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Dnepropetrovsk National University OlesyaGonchara

Biological Sciences / Microbiology

Assessment of the quality of bakery products

Vysotina I.B.,

Voronkova O.S.,

Vinnikov A.I.

Introduction

The raw materials for the manufacture of bread and bakery products are flour, fats, sugar, milk and other products. All of them contain a rich and diverse microflora, which is introduced as a leaven into the dough. In addition, most bread production lines have an open system that is vulnerable to contamination by various types of microorganisms. Therefore, in a fermenting dough or sourdough, in addition to Saccharomyces yeast and lactic acid bacteria, extraneous microorganisms are usually found. The latter can significantly affect the quality of the manufactured product, causing its deterioration at various stages of the production process.

Conventionally, microorganisms - contaminants are divided into 3 groups: saprophytes, the presence of which does not affect the fermentation process; microbes that disrupt the normal course of fermentation and degrade the quality of the finished bread; production pests that cause spoilage of bread.

The first group includes, for example, micrococci. The source of their entry into semi-finished products is flour. Micrococci quite often appear in small quantities in the dough, without making a noticeable impact on its quality. Microorganisms that are undesirable in the dough include "wild" yeast, as well as some types of bacteria, such as B. coagulans (L. thermophilum) and L. mesenteroides. They can be attributed to the second group. The third group includes pathogens of potato disease, mold, as well as cretaceous disease and redness of the crumb.

The aim of the work was to consider methods for assessing the quality of bread products.

Organoleptic analysis of bread quality

The quality of bread is primarily evaluated organoleptically. Organoleptic (sensory) analysis includes an assessment of taste, smell, texture, structure, color, shape, size, appearance and surface condition of the finished product. This analysis is performed using sight, smell and taste and therefore does not require any special equipment or expensive reagents. The main disadvantage of sensory analysis is the low level of information content and the impossibility of obtaining all the information. A product that fully meets all the requirements in terms of its organoleptic characteristics cannot, on this basis, be recognized not only as fully possessing its nutritional value, but simply as safe for health.

The organoleptic assessment of the state of the product is of a qualitative nature, while the final conclusion about its safety for the health of the consumer or nutritional value today requires the involvement of quantitative indicators. The shape of the products must correspond to their name, be not vague, without lateral influxes.

The surface is smooth, without cracks, the color of the crusts is uniform, not pale and not burnt. The thickness of the peel is 3-4 mm. The smell is pleasant, characteristic of this variety, homogeneous, without impurity (foreign) odors.

The taste, also inherent in this variety, without yeast and other foreign flavors, not bland, not too sour and not oversalted. With obvious and numerous violations of organoleptic properties, bread at this stage of control can be recognized as unfit for consumption and rejected. The combination of a large number of indicators determined by organoleptic, bacteriological and mainly physicochemical methods allows us to draw a conclusion about the nutritional value and safety of the tested products, which in fact are the two main criteria for the quality of any food product.

Nutritional value is understood as a set of properties of a product that determines its ability to satisfy the physiological needs of the body for nutrients and energy. Bakery products are a rich source of carbohydrates and proteins. The energy value of any food product is an indicator that determines the amount of energy that is released as a result of biological oxidation in the body of chemical compounds that make up this product.

Laboratory analysis of the quality of bread products

Compliance of a batch of bread and bakery products with the requirements of a standard or technical specifications by external signs is determined selectively, by examining all the bread on 2-3 trays of each rack, and when storing bread on the shelves, 10% of the products from each shelf are selected.

An average sample is taken from every 10 trays or 10 boxes in the following quantities: with an individual product weighing from 1 to 3 kg - 0.2% of the entire batch, but not less than 5 pieces; with a product weight of less than 1 kg - 0.3% of the entire batch, but not less than 10 pcs.

From the average sample, typical products are taken as laboratory samples in the following quantities: weight and piece products weighing more than 400 g - 1 pc.; piece weighing from 200 to 400g - at least 2 pieces; piece weighing from 100 to 200g - at least 3 pieces; piece weighing less than 100g - 6 pcs.

Before analyzing the quality of finished products, it is necessary to prepare samples. Samples consisting of a whole product (by weight, piece weighing more than 500 g) are cut in half in width and a piece (chunk) weighing about 70 g is cut from one half, from which the crusts and subcrustal layer are cut off with a total thickness of about 1 cm. On a sample consisting of a part of the product, a continuous cut about 0.5 cm thick is made from the windward side. Sampling and preparation for analysis are carried out in accordance with GOST 5667-65, 5, 8-10.

The determination of moisture, which is an important indicator of the quality of bread, is carried out in accordance with GOST 21094-95. High humidity reduces the calorie content and worsens the quality of bread. It becomes heavier, worse absorbed by the body. Such bread is more likely to be moldy, disease, and easily deformed. The low humidity of bread leads to the fact that it becomes dry, quickly stale, its taste worsens. Humidity is set by the standards at a certain, optimal level for a given product, depends on the strength of the flour and the bread recipe, and to a certain extent is related to nutritional value, since the proportion of nutrients decreases with increasing humidity. The moisture content of bread is expressed (in %).

Determination of acidity (GOST 5670-96), which to some extent characterizes the taste of bread, is also one of the indicators of laboratory research. Not enough or too sour bread tastes bad. The acidity of bread (like flour) is expressed in Neumann degrees (°H).

Porosity is understood as the ratio of the volume occupied by the pores of the crumb, expressed as a percentage, to the total volume of the crumb. Porosity is determined in bread (GOST 5669-96), as well as bakery and fancy products with a mass of 0.2 kg or more. Its digestibility is related to the porosity of bread. Well loosened bread with a uniform fine thin-walled porosity is easily chewed and soaked in digestive juices and therefore more fully absorbed.

