Influence of drying methods on preservation of colour and quality attributes in celery (Apium graveolens L.) and dill (Anethum graveolens L.) leaves

Lack of appropriate drying methods for celery and dill green leaves results in significant losses in sensory attributes, color, and physical quality. In addition, improper drying accelerates antioxidant degradation due to rapid moisture loss and chlorophyll breakdown. To overcome this constraint, effect of four drying methods viz ., low-temperature cabinet drying (LTCD), shade drying (ShD), hot air oven drying (OD), and sun drying (SuD)were assessed on the physical and biochemical quality attributes of celery ( Apium graveolens L.) and dill ( Anethum graveolens L.) leaves. Key parameters assessed included sensory characteristics, colour, browning index, color retention index and maillard index, rehydration capacity, chlorophyll, carotenoides, antioxidant activity, essential oil composition and odour activity value (OAVs). Among the studied methods, leaves dried under low-temperature cabinet drying with dehumidifier at 20 °C and with a relative humidity of 25-30%resultedin thehighest overall acceptability (7.28 and 7.66) in sensory evaluation and demonstrated superior color retention with minimal chlorophyll degradation (3.36 & 5.36) and total carotenoids (0.67, 0.32) in both crops i.e ., celery and dill, respectively. It also preserved antioxidant activity, including DPPH scavenging, total phenolics, and ascorbic acid, while maintaining the highest rehydrationratio (5.72, 5.5) and coefficient of rehydration (0.71, 0.70). OD yielded the lowest water activity (aw) values 0.200 (celery) and 0.190 (dill) followed by LTCD and SuD, while ShD produced the highest aw values: 0.249 for celery and 0.240 for dill . Although all drying methods reduced EO volatiles compared to fresh leaves, LTCD retained the highest content of major constituents. Principal Component Analysis indicated that LTCD and OD offered balanced preservation of quality attributes, whereas SuD and ShD resulted in significant quality deterioration. From the result of this investigation, LTCD is recommended as the most effective method for preserving the high quality of dried celery and dill leaves, with the potential for optimization in commercial applications.