Dried pistachios at 75 ° C taste better
Research shows that about 50% of consumers prefer the taste of dried pistachios at 75 ° C.
Hamid Reza Gazer, PhD student in Agricultural Machinery Mechanics, Science and Research Unit, in a part of his dissertation entitled Study and evaluation of effective components in the design of Iranian pistachio dryers, the effect of temperature parameters and air movement speed on drying time and index of drying time Is.
The findings of this study indicate that more than 27% of people tend to consume dried pistachios at a temperature of 90 ° C. Only between 37.20 and 68.23% of consumers are inclined to taste dried pistachios at a temperature of 60 ° C.
This means that roasted baits are more popular with consumers. According to the results of this study, increasing the temperature and hot air transfer rate are effective factors in the drying process of pistachios and can increase the drying time from 60 to 90 ° C to reduce the process time to about 37%.
The amount of this decrease for increasing the temperature from 60 to 75 degrees Celsius reaches 24%. Also, by increasing the air speed from 1.5 to 2.5 meters per second, about 10% of the drying time of pistachios is reduced.
The findings of this study, which was compiled under the guidance of Dr. Saeed Minaei, a member of the faculty of the Institute of Technical Research and Agricultural Engineering, indicate that one of the most important stages of pistachio processing is the drying stage.
At this stage, the moisture content of the product is reduced from about 50% to less than 5% based on dry weight so that the product can be stored properly; Therefore, the study of the effects of effective parameters in this process can play an important role in determining the drying time and maintaining product quality.
In this dissertation, the effect of temperature changes in three levels of 60, 75 and 90 ° C and hot air velocity in three levels of 1.5, 0.2 and 5.2 m / s on drying time and quality indicators of pistachio crop Changes in the amount of protein, fat and peroxide number in two cultivars of Iranian pistachios (Kolechoochi and Hazelnut) were studied; Also, through taste test, the effect of temperature on the taste of dried pistachios in the three mentioned levels was investigated.
The statistical results obtained for both pistachio cultivars showed that changes in temperature and air movement speed have a negative effect on the drying time of pistachios and increasing the temperature from 60 to 90 ° C can reduce the drying time by about 37%; Also, in terms of quality, changes in temperature and air velocity have no negative effect on the amount of protein and fat in pistachio products.
With increasing temperature, the amount of peroxide number increases significantly, but this increase, which is a maximum of 0.555 mEq / kg for 90 ° C, is less than the allowable limit for pistachios.