A report on task performance.

The content

Introduction………………………………………………………………………………………...6

Laboratory work # 1 Definition of oxidation of dairy butter. ……………………………………..7

Laboratory work # 2 Quality assessment of bread and bakery products.………………………….9

Laboratory work # 3.Definition of physicochemical

parameters of sugar-beet. …………………………………………………………………………10

Laboratory work # 4. Research of assortment and estimation

of mayonnaise quality.……………………………………………………………………………..14

Laboratory work # 5.Quality determination of cocoa powder

аnd chocolate……………………………………………………………………………………....16

Laboratory work # 6 Definition of phenol compounds

in vegetable products.……………………………………………………………………………...19

Laboratory work # 7.Definition of content of ascorbic acid

by iodimetric method……………………………………………..………. ………………………21

Laboratory work # 8. Analysis of reducing properties

of ascorbic acid…………………………………………….……………………………………….24

Laboratory work # 9.Definition of fats mass share in cans by refractometric method

and total acidity in canned goods with sour fillings…………….……...……………………….26

Laboratory work # 10.Definition of calcium content in food products….……………………......30

Rules of safety measures…………………………………………………………………………...38

Literature…………...………………………………………………………………………………39

 

Introduction

In consequence of systematic study of discipline «Processing productions safety» students solve following objectives: safety of food products and their production from the point of view of health and reliability for the people and environment, estimation methods and safety criteria for food production, microbiological safety quotient of food production, risk of disadvantage or superfluity nutrient materials, danger of xenobiotics from ambient medium, main criterion of safety food additive, mainstream industry article development of food in ХХI century, definition methods of content toxic elements in food products.

Laboratory workshops are connected with theory. On practicum students fortify obtained theoretical skills, get hand-on experience by definition of process specifications of preparation and delivery of ready-to-eat meal in accordance with applicable standards, norms and other scientific and technical documentation.

It is essential that students learn to economize chemical reagents, carefully refer to laboratory apparatus and facility, and follow regulations of personal hygiene and prophylaxis, safety procedures.

 

Laboratory work #1

Definition of butter fat oxidation level.

Purpose of the work: experimental determination of butter fat oxidation level

1.1. The task

1. Define oxidation level of dairy butter.

2. Calculate real optical density by formula.

3. Draw up report about the effort.

Theoretic part

Method is founded on formation of colored compounds of 2-thiobarbituric acid with some of secondary products of oxidation fat. Color grade depend upon oxidation rate of fat, as a result of which aldehydes form. Main of last is molon aldehyde. In absorption spectra of colored compounds there are two maximums, where the first (450 nm) corresponds yellow colored condensate of 2- thiobarbituric acid with monoaldehydes, but the second (535 nm) - red colored union 2- thiobarbituric acid with dialdehydes.

The given reaction is widely used for degree evaluation of vegetable and animal fats oxidation, owing to high sensitivity, reproducibility and correlation of this index with organoleptic estimation of fat freshness. Due to the fact that mechanism of this reaction is unknown fully, analysis results are expressed by per unit of absorbance. Analysis of fat oxidation degree of various products with 2-thiobarbituric acid differs by distinction of sample preparation for measurement of absorbance by spectophotometer Especially it concerns the method for discriminating of fat.

Technique definition.

Chemical reagents: 1n spirit of salt; petroleum ether; reagent of 2-thiobarbituric acid; extraction mixture (isoamyl alcohol and 99% pyridine in balance of volumes 1:1).

Weighed portion of dairy butter (10g) is settled in centrifugal test-tube with stoppered and is hold in hot water with temperature 70-80 gr C during 3 min for complete fusion of milk fat. Next 2 ml of distil water,1 ml of 1n spirit of salt are added in test-tube, then it is shacked up strenuously, reheated 1 min and centrifugated 3 min (about 5000 rounds per min). Layer of milk fat is pipetted off. Water fraction is cleaned by several portions of petroleum-ether until disappearance of visible slosh. The ether every time is deleted by pipette with pumping out rubber bulb. In the end of flushing out contents test tube is centrifugated 2-3 min for more complete dissection of ether. 1,5 ml reagent of 2-thiobarbituric acid adds in caught-on of water fraction and then it is hold on boiling-water bath 15 min. Test tube is quenched to 18-20 gr C,

5 ml extraction mixture is added, then strenuously shaken and centrifugated 10 min by 5000 rounds per minute.

