Evaporation of liquid milk into sweetened condensed milk

Evaporation is a process of removal water from liquid foods which concentrated liquid products. Advantages of evaporated liquids are longer shelf life, decreased volume and weight, easier for transportation, less changes during prolonged storage and smaller storage space. These are due to removal of water decreasing the volume and weight of liquids and thus inhibition of microorganisms growth.

 Two types of evaporator used which are plate evaporator and falling film evaporator. Advantages of plate evaporator are relatively low capital cost, high operating efficiency, easily control plant, permits fully automatic operation, can handle more viscous liquids and best suited for highly sensitive products. The advantages of falling film evaporator are operations can be at lower temperature, lower energy consumption, easily maintenance and simple construction of the plant.

Sweetened condensed milk is the concentrated milk where sugars added as preservative, sweetener and thickener. It contains around 8%fat, 45%sugar an 20% solid-non-fat. Sugar can effectively increase the osmotic pressure of products, hold the water and thus prevent microbial spoilage. Sugar is a natural sweetener where it imparts sweetness. By adding in sugar, it acts as thickener to provide a desirable viscosity and improve the solubility if lactose.

Diabetes Melitus

Diabetes mellitus is a food associated diseases which body cannot use glucose properly because lack of insulin or its proper function. Thus, basically blood sugar is abnormally high in the patient. Under this condition there is increased breakdown of liver glycogen, defective storage of glucose in muscle and defective utilization of glucose in the tissues. Hereditary may is a predisposing factor.

Common symptoms include polydipsia (extreme thirst), polyphagia (constant hunger) and polyuria (excessive urine). Diabetes mellitus can be categorized into two forms which is insulin-dependent diabetes mellitus (IDDM) and noninsulin-dependent diabetes mellitus.

IDDM is due to insufficient endogenous production of insulin and thus tend toward ketosis and ketoacidosis where face flush, acetone breath, respiration increase and labored and dehydration. For IDDM, insulin treatment is required. The patients have to consume carbohydrate in conjunction with insulin in order to avoid consequences. In case of slow release of insulin, pattern of small meals is recommended.

NIDDM is second type of diabetes which include 90& of all diabetes. It is due to ineffective usage of insulin or inadequate insulin. It occurs in adults especially the one who obese. NIDDM caused by hypersecretion of amylin, problems with insulin receptor or fat, low fiber abd excessive sucrose in diet. Thus, patient with NIDDM should reduce consumption of glucose, sucrose and other simple sugar, replacing some of carbohydrate with monosaturated fat or with fish oil and intake of adequate fiber and pyridoxine. 

Energy Balance

Energy balance is defined as a balance exists between the energy taken in as food and the various energy forms used by human. If the energy balance is perfect, the weight will remains constant. If the energy taken excess the energy expenditure, it will stored in the body in form of fat. Energy intake less that energy used and the difference is made up by burning fat in body.

Organism’s source of energy is chemical energy supplied by foods where the oxidation of foodstuff provides chemical energy for cellular reactions. When nutrients are broken down, about 40% is captured in form of ATP.

Energy in nutrition is defined as the amount of heat necessary to raise temperature of one kilogram of water to one degree Celsius. Measurement of energy expenditure can be done using direct calorimeter or indirect calorimeter.

Direct calorimeter is the direct measurement of the actual energy expended by the body throughout a given period. The heat given of by the human subject in a special calorimeter is absorbed by the water in the coils surrounding the well-insulated chamber. Thus, the total heat may be measured directly.

For the indirect calorimeter, the rate of metabolism or heat production is calculated through the oxygen intake and carbon dioxide content of the expired air as measured by a respiration apparatus. This may apply to various type of activities or when lying at rest.  

Ice Cream Production

Production of ice cream includes the blending of mix ingredients, pasteurization, homogenization, aging of the mixture, freezing, packaging and hardening. Selection of ingredients is based on the desired formulation. Liquid ingredients are heated and add with powdered ingredients such as skim milk powder and sugar, followed by adding of stabilizer and emulsifier. Fat is the last item to add in. Normally, high shear mixer are used in blending because the premixing the powder ingredients is not necessary, agglomerate free mix, stable emulsion, rapid mixing times and maximize yield of raw material as thickening agents are fully hydrates and other ingredients are fully dispersed. 