When buying bread, as a rule, attention is paid to its external features and consumers themselves evaluate the quality of bread, however, before selling, a thorough laboratory analysis of the products is necessary, since it is impossible for the consumer to establish the presence or absence of chemical agents, contamination by microorganisms, etc. P. factors. The consumer can evaluate only such external characteristics as the volume of bread, the elasticity and porosity of the crumb, the color of the crust and appearance, aroma and taste.

Bacteriological control

Another way to determine the quality of bread is bacteriological control. Under production conditions, it consists of two processes: in one case, the contamination of raw materials is monitored, in the second case, the contamination of finished products is examined.

When purchasing raw materials (flour, starter cultures of fermenters), they are checked for the presence of microorganisms - contaminants. The presence of mold fungi and bacilli in the raw material is determined. In the presence of the latter, their type and degree of contamination are determined, after which a conclusion is made about the suitability / unsuitability of the raw material for use.

Flour contamination is usually caused by "wild" yeast. This is a group of microorganisms, which in baking is understood as representatives of the genera Candida, Torulopsis, Pichia. Most often in semi-finished bakery products there are three types of the genus Candida - C. krusei, C. mysoderma and C. utilis. Two more types of yeast-like fungi are involved in spoiling bread - Endomycopsis fibuliger and Endomyces chodacii. With their development, white, dry, powdery spots similar to chalk form on the surface of the crust and in the crumb. This defect in bread is called chalk disease.

In addition, spoilage of bread is possible when the sourdough is contaminated. Before introducing the culture of fermenters, the purity of the starter is checked. Normally, it should contain industrial yeast - Saccharomyces spp.. and lactic acid bacteria of the genus Lactobacillus spp.. Technically harmful microorganisms also include some thermophilic rod-shaped bacteria, for example B. coagulans, also known as Lactobacterium thermophilum. According to the draft International Code of Nomenclature for Bacteria, this species is excluded from the genus Lactic acid bacilli and is considered as an asporogenic variant of thermophilic spore bacteria.

Among bacteria, the pathogens of the potato, or viscous, bread disease, well-known in the baking industry, play the greatest role - AT. mesentericus and B. subtilis, which withstand the temperature of baking bread well and can lead to further spoilage of the product. Also, but much less often, representatives of the genus Propionibacterium and type Chromobacterium prodigiosum, which cause souring of bread and pronounced deterioration of its organoleptic properties.

Bread is sold in the store for three days. During this time, the development of mold fungi and potato sticks is possible. In parallel with the sale of products, monitor how the bread becomes stale and moldy, for which a control batch of bread is left in the laboratory of the enterprise. Normal bread should begin to dry out the very next day after being made.

On the third day, it should be cracker with no signs of mold. If the bread, being in a plastic bag, is moldy, then the mold should be either white or green. And by no means black. Unlike bacteria, mold fungi are a secondary infection that infects already finished products. Mold spores found in flour are usually killed during baking. Bread comes out of the oven almost sterile. During cooling, transportation and storage, the surface of the bread is re-contaminated with mold spores. Bread becomes infected by direct contact with contaminated items (transport and packaging equipment, hands and clothing of personnel) or through the air. At the same time, the degree of contamination of bread reflects the general sanitary condition of the plant. Moldy bread should not be eaten.

Of particular danger is the development of fungi from the genus Fusarium. They usually infect grain that has overwintered in the field, or late varieties of wheat and rye. The toxic substances emitted by this mold are not destroyed during the baking of bread. Infected bread does not have external signs of the disease, but when it is consumed, acute poisoning occurs, often with a fatal outcome.

The control of products for the presence of unsafe microorganisms is carried out both by the laboratory of the enterprise and by the control laboratories of the sanitary and epidemiological service and metrological laboratories. The analysis primarily includes inspection of bakery products to identify deviations in their appearance, at the second stage, microscopic control of suspicious objects is carried out, and bacteriological analysis is carried out, if necessary, only in specialized laboratories, as a rule, outside the manufacturer's enterprise.

quality bakery flour organoleptic

Conclusion

It can be concluded that, in general, spoilage of bread products occurs after the completion of the production process, when the heat-treated bread again becomes available for contamination. To avoid contamination of bread at the enterprises, a set of measures has been developed. The main protective measures at bakeries to reduce the contamination of bread are air purification, immediate removal of moldy bread from the shops, keeping equipment and raw materials in perfect cleanliness and observing the rules of personal hygiene of the personnel.

The air in the room is purified by filtration or ozonation. Good results have been obtained with germicidal lamps. Premises and equipment are treated with bactericidal and fungicidal agents. In addition, it is recommended that the interior coating of bread vans, as well as trays, be made of plastic and periodically disinfected with a 2-3% solution of acetic acid.

Microbiological spoilage of bread causes serious damage to the industry. The variety of methods and techniques proposed to combat the main causative agents of bread disease indicates the absence of a single radical remedy. To prevent the development of bread diseases, it is necessary to apply a whole range of measures. Properly organized microbiological control of bakery production plays an important role in this.

Literature

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The paper presents an analysis of the theoretical material on the issue of bread quality, reflects the practical (experimental) part with the corresponding conclusions

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Introduction

Bread and bakery products have an exceptional place in human nutrition. Bread is never boring and contains almost all the necessary components: proteins, carbohydrates, some fats, vitamins and minerals.

A person chooses bread based on taste, appearance, packaging, and only a small part of the population pays attention to the composition of the product. Accordingly, the composition of the product should reflect its quality, based on the above, we put forward a hypothesis: do the quality indicators of bread meet the requirements of GOST.

Objective - to identify whether the physical and chemical indicators of the quality of bread meet the requirements of GOST.