Clear color solution is carried over by pipette in cuvette 1cm,then optical density is measured under λ =490Nm, 535 Nm and 580 Nm. Control experiment is prepared in simulated conditions, but without butter, and 3,6 ml water instead 2 ml is added taking into account humidity of dairy butter.

Calculation of real optical density of colored compounds is carried by formula:

D=D535- D490+ D580,

where D535 - maximum absorption of colored compounds under λ =535Nm,

D490 и D580 - minimal absorption in spectrum of determined colored compounds under λ =490Nm, 580 Nm, their optical density is minused for liberation from phone.

Laboratory work #2

Theme: an estimation of quality of bread and bakery products

The purpose of job: To carry out an estimation of quality of the offered samples of bread and bakery products by organoleptical, physical and chemical parameters.

1.1. The task

1. Define an estimation of quality of bread and bakery products.

2. Learning of bakery products defects.

3. Draw up report about the effort

Theoretic part.

Potato bacillus, molding of bread and other diseases, called by wrong keeping and processing of charge stock, can induce diseases of man. In aid of food safety in the manufacture of bread it is necessary to use quality products, passed off microbiological and physicochemical check-out. End products also must compliant with standards.

Laboratory work # 3

Definition of physicochemical parameters of sugar-beet.

Purpose of the work: experimental determination of physicochemical parameters of fruits and vegetables.

1.1. The task

1. Define physicochemical parameters of fruits and vegetables.

2. Calculate content of ascorbic acid by formula.

3. Draw up report about the effort.

Definition of titrable acidity.

Theoretic part

Titrable acidity of fruits and vegetables characterize taste and food value of product. Fruits and vegetables content several acids, but only one of them predominates. So, apple acid predominates in seed-bearing fruit, beet, and carrot. Citric acid predominates in citrus plants, grape, potatoes, raspberry, cranberry and others. Definition of titrable acidity is based at ability of alkali to neutralize quantitatively as free acids as their salts in researched solution. According to quantity of alkali it is necessary to re-count it according predominated acid.

Technique definition.

Necessary materials and facility:

1.Fruits and vegetables. 2.Porcelain cup. 3. Measuring flask. 4. Counter balance. 5.Litmus- paper.

6. Glass rod. 7.Boiling-water bath. 8. Chemical reagents for titrating.

At Counter balance weigh 25gr of pulp in porcelain cup and put it into 250 ml’ measuring flask through feeder with the help of glass rod, adding some water in order the volume of it was 2/3 of flask volume. Then content of the flask heat on boiling-water bath to 80⁰C and hold it 10-15 min. After quenching of flask’ content add water till mark and filter. 50ml of gotten filtrate carry over by pipette into cone flask, add 3 drops of phenolphthalein and titrate by 0,1n alkali until pink color. If filtrate is colored, litmus- paper as indicator can used. Titrating ends, if the drop of liquid doesn’t color litmus- paper to red.

Calculation of titrable acidity of fruits and vegetables (X_t) is carried by formula:

X_t=V·K·K₁·V₁·100/m·V₂ , where

V-consumed at titration quantity of 0,1n alkali, ml;

K-correction coefficient of alkali concentration;

K₁ - correction coefficient of corresponding acid; for apple acid - 0,0067; for lemon acid-0,0064; for tartaric acid-0,0075;

V₁- volume of extract, prepared from weighed amount of being investigated product, ml;

100-correction coefficient of 100g of product;

V₂- volume of filtrate of being investigated product, taken for titration, ml;

m-weighed amount of product, g.

Technique definition.

Definition of solids content in plant fruits and vegetables conduct as follows: take some drops from pushed up juice and infiltrate it. Then on center of refractometer bed knife lay on a drop of juice by glass rod, but set aside a knife edge. For every sample conduct at least three measurements and output average from obtained rate.

Processing of results.

After account by scale register evidence of thermometer, incorporated in refractometer, in order to correct temperature. Temperature correction is included in case when there is difference between temperature at the moment of definition and temperature, wherein is graduated scale of refractometer.

 

For correction of received data use table 1.

