Author : Siriporn Chaemsanit … [et al.].

Source : Journal of Food Science 84(4)2019:798-806

Abstract : The aim of the study was to control the release of peppermint oil (700 µL/L) by coating activated carbon (AC) contained in sachets with different solutions (tapioca starch, corn starch, gelatine, carnauba, paraffin, and mixed carnauba–paraffin) for inhibiting the growth of Aspergillus flavus on brown rice (BR). Paraffin‐coated AC with adsorbed peppermint oil was then applied to extend the shelf life of BR during long‐term storage (60 days) at 30 ± 2 °C. The mechanism of peppermint oil vapor release in this system was also studied using GC–MS. The result revealed that paraffin‐coated AC with adsorbed peppermint oil present in sachets showed the highest antifungal activity against A. flavus growing on the surface of BR. In addition, paraffin‐coated AC with adsorbed peppermint oil could prolong the shelf life of BR from 10 days (control) to at least 60 days under tropical climatic conditions. Moreover, storage of BR in the presence of sachets containing paraffin‐coated AC with adsorbed peppermint oil at a concentration of 700 µL/L revealed no significant effects on major rice quality‐related factors, such as moisture content, color, water uptake percentage, and gelatinization temperature. Peppermint oil component analysis by GC–MS indicated that paraffin could trap some minor components of peppermint oil and allow the major components such as menthone, menthol, and alpha‐pinene, which are compounds that play an important role in mold growth inhibition, to be exposed to air. Thus, this research demonstrated the potential of paraffin‐coated AC containing adsorbed peppermint oil for controlling the growth of molds during prolonged rice storage.

Subject : Activated carbon. Brown rice. Mold. Peppermint oil. Releasing mechanism.