Some Selected Engineering Properties of Seven Genotypes in Quinoa Seeds

Volume06-2018
Advances in Agricultural Science 06 (2018), 02: 36-49

Some Selected Engineering Properties of Seven Genotypes in Quinoa Seeds

Ebubekir Altuntaş 1*, Ismail Naneli 2 , Mehmet Ali Sakin 3

Professor, Department of Biosystem Engineering, Faculty of Agriculture, University of Gaziosmanpasa, 60240, Tasliciftlik, Tokat –Turkey.
Researcher, Department of Field Crops, Faculty of Agriculture, University of Gaziosmanpasa, 60240, Tasliciftlik, Tokat –Turkey.

  Professor, Department of Field Crops, Faculty of Agriculture, University of Gaziosmanpasa, 60240, Tasliciftlik, Tokat –Turkey.

 

ABSTRACT

Some selected engineering properties (geometrical, volumetrical, colour and mechanical) properties of seven genotypes in quinoa seeds were determined and compared in this study. Che. quinoa (red) genotype had the lowest geometric mean diameter and surface area, whereas Che. quinoa (black) genotype had the highest values among 7 quinoa genotypes, for these properties. The bulk density, true density, and porosity of quinoa genotypes were determined between 713.6 and 824.4 kg/m3, 766.9 and 911.4 kg/m3, 6.95 and 15.03% respectively. Che. quinoa (Q11) genotype had the lowest bulk and true densities, whereas Che. quinoa (Ames) genotype had the highest bulk and true density values among quinoa genotypes. The sphericity and seed volume values of Che. quinoa (black) genotype observed in quinoa genotypes were lower than the other quinoa genotypes. The lowest hue angle and chroma colour characteristics values were found as 33.61 and 8.41 in Che. quinoa (black) genotype among quinoa genotypes, respectively. The static friction coefficient and the angle of repose in quinoa genotypes were determined between 0.477 and 0.955, 14.09 and 23.57° respectively.  The lowest rupture force and hardness were found in Che. quinoa (black) genotype, whereas, the highest rupture force and rupture energy were found in Che. quinoa (PI) genotype among quinoa genotypes. The study provides an opportunity that some engineering properties (including physical and mechanical properties in the quinoa seeds of seven genotypes may be useful in designing of the related equipment for postharvest handling and processing operations (harvesting, separating, processing, packing, and transportation).

Keywords: Che. quinoa genotypes, Sphericity, Bulk density, Static friction, Rupture force


How to Cite: Altuntas, E., Naneli, I., & Sakin, M. A. (2018). Some Selected Engineering Properties of Seven Genotypes in Quinoa Seeds. Advances in Agricultural Science, 6(2), 36-49. 

1. Introduction

Quinoa is generally grown in the Andes. Quinoa is ingredient in the preparation of highly nutritious food and functional food supplement (Moncada et al., 2013). In recent years, quinoa has gained increasing interest as a food stuff and functional food due to its high nutritional value, and it is a rich source of vitamin E, dietary fiber, fat content (ranging from 2% to 10%), minerals and carbohydrates, and also it has higher protein content (ranging from 12 to 23%)  than the other cereals. Quinoa is considered as a cell protector and it is important as antioxidants source, phenolic content, polyphenols and also one of the best protein concentrate sources. Therefore, it could be used for medicinal purposes, an ingredient in food such as bread, pasta, baby food and also common diets (Ruales and Nair, 1992; Bhargava et al., 2006; Hirose et al., 2010; Valencia et al., 2010; Vega-Gálvez et al., 2010; Vidueiros et al., 2015).

The quinoa seeds are defined as exerting health promoting effects and lowering the risk of different diseases (Repo-Carrasco et al., 2003; Vega-Gálvez et al., 2010). Quinoa seeds contain the anti-nutritious component saponin in a certain concentration, despite the high nutritional value. Saponins need to be removed before consumption, and saponins are sometimes mentioned to be useful for industrial purposes as molluscicide (Ward, 2000; Joshi et al., 2008).

 In the last few years, quinoa production is grown in the different geographic areas of the World, such as Africa Australia, Asia, Europe and North America, due to its enormous tolerability to adapt to different environmental conditions (FAO, 2011). Due to increasing interest to quinoa in the last decades, quinoa has been selected by FAO as one of the crops destined to offer food security in the 21st century. Quinoa plants show tolerance to drought, salinity, frost, and also they have the ability to grow on unproductive soils (Jacobsen et al., 2003).

To life support in outer space systems, NASA allowed the quinoa plant to be included in the list of candidate crops because of the well recognized nutritive value. Quinoa does not include gluten and it isolates a series of high quality protein with various food purposes. It is potential oil seed crop because it has the high amount and quality fatty acids (Schlick and Bubenheim, 1996; Ng et al., 2007; Abugoch et al., 2008; USDA, 2008). In the last years, quinoa has been introduced into the Europe, United States, Canada and Turkey, and also quinoa is a good candidate crop for agricultural diversification of Turkey (Jacobsen, 1996).

