Degradation quality of reused palm cooking oil during storage: Case study in fried shallot industry

Frying process in a fried shallot industry usually is carried out by deep fat frying. This method involves the use of much oil and repeatedly uses and storages. This practice will decrease the quality of oil and even the fried product. The objectives of this research were to measure the quality degradation rate of use cooking oil repeatedly during storage and to calculate the efficiency of zeolite to adsorb the impurities of the reused cooking oil. The Oil quality was based on the National Standard of Indonesia (SNI 7709:2012). The quality parameters observed in this research were water and evaporated material content, free fatty acid value, and peroxide number. Based on the results of this research, it was found that the oil still meets the quality standard until the 5^th frying without storage. In this stage, the oil exposed the rate of degradation in water and evaporated material content, free fatty acid value, and peroxide number as 0.0046; 0.0878, and 0.303 respectively. The content of water, moisture and oxygen were the main cause of quality changes in cooking oil. The effort has been done to improve the quality of reused cooking oil by zeolite adsorption. Efficiency values obtained from this process by moisture and evaporated material content, free fatty acid value, and peroxide number was 8.20%; 52.38%; and 30.95% respectively.