Tuesday, May 10, 2022

Apple pectin extraction

Pectin is a family of complex variable polysaccharides extracted from the primary cell wall of higher plants. Apple pectin is a hydrophilic colloid that is widely used in the processing of fruit drinks, jams, ice creams, jelly and many confectionery products as a food processing ingredient.

Pectin also being used in pharmaceutical preparation such as medical formulations for stabilizing the suspensions.

Pectin in apple pomace is mainly present in the form of protopectin, an acid soluble polysaccharide. The conventional juice extraction process removes 75 % of fresh weight as juice and 25 % remaining portion is called as pomace. Apple pomace is the by-product left after extraction of apple juice, which is a major processing waste in the apple processing industry.

The most commonly used method for extracting pectin from plant tissue is by heating the plant sample in acidified water.

Traditionally acid solutions are used to extract pectin from plant tissues. The acids employed can be strong acids like mineral acids (hydrochloric acid, sulphuric acid, nitric acid) or weak food grade acids (citric acid). The addition of extra chelating agents such as EDTA to the extraction mixture helps in easy release of pectin from cell wall.

The extraction is a multistage physicochemical phenomenon which involves the acid solubilization of the pectic materials under different pH, temperature and duration conditions generally in the range of 1.3-3.0, 60-100°C and 20-360 minutes respectively.

The solvent precipitate mixture is then mixed till the pectin floats and removed by using cheese cloth followed by drying.

Apple pomace is reported to contain about 18-19 % pectin on moisture free basis and 13.3 % on dry weight basis.
Apple pectin extraction

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