Detection of adulteration activities in edible bird's nest using untargeted 1H-NMR metabolomics with chemometrics

Edible bird's nests (EBNs) are the nests of swiftlets, made from the saliva of the male swiftlet (Aerodramus fuciphagus). Due to their nutritional value, EBNs are recognized as a premium food and highly in demand among the Chinese community. EBNs are commonly adulterated with cheaper ingredients and efforts are being made to combat these activities using different analytical techniques. In this study, nuclear magnetic resonance (1H-NMR) metabolomic fingerprinting combined with chemometrics, particularly principal component analysis (PCA) and orthogonal partial least square-discriminant analysis (OPLS-DA), was employed to detect adulteration in EBNs. Authentic EBN samples from different locations in Malaysia were used and adulteration was simulated using nutrient agar, collagen, gelatine, karaya gum and melamine at 1, 5 and 10% w/w, respectively. Overall, unsupervised PCA was able to distinguish authentic EBNs from those adulterated with nutrient agar, collagen and gelatine down to 5% w/w adulteration level. As for EBN adulterated with karaya gum and melamine, a distinct peak can be observed at 1.91 ppm and 6.10 ppm, respectively. The supervised OPLS-DA predictive model was able to differentiate authentic EBNs from simulated adulterated EBNs with 100% accuracy. Conclusively, 1H-NMR metabolomics combined with chemometrics could be a potential tool for the detection of adulteration in EBN.