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Functional Properties of Cross-Linked and Hydroxypropylated Waxy Hull-less Barley Starches

¹Department of Applied Microbiology and Food Science, University of Saskatchewan, 51 Campus Drive, Saskatoon, SK, Canada S7N 5A8. ²Corresponding author. Phone: 306/966-5008. Fax: 306/966-8898. E-mail: zhengg@skyfox.usask.ca ³Department of Plant Sciences, University of Saskatchewan.

Waxy hull-less barley (HB) starches containing 0 or 5% amylose were cross-linked with phosphorus oxychloride and the cross-linked starches were hydroxypropylated with propylene oxide. For comparison, waxy corn and potato starches were similarly modified. For all starches, cross-linking inhibited granule swelling and prevented swollen granules from disintegration, resulting in dramatic improvement in pasting properties and tolerance to cooking shear and autoclaving. Cross-linked waxy HB starches were more tolerant to cold storage and cooking shear than cross-linked waxy corn starch. Hydroxypropylation of the cross-linked starches reduced granule crystallinity and gelatinization temperature, and improved granule swelling, paste clarity, and freeze-thaw stability. The double-modified waxy HB starches showed higher cold tolerance than similarly modified waxy corn and potato starches, as judged by freeze-thaw stability and clarity after cold storage. These results indicated that the cross-linked and double-modified waxy HB starches together may have a wide range of food applications. This study indicated that the behavior of granule swelling and disintegration of swollen granules played an important role in governing paste viscosity, clarity, and freeze-thaw stability of waxy HB starches.