fruit & veg. canning tech

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Equipments Used In Canning Process

Assignment Submitted

Towards Partial Fulfillment of the Requirements for the Course of

TECHNOLOGY OF FRUITS AND VEGETABLES (MTF-104)

By

Dhond Ravikumar S. (MTF/2011/06)

M. Tech Food Technology, 2011-13

Under the Supervision of

Dr. Shubhra Bhargava

AMITY INSTITUTE OF FOOD TECHNOLOGY

I-1 BLOCK, 4TH FLOOR, AMITY UNIVERSITY

SECTOR-125, NOIDA 201303, U.P., INDIA

SEPTEMBER 2011


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Canning

Introduction:

The process of sealing of foodstuffs hermetically in containers and sterilization them by heat for

long storage is known as canning.

In 1804 Appert in France invented a process of sealing foods hermetically in containers and

sterilization them by heat.

Appert is known as Father of canning.

Canning is the process of sterilizing and sealing foods in airtight containers to preserve them.

To retain nutrients and optimum quality, preserve fruits and vegetables when at their peak of

Freshness. Clean the food thoroughly before processing. Salt and/or sugar may be added to

Canned fruits and vegetables but these ingredients are not essential for a safe product

Food Preservation in the 21st Century:

Bacteria-Primary concern in home canning Viruses-May cause disease Parasites-May cause disease Mold-Causes spoilage, toxins are carcinogenic Yeast-Causes spoilage, toxins are carcinogenic

Primary objective:

Destroy the most heat resistance pathogenic Spore-forming organisms --- ex.- Clostridium Botulinum in products > pH 4.6

Secondary objective:

Destroy vegetative and spore-forming microorganisms that cause spoilage. Spoilage spore-formers are usually more heat resistant than pathogenic spore formers. Principal of canning process: Destruction of spoilage organisms within the sealed container by means of heat.

Two Methods of Canning

1. Boiling Water Canning Used for high-acid foods

2. Pressure Canning


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Used for low-acid foods. Can also be used for high-acid foods but might result in a soft texture.

High-Acid Foods (pH < 4.6)

All fruits, except for: figs tomatoes, and melons

Rhubarb Fermented pickles, such as sauerkraut Acidified foods, such as pickles and tomatoes

Low-acid Foods (pH > 4.6)

All vegetables, except for rhubarb Meats Poultry Seafood Soups Mixed canned foods (low-acid + high-acid)

Why Two Methods of Canning?

Yeast, molds, and most bacteria are killed at boiling temperatures -- 212F at sea level. C. botulinum forms spores that require higher temperatures for destruction in a

reasonable period of time -- usually 240F or above at sea level.

Packing Methods

Raw Pack

For foods that lose shape when cooked. Place raw food directly in jars. Pour boiling hot liquid over the food. Pack firmly, do not crush. Add jars carefully to warm canner to prevent jar breakage from heat shock. Preheat water to 140oF before putting raw-packed foods into boiling water bath.


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Hot Pack

Preferred method for most foods. Food is cooked in liquid before packing. Cooking liquid is then poured over food in jar. Less floating of food pieces in the jar. Better food color and flavor. Easier to pack, foods more pliable Heat in preparing kills some microorganisms. Preheat water to 180oF before putting into boiling water bath.

Canning Equipment:

Pressure Canners

Flat rack in bottom Pressure regulator or indicator:

Dial or weighted gauge Older models have petcocks

Ventpipe for pressurizing Safety valves or overpressure plugs Safety locks when pressurized Rubber gaskets in lid (metal to metal seal)

Replacement Parts

Dial gauges, when inaccurate Gaskets (sealing rings)

Every 2 years usually


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Rubber overpressure plugs Every 2 years

Vent pipes if clogged Air vent/cover lock from lid Weighted gauges or dead weight if lost

Processing Time Affected by:

pH value of the food Composition of the food

- Viscosity

- Tightness of pack

- Convection vs. conduction transfer of heat

- Starches, fats, bones

Preparation style of food Initial temperature of food as it is filled into jar Temperature of processing Size of jar Shape of jar Each food and preparation style has its own processing time so always use a tested recipe. Time differs with size of jar. Too little = under processing spoiled or unsafe food Too much = over processing overcooked

Boiling Water Bath:

Have water simmering (180oF) in canner, high enough to cover jars when filled (aboutsix inches for most loads).


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Hot packed jars = simmering water Raw packed jars = warm to hot water

Place jars on rack in canner. Add more hot water if necessary, once jars are in canner. (Never pour hot water directlyonto raw-packed jars). Start counting processing time after water returns to a full boil. Adjust processing time for altitudes over 1,000 feet. If processing foods for more than 30 minutes, water should be two inches over jars when

process begins.

If water stops boiling at any time during process, bring the water to a boil and begin theprocess over.

Headspace

Space in the jar between the inside of the lid and the top of the food or its liquid. Check canning directions for that correct headspace for each food. Usually:

1/4 for jellied fruit products 1/2 for high-acid foods, such as fruits, tomatoes, and pickles

1 to 1-1/4 forlow-acid foods

Too little:

Food may bubble out during processing. Deposit on rim may prevent proper sealing.

