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Mechanical damages such as bruising, collision and impact during food processing stages diminish quality and quantity of productions as well as efficiency of operations. Studying mechanical characteristics of food materials will help to enhance current industrial practices. Mechanical properties of fruits and vegetables describe how these materials...
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... stress and strain calculated using the formula and cross sectional area (Fig. 7). Value of stress varied between 5.784 to 6.757 MPa in bio-yield point ( Table 1). The details of two points after yield point have been recorded as first effective stress values in plastic region which is essential for completing computer model of tissue. ...
Citations
... N/mm, for loading speeds of 1.25, 10 and 20 mm/min, respectively. The average value of the force on the biological yield strength of the pumpkin peel was 310 N [15]. ...
The review of equipment for processing and technology of processing melons and gourds is given. Primary processing of gourds has not been industrialized in the CIS countries and abroad until recent years. Theoretical prerequisites for the creation of products based on melon are presented, the issues of rational use of melon for the production of long-term storage products are highlighted. The main physical-mechanical and rheological properties of pumpkin, melon and watermelon fruits are given. The proposed options for equipment and technological lines for the processing of watermelon, melon, pumpkin fruits are presented. The technologies for processing the fruits of watermelon and melon are described.
The object of research: Melons and gourds, namely processing technology
Investigated problem: Imperfect technologies for processing melon fruits.
The main scientific results: systematization of data on the problem of processing melon fruits for food in order to choose a rational way to improve processing technologies.
The area of practical use of the research results: The bottom line is the developed technologies
Innovative technological product: technology for processing gourds.
Scope of the technological innovative product: food industry (Food production).
... N/mm, for a feed rate of 1.25, 10 and 20 mm/min, respectively. The average value of the force at the biological yield point of pumpkin rind was 310 N [23]. ...
... Fig. 2.23 Graphs of the dependence of the piercing force of the melon rindon the angle of spike sharpening ( ...
... This conclusion was also reached by Stelte et al. (2011) andMiao et al. (2015). The compression diagrams are very similar to compression testing of biological materials presented by Shirmohammadi et al. (2011), proving that the observed pellets show behaviour typical for biological materials in general. ...
The work deals with evaluation of mechanical properties three types of pellet samples produced from poppy waste. The pellets were submitted to compressive loading. The compressive loading curves of dependencies of force on strain and force on time were realised. Certain mechanical parameters were determined, namely the diameter of the sample, length of the sample, force at 10% of strain, force in the first maximum of the force – strain curve, strain in the first maximum of the force – strain curve, modulus of elasticity, force in the inflex point of the force – time and force – strain curves and strain and stress in the inflex point of the force – time and force – strain curves. The work lists correlations of mechanical parameters of individual pellet types. The pellet type 1 made only of ground poppy head mass has shown the best results, the pellet type 3 consisting of ground poppy heads after harvest and waste from sieving of poppy seeds in mass proportion 1 : 1 has shown the worst results.
... The same result is approximatively valid for apparent modulus of elasticity. Shirmohammadi, M. et al. (2011) realized empirical investigation on mechanical properties of pumpkin peel. The compression test has been conducted on Jap variety of pumpkin. ...
Paper dealt with the determination of mechanical properties of greengage plum fruit of variety Prunus Angeleno. The Angeleno plum is a common late season variety which almost becomes the only choice for consumers in autumn (as the northern hemisphere season ends) and spring (as the southern hemisphere season ends). This is a dark red plum with a pale yellow flesh and small stone. The flesh is dense and crunchy, without much juice, but sweet with well-balanced flavour due to the long growing time. It will not soften , as main-steam plum varieties will, and is a totally different experience to the soft succulent Victoria plum. Angeleno is popular with growers due to ease of storage and transport, and it's late-season slot in their production calendar. Origin of Angeleno is USA, released in 1995. Angeleno is also known a Suplumsix, a Sunworld variety. The compress test was realized by means of test stand Andilog Stentor 1000. The compress load curves of the stress on the strain were evaluated of the lateral and longitudinal directions by two methods. The moduli of elasticity were determined and the stress and the strain in the rupture point and the bioyield point were evaluated. The modulus of elasticity in the lateral loading achieved the value about 1 MPa and the stress in the bioyield point was 0.3 MPa. The strain in the bioyield point was 0.3 mm/mm. The stress in the rupture point was 0.3 MPa and the strain in the rupture point was 0.5 mm/mm. The modulus of elasticity in the longitudinal loading achieved the value about 2 MPa and the stress in the bioyield point was 0.6 MPa. The strain in the bioyield point was 0.3 mm/mm.The stress in the rupture point was 0.5 MPa and the strain in the rupture point was 0.5 mm/mm.
... An Instron Universal Testing machine was used to apply loads and the results of the load deformation were obtained from the computer attached to the machine. The details of tests were similar with the previous work on tough skinned vegetables [15][16][17][18]. Samples were reserved in a fixative solution of Glutaraldehyde 3% for at least 2 hours after the each test. ...
