Compositional and Nutritional Properties of Ghee Residue

Ghee-residue is the by-product of ghee manufacturing industry. It is partially charred light to dark brown colour and moist residue that is obtained on the cloth strainer after the ghee is filtered. During the manufacture of ghee, the solids not fat (SNF) present in cream or butter appears in the smaller particles, that are known as ghee-residue. It is obtained after molten ghee has been either strained out with either bag filters or muslin cloth or separated by continuous centrifugal clarifiers. Ghee residue is a rich source of fat and protein. It also contains considerable amounts of minerals. Ghee residue is used as a human dietary supplement. The nutritional value of ghee-residue, protein is low due to the damage of some essential amino acids (EAA) during preparation of ghee at high temperature. The lack of lysine in ghee-residue is the most dominant factor in depressing the protein efficiency ratio (PER) of ghee-residue. The supplementation of ghee-residue with a combination of some essential amino acid like lysine (8%), methionine (2.5%) and tryptophane (1.4%) increases its nutritional value as slightly higher than of skim milk powder (SMP). It has been observed that skim milk powder (SMP), a combination of SMP: ghee residue (2:1), SMP: ghee-residue (1:2) and ghee-residue diets have protein efficiency ratio (PER) of 3.44, 3.07, 2.46 and 0.66 respectively. Ghee residue contains many micronutrients like tocopherols, phospholipids, and by-products of browning processes, it possesses excellent antioxidant activity. The antioxidant effects of fat-insoluble molecules in ghee residue were observed to be better as compared to those of its fat-soluble ones (Selvamani et al., 2017). The yield of ghee - residue varies with the different methods of preparation of ghee. This is due to the variation in the non-fatty serum constituents of the different raw materials used for the preparation of ghee. The average yield of ghee-residue is higher is found in direct creamery (DC) method (12%) followed by yield in creamery butter (CB) method about 3.7% and desi butter (DB) method. Ghee-residue, particularly one obtained from creamery-butter, has higher content of phospholipids (17.39%) of its total fat (Khanam and Prasuna, 2017). Higher phospholipids (lipids) content of ghee-residue is beneficial in developing certain products where emulsification of fat and aqueous phase is desired. Keeping quality of all types of ghee residue clarified at 120°C is 3 months. Ghee residue can be utilized in the food industry to enhance milk products, bakery products and confectionary products as well as in animal feed and biofuel production.