engleski

Thermal degradation of anthocyanins in blackberry juice with addition of sugars and starches

Anthocyanins are highly unstable pigments, especially at high temperatures. In this work, investigation of thermal degradation of anthocyanins in blackberry juice with addition of sugars (sucrose, glucose and trehalose) and starches (waxy maize and tapioca) was conducted. Samples were prepared with addition of 10% of sugar and/or 1% of starch and heated at 30, 50, 70 and 90 °C for 60 minutes. Thermal degradation of anthocyanins was investigated through determination of anthocyanin content (AC) and polymeric colour and calculation of the reaction rate constant, half-life of degradation and activation energy. AC ranged from 10.41 mg/L to 29.43 mg/L in a blackberry juice, depending on temperature. When sugars were added AC ranged from 10.14 mg/L to 31.18 mg/L, depending on both temperature and sugar. Samples with addition of glucose and trehalose had higher AC than control sample. Tapioca starch didn’t have significant influence on AC, while samples with addition of waxy maize starch had lower AC than control sample. Samples with combination of sugars and starches had lower AC than control sample. The highest AC had samples with addition of trehalose in combination with both starches. With decrease of AC increase of polymeric colour was observed. Our results could be explained with the interaction between ingredients in blackberry juice.

anthocyanins; heating; blackberry juice; sugar and starch addition

nije evidentirano