Object of study -physical and chemical indicators of bread quality

Subject of study -porosity, acidity and moisture content of bread.

To achieve this goal, the following tasks:

1. study the information base on this topic;
2. identify the most preferred by residents with. Meadow varieties of bread;
3. master research methods;

1. Determine the porosity of bread (according to GOST 5669-96 "Baked products. Method for determining porosity")
2. Determine the acidity of bread (according to GOST 5670-96 "Baked products. Methods for determining acidity")
3. Determine the moisture content of bread by drying to constant weight.

Research methods:

1. Questionnaire
2. chemical experiment

1. A bit of history and the benefits of bread.

Bread is the ambassador of peace and friendship between peoples, and remains so today. Life is changing, values ​​are being reassessed, but bread-father, bread-breadwinner remains the greatest value. They escorted them to the front with bread, met those who returned from the war, commemorated those who would never return. Everyone has their own bread. Everyone remembers, perceives and appreciates it in their own way.

It is necessary to speak and write about bread, about the attitude towards it, so that our children do not grow up ignorant, so that for them, as well as for us, fathers and mothers, with the words Motherland, Friendship, Peace, Father, Mother, the word Bread stands nearby. Love and respect for bread must be taught from childhood, this love must be instilled in the family, in kindergarten, and at school.

For a long time, people ate raw grains, then they learned to grind them between stones, getting cereals, and cook it. So the first millstones, the first flour, the first bread appeared.

The first bread looked like liquid porridge. She is the mother of bread. It is still used in our time in the form of bread stew in some countries of Africa and Asia.

By chance, a man discovered that if overheated grains, that is, fried ones, are crushed and mixed with water, the porridge turns out to be much tastier than the one he ate from raw grains. This was the second discovery of bread.

Archaeologists suggest that once during the preparation of grain porridge, part of it spilled out and turned into a ruddy cake. With her pleasant smell, appetizing appearance and taste, she surprised a person. It was then that our distant ancestors began to bake unleavened bread in the form of flat cakes from thick grain porridge. The dense, unleavened, burnt pieces of the brown mass bore little resemblance to modern bread, but it was from that time that bread baking arose on earth.

Breakfast is a boost of energy, a vitamin boost, the necessary energy, breakfast is a must. The wrong breakfast affects the emotional mood: if 2-3 hours after waking up your mood deteriorates, it means that you ate something wrong or didn’t eat anything. Everyone has seen what a classic American or English breakfast looks like: dried bread with a thin layer of butter and a glass of freshly squeezed orange juice. This breakfast is the perfect start to the day, a full charge of B vitamins. Vitamin B is the most tricky, if there is not enough of it in the body, you will more and more fall into apathy and lethargy, besides, B vitamins also support other vitamins, without them the entire vitamin range will fall into decay.So, in the morning we eat bread, and dried bread is easier to digest, plus butter, plus orange juice, and the daily intake of vitamin B is in your pocket.

Bread is white and black (rye). White bread is baked from refined flour, in the process of its manufacture, shells and germs (bran) are separated from the grains, so white bread is stored longer (bran quickly oxidizes and spoils the flour) and has a more uniform taste. It is believed that it is less useful than rye, because there is very little fiber in it, as well as other valuable substances. For example, iron in rye bread is 4 times more than in white. Another such unappetizing fact is that flour is bleached with bleach. Researchers argue that black bread has a beneficial effect on reproductive function, there was a saying among the people "Eat rye bread - you will not fall asleep with your wife." However, do not exaggerate the value of rye bread, if you have high acidity, gastritis or ulcers - eat white bread or crackers. By the way, eating 500 grams of white bread a day, you provide yourself with a daily intake of calcium by 17%, phosphorus by 61, magnesium by 48 and iron by 70%.

Any bread contains amino acids - builders of proteins. There is very little fat in bread (0.5-1.5%), it mainly consists of carbohydrates. It happens that bread is enriched with additives - seeds, dried fruits, soybeans, all this is very useful, but it is not at all necessary to choose just such bread.

High-quality bread has a clean surface, without coarse cracks, its crust lags behind the crumb. German researchers have found that the bread crust is a rich source of antioxidants and provides many more health benefits than the rest of the bread. Small unleavened buns are especially useful, they are often served in canteens, they have a lot of crust - and it bakes well.

1. Requirements for the quality of bread

The quality of bread and bakery products is determined by organoleptic and physico-chemical parameters in accordance with the requirements of the standards.

To organoleptic indicatorsinclude appearance, condition of the crust and crumb, taste and smell.

Table 1

Characterization of organoleptic indicators of bread quality

Physical and chemical indicators of the quality of bread are determined by laboratory methods and include the determination of crumb moisture, acidity, porosity, fat and sugar content (for products whose recipes include fatty products and sugar), as well as, depending on the type of product, wetting (rusks), swelling (bagel products), content of carbohydrates, sodium chloride, iodine, etc. (diet varieties).

Our study relied on the followingphysical and chemical indicatorsbread quality: moisture, acidity, porosity.

table 2

Characteristics of physical and chemical indicators of bread quality

Bread defects are caused by the quality of raw materials and occur when the bread production technology is violated, as well as when the conditions for transporting and storing bread and bakery products are not observed. ToAppearance defects include:

1. irregular shape of products, which can be when using flour with low gluten quality, with improper molding and insufficient or excessive proofing of the dough;

1. cracks on the surface are formed when baking bread from fermented dough, and small bubbles - when baking from unfermented dough;

1. a dark color or thick crust appears when the temperature or baking time is increased; an increased amount of sugar in the dough causes a dark color of the crust, a reduced amount - pale.

During transportation and storage, bread can be deformed as a result of careless or dense packing of hot products in containers.