 

Temperature, ^оС	Solids content, %
	Take off evidence
0,25 0,21 0,16 0,11 0,06	0,27 0,28 0,18 0,12 0,07	0,31 0,26 0,20 0,14 0,08	0,34 0,29 0,22 0,14 0,08	0,35 0,31 0,23 0,15 0,09	0,36 0,31 0,23 0,16 0,07	0,36 0,32 0,23 0,16 0,07
Add to evidence
	0,06 0,12 0,18 0,24 0,30 0,36 0,43 0,50 0,57 0,64	0,07 0,14 0,20 0,26 0,32 0,39 0,46 0,53 0,60 0,67	0,07 0,14 0,20 0,26 0,32 0,39 0,46 0,53 0,61 0,70	0,77 0,14 0,21 0,27 0,34 0,41 0,48 0,55 0,62 0,71	0,07 0,14 0,21 0,28 0,36 0,43 0,50 0,58 0,66 0,74	0,07 0,14 0,21 0,28 0,36 0,43 0,51 0,59 0,67 0,75	0,07 0,15 0,22 0,30 0,38 0,46 0,52 0,63 0,71 0,80

Definition of sugar content. For determining of sugar prepare water extract from gritted masses of fruits and vegetables. Extract must be prepared with such account, that after attenuating- разбавление, connected with clearing of solution, they contain from 0,25 to 1% of sugar.

Technique definition.

From gritted average sample take and weigh on counter balance 25 g of(cabbage, tomato, potatoes) in previous measured porcelain cup. Carry over a weighed amount through funnel into 250 cm³’ measuring flask. Float out adherent particles. Pour over sample by distilled water with such account, that total volume of sample and water does not exceed 150 cm³. Then put down a bit of litmus paper into flask and neutralize liquid carefully by 15-percentage soda solution until litmus paper become dark blue (deacidification is carried out for warning of sucrose splitting). After neutralization of liquid heat flask, which is continuously shaken, on boiling-water bath by temperature 80^оС during 30 min for the more full and fast transition of sugar into solution. After quenching contents of flask add 10-15 cm³ 30-percentage solution of lead tetraagetate, carefully shaking up contents of flask and give to defecate, but then bring in yet 1-2 drops of reagent.If at that dreg forms in free liquids, it is necessary to continue addition of lead tetraagetate in solution. It is carried out for removal protein, pectic, tannic and some other matters, which block definition of sugar and distort analytical results. When reached full clearing of solution (at the bottom of flask must be dense deposit, but over it must be transparent liquid) flask contents put across mark and filter through fold filter. Obtained filtrate contains abundance of lead, which is deleted by fat solution of sodium sulphate. For this purpose transfer 100 cm³of filtrate in flask of 200 ^оС volume, add 10-20 cm³ of saturated solution of sodium sulphate and shake up. After 5 min carefully stick by wall of flask precipitation agent- natrium sulfurous (Na₂SO₄), then check fullness of lead precipitation. If sludge doesn't form, contents of flask put across mark, shake, give sludge to go down and filter it through paper filter, if it is possible don’t carry there sludge. This light filtrate, called solution "A", answers for determining of reducing sugar, but after sucrose splitting-of saccharose.

Theoretic part

Except for physical-chemical parameters at realization of examination of quality of mayonnaise define parameters of safety. The list of these parameters according to the hygienic requirements of safety is given in tab. 33.1 of a theme 33.

Definition of a mass share of a moisture. There are two methods of definition of a moisture in mayonnaise: arbitration and accelerated.

Necessary materials and facility:

1.Samples of mayonnaise. 2.Oleometre. 3. Boiling-water bath, centrifuge,balance and desiccator.

4. a sulfuric acid (density 1,5 g/sm³); isoamyl spirit, caustic alkali, phenolphthalein, the sand which has been washed out and calcined.

Laboratory job № 5

Theme: Estimation of quality of cocoa powder and chocolate.

The purpose of work: make skills and attainments of identification of various kinds of chocolate and definition of quality of cocoa powder and chocolate.

1.1 The task

1. Definition of organoleptic indicator of cocoa powder and chocolate.

2. Definition of cocoa powder grinding degree.

3. Definition of fat’ mass fraction by refractometric method.

4.Draw up report on the work done.

1.2. Theoretical part

To get cocoa powder and chocolate the cocoa beans are cleaned and roasted. Then they go trough a machine which cracks them A current of air removes the shells, leaving the edible pieces of cocoa, called “nibs”.These nibs, containing about 54% fat (cocoa butter), are ground between rollers which free the fat and produce a brown liquor. This liquor is treated in presses which turn it into a hard cake after squeezing out some of the fat. This is next crushed and sifted to produce the familiar brown cocoa powder. In the manufacture of chocolate the roasted nibs are mixed with sugar and roughly ground to a paste.

