of 0.12 l/min) for 0 to 10 min. While L-and b-values showed significant increases, the a-value of apple juice samples decreased as treatment time and concentration of ozone increased. In the case of ozone treated freshly squeezed orange juice (Tiwari et al., 2008) and blackberry juice
(Tiwari et al., 2009a), an increase inL-value and decreases ina-andbvalues resulted. However, in our study, no significant changes of L-,a-, and b-values were found in apple juice treated with ozone and heat. The differences in color changes of fruit juices among the various studies may be caused by different systems consisting of various control parameters such as concentration, gasflow of ozone, and treatment time. Especially, treatment time in the current study was shorter than that of the cited studies