Detection of Sprouted and Midge‐Damaged Wheat Kernels Using Near‐Infrared Hyperspectral Imaging

Sprout damage which results in poor breadmaking quality due to enzymatic activity of α‐amylase is one of the important grading factors of wheat in Canada. Potential of near‐infrared (NIR) hyperspectral imaging was investigated to detect sprouting of wheat kernels. Artificially sprouted, midge‐damaged, and healthy wheat kernels were scanned using NIR hyperspectral imaging system in the range of 1000–1600 nm at 60 evenly distributed wavelengths. Multivariate image analysis (MVI) technique based on principal components analysis (PCA) was applied to reduce the dimensionality of the hyperspectral data. Three wavelengths 1101.7, 1132.2, and 1305.1 nm were identified as significant and used in analysis. Statistical discriminant classifiers (linear, quadratic, and Mahalanobis) were used to classify sprouted, midge‐damaged, and healthy wheat kernels. The discriminant classifiers gave maximum accuracy of 98.3 and 100% for classifying healthy and damaged kernels, respectively.     

Macromolecular and Micronutrient Profiles of Sprouted Chickpeas to Be Used for Integrating Cereal‐Based Food

Pulse flour may be used to improve nutritional traits of gluten and gluten‐free formulations in traditional food such as bread or pasta. However, owing to some intrinsic nutritional, textural, and sensory properties, the use of pulses as ingredients for production of enriched food remains limited. In this study, we investigated the modification in macromolecules and micronutrients in industrial‐scale flour from partially sprouted chickpeas to define its possible use as an ingredient in cereal‐based foods. Controlled sprouting resulted in significant decrease of antinutritional compounds (e.g., phytic acid and serine protease inhibitors) and in an increase of free minerals and vitamins. Sprouting also affected the overall structural organization of proteins (such as aggregate formation) and their thiol/disulfide balance, and it promoted release of peptides. All of these had a positive effect on dough mixing properties, in particular for dough development. Formulations with enrichment in sprouted chickpea flour (wheat/chickpea ratio = 100:20) were tested also as for their dough leavening properties, which improved with respect to flour from nonsprouted chickpeas. Taking into account the modifications induced by partial sprouting on an industrial scale, we can conclude that sprouted chickpea flour represents an interesting ingredient for production of enriched cereal‐based food with better nutritional and rheological characteristics.     

Defining the Overall Quality of Cowpea‐Enriched Rice‐Based Breakfast Cereals

The development of innovative legume‐enriched rice products is a promising way to exploit rice varieties with a low sensory grade. In this work, a multidisciplinary approach was applied to the characterization of extruded breakfast cereals prepared from African‐grown Oryza glaberrima (cv. Viwonor) or Oryza sativa (cv. Jasmine 85) enriched with 30% cowpea flour, obtained from sprouted or nonsprouted cowpea. Regardless of the rice species, addition of sprouted cowpea flour conferred a peculiar volatiles profile, rich in sour, bitter, and astringent taste. Protein structural indices provided molecular insights about the macroscopic differences among samples. Extruded products from O. glaberrima were characterized by lower expansion rates with respect to those obtained from O. sativa , regardless of the type of cowpea flour. Sprouting time had a positive influence on the hardness of extruded glaberrima‐based products, facilitating formation of a more compact matrix, but it did not influence sativa‐ based products. Therefore, the breakdown of protein during sprouting appeared fundamental for the incorporation of legume proteins in more compact matrices, such as the one from sativa rice. In the glaberrima‐based products, addition of sprouted cowpea resulted in further loosening of the structure, and this was more evident at increased sprouting times.     

