2001 AACC Annual Meeting Charlotte, North Carolina October 14-18, 2001 Charlotte Convention Center

Pouches (20 × 20 cm) of ethyl vinyl alcohol (EVOH) were used to stored corn flour at 55°C and 0.45 constant water activity. Different condition of light, antioxidants (0.02% w/w of TBHQ), vacuum, and modified atmoshere packing (MAP) with carbon dioxide and nitrogen were used to measured the rate of lipid oxidation of the stored corn flour. Gas chromatography (GC) and chemical analysis (peroxide, PV, and anisidine values, AV) were used to obtain the oxidation ratios over the storage time. Corn flour increased its shelf life proportional to the level of protection against lipid oxidation. Flours stored in EVOH presented a significantly lower consumption of linoleic acid in autooxidation (11.7% in 148 days) than flours stored in a polyvinyl film (70.5% in 113 days) under same storage conditions. Flours stored under lack of light presented the highest values for chemical methods, PV (16.1 meq/kg fat) and AV (66.8 mmol/kg); followed by the flours with TBHQ (PV=12.9 meq/kg) and AV=63.3mmol/kg). The elimination of oxygen by vacuum in each pouch of corn flours allowed only 9.1% of consumption of linoleic acid by autoxidation, with a low profile of PV (14.5 meq/kg) and AV 63 mmol/kg) generated over 120 days of storage. Corn flour stored under MAP had 100% protection against lipid oxidation of linoleic acid. A combination of vacuum and EVOH packing offered to corn flour an extension of 260% of the shelf life observed in pouches of polyvinyl.