The information on engineering properties of quinoa seeds is important to facilitate and improve for the design of equipment for handling, harvesting, processing, storage, transportation, packing and separation of seeds. The design of the equipment for grading, separation and cleaning, the knowledge of the size distribution of quinoa seeds is important (Selvi et al., 2006). Shape and size dimensions of quinoa seeds are essential in sorting, sizing and separation process. The conveying characteristics of solid materials by air or water was affected by the physical properties of quinoa seeds. The bulk and true densities of quinoa seeds are necessary to design the equipment for storing and bin and drying processing. The porosity of the quinoa seeds affects the airflow resistance through bulk seeds, and also the porosity of quinoa seeds is important for packaging and storing structures. İn addition, to determine of the storage structure and packaging systems for quinoa seed materials and the angle of repose is important and should be known. The static friction coefficient of quinoa seeds are important for the design of seed bins, conveying systems, transport and other storage structures whose operations are influenced by the flow, compressibility and mechanical behaviour of quinoa seed materials. The systems designs for quinoa seeds lead to inadequate applications if the systems are designed without taking into consideration these physical properties (Dursun and Dursun, 2005).

Several researchers investigated the physical properties of the different medicinal and aromatic plant seeds such as fenugreek (Altuntas et al., 2005); flaxseed (Krishna et al., 2013); chia (Salvia hispanica) seed (Ixtaina et al., 2008; Guiotto et al., 2011; Segura-Campos et al., 2014), sesame (Tunde-Akintunde and Akintunde, 2004); cumin (Singh and Goswami, 1996); linseed (Selvi et al., 2006); hemp seed (Sacilik et al., 2003); sainfoin, grasspea and bitter vetch (Altuntas and Karadag, 2006); coriander (Coskuner and Karababa, 2007) respectively. However, no published literature was found and compared on the detailed engineering (geometrical, volumetrical, colour, mechanical) properties of the different quinoa genotypes seeds (Che. quinoa (black), Che. quinoa (white), Che. quinoa (red), Che. quinoa (Q52), Che. quinoa (Q11), Che. quinoa (Ames) and Che. quinoa (PI)). Therefore, some engineering (geometrical, volumetrical, colour, frictional and mechanical) properties in quinoa genotypes were investigated in this study.

2. Materials and Methods

This research was carried out on selected engineering properties in the quinoa seeds of seven genotypes (Che. quinoa (black), Che. quinoa (white), Che. quinoa (red), Che. quinoa (Q52), Che. quinoa (Q11), Che. quinoa (Ames) and Che. quinoa (PI). İn the present study, seed materials of quinoa genotypes used and supplied institutions showed in Table 1. Quinoa seeds were transferred to the laboratory in polyethylene bags to reduce water loss during transport. The seeds were manually cleaned from all damaged foreign materials, immature and broken seeds.

 

Table 1. Used quinoa genotypes and supplied institutions

Quinoa genotypes

Supplied Institution

Origin
Che. quinoa (white) Field Crops Research Institute -Seed Gene Bank (Turkey) Peru
Che. quinoa (black) Demak Food Industry Colombia
Che. quinoa (red) Demak Food Industry Colombia
Q52 Detay Company Chile
Q11(*) Botanic Gardens Conservation International (India) Ethiopia
Che. quinoa Wild Ames 22474

Che. quinoa Wild PI512430

U.S. Department of Agriculture (USDA)

U.S. Department of Agriculture (USDA)

Peru

Chile

(*): Q11 does not saponin.

 

To determine the sizes of the different quinoa genotype seeds, one hundred quinoa seeds were randomly selected. The length, width and thickness of the different quinoa genotype seeds were measured using a dial-micrometer (0.01 mm accuracy), and also the quinoa genotype seed masses (unit seed mass and the thousand seed mass) were measured by using a digital electronic balance (0.01 g.resolution). The geometric mean diameter (Dg), sphericity (Φ), volume, fruit and bulk densities of  quinoa seeds were determined methods presented by Mohsenin (1970); Altuntas and Ozkan (2008). The initial moisture content of the different quinoa genotype seeds was determined by using a standard method (Brusewitz, 1975). The geometric mean diameter (Dg), surface area (S), seed volume (V), sphericity (Φ), and porosity (e) of the different quinoa genotype seeds were calculated by using the following relationships (Mohsenin, 1970; Özarslan, 2002; Olajide and Ade-Omowaye, 1999; Sacilik et al., 2003; Tunde-Akintunde and Akintunde, 2004):

 

where W is the width, L is the length, and T is the thickness in mm, Dg is the geometric mean diameter in mm, S is the surface area in mm2, V is seed volume (mm3), ρt and ρb the true and bulk densities, e is porosity in %.

