EFFECT OF NAVY BEAN HULL EXTRACT ON THE OXIDATIVE STABILITY OF SOY AND SUNFLOWER OILS

The effectiveness of freeze-dried navy bean hull extract (NBHE) as an antioxidant was evaluated in storage studies with soy and sunflower oils. Monthly peroxide value (PV) determinations indicated NBHE to be a stronger antioxidant than butylated hydroxyanisole-butylated hydroxytoluene (BHA-BHT) mixture and rosemary AR but was less effective than tert-butylhydroquinone (TBHQ) at all levels (100, 500, and 1000 ppm) and storage conditions (26 and 37-degrees-C). At the 100 ppm level, NBHE-treated soy oil attained a PV of 25.4 mequiv/kg at 37-degrees-C in 9 months, while the control oil sample had a PV of 62.0 mequiv/kg at the same period. At 26-degrees-C, the same concentration of NBHE lowered the PV of soy oil to 14.8 mequiv/kg compared to a PV of 32.7 mequiv/kg attained by the control oil sample for 12 months under the same condition. Similar pattern of PVs were observed in sunflower oil treated with NBHE and stored under the same temperature conditions.