Non-Destructive Estimation of Mechanical and Chemical Properties of Persimmons by Ultrasonic Spectroscopy

Figures & data

FIGURE 1 Diagram of the ultrasonic measuring system.

TABLE 1 Morphological properties of the tested persimmon samples

	cv. Karaj		cv. Shomali
	Mean	Std. dev.	Mean	Std. dev.
Mass (g)	151.25	15.04	173.41	16.34
Length (mm)	44.50	3.16	46.86	2.14
Diameter (mm)	67.08	2.47	72.19	2.03
Shape index	0.66	0.03	0.65	0.02

FIGURE 2 Changes of modulus of elasticity and rupture force in “Shomali;” A: and “Karaj;” B: persimmons during storage time. Error bars show one standard deviation from the mean.

FIGURE 3 Changes of ultrasonic velocity and attenuation in “Shomali;” A: and “Karaj;” B: persimmons during storage time. Error bars show one standard deviation from the mean.

FIGURE 4 Correlations between ultrasonic velocity and modulus of elasticity for Shomali (top left) and Karaj (top right) cultivars and between attenuation and modulus of elasticity for Shomali (bottom left) and Karaj (bottom right) cultivars. The solid line is the regression line.

FIGURE 5 Correlations between ultrasonic velocity and rupture force for Shomali (top left) and Karaj (top right) cultivars and between attenuation and rupture force for Shomali (bottom left) and Karaj (bottom right) cultivars. The solid line is the regression line.

TABLE 2 Regression equations for predicting the mechanical and chemical properties of persimmon fruits from ultrasonic velocity and attenuation

		Constant values of model
Cultivar	Model	k1	k2	k3	R^2	RMSE	MPE
Shomali	E = k1V + k2α + k3	0.009	–1.195	1.283	0.826	0.231	6.843
	Fr = k1V + k2α + k3	0.179	–21.489	17.678	0.893	3.683	2.663
	SSC = k1V^2 + k2V + k3	0.0006	–0.2991	53.432	0.931	0.519	–1.095
Karaj	E = k1V + k2α + k3	0.009	–1.361	1.206	0.861	0.217	5.476
	Fr = k1V + k2α + k3	0.185	–20.459	10.457	0.837	3.849	4.218
	SSC = k1V^2 + k2V + k3	0.0011	–0.5246	77.328	0.987	0.851	–4.650

E, F_r, SSC, V, and α are the modulus of elasticity, rupture force, soluble solids content, ultrasonic velocity, and attenuation coefficient, respectively;

k₁, k₂, and k₃ are coefficients or constant values;

R² is coefficient of determination;

RMSE: root mean square error; MPE: mean percentage error.

FIGURE 6 Scatter plots of measured versus predicted values of mechanical properties obtained by linear model: modulus of elasticity of Shomali (top left) and Karaj (top right) cultivars; rupture force of Shomali (bottom left) and Karaj (bottom right) cultivars. The diagonal black line represents the perfect prediction line.

FIGURE 7 Changes in soluble solids content in persimmons during storage time. Error bars show one standard deviation from the mean.