Effect of Conditioning Methods on Mechanical Properties of Raw Bael Fruit

Abstract

Background: Bael is an important indigenous fruit, which is rich in nutritional and health promoting factors. Development of value-added products from this fruit poses a problem as the fruit has a hard rind and is difficult to be removed by hand. Methods: The objective of this investigation was to evaluate the effect of different conditioning methods as normal water dipping (25-27°C), chilling (10-11°C), freezing (4-5°C) and hot water dipping (90-95°C) on firmness and other mechanical properties of raw and matured bael fruit, with a goal of devising some methods for easy removal of the rind. The fruits after conditioning were subjected to puncture test by universal testing machine. Distinct peaks were observed on the force-displacement traces which indicated the rupture force and firmness of the fruits. The changes observed in rupture force, deformation and firmness in conditioned samples were compared. Result: Rupture force measured for control sample (kept under ambient conditions) was 344.4±27.13 N and was found to be lower than that of the conditioned samples. The minimum rupture force of 192.6±14.41 N was observed in frozen sample. No significant difference in rupture force could be observed between the normal water dipped sample and chilled samples. Hot water dipped sample required a rupture force of 215.3±29.2 N, which was not significantly (p greater than 0.05) less than those of other treatments but, the green color of the fruits degraded to brown. The change in other mechanical properties also remained similar. The results would be useful for preparing the raw bael fruit for further processing and value addition.