Etiket Arşivleri: Pickling

Fermentation Lab Reports‎ > ‎Cucumber Pickling‎ > ‎Pickling v7

These can be made in a day or two in contrast to those that are fermented or brined and cured,a long-term process.In this process, it is important to use a good quality, clear, commercially prepared vinegar that is free from sediment with five percent acetic acid. Home-made vinegar should not be used.Distilled white vinegar helps keep the original color, while cider, wine or malt vinegar may slightly darken the food.Because the vinegar is part of the preservationprocess, it is important not to vary the amount recommended in the recipe. Use reliable, up-todate recipes.

Be creative in pickling fruits and vegetables.Feel free to add or omit herbs and spices, but do not alter the basic ingredients. The ratio of vinegar to vegetables is determined in recipes to insure their safety and quality.In this quick vinegar method, the fruit or vegetables are usually packed into jars, then covered with a hot vinegar solution. They are generally processed in a simmering hot water bath of 170 to 180°F. Some pickled foods can be safely open-kettle canned. Open-kettle canning,however, does contribute to a higher rate of spoilage and seal failures and is therefore not recommended.
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Fermentation Lab Reports‎ > ‎Cucumber Pickling‎ > ‎Pickling v5

Pickling, one of the most ancient ways to preserve food, relies on salty, acidic brine and spices and herbs to give foods distinctive flavors. Liquid spice and herb extracts help pickle processors achieve their flavor goals conveniently and consistently. Spice extracts provide precise flavor control, a cleaner, clearer brine and sterility, says Haley. The flavor and strength of the spice extracts are consistent from season to season. They are microbiologically very clean, so they will not lead to the growth of yeasts and molds in pickled products. The clear extracts can be measured precisely and dispersed easily in pickling brines. Extracts function well in both the fresh-pack and process methods of pickle manufacturing. For fresh-pack, whole or sliced cucumbers are placed in jars; brine is made up and filled into the jars. The jarred products are heated to 145°F to deactivate the pectinase enzyme in the cucumbers and then quickly cooled. They are stored for several days to equalize the flavors.

The cucumbers for process pickles ferment in a vat of salty brine until packaging. Then they are soaked to rinse out some of the salt, sliced or ground and packaged. Brine and flavors are added at 140°F. Cucumbers are among many vegetables and fruits that can be pickled. Onions, beets, bell peppers, cauliflower, carrots, olives, tomatillos, jalapeños, green tomatoes and watermelon also get flavor from the pickling process. In some more unusual applications, exotic fruit like tamarinds and some non-plant foods like herring, shrimp, eggs and bologna are pickled. Spice extracts for pickled products provide precise flavor control, a cleaner, clearer brine and sterility. The clear extracts can be measured accurately and dispersed easily in pickling brines. Discarded oversized cucumbers represent about 15 percent of the cucumbers produced for pickle manufacturing. Studies are underway focusing on the development of usable products for these currently unusable cucumbers. Two volatiles that can be extracted from these cucumbers have been found to be effective inhibitors of mold, yeast, and some pathogenic microorganisms. These volatiles have potential for use in a variety of food and cosmetic products, supplying a market for these waste cucumbers.

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Fermentation Lab Sheets‎ > ‎Cucumber Pickling

QUESTIONS

1. Write the parameters that effect the cucumber pickling

2. What is the main problem when you use big cucumber and why this problems occur?

DISCUSSION AND CALCULATIONS

1. Plot the lactic acid, ph and number of m/o versus time.

2. Discuss your results and determine the best vinegar and salt concentration.

Fermentation Lab Sheets‎ > ‎Cucumber Pickling ( FE 411 )

PURPOSE

To practice the production of cucumber pickling. By the way, to measure some parameters of the pickle.

THEORY

Pickle is a product that produced from vegetables and fruits are fermented by lactic acid bacteria in a brine has a specific salt concentration or in their self juice. Any kind of vegetables and fruits can be used for pickling. But, in whole world the most known and manufactured pickle type is cucumber pickle.

