Use of High-Resolution X-Ray Micro-Computed Tomography for the Analysis of Internal Structural Changes in Maize Infected with <Emphasis Type="Italic">Fusarium verticillioides</Emphasis>

X-ray micro-computed tomography (X-ray micro-CT) is a non-destructive, three-dimensional (3D) imaging and analysis technique for the investigation of internal structure of a large variety of materials, including agricultural produce. As a relatively new method in the field of food science, X-ray micro-CT has been applied successfully to obtain micro-structural information of foods undergoing different physical and chemical changes. In this study, high-resolution X-ray micro-CT was used for non-destructive analysis of the internal structure of maize kernels infected with Fusarium verticillioides. The major anatomical features of the maize kernel were identified based on their differences in X-ray attenuation, i.e. the germ, scutellum, vitreous and floury endosperm. Fungal infection caused changes in the internal structure of the kernels over time, which included a decrease in total kernel volume and an increase in total volume of void space, with more voids observed in the germ and floury endosperm regions. No significant (P > 0.05) difference was observed between the control and the infected kernels; it was apparent that the changes observed in the infected kernels were not solely as a result of fungal growth. The grey level histograms of the control and infected kernels shifted to the lower grey value intensity range over time indicating an increase in void space within the kernels. In the 3D images, the increase in total volume of void space with fungal progression was clearer and the effect of fungal damage on the internal structure was evident.     

基于Kernel-ICA和X-ray成像的品种分类研究

对农作物品种正确分类是作物分类学的重要内容,为考察X-ray成像技术对小麦品种分类研究的有效性,基于软X-ray成像仪采集的3品种(Kama,Rosa and Canadian)每个品种70个籽粒,共210个籽粒样本的X-ray扫描图像,并针对其7个形态几何特征(面积、周长、紧致度、籽粒长度、宽度、偏斜度、种子腹沟长度),提出了一种使用Kernel-ICA的方法先对特征进行优化,再进行小麦品种的聚类与识别的方法,并与K-means、C-means 2种聚类方法以及基于工神经网络(ANN)和支持向量机(SVM)2种识别方法的分类结果进行比较,结果发现:分类正确率从高到低分别为:Kernel-ICA、SVM、C-means、K-means、BP-ANN,分类正确率分别为:91.9%、90.5%、89.5%、87.1%、86.9%。研究提出的Kernel-ICA的方法,聚类优化和识别能力较强,对软X-ray成像的小麦品种进行分类,已基本上满足农艺上对小麦品种分类需要,对农作物种质资源鉴别和作物品种分类研究具有积极意义。     

Short communication: Physicochemical features and microbial community of milk kefir using a potential probiotic Saccharomyces cerevisiae KU200284

The aim of this study was to analyze the β-glucan contents, physicochemical features, and microbial communities in milk kefir prepared using Saccharomyces cerevisiae KU200284 isolated from cucumber jangajji, a fermented vegetable commonly eaten in Korean. Three types of milk kefir were manufactured, with (1) activated kefir grain, (2) activated kefir grain with commercial S. cerevisiae BOF, and (3) activated kefir grain with S. cerevisiae KU200284. β-Glucan contents of milk kefir using kefir grain and kefir grain with S. cerevisiae strains BOF and KU200284 were 8.29, 8.59, and 8.57%, respectively. The pH, titratable acidity, viscosity, Brix level, and alcohol contents of milk kefir using kefir grain with S. cerevisiae strains were acceptable compared with milk kefir using only kefir grain. In milk kefir produced using kefir grains and S. cerevisiae strains, 16S rRNA reads showed representative strains of Lactobacillus kefiranofaciens (>72% relative abundance) and Acetobacter fabarum (>16% relative abundance). In particular, milk kefir using kefir grain with S. cerevisiae KU200284 had the highest relative abundance of L. kefiranofaciens. In addition, the internal transcribed sequence (ITS) rRNA reads in tested milk kefir showed representative strains of Kluyveromyces marxianus (>52% relative abundance) and Saccharomyces cerevisiae (>16% relative abundance). In contrast, milk kefir using S. cerevisiae strains had higher relative abundance of S. cerevisiae (>37%). The β-glucan production, physicochemical properties, and microbial community profiling indicate that S. cerevisiae KU200284 could be used in functional dairy products as a starter culture.     

