Check the purity of milk for dairy milk collection centre duration. The fat thus collected is called cream and the milk deprived of fat is called skimmed milk or skim milk. Relationship among milk density, composition, and temperature a thesis presented to the faculty of graduate studies of. The principle involved in measuring the specific gravity by a lactometer is that a floating object sinks until it has displaced a weight of fluid equal to its own weight. There are many different hydrometer designs with varying ranges and calibration units. The specific gravity of water is usually expressed at 4c. Effect of severity of mastitis on ph and specific gravity of buffalo milk table 1. Mean milk specific gravity concentration of normal and mastitic buffaloes. The specific gravity of milk does not give a conclusive indication of its composition since milk contains a variety of substances that are either heavier or lighter than. The greater is the volume of the displaced fluid, the smaller is the specific gravity of the fluid, and the lower is the lactometer reading. Specific gravity, ratio of the density of a substance to that of a standard substance. Lactometer is a special hydrometer designed for use with milk graduated in the range of 1. Twelve matured lactating ewes weighing between 16 and 24 kg live weight were used to evaluate the effects of stage of lactation and parity on milk composition and specific gravity of milk of west.
In most of the cases the reference substance is water for liquids or air for gases. Since the mass of a given volume of water at a given temperature is known, the volume of a given mass, or the mass of a given volume of milk, cream, skim milk etc can be calculated from its specific gravity. The chemistry of coconut milk and cream coconut handbook. Density specific gravity an overview sciencedirect. As the beverage ferments, the sugars are converted into carbon dioxide and alcohol which is lighter than water so the specific gravity number decreases. Specific gravity is the ratio of the density mass of a unit volume of a substance to the density mass of the same unit volume of a reference substance. Additional tests for fat content are necessary to determine overall composition. The result is said to be their specific gravity often abbreviated to sg. Since 1 ml of water at 4c weighs 1 g, the mass of any material expressed in gml and its specific gravity both at 4c.
Milk testing and quality control food and agriculture. The condensing of skimmed milk revealed the significantly p specific gravity 1. Twelve matured lactating ewes weighing between 16 and 24 kg live weight were used to evaluate the effects of stage of lactation and parity on milk composition and specific gravity of milk of west african dwarf wad sheep in a semiintensive system of management. The quality attributes are affected by many factors, such as the variety of nuts, water quality and volume used for coconut milk extraction. Pdf twelve matured lactating ewes weighing between 16 and 24 kg live weight were used to evaluate the effects of stage of lactation and parity on milk. The specific gravity of the whole cows milk ranges from 1.
The specific gravity of normal milk usually ranges between 1029 and 1034, and will average about 10315. Specific gravity is an expression of density in relation to the density of a standard or reference usually water. The most convenient and accurate method to determine the specific gravity of milk is lactometer measured at 15 o c or 20 normally 1. The displaced fluid has equal weight as the floating body. On the average the specific gravity of milk at 15 c15 c is 1. Hydrometers work according to the archimedes principle. Specific gravity of milk it is the ratio weights equal volumes and distilled water at same temperature. Yoghurt milk and other dairy mixes containing sugar and added milk solids exhibit higher density and specific gravity than milk. Milk testing and quality control is an essential component of any milk processing industry whether small, medium or large scale. Determination of specific gravity of milk posted on. Pycnometer method the files are in electronic format pdf docdocx and will be sent to your email within 24 hours. As you add sugar, malt extract, honey, or other soluble solids, the numbers after the decimal point increase. Pdf composition and specific gravity of milk of wad. Specific gravity of milk, which is the ratio of density of milk to that of water at that temperature, is reported at 15.
Lactometers are used for rapid determination of specific gravity. This lab is performed to determine the specific gravity of soil by using a pycnometer. Lactometer works on the principle of fluid displacement. Determination of milk specific gravity specific gravity is the relation between the mass of a given volume of any substance and that of an equal volume of water at the same temperature. The importance of specific gravity dynamix agitators. Beverages, almond milk, sweetened, vanilla flavor, readytodrink weighs 253. The specific gravity of milk measured at 15oc or 20oc is normally 1. Gases are commonly compared with dry air, which has a. Density measurement of milk and dairy products the engineer. Specific gravity is the ratio between the weight of a certain volume of milk at a standard temperature of 15c and the weight of the same volume of water at the same temperature. Ranges in the specific gravity of milk fat rneasured at the stated. The solids of milk consist of fat, casein, albumen, sugar and ash. Specific gravity chart fluid temperature deg c specific gravity heptane 25 0. Then, fat can be collected or skimmed from the milk.
