title: Improvements in the shelf life of commercial corn dry masa flour (CMF) by reducing lipid oxidation.
abstract: To improve the shelf life of commercial nixtamalized corn dry masa flour (CMF), the modified atmosphere packaging (MAP) was used. Pouches (20 × 20 cm) of ethyl vinyl alcohol (EVOH) with 180 g of CMF were stored at 55 °C, and a(w) of 0.45; under Light and Dark conditions, antioxidants (0.02% TBHQ), Vacuum, and N(2) and CO(2), and used as treatments. Thereafter, changes in their linoleic acid (LA) concentration by GC, peroxide (PV), and anisidine values (p-A), which were monitored for 180 d. EVOH showed a significantly lower consumption of LA by autoxidation (11.7% ± 0.2% in 117 d) than polyethylene film (70.5% ± 0.3% in 113 d) under the same storage temperature. The elimination of oxygen by vacuum in each pouch allowed a low consumption (16.4% ± 0.1%) of LA. PV (14.5 ± 0.09 mEq/kg of fat), and p-A (63 ± 0.16 mmol/kg) were low, and generated over 121 d of storage. CMF stored under MAP had 100% protection against oxidation of LA.
  
  
  CONCLUSIONS
  A combination of Vacuum and EVOH packaging extended the shelf life of CMF to 108 d with only 10% of LA loss. For retail stores, the EVOH packaging will reduce lipid oxidation of CMF and safety related to off odors and flavors from the oxidation of tortillas will increase dramatically.
authors.affiliation: Inst Tecnológico Agropecuario ITA 121, Block 611, Valle del Yaqui, Apdo, Postal 797, Cd Obregón, Sonora, Mexico.
authors.forename: A
authors.initials: A
authors.lastname: Márquez-Castillo
authors.forename: R L
authors.initials: RL
authors.lastname: Vidal-Quintanar
mesh_terms: D000975:Antioxidants / Q000378:metabolism; D002245:Carbon Dioxide / Q000378:metabolism; D015169:Colony Count, Microbial; D005433:Flour; D018857:Food Packaging / Q000379:methods*; D005519:Food Preservation / Q000379:methods*; D019787:Linoleic Acid / Q000032:analysis; D015227:Lipid Peroxidation; D009584:Nitrogen / Q000378:metabolism; D009812:Odorants; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism; D013649:Taste; D013696:Temperature; D014618:Vacuum; D003313:Zea mays / Q000737:chemistry*; D017962:alpha-Linolenic Acid / Q000032:analysis
chemical_list: D000975:Antioxidants; D017962:alpha-Linolenic Acid; D002245:Carbon Dioxide; D019787:Linoleic Acid; D009584:Nitrogen; D010100:Oxygen