Effect of Slice Thickness and Blanching Pretreatment on the Physicochemical, Nutritional, Colour, and Microbial Quality of Elephant Foot Yam [Amorphophallus paeoniifolius (Dennst.) Nicolson] Powder during Storage
S V Vasantha
*
Division of Post Harvest Management, ICAR-IARI, New Delhi - 110012, India.
Nilam V. Patel
Department of Post Harvest Technology, ASPEE College of Horticulture, Navsari Agricultural University, Navsari- 396450, India.
H S Roja
Division of Fruit Science, IARI-IIHR, Hesaraghatta, Bengaluru, Karnataka-560089, India.
S V Suvarna
Department of Plantation, spices, medicinal and aromatic crops, College of Horticulture, University of Horticultural Sciences, Bagalkot, Karnataka-587104, India.
Shridhar Ramesh Emmi
Division of Vegetable Science, IARI-IIHR, Hesaraghatta, Bengaluru, Karnataka-560089, India.
G R Nithya
Department of Fruit Science, College of Horticulture, University of Horticultural Sciences, Bagalkot, Karnataka-587104, India.
*Author to whom correspondence should be addressed.
Abstract
Elephant foot yam [Amorphophallus paeoniifolius (Dennst.) Nicolson] is a nutrient-rich tuber with high post-harvest perishability. This study evaluated the combined effect of slice thickness (2, 4, and 6 mm) and blanching pre-treatments (water blanching for 3 and 5 min, microwave blanching for 30, 60, and 90 s, and unblanched control) on the physicochemical, nutritional, colour, and microbial quality of cabinet-dried elephant foot yam powder during six months of ambient storage (25±2°C, 60–70% RH). A factorial completely randomised design with three replications was used. Final powder moisture content was 6.5–7.8% (wet basis) with water activity < 0.60. Slice thickness and blanching significantly affected most quality parameters (p < 0.05). Unblanched samples retained higher nutritional constituents (e.g., starch up to 62.82%, ash up to 4.94%), while water blanching caused greater leaching losses. Microwave blanching offered better overall quality retention. During storage, total sugars and reducing sugars increased (7.44% to 7.59% and 2.13% to 2.48%, respectively), while starch, protein, ash, and crude fibre declined. Colour darkened (L* decreased from 19.22 to 14.48). No microbial growth (less than 10 CFU/g detection limit) was detected in any treatment throughout storage. The combination of 2 mm slice thickness with 30 s microwave blanching was most effective overall, providing optimal balance of nutritional retention, colour stability, processing efficiency, and shelf stability. These findings support value addition and industrial utilisation of elephant foot yam.
Keywords: Elephant foot yam powder, Amorphophallus paeoniifolius, slice thickness, blanching, physicochemical properties, nutritional quality, colour parameters, storage stability, total plate count