Optimisation of development of different dehydrated products from substandard potatoes

Processing of the bulky perishable potatoes into various processed products is viable option which can help to extend the shelflife. Various dehydrated products namely starch, flour, flakes and granules from substandard potatoes collected from 10 different pockets (P) of Kumbapur Farm of University of Horticultural Sciences, Bagalkot, Karnataka were optimized at UAS, Dharwad during 2013–14. Most of the potatoes had brown skin and cream flesh. P₂, P₅, P₆ and P₈ had brownish yellow skin whereas rest showed brown skin. Except for P₃ (yellowish cream skin) most potatoes showed cream and white flesh and all the potatoes were misshaped. Potato tuber mean length breadth and weight varied significantly (p ≤ 0.01). The highest volume (108.70 ml) and diameter (5.62 cm) were found in P₉ potato whereas the lowest values for volume (62.15 ml) and diameter (4.36 cm) was found in P₇ potato tuber. The highest specific gravity was found in P₄ (1.206) and lowest was found in P₆ (1.134) and P₇ (1.134) respectively. Keeping blanching time constant ie 20 minutes the flour/flakes/granules were obtained with variation of temperatures in cabinet drier, drying time and added preservative. The flour/flakes/granules obtained by blanching substandard potato slices for 20 min, drying in cabinet drier at 60°C for 6 h with 5 g preservative were acceptable. The products had attractive colour, texture and taste. Similar results were found for hot air oven method. Starch from substandard potatoes was optimised at drying temperature of 60°C, drying time 2 h, preservative @ 5 g using cabinet drier and hot air oven yielded acceptable product which resembled corn starch in appearance, taste, texture and flavour. Rest of the variations like temperature, drying time with no added preservatives yielded unacceptable starch. Yield of dehydrated products from substandard potatoes revealed that peel loss ranged from 240.45 to 329.6 g/kg. The highest edible portion ranged between 761.41 g/kg to 672.25 g/kg. The yield was highest in flour (171.72 g/kg) followed by granules (95.96 g/kg) and starch yield was the lowest (30.18 g/kg).