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1.
Popping characteristics, specifically expansion volume and popping time, were studied for damaged popcorn. A single variety of commercial undamaged yellow popcorn was separated into four size fractions (D < 4.36, 4.36 < D < 5.16, 5.16 < D < 5.95, and D > 5.95 mm) by screening with round-hole sieves. Kernels were damaged using a razor knife by either slicing a 2-mm diameter piece of the endosperm or the germ or by cutting through the pericarp and seed coat into the endosperm or the germ ≈2 mm. A total of five combinations of location and damage were studied (tip cap removed, side cut, side sliced, germ cut, and germ sliced) for each kernel size. A control sample with no damage was also analyzed for each size fraction. All of the damaged kernels (regardless of type of damage) popped, but they had expansion volumes 9.1–47.5% smaller than those of undamaged kernels. The expansion volume of damaged kernels increased by 52.5–85.7%, depending on the damage, when the size of the kernel increased from <4.36 mm to >5.95 mm. Removing the tip cap and slicing through the germ caused less loss of expansion volume than did other types of damage. Damaged popcorn kernels had faster popping times (12.2–24.0 sec) than did undamaged kernels (30.9–34.6 sec). Popping times increased with increasing kernel size for all types of damage. 相似文献
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玉米果穗表型性状是玉米育种、产量预测的重要参数,提出一种基于穗粒分布图的玉米果穗性状计算方法,全面解析玉米果穗和穗粒的几何、数量和颜色等表型性状。该文利用步进电机驱动果穗转动来获取果穗主要侧面图像,采用果穗畸变校正方法生成标准果穗图像序列,在像素尺度进行果穗轮廓分析,建立图像序列中果穗轮廓映射关系并生成果穗三维模型,在穗粒尺度拼接果穗整个表面的穗粒分布图,计算出果穗和穗粒的各项表型性状。试验结果表明,提出的表型性状计算方法对穗型及穗粒分布规则的玉米果穗具有较高检测精度,其中穗行数、行粒数、总粒数、果穗长和果穗粗的平均计算精度分别为98.231%、94.351%、96.921%、98.956%和98.165%。 相似文献
4.
J. L. Fernndez‐Muoz Isela Rojas‐Molina M. L. Gonzlez‐Dvalos Myriam Leal M. E. Valtierra E. San Martín‐Martinez M. E. Rodríguez 《Cereal Chemistry》2004,81(1):65-69
Our report shows the calcium ion diffusion process through the different parts of maize kernels (pericarp, endosperm, and germ) during the traditional nixtamalization process as a function of steeping time (t) 0–24 hr. The cooking step of the nixtamalization process used 3 kg of maize kernels in 6L of water and 2% calcium hydroxide (w/w). The cooking temperature was 92°C for 40 min. The calcium content of the samples was measured using atomic absorption spectroscopy. We found that the whole instant corn flour, pericarp, endosperm, and germ, had a nonlinear relationship to steeping time, showing a local maximum at 9 hr. Analysis of the different parts of the nixtamalized kernels showed that in short steeping times (0–5 hr) calcium diffusion took place mainly in the pericarp. Calcium diffusion in the endosperm and germ occurred gradually over longer steeping times. However, the physical state of the kernels (broken kernels) accelerated the diffusion process. Calcium diffusion occurred first in the pericarp, followed by the endosperm and germ. Immediately after cooking (t = 0 hr), we found a 1.148% calcium content in the pericarp, 0.007% in the germ, and 0.028% in the endosperm. After 24 hr of steeping, the calcium contents were 2.714% in the pericarp, 0.776% in the germ, and 0.181% in the endosperm. In another study, the calcium content in the endosperm was measured by first separating the 10% from the outermost, followed by another 10% from the next endosperm tissue, and concluding with the remaining 80%. Calcium ions were present mainly in the outermost layers of the endosperm. The damaged kernels steeped for more than 5 hr showed greater calcium concentrations than the undamaged counterparts. 相似文献
5.
