Storage stability of margarine

ABSTRACT STORAGE STABILITY OF MARGARINE MASKAN, MEDENİ M.Sc. in Food Eng. Supervisor: Assoc. Prof. Dr. Mehmet D. ONER January 1992, 99 pages In this study, Rancimat Method, which is one of the Accelerated Shelf -Lif e Test (ASLT) methods, was used to predict the shelf -lif e of margarines, and two margarine samples (packaged with parchment (A) and plastic (B) ) were studied to predict their storage stabilities. The samples were stored at two different temperatures (4°C with a 35 % relative humidity and 14 °C with 70, 85 and 98 % relative humidities). The parameters, peroxide value (PV), free fatty acid (FFA) and total mold and yeast count, that affect margarine deterioration were studied at the mentioned conditions above. The shelf-lives that obtained from ASLT results by extrapolation to low temperatures were 134 and 77 days for Margarine (A), and 125 and 63 days for Margarine (B) at 4 and 14 °C respectively. Q10 values calculated from ASLT results, based on formic acid formation, were 2.05 and 2.10, and from normal storage results, based on peroxide formation, were 1.33 and 1.34 for Margarine (A) and (B) respectively. iiiNo hydrolytic deterioration was observed on both Margarine (A) and (B). Also, there were no mold and yeast growth on Margarine (B) neither at high nor low relative humidities. But, mold and yeast growth was observed after 73rd day at 98 % R.H. and 90th day at 85 % R.H. for Margarine (A). It was observed that parchment packaged Margarine (A) deteriorated in a shorter time than plastic packaged Margarine (B) at R.H. above 70 %. The shelf-life of Margarine (A) was ended due to microbial growth. On the other hand, there was no microbial growth in Margarine (B), therefore, its shelf-life at high R.H. ended due to oxidative rancidity. It was concluded that Tangent Line Method is a healthy method to decide the end of shelf-life of a fat containing food product. Key words: Margarine, Accelerated Shelf -Lif e Test, Storage Stability, Rancidity, Peroxide Value, Free Fatty Acid, Microbial Count, Rancimat. iv