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Effects of hot air and combined microwave and hot air drying on the quality attributes of celery stalk slices

Celery (Apium graveolens) has extensive culinary usage given its characteristic aroma and flavor, which are due to the presence of butylphthalide and sedanolide. The aim of this work was to study the preparation of dried celery stalk slices through hot air or combined microwave and hot air drying at 50, 60, or 70°C with or without blanching pretreatment. The celery stalk slices that were dried at low temperatures retained aroma well. Although blanching reduced drying time (DT) and global color change, it also reduced the retention of the characteristic aroma of celery. Therefore, combined microwave and hot air drying without blanching was selected for celery stalk slices given that it reduced DT, minimized chromatic aberrations, and maximized the retention of the characteristic aroma of celery. PRACTICAL APPLICATIONS: Celery has extensive culinary usage given its characteristic aroma and flavor, owing to the presence of butylphthalide and sedanolide. Dried celery slices can be used as food flavorings in conventionally cooked and ready‐to‐eat products. Hot air and microwave drying with blanching pretreatment was investigated to dry celery to preserve its nutritional value, flavor and reduce postharvest losses. The obtained the process parameters are helpful for the application of combined microwave with hot air drying technology to preserve good quality, especially flavor of dried celery.