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Low methoxyl pectins from lime peel
Author(s) -
PADIVAL RAJNI A.,
RANGANNA S.,
MANJREKAR S. P.
Publication year - 1979
Publication title -
international journal of food science and technology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.831
H-Index - 96
eISSN - 1365-2621
pISSN - 0950-5423
DOI - 10.1111/j.1365-2621.1979.tb00878.x
Subject(s) - pectin , saponification , chemistry , lime , sodium hydroxide , calcium hydroxide , ammonia , precipitation , alkali metal , chromatography , nuclear chemistry , food science , organic chemistry , meteorology , metallurgy , materials science , physics
Summary To prepare low methoxyl pectin (LMP) from lime peel, acid deesterification at pH 0.5 for 9 hr at 60°C and for 5 hr at 70°C; sodium hydroxide deesterification at 5°C and at pH 10.5 with continuous addition of alkali for 1–2 hr; and ammonia deesterification at 25°C and at pH 10.5 for 2–3 hr or at pH 11.7 for 1–2 hr were suitable. Such LMP had ∼4.5% methoxyl groups and a molecular weight of 40 000–70 000. Precipitation at pH 0.5 to 1.5 after saponification resulted in LMP having good gelling characteristics; precipitation at pH 4.5, as recommended hitherto, impaired the gelling property. Saponification titre values of the pectin being deesterified and a rapid gel test, based on the sensitivity of the pectin to the calcium, are described to follow the degree of deesterification. The gel test is also indicative of the gelling property of the pectin.