Nutritional evaluation of some commercial wheat varieties grown in Pakistan

The nutritive value of some commercial wheat varieties grown in Pakistan was measured chemically, including amino acid analysis, and biologically in N-balance experiments with growing rats. The protein content ranged from 13.2% in Punjab-83 to 16% in Barani-83. Lysine per 100g protein varied between 2.46 and 2.75%. The available carbohydrate ranged from 67.3 to 74.7%. Iron content was highest in Sonalika while the concentration of zinc and manganese was highest in Sarhad-82. The protein digestibility (TD), biological value (BV) and net protein utilisation (NPU) varied between 92–95%, 56–68% and 53–65% respectively. Level of wheat protein was negatively correlated with available carbohydrate (r=–0.93), lysine per unit protein (r=–0.67) and BV (r=–0.76). The lysine content (g/16gN) of commercial wheat varieties showed a positive correlation (r=+0.95) with the BV. The protein quality was lowered in varieties having higher content of protein.     

固相萃取-GC/LC-MS/MS测定茶叶中79种农药残留

建立了一套以一次固相萃取前处理方法,运用气相色谱-串联质谱（GC-MS/MS）和液相色谱-串联质谱（LC-MS/MS）两种检测技术,测定茶叶中79种农药残留的可靠、快速、高通量检测方法。该方法用20βmL乙腈一次均质提取,分取提取液10βmL,用乙腈+甲苯（3∶1）20βmL洗脱过Carbon/NH₂小柱净化,用5βmL乙腈定容混匀,于GC-MS/MS和LC-MS/MS同时检测。结果表明,79种农药在0.01~0.40βmg·L^-1范围内线性良好,相关系数（R²）在0.995以上;高、低、中3种水平加标回收率在67.3%~130.8%内;相对标准偏差（RSD）在15%内;98.7%的农药定量限（LOQ）≤0.01βmg·kg^-1;使用多种类茶叶实际检测,结果均合格。因此,该方法能同时检测含有机磷、有机氯、拟除虫菊酯类、氨基甲酸酯类和有机杂环类5大类农药,更有利于大批量茶叶样品的多农残检测。     

基于点评估方法的两广地区番木瓜中农药残留膳食暴露风险研究

为评估两广地区番木瓜中主要农药的残留情况及其产生的风险,采集了广东、广西地区40个生产基地的番木瓜样品进行测试分析,研究其生产过程中使用的杀虫剂、杀菌剂、杀螨剂和植物生长调节剂等各种农药残留情况,并对我国不同人群的膳食暴露风险进行了评估。结果显示,40批次番木瓜中检出农药残留32批次;在检出的32份番木瓜样品中,检出率超过10%的有咪鲜胺、吡虫啉、多菌灵、啶虫脒和苯醚甲环唑5种农药,检出率分别为51.1%、21.5%、13.3%、11.1%、10.9%。采用点评估方法,选择检出率在10%以上的咪鲜胺、吡虫啉、多菌灵、啶虫脒和苯醚甲环唑,进行农药残留慢性膳食摄入风险（%ADI）评估、急性膳食摄入风险（%ARfD）评估,并进行不同消费人群暴露点评估。结果显示：检出的5种农药%ADI均低于100.00%,为0.00023%~0.0059%;%ARfD远低于100%,为0.50%~28.3%,5种农药的急性和慢性摄入风险均为儿童高于成年人,绝大多数女性的摄入风险高于男性;5种农药急性摄入风险均高于慢性摄入风险,风险水平由高到低为咪鲜胺>啶虫脒>苯醚甲环唑>多菌灵>吡虫啉,但点评估结果均远低于100%,说明通过食用番木瓜摄入的农药残留极其微量,不会对人体产生急性或慢性风险。     

黔东南州茶叶农药残留膳食摄入风险评估

为了解黔东南州茶叶质量安全情况,本研究对黔东南州111份茶叶中的63种农药残留进行了检测分析,并按照膳食暴露评估和英国FSA（Food Standards Agency,英国食品标准局）风险排序体系对茶叶中检出农药进行风险分析。结果显示,茶叶样品的农药检出率为54.05%,检出农药22种,单项农药检出率为0.90%~31.53%。按照食品中农药最大残留限量（GB 2763—2016）判定,合格率97.30%;按照欧盟标准限量判定,合格率87.39%。根据膳食评估公式计算,所检出农药的慢性摄入风险（%ADI）为0.0037%~1.1780%,急性摄入风险（%ARfD）为0.03%~41.42%,表明黔东南州茶叶的慢性摄入风险和急性摄入风险都可接受。农药风险排序得出,农药在低、中和高风险水平的比例分别为45.45%、31.82%和22.73%,其中风险最高的农药是克百威。因此,黔东南州茶叶农药残留风险均在可接受范围,茶叶质量安全情况良好。     

