Milk Powder Drying | Spray Drier

Milk powder made from fresh milk which reduced water content. Fresh milk has a water content of about 87 percent. While milk powder has a water content of no more than 2.5 percent. In the industrial manufacture of milk powder, used dryers usually spray drier type.

Spray Drier
Solutions and Suspensions which can be sprayed may be pumped into a stream of the drying medium. The large specific surface area of the small particles allows the solvent to evaporate quickly, leaving a dry product in the form of a powder. The essential components of a spray drier are the means of fluid dispersion, contact of spray and drying medium, and recovery of the dried product. The direct water heater is replaced by an indirect steam heater if the product must be free of contamination. Water filters may also be used. In some cases the dried product and exhaust air are both removed from the bottom of the drying chamber, and the product is separated in a separate cyclone.
The fluid may be dispersed or sprayed by pressure nozzles or by centrifugal disk bowl or nozzles.

MILK POWDERED|DAIRY PRODUCTS LABORATORY

Laboratory Quality Assurance

Quality Assurance (QA) is related to the department the entire production process from raw material, receiving fresh milk to finished product, Quality assurance task of researching micro dairy products. Before entering into the manufacturing process, fresh milk that comes must be checked whether the standard meets or not. If fresh milk is already meet the standard, then the fresh milk is already declared eligible and can be processed.

Tests done by the Quality assurance involves three things namely chemistry, physics and microbiology. Chemical examination levels include protein, fat ash, water, pH, sediment, total fat, Chlor test, metal testing, solubility, and others. Physical examination including examination of organoleptic and packaging. Microbiological examination covering the content of microorganisms such as Salmonella bacteria, Staphylococcus, and others. The parameter is the number of methylene examinations Blue Reduction Time (MBRT), which measures the level of bacteria in fresh milk. Examinations conducted by the Quality assurance include:

1. Before the examination process
a. Fresh milk inspection
Examination of fresh milk from cooperatives include micro organic test, physical test and bacteriological tests. Fresh milk that meets the specifications will be cooled for further processing.
b. Raw Material Inspection other than fresh milk
Raw materials used in processes such as WPC (Whey Protein Concentrate), Junior (Scheme Milk Powder), BMP (Butter Milk Powder), lactose, sucrose, maltose, palm oil, soybean oil, minerals, vitamins and pre-mix. Tests done on materials to be used in the production process, including checks micro organic test, physical test and bacteriological tests as well as the inspection of fresh milk.
c. Examination packaging materials
Packaging materials used include aluminum foil, folding box, carton box, and plastic spoons. Examination includes examining color, fold thickness, typography, paper strength, heavy layers of paper and glue. For a plastic spoon, the examination includes color and volume of a spoon.
2. In Process Inspection
Tests done during the production process going. Examination in process was also conducted by the Quality Control (QC). Guidelines and whether or not eligible to rely mostly results from the QC, because the results obtained more quickly. As for specific cases, the results of microbiological examination of QA is needed.
3. In Finished Product Inspection
Tests done by the Quality assurance on the same finished product tests done on the QC, but the status of eligible and whether or not still determined by the Quality assurance. At Quality assurance declared eligible, then the product is safe and can be distributed to consumers. If the product has taken two deviations will rework options whenever possible and discarded if it is not possible.

B. Laboratory Quality Control
Quality Control (QC) is a department in charge of quality control or monitor the macroscopic products. Tests done in the Quality Control is the physical and chemical examination, no microbiological examination. This is done before the product declared marketable. For accuracy monitoring, inspection of products made from the stage in process to finished product.
All materials used are the result of the Quality Control laboratory. Existing equipment is sufficient and carried out by experts in their fields. Inspection done intentionally to prevent the gradual deviations and can be followed up with appropriate treatment. Stages of examination conducted by the Quality Control include:
1. In Process Inspection
An examination of the product during the process of compounding the tank until the dryer. In the examination process conducted by the Quality Control checks include chemistry, physics, among other micro organic test, test sediments, and tap density measurements.
Test test micro organic include color, taste and smell. Sediment test is done by dissolving milk powder and poured milk solution through filter paper. Furthermore, wet filter paper fitted with filter paper samples with the standard A, B, C and D. A standard filter paper is a filter paper that has at least sediment, followed by a standard filter paper B, C and D. Tap density measurement is done by pouring milk powder with a certain mass into measuring cup. Furthermore measuring cup is vibrated 100 times, and obtained the volume of milk powder. Tap density is obtained by dividing the mass by the volume of milk powder milk powder.
2. Examination In Filling and Packing
Inspection of finished product, including:
 Packaging condition of aluminum foil, sealing conditions, aluminum foil code, folding box condition, code of folding boxes, labels, spoons, code of carton box, carton box condition, the contents of carton box, net weight, oxygen leakage.
 Finished Product Specification, performed as listed in the table.
These tests aim to determine the status of raw materials and products. Status is possible to select raw materials are released (acceptable) and reject (rejected), while for the product, which may be the status of NC (not used), released (can be used) and re-process (requiring re-process).