Lactic acid fermentation is the most important step occurs in the pickling. The fermentation occurs in anaerobic conditions, generally at 18-20 OC, for 2-8 weeks according to pickle’s content. While fermentation occurs, there is a transition between brine and raw material. The salt in brine passes into raw material and various compounds in raw material like minerals, sugars, and nitrogenous substances pass into brine. Lactic acid bacteria ferment the sugars.

Lactic acid bacteria ferment sugars with different pathways. Homofermentative lactic acid bacteria (Lactobacillus plantarum etc.) which are dominant in fermentation use the EMP pathway and produce only lactic acid. This kind of bacteria forms almost all lactic acid and end the fermentation. Heterofermentative lactic acid bacteria (Leuconostoc mesentereoides etc.) which generally start the fermentation use the HMP pathway and produce lactic acid, ethanol, CO2, acetic acid. Thanks to other compounds exception lactic acid by formed these bacteria; the pickle gets its taste and flavor.

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Pickling

PICKLING

• An important food preservation system combines salting to selectively control microorganisms and fermentation to stabilize the treated food materials.

• Pickling is one of the oldest, and most successful, methods of food preservation known to humans

•  The process when applied to vegetables is called pickling.

• When applied to meat it is called curing.

Pickling remains a major form of preservation in many countries because it:

(1) yields desirable organoleptic qualities;

(2) provides a means for extending the processing season of fruits and vegetables;Factors involved in vegetal fermentation

(3) requires relatively little mechanical energy input.

Salt

• exerts  a growth repressing action on certain microorganisms by limiting available water and dehydrating protoplasm, causing plasmolysis.

• 26.5 % sodium chloride at room temperature corresponds to saturation concentration.

• Salometer degree( a scale used in pickling industry)

• 0 % NaCl —– 0 degree

• 2.65 % NaCl—10 degree

• 26.5 % NaCl—100 degree (No free water available for microbial growth

Salt for pickling

• Every common salt is suitable as long as it is pure.

• Impurities or additives can cause problems.

• Salt with chemicals to reduce caking should not be used as they make the brine cloudy.

• Salt with lime impurities can reduce the acidity of the final product and reduce the shelf life of the product.

• Salt with iron impurities can result in the blackening of the vegetables.

• Magnesium impurities impart a bitter taste.

• Carbonates can result in pickles with a soft texture.

Salt concentration

• Lactic acid bacteria tolerate high salt concentrations.

• The salt tolerance gives them an advantage over other less tolerant species and allows the lactic acid microorganisms to begin metabolism, which produces acid, which further inhibits the growth of non-desirable organisms.

• Leuconostoc is noted for its high salt tolerance and for this reason, initiates the majority of lactic acid fermentations.

Important microorganisms in plants:
I- Pseudomonas, Bacillus, Chromobacterium, Enterobacter,

Escherichia, Flavobacterium
II- Lactobacillus, Leuconostac, Pediococcus

• We support group II and supress group I

• Less research on fermented vegetables compared to other fermented foods because  cheap,

• produced at small scale by traditional methods

• very little public health problems occured.

Lactic acid fermentations

Lactic acid fermentations are carried out under three basic types of condition:
I-dry salted    II-brined III-non-salted.

I- Dry salted fermented vegetables

• the vegetable is treated with dry salt.(3%)

• The salt extracts the juice from the vegetable and creates the brine.

• vegetable washed in potable cold water and drained.

• placed in a layer of 2.5cm depth in container (a barrel or keg).

• Salt is sprinkled over the vegetables.( repeated until the container is three quarters full.)

• A cloth is placed and a weight added to compress the vegetables and assist the formation of a brine in 24 hours , fermentation starts and bubbles of carbon dioxide begin to appear.

• Fermentation takes between one and four weeks =f( temp)

• Fermentation is complete: no more bubbles, then pickle can be packaged in a mixtures of vinegar and spices or oil and spices

SAUERKROUT FERMENTATION

• It is a perfect example of microbial succession.

• Shredding cabbage: ( sugar 2.4-6.4 %, if it is too high product will be too acidic) ( In Turkish style cabbage is divided into four rather than slicing)

• Washing : to reduce chromogens ( bacteria which produce undesired color) and to wash out contaminating yeast and mold.

• Salting : Optimum salt concentration is 2.5 %, ıt should be evenly distributed. Higher levels of salt ( 3.5 % ) will support the growth of pediococcus, low levels ( 1 % ) will support groth of Leuconostoc mesentroides.

