5.5. Residual compound quantification in foodstuffs
The quantification of the residual content of antimicrobials in a food matrix denotes another means of evaluating the migration and incorpo- ration of active compounds into food. Still, as well as commented for sensory assays, there are only a few reports on antimicrobial emitting sachets that consider this important factor.
Otoni et al. (2014b) quantified the residual AITC content in peanut grains throughout 90 d of storage. The antimicrobial was extracted from peanut grains with n-hexane and analyzed by gas chromatogra- phy. In this work, no residual AITC was detected in peanuts, and this finding was attributed to the high volatile profile of the active compound, allowing the liquid AITC that diffused into peanut grains to volatilize. According to the authors, this eliminates the risk of AITC intake by consumers and is desirable to offset its strong taste.
Passarinho et al. (2014) quantified the residual oregano EO content in bread by stirring bread samples at 80 °C for 20 min in 20-mL vials. Gaseous aliquotswere analyzed through gas chromatography and com- pared to a standard curve of γ-terpinene and ρ-cymene, precursors of thymol and carvacrol, the major components in oregano EO. The contents of both compounds were found to increase with storage time, corroborating the active role that the tested sachets played by gradually releasing antimicrobial compound to a food matrix.
The residual contents of active compounds should be studied more frequently and also correlated with sensory tests. This correlation would allow understanding consumers' sensorial perception and pref- erence, and acceptance thresholds could be determined and associated to residual concentrations.