A rapid technique to determine purity of edible bird nest

Abstract

Edible bird nest (EBN) is a gelatinous substance produced by different species of swiflets during the breeding season. It is widely consumed as a health food product for its high beneficial effects to human being. In recent years, adulteration of EBN is quite common, due to the high economic value and limited supply of natural authentic EBN. The compositional properties such as protein, carbohydrates, fat content and moisture were determined. The samples used were raw unprocessed EBN and of different grades (2A, 3A, 4A, 5A and biscuit white) processed EBN samples from the swiftlet species Aerodramus fuciphagus. Similarly, adulterants commonly used in EBN, namely agar, starch, sodium alginate, carrageenan, pork skin and egg white were also characterized. In both the raw and processed EBN samples the presence of similar compounds such as hydroxy, carboxyl, carbonyl, aryl, amines, alkynes, and nitro groups were detected. FTIR spectrum of the raw unprocessed EBN was identical to that of the spectra of processed EBN samples. The spectra of the pure adulterants were different from that obtained in EBN samples. The spectra of adulterated EBN samples with addition of the adulterants were apparently different from that of processed EBN. The fingerprint region of the spectra of pure edible bird and adulterated edible bird nest samples were different at <1700 cm-1. The NH group was absent in all the adulterants except in pork skin and egg white. Interestingly, only pork skin has ester C=O stretch bond and C=CH group which were not present in EBN itself and in other adulterants. Hence, the EBN samples could be proven authentic and labeled as halal products using FTIR technique. The highest component found in EBN samples was protein (58.31-63.88%), followed by carbohydrate in the range (11.3-12.9%). The amount of moisture content is within the range of 7.0-9.34% and fat of 0.05-0.09%. The protein and carbohydrate contents of EBN are normally high. The FTIR technique is a useful tool and rapid technique for the determination of purity of EBN and thus as a deterrent to the commercial adulteration of EBN based products.