Waxy wheats: Origin, properties, and prospects

Abstract

Starch amylose is synthesized through the activity of the granule-bound starch synthase (GBSS). In wheat ( Triticum aestivum L.), there are three structural genes encoding isoforms of GBSS. Naturally occurring mutations (null alleles) resulting in the loss of one or more GBSS isoforms have recently been identified. The presence of one or two GBSS null alleles results in the production of starch with reduced amylose content. Reduced amylose wheats have been termed ‘partial waxy’. Wheats with three GBSS null alleles produce essentially amylose-free, or waxy, starch. Partial waxy wheats are sources of flours with optimal quality characteristics in certain Asian wet noodle products. In addition, partial waxy wheats are essential to the development of waxy wheats with acceptable agronomic performance. Biochemical features of starch from waxy wheats are similar to those of waxy maize. Waxy wheats may find application in the production of modified food starches, as blending wheats for the formulation of superior noodle flours, and as a means to manipulate amylose contents in substrates for extrusion. Flour from waxy wheats may also be used to extend the shelf-life of baked goods, without a concomitant dilution of wheat gluten. Finally, waxy wheat may increase profitability to gluten manufacturers by providing a co-product with added value.