Determination of some mechanical properties of Ugu seed (Telfairia occidentalis) in relation to the design of cracking machine

Abstract

Ugu (Telfairia occidentalis) seeds contain valuable oil and other important by-products. Before the oil can be extracted, it has to pass through some processes like depoding, size reduction, cracking etc. The parameters needed in form of engineering properties of the seed to design and construct the processing, storage and handling equipment are not readily available. Therefore, this study was done to determine the following mechanical properties; force at break, energy to break, strain at break and stress at break. Three varieties of seeds (NHTo-1, NHTo-2 and NHTo-3) procured from National Horticultural Research (NIHORT) Institute Ibadan, Nigeria were used. 50 samples from each variety were selected at moisture content 67.734% (wb) and used. Universal Testing Machine (Testometric M500-100AT, 100kN) was used to determine all the mechanical properties. Result showed that the range of mean values at different orientations of diameters were as stated in the brackets: on the major diameter, force at break (28.400±14.064N to 224.857±129.892N); energy at break (0.097±0.044Nm to 0.526±0.481N), strain at break (2.209±0.841% to 11.079±6.672%) and stress at break (0.133±0.069 N/mm² to 1.577± 0.837 N/mm²). On the intermediate diameter, the force at break was (233.667±134.616N to 2043.857±1050,785 N), the energy at break was (0.520±0.054 Nm to 2.604±0.910 Nm), the strain at break was (3.739 ±1.345% to 35.069±10.629%), and stress at break (0.225±0.111 N/mm² to 2.040±0.964 N/mm²). On the minor diameter, the force at break was (53.500± 47.964 N to 363.857±107.606 N); the energy at break was (0.095±0.044 Nm to 1.040 ± 0.548 Nm), the strain at break was (1.909±0.586 to 12.813±3.995 %) and the stress at break was (0.412±0.421 N/mm² to 2.672±0.838 N). NHTo-1 seed variety gave the best crack and did least damage to the kernel on the minor diameter with the mean values of force at break of 53.500±47.964 N.

Keywords: Mechanical properties, Varieties, Ugu seed,  Force at break, Energy to break, Strain at break, Stress at break