Laboratory work # 6

The task

1. Define phenol matters in grape.

2. Prepare necessary reagents.

3. Draw up report about the effort

Theoretical part

Phenol compounds have one or more hydroxyl groups, connected with carbons of aromatic line. They assist in grape and wine in terms of monomers, oligomers and polymers. Phenol compounds take active part in oxidation-reduction processes, flowing in wort and wine, interact with proteins and metals, forming hard soluble compounds, inducing haze of wines. They take part in formation of bouquet, taste and color of wines. Content of phenol compounds is in white wine 200-1500 mg/dm³, in red wines 1500-5000 mg/dm³. Under technologic store of phenol matters of grape is implied that their part, which can pass into wort by correct processing of working of grape.

Laboratory work # 7

Technique definition.

5-10g of coarsely cut product pour by 1% spirit of salt (not above 20ml) in mortar, grind until indiscrete mass and carry over into 100ml measuring flask. Wash the mortar and add 2% solution of metaphosphoric acid till mark, leave to stand for 10min and filter at once into dry flask. Then take out three 5-20ml’ samples of filtrate (according to content of ascorbic acid). Add a small crystal of potassium iodide (KJ) and several drops of 1% amylase in two parallel samples and titrate from microburet by 0,001mol/dm³solution of iodic potassium(KJO₃) until violet color.

If you determine ascorbic acid’ content in colored solutions, put the3d flask nearby to compare color. The volume 1ml of 0,001mol/dm³solution of iodic potassium corresponds 0,088ml of ascorbic acid.

Calculation of ascorbic acid’ content (X_a) is carried by formula:

 

X_a= V·T ·V₁·100/ m·V₂, where

V- quantity of 0,001mol/dm³solution of iodic potassium, taken for titration of extract, ml;

T- titre -0,088 mg of ascorbic acid, responding 1 ml of 0,001mol/dm³solution of iodic potassium;

100- correction coefficient of ascorbic acid’ content;

V₂- volume of filtrate of being investigated product, taken for titration, ml;

m-weighed amount of product, g.

 

Test questions

1.What is the formula of ascorbic acid?

2. Why man must ingest considerable quantities of this substance?

3.Why it is necessary to add a small crystal of potassium iodide (KJ)?

Laboratory work #8

Technique definition.

Potato tuber or part of cabbage head grate on grater from nonrusting steel. Ground mass squeeze out through mull, mounted in two layers.

To 1ml of new- succus of potatoes or cabbage add drop wise of methylene blue and 2-3 drops of soda solution. Test tube slightly heat. See after discoloration of blue color.

Technique definition.

1 ml cabbage or potatoes juice pour in test-tube, add 3-4 drops of 2% spirit of salt and dropwise solution of 2,6-dichlophenolindophenol. Reagent will discolor till all ascorbic acid acidify to dehydroascorbic, after which still first drop of solution colors liquid in pink, because 2,6-dichlophenolindophenol any more restores.

3. Reaction with potassium ferricyanide. Ascorbic acid, when acidify, reduces potassium ferricyanide K₄Fe(CN)₆ to ferrocyanide K₄Fe(CN)₆, which with ion ferric forms in acidic medium ferric ferrocyanide Fe4[Fe(CN)₆]₃.

Reagent and facility: cabbage or potatoes juice; test tube; dropping-bottle; potassium ferricyanide, 5% sol.; potassium hydroxide, 5%sol.; salt acid,10%sol.; ferrichloride, 1%sol.

Technique definition.

To 1 ml cabbage or potatoes juice add 2 drops of caustic potash solution, just as much solution of potassium ferricyanide and shake test tube, whereupon add drop wise 10% spirit of salt and 1-2 drops of solution ferrichloride. Dark blue or greenish-dark blue sediment of ferric ferrocyanide separate out, which show that there is ascorbic acid.

 

Test questions

1. What are reducing properties of ascorbic acid.?
2. By what elements does ascorbic acid in the light reduce?

Laboratory job №9

Theme: Definition of fats mass share in cans by refractometric method and total acidity in canned goods with sour fillings

The purpose of work: Definition of refraction coefficient of fat solution in solvent- naphthalene monobromate, by which fats are pulled out preliminary from researched product and experimental definition of total acidity in canned goods with sour fillings.

1.1 The task

1. Definition of fat’ mass fraction by refractometric method.

To make skills and attainments of definition by refractometric method.

2. Definition of total acidity in canned goods with sour fillings

3. Draw up report on the work done.

1.2. Theoretical part

Method is founded on pulling out fat from sample with the help of naphthalene monobromate and definition refraction index of solvent and solution of fat in solvent with the help of refractometer. Naphthalene monobromate well dissolves fat in the cold and have high rate of refraction, differ markedly from from refraction index of fat. On dissolving of fat by naphthalene monobromate refraction index decrease at amount, proportional amount of fat resolve.

