Popping of amaranth grain (Amaranthus caudatus) and its effect on the functional,nutritional and sensory properties

The popping of amarunth grain (Amaranthus caudatus var INIAP‐Alegría) by hot air processing was studied. A household corn popper adapted to control heating and airflow was used. The effects of temperature, load, airflow and moisture on the popping capacity and on the functional properties, nutritional quality, crude protein content, lysine content and sensory texture of the poppei grain were investigate. The yield, expansion volume and density of popped grain showed that the optimal conditions for the popping process were 240 °C, 22 g load, 0.013 m³ s^?1 airflow and 12% grain moisture. The proportion of popped grain with butterfly shape was highest (p < 0.05) at 220 °C, 22 g load, 0.014 m³ s^?1 airflow and 14% grain moisture. The functional and physic‐chemical properties of popped grain obtained by various treatments showed completely gelatinised starch. The total, available and resistant starch contents were similar among the different treatments. The enzymatic degradation of starch was 65% within 5–15 min of incubation with α‐amylase. The crude protein content was almost 15% for all the treatments, while the total lysine content was 45.2–48.0 mg g^?1 protein. The in vitro availability of protein of popped grain obtained at 0.013 m³ s^?1 airflow and 14% grain moisture was above 84%. The highest available lysine value was found for popped grain obtained at 0.014 m³ s^?1 airflow, 18–22 g load and 12–14% grain moisture. However, six of the eight treatments had available lysine contents that varied between 41.2 and 47.4 mg g^?1 protein. Sensory analyses showed that the treatments with the highest popping capacity produced grains with high crunch and expansion capacities. © 2002 Society of Chemical Industry     

Evaluation of the effect of moisture content on cereal grains by digital image analysis

Physical appearance and kernel morphology significantly affect the grade of a harvested crop in addition to other factors such as test weight, percentage of foreign matter and constituent components. Moisture content of grain can potentially affect the physical appearance and kernel morphology. The objective of this study was to evaluate the effect of moisture content on the classification capability of colour, morphology and textural features of imaged grains. Colour images of individual kernels and bulk samples of three grain types, namely Canada Western Amber Durum (CWAD) wheat, Canada Western Red Spring (CWRS) wheat and barley were acquired using a machine vision system. The grain kernels were conditioned to 12%, 14%, 16%, 18% and 20% moisture contents before imaging. Previously developed algorithms were used to extract 123 colour, 56 textural features from bulk sample images and 123 colour, 56 textural, 51 morphological features from individual kernel images. The extracted features were analysed for the effect of moisture content. Statistical classifiers and a back propagation neural network model were used for classifying the grain bulk at different moisture contents. The colour and textural features of bulk grain images were affected by the moisture content more than that of the single kernel images.     

Geometric and Mechanical Properties of Mung Bean (Vigna Radiata L.) Grain: Effect of Moisture

In this research, selected geometric and mechanical properties of mung bean grain were evaluated as a function of moisture content. Five levels of moisture content ranging from 7.28 to 17.77% d.b. (dry basis) were used. The average length, width, thickness, arithmetic and geometric mean diameters, sphericity, thousand grain mass and angle of repose ranged from 5.145 to 6.199 mm, 3.760 to 4.474 mm, 3.537 to 4.223 mm, 4.147 to 4.965 mm, 4.090 to 4.893 mm, 0.795 to 0.789, 52.3 to 64.6 g, and 25.87 to 29.38° as the moisture content increased from 7.28 to 17.77% d.b., respectively. The bulk density was found to be decreased from 821.3 to 745.2 kg/m³, whereas the grain volume, true density, porosity, terminal velocity, and projected area were found to be increased from 27.88 to 47.33 mm³, 1230.0 to 1456.7 kg/m³, 30.43 to 46.57%, 4.86 to 5.29 m/s, and 17.48 to 19.26 mm², respectively. There is a 43% increase in surface area from grain moisture content of 7.28 to 17.77% d.b. The static coefficient of friction on various surfaces increased linearly with the increase in moisture content. The rubber as a surface for sliding offered the maximum friction followed by galvanised iron, medium density fibreboard, stainless steel, aluminium and glass sheet. As moisture content increased from 7.28 to 17.77%, the rupture forces values ranged from 67.39 to 39.44 N; 63.86 to 42.18 N, and 53.96 to 41.79 N for thickness (Z axis), length (Y-axis) and width (X-axis), respectively.     

