Effect of multiple freezing/thawing cycles on the structural and functional properties of waxy rice starch

PLoS One. 2015 May 27;10(5):e0127138. doi: 10.1371/journal.pone.0127138. eCollection 2015.

Abstract

The structural and functional properties of non-gelatinized waxy rice starch were investigated after 1, 3, 7, and 10 freezing/thawing cycles. Freezing caused an increasing damaged starch from 1.36% in native waxy rice starch to 5.77% in 10 freezing/thawing-treated starch (FTS), as evidenced by the cracking surface on starch granules. More dry matter concentration was leached, which was characterized by high amylopectin concentration (4.34 mg/mL). The leaching was accompanied by a decrease in relative crystallinity from 35.19% in native starch to 31.34% in 10 FTS. Freezing treatment also led to significant deviations in the functional characteristics, for instance decreased gelatinization temperature range, enthalpy, and pasting viscosities. The resistant starch content of 10FTS significantly decreased from 58.9% to 19%, whereas the slowly digested starch content greatly increased from 23.8% in native starch to 50.3%. The increase in susceptibility to enzyme hydrolysis may be attributed to porous granular surface, amylopectin leaching, and the decrease in the relative crystallinity caused by freezing water.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Amylopectin / analysis
  • Digestion
  • Food Handling / methods*
  • Freezing*
  • Oryza / chemistry*
  • Starch / chemistry*
  • Starch / metabolism*
  • Temperature
  • Viscosity
  • Waxes / chemistry*

Substances

  • Waxes
  • Starch
  • Amylopectin

Grants and funding

This work was supported by the National "Twelfth Five-Year" Plan for Science & Technology Support of China (Nos. 2012BAD37B06 & 2012BAD37B07), and the graduate student innovation project of Jiangsu province (KYLX_1165).