The colour values of the different quinoa genotype seeds in terms of L* [(the lightness [(0-100)], a* [(green (-∞) – red (∞)], b* [(blue (-∞) – yellow (∞)] were determined by using the Minolta colourimeter (CR-3000 Model). The colours were measured from the different quinoa genotype seed sample bulk surfaces at the three replications (Jha et al., 2005). The chroma (C*) is a measure of chromaticity, which defines the purity or saturation of the colour (McGuire, 1992). C* and h were calculated to the method of Bernalte et al. by Equation 1 and Equation 2 (2003):

The angle of repose in the seven quinoa genotypes seeds was determined by using a bottomless and topless cylinder with 500 mm height and 300 mm diameter. The cylinder was filled with quinoa seeds and was raised slowly until it formed the cone on a circular plate. The angle of repose of the seven quinoa genotypes seeds were calculated from the measurement of the height of the cone and the diameter of cone (Kaleemullah and Gunasekar, 2002). The static coefficient of friction in quinoa seed genotypes are defined as tangent value of the angle of slope between vertical, horizontal planes and sliding surface (Celik et al., 2007). The experiment was conducted using friction surfaces with Rubber, Plywood, Chipboard, Laminate, Silicone, MDF, PVC, Galvanized Metal and glass respectively.

The mechanical behaviour in the different quinoa genotype seeds were expressed in terms of rupture force, deformation, rupture energy, hardness and toughness required for initial rupture. A biological material test device was used to determine the mechanical properties in quinoa seed genotypes. This device has the moving platform, the driving unit and a load cell, PC card and software systems. For the compression test measurements of seeds in the different quinoa genotypes were used 14,7 mm diameter cylindrical stainless steel plate with biological materials test device (Sundoo, SH–2, 500 N, China). The quinoa seed was placed on the moving platform considering the normally stand up loading position, and pressed with a plate fixed on the load cell until the quinoa seed ruptured. Deformation was measured from fixed moving platform on the device stand. Force-time curves were recorded, Three replication were made for each test, and also fifteen samples were used in each test.

The rupture energy (Er), hardness (Q) and toughness (To) of the different quinoa genotype seeds were calculated by using the following relationships (Mohsenin, 1970; Braga et al., 1999; Olajide and Ade-Omowaye, 1999; Gupta and Das, 2000; Özarslan, 2002; Ozturk et al., 2009; Sacilik et al., 2003; Tunde-Akintunde and Akintunde, 2004; Sirisomboon et al., 2007):

 

 

Where Dr is the deformation in mm, Fr is the rupture force of quinoa seed at rupture point, V is the volume of quinoa seed in mm3, Er is the energy absorbed in mJ, To is toughness is the mJ mm3, Q is the hardness in N mm-1. Experimental results were analyzed as per one-factor analysis of variance using Duncan of SPSS 13.0 software statistical package programme (SPSS, 2000).

3. Results and Discussion

Some selected engineering properties (geometrical, volumetrical, colour and mechanical) properties of seeds in the seven quinoa genotypes (Che. quinoa (black), Che. quinoa (white), Che. quinoa (red), Che. quinoa (Q52), Che. quinoa (Q11), Che. quinoa (Ames) and Che. quinoa (PI) were evaluated.

3.1. Geometrical properties

The seed geometrical properties of the different quinoa genotypes (Che. quinoa (black), Che. quinoa (white), Che. quinoa (red), Che. quinoa (Q52), Che. quinoa (Q11), Che. quinoa (Ames) and Che. quinoa (PI) ) are given in Table 2 respectively. The lower length and width in the quinoa seeds were obtained as 1.65 mm and 2.13 mm from Che. quinoa (black) genotype, whereas the higher length and width in the quinoa seeds were found as 1.72 and 2.19 mm from Che. quinoa (red) genotype among the seven quinoa genotypes respectively (Table 2). The geometric mean diameter (Dg), sphericity and surface area of seeds for seven quinoa genotypes ranged from 1.45 to 1.76 mm, 80.78% to 88.29% and 6.66 to 9.76 mm2 respectively. The higher geometric mean diameter and surface area were found in Che. quinoa (red) genotype of quinoa. The length, width and thickness for all the seven genotypes varied statisticaly significantly (p<0.01) (Table 2).

Table 2. The geometrical properties of quinoa genotypes.

Quinoa genotypes Length

 

L (mm)

Width

 

W (mm)

Thickness

 

T (mm)

Geometric mean diameter

Dg (mm)

Sphericity

 

F  (%)

Surface area        

S (mm2)

