Optimization of neutralization parameters in minimal refining process of sunflower seed oil

Abstract

Crude sunflower oils are subjected to traditional refining process to eliminate undesirable components such as gums, free fatty acids, and oxidative products. However, some desirable minor compounds are also removed or reduced during refining operations such as tocopherols and phenolic components. Approach to retain desirable minor components can include alternative refining ways that can both decrease refining steps and provide milder processing conditions. The overall objective of the study was to produce neutralized sunflower oil using Ca(OH)2, MgO, and Na2SiO3 as an alternative to strong alkali (NaOH) which is used in conventional neutralization and to optimize these alternative neutralization compounds by evaluating their effectiveness by response surface methodology. The estimated optimal parameters for neutralization of sunflower seed oil were Ca(OH)2 at 0.30%, 53.0°C, and 19.7 min; MgO at 0.38%, 57.6°C, and 17.8 min; and Na2SiO3 at 0.81%, 55.7°C and 19.1 min. Novelty impact statement Minimal refining of vegetable oils is a new approach (from the idea that “Less-processed oils are healthier having higher nutritional value than refined oils”) that aims at the retention of desirable minor components. This work provides detailed research to produce minimally neutralized sunflower seed oil using weak alkalis such as Ca(OH)2, MgO, and Na2SiO3 as alternatives to sodium hydroxide used in conventional neutralization. The study revealed that refining of oils by Ca(OH)2 had the lowest FFA and highest α-tocopherol content than other weak alkalis.