Crumb defects occur when using flour made from sprouted grains or when adding too much water, resulting in an undercooked and sticky crumb. Crunchiness is due to insufficient water during kneading; crumbling is also a sign of stale bread. The lack of crumb crumb - the presence of lumps of flour, lobe (old bread) - is caused by insufficient kneading of the dough. The presence of hardening in bread is not allowed. Temper is a layer of compacted, non-porous, sticky crumb, usually near the bottom crust. During storage, hardening may occur when stacking hot products in multiple rows.

Taste and odor defectscan be when using flour that has been stored for a long time or made from defective grain. Fermented bread tastes sour, while unfermented bread tastes unleavened. Oversalted, undersalted taste is caused by the wrong dosage of salt. The presence of a crunch on the teeth when chewing bread can be caused by the ingress of mineral impurities into the flour; such bread is not allowed to be sold. During storage, the bread acquires the specific aroma and taste of stale bread.

Chapter II. Analysis of physical and chemical indicators of bread quality

The analysis of physical and chemical indicators of the quality of bread was carried out based on the results of the survey proposed in Annex 1.

According to the results of the survey, we have identified 3 varieties of bread most commonly eaten by the population of the village of Lugovoe, Tavrichesky municipal district: wheat bread produced by Complex Tavrichesky LLC(1*) , wheat bread produced in Novouralskoye village(2*) , wheat bread produced by Sibkhleb(3*).

The analysis procedure was carried out in accordance with the requirements of GOST.

1) Bread moisture

The moisture content of bread is determined to calculate its energy value, product yield and to check the correct dosage of the main raw materials - flour and water. The higher the moisture content of bread, the lower its energy value. With an increase in the moisture content of bread by 1%, its yield increases by 2-3%. To determine the moisture content of bread, an accelerated standard method is used, according to which a sample of bread crumb is dried to a constant weight. Humidity of wheat bread is on average 40-45%

Definition progress.

A piece weighing about 70 g is cut out from the middle of the bakery product, the crusts and subcrust layer about 1 cm thick are cut off from it. The crumb is quickly crushed with a knife and mixed. Two portions of 5 g each, weighed to the nearest 0.01 g, are placed in pre-weighed weighing bottles (or chemical beakers) and transferred to an oven heated to a temperature of 140-145°C, where they are dried for 50 minutes at a temperature of 130 ± 2°C. After the time has elapsed, the bottles are removed, covered with lids and cooled in a desiccator (or in air) for 10-15 minutes. Then the weighing bottles are weighed and the moisture content of the bread is calculated as a percentage:

ω (H 2 O) \u003d 100 (m-m 1) / m
where m is the mass of raw crumb; m 1 is the mass of dry matter of bread.

The final result is expressed as the arithmetic mean of the two determinations. The results obtained are presented in Table 3.

Table 3

Bread Moisture Determination

Conclusion : During the experiment, the humidity turned out to be higher in the variety of bread produced with. Novouralskoye, which meets the requirements of GOST. Humidity of bread varieties 1*, 3* is low.

2) Porosity of bread

Under the porosity of bread understand the volume of pores in a given volume of the crumb, expressed as a percentage. Porosity (P) is calculated by the formula:

П=100 (V–V 1 )/V
where V is the volume of the cut crumb; V 1 - the volume of non-porous crumb, compressed to failure.

Porosity characterizes an important property of bread - its greater or lesser performance. Low porosity is usually inherent in bread made from poorly attenuated dough. The porosity of wheat bread is 55-70%, depending on the type of bread and the way it is baked. We carry out the determination of porosity according to a simplified method.

Definition progress.

A crumb cube with a rib length of 3 cm is cut out from the middle of the product, which corresponds to a recess volume of 27 cm 3 (V). This cube is divided into several parts, squeezed with fingers until the pores are completely removed and dense balls with a diameter of not more than 1 cm are made from them. The balls are lowered into a measuring cylinder with divisions of 0.5 or 1 ml, filled to a certain level with kerosene or oil. The volume of bread without pores (V1) is determined from the difference in the liquid level in the cylinder and its porosity is calculated.

For wheat bread, three notches are made and the average value of porosity is found.

Table 4

Porosity of bread

Conclusion : According to experimental indicators, the porosity of all considered varieties of bread and long loaves is from 70% to 82%, which corresponds to medium and high rates and indicates a well-fermented dough.

3) Acidity of bread

The acidity of bread is expressed in degrees of acidity, which is understood as the number of milliliters of 0.1 N. an alkali solution necessary to neutralize acids in 100 g of bread. For wheat bread, acidity is not more than 7-9 0 .

Definition progress

To determine the acidity, small pieces are cut out of the crumb of bread and weighed on a technochemical scale with an accuracy of 0.01 g, a sample of 25 g. distilled water heated to 60°C. First, about 1/4 of the water taken is poured into a flask with bread and the crumb is rubbed with a spatula to obtain a homogeneous mass, and then the remaining water is added, the flask is closed with a cork and shaken vigorously for 2-3 minutes. The mixture is left to stand at room temperature for 1 min, after which the liquid layer is poured into a dry flask through two layers of gauze. Subsequently, 50 ml of the settled liquid (without sediment) is taken into two flasks with a pipette, 2-3 drops of a 1% alcohol solution of phenolphthalein are added and titrated from a burette with 0.1 N. sodium hydroxide solution until a faint pink color appears, which does not disappear within a minute. The acidity of bread is calculated by the formula

X = a V 100 / p 10

where X is acidity in degrees; a - the amount of ml 0.1 n. alkali used for titration V ml of extract; v is the volume of the extract taken for titration, ml; V is the total volume of the extract, ml; p is the mass of a sample of bread, g.

