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Convective drying and quality attributes of elephant foot yam (Amorphophallus paeoniifolius)

Author:
Srikanth, K.S., Sharanagat, Vijay Singh, Kumar, Yogesh, Bhadra, Ria, Singh, Lochan, Nema, Prabhat K., Kumar, Vijay
Source:
Lebensmittel-Wissenschaft + [i.e. und] Technologie 2019 v.99 pp. 8-16
ISSN:
0023-6438
Subject:
Amorphophallus paeoniifolius, activation energy, air drying, ambient temperature, blanching, calcium oxalate, citric acid, color, curry, diffusivity, drying temperature, energy, hardness, models, potassium metabisulfite, rehydration, sweets, texture, yams
Abstract:
The study evaluated the effects of convective hot air drying temperatures (40, 50, 60 and 70 °C) with different pre-treatments (Potassium metabisulphite (KMS) and KMS + Citric acid) on drying as well as rehydration kinetics, color, texture and calcium oxalate content of elephant foot yam (EFY) cubes. Moisture diffusivity (6.69 × 10−8-3.41 × 10−7 m2/s) and activation energy (25.18–32.46 kJ/mol) increased with pre-treatments and increase in drying temperature. Rehydration ratio increased with increase in drying as well as rehydration temperature compared to room temperature. Page and modified peleg models suited the best to describe drying and rehydration kinetics of EFY cubes, respectively. Color value ‘L’ decreased with increase in drying temperature and opposite trend was observed for ‘a’ and ‘b’ value. However the dried samples treated with KMS + blanching showed higher ‘L’ value and the highest L value (90.35) was observed at 50 °C. Sample hardness (94.34–349.57 N) and rupture energy (18.42–191.35 N/mm2) decreased with increase in drying temperature. Significant (p < 0.05) reduction in calcium oxalate (120–13.5 mg/100g) was observed during drying. Sample dried at higher temperatures had lower oxalate content and hardness which can be potentially used in curry making, bakery and confectionary products.