Abstract

 The physical properties of red pepper seed were evaluated as a function of moisture content. The average length, width and thickness were 4.46, 3.66 and 0.79 mm, respectively, at 7.27% d.b. moisture content. In the moisture range of 7.27 to 20.69% dry basis (d.b.), studies on rewetted red pepper seed showed that the thousand seed mass increased from 7.97 to 8.89 g, the projected area from 8.40 to 9.09 mm², the sphericity from 0.525 to 0.555 and the terminal velocity from 4.36 to 4.51 m s^-1. The static coefficient of friction of red pepper seed increased linearly against surfaces of four structural materials, namely, rubber (0.394 to 0.477), aluminium (0.255 to 0.382), stainless steel (0.298 to 0.416) and galvanised iron (0.319 to 0.395) as the moisture content increased from 7.27 to 20.69% d.b. The bulk density decreased from 402.1 to 360.0 kg m^-3, the true density from 795.2 to 746.3 kg m^-3 and the porosity increased from 49.43 to 51.76%, respectively, with an increase in moisture content from 7.27 to 20.69% d.b.

Key words: Red pepper seed, physical properties, moisture content, terminal velocity. 

Abbreviation

A_p, Projected area, mm²; L, length of seed, mm; m₁₀₀₀, thousand seed mass, g; M_c, moisture content, % d.b.; M_f, final moisture content of sample, % d.b.;M_i, initial moisture content of sample, % d.b.; P_f, porosity, %; Q, mass of water to added, kg; T, thickness of seed, mm; V_t,  terminal velocity, m s^-1;  W, width of seed, mm; W_i, initial mass of sample, kg; a,angle of tilt, degree; m, static coefficient of friction; r_b, bulk density, kg m^-3; r_t, true density, kg m^-3; f, sphericity of seed; al, aluminium; gi, galvanised iron; ru, rubber; ss, stainless steel.