Some Physical properties of Date Fruit (cv. Lasht)

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1 1 Some Physical properties o Date Fruit (cv. Lasht). Keramat Jahromi, A. Jaari, S. Raiee, A. R. Keyhani, R. irasheh, and S.S. ohtasebi Department o Agricultural achinery, Faculty o Biosystems Engineering, University o Tehran Corresponding author. address: mahdikeramat@gmail.com ABSTRACT Knowledge o the physical properties o date ruit is necessary or the design o post harvesting equipment such as cleaning, sorting, grading, kernel removing, and packing. In this study, some physical properties o date (Phoenix dactyliera L.) ruit (cv. Lasht) were determined. Dry-basis moisture content o date ruits ound to be 18.48% (19.60% or pitted dates and 8.69% or their pits). Other results showed that linear dimensions varied rom to 42.60mm in length, to 25.30mm in width, and to 24.40mm in thickness. ean mass and ruit volume was measured as 7.16g and 7.24cm 3, respectively. The projected areas perpendicular to length (P L ), width (P W ), and thickness (P T ) were , and mm 2, respectively. Attempt was made to model date mass by applying dierent physical characteristics as three dierent classiications based on single or multiple variable regressions o dimensions characteristic, projected areas and single variable regression o volume. The results o mass modeling showed that there were no signiicant relations based on dimensions and projected areas while appropriate mass model based on volume was ound to be as: = V , R 2 = The ruit density and pitted ruit density were measured 1.00 and 1.39g/cm 3 while bulk density and porosity were 0.53g/cm 3 and 46.56%, respectively. The geometric mean diameter, sphericity and surace area were obtained as 25.95mm, 0.69, and mm 2, respectively. The mean coeicients o static riction were measured as 0.35, 0.32 and 0.26 on galvanized steel, plywood and glass suraces, respectively. Keywords: Date ruit, physical properties, Lasht, riction, Jahrom 1. INTRODUCTION Date ruit is one o the most important agricultural products o Iran. ost o the date ruit processing methods employed is still traditional. There is a need or a comprehensive study o the physical properties o date to develop appropriate technologies or its processing. The development o the technologies will require the properties o this ruit. It becomes imperative to characterize the ruits with a view to understand the properties that may aect the design o machines to handle their processing. any researchers have conducted experiments to ind the physical properties o various ruits and crops. Tabatabaeear et al. (2000) determined models or predicting mass o Iranian grown oranges. In another study, Tabatabaeear (2002) determined the physical properties o common varieties o Iranian grown potatoes and the relationships among their physical attributes. Topuz et al. (2005) determined and compared several properties o our orange varities. Tabatabaeear and

2 2 Rajabipour (2005) recommended 11 models or predicting mass o apples based on geometrical attributes. Lorestani and Tabatabaeear (2006) determined models or mass modeling o kiwi based on physical attributes. Asoegwu et al. (2006) determined some physical properties o Arican oil bean seeds at 8.73 ± 0.09% moisture content (db) using standard methods as a prelude to obtaining relevant data or the design o tools, equipment, machines and systems or their processing. Keramat Jahromi et al. (2007) determined dimensions and projected areas o date (Barhi variety) by image processing technique. Also many studies have been reported on the physical properties o agricultural crops such as plum (Ertekin et al., 2006) and gumbo ruit (Akar & Aydin, 2005). The objectives o this study is to determine some physical properties o date ruit (cv. Lasht) in order to acilitate the design o some machines or its processing. Also An attempt was made to model date mass based on single or multiple variable regressions o dimensions characteristic, projected areas and single variable regression o volume. Up to date, no detailed study o mass modeling o date ruit has been perormed 2. ATERIALS AND ETHODS In this study, the date ruit was selected rom Lasht cultivar (Fig. 1). From the samples, about 500 ruits were randomly obtained rom a local market in Jahrom (an important city in date production located in the south o Iran). Fig.1. Date samples (cv. Lasht) The ruits were transported, individually to the Physical Laboratory o Biosystems Faculty in the University o Tehran. All experiments were carried out at a temperature range o C in three days. In order to obtain the moisture content, samples were kept in an oven (Iran Khodsaz) or 3 days at 105 C. Weight loss on drying to a inal constant weight was recorded as moisture content by AOAC (1984) recommended method and using the ollowing equation (1): 0 d C = 100 (1) o where C is moisture content (w.b.), 0 is initial mass and d is the inal mass o date ruit (g).

