Bài báo khoa học

Black shallots are new products from shallots (Allium ascalonicum), which are processed by controlled aging at an appropriate temperature and humidity. In this study, the freezing pretreatment and the ultrasonic pretreatment were applied experimentally in the black shallots production process to break cell structure while maintaining external appearance of the raw materials. The study evaluated the effect of freezing pretreatment (-20oC, 30 h) (1); ultrasonic pretreatment (28 kHz, 2 h) (2) together with the control sample (no pretreatment) to the cell structure of the shallots; at the same time, the browning degree, reducing sugar content, total amino acids, bioactive compounds (total polyphenols, total flavonoids), antioxidant activity and sensory quality during a 27 day heatprocessing (70°C, 80% RH) were investigated. The results showed that under the conditions in which the pretreatment was performed, the frozen pretreated shallots had the highest content of biological compounds and antioxidant activity in the shortest heat-processing time. Therefore, freezing pretreatment can be considered as promising methods to shorten the production time and develop black shallot products with good sensory and functional properties.