Physicochemical and Molecular Properties of Spelt and Wheat Starches Illuminated with UV Light

Abstract

Scope: Aqueous suspensions of spelt and wheat starch were irradiated with ultraviolet radiation for 5–50 h. The changes in the molecular structure of the starch induced by UV radiation were related to the photodegradation of starch chains and the subsequent recombination of the resulting polysaccharide radicals during prolonged irradiation. Methods and Results: Aqueous suspensions of spelt and wheat starch were irradiated with ultraviolet radiation for 5–50 h. The HPSEC-MALLS-RI method was used to measure the weight-average molecular weights of the starch polysaccharide chains and the distribution of the amylopectin side chains. FTIR spectroscopy of the modified samples and a study of the starch surface morphology were conducted using a scanning electron microscope. However, an increase in both the rate constant of the first stage of hydrolysis (k1) and its final level were demonstrated. The changes in the molecular structure of the starch induced by UV radiation were related to the photodegradation of starch chains and the subsequent recombination of the resulting polysaccharide radicals during prolonged irradiation. Conclusions: Changes in starch granules could influence some of their functional properties. Rearrangement in the polysaccharide chains could obtain novel starches with defined properties.

Keywords

• HPSEC
• hydrolysis
• molecular weight
• spelt
• starches
• UV radiation