Effect of nonthermal plasma on physico-chemical,amino acid composition,pasting and protein characteristics of short and long grain rice flour

Nonthermal plasma (NTP) is a novel technology with potential applications in food property and functionality modification. In this study, short and long grain rice flours were exposed to different plasma intensities and resulting ozone concentrations, and their physicochemical, amino acid composition, X-ray diffraction, pasting properties and protein profile were evaluated. The L*, b*, blue value, λ_max, pH, transmittance, swelling power, and syneresis of both rice types increased with NTP treatment while a* decreased. X-ray diffraction revealed a decrease in crystallinity with NTP treatment. Long grain rice showed higher peak viscosity, breakdown viscosity and lower pasting temperature as compared to short grain rice due to higher amylose content. Glutamic acid, asparagine, serine histidine, threonine, γ-aminobutyric acid, tryptophan, isoleucine, phenylalanine and proline content increased with NTP treatment in both rice types. SDS page analysis did not reveal any effect of NTP treatment on banding pattern of total protein of both rice types.     

What does global warming mean for stored-grain protection? Options for Prostephanus truncatus (Horn) control at increased temperatures

Global climate change is expected to accelerate reproduction, development and activity of stored-product insect pests and degradation of grain protectants hence compromising efficacy of available storage pest management technologies. However, there is little information on these effects. The current laboratory study examined the effect of increasing temperatures on the efficacy of stored maize grain protectants and hermetic containers in controlling Prostephanus truncatus (Horn). In Experiment I, three commercial synthetic grain pesticides (cocktails of an organophosphate and a pyrethroid or a neonicotinoid) and two farmer-practices (neem leaf powder and wood ash) were tested on shelled maize grain. In Experiment II, four storage containers, viz Purdue Improved Crop Storage (PICS) bag, Super Grain bag (SGB), metal silo (MS) and polypropylene bag (PP) (all containing untreated maize) were tested. Both experiments were conducted for 12 weeks at 32 °C, 38 °C and mean ambient temperature of 26 °C; with three replicates per treatment. All treatments were artificially infested with laboratory-reared adult P. truncatus. Sampling was at baseline (0 weeks) and 4-weekly intervals. Overall, results showed significant differences in grain damage and weight losses between non-synthetic and synthetic grain protectants in all treatments at all tested conditions. The hermetic storage containers kept mean insect grain damage below 6.4% compared to 24.5% in the untreated control at all the experimental conditions. These results indicate that the use of synthetic grain protectants and hermetic storage containers (SGB, PICS and MS) in the management of P. truncatus may not be negatively affected by projected warmer temperatures of 32 °C or 38 °C; suggesting these storage technologies will remain efficacious under sub-Saharan Africa’s warming climates.     

Grain challenge affects systemic and hepatic molecular biomarkers of inflammation,stress, and metabolic responses to a greater extent in Holstein than Jersey cows

