Guava and Grapefruit and its Application in Strawberry Jam

^{* 1}.Javeria Hafeez ².Inam-ur-Raheem, ^3.Hafiz Khuram Wasim Aslam, ^4.Azam Shakeel, ^5.Hafiz Arbab Sakandar

National Institute of Food Science and Technology, University of Agriculture, Faisalabad.

* Corresponding Author: khuramwasimfsd@hotmail.com  Cell No: +923457481770

Accepted 04 November 2014

Abstract

The research study was aimed at finding the influence of temperatures (80, 90 and 100ºC) and pH (1.5 and 3.0) on extraction of pectin from guava pomace and grapefruit peel as well as comparing the characteristics of two different pectin and to see which one is more suitable for industrial applications. First of all, guava pomace and grapefruit peel were chemically evaluated for their moisture, ash, protein, fat and fiber content. Pectin, which is a family of complex polysaccharides, was extracted using alcohol precipitation method from guava pomace and grapefruit peel after which it was characterized using both qualitative and quantitative analysis to determine and compare the color, each pectin solubility in cold and hot water, equivalent weight, methoxyl content, anhydrouronic acid content and degree of esterification. The result showed that the colors of the pectin from these 2 sources were brown and light yellow, they were all soluble in hot and cold water, the equivalent weight, the methoxyl content, anhydrouronic acid content and degree of esterification were all higher in the pectin extracted from peels of grapefruit with 4445.4g/mL, 1.55%, 67.35% and 89.23%, respectively. Strawberry jam samples were prepared with two different pectin and analyzed for physicochemical and organoleptic attributes. Physicochemical analysis of jam showed that brix and acidity increased for all treatments during one month storage. The pH reduced for T₁ (from 3.01 to 2.86) and for T₂ (from 2.97 to 2.83). T2 (grapefruit pectin) showed maximum scores for organoleptic characteristics. The overall results showed that the pectin from grapefruit peel was more suitable for industrial use.

Keywords: Guava, Grapefruit, pomace, peel, pectin, characterization, jam, physicochemical, organoleptic