The Quality Assessment of Sour Cherries Dried Using an Innovative Simultaneous Osmotic–Microwave–Vacuum Approach Based on Image Textures, Color Parameters, and Sensory Attributes

Abstract

Sour cherries are a perishable raw material, and their preservation is needed to extend their availability to consumers. Improving drying techniques is desirable to ensure the highest quality of products. This study aimed to determine image textures from color channels R, G, B, L, a, b, X, Y, and Z; color parameters L*, a*, and b*; the color difference (ΔE) of raw materials and dried fruit; and the sensory attributes of dried sour cherry products prepared using an innovative approach. Three sour cherry cultivars, ‘Nefris’, ‘Debreceni Botermo’, and ‘Łutówka’, were used in the experiment. Sour cherries were subjected to freezing and pit removal before drying. The simultaneous osmotic–microwave–vacuum drying was carried out in one process lasting an hour and combining osmotic dehydration using a 40 °Bx sucrose solution and microwave–vacuum drying at microwave powers of 100 W for 900 s, 300 W for 900 s, 250 W for 900 s, and 0 W for stabilization for 900 s and a pressure of 30 ± 2 hPa. After drying, the quality assessment of products was performed using non-destructive image analysis and color measurements, as well as sensory analysis, including non-destructively and destructively assessed attributes. The highest changes in textures occurred for the GHMean (histogram’s mean for color channel G) (from 30.69 to 22.64) and LHMean (histogram’s mean for color channel L) (from 66.93 to 59.07) of images of the cultivar ‘Łutówka’, and the smallest changes were found for the cultivar ‘Nefris’. Drying had a statistically significant effect on the color parameters of the ‘Debreceni Botermo’ and ‘Łutówka’ sour cherries. The value of ΔE was the highest (10.44) for ‘Debreceni Botermo’ and the smallest (1.98) for ‘Nefris’. All cultivars of dried sour cherries had very high values of overall quality, reaching 8.9 for ‘Nefris’ and ‘Debreceni Botermo’ and 8.8 for ‘Łutówka’. The ‘Nefris’ sour cherry was characterized by the highest value of flavor of 9.0. All dried samples were attractive in terms of their external appearance. The sensory parameters related to taste, texture, and crunchiness were also satisfactory. Innovative simultaneous osmotic–microwave–vacuum drying allowed for the obtainment of dried sour cherries with a high quality, including acceptable sensory attributes.