Pasteurization is to destroy the pathogenic bacteria, reduce spoilage organisms and hydration some of the components. It can be batch pasteurized or continuous pasteurization. Homogenization is done in two stage where formation of fat emulsion by breaking down milk fat globules to <1 µ m. This is followed by the reducing cluster of the fat. Ageing is allowing time for fat to cool down and crystallize while the protein and polysaccharides can be fully hydrated. Ageing can improves the whipping qualities of mixture, body and texture of ice cream. 

Freezing can be done using the barrel freezer. Hardening is done in hardening tunnels or contact-plate freezers. Factors affecting hardening time are freezer temperature, rapid circulation of air, container size, ice cream composition and package materials. 

Ice Cream Introduction

Ice cream is an enormously popular food where cover a wide range of frozen dessert. Dairy ice cream is generally defined as frozen mixture of a combination of components of milk, sweeteners, stabilizers, emulsifiers and flavoring. Some terms are used for ice cream such as reduced fat ice cream, light ice cream, low fat ice cream and nonfat ice cream. The texture properties of ice cream must contain certain amount of air; otherwise it will be hard, palatable and solid block. It should melt without feeling too cold and melted products are neither too liquid nor too viscous while the ice cream should not have a poor melting. Besides, ice cream must be smooth in texture instead of sandy. Production of ice cream including the blending of mix ingredients, pasteurization f mixture, homogenization, aging of the mixture, freezing, packaging and lastly hardening. Ice cream produced can be classified into two types which are soft ice cream and hard ice cream. Soft ice cream is the one which is soft and consumed immediately after freezing the mix. Hard ice cream is much firmer product, excellent in quality, longer shelf life and being hardened after freezing the mix.

Lipids

Functions of lipid in our body are as body insulators, protect organs from trauma, energy reserves, feeling of satiety, supply essential fatty acid for maintenance and growth, precursor of sex and adrenal hormones, formation of vitamin D, carrier of fat soluble vitamin A,D, E, and K, and provides flavor and palatability of foods. Factor affecting the digestion and absorption of fats are age, physical nature, present of emulsifier agent, health of intestinal lining, cooking temperature, present of dietary mineral and bile or enzyme production.

Examples of lipid in our body are lipoprotein and cholesterol. Lipoprotein is divided into three types which is very low density lipoprotein (VLDL), low density lipoprotein (LDL) and high density lipoprotein (HDL). VLDL is used to transport cholesterol and it is normally converted to LDL. LDL is carrier for cholesterol which has about 25% protein and 75%lipid. It has great affinity toward artery walls and thus increases the risk of arteriosclerosis and cardiovascular problems. HDL have 50% apoprotein and smaller to LDL. It carries tissue esterified cholesterol to liver, fostering the conversion f cholesterol to bile salts, block the uptake of LDL and facilitate blood enzyme to esterify free cholesterol to make it less likely to enter tissue. HDL is healthy cholesterol. Disorders related to the lipid are fatty liver and gallbladder stones in billary tract. 

Protein

Protein has many functions in our body, for example it is used as apoprotein, maintain the fluid and electrolyte balance, as buffers, immunity response, provides energy, growth and as hormones. Excessive intake of protein will induce fluid imbalance since more water is needed, liver disturbances and shorter life span due to toxicity by products. Besides that, excessive intake of protein will make our body loss calcium. The breakdown of protein to sulfur containing amino acids causes the urine becoming more acidic, forcing it to carry out more calcium with the excess protein. Several disorder related to protein are homocystinuria and phenylketonuria. Homocystinuria is due to lack of cystathionine synthhetase where accumulation of methionine and homocysteine cause atherosclerosis. Phenylketonuria is disease lacking of phenylalaline hydroxylase where accumulation of phenylalaline damage brain and mental retardation.

There are some terminology for protein, such as protein efficiency ration, biological value and net protein utilization. Protein efficiency ration is defined as a measure of protein quality assessed by determines how well a given protein to support weight gain in laboratory animals. Biological value is the measure of the nitrogen retained in the body divided by the amount of the nitrogen absorbed from protein. Net protein utilization is the ratio of amino acid converted into protein compared to the ratio of amino acid supplied.