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Measurement of protein in whole plant samples with ninhydrin
Author(s) -
Barbehenn Raymond V
Publication year - 1995
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/jsfa.2740690312
Subject(s) - ninhydrin , hydrolysis , chromatography , hydrolyzed protein , chemistry , acid hydrolysis , amino acid , amino acid analysis , plant protein , biochemistry , food science
Abstract The ninhydrin method has been used widely for measuring amino acids in hydrolysed purified proteins. It is also a useful method of measuring the total amino acid or protein content of hydrolysed plant samples. In this study the conditions used in a modified ninhydrin method were found to incompletely hydrolyse protein. Therefore, standard conditions for protein hydrolysis (6 M HCI at 110† C) were tested. The accuracy of protein measurements using the standard ninhydrin method was evaluated using pure proteins, protein‐carbohydrate standards and plant samples augmented with known amounts of protein. Standard hydrolysis conditions completely hydrolysed proteins, but protein content was overestimated when these conditions were used on whole plant samples and standards containing carbohydrates. This error may be quantified and corrected easily in plant samples, however, by measuring the recovery of protein added to control samples before hydrolysis.