Controlling Light-Induced Flavors in 2% Milk

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Virginia Tech

Energy regulations have shifted commercial retail cases from fluorescent to light emitting-diode lights (LED), however the effect of LED light on milk quality (flavor and nutritional content) has not been thoroughly studied. Packaging efficacy of light protecting additives (LPA) in high-density polyethylene (HDPE) was studied for protection against light-induced oxidation of high-temperature short-time (HTST) 2% milk under fluorescent (1882±993 lux) and LED light (915±150 lux). Milk quality measures included oxidation level, riboflavin (Rb) retention, headspace volatiles, and sensory evaluation were analyzed to determine the interaction between light source, packaging material, and storage time. HDPE packaging included translucent package (0% TiO2) serving as control (light-exposed, light-protected: foil and plastic overwrap) and three LPA packages (low (1.3% TiO2), high (4.9% TiO2), yellow). Rb concentration decreased among all packages (40%-60%) after 72h for both lights. Volatile aldehydes (TBARS), increased in all packages (23%-82%) during storage over 72h at 4C. Sensory evaluation (triangle test) revealed detectable flavor changes at a TBARS value of 0.11 mg/L; LPA packages saw this change starting at 4h and continued through 72h. The high package protected milk flavor effectively at 4h under fluorescent light; yellow package was effective for 4h under LED light. Despite detectable sensory differences, acceptability scores (9-point hedonic scale) were significantly greater for milk exposed to LED light in light-protected and high packages (p<0.05). We conclude that LED light may be less harmful to milk flavor vitamin content, but packaging needs to be improved to maintain milk's ideal flavor past 4h of light exposure.

milk, Oxidation, sensory, packaging