The consumption of melon (Cucumis melo L.) has been, until several years ago, regional, seasonal and without commercial interest. Recent commercial changes and world wide transportation have changed this situation. Melons from 3 different ripeness stages at harvest and 7 cold storage periods have been analysed by destructive and non destructive tests. Chemical, physical, mechanical (non destructive impact, compression, skin puncture and Magness- Taylor) and sensory tests were carried out in order to select the best test to assess quality and to determine the optimal ripeness stage at harvest. Analysis of variance and Principal Component Analysis were performed to study the data. The mechanical properties based on non-destructive Impact and Compression can be used to monitor cold storage evolution. They can also be used at harvest to segregate the highest ripeness stage (41 days after anthesis DAA) in relation to less ripe stages (34 and 28 DAA).Only 34 and 41 DAA reach a sensory evaluation above 50 in a scale from 0-100

Agulheiro Santos, Ana Cristina

Barreiro Elorza, Pilar

Ruiz-Altisent, Margarita

Archivo Digital UPM

Storabelity of melon for different ripeness stages at harvest. Selection of instrumental procedures for quality assessment.

Servicio de Coordinación de Bibliotecas de la Universidad Politécnica de Madrid

AgEng EurAgEng 
Paper no: 98-F-072 
Title: 
STORABELITY OF MELON FOR DIFFERENT RIPENESS STAGES AT 
HARVEST. SELECTION OF INSTRUMENTAL PROCEDURES FOR 
QUALITY ASSESSMENT. 
Authors: 
Agulheiro Santos, A.C.1}; Barreiro Elorza, P.2); Ortiz C.2); Ruiz-Altisent, M.2) 
1) Fitotecnia Department, University of Evora, Portugal. 
Email: acsantos@uevora.pt 
2) Physical Properties Laboratory, Rural Eng. Department, ETSIA, University Politecnica 
Madrid. Spain 
Email: labpropfis@iru.etsia.upm.es 
Summary: 
The consumption of melon (Cucumis melo L.) has been, until several years ago, 
regional, seasonal and without commercial interest. Recent commercial changes 
and world wide transportation have changed this situation. 
Melons from 3 different ripeness stages at harvest and 7 cold storage periods 
have been analysed by destructive and non destructive tests. Chemical, physical, 
mechanical (non destructive impact, compression, skin puncture and Magness-
Taylor) and sensory tests were carried out in order to select the best test to assess 
quality and to determine the optimal ripeness stage at harvest. Analysis of 
variance and Principal Component Analysis were performed to study the data. 
The mechanical properties based on non-destructive Impact and Compression 
can be used to monitor cold storage evolution. They can also be used at harvest 
to segregate the highest ripeness stage (41 days after anthesis DAA) in relation to 
less ripe stages (34 and 28 DAA).Only 34 and 41 DAA reach a sensory 
evaluation above 50 in a scale from 0-100. 
STORABILITY OF MELON FOR DIFFERENT RIPENESS STAGES AT 
HARVEST. SELECTION OF INSTRUMENTAL PROCEDURES FOR 
QUALITY ASSESSMENT. 
Agulheiro Santos, A.C.1} 
Barreiro Elorza, P.2) 
Ortiz C.2) 
Ruiz-Altisent, M.2) 
1) Fitotecnia Department, University of Evora, Portugal. 
Email: acsantos@uevora.pt 
2) Physical Properties Laboratory, Rural Eng. Department, ETSIA, University 
Politecnica Madrid. Spain 
Email: labpropfis@iru.etsia.upm.es 
INTRODUCTION 
The consumption of melon (Cucwnis melo L.) has been, until several years ago, 
regional, seasonal and without commercial interest. Recent commercial changes and 
world wide transportation have changed this situation and countries from meridional 
Europe have discovered that they can easily provide these fruits whenever they are able 
to guaranty quality. 
First references on the post-harvest quality of melon come from the 80's (Andre, 1982; 
CEMAGREF, 1982; Dull, 1989). In these studies recommendations are given about 
standard destructive tests for quality assessments as Solid Soluble Content (SSC) and 
Magness-Taylor (MT) Firmness. There are specific performance of MT for melons and 
