Studies on the Utilization of Pawpaw Seeds as a Source of Seed Oil

Abstract

The seeds of Pawpaw (Asimina triloba) used for this study were collected from harvesting areas in Japan (Hiyogo, Tottori and Tokyo) late September to mid. October. General components of the seeds (moisture, crude fat, crude protein, crude fiber, ash and nitrogen free extract), saccharides (starch, sucrose and reducing sugar) and amino acid composition of defatted Pawpaw seed meal were determined. After the seeds were heated at 100 degrees C for 15 min in steam, the seed coats were removed and the decoated seeds were ground carefully by hand grinder. The ground meal was then extracted with n-hexane to obtain crude oil. The physical and chemical properties of the crude oil and refined oil obtained by standard refining treatments (alkali refining, bleaching and deodorizing) were studied. Also the acute toxicities of crude oil and refined oil with Wister-strain male rats were tested by intraperitional injection. Moreover, the feeding tests of the seed oil and defatted seed meal using Wister-strain male rats were carried out. The results were following: 1) The seeds of Pawpaw contained 33. 5% of fatty oil which consisted of the glyserides of C16:0, C16:1, C18:0, C18:1, C18:2 and C18:3. The seed oil was very available as edible oil in view of physical and chemical properties including of the fatty acid content. 2) When the crude oil or defatted seed meal was included in the control diets, the acute toxidty was observed in the rats fed with those diets, although the toxicity of the crude oil was detoxified with refining treatments. The defatted seed meal, however, could not be detoxified when it was heated at 120°C for 30 min in autclave. 3) The seeds of Pawpaw contained 12. 096 protein having a good nutritive value considering the number and amounts of essential amino acids which it furnished. These results suggest that the refined seed oil of Pawpaw is a good edible oil and its defatted seed meal is available as feed-stuff if it is able to detoxify.