Cloning, expression and characterization of novel avenin-like genes in wheat and related species

B-Type avenin-like genes and proteins were characterized in 23 species of Triticeae. Southern blot analysis showed that the avenin-like genes belong to a multigene family. RT-PCR showed expression only in developing endosperms of wheat and related species, between 3 and 22 DPA (days post anthesis) with a peak between 11 and 15 DPA in wheat. The encoded proteins are cysteine-rich, containing 18–19 cysteine residues. An avenin-like protein from wheat was expressed in Escherichia coli, purified and used to raise polyclonal antibodies. These antibodies were used to detect b-type avenin-like proteins in endosperms of wheat and related species by western blotting.     

Sensitivity of yield and grain nitrogen concentration of wheat, lupin and pea to source reduction during grain filling. A comparative survey under high yielding conditions

Several studies have been conducted to evaluate the response of crops, especially temperate cereals, to different source–sink ratios during grain filling. However, there is much less information about temperate legumes and even less work comparing the two. The objective of this study was to evaluate the response of both grain yield and grain nitrogen concentration of wheat (Triticum aestivum L.), narrow-leafed lupin (Lupinus angustifolius L.) and pea (Pisum sativum L.) to similar source reduction during grain filling. Two field experiments were conducted in a high yielding environment of Southern Chile. In experiment 1 wheat and narrow-leafed lupin were grown for two consecutive years. Experiment 2 evaluated wheat and pea on two sowing dates. In both experiments a reduction in the source–sink ratio was imposed by using black nets that intercepted 90% of the incident solar radiation from the commencement of the linear dry matter accumulation to physiological maturity. Grain yield was differentially (p < 0.01) decreased by the source reduction in lupin (98%), wheat (63%) and pea (26%). Given that these experiments were carried out in a high yielding environment, the higher response of wheat relative to previous studies supports the hypothesis that the higher the yield potential, the higher the source sensitivity of this crops during the grain filling period. On the other hand, source reduction positively affected (p < 0.05) grain nitrogen concentration in wheat (66%) and pea (18%) but negatively affected lupin (40%). The higher sensitivity of grain yield compared to that of grain nitrogen yield was the cause of the positive effect of the lower source–sink ratio recorded in wheat and pea. In contrast, source shortage in lupin decreased grain nitrogen concentration probably as result of the quick response of grain growth to source limitation. The contrasting sensitivities of lupin, wheat and pea to source reduction during grain filling prevent us to see grain yield and quality response of these crops as separate groups, i.e. temperate cereals vs. temperate legumes.     

基质固相分散萃取-高效液相色谱串联质谱法（HPLC-MS-MS）同时测定茶叶中11种农药的残留量

建立了茶叶中3类11种农药的分散固相萃取–高效液相色谱串联质谱（HPLC-MS-MS）的检测方法。茶叶样品以乙腈–乙酸（体积比99:1）提取,以PSA为净化剂基质固相分散萃取,然后通过C₁₈色谱柱,以甲醇/水（含甲酸铵）溶液进行梯度洗脱,采用电离喷雾电离方式（ESI+）,通过多反应监测（MRM）定量。结果表明：11种农药的分析时间约为20 min,在0~500 ng·mL^-1范围内线性相关,相关系数大于0.9995,方法检测限为0.1~1.7 μg·kg^-1。测定了茶叶样品中11种农药的残留量,加标回收率为62.4%~114.8%（添加水平分别为10~400 μg·kg^-1）,相对标准偏差（RSD）为3.28%~19.34%。选取了5个不同类型的茶叶样品,检测其中11种农药的残留量,检出结果差异较大。其中绿茶中11种农药的检出量为1.7~339.4 μg·kg^-1,加标回收率为86.1%~104.1%,相对标准偏差（RSD）均小于20%（n=6）。本方法准确、灵敏、简单、快速、安全,能满足茶叶样品中多种农药残留分析的要求。     

