Chemical analysis of different drying methods

Humidity was determined by pistachio shell drying 5 g of the sample in a room with air flow at a temperature of 2.103 ° C until it reached a constant weight. To determine the properties of pistachio oil, 100 g of pistachio kernels were extracted from each sample as a base in the cold with the help of hexane, which was a solvent.

 

The solvent was evaporated at low temperature. Permitted fatty acids were determined as the percentage of oleic acid using the AOAC titration method. The amount of peroxide was measured using the ionometric titration method recommended by AOAC. Thiobarbituric acid values ​​were determined by adsorption at 532 nm.

 

Percentage of cracks and cracks in pistachio kernels

Five hundred grams of whole pistachio seeds were prepared and the number of seeds with slit shell was counted. Indicators with a thickness of 0.6 mm and a width of 6 mm were used to determine cracked skins. (Iranian Institute of Standards and Industrial Research, 1999)

 

The percentage of cleft skins was calculated from the following equation:

 

100 * Total number of seeds per 500 grams of seeds / Number of seeds with cracked skin in 500 grams of seeds = Percentage of cracked skins

 

Percentage of cracks and cracks in pistachio kernels

 

Evaluation of quality of dried pistachios

A taste test panel was conducted with the participation of 16 trained and experienced people in sensory evaluation of pistachio nuts. Sensory evaluation was performed based on 5-point hydonic scale. They were taught how to use the Hydonic scale and what to consider during the evaluation. The samples were placed at room temperature for 12 hours before evaluation to reach ambient temperature.

 

The panels received 3 nuts in each sample and all sensory assessments were repeated 3 times. The samples are labeled with a three-digit random number and a random order is used to display them. The quality characteristics studied are: firmness, sweetness, sourness, roasted taste, shell form, cracked shells and overall pleasant taste.

 

Evaluation of quality of dried pistachios

 

Analysis of forthcoming test data

The effect of drying methods on different parameters of pistachio seeds was determined using a completely randomized block design (RCBD) after analysis of variance (ANOVA). Significant differences in behavioral methods were compared using the least significant difference (LSD) test at the 5% level using the MSTATC statistical software program version 1.4.

 

Results obtained from the study of different methods of drying pistachios

The results obtained from the study of existing methods in drying pistachios in Iran are reported based on the following 4 parameters:

 

The amount of moisture

Percentage of cracked shell

Fat quality

Structural properties of pistachios

The effect of pistachio drying method on moisture content

There is a significant difference in the moisture content of dried pistachio nuts between the drying methods used in this study (Figure 5). The grain moisture content was less than 4% in all drying methods. Dried grains with vertical and continuous vertical cylindrical dryers have less moisture, which is probably due to their longer shelf life.

 

Dried nuts in all methods had less moisture than standard moisture (6% by weight moisture) suitable for hot and dry areas. Our data are consistent with the data reported by Kamangar and Farsam (1977) who reported that the moisture content of dried pistachio seeds in Kerman province is less than 6%.