Can vegetable oils high in α-linolenic acid content be used for stir-fry cooking?

Abstract

Insufficient intake of n-3 polyunsaturated fatty acids (n-3 PUFAs) has invited health issues, such as cardiovascular and inflammatory diseases, in recent years. n-3 PUFAs include EPA and DHA, found in fish oils, and α-linolenic acid, found in plant oils. A reduced intake of fish has been reported among the Japanese people. Additionally, in many Western countries, fish is not regularly consumed. Therefore, vegetable oils high in α-linolenic acid can be consumed in order to increase the intake of n-3 PUFAs. The most common methods of intake are consumption of the oils raw, such as in dressings, or through their use in cooking, such as in stir-fries. Owing to its low oxidation stability, α-linolenic acid is unsuitable for heating. However, linseed oil has been reported to be safe for stir-fry cooking, if performed for a maximum of a 3 min heating period. Therefore, there is a possibility that other vegetable oils containing high α-linolenic acid can also be used for stir-fry cooking. At present, there are limited reports available on the effects of the differences in such oils or in stir-fry ingredients on oil degradation. This study measured the degree of oil degradation, using peroxide value, when vegetables (bean sprouts, carrot, and green pepper) were stir-fried using vegetable oils high in α-linolenic acid (flaxseed oil, perilla oil, and sacha inchi oil) and examined the appropriate combination of oils and ingredients. The results indicate that the oils can be safely used for stir-frying at 190 °C for 3 min. Furthermore, the use of carrots, accounting for 25% or more of the total ingredients to be stir-fried, significantly suppressed the lipid oxidation. It is, thus, expected that the use of vegetable oils high in α-linolenic acid for stir-frying can improve n-3 PUFAs deficiency.