The aim of this study was to obtain extracts of anthocyanin pigments from red and purple-fleshed potato juices characterized by stable color. For this purpose, potato juices were pasteurized at different temperatures or fruit and vegetable concentrates were added to them. Color stability tests of the obtained pigments were carried out in model pH and temperature conditions and after adding to natural yogurt. Both the pasteurization process and the addition of fruit and vegetable concentrates to the potato juices positively affected their color and its stability in time. However, the pasteurization of the potato juices had a negative effect on the content of biologically active compounds, in contrast to the juices stabilized with the addition of fruit and vegetable concentrates. Anthocyanin pigments from red-fleshed potato juices were more stable than those isolated from the purple-fleshed potato juices. The results of model tests of the anthocyanin pigment concentrates from the colored-flesh potatoes and natural yoghurts with their addition confirmed the high stability of the tested concentrates.

Sensory evaluation is essential for analyzing fish quality, as it describes its organoleptic profile and reflects consumer perception. Attributes such as appearance, smell, taste, and texture can vary depending on the origin of the fish, its diet, and thermal processing. In order to obtain reproducible results, it is necessary to control factors such as temperature, cooking time, and portion thickness during fish sample preparation for testing. This study develops a standardized guide for the sensory evaluation of cooked fish, particularly Sparus aurata. The guide includes detailed preparation protocols, a structured descriptive method, and a tasting sheet to ensure objective, reproducible evaluations that are applicable in research, industry, training, and quality control.