RESUMEN
The chemical properties and nutritive value of five of tissue fat, the retro-peritoneal fat (Ⅰ), bone marrow fat (Ⅱ), bone marrow fat+worm wax (pai la) (400:1) (Ⅲ), scrapped fat from the inner surface of the skin (Ⅳ) and the omentum fat (Ⅴ), have been investigated. Fat Ⅰ, the ordinary lard habitually used in Chengtu is used as a control.The melting point of Ⅰ(35.4℃), Ⅲ (37.4℃) and Ⅴ (38.4℃) are higher than those of Ⅱ (25.7℃) and Ⅳ (25.7℃). The addition of a small quantity of worm wax into the bone marrow fat can obviously raise the melting point of the latter, and thus improving its organolyptic properties.The saponification values of the five kinds of fats are about the same, and there is significant difference in their iodine values. The degree of unsatura-tion of fat Ⅱ, Ⅲ and Ⅴ are higher than those of Ⅰ and Ⅳ.The ash contents of the fat Ⅳ and Ⅴand the acid value of the fat Ⅰ are somewhat lower.Feeding experiments with albino rats show that there is no difference in the digestibilities and the growth promoting effects of the five kinds of fats incorporating with the soy bean basal diet.It is concluded that the use of the by-products from the butcheries for the preparation of the edible fat are not only entirely permissible but also economically beneficial.The addition of worm wax into the bone marrow fat for the improvement of the organolyptic properties (color, consistency) is a economical waste.