By-Products from Sugar Industry
India is one of the important sugarcane (Saccharum officinarum) growing countries of the world. Five main by-products are available from the sugarcane industry namely: sugarcane tops, bagasse, molasses, press mud, and condensed molasses solubles.
Bagasse: Bagasse is one of the most important by-products of the sugar industry. About 5.26 million tonnes of dry matter from the bagasse is produced annually in India. Bagasse is used primarily as a fuel in the boilers of sugar industry. Small quantity of bagasse is also used for the pulp and paper manufacture. There are other uses of bagasse also, like the production of furfural, which has not yet been taken up on a commercial scale in India.
It is a good source of cellulose but is poor in protein (1.3 %) and high in lignin (16%). At IVRI, Izatnagar it has been used successfully as a roughage for ruminants. Extensive studies have been done by the BAIF where it has been shown that high temperature and high pressure treatment improves the palatability and digestibility of bagasse. This organization has also developed a technology for the production of complete economical feed using treated bagasse.
Molasses: It contains about 50 % sugar. The production of molasses is dependent on the production of cane sugar. It is about one-third of the quantity of sugar and about 3 % of sugarcane. Almost about 70 % of the total molasses is being utilized by the distilleries for the production of alcohol. Molasses has been used for many years as a cheap source of energy in the rations of farm animals.The proximate composition of the molasses include water 20.6%, total sugar 60.8%,crude protein 3.2%, soluble gums 2.2%, ash 8.2% and combined and free acids 5.0 %. Molasses has been mainly used in animal feeding at 5 to 10 % level. At IVRI, Izatnagar, molasses has been used as a main source of energy along with urea which was given as a main source of nitrogen in the form of urea-molasses-liquid feed.
Molasses has also been used as a binding agent with urea. At Ludhiana, ‘Uromol’compound was prepared by heating urea and molasses in the ratio of 1 : 9 (w/w) at 110°C. The studies have shown that in “Uromol” feeding higher leve ls of urea nitrogen can be incorporated in growing and lactating buffaloes. At NDRI, Karnal molasses bound urea has also been used as a protein replacer for the la c ta t ing a nima ls . T he Ur e a - mo la sse s-min e r a l b lo c ks (UM M B ) we r e a lso prepared both by hot process as well as cold process with NDDB taking a lead in its development and commercialization. The UMMB have been used as nutrient supplement for energy and minerals in India as well as in many other developing countries of Asia.
Condensed Molasses Solubles/Dried Yeast Sludge: It is a by-product of various fermentation processes in which large quantity of molasses is used to produce alcohol, yeast, citric acid, monosodium glutamate, etc. This product is a rich source of microbial protein and is a useful ingredient of animal feeds. After condensation to 65 to 75 % dry matter, it is called the condensed molasses solubles. In India the product available after fermentation of molasses to alcohol is called the ‘Yeast sludge’. Dried yeast sludge has been safely incorporated as an ingredient to a basal cereal free ration in the poultry at 20 % with better results.
Press mud: It is obtained as a by-product of sugar industry during the precipitation process of impurities. The yield ranges from 3 % in the sulphitation process to 7 % in the carbonation type of processing. The organic matter content of the press mud is as high as 64% and is considered as a rich source of calcium. The potential feeding value of press mud has not been fully exploited even though there are reports of using this by-product in the ruminant rations in combination with traditional feed resources at lower levels without any adverse effects.