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1.
Oil extraction from confectionery, oilseed and wild sunflower seeds with n-hexane was investigated by laboratory tests carried out in a stirred batch extractor at several temperatures (40, 50 and 60 °C). The rates of extraction were determined from ground sunflower seeds (particle sizes between 0.420 and 1.000 mm). The oil yield in the extract increased with higher contact time and extraction temperature in all the cases. Equilibrium constants at 50 °C for different solvent-ground seed ratios are reported. A mathematical model of oil extraction from seeds of sunflowers, based on a modified diffusive process in spherical geometry of particles, was proposed. The analysis of significance of the coefficient of fitting regression models showed significant differences between temperatures for each genotype and between genotypes at each temperature. The resulting diffusion coefficient ranged from 1.34 × 10−12 to 1.87 × 10−12 m2/s for confectionery, 2.06 × 10−12 to 5.03 × 10−12 m2/s for oilseed, and 9.06 × 10−13 to 1.18 × 10−12 m2/s for wild sunflower. The temperature dependence of the diffusion coefficient was represented by an Arrhenius-type equation for each sunflower seed studied. Activation energy values of 13.74, 33.95 and 11.32 kJ/mol were obtained for confectionery, oilseed and wild sunflower, respectively.  相似文献   

2.
A water‐soluble gum was extracted from the endocarp capsule of the seed coat of Prosopis africana. The gum yield varied substantially with the method of dehulling. Maximum yield was obtained after boiling in 0.1 m Na2CO3 for 4 h. The effects of two different gum concentrations on the rheological properties of gum solutions were examined. The gum formed viscous solutions at low concentrations and exhibited stable viscosity in the pH range 6.0–8.0. Chemical analyses showed that the purified gum had a composition of 2.4% fat, 1.04% protein, 21.5% crude fibre and a gelation concentration of at least 10%. Galactose and mannose were the major polysaccharides identified. Large reductions in viscosity were observed with the addition of various concentrations of Na+ salts. The activation energies of flow for 2 and 3% gum solutions were in the range of 19.2–22.8 kJ mol?1 and were characteristic of systems with little intra‐ and intermolecular interactions.  相似文献   

3.
利用两种不同的培养基培养核盘菌,用离体叶片接种方法对40个不同向日葵品种进行室内抗性鉴定,结果表明:在Minimal medium培养基上生长的核盘菌和PDA培养基相比,菌丝的生长速度大大降低。菌株经PDA培养基培养接种向日葵叶片后,不同向日葵品种之间抗性水平没有显著差异;而用Minimal medium培养基培养的菌株接种供试的向日葵不同品种叶片后,品种间表现出一定的抗性水平差异。依据接种后不同品种抗性水平的差异将供试向日葵品种划分为三组,即:抗病品种如食葵765、油葵KS7等,共3份;耐病品种如3146、新葵杂5号等,共9份;感病品种如LD1093、新葵杂6号等,共28份。  相似文献   

4.
The aim of this study was to assess the potential activation of sunflower protein films with antioxidant and antimicrobial properties conferred by the phenolic compounds of sunflower seeds, which remain associated to the proteins used as starting material for film preparation. Two sunflower protein concentrates obtained from the residual pellet of oil industry were used, which had different content of phenolic compounds, mainly chlorogenic and caffeic acids. The film-forming dispersions and the films obtained were analyzed regarding their antioxidant properties (using ABTS, FRAP and PCL assays) and their antimicrobial properties (by agar disk diffusion tests). Phenolic compounds conferred important antioxidant properties to both dispersions and films, this activity being dependent on their content and their free or protein-bound nature. These compounds, however, did not confer their characteristic antimicrobial properties reported in previous studies, possibly due to their interaction with proteins and the pH of the film-dispersions. Since the antioxidant activity of phenolic compounds was preserved during the protein concentration process (inherent to the film formation), these protein matrices may be considered useful for protecting these bioactive compounds.  相似文献   

5.
Moisture-dependent properties of barnyard millet grain and kernel   总被引:1,自引:0,他引:1  
The geometric mean diameter, sphericity, grain surface area, 1000 grain mass, true density (toluene displacement method), terminal velocity, dynamic angle of repose, coefficient of internal friction, coefficient of static friction at different surfaces (sun mica, canvas and mild steel surfaces), specific deformation and rupture energy of the grain were found to increase 12.21%, 4.79%, 30.47%, 30.75%, 6.74%, 32.99%, 127.05%, 60%, 18.57%, 34–67%, 69.2% and 88.87% respectively at increase of moisture content from 0.065 to 0.265 kg kg−1 dry matter. However, true density (proximate composition method), bulk density, interstices and rupture force of grain was found to be decrease 8.64%, 20.1%, 86.49% and 21.17% respectively at increase of moisture content. Similar trend was observed for barnyard kernel also. True density (toluene displacement method) was found lower as compared to true density (proximate composition method) at all experimental moisture range indicated that the presence of void space inside the grain and kernel.  相似文献   

