Preparation of raw material and sheduling the mixtures.

The mixture is prepared in raw materials to long pasteurizing (NDM) or in capacitive pasteurizer with mixer. In the first place load the fluid components (water, milk, juice from fruit and berries), solution warm before the temperature 40-45°С, providing most full and quick dissolution. Then contribute the dry components (sugar-sand, stabilizers), thickened milk and "cream butter. It is impossible allow the dissolutions a component at the temperature above 60°С, since herewith is not excluded possibility brewing protein and melting fat.

Filitering, emulgation and pasteurizing of the mixtures. For removing from mixture insoluble wads cheese and possible different mechanical admixtures its filter (after dissolution component and after pasteurizing), using disc, plate, cylindrical and the other filters. The filterring material in filter seasonly clean or change, not allowing concourses of the big mass setting.

Emulgation necessary to conduct in that event, when milk ice-cream work out with cream mask for the reason its even distribution on the whole volume. The mixture warm before the temperature 60-65°С, contribute the butter and conduct emulgation by means of special equipment.

Pasteurization of ice-cream mixture promotes the good mix and components dissolution, as well as creates the best conditions for homogenization. The pasteurization is conducted at the temperature 85°С.

Homogenization of mixtures. Filtered mixture ice-cream after pasteurizing enters in homogenizator for additional processing. The process homogenization promotes increasing beat up mixture, perfects the consistency ready ice-cream and will add it gentile structure.

For ensuring the even crushing fatty ball at homogenization big importance has a condition not only heads, but also valve of the cylinder. Herewith in soaking up or pumped valve can be an instant falls of the pressure, as a result part mixture will get through head it is not enough homogenized. So it is important to provide the good condition homogenization heads and work homogenizators under constant pressure. In no event it is impossible allow that part mixture remained without homogenization. The following stick fatty ball raises viscosity a mixture and slows the process beating, at structure and consistency of the ready product several grows worse.

Homogenization influences upon some of these power, but consequently, and on forming the fatty particles (the wad). In the event of presence big amount fat in small space possibility of the collision ball and their stick increases. The intensity of the forming the fatty concourses is found in inverse dependency from the temperature homogenization. Consequently, it is impossible homogenize the mixture, containing big amount of fat under low temperature.

The other function homogenization is concluded in stabilizations shell fatty ball. For building new shell are successfully used milk proteinss - casein and wheys of the protein. The temperature 75-85°С are an optimum mixture for homogenization ice-cream, at between molecular of power weaken and molecules of casein gain the mobility.

 

Cooling and maturation of the mixtures. The homogenized mixture quickly cool before the temperature 0-6°С (by means of plate, irrigation chillers and automated installation) for the reason making the disadvantage conditions for vital activity microorganism, as well as for preparing mixture to the following process of the processing - a maturation.

In process of the maturation occurs hydration protein milk, stabilizer and emulsifier, the most further adsorption different material, being kept in mixture, on surfaces fatty ball. Besides, at reduction of the temperature before 4°С occurs hardened milk fat and crystallization of the emulsifier - monoglicerides.

The purpose of the maturation mixture is increasing its beating and improvement to consistencies ready ice-cream.

Freezing mixtures. Freeze mixture is one of the the most important stage of the fabrication ice-cream, conditionning quality ready ice-cream. The composition mixture, its condition, velocity and degree of the freeze define the reception an ice-cream small crystalline of the structure and gentile consistency. The best way of the freeze mixture with reception milk ice-cream high quality is a freeze in freezers unceasing or periodic action. Freeze mixture ice-cream in freezer name the process freezing. The air is sated during freezing mixture under simultaneous partial freeze.

For ice-cream is reached beating - 50-60%.

In process freezing is formed new phase (the crystals ice and fat), prepared layer of the fluid phase. The structure and consistency of the ready product hang From correctness of the undertaking of this process.

The structure milk ice-cream is characterized amount crystal ice, amount of the introduced air and its dispersion i.e. amount air bladders. Than small crystals ice and bladders of the air, that gentile structure milk ice-cream. The crystals ices do not come to light when using the product, having amount less 50 mkm.

