Studies on the Preventive Method of Lipid Oxidation in Freeze-dried Foods

Part III. Antioxidative effects of spices and vegetables

Abstract

Several essential oils, components of these oils, and three vegetables (welsh onion, chinese garlic and ginger) were tested for their antioxidative effects on both dehydrated model based on carboxymethylcellulose and dehydrated pork. Samples treated with each materials mentioned above by various means were packed in cans under an atmospheric pressure after freeze-dehydration. The cans were stored at 37°C and the rancidity of the contents was measured at intervals by thiobarbituric acid and peroxide value test or by the oxygen analysis of the head space. Both clove and thyme oil exhibited apparent antioxidative effects and similar results were obtained with eugenol and thymol, the major components in respective oils. When the model system or pork was dehydrated with welsh onion or garlic which was placed separately on the same shelf of the dryer during dehydration, the process of oxidation was retarded even in the absence of welsh onion or garlic themselves in the cans. However, much higher effects were obtained in cans packed with dehydrated welsh onion or garlic, and the addition of allyl sulfide or allyl disulfide prior to the dehydration revealed the highest antioxidative effects. With ginger, the effect was lower than with welsh onion or garlic, but the addition of the components of ginger, shogaol and zingeron, proved to have an excellent antioxidative effect comparable to that of allyl sulfide or allyl disulfide.