The texture of agricultural crops changes during harvesting, post harvesting and processing stages due to different loading processes. There are different source of loading that deform agricultural crop tissues and these include impact, compression, and tension. Scanning Electron Microscope (SEM) method is a common way of analysing cellular changes of materials before and after these loading operations. This paper examines the structural changes of pumpkin peel and flesh tissues under mechanical loading. Compression and indentation tests were performed on peel and flesh samples. Samples structure were then fixed and dehydrated in order to capture the cellular changes under SEM. The results were compared with the images of normal peel and flesh tissues. The findings suggest that normal flesh tissue had bigger size cells, while the cellular arrangement of peel was smaller. Structural damage was clearly observed in tissue structure after compression and indentation. However, the damages that resulted from the flat end indenter was much more severe than that from the spherical end indenter and compression test. An integrated deformed tissue layer was observed in compressed tissue, while the indentation tests shaped a deformed area under the indenter and left the rest of the tissue unharmed. There was an obvious broken layer of cells on the walls of the hole after the flat end indentations, whereas the spherical indenter created a squashed layer all around the hole. Furthermore, the influence of loading was lower on peel samples in comparison with the flesh samples. The experiments have shown that the rate of damage on tissue under constant rate of loading is highly dependent on the shape of equipment. This fact and observed structural changes after loading underline the significance of deigning postharvesting equipments to reduce the rate of damage on agricultural crop tissues.
... Al. 250N [12]. The rupture force for pumpkin peel was close to the results of study by Shirmohammadi et al which reported rupture force of 310N [18]. However, the results were higher than rupture force calculated for watermelon peel and honey melon unpeeled samples, 175 and 183 respectively [10] which can be due to the tough structure of pumpkin peel and flesh in comparison with watermelon and honey melon. ...
... Applying Finite Element Modelling and simulation of engineering operations is an innovative trend among researchers and designers of industrial technologies. Applying these models is helping researchers to measure and calculate different properties and characteristics under loading which sometimes is very difficult to be calculate with experimental tests [21]. of materials These models are applicable to study rate of energy consumptions, tool wear and material loss in real world operations [18,22]. This applications will help to achieve precise understanding of interrelationship of different variable involve the processes to improve tool design and select optimum conditions [23]. ...
Purpose: The purpose of this study was to calculate mechanical properties of tough skinned vegetables as a part of Finite Element Modelling (FEM) and simulation of tissue damage during mechanical peeling of tough skinned vegetables. Design/methodology: There are some previous studies on mechanical properties of fruits and vegetables however, behaviour of tissue under different processing operations will be different. In this study indentation test was performed on Peel, Flesh and Unpeeled samples of pumpkin as a tough skinned vegetable. Additionally, the test performed in three different loading rates for peel: 1.25, 10, 20 mm/min and 20 mm/min for flesh and unpeeled samples respectively. The spherical end indenter with 8mm diameter used for the experimental tests. Samples prepare from defect free and ripped pumpkin purchased from local shops in Brisbane, Australia. Humidity and temperature were 20-55% and 20-25 0 C respectively. Findings: Consequently, force deformation and stress and strain of samples were calculated and shown in presented figures. Relative contribution (%) of skin to different mechanical properties is computed and compared with data available from literature. According the results, peel samples had the highest value of rupture force (291N) and as well as highest value of firmness (1411Nm -1). Research limitations/implications: the proposed study focused on one type of tough skinned vegetables and one variety of pumpkin however, more tests will give better understandings of behaviours of tissue. Additionally, the behaviours of peel, unpeeled and flesh samples in different speed of loading will provide more details of tissue damages during mechanical loading. Originality/value: Mechanical properties of pumpkin tissue calculated using the results of indentation test, specifically the behaviours of peel, flesh and unpeeled samples were explored which is a new approach in Finite Element Modelling (FEM) of food processes.
... Traditional peeling methods have applied labour intensive manual peeling account the increasing growth of processed agricultural product sector, coupled with technological developments of processing equipment, it becomes clear that manual peeling will not remain an economically viable processing method to provide sufficient quantity to meet the growi Mechanical peeling includes different types of mechanisms that interact directly with skin and remove it commercial mechanical peelers are abrasive devices, drums, rollers, knives and milling cutters. Although m peelers can provide high quality fresh final products and they are environmentally friendly and nontoxic downside of these methods relates to the associated loss [18]. Skin thickness, firmness, toughness, variety, rupture force, cutting force, maximum shearing force, shear strength, tensile strength and rupture stress are some of the fruits properties that would have direct effect on the peeling process. ...
... There are some published studies which calculated effective physical and mechanical properties of fruits and vegetables [13,16,[18][19][20][21][22][23][24][25][26][27][28][29][30][31][32]during post harvesting processes including handling, grading, sorting, transporting, packaging. Still, there is the need of more investigation to and connect available properties to model actual reactions of fruits and vegetables tissue which will help to mechanical tissue damage and enhance total effectiveness food industrial operations. ...
... The results of FE modelling of mechanical peeling of fruits and vegetables will enhance industrial peeling stage and can be helpful to rate of material loss [18]. Another significant models is possibility of predicting and estimating deformation and waste during and after mechanical peeling, increasing and improving tool life and reducing wear tool. ...
