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This research was carried out to determine the relationships between pomological characteristics of hazelnuts collected manually from the branch and the ground. The research was carried out in three different orchards belonging to a producer, which contains Tombul, Foşa and Çakıldak hazelnut varieties in Kocaali district of Sakarya province (Türkiye). The orchards, located at an altitude of 300 m, face north. Hazelnut samples of Tombul, Foşa and Çakıldak varieties were collected from the branch in the first (2009) and second year (2010), on 12-15 August, 15-18 August and 22-25 August, respectively, and from the ground on 24-27 August, 27-30 August and 4-7 September, respectively. Nut weight, nut size, shell thickness, kernel weight, kernel size, kernel cavity, kernel percent, shriveled kernel ratio, good kernel ratio, full and average blanching ratios were determined in dried fruits. Correlation analysis was performed between the properties examined separately in the two groups of samples. In the samples collected from the branch and the ground, the highest variation was seen in the shriveled kernel ratio and the lowest in the good kernel ratio. It was determined that all of the significant correlation coefficients in the samples collected from the branch were positive, and the highest correlation coefficients were between full blanching ratio-average blanching ratio, nut weight-kernel weight and nut size-kernel size, respectively. In the samples collected from the ground, more significant correlations, and also negative significant relationships were found between the investigated properties. It was determined that the highest positive correlations were found between nut size-kernel weight, nut weight-kernel weight, full blanching rate-average blanching rate, nut weight-kernel size and nut sizekernel size, respectively; the highest negative correlations were found between the shell thickness-good kernel ratio, the shell thickness-kernel size, and the shriveled kernel ratiogood kernel core ratio, respectively. It can be said that the samples collected manually from the ground in hazelnut were more homogeneous than those collected from the branch in terms of the quality characteristics examined; in the samples collected from the ground, the good kernel ratio and kernel size were negatively affected by the shell thickness, the shriveled kernel ratio was positively affected, and there were no differences between the samples in terms of other relations. [ABSTRACT FROM AUTHOR]

This research was carried out to evaluate the changes of physicochemical contents during storage of 'Tombul' hazelnut cultivar irrigated at the pre-harvest cluster drop period, which is critical for cluster drops, in a conventional rain-fed 'Tombul' hazelnut orchard in Giresun province (Turkey) in 2015 and 2016. The experiment was designed as randomized plots with 3 replications. The plants (multi-stemmed bush) were irrigated with drip irrigation on 16 July (46.08 mm/60 cm), 26 July (44.68 mm/60 cm), 30 July (43.68 mm/60 cm) and 06 August (44.08 mm/60 cm). The dried in-shell hazelnuts were grouped as irrigated and unirrigated (control) samples. 12 kg of in-shell hazelnuts were used in each replication. The hazelnuts were stored in mesh bags under laboratory conditions (20-22 °C and 70-80% relative humidity) for 12 months. The results showed that moisture, ash, oil, and palmitic acid values were significantly affected by the irrigation application. The lowest moisture and ash values, and the highest oil and palmitic acid values were obtained from the samples of irrigated plants. On the other hand, the changes in protein, rancidity, peroxide and vitamin E, and other fatty acids, except for the palmitic acid, were not significant. In conclusion, it can be said that supplementary irrigation in the pre-harvest period has a significant effect on some physicochemical changes during storage in hazelnuts. According to these results, supplementary irrigation can be recommended for hazelnut storage quality in case of insufficient precipitation during the last cluster drop period. [ABSTRACT FROM AUTHOR]

This study was carried out to determine the changes in yield and some quality characteristics of 'Tombul' and 'Palaz' hazelnut cultivars according to orchards varied in terms of photosynthetic active radiation. The study was carried out in three orchards with full day sun lighted (100% PAR), half day sun lighted (66.34% PAR) and shady (49.93% PAR) in the Fatsa district of Ordu province (Turkey) in 2016. The experiment was designed in random blocks and three replicates. As a results, it was determined that lighting conditions of the orchards have a significant effect on yield and quality traits in both cultivars. As the sun lighting decreased, yield and good kernel rates decreased; blank nut ratio increased. In addition, the oil content was decreased as the lighting in the orchards increased but it was found to be significant only in 'Tombul' hazelnut cultivar. As a result, it may be recommended to take into consideration the natural lighting conditions of the orchards in the new plantations, not to plantation the orchard in places that do not have any sunlight and to apply the cultural practices in existing orchards to get enough light. [ABSTRACT FROM AUTHOR]

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In present study, natural hazelnut kernels were treated with, 0.5, 1 and 1.5 kGy of gamma irradiation. The irradiated and untreated hazelnuts were stored at 20 ± 0.5 °C and 55–60% relative humidity for 18 m. After irradiation, 0.5, 1 and 1.5 kGy doses of gamma irradiation significantly increased the total fat values (p < 0.05) and this value decreased during the storage. After treatment, free fatty acid values were similar in untreated and treated hazelnuts. After 6 m of storage, irradiated and untreated hazelnuts had less than 1% free fatty acid values. However, control and 1.5 kGy yielded higher than 1% free fatty acid after 9 m of storage. After irradiation, peroxide values increased proportionally to the dose but the increase was not significant. Peroxide values increased during the storage period (p < 0.05). Control and 0.5 kGy-treated hazelnuts had maximum peroxide values after 9 m of storage, while 1 kGy and 1.5 kGy - treated hazelnuts had maximum levels after 12 m of storage. Applied doses did not cause any significant changes in crude protein, water activity (a w ), crude cellulose and moisture content of hazelnut s (p > 0.05). Storage period significantly affected the water activity and crude cellulose (p < 0.05). Irradiation doses didn’t affect the L*, a* and b* values (p > 0.05), but storage period significantly affected the color values (p < 0.05). At the end of storage period, L* and vitamin E values decreased proportionally to the dose. The 0.5 kGy-treated hazelnuts had the lowest free fatty acid and peroxide values and such a case also reflected in sensory analyses. Furthermore, these hazelnuts had the highest vitamin E value after the control group. Application of 0.5 kGy gamma irradiation seems to be acceptable for natural hazelnut kernels, but food safety issues have to be evaluated in order to recommend its application as a useful conservation alternative. [ABSTRACT FROM AUTHOR]