Page 1 : { }, 1 38 J, , Market Milk, , , , 35.3 Reconstituted Milk, , Reconstituted milk may be prepared either from skim milk powder (SMP) or whole milk powder, by the addition of water. The composition especially fat:solids not fat ratio is adjusted equal to, , that of fresh skim milk or fresh whole milk. Whole milk powder possesses problems in, reconstitution because of poor wettability. Therefore, reconstitution should be done with care. The, temperature of water should be between 40-45°C. After reconstitution, it should be held for, sufficient time, preferably for one hour, for proper hydration of powder particles, For greater, convenience, instant powder in which wettablity is increased by agglomeration, may be used., When skim milk powder is to be used after reconstitution for extending the fluid milk supply, eg., in preparing recombined or toned milk, low heat SMP should be the choice. Reconstitution, equipments involve the use of high speed agitators creating a vortex or a ventury type mixer and, pump to speed up dispersion and solution of powder. Preparation of whole milk from whole milk, powder after reconstitution is not as common as reconstituted skim milk because of certain special, problems. Whole milk powder has poor wettability due to presence of fat, which is hygroscopic to, water. The shelf life of whole milk powder is also limited., , , , 35.3.1 Advantages, , 1. Ithelps in making up the shortage of fresh milk supplies in developing countries., 2. Itis useful for the armed forces posted at far-off places that are difficult to reach., , 35.3.2 Method of manufacture, , A calculated amount of potable water is received in the pasteurizing vat/ tank equipped with an, agitator. The water is heated to 38-43°C, while the agitator is kept in motion. A calculated amount, of skim milk powder (for reconstituted skim milk) or whole milk powder (for reconstituted whole, milk) is slowly added at the time of agitation and the mixture is thoroughly agitated till it, dissolves completely. Special powder mixture equipment may be used for this purpose. The, mixture is, pumped through a filter, homogenized (in case of reconstituted whole milk),, pasteurized at 63°C for 30 min and promptly cooled to 5°C or below until distribution (Fig. 35.3)., , Receiving water in pasteurizing vat ], , Pre-heating to 38-43°1, , Fe, , Addition of whole milk power and mixing |, , Filtration, , Pasteurization (63°C/30 min) or by, HIST method |, , Cooling (5°C), , Enea, , Packaging and storage (5°C), , , , , , , , Fig. 35.3 Manufacture of reconstituted milk, , , , Market Milk, , , , Reconstitution is usually done by:, , + Funnel or ventury system., * Tri-blender or dry material-liquid blender system., , 35.3.2.1 Funnel or ventury systems, , In this system, the water flows through a pipe to a jet which increases the velocity of the water, flow. At the time of outlet from the jet, the powder flows from the hopper which is connected with, the pipe into the high velocity stream of water. The jet acts as a ventury and creates alittle vacuum, to suck the powder from the hopper. The pipeline then returns to the holding tank so that the, liquid circulates in the system until all the powder has been satisfactorily dissolved. A high speed, centrifugal pump is used for re- circulation., , 35.3.2.2 Tri-blender or dry material-liquid blending system, In this system, thorough mixing of powder with water takes place in a centrifugal pump as the, , powder directly falls on to the pump impeller. This system is found to be most effective. The, reconstituted skim milk is immediately chilled and stored.

Page 2 : In this system, thorough mixing of powder with water takes place in a centrifugal pump as the, powder directly falls on to the pump impeller. This system is found to be most effective. The, reconstituted skim milk is immediately chilled and stored., , 35.4 Recombined Milk, , This refers to the product obtained when butter oil (also called anhydrous milk fat), skim milk, powder and water are combined in the correct proportions to yield fluid milk. Fat may also be, obtained from other sources, such as unsalted butter or plastic cream. The acceptability of, recombined milk is influenced by the quality of anhydrous milk fat. Recombined milk serves as a, mean of supplying fluid milk in non-dairy areas. The recombining process offers several, advantages. It reduces transport cost, eliminates refrigeration, and lowers packaging cost bes ides, helping in the development of local industries. The main market for recombined milk and milk, products is in developing countries, where they make up for the milk shortages and also find, increasing utilization in emerging situations., , 35.4.1 Legal Definition, , ‘Under the FSS Rules (2011), recombined milk shall contain a minimum of 3.0% fat and 8.5% SNF, throughout the country., , 35.4.2 Advantages, + Help in making up for the shortage of fresh milk supplies in developing countries, especially in, the lean seasons., , * Help to prevent the rise of the price of liquid milk in cities., , 35.4.3 Recombination process, , The process for preparing recombined milk is given in Fig. 35.4., , , , ‘ }, { tJ, , Market Milk, , , , Receiving water in pasteurising vat, Pre-heating (3 8-43°), ‘Addition of skim milk powder and mixing, 8-43"), , fe, , Addition of butter oil and mixing, (42-49°C), , , , , , , , Filtration |, Pasteurization (63°C/30 minutes), , v, , Homogenization (2500 psi/63°C), , ¥, , | Cooling °C) |, [ Packaging and storage (53°C) |, Fig. 35.4 Recombination process 7, 35.4.3.1 Mixing of butter fat, , The source of butterfat is usually butter-oil or unsalted white butter. The steps involved are:, , 1. Butter-oil tins are heated to above 50 to 55°C in a tank containing hot water with steam to, liquefy the butter-oil., , 2. The tins are opened or a few big holes are made on the lids., , 3. The liquefied butter-oil is emptied out in the butter vat thoroughly., , 4, Butter-oil is pumped to the butter-oil storage tank and heated to about 60 to 65°C., , The butter-oil is then injected into the milk stream at a speed set by a variable speed positive, pump immediately prior to the homogenizer, which is connected to the pasteurizer. The milkbutter-oil mixture is homogenized by a two-stage homogenizer at 140 and 35 kg/cm2. It is then, pasteurized and stored., , 35.4.3.2 Blending with reconstituted milk, , Pasteurized reconstituted skim milk in predetermined quantity enters the storage tank containing,, the previouslv processed milk batch (with butter-oil) and are blended. Final standardization is