CHARACTERIZATION OF ICE RECRYSTALLIZATION IN ICE CREAM DURING STORAGE USING THE FOCUSED BEAM REFLECTANCE MEASUREMENT

摘要

Ice recrystallization was investigated in two commercial and differently formulated ice creams using a rapid and real time granulometric method: the focused beam reflectance measurement. Ice cream A (with locust bean gum as primary stabilizer) and ice cream B (with carrageenan as primary stabilizer) were stored for 154 days at four different temperatures (-5, -8, -12 and -18°C) and three amplitudes of temperature fluctuations (±0.1°C, ±0.75°C, ±2.5°C). Crystal size distribution was assessed at regular time intervals and recrystallization kinetic data was derived by fitting the experimental results to the asymptotic Ostwald ripening model. As expected, recrystallization rates increase with mean storage temperature and amplitude of temperature fluctuations. Carrageenan seems to be more effective than LBG in slowing down ice crystal growth during storage. Mean ice crystal size increased as a function of time 1/3 for both ice creams. The temperature dependence of recrystallization rate fitted Arrhenius well, with activation energies fairly similar for both ice creams.