reference values for several commercial quality such as excellent (refractometric index 
> 12, Magness-Taylor firmness between 0,5 and 1,5 Kg/0,5 cm") and good 
(refractometric index > 9, Magness-Taylor firmness between 0,5 and 1,5 Kg/0,5 cm2). 
New indications on destructive tests performed on melon come from Mizrach et al 
(1989), and Cardenas-Weber et al (1991), where the elasticity modulus on fruit probes 
are performed. Mizrach et al (1989) demonstrated that there is a strong variation of the 
elasticity modulus depending on the depth at which the fruit probe is extracted 
obtaining typical strain-stress curves for outer, middle and inner flesh of the melon. The 
relationship between the elasticity modulus and attenuation coefficient (r= 0,787) of 
ultrasonic excitation suggest that this measurements could be used for non-destructive 
internal quality assessment of the melon. The work of Cardenas-Weber et al (1991), on 
the elasticity modulus was oriented to the applicability of a gripping robot, in order to 
know the maximum force which could be applied to the melon without danger of 
bruising. 
Besides the work of Mizrach et al (1991) on the non-destructive internal quality 
assessment of melons, new techniques as impact and acoustic impact response have 
been carried out on melon. Non-destructive impact have been used by our research 
group Agulheiro Santos (1991), Agulheiro Santos and Ruiz Altisent (1993), with good 
perspectives for melon ripeness assessment, based on a previous development (Chen et 
al, 1985 and Garcia, 1988b) already tested for other fruits types: apple and pear, 
peaches, apricots, avocado (Jaren et al, 1992, Correa et al, 1993, Barreiro e Ruiz-
Altisent, 1993). 
Acoustic impact response has been widely studied by Sugiyama et al (1994) showing a 
high correlation between the transmission velocity of the acoustic impact and the fruit 
firmness measured as penetration resistance (N) with 3 mm rod (r=0,832). Finally, in 
1998 a portable prototype based on the acoustic impact response has been presented by 
Sugiyama et al (1998) in order to perform field measurement of the ripeness stage of 
melons. 
OBJECTIVES 
The main objectives of this work are: 
• To study the main sources of variation in the mechanical, physical and chemical 
properties of melons during cold storage; 
• To select the best tests to assess quality/ripeness 
• To determine optimal ripeness stage at harvest in relation to sensory evaluation 
MATERIAL AND METHODS 
Fruits belonged to Cucumis melo L. cv. Gustal. A factorial design concerning ripeness 
stage at harvest (3 modalities) and cold storage period (7 modalities) has been used. 
Ripeness stages consisted of 1) a complete ripe group of fruits (41 days after anthesis 
DAA), 2) an unripe but very near from the ripe stage (34 DAA) and 3) an absolutely 
unripe (28 DAA) sample. 
The fruits were stored at 6°C of temperature and 90% of R.H.. At predetermined days 
(3, 8, 15, 21, 27 and 31) samples were removed from cold storage and analysed. Each 
sample covered 4 fruits, so a total amount of 84 melons were used. 
The tests carried out can be summarised as follows: 
/ - Physical: Observation of external and physical characteristics such us: diameter, 
length, weight and weight loss (weightl), volume, and flesh width (fleshw). 
2 - Mechanical 
Non destructive Impacts, a spherical mass with 47,292 g of weight indent the fruit at 
the height of 12 cm. The maximum force (IMF), maximum deformation (IMD), 
permanent deformation, absorbed energy (IME) and impact duration (ITT) are extracted 
from the deceleration data registered by an accelerometer. 
Compression, using a 30mm diameter sphere until 3mm of deformation are reached . 
Force at 3mm is measured (CF3). 
Skin Puncture, using a cylindrical rod, 0.5 mm diameter. Test is performed until a 
maximum of 8 mm of penetration is reached. The maximum puncture force (PMF), the 
puncture deformation (PD) and the remaining force after skin rupture, named as stable 
puncture force (PFS), are measured. 
