Classification And Discussion Of Esterification

1017 Words Apr 16th, 2016 5 Pages
Results and discussion
Esterification extent:
The color reaction using hydroxylamine hydrochloride was used with modification to quantify the extent of esterification of proteins and the results showed that the highest level of esterification was recorded for esterified cowpea protein isolate (82%) followed by esterified common bean protein isolate (79%).
Functional properties of native and modified proteins:
PH-solubility profile:
The pH-solubility curves of native and esterified cowpea protein are shown in Fig.1. The solubility profile of native cowpea indicate that protein solubility reduced as the pH increased from 2 to 4, which corresponding to its isoelectric point, after which subsequent increases in pH increased protein solubility progressively. The minimum solubility for native cowpea (10 %) was at pH 4 which corresponds to its isoelectric point ( IP).The highest protein solubility (80%) was observed at pH 10. Esterification increased protein solubility in the acidic pH range from 2 to 5. Increasing pH more than 5 reduced the solubility and giving a minimum value (9 %) at pH 6. Methylated cowpea protein was more soluble in the acidic range of pH and less soluble in the alkaline range of pH as compared to unmodified protein. On the other hand The solubility profile of native common bean indicate that protein solubility reduced as the pH increased from 2 to 5, which corresponding to its isoelectric point, after which subsequent increases in pH increased protein…
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