Effects of Boiling Time and Digestion Simulation on Protein and Protein Hydrolysate Produced from Swiftlet Nest Species Aerodramus fuciphagus

Abstract

Edible swiftlet nest (ESN) with a diverse content of health benefits is produced from swiftlets of Aerodramus fuciphagus. The nest is produced using the swiftlet’s saliva which contains high glycoprotein. This study was conducted to produce ESN protein hydrolysate and further determine the effect of boiling time (0 - 180 minutes) and digestion process on ESN samples and ESN protein hydrolysate. The enzymatic hydrolysis process was carried out using alcalase enzymes to produce ESN protein hydrolysate. Digestive tests on the ESN protein and hydrolysates produced were carried out using the simulations of in vitro human digestive system. Results showed that with increasing boiling time up to 180 minutes, the peptide content produced from boiled raw ESN and ESN hydrolysate was significantly different (p<0.05), with the ESN peptide content from boiled raw ESN was observed to be higher than ESN hydrolysate. Furthermore, protein digestion results for ESN and ESN hydrolysate showed significantly different peptide content values (p<0.05), with ESN having the highest degree of protein hydrolysis at 96.55%; followed by ESN hydrolysate of 60 minutes (88.69%), 120 minutes (89.32%), and 180 minutes (89.81%) which did not differ significantly among the sample. The findings of this study showed that ESN has been actively degraded within 30 minutes of boiling as compared to ESN hydrolysate. The difference explains that the protein component of ESN hydrolysate has been extensively digested by the enzymatic hydrolysis reaction during the preparation of the hydrolysate. The in vitro digestion process showed that the ESN protein and its hydrolysate are food proteins that can be well-digested by the human digestive system.