• Pressing: To make it anaerobic

Microbial Succession

• First enterobacter ( gas producer) and erwinia ( produces cellulases and pectinases ) will grow.

• Later L. mesentroides will grow ( it is desired at this stage). It produces lactic acid ( 0.7 % ) PH drops and this will suppress growth of gram(-) bacteria.It also produces mannitol ( bitter taste) which can only be utilised by L. Plantarum. By this way it supports growth of L. plantarum.

• Finally L. Plantarum grows to produce more acid ( 2 %) and using mannitol reduces bitterness.

• Further growth of L. pentoaceticus  may increase acid to 2.5 %

• Opt. Temp. is around 21ºC.

• A variation of just a few degrees alters the activity of the microbial process and affects the quality of the final product.

• temperature control is one of the most important factors in the sauerkraut process.

• A temperature of 18º to 22º C is most desirable for initiating fermentation since this is the optimum temperature range for the growth and metabolism of L. mesenteroides.

• Temperatures above 22ºC favour the growth of Lactobacillus species.

Sauerkrout defects

– High temperature fermentation suppresses growth of Leuconostoc( which produces desired flavor compounds)

– too long fermentation may favor the growth of gas forming L. Brevis.

– Soft krout: may be due to faulty fermentation, exposure to air and excessive pressing.

– dark brown or black krout: air exposure, uneven salting ( salt burn) or high temperature.

– pink krout: caused by red asporagenous yeast growth

– slimmy or ropy krout: caused by encapsulated varieties of L. Plantarum ( edible but not salable)

II- Brine salted fermented vegetables

• Brine (salt solution) is used for vegetables which inherently contain less moisture.

• The strong brine solution draws sugar and water out of the vegetable, which decreases the salt concentration.

• It is crucial that the salt concentration does not fall below 12o salometer. (add extra salt periodically to the brine)
• The microbial populations of the fermenting vegetables = f ( the concen. of salt, temp. of the brine, the availability of fermentable materials and the numbers and types of micro-organisms present at the start of fermentation.

• Rate of the fermentation = f (concentration of salt, temperature.)

• Most vegetables can be fermented at 12.5o to 20o salometer salt( sauerkrout microbial succession)

• About 40o salometer, the sequence is skewed towards the development of a homofermentation, dominated by Lactobacillus plantarum.

• About 60o salometer,  the lactic fermentation ceases to function and if any acid is detected during brine storage it is acetic acid, presumably produced by acid-forming yeasts which are still active at this concentration of salt

• Brining vegetables in salt, and the resultant lactic acid fermentation, is an ancient form of preservation.
Two new methods of pickling cucumbers, which represent the largest volume of a single vegetable preserved by pickling, have been developed during the 1900s. Both methods use lower salt concentrations and result in a milder product.

I- pasteurization and direct acidification, was developed and began commercial production in the 1940s.

II- refrigeration and direct addition of acid and preservative, was introduced in the 1960s.

Relative quantities of cucumbers preserved by the 3 pickling methods in 1984
were:
brine fermentation, 43%;                 pasteurization, 43%;                         refrigeration, 14%.

A-Pasteurized Pickles

• Vegetables which are fresh or only partially fermented may be preserved by the addition of vinegar or acetic acid and subsequent pasteurization.

• Vinegar alone is not sufficient to insure product safety, and so requires an additional form of preservation such as heat or refrigeration.

• The steps involved in producing pasteurized or ‘fresh-pack’ pickles are the following:

• slice, cube, or dice product;

• place in clean container;

• mix water, salt, vinegar, sugar, spices and bring to boil;

• add hot brine to container;

• seal and pasteurize.

Two possible pasteurization methods include:

(1) heating such that the center of the jar or can reaches 75 °C, and holding for 15 min, followed by a prompt cooling to 35 °C or below,

(2) heating at 70 °C for 10 min, followed by prompt cooling

• The pasteurization process essentially destroys spoilage microorganisms and prohibits fermentation from occurring.

• Both acid-forming bacteria, which are active in brine fermentation, and yeasts, which cause gas production, are destroyed by pasteurization.