Considerations regarding the use of hyperspectral imaging data in classifications of food products, exemplified by analysis of maize kernels

Development of robust analytical procedures is critical when using hyperspectral imaging technology in food technology and agriculture. This study used near-isogenic inbred corn lines to address two basic questions: (1) To what extent is classification accuracy increased by grinding maize kernels? (2) Can the classification accuracy of two near-isogenic inbred lines be increased by using a spectral filter to classify only certain hyperspectral profiles from each image cube? Whole kernels and ground kernels in two particle intervals, 0.250-0.354 mm (size 1) and 0.354-0.841 mm (size 2), were examined. Spectral profiles acquired from ground kernels had higher spectral repeatability than data collected from whole kernels. The classification error of discriminant functions from whole kernels was >3 times lower than that of size 1 ground particles. Applying a spectral filter to input data had negligible effect on classifications of hyperspectral profiles from whole kernels and size 2 ground particles, but for size 1 ground particles a considerable increase in accuracy was observed. Independent validation confirmed that distinction between wild type and mutant inbred maize lines could be conducted with >80% accuracy after the proposed spectral filter had been applied to hyperspectral profiles of size 1 ground particles. A combination of discriminant analysis and regression analysis could be used to accurately predict mixture ratios of the two inbred lines. The use of spectral filtering to increase the level of spectral repeatability and the use of hyperspectral imaging technology in large-scale commercial operations are discussed.     

Description of a Micromill with Instrumentation for Measuring Grinding Characteristics of Wheat Grain

A new method for characterizing the grinding characteristics of wheat grain is described. A micromill was designed for this purpose and equipped with on‐line torque transducers to obtain accurate measurements of mechanical energy consumption during milling. This micromill can be used for testing the milling performance of small quantities of grain (100 g). It can distinguish between different types of wheat grain (soft wheat, hard wheat, durum wheat) on the basis of total specific energy during milling. Wheat characterization can be enhanced by taking particle sizes of the milled products into account. A milling index based on energy consumption and particle size reduction was developed to characterize wheat behavior during milling. This index had a high discriminatory potential, ranging from 100 kJ/kg for soft wheat flour to 600 kJ/kg for durum wheat flour. This micromill directly measures the grinding resistance of wheat kernels as a function of both the kernel hardness and vitreousness, contrary to standard kernel hardness measurements obtained by particle size index and near‐infrared reflectance analysis techniques that only reflect the fracture mode (fine particle reduction potential).     

基于准静态压缩方法的玉米粒破碎试验

为减少粮食因破碎而导致的损耗浪费,探索玉米颗粒的抗破碎能力,该研究利用准静态压缩试验共获得了920组玉米粒的力学数据,并通过韦伯分布拟合对玉米粒破碎力进行了分析。试验对比压缩方位及压缩速率对玉米粒破碎力的影响,确定准静态压缩的试验条件,在此基础上探索玉米含水率、粒径、轴比对玉米粒破碎性质的影响。结果表明：沿玉米厚度方向压缩可获得玉米粒的最大破碎力;压缩速率小于0.10 s^-1时,压缩速率对玉米粒破碎力分布无影响。另外,玉米粒的含水率、粒径、轴比均影响其破碎力分布。含水率14.72%的玉米粒破碎力分布更为集中;小粒径玉米粒更容易破碎,粒径小于7 mm时玉米粒破碎率达100%;玉米粒破碎率和破碎力均与轴比呈反比,表明饱满圆润的玉米颗粒更容易发生破碎。该试验为玉米在储运、加工过程中的降碎降损提供了可靠的数据支撑。     

Near‐Infrared Spectroscopic Evaluation of Single‐Kernel Deoxynivalenol Accumulation and Fusarium Head Blight Resistance Components in Wheat

Fusarium head blight (FHB) symptoms, single‐kernel deoxynivalenol (DON) levels, and distribution of DON levels among kernels in response to artificial FHB inoculation were investigated in three selected wheat cultivars that had different reported levels of FHB resistance. DON levels were estimated with near‐infrared spectroscopy. The percentages of DON‐containing spikelets per spike of 15.2, 49.7, and 89.1% were significantly different among point‐inoculated spikes of Everest, Karl 92, and Overley, respectively. The percentage of visually Fusarium‐damaged kernels in point‐inoculated Karl 92 and Overley spikes was significantly higher than for Everest. However, the DON‐containing spikelets per spike and visually Fusarium‐damaged kernels values for spray‐inoculated spikes were not significantly different among the three cultivars. In spray‐inoculated spikes, DON levels in kernels ranged from 0 to 291.3 ppm, whereas the variation of DON levels in spikelet positions was random. In contrast, DON levels in spikelets below the inoculated spikelet in point‐inoculated spikes showed marked differences among the three cultivars. Overley had the highest DON accumulation in kernels. This near‐infrared spectroscopy method may be used as a novel way to evaluate wheat cultivars for FHB resistance to toxin accumulation. Other resistance components such as resistance to pathogen infection and resistance to pathogen spread may also be evaluated.     

