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AbstractInfluence of microwave power on dehydration kinetics as well as quantity, chemical composition and antioxidant potential of peppermint essential oil was evaluated. The leaves were dried using microwave powers of 200, 400 and 800 W, and the essential oils extracted by hydro-distillation. The antioxidant potential of the essential oils was quantified by DPPH radical-scavenging activity method. The obtained results showed that increasing microwave power caused significant decrement (p≤ 0.01) in drying duration. Drying over the considered microwave powers reduced essential oil yield significantly (p≤ 0.01). In total, 36 compounds were identified in the essential oils belonging mainly to oxygenated monoterpenes. The main constituents namely menthol, menthone and menthyl acetate showed significant variation (p≤ 0.01 or p≤ 0.05) with the drying process. Antioxidant assaying indicated significant effect (p≤ 0.05) on radical scavenging activity of the essential oil by drying and essential oil concentration. Compared to the fresh samples (with an IC50of 103 μg/ml), the leaves dried at microwave power levels of 200, 400 and 800 W resulted in significant lower antioxidant activities with IC50values of 201, 291 and 615 μg/ml, respectively.

Saffron is the most precious and expensive agricultural product. A dehydration treatment is necessary to convert Crocus sativusL. stigmas into saffron spice. To the best of our knowledge, no information on mass transfer parameters of saffron stigmas is available in the literature. This study aimed at investigating the moisture transfer parameters and quality attributes of saffron stigmas under infrared treatment at different temperatures (60, 70, …, 110°C). It was observed that the dehydration process of the samples occurred in a short accelerating rate period at the start followed by a falling rate period. The effective moisture diffusivity and convective mass transfer coefficient were determined by using the Dincer and Dost model. The diffusivity values varied from 1.1103×10−10m2·s−1to 4.1397×10−10m2·s−1and mass transfer coefficient varied in the range of 2.6433×10−7–8.7203×10−7m·s−1. The activation energy was obtained to be 27.86kJ·mol−1. The quality assessment results showed that the total crocin content increased, when the temperature increased up to 90°C but, in higher temperatures, the amount of crocin decreased slightly. The total safranal content of the samples decreased slightly when drying temperature increased from 60°C to 70°C and then continuously increased up to 110°C. Also, the amount of picrocrocin increased from 83.1 to 93.3 as the drying temperature increased from 60°C to 100°C.

The aim of this study was to analyse input–output energy and economical assessment of almond production in three age groups of orchards (group I 6–10, group II 11–15 and group III 16–20 years old) in Chahrmahal-Va-Bakhtiari province, Iran. Data for almond production were collected by administering questionnaire in face-to-face interviews from the orchards selected based on random sampling method during a 3-year period. The results showed that 57,027.13, 60,341.14 and 61,640.43 MJ ha−1energy was consumed by group I, group II and group III, respectively. The most energy input was consumed by electricity, followed by chemical fertilizer. Energy indices were calculated, and the results revealed that energy efficiency was 0.62, 1.12 and 0.81 in the triple groups of orchards, respectively. Economical assessment showed that total production cost of almond in group I, II and III was $4547.54, $5799.26 and $5687.05 ha−1, respectively. In all orchard groups, the shares of variable and fixed production costs found to be same nearly. Net return for almond production was $14,516.22, $30,735.19 and $21,395.57ha−1, respectively. According to the research results, it was concluded that although almond production in the study region was not an efficient process in terms of energy consumption, it was a profitable agricultural operation.