Macro-structural characterisation of palm fruit at different processing conditions

Characterisation of palm fruit was undertaken by determining some macro-structural (physical and mechanical) properties of palm fruit (tenera variety) at different processing conditions, such as sterilisation time and duration of digestion. The true density of fruit sterilised for 0 to 90 min from 996 to 987 kg/m(3) while the bulk density decreased from 611 to 577 kg/m(3). The density ratio decreased from 61.5 to 58.5 while the porosity increased from 38.6 to 41.5%. For the sterilised and digested fruit, the true density increased from 806 to 913 kg/m(3) with increase in sterilisation time from 30 to 90 min and duration of digestion from 5 to 15 min. The bulk density also increased from 538 to 688 kg/m(3) within the same range of sterilisation and digestion. The fracture resistance and fruit bruising pressure of the palm fruit decreased from 1446 to 318 N and 2.34 N/mm(2) to 0.79 N/mm(2), respectively, when the fruit was sterilised for 0 to 90 min. These results will inform the modelling of the fruit sterilisation and digestion operations for optimisation of the overall palm oil extraction process. (c) 2006 Published by Elsevier Ltd.