Abstract #T196

# T196
Chemosensory analysis of light-emitting diode and fluorescent light on fluid milk volatiles.
Kemia N. Amin*1, Maria A. Hadley1, Susan E. Duncan1, Kumar Mallikarjunan1, 1Virginia Polytechnic Institute State University, Blacksburg, VA.

Fluid milk deteriorates rapidly under lighted storage, affecting milk sensory and nutritional quality before purchase. Energy conservation efforts have shifted commercial retail cases from fluorescent to light emitting diode lights (LED). The effect of LED lights on milk quality has not been determined. Efficient milk freshness validation methods are needed in the dairy industry to predict sensory quality. The purpose of this study was to determine volatile differences of 2% milk under LED and fluorescent lights using a commercial conducting polymer electronic nose (ENose). This study focused on changes in volatiles within 72 h of storage under refrigerated retail case conditions. Fresh 2% milk (half gallon high density polyethylene; n = 60) was purchased from a local grocery store immediately upon delivery. Bottles (treatments: light protected control [LP; foil overwrap); light-exposed (LE)] were randomly placed in a commercial retail case with LED and fluorescent lighted sections. Milk was tested on receipt and at 4, 8, 24, 48, and 72 h. Samples (n = 3 bottles per LP and LE treatment) were collected at each time interval and tested with the ENose and thiobarbituric acid reactive substances (TBARS). Canonical distribution (P < 0.05) of volatile changes showed 100% separation of volatiles components detected by ENose, for each time under each light treatment for LE milk compared with LP control. As time increased, separation between LED and fluorescent clustered ENose data moved further away from the control and each light treatment resulting in greater differences. By 72 h, LED LE cluster data were farther from the ideal fresh milk than the fluorescent cluster. This suggests that milk under LED may have more differences in volatiles than milk under fluorescent light at 72 h. TBARS values were not significantly different (P > 0.05) between the interval light treatments. ENose technology could be more sensitive to volatile changes than TBARS. The volatile differences detected through the ENose may affect product integrity and consumer response. Understanding different light effects on milk and ENose application in the dairy industry could improve sensory and quality testing of milk.

Key Words: electronic nose (ENose), milk, light oxidation