Experiment 4 specific gravity determination purpose. Hydrometer usage and specific gravity tables hydrometry hydrometry hydro water, metrymeter measure use the principles of buoyancy or flotation to measure liquid densities. The lactometer test is designed to detect the change in density of such adulterated milk. The density and specific gravity of milk is usually given at 15. It is a milky fluid obtained by manually or mechanically extracting fresh kernel. Determination of specific gravity of milk by lactometer fig. Density of immunoglobulins that pass from the dairy cow to the calf in the first milk colostrum is im portant in the calfs development of high levels of passive.
Journal of chemical and pharmaceutical research, 2015, 72. Pdf composition and specific gravity of milk of west. The specific gravity of skimmed milk is greater than that of whole milk because because cream is lighter than milk, thus removing it makes the remaining liquid heavier per unit of volume. The difference in weights is divided by the weight of an equal volume of water to give the specific gravity of the liquid. Determine the snf in milk by specific gravity method. Milk being made up of 87% water is prone to adulteration by unscrupulous middlemen and unfaithful farm workers. Pdf composition and specific gravity of milk of wad sheep as. Density of milk, chocolate, fluid, commercial, reduced fat. Average specific gravity of whole milk was observed as 1. Since fat has a specific gravity of 09, which is considerably less than the specific gravity of milk, removing part of the fat from milk by means of skimming will cause the partially skimmed milk to have a higher specific gravity or higher lactometer reading than the whole milk. The specific gravity of some major milk constituents are. A better test of firstmilk quality california agriculture. A hydrometer is an instrument that measures the specific gravity of a liquid. The specific gravity of cream decreases regularly with increase in the fat content.
The specific gravity depends on the protein and fat content. The specific gravity was obtained by dividing the weight of milk displaced by the bulb, by the weight of airfree, distilled water dis placed by the bulb, both. Since fat has a lower specific gravity and therefore is lighter than the milk serum, fat globules rise to the milk surface. Specific gravity is commonly used in industry as a simple means of obtaining information about the concentration of solutions of various materials, or of quality control for polymer materials. Specific gravity of common liquids and fluids like alcohol, oils, benzene, water and many more sponsored links specific gravity of a liquid is the ratio of the density of the liquid to the density of water at 4 o c. Usually, our reference liquid is water, which has a density of 1 gml or 1 gcm3. It was believed that more precise measurements than have. Milk is a very complex liquid that is composed of an expansive diversity of different molecular species. Specific gravity is the ratio of the mass of unit volume of soil at a stated temperature to the mass of the same volume of gasfree. Beverages, almond milk, sweetened, vanilla flavor, ready.
The removal of water in the manufacture of concentrated milk products raises the specific gravity. Specific gravity is the relation between the mass of a given volume of any substance and that of an equal volume of water at the same. The nutritional composition of dairy products milk whole milk 5 semiskimmed milk 6 skimmed milk 7 channel island milk 8 breakfast milk 9 condensed milk whole and skimmed 10 dried skimmed milk fortified 11 evaporated whole milk 12 evaporated milk 4% fat flavoured milk 14 milkshake thick, takeaway type 15 yogurt and fromage frais. The specific gravity of milk does not give a conclusive indication of its composition since milk contains a variety of substances that are either heavier or lighter than water. Both density and specific gravity describe mass and may be used to compare different substances. Hydrometer basics for home brewing and wine making. Density specific gravity specific gravity is defined by astm d4439 from volume 04. This study shows that specific gravity of the first milk is a better gauge of immunoglobulin density than conventional observation. Density of immunoglobulins that pass from the dairy cow to the calf in the first milk colostrum is important in the calfs development of high levels of passive immunity. The specific gravity of an object is the ratio between the density of an object to a reference liquid. The influence of the physical state of the fat on the calculation of. Being the product of mammary glands, milk is the primary food source for neonatal mammals. When its adultered with water or other materials are added or both misdeeds are committed, the density of milk change from its normal value to abnormal.
Milk, chocolate, fluid, commercial, reduced fat, with added calcium weighs 264. Full text of determination of the specific gravity of. Most of the specific gravity determinations were made with a hydrometer at temperatures below 20 c. It is the result of the specific gravities of each of its components. In this experiment, we will investigate the specific gravity of liquids via construction of a hydrometer. What is the specific gravity of whole milk answers. Groups rirht left overall mean front rear front rear control 1. Apparatus lactometer this is a hydrometer a device for measuring specific gravity adapted to the normal range of the specific gravity of milk. The bottle is weighed, filled with the liquid whose specific gravity is to be found, and weighed again.