Detection and monitoring of internal browning development in ‘Fuji’ apples using MRI

• Published in: Postharvest biology and technology 2001-05, Vol.22 (2), p.179-188
• Main Authors: Gonzalez, Juan J, Valle, Rosa C, Bobroff, Serge, Biasi, William V, Mitcham, Elizabeth J, McCarthy, Michael J
• Format: Article
• Language: English
• Subjects: Agronomy. Soil science and plant productions; Biological and medical sciences; Controlled atmosphere; Economic plant physiology; Food industries; Fructification, ripening. Postharvest physiology; Fruit and vegetable industries; Fruit quality; Fundamental and applied biological sciences. Psychology; Growth and development; Internal browning; Magnetic resonance imaging (MRI); MR image contrast; ‘Fuji’ apples ( Malus domestica Borkh.)
• ISSN: 0925-5214; 1873-2356
• DOI: 10.1016/S0925-5214(00)00183-6

Magnetic resonance imaging (MRI) experiments were used to detect and monitor the progression of internal browning (IB) in Fuji apples ( Malus domestica Borkh.). The apples were stored in two different controlled atmosphere (CA) conditions: 3% CO 2 at 0°C and 18% CO 2 at 20°C. The apples stored under 18% CO 2, were imaged at 1, 3, 5, 7 and 9 days. Apples stored under 3% CO 2 were imaged once a week for the first 7 weeks and then every 2 weeks until the 12th week. Three distinct regions were identified in the MR images of apples with internal browning: normal, light brown and dark brown tissue. Light brown regions, more prominent in apples stored in 3% CO 2 at 0°C, had a lower signal intensity than normal tissue because of lower proton density (PD) and smaller transverse relaxation times ( T 2). Dark brown regions predominated in apples stored in 18% CO 2 at 20°C and displayed higher signal intensity than the normal apple tissue because of larger T 2 values. The speed of image acquisition was improved from 5.5 min to 20 s, by reducing the spatial resolution of the images. Both types of IB were detected by images acquired using coarse spatial resolution and correlated well to the IB detected by the images acquired using fine spatial resolution.