Che. quinoa (black) 1.649e 1.720d 1.094e 1.453f 88.289a 6.66f
(12.69 % d.b) (0.011) (0.012) (0.020) (0.010) (0.557) (0.096)
Che. quinoa (white) 2.085ab 1.911c 1.197a 1.680b 80.781e 8.876b
(11.67% d.b) (0.012) (0.019) (0.004) (0.007) (0.467) (0.071)
Che. quinoa (red) 2.125a 2.194a 1.176b 1.761a 82.930e 9.757a
(12.79 % d.b) (0.007) (0.017) (0.008) (0.007) (0.351) (0.080)
Che. quinoa (Q52) 1.780d 1.725d 1.149cd 1.521e 85.482b 7.269e
(13.68 % d.b) (0.006) (0.011) (0.009) (0.005) (0.299) (0.050)
Che. quinoa (Q11) 2.020c 1.935bc 1.156c 1.652d 81.816cd 8.572cd
(15.07 % d.b) (0.004) (0.006) (0.004) (0.003) (0.168) (0.032)
Che. quinoa (Ames) 2.016c 1.982b 1.182b 1.677bc 83.240c 8.837d
(15.06 % d.b) (0.007) (0.009) (0.004) (0.004)         (0.215) (0.040)
Che. quinoa (PI) 2.046bc 1.978b 1.137d    1.656cd            81.308de 8.625bc
(15.50 % d.b) (0.004) (0.004) (0.002) (0.006)        (0.119) (0.054)
F value 158.26** 105.11** 50.79** 191.91**           34.45** 200.67**

†: Moisture content (% d.b. dry basis)

Values in the parenthesis are standard error of the mean (SEM);

 ** p<0.01 , all values are mean of five replicates

 

Zewdu (2011) determined that the width, length, and thickness of ajwain seeds ranged from 1.15 to 1.22 mm, 1.91 to 2.20 mm, and 0.87 to 0.93 mm under different moisture content (from 4.39 to 21.6% w.b.) respectively. Abalone et al. (2004), the average length, width, thickness and sphericity of Amaranth seeds found as 1.42, 1.29 and 0.87 mm respectively, which were lower than the quinoa seed genotypes. Zewdu (2011) determined that the sphericity and geometric mean diameter of ajwain seeds ranged from 61 to 65% and 1.24 to 1.35 mm (at the moisture content from 4.39 to 21.6% (w.b.), which were lower than the quinoa genotypes. Selvi et.al. (2006) determined that the geometric mean diameter and the moisture content ranged from 2.24 to 2.43 mm and 8.25 to 22.25% (d.b.) respectively, which were higher than all studied quinoa genotypes. Ixtaina et al. (2008) determined that geometric mean diameter of dark and white chia seeds ranged from 1.31 to 1.36 mm, which were lower than the seven quinoa seed genotypes. Moisture content of quinoa genotypes ranged from 11.67% to (Che. Quinoa white) 15.50% (Chenepodium quinoa PI), 12.69% (Che. Quinoa black), 12.79% (Che. Quinoa red), 13.68% (Q52), 15.06% (Che. Quinoa Ames) 15.07% (Q11) (dry basis) respectively (Table 2).

3.2. Volumetrical Properties

The volumetrical properties of seven genotypes in quinoa seeds are presented in Table 3. The unit seed mass, thousand seed mass and seed volume values were range from 0.0035 to 0.0011 g, 1.22 to 2.86 g and 1.63 to 2.87 mm3 respectively. The least unit seed mass and 1000-seed mass values were consisted by Che. quinoa (Q11), whereas the highest seed mass and 1000-seed mass values were recorded for Che. quinoa (Q52) genotype among the quinoa genotypes. In this study, the 1000-seed mass was found lower for quinoa seeds than determined by Selvi et al. (2006), which was 6.0 g at 8.25% (d.b.) moisture content. Despite the thousand seed mass, unit seed mass, and seed volume of tef seed (Zewdu and Solomon, 2006) lower than seven quinoa genotypes, but millet seed (Baryeh, 2001) and caper seed (Dursun and Dursun, 2005) higher than seven quinoa genotypes.

Table 3. The volumetrical properties of the different quinoa genotypes.

Quinoa genotypes Seed mass.

M (g)

Thousand  seed mass

M1000 (g)

Volume

V (mm3)

Bulk density.

ρf (kg m-3)

True density.

ρf (kg m-3)

Porosity

 

P (%)

Che. quinoa (black) 0.00144e 1.391d 1.630e 717.7e 843.3c 14.89a
  (3.24×10-6) (0.0044) (0.037) (1.774) (1.304) (0.156)
Che. quinoa (white) 0.00149d 1.453c 2.493b 733.7d 826.0c 11.15b
  (4.69×10-6) (0.0059) (0.029) (0.624) (3.796) (0.480)
Che. quinoa (red) 0.00148de 1.458c 2.874a 772.3c 825.0c 6.38c
  (4.94×10-6) (0.0083) (0.036) (0.649) (1.962) (0.284)
Che. quinoa (Q52) 0.00350a 2.864b 1.847d 819.4ab 971.6a 15.66a
  (5.90×10-6) (0.0105) (0.019) (0.463) (2.772) (0.262)
Che. quinoa (Q11) 0.00109f 1.218e 2.362c 706.5f 753.2d 6.19c
  (1.20×10-5) (0.0063) (0.013) (1.110) (3.482) (0.330)
Che. quinoa (Ames) 0.00205b 2.886a 2.473b 826.4a 911.4b 9.31b
  (1.91×10-5) (0.0046) (0.017) (2.172) (6.211) (0.434)
Che. quinoa (PI) 0.00173c 2.702c 2.386c 811.0b 903.7b 10.18b
  (9.26×10-6) (0.0104) (0.020) (3.692) (11.371) (0.718)
F value 2908.53** 9392.98** 208.74** 252.25** 58.09** 26.58**

