Mechanical stress on canola seed during dehulling

The mature canola seed comprises an embryo, a group of structures that have a high content of protein and oil, and a fibrous seed coat held together by endosperm tissues. High-quality canola meal production requires removal of fiber-rich seed hull that typically contributes little nutrient value. Canola hull accounts for more than 70.0% of the insoluble fiber within the seed, which limits its uses as feed. Dehulling canola seed, before oil extraction, increases the protein content and decreases fiber content in the meal, to up to 50.0% and to down to 10.0%, respectively. Due to the complexity in dehulling canola seeds, several methods have been explored by the canola processing industry. However, little research has been conducted in analyzing the effects that mechanical dehulling methods have on seeds. In this study, we conducted mechanical tests to characterize seed behavior and hull fracture under uncoupled stresses such as compression and shear;stresses generated by the common dehulling equipment used in the industry, such as mills. All tests were carried out on single seeds at different moisture contents, from 5.00% to 25.0% wet mass basis (w.b.). Over a range of moisture contents studied, shear loading mode limited deformation of embryos in comparison to compression loading. Additionally, hardness tests were performed with a nano-indenter machine to determine seed hull properties. The overall results from these experiments provided information used to construct a computational model that represents canola seed deformation under compression stress.     

Moisture content/relative humidity equilibrium of high-oil and confectionery type sunflower seed

Adsorption and desorption moisture equilibrium (m.c./e.r.h.) was determined for high-oil and confectionery type sunflower seeds. The seeds were exposed to various relative humidities which were controlled with environmental chambers. The equilibration data for both seed types were determined at 10 and 20°C. The two seed types yielded almost identical adsorption and desorption moisture curves at 10°C which indicated that seed physical and chemical properties had little effect on m.c./e.r.h. at this temperature. The “hysteresis effect” was evident at 10°C, desorption equilibrium moisture levels being higher than adsorption for both seed types. There was no apparent “hysteresis effect” in seed equilibrated at 20°C. At the higher temperature, the confectionery seed equilibrated to higher moisture levels than did the high-oil type, thus hull to kernel weight ratio, hull thickness, and oil content could affect m.c./e.r.h. at 20°C     

Preparation and application of vegetable proteins, especially proteins from sunflower seed, for human consumption. An approach

About 80% of the world protein production are of vegetable origin. More than half the vegetable protein is fed to animals, whereas merely 10 kg protein per capita are obtained from meat, milk and eggs per year. Therefore, and because of rising prices for raw materials and energy the production and the firsthand utilisation of proteinacous plants for foodstuffs are a worldwide problem. As future source of protein for human nutrition sunflower seed and oil extraction residues from sunflower seed, respectively, are of great significance. Sunflower seed does not contain anti-nutritive and toxical compounds. After crossing of species having a high oil content, the today cultivated sunflower hybrids bring seeds containing 17-22% crude protein and 30-52% oil. The cultivation also has led to a considerable reduction of the hull content. In processing of sunflower proteins colour problems occur resulting from finely ground particles of dark hulls and from polyphenolic acids which are easily oxidized and converted into brown polymerics. Essential components of the sunflower protein production are, therefore, the at least 98% dehulling before processing as well as the separation of polyphenolic acids and/or the prevention of their oxidation. In principle, the variation and combination of technological steps in pre-treating and defatting of sunflower seed, in extracting, precipitating, washing and drying of proteins, the chemical modification of proteins obtained, the interaction with neutral salts or complexing agents, and the admixture of lysine or proteins of high lysine content allow to adapt sunflower proteins to each type of application.     

Physical Properties of Guar Seeds

A study on the guar seeds (Cyamopsis tetragonoloba) was performed to investigate the effect of moisture content on the selected physical properties. Moisture contents of seeds were varied from 5.2% to 25.0%, dry basis (d.b.). Seed geometric parameters, such as average length, width, thickness, geometric-mean diameter, surface area, volume, increased but sphericity decreased with increase in moisture content. The 1,000-seed mass increased linearly with moisture content. Bulk density of guar seeds decreased linearly when moisture content was raised from 5.2% to 25.0% d.b. On the other hand, true density decreased till moisture content was increased up to 20%. Further increase in seed moisture resulted in increased true density, which has not been observed in other food grains. The porosity decreased till seed 15.3% moisture and then increased with further addition of moisture. Angle of repose, coefficients of static friction on three different surfaces (plywood, mild steel, and galvanized iron), and terminal velocity increased linearly with seed moisture content.     

