Canned White Potatoes

Periods: 3

  1. Planning
  2. Processing
  3. Evaluation

Objectives:

1. To familiarize the student with the principles of canned vegetables.

2. To familiarize the student with the unit operations involved in the proces.5ing of canned vegetables.

3. To enable the student to distinguish between acceptable and unacceptable canned vegetables and to identify parameters upon which the distinction is made.

Background:

Preservation of fruits and vegetables by canning dates back to the work of Apert in France in the 19th century. Potatoes are considered to be a low acid food, and canned potatoes are covered by USDA standards and FDA standards of identity. Potatoes are canned in two styles: (a) covered with a salt brine or (b) covered with a starch sauce. Potatoes can be canned whole, diced or sliced, with diced potatoes being commonly used for the preparation of soup.

For potatoes in brine, the potatoes are peeled and filled in cans with plain bodies and empanelled ends. Commonly a hot brine containing 10-20 pounds of salt per 100 gallons of water added. If hot water is used, the salt may be added either in tablet form or in such amount that the resulting brine in the can has a salt content of 1.5 to 2.0%.

The physical properties of the canned potato are dependent upon a number of factors, including:

a. Variety

    1. Specific gravity
    2. Sugar content
    3. processing conditions

Federal Standards of identity permit the addition of up to 100 ppm CaNa2 EDTA to control sloughing. Calcium is not required for tubers of less than 1.075 specific gravity. Salt tablets containing 1.4-1.7% CaNa2 EDTA with and without 20% calcium chloride are commonly used.

The processing times and temperatures in still retorts are dependent upon the can size, initial temperature of the product going into the retort, whether the potatoes are whole, diced or sliced and whether the potatoes are in a brine or starch solution.

 

 

 

 

 

For 303 cans, potatoes in brine at an initial temperature of 140° F, require the following minimum times for different retort temperatures:

Form of potato: 240°F 245°F 250°F

Sliced 39 min 28 min 22 min

Whole 31 min 24 min 20 min

Procedure:

White potatoes can be canned in brine in several styles :

1. whole

2. diced

3. sliced

Following instructions given by the instructor, select, prepare and process white potatoes into a canned product. Be sure to collect and record all data during processing. This includes: potato variety, specific gravity , brine composition, and processing times and temperatures.

Evaluation

  1. Determine the specific gravity of each batch of potato chips, both raw and finished product.
  2. Determine the vacuum in the can
  3. Determine the headspace in the can after processing.
  4. Evaluate the cans for vacuum and proper sealing.
  5. Determine the drained weight of the potatoes.
  6. Evaluate for defects.
  7. Using a sensory panel, determine the texture and flavor acceptability of each batch of potatoes.
  8. Compare you potatoes with several brands of canned potatoes available in commercial channels.

 

REFERENCES :

A Complete Course in Canning Book 2. Processing Procedures for Canned Food Products. The Canning Trade. Baltimore MD. 1981.

Potato processing / edited by William F.Talburt and Ora Smith. Westport, Conn. : AVI Pub. Co.,1987