Efficacy of diflubenzuron plus methoprene against Sitophilus oryzae and Rhyzopertha dominica in stored sorghum

The efficacy of diflubenzuron (1 mg kg⁻¹)+methoprene (1 mg kg⁻¹) against Sitophilus oryzae (L.) and Rhyzopertha dominica (F.) in sorghum was evaluated in a silo-scale trial in southeast Queensland, Australia. Sorghum is normally protected from a wide range of insects by mixtures of grain protectants. The chitin synthesis inhibitor diflubenzuron was evaluated as a potential new protectant for S. oryzae in combination with the juvenile hormone analogue methoprene, which is already registered for control of R. dominica. Sorghum (ca 200 t) was treated after harvest in 2000 and assessed for treatment efficacy and residue decline during 6.5 months storage. The reproductive capacity of S. oryzae and R. dominica was greatly reduced in bioassays of treated sorghum throughout the trial, and efficacy remained relatively stable during the trial. An initial exposure of S. oryzae adults to treated sorghum for 2 weeks reduced F₁ progeny production of all strains by 80.8-98.8%, but a second exposure of 4 weeks reduced F₁ progeny production by 98.5-100%. In addition, the reproductive capacity of any S. oryzae progeny produced was greatly reduced. Exposure of R. dominica adults to treated sorghum for 2 weeks reduced F₁ progeny production of all strains by 99.6-100%, including a methoprene-resistant strain. The results indicate that S. oryzae or R. dominica adults invading sorghum treated with diflubenzuron (1 mg kg⁻¹)+methoprene (1 mg kg⁻¹) would be incapable of producing sustainable populations.     

Determination of selenium in garlic (Allium sativum) and onion (Allium cepa) by electro thermal atomic absorption spectrometry

A separation/enrichment procedure has been developed for the determination of selenium in garlic and onion samples by electrothermal atomic absorption spectrometry (ET-AAS) as a slurry sampling after preconcentration with 3,3-diaminobenzidine (DAB) reagent on the activated carbon. The influences of pH, time, amount of carbon and complexing reagent were outlined. The effect of acids used in the digestion of samples was also studied and compared. Selenium level was found to be 0.024 μg g⁻¹ for onion (n = 5; LOD – 0.5 μg L⁻¹; LOQ – 1.7 μg L⁻¹) and 0.015 μg g⁻¹ for garlic (n = 5; LOD – 1.3 μg L⁻¹; LOQ – 3.3 μg L⁻¹). Three different samples of garlic were analyzed by k₀-instrumental neutron activation analysis (k₀-INAA) at the Jozef Stefan Institute (JSI). The data obtained by k₀-INAA show that the content of selenium overlapped the results obtained by ET-AAS.     

Flow injection spectrophotometry using natural reagent from Morinda citrifolia root for determination of aluminium in tea

A flow injection (FI) spectrophotometric method with using natural reagent extracted from Morinda citrifolia root has been developed for determination of aluminium. The extract contained anthraquinone compounds which could react with Al³⁺ to form reddish complexes which had maximum absorption wavelength at 499.0 nm. The extract could be used as a reagent in FI system without further purification to obtain pure compound. A sensitive method for determination of aluminium in concentration range of 0.1-1.0 mg L⁻¹, with detection limit of 0.05 mg L⁻¹ was achieved. Relative standard deviations of 1.2% and 1.7% were obtained for the determination of 0.1 and 0.6 mg L⁻¹ Al³⁺ (n = 11). Sample throughput of 35 h⁻¹ was achieved with the consumption of 3 mL each of carrier and reagent solutions per injection. The developed method was successfully applied to tea samples, validated by the FAAS standard method. The method is simple, fast, economical and could be classified as a greener analytical method.     

Estimation of neuroprotective effects of Laurocerasus officinalis Roem. (cherry laurel) by in vitro methods

Dichloromethane, ethyl acetate, acetone, methanol, and water extracts prepared from the fruits and leaves of Laurocerasus officinalis Roem. (LO) (Rosaceae) were screened for their cholinesterase inhibitory activity against acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), the key enzymes in pathogenesis of Alzheimer's disease (AD), using ELISA microplate reader at 50, 100, and 200 ??g mL⁻¹. As AD is associated with oxidative stress, the antioxidant activity of the extracts was also tested by radical-forming methods against 2,2-diphenyl-1-picrylhydrazyl (DPPH), N,N-dimethyl-p-phenylendiamine (DMPD), and superoxide radicals as well as iron-related methods; iron-chelating capacity and ferric-reducing antioxidant power (FRAP) assays. Total phenol and flavonoid quantification was achieved using Folin-Ciocalteau and AlCl₃ reagents, respectively. The highest AChE (44.01 ± 1.75%) and BChE (19.91 ± 0.37%) inhibition was caused by the LO-leaf-methanol extract 200 ??g mL⁻¹, while it showed the best radical-scavenging activity against DPPH at 2000 ??g mL⁻¹. Only, the dichloromethane and water extracts of the fruits and the leaf water extract had an iron-chelating capacity, while the leaf methanol extract displayed the highest FRAP. The leaf methanol extract (113.45 ± 0.71 mg g⁻¹ extract) was found to be the richest in total phenols, while the leaf acetone extract (139.90 ± 4.64 mg g⁻¹ extract) had the most abundant amount of total flavonoids.     

