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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.

As stingless bee honey (SBH) is gaining in popularity in the Malaysian market, it is now prone to adulteration. The higher price of SBH compared to floral honey has led to the use of unusual adulterants such as vinegar and even floral honey to mimic the unique taste and appearance of SBH. Since the current AOAC 998.12 method fails to detect these adulterants as their δ13C values are in the range for C3 plants, untargeted 1H NMR metabolomics was proposed. Principal component analysis of SBH 1H NMR fingerprints was able to distinguish authentic SBHs from adulterated ones down to 1% adulteration level for selected adulterants. Discriminant analysis showed promising results in distinguishing the preliminary datasets of authentic SBHs from the adulterated ones, including discriminating SBHs adulterated with different adulterants derived from C3 and C4 plants. Hence, to assure any emerging adulterant can be detected, all 1H NMR regions should be considered.