In canned goods with sour fillings total acidity is normed. So, acidity in recalculation on an apple acid must be from 0,3 up to 0,6 %.

Rules of safety measures

On first practicum student must be acquainted with safety arrangements and running regime. In service in laboratory it is necessary to carry out follow:

- put on dressing grown

- control, all of necessary items are in place

- during runtime practicum it needs to observe silence

- avoid excessive walking, opening and closing of door

- in laboratory no smoke or meal

- shouldn't take out outside of chair, some kinds of materials (test-tubes, reagents)

- individual things it is necessary to head up assigned for that place

 

Every laboratory work takes shape in the form of report with short description of theoretic information, method of procedure, experimental results and conclusion. At the end of lessons student must set in order desk top, rub and take away apparatus, carefully wash hands and lay off dressing grown.

 

Literature

1. Донченко Л.В., Надыкта В.Д. Безопасность пищевой продукции. Москва. ДеЛи принт, 2007 г.

2. Поздняковский В.М. Гигиенические основы питания. Качество и безопасность пищевых продуктов. Сибирское университетское издательство. Новосибирск,2007

3. Срок годности пищевых продуктов. Расчет и испытание. Под редакцией Р.Стеле. Санкт- Петербург. Профессия,2008

4 Павлоцкая Л.Ф. и др. Пищевая, биологическая ценность и безопасность сырья и продуктов его переработки. Киев,2007

5 Гигиенические требования к качеству и безопасности продовольственного сырья и пищевых продуктов. Москва. Госкомсанэпиднадзор России. 1997 г.

6. Позняковский В.М. Гигиенические основы питания, безопасность и экспертиза продовольственных товаров. Новосибирск. 1999 г.

7. Руководство по методам анализа качества и безопасности пищевых продуктов. Скурихин И.М. Тутельян В.А. Москва, 1998 г.

8. СТ РК 30-94 Государственная система сертификации Республики Казахстан. Основные положения

9. СТ РК 3.15.2-98 Государственная система сертификации Республики Казахстан. Сертификация система качеств.

 

 

КАНТУРЕЕВА ГУЛЬЖАН ОРЫНБАСАРОВНА

 

УРАЗБАЕВА КЛАРА АБДРАЗАКОВНА

 

 

 

Методические указания к выполнению лабораторных работ по дисциплине «Безопасность продукции перерабатывающих производств» для студентов специальности 050728-«Технология продукции перерабатывающих производств».

 

 

Подписано в печать. Формат бумаги 60х84 1/16.

Бумага типографская. Печать офсетная. Объем п.л.

Тираж 100 экз. Заказ №

 

 

Издательский центр ЮКГУ им. М.Ауезова

г. Шымкент, проспект Тауке хана,5

 

The content

Introduction………………………………………………………………………………………...6

Laboratory work # 1 Definition of oxidation of dairy butter. ……………………………………..7

Laboratory work # 2 Quality assessment of bread and bakery products.………………………….9

Laboratory work # 3.Definition of physicochemical

parameters of sugar-beet. …………………………………………………………………………10

Laboratory work # 4. Research of assortment and estimation

of mayonnaise quality.……………………………………………………………………………..14

Laboratory work # 5.Quality determination of cocoa powder

аnd chocolate……………………………………………………………………………………....16

Laboratory work # 6 Definition of phenol compounds

in vegetable products.……………………………………………………………………………...19

Laboratory work # 7.Definition of content of ascorbic acid

by iodimetric method……………………………………………..………. ………………………21

Laboratory work # 8. Analysis of reducing properties

of ascorbic acid…………………………………………….……………………………………….24

Laboratory work # 9.Definition of fats mass share in cans by refractometric method

and total acidity in canned goods with sour fillings…………….……...……………………….26

Laboratory work # 10.Definition of calcium content in food products….……………………......30

Rules of safety measures…………………………………………………………………………...38

Literature…………...………………………………………………………………………………39

 

Introduction

In consequence of systematic study of discipline «Processing productions safety» students solve following objectives: safety of food products and their production from the point of view of health and reliability for the people and environment, estimation methods and safety criteria for food production, microbiological safety quotient of food production, risk of disadvantage or superfluity nutrient materials, danger of xenobiotics from ambient medium, main criterion of safety food additive, mainstream industry article development of food in ХХI century, definition methods of content toxic elements in food products.