Magness-Taylor Test, using a 8mm diameter rod, the test is performed in the mesocarp 
of halved fruits at 1.5 cm depth from the skin. A maximum penetration of 8 mm is 
used as endpoint. The maximum force (MTFIR), the deformation at the maximum force 
(MTD) and the force at 3mm (MT3) and 8 mm (MT8) are measured. 
3 - Chemical: Solid Soluble Content, in fruit juice using a refractometer at Magness-
Taylor site (Brixpar) and average fruit measurement (Brixtot). 
4 - Sensory: Sensorial Evaluation with a pool of 8 people maximum trained for this 
commodity (Global Hedonic evaluation). 
RESULTS AND DISCUSSION 
Sources of variation affecting mechanical, physical and chemical parameters 
Several mechanical tests are more related to the changes that occur during cold storage 
than to the ripeness stage at harvest (F value in ANOVA analysis higher for "storage 
duration" than for "days of anthesis"). That is the case for : 
• Non destructive impact: Maximum force (Fstorage=42.05), Impact duration 
(Fstorage=35.31) 
• Non Destructive Compression : Force at 3mm (Fstorage=54.22) 
• Magness-Taylor firmness : Force at 3mm (Fstorage=55.28) 
The loose of weight is also the physical parameter showing the highest relationship with 
changes occurred under cold storage (Fstorage=106.67). 
The ripeness stage at harvest is mainly related to the chemical test such as Soluble Solid 
Content (F value for "days of anthesis" = 32.82 when compared to 3.78 for "storage 
duration"). Some mechanical parameters also relate mainly to the ripeness stage at 
harvest as the Maximum Force (MFP, Fanthesis=50.80) and the Stable Force (StFP, 
Fanthesis=46.10) both belonging to the skin puncture test. This is also the case for most 
of the physical parameters: diameter (Fanthesis=16.12 ), lenght (Fanthesis= 11.86), 
volume (Fanthesis= 16.44). 
The highly significant effect obtained in the interaction between "days after anthesis" 
and "cold storage duration" for several mechanical parameters: impact maximum force 
(F interaction=6.46, see first row in Figure 1), impact duration (F interaction^. 19), 
Magness-Taylor firmness (F interaction=9.83) and force at 8mm (F interaction=9.41), 
and force at 3mm deformation (F interaction=8.74) under non destructive compression, 
indicates a differential behaviour of melons under storage due to differential harvest 
conditions. 
A Principal Component Analysis has been carried out using a pool of 14 physical, 
mechanical and chemical parameters. The first Principal Component, explaining a 43 % 
of the total variance,cis composed by mechanical tests such as Maximum Impact Force 
(IMF), Maximum Impact Deformation (IMD), Impact duration (ITT), maximum 
deformation at Skin Puncture (PMF), Force at 3mm under Compression (CF3), and a 
physical parameter as Loose of Weight (weightl, see Figure 2). All of them showing a 
very high correlation one-another. The representation of individuals under this Principal 
Component shows that this Factor mainly relates with the changes occurred under cold 
storage as shown through the ANOVA. The three different ripeness stages at harvest 
exhibit distinct behaviors during cold storage; the less ripe fruits were those having a 
wider change (See figure 3). In all three ripeness stages at harvest (28, 34 and 41 DAA) 
there is a sigmoid behavior during cold storage, however the inflexion point and range 
of variation of the sigmoids differs in all three cases. This is also confirmed by a 
significant effect in the ANOVA of the interaction "Storage Period" - "Days After 
Anthesis" in the variables associated with the first PC. 
The Solid Soluble Content (SSC) is related to the Second Principal Component (24% of 
total explained variance) also highly independent from the parameters forming the First 
Principal Component as the SSC increases for higher number of days after anthesis at 
harvest and remains fairly constant (see second row in Figure 1). 
The use of the Principal Components (PC) instead of the individual parameters allows 
