Evaluation of Fluorescent Light on Flavor and Riboflavin Content of Milk Held in Gallon Returnable Containers

Abstract

Five 1-gal. retail containers were evaluated for their protection of homogenized milk against development of light-induced flavor and degradation of riboflavin. These were clear polycarbonate, tinted polycarbonate, high-density polyethylene, and glass returnable containers and an unprinted fiberboard non-returnable container. All containers were held in a commercial sliding door display case at 7 ± 1 C illuminated to 1076 lx with a fluorescent lamp up to 72 h. Sensory evaluation was conducted by a trained panel using hedonic 9-point scoring and magnitude estimation scale techniques. Riboflavin was determined by the fluorometric method. An evaluation of the containers demonstrated that there was a significant difference (P < .05) in preference and degree of light-induced flavor between the milk held in clear polycarbonate and glass compared to the control milk after 12 h of exposure. Milk held in high-density polyethylene was significantly different in preference from the unexposed control following 12 h when evaluated by the hedonic method; however, 24 h of exposure were needed to demonstrate a significant difference in the degree of light-induced flavor using the magnitude estimation technique. The tinted polycarbonate container, which is fabricated with a blocking agent that inhibits transmission of light at 380–480 nm, provided the milk with greatest protection of the returnable containers against development of the off-flavor. Milks exposed in fiberboard and also milks in the five containers held in the dark were not significantly different from the unexposed control. The milks held in glass demonstrated significant losses in riboflavin following exposure.

Controlling Light Oxidation Flavor in Milk by Blocking Riboflavin Excitation Wavelengths by Interference

“…On all days, the 400 nm block treatment was either similar or significantly higher in light‐oxidized flavor than the 446 nm block treatment. These findings are in agreement with a number of researchers (Herreid and others 1952; Bradfield and Duthie 1965; Hoskin and Dimick 1979; Nielsen 1999; Van Aardt and others 2001) who found that blocking wavelengths between 380 and 500 nm gave greater protection against light oxidation flavor than blocking other wavelengths. It also indicates that blocking 446 nm is important in reducing light oxidation flavor, since both the 400 and 570 nm block treatments, which also transmit this wavelength but at a higher percent transmission, tended to be higher in light oxidation flavor than the 446 nm block treatment.…”

“…Two important factors affecting the development of light‐oxidized flavor in milk are light wavelength and packaging material. Many researchers have shown that exposure to visible light between 365 and 500 nm causes a significant increase in light oxidation in milk (Herreid and others 1952; Bradfield and Duthie 1965; Sattar and others 1976a; Hoskin and Dimick 1979; Bosset and others 1995; Nielson 1999; Hansen and Skibsted 2000; Lennersten and Lingnert 2000; van Aardt and others 2001). Riboflavin is implicated in this oxidation because it acts as a photosensitizer when exposed to specific wavelengths (400, 446, and 570 nm) within this range (Sattar and others 1977; Bekbolet 1990).…”

Off-Flavors of Dairy Products

“…Organoleptic differentiation of the light-induced and metal-induced oxidized flavor defect is difficult. Hoskin and Dimick (41) Dimick ( 3.2.2 Flavor Development.…”

Photodegradation of Foods and Beverages

“…This could be of considerable nutritional importance, since milk contributes 40-50% of the dietary riboflavin in the United States and in many other Western countries. For example, milk in 3-quart plastic jugs lost approximately 12% of its riboflavin content after 12 h of exposure to 2200 Ix of cool white fluorescent light; over 18% was lost in smaller plastic pouches of milk (deMan, 1978;Hedrick and Glass, 1975;Hoskin and Dimick, 1979). The riboflavin in milk disappears on illumination in a first-order process with an activation energy of 8 kcaljmol (Singh et 01., 1975;Allen and Parks, 1979); the rate of loss is greater in skim milk than in whole milk.…”

“…Loss of quality is most rapid for milk in clear glass and polycarbonate containers. and is almost as fast in polyethylene jugs; the use of standard and opaque cardboard containers gives almost complete protection against light (Bray et 01., 1977;Anonymous, 1978;deMan, 1978;Hoskin and Dimick, 1979). Short-wavelength UV radiation is used to irradiate milk for the production of vitamin D; this process must be used with care since radiation in this wavelength range produces off-flavors and destroys certain nutrients (Sattar and deMan, 1975).…”