Comparison of chemical composition of two durum wheat (Triticum durum L.) and bread wheat (Triticum aestivum L.) germ oils

Abstract

Wheat belong to the genus Triticum, as annual plants of the family Gramineae or Poaceae, grown in many countries, including Tunisia with one million hectares annually. Wheat grain is a particular fruit, caryopsis and the outer envelope is adherent to plant seed material. During milling, envelopes (hulls) are separated from the grain (endosperm + embryo). The embryo or germ is the essential part of the seed to plant reproduction and is containing a lot of fat (about 15%) or oils. The Soxhlet technique is used for the extraction of wheat germ oil. Normal hexane (n-hexane) is commonly used for edible oil extraction. Comparison of the extracted oil of durum wheat germ and soft wheat germ showed a marked difference in their chemical composition. The basic chemical composition analyses revealed low values of dry matter (14.77g /100g of durum wheat germ and 19.87g /100g of Soft wheat germ), low amounts of total ash content (5.3g/100g of durum wheat germ and 4.99g /100g of Soft wheat germ) and high fat contents (17.12g /100g of durum wheat germ and 15.96g /100g of Soft wheat germ). The yield of extraction by Soxhlet was about 13.12% for durum wheat germ and 11.22% for soft wheat germ. The fatty acid composition of these two wheat germ oils indicates the presence of C18:2, C16:0 and C18:1. The major one is C18:2 with 56.68% for Soft wheat germ oil and 53.43% for durum wheat germ oil