Comparison of color techniques to measure the color of parboiled rice

A combination of digital camera, computer and graphic software can provide a less expensive and more versatile technique to determine the surface color of parboiled rice compared to instrumental color measurement. The instrument was used to measure rice powder and whole rice. Pearson correlation coefficients and sample paired t-test on total color difference (ΔE), L and b values were calculated. The value of ΔE of samples from the instrumental technique was 0.69–4.61 (powder), 4.7–10.2 (whole rice) with a coefficient of variance (CV) ranging from 3.5 to 25.3% and from 15.4 to 46.6%. Meanwhile, the digital image technique gave a ΔE value ranging from 4.2 to 13.77 with a CV from 6.3 to 21.2%, respectively. A highly significant correlation (R² = 0.7451, R² = 0.8074, R² = 0.7518,) was obtained for ΔE between instrumental (powder and whole rice), Vision Builder and instrumental (powder), and instrumental (whole rice) and Vision Builder. The chromatic b value of instrumental for powder had a significant correlation with the Vision Builder data (R² = 0.7741). The results suggest that although the digital image provided the surface color of parboiled rice, it was less accurate than the instrumental for powder. Therefore results from the digital image should be interpreted with caution.     

Productivity and resource use of direct-(drum)-seeded and transplanted rice in puddled soils in rice–rice and rice–wheat ecosystems

Conventional tilled transplanting, a widely practiced method of rice (Oryza sativa L.) establishment in puddled soils in rice–rice and rice–wheat (Triticum aestivum L.) systems in Asia, requires a large amount of labor and water, which are becoming scarce and expensive. Growing more food with the same production costs or even reduced costs and sustaining the quality of the natural resource base are a major concern. On-farm trials were conducted in Chuadanga District of Bangladesh during the wet season as monsoon rice (aman) and during the dry season as winter rice (boro) in 2006–07 to evaluate the effects of establishment methods with improved crop management on productivity, resource (land, water, and labor) use, and economic return. Rice was established by sowing in line with a drum seeder on conventional tilled puddled soils (CT-DrumR) and by transplanting in line on the day of CT-DrumR (CT-TPR1) and 30 and 35 days after CT-DrumR (CT-TPR2) in aman and boro seasons, respectively. Farmers’ usual transplanting time corresponds to the day of CT-TPR2. Grain yields in CT-DrumR and CT-TPR2 were similar but the crop occupied the main field 22–24 days longer in CT-DrumR than in CT-TPR2, resulting in lower productivity (45 kg grain ha⁻¹ day⁻¹ vs. 55 kg grain ha⁻¹ day⁻¹) in both seasons. Drum-seeded rice matured earlier by 8 and 11 days, received 12% and 6% less irrigation water, saved 19 and 24 person-days ha⁻¹, and gave higher gross margins of 6% and 4% but input costs increased by 20% and 12% than CT-TPR2 in aman and boro seasons, respectively. There is a need to examine these benefits of drum-seeded rice in relation to the feasibility of adoption by farmers.     

Prediction of bread wheat baking quality using an optimized GlutoPeak®-Test method

The GlutoPeak^®-Test (GPT) as a rapid small-scale technique was optimized to evaluate the gluten aggregation properties and to predict the loaf volume, on the basis of a multiyear and multilocation analysis of wheat samples, using different solvents. 5 % lactic acid and 1 % sodium chloride displayed significant GPT responses. Relationships between protein content, sedimentation value, GPT parameters and loaf volume were investigated. With 1 % sodium chloride, the torque 15 s before maximum torque (AM) presented the highest correlation with loaf volume of samples from 2013 to 2014 (r = 0.77, r = 0.63, p < 0.001, respectively). A multiple regression analysis indicated that the best prediction of loaf volume was a linear function of protein content and AM, explaining the variation in loaf volume by 63 % and providing an uncertainty of ±39 ml. The accuracy of the validation of the linear function leads to 64 % correct and to 36 % incorrect predictions of the loaf volume. This emphasizes that the application of the linear function of protein content and AM cannot replace the actual measurement of loaf volume, but it could be a useful rapid screening test in breeding for improved baking quality in bread wheat.     

