Composition and Nutritive Value

i. Composition

Butter consists of milk fat, non-fat-constituents and water. The water is uniformly dispersed as fine droplets in butter so that it looks dry. Main constituent of butter is milk fat comprising glycerol and fatty acids. Milk fat is comprised mostly of triglycerides, with small amounts of mono and diglycerides, phospholipids, glycolipids and lipoproteins. The triglycerides (98% of milk fat) are of diverse composition with respect to their component fatty acids, approximately 40% of which are unsaturated.

Butter melts at about 35°C (96 °F) and re-solidifies at 23°C (73°F). The firmness of butterfat varies with the proportion of saturated and unsaturated fatty acids,chain length, degree of un-saturation (mono or poly), and position of the fatty acids on the glycerol molecule. The change in butter softness is associated with the changes in fatty acid and triglyceride structure of the milk fat. On an average,butter contains about 50.5% saturated fatty acids, 23.5% mono-unsaturated fatty acids, 3.0% poly-unsaturated fatty acids and 0.22% cholesterol. A typical fatty acids composition of butter is depicted in Fig.

Fatty acids play an important role in development of butter flavor. These are present various concentrations. Although long-chain fatty acids are present at higher concentrations in butter, they do not make a significant contribution to its flavor.Short-chain fatty acids (SCFA), on the other hand, do play an important role in the flavour of butter. Typically, SCFA’s are found in the serum portion of butter (aqueous solution of all non-fat components) where their flavor potential is stronger. Butter flavour can be enhanced and sharpened by emulsifying fats with skimmed milk that has been cultured with lactic acid bacteria. The flavour of butter can also be simulated by the addition of butanedione.

Fatty acid composition of butter

Non-fat constituents of butter include protein, calcium and phosphorus, sometimes referred to as curd residue and are present as minor constituents of butter. Butter also contains fat-soluble vitamins like A, D, E and K. Chemical composition of butter depends upon on the method of manufacture. . On an average butter contains 80% fat, 16% moisture and 2% non fat milk solids . The titratable acidity of butter should be below 0.2% L.A.

 

ii. Nutritive Value

Butter is a water-in-oil emulsion, with 80% milk fat, 16% moisture, and 2% milk solids-not-fat either with or without salt. Butter has very high-energy value. Butter containing 80 per cent fat provides 7.2 cal/g. Milk fat provides some essential fatty acids and also serves as a carrier of fat-soluble vitamins like A, D, E and K and promotes their absorption. It contains significant amounts of vitamin A (30 I U /g), which is important for eye-sight, to maintain healthy skin and resistance to infection. Vitamin D is also found in butter, which is required for bone strength and calcium absorption aids to provide good bone strength and calcium absorption.Conjugated linoleic acid present in milk fat assists in preventing certain types cancer, in particular breast cancer, helps to keep the heart healthy and enhances the immune function in the body. Fresh butter being in emulsified form is easily digestible than melted form. Vitamins and mineral contents of butter are given in Table

Vitamin and Mineral content (mg/100 g of butter)

Butter is generally considered to be safe from pathogens as the moisture content is low and uniformly distributed in the whole mass as numerous microscopic droplets that is relatively high in sodium chloride concentration. The fat portion of butter is also safe from microbial degradation.