基于含水率的无患子物理性质的测定

为了给无患子加工机械的研发提供设计依据和理论基础,需要对无患子的物理特性及机械特性进行研究,如无患子的三维尺寸、含水率、千粒重、密度、孔隙率、静摩擦系数等,并研究一些物理性质随含水率的变化关系。结果表明:无患子果及无患子种子的三维尺寸、粒子密度、体积密度、无患子果皮及无患子种子与其他材料的静摩擦系数随含水率的升高而增大;无患子果及无患子种子的孔隙率、无患子种子(除长度方向)的压缩破坏载荷随含水率的升高而减小。     

Determination of caffeic and chlorogenic acids and their derivatives in different sunflower seeds

Five different genotypes (Tesoro, Marko, Clip, Vyp‐70 and Nanta) of sunflower seeds were studied and the phenolic compositions of their kernel and hull were characterised by HPLC and MS techniques. The main phenolic compounds present in both the kernel and hull are chlorogenic acid, caffeic acid and two caffeoylquinic derivatives. Both derivatives were characterised by partial alkaline hydrolysis and LC/MS. The four phenolic compounds present in the kernel ranged from 94.6% (genotype Clip) to 99.3% (genotype Marko) of the total phenolic compounds of the whole seed. Therefore the dehulling of the seed scarcely improves its nutritional value. © 2000 Society of Chemical Industry     

Studies of the physico-chemical properties and polyphenoloxidase activity in seeds from hybrid sunflower (Helianthus annuus) varieties grown in India

Physico-chemical properties and polyphenol oxidase (PPO) activities of seven hybrid sunflower varieties commonly grown in Punjab state of India were studied. Seeds were studied for variations in physico-chemical properties, 100 kernel weight, density, bulk density, moisture, hull, oil, protein and ash content; expelled cake was studied for moisture, oil, crude fibre, ash and protein content and expelled-defatted cake for acid detergent fibre, lignin, moisture, ash and protein contents. PPO activity in all varieties, determined using pyrogallol as substrate at pH 6.5, varied between 0.212 and 0.294 Ab/min/mg protein. The PPO enzyme activity for MSFH-8 and Mega-363 was observed to be maximum at 55 and 60°C, respectively. The enzyme showed a K_m value between 1.01 and 1.968 mM for pyrogallol and V_max value between 0.21 and 2.0 Ab/min. ©     

Effects of Hull Scratching,Soaking, and Boiling on Antinutrients in Japanese Red Sword Bean (Canavalia gladiata)

The effects of hull processing, soaking, and boiling on the content or activity of antinutrients in the red sword bean (RSB; Canavalia gladiata) were investigated. RSB seeds were compared with kidney bean (KB; Phaseolus vulgaris) seeds that are starch based and often used as processed products in Japan. RSB seeds had higher weight, thicker hull, and higher protein content, but lower moisture content compared with KB seeds. Because of the strong and thick hull, the relative water absorption of untreated RSB seeds was very low after soaking. Seeds were soaked after dehulling, scratching, and roasting. The results showed that hull scratching was the optimal method for increasing water absorption during soaking compared with dehulling and roasting. After soaking, the water used for soaking was discarded, since it had a high content of polyphenols and bitter taste, and RSB seeds were boiled in fresh water for 20, 40, and 60 min. The results showed that polyphenol and tannin contents, antioxidant activity, and hemagglutinating activity, as well as maltase, sucrase, and trypsin inhibitor activities in scratched RSB seeds decreased significantly after boiling compared with those in raw seeds, whereas amylase inhibitor activity showed no significant change. Overall, it was concluded that the combination of hull scratching, soaking, and boiling in fresh water can reduce thermal‐stable or sensitive antinutrients in RSB and thus, significantly improve its nutritional value.     

Assessing mineral composition and morpho-physiological properties of de-hulled einkorn wheat during storage at different moisture levels

In this study were investigated the effects of different moisture levels (4.8, 9.5, 13, 16.7 and 20%, w.b.) during the storage at 10 °C for three months on some mineral compositions and morpho-physiological properties as dimensional (length, width, thickness, arithmetic mean diameter, geometric mean diameter, surface area and volume, sphericity), gravimetric (thousand grain weight, bulk and true densities) and the seed (colour measurement and electrical conductivity) of de-hulled einkorn wheat seeds. Mineral composition of wheat seeds changed with increasing moisture level. In particular, decreases in mineral composition were observed above 16.7% moisture level. Dimensional properties showed increases depending on increased moisture level. It was found that thousand grain weight and true density values increased with increase in moisture level. However, bulk density values were found to decrease with increase in moisture level. The seed colour properties as L*, a*, b*, Chroma, hue angle and Browning index did not change statistically at the end of three months storage with increase at moisture level. The results showed that mineral compositions and functional properties of seeds at moisture level of 9.5% is more suitable than other moisture levels. As a result, high moisture levels during storage can cause degradation of seed quality.     

