Topic 3 makes pickles and detects nitrite levels
1. Understanding the production process and attention. (focus)
2. To determine the change in nitrate levels in central asia in pickles using a beige method. Harder
ConcernsFood securityProblem。
Pickles
1.PicklesBacteria and principles used
(i) bacteria: 0 lactate
`specific: gas, soil, vegetative surfaces, human or animal intestinal tracts, etc
V metabolic type: hexaoxin type
Common types: lactate streptococcus and bacterium lactate, of which bacterium lactate
, often used to produce yogurt
(2) fermentation principle: under fluorinated conditions, glucose is decomposed by lactation。
2. Process for making pickles
Raw material processing: selection of fresh vegetables, repairing, washing, drying and cutting into strips or slices
Saline water formulation: boiled and cooled at a ratio of 4 to 1 water quality
Platts: when you put vegetables in half, you put them in the spices, you keep them in 80% full and you inject them
It's made of salt water, so it doesn't cover all the dishes
The fermentation of the altar: cover it up and fill the sink along it for the duration of the fermentation
Effects of internal temperature
Done
3. Pickled conditions and key
(1) condition: control of the use of salt, temperature and salt during the pickled process. Temperature
High, low salt consumption and short pickles can easily cause bacteria to breed in large quantities and increase nitrite levels。
(2) key: the core step in pickled pickles is lactate condensation, selection of containers, preparation of salt water, matching
The sauce is a key step in the making of pickles。
[cooperative exploration]
Explore 1: why is milk with antibiotics not fermented to yoghurt?
Tips: yogurt is made on the fermentation of yogurt, and antibiotics can kill the yogurt or not
Make it grow。
Explore 2: whose nutritional value is sour milk compared to fresh milk
Why
Tip: oxy milk. Because milk is fermented and turns big molecular matter into small molecular matter, and it's easy to be exposed
Body absorption。
Explore 3: why often fill the sink of the pickles during fermentation
Tips: anaerobic environment necessary to ensure fermentation of lactate in the altar。
[ thinking up ]
1. Pickle fermentation process
Pickles accumulate in fermentation because of the fermentation of the yogurt
The pickle fermentation process is divided into three stages, depending on the activity of the microbe and the accumulation of lactate。
(1) early fermentation
1 the types of microorganisms involved: are mainly active with acid-resistant compost and yeast。
2-fermentation process: this phase is mainly a high consumption of 02 and produces more c02s, which is gradually taking place within the forum form
Be oxygen-free。
3 fermentation characteristics: at this time, the acidity of pickle is approximately 0. 3% thallium. 0. 4%, primary stage of pickles
The vegetables are salty and not sour。
(2) medium-term formality
1 the main type of fermented micro-organisms: lactate。
2 reason: lactate accumulates as a result of early lactation, ph drops and anaerobic formation。
3 fermentation characteristics: at this time, the accumulation of lactate can reach 0. 6% 〜 (). 8% and ph 3. 5 〜 3. 8. Big intestines
The movement of bacterium, fungi, yeast, fungi is inhibited. This period is full of pickles
Pickles smell good。
(3) post-fermentation
One major fermented micro-organism: still lactate。
Two fermentation characteristics: lactate levels continued to increase during this period to over 1. 0 per cent. When lactate levels up
By more than 1. 2 per cent, the activity of the lactacid bacteria was inhibited and the rate of fermentation slowed down or even stopped. This stage
The pickles are sour and the flavors don't match。
Care to make pickles
(1) choice of the pickle table: the choice should be for the fire to be well prepared, non-fissile, non-discretionary eyes, the platform to be deep and the lid to fit
The pickle pot。
(2) saline water is formulated by a water quality ratio of 4:1 and boiled and cooled for use. Cooking has two major effects
Remove oxygen from the water. The second is bacteria from saline water。
(3) when the material is 80% full, the salt water is added to the whole dish and the altar is covered。
(4) the seal shall be filled with water in the sink along the lid, and shall be dug and strictly sealed to ensure the lactacid effect
Anaerobic environments for fermentation, with attention to frequent recharge during fermentation。
I. The description of pickles production is incorrect ()
A. The ratio of clean water to salt is 4:1
B. Length of fermentation time influenced by indoor temperature
C. Pickles should choose the fire, the sandless eye, the lid
D. Fermentation does not require water recharge to the sink
The process of making pickles is to place fresh vegetables in closed containers for some time
It's fermented. In the production process, salt water is formulated at a ratio of 4:1 to the quality of fresh water and salt
The length of yeast is influenced by indoor temperature; the knob table should choose the fire, the sandless eye, the lid match, no
Qualified pickles are prone to fermentation; in the fermentation process, care is taken to regularly replenish the water in the sink so that
Make an aerobic environment. So d's wrong。
Answer d
2. Answer the following questions concerning pickles:
(1) when making pickles, salt water needs to be boiled. The aim is to reduce production time,
Someone will add a small amount of pickles to the cooled salt water, and the purpose of adding the pickles will be
(2) in the making of pickles, the process of lactation is the process of lactation, i. E. The process of lactation
