Jam And Jelly Lab Report

Complete the Chemistry of Pectin lab exercise and then answer the following questions.

1. What is the difference between jam, jelly and fruit preserves?

The three points of differentiation are the type of fruit, how it is prepared and the proportion of ingredients.

Jams are made of crushed fruits which are cooked with pectin, sugar [and maybe lemon juice to change the pH and cause the jam to become more solid] until the mixture thickens to spreadable consistency. In the lab, we made jam using 500 ml of each high-pectin fruit ingredient, about 20 ml of lemon juice to balance the flavour and cause the pectin to gel, and 500ml of sugar.

Jellies are clear and gel-like. The fruits are cooked and the juice only is used to make jelly. The juice is boiled with sugar, pectin may be added, then it is allowed to set.

Preserved are crushed cooked fruits stored in one of above, in syrup, water or their own juices. The fruit keeps its shape.

2. What pH range is required for jams to set or gel?

Pectin causes the jelly or jam to set and the bonds that it creates resulting in a gel are strongest at a pH of 2-8 to 3.2 (Herbstreith & Fox n.d.).

3. Why are moulds a problem in jams and jellies?

The air within the jam jar

That may be a mineral acid other enzyme because water alone is insufficient to extract a commercially viable amount of pectin. Once the pectin is ready to be removed, it is separated in a filter or centrifuge, then filtered again to clarify it. The concentrated liquid is mixed with an alcohol to precipitate the pectin. Once the pectin is separated it is washed with alcohol to remove impurities and is then dried. If required, ammonia is added to made amidated pectin (converted into an amide). Amidated pectin is able to solidify when it cools. The dry solid is ground and tested and, finally, it may be blended with other gelling powders (IPPA: International Pectin Producers Association