The results are presented in Table 5.

Table 5

Determination of the acidity of bread

Conclusion. Bread produced by Complex Tavrichesky LLC exceeds the acidity readings according to GOST, the acidity of others is within the normal range.

Findings:

1. We studied the chemical and scientific literature on the quality of bread and bakery products, identified the physical and chemical indicators of the quality of bread: porosity, acidity and moisture.

1. We analyzed the physical and chemical indicators of the quality of bread, revealed that not all products meet the requirements of GOST, therefore, the cooking recipe is not fully observed, the storage and transportation conditions of the goods may have been violated.

Literature

1. GOST 5667-65. Bread and bakery products. Acceptance rules, sampling methods, methods for determining organoleptic indicators and product mass.
2. Barabanova, E. N. et al. Handbook of a food merchandiser. - Moscow.: Economics, 2004.
3. Borovikova L.A. Research of food products. 2005
4. Goroshchenko, L. Bread and bakery products // Food business. - 2006. - No. 8.
5. Chemistry at school, 2009, No. 5-80.
6. http://www.russbread.ru.
7. http://www.bread.tj/
8. http://festival.1september.ru

Introduction…………………………………………………………………….…2

Chapter I. The role of bread in human life

1. A bit of history and the benefits of bread………………………………….3
2. Requirements for the quality of bread………………………………………...………………………………………………………………………………………………………………………………………………

Chapter II Analysis of physical and chemical indicators of the quality of bread………………………………………………………………………......10

Conclusions………………………………………………………………..……....15

Literature………………………………………………….…..…………….16

Bread research

Purpose of the lesson:
Master the methods of sanitary examination of bakery products

Tasks:

1. Familiarize yourself with the methods of sampling bread for research.

2. Give an organoleptic evaluation of the proposed bread samples.

3. Determine the porosity in the bread.

4. Answer security questions and solve problems.

Sample selection:
Samples are taken from a batch of bread and bakery products that meet the requirements of the standard or specifications.
Batch is considered to be bread and bakery products of the same name, manufactured by one enterprise and received according to one invoice. The average sample is considered to be a part of the batch, appropriately selected, the external features of which characterize the entire batch.
The average sample is taken in the following quantities: with a mass of 1 to 3 kg - 0.2% of the entire batch, but not less than 5 pieces; with a mass of less than 1 kg - 0.3% of the entire batch, but not less than 10 pieces.
Bread is taken from the average sample for laboratory research in the following quantities: from weight and piece products weighing more than 400 g - 1 piece; weighing from 400 to 200 g - at least 2 pieces; weighing from 200 to 100 g - at least 3 pieces; weighing less than 100 g - at least 6 pieces.
Laboratory samples are packed in paper, tied with twine, sealed, a selection certificate is applied, which indicates: 1) product name; 2) date and place of selection; 3) weight and batch number; 4) date and hour of batch baking; 5) who made the selection, the name of the enterprise that manufactured the product; 6) the purpose of the study.

Organoleptic evaluation of bread.

According to organoleptic indicators, bread must meet the following requirements: Surface - smooth, without large cracks and undermining, rolls and loaves with cuts, for round rolls, pins are allowed.
Large cracks are cracks that pass through the entire upper crust in one or more directions and have a width of more than 1 cm.
Large breaks are considered to be breaks that cover the entire length of the side of the pan bread or more than half the circumference of the hearth bread and have a width of more than 2 cm for a hearth bread and more than 1 cm for a pan bread; Coloring : for wheat bread from light yellow to brown, without burntness and pallor, for rye bread - uniform, from light brown without burntness and pallor; state of the crumb characterized by: baked (should not be sticky, mixed, without lumps); porosity (do not have voids and signs of hardening); elasticity (when gently pressed with fingers, it should take its original shape); freshness (not being stale); taste and smell characteristic of bread (lack of sour, insipid taste, bitterness, musty smell).

physical and chemical indicatorsdetermine, counting from the moment the products leave the oven, not earlier than 3 hours and not later: for bread from wholemeal flour - 48 hours; for wheat bread from high-quality flour - 24 hours; for small-piece products no earlier than 1 a.m. and no later than 4 p.m.
Physical and chemical indicators of different types of bread:

Determination of the porosity of bread:

For determination, Zhuravlev's device is used, consisting of a metal cylinder (a) with a pointed edge on one side; wooden sleeve (b); a wooden or metal tray with a transverse wall (c). On the tray, at a distance of 3.8 cm from the wall, there is a slot 1.5 cm deep.

Definition progress:
A piece (chunk) with a width of at least 7–8 cm is cut out from the middle of the product. Notches are made from the crumb of the piece at a distance of at least 1 cm from the crusts with the cylinder of the device. The sharp edge of the cylinder is pre-lubricated with vegetable oil. The cylinder is introduced with a rotational movement into the crumb of the piece.

The cylinder filled with the crumb is placed on the tray so that its rim fits snugly into the slot on the tray. Then the bread crumb is pushed out of the cylinder with a wooden sleeve about 1 cm and cut off at the edge of the cylinder with a sharp knife.

The cut piece of crumb is removed. The crumb remaining in the cylinder is pushed out with a sleeve to the wall of the tray and also cut off at the edge of the cylinder.

The volume of the cut cylinder of bread crumb is calculated by the formula:

where: d is the inner diameter of the cylinder, cm; H is the length of the bread crumb cylinder, cm.

With an inner diameter of the cylinder of 3 cm and a distance from the wall of the tray to the slot of 3.8 cm, the volume of the recess of the crumb cylinder is 27 cm 3 .
To determine the porosity of wheat bread, 3 cylindrical recesses are made, for rye bread - 4 recesses, each with a volume of 27 cm 3. The prepared recesses are weighed simultaneously to the nearest 0.01 g.

