Interactions between tea products and wheat starch during retrogradation

Interactions between tea products (tea polyphenols and catechins) and wheat starch (WS) during retrogradation were investigated. Tea product-fortified WS showed retarded retrogradation based on thermogravimetric analysis, X-ray diffraction, and Fourier-transform infrared spectroscopy (FT-IR). Thermogravimetric analysis showed that the addition of tea products led to the shift of the degradation temperature of WS toward lower temperature, indicating changes in the starch structure due to interaction with tea products. Tea product-WS mixtures had less crystallinity than controls during storage at 4°C, which was more noticeable for samples treated with tea polyphenols. In FT-IR spectra, tea product-WS complexes gave broadened O–H stretching and C–O–H bending vibrations compared with controls. Tea products presumably formed hydrogen bonds with WS, interfering with the reassociation of starch chains during storage, and thereby delaying retrogradation. Thus, tea products may be used as potential anti-retrogradation additives in the food industry.