Abstract:

In order to investigate the effect of gelatin dosage on the adsorption of tannic acid, 0.01–0.11 g of gelatin
was used to adsorb 25 mL of 900 mg/L tannic acid model solution. The gelatin dosage was optimized for the adsorption
capacity of gelatin and the removal rate of tannic acid. The adsorption kinetics and adsorption isotherms of tannic acid by
gelatin were explored as well. In addition, the effect of gelatin adsorption on blueberry juice astringency was examined.
The results showed the optimal gelatin dosage was 0.03 g, leading to an adsorption capacity of 527.5 mg/g and a removal
rate of tannic acid of 70.33%. The adsorption of tannic acid by gelatin was described by pseudo-second order adsorption
kinetics; the adsorption isotherm was described by Langmuir adsorption model and it was monolayer adsorption. When 25
mL of blueberry juice containing 900 mg/L tannic acid was shaken at 15 ℃ for 20 min after addition of 3 g of gelatin, the
adsorption capacity was 420.8 mg/g and the removal rate of tannic acid was 56.11%.

Key words: blueberry juice, gelatin, tannic acid, adsorption