Porosity is determined by the formula:

where: V - the abundance of the volume of recesses of bread, cm 3; G - mass of recesses, g; p is the density of the non-porous mass of the crumb.

The density of the pore-free mass is taken for bread: rye, wheat-rye and wheat from wholemeal flour - 1.21; rye custard varieties and pecked - 1.27; wheat first grade - 1.31; wheat of the second grade - 1.26.
Porosity is calculated with an accuracy of 1%.

Evaluation of the quality of bread.

Depending on the type of flour, bread is rye, rye-wheat and wheat.

According to the dough recipe, bread is divided into simple, improved and rich.

According to the method of baking, bread is hearth and molded.

Bread is sold by the piece and by weight.

There is no single principle in the name of bread. Often bread is named after the type and grade of flour, sometimes the specifics of the recipe, national characteristics, shape of products, etc. are emphasized in the name.

The quality of bread is determined by the combination of the following properties: energy capacity, biological usefulness, composition, digestibility, food safety, appearance, texture, taste and aroma. When bread is produced according to one recipe from the same type of flour, energy capacity, biological usefulness, food safety are relatively stable indicators, while the appearance, crumb properties, taste and aroma vary significantly depending on the technological regime, conditions and terms. bread storage.

Bread and bakery products are accepted in batches. In the distribution network, bread and bakery products of the same name, received according to one consignment note, are considered a batch.

Quality indicator, appearance, which is characterized by shape, surface and color, is controlled by inspection of all bread or bakery products on 2 ... 3 trays from each container or rack; inspection of 10% of the products of each shelf.

The results of the control are extended to the container, rack, shelf from which the products were taken. Upon receipt of unsatisfactory results, a continuous control (sorting) is carried out.

To control the state of the crumb, taste and smell, a representative sample is made using the method<россыпью>.

The size of a representative sample is determined as follows. From each container, rack, shelf, every 10 baskets, trays or boxes, separate products are selected in the amount of 0.2% of the entire batch, but not less than 5 pcs. with a mass of an individual product of 1 ... 3 kg; 0.3% of the entire batch, but not less than 10 pieces, with an individual product weighing less than 1 kg. The results of the analysis of a representative sample are extended to the entire lot.

To control the appearance of bread and bakery products, sampling is carried out from a representative sample by the method<вслепую>.

To control the state of the crumb, taste, smell, as well as the presence of foreign inclusions, crunch from mineral impurities, signs of disease and mold, five product units are selected from a representative sample.

The organoleptic assessment of bread is carried out in terms of appearance, crumb state, taste and smell.

The appearance of bread is determined by inspection. At the same time, attention is drawn to the condition of the surface of the bread and its color, the condition of the crust and its thickness, and the correctness of the shape. The results of the inspection are compared with drawings or descriptions in the regulatory and technical documentation.

If deviations are found, then it is indicated what they consist of.

The state of the crumb of bread is determined by the bakedness, mixing, porosity, elasticity, freshness. Cooking is determined by touching the surface of the crumb in the center of the product with your fingertips. For baked products, the crumb is dry, for undercooked products, it is moist, raw and can stick to the fingers. The mix and porosity of the crumb are established by inspection of the crumb surface and comparison with drawings or descriptions in standards. There should be no lumps and traces of unmixed bread in the bread. When characterizing the porosity of bread, attention is paid to the size of the pores (small, medium, large), the uniformity of the distribution of pores of a certain size over the entire space of the cut of the bread crumb (uniform, sufficiently uniform, insufficiently uniform, uneven) and the thickness of the walls of the pores (thin-walled, medium thickness, thick-walled ).

The elasticity of the crumb is determined in two ways: by light pressure (without breaking the pores) with the thumb on the surface of the crumb until it is compacted by 5...10 mm in different places at a distance of at least 2...3 cm from the crust or by briefly squeezing the cut product with both hands .

After the cessation of pressure (squeezing), one observes how quickly and completely the crumb acquires its original state. The crumb, which is pressed in and quickly restored without leaving a trace, is characterized as<очень эластичный>. If the crumb is slightly deformed, then it is estimated as<плотный>or<недостаточно эластичный>.

Table 2.2. Evaluation of the quality of bakery products on a 100 point system

* Weight coefficient. ** Evaluation in points, taking into account the weighting coefficient.

Freshness is determined by the dryness of the surface of the peel, the state of the crumb, smell and taste. In fresh products, the crust is dry, its surface is even, not wrinkled and not cracked. The crumb is uniform in color over the entire surface, elastic, soft, and with strong compression forms a dense, non-porous mass. Taste and smell pronounced.

In stale products, the crust is hard, non-brittle, the surface is wrinkled, cracked, the crumb is rough, with strong compression it does not form a dense, pore-free mass. The crumb layer adjacent to the crust (subcrustal) is darker than the rest of the crumb. The smell and taste are characteristic of stale products.

The smell is determined by 2 ... 3 deep inhalation of air from a large surface, first of the whole, and then immediately cut the product. The smell should be characteristic of this type of product, without mustiness, etc.

When determining the taste, slices of about 6-8 mm thick are cut from five products. A sample (crumb and crust) weighing 1...2 g is chewed for 3...5 s. The taste should be characteristic of this type of bread, without foreign taste and crunch from mineral impurities. To control the quality of bakery products, different

Table 2.3. Scoring scales for quality indicators of various groups of bakery products

personal scales and scoring systems. New types of bakery products, as well as products developed by various enterprises of the industry, are evaluated by tasting councils according to a 30-point system.

The most acceptable for characterizing the consumer qualities of bread is the 100-point system developed by the Moscow Technological Institute of the Food Industry (Table 2.2).

