Optimization of Hydropriming of Okra (Abelmoschus esculentus) Seeds Using Response Surface Methodology

Abstract

This research study was envisaged to evaluate the effect of parameters, viz. initial germination percentage (IGP), soaking duration (SD), temperature, rotation speed (rpm) and air flow rate (AFR) for hydropriming of Okra (Abelmoschus esculentus L.) seeds. Three different seed lots based on their moisture content and germination percentage were chosen in this study. Moisture content and germination percentage of the selected lots varied from 11.33 to 16.89% (d.b.) and 50 to 80%, respectively. Accelerated ageing was performed at 40 ± 1°C, 100% relative humidity to obtain required lots from available seed sample. Response surface methodology was adopted using a five factor three-level Box-Behnken design with soaking duration (4, 5 and 6 h), temperature (20, 25, 30°C), rotation speed, (320, 340, 360 rpm), air flow rate, (2.192, 2.740, 3.288 m 3 /min) as the main process parameters. The effect of process affecting parameters was observed on responses, viz. moisture content, germination percentage, seedling length, seedling dry weight, vigour index-I, vigour index-II, electrical conductivity and radiography. Models were found to be significant for all the process responses with the optimal solution as 73% (IGP), 6 h (SD), 23°C temperature, 330 (rpm) and 2.50 m 3 /min (AFR).