Abstract:

Soybean oil was bleached by using activated clay and attapulgite clay together in different ratios. One-factor-ata-
time experiments and Freundlich equation were adopted to optimize the decolorization process. The optimal conditions
for decolorizing soybean oil were established by adding 1.9 g/100 mL of a mixture of activated clay and attapulgite clay at a
ratio of 2:3 to soybean oil and then incubating at 110 ℃ for 40 min. Under these conditions, the decolorization efficiency of
soybean oil was 85%. The absorbance of soybean oil samples decolorized with different ratios of activated clay to attapulgite
clay was compared with each other after heating treatments at 105 ℃ for different durations. The results observed showed
that increasing the proportion of attapulgite clay when the total amount of adsorbents was kept at 1.7 g/100 mL stabilized oil
lipids and hence avoided color reversion.

Key words: soybean oil, Freundlich equation, bleaching, color reversion