Making Milk Powdered

The principle of making powdered milk is as much as possible the evaporation of water content of milk by heating (drying) and through the stages of the process in order to get good results.
Stage of the process in the manufacture of milk powder, according Hadiwiyoto (1983) is as follows:

a. Pre-Treatment
Performed pretreatment include filtering or clarification, separation and standardization. Screening aims to separate foreign objects found in milk, such as dust, sand, feathers. Clarification is essentially the same as filtering, except that the clarification did not use a cloth filter filter but by centrifugation using CLARIFIER. Separation is intended to separate the milk into two components, namely skimmed milk and cream using a separator (Adnan, 1984). Separation aims to make the same milk composition by mixing milk-milk until homogeneous (Hadiwiyoto, 1983). The results of the pretreatment is condensed milk.

b. Heating
Before the drying process, carried out the process of concentration of milk by way of preliminary heating. Destination preliminary warming is evaporating some of the water contained by the milk until it reaches levels of approximately 45-50% just by using the evaporator and used to heat the air temperature from 65 to 177 ° C depending on the type of products made
(Hadiwiyoto, 1983).

c. Drying Process
Condensed milk drying process carried out by the type of spray dryer (spray dryer) and the type of cylinder (drum dryer). Condensed milk or dikabutkan sprayed with nozzle in a gust of hot dry air forcibly brought milk grains are very small until the grains finer powder (Williamson and Payne, 1993). Dry milk powder expelled from the spray dryer, while the hot air out from the side. Dry milk powder is shipped with the heat recovered by the cyclone separator or with a catch into the cloth bags or filters.

d. Packaging
After the drying process to be completed powdered milk, made the process of packaging. Milk powder is packaged and sold in the form of sachets / box or tin.

Milk Powdered | Definition

Milk powder is fresh milk which is evaporated all the water content. Nevertheless, milk powder still contains water in very small amounts, ie less than 5% (Hadiwiyoto, 1983).

Type of Milk Powder
Based on the milk is used as base material, powdered milk can be divided into:

a. Dry whole milk (full cream milk powder), a product obtained by evaporating water from fresh milk. This milk contains at least 26% fat milk and no more than 5% water

b. Dry milk or skim milk, produced by removing water and milk fat. Water content not more than 5% and fat levels are not more than 1.5%.

c. Dry butter milk, butter milk obtained from the evaporated water, a side product in the manufacture of dairy butter. When milk or cream be maintained at a certain temperature and stirring constantly, fat grains will agglomerate and form butter granules. Fraction of solid milk and water will be shipped with a wad of fat, whereas most of the fat and separate the byproduct called butter milk.

The properties of Milk Powder
Dried milk powder with a spray dryer irregularly shaped lumps which contain air cavities are small. Dried powder spray dryer with a more easily soluble in water if you have the size of 150 microns, below the size of the powder will float on the water and milk difficult to wet. Dried milk powder with a roll-drier has a serrated flake with a thickness of 15-20 microns.
Milk powder is very hygroscopic. If the humidity exceeds 25%, lactose will absorb moisture so that the milk powder becomes sticky. If the water content in the milk reached 80%, lactose will crystallize.
Requirements include powdered milk is a good solubility power, and no foreign odor (off-flavor). Solubility is affected by milk powder protein. Powdered milk protein content is strongly influenced by the nature of the warming and drying done. The form of milk protein casein and albumin are particularly vulnerable to warming at high temperatures. Temperature extremes can cause damage to proteins.

Damage of Milk Powder

Milk powder can be damaged due to poor storage conditions well. Damage that may occur include:
1. Fat Damage
a. Hydrolitic rancidity, damaged fat dikatalisa by the enzyme lipase and accelerated by the water. Rancidity more rare in milk powder by drying process roll for a high temperature in the roll-dryer has destroyed lipase enzyme activity.
b. Oxidized flavor, damage due to fat oxidation reaction with the outside air to form peroxides and aldehydes, giving rise to unpleasant smell (rancid). This damage can be prevented by packing milk powder in a vacuum or with inert gas is N2 to remove existing O2.