Values in the parenthesis are standard error of the mean (SEM)

**p<0.01 , all values are mean of five replicates

 

The porosity of the quinoa seeds ranged from 6.95 to 15.03%. The porosity among the different quinoa genotypes were found higher Che. quinoa (Q52) and lower Che. quinoa (Q11) than the other quinoa genotypes. The effect of genotypes on porosity of quinoa seeds was significantly found  (p<0.01) as values. Similar results for porosity also determined by Vilche et al. (2003), whereas porosity of quinoa genotypes was found lower than cumin seed (Singh and Goswami, 1996) and tef seed (Zewdu, 2007), respectively.

The effects of genotypes on volumetrical properties were significant for quinoa seeds (Table 3). The true density of quinoa genotypes was ranged from 766.9 to 911.4 kg m-3 for the moisture range of 11.67% to 15.50% d.b. The highest true density was observed for Che. quinoa (Ames) (911.4 kg m-3) at the moisture content of 15.07% d.b. The true density values for genotypes (Che. quinoa (black), Che. quinoa (white), Che. quinoa (red), Che. quinoa (Q52), Che. quinoa (Q11), Che. quinoa (Ames) and Che. quinoa (PI) were evaluated. The volumetrical properties (true density, bulk density, seed mass, volume, porosity, thousand seed mass) were statistically found significant (p<0.01) (Table 3). Bulk density of quinoa seeds was found highest for Che. quinoa (Ames) (824.4 kg m-3) and also lowest value (713.6 kg m-3) was observed for Che. quinoa (Q11). The true and bulk densities of quinoa seeds can be used to cleaning process, design of separation, bins and dryers processing and storing (Dursun and Dursun, 2005; Unal et al., 2009).

Singh and Goswami (1996) determined that the bulk density and true density for cumin seed varied from 410 to 502 kg m-3, 1047 to 1134 kg m-3, whereas, the porosity of cumin seed ranged from 54 to 64%. Dursun and Dursun (2005)  determined that the true density, porosity and bulk density of caper seed were found as 806 to 678 kg m-3, 45.7 to 41.1%, and 438 to 399 kg m-3 respectively. Önen et al. (2014) reported that the bulk density of knotweed (Polygonum cognatum Meissn.) seeds ranged from 696.11 to 707.73 kg m-3, and also Selvi et al. (2006) found betwen 545.0 and 690.5 kg m-3 for linseed respectively. The range of true density in the studied quinoa genotypes seeds was lower than the determined values of Singh and Goswami (1996) and Dursun and Dursun (2005), whereas bulk density was higher than the determined literatures.

3.3. Colour Characteristics

Colour characteristics (lightness, redness, and yellowness) of the different quinoa genotypes are presented in Table 4. The maximum value for lightness (L*) was found to be 68.82 for Che. quinoa (white) genotype, whereas minimum L* value was recorded as 21.77 for Che. quinoa (black) genotype. Significant differences (p < 0.01) were found among salvia species for colour characterictics such as lightness, redness, yellowness, chroma and hue angle. The lightness was found statistically similar between Che. quinoa (Ames) and Che. quinoa (PI) of quinoa genotypes. The hue angle ranged from 33.65 to 72.15° with highest value for Che. quinoa (Q11) and lowest for Che. quinoa (black) genotypes of quinoa seed. The hue angle values of Che. quinoa (Q52), Che. quinoa (Q11), Che. quinoa (Ames) and Che. quinoa (PI) genotypes of quinoa seed were statistically similar.

 

 

Table 4. The colour characteristics properties of quinoa genotypes.

Quinoa genotypes L* a* b* Chroma Hue angle Brown index
Che. quinoa (black) 21.77e 6.91b 4.73d 8.41c 33.65d 46.53b
  (0.707) (0.385) (0.451) (0.364) (1.177) (1.767)
Che. quinoa (white) 68.82a 5.40d 18.82a 19.58a 73.99a 37.22c
  (0.491) (0.088) (0.175) (0.170) (0.095) (0.600)
Che. quinoa (red) 25.07d 14.73a 11.04c 18.41b 36.84b 98.06a
  (0.369) (0.162) (0.143) (0.107) (0.325) (0.793)
Che. quinoa (Q52) 54.55c 5.82cd 17.47b 18.41b 71.58ab 45.79b
  (0.353) (0.079) (0.206) (0.122) (0.154) (0.159)
Che. quinoa (Q11) 57.46b 6.07c 18.85a 19.80a 72.15ab 46.87b
     (0.459) (0.024) (0.153) (0.113) (0.130) (0.255)
Che. quinoa (Ames) 58.36b 6.21bc 19.07a 20.06a 71.96ab 46.73b
  (0.242) (0.020) (0.153) (0.035) (0.045) (0.099)
Che. quinoa (PI) 58.10b 6.39bc 18.55a 19.62a 70.99b 45.93b
  (0.332) (0.072) (0.135) (0.098) (0.177) (0.300)
F value 1210.34** 324.76** 383.86** 192.17** 482.34** 225.76**

