Dynamic rheology and microstructure of starch gels affected by triticale genomic composition and developing stage

Abstract

Starches of developing triticale grains, differing in genome composition (complete AABBRR or substituted AABBDR), were evaluated in terms of starch granule distribution, dynamic rheological behaviour and microstructural characteristics on several days after anthesis. The starch granules were of an oblate spheroid shape for A-granules, and of a spherical shape for B-granules. However, those obtained from the complete triticale showed a larger diameter size. An X-ray diffraction analysis revealed the common A-type pattern of cereal starches from early development stages. A dynamic rheological analysis showed that the storage and loss moduli reached maximum levels in the temperature range of 71-86ºC and dropped at around 90ºC. Starches from the complete triticale showed lower phase transition temperatures, compared to those obtained from the substituted genotype (56.1±0.3 and 60.3±0.8°C, respectively). Scanning electron microscopy showed that the gels made with the starch of complete triticales were of a less dense sponge-like structure.