The ice-cream under insufficient beating is got too thick, with rough structure and consistency. The ice-cream with high beating melts slowly.

The process of the freeze mixture realize in special device - an freezers unceasing and periodic action.

The process freezing mixture occurs as follows. The consequences crioscopycal temperature - water in mixture ice-cream begins to change in the most small crystals ice. Herewith in unfrozen part moisture increases the concentration of the solutes (the sucroses, lactoses, mineral salts) and is lowered temperature of the freeze. The process freezing occurs under gradually lowerring temperature of the product.

Forming in cream frozen in process freezing air bladders, their dispersion, uniformity of the distribution, three-dementional share of the air in product render the big influence upon structure and gustatory value ice-cream.

The mixture must enter in freezer with the temperature not above 6°С. The temperature ice-cream when leaving from freezer usually forms -3,5-(-6°С).

Packaging and hardening of ice-cream. Coming out of freezer ice-cream quickly pack and immediately direct on hardening, since at delay part crystollized water can thaw that will hereinafter bring about formation large crystal ice. In process of the freeze mixture in freezer occurs only partial freeze of water (in freezer periodic action is frozen beside 35% water, but unceasing action - before 55%), ice-cream has else weakened consistency. In addition freeze or "hardening" milk ice-cream for giving him it is enough thick consistency in freezers device.

Questions:

1. What is flavour and smell of dairy butter specified by?

2. What stages does technological process of butter manufacture include?

3. What method is used at concentrating of fat phase by skimming and subsequent breaking of milk fat emulsion?

4. In what line are high fat cream separators for high fat cream included?

5. What is the function of homogenization?

 

 

Lecture 15, 16. Food preservation

1. General definition of fruit and vegetable preserves

2. Advantages and disadvantages of preserves.

3. Technology of vegetable natural pack.

4. Technology of production of natural preserves from green peas, tomato, corn and related raw material.

 

Marrow, custard squash -кабачки, патиссоны; asparagus fern, artichoke- спаржа, артишоки; sorrel, spinach- щавель, шпинат; stannum-олово; puffer, swell –бомбаж.

1. Food preservation is the treatment of food, permitting to prevent their spoiling on long storage and keep at that nutritive and flavor properties. Product spoils first of all under the influence of microorganisms and various enzymes entering into the composition of nutrient materials. All methods of conservation are founded on destruction of microorganisms or suppression of their activity, destruction of enzymes or development of disadvantageous conditions for their activity.

To thermal methods of conservation sterilization, pasterurization, cooling, freezing belong. Sterilization is carried at temperature 100⁰C and up under pressure in air-locked tin or glass can, at that not only vegetative forms of microorganisms, but also spores perish. Sterilized preserves can be stored at some years. At that method of conservation vitamins partially break, proteins coagulate. Pasterurization is carried by way of heating of product to temperature 65- 95⁰C. At that only vegetative forms of microorganisms perish, but composition and product quality change not large.

Milk, cream, some vegetables, fruit and berry juices are subject pasterurization. Cooling of food products is carried in cooling chambers at temperature about 0 °. Most often meat, fish, egg, dairy products are conserved by cooling. Freezing is carried out in special freezing chambers at 18 -32°, shelf life of such products is to 1 year and more. At freezing of meat, fish and poultry part of moisture from cells of muscular tissues separates, which freeze in intercellular space in the form of small crystals, therefore to avoid nutritive losses defrosting ought to conduct slowly.

Dehydration is used for conservation of milk, egg, fish, vegetables and fruit. In industrial conditions vacuum drying, providing full safety of food products is used. One of types of vacuum drying is lyophilization, or sublimation drying, i.e. dehydration of prefreezed product in conditions of vacuum and moisture removal directly from ice crystals, by-passing liquid phase. Air-sunlight drying of fish belongs to preservation by dehydration.

Curing and conservation using sugar is founded on that salt and sugar extract water from product and create disadvantageous conditions for development of microorganisms. Usually 8 -12% of salt brine and 60% of sweet water are used. Milk, fruit, berry and products of their processing are conserved using sugar.