Values in the parenthesis are standard error of the mean (SEM),

**p<0.01 , all values are mean of five replicates

 

 

The chroma values were varied in the range of 8.41 to 19.80 as lowest for Che. quinoa (black) and highest for Che. quinoa (Q11) genotypes of quinoa seed respectively.  Brown index values were varied in the range of 37.22 to 98.06 as lowest for Che. quinoa (white) and highest for Che. quinoa (red) genotypes of quinoa seed respectively. Brown index values of seven genotypes in quinoa seeds were statistically different (p<0.01). L*, a*, b*, hue angle and chroma values were found for Che. quinoa (black) genotype lower than the other quinoa genotypes.

3.4. Frictional Properties

The frictional properties of quinoa seed genotypes are given in Table 5. The coefficient of static friction for the quinoa seed genotypes was determined on the rubber, plywood, silicone, chipboard, MDF, PVC, galvanized metal and glass frictional surfaces (Table 5). The static coefficient of friction was lowest for all quinoa genotypes on laminate among the studied friction surfaces.

The static coefficient of friction ranged from 0.389 to 0.435, 0.373 to 0.493, 0.451 to 0.490, 0.422 to 0.511,  0.353 to 0.443, 0.350 to 0.418, 0.350 to 0.405 and 0.342 to 0.405; for rubber, plywood, laminate, silicone, chipboard, MDF, PVC, galvanized metal and glass, among the seven quinoa genotypes seeds respectively (Table 5). There were significant statistically differences in the coefficients of static friction among the quinoa genotypes on the seven different surfaces (p<0.01) (Table 5).

Che. Quinoa (black) showed lowest static coefficient of friction as 0.324 value for galvanized metal among nine friction surfaces. This may be due to more polished surface than the other test surfaces. Static friction coefficient of quinoa genotypes largely influenced by the different friction surfaces. Singh and Goswami, (1996) reported that the static coefficient of friction of cumin seed changed on four metal surfaces, namely, mild steel from 0.54 to 0.70, galvanized iron from 0.48 to 0.65, stainless steel from 0.37 to 0.62 and aluminium from 0.43 to 0.63  in moisture content from 7 to 22% d.b., respectively. Dursun and Dursun (2005) determined that the static coefficient of friction for caper seed increased in increasing moisture content from 0.55 to 0.70 for rubber, 0.52 to 0.66 for plywood, 0.40 to 0.47 for galvanized metal sheet and 0.36 to 0.46 for aluminium sheet. Ixtaina et al. (2008) determined that the static coefficient of friction for chia seed was 0.28 on galvanized sheet and 0.31 on mild steel sheet, which were lower than the seven quinoa seed genotypes.

The highest and the lowest static coefficient of friction were found on the chipboard surface and galvanized metal for Che. Quinoa (Ames) and Che. Quinoa (red) quinoa genotypes in this study respectively. Static coefficient of friction for quinoa genotype seeds on galvanized metal friction surface was lower than millet (Baryeh, 2001),  quinoa seed (Vilche et al., 2003), ajwan (Zewdu, 2011), cumin (Singh and Goswami, 1996), African star apple (Oyelade et al., 2005), flaxseed (Singh et al., 2013), and fenugreek (Altuntas et al., 2005), whereas it was higher than sesame (Tunde-Akintunde and Akintunde, 2004), nigella seed at 5.08 moisture content (% d.b.) and hempseed at 8.62 moisture content respectively.

 

Table 5. The frictional properties of Quinoa genotypes.

Quinoa genotypes Friction surfaces

 