2. Non Fatty Compouns Damage
a. Damage to proteins that cause odor as the water content and high storage temperature.
b. The occurrence of lactose caramelize, the reaction between sugars with proteins or the outbreak of sugar into furfuraldehid and react with nitrogen gas. These things cause Browning.

Milk Powdered | Microorganisms in Dairy Industry

Microorganisms can cause damage to taste, smell and appearance of milk. Microorganisms are very influential in the dairy industry is a bacteria, yeast and mold.

Bacteria
Bacteria are single-celled microorganisms. There are several kinds of bacteria, which is round, rod and spiral. In the dairy industry, which many forms of bacteria found are round and stem form.
Each bacterial cell capable of doing their own metabolism. In the circumstances are not favorable, bacteria can protect themselves by forming spores.
Bacteria reproduce asexually by splitting themselves. Tues division of the size and shape have relatively similar to the early cells. In particular medium such as milk, the bacteria can produce cells of a new generation in half an hour.

Yeast
Yeast is a microscopic single-celled plants that have no chlorophyll, is larger than bacteria and live in groups on a regular basis.
Yeast reproduce by forming buds. Buds formed by the protoplasm of some stem cells and released as the new cells by stem cells. Yeast is not so important than bacteria in the dairy industry.

Mold
Mold is a multicellular plant which includes a low-level fungi. Mold shaped branching threads called Mycelium. Mold can reproduce sexually by cross exchange between cell protoplasm and asexually.

The influence of microorganisms on milk quality include:
Souring
Souring occurs because changes lactose into lactic acid as a result of enzyme activity produced by these microorganisms, especially lactic acid bacteria (Streptococcus lactis, Lactobacillus bulgaricus). Several types of yeast and mold can cause souring.
Souring and Gassines
Bacteria Escherisia colii and Aerobacter aerogenes producing gas and lactic acid and other acids that can agglomerate milk. It also formed other compounds that cause undesirable odor. Souring and Gassines can be caused by yeast.
proteolysis
Some microorganisms showed a tendency to break down casein. This solution is called proteolysis or peptonisasi. In general proteolysis produces odor, but the making of cheese proteolysis could produce a delicious aroma.
Ropyness
Activity of microorganisms in milk may result in a sticky substance such as gum, so that when the milk was poured from the container will occur shape that resembles a long string. The main cause of ropyness microorganisms are bacteria Alcaligenes vicosus.
Pigmentation
The bacteria can cause pigmentation in milk causing colors like blue, red, yellow and green. The colors are caused by pigment wore produced by the bacteria. Examples of bacteria that cause pigmentation is syncyanea Pseudomonas, Pseudomonas, and Serratia marcescens synxantha.
The development of these microorganisms can be inhibited by treatment at a particular temperature. Fresh milk processing to eliminate microorganisms including by way of:
1. Cooling at temperatures below 4 oC
2. Pasteurization at a temperature of about 62.5 oC for 30 minutes, so 90% of existing microorganisms in milk death.
3. Sterilization at a temperature of 105 oC for four seconds, so the expected elimination of all microorganisms.

Milk Powdered | Physical Properties of Fresh Milk

Physical properties of fresh milk is generally influenced by 2 factors, namely the composition and changes in the components it contains because of the damage or due to manufacturing processes (Adnan, 1984).

Color, Odor and Taste of Fresh Milk
Casein is a special protein found in milk with the content until it reaches about 80%. In a pure, snow white casein, odorless and does not have a unique taste. The white color of fresh milk casein due to the color (Buda et al., 1980). In the milk, casein is a colloidal dispersion, so opaque. Milk color slightly yellowish color caused by the fat contained in milk. Color is influenced by fatty substances dissolved in it, such as carotenoids which cause the color to yellowish fat (Lehninger, 1982).
Milk is a specific odor. Smell disorders such as milk can be checked for drug odor, sour smell, smell the smell of alcohol or other irregularities. Milk that smells of drugs is probably due to the addition of preservatives. While the smell of acid and the smell of alcohol that arise in the milk can be caused by the fermentation of milk caused by bacterial activity (Jenness and Patton, 1959).
Milk has a slightly sweet taste, because the milk sugar lactose in milk of about 4.8%. Lactose is a disaccharide that has a relative degree of sweetness of 16% when compared to sucrose which has a degree of sweetness of 100% (Lehninger, 1982).