Too much:

Food at the top is likely to discolor. Jar may not seal properly, because processing time not long enough to drive all

the air from inside the jar.


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Process flow chart of canning:

Selection of the raw materials

Grading (Hand or machine)

Washing (25-50 ppm of chlorine as detergent)

Peeling {Hand, steam, mechanical, lye ( 1-2 % caustic soda for

30 sec. - 2 min), flame peeling}

Cutting

Blanching (1800F2000

F for 3-5 min)

Cooling (cold shock)

Filling and syruping or brining

Exhausting

Sealing (740

c Temp.)

Processing (for acidic 1000c and non acidic 1150

c - 1210

c foods temp. is)

Cooling

Storage (cool and dry place)


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Canning Equipments:

Grading

Screw grader:

According to Size and color or obtain uniform quality.This is done by mannualy or by screw grader or Roller grader.

Roller grader:

Washing:

Spray washing:

One gram of soil contain 1012

spores of microorganism.Root crops that loosen in soil are washed by soaking in water

containing 25 to 50 ppm chlorine (as detergent).

Steam washing:

Peeling:

1. Hand Peeling:This is done in case of fruits of irregular shape, e.g. Mango,

Papaya.


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2. Steam Peeling:

Free-stone and clingstone peaches are steam peeled in different

ways.

3. Mechanical Peeling:

This is done in case of apple, peaches, pineapple and

cherries.

4. Lye Peeling:Fruits like peaches, apricots, sweet orange, mandarin

oranges and vegetables like carrot sweet potatos.

Peeled by dipping them in 1-2 % boiling caustic soda soln

for 30sec. to 2 min.

5. Flame Peeling:

It is used only for garlic and onion which have a papery

outer covering.

This is just burn off.


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Cutting:

Pieces of the size required for canning are cut. Seed, stone and core areremoved.

Blanching:

It is also known as scalding,

parboiling or precooking.

Cooking at 180oF to 200o F and

immediately cooled by

immersion in cold water.

How canning protects food:

Essentially, food that has been washed and prepared is sealed in a tin-coated steel can.The can is then subjected to heat to raise the temperature to a predetermined level for a set period

to kill food spoilage organisms and, if present in the food, those pathogens which cause food

poisoning.Chemical preservatives are not needed in the food canning process. The minimum temperatures

and timings for safe processing have been established by scientific methods and are used by all

canning companies.

Canning Problems

Loss of liquid Imperfect seal Product dark at top of jar Cloudy liquid Undesirable color changes


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Sediment in jars Spoilage Floating Cloudy sediment in bottom of jar Separate of juice Poor flavor

Equipments used in canning process:

Home Canning Equipment

Glass jar:

These jars are available in many different shapes and sizes. They usually contain a flat brass lidand ring. The brass lid is fitted with a rubber gasket or washer on the underside of the rim. One

of the earliest glass jars developed for food preservation are the mason jars. These jars were

invented in 1850 by John L Mason and they are still used for home canning. Mason jars are

made of soda-lime glass and you can notice a dimpled shape on the lid, which actually can becompared with an indicator. It indicates whether a jar is properly sealed, as a sound is produced

on pressing that area, if the jars are not sealed properly. Cans or metal containers can also be

used for home canning, however they cannot be reused like the glass jars. They are also

expensive and may require some special sealing equipment.

LidsThe old, rusted or deformed jar lids should not be reused for home canning, as they cannot seal

the jars properly. Instead, purchase a new lid for your jar.

Though a variety of jar lids for home canning are available in the market, you need to choose one

that can properly seal the jar. Many of the lids are found in two pieces, a small cap and a band or

screw.

The small cap is designed in such a way that it can fit into the jar rim, while the band or screw

holds the cap in place. Get the right sized cap for your jar and test if it can steal your jar

completely

Water Bath CannerThe home canning process also involves the use of a water bath canner, which is a home canning

machine used for processing jellies, fruits and other high acid foods. This equipment usually

comes with a canning rack, where the filled jars are placed before inserting inside the water bath

canner.

This facilitates both insertion and removal of the jars from the water bath canner. A canning rack

keeps the jars in place and also prevents their contact with the bottom of the canner. For


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purchasing a water bath canner, first decide on their size, as the jars have to be completely

accommodated by the water bath canner.

The water bath canner should be able to accommodate all the jars in such a way that the water

level remains at least one or two inches above the top of the jars.

Pressure Canner:

While a water bath canner is suitable for high acid foods, a pressure canner is ideal for foods that

contain low acid levels and also for canning meat.

This is because the temperature required for killing bacteria in low-acid foods is usually higher

than the one that can be achieved with a water bath canner.

Pressure canners are generally made of aluminum or stainless steel with twitch-on lids fitted with

the gaskets. The jars or bottles are not required to be completely immersed in water inside thepressure canner.

