Comparison of Protein Extraction Solutions for Rice Starch Isolation and Effects of Residual Protein Content on Starch Pasting Properties

Seung Taik Lim, Jong Hyup Lee, Dong Hoon Shin, Hyesook S. Lim

Research output: Contribution to journalArticle

138 Citations (Scopus)

Abstract

Protein extraction solutions such as aqueous solutions of sodium hydroxide (0.1 and 0.2%), sodium lauryl sulfate (SLS, 1.2%) containing sodium sulfite (0.12%), and dodecylbenzene sulfonate (DoBS, 1.2%) containing sodium sulfite (0.12%) were compared in their protein removal efficiencies during isolation of starch from a rice flour (Ilpumbyo, a nonwaxy Korean rice variety). In addition, the pasting properties of the isolated starch was compared. More than 80 % of the flour protein was extracted in 1 h by stirring the dispersion (1:3, w/v) at room temperature. Repeating the extractions (1 or 2h for each step) with fresh solution significantly increased the protein removal efficiency. When the extraction in 0.2 % NaOH was repeated four times (1 h for each step) at 25°C, the residual protein content in the isolated rice starch was 0.9 % (DB), equivalent to 86 % removal of the rice protein. Raising the extraction temperature slightly increased the protein solubility, but starch loss also became significant. Among the solutions, DoBS was most effective in removing rice protein whereas SLS was least. The residual protein content had a critical role in determining the pasting characteristics of the isolated starch, showing a negative correlation to the peak viscosity of the starch paste, but a positive correlation to the pasting temperature.

Original languageEnglish
Pages (from-to)120-125
Number of pages6
JournalStarch/Staerke
Volume51
Issue number4
Publication statusPublished - 1999 Apr 1

ASJC Scopus subject areas

  • Food Science

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