Formulation of Food-Grade Grease Using Paraffin Oil, Fumed Silica, and Chitosan

Abstract

Three formulations intended for NSF H1 food-grade grease were prepared in this study comprising paraffin oil as a base oil and fumed silica as a thickener. No additive was added in formulation 1 (F1) and formulation 2 (F2), whereas chitosan was added in formulation 3 (F3) as an additive. A commercial food-grade grease (FGG) was used for comparison purposes. The formulated greases and the commercial FGG were characterised for thermal stability via thermogravimetric analysis (TGA) and derivative thermogravimetric analysis (DTG). Fourier-transform infrared (FTIR) spectroscopy, dropping point, oil separation, and consistency tests were also carried out to evaluate the properties of the greases. The FTIR spectra were obtained for the fresh and aged greases for grease characterisation. The results showed that the grease made with chitosan as an additive demonstrated higher oil separation, better consistency, and was less affected by ageing, as indicated by the change of grease colour after the oil separation test. F1, F2, F3, and the commercial FGG recorded dropping points higher than 350 °C, indicating no dropping point properties for the tested greases. The grease formulated with chitosan (F3) achieved the highest oil separation with 1.21%, while the commercial FGG recorded the lowest oil separation with 0.66%, followed by F1 and F3 with the oil separation of 0.99% and 0.98%, respectively. For the consistency test, the NLGI number for each formulation varied but the commercial FGG showed the lowest NLGI number of 2, whereas F3 showed the NLGI number in the range of 2–3, and F1 showed the NLGI number of 3. The aged grease of F3 had unchanged consistency after the oil separation test. Based on the results, the formulated greases have acceptable properties in comparison to the commercial FGG, and the addition of chitosan contributes positively to the grease characteristics.