Drying kinetics, quality and moisture diffusivity of spouted bed dried Sri Lankan black pepper

• Published in: Journal of food engineering 2019-12, Vol.263, p.38-45
• Main Authors: Jayatunga, G.K., Amarasinghe, B.M.W.P.K.
• Format: Article
• Language: English
• Subjects: Black pepper; Black pepper essential oil; Drying kinetics; Moisture diffusivity; Spouted bed dryer
• ISSN: 0260-8774; 1873-5770
• DOI: 10.1016/j.jfoodeng.2019.05.023

Drying of black pepper has been investigated in a lab-scale conventional spouted bed dryer. Spouting behavior of black pepper was studied, and the minimum spouting velocity was determined. The effect of operational conditions; drying temperature, air velocity and stagnant bed height on drying kinetics was analysed. The higher values of drying rates were achieved when the dryer was operated with moderately high temperatures, high airflow rates and shallow beds. The results show an increase in effective moisture diffusivity with increasing drying temperature. The highest effective moisture diffusivity of 2.03 × 10-10 m2/s was obtained at a hot air temperature of 75 °C. Extraction and analysis of essential oil from dried black pepper showed that the variation of oil yield with drying temperature is significant for drying temperatures from 45 °C to 75 °C 65 °C was selected as the best drying temperature for black pepper drying in the conventional spouted bed dryer. •Raw black pepper was dried in a spouted bed dryer.•The minimum spouting velocity of raw black pepper in the spouted bed was determined for different bed heights.•Higher values of drying rates were achieved when the dryer was operated with moderately high temperatures, high airflow rates and shallow beds.•65 °C was found as the best drying temperature for black pepper drying in the spouted bed dryer in order to obtain highest yield of black pepper essential oil.