Lipid Oxidation of Edible Peanut Pastes during Storage with Variation of Environmental and Processing Factors1,2

Abstract

Storage studies were performed for a period of 127 days to evaluate factors of processing and storage environments affecting rancidity development of peanut paste. Factors of milling (stone slab or plate-type attrition mill), ethylenediaminetetraacetic acid (none or with 100 ppm EDTA additions), oxygen (vacuum or atmospheric packaging), light (dark or fluorescent illumination) and temperature (4C or 45C) were incorporated into a 2(5–1) fractional-factorial design. Rancidity developments were monitored using thiobarbituric acid reactive substances (TBARS) number and peroxide values. Initially dominant, the positive effect of oxygen on peroxidation was subsequently outpaced by the effect of temperature. Throughout the study, the effect of temperature on peroxidation levels was consistently positive and statistically significant. Significant positive interactions of the two effects continued from the second week to the end of the first month and a late appearance of negative interactions between light and temperature were noted. Elevated levels of TBARS were shown after 8 weeks without consistent association to the particular design factors.