6.
以3个向日葵品种为材料,通过两年的田间试验研究向日葵群体的光合生理特征。结果表明,向日葵群体的叶面积指数(LAI)增长极快,出苗后第51d前后即达到最大值(LAImax)3.57~5.64。群体光合势与生物产量和子实产量呈极显著正相关。平均净光合率因品种和年份而异,范围在5.08~7.02g/m2.d。生物产量积累动态趋势为"慢-快-慢",符合Logistic方程。生物产量在各个器官中的分配比例一般为:茎秆(或子实)〉子实(或茎秆)〉叶片〉葵盘〉叶柄,子实所占比例即经济系数两年平均为29.7%和34.4%,因年份而异。早熟品种的经济系数大于中早熟和中熟品种。  相似文献   

7.
8.
9.
本研究以7个品种炒货葵花籽为研究对象,采用超声波从葵花籽仁提取油脂,用Schaal烘箱法进行加速氧化处理,比较加速氧化对不同品种葵花籽仁油脂过氧化值、酸值和碘值以及氧化后产生的共轭二烯与共轭三烯含量的影响,综合筛选出具有较高抗氧化稳定性的炒货葵花籽品种。结果显示,甘葵2号品种葵花籽仁油脂在氧化过程中过氧化值、酸值的变化量和氧化后产生的共轭二烯与共轭三烯的含量显著(p<0.05)低于其余各品种,碘值的变化量与LD5609、科阳7号葵花籽仁油脂无显著差异,但显著高于青花王、三道眉和青花品种,表明甘葵2号品种葵花籽抗氧化性较好。   相似文献   

10.
11.
The effect of sunflower head pith on the functional properties of emulsions was studied by using a model system. Oil/water (O/W) model emulsion systems were prepared from fresh and frozen beef by the addition of the pith at five concentrations. Emulsion capacity (EC), stability (ES), viscosity (EV), colour and flow properties of the prepared model system emulsions were analyzed. The pith addition increased the EC and ES and the highest EC and ES values were reached when 5% of pith added; however, further increase in the pith concentration caused an inverse trend in these values. Fresh beef emulsions had higher EC and ES values than did frozen beef emulsions. One percent pith concentration was the critic level for the EV values of fresh beef emulsions. EV values of the emulsions reached a maximum level at 5% pith level, followed by a decrease at 7% pit level.  相似文献   

12.
The contents of total and individual tocopherols of sunflower oils at different stages of industrial chemical and physical refining processes were determined by high-performance liquid chromatography (HPLC). According to the results, total and individual tocopherol contents gradually decreased until the end of the refining processes. The average losses of total tocopherol content during the chemical and physical refining processes were found to be 30.2% and 35.5%, respectively. The steam distillation stage of the physical refining process caused greatest overall reduction (average 24.6%) in total tocopherol content. In contrast to the physical refining process, the degumming-neutralizing stage in the chemical refining process caused greatest overall reduction (average 14.7%) in total tocopherol content. An additional average loss of 11.0% occurred during deodorizing in the chemical refining process. In both chemical and physical refining, the bleaching stage caused similar effects. The physical refining process caused higher loss in the total and individual tocopherol contents when compared with the chemical refining process. The conditions of the refining processes should be carefully evaluated to reduce the loss of tocopherols.  相似文献   

13.
Sunflower oil was added to cod gelatin in proportions of 0%, 0.3%, 0.6%, and 1% to improve the hydrophobic properties of the resulting films and decrease water vapor permeability and the soluble matter content. Mechanical and optical properties were evaluated to determine the influence of the added oil and the stability of the films during storage for one month. Adding oil increased film thickness, whiteness, optical absorbance and decreased transparency; all these properties held stable over the storage period. Fourier transform infrared (FTIR) spectra revealed some lipid–protein interactions (hydrogen bonds, ester formation) and early oil oxidation. By the end of storage oxidation was well advanced and secondary oxidation products were present. Adding oil in any quantity decreased the puncture force but not the puncture deformation. Stability of these two mechanical properties decreased during storage in the films that contained ?0.6% added oil. Water vapor permeability did not decrease when oil was added and even increased with storage time, though adding oil yielded more insoluble films due to lipid–protein interactions.  相似文献   

