Quality of packaged romaine lettuce hearts exposed to low-dose electron beam irradiation

We investigated the effects of low-dose electron beam irradiation (1.0, 1.5 and 3.2 kGy) on the quality of commercially prepackaged fresh romaine lettuce hearts. The impact of the irradiation treatment on the functionality of the package was also evaluated. Irradiated samples showed slight changes in color, but these changes were not significantly different (P >0.05) from the nonirradiated (control) samples. Sample firmness decreased by 49.58% (leaves) and 29.13% (ribs), as the dose level increased. Sensory attributes such as overall quality, color, sogginess, and off-flavor were found less acceptable at the higher dose level. Irradiation affected the respiration rates inside the packages, with lower (10.38%) O₂ and higher CO₂ levels than the control. Irradiation at 1.5 and 3.2 kGy dose levels improved the oxygen barrier capability of the low-density polyethylene (LDPE) bags (7.67% and 4.48%, respectively). Water vapor permeability was unaffected at all the irradiation dose levels. The stiffness of LPDE films did not change due to irradiation treatment. Results from sensory evaluation of produce overall quality suggest a potential fungicidal effect of low-dose irradiation (1.0 kGy) of packaged romaine lettuce hearts without altering the overall quality of the produce as well as the LDPE-packaging characteristics.     

Oversampling methods for machine learning model data training to improve model capabilities to predict the presence of Escherichia coli MG1655 in spinach wash water

We assessed the efficacy of oversampling techniques to enhance machine learning model performance in predicting Escherichia coli MG1655 presence in spinach wash water. Three oversampling methods were applied to balance two datasets, forming the basis for training random forest (RF), support vector machines (SVMs), and binomial logistic regression (BLR) models. Data underwent method-specific centering and standardization, with outliers replaced by feature-specific means in training datasets. Testing occurred without these preprocessing steps. Model hyperparameters were optimized using a subset of testing data via 10-fold cross-validation. Models were trained on full datasets and tested on newly acquired spinach wash water samples. Synthetic Minority Oversampling Technique (SMOTE) and Adaptive Synthetic Sampling approach (ADASYN) achieved strong results, with SMOTE RF reaching an accuracy of 90.0%, sensitivity of 93.8%, specificity of 87.5%, and an area under the curve (AUC) of 98.2% (without data preprocessing) and ADASYN achieving 86.55% accuracy, 87.5% sensitivity, 83.3% specificity, and a 92.4% AUC. SMOTE and ADASYN significantly improved (p < 0.05) SVM and RF models, compared to their non-oversampled counterparts without preprocessing. Data preprocessing had a mixed impact, improving (p < 0.05) the accuracy and specificity of the BLR model but decreasing the accuracy and specificity (p < 0.05) of the SVM and RF models. The most influential physiochemical feature for E. coli detection in wash water was water conductivity, ranging from 7.9 to 196.2 µS. Following closely was water turbidity, ranging from 2.97 to 72.35 NTU within this study.     

Amaranth Oil Increased Fecal Excretion of Bile Acid but Had No Effect in Reducing Plasma Cholesterol in Hamsters

Hamsters were fed for 4 weeks on four different diets: control (C) (balanced diet containing 20 % corn oil as the lipid source), hypercholesterolemic (H) (identical to C but containing 12 % coconut oil, 8 % corn oil and 0.1 % cholesterol as the lipid source), amaranth oil (A) (identical to H without corn oil but with amaranth oil), and squalene (S) (identical to H but admixed with squalene in the ratio found in amaranth oil). There were no significant differences in lipid profile, and in the cholesterol excreted in the animals’ feces from amaranth oil (A) and squalene (S) groups. Fecal excretion of bile acids was greater in the amaranth oil (A) and squalene groups (S) as compared to the other groups. The scores of steatosis and parenchymal inflammation observed in the amaranth oil (A) and squalene groups (S) were superior to the ones observed in the other groups. Our findings demonstrated that amaranth oil, and its component squalene, increased the excretion of bile acids but did not have a hypocholesterolemic effect in hamsters fed on a diet containing high amounts of saturated fat and cholesterol.     

Response surface modelling of the production of structured lipids from soybean oil using Rhizomucor miehei lipase

The production of structured lipids (SLs) by the acidolysis of soybean oil (SO) with a free fatty acid (FFA) mixture obtained from Brazilian sardine oil, catalysed by Rhizomucor miehei lipase (Lipozyme RM IM) in a solvent-free medium, was optimised by response surface methodology (RSM) using a three-factor central composite rotatable design. The best reaction conditions to achieve an adequate n-6/n-3 FA ratio were: sardine-FFA:SO mole ratio of 3:1, initial water content of the enzyme of 0.87% w/w, reaction time of 12 h, reaction temperature of 40 °C and 10% by weight of the enzyme (% w/w). Under these conditions, the incorporation of eicosapentaenoic acid (EPA) + docosahexaenoic acid (DHA) into the soybean oil reached 9.2% (% of the total FAs), leading to a significant reduction in the n-6/n-3 FA ratio from 11:1 to 3:1. Analysis of variance (ANOVA) showed that 95% (R² = 0.95) of the observed variation was explained by the model. Lack of fit analysis revealed a non-significant value for the model equation, indicating that the regression equation was adequate for predicting the degree of EPA + DHA incorporation under any combination of values of the variables. Easy ambient sonic-spray ionisation mass spectrometry (EASI-MS) was used for instantaneous characterisation of TAGs. After the enzymatic reaction, a great variety of new TAGs were formed containing EPA, DHA or both in the same molecule.     