Spesific Gravity of Fresh Milk
Specific gravity is affected by the levels of milk fat, protein, lactose, and minerals dissolved in the milk. Generally, in a solution, the more the compounds dissolved in it, the greater density. The weight of milk around 1027-1035 gram/cm3.

Fresh Milk Frozen points
Differences freezing pure water and milk is only about 0.5 oC, thus determining the freezing point of milk must be accurate if you want to know the dilution of milk with water.

Fresh Milk Boiling Point
The boiling point of fresh milk was associated with severe type. The higher the weight of milk, the higher the boiling point. Milk boiling point higher than the boiling point of water. The boiling point of pure water at sea level is 100 oC, while the boiling point of fresh milk is 100.17 oC (Buda et al., 1980).

Milk Powdered | Fresh Milk

Fresh milk is a product of the mammary gland obtained by the milking process. Breast milk is the stuff of high-quality food. Substance contained in breast milk has a very good composition, so that milk is good for the kids.
The composition of fresh cow's milk include:
• Water = 87.0%
• Fat = 3.9%
• Lactose = 4.9%
• Protein = 3.5%
Milk is a colloidal compound with water as a medium dispersinya. Water is the biggest components that make up the milk. Size of the fat content determines the quality of fresh milk. In milk there is dispersion particles. Coarse dispersion larger than 100 μ, the size of colloidal dispersion and dispersion 0.1-100 μ molecular size less than μ 0:01.
Ash in the form of white powder was formed as a result of burning the milk. Ash content of most is K, Na, Ca, Mg, Cl, P and S. The rest is metal compounds in small amounts.
Breast milk is good for bacterial growth media and non-pathogen pathogen. Therefore, milk does not last long if kept as it will quickly become sour and rot. Milk is attacked by bacteria harmful to health. Therefore, monitoring of breast milk, cleaning cages, food health and hygiene in cows pemerahannya process is needed.
Fresh milk than can be consumed directly, can also be processed into other products. With separator, milk can be separated into cream mostly fat and skim milk contains many proteins. Cream obtained can be made into butter (butter) and butter milk. Also milk can be processed into cheese, yogurt, and whey.
Chemical Properties of Fresh Milk

a. Milk fat
Milk fat consists of triglycerides, composed of one molecule of glycerol with three fatty acid molecules by ester bonds. Several types of fatty acids found in milk include: butyric acid, linoleic acid, linonenat acid, and oleic acid. In the milk, fat is an oil in water emulsion. Part of fat can be separated easily because the weight of small and solubility compared with water.
b. Milk Protein
Proteins are complex compounds of elements of atomic C, H, N, S, and P. Protein is a food that is very important in preparing the cell components, especially in the process of growth and development of living things. In milk protein content ranged between 2.8 - 4.0%. Protein consists of casein and whey proteins. The protein contained in milk consists of most of the casein, until it reached about 80% of the amount of protein. Therefore, casein milk protein is often called. Whey protein consists of albumin, membrane proteins and immunoglobulins. Immunoglobulin immune function to substances, contained in the resulting collustrum nursing cows.
c. Milk sugar (lactose)
Milk sugar (lactose) is a disaccharide composed of glucose and galactose with a bond from 1 to 4. One molecule of lactose is composed of one molecule of glucose and one galactose molecule. Lactose is a reducing sugar, which is in the nature pereduksinya first C atom of glucose molecules. On heating with high temperature, lactose react with a protein called caramelization reaction and cause the color brown (burnt) (Jenness and Patton, 1959; Lehninger, 1982; Adnan, 1984).
d. Acidity of Fresh Milk
Fresh milk generally has a pH between 6.5 to 6.7. PH values greater than 6.7 usually indicates a disturbance on the nipple, the opposite pH below 6.5 indicates the occurrence of damage due to bacterial milk (colostrum milk) (Jenness and Patton, 1959).
Power Reduction of Milk
Power reduction caused by the activity of milk enzymes as well as the specific bacterial activity. Based on research results, obtained the relationship between the number of bacteria in the milk at the speed of the reduction of milk. Power reduction of milk can be tested by using a solution of methyl blue or reazurin solution. Methyl blue concentration in solution is 1 percent. The way the analysis is as follows:
1. Preparing as much fresh milk in a 10 mL test tube.
2. Adding a solution of methyl blue 1% in increments of 1 mL.
3. Heated in an incubator at a temperature of 37 oC.
4. Observing the length of time until the blue color disappeared.
The longer the loss of blue color indicates the number of bacteria that have less and less. This shows the better quality of milk