基于全景图像的玉米果穗流水线考种方法及系统 总被引：1，自引：1，他引：0
为提高玉米果穗考种效率和精度,该文提出一种基于全景图像的玉米果穗流水线考种方法和系统。利用托辊传送装置实现果穗自动连续推送,基于工业相机自动检测果穗运动状态并实时采集图像,获取覆盖果穗全表面的图像序列;建立果穗运动、摄像机成像、表面拼接关系,从图像序列中抽取果穗中心畸变最小区域拼接出果穗表面全景图像;最后,结合果穗边界检测、籽粒分割和有效性鉴定等技术提取出果穗表面上有效籽粒。试验结果表明,该文方法和系统较好地平衡了玉米果穗考种的效率和精度,图像采集和计算平均效率达15穗/min和4穗/min,穗长和穗行数指标计算精度可达99%和98.89%,可为研发全自动、高通量玉米果穗表型检测装置提供有益借鉴。 相似文献
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Seven wheat cultivars with different starch contents were used as materials to investigate the distribution of grain starch granule size under irrigated and rainfed conditions. In mature grains, the diameter of starch granules was 0.37–52.6 μm, and the percent volume distribution showed a two‐peak curve with the mean particle diameter of 5 (B‐type) and 25 μm (A‐type) at each peak. The volume percentages of A‐ and B‐types were 52.7–65.5% and 34.5–47.3%, respectively. A two‐peak curve is also shown in percent surface area distribution of starch granules, but only one peak in percent number. Both irrigated and rainfed conditions had a significant effect on the starch granule size distribution of the seven cultivars. As compared with irrigated treatment, rainfed treatment affected the distribution of starch granules in grains of all cultivars through increasing the volume percentage and surface area percentage of 2–9.8 and <9.8 μm starch granules and decreasing those of >9.8 and >18.8 μm starch granules. The soil water deficit also decreased the contents of amylose and starch in grains and increased protein content, indicating that different water regimes had an evident effect on grain quality. According to correlation coefficients (r), the contents of amylose, starch, and protein in grains was significantly correlated with the volume percentage of starch granules with different diameter ranges. 相似文献
7.
玉米秃尖与内源激素的关系 总被引：6，自引：1，他引：5
玉米果穗顶部不能形成种子或部分种子败育而导致秃尖,秃尖受遗传影响较大,并对光合作用的依赖性很强。本文以20个玉米杂交组合雌穗顶部穗轴为材料,对光合作用的"源"和"库"起调控作用的顶部穗轴内源激素与其秃尖长度的关系进行了研究。结果表明,在快速灌浆期,玉米雌穗顶部穗轴GA3I、AA、CTK含量较高,而ABA含量很低;ABA含量与玉米秃尖长度呈极显著的正相关;(GA3+IAA+CTK)/ABA含量与玉米秃尖长度呈极显著的负相关。说明顶部穗轴ABA含量的高低与玉米秃尖长度存在密切关系。 相似文献
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Thermal decomposition of corn starches with different amylose to amylopectin ratios (0:100 waxy, 23:77 maize, 50:50 Gelose 50, 80:20 Gelose 80) were studied by thermogravimetric analysis (TGA) in an open system and differential scanning calorimetry (DSC) in a sealed system using stainless steel high‐pressure pans with varying water content (9–75%). The initial water content did not affect the decomposition temperature in the open system because all water evaporated from samples before reaching the decomposition temperature. The sequence of decomposition temperature of different starches is waxy > maize > G50 > G80 in an open system. The moisture content in starch remains constant during the degradation process in a sealed system. Two decomposition temperatures were observed in the sealed system: the first at lower temperature represents long chain scission and the second at higher temperature involves decomposition of the glucose ring. The sequence of the first degradation is waxy > maize > G50 > G80. There is no observable difference of the second degradation for the samples containing different amylose to amylopectin ratios. The higher the moisture content, the lower the second decomposition temperature. Decomposition of glucose was used to confirm the mechanisms proposed for the starch degradation. 相似文献
9.
Ernesto David Narvez‐Gonzlez Juan de Dios Figueroa‐Crdenas Suketoshi Taba Eduardo Castao Tostado Ramn lvar Martínez Peniche Froyln Rincn Snchez 《Cereal Chemistry》2006,83(6):595-604
Chemical composition (moisture, total lipids, protein, and apparent amylose) and some physical features (1,000 kernel weight, hardness, and anatomical composition) were determined in 71 accessions representing races of maize from Latin America. Their microstructural characteristics (size and compaction of endosperm cell bodies, pericarp thickness, horny‐floury endosperm ratio, and morphology and size of starch granules) were also evaluated using environmental scanning electron microscopy (ESEM). Compaction was the most important microstructural feature of the maize kernels, representing kernel hardness. Highly compact kernels tended to be hard, with high protein, pericarp, and hard‐endosperm content and high pericarp thickness, but with low moisture, amylose content, and kernel weight and size. The opposite was observed in the least compact kernels. Highly compact kernels tended to have small, polygonal starch granules (<10 μm), while the least compact kernels contained large, spherical granules (>10 μm). These results suggest that microstructure is responsible for the physical features of maize kernels and that microstructure is related to chemical composition. 相似文献
10.