Methods to Estimate Aggregate Protected Soil Organic Carbon, 2: Does the Grinding of the Plant Residues Affect the Estimations of the Aggregate Protected Soil Organic Carbon?

A method to estimate the amount of soil organic carbon (SOC) physically protected within macroaggregates (>200 μm) consists of crushing soil samples and measuring the following SOC mineralization increase. This study investigated the effect of grinding the plant residues during soil crushing on the calculated amount of the protected SOC on two tropical soils (Arenosol and Ferralsol). Incubations of crushed and uncrushed soil samples amended with ground or unground plant residues were conducted. Our results showed that soil crushing increased SOC mineralization and that the presence of plant residues enhanced soil respiration also. The plant residues of the two soils had different decomposition rates, but grinding plant residues did not increase the amounts of cumulative carbon (C) mineralized after the 28 days of the experiment. We propose that the extra C mineralized after soil crushing is due to the breakdown of the soil structure and not to the grinding of plant residues.     

Aflatoxin variation among corn samples with varying ratios of Aspergillus flavus-inoculated/noninoculated kernels.

Aflatoxin levels and physical properties of corn kernels inoculated with Aspergillus flavus during development and noninoculated kernels were compared in samples with various proportions of the 2 kernel types. The relationship between mean toxin levels and associated standard deviations of 5 samples demonstrated a linear association from the lowest toxin in noninoculated corn through a mixture of 60% inoculated/40% noninoculated. However, at the highest toxin level in the 100% inoculated material, a reduction in sample variation was observed. Examination of individual kernal weights showed that inoculated kernels were distinctly lighter than noninoculated seed. A uniform grinding procedure of the samples yielded heterogeneous particle sizes based on the starting corn. The large particle fraction (greater than 500 micrometers) decreased from 100% noninoculated kernels through the mixtures to the 100% inoculated seed; particles below 150 micrometers were most abundant in the ground samples from inoculated kernels. In addition, the density of particles within a size category varied; lower densities were observed in samples obtained from A. flavus-inoculated kernels.     

Determining Vitreous Subclasses of Hard Red Spring Wheat Using Visible/Near‐Infrared Spectroscopy

The percentage of dark hard vitreous (DHV) kernels in hard red spring wheat is an important grading factor that is associated with protein content, kernel hardness, milling properties, and baking quality. The current visual method of determining DHV and non‐DHV (NDHV) wheat kernels is time‐consuming, tedious, and subject to large errors. The objective of this research was to classify DHV and NDHV wheat kernels, including kernels that were checked, cracked, sprouted, or bleached using visible/near‐infrared (Vis/NIR) spectroscopy. Spectra from single DHV and NDHV kernels were collected using a diode‐array NIR spectrometer. The dorsal and crease sides of the kernels were viewed. Three wavelength regions, 500–750 nm, 750–1,700 nm, and 500–1700 nm were compared. Spectra were analyzed by using partial least squares (PLS) regression. Results suggest that the major contributors to classifying DHV and NDHV kernels are light scattering, protein content, kernel hardness, starch content, and kernel color effects on the absorption spectrum. Bleached kernels were the most difficult to classify because of high lightness values. The sample set with bleached kernels yielded lower classification accuracies of 91.1–97.1% compared with 97.5–100% for the sample set without bleached kernels. More than 75% of misclassified kernels were bleached. For sample sets without bleached kernels, the classification models that included the dorsal side gave the highest classification accuracies (99.6–100%) for the testing sample set. Wavelengths in both the Vis/NIR regions or the NIR region alone yielded better classification accuracies than those in the visible region only.     

