MASS and surface area modeling of bergamot (citrus medica)

Introducción

MASS and surface area modeling of bergamot (citrus medica) fruit with some physical attributes

ABSTRACT

In this study mass and surface area of bergamot fruit were predicted with using different physical characteristics in linear models classified as follows 1 single or multiple variable regressions of bergamot dimensional characteristic 2 single or multiple variable regressions of bergamot projected area 3 single regression of bergamot mass and surface area based on measured (actual) volume and volumes of shape assumed (oblate spheroid and ellipsoid )and 4 single regression of bergamot surface area based on mass. The results showed that all of mass and surface area models area satisfactorily appropriate models. In the first classification of mass modeling the lowest determining coefficients were as r´2 = 0.87 and r´2 = 0.88 based on length and width respectively, while all the other determining coefficients were higher than r´2=0.90. the highest determining coefficient in all mass models was obtained based on actual volume as r´2.99, based on the results , all determining coefficients for surface area modeling were higher than r´2=0.92. The highest determining coefficient in all models was obtained as r´2 =1.0 for some combinations of projected areas.

Keywords: bergamot, citrus, fruit, jahrom, physical, attributes, grading, peeling.

Nomenclature

Length First projected area

Width Second projected area

Thickness Third projected area

Mass Geometric mean diameter

Measured volume Surface area

Volume of oblate spheroid Regression coefficient

Volume of ellipsoid Determining coefficient

INTRODUCTION

Bergamot (citrus medica) is a species of citrus fruit and is one the important horticultural products of Iran . its tree is called citrus Bergamia . Bergamia is an evergreen tree ( like other trees of this family ). Bergamot is characterized with its thick skin around it .bergamot skin consists of albedo ( protuberances) and flevedo (pulp).

Bergamot outer skin (albedo) has a bitter taste and should be detached in food production the albedo is initially green and as the fruit ripens, becomes yellow. Usually before the yellow stage, the crop is harvested in Iran . The flevedo (pulp) is white in both green and yellow stage of the albedo and is used in jam production and also in medical applications.

Bergamot oil has many therapeutic properties as an antiseptic. Antibiotic anti- spasmodic and antidepressant. bergamot oil is ideal way to remedy skin infections, nervous eczema , stress , depression , anorexia , emotional fear , and tension . Bergamot meat is edible and very sour and can be used instead of lemon juice or in making various pickles. In addition, bergamot skin (pulp) as dried fruit is exported to many countries. Dried skins area used in jam production in seasons that fresh fruit is not available

Most of the methods employed in the processing of agricultural products in Iran like bergamot area still traditional. There develop appropriate technologies for their processing . the development of the technologies will require the properties of these products.

There are instances in which it is desirable to determine relationships among fruit physical attributes. for example. Fruits are often graded by size, but it may be more economical to develop a machine which grades the fruit by weight. Grading fruit based on weight is important in packing and handling and provides suitable packing patterns. The different grading systems require different fruit sizing based on particular parameters. Nearly all fruit and vegetables are grade for quality when delivered for processing or for the fresh markets. In nearly all cases raw product grades area based on weight . shape and physical dimensions are important in screening solids to separate foreign materials and in sorting and sizing of fruit and vegetables . size and shape determine how many fruit can be placed in shipping containers or plastic bags of give size. Peeling is an efficient process for citrus fruit , too . immersing the products to be peeled in a treating solution is one method of peeling agricultural products having skins . the albedo of the fruit is weakened by releasing the vacuum or changing pressure and the citrus peel can be readily removed. amount of required treating solution depends on fruit surface area . also volumes and surface areas of solids must be known for accurate modeling of heat and mass transfer during cooling and drying.

The regression analysis was used by Chuma et al (1982) to develop equations for predicting volume and surface area. They used the logarithmic transformation to develop equations for wheat kernels at moisture content of 15% ( dry basis ) . Frequently, the surface area of fruit is determined based on its diameter or weight. Knowing the diameter or weight of fruit , its surface area may be calculated using empirical equations . or find from an appropriate plot . mass grading of fruit can reduce packaging and transportation cost , and also may provide an optimum . by packaging configuration . Sizing by weighing mechanism is recommended for the irregular shape product . determining relations ships between mass and dimensions and projected areas may be useful and applicable . in weight- sizing machines , individual fruits are carried with cups or trays that may be linked together in a along the conveyor , the supports area engaged with triggering mechanisms which allow the trays to dump contents , if there is sufficient weight . successive triggering mechanisms are set to dump the tray contents at lower weights . if the density of the fruit is constant , the weight-sizing machine sorts the fruits by volume . the sizing error will depend upon the correlation between weight an volume .

Many researches have conducted to find physical proprieties of various types of agricultural products . topuz et al (2005) investigate and compared several properties of four orange varieties . keramat jahromi et al (2007) investigated some physical properties of date . They determined dimensions and projected areas by using image processing technique . Owolarafe and shotonde (2004) investigated some physical properties of fresh okro fruit useful in designing of an okro slicer, chopper and /or grater. In the case of mass modeling . tababataeefar et al (2000) determined models for predicting mass of Iranian grown oranges . in another study . tabatabaeefar (2002) determined physical properties of common varieties of Iranian grown potatoes and the relationships among their physical properties of common varieties of Iranian grown potatoes and the relationships among their physical attributes . lorestani and tabatabaeefar (2006) determined models for predicting mass of kiwi fruit based on . dimensions , projeted areas perpendicular to the diameters and volumes (measured volume and volumes of supposed shape). Also many studies have been reported on the physical properties of agricultural products such gumbo fruit (akar and aydin, 2005), pear (wang 2004), onion and apple.

The objective of this research was determine the optimum bergamot mass and surface area models based on bergamot physical properties . this information could be used to design and develop sizing and peeling systems.

2. MATERIALS AND METHODS

Bergamot samples were directly select randomly from a garden in Jahrom which is one of the most important horticultural centers in south of Iran .the fruits were transported to physical laboratory of biosystems faculty of university of Tehran . the experiments were carried out in three days at laboratory temperature ranged 25 to 29 centigrade .Bergamot moisture contents were 84.90% w.b. for peel and 87.34% for its meat.

Linear dimensions , I, e , length, width and thickness and also projected areas , were determined by image processing method . in order to obtain dimensions and projected areas, winarea_ut_06 system comprises following components:

1. Sony photograph camare model ccd-trv22e.

2. 2. Device for preparing media to taking a picture.

3. Card capture named winfast model dv 2000

4. Computer software programmed with visual basic 6.0

Capture images from the camera are transmitted to the computer card which works as an analog to digital converter, digital images are then processed in the software and the desired user needs are determined . total errors for those objets were less than 2%

Figure 2. win area

This method have been used and reported by several researchers from figure 3 l,w and t are perpendicular dimensions of the fruit namely length , width and thickness and Pl,Pw and Pt are the projected areas taken along these three mutual perpendicular axes.

Figure 3. three major dimensions and projected areas of fruit

Mass(g) of each fruit was determined with an electronic balance with an accurary of 0.0’1 g .Actual volume was measured by the water displacement method.

Geometric mean diameter and surface area were calculated with using the equations 1 and 2 respectively as reported by mohsenin (1986) and kabas et al. (2006)

(1)

(2)

In order to estimate mass and surface area models of bergamot, the following models were considered:

1. Single or multiple regressions of bergamot dimensional characteristics: length (L), width (W) and thickness (T).

2. Single or multiple variable regressions of bergamot projected areas.

3. Single regression of bergamot mass and surface area based on measured (actual) volume.

4. Single regression of bergamot surface area based on mass.

In case of

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