Antioxidant activity, colour and some nutritional properties of hot air and freeze-dried strawberry tree (Arbutus unedo L.) fruits were investigated. Additionally, the effects of two pre-treatments, namely ethyl oleate and water blanching, were compared in terms of drying characteristics. For determination of antioxidant activities in ethanol extracts, two different analytical methods were used: 1,1-diphenyl-2-picrylhydrazyl scavenging activity and β-carotene bleaching activity. As a result, the ethyl oleate pre-treatment shortened the drying time by hot air method and gave a higher 1,1-diphenyl-2-picrylhydrazyl scavenging activity (82.16 ± 0.34%), total phenolic content (7.62 ± 1.09 µg GAE/g extract), ascorbic acid content (236.93 ± 20.14 mg/100 g), besides hydromethylfurfural was not observed. Freeze-dried fruits exhibited higher ascorbic acid content (368.63 ± 17.16 mg/100 g) than those fresh fruits (231.33 ± 19.51 mg/100 g) and nearly 1,1-diphenyl-2-picrylhydrazyl activity (93.52 ± 0.41 %) to fresh fruits (94.03 ± 1.18%). Colour characteristics, sugar content and mineral contents of fruits were significantly affected by pre-treatments and drying methods (p < 0.05). It is concluded that the drying of strawberry tree fruits should bring a valuable and attractive foodstuff to food industry due to the rich nutritional components, antioxidant activity and colour. Another conclusion from this study is that the freeze-drying is the best drying method to keep the nutritional value, antioxidant activity and sensory properties of fruits.

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The mechanical properties of Nonpareil versus Gulcan 101‐23 almond cultivars that have different shell properties were loaded between two parallel plates to determine the rupture force, rupture energy, rupture power requirement, toughness and firmness. The tests were carried out with three moisture contents, namely, 7.2, 22.9 and 33.6% wet basis and three loading axes (x, y, z). Physical characteristics of the almond cultivars such as length, width, thickness, geometric mean diameter, sphericity, volume, surface area and weight were determined. Physical properties of both cultivars increased as a numerical by increasing moisture content. The highest rupture force in all moisture content levels was obtained for almond pit loaded along the y‐axis. In addition to rupture force, values of absorbed energy, toughness, power requirement and firmness were calculated as mechanical properties. The maximum force required to initiate pit rupture was found as maximum 554.3 N at y‐axis for 7.2% moisture content and minimum 126.9 N at x‐axis for 33.6% moisture content for Gulcan 101‐23 cultivar. These values were determined as 53.3 and 11.2 N, respectively, for Nonpareil cultivar. Rupture force, absorbed energy, toughness, power requirement and firmness decreased with an increase of moisture content. The difference between mechanical properties of Nonpareil versus Gulcan 101‐23 almond cultivars was found to be highly significant (P < 0.001). PRACTICAL APPLICATIONS As almond production increases in the world, almond processes are performed by hand or by using old techniques. Therefore, major quality loss during harvesting and postharvesting processes of almonds occurs. The most critical and delicate operation in postharvesting processes is pit cracking to extract the fragile whole edible kernel from the almond pit. This process is still carried out by hand or by using an apricot cracking equipment. But this is not the right process because shell hardness of almond pit changes in relation to almond cultivars. While some almond pits can be cracked using high power and some apparatus, some of them can be cracked even by hand easily. The cracking operation causes damage and broken kernels because of the excessive mechanical forces. The extent and type of damage depend on the physical characteristics, cultivar and applied force. For this reason, systems must be designed while taking these criteria into consideration to prevent inadequate applications.

The drying characteristics and changing of water activity (Aw) values of Kirmizi and Siirt pistachio cultivars were determined experimentally as a function of drying air temperature and initial moisture content during hot air drying. The drying experiments were conducted using two levels of initial moisture content (32 and 38%) and three drying air temperatures (40, 50 and 60C) at 1.5 m/s drying air velocity at 12% air relative humidity. The drying curves obtained from the experimental data were then fitted to the 10 different semitheoretical and/or empirical thin‐layer drying models. The moisture ratios at any drying time were compared by the Newton, Page, Henderson and Pabis, Logarithmic, Two‐term, Wang and Singh, Diffusion approximation, Modified Henderson and Pabis, Verma et al. and Midilli et al. models. The effect of drying air temperature and initial moisture content on the coefficients of the best‐suited moisture ratio model were determined by multiple regression method. Root mean square error and reduced chi‐square were used for the determination of the best suitable model. In addition to these statistical parameters, the modeling efficiency was also determined. The Modified Henderson and Pabis model was found to be the most suitable for describing the drying behavior of both pistachio cultivars. As a criterion of shelf life, Aw changes of dried pistachio samples were investigated. PRACTICAL APPLICATIONS Proper harvesting and postharvest handling are basic parts to achieve maximum yield of good quality nuts that determine marketability and profit. Processing right after harvesting is very important to pistachio quality. Drying is an important operation in pistachio processing. During the drying process, nuts can undergo reactions that cause loss of nutritional value and enzymatic activity. It is therefore necessary to design and simulate accurately the drying systems for pistachio nuts. For this reason, knowledge of such nut properties as thin‐layer drying characteristics under different drying conditions is required. Also changing of water activity values is also important for different drying and storage conditions in practical applications because the most effective preventative control is to dry pistachio nuts to a water activity of 0.82 for short‐term or 0.70 for long‐term storage to prevent mold growth and aflatoxin contamination.