to obtain a more smooth information of the changes occurred in the melons along the 
cold storage period, (compare first row in Figure 1 and Figure 3). 
M 
g 
1 W 
M 
x-xi 
-
1
- s^^$ 
0 3 8 15 11 27 31 « 
COLO tTORAGE AT*" C 
34DAA 
Impact Maximum Force 
J i 15 2\ 21 
COLD STORAGE AT S"C (Ciys} 
48DAA 
0 3 8 ' S 
COLD STORAGE > 
_J_: j ±S"jJ 3ev 
- L j L ~ ±SM Err. 
I I 27 31 ' Mea" 
X 
GD — 8 7 
28 
6°e (Days) 
DAA 
0 3 8 15 21 27 31 
COLD STCKAOE AT 5*C &W&Z 
34 DAA 
Solid Soluble Content 
0 3 9 15 21 27 31 
COCO STORAGE AT 6" JJ»f9l 
48 DAA 
COLD STORAGE a! "6 C {Days) COLD STORAGE AT *6 C (Bays) COLD STORAGE AT 6" C (Days) 
28 DAA 34 DAA 
Global Hedonic Evaluation by consumers 
48 DAA 
Figure 1. Evolution of selected mechanical, chemical and sensory parameters during cold storage for 3 
different ripeness stages at harvest 
Selection of tests for quality assessment 
The chemical test along with the skin punction are the tests enabling to establish the 
ripeness stage at harvest. However other mechanical test as non destructive impact and 
compression allow to segregate at harvest the most ripe melons (41 DAA) when 
compared with the others ripeness stages (34 and 28 DAA) and simultaneously to 
follow changes during storage. 
Optimal ripeness stage at harvest in relation to sensory quality 
When comparing SSC and mechanical properties against the sensory evaluation (see 
third row in Figure 1) it is clear that the Global Hedonic Evaluation is based on the 
values of SSC while the mechanical properties are only important to decide about 
quality when the values of SSC are very low. The 28 DAA never reach a Global 
Hedonic Evaluation above 50 in a scale 0-100 in spite of 34 and 41 DAA samples 
which reach 75 and 84 respectively. 
The ripeness stages referred in this work as 34 and 41 DAA are therefore the most 
adequate to in relation to sensory quality. 
Variable 
IMF 
IME 
ITT 
MTFIR 
MT8 
PMF 
PFS 
CF3 
Brixtot 
weightl 
Diameter 
Volume 
MS Effect 
F 
P-level 
1 
Days after 
anthesis 
596.425 
25.00407 
0.00 
0.000056 
8.11722 
0.00 
4.35817 
14.16550 
0.00 
240.3767 
35.04213 
0.00 
160.9494 
33.39626 
0.00 
45.64687 
52.79955 
0.00 
2.434983 
46.10055 
0.00 
5.92908 
16.55113 
0.00 
37.80316 
30.60918 
0.00 
1193.393 
14.3277 
0.00 
9.490342 
16.11985 
0.00 
810004.4 
16.44193 
0.00 
2 
Days of cold 
storage 
1003.047 
42.05097 
0.00 
0.000198 
28.77386 
0.00 
10.86455 
35.31340 
0.00 
216.0179 
31.49110 
0.00 
172.4208 
35.77653 
0.00 
8.67996 
10.04007 
0.00 
0.715790 
13.55176 
0.00 
19.42381 
54.22192 
0.00 
3.44391 
2.78853 
0.02 
8885.087 
106.6730 
0.00 
1.997981 
3.39368 
0.01 
250654.6 
5.08793 
0.00 
1x2 
Interaction 
154.207 
6.46486 
0.00 
0.000024 
3.53834 
0.00 
2.51841 
8.18568 
0.00 
67.4349 
9.83067 
0.00 
45.3266 
9.40507 
0.00 
1.24907 
1.44479 
0.15 
0.138229 
2.61704 
0.00 
3.12981 
8.73691 
0.00 
1.44802 
1.17246 
0.32 
207.339 
2.4893 
0.00 
0.652174 
1.10775 
0.37 
37983.5 
0.77101 
0.68 
MS Error 
23.85311 
0.000007 
0.307661 
6.859649 
4.819383 
0.864532 
0.052819 
0.358228 
1.235027 
83.29277 
0.588737 
49264.57 
Degrees 
of 
freedom 
145 
145 
145 
145 
145 
145 
145 
145 
62 
62 
62 
62 
Number of 
Observation 
s 
166 
166 
166 
166 
166 
166 
166 
166 
83 
83 
83 
83 
Cv 
% 
10.91 
5.36 
9.38 
36.34 
36.99 
18.84 
32.22 
20.31 
12.17 
17.07 
4.83 
13.99 
Table 1. ANOVA Analysis (MS effect, F value and p-level) for the chemical, mechanical and physical 
parameters in relation to ripeness stage and cold storage period. 
Factor Loadings 
Extraction: Principal components 
(Marked loadings are > .700000) 
Factor Factor Factor 
1 2 3 
IMF 
IMD 
ITT 
MTFIR 
MTD 
PMF 
PD 
CF3 
WEIGHTL 
FLESHW. 
BRIXPAR 
BRIXTOT 
VOLUM 
Expl.Var 
Prp.Totl 
0.84190846 
-0.89152765 
-0.89966397 
0.45812293 
-0.37945568 
-0.34508127 
-0.8430376 
0.86510441 
-0.81086637 
0.55374117 
0.30059567 
0.25945111 
0.50613127 
5.62306408 
0.43254339 
-0.4769169 
0.29260828 
0.32256285 
-0.51765256 
-0.04494544 
-0.64150632 
-0.21135044 
-0.31660942 
-0.06488877 
