Instrumental Textural Properties of Mango (cv Nam Doc Mai) at Commercial Harvesting Time

Figures & data

Figure 1 Typical force-deformation curve obtained from the plate compression relaxation test and recovery test. Deformation (mm) at maximum force (ΔF) = ΔD; maximum force (N) = ΔF; ; ; ; energy of absorption (mJ) = AreaOAC-AreaBCD; .

Figure 2 Typical force-deformation curve obtained from the puncture test. Rupture force (N) = F_r; deformation at the rupture point (mm) = D_r; toughness (mJ) (energy absorbed before rupture point) = area under the curve from the origin to point (0, D_r); ; ; ; bioyield force = F_b (N); penetration force in the flesh (the average of measured forces after rupture point) (N); penetrating energy in the flesh (mJ) = dotted area obtained by the sum of the areas under the curve.

Table 1 The interpretation of instrumental texture properties obtained from the flat plate compression test and puncture test

Instrumental texture properties	Unit	Interpretation
Flat plate compression test
Deformation at maximum force	mm	Deformation of fruit at maximum force defined for the test.
Initial firmness	N/mm	Resistance to deformation under small load at the beginning of the test, in this case 2 N.
Average firmness	N/mm	Resistance to deformation under maximum load at the beginning of the test, in this case 20 N.
Energy of absorption	mJ (N mm)	Work or energy that fruit obtained to deform permanently.
Relaxation		Ability of the fruit to release its stress.
Relaxation force	N	The level the force is reduced to from the initial applied force (maximum force) during relaxation time.
Relaxation ratio	decimal	The amount that the stress is relaxed.
Recovery ratio (degree of elasticity)	decimal	Capability of the fruit to recover from deformation after removing the load, indicating the elasticity of the fruit.
Puncture test
Initial hardness	N/mm	Stiffness or rigidity of fruit.
Average hardness	N/mm	Resistance to deformation under load until the point of sudden fracture.
Deformation at rupture point	mm	Deformation of fruit from the initial state until rupture point.
Rupture force	N	The force necessary to penetrate the skin of the intact fruit.
Bioyield force	N	The force that breaks the initial cell under the skin when the skin is not yet broken.
Toughness	mJ (N mm)	Work or energy required to cause rupture through the skin.
Apparent modulus of elasticity	MPa (N/mm^2)	Stiffness or rigidity of fruit.
Penetrating force in the flesh	N	The force necessary to penetrate the flesh of the fruit.
Penetrating energy in the flesh	mJ (N mm)	Work or energy required to penetrate the flesh of the fruit to a specific depth.

Figure 3 Average force-time curve of the plate compression test of mango at different sizes. (Number of samples = 18, 20 and 20 fruit for large, medium and small sizes, respectively.)

Figure 4 Average force-deformation curve of the puncture test of mangoes at different sizes. (Number of samples = 20, 20 and 20 fruit for large, medium and small sizes, respectively.)

Table 2 Instrumental texture properties of mango fruit at different size for export

	Fruit size
Instrumental texture properties	Large	Medium	Small
By plate compression test
Initial firmness (N/mm)	12.9 ± 2.4b	11.2 ± 1.1a	10.1 ± 1.3a
Average firmness (N/mm)	19.3 ± 3.4b	16.9 ± 1.8a	15.1 ± 1.4a
Deformation at max force (mm)	1.1 ± 0.2a	1.2 ± 0.1b	1.3 ± 0.1c
Energy of absorption (mJ)	4.8 ± 0.8a	5.6 ± 0.8b	6.3 ± 0.6c
Relaxation force (N)	16.0 ± 0.2b	15.8 ± 0.2a	15.9 ± 0.1ab
Relaxation Ratio	0.20 ± 0.01b	0.21 ± 0.01a	0.21 ± 0.01a
Recovery ratio	0.74 ± 0.02b	0.72 ± 0.02a	0.71 ± 0.02a
By puncture test
Initial hardness (N/mm)	6.4 ± 1.2b	6.0 ± 0.6b	5.1 ± 0.7a
Average hardness (N/mm)	10.0 ± 1.0c	9.3 ± 0.8b	8.5 ± 0.7a
Deformation at rupture point (mm)	2.8 ± 0.3a	3.0 ± 0.2a	3.2 ± 0.3b
Rupture force (N)	27.6 ± 1.2a	27.6 ± 2.0a	27.5 ± 2.0a
Toughness (mJ)	36.1 ± 4.5a	39.0 ± 4.7ab	40.9 ± 4.8b
Apparent modulus of elasticity (MPa)	3.2±0.6b	3.00±0.3b	2.6±0.3a
Penetrating force in flesh (N)	10.6 ± 1.1a	10.8 ± 1.9a	9.9 ± 1.3a
Penetrating energy in flesh (mJ)	106 ± 11a	108 ± 19a	99 ± 13a
Data are mean values of 20 fruit, with the standard deviation. Values with different letters in each row are significantly different by least significant difference (LSD) at p = 0.01.