MIR-ATR Spectroscopy as a Rapid Technique for Edible Birds Nest Authentication

Edible birds nest (EBN) is widely consumed as a health food product. In recent years, adulteration of EBN is quite familiar due to high economic value and limited supply of natural authentic EBN. Authentication and assessment of EBN quality demands highly labour cost and time consuming sequential analytical measurements to confirm that the product quality meets technical and regulatory requirements. Mid-Infrared - Attenuated Total Reflectance (IR-ATR) spectroscopy is used in this study as an alternative approach to conduct rapid, cheap and non-destructive spectroscopic measurements. The samples used were authentic processed EBNs of different grades (2A, 3A, 4A and 5A) from the swiftlet species Aerodramus fuciphagus supplied by Ministry of Health, Malaysia. Similarly, adulterants commonly used in EBN namely agar, Karaya gum, bovine gelatine, fish gelatine, melamine and porcine collagen were also characterized. Adulterant mixtures were prepared gravimetrically at concentrations of 1, 5 and 10% m/m by combining appropriate quantities of adulterants with an authentic EBN sample. The samples then were analysed by the IR-ATR spectroscopy. The results showed 50 % of the EBN samples were adulterated at 5 and 10 % w/w level. This included the common adulterant Karaya gum, porcine gelatine and melamine. The analysis was less sensitive toward bovine gelatine only detecting the 10% w/w adulterated level and the fish gelatine was not detected at the 1, 5 or 10% w/w level. The IR-ATR spectroscopy technique is useful tool and rapid technique for the authentication of EBN produced in Malaysia. Further work is required to validate the approach for a wider range of adulterants including flavour enhancers and preservatives. (author)