Long-term feeding of high-grain diets to dairy cows often results in systemic inflammation characterized by alterations in acute-phase proteins and other biomarkers, both in plasma and immune-responsive tissues like the liver. The molecular and systemic changes that characterize an acute grain feeding challenge remain unclear. The current study involved 6 Holstein and 6 Jersey cows in a replicated 2 × 2 Latin square. Periods (10 d) were divided into 4 stages (S): S1, d 1 to 3, served as baseline with total mixed ration (TMR) ad libitum; S2, d 4, served as restricted feeding, with cows offered 50% of the average daily intake observed in S1; S3, d 5, a grain challenge was performed, in which cows were fed a TMR ad libitum without (CON) or with an additional pellet wheat-barley (1:1; HIG) at 20% of dry matter intake top-dressed onto the TMR; S4, d 6 to 10, served as recovery during which cows were allowed ad libitum access to the TMR. Among the 28 biomarkers analyzed in blood 12 h after grain challenge on d 5, the concentrations of fatty acids and bilirubin increased in HIG Holstein but not Jersey cows. In Holsteins, feeding HIG also increased total protein and albumin while decreasing ceruloplasmin, myeloperoxidase, and alkaline phosphatase concentrations. At the molecular level, hepatic genes associated with inflammation (IL1B, IL6, TNF, TLR4, MYD88, and NFKB1) were upregulated in Holstein cows fed HIG versus CON. Despite such response, expression of the acute-phase proteins SAA and HP in Holsteins fed HIG compared with CON was markedly downregulated. In Holsteins fed HIG versus CON, the marked downregulation of SCD, ELOVL6, and MTTP along with upregulated CPT1A, ACOX1, and APOA5 indicated alterations in fatty acid and lipoprotein metabolism during grain challenge. Genes related to ketogenesis (HMGCS2 and ACAT1) were upregulated in Jerseys, and gluconeogenic genes (PDK4 and PCK1) were upregulated in Holstein cows fed HIG, suggesting alterations in ketone body and glucose production. Expression of phosphorylated p70S6K1, RPS6, and 4EBP1 proteins, as well as total mechanistic target of rapamycin (mTOR) protein, decreased in Holsteins fed HIG, whereas phosphorylated mTOR and 4EBP1 proteins increased in Jerseys fed HIG. From a metabolic and inflammatory biomarker standpoint, data indicate that Jersey cows better tolerated the acute grain challenge. Alterations in mTOR signaling proteins in both Jerseys and Holsteins fed HIG suggest a potential role for exogenous AA in the hepatic adaptations to grain challenge. It remains to be determined if these acute responses to a grain challenge can elicit long-term liver dysfunction, which could negatively affect welfare of the cow.     

Predicting Prostephanus truncatus (Horn) (Coleoptera: Bostrichidae) populations and associated grain damage in smallholder farmers’ maize stores: A machine learning approach

Prostephanus truncatus is a notorious pest of stored-maize grain and its spread throughout sub-Saharan Africa has led to increased levels of grain storage losses. The current study developed models to predict the level of P. truncatus infestation and associated damage of maize grain in smallholder farmer stores. Data were gathered from grain storage trials conducted in Hwedza and Mbire districts of Zimbabwe and correlated with weather data for each site. Insect counts of P. truncatus and other common stored grain insect pests had a strong correlation with time of year with highest recorded numbers from January to May. Correlation analysis showed insect-generated grain dust from boring and feeding activity to be the best indicator of P. truncatus presence in stores (r = 0.70), while a moderate correlation (r = 0.48) was found between P. truncatus numbers and storage insect parasitic wasps, and grain damage levels significantly correlated with the presence of Tribolium castaneum (r = 0.60). Models were developed for predicting P. truncatus infestation and grain damage using parameter selection algorithms and decision-tree machine learning algorithms with 10-fold cross-validation. The P. truncatus population size prediction model performance was weak (r = 0.43) due to the complicated sampling and detection of the pest and eight-week long period between sampling events. The grain damage prediction model had a stronger correlation coefficient (r = 0.93) and is a good estimator for in situ stored grain insect damage. The models were developed for use under southern African climatic conditions and can be improved with more input data to create more precise models for building decision-support tools for smallholder maize-based production systems.     

Identification of Sicilian landraces and Canadian cultivars of lentil using an image analysis system

Seed colour and size determine the appearance of grain legumes such as lentils (Lens culinaris Medik.). Currently, these characteristics are assessed by visual inspection of grain; it is slow and subjective, for this reason an objective imaging system was developed in Canada to measure bulk seeds lentil colour and size in a consistent manner for lentil quality colour grading.The Canadian imaging method, using image captured by a flatbed scanner, was modified in collaboration with the Stazione Sperimentale di Granicoltura (Research Institute in Sicily) to measure seed size, shape and mean colour on individual seeds; each seed imaging data were computed with a Linear Discriminant Analysis (Classifier) to identify five Sicilian landraces of Lens culinaris Medik., precisely Aragona, Bronte, Leonforte, Ustica and Villalba and three common Canadian accessions, cv Laird, cv Crimson and cv Eston.The performance of the classifier was 99.8% for the training sets and 97.1% for the independent test set. In addition to commercial international trade, lentil seed characterisation is very important to identify and catalogue in a biodiversity conservation program.     

