Physical properties and magnetic resonance imaging of the Australian green plum (Buchanania obovata) through maturity and ripening and across locations

The green plum (Buchanania obovata) is a small fruit eaten by Aboriginal people in the northern parts of Australia. The trees grow in remote locations and the fruit has received very little study by Western food science. This study aims to profile and analyse physical characteristics of the green plums as they grow and ripen across multiple locations and harvests. Fruit from four locations, five maturity stages and two harvests were characterised using standard physical measurements, magnetic resonance imaging (MRI), moisture content, titratable acidity, pH, total soluble solids, and ethylene, oxygen and carbon dioxide gas analysis. Results of the physical measurements were analysed with multivariate data analysis using principal component analysis (PCA). This study confirms that the five-stage maturity index has accurately classified the maturity stages in the green plums, how maturity stages can be described with physical parameters and the specific changes that occur between each stage of the maturity process. This study has concluded that green plum is a climacteric fruit and suggest that further studies exploring these characteristics could increase its commercial potential. This report provides valuable characteristics of the green plums as potential products for Indigenous agribusinesses and the food industry.