Peeling is an essential phase of post harvesting and processing industry; however the undesirable losses and waste rate that occur during peeling stage are always the main concern of food processing sector. There are three methods of peeling fruits and vegetables including mechanical, chemical and thermal, depending on the class and type of fruit. By comparison, the mechanical method is the most preferred; this method keeps edible portions of produce fresh and creates less damage. Obviously reducing material losses and increasing the quality of the process has a direct effect on the whole efficiency of food processing industry which needs more study on technological aspects of this industrial segment. In order to enhance the effectiveness of food industrial practices it is essential to have a clear understanding of material properties and behaviour of tissues under industrial processes. This paper presents the outlines of research that seeks to examine tissue damage of tough skinned vegetables under mechanical peeling process by developing a novel FE model of the process using explicit dynamic finite element analysis approach. In the proposed study a nonlinear model which will be capable of simulating the peeling process specifically, will be developed. It is expected that unavailable information such as cutting force, maximum shearing force, shear strength, tensile strength and rupture stress will be quantified using the new FEA model. The outcomes will be used to optimize and improve the current mechanical peeling methods of this class of vegetables and thereby enhance the overall effectiveness of processing operations. Presented paper will focus on available literature and previous works have been done in this area of research.
In-transit damage of tomatoes packaged in plastic crate and raffia basket was evaluated in cross- regional transportation trials undertaken from Kwana
Garfan (in Kano State) to Mile 12 market (in Lagos), Nigeria. Roma tomatoes were purchased from farmers and aggregated at a collection centre
located at Kwana Garfan. There, two 25-tonne trucks were loaded with wholesome tomatoes differently packaged in plastic crate and raffia basket.
Before departure to Lagos, samples of each filled container type were strategically positioned on the respective trucks. The commercial trips (from
Kwana Garfan to Mile 12) covered a distance of 998 km, taking two (2) days. At Mile 12 market (Lagos destination), in-transit damage in delivered
tomatoes was evaluated by sorting and separating damaged fruit within sample lots of each container type. Weights of damaged fruit in each sample
container were determined for each truck. Baskets incurred high in-transit damage of 34.72% to 49.78% (with 41.12% average). The use of plastic
crate reduced this damage to a level of 4.69 to 5.24% (with 4.92% average), thereby reducing damage in crates by 88%. In trucks, loaded in 5 basket
layers, high levels, 49.78% and 45.70%, of the total damage occurred at the bottom and topmost layers (first and fifth layers respectively) of tomato
baskets while lower damage levels of 37.4%, 36.72% and 37.9% occurred at the three middle layers (second, third and fourth layers) respectively. A
follow-up trial with a 20-tonne truck carrying baskets of tomatoes from Kaduna showed the same trend of fruit damage.
Keywords: Plastic crate, raffia basket, packaging, Roma tomatoes, in-transit damage, transportation
Finite element (FE) models of uniaxial loading of pumpkin peel and flesh tissues were developed and validated using experimental results. The tensile model was developed for both linear elastic and plastic material models, the compression model was developed only with the plastic material model. The outcomes of force versus time curves obtained from FE models followed similar pattern to the experimental curves; however the curve resulted with linear elastic material properties had a higher difference with the experimental curves. The values of predicted forces were determined and compared with the experimental curve. An error indicator was introduced and computed for each case and compared. Additionally, Root Mean Square Error (RMSE) values were also calculated for each model and compared. The results of modeling were used to develop material model for peel and flesh tissues in FE modeling of mechanical peeling of tough skin vegetables. The results presented in this paper are a part of a study on mechanical properties of agricultural tissues focusing on mechanical peeling methods using mathematical, experimental and computational modeling.
In South and Southeast Asia, postharvest loss causes material waste of up to 66% in fruits and vegetables, 30% in oilseeds and pulses, and 49% in roots and tubers. The efficiency of postharvest equipment directly affects industrial-scale food production. To enhance current processing methods and devices, it is essential to analyze the responses of food materials under loading operations. Food materials undergo different types of mechanical loading during postharvest and processing stages. Therefore, it is important to determine the properties of these materials under different types of loads, such as tensile, compression, and indentation. This study presents a comprehensive analysis of the available literature on the tensile properties of different food samples. The aim of this review was to categorize the available methods of tensile testing for agricultural crops and food materials to investigate an appropriate sample size and tensile test method. The results were then applied to perform tensile tests on pumpkin flesh and peel samples, in particular on arc-sided samples at a constant loading rate of 20 mm min(-1). The results showed the maximum tensile stress of pumpkin flesh and peel samples to be 0.535 and 1.45 MPa, respectively. The elastic modulus of the flesh and peel samples was 6.82 and 25.2 MPa, respectively, while the failure modulus values were 14.51 and 30.88 MPa, respectively. The results of the tensile tests were also used to develop a finite element model of mechanical peeling of tough-skinned vegetables. However, to study the effects of deformation rate, moisture content, and texture of the tissue on the tensile responses of food materials, more investigation needs to be done in the future.