Detection of External and Internal Insect Infestation in Wheat by Near-Infrared Reflectance Spectroscopy

Near-infrared spectroscopy (NIR) in the reflectance mode was investigated for the rapid, automatic and non-destructive detection of insect stored-grain pests external or internal to wheat kernels. Convincing calibration performance was obtained for external adult Oryzaephilus surinamensis (L) (saw-toothed grain beetle) in unmilled samples including varieties Beaver (soft wheat) and Mercia (hard wheat) at two moisture contents. With this large substrate variability, the method could differentiate between uninfested samples and samples with approximately 270 insects kg⁻¹ or more. Milling made no improvement. Large spectral differences were observed between uninfested kernels and kernels infested internally with Sitophilus granarius (L) (grain weevil) larvae or pupae, arising from both a changed chemical composition and physical structure. Single uninfested and infested kernels were discriminated by their second derivative (d²) spectra. For both external and internal infestation there was substantial evidence that insect protein and/or chitin and moisture were being detected. NIR should be useful as a rapid method of detection.     

An investigation into the use of an X-ray technique in the study of pre-emergent stages of Sitophilus oryzae (L.) developing in Manitoba wheat

The suitability of using an X-ray technique to study pre-emergent stages of Sitophilus oryzae (L.) developing in Manitoba wheat was investigated. A sample of grain was radiographed once every other working day subsequent to exposure to adult S. oryzae for 24 hr, until the emergence of the F1 generation. Eggs and small larvae were not detected in this manner, but after 13 days larvae were detected with increasing efficiency. Pupae and adults within the grain could be detected and were easily distinguished from larvae and pupae.The development of S. oryzae in individual wheat grains was investigated by sticking each grain of wheat to the Sellotape base of an aluminium cell prior to exposure to one female S. oryzae adult, and subsequently radiographing every other day for 23 days. Larvae were positively identified in grains as early as 9 days after oviposition by tracing back their development in the developed X-ray films, and seven suspected (although not positively identified) eggs were seen on the first day after oviposition.A quantity of grain was X-rayed immediately prior to fumigation and at intervals after fumigation. The efficiency with which dead insects were detected decreased with time after fumigation.     

Detection and quantification of the insect pest Rhyzopertha dominica (F.) (Coleoptera: Bostrichidae) in rice by qPCR

The early detection of insects during grain storage and processing remains a major issue for the cereal industry, especially when immature stages are hidden inside the grain kernels. For this reason, we developed a qPCR method to detect and quantify one of the main pests of stored products in rice: the coleopteran internal feeder Rhyzopertha dominica. For that purpose, a specific primer set was designed to amplify artificial infestations of this pest in rice. Then, using a regression model, a standard curve was generated that correlated individuals to adult equivalent DNA quantity (inverse of the C_t value). Results revealed that the designed primer set was specific for R. dominica when tested against the other 4 common internal feeders in grain. The technique showed to be accurated (DNA was detected in more than 73% of the samples) and sensitive to insect presence (i.e. from 0.02 adults, 0.1 3rd instar to pupae or 13 egg to 2nd instar detectable per kg of rice). Moreover, the detection of R. dominica was strongly associated with a given infestation size: DNA quantity increased along with the size of the population. The use of the described qPCR protocol in grain and milling factories may enhace the critical detection and quantification of R. dominica populations in raw materials and processed food.     