Mycotoxins in cereal grain Part 12. Contamination with ochratoxin A and penicillic acid as indicator of improper storage of cereal grain

Formation of ochratoxin A and penicillic acid in wheat kernels at 6 moisture levels: 15, 18, 21, 24, 27 and 30% at 15 °C has been examined during 4 months of storage. The minimum time for formation of significant amount (0.5–1 mg/kg) of ochratoxin A and penicillic acid (6–8 mg/kg) in stored grain has been found for the various water contents as follows: 18%–16 weeks, 21%–6 weeks, 24% and more — 2 weeks. At 15% of moisture content formation of ochratoxin A and penicillic acid was not observed until 4 months of storage.     

Relationship of Sorghum kernel size to physiochemical,milling, pasting,and cooking properties

Effects of kernel size on grain sorghum [Sorghum bicolor (L.) Moench] quality were studied in an experiment designed to separate effects of kernel size from seedlot. The study utilized three sieve fractions of varying kernel diameter (>3.35, >2.80 and >2.36 mm) from six seedlots. Chemical composition, physical characteristics, milling characteristics, pasting properties, and cooking qualities were determined for each kernel size fraction. Large kernels lost less relative mass during 1 min of decortication, were higher in protein concentration, and lower in ash. Milling yields were higher from large kernels, and flour from large kernels had higher water absorbance, brighter white color, and larger particle size. Kernel size effects on Rapid Visco Analyzer (RVA) properties were not consistent. These results suggest that within the sorghum seedlots studied, an increase in kernel size is associated with an increase in sorghum quality as defined by the parameters measured in this study.     

双扩散传热传质模型及在横向谷冷通风中应用

本文首先建立了单颗粒小麦内部水分迁移模型,基于有限元的方法数值模拟了颗粒内部水分变化规律,通过回归数值模拟数据,得到了颗粒平均水分模型和平均水分变化的干燥(或吸湿)速率模型。在此基础上推导出了谷物颗粒堆积床双扩散传热传质模型,并采用有限元的方法数值模拟分析了就仓横向(水平)谷冷通风时仓储粮堆内部热湿耦合传递规律。通过比较数值模拟和实验测定数据,验证了所建立的模型的合理性。分析了横向谷冷通风时粮粒温度和水分以及粮粒周围空气温度的变化规律,探讨了横向谷冷通风时粮堆内部降温效果。     

Effect of micronisation and electromagnetic radiation on physical and mechanical properties of Canadian barley

The effect of micronisation (high‐intensity infrared heating) and microwave radiation of normal barley (NB), high‐amylose barley (HAB) and waxy barley (WB) on the physical and mechanical properties was studied. Samples were tempered to 42–45% moisture content and then subjected to infrared or microwave radiation to reduce the moisture content to approximately 10%. The grain surface temperature during radiation was maintained at 100 °C. The changes in physical and mechanical properties were compared with unprocessed samples. Thermal radiation increased slightly the volume of the kernels because of the diffusion of water vapour from inside to the outer surface. These changes resulted in a decrease in particle and bulk densities. Thermal radiation affected the Hunter colour values, as well. The mechanical properties including bio‐yield point, modulus of elasticity and breakage susceptibility were affected by micronisation and microwave heating.     

Natural occurrence of scirpentriol in cereals infected by Fusarium species.

Wheat, barley and oat grain samples naturally contaminated with Fusarium spp. were analysed for the presence of scirpentriol (STO). This toxin was detected in 1, 37 and 8% of 248 wheat, 32 barley and 99 oat grain samples, respectively, and the maximum concentration was 83 microg x kg(-1). Samples of wheat and oat grain with visible scab symptoms were also analysed, and STO (mean level 255 microg x kg(-1)) was detected only in oat samples infected with F. sporotrichioides and F. poae as the dominant species. We analysed 15 barley samples that were subdivided based on seed size into fractions of <2.5 and > 2.5 mm in diameter. The smaller kernels contained an average 94% of the STO in the samples (in kernel fraction > 2.5 mm 28 microg x kg(-1), <2.5 mm 297 microg x kg(-1)). In oats, STO levels were highest in the chaff, lower in the stalk's apical internode and lowest in the grain.     

Estimation of moisture in undried wheat and barley by near infrared reflectance

The potential of near infrared reflectance spectroscopy for estimating moisture in undried wheat and barley was investigated. Calibrations were developed for use with wholegrain (13–20% moisture) and coarsely-ground grain (13–26% moisture) for both grain types. The performance (accuracy and precision) during the 1983 harvest of the calibrations involving coarsely-ground grain (13–26% moisture) was superior to that of three moisture meters currently in commercial use in Ireland.     

Estimating mycotoxin contents of Fusarium-damaged winter wheat kernels

Winter wheat (Triticum aestivum L., cultivars Ritmo and Dekan) grain was sampled in Northern Germany between 2001 and 2006. Kernels damaged by fungi of the genus Fusarium were separated from sound grain by visual assessment. Samples containing 0%, 20%, 40%, 60%, 80% and 100% of Fusarium-damaged kernels were compiled and analyzed for the Fusarium type B trichothecenes deoxynivalenol (DON, 2001-2006), nivalenol (NIV, 2006), 3-acetyl-deoxynivalenol (3AcDON, 2006) and 15-acetyl-deoxynivalenol (15AcDON, 2006). The relationship between mycotoxin contents and the percentage of Fusarium-damaged kernels was calculated for each lot of grain. Apart from one exception, relationships between the percentage of Fusarium-damaged kernels and NIV, 3AcDON or 15AcDON were non-significant. In contrast, close relationships between the percentage of Fusarium-damaged kernels and the DON content were observed (r(2)=0.93-0.99). The y-axis intercepts were not significantly different from zero, but the DON content of the damaged kernels varied by a factor of 11.59 between years and by a factor of 1.87 between cultivars. Fusarium-damaged kernels contained between 0.21 and 2.39 microg DON kernel(-1). The overall average DON content of a Fusarium-damaged wheat kernel was 1.29 +/- 0.11 microg. The DON content of diseased kernels was affected by environment and wheat genotype but not by genotype x environment interaction. On average, Fusarium-damaged kernels contained 9.7-fold more DON than 15AcDON, 19.5-fold more DON than NIV, and 26.9-fold more DON than 3AcDON. 3AcDON and 15AcDON contents per wheat kernel were not significantly different between cultivars. On average, 4.27% of Fusarium-damaged kernels were sufficient to reach the 1.25 mg DON kg(-1) grain limit for unprocessed cereals in the EU. Given the low percentages of Fusarium-damaged kernels that are equivalent to current legal DON limits, grading accuracies >96% would be needed when using automatic grading systems for separating sound from damaged kernels.     

Studies on kolanut and cashew kernels: moisture adsorption isotherm,proximate composition,and functional properties

Kolanut (Cola nitida) and cashew (Anacardium occidentale) kernels were analysed and their moisture adsorption isotherms, proximate composition, and functional properties were compared. The dried powdered sample of kolanut contained 69% carbohydrate, 18% crude fat and 3.1% ash by weight, while the cashew sample had 51% crude fat, 36% crude protein, 0.3% ash and 3.4% carbohydrate. These differences significantly affected their relative water and oil absorption capacities, least gelation concentration, bulk density, and emulsion properties. However, both samples would retain nutritional integrity when stored in atmospheres with water activities of up to 0.68 for kolanut and 0.85 for cashew kernels. The Brunauer–Emmett–Teller (BET) and Henderson mathematical models described both isotherms with less than 2% mean relative deviation.     

Evaluation of Wheat Bran Obtained by Tangential Abrasive Dehulling Device

A tangential abrasive dehulling device (TADD) was used to evaluate debranning properties of wheat grain and obtain grain fractions enriched in antioxidants. Effect of grain moisture content and abrasion time on the chemical composition and antioxidant capacity of the fractions were examined. Whole wheat, bran from a quadrumat senior mill, and a commercial aleurone sample were used as references. Total phenolic content (TPC), oxygen radical absorbance capacity (ORAC) and 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging capacity of the TADD bran extracts were determined and compared to those of the reference materials and butylated hydroxytoluene (BHT). TADD bran fraction obtained at original grain moisture level, 11%, and short abrasion time, 1 min, had the highest ORAC value among the samples examined in this study. Only the sample obtained at 11% moisture level and 1 min abrasion time had similar ORAC, TPC, and DPPH values that are similar to those of the commercial aleurone despite the big difference in their starch content. The effect of grain moisture, abrasion time, and moisture?×?abrasion time interaction had significant effects on the chemical composition and antioxidant capacity of the fractions. This study demonstrated that TADD was very effective in producing wheat grain fractions with high antioxidant content.     

