A new method developed to characterize the 3D microstructure of frozen apple using X-ray micro-CT. (November 2017)

• Record Type: Journal Article
• Authors: Vicent, Victor; Verboven, Pieter; Ndoye, Fatou-Toutie; Alvarez, Graciela; Nicolaï, Bart
• Is Part Of: Journal of food engineering. Volume 212(2017)
• Page Start: 154
• Page End: 164
• Publication Date: 2017-11
• Subjects: Apple -- Freezing -- Ice crystals -- X-ray micro-CT -- Image analysis -- 3D microstructure; Food industry and trade -- Periodicals; Food -- Analysis -- Periodicals; Aliments -- Industrie et commerce -- Périodiques; Aliments -- Analyse -- Périodiques; Aliments -- Recherche -- Périodiques; 664.005
• DOI: 10.1016/j.jfoodeng.2017.05.028
• Languages: English
• ISSNs: 0260-8774

Abstract

Abstract: Non-destructive imaging techniques have become indispensable to improve insights into the microstructural changes occurring in fruit tissue during freezing. Here, apple cortex tissue samples were frozen using different freezing rates: (i) slow freezing (2.0 °C per min.), (ii) intermediate freezing (12.6 °C per min.) and fast freezing (18.5 °C per min.). Temperature-controlled X-ray micro-CT was optimized and then applied to visualize and quantify the 3D microstructure and ice crystal distribution at a pixel resolution of 3.8 μm. Ice crystal size distributions with mean equivalent diameters of about 41 ± 3.5 μm, 55 ± 7.4 μm and 71 ± 9.6 μm were obtained for the fast, intermediate and slow freezing rates, respectively. A new imaging methodology was developed and validated to allow segmentation of the ice crystals in frozen apple tissue using the X-ray attenuation coefficients of the reference model samples, i.e. frozen pure water and concentrated apple juice. Highlights: First study of the full 3D microstructural changes of apple tissue during freezing. X-ray μCT was applied to study the 3D microstructural changes during freezing. Different freezing methods show significant difference in the 3D microstructure of the frozen apple tissue. A new method to characterize the ice crystals and the 3D microstructure in plant-based products.