3 3 ass o individual ruit was determined using an electronic balance with a sensitivity o 0.0l g. Fruit volumes were measured by water displacement method. Fruits were weighed in air and allowed to loat in water. Fruits were lowered with a needle into a graduated beaker containing water and the mass o water displaced by the individual ruit was recorded. Finally, ruit densities (g/cm 3 ) were calculated by using the ollowing equation (2) (ohsenin, 1986): a = w (2) a w where and w are ruit and water densities (g/m 3 ); a and w are mass o date in air and water, respectively. The bulk density was determined using the mass/volume relationship (equation 3) (AOAC, 1984; Owolarae et al., 2007) by illing an empty plastic container o predetermined volume and mass with the ruits were poured rom a constant height, and weighed. b = (3) V where b is the bulk density (g/cm 3 ), and V are bulk mass o ruit (g), and the plastic container volume (cm 3 ), respectively. This method was based on the work o Owolarae et al (2007), Fraser et al., (1978) and Suthar et al., (1996). Porosity (ε ) was calculated as the ratio o the dierences in the ruit and bulk densities to the ruit density value and expressed in percentage (Jain and Bal, 1997; Vursavus et al., 2006; Owolarae et al., 2007): b ε = ( ) 100 (4) 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 (irasheh, 2006) was used (Fig. 2). Fig.2.WinArea_UT_06 system WinArea_UT_06 system comprises ollowing components:

4 4 1. Sony photograph camera odel CCD-TRV225E (with resolution o 800*600 pixels) 2. device or preparing media to taking a picture 3. Card capture named Winast model DV Computer sotware programmed with visual basic 6.0 Captured images rom the camera are transmitted to the computer card which works as an analog to digital converter. Digital images are then processed in the sotware and the desired user needs are determined. Total error or those objects was less than 2%. This method have been used and reported by several researchers (Raiee et al., 2006; Keramat Jahromi et al., 2007; Khoshnam et al., 2007). From Fig. 3, L, W and T are perpendicular dimensions o date ruit namely length, width and thickness and P L, P W and P T are the projected areas taken along these three mutual perpendicular axes. Fig. 3.Three major dimensions and projected areas o date ruit Geometric mean diameter (D g ), sphericity ( Φ ) and surace areas (S) were calculated by using the ollowing equations: 1/3 D = (LWT) (5) g Φ = D g L (6) 2. Dg S = π (7) As reported by ohsenin (1986) and Kabas et al. (2006). The coeicients o static riction were obtained with respect to three dierent suraces namely galvanized steel, plywood and glass suraces by using an inclined plane apparatus as described by Dutta et al. (1988). The inclined plane was gently raised and the angle o inclination at which the sample started sliding was read o the protractor with sensitivity o one degree. The tangent o the angle was reported as the coeicient o riction (Dutta et al., 1988): μ = tanφ (8) where, μ is the coeicient o riction and φ is the tilt angle o the riction device. All the riction experiments were conducted in three replications or each surace. 3. RESULTS AND DISCUSSION The average dry-basis moisture content o date ruit samples was ound to be 18.48% (19.60% or pitted dates and 8.69% or their pits). Results showed that mass and volume varied rom 3.99 to 9.95g and rom 3.99 to 10.71g/cm 3 with mean values o 7.16g and 7.24g/cm 3, respectively. Dimensions varied rom to 42.60mm in length, to 25.30mm in width, and to mm in thickness, with average values o 37.82, 22.08,

5 5 and 20.95mm, respectively. The importance o dimensions is in determining the aperture size o machines, particularly in separation o materials as discussed by ohsenin (1986). These dimensions can be used in designing machine components and parameters. For example, it may be useul in estimating the number o ruits to be engaged at a time. The major axis has been ound to be useul by indicating the natural rest position o the ruit. The mean projected areas perpendicular to length, width, and thickness were obtained as , and mm 2, with variation o 292 to 500, 477 to 833 and to 854mm 2, respectively. It was ound that the projected area, perpendicular to thickness, showed higher values than that o other areas. The results o mass modeling based on single or multiple variable regressions o dimensions characteristic, projected areas and single variable regression o measured volume showed that there were no signiicant relations based on dimensions and projected areas, while mass model based on measured volume was obtained as relation: ass = (Volume) , R 2 = Grading ruit based on weight reduces packing and handling costs and also provides suitable packing patterns (Khoshnam et al., 2007). The whole ruit density and pitted ruit density were measured and ound to be between 0.80 to 1.21 and 1.33 to 1.44g/cm 3 and with average values o 1.00 and 1.39g/cm 3, respectively. Bulk density and porosity obtained were ound to be 0.53g/cm 3 and 46.56%, respectively. The geometric mean diameter, sphericity and surace area varied rom to 29.5 mm, 0.63 to 0.74, and to mm 2 while mean values were mm, 0.69, and mm 2, respectively. Also mean coeicient o static riction, on galvanized steel, plywood and glass suraces, were obtained as 0.35, 0.32 and 0.26, respectively. Result o analysis showed that the surace materials had a signiicant dierence (p<0.01) on the static coeicient o riction. The static coeicient o riction on plywood was higher than that on glass and lower than that o galvanized steel surace. This is due to the rictional properties between the ruits and surace materials. These properties may be useul in the separation process and the transportation o the ruits. A summary o results o the determined physical parameters is shown in Table1. Table1. Some Physical properties o date ruit (Lasht cultivar) Properties o date Number o inimum aximum ean Standard observations value value value deviation ass, g Volume, cm Length (L), mm Width (W), mm Thickness (T), mm Projected area along L, mm Projected area along W, mm Projected area along T, mm Fruit density, g/cm Pitted density, g/cm Geometric mean diameter, mm Sphericity, % Surace area, mm Bulk density, g/cm Porosity, %