Splitting and dehulling lentil (Lens culinaris): Effects of seed size and different pretreatments

A conservative estimate of 800 000 T of red-cotyledon microsperma lentil (Lens culinaris Medikus) is consumed annually after postharvest processing into split dehulled seed. This process consists of cleaning the seed of foreign matter, brief immersion in water, spin-drying, standing to temper, separation into seed size fractions, dehulling/splitting and final separation. The effects of seed size (4 and 4.5 mm fractions), immersion times (1, 5, 10 and 30 min), temperature (19° and 36°) and duration (0, 30, 60 and 120 min) of air drying, and tempering time (0 and 24 h), on the efficiency of dehulling and splitting lentil were examined. Dehulling efficiency (%) was estimated as the sum of split dehulled seed, whole dehulled seed, and whole hulled seed (whole seeds are separated for recycling to the dehuller). Dehulling efficiency was best with the small seed fraction (4 mm), an immersion time of 1 min, no air drying, and a tempering time of 24 h. The drying air temperature did not have a significant effect on dehulling efficiency. Dehulling efficiency was highest with a low seed moisture content.     

Life history of Plodia interpunctella Hübner on sunflower seeds: Effects of seed qualitative traits and the initial seed damage

Sunflower seeds are regularly infested by Plodia interpunctella during storage. Although this pest prefers damaged seeds, in practice it can infest undamaged seeds as well. This research assessed the influence of the sunflower seed type (oil, protein for human consumption and bird-feed) and the initial seed damage during post-harvest processing (dehulled kernels, 10, 20, 30% of damaged seeds and undamaged seeds) on development of P. interpunctella (larval mortality, larval development, mean developmental duration, adult emergence and fecundity). Biochemical analysis of seeds, kernels and hulls detected the highest content of phenols in the seed and hull and tocopherols in the kernel of the oil type hybrid. The antioxidative activity was the highest in the seed, kernel and hull of the protein type for bird feed. The shortest development (39.5 days) and the highest fecundity (91.3) were on the oil type seeds, while the longest development (42.1 days) and the lowest fecundity (68.1) were on the seeds of the protein type for bird feed. The highest mortality of larvae was on the undamaged seeds of the protein type for bird feed and human consumption (21.3% and 14.0%, respectively). The type of sunflower and the level of initial damage affected larval mortality, developmental duration and fecundity. The mean developmental duration and the number of emerged adults were dependent only on the initial seed damage. Principal component analysis detected strong positive correlation between mortality and development with the tocopherol content on the undamaged seeds while fecundity was associated with the state of kernel and the amount of tannins, proteins and oil content in the seed. The undamaged seeds of the protein type for the bird feed were the least suitable for the development of this pest, while the oil type kernels were the most suitable.     

Status of pulse milling processes and technologies: A review

Pulses are essential component of the human diet in the underdeveloped and the developing countries. Pulse milling mainly focuses on complete removal of the hull with minimum generation of powder, broken, and in certain cases dehulled split formation. Physical and mechanical properties of different pulses are described and their role in dehulling is discussed in this review. The review discusses nature of gums that binds hull and cotyledons together and their effect on milling characteristics. Pitting operation is performed for all pulses prior to the pretreatment for better dehulling. Various pretreatment processes (soaking, edible oils, chemicals, enzymes, hydrothermal) developed to loosen the bond are examined for their dehulling efficacy from commercial application viewpoint. Dependence of dehulling characteristics of different pulses on size, shape, variety, grain hardness, and moisture content are discussed. Most of the machines developed for pulses dehulling in India are abrasion based emery-cylinder concave system. The studies done for optimization of different pretreatment process conditions are also reviewed. The losses taking place in the form of broken and powder during pulse milling are described. Methods for performance evaluation of the pulse dehulling system are reviewed and expressions are suggested for proper evaluation. This review gives complete overview of the processes and technological status of pulse milling in present context.     