Floyd E. Dowell Tom C. Pearson Elizabeth B. Maghirang Feng Xie Donald T. Wicklow 《Cereal Chemistry》2002,79(2):222-226
Reflectance and transmittance visible and near‐infrared spectroscopy were used to detect fumonisin in single corn kernels infected with Fusarium verticillioides. Kernels with >100 ppm and <10 ppm could be classed accurately as fumonisin positive or negative, respectively. Classification results were generally better for oriented kernels than for kernels that were randomly placed in the spectrometer viewing area. Generally, models based on reflectance spectra have higher correct classification than models based on transmittance spectra. Statistical analyses indicated that including near‐infrared wavelengths in calibrations improved classifications, and some calibrations were improved by including visible wavelengths. Thus, the color and chemical constituents of the infected kernel contribute to classification models. These results show that this technology can be used to rapidly and nondestructively screen single corn kernels for the presence of fumonisin, and may be adaptable to on‐line detection and sorting. 相似文献
11.
C. Zazueta G. Ramos J. L. Fernndez‐Muoz M. E. Rodríguez G. Acevedo‐Hernndez R. C. Pless 《Cereal Chemistry》2002,79(4):500-503
The entry of calcium ions from the nixtamalization solution into maize kernels over time was followed in model experiments using radiolabeled calcium ions, with autoradiographic evaluation of the kernels after different cooking and steeping times. Calcium ions immediately entered the pericarp and were rapidly fixed at the outer boundary of the endosperm, especially at the external surface of the germ. Entry of calcium into the endosperm occurred gradually after long steeping times, except in the case of broken kernels, for which massive invasion by calcium was observed. After extended steeping times, a moderate amount of calcium‐45 was evident in the germ. Specific perforation of the outer layers of the grains provided a defined route of facilitated entry of calcium into the endosperm. No fundamental difference with respect to penetrability by calcium ion was seen in a comparison between flint‐type grains and grains containing only floury endosperm. 相似文献
12.
A high‐speed dual‐wavelength sorter was tested for removing corn contaminated in the field with aflatoxin and fumonisin. To achieve accurate sorting, single kernel reflectance spectra (500–1,700 nm) were analyzed to select the optimal pair of optical filters to detect mycotoxin‐contaminated corn during high‐speed sorting. A routine, based on discriminant analysis, was developed to select the two absorbance bands in the spectra that would give the greatest classification accuracy. In a laboratory setting, and with the kernels stationary, absorbances at 750 and 1,200 nm could correctly identify >99% of the kernels as aflatoxin‐contaminated (>100 ppb) or uncontaminated. A high‐speed sorter was tested using the selected filter pair for corn samples inoculated with Aspergillus flavus; naturally infested corn grown in central Illinois; and naturally infested, commercially grown and harvested corn from eastern Kansas (2002 harvest). For the Kansas corn, the sorter was able to reduce aflatoxin levels by 81% from an initial average of 53 ppb, while fumonisin levels in the same grain samples were reduced an average of 85% from an initial level of 17 ppm. Similar reductions in mycotoxin levels were observed after high‐speed sorting of A. flavus inoculated and naturally mold‐infested corn grown in Illinois. 相似文献
13.