饲料原料粉体流动特性预测模型

为了研究不同贮藏期大豆分离蛋白（soy protein isolate,SPI）对千页豆腐品质的影响,该文首先研究了贮藏期对大豆分离蛋白结构的影响,进而探讨贮藏期对大豆蛋白制备千页豆腐的品质的影响。对不同贮藏期的大豆蛋白分别采用了凝胶质构特性、感官评价、羰基含量、大豆蛋白亚基以及巯基的测定,并采用拉曼光谱对大豆蛋白二级结构、二硫键构型以及侧链结构进行了分析,同时采用扫描电镜观察千页豆腐的微结构。结果表明：随着贮藏期的延长,千页豆腐的感官评价变差,由88分降低至44分;其凝胶网络结构逐渐疏松;大豆蛋白羰基含量逐渐上升;巯基含量逐渐下降;二级结构含量改变;凝胶硬度呈下降趋势,硬度值低于234 g时,将无法达到千页豆腐的质量要求。这表明在贮藏期内SPI发生了氧化,导致大豆蛋白质结构发生改变,使其凝胶性质下降。     

High‐Speed NIR Segregation of High‐ and Low‐Protein Single Wheat Seeds

Wheat breeders need a nondestructive method to rapidly sort high‐ or low‐protein single kernels from samples for their breeding programs. For this reason, a commercial color sorter equipped with near‐infrared filters was evaluated for its potential to sort high‐ and low‐protein single wheat kernels. Hard red winter and hard white wheat cultivars with protein content >12.5% (classed as high‐protein, 12% moisture basis) or < 11.5% (classed as low‐protein) were blended in proportions of 50:50 and 95:5 (or 5:95) mass. These wheat blends were sorted using five passes that removed 10% of the mass for each pass. The bulk protein content of accepted kernels (accepts) and rejected kernels (rejects) were measured for each pass. For 50:50 blends, the protein in the first‐pass rejects changed as much as 1%. For the accepts, each pass changed the protein content of accepts by ≈0.1%, depending on wheat blends. At most, two re‐sorts of accepts would be required to move 95:5 blends in the direction of the dominant protein content. The 95:5 and 50:50 blends approximate the low‐ and high‐protein mixture range of early generation wheat populations, and thus the sorter has potential to aid breeders in purifying samples for developing high‐ or low‐protein wheat. Results indicate that sorting was partly driven by color and vitreousness differences between high‐ and low‐protein fractions. Development of a new background specific for high‐ or low‐protein and fabrication of better optical filters for protein might help improve the sorter performance.     

辐照协同甲酸分离油茶壳中纤维素、木质素和木糖的工艺研究

为了提高油菜壳木质纤维素分离效率,本试验以油茶壳为原料,研究不同辐照剂量(0、200、400、600、800 kGy)处理后其粉碎能耗、粒度分布和化学组分的变化,同时开展辐照协同甲酸分离油茶壳木质纤维素的工艺研究。结果表明,辐照处理后油茶壳粉碎能耗降低,粉碎后细颗粒样品所占比例增加,经400 kGy剂量辐照处理的油茶壳粉碎能耗比对照节约43.59%,800 kGy剂量辐照处理的油茶壳粉碎后粒径<0.075 mm的颗粒占比达到41.38%。辐照处理后油茶壳木质纤维素发生降解,水溶性组分、水溶性单糖、聚糖含量均增加。辐照协同甲酸分离油茶壳纤维素、木质素和木糖的最佳工艺为:辐照剂量400 kGy,反应温度100℃,反应时间3 h,在此条件下分离获得的油茶壳纤维素、木质素、木糖的提取率分别为89.94%、47.74%和96.37%,纤维素和木质素纯度分别为45.05%和91.92%。本研究结果对油茶壳木质纤维素全组分的高效分离和应用具有重要意义。     

Effects of Soil Sample Grinding Intensity on Carbon Determination by High‐Temperature Combustion

