title: Effect of an oxygen scavenger on the stability of preservative-free flour tortillas.
abstract: Along with purge and moisture control, oxygen scavenging is a prominent active packaging technology employed by many food processors. The objective of this study was to determine the effect of an oxygen scavenger system (OSS) on the shelf life of preservative-free tortillas stored at varying storage conditions. The shelf life of the tortillas was evaluated at accelerated storage (AS; 37 °C, 75% relative humidity [rh]), room temperature (RT; 22 °C, 57% rh), and refrigeration (R; 4 °C, 42% rh) conditions. The OSS consisted of a multilayer, coextruded bag paired with an oxygen scavenger sachet. A resealable bag made of low-density polyethylene/linear low-density polyethylene was used as a control. The diameter, thickness, CIELab color, water activity, pH, texture, and microbial growth within the sample tortillas were measured before and after exposure to the storage conditions. The results showed that the OSS had superiority when compared to the control. The weight and thickness under RT remained unchanged, while lightness was superior to the control under R conditions. Under AS, gradient remained constant, and force followed the same pattern under RT and R conditions. At the same time, microbial growth as measured by aerobic plate count and yeast and molds showed no changes under both AS and RT conditions. Future studies will investigate the effect of a faster acting oxygen scavenger on shelf life of this type of tortillas.
  
  
  CONCLUSIONS
  The results of this study show promise for the use of oxygen scavenging technology in the packaging of natural and preservative-free tortillas.
authors: Chemistry Department, University of Southern California, Los Angeles, CA 90089, USA.
authors: Priscilla D
authors: PD
authors: Antunez
authors: María Botero
authors: MB
authors: Omary
authors: Kurt A
authors: KA
authors: Rosentrater
authors: Melvin
authors: M
authors: Pascall
authors: Lauren
authors: L
authors: Winstone
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D001420:Bacteria, Aerobic / Q000254:growth & development / Q000302:isolation & purification; D001939:Bread / Q000032:analysis* / Q000382:microbiology; D002140:California; D055598:Chemical Phenomena; D015169:Colony Count, Microbial; D003116:Color; D004032:Diet / Q000208:ethnology; D005433:Flour / Q000032:analysis; D005511:Food Handling; D018857:Food Packaging; D005658:Fungi / Q000254:growth & development / Q000302:isolation & purification; D006358:Hot Temperature / Q000009:adverse effects; D006813:Humidity / Q000009:adverse effects; D008422:Materials Testing; D055595:Mechanical Phenomena; D050296:Microbial Viability; D012034:Refrigeration; D014908:Triticum / Q000737:chemistry; D014867:Water / Q000032:analysis
chemical_list: D000975:Antioxidants; D014867:Water