6 6 Static coeicient o riction Galvanized steel Plywood Glass The physical properties o date ruit were described in order to better design o a speciic machine or post-harvesting operations. 4. CONCLUSIONS 1- The average mass and volume or date (cv. Lasht) were ound to be 7.16g and 7.24cm 3, respectively. 2- The ruit density and pitted ruit density were measured as 1.00 and 1.39g/cm 3, respectively. 3- The bulk density and porosity were 0.53 g/cm 3 and 46.56%, respectively. 4- Linear dimensions ranged rom to 42.60mm in length, to 25.30mm in width, and to 24.40mm in thickness. 5- The mean projected area perpendicular to length, width, and thickness were determined as , and mm 2, respectively. 6- The geometric mean diameter, sphericity and surace area were calculated as mm, 0.69 and mm 2, respectively. 7- The mean coeicients o static riction, on galvanized steel, plywood and glass suraces, were obtained as 0.35, 0.32 and 0.26, respectively. 5. ACKNOWLEDGEENT The authors are grateul to ahdi Ghasemi Varnamkhasti and Kamran Kheiralipour or valuable technical assistance. This Research was inanced by Faculty o Biosystems Engineering, University o Tehran. 6. REFERENCES Akar, R and C. Aydin Some physical properties o gumbo ruit varieties. Journal o Food Engineering 66: AOAC Oicial methods o analysis. 14th edition. Association o Oicial Analytical Chemists, Washington D.C. Asoegwu, S. N., S. O. Ohanyere, O.P. Kanu and C.N. Iwueke Physical properties o Arican oil bean seed (Pentaclethra macrophylla). Agricultural Engineering International: the CIGR Ejournal, anuscript FP Vol. VIII. Demir, F., H. Dogan,. Ozcan and H. Haciseerogullari Nutritional and Physical properties o hackberry (Celtis australis L.). Journal o Food Engineering 54: Dutta, S.K., V.K. Nema and R.K. Bhardwaj Physical properties o grain. Journal o Agricultural Engineering Research 39: Ertekin, C., S. Gozlekci, O. Kabas, S. Sonmez and I. Akinci Some physical, pomological and nutritional properties o two plum (Prunus domestica L.) cultivars. Journal o Food Engineering 75:

7 7 Fraser, B.., S.S. Vermaand and W.E. uir Some physical properties o ababeans. Journal o Agricultural Engineering Research 23: Jain, R. K. and S. Bal Properties o pearl millet. Journal o Agricultural Engineering Research 66: Kabas, O., A. Ozmerzi. and I. Akinci Physical properties o cactus pear (Opuntia icus India L.) grown wild in Turkey. Journal o Food Engineering 73: Karababa, E Physical properties o popcorn kernels. Journal o Food Engineering 72: Keramat Jahromi,., S. Raiee, A. Jaari and A.Tabatabaeear Determination o dimension and area properties o date (Barhi) by image analysis. International Conerence on Agricultural, Food and Biological Engineering and Post Harvest Production Technology, Khon Kaen, January, Thailand. Khoshnam, F., A. Tabatabaeear,. Ghasemi Varnamkhasti and A. Borghei ass modeling o pomegranate (Punica granatum L.) ruit with some physical characteristics. Scientia Horticulturae 114: 1, Lorestani, A.N. and A. Tabatabaeear odeling the mass o kiwi ruit by geometrical attributes. International Agrophysics 20: irasheh, R Designing and making procedure or a machine determining olive image dimensions. aster o Science Thesis, Tehran University. ohsenin, N.N Physical properties o Plant and Animal aterials. 2nd edition (revised). 2 nd Ed.; Gordon & Breach Science Publishers, New York. Owolarae, O.K., T.. Olabigeand and.o. Faborode acro-structural characterisation o palm ruit at dierent processing conditions. Journal o Food Engineering 78: Raiee, S.,. Keramat Jahromi, A. Jaari, A.R. Keyhani and R. irasheh Determination o dimension and mass o date (Deiri). Proceedings o the international conerence on Innovations in Food and Bioprocess Technologies December, Thailand. Suthar, S. H. and S. K. Das Some physical properties o karingda seeds. Journal o Agricultural Engineering Research 65: Tabatabaeear, A Size and shape o potato tubers. International Agrophysics 16(4): Tabatabaeear, A. and A. Rajabipour odeling the mass o apples by its geometrical attributies. Scientia Horticulturae 105: Tabatabaeear, A., A. Veagh-Nematolahee and A. Rajabipour odeling o orange mass based on dimensions. Journal o Agricultural Science and Technology 2: Topuz, A.,. Topakci,. Canakci, I. Akinci and F. Ozdemir Physical and nutritional properties o our orange varieties. Journal o Food Engineering 66: Vursavus, K., H. Kelebek and S. Selli A study on some chemical and physicomechanic properties o three sweet cherry varieties (Prunus avium L.) in Turkey. Journal o Food Engineering 74: