Molasses and beet pulp are by-products of the sugar industry. Every tonne of processed cane or beet will lead to the production of molasses, the by-product from which no additional sugar can be obtained by further crystallisation. Molasses still contains a substantial amount of sugar. It is also characterised by the richness in chemical elements which can be exploited for a variety of purposes. Beet pulp remaining after the extraction of sugar from beet is a good source of highly digestible fibre and energy, used for animal feeding. Molasses and beet pulp are mostly used domestically but about 7% of world output of molasses and 15% of global beet pulp production are exported to the world market.
From a technological point of view, molasses is the runoff syrup from the final stage of crystallisation, from which no additional sugar can be obtained by further crystallisation. The syrup after the first crystallisation is normally referred as A molasses. If the process of evaporation and centrifuging is repeated in order to recover more sugar, the resulting syrup residues are then referred as B molasses. In general, 100 tonnes of sugar cane will yield 10-11tonnes of sugar and 3-4 tonnes of molasses. Meanwhile 100 tonnes of sugar beet will give 11-12 tonnes of sugar and 4-6 tonnes of molasses.
Molasses consists of water, sugar, glucose and fructose (i.e. reducing sugars or fermentable carbohydrates), non-sugar substances from cane and beet not precipitated during juice purification, and substances formed enzymatically or chemically during the storage and handling stages. Because molasses is an agricultural product, it is hard to establish its exact composition. Climatic factors, soil structure, and processing conditions in the cane mill or the beet factory all influence the final quality. Molasses contains substances which may promote but, in some cases, also inhibit the growth of microorganisms.
The pulp that remains after sugar is extracted from beet has long been recognized as a valuable animal feed. Wet pulp typically contains from 6% to 12% of dry substance. Pressed pulp can be dried alone or combined with molasses or vinasse. The proportion of dry substance is thus raised to 87–92%. Nutritionally, beet pulp pellets mixed with an amount of molasses have the roughage properties of chopped hay and the high energy characteristics of corn. This feature makes molasses beet pulp pellets a valuable feed for cattle feeders, dairies, and lamb feeding operations.