Individual and combined effects of salinity and waterlogging on Cry1Ac expression and insecticidal efficacy of Bt cotton

Salinity, waterlogging and a combination of both stresses are severe threats to plant growth, development and yield of field-grown cotton (Gossypium hirsutum L.), but their individual or combined effects on insecticidal efficacy of Bacillus thuringiensis (Bt) transgenic cotton and the underlying mechanisms are not well understood. In the present study, two cotton cultivars (33B and SCRC17) containing the Cry1Ac insecticidal protein gene were planted in 10 L pots filled with soil and allowed to grow in a greenhouse. The potted plants were either treated with NaCl (5 mg/g, w/w), waterlogging, or a combination of both stresses at the three true-leaf stage, and levels of total soluble protein, Bt insecticidal protein, gossypol and the control efficacy as indicated by mortality of bollworm larvae were examined at 7-day intervals after stress. Waterlogging and a combination of salinity and waterlogging reduced total protein content by 40–46% and 45–65% and Bt protein content by 38–50% and 45–72% from 7 to 21 days after stress, relative to the non-stressed control, respectively. The control efficacy was significantly reduced by either waterlogging or the combined stress. Regression analysis indicated that Bt protein content was correlated to total soluble protein content (R² = 0.7677*), while Bt cotton efficacy was correlated to Bt protein level (R² = 0.7917**). Salinity reduced Bt protein by 11–22% and total soluble protein by 5.7–7.2% from 7 to 21 days after NaCl stress, but did not result in reduction in control efficacy. It is concluded that reduced bollworm control efficacy under waterlogging or the combined stress could be mainly attributed to the declined levels of Bt protein, which is closely associated with the inhibited nitrogen metabolism by stresses. As one of the secondary compounds that are toxic to pests, increases in gossypol may be involved in maintaining the efficacy when Bt protein level was reduced under salinity.     

Phosphorus accumulation and depletion in soils in wheat–maize cropping systems: Modeling and validation

Long-term (over 15 years) winter wheat (Triticum aestivum L.)–maize (Zea mays L.) crop rotation experiments were conducted to investigate the accumulation of phosphorus (P) at five sites differing geographically and climatically in China. The results showed that, in soils without P added, the concentration of soil P extracted by 0.5 mol L⁻¹ NaHCO₃ at pH 8.5 (Olsen-P) decreased with cultivation time until about 3 mg kg⁻¹, afterwards it remained constant. The trend of decrease in Olsen-P in soils without P added could be described by an exponential function of time. The concentration of Olsen-P in soils with P fertilizers increased with cultivation time and the model of accumulation of Olsen-P in soils could be described using P application rate, crop yield and soil pH. The accumulation rate of Olsen-P in the long-term wheat–maize crop rotation experiments was 1.21 mg kg⁻¹ year⁻¹ on average. If the target yield of wheat and maize is 10 ton ha⁻¹ in the soil with pH 8, the increasing rates of Olsen-P in soils as estimated by the model will be 0.06, 0.36, 0.66, 0.95, 1.25 and 1.55 mg kg⁻¹ year⁻¹ when P application rates are 30, 40, 50, 60, 70 and 80 kg P ha⁻¹ year⁻¹, respectively. The models of accumulation of Olsen-P in soils were validated independently and could be used for the accurate prediction of accumulation rate of Olsen-P in soils with wheat–maize rotation systems. Also the application of the model was discussed for best management of soil P in agricultural production and environment protection.     

Rheological properties of starches with different amylose/amylopectin ratios

The rheological properties of corn starches with different amylose/amylopectin ratios (80/20, 50/50, 23/77, and 0/100) were systematically studied by Haake rheometry. The starches were initially pre-compounded with water to designated moisture content levels using a twin-screw extruder. A single-screw extruder with a slit capillary die was then used to characterize the shear stress and melt viscosity characteristics of sample pellets, as a function of both moisture content (19–27%) and extrusion temperature (110–140 °C). The melts exhibited shear thinning behavior under all conditions, with the power law index (0 < n < 1) increasing with increasing temperature and moisture content in the majority of cases. The higher the amylose content, the higher is the viscosity (for example, η increases from 277 Pa s to 1254 Pa s when amylose content increases from 0% to 80% under a certain condition), which is opposite to the sequence of molecular weight; amylopectin-rich starches exhibited increased Newtonian behavior. These rheological behaviors are attributed to the higher gelatinization temperature of amylose-rich starches, and in particular the multiphase transitions that occur in these starches at higher temperatures, and the gel-ball structure of gelatinized amylopectin.     

