High-Fiber Ingredients
Pages 73-82
DOI: https://doi.org/10.1094/1891127233.005
ISBN: 1-891127-23-3
Abstract
Topics Covered
- Jams, Jellies, and Preserves
- Icings, Frostings, and Glazes
- Confectionery
- Chocolates
- Soft Confections
- Hard Candies
- Meat, Poultry, Seafood, and Analog Products
- Properties Affected
- Formulation Considerations
- Soups, Sauces, Gravies, and Salad Dressings
- Troubleshooting
Introduction to Chapter
The gelling of fruit-based mixtures produces jams, jellies, and preserves. Jams typically contain fruit pieces or crushed fruit; jellies are made with the juice extracted from the fruit; while preserves are generally made of the crushed, entire fruit. For simplification of this discussion, the term “jam” will be used to refer generally to this product category. The most widely used gelling agent in the production of jam is pectin. While pectin is a high-fiber ingredient, its use at low levels (typically less than 1%) in jam does not significantly contribute to the total dietary fiber (TDF) content of the product. The function of pectin is complex and can depend on many factors such as the type of pectin used, the pH and temperature, and the soluble solids (sugar) and calcium content of the formula.
Pectins of many varieties are available for use in making jam. The two types of pectins traditionally used are high-methoxy pectins and low-methoxy pectins (see Chapter 2). In general, the high-methoxy pectins gel under acidic conditions (pH levels of about 2.9–3.6), with a soluble solids range of about 60–80%. The several types of high-methoxy pectin available vary in their degree of esterification. In general, the greater the pectin's degree of esterification, the faster the setting time. High-methoxy pectins form gels that quickly become stable. Low-methoxy pectins require calcium salts, such as calcium citrate, for gelation. Since low-methoxy pectins require a lower soluble solids concentration (i.e., less dissolved sugars) than high-methoxy pectins, they are often used to make low-sugar jams. Gels formed using low-methoxy pectins are thermally reversible.
Certain processing procedures can aid in producing a high-quality final product. Pectins should be fully dispersed in the formula and should not be subjected to overcooking. The pH of the mixture should also be monitored since jams can exhibit syneresis over time if the pH of the system is too low. Pregelling is undesirable, and buffered pectins are available so that the pectin gels at the appropriate pH upon addition of acid to the formula. Once the formula is fully cooked, the hot, liquid suspension should be transferred immediately into the final product container. If the cooled product is transferred, a grainy product can result.
Other hydrocolloids can be used as the sole gelling agent or in addition to pectin to produce a jam-type product. Gums such as carrageenan and locust bean gum can replace solids and bulk in low-sugar jams and jellies. Gellan gum also can be used since it exhibits good stability in low-pH systems. The gelation characteristics as well as the textural attributes vary depending on the soluble solids content of the formulation.