Radio Frequency Dielectric Properties of Bulk Canola Seeds under Different Temperatures,Moisture Contents,and Frequencies for Feasibility of Radio Frequency Disinfestation

The parallel capacitances and resistances of the bulk canola seeds were measured to determine the dielectric properties of canola seeds using a radio frequency dielectric fixture at different levels of temperature (30–80°C) and moisture content (5–11% w.b.), over the frequency range of 5 to 30 MHz. The dielectric constant (ε′) increased from 3.82 to 7.85 with increasing temperature and decreasing frequency regardless of the seed moisture contents. The dielectric loss factors (ε”) of the bulk seeds increased with increasing temperature and moisture content and decreased with frequency, ranging between 0.11 and 13.0. The penetration depth of the electromagnetic power in the bulk seeds varied from 1.30 to 48.0 m depending upon temperature, frequency, and moisture content. The distinct correlation of sensitivity of dielectric properties with moisture content was not observed except for that of penetration depth. The dielectric properties of the bulk canola seeds were higher than those of other oil seeds at various moisture contents; it might be affected by relatively higher linolenic acid content among other fatty acids. The large difference of the dielectric loss factors of insect pests cf. those of canola seeds showed potential for radio frequency disinfestation based on selective heating of insect pests in the canola seeds. The dielectric properties determined can be used for simulating temperature distribution within the bulk canola seeds during the radio frequency process.     

The moisture dependent physical and mechanical properties of whole lentil pulse and split cotyledon

Some physical and mechanical properties of lentil whole grain/pulse and dhal (dehusked split pulse), at different moisture contents were determined. Among the physical properties, size, sphericity, roundness, average surface area, bulk density and void fraction were determined. Bulk densities of whole pulse were between 785 and 831 kg m^?3, whereas for dhal they were between 741 and 840 kg m^?3 and bulk density decreased as moisture content was increased for both the whole grain and the dhal. The compression behaviour was judged by determining the firmness and the linear elastic limit, of which the former decreased with moisture content but the linear elastic limit increased. A method is proposed to calculate the total surface area of dhal and whole pulse. Photomicrographs showed the thickness of the outer seed coat to be between 25 and 65 microns.     

Effect of Moisture Content on Pitting and Milling Efficiency of Pigeon Pea Grain

Pitting is a premilling operation in which pigeon pea grain is passed through a dehulling machine quickly to crack the hull or partly dehull the grain. A study was conducted to investigate the effect of grain moisture content on pigeon pea hull during pitting. Pitting of the grain was done at 6%, 8%, 10%, 12%, and 14% moisture contents using dhal mill developed by Central Institute of Agricultural Engineering, Bhopal (India). Grains having a cracked hull or partly dehulled during pitting varied from 35.3% to 85.3% with maximum value at 10% moisture content and reduced with an increase in moisture content. Maximum finished product in the form of dehulled whole (gota) and dehulled splits (dhal) was also obtained at 10% moisture content. Pitted grains of pigeon pea were treated with 0.28% cottonseed oil to study the effect of moisture content and pitting on dehulling efficiency, which was maximum (86.7%) at 10% moisture content.     

Effect of pectinase on the oil solvent extraction from different genotypes of sunflower (Helianthus annuus L.)

Pectinase-assisted solvent extraction of oil and total tocopherol from sunflower hybrids with different structural characteristics was studied by means of laboratory tests carried out in a stirred batch extractor at 50 °C. From the oil yield results obtained for the two hybrids studied, black-hull (P20) and striped-hull hybrids (ACA 884), it could be observed that oil was extracted at different rates in both hybrids. Analyzing the performance data versus time in the control samples, ACA 884 oil was released more easily and remained invariant with time, whereas for P20 the extraction was slower and the maximum value was reached at 60 min. The fiber wall structure collapsed by the enzymatic action, improving oil release and allowing a faster extraction. The efficiency of the treatment was measured in terms of the percentage of increase in oil yield compared with the control samples. It was observed that in hybrid ACA 884 the mean increases were not significantly different (p = 0.9295) over time (4.12% d.b.). Hybrid P20 showed a significant increase in the percentage of oil yield (p = 0.0001) at 10 min (10.85% d.b.), and then it remained virtually constant over time (4.89% d.b.). The black-hull hybrid (P20) presented significant differences in fatty acid composition due to the enzymatic action. Pectinase treatment was highly effective in the tocopherol extraction from hybrid P20 (p < 0.001), obtaining a 32.3% increase on average. The maximum values were 662 and 220 μg g dried ground seed⁻¹ at 60 and 120 min for black-hull and striped-hull hybrids, respectively. The enzymatic treatment effectively produced an increase in oil and tocopherol yields for the black-hull hybrid.     