Rubber Plywood Laminate Silicone Chipboard MDF (x) PVC (&) Glass Galvanized metal
Che. quinoa 0.389c 0.385d 0.324c 0.487a 0.422c 0.371c 0.350b 0.350c 0.346c
(black) (0.0011) (0.0018) (0.0033) (0.0032) (0.0011) (0.0016) (0.0028) (0.0023) (0.0013)
Che. quinoa 0.406b 0.447c 0.343b 0.451b 0.488b 0.429b 0.418d 0.357bc 0.360b
(white) (0.0033) (0.0026) (0.0013) (0.0027) (0.0036) (0.0018) (0.0030) (0.0048) (0.0045)
Che. quinoa 0.367d 0.375e 0.327c 0.458b 0.397d 0.352d 0.350b 0.368b 0.340c
(red) (0.0005) (0.0006) (0.0016) (0.0019) (0.0019) (0.0011) (0.0015) (0.0021) (0.0009)
Che. quinoa 0.433a 0.480b 0.352ab 0.490a 0.480b 0.440a 0.405ab 0.405a 0.405a
(Q52) (0.0023) (0.0021) (0.0014) (0.0019) (0.0023) (0.0017) (0.0043) (0.0009) (0.0019)
Che. quinoa 0.432a 0.493a 0.354a 0.488a 0.508a 0.436ab 0.399b 0.402a 0.398a
(Q11) (0.0009) (0.0028) (0.0010) (0.0025) (0.0009) (0.0017) (0.0012) (0.0026) (0.0009)
Che. quinoa 0.428a 0.478b 0.348ab 0.485a 0.511a 0.443a 0.408ab 0.398a 0.398a
(Ames) (0.0010) (0.0014) (0.0012) (0.0016) (0.0012) (0.0019) (0.0034) (0.0004) (0.0013)
Che. quinoa 0.435a 0.478b 0.352ab 0.486a 0.489b 0.435ab 0.406ab 0.397a 0.398a
(PI) (0.0019) (0.0011) (0.0018) (0.0018) (0.0040) (0.0010) (0.0034) (0.0006) (0.0004)
F value 71.23** 208.43** 14.71** 12.65** 70.30** 166.36** 30.92** 29.92** 57.93**

(x): MDF: Medium Density Fiberboard,  (&): PVC: Polyvinyl Chloride, Values in the parenthesis are standard error of the mean (SEM),  **p<0.01 , all values are mean of five replicates

 

3.5.Angle of repose

The angle of repose in the quinoa genotypes is presented in Figure 1. The angle of repose in the quinoa genotypes ranged from 6.32° (Che. quinoa (red) to 11.09° (Che. quinoa (Q11). The effect of quinoa seed genotypes on angle of repose was found statically significant (p<0.01) (Fig 1).

 

Figure 1. The angle of repose of quinoa genotypes.

 

The angle of repose in Che. quinoa (white) and  Che. quinoa (Ames) genotypes found statistically similar. Also Che. quinoa (black) and Che. quinoa (PI) genotypes were also found to be statistically similar as the angle of repose. Among seven quinoa genotypes, the longest length was found in Che. quinoa (red) seed at the same time, although it has been seen that Che. quinoa (red) has the smallest angle of repose.  The angle of repose values for all the quinoa seed genotypes are lower than millet (Baryeh, 2001), sesame (Tunde-Akintunde and Akintunde, 2004), cumin (Singh and Goswami, 1996), Knotweed (Polygonum cognatum Meissn.) seeds (Önen et al., 2014), flaxseed (Singh et al., 2013), nigella seed (Singh et al., 2005), and hemp seed (Sacilik et al., 2003).  The approximation results for angle of repose in quinoa genotypes reported for fenugreek seed (Trigonella foenum graceum) in this study (Altuntas et al., 2005).

 3.6. Mechanical properties

The mechanical properties of quinoa seed genotypes are given in Table 6. The mechanical properties for the quinoa seed genotypes was determined as rupture force, deformation, hardness, rupture energy and toughness respectively. The rupture force was lower for all quinoa genotypes at Che. Quinoa (black) and Che. Quinoa (White) as 21.17 N and 21.79 N respectively. The rupture force values ranged from 21.17 N to 40.61 N among the quinoa seed genotypes. Rupture force in quinoa genotypes largely influenced by the different quinoa genotypes. There were significant statistically differences in the rupture force, deformation, hardness, rupture energy and toughness, among the quinoa genotypes (p<0.01) (Table 6).

Table 6. The mechanical characteristics of Quinoa genotypes.

Quinoa genotypes Rupture force (N) Deformation

(mm)

Hardness

(N/mm)

Energy

(N mm)

Toughness

(N/mm2)

Che. quinoa (black) 21.17c 0.71a 30.97c 7.60cd 4.67bc
  (0.91)c (0.04) (1.46) (0.64) (0.39)
Che. quinoa (white) 21.79 0.40c 60.39b 4.27d 1.71d
  (0.46) (0.02) (2.22) (0.32) (0.13)
Che. quinoa (red) 30.76b 0.47bc 72.77a 7.21cd 2.51cd
  (0.20) (0.03) (5.31) (0.37) (0.13)
Che. quinoa (Q52) 37.64ab 0.75a 53.94b 14.56b 7.88a
  (1.96) (0.02) (3.05) (0.96) (0.52)
Che. quinoa (Q11) 32.58ab 0.60ab 59.62ab 10.09ab 4.27bc
  (2.08) (0.03) (2.37) (1.03) (0.44)
Che. quinoa (Ames) 35.76ab 0.67a 54.33ab 11.97ab 4.84bc
  (0.57) (0.02) (0.98) (0.43) (0.17)
Che. quinoa (PI) 40.61a 0.72a 60.08ab 14.73ab 6.17a
  (0.67) (0.04) (4.24) (0.85) (0.36)
F value 13.269** 7.309** 5.426** 10.283** 12.653**