Detection of granary weevil Sitophilus granarius (L.) eggs and internal stages in wheat grain using soft X-ray and image analysis

In order to prevent grain mass and quality losses, rapid methods for early detection of insect infestation of cereal grain during trade and storage are urgently needed. Amongst many options, the soft X-ray method using roentgenograms is one of the most frequently applied. It has been shown that when some corrections for working parameters of the equipment used are made and some modification of the digital image analysis introduced, the soft X-ray method is suitable for accurate detection of granary weevil eggs laid in wheat kernels if at least 5 days after oviposition have elapsed.     

Artificial ageing of softwood joints and its effect on internal bond strength with special consideration of flat-to-end grain joints

The effect of ageing processes on internal bond strength of three-part specimens produced from Norway spruce wood (Picea abies Karst.) bonded with one-component polyurethane (PUR), two-component emulsion polymer isocyanate (EPI), melamine-urea-formaldehyde (MUF) or phenol-resorcinol-formaldehyde (PRF) adhesive was studied. By varying the grain angle of the middle part from 0° (parallel to grain of the surface layers) to 90° (perpendicular to grain of the surface layers) in incremental steps of 10° the effect of grain direction was investigated. The specimens were exposed to a three-step ageing cycle lasting for seven days (50°C/95% relative humidity (rH), ?20°C/65?C70% rH and 75°C/15% rH) which was repeated twelve and twenty-four times, respectively. In general, a decrease in internal bond strength of the exposed specimens was observed. For all tested adhesive systems, influence of ageing processes was more pronounced for flat-to-end grain joints compared to longitudinal joints. For samples bonded with PUR adhesive strength reduction was lower compared to the other adhesives used.     

Seasonal chemical–physical changes of PGI Pachino cherry tomatoes detected by magnetic resonance imaging (MRI)

Magnetic resonance imaging (MRI) has been used to study the variations of internal structure and chemical–physical characteristics of cherry tomatoes (Lycopersicon esculentum cv. Shiren), one the most economically valuable horticultural crops, in different harvesting seasons. In particular, the study focused on PGI (Protected Geographical Indication) Pachino cherry tomatoes, characterised by taste and nutritional value, notably in the winter production, amounting about 500 ton/year.     

Multifractal properties of pore-size distribution in apple tissue using X-ray imaging

The pore-size distribution (PSD) has an important influence on the complex gas transport phenomena (O₂ and CO₂) that occur in apple tissue during storage under controlled atmosphere conditions. It defines the apple tissue microstructure that is correlated to many other apple properties. In this article multifractal analysis (MFA) has been used to study the multiscale structure of the PSD using generalized dimensions in three varieties of apples (Jonagold, Greenstar, and Kanzi) based on X-ray imaging technology (8.5 μm resolution). Tomographic images of apple samples were taken at two positions within the parenchyma tissue: close to the peel and near to the core. The images showed suitable scaling properties. The generalized dimensions were determined with an R² greater than 0.98 in the range of moment orders between −1 and +10. The variation of D_q with respect to q and the shape of the multifractal generalized spectrum revealed that the PSD structure of apple tissue has properties close to multifractal self-similarity measures. Comparisons among cultivars showed that, in spite of the complexity and variability of the pore space of these apple samples, the extracted generalized dimensions from PSD were significantly different (p < 0.05). The generalized dimensions D₀, D₁, D₂, and the quantity D₀–D₂ could be used to discriminate tissue samples from different positions or cultivars. Also, high correlations were found between these parameters and the porosity (R² ? 0.935). These results demonstrate that MFA is an appropriate tool for characterizing the internal pore-size distribution of apple tissue and thus may be used as a quantitative measure to understand how tissue microstructure affects important physical properties of apple.     