Predicting Guar Seed Splitting by Compression between Two Plates Using Hertz Theory of Contact Stresses

Hertz's theory of contact stresses was applied to predict the splitting of guar seeds during uni-axial compressive loading between 2 rigid parallel plates. The apparent modulus of elasticity of guar seeds varied between 296.18 and 116.19 MPa when force was applied normal to hilum joint (horizontal position), whereas it varied between 171.86 and 54.18 MPa when force was applied in the direction of hilum joint (vertical position) with in moisture content range of 5.16% to 15.28% (d.b.). At higher moisture contents, the seeds yielded after considerable deformation, thus showing ductile nature. Distribution of stresses below the point of contact were plotted to predict the location of critical point, which was found at 0.44 to 0.64 mm and 0.37 to 0.53 mm below the contact point in vertical and horizontal loading, respectively, depending upon moisture content. The separation of cotyledons from each other initiated before yielding of cotyledons and thus splitting of seed took place. The relationships between apparent modulus of elasticity, principal stresses with moisture content were described using second-order polynomial equations and validated experimentally. Practical Application: Manufacture of guar gum powder requires dehulling and splitting of guar seeds. This article describes splitting behavior of guar seeds under compressive loading. Results of this study may be used for design of dehulling and splitting systems of guar seeds.     

Heated-air drying of oilseeds

This paper describes experimental work on the drying of oilseeds. Resistance to air flow and drying rates, parameters needed for oilseed drier design, were measured. Safe drying temperatures were deter,ined in a small batch fluidized bed. Some sealed tube heating tests were also perforrned for comparison. Quality assessment was based on the effect of drying conditions on the germination of the seed and on the free fatty acid content and peroxide value of the extracted oil. Colour of the oil was also measured before and after a heat bleach test using a photometric method.Quality results indicate that germination is affected by heat above a critical drying air and seed temperature. For sunflower seed, safe drying air temperatures of 65, 60 and 55°C were obtained for initial moisture contents of 12, 14 and 16% respectively. For rapeseed, an inlet air temperature of 60°C caused no loss of germination for each initial moisture content. However, sealed tube heating of 16% m.c. sunflower and rapeseed at 60°C for 4 hr completely killed the seeds. Free fatty acid content and peroxide value were not significantly changed by the heat treatments in all cases, and oil colour after heat bleaching generally showed some improvement up to an air temperature of 70°C. At 80°C, however, substantial darkening of sunflower oil was observed.     

不同含水量下黔江肾豆加工物理特性研究

主要研究了含水量在5.0%至35.0%范围内7个梯度水平下的黔江肾豆的各项物理特性,以期为黔江肾豆的实际生产加工、后续的开发研究及其他研究分析提供所需的籽粒物理性质数据参考。主要研究测定不同含水量下黔江肾豆的各项物理性质,包括:粒径、圆球度、体积、表面积、千粒重、容重、真实密度、孔隙率、休止角、静摩擦系数等。结果表明,除圆球度外,各项物理性质受水分含量影响均显著。随着含水量的增加,容重值降低;摩擦系数随含水量增加而增大,同时又与接触表面性质相关,木质横纹>木质直纹>钢>铝;其他各物理特性值均升高。     

Mass-Volume-Area Related and Mechanical Properties of Soybean as a Function of Moisture and Variety

Selected physical properties of three varieties of soybean were determined within a moisture content range of 6.25 to 11.60% dry basis. The seed length, width and thickness for the three varieties increased with the increase in moisture content while the sphericity and roundness of the three varieties increased within the range of 43.0 to 72.3% and 45.5 to 75.9% respectively. True density, bulk density and porosity decreased with increase in moisture content within the range of 1203 to 964 kgm^?3, 809 to 740 kgm^?3 and 0.35 to 0.22. The coefficient of friction also decreased with increase in moisture and the highest and lowest value was 23.7 and 17.3 on plywood while that on glass was 19.8 and 11.6, respectively. The angle of repose and terminal velocity increased within the range of 10.2° to 15.3° and 10.10° to 12.60 m/s for the varieties. The compressive force however decreased and the highest and lowest value was 12.85 and 3.5 N respectively for the three varieties.