Abstract

Recently, many studies related to carbon (C) sequestration by soils have been reported. However, little information has been reported related to the need for and effects of grinding soils on C analysis by high‐temperature combustion. We studied the effects of grinding five glacially derived soils of varying textural composition and organic matter content to 2‐mm, 1‐mm, 0.5‐mm, 0.25‐mm, and 0.15‐mm particle sizes on the measurement of total, inorganic, and organic C content using a high‐temperature combustion technique. Medium‐textured soils showed significantly higher total and organic C values for the 2‐, 1‐, and 0.5‐mm particle sizes than for the 0.25‐ and 0.15‐mm particle sizes compared to soils that were high in sand or clay. Grinding did not appear to affect inorganic C values. Grinding the soils to 0.15 mm, in all cases, greatly reduced the variability of C values by as much as two‐ to six‐fold when compared to 2‐mm soils. We recommend that soils be ground to pass a 0.15‐mm (100‐mesh) screen prior to C analysis by high‐temperature combustion.     

Evaluation of a Near‐Infrared Reflectance Spectrometer as a Granulation Sensor for First‐Break Ground Wheat: Studies with Hard Red Winter Wheats

A single wheat class or blended wheats from two wheat classes are usually milled in a flour mill. A near‐infrared (NIR) reflectance spectrometer, previously evaluated as granulation sensor for first‐break ground wheat from six wheat classes, was evaluated for a single wheat class, hard red winter (HRW) wheat, using offline methods. The HRW wheats represented seven cultivars ground by an experimental roller mill at five roll gap settings (0.38, 0.51, 0.63, 0.75, and 0.88 mm) which yielded 35 ground wheat samples each for the calibration and validation sets. Granulation models based on partial least squares regression were developed with cumulative mass of size fractions as a reference value. Combinations of four data pretreatments (log 1/R, baseline correction, unit area normalization, and derivatives) and subregions of the 400–1,700 nm wavelength range were evaluated. Models that used pathlength correction (unit area normalization) predicted well each of the four size fractions of first‐break ground wheat. The best model, unit area normalization and first derivative, predicted all the validation spectra with standard errors of performance of 3.80, 1.29, 0.43, and 0.68 for the >1041, >375, >240, and >136 μm size fractions, respectively. Ground HRW wheats have narrower particle size distribution and better sieving properties than ground wheat from six wheat classes. Thus, HRW wheat granulation models performed better than the previously reported models for six wheat classes.     

Influence of soil particle size and grinding on bray‐2 extractable phosphorus

Abstract

The influence of soil particle size and soil fine grinding on Bray‐2 extractable phosphorus (Bray‐2P) was studied. Air‐dried and 2‐mm mesh‐sieved soil was separated into six particle size classes: <0.075, 0.075–0.106, 0.106–0.25, 0.25–0.425, 0.425–0.85, and 0.85–2 mm. The lowest amounts of Bray‐2P were found in the 0.425–0.85 and 0.85–2 mm fractions and the highest in <0.075 mm fraction. When ground for 3 min, the amount of Bray‐2P increased in the fractions larger than 0.25 mm, whereas it decreased in the fractions smaller than 0.25 mm. In the large fraction (0.425–0.85 mm), grinding for 1 to 3 min led to an increase in the amount of Bray‐2P, but grinding for 9 to 18 min caused a decrease. In contrast, in the small fraction (<0.075 mm), the amount of Bray‐2P decreased by grinding for 1 min. The large and small fractions that were ground absorbed P in proportion to the grinding time during the extraction‐filtration period.     

新型锤片式饲料粉碎机分离流道内物料运动规律

基于锤片式饲料粉碎机工作状况,研究物料颗粒在气固两相流中运动轨迹的数学模型,得到物料颗粒沿坐标轴方向上的运动微分方程和位移方程;并使用 MATLAB 对该数学模型进行了数值模拟,得到了物料颗粒理论运动轨迹,对模拟结果按入口固相颗粒速度大于、等于、小于气相速度3种情况进行研究;使用高速摄像机对分离流道内部分颗粒进行跟踪拍摄,并取粒径2 mm目标颗粒和粒径8 mm完整颗粒,对2种物料颗粒理论模型运动轨迹与真实运动轨迹进行了比较,验证了数学模型的合理性.对进一步研究宏观物料运动、颗粒分布及分离装置结构等提供了参考.     