Laboratory workshops are connected with theory. On practicum students fortify obtained theoretical skills, get hand-on experience by definition of process specifications of preparation and delivery of ready-to-eat meal in accordance with applicable standards, norms and other scientific and technical documentation.

It is essential that students learn to economize chemical reagents, carefully refer to laboratory apparatus and facility, and follow regulations of personal hygiene and prophylaxis, safety procedures.

 

Laboratory work #1

Definition of butter fat oxidation level.

Purpose of the work: experimental determination of butter fat oxidation level

1.1. The task

1. Define oxidation level of dairy butter.

2. Calculate real optical density by formula.

3. Draw up report about the effort.

Theoretic part

Method is founded on formation of colored compounds of 2-thiobarbituric acid with some of secondary products of oxidation fat. Color grade depend upon oxidation rate of fat, as a result of which aldehydes form. Main of last is molon aldehyde. In absorption spectra of colored compounds there are two maximums, where the first (450 nm) corresponds yellow colored condensate of 2- thiobarbituric acid with monoaldehydes, but the second (535 nm) - red colored union 2- thiobarbituric acid with dialdehydes.

The given reaction is widely used for degree evaluation of vegetable and animal fats oxidation, owing to high sensitivity, reproducibility and correlation of this index with organoleptic estimation of fat freshness. Due to the fact that mechanism of this reaction is unknown fully, analysis results are expressed by per unit of absorbance. Analysis of fat oxidation degree of various products with 2-thiobarbituric acid differs by distinction of sample preparation for measurement of absorbance by spectophotometer Especially it concerns the method for discriminating of fat.

Technique definition.

Chemical reagents: 1n spirit of salt; petroleum ether; reagent of 2-thiobarbituric acid; extraction mixture (isoamyl alcohol and 99% pyridine in balance of volumes 1:1).

Weighed portion of dairy butter (10g) is settled in centrifugal test-tube with stoppered and is hold in hot water with temperature 70-80 gr C during 3 min for complete fusion of milk fat. Next 2 ml of distil water,1 ml of 1n spirit of salt are added in test-tube, then it is shacked up strenuously, reheated 1 min and centrifugated 3 min (about 5000 rounds per min). Layer of milk fat is pipetted off. Water fraction is cleaned by several portions of petroleum-ether until disappearance of visible slosh. The ether every time is deleted by pipette with pumping out rubber bulb. In the end of flushing out contents test tube is centrifugated 2-3 min for more complete dissection of ether. 1,5 ml reagent of 2-thiobarbituric acid adds in caught-on of water fraction and then it is hold on boiling-water bath 15 min. Test tube is quenched to 18-20 gr C,

5 ml extraction mixture is added, then strenuously shaken and centrifugated 10 min by 5000 rounds per minute.

Clear color solution is carried over by pipette in cuvette 1cm,then optical density is measured under λ =490Nm, 535 Nm and 580 Nm. Control experiment is prepared in simulated conditions, but without butter, and 3,6 ml water instead 2 ml is added taking into account humidity of dairy butter.

Calculation of real optical density of colored compounds is carried by formula:

D=D535- D490+ D580,

where D535 - maximum absorption of colored compounds under λ =535Nm,

D490 и D580 - minimal absorption in spectrum of determined colored compounds under λ =490Nm, 580 Nm, their optical density is minused for liberation from phone.

A report on task performance.

Student designs activity report. Accounting results are filled in table1.

 

Product under investigation	Optical density λ= (nm), where
Dairy butter	Д535	Д490	Д580	Д

 

 

Quiz:

1. Wherein does oxidation level of dairy butter consist?.

2. By what formula do you calculate real optical density of colored compounds?

3. By what does analysis of fat oxidation degree of various products with 2-thiobarbituric acid differ?

4. Why weighed portion of dairy butter is hold in hot water with temperature 70-80 gr C?

Laboratory work #2

Theme: an estimation of quality of bread and bakery products

The purpose of job: To carry out an estimation of quality of the offered samples of bread and bakery products by organoleptical, physical and chemical parameters.

1.1. The task

1. Define an estimation of quality of bread and bakery products.

2. Learning of bakery products defects.

3. Draw up report about the effort

Theoretic part.

Potato bacillus, molding of bread and other diseases, called by wrong keeping and processing of charge stock, can induce diseases of man. In aid of food safety in the manufacture of bread it is necessary to use quality products, passed off microbiological and physicochemical check-out. End products also must compliant with standards.