Estimation of Changes in Mechanical and Color Properties from the Weight Loss Data of “Shine Muscat” Fruit during Storage

Abstract

“Shine Muscat” fruit is a table grape commonly consumed cultivar in Japan; however, the storage characteristics have not been investigated, especially physical properties. The objective of this study was to clarify changes in weight loss, mechanical, and color properties of Shine Muscat fruit during storage and the relationships between them. The storage tests were performed at 15°C under two relative humidity (RH) conditions, i.e., RH 95% and RH 40%. The weight loss of fruit was calculated from the mass changes during storage. The mechanical properties—stress, strain, and elasticity—at the break point were examined by compression tests. The color properties, color differences (ΔE), and chroma (C) were calculated from L∗a∗b∗ scale parameters. The breaking stress did not reflect changes in the mechanical characteristics of samples during storage. Weight loss was highly correlated with the breaking strain and elasticity, ΔE, and C. In addition, the physical properties could be estimated from weight loss data (R2 = 0.81–0.94). We showed the changes in weight loss and other physical properties and proposed equations to estimate the physical properties based on weight loss data. The equations indicated the importance of inhibiting the weight loss to maintain the quality and could be used as a nondestructive and easy method for assessment of storage characteristics of Shine Muscat fruit.