Each bread quality indicator is evaluated on a 5-point scale, each point of which corresponds to verbal definitions (Table 2.3). At the same time, products that have received a score below 3 points for any indicator are considered unsatisfactory! and are not subject to further evaluation.

To take into account the significance of the indicators in the formation of the quality of bread, their weight coefficients are established, the sum of which is 20.

The overall score of the bread quality is found by summing the products of the scores of indicators on a 5-point scale by the corresponding weight coefficients.

According to this system, the maximum possible assessment of the quality of bread will be 100 points.

The 100-point system is easily converted into 30-, 25-, 20-, 5-point and other systems by taking the sum of the weight coefficients as 6, 5, 4, 2, 1, etc., respectively.

The difference in varieties of rye and wheat bread is due to the type (yield) of flour taken for baking it. Depending on the method of baking, bread can be molded, i.e. baked in forms or hearth, baked on baking sheets.

The surface of the bread should be smooth, without large cracks and tears. Large cracks are considered to be more than 1 cm wide, passing through the entire upper crust in one or more directions.

The color of the bread should be uniform, brown-brown with some sheen of the top and side crust in hearth bread and the top crust in pan bread. Burnt crusts are not allowed, as well as their excessive pallor. The transition from the crust to the crumb should be gradual, peeling of the crust from the crumb is not allowed.

The shape of the bread must be correct, not vague, not crumpled, without side sags and other defects. The thickness of the upper crust is allowed no more than 3-4 mm. For hearth bread, the lower crust is no more than 5 mm, for tin bread - no more than 3 mm.

The taste of bread should be moderately sour, not oversalted, without signs of bitterness or foreign taste, without a crunch on the teeth from mineral impurities. The smell of bread should be characteristic of this type and variety without extraneous shades.

The state of the crumb is taken into account by the degree of baking, the intensity and uniformity of kneading dough, porosity and elasticity. The bread should be well baked, not sticky, not moist to the touch, without lumps and traces of unmixed, evenly porous. The presence of voids and hardening is not allowed in the crumb, i.e. dense, watery, non-porous areas, usually located near the bottom crust. The crumb should be sufficiently elastic, not crumbly, not stale. With light pressure with your finger - quickly take the original shape.

Determination of the porosity of bread. Cut out from the crumb 1 cube with a volume of 27 cm 3, with sides of 3 cm (the cut cube is the volume of bread along with air. After that, the cube is divided into several parts (recommended 16), from which dense balls with a diameter of 1 cm are made, squeezing them well until possible dense destruction of the pores and the displacement of air from them.Thus, the volume of bread without air is obtained.

Then the balls prepared from one cube are lowered into a narrow graduated cylinder with divisions up to 0.5 cm, filled to a certain division with vegetable oil. By increasing the level of oil in the vessel, the volume of a compressed cube of bread (without air) is judged. In order to determine the volume of pores occupied by air in a taken cube of bread, the second volume of bread obtained without air is subtracted from the initial volume of bread with air 27 cm 3 and the difference is expressed as a percentage.

Example: Assume that after dipping compressed bread balls made from a 27 cm 3 cube of bread into oil, the oil level in the cylinder rises from the 25th division to the 40th, i.e. for 15 divisions. Therefore, the volume of pores in bread is 27-15=12 cm 3 , therefore the desired bread porosity will be equal to 12 ∙ 100: 27 = 44.4%

The result obtained is compared with the sanitary and hygienic requirements for the porosity of bread:

bread made from wheat flour, premium - 70-72%;

first grade - 65-68%;

second grade - 63-65%;

rye-wheat bread, hearth bread - 47%;

shaped - 50%;

bread made from rye flour, peeled - 49-50%;

seeded - 55-57%

The defeat of bread by mold, potato disease and pigment-forming bacteria. Moldy bread. The crumb is mainly affected by mold. Molding of bread is observed at high humidity and its storage in adverse conditions (in dark, poorly ventilated rooms). The molding process is caused by the development of fungi Penicillium glaucum (green mold), Mycog mucedo (capitate mold), etc.

When molding, the chemical composition of bread changes and substances with an unpleasant odor are formed. Bread affected by mold is not allowed to be used for food purposes.

Potato (viscous) disease. The defeat of bread occurs as a result of the development and vital activity in it of bacteria from the Mecentericum group, which are constantly present on potatoes. The causative agents of potato disease are widespread in the external environment and easily get into flour and dough. They contain heat-resistant spores that can even withstand the temperature of baking bread.

Potato disease mainly affects wheat bread with high humidity and high acidity when stored in cramped, hot, poorly ventilated warehouses, usually in the hot season. Rye bread is not affected by potato disease due to its high acidity. The crumb of the affected bread is a sticky, viscous, dirty-brown mass that emits a specific smell of rotting fruit. This liquefied mass contains water-soluble starch hydrolysis products (dextrin, sugar) and protein breakdown products (peptoses, albumoses, etc.).

Bread infected with potato disease is unfit for human consumption.

The defeat of bread by pigment-forming bacteria manifests itself in the form of mucous bright red spots caused by the vital activity of the pigment-forming microbe B.prodigiosus, known as the miraculous stick, on wheat flour products. The development of bacteria occurs in cramped, humid, hot rooms. Changes in bread are not harmful, however, due to the unusual coloring, such bread is not used for food.

Hygienic examination of canned food . Evaluation of canned food is carried out in accordance with SanPiN 2.3.2.560-96 and GOST 13534-89 "Canned meat"; 50105-92 "Canned food and fish preserves".