The Role of Dextrins in the Stickiness of Bread Crumb made from Pre-Harvest Sprouted Wheat or Flour Containing ExogenousAlpha-Amylase

Dextrins were extracted in water from bread made from pre-harvest sprouted wheat or standard flour supplemented with exogenousalpha-amylases. The dextrins were separated by gel permeation chromatography and the dextrin content (% of crumb weight) determined for different degree of polymerisation (DP) size classes; DP 1–2, DP 3–10, DP 11–50, DP 51–200 and DP >200. There were significant correlations between the dextrin content in each size class and crumb stickiness (r=0·84–0·91, 22 df ). The most significant correlation (r=0·96) was between total dextrin content and crumb stickiness. Addition of dextrins of various DP ranges from various sources to standard flour produced bread with sticky crumb. Again, the degree of stickiness was generally related to the amount of total dextrin in the crumb and not to size distribution of dextrins. In this instance, extensive enzymic hydrolysis of starch was not necessary to produce sticky crumb; the dextrins caused crumb stickiness directly. Addition of dextrins to reconstituted gluten–starch flour produced bread with unexpectedly low dextrin levels and correspondingly low stickiness scores. It is concluded that, to produce sticky crumb, high levels of dextrin of any size are necessary in the crumb; a sticky mass is produced when dextrins dissolve in the excess «free» water that is normally «bound» to starch, gluten and other insoluble components of bread crumb.     

Prior weakening of Macrophomina phaseolina and Fusarium propagules for enhancing efficiency of Brassica amendments

In a two year field study, the effect of varying intensities of sub-lethal heating on the efficiency of Brassica amendments in controlling viable populations of Macrophomina phaseolina and Fusarium oxysporum f sp. cumini was determined in an arid region of India. After 30 d of dry summer exposure of pathogen infested soil, incorporation of mustard residues and oil cake (0.18% and 0.04% w/w) and then applying one irrigation caused significant reduction by 75.3–81.3% in viable counts of M. phaseolina that causes dry root rot of legumes and by 93.9% in counts of F.o. f. sp. cumini causing wilt of cumin (Cuminum cyminum L.) at 0–15 and 16–30 cm depths. Increasing duration of summer exposure to 60 d improved the reductions in viable propagules of M. phaseolina by 83.6–90.4% and in F.o. f. sp. cumini by 78.2–94.8% at same soil depths. At certain heat levels, reduction in viable population of Fusarium due to amendments and irrigation was greater than that recorded in Macrophomina. Significantly low levels of reduction in pathogenic propagules of Macrophomina (63.9–71.4%) and Fusarium (48.0–57.2%) under shade compared to unshaded conditions indicated that mild heating did not cause discernible weakening effect. In second season also, 89.2–91.5% and 78.5–95.8% reduction in counts of Macrophomina and Fusarium, respectively was achieved by the application of amendments after 60 d of summer exposure at 0–30 cm soil depth. These results suggested a new approach to improve the control of soil-borne plant pathogens in hot arid regions by combining prolonged sub-lethal heating, effective naturally available on-farm wastes as soil amendments and one summer irrigation.     

Integrating the effects of climate and plant available soil water holding capacity on wheat yield

In the Mediterranean farming systems of the Western Australian wheatbelt, crop yields are influenced primarily by the amount and distribution of rainfall and the soil's capacity to hold moisture. The wheatbelt's growing season rainfall varies in the range of 200–400 mm (average) and the plant available water holding capacity (PAWC) of soils is generally in the 40–140 mm range. The grain yield of wheat is sensitive to this combination of small rainfall and small storage capacity.In this study, we explore the relationship between yield and PAWC using a combination of simulation modelling and analysis of field data. Crop yields and soil properties were monitored in detail at 17 locations (PAWCs 43–131 mm) across six seasons (1997–2005). Crop yields were also simulated using the APSIM crop simulator (RMSE = 311 kg/ha) to evaluate the long-term relationship between crop yield and plant available water capacity using 106 years of historical climate data.The relationship between crop yield and PAWC varied with season, and two important factors emerged: (1) for PAWC < 65 mm, there was a linear relationship with crop yields that ranged from 17 kg/ha/mm to 58 kg/ha/mm of PAWC across seasons; (2) for PAWC 65–131 mm the crop yield response to PAWC ranged from 11.5 kg/ha/mm in 45% of seasons to no response.The impact of PAWC on crop yield was reduced in seasons with late rainfall, and magnified in seasons with reduced rainfall late in the growing season. Six distinct season types with different yield–PAWC relationships are identified and season-specific management strategies that exploit within-field variation in PAWC are developed to manage the spatial variation of PAWC in a field.     

