26/08/2023
Get to know the Jam making process both at home and factory level. Contact Titukulane food solutions Inc for affordable consulting services in food processing across the country.
Jam making is a highly accurate science. The ability of a jam to set depends on a delicate balance of three factors: sugars, acidity and pectin.
Pectin is a polysaccharide (a long sugar chain molecule) that acts as a natural gelling agent. It is found in fruits, particularly in the peels and cores. Boiling jam releases pectins from the fruits cell walls. At around 104°C the long pectin chains can bind to each other via intermolecular interactions to form a gel network. On cooling this network traps the liquid, causing it to set.
Different fruits contain different amounts of pectin. For example, strawberries and cherries have low levels and blackcurrant, citrus fruit and apples have very high levels. Fruits that are lower in pectin require more pectin to be added either in the form of a commercial pectin (made form citrus fruit peel and seeds) or by the addition of fruits higher in pectin.
A pH of approximately 2.5-3.5 is required for pectin to form a gel. This acidic pH reduces electrostatic repulsive forces between the pectin chains. Fruits can provide acidity, but often extra acids are added (e.g., lemon juice) to ensure the pH is in the correct range.
Sugar level is also very important. Most recipes for jam have a roughly equal ratio of sugar and fruit. Sugar boosts the gel-forming capability of the jam by drawing water away from the pectin. As sugar binds with the water, it also means there is no longer enough water available in the jam to support microbial growth.