• The pasteurization process inhibits polygalacturonase, the enzyme responsible for pickle softening.

• Enzyme activity may also be controlled through use of appropriate salt concentrations.

• Calcium chloride, and KAl(SO4) is often added to brine to aid in firming cucumber pickles

• Pasteurized pickled products have steadily gained in popularity, and have a very different flavor and texture to that of fermented pickled products.

B-Refrigerated Pickles

Represent the latest development in pickling technology, are produced by direct acidification and addition of sodium benzoate or another preservative.

• In these nonfermented pickles, the preservative takes the place of pasteurization in preventing spoilage of the product.

• essentially the same as that used for pasteurized pickles, but instead of pasteurizing, the sealed containers are refrigerated.

• It is essential that this type of pickle is kept refrigerated throughout the production process and during subsequent consumption.

C-Fermented Pickles

• There are three general methods which may be used for cucumber fermentation;
(1) salt stock;       (2) genuine dill; and           (3) overnight dill.
(1)Salt stock

• involves fermentation in 5–8% ( salt conc. increased 1%/week up to 16 % salt) until all fermentable sugars have been converted to acids and other  products. ( can be stored for several years)

• Desalting to an acceptable organoleptic level (2–2.5% salt) is carried out by leaching in water.( quick leaching in warm,43-54 C, water, 10-14 hrs)

• Salt stock pickles make up the largest percentage of fermented pickle products.

• The controlled fermentation of pickles has been a goal of the industry for years.

• In particular, most processors now acidify and purge tanks after brine is added.

• Acidification inhibits the growth of acid-sensitive Gram-positive and Gram-negative bacteria and, therefore, favors the growth of lactic acid bacteria.

• Purging decreases the incidence of bloating, which results from carbon dioxide production by both the fermenting microorganisms and the cucumber itself.

BLOAETER DAMAGE ( HOLLOW CUCUMBER) 

Bloater damage occurs due to high level of gas production during fermentation.

Reasons: large cucumbers (with thick skin) higher fermentation temperatures ( which supports growth of gas producing bacteria such as coliforms, heterofermentative lactic bacteria and yeast ).

Preventing: Inoculating with L. Plantarum purging out produced CO2 with nitrogen gas definately using small size cucumbers will
(2)Genuine dill pickle

• fermented in 4–5% salt, to which dill weed, garlic, and other spices have been added.

• 3–6 weeks for fermentation to reach completion,

• where the lactic acid content is 1.0–2.5% and the salt content is 3–3.5%.

• not require desalting, ( sold  with the filtered fermentation liquor. )

• It should be thightly closed, can be kept 12 months, otherwise film yeast will grow and utilize lactic acid( addition of 0.1 % potassium sorbate is helpful to reduce this risk).

•  (first) Enterobacter clocea,  (second) Leuconostac mesentroides, (third) Lactobacillus plantarum
(3)Overnight dill

• Produced by soaking cucumbers in to 20 salometer degree solution ( containing salt, vinegar, dill )

• Actually there is very little or no fermentation, only taste changes due to replacement of some plant juice with solution.

• The product must then be refrigerated, and should not be kept longer than 6 months due to its extreme perishability.

TOMATO PICKLE

•  Same procedure with cucumber pickling.

• Green tomatoes are used.

• When color turns from green to cream color it is the right time to end process

PEPPER PICKLE

• 7 kg pepper + 300-400 g acetic acid + 5 % salt solution

• In only salt solution color will be darker,

• in acetic acid solution color will be yellow(desired)

Pickling Presentation

PICKLING
An important food preservation system combines salting to selectively control microorganisms and fermentation to stabilise the treated food materials.
the oldest, and most successful, method of food preservation known to humans
The process when applied to vegetables is called pickling.
When applied to meat it is called curing.

a major form of preservation because it:
(1) yields desirable organoleptic qualities;
(2) provides a means for extending the processing season of fruits and vegetables;
(3) requires relatively little mechanical energy input.

salt, temperature, and anaerobiosis creates environment necessary for a successful lactic acid fermentation.

Within just a few hours, lactic acid bacteria will begin to grow, a lactic acid fermentation will commence, and the number of competing organisms will decline.