Fungal colonists of maize grain conditioned at constant temperatures and humidities

Fungal colonization of shelled maize (Pioneer 3320) harvested from a field near Furman, South Carolina, in 1992 was determined after 348 and 751 days of continuous storage at each of seven temperatures (10, 15, 20, 25, 30, 35, or 40°C) and four constant relative humidities, giving equilibrium grain moisture contents ranging from 9.4% to 17.5% m.c. in 28 grain conditioning environments. Twenty fungal species infected surface sterilized seeds and were recorded from these conditioned grain treatments, including species commonly found in preharvest maize [e.g. Acremonium zeae, Aspergillus flavus, Fusarium moniliforme (syn. F. verticillioides), Penicillium pinophilum (syn. P. funiculosum), etc.]. Eupenicillium cinnamopurpureum and Monascus ruber were recorded only from conditioned grain treatments. Eurotium chevalieri colonized 50–96% of the kernels from grain conditioning treatments with the highest moisture content for each incubation temperature. Grain samples with>33% E. chevalieri infection had a decreased occurrence of F. moniliforme and A. zeae, and no kernels from these samples germinated. No fungi colonized more than 50% of the kernels conditioned at 30–40°C and 9.4–14.2% m.c. The results of this study indicate that individual patterns of fungal colonization during grain conditioning were a function of the survival rates for preharvest fungal colonists and their potential replacement by E. chevalieri.     

烘干机内部谷物水分实时检测系统

目的:减少贮存时因水分含量高引起的谷物霉变.方法:通过在多地进行数据测量确定含水量与检测频率的函数模型,设计一套以STM32单片机为控制芯片的烘干机内部谷物水分实时监测系统.设计平行极板传感器来检测不同含水量谷物的电容变化值,经由硬件电路将电容值转换为频率值,经过单片机计算后可得到烘干机内部谷物实时水分含量,再利用RS485通讯协议传输至显示屏实时显示.结果:该系统在线监测误差在0.5%以内,上位机实时显示水分含量的延迟时间小于0.1s,完全满足工程应用要求.结论:通过实地安装测试,该系统工作效率高,不会对谷物造成二次伤害.     

Distribution of deoxynivalenol in barley kernels infected by Fusarium

Deoxynivalenol (DON) in concentration range 0.1 — 156.6 mg/kg, was found in 48 samples of barley kernels collected from heads with visible symptoms of head scab after inoculation in a field with Fusarium culmorum and Fusarium graminearum. Four fractions of the kernels were collected according to their size: >2.8 mm (I); ≤2.8 — 2.5 mm (II); >2.5 — 2.2 mm (III) and <2.2 mm (IV). In plants infected with Fusarium (when compared to the control) number of kernels in the fraction of the largest kernels (>2.8 mm) decreased from 38% to 18%, while in small kernels (fractions <2.5 — 2.2 mm and <2 .2 mm) numbers increased respectively from 16 to 22% and from 14 to 28%. Average level of DON concentration in these fractions was as follows: (I) 3.5 mg/kg — (4%); (II) 9.1 mg/kg — (16%); (III) 35.5 mg/kg — (29%) and (IV) 43.3 mg/kg — (51%). The highest DON accumulation was observed in fraction of small (<2.5 mm) kernels. The fraction contributed from 77% up to 94% of total DON content in kernels with low (<2 mg/kg) and high (>100 mg/ kg) contamination level, respectively. These results indicate that as well level of samples contamination with DON as human and animal health risk in consequence can be reduced by kernels selection (according their size) followed by rejection of the smallest kernels fraction.     

Strength and Frictional Properties of Popcorn Kernel as Affected by Moisture Content

Strength properties and dynamic coefficient of friction of popcorn kernels were evaluated as a function of moisture content in the range of 7.78–16.72 g/100 g dry solids. In order to determine strength properties of the kernels that are in terms of deformation at rupture point, rupture force, energy absorbed, hardness, and toughness of the popcorn kernels were quasi-statically loaded between two parallel plates. To determine frictional properties, friction tests were performed on aluminum, steel, and fiberglass surfaces. The values related to the strength properties, in general, decreased as the moisture content increased. On the other hand, the dynamic coefficient of friction of the popcorn kernels increased with increasing moisture content.     

Effects of moisture content and compression axis on mechanical properties of Shea kernel

Some mechanical properties of Shea kernel were investigated in this study. The kernels were divided into two categories sizes namely: small size kernel (SSK) and large size kernel (LSK) and the properties investigated were: rupture force, deformation at rupture and energy consumed at rupture. The tests were carried out at a deformation rate of 50 mm/min and four moisture content levels of 25.9%, 11.60%, 6.88%, 4.98% (db) for SSK and 11.19%, 6.21%, 5.78% and 2.77% (db) for LSK. The variations in these properties were observed considering the effects of moisture content and compression axes on them as the kernels were air-dried. Sample kernels were compressed along the orthogonal axes corresponding to major axes (length), intermediate axes (width) and minor axes (thickness) of Shea kernel. Some physical characteristics of Shea kernel such as dimensions, geometric mean diameter and mass were also evaluated. Results showed that generally, rupture force, deformation and energy at rupture decreased as moisture content decreased. The regression models that best fitted the relationships were polynomial functions of the second order. The highest and lowest forces for Shea kernel to rupture were those through the minor axis (thickness) and major axis (length) respectively. These properties are often required for the design of transportation, storage and grading/sorting machines and other post harvest machines for Shea kernel.     

