The present invention has a simple equipment and low energy consumption, to be prevented at low cost and efficiently oxidation of edible oil. The present invention relates to a power supply with an AC power source grounded one output terminal, and a rectifying element having one end in series with the ungrounded output terminal of the AC power supply to prevent the outflow of current from the ungrounded output terminal is connected Using the device, the it is possible to connect a conductor made of the electrode plate to the ungrounded output terminal, an outer surface of either or metal containers the conductor made of the electrode plate is immersed directly into the food in a metal container of the power supply It can be placed in, by generating an electric field variation by application of the AC power to the conductor made of the electrode plate by applying a negative potential variation, to reduce the oxidation prevention of the edible oil in the metal container.本発明は、簡単な装置と少ない消費エネルギーでもって、安価に効率よく食用油の酸化を防止できるようにする。 本発明は、一方の出力端子を接地した交流電源と、当該交流電源の非接地出力端子に直列に一端が接続されて非接地出力端子からの電流の流出を阻止する整流素子とを備えた電源装置を用い、当該電源装置の前記非接地出力端子に導電体製電極板を接続すると共に、当該導電体製電極板を金属製容器内の食用内に直接浸漬するか又は金属製容器の外側面に配置して、前記交流電源の印加によって前記導電体製電極板にマイナスの電位変動を与えて電場変動を発生させることにより、金属製容器内の食用油の酸化防止を図る。
