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Ingredients used in Home Food Preservation

Water accounts for over 90% of most foods. When water is a recipe ingredient, its composition can determine the quality of the final product.

For safety reasons, use only water that you know is safe to drink. The quality of canned foods can be affected by the amount of minerals in water. If hard water is used, high levels of calcium or magnesium can lead to the formation of white precipitate that clouds the brine and eventually settles to the bottom of the jar. This is especially true for low acid foods such as canned green beans. Other minerals, such as iron, can darken light colored foods or add an unpleasant flavor. If minerals in hard water are a problem, consider using filtered bottled water or passing water through one of the commercially available water treatment units that attach to the faucet.

Salt and salt substitutes

Salt is generally added to foods to enhance their flavor. Salt can be omitted for canning tomatoes, vegetables, meats, poultry, and seafood since the amount added does not contribute to the safety of the food. However, in fermented sauerkraut and brined pickles, salt not only provides characteristic flavor but also is vital to safety since it favors the growth of desirable bacteria while inhibiting the growth of others. Therefore, do not attempt to make sauerkraut or fermented pickles by cutting back on the salt required.

Table salt is safe to use for canning. However, it usually contains anti-caking additives that may make the brine cloudy or produce sediment at the bottom of the jar. Iodized salt is not recommended for fermenting pickles and sauerkraut, or for canning because it may cause them to darken, discolor, or be spotty. It will also cause unusual colors to form in some vegetables. For example—cauliflower will sometimes turn pink or purple.

Canning salt or pickling salt is pure salt—no additives. These are the best choice for canning, pickling, and sauerkraut.

Kosher salt is a coarse, flaked, pure salt that can also be used in canning. Since flaked salt may vary in density, is not recommended for making pickled and fermented foods where salt concentration is a critical factor for microbial growth.

Sea salt is evaporated sea water and contains various minerals. It is safe to eat but minerals in the salt may cause canned foods to discolor.

Rock salt, ice cream salt, and solar salt are used to melt ice, freeze homemade ice cream, and to soften water. Since they are not considered suitable for human consumption, do not use them for home food preservation.

Salt substitutes contain chemicals that provide a salty flavor but contain little or no sodium. Most salt substitutes contain potassium chloride. Some people think the potassium chloride has a metallic taste. One brand adds L-lysine to mask the metallic flavor. Do not substitute potassium chloride for sodium chloride in fermentation recipes. One way to lower the sodium content of sauerkraut or pickles is to rinse the product with water just before heating and serving. But never do this before canning. Lowering the salt content of fermented products before canning will lower the acid content (raise the pH) and possibly render the product unsafe to eat or quick to spoil.

Sugars and non-nutritive sweeteners

Table sugar (sucrose) is the typical white granulated product we use to sweeten foods. Brown sugar is refined white sugar with molasses mixed in and, although the flavor differs somewhat, it has about the same sweetness value as white sugar on a volume basis. Powdered sugar is finely ground sucrose combined with a small amount of cornstarch to prevent caking. This starch makes it unsuitable for canning because it may cause the brine to become cloudy. In addition to its sweetening effect, sugar serves as a preserving agent and aids in gelling of jams and jellies.

Corn syrup is a viscous mixture of glucose, fructose, and polysaccharides. It is difficult to convert a volume of sugar into an equivalent amount of corn syrup at the same sweetness level. We, therefore, can only recommend using corn syrup for home food preservation if a recipe specifically indicates how much to use.

Honey is a natural product in which the primary sugar is fructose. It is safe to use as sweetener for canning or freezing. However, the flavor of the honey sweetened foods may be noticeably different than expected. You may wish to make small quantities first to determine if you like them.

Splenda® is a commercially formulated mixture of sucralose, starch, and dextrose sugar. Although sucralose is a chemically modified form of sucrose with no nutritive value (0 calories), the bulking agents added do contribute some energy value and the product contains about 12% of the calories of an equal volume of table sugar. Unlike other non-nutritive sugar substitutes, Splenda® is heat stable and so can be used in canned foods. Some people do notice an aftertaste flavor that may increase with storage time. Although Splenda® will provide sweetness, it will not provide the firmness to canned fruits that sugar does. Products canned with Splenda® will therefore be similar in texture to those canned in water. The Splenda® website has recipes for preparing shelf stable jams and jellies.

Stevia is stable to heat and could be used for canning fruit and other products where sugar is not critical to food safety or texture. Rebaudioside A, the active ingredient in Stevia, is 300 times sweeter than sugar. It has been listed as Generally Recognized as Safe (GRAS) by the Food and Drug Administration (FDA) and therefore is exempt from food additive regulations. Truvia is a Stevia-based sugar substitute currently available on the market. According to their web site (ww.truvia.com) the product can be used for baking. We have no reliable information on its potential for canning and freezing. Green Stevia leaves or leaf powders are available but there sweetening effects might not be consistent.

