Determination of effects of irrigation on flavor and quality of pistachio nuts

Effect of irrigation on flavor of Uzun and Siirt variety (Early harvest and mature) of fresh and dried pistachio nut was determined with Head Space-Solid Phase Microextraction/Gas Chromatography-Mass Spectroscopy, Gas chromatography-Olfactometry techniques and sensory analyses. The effects of irrigation on some quality parameters (fat content, total protein, total sugar, moisture content, acidity and texture) of pistachio were also investigated. According to the results of analyses, the moisture content of fresh pistachio increased by irrigation whereas oil content, protein content, sugar content, pH and hardness of pistachio did not affected by irrigation. Totally 39 volatile compounds in dried pistachio nut and 33 volatile compounds in fresh pistachio nuts were determined. The volatile compounds of pistachio nut were mostly composed of terpens. Alpha pinene, beta mycrene, limonene, alpha terpinolene, 1 pyrole- 1 methyl, Z- beta ocimene, butrylactone, p-cymene and p-cymenene were the major volatile compounds in dried pistachio nut. On the other hand, alpha pinene, beta pinene, beta mycrene, limonene, alpha terpinolene, isoamyl alcohol and acetoin were the major volatile compounds of fresh pistachio nut. In the olfactometric analyses, 35 odor active compounds and 32 odor compounds were determined in dried and fresh pistachio, respectively. It was found that irrigation affected the flavor of pistachio. Cultivation of pistachio in irrigated conditions had lowered the concentration of volatile compounds and odor intensities of active compounds than that of non-irrigated condition.