Volatilomics for halal and non-halal meatball authentication using solid-phase microextraction–gas chromatography–mass spectrometry

Abstract The adulteration of beef meatballs with wild boar (Sus scrova) meat or chicken may be undertaken for economic reasons. This adulteration is a very sensitive issue, particularly for Muslim consumers, as the consumption of wild boar is strictly prohibited by Islamic law. This study aimed to discriminate volatile compounds in meatballs made from beef, chicken, and wild boar and mixtures thereof using solid-phase microextraction–gas chromatography–mass spectrometry (SPME/GC-MS) and multivariate data analysis. SPME is a non-destructive method for the extraction of volatile compounds and does not alter the original chemical composition of the volatiles. A validated partial least squares discriminant analysis (PLS-DA) model with three classes was used to uncover the discriminating volatiles of each type of meatball. The results indicated that β-cymene, 3-methyl-butanal, and 2-pentanol were among the positive discriminating volatiles with the highest variable importance in projection (VIP) values among the chicken meatballs. The highest VIP positive discriminating volatiles in the beef meatballs were 5-ethyl-m-xylene, benzaldehyde, and 3-ethyl-2-methyl-1,3-hexadiene. The mixed meatballs exhibited an interesting profile, with all appearing in the same group as the pure wild boar meatballs. However, the discriminating volatiles derived from a separate PLS-DA model indicated that they contained different compounds. In the pure wild boar meatballs, six compounds (pentanal, 2,6-dimethylcyclohexanone, 1-undecanol, cyclobutanol, 2,4,5-trimethyl-thiazole, and 5-ethyl-3-(3-methyl-5-phenyl pyrazol-1-yl)-1,2,4-triazol-4-amine) were identified as discriminating volatile compounds with the highest VIP values. These compounds were consistently found as significant discriminating volatile compounds in mixture meatballs group although with different VIP value. This research demonstrated that SPME-GC/MS combined with multivariate data analysis was a fast and reliable method for differentiating meatballs made from beef, chicken, and wild boar meat based on their volatile compound contents.