0.56097525 
0.8495196 
0.87011139 
0.40042608 
3.2015635 
0.24627412 
0.1126708 
-0.06556573 
-0.10132693 
-0.24315165 
0.55178512 
0.34021494 
0.12758529 
0.13408784 
0.35023255 
0.39696493 
-0.07992433 
-0.08454277 
0.58363439 
1.1752625 
0.09040481 
Figure 2. Principal Component Analysis based on physical, mechanical and chemical parameters. 
-!-U J 
~
L
-
-^ 
r~? "1 
-4^ 
_ 1 _ 
m 
r j L ~ 
• tSVEtl 
• MOD 
COLD STORAGE AT 6" C (Days) COLD STORAGE AT 6° C (Days) COLD STORAGE AT S» C ( Da/5) 
Figure 3. Evolution of the 1st Principal Component for different days of anthesis and cold storage periods. 
CONCLUSIONS 
• The ripeness stage at harvest relates to the chemical properties, which also remain 
fairly constant even they are 31 days of cold storage. 
• The mechanical properties based on non-destructive Impact and Compression can 
be used to monitor cold storage evolution. They can also be used at harvest to 
segregate the highest ripeness stage (41DAA) in relation to less ripe stages (34 and 
28 DAA). 
• Texture evolution along cold storage exhibit a sigmoid behavior for the three 
ripeness stages at harvest. The ripeness stage of 28 DAA shows the worst evolution 
when compared to 34 and 41 DAA. 
• Only 34 and 41 DAA reach a Global Hedonic Evaluation above 50 (75 and 84 
respectively) in a scale from 0-100. 
REFERENCES 
6. 
Agulheiro Santos, A.C.. 1991. Determinacao de Caracteristicas Fisicas em Meloes 
'Branco da Leziria' e 'Piel de Sapo'. Master degree, Instituto Superior de 
Agronomia, Universidade Tecnica de Lisboa. Portugal. 
Agulheiro Santos, A.C. and M. Ruiz Altisent. 1993. Impact Test In Melon (Cucumis 
melo L.). Fruit, Nut and Vegetable Production Engineering. Valencia-Zaragoza, 
Spain. 
Andre, P. et al.,1982. Essais de Conservation de Melons Cantaloup. P.H.M.- Revue 
Horticole, n° 227. 
Barreiro, P. and M. Ruiz-Altisent. 1993. Bruise Susceptibility in Pome Fruits under 
Different Loading and Storage Conditions. Fruit, Nut and Vegetable Production 
Engineering. Valencia-Zaragoza, Spain. 
Cardenas-Weber, M., R. L. Stroshine, K. Haghighi and Y. Edan. 1991. Melon 
Material Properties and Finite Element Analysis of Melon Compression with 
Application to Robot Griping. Transactions of the American Society of Agricultural 
Engineers (ASAE). 34(3): 121-127. 
CEMAGREF, 1982. Mesure de la Qualite Gustative du Melon Type Charentais. 
CEMAGREF.48(1). France. 
Chen, P., S. Tang and S. Chen. 1985. Instrument for Testing Response of Fruits to 
Impact. ASAE paper n°l 85-3537. 
Correa, P., M. Ruiz-Altisent and L. L. de la Plaza. 1992. Physical Parameters in 
Relation to Physiological Changes of Avocato during Ripening (20°C) and Cold 
Storage (6°C) in different Conditions. AGENG92, Paper n° 9211-16. International 
Conference on Agricultural Engineering. Uppsala, Sweden. 
9. Dull, G.G. et al., 1989. Near Infrared Analysis of Soluble Solids in Intact Cantaloup. 
Journal of Food Science, 54 (2): 393-395. 
10. Garcia, C , M. Ruiz Altisent and P. Chen. 1988b. Impact Parameters Related to 
Bruising in Selected Fruits. ASAE, paper n° 88- 6027. 
11. Jaren, C , M. Ruiz Altisent and R. Perez de Rueda. 1992. Sensing Physical Stage of 
Fruits by their Response to Nondestructive Impacts. AGENG 92. Paper n° 9211-13. 
International Conference on Agricultural Engineering. Uppsala, Sweden. 
12. Mizrach, A., N. Galili, G. Rosenhouse and D.C. Teitel. 1991. Acoustical, 
Mechanical, and Quality Parameters of Winter-Grown Melon Tissue. Transactions 
of the ASAE. 34(5):2135-2138. 
13. Sugiyama, J., T. Katsurai, J. Hong, H. Koyama and K. Mikuriya. 1998. Melon 
Ripeness Monitoring by a Portable Firmness Tester. Transactions of the ASAE. 
41(1): 121-127. 
14. J. Sugiyama, K.Otobe, S.Hayashi and S.Usui. 1994. Firmness Measurement of 
Muskmelons by Acoustic Impulse Transmission. Transactions of the ASAE. 
37(4):1235-1241. 


Storabelity of melon for different ripeness stages at harvest. Selection of instrumental procedures for quality assessment.

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