Some factors pertaining to the packaging of shortening in glass

Summary 1. Even light of very high intensity has no significant effect on the peroxide development of “white” all-hydrogenated vegetable shortenings. Strong light, however, does cause a flavor and odor change which is not characteristic of rancid fat. 2. When determining the effect of light on shortenings in the laboratory, it is essential that the artificial light source have very nearly the same energy distribution characteristics as solar light, at least down to 325 millimicrons. 3. Light between 325 and 500 millimicrons is more effective in promoting an odor and flavor change in “white” shortenings than longer wave lengths. 4. Certain amber colored glass jars almost completely nullify the influence of light on the flavor and odor. Green and blue colored jars are helpful, but much less so than amber jars. Although appearing substantially opaque, opal glass jars are of little value in minimizing the effect of light. 5. Even strong light modifies the absorption properties of liquid “white” shortening very little in the ultraviolet and visible ranges. 6. Air-blowing liquid “white” shortening at an elevated temperature causes the absorption to increase perceptibly in the blue end of the visible range, but has no significant influence on the absorption in the ultraviolet portion.