The search of the potential of modified zeolites as frying fat adsorbents

It is a common practice to add some adsorbent materials into frying oils to extent usa life of it. In this research, the potential of natural zeolite and four modified zeolites as frying oil adsorbent materials to expand use life and productivity of frying oils were determined. Hazelnut oil as frying oil was selected in this study. Natural zeolite was modified with tween 80, cyclodextrine and olive mill water at room temperature and hidrochloric acid at 120 oC, and then modified zeolites were used in 6 consequtive days for dough frying. Some parameters in the control and experimental groups were measured and among all samples the ranges were determined as following; total polar materials (4,09-70,22 %), total polar materials-prob (12,12-84,50 %), free acidity (0,16-1,19 %), smoke point (221,50-184,00 oC), conjugated dienoic acids (0,36-2,19 %), L value (35,65-52,15), a* value (-0,18-5,98), b* value (-3,73-10,40), turbidity (0,70-10,40 NTU), viscosity (67,67-825,50 cP) and fat absorbed by the dough (5,10-8,85 %). The results of this study have shown that both natural zeolite and modified zeolites have different level of activities as frying oil adsorbent materials. While the best results were achieved with tween 80 modified zeolite for the total polar materials, free acidity, instrumental color values, smoke point and conjugated dienoic acid measurements, the best results for turbidity was with oil mill water modified zeolite and best result for viscosity was with hidrocholoric acid modified zeolite. It was determined that adsorbent treatment did not affect fat absorption level of dough fried. In addition, there were significant correlations between the parameters of free acidity, total polar materials, conjugated dienoic acids, viscosity and turbidity values. Smoke point was shown negative correlations with almost all other parameters. Also, the NIR spectroscopic measurements of frying oils have revealed that free acidity with 79 % accuracy (R2 = 0,79), TPM with 90 % accuracy, TPM-prob with 86 % accuracy and conjugated dienoic acids with 87 % accuracy be measured. The wavelength ranges and regression equations of the predictions were also determined. In conclusion, the modified zeolites evaluated in this research were found as active adsorbent materials for frying oils. Especially tween 80 modified zeolite was found as the most appropriate for this purpose. In addition, it is determined that NIR specroscopy is, as in the other analytical uses, a very fast, non-destructive to the sample, and continious analytical technique for frying oil and be used successfully.