2. Disadvantage of conservation by sugar consists in that product, subjected to such processing; there can be no long-time storage, i.e. on sugar medium yeast fungus and mold well advance; in addition to, and at use of these products abundant number of calories and redundancy of sugar enter in vivo.

Disadvantage of curing is loss by product some nutrient materials, which get away in brine, and also entry of salt in vivo. Marinating is founded on that majority microorganisms perish in acid medium. For marinating solution of acetic acid in concentration from1,5-2% to 4-6% to mass of product is used. Marinated foods keep at low temperature. At fermentation of vegetables bacteria, which are on the surface of fruit and vegetables, ferment sugar, contained in product, and form lactic acid, also suppressing activity of microorganisms. Used at that cooking salt suppresses micro flora at the beginning of fermentation (before formation of lactic acid). Flue-curing (копчение) is used for conservation of meat, fish and other products. Except traditional fume smoking also harmless smoking fluids are used. Smoke products, as well as salted, are kept at temperature about 0⁰.Conservation using conserving agents as antiseptic agents and antibiotics is founded on suppression of development in food products microorganisms. Sterilized preserves, hermetically sealed in glass or metal cans with anticorrosion covering nicely keep product quality. Manufactured date, kinds of preserves and information about production plant and batch of preserves are pointed out on cans. This data is necessary for control of quality and inquiry of poisonings. During long storage of preserves changes of chemical composition (decrease of ascorbic acid’s content and others) and organoleptical properties are possible in them. Minimal losses of ascorbic acid are registered in use of cans of sufficient high vacuum (345—400 mm hg) and at compact filling of them by product. In the time of sterilization and keeping of canned goods passage of metals from cans’ wall and their covering into foodstuffs can take place in consequence of destruction of covering layer- stannum. As a result of interaction of metals with organic acids of product in cans hydrogen accumulates, considerable quantity of which induces puffer (chemical, hydrogenic). Other cause of swell (бомбаж) is development of microorganisms in insufficiently sterilized preserves. For lowering of internal corrosion metal cans are topped by varnish (лак), which possess stability to corrosion, induced by organic acids. Together with sterilized preserves so-called preserves or semipreserved foods are produced. Products, conserved by salt, vinegar, sometimes using antiseptic agents and sealed in glass or tin tare aren’t subjected to sterilization; therefore their shelf life is limited. They are stored at low temperatures.

3. Technology of vegetable natural pack VNP is fully prepared to use semi-finished preserves, designed for further usage as components of salads, soups, garnish and other catering production. The distinctive feature of VNP is that vegetables in the time of processing take minimal heat treatment or go without it. VNP can be made from one vegetable type; solutions of basic nutrient materials (sugar, salt, acids, natural juice, chopped or strained vegetables of the same kind) serve as filling for VNP; content of basic nutrient materials in filling don’t exceed content of these matters in raw material; organoleptic indicator of VNP depend only upon quality of raw material and in technological process don’t form; VNP have low caloric content, is free of provocative additives and is usable as dietary product. VNP is produced from leguminous (pea, bean), cereals (corn), tomatoes (tomato, pepper), cucurbits (pumpkin, marrow, custard squash), dessert (asparagus fern, artichoke), roots (carrot, beet), potatoes, sheet-like (sorrel, spinach). By appearance of VNP can be: from whole vegetables; from cutted vegetables and as puree or paste.

Technological processes are divided into several stages: 1) preparation of raw material; 2) preparation of filling; 3) prepackaging, hermetization, sterilization; 4) marketable appearance.

4. Green peas. Grains go follow processing: 1. primary purification from fine impurity on separator 2. washing in water 3. inspection on transporters, when deformed, small fruits are sorted 4. blanching in water and cooling (1-3h) 5. cooling in brine and second sorting, whereby part of bran coating and hyper mature grain are separated. 6. second inspection 7. prepackaging Can with peas are filled up by filling, which represents water solution of sugar 3% and salt 3%. Filled cans are seamed and sterilized at 120 ⁰C and 130 ⁰C, after which cooled.