14.
The aim of this work was to study the formation of biodegradable films from sunflower protein isolates having different concentrations of phenolic compounds, which are present in sunflower seeds and are retained during the isolation of proteins from the residual pellet of the oil industry. Films were obtained by casting from aqueous dispersions of the isolates, using glycerol as plasticizer. Although proteins from different sunflower protein isolates presented different structural properties, such as surface hydrophobicity, the films obtained did not differ significantly regarding thickness (64–80 μm), density (∼1.47 g/cm−3), water content (∼25%), water vapor permeability (∼1.4 × 10−10 g H2O/Pa.s.m), mechanical properties (traction), glass transition temperature, or type of interactions involved in the protein network, which in all cases were mainly hydrogen bonds, hydrophobic interactions, and disulfide bonds. Sunflower protein films contained phenolic compounds had antioxidant activity. As the concentration of these compounds increased the films also presented increasing opacity and greenish tones, with absorption maximums at wavelengths similar to those of chlorophyll (which suggests their potential use in mulching for impeding weed growth).  相似文献   

15.
The amino acid composition, physicochemical and functional properties of grape (Vitis vinifera L.) seeds protein (GSP) were evaluated and compared with those of soybean protein isolate (SPI). Amino acid analyses of GSP revealed high levels of glutamic/glutamine, glycine and aspartic/asparagines. SDS‐PAGE analysis demonstrated that globulin was the major protein component in GSP, whose subunit molecular weights were mainly varied from 25.5 to 40.0 kDa. The isoelectric pH of GSP was found to be at the acidic pH of around 3.8. At all the pHs tested except pH 2.0, no significant changes of GSP secondary structure were observed. GSP exhibited beneficial functional properties such as preferable solubility and emulsifying activity, while the foaming properties and water holding capacity were relatively poor compared to SPI. It could then be employed to soup, sauce, beverage or meat product for improving nutritional and sensory quality of these foods at appropriate pHs.  相似文献   

16.
In this work, three heavy metals (HMs) cadmium, lead, and zinc were determined in 16 newly breaded varieties of sunflower seed oil, using atomic absorption spectrometry, prior to use of microwave-assisted acid digestion method (MWD). The accuracy of the proposed method was studied by standard addition method and values obtained by conventional wet acid digestion methods (CAM) on same samples. The detection limit obtained from the standard addition curve was 0.327, 3.38, 10.0 ng/ml for Cd, Pb, and Zn, respectively, with high percentage recoveries. Multivariate statistical techniques (cluster and principal component analysis) were applied to modeling classes of different varieties of sunflower seed oils grown in same agricultural plot, on the basis of the analytical data of HMs. The results obtained providing sufficient information on tolerable limit of all three HMs by different varieties of sunflower oil to grow safely.  相似文献   

17.
18.
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.  相似文献   

19.
Cookies prepared with white or wholegrain wheat flours and substituted with high-oleic sunflower seed (10 g/100 g and 30 g/100 g supplementation levels) and hull-less barley flour (30 g/100 g and 50 g/100 g levels) were evaluated for nutritional properties, physical and sensory attributes. Sunflower seed significantly increased the contents of Se, Zn, Mg, and Ca, as well as the contents of α-tocopherol and fat in cookies. The contents of Se, Cu, Fe, Zn and β-glucan were raised in cookies by barley supplementation. It was estimated that 100 g of barley and sunflower seed-supplemented cookies can meet about 18–49% of dietary reference intake (DRI) for Se. Both supplemented cookies were found not to pose a significant risk, with regard to excessive intakes of heavy elements (Pb, Cd, As, Hg). In addition, the supplementation with sunflower seed improved sensory properties of the cookies.  相似文献   

20.
The fatty acid composition of sunflower (Helianthus annuus L ) seed oil was shown to respond to N supply rates and the time of N application in four glasshouse and two field experiments using five cultivars. Changes in individual fatty acids % total were smaller than those caused by differences in minimum temperatures during seed development but they were statistically significant. N supply rates before floret initiation affected the % fatty acid composition of mature seeds; the percentage of palmitic (16:0) and linoleic (18:2) acids responded positively to increases in N supply whereas % stearic (18:0) and oleic (18:1) acids responded negatively. The only fatty acid to respond to N supply rates between floret initiation and anthesis was 18:0 acid. The percentage of 18:1 responded positively and that of 18:2 acid negatively to high N supply rates after anthesis Responses to single N applications at different stages of plant development in the field confirmed these findings but results were more variable than in the glasshouse. Partial or complete defoliation at anthesis in the field caused the same changes in fatty acid composition as did a low N supply after anthesis. The results are difficult to interpret in terms of our current knowledge of lipid biosynthesis. N supply rates may affect the rate of hydrolysis of fatty acid complexes or their transport from the proplastid to the cytosolic compartment. There was no compelling support for the hypothesis that N supply rates bejore floret initiation were affecting fatty acid composition through their effects on other plant characters such as leaf mass, seed number or single seed weight.  相似文献   

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