The process occurs in lactate cells。
(3) factors affecting nitrite levels during the production of pickles are, and
Etc。
(4) during the period from the beginning to the best of pickles, pickles become acidic internal
The pattern of the growth of lactate and other fungs in the pickles is,
Reason 0
[alysis] (1) high temperature can kill fungs, so salt water used in making pickles is boiled. Pickle
The liquid contains more lactate, and a small amount of pickles is added to the cooled salt water, allowing the number of lactate
The volume has increased rapidly in a relatively short period of time。
(2) the pickles are white and the fermentation process is actually an aerobic respiration of the yogurt
The process occurs in the cell mass of the lactate bacteria, which is the original nucleus, the non-cellary nucleus。
(3) in making pickles, care must be taken to control the timing, temperature and salt use of pickles, which are too high
Low salt consumption and short pickles can easily lead to a high number of fungs and increased nitrite levels。
(4) the aerobic fermentation of yogurt produces large amounts of lactate, resulting in a decrease in ph in pickles, resulting in other bacterial numbers
Reduction in volume and increase in the number of lactate。
[the answer is] the eradication of fungi increases the amount of yogurt (2) anaerobic respiratory cell (3) temperature
The salt most used for pickled time is the increase in the number of yogurts, which are less numerous than the fungs
Acid resistance
Measurement of nitrite levels
1. Nitrite
Physically white powder, soluble in water
Application as food additives in food production
Wide distribution, in foods such as vegetables, pickles and bean powder medium
Intoxication when total human intake is 0. 3 〜05g: total intake
Hazard
When it reaches u3g, it will kill one
No more than 30 mg/kg of meat products: no more than 20 mg/kg of pickles,
Our health standards
Infant milk powder should not exceed 2 mg/kg
Most excreted with urine, but under certain conditions, i. E. Appropriate ph, temperature
Metabolism
It turns into a carcinogen, nitrazine
2. Measurement of nitrite levels
(1) rationale: nitrites and amino-phenyl sulfuric acids react with severe nitrogenization under hydrochloric acid conditions,
Combine with n-11 ethylenedichlor into rose-red dyes, which can be compared by visual means, roughly estimated
Count its content。
(2) method: colour method. Through sample and standard chromosomal liquids after reaction to solution and reagents that's right
In comparison, the nitrite content of the solution to be measured is derived。
(3) validation operations: one colour for the preparation of a solution, one standard colour for the preparation of a sample treatment fluid。
[cooperative exploration]
Explore 1: why do you eat more fresh vegetables in everyday life than pickled vegetables
Tips: pickled vegetables have high levels of nitrate in central asia, and nitrite can be transformed into sub-sample under certain conditions
Nitamine. Nitamine is harmful to humans。
Explore 2: nitrite can be transformed into a carcinogen and why can it be used as an additive in food production
Note: nitrite does not pose a health hazard to the extent permitted, and nitrite only
Conversion to carcinogens is only possible under certain conditions。
[ thinking up ]
1. Nitrite content determination
(1) flow chart for determination of nitrite content:
Formulate solution preparation standard colour - t-preparation sample position positive
(2) preparation of liquid flow charts for sample processing:
[wi] squeeze, extract part of the leachate in the steam water
Vibration
I pick-up in i pick-up capacity bottles
Oxygen
One filter. Done
(3) calculation of nitrite content:
Sample level of nitrate in central asia (mg)
Nitrate content =
Sampling volume (40 ml filter quality) (kg)
2. Determination of reagents, pharmaceuticals and effects used in the experiment
Serial number reagents, pharmaceutical effects
1 heavy nitrogen reaction to amino-phenyl sulfate and nitrite
2 hydrochloric acid adjustment ph to acidity
N-1-tsai gyÖngi combines with the product of a heavy nitrogen reaction to produce rose red
Ethylene hydrochlorate dye as an indicator to determine nitrite levels
4 silicate drying agent for dry sodium nitrate
Standard colour for dry sodium nitrite prepared concentrations liquid
Cadmium chloride, soluble in evaporated water and used as nitrous acid after acidization
The extraction agent for chlorinated iron salt
Sodium hydroxide 7 and excessive hydrochloric acid to create an alkaline environment
Aluminium hydroxide 8 as an adsorption agent to discolor and clarify pickle filters
9 vacuum water as solvent
I. With regard to the effects of nitrite in diet on human health, the following statement is correct: ()
A. The nitrite in the diet is excreted with urine
B. Carcinogenic effects of nitrite accumulation in humans
C. Nitrite can only be transformed into a carcinogen under specified conditions
D. Nitrite has no impact on human health
The study shows that nitrites in diet do not generally endanger human health when ingestion
It's not until a certain number is reached. The vast majority of nitrite is excreted with urine and does not itself cause cancer
Used but converted into carcinogens under certain conditions。
Answer c
2. A student measured nitrite levels every 3 〜4d during pickles, as follows:
Table
Changes in nitrite content during pickles (mg/kg)
The altar
Nitrate content
♪ 1 ♪ 2 ♪ 3 ♪
Pick up the skyscraper
0. 150. 150. 15 in front of the seal
4d0. 60(()2()(). 8()
7d0200. 10. 60
10d0. 100. 050. 20
14dojo0. 050. 20
(1) the method used in this experiment to determine the nitrite content is