Salt
growth repressing : on microorganisms by limiting available water and dehydrating protoplasm, causing plasmolysis.
26.5 % sodium chloride at room temperature corresponds to saturation concentration.
Salometer degree( a scale used in pickling industry)
0 % NaCl —– 0 degree
2.65 % NaCl—10 degree
26.5 % NaCl—100 degree (No free water available for microbial growth

Salt for pickling.
Impurities or additives can cause problems.

Salt with chemicals to reduce caking should not be used as they make the brine cloudy.

Salt with iron impurities can result in the blackening of the vegetables.

Magnesium impurities impart a bitter taste.

Carbonates can result in pickles with a soft texture.

Important microorganisms in plants:
I- Pseudomonas, Bacillus, Chromobacterium, Enterobacter, Escherichia, Flavobacterium
II- Lactobacillus, Leuconostac, Pediococcus

We support group II and supress group I

Less research on fermented vegetables compared to other fermented foods
-because cheap,
-produced at small scale by traditional methods
-very little public health problems occured.

The lactic acid fermentation of vegetables depends not on any single organism, but rather on a consortium of bacteria

Eventually, the initial microbial population gives way to other species that are less sensitive to those inhibitory factors.

Microbial ecologists refer to these sorts of processes as a succession.

Lactic acid fermentations
are carried out under three basic types of condition:

I-dry salted

II-brined

III-non-salted.

I- Dry salted fermented vegetables
the vegetable is treated with dry salt.(3%)

The salt extracts the juice from the vegetable and creates the brine.

vegetable washed in potable cold water and drained.

placed in a layer of 2.5cm depth in container (a barrel or keg).

Salt is sprinkled over the vegetables.( repeated until the container is three quarters full.)

compress the vegetables to assist the formation of a brine, fermentation starts and bubbles of carbon dioxide begin to appear.

Fermentation=f( temp) : one and four weeks

Fermentation is complete: no more bubbles, then pickle can be packaged in a mixtures of vinegar and spices or oil and spices

SAUERKROUT FERMENTATION

It is a perfect example of microbial succession .

Shredding cabbage: ( sugar 2.4-6.4 %, if it is too high product will be too acidic) ( In turkish style cabage is divided into four rather than slicing)

Washing : to reduce chromogens (coloring bacteria) and to wash out contaminating yeast and mold.

Salting : Optimum salt conc. is 2.5 % (evenly distributed)
3.5 % salt will support pediococcus,
1 % salt will support Leuconostoc mesentroides.

Pressing: To make it anaerobic

Mirobial Succession
1-enterobacter ( gas producer) and erwinia
( produces cellulases and pectinases )
2- L. Mesentroides : produces lactic acid ( 0.7 % ) PH drops and this will suppress growth of gram(-) bacteria. It also produces mannitol ( bitter taste) which can only be utilised by L. Plantarum. By this way it supports growth of L. plantarum.
3- L. Plantarum grows to produce more acid
( 2 %) and using mannitol reduces bitterness.
Further growth of L. pentoaceticus may increase acid to 2.5 %

temperature control is one of the most important factors in the sauerkraut process.

A temperature of 18º to 22º C is most desirable( optimum temp. range for the growth and metabolism of L. mesenteroides. )

Temperatures above 22ºC favour the growth of Lactobacillus species.

Packaging and processing

thermally processed, at about 75°C, prior to packaging in cans or jars. (commercially sterile and are stable at room temperature.)

There is also a market for non-pasteurized, refrigerated sauerkraut that is packaged in glass jars or sealed plastic bags (polybags). ( antimycotic agents, such as benzoate and sulfite salts are added)

Sauerkrout defects

High temperature: suppresses Leuconostoc( which produces desired flavor compounds)

-too long fermentation: favor gas forming L. Brevis.

-Soft krout: due to faulty fermentation, exposure to air and excessive pressing.

-dark brown or black krout: air exposure, uneven salting ( salt burn) or high temperature.

-Pink krout: coused by red asporagenous yeast growth

– slimmy or ropy krout: caused by encapsulated varieties of L. Plantarum ( edible but not salable)

Kimchi

the Korean version of sauerkraut is called kimchi.

