bioactivities of raw or hydrolysed EBN, so far, the comparison of the bioavailability and characteristics between liquid and dried hydrolysed EBN is still lacking. Hence, this study aims to compare the bioactivities (antidiabetic and antihypertensive activities) of hydrolysed EBN before (EBNLIQUID) and after (EBNPOWDER) drying. In addition, the safety and digestibility of hydrolysed EBN were also investigated. Spray drying was selected due to its feasibility and ability to retain the bioactive compounds in EBN hydrolysate. The EBN samples were tested for their antidiabetic activity using α-amylase inhibition assay whereas antihypertensive activity was evaluated using angiotensin converting enzyme inhibition (ACE-i) assay. Cytotoxicity and digestibility were determined by using MTT assay and simulated in vitro digestion, respectively, while the stability was evaluated in terms of the degradation of sialic acid and antioxidant activity over time. EBNLIQUID showed higher (p<0.05) (IC50 = 229.25 ± 0.45 μg/mL) antidiabetic activity compared to spray dried EBNPOWDER (IC50 = 459.30 ± 0.24 μg/mL) while for antihypertensive activity, the reversed result was observed where EBNPOWDER possesses higher inhibitory activity towards ACE than EBNLIQUID with IC50 of 295.18 ± 0.74 μg/mL and 565.42 ± 0.45 μg/mL respectively. Moreover, for viability, at higher concentrations (3000 μg/mL), both EBNLIQUID and EBNPOWDER exhibited an inhibitory effect on cancer cell growth, while for digestibility, total amino groups released by EBNLIQUID was higher (52.23 ± 2.35 μmol/mL) compared to EBNPOWDER after intestinal digestion which proved that EBNLIQUID shows better digestion compared to EBNPOWDER. Meanwhile, in term of stability, EBNPOWDER demonstrated lower reduction rate with time for antioxidant activity and sialic acid content compared to EBNLIQUID. The half-life (t1/2) of EBNPOWDER for antioxidant activity and sialic acid at temperature 4 ± 4°C are 187.34 and 266.60 days respectively, longer than EBNLIQUID, indicating a prolonged shelf life and greater stability of the dried powder. This study shows that both EBNLIQUID and EBNPOWDER might be regarded as a source of natural antioxidants and sialic acid with antidiabetic and antihypertensive properties which can be beneficial for human health. The beneficial effects of enzymatic hydrolysis and spray drying method suggest future exploration of the EBN hydrolysate as a possible nutraceutical dietary supplement.
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