Many uses of cottonseed.
According to the study, domestic edible oil consumption is increasing at an annual rate of 7.7 per cent against production rate of 2.6 per cent annually over the last 24 years. The gap between production and consumption rate is being bridged by spending a huge amount on the import of edible oils each year. The study points out that cotton is primarily grown for its fibre and oil is a by-product. Its seed contains 18-24 per cent oil. It contributes about 68 per cent to the domestic vegetables oil production. The potential for increasing cottonseed productivity is still fairly large.
The study observes that even an increase of 2 to 3 per cent in the quantity of quality seed of a commercial variety, could save millions of rupees being spent on the import of edible oils. The constraints responsible for low promotion of oil seed crops in the country have been poor marketing system, lack of farmers' economic viability and inadequate support of essential production inputs like credit, quality seed, production technology and appropriate farm machinery.
At present, the potential of cotton as an oil seed crop is not being properly realized in the country. Post-harvest losses of seed are considerably high. These include losses in transportation to ginneries, storage after delinting and before going to expellers. These need to be streamlined in such a way that losses are minimised. The experts say that most of the cottonseeds in Pakistan are being extracted by using indigenous type of oil expellers which are inefficient devices and the cake so produced still retains 8 to 9 per cent oil. This oil cake is fed to the cattle which is more than their requirement and, therefore, goes waste through their faeces. These outmoded machines can be replaced by solvent extraction system. According to an estimate about 2.2 million tons of cotton cakes are produced in the country, which can yield 154 thousand tons of oil (worth Rs. 4.6 billion) if all of it is processed through solvent system.
According to the study, cottonseed is a rich source not only of oil but also protein. Its oil contains fatty acids like myristic, palmitic, palmitoleic, stearic, oleic and linoleic acids. About 17 different kind of amino acids including essential amino acids like isoleucine, leucine, threonine, methionine, phenylalanine, lysine, histidina and arginine have been isolated from cottonseed meal. Cotton seed oil has good flavour stability which makes it ideally suitable for frying. Its iodine number (100 to 116) is lower than that of soyabean or sunflower oil, hence cottonseed oil has a longer shelf life.
The study further points out that cottonseed cake produced through decortication and mechanical extraction of its oil, contains about 36 per cent crude protein which is best protein supplement for livestock. Its protein can be utilized in low cost food grain products that can provide functional and nutritional properties in food formulation. These derivatives can supplement protein-deficient diet in areas of the world suffering from food shortage.
Four dairy products: processed cheese, fresh cheese, ice cream and sour milk were improved by the utilization of cottonseed flour. Results indicated the possibility of substituting 10-15 per cent of milk non-fat solids by cotton flour to produce low price acceptable ice cream. The study makes claim of successfully preparing milk by adding 15 per cent cotton flour to cow milk without any adverse effect on the product. Both processed and fresh cheese were prepared by partial substitution of milk solids by cotton flour.
According to the study, "a popular type of snack food known as coconut was prepared by roasting or frying glandless cottonseed kernels. Processed nuts can be stored in polythene bags for 4-6 weeks without organoleptic changes. Laboratory animals were used to evaluate growth effect of feed containing cottonseed. Results indicated that glandless cottonseed protein promoted growth rate. A feeding efficiency comparable with casein was found. Average gain in weight was 52 grams for casein compared with 48 gins for cotton protein. Higher lysine content was found in cotton flour which had 4.7 - 5.2 gram lysine compared to 1.92 gram in wheat flour.
According to these experts, cotton seed flour was successfully used in the preparation of three baby formulas, vegetables soup and filler in the sausage. The three baby formulas were prepared with 25 per cent. The amino acid patterns of the formulas were slightly lower than that of human milk. Cotton flour soup was less acceptable than lentil soup but the protein was 80 per cent higher than lentil soup. Sausage prepared by replacing 10 per cent of wheat with cotton flour was acceptable to judges. "In-vitro digestibility tests of cotton flour indicated that it was more easily digested than wheat flour. The digestibility value of cotton flour by pepsin-pancreatic was 90.7 per cent compared with 73.7 per cent for wheat flour and 100.6 per cent for casein. Baby food digestibility was more than 80 per cent".
The study points out that quality of cotton seed products is impaired by the presence of a terpenoid compound gossypol, which causes discolouration in cotton seed oil and in egg yolks when cotton seed meal is fed to poultry, reduces availability of lysine in cotton seed protein, and causes toxicity if cotton seed meal is fed in excess to poultry. A glandless character controlled by two recessive genes (GL 2 and GL 3) were introduced into commercial varieties to improve seed quality, but insects have preference for gossypol free variety. The cotton breeders are now looking for other variations of glandlessness, such as varieties having gossypol gland in the leaves and stem but not in the seed.
The nutritional value of the biscuit was also improved by adding 15 per cent of cotton seed flour to wheat flour. Protein content increased from 8.22 to 19.2 per cent. Fine cotton flour was considered better than coarse. Macaroni was the third food product improved by the addition of cottonseed flour. The addition of 5 per cent of the cotton seed flour to semolina produced comparable product with pure semolina but improved protein, fat and mineral content.
The study goes on to say: "it is high time for cotton breeders of the country to design a comprehensive programme for tailoring cotton varieties possessing harmonious combination of fibre with oil and protein yield. Such a programme can be linked up with all those ventures already being undertaken by the government to boost up edible oil production in the country". The experts claim that by looking at the problem in its proper perspective, the Department of Plant Breeding and Genetics, University of Agriculture, Faisalabad has initiated a breeding programme for the development of high oil content varieties without affecting the fibre yield quality. In this connection a study was carried out to understand inheritance pattern of seed oil content and fibre yield along with fibre quality trait like length, strength and fineness.
Genetic variation observed for these traits was found to be highly heritable, thus suggesting that improvement in the quality traits could be accomplished through simple selection producers. Heterosis (increase in performance of hybrid over parents) was observed for oil content, fibre length and strength. The extent of relationship between these quality traits was also ascertained which indicated that possibility existed for the simultaneous improvement of these traits.