(2) the correct description of the principles for determination of nitrite is ()
A. Dinitrous acrylic acrylic acoustics
B. Cosmetics of acidization
C. A nitric acidization and a visible colour
D
(3) a map of changes in the nitrite content during pickled pickles from table 1。
(4) analyse the causes of changes in nitrite levels in combination with the curve and table data。
(5) what is the difference between the levels of nitrite in the 3 pickles? Why
The principle of this risk is that nitrite and aminobenzene sulfate are subject to hydrochloric acid acidification. Fire
Resist with the visible agent only after renitrous reaction, then with the known standard colour fluid that's right
In comparison, nitrite levels are estimated. In addition, attention should be paid to analysing trends in data
Instead of looking at a specific value. Changes in nitrite levels and the amount of fungus in pickled pickles
The more fungus there are, the higher the nitrite。
[answer] (1) color method (2)c
(3) as shown in the figure below:
(4) as pickles begin to be salted, the environment in the jar is conducive to the breeding of the bacteria of the bastard (including some nitrate)
The bacteria contribute to the reduction of nitrate to nitrite. But as the time for pickling increases,
Lactacid bacteria are also proliferating in large quantities, with some inhibiting effect on nitrate reduction, resulting in a negative impact on growth and reproduction
The noise caused a further decrease in the amount of nitrate in pickles in central asia
(5) the three pickles contain the lowest levels of nitrate in central asia, no. 2, the largest being no. 3. Quinta 3 nitro
It's probably contaminated during pickles
1. The following description of lactate is incorrect ()
A. There is a wide variety of lactate bacteria, common in streptococcus and bacterium lactate
B. Wide distribution in nature, including air, soil, phytowatch, human and animal intestinal tracts
C. All the yogurts in a pickle jar form one species group
D. Lactus is a strict anaerobic microbe
[alysis] there is a wide variety of yogurt, common species of yogurt strept and bacterium lactate, in nature
There's a very wide distribution, but there's a common characteristic of all lactate, which is the conversion of sugar under anaerobic conditions
For lactate. A pickle jar typically includes a variety of yogurt, and x is generally not a species。
Answer c
When a person makes pickles using lactate, they are corrupted by improper operation. That's what makes pickles rot
Reason ()
1 can of mouth closed to oxygen, inhibiting the growth and reproduction of lactate
2 cans are closed and oxygen inhibits the growth and reproduction of lactate
Three cans are closed and oxygen inhibits the growth and reproduction of other rota
4 cans are not closed, contributing to the growth and reproduction of anaerobic fungi
A. 1 © b. 24
C. 23d. 14
This is a study of the application of pickle production principles and the ability to use knowledge to explain practical problems。
Lactate is anaerobic bacteria that can decompose glucose into lactate without oxygen. When making pickles
Vegetable cans are not closed, oxygen enters the cans, inhibits the fermentation of lactate; simultaneously, the oxygen enters
The growth and reproduction of anaerobic fungus in the can, which causes pickles to rot。
"b."
3. The following description of the principles for determination of nitrite content is incorrect:
[indicator 05520007]
A. The nitrite is colored and red for roses
B. Sample fluids can be approximated by a standard liquid matching at known concentrations medium
Nitrate content
C. Darkness of nitrite at different concentrations
D. No change in the physico-chemical properties of nitrites following visible reactions
[decomposition] the principle for measuring nitrite levels is that, under hydrochloric acidicity, nitrites are first associated with
Reacting on amino-phenyl sulfate and then forming rose-red dyes with n-1
In the process, the nitrites have undergone significant changes in their physico-chemical properties。
Answer d
4. The method of making pickles in rural areas is that fresh vegetables are sorted, cleaned and put in clean
Wash and rinse the pickles with white wine and then add salt water, spices and some of the pickles
Water”. It's sealed and placed in the shade, and the best ambient temperature is 28 °c30, and sometimes pickles are salty
No acids” or “no acids”, the former being too salty and the latter too salty. In a laboratory or factory
In the production of pickles, nitrite levels from pickles are tracked。
(1) the purpose of wiping the pickles with white wine is
(ii) why seal the dish
If there were cracks in the kitchen, what would happen
(3) if pickles are made “saline but not sour”, the most likely reason is
(4) the effect of the addition of "chen pickle" is 。
(5) by mid-fermentation, the anaerobic state is formed, the lactacid bacteria are active and a large amount of lactate is produced to make the milk
Accumulation of acids of 0. 6% 〜 0. 8% and ph 3. 5 〜 3. 8, with a test analysis of the activities of other microbes in this time
Situation and cause:
(6) the level of lactation continues to increase in the post-fermentation period, and the rate of fermentation slows down when it reaches more than 1. 2%
Even stop, mainly because:
The purpose of wiping the pickles with white wine is to disinfect and kill bacteria. (2) lactus is anaerobic
The object, which causes an oxygen-depleted environment after sealing; there are cracks in the kitchen, which will lead to the non-normal growth of the lactacid bacteria and some of the complications
A lot of bacteria
