Nofima Mat AS-Norwegian Inst. of Food, Fisheries and Aquaculture Research, Osloveien 1, NO-1430 As, Norway.
J Food Sci. 2009 Oct;74(8):S345-50. doi: 10.1111/j.1750-3841.2009.01303.x.
In this study, photooxidation of sour cream packaged in cups with different light barrier properties was investigated. The sour cream was light exposed for 36 h with a standard fluorescent light tube, simulating storage conditions in many Norwegian grocery stores. Three different cups were evaluated: a white cup, a cup with medium light barrier (LB), and a cup with high LB. The quality of the sour cream was evaluated by sensory analysis and front face fluorescence spectroscopy. The sour cream stored in white cups became very rancid during the light exposure, with a rancid flavor score of 7.8 on a scale from 1 to 9, where 9 is the highest intensity. Cups with high LB gave best protection against the light. The sensory assessors could not distinguish between sour cream stored in cups with high LB and sour cream stored in the dark. The rancid flavor intensity for the cups with medium LB was significantly different (P < 0.05) from both the white cup and the cup with high LB. The sensory flavor intensities indicated that with 36 h of light exposure, only a cup with high LB will protect the sour cream sufficiently. The fluorescence measurements corresponded well with the sensory analysis as the photosensitizers were somewhat degraded for sour cream stored in cups with medium LB and most degraded in the white cups. For the cups with high LB, the fluorescence peaks that originated from the photosensitizers were all intact.
Dairy products such as sour cream will develop off-odor and taste faults ("sunlight taste") in a few hours if exposed to sufficient fluorescent lightning in the grocery stores. A light barrier can be incorporated in the packaging material to protect the dairy products from the light. Our experiment showed that the incorporation of a black pigment into 1 of the 3 plastic layers in the cup for packaging of sour cream protected the sour cream from degradation when exposed to light.
本研究考察了不同光阻性能杯包装的酸奶油的光氧化情况。酸奶油用标准荧光灯管进行了 36 小时的光暴露，模拟了许多挪威杂货店的储存条件。评估了三种不同的杯子：一种白色杯子、一种中光阻（LB）杯子和一种高光阻（LB）杯子。通过感官分析和正面荧光光谱法评估酸奶油的质量。在光暴露过程中，储存在白色杯子中的酸奶油变得非常酸败，其酸败风味评分为 1 到 9 之间的 7.8，其中 9 为最高强度。高光阻杯对光的保护最好。感官评估员无法区分储存在高光阻杯和黑暗中的酸奶油。中光阻杯的酸败风味强度与白色杯和高光阻杯有显著差异（P < 0.05）。感官风味强度表明，经过 36 小时的光照，只有高光阻杯才能充分保护酸奶油。荧光测量与感官分析非常吻合，因为中光阻杯储存的酸奶油中的光增感剂略有降解，而白色杯子中的光增感剂降解最多。对于高光阻杯，源自光增感剂的荧光峰均完整无损。
如果乳制品（如酸奶油）在杂货店中暴露在足够的荧光灯下几个小时，就会产生异味和口感缺陷（“阳光味”）。可以在包装材料中加入光阻层来保护乳制品免受光线照射。我们的实验表明，在用于包装酸奶油的杯子的 3 个塑料层之一中加入黑色颜料，可以在暴露于光时保护酸奶油不降解。