Green bean is tinned as whole or cutted pod

Technological schema

Quality grading

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Washing

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Blanching in water at t=85 ⁰С

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Cooling in water

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Removal of tag ends, long pods are cutted on bits and pieces by size 2- 2,5 sm

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Prepackaging

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Filling by hot (80 ⁰C) 3% salt brine

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Seaming

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Sterilization at 116 – 120 ⁰С (accordingly in glass and tin container)

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Cooling

 

Questions:

1. What is the name of food processing, which allows to prevent spoilage during storage and still maintain the nutritional and taste qualities?

2.How spend preserving chemicals (sorbic and benzoic acids)?

3. Why sterilization using high temperature?

4. What system of protection against the adverse effects of the environment, called the immunity has plant material as a whole and each individual cell?

5. Which method is most common in the production of canned food?

Lecture 17, 18 Vegetable and fruited marinades.

1. Assortment and peculiarities of vegetable and fruited marinades

2. Technology of production of marinades.

3. Requirements to raw material.

4. Processes of pickling, salting and retting of vegetables and fruit.

 

1. Vegetable and fruit marinades. Marinade is product from vegetables or fruit with filling, as part of which acetic acid enter. Besides, filling includes salt, sugar and spice. Constituent of vinegar pickle is selected so that they provide required taste of. Acetic acid renders preservative activity, which is caused by rise of product’s active acidity.

Considering influence of acetic acid on taste of product at marinating of vegetables or fruit, it is used in concentration not above 0,9%. Such concentration is insufficient to prevent product from spoiling. Therefore marinades are produced in sealed container and pasteurized. For marinades vinegar is used, i.e. solution of acetic acid with concentration 3-6%.

Vinegar, extracted from vinegar essence, differs by strong taste. Therefore for production of marinade it is desirable to use biochemical vinegar. There are distinguished next types of biochemical vinegar alcohol, fruit-berry, malty, aromatic. Biochemical vinegar results acetic acid fermentation spirit. Under action of bacteria Micoderma aceti ethyl alcohol passes into acetic acid.

For production of marinade follow vegetables are used: - cucumber of right form with solid peel and abortive seed; - small-fruited custard squash with abortive seed; - tomato foxy or green, preferably small berry; - eggplant of cylinder form not above 60mm, with abortive seed; - marrow squash l=110mm and d to 60mm, with solid elastic flesh and abortive seed; - red pepper sweet thick-walled, l=70mm and more; - cauliflower. As well as white and red cabbage, runner beans, beet, onion, garlic, portulaca, horse radish are used. Mainly subacid marinads are produced. For production of acid marinade colored and green head cabbage, garlic, onions are used.

2. Most common kind of vegetable marinade is canned cucumber. For production of these preserves immature tender cucumber with underdeveloped seed are used. Cucumber must be of a regular form, green. It is not assumed in processing withered cucumber, deformed, overgrown, and with mechanical damage, very dirty, injured by various diseases and agriculture pests. Length of cucumber, conserved as whole fruit, must be not above for extra grade 70mm, upper 90, I-110mm. Large cucumber length to 140mm and to 50mm with underdeveloped watery seeds also make I sort, but quality of such product is lowered.

Graded cucumber are washed and soaked in cold pure water during 5hour for removal of air, containing in tissues. On keeping in water air is spent on breath. Soaking provides preservation firm texture of cucumber, which without such processing differs at sterilization. Disadvantage of soaking is extension of technological process, installation of large-capacity vats and considerable production area. Therefore soaking is replaced by holding cucumber during 3-5h in water t 60⁰C. At that from surface of cucumber waxy layer moves away, this raises their permeability to water. In order to avoid cooking they are cooled.

Prepared cucumbers are washed and inspected, pedicles are removed. Then cucumbers are containerized. On bottom of can put green, spice, then cucumber. Full tare is filled by hot solution, containing cooking salt (6-7%) and acetic acid (1%). Acid is added to brine just before filling it in cans. Full cans are sealed and sterilized at 100⁰C. Productivity of sterilization depending on of tare material is from 5 till 15. After sterilization product is cooled.

Quantity of cucumbers in preserves 50-55%, spice and green - 2,5-3,5% to net weight of preserves. Salt content in end product is 2,5-3,0%, total acidity is 0,4-0,6%.