Non-destructive quantification of pomegranate internal quality structures using X-ray computed tomography

Increasing interest in pomegranate fruit has coincided with an increasing consumer demand for consistent supply of safe, nutritious and traceable food products. This demand for quality-assured fruit has spurred the need to develop innovative non-destructive techniques for quality assessment, based on both external and internal quality attributes. In this study, X-ray computed tomography (CT) was investigated for non-invasive characterization and volume quantification of edible (arils) relative to non-edible (albedo) fractions of intact pomegranate fruit. The study was conducted using 'Shani-Yonay' cultivar. X-ray tomograms were acquired using a V|Tome|X L240 commercial X-ray CT system based on X-ray radiation generated from a source voltage of 200 kV and the electron current set at 100 µA. Two-dimensional (2-D) radioscopic images were acquired with a microfocus direct X-ray tube. These 2-D images were used to reconstruct three-dimensional images to quantify volumes occupied by air spaces, albedo, and arils, using image-processing software. The X-ray CT calculated volumes for these fractions were 7.8, 167.3, and 182.1 mL, estimated to respectively contribute 2.2, 46.9 and 50.9% of the total fruit volume. Destructive validation data were similar to X-ray CT calculated data, with volumes for albedo and arils of 158.3 and 162.0 mL, respectively, contributing 46.0 and 47.3% of total volume. The remaining 6.7% of total fruit volume in destructive data was due to air spaces, stem end and calyx. This study demonstrated the capability of X-ray CT as a potential technique to non-destructively characterize structural distribution and quantify volumes of edible to non-edible portions of pomegranate fruit.