E. San Martín‐Martínez M. R. Jaime‐Fonseca F. Martínez‐Bustos J. L. Martínez‐Montes 《Cereal Chemistry》2003,80(1):13-19
Using a continuous decorticating machine, white dent corn was efficiently separated, after brief steeping in water, into two fractions: the first (12.5%) consisting mainly of pericarp, germ, and tip cap (PGT); the second (87.5%) consisting of endosperm. Nixtamalization of the maize fractions in the presence of 0.6% (w/w) lime caused an increase in the hot‐paste viscosity at 90°C, while nixtamalization of PGT at lime inputs <0.6% (w/w) resulted in decreased viscosity. Three domains were found for the viscosity of nixtamalized endosperm at 90°C: lower concentrations of lime (< 0.15%, w/w) resulted in lower viscosity values; increased lime (0.15% – <0.3%, w/w) increased the viscosity values; and a lime concentration of 0.3% (w/w) resulted in a lower viscosity value. The response variables (water absorption index, water solubility index, initial viscosity, and viscosity at 90°C for nixtamalized PGT, and compression force and compression area of tortillas) indicated that the mathematical models fit the experimental data and the variance of the models was highly significant. Tortillas of good functional characteristics similar to tortillas produced by the traditional process were obtained when 5% nixtamalized fractions of PGT were blended with 95% nixtamalized endosperm. 相似文献
14.
为了有效克服果穗形状畸变和穗粒颜色差异对穗粒分割的影响,该文提出一种准确、鲁棒的玉米果穗穗粒分割方法。该方法利用果穗三维形状特征校正果穗径向畸变以最大程度恢复图像上果穗表面信息;采用分级阈值分割策略确定每颗穗粒最佳阈值范围,并利用穗粒几何特征实现穗粒初次筛分,消除穗粒间粘连效应;结合主成份分析和支持向量模型完成穗粒的二次筛分,生成果穗表面穗粒分布图。该方法整合了果穗径向畸变-分级阈值-穗粒多级筛分,实现果穗穗粒的精准分割,为玉米果穗自动化考种提供了基础方法。试验结果表明提出方法在穗粒分割准确性和鲁棒性上具有显著优势,平均计算效率达15 s/果穗。 相似文献
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Francisco Perdomo-Roldán Manuel A. Galindo-Reyes Heike Vibrans 《Genetic Resources and Crop Evolution》2009,56(3):353-362
This study explores the morphological variability and resource allocation of weedy, annual teosinte (Zea mays ssp. mexicana (Schrader) Iltis, Chalco race) from the Valley of Toluca, central Mexico, and compares it with data reported for maize. One
hundred mature and fertile teosinte plants were selected for variation in size and measured. The extremes found for fertile
plants were 0.12 and 3.5 m in height and 0.09 vs. 694 g in weight. Fruit were polymorphic, with significant correlation between
color and weight. Small plants invested slightly more biomass in the leaves and tall plants invested more in the stem. The
minimum mass necessary to produce fertile plants was much lower in teosinte than in maize. Very small teosinte plants formed
only female inflorescences, whereas maize produces a tassel. The harvest index was similar to landrace maize, and did not
decrease in taller plants, as teosinte can increase the reproductive sink. Toluca teosinte retains several important characteristics
of weeds: size variability, adaptation of fruit quantity to environmental conditions, and fruit polymorphism. 相似文献
16.
Ti Da Ge Fang Gong Sui San'an Nie Ning Bo Sun He'ai Xiao Cheng Li Tong 《Journal of plant nutrition》2013,36(12):1811-1818
Water is a key factor influencing the yield and quality of crops. Thus, a field simulative study was carried out from 2002 to 2003 in order to assess yield and nutritional composition changes in maize (Zea mays L.) grains at three different soil moisture levels: full-watered (FW), moderately stressed (MS), and severely stressed (SS). Our data indicated that SS treatment significantly increased nitrogen (N), calcium (Ca), magnesium (Mg), copper (Cu), and zinc (Zn) contents in maize grains by 11.9%, 27.8%, 11.1%, 18.4%, and 32.9%, respectively, when compared to FW. However, significant decreases (P < 0.05) in starch, phosphorus (P), and potassium (K) contents and yields in maize grains, about 27.9%, 16.5%, 16.7%, and 375.2%, respectively, were seen at SS treatment as compared to those in the FW treatment. In contrast, crude fat content had a different pattern in response to drought stress as compared to most nutritional compositions in maize grains. It generally followed the series MS > FW > SS. These results suggested that although some nutritional compositions in maize grains were positively affected by drought stress, the yields decreased significantly. 相似文献
17.
计算机视觉技术已经广泛应用于农业生产领域。对计算机视觉技术在玉米种子质量检验、玉米品种的识别、玉米粒形的检测、玉米田间杂草的识别等方面的应用做了介绍。 相似文献
18.
