شارك الاستاذ الدكتور محمد حجتي في كلية الزراعة قسم علوم و تكنولوجيا
الاغذية في جامعة العلوم والموارد الطبيعية في خوزستان ، الأهواز ، إيران بحثا
بعنوان (Effect of UV-treatment on drying properties
of Ziziphus mauritiana)
و تضمن البحث
Abstract
In the present study, the effect of UV-B
pretreatment in three times of 30, 60 and 90 minutes on the antioxidant
activity, vitamin C, total phenolic compounds, rehydration, shrinkage and to
model the drying kinetics of hot air dried Ziziphus mauritiana fruit at three
temperatures of 40, 50 and 60°C using several mathematical models such as the
Henderson–Pabis, logarithmic, two-term, Verma, Wang and Singh, Midilli, and
modified Henderson–Pabis models were investigated. The results showed that the
use of UV-B pretreatment before fruit drying significantly reduced the drying
time and had a significant effect on the physicochemical properties of the
fruit. This pretreatment reduced the
shrinkage and increased rehydration and the effective moisture diffusion coefficient.
In addition, using the UV-B pretreatment decreased the loss of the total phenol
compounds, antioxidant activity, and the amount of vitamin C. The amount of
activation energy increased from 34.84 (control sample) to 36.72 kJ / mol (UV-B
pretreatment samples for 30 minutes), 38.67 (UV-B pretreatment samples for 60
minutes) and 41.37 (UV-B pretreatment samples for 90 minutes) (KJ / mol). On
the other hand, increasing the hot-air drying temperature increased the
shrinkage and decreased the rehydration, vitamin C and the amount of the
phenolic compounds. Finally, the modified Henderson–Pabis model with the
highest correlation coefficient (R2) and lowest root mean square error (RMSE)
and chi-square (?2) showed the best fit for every drying curve, proving to be
an excellent tool for the prediction of drying time. In conclusion, the use of
UV-B could be recommended as a suitable pretreatment in drying fruit.
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