Aspartame is not recommended for canning since its sweetening properties are greatly reduce within a few weeks. Saccharin is more heat stable and can be used for jellies and jams. Both are suitable for freezing. For both canning and freezing, use specific recipes, such as those available from the National Center for Home Food Preservation to make sure the proper sweetening agent can be used for the intended purpose and for proper amounts to add. Both can also be added just before serving.

Acidulents

Acids naturally present or added to foods are an important part of the preservation process. Never change the amount of acid, dilute with water, or substitute acid sources unless the recipe specifically allows you to do so.

Vinegar is naturally obtained by sequential fermentation of sugar to alcohol and then to acetic acid. Cider vinegar is derived from apple juice while white vinegar is made from pure grain alcohol. For home food preservation purposes, use vinegars that are labeled as 5 percent acidity (50 grain) since they produce consistent results. White vinegar is usually preferred when light color is desirable, as is the case with fruits and cauliflower. Do not use homemade vinegar or vinegar of unknown acidity in pickling. Do not dilute the vinegar unless the recipe specifies this since you will be diluting the preservative effect. If a less sour product is preferred, add sugar rather than decrease the vinegar.

Lemon juice is another natural acidulent commonly used in home food preservation. T o assure safe acidity in whole, crushed, or juiced tomatoes, add 2 tablespoons of bottled lemon juice per quart of tomatoes or 1 tablespoon per pint. An alternative to lemon juice for acidifying tomatoes is citric acid (see below)

Citric acid is usually sold as a white crystalline powder. It can safety be used to acidify foods if used correctly. To acidify the canned tomatoes described above, citric acid may be used instead of lemon juice. Add 1⁄2 teaspoon per quart or 1⁄4 teaspoon per pint. Citric acid is also used to preserve the color of fresh cut fruit or as a pre-treatment for frozen and dried fruit (see color preservative section).

Aspirin, also known as acetylsalicylic acid, should only be used for its intended purpose - Never to acidify foods. Some people have a bad reaction to aspirin and its acidification properties vary depending on its strength.

Color enhancers and colorants

Citric acid is used to preserve the color of fresh cut fruit or as a pre-treatment for frozen and dried fruit. It can be used either alone or mixed with other substances, such as ascorbic acid, erythorbic acid, N-acetylcysteine, glutathione, and EDTA. Most people find it more convenient to use commercial prepared anti-oxidant formulations such as Fruit-Fresh®, which contains a mixture of citric and ascorbic acids as active ingredients.

Ascorbic acid, also known as Vitamin C, is used as an anti-oxidant to keep fruit from darkening. Pure crystals may be obtained at supermarkets and drug stores. Soak fruit immediately after cutting for 10 minutes in a solution prepared with 1 teaspoon of pure ascorbic acid dissolved in one gallon of cold water. Crushed Vitamin C tablets can also be used. Six 500 milligram tablets equal 1 teaspoon of ascorbic acid. Erythorbic acid, also known as iso-ascorbic acid, is chemically identical to ascorbic acid, but because it is structurally different, has no Vitamin C activity. It does have similar anti-oxidant properties though and can be used the same way ascorbic acid is used to retain color.

Sulfites are sulfur containing compounds have been used for centuries to prevent discoloration and reduce spoilage during the preparation, dehydration, storage, and distribution of many foods. However, in recent years, sulfites have been implicated as initiators of asthmatic reactions in some people, especially those with asthma. As a result, the Food and Drug Administration (FDA) has banned the use of sulfites on fresh fruits and vegetables for sale or served raw to consumers. They are still used as an antimicrobial agent and to help preserve the color of some dried fruit products. But because of the health considerations involved, we recommend the use of alternative methods for color preservation.

Food colors are available in both synthetic and natural forms. Although not necessary if good quality ingredients are used, there are several food grade food dyes available that are safe to use according to label directions. For example, red food coloring is an optional ingredient for canned cherry pie filling. Some highly colored fruits or vegetables can act as a natural color source. An example is beet juice which is often used to impart a red color to refrigerator pickled eggs.