Quality of electron beam irradiation of blueberries (Vaccinium corymbosum L.) at medium dose levels (1.0-3.2 kGy)

We assessed the effect of electron beam irradiation of packaged fresh blueberries at doses greater than 1.0 kGy on the quality attributes of the fruits. Irradiation experiments were conducted using a 10 MeV (18 kW) linear accelerator with single beam fixture. Fruits were stored at 5 °C and 70.4% RH for 14 days and tested at days 0, 3, 7 and 14 for physico-chemical, textural, microstructural, and sensory characteristics. Control samples consisted of non-irradiated fruits. Irradiation at doses higher than 1.1 kGy did affect (P<0.05) the texture of blueberries as the fruits became considerably softer and less acceptable throughout storage. Only irradiation at 3.2 kGy affected the color of blueberries by the end of storage. Irradiation slightly reduced the respiration rates of the blueberries by the end of storage. In terms of overall quality, texture and aroma, only fruits exposed to 3.2 kGy were found unacceptable by the sensory panelists. Irradiation at the dose levels used in this study did not affect the density, pH, water activity, moisture content, acidity and juiciness of blueberries. Electron beam irradiation of blueberries up to 1.6 kGy is a feasible decontamination treatment that maintains the overall fruit quality attributes.     

Assessing the spatio-temporal rates and patterns of land-use and land-cover changes in the Cerrados of southeastern Mato Grosso,Brazil

The Cerrados of central Brazil have undergone profound landscape transformation in recent decades due to agricultural expansion, and this remains poorly assessed. The present research investigates the spatial-temporal rates and patterns of land-use and land-cover (LULC) changes in one of the main areas of agricultural production in Mato Grosso State (Brazil), the region of Primavera do Leste. To quantify the different aspects of LULC changes (e.g. rates, types, and spatial patterns) in this region, we applied a post-classification change detection method, complemented with landscape metrics, for three dates (1985, 1995, and 2005). LULC maps were obtained from an object-based classification approach, using the nearest neighbour (NN) classifier and a multi-source data set for image object classification (e.g. seasonal Thematic Mapper (TM) bands, digital elevation model (DEM), and a Moderate Resolution Imaging Spectroradiometer (MODIS)-derived index), strategically chosen to increase class separability. The results provided an improved mapping of the Cerrados natural vegetation conversion into crops and pasture once auxiliary data were incorporated into the classification data set. Moreover, image segmentation was crucial for LULC map quality, in particular because of crop size and shape. The changes detected point towards increasing loss and fragmentation of natural vegetation and high rates of crop expansion. Between 1985 and 2005, approximately 42% (6491 km²) of Cerrados in the study area were converted to agricultural land uses. In addition, it was verified that cultivated areas are encroaching into fragile environments such as wetlands, which indicates the intense pressure of agricultural expansion on the environment.     

Hemisuccinate of 21-hydroxy-6,19-epoxyprogesterone: a tissue-specific modulator of the glucocorticoid receptor

The introduction of a hemisuccinate group at the 21-position of the passive antiglucocorticoid 21OH-6,19OP leads to a compound (21HS-6,19OP) with a notable activity profile toward the glucocorticoid receptor (GR). In contrast to the parent steroid, 21HS-6,19OP behaves as a pure agonist of GR activity in direct transactivation assays. However, the apoptotic effects of 21HS-6,19OP show that the effect depends on cell type: while 21HS-6,19OP is a pure agonist in L929 mouse fibroblasts, in thymocytes 21HS-6,19OP had significant antiglucocorticoid activity. This tissue-specific activity makes 21HS-6,19OP a novel selective GR modulator. To investigate the molecular basis of action of 21HS-6,19OP, we carried out molecular dynamics simulations (6 ns) of the GR ligand binding domain (LBD) complexed with 21HS-6,19OP. Our results indicate that the hemisuccinate moiety may play a key role in stabilizing the active conformation of the receptor dimerization interface, reverting the changes observed with the antagonist 21OH-6,19OP. Other changes in regions of the GR related to cofactor recruitment (possibly tissue-specific), could explain this particular activity profile.     

Castor oil hydrogenation by a catalytic hydrogen transfer system using limonene as hydrogen donor

The hydrogenation of castor oil was investigated using a catalytic transfer hydrogenation system in which palladium on carbon was the catalyst and limonene was the solvent and hydrogen donor. The highest percentage of castor oil modification occurred at 178°C using 1% Pd/C and an oil/limonene ratio of 1∶3. The optimized system presented very good reproducibility and 100% conversion of the ricinoleate. GC using a mass spectrometer as detector and ¹H NMR spectra of the products indicated that hydrogenation was accompanied by dehydrogenation leading to a mixture of 12-hydroxy and 12-keto stearic derivatives.