Detecting and Segregating Black Tip‐Damaged Wheat Kernels Using Visible and Near‐Infrared Spectroscopy

Detection of individual wheat kernels with black tip symptom (BTS) and black tip damage (BTD) was demonstrated with near‐infrared reflectance spectroscopy (NIRS) and silicon light‐emitting‐diode (LED) based instruments. The two instruments tested, a single‐kernel NIRS instrument (SKNIRS) and a silicon LED‐based single‐kernel high‐speed sorter (SiLED‐SKS) were both developed by the Stored Product Insect and Engineering Research Unit, Center for Grain and Animal Health Research, USDA Agricultural Research Service. BTD was classified into four levels for the study ranging from sound, symptomatic (BTS) at two levels, and damaged (BTD). Discriminant analysis models for the SKNIRS instrument could distinguish sound undamaged kernels well, correctly classifying kernels 80% of the time. Damaged kernels were classified with 67% accuracy and symptomatic kernels at about 44%. Higher classification accuracy (81–87%) was obtained by creating only two groupings: 1) combined sound and lightly symptomatic kernels and 2) combined heavily symptomatic and damaged kernels. A linear regression model was developed from the SiLED‐SKS sorted fractions to predict the percentage of combined BTS and BTD kernels in a sample. The model had an R² of 0.64 and a standard error of prediction of 7.4%, showing it had some measurement ability for BTS and BTD. The SiLED‐SKS correctly classified and sorted out 90% of BTD and 66% of BTS for all 28 samples after three passes through the sorter. These instruments can serve as important tools for plant breeders and grading facilities of the wheat industry that require timely and objective determination and sorting of different levels of black tip present in wheat samples.     

Selecting and Sorting Waxy Wheat Kernels Using Near‐Infrared Spectroscopy

An automated single kernel near‐infrared (NIR) sorting system was used to separate single wheat (Triticum aestivum L.) kernels with amylose‐free (waxy) starch from reduced‐amylose (partial waxy) or wild‐type wheat kernels. Waxy kernels of hexaploid wheat are null for the granule‐bound starch synthase alleles at all three Wx gene loci; partial waxy kernels have at least one null and one functional allele. Wild‐type kernels have three functional alleles. Our results demonstrate that automated single kernel NIR technology can be used to select waxy kernels from segregating breeding lines or to purify advanced breeding lines for the low‐amylose kernel trait. Calibrations based on either amylose content or the waxy trait performed similarly. Also, a calibration developed using the amylose content of waxy, partial waxy, and wild‐type durum (T. turgidum L. var durum) wheat enabled adequate sorting for hard red winter and hard red spring wheat with no modifications. Regression coefficients indicated that absorption by starch in the NIR region contributed to the classification models. Single kernel NIR technology offers significant benefits to breeding programs that are developing wheat with amylose‐free starches.     

Effects of Roll Gap,Kernel Shape,and Moisture on Wheat Breakage Modeled Using the Double Normalized Kumaraswamy Breakage Function

Flour milling separates endosperm from bran through repeated roller milling and sifting, in which the size distribution of particles produced by the initial breakage of the wheat kernels critically affects the process. The double normalized Kumaraswamy breakage function (DNKBF), previously developed to describe wheat breakage during roller milling, was extended to refine the modeling of the effect of roll gap on breakage. The DNKBF describes two populations of particles arising from roller milling of wheat, a narrow peak of mid‐sized particles and a wider distribution of both small and very large particles. A new dataset was obtained from milling a set of wheat samples bred to give a range of shapes by cross‐breeding a conventional wheat, Cappelle, with an almost spherical wheat, Triticum sphaerococcum. A residual analysis showed a statistically significant effect of kernel shape on breakage using this new dataset. This analysis supports earlier suggestions that more elongated kernels break to give slightly larger particles than more spherical kernels of equivalent hardness, because of the relatively greater bran content of elongated kernels. The extended DNKBF was also used to model effects of moisture content, showing a distinct disjunction at around 16% moisture that aligns with commercial practice for wheat milling.