Moisture Dependent Physical Properties of Dry Sweet Corn Kernels

Physical properties of sweet corn kernels have been evaluated as a function of kernel moisture content, varying from 9.12 to 17.06% (db). In the moisture range, kernel length, width, thickness, and geometric mean diameter increased linearly from 9.87 to11.09 mm, 7.41 to 9.25 mm, 3.25 to 4.37 mm, and 6.18 to 7.62 mm, respectively, with increase in moisture content from 9.12–17.06%. The sphericity index, kernel volume, kernel surface area, and thousand seed weight increased linearly from 62.6 to 68.8, 93.8 to 194.3 mm³, 120.1 to 182.9 mm², and 220 to 268 gr, respectively. Apparent density and bulk density decreased linearly from 1.315 to 1.232 g/cm³ and 0.765 to 0.698 g/cm³, respectively, while bulk porosity increased from 41.8 to 43.3%. The highest static coefficient of friction was found on the plywood surface. The static coefficient of friction increased from 0.680 to 0.891, 0.605 to 0.741, and 0.530 to 0.644 for plywood, galvanized iron, and aluminum surfaces, respectively. The angle of repose increased linearly from 30.2 to 35.2° with the increase of moisture content.     

PHYSICAL,CHEMICAL, and THERMAL CHARACTERIZATION of WHEAT FLOUR MILLING COPRODUCTS1,2

Hard red winter (HRW) and hard red spring (HRS) wheat milling coproducts (bran, germ, shorts, and red dog) from three commercial flour mills and the Kansas State University pilot mill were evaluated for differences in physical, chemical, and thermal properties. the ranges of bulk density for bran, germ, and red dog determined at three moisture levels were 146.5 to 205.2 kgm^?3, 269.2 to 400.6 kgm^?3, and 298.9 to 398.1 kgm^?3, respectively. the true density ranking order was: red dog >shorts = germ >bran, independently of the moisture level. Red dog had the smallest geometrical mean diameter with the highest variation (coefficient of variation of 23.8%). There was a significant (P < 0.05) difference among wheat blends and milling flows in the thickness of bran and germ at the same particle separation size. the image analysis study determined that the equivalent projected area diameter of bran at the same separation size was significantly (P < 0.05) larger than that of germ. the ratio between the equivalent projected area diameter and the particle thickness were within ranges of 15.7 to 37.6 for bran and 15.5 to 32.2 for germ particles. the chemical composition (ash, protein, lipids and fiber) ranges were determined for each coproduct. Ranges of thermal conductivity for bran, germ, shorts, and red dog were 0.049 to 0.074, 0.054 to 0.0907, 0.057 to 0.076, and 0.063 to 0.080 W(mK)^?1, respectively. Specific heat of coproducts, measured with a differential scanning calorimeter, exhibited a wider range [1.08–1.94 kJ(kgK)^?1] than that observed in whole wheat kernels and wheat flour. the variability observed among the samples was due to the different wheat sources and characteristic milling flows for the flour mills.     

Protein content of grains of different size fractions in malting barley

The negative relationship between grain size (percentage >2.5 mm) and protein content usually observed in barley grain samples is attributed to the presence of thin grains. The objective of this study was to determine whether, in grain samples from a given environment, thin grains had a different protein content than plump grains. Grain samples from field experiments were analysed for grain yield, size and protein content of the whole sample and of four size fractions within each sample. Grain yield ranged from 1.5 to 6.5 mg ha^?1 and grain protein (whole sample) ranged from 6.8 to 13.4 %. Most of the variation observed in protein content was explained by the ratio of nitrogen availability to grain yield. Within a grain sample, thin grains had more protein than plump grains (>2.5 mm) only when the protein content of the whole sample was high, that is, when the grain sample came from an environment with a high relative abundance of nitrogen. The fact that grain samples with low grain size tend to have high protein content is not due to the presence of a high proportion of thin grains, because thin grains do not always have more protein than plump grains. Copyright © 2014 The Institute of Brewing & Distilling