Canned food, depending on the method of preservation, is produced as true canned food and as conserves. True canned food is a sterile food product in a hermetically sealed container, sterilized in special autoclaves. Preserves - non-sterile food products (sprats, herring, etc.), filled with marinade or spicy brine and hermetically sealed in jars. There are no product sterility requirements for condoms. They can be stored for a short time and only in the cold.

Canned food can be meat, fish, vegetable, meat and vegetable, fruit. The contents of cans must correspond to the name indicated on the label. Canned food and preserves are available in tin or glass containers.

During the sanitary examination of canned food, the state of the container is established and the quality of the contents of the cans is examined in accordance with the requirements for this type of canned food.

External inspection of cans: note the condition of the label, the content of the inscription on the label, the presence of visible defects in the shape of the can, the violation of tightness, rust spots, the state of the seam, the content of prints on the lid and bottom of the can.

The imprints indicate: 1) the number of production - two digits (up to the ninth digit in front of 0); 2) month of production - two digits (up to the ninth digit in front of 0); 3) year of production - the last two digits; 4) shift number - one digit; 5) assortment number 1-3 digits. For canned food of the highest grade, the letter "B" is added to it; 6) system index - 1-2 letters: A - meat industry, P - fish industry, K - fruit and vegetable farming, U.S. - consumer cooperation, M.S. - Agricultural production, LH - forestry; 7) manufacturer's number - 1-3 digits. The imprint can be given entirely in two lines on the lid or on the lid in two lines with the date of production and shift number and assortment number, and on the bottom with the system index and company number.

131088 or on cover 131088

and on the bottom A 151
Canned food was produced on October 13, 1988 in 1 shift with assortment number 183 by the meat industry enterprise № 151.

During an external examination of the cans, attention is paid to the condition of the bottoms: to the presence of their swelling (bombing). The bombing can have a different origin: a) microbial (due to the formation of gases by microorganisms - hydrogen sulfide, methane, ammonia, carbon dioxide); b) physical due to heating, freezing of the product or overfilling the can, as well as its deformation; c) chemical, caused by swelling of the bottoms due to the formation of hydrogen as a result of the action of canning filling acids on the metal covering the can.

The data of the external examination of the can are entered in the analysis protocol, after which the can is examined for the tightness of the package using the arbitration and simplified method.

A simplified method: the jar is freed from the label, wiped off the lubricating layer of petroleum jelly, tied with twine and immersed in water preheated to boiling. The amount of water should be 4 times the volume of the jar. The water should completely cover the jar immersed in it. The temperature of the water after immersing the jar in it drops, it must be maintained at a level not lower than 85 ° C. The jar is kept in hot water for 5-7 minutes.

Air bubbles appear on the surface of the water if the seal of the package of canned food is violated.

Hygienic examination of fruits and vegetables

Hygienic examination is subject to fresh and freshly frozen vegetables, dried vegetables, potatoes, fruits, berries and mushrooms, juices, drinks and vegetable, fruit, berry, salted and pickled vegetables, salted and pickled mushrooms.

The evaluation of these products is carried out in accordance with
Sanitary rules and norms SanPiN 2.3.2.560-96.

Research of fresh vegetables, fruits and berries
for their nitrate content. The content of nitrates is one of the important indicators characterizing the ecological and hygienic safety of food of plant origin.

The reason for the increase in the content of nitrates in these products is, as a rule, the excessive use of nitrogen fertilizers in agriculture, as a result of which the level of nitrates in soil, surface and ground waters increases, from where they enter food and feed agricultural products. In addition, nitrates are used as
food additives, for example, in sausage production, where their overdose is possible. It is also known about the possibility of using nitrates to falsify food products, as they help accelerate the ripening, in particular, melons (watermelons, melons, etc.)

A significant accumulation of nitrates in water and food products can cause methemoglobinemia in children and a number of diseases in farm animals. Nitrates can combine with amines and amides to form
carcinogenic effects of nitrosamines and nitrosamides.

The accumulation of nitrates in plant products occurs with varying intensity. So, with the same content in the soil - 80 mg / kg, they can be found in melons in quantities of 100-140 mg / kg, tomatoes - 115 mg / kg, cucumbers - 120 mg / kg, potatoes - 220 mg / kg. kg, cabbage - 280 mg/kg, beets - 420 mg/kg.

To determine the content of nitrates in food
various methods can be used. The method for determining the content of nitrates in fruit and vegetable products is set out in MU 5048-89. However, at present, express control using the MORION device is most widely used, although this device gives a rather large error (about 20%).

Practical work "Hygienic examination of the nutritional value and good quality of food products."

Assignment to students:

In accordance with the methods specified in the general provisions of the topic, conduct a hygienic examination of the nutritional value and good quality of food products: milk, meat, bread, fish, canned food.

Lesson topic: Medical and sanitary control over the catering of medical institutions

The value of studying the topic: consists in the implementation of knowledge and skills in conducting medical and sanitary control over the catering of medical institutions in the professional activities of a doctor, as well as in preparing students for future life.

Purpose of the lesson:

a) The purpose of studying the topic: familiarization of students with the principles of planning the catering units of medical institutions, sanitary requirements for interior decoration of premises, equipment and inventory, sanitary and hygienic requirements for the organization of the catering unit, contraindications for admission to work at food enterprises.

b) The learning goal of the lesson: students must learn to evaluate the design of the catering unit, the degree of sufficiency in equipping the catering unit, the rejection of ready-made meals in the catering unit and identify violations in the operating mode of the catering unit that can lead to food poisoning.

Educational tasks of studying the topic:

o development of preventive thinking among students;

o development of hygienic and ecological culture of students.

Topic study plan:

End of work -

This topic belongs to:

Hygienic and ecological Nutritional adequacy

for Health and Social Development.. State Educational Institution of Higher Professional Education..

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