The relative effectiveness of dehulling, potassium hydroxide dipping (alkali concentrations 0.2, 0.5, and 1.0 %), and ethyl oleate spraying (aqueous emulsion 1%, v/v) to increase the rate of water absorption by dent and flint corn during steeping was compared with untreated corn samples. These pretreatments increased the water absorption rate of both hybrids when compared with the untreated control samples. To evaluate the observed increase, the diffusion coefficients of pretreated and untreated corn samples were estimated. Corn grains steeped in SO2 aqueous solution and variable lactic acid concentrations (0.2, 0.5, and 1.0%, v/v) were performed. Absorption rates for lactic acid concentrations were ≈0.5% higher than those steeped only in SO2 solution. This effect was more marked for dent than for flint corn. Corn samples pretreated with potassium hydroxide had lower starch yields than the control. However, the presence of lactic acid in steepwater increased the starch yield of dent and flint corn, particularly for the samples treated with alkaline solution. This procedure was particularly beneficial for flint corn. An effective release of the starch granules was achieved within 24 hr of steeping. 相似文献
19.
农业物料的冲击破碎特性对运输、排种和粉碎等机械设备的工作参数设定具有重要参考意义。该研究以玉米籽粒为研究对象，设计并搭建了单颗粒物料冲击破碎试验装置，开展了5种不同含水率（10.86%±0.13%，13.87%±0.18%，17.24%±0.08%、20.23%±0.19%和23.46%±0.23%）玉米籽粒的冲击破碎试验，并以籽粒破碎模式、临界速度和破碎程度表征籽粒的破碎特性。试验结果表明，玉米籽粒的破碎模式可分为未破碎、破裂和破碎3种形式，其中破裂形式包括整体破裂和局部破裂；以碎粒中大颗粒质量与玉米籽粒质量间的比值W界定玉米籽粒的破碎模式，并建立了不同含水率玉米籽粒的W值与冲击速度间的回归模型，模型的决定系数均大于0.92，确定了5种不同含水率（含水率由低到高）玉米籽粒的临界破裂速度分别为11.45、15.54、19.84、30.49和34.28 m/s，临界破碎速度分别为19.55、23.75、28.68、42.07和46.79 m/s，表明玉米籽粒的临界破裂速度和破碎速度均随含水率的增加而增加；采用响应曲面法建立了破碎颗粒平均粒径与冲击速度和含水率之间的回归模型，模型的决定系数为0.96，方差分析结果表明冲击速度、含水率及其交互作用对玉米籽粒的破碎程度影响极显著（P<0.01），且破碎程度随冲击速度的提高而增加，随含水率的提高而降低。该研究可为玉米籽粒处理设备的工作参数设定提供参考，并为农业物料颗粒的冲击破碎特性研究提供理论依据和试验方法参考。 相似文献
20.
The Sequential Extraction Process (SEP), a process that uses ethanol to fractionate corn into high‐value co‐products when producing fuel ethanol, was evaluated using high‐oil corn (HOC). Oil and protein recoveries, ethanol‐drying capability, and oil and protein properties were compared with those produced from normal soft dent corn (SDC) using SEP. Moisture adsorption capacities (≈24 g of water/kg of corn) and oil recoveries (>95%) were nearly identical for both corn types. However, oil yield from HOC (7.1 g of oil/100 g of corn) was 65% more than that of SDC (4.3 g of oil/100 g of corn). HOC crude oil was less red and contained lower free fatty acid and phosphatide contents than did SDC oil. HOC zein contained higher crude protein content (86% db) than did SDC zein (79% db). The freeze‐dried glutelin‐rich fractions (GRF) from both types of corn contained >90% (db) crude protein, which meet the criteria of protein isolates. SEP GRF protein isolates had >85% protein soluble in water at pH ≥ 7. Both GRF protein isolates from HOC and SDC were heat‐stable, had good emulsifying capacities, and produced highly stable emulsions. They also had substantial foaming capacities, but the foam from HOC GRF protein isolate was significantly more stable than the foam from SDC GRF protein isolate. SEP is a suitable process for recovering oil and protein products from HOC corn when producing fuel ethanol and, if competitively priced, HOC is a preferred feedstock to SDC because of higher yields and qualities of valuable co‐products when using HOC. 相似文献