Inhibition of lipase activity in commercial rice bran of coarse, fine, and superfine cultivars

Lipase activity of commercially produced rice bran was inhibited with an aim of multiple product recovery. The initial values of free fatty acid were 8.72, 1.89, and 4.41% in bran from coarse, fine, and superfine cultivars which increased to 60.11, 51.70, and 75.33% level, respectively, after 40 days of ambient storage conditions. Storage temperature of −20°C and hydrochloric acid at 5% were found to be effective in controlling the lipase activity. Sodium hydroxide was less effective in controlling the lipase activity even at 10%. Hydrogen peroxide (30%) did not inhibit the activity but promoted oil degradation in rice bran. The initial peroxide value varied from 2.74 to 4.76 meq O2 per kg of oil which increased to 10.19–14.15 meq O2 per kg in untreated, while HCl-treated samples varied from 6.22 to 7.98 meq O2 per kg at 5% level after 40 days.