Deep-fried keropok lekors Increase Oxidative Instability in Cooking Oils

Summary of article contents:

Introduction

Deep frying is a common cooking method that subjects oils to high temperatures, leading to chemical reactions such as oxidation, hydrolysis, and polymerization. These processes can negatively alter the properties of the oils, producing harmful products. This study investigates the impact of repeatedly heating palm and soybean oils on their oxidative quality when used to fry traditional Malaysian snacks, keropok lekors and potato chips, emphasizing the health implications of consuming these oils in various conditions.

Effect of Heating on Oil Quality

The research found that the frequency of heating the oils significantly increased their peroxide values, indicating higher levels of oxidation. For instance, palm oil that had been fried five times recorded a peroxide value of 14.26 meq/kg when frying keropok lekors, compared to only 2.13 meq/kg for fresh oil. This trend was also evident in soybean oil, which had even higher peroxide values upon repeated use. When frying keropok lekors, both palm and soybean oils exhibited significantly greater peroxide values than when frying potato chips, likely due to the rich fatty acid composition of fish in the former that accelerates oxidative degradation. Thus, heating oil multiple times, especially using high-fat content foods, leads to a marked decline in oil quality, posing potential health risks to consumers.

Conclusion

The findings suggest that frying foods, particularly those rich in fish oils like keropok lekors, in repeatedly heated oils can substantially degrade oil quality. It is recommended that vegetable oils not be reused more than two times for frying to ensure safety and minimize health risks associated with the consumption of oxidized oils. The study highlights the importance of public awareness regarding the dangers of using repeatedly heated oils in food preparation, particularly in the Malaysian context where this practice is common.