Susceptibility of Ethiopian wheat varieties to granary weevil and rice weevil infestation at optimal and sub-optimal temperatures

Integrating varietal resistance with temperature manipulation during storage may provide a better option for protection of stored grains and may decrease reliance on the use of synthetic chemicals. The current study was conducted to determine the susceptibility of different varieties of wheat seed to the infestation by the granary weevil, Sitophilus granarius (L.), and rice weevil, Sitophilus oryzae (L.), at optimal (30 °C) and sub-optimal (19 °C) temperatures. Kernels of six wheat varieties namely, Danda'a, Digalu, ET-13-A2, Kakaba, Millennium, and Pavon-76 were examined over a period of 90 d. Significant interactions were detected between wheat varieties and storage temperature for progeny emergence, percentage of insect damaged kernels, grain weight loss, and amount of powder produced per gram of wheat. Kernels of Danda'a, infested with S. oryzae at 30 °C exhibited significantly lower mean progeny counts (13.3 live insects), lower percentage of grain weight loss (4.2%) and insect-damaged kernels (6.4%), and powder production (1.5 mg/g). Kernel weight and hardness index were negatively associated with percentage of insect damaged kernels and grain weight loss. Kernel diameter was positively associated with both of percentage of insect damaged kernels and grain weight loss. Wheat varieties with high Zeleny sedimentation values had lower percentage of insect-damaged kernels and grain weight loss. These results indicated that kernel weight, hardness index, and protein content are predominant factors contributing to wheat resistance against S. granarius and S. oryzae. The varieties Millennium and Danda'a can be considered with other integrated pest management approaches to reduce stored grain losses of wheat in Ethiopia.     

Classification and Authentication of Barley (<Emphasis Type="Italic">Hordeum vulgare</Emphasis>) Malt Varieties: Combining Attenuated Total Reflectance Mid-infrared Spectroscopy with Chemometrics

Attenuated total reflectance (ATR) mid-infrared (MIR) spectroscopy combined with chemometrics was explored as a tool to classify and authenticate Australian barley varieties. Grain samples (n = 162) were sourced from eight commercial barley varieties and analysed in the MIR range. Principal component analysis (PCA), discriminant partial least squares regression (PLS-DA), linear discriminant analysis (LDA) and soft independent modelling of class analogy (SIMCA) were used to classify the barley grain samples according to variety. PLS-DA correctly classified barley varieties between 91 and 100 %. The results have demonstrated the usefulness of ATR-MIR spectroscopy combined with chemometrics as a rapid method to classify barley grain samples according to their variety. Although MIR is not routinely available at the receival point in most of the cereal trade companies, it has the potential to be used in breeding programmes.     

Microwave treatment of <Emphasis Type="Italic">Eucalyptus macrorhyncha</Emphasis> timber for reducing drying defects and its impact on physical and mechanical wood properties

Microwave is a useful and proven tool for increasing permeability of refractory wood and, thereby, it can be used for reducing drying time and defects. However, strength loss is always a concern. In this study, green timber boards were treated with microwave in two intensities, low microwave (LMW), 89 kWh/m³, and high microwave (HMW), 95 kWh/m³, and compared with control boards. Samples of all three treatments were kiln dried together. Density and selected mechanical properties were also assessed after drying. LMW, the treatment which presented the best results, showed reduction in some drying defects, such as collapse (20%), surface check length (84%), internal check length (50%) and internal check width (70%). Density, MOE and MOR on static bending were unchanged, whereas reductions in shear strength (13%) and compression strength parallel to grain (10%) were observed. HMW, on the other hand, produced higher strength reductions and more drying defects than LMW. Fine adjustments of LMW microwave power might bring drying benefits without strength losses.     

A comparison of screening methods for insect contamination in wheat

In collaboration with the United States Department of Agriculture and a number of major milling companies, the “Insect-Detect” immunoassay for analyzing insect contamination in grains has been compared with three more traditional methods, X-ray analysis, cracking and flotation, and the insect fragment test (IFT). Testing was carried out in blind fashion using clean wheat samples that were spiked with differing numbers of grain kernels infested with late instar larvae of the granary weevil (Sitophilus granarius (L.)). Three different laboratories analyzed the samples for each of the four methods. The collaborative trials showed that the insect immunoassay clearly provided the most accurate measurement of actual insect infestation, followed by X-ray analysis. While both cracking and flotation and IFT procedures provided a general measure of contamination, they showed much greater variability.