Jar Lifter and Non-Metallic Spatula:

Jar lifters are the tool used for lifting processed jars from inside the water bath canner or pressure

canner. This tool enables safe insertion as well as removal of the hot jars by providing a securegrip, while a non-metallic spatula is used to release the air bubbles from inside the filled jars.

Though home canning is an easy process used for preserving foods for a considerable period, it

needs to be done with appropriate care. Sealing the jars or cans can be termed as the most

important part of home canning, which if not done properly, can even lead to food poisoning.The appropriate use of the various home canning equipment would help avoid such conditions.

Bottle & Jar Packaging Equipment:

Temperature Control fully automatic water Bath

The programmable controllers offer the highest level of performance,flexibility, & control for the most demanding applications. Temperature-viscosity profiling testscan run independently without operator involvement.

Enhanced manual Digital Controllers have easy-to-use controls. Just dial in your set-point andpush a button, you're done!
http://www.buzzle.com/articles/food-poisoning/http://www.buzzle.com/articles/food-poisoning/


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Retort:

This period is essential in order to cook the product thoroughly, thereby destroyingany organisms that could later spoil it. These organisms, called spores, are able to withstandSeveral hours of atmospheric boiling water temperature, but are destroyed in a short time at a

temperature of 116 to 121C (240 to 250F).

Retort operation:

The correct temperature and the duration of the cook period are equally important in achieving

the desired objectives. Overcooking not only increases costs, it also causes loss of taste or

appearance of the finished product.

The time from when the steam is turned on to when the process temperature is reached is thecome-up time. Once this has finished the process begins. Process time is from the end of the

come-up time to the commencement of cooling.Duringcoolingthe steam is turned off and water is added to the retort immediately to prevent

overcooking. There are two methods of cooling; for small cans at temperatures less than 116C

atmospheric cooling may be used.

For cans with a diameter greater than 6cm or processed at temperatures greater, than 116Cpressure cooling is used. In pressure cooling the pressure around the containers is maintained

By compressed air during the addition of water. The water addition causes the steam to condense

and the pressure outside the package drops suddenly. As the internal pressure inside the

container does not drop until the contents cool, seam distortion may occur if the external pressure

is not kept high.At this stage can seams are very fragile and cans must be handled very carefully. All water used

for cooling heat processed foods must be chlorinated to disinfect it in case water is sucked intothe can during cooling.

Still Retort with OverpressurePressure in excess of normal pressure at a given temperature May now have air introduced to

retort during processing as well as cooling Purpose


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Maintain container integrity Maintain integrity.Internal pressure developed during processing is

greater than pure steam pressure is pressure

Continuous Retorts

Still and agitating retorts may be batch or continuous. Continuous retorts have four sections:can warmer

pressure section

pressure cooler

atmospheric cooler

These retorts have self sealing valves which maintain pressure and tolerate temperatures up to

143C.

AGITATING RETORTS

Some retorts agitate the cans during processing in order to increase the rate of heat penetration

into the cans. Agitation may either be axial or end over end. Agitation is useful for productswhich are too viscous to heat or cool by natural convection. By using agitation, the process time

may be reduced by up to 80%. Mixing is largely due to the movement of the headspace duringagitation and to be effective there must be a sufficiently large headspace inside the can. A small

headspace may lead to under processing.

Agitating Retorts Discontinuous Container Handling

Batch container handling

Continuous product agitationVariety of retort types

End-over-end or side-over-side

Description of Retort

Containers held in place

Rotating framework holds basketsVariable rotation speed

Wide range of containers

Custom racking systemVarious processing methods

Exhausting

Exhausting aims to remove air from the package before closure. Correct exhausting will:

Remove all gases from the headspace which will minimisestrains on seams during retorting.

Remove oxygen, otherwise ether corrosion, oxidation and discoloration will result.

Give a vacuum on cooling to give space for the gases which are formed on storage.


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Three exhausting methods:

1. HEAT EXHAUSTContents are heated before sealing. This is ideal for products containing lots of trapped air. Final

temperature depends on closing temperature and headspace.

2. STEAM INJECTIONThis flushes the headspace out with a jet of steam just before closing. This method is more

effective where products are packed in hot brines and syrups and where a large headspace exists.

3. MECHANICAL EXHAUSTUses a vacuum pump to remove air from the package. Food is filled at low temperatures. This

method is useful for foods which trap a great deal of air.

A vacuum gauge may be used on a cooled can to determine the vacuum of a can. The minimumacceptable pressure is about -23kPa. Desirable vacuum will vary for different products Retort

Operation Containers are loaded into baskets.

References:

1. Fruit and vegetable Preservation R.P. Srivastava & Sanjeev Kumar

2. http://www.eolss.net/Eolss-sampleAllchapter.aspx

3. http://ohioline.osu.edu

4. http://www.utextension.utk.edu

5. http://www.utextension.utk.edu/fcs

6. http://www.foodsci.uoguelph.ca/dairyedu/pasteurization.html

7. http://www.vhall.nl/International/Chinese/Downloads/HeatPreservation.pdf
http://ohioline.osu.edu/http://www.utextension.utk.edu/http://www.utextension.utk.edu/http://ohioline.osu.edu/

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