44F-19 |
Oxidative rancidity of peanut butter slices under different packaging and atmospheric conditions |
M. ADHIKARY1, D. D. Bellmer, and G. Brusewitz. (1) Biosystems Engineering, Oklahoma State University, 209 Ag Hall, Stillwater, OK 74078 Peanut butter, as marketed today in jars, is less convenient than other ready-to-eat products. Development of individually-wrapped peanut butter slices is in progress. Because peanut butter contains a substantial amount of fat, and fat is prone to oxidation, the packaging of the new product is critical for prevention of rancidity. Further investigation of the effects of packaging and storage conditions on the oxidative stability of peanut butter slices is necessary. This project involved shelf-life studies to investigate the oxidative rancidity of peanut butter slices with different types of packaging and under different atmospheric conditions of temperature and humidity. Two different tests were conducted to determine the degree of rancidity of the peanut butter slices: the peroxide test, and the Thio-Barbituric Acid (TBA) assay. The tests were carried out over six months under four different atmospheric conditions: room temperature and humidity (25C, 45% RH), refrigeration temperature (4C), elevated temperature (40C), and high temperature and relative humidity (40C, 80%RH). Four different packaging materials with a wide range of oxygen and moisture permeabilities were selected for use, including one of the common films used for packaging individually-wrapped cheese slices. From the experiments, rancidity seemed to develop in most packages after 1 ½ to 2 months of storage at high temperature conditions, and after about 4 to 5 months at refrigeration conditions. It was found that high temperature affected oxidative rancidity to a greater degree than high humidity. Also, the packaging materials with low oxygen permeabilities performed better than those with high oxygen permeabilities, whereas the moisture permeability of the material did not seem to affect rancidity. These results suggest that storage of the product at lower temperature and use of a plastic film with high oxygen barrier may greatly enhance the shelf life of the peanut butter slices.
Session 44F, Product Development
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