Values in the parenthesis are standard error of the mean (SEM),

**p<0.01 , all values are mean of five replicates

 

The rupture energy ranged from 4.27 N mm to 14.73 N mm among the quinoa seed genotypes and rupture energy was lower and higher than the other quinoa seed genotypes at Che. quinoa (white) and  Che. quinoa (PI), respectively. Deformation and hardness of the quinoa seeds varied from 0.40 to 0.75 mm and from 30.97 to 72.77 among genotypes, respectively. The deformation of Che. quinoa (black) and Che. quinoa (PI) genotypes showed statistically similar, whereas the hardness of Che. quinoa (Q11) and Che. quinoa (PI) genotypes showed statistically similar. The deformation and hardness among the quinoa seed genotypes were lower at Che. quinoa (white) with 0.40 mm and Che. quinoa (black) with 30.97 N mm-1 than the other quinoa seed genotypes, respectively (Table 6). Toughness values among the quinoa seed genotypes were lower and higher at Che. quinoa (white) with 1.71 N mm-2 and Che. quinoa (Q52) with 7.88 N mm-2 than the other quinoa seed genotypes, respectively. The toughness of Che. quinoa (Q11) and Che. quinoa (Ames) genotypes showed statistically similar, and also toughness ranged from 1.71 to 7.88 N mm-2 among the quinoa seed genotypes.

Saiedirad et al. (2008) determined that the rupture force and absorbed energy for cumin seed changed from 15.7 to 11.96 N; 1.8 to 8.6  mJ (vertical) and 58.2 to 28.8 N; 7.6 to 14.6 mJ (horizontal) with increase in moisture content from 5.7% to 15% d.b., respectively. Fadeyibi and Osunde (2012) determined that the mechanical behaviour of rubber seed in terms of optimum peak values of compressive force, stress, energy and deformation were as 164.35 N, 2.09 N mm-2, 0.27 Nm, 2.74 mm at 14.8 % (w.b.) moisture content respectively.

Taheri-Garavand et al. (2012) carried out an investigation on the effects of the moisture content on some mechanical properties of hemp seeds and he reported that the increase in the moisture content from 5.39 to 27.12% d.b., the rupture force and and energy required to initiate hemp seed rupture decreased from 36.65 to 18.67 N and 10.25 to 5.41 mJ respectively. Range of rupture force and the energy absorbed required to initiate quinoa seed genotypes was higher than the reported values at compression along vertical orientiation of cumin seed of Altuntas and Yildiz (2007) reported that, rupture force values for faba bean grain ranged: 314.17-185.10 N; 242.2-205.56 N; and 551.43-548.75 N for X-, Y-, and Z-axes as the moisture content increased from 9.89 to 25.08%, which higher than the seven quinoa seed genotypes.  Saiederad et al. (2008) and the deformation of quinoa seed values was higher than the reported values of rubber seed, whereas, rupture force, rupture energy were similar by reported values of Taheri-Garavand et al. (2012), respectively.

4. Conclusion

The following conclusions are drawn from the investigation on some selected engineering (geometrical, volumetrical, colour and frictional) properties of seven quinoa genotypes seeds.

-Among these seven quinoa genotypes, Che. quinoa (red) genotype had the highest  geometric mean diameter and surface area, whereas Che. quinoa (black) had the least values. Bulk density of quinoa genotypes was found highest for Che. quinoa (Ames) and lowest was observed for Che. quinoa (black), whereas the highest true density was observed for Che. quinoa (Q52) among the seven quinoa genotypes seeds.

-The hue angle ranged from 33.65  to 73.99° with highest value for Che. quinoa (white) and lowest for Che. quinoa (black) genotypes among the seven quinoa genotypes, whereas Chroma changed from 8.41 to 20.06 with lowest value for Che. quinoa (black) and the highest for Che. quinoa (Ames) genotypes among the seven quinoa genotypes,  

-Che. quinoa (red) showed the lowest static coefficient of friction for rubber, plywood, chipboard, MDF, and galvanized metal among nine surfaces respectively. The laminate surface offered the minimum static coefficient of friction among test surfaces. Static friction coefficient of quinoa genotypes statistically influenced by friction surfaces.

-The lowest and highest angle of repose in the studied qunioa genotypes were found in Che. quinoa (red)   with 6.32° and Che. quinoa (Q11) with 11.09°, respectively.

-The rupture force was lower at Che. quinoa (black) and Che. quinoa (White) as 21.17 N and 21.79 N, for all quinoa genotypes respectively. The deformation and hardness among the quinoa seed genotypes were lower at Che. quinoa (white) and Che. quinoa (black) than the other quinoa seed genotypes respectively. Toughness values among the quinoa seed genotypes were lower and higher at Che. quinoa (white) and Che. quinoa (Q52) among the quinoa seed genotypes, respectively.

The some selected engineering (geometrical, volumetrical, colour and frictional) properties of seven quinoa seed genotypes will serve to design the equipment used in postharvest treatment and processing of quinoa genotypes seeds.

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