Mechanism of gel formation by low methoxyl pectins.

Padival, R. A. and Ranganna, S. and Manjrekar, S. P. (1979) Mechanism of gel formation by low methoxyl pectins. Journal of Food Technology, 14 (3). 277-287, 9 ref..

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Abstract

For stable gel formation, low methoxyl pectin (LMP) should contain greater than50% of the galacturonic acid (GA) in the free carboxylic form. This is achieved by precipitating acid and NaOH-deesterified LMP at pH 0.5, 1.5 or 3.0, and ammonia-deesterified LMP at pH 0.5 or 1.5, but not at pH 4.5. With such LMP, depending on the concn. of Ca added and methoxyl content, the sol becomes gel. The changes are classified into 5 regions: sol, soft gel, good gel, brittle gel and coagulated gel. The mechanism of gel formation by LMP involves reaction of 40-50% of the GA present in the free carboxylic form with Ca which causes the precipitation of 75-90% of the total LMP, including the entire galacturonic acid units present in the esterified form. The LMP so precipitated holds 50-60 g water/g and forms a stable gel. Higher concn. of Ca than the optimum increase the reactivity to 80-90% which results in strong cross linkages, incipient precipitation of LMP and loss of gel state.

Item Type:	Article
Uncontrolled Keywords:	GELS-; pectins, gels formation by methoxyl-low; PECTIC-SUBSTANCES; gels formation by methoxyl-low pectins
Subjects:	600 Technology > 08 Food technology > 24 Fruits
Divisions:	Fruit and Vegetable Technology
Depositing User:	Food Sci. & Technol. Information Services
Date Deposited:	24 May 2016 12:08
Last Modified:	24 May 2016 12:08
URI:	http://ir.cftri.res.in/id/eprint/6932

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