Extraction of pectin from some local fruits and its use in jam processing

Azhari S. Abdelwahab, Abdel Moneim E. Sulieman, Sirelkhatim B. El-Hardallou

Abstract


In the present study, pectin was extracted from orange, grapefruit and guava fruits and used in jam processing. The percentages of pectin extracted from orange, grapefruit and guava powder were 28%, 26.4% and 2.8%, respectively. Jam made using pectin extracted from grapefruit (GrPJ), orange (OPJ) and guava (GuPJ) contained 66%, 67% and 67% total soluble solids, respectively. The reducing sugar contents of GrPJ, OPJ and GuPJ were 4.7%, 5%, and 4.1%, respectively, while the total sugar contents were 8.7%, 8.5% and 8.4%, respectively. The pH values of GrPJ, OPJ and GuPJ were 3.5, 3.4 and 3.6, respectively. Moisture contents of GrPJ, OPJ and GuPJ were 53.7%, 45.8% and 47.4%, respectively, and the ash contents were 0.23%, 0.18%, and 0.21%, respectively.  The contents of sodium were 36, 34 and 35 mg/100g in OPJ, GrPJ and GuPJ, respectively, while the contents of potassium were 60, 68 and 69 mg/100 g, respectively. The contents of calcium were 80, 79 and 78 mg/100 g, respectively. The content of vitamin C of OPJ, GrPJ and GuPJ were 0.01, 0.02, and 0.02 mg/100g, respectively. Microbial analysis revealed that all jam samples were devoid of coliforms, staphylococci, yeasts and moulds. The sensory analysis indicated that all types of jams were accepted by panelists who preferred them in the order of jam made using commercial pectin followed by jam made using pectin extracted from orange, grapefruit and guava. Most panelists preferred the jam made using commercial pectin due to its appealing color and appearance.


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