Kimchi is usually made from cabbage, but other vegeta-bles, including radishes and cucumbers also used.

Garlic, green onion, ginger, and red peppers are among the typical ingredients, but fish, shrimp, fruits, and nuts, can also be added.

II- Brine fermented vegetables
Brine : used for vegetables which contain less moisture.

strong brine draws sugar and water out of the vegetable.

salt concentration should not fall below 12 salometer

the microbial populations = f( the concen. of salt, temp. of the brine, the availability of fermentable materials and the numbers and types of micro-organisms present at the start of fermentation.

rate of the fermentation=f( concentration of salt, temperature.)

Most vegetables can be fermented at 12.5o to 20o salometer

about 40o salometer, homofermentation, dominated by L. plantarum.

(about 60o salometer) the lactic fermentation ceases only acetic acid, by acid-forming yeasts, is observed.

A-Pasteurized Pickles
(Fresh-packed pickles )

Vegetables which are fresh or only partially fermented may be preserved by the addition of vinegar or acetic acid and subsequent pasteurization.

Vinegar : alone is not sufficient to insure product safety, and so requires an additional form of preservation such as heat or refrigeration.

The steps involved in producing pasteurized or ‘fresh-pack’ pickles are the following:

• slice, cube, or dice product;
• place in clean container;
• mix water, salt, vinegar, sugar, spices and bring to boil;
• add hot brine to container;
• seal and pasteurize.

The pasteurization process inhibits polygalacturonase, the enzyme responsible for pickle softening.

Enzyme activity may also be controlled through use of appropriate salt concentrations.

CaCl2 and KAl(SO4) added to brine to aid in firming cucumber pickles

Pasteurized pickled products have steadily gained in popularity( very different flavor and texture)

B-Refrigerated Pickles

latest development: direct acidification and addition of sodium benzoate or another preservative.

non-fermented pickles, the preservative takes the place of pasteurization

a crisp, crunchy texture and bright green color.

refrigerated pickles have a shorter shelf-life than fresh-packed pickles.

C-Fermented Pickles
cucumber fermentation; (1) salt stock; (2) genuine dill; and (3) overnight dill.

(1)Salt stock

fermentation in 5–8% ( salt conc. increased 1%/week up to 16 % salt) until all fermentable sugars have been converted to acids. ( can be stored for several years)

quick leaching in warm,43-54 C, water, 10-14 hrs to 2–2.5% salt

make up the largest percent of fermented pickle products.

processors acidify and purge tanks after brine is added.

Acidification inhibits the growth of acid-sensitive Gram-positive and Gram-negative bacteria and, therefore, favors the growth of lactic acid bacteria.

Purging decreases the incidence of bloating.

BLOAETER DAMAGE ( HOLLOW CUCUMBER)
due to high level of gas production.
Reasons:
large cucumbers (with thick skin)
higher fermentation temperatures ( which supports growth of gas producing bacteria such as coliforms, heterofermentative lactic bacteria and yeast ).
Preventing:
-Inoculating with L. Plantarum
-purging out produced CO2 with nitrogen gas
-using small size cucumbers

(2)Genuine dill pickle

fermented in 4–5% salt, to which dill weed, garlic, and other spices have been added.

3–6 weeks for fermentation to reach completion,

where the lactic acid content is 1.0–2.5% and the salt content is 3–3.5%.

not require desalting

thightly closed, can be kept 12 months, otherwise film yeast will grow and utilize lactic acid( addition of 0.1 % potassium sorbate is helpful to reduce this risk).

(first) Enterobacter clocea, (second) Leuconostac mesentroides, (third) Lactobacillus plantarum

Dill (dereotu)

(3)Overnight dill

soaking cucumbers in to 20 salometer degree solution ( containing salt, vinegar, dill )

very little or no fermentation, only taste changes due to replacement of some plant juice with solution.

product must then be refrigerated: keep < 6 months

TOMATO PICKLE
same procedure with cucumber pickling.

Green tomatoes are used .

When color turns from green to cream
color it is the right time to end process

PEPPER PICKLE
7 kg pepper + 300-400 g acetic acid
+ 5 % salt solution

In only salt solution color will be darker,

in acetic acid solution color will be yellow(desired)