Texture enhancers and thickening agents

Pickling lime is a safe product that if used correctly can be used to improve the texture of pickles. But it is not necessary if good quality ingredients are used. Food-grade lime is used as a lime-water solution for soaking fresh cucumbers 12 to 24 hours before pickling. Excess lime absorbed by the cucumbers must be removed to make safe pickles. To remove excess lime, drain the lime-water solution, rinse, and then re-soak the cucumbers in fresh water for 1 hour. Repeat the rinsing and soaking steps two more times. An alternative way to improve pickle firmness is to pack room temperature cucumbers in the jar and pour hot (165 - 180°F) liquid over the product leaving the appropriate headspace. Use a candy or jelly thermometer to check the liquid temperature. Then seal and process in a hot water bath at 180oF for 30 minutes. The rationale for this method apparently is that a moderate pre-warming treatment prior to processing activates the enzyme pectin methylesterase which is known to improve post processing firmness by increasing the number of calcium bonding sites on cell wall pectin molecules.

Pickle Crisp” is a food grade calcium chloride product from Ball. It provides the calcium to help firm pectin, but does not have the hydroxide component that can lower the acidity of pickled foods. Follow the manufacturer’s directions. Do not calcium chloride products that are not specifically labeled as food grade, since they may contain other chemicals that are not safe to eat.

Alum sold as a pickling ingredient may be safely used to make fermented cucumbers crispier. But it is unnecessary if good quality cucumbers are used and tested recipes are followed. Alum does not improve the firmness of quick-process pickles.

Starch is a common thickener for many food products. Since the viscosity (thickness) of food during canning affects the amount of heat that penetrates into jars during processing, use only the exact type and amount of starch specified in the recipe. Do not modify recipes for soups by adding starch thickeners since this may result in under-processing. ClearJel® is recommended in the USDA Canning Guide for canning pie fillings because it remains thin during processing to allow heat to penetrate into the jar and then thickens upon cooling. It also does not breakdown at high temperatures, which would result in a runny consistency of the final product. However, ClearJel® is not recommended for frozen sauces since it tends to weep during thawing. Instant ClearJel® thickens without cooking and thus is not suitable for canned pie fillings. However, because it is freeze/thaw stable, it is a good option for preparing a pie filling just before pouring on top of a crust and then freezing. Thermflo® is an acceptable alternative for canning since it is also stable during heating and exhibits about the same viscosity during heating as ClearJel®. It has the added advantage of holding up well during freeze/thawing.

Pectins are naturally occurring substances in fruits that form a gel if they are in the right combination with acid and sugar. Apples, crab apples, gooseberries, and some plums and grapes usually contain enough natural pectin to form a gel. Other fruits, such as strawberries, cherries, and blueberries, contain little pectin and must be combined with other fruits high in pectin or with commercial pectin extracts to obtain gels. Modified pectins, called low-methoxyl pectin, are available that will form gels with little or no sugar. Calcium is usually part of the formulation since it is necessary to aid in gel formation. Low sugar jams and jellies made with modified pectins should be processed longer in a boiling-water canner since the preservative effect of sugar is reduced. There are many modified pectin products available. To obtain best results, follow the instructions provided exactly as written.

Gelatin is an animal protein that forms a gel under refrigerated conditions. Gelatin is not heat stable and therefore is not appropriate for canned foods. However, it may be used to thicken refrigerated low sugar jams and jelly recipes.

Tapioca is another option for thickening pie fillings. Tapioca granules are small, starchy grains that don’t dissolve completely when cooked, so pies thickened with them have tiny gelatinous balls. (Instant tapioca or tapioca starch would eliminate the balls, because it is finely ground). This starch thickens at a lower temperature and stays stable when frozen. To use in a pie filling, when mixed with the other ingredients, let it sit for 5 minutes to soak up some of the liquid. Tapioca is not recommended for canning pie fillings or other canned foods.

Miscellaneous Ingredients

Oils are pressed from several types of plants including corn, sunflower, safflower, canola, olives, walnuts, and hazelnuts. A few teaspoons of aromatic oils may be added to canning recipes with no affect on the safety of the process. However, adding more than this to an already approved recipe may be hazardous since penetration of heat into the product may be affected.

Spices and herbs are aromatic dried leaves or other plant parts used to flavor food. Because of their intense flavor, dried spices and herbs are used in small amounts that do not affect the safety of recipes. Pre-mixed spice mixes are available for specific products, such as for salsa or for pickled vegetables and are safe to use if package instructions are followed. A few sprigs of fresh herbs can also be added to canning recipes with no adverse effects. But if a fresh herb is the main ingredient of the product, such as for basil pesto, it must be processed as a low acid food. We do not have any tested recipes for pesto sauces and encourage people to freeze this product instead.

Water glass, chemically known as sodium silicate, has long been used to preserve eggs. We cannot recommend the use of water glass since the safety of products preserved using this ingredient has not been scientifically evaluated.

Reviewed May 2011

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Ingredients used in Home Food Preservation

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Luke LaBorde
  • Associate Professor of Food Science - Plant Based Products.
Email:
Phone: 814-863-2298