Effects of Thermal and Non-Thermal Pre-Processing Methods on Physical Parameters of Jack bean (Canavalia ensiformis) Seed

Abstract

Effects of thermal and non-thermal pre-processing methods on the physical parameters of jackbean seed were investigated. The bean was subjected to three pre-processing methods roasting and autoclaving which are thermal and sprouting a non-thermal pre-processing method. The physical parameters evaluated include length, width and thickness which were done by the use of digital venier caliper, sphericity index by the use of formula and aspect ratio which is the ratio between length and width. The results of physical characterization revealed that all the pre-processing methods used had effects on the seed. With roasting, there was decrease in all these parameters except sphericity index: length 19.00– 15.00 mm, width 13.00–11.00 mm, thickness 10.75–10.55 mm and sphericity index 72.88–80.20 %. The aspect ratio decreased with pre-processing time for all the treatments used from 1.46- 1.33. Kernel density (g/cm³), bulk density (g/cm³) and density ratio for the untreated seed were 1.24, 0.73 and 0.59 respectively. However, with autoclaving and sprouting, there was increase in length from 19.00–24.00 mm, width 13.00–18.00 mm, thickness 10.75-11.10 mm but a decrease in sphericity index (72.88- 67.46 %) as the pre-processing time increased. These results are very useful in designing of processing equipment for the jackbean seeds thus, encouraging the industrial utilization of the seed.

Keywords: Jackbean, roasting, autoclaving, sprouting