University of Khartoum

The Yield and Characteristics of Gudeim (Grewia Tenax) Juice

The Yield and Characteristics of Gudeim (Grewia Tenax) Juice

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Title: The Yield and Characteristics of Gudeim (Grewia Tenax) Juice
Author: Alrikain, Abdalla Elsheikh Mohamed Salih
Abstract: A 2×2×4 factorial experiment in a completely randomize design was utilized to study the effects of extraction temperature [cold (room) and hot (65ºC)], extraction methods (hand pressing and blending) and 4 types of packages (GB, PB, PC and TT carton) on yield and physicochemical, microbiological and storage life of Gudeim (Grewia Tenax) juice stored refrigerated for up to 28 days. Irrespective of the extraction temperature or extraction method, a 1:4 ratio (Gudeim fruit: water) gave a Juice yield of about 76 %. Fresh Gudeim juice has a pH around 4.00, an acid content of 0.25 – 0.29 %, total soluble solids of 9.36 ºBrix , total solids of 10.15% , viscosity of 11.4 sec. and specific gravity of 1.055 . The chemical composition revealed that glucose and fructose are the two main sugars in Gudeim fruit and juice with fructose being the predominant sugar. Cold extracted Gudeim juice contained substantial amount of iron ( 6.73 ppm) and potassium (1.42 g/kg) however hot extraction resulted in a substantial decrease in mineral contents of Gudeim juice. The chemical composition of Gudeim fruit resembles that of most fruits except that it has higher protein and ash contents. The physicochemical properties of hand pressed juice particularly ºBrix and pH were significantly higher than those of blended juice but had significantly lower acidity. Effect of storage period on total soluble solids was noticeable after 14 days while pH and acidity decreased and increased respectively with the increase in storage period. Package type had only slight effects on the physicochemical properties of Gudeim juice. All Hunter color values showed a significant change with storage period. Hunter L* value of cold extracted juice was higher than that of hot extracted juice. Initially cold extracted juice had higher total plate count (TPC) and Coliform however hot extracted juice had higher yeast and moulds count, the trend continued throughout the storage period tested. The storage life of semi-clarified unpasteurized Gudeim juice was about 14 days.
Description: August 2004107 Pages
URI: http://khartoumspace.uofk.edu/handle/123456789/10663
Date: 2015-05-12


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