Solubility and stability of rice husk extracts
Prior to formulation of cosmetics containing rice husks, solubility
and stability need to be evaluated to formulate the cosmetic
base. Rice husk extract with the best antioxidant activity and
highest active contents was further evaluated on miscibility in
glycerine and propylene glycol. The extract dissolved in propylene
glycol (þ4) better than glycerine (þ3). Furthermore, the extractwas
stable at several pH conditions and no precipitate was observed at
pH 4, 7 and 9 (Table 3).