Technological modes of pressing for cherry kernel oil production

Introduction.The aim of the research was to study the influence of temperature and duration of wet-heat treatment and pressing on the process of oil extraction from cherry pits.Materials and methods.The raw material for making oil was the kernels of the following cherry cultivars: English Early, Lotivka, Lyubska, Griotte d'Ostheim, Podbyelska, and their mixture (20% of each sample).Treating cherry pits with NaCl solution was used.Modes of wet-heat treatment and pressing were studied.Results and discussion.It was proposed to treat pits with NaCl.The mode selected as the most suitable for pits of different cherry varieties involves treating them with NaCl solution (one part rock salt to one part water) for 5-10 min.This treatment ensures that 90-100% of the pits crack.Thus, this is the optimum solution ratio to make this operation effective, which gives reasons for the proposed improvement of the technology.Process conditions of cold pressing (extra virgin) have been determined for kernels of various cherry cultivars.The most practical temperatures of wet-heat treatment of crushed cherry kernels were as follows: 50-60C and duration of 5-10 min for Podbyelska, English Early, Lotivka, Lyubska, and the mixture; 40-50C and duration of 10-15 min for Griotte d'Ostheim.It has been found that the pressing of cherry kernels was effective at temperature 60-70C and duration of 6-15 min for Podbyelska, English Early, Lotivka, Lyubska, and the mixture, and at temperature 50-60C and duration of 4-10 min for Griotte d'Ostheim.The parameters of the pressing extraction stage most effective for the kernels of all the cherry cultivars were: residual oil content in the oilcake 5.0-6.0%;oil yield 94.0%; oilcake thickness 1.8 mm (English Early), 2.0 mm (Lotivka), 1.7 mm (Lyubska), 2.2 mm (Griotte d'Ostheim), 2.0 mm (Podbyelska), and 1.8 mm (the mixture); load resistance time 6 min (English Early), 8 min (Lotivka), 10 min (Lyubska), 4 min (Griotte d'Ostheim), 10 min (Podbyelska), and 15 min (the mixture); and, for all samples, compressive strength 10.0 kN and rate of load application 5.0 kN/cm. Conclusion.The results showed the practical value of preliminary processing of cherry pits before removing kernels from them, substantiated the choice of temperature and duration of their wet-heat treatment and pressing.The results were confirmed when these methods were introduced into the technology of oil production from cherry kernels of different varieties.