Optimization of ultrasound-assisted extraction of defatted wheat germ proteins by reverse micelles

In this work, an ultrasound-assisted procedure for the extraction of defatted wheat germ proteins by reverse micelles was established. Response surface methodology (RSM) was used to optimize the ultrasound-assisted extraction (UAE) parameters (ultrasonic output power, ultrasonic time and pulse mode) for enhancing the forward extraction efficiency of defatted wheat germ proteins by implementing a three-level, three-variable Box–Behnken experimental design. The independent variable with the largest effect on response was X₂ (ultrasonic time), followed by X₁ (ultrasonic output power) and X₃ (pulse mode). The optimum extraction conditions were found to be ultrasonic output power 363 W, ultrasonic time 24 min and pulse mode 2.4 s on and 2 s off (2.4 s:2 s). Under these conditions, the forward extraction efficiency of defatted wheat germ proteins can increase from 37% to 57%, and the final protein extraction efficiency by reverse micelles can reach 45.6%, making the advantage of reverse micelles much more obvious than alkaline extraction and isoelectric precipitation on the separation of protein.     

Effects of sprayers and nozzles on spray drift and terminal residues of imidacloprid on wheat

In pesticide application, it can be obtained by using appropriate nozzles and sprayers to reduce spray drift and pesticide residues. In this study, a field trail was conducted to determine the spray drift and pesticide residue of imidacloprid on wheat, using three types of flat fan nozzles from the LECHLER Company (LU120-02, AD120-02, IDK120-02) and two types of sprayers (guided-baffle shield sprayer (GBSS) and conventional sprayer (CS)). The spray drift (measured with both airborne and sediment samplers) and terminal residues on wheat were analyzed by liquid chromatography triple-quadrupole mass spectrometry. The results show that both the sediment drift and airborne spray profile were greatest for the LU120-02 nozzle, intermediate for the IDK120-02 nozzle, and lowest for the AD120-02 nozzle. The shielded sprayer gave one third of the drift recorded by airborne samplers and one half of the drift recorded by sediment samplers, compared with results from the CS. Airborne spray drift decreased with increasing height. The imidacloprid residues on wheat grain from different application methods were all below the maximum residue limit (MRL) suggested by EU (0.1 mg/kg) or China (0.05 mg/kg) and no imidacloprid residue was detected on wheat straw. Considering the factors on environment protection, food safety, and biological efficacy, the AD120-02 nozzle and GBSS performed better compared with other nozzles and sprayers. The combination of AD120-02 nozzle with a GBSS is likely to be the optimum application method on wheat.     

Valorization of three varieties of grape

In the present investigation, seed methanolic extracts of three Vitis vinifera (Muscat d’Italie, Syrah and Carignan) were assayed for their antioxidant activities. Results showed that there are strong variations in the contents of total phenols (440.97–121.94 mg GAE g⁻¹ DW), flavonoids (48.07–16.81 mg EC g⁻¹ DW) and tanins (37.15–14.9 mg EC g⁻¹ DW) from the studied seeds. The phenolic composition of these extracts was determined by RP–HPLC after acid hydrolysis. The main phenolic compound was quercetin with 27.2% in Muscat d’Italie, 48.8% in Syrah and 28.4% in Carignan. Besides, all seed extracts showed remarkable DPPH radical scavenging activity with IC₅₀ values ranged from 1.8 to 30 μg ml⁻¹. EC₅₀ values of reducing power activity ranged from 100 to 120 μg ml⁻¹. The high phenolic content and the considerable antioxidant activities of vitis seed extracts could potentially be considered as an expensive source of natural antioxidants.