Sensory,microbiological and chemical assessment of the freshness of red mullet (Mullus barbatus) and goldband goatfish (Upeneus moluccensis) during storage in ice

The shelf life of red mullet and goldband goatfish during ice storage were studied in terms of sensory, microbiological and chemical changes. The sensory acceptability limit was 8 days for goldband goatfish (Upeneus moluccensis) and 11 days for red mullet (Mullus barbatus) stored in ice. The TVC level was correlated with sensory assessment. The TVC exceeded 7 log cfu g⁻¹ after 8 days for goldband goatfish, and 11 days for red mullet. At the end of storage period, pH, TVB-N, TBA, FFA and PV for red mullet were 7.84, 47.19 mg/100 g, 0.69 mg MA kg⁻¹, 1.17% oleic acid and 1.58 meq O₂/kg and for goldband goatfish they were 7.53, 43.97 mg/100 g, 0.74 mg MA kg⁻¹, 1.62% oleic acid and 1.68 meq O₂/kg, respectively. In red mullet, agmatine, serotonin, histamine and dopamine became the dominant amines, reaching 7.30, 5.97, 2.52 and 2.31 mg/100 g, respectively. Also the dominant amines for goldband goatfish were 4.37, 3.88, 3.38 and 2.00 mg/100 g for histamine, agmatine, dopamine and putrescine, respectively.     

Trace element content of Boletus tomentipes mushroom collected from Yunnan,China

The contents of As, Cd, Cr, Cu, Fe, Hg, Mg, Mn, Ni, Pb, and Zn in eleven fruiting bodies of Boletus tomentipes were determined. The results showed the values of the studied elements decreased in the order: Mg (208–279 mg kg⁻¹) > Fe (106–137 mg kg⁻¹) > Mn (29.5–46.8. mg kg⁻¹) > Zn (18.7–23.1 mg kg⁻¹), > Cu (11.4–15.8 mg kg⁻¹) > Cr (3.36–4.78 mg kg⁻¹) > Pb (1.38–3.88 mg kg⁻¹) > Ni (1.68–3.01 mg kg⁻¹) > Cd (0.16–0.32 mg kg⁻¹) > As (0.10–0.24 mg kg⁻¹) > Hg (<0.06 mg kg⁻¹).     

Influence of grain and relative humidity on the mortality of Sitophilus oryzae (L.) adults exposed to ethyl formate vapour

Ethyl formate (EF) is being investigated as an alternative to phosphine and methyl bromide, for the fumigation of stored products. The compound has been found to have a rapid action against stored-product insects and shows promise as a fast-acting disinfestant.The response of Sitophilus oryzae adults to EF in a sealed system was studied. Insects were exposed to a range of EF doses for 24 h at 25 °C, with a range of grain quantities and relative humidities (r.h.). It was found that rapid mortality of S. oryzae adults in a sealed system was obtained, with a range of applied concentrations required to achieve 99% mortality. Concentrations as low as 11.2 mg L⁻¹, for the exposures without wheat at 97% r.h., achieved 99% mortality, whereas 81.2 mg L⁻¹ EF was required for the exposures carried out on 1500 g wheat in 2.7 L at 60% r.h. Modelling studies of the mortality data revealed that, in general, the presence or absence of grain had the largest influence on mortality, where the larger the grain quantity, the higher the required EF dose to achieve 99% mortality. To a lesser degree, the r.h. also influenced the observed mortality, where the higher the r.h., the lower the required EF dose to achieve 99% mortality. In this experimental system, the factors that determined the level of mortality were a complex interaction of the initial dosage concentration (C₀), concentration×time product (Ct), grain quantity and r.h.     

Antioxidant properties of hot water extracts from Agrocybe cylindracea

Agrocybe cylindracea (DC: Fr.) Mre. was available in the form of fruit bodies, mycelia and fermentation filtrate. From these three forms, hot-water extracts were prepared and their antioxidant properties were studied. Antioxidant activities of hot-water extracts from fruit bodies, mycelia and filtrate were 63.6%, 81.6% and 56.8% at 20 mg ml⁻¹, respectively. EC₅₀ values in reducing power were 2.72, 3.97 and 3.09 mg ml⁻¹ whereas those in scavenging abilities of 1,1-diphenyl-2-picrylhydrazyl radicals were 0.62, 1.66 and 0.82 mg ml⁻¹ for fruit bodies, mycelia and filtrate, respectively. At 20 mg ml⁻¹, the scavenging abilities of hydroxyl radicals were 80.1%, 57.0% and 54.3% for fruit bodies, mycelia and filtrate, respectively. With regard to EC₅₀ values in chelating abilities on ferrous ions, the hot-water extract from filtrate was better than that from mycelia. Total phenols were the major naturally occurring antioxidant components found in hot-water extracts and in the range of 23.74–30.16 mg g⁻¹. From EC₅₀ values obtained, it can be concluded that hot-water extracts from three forms of A. cylindracea were good in antioxidant properties.     

Nutrient contents of kale (Brassica oleraceae L. var. acephala DC.)

Fructose, glucose and sucrose, as the major soluble sugars and citric and malic acids, as the major organic acids, were identified and determined in kale (Brassica oleraceae L. var. acephala DC., black cabbage) leaves. Fructose was the predominant sugar (2011 mg 100 g⁻¹ dry wt) identified, followed by glucose (1056 mg 100 g⁻¹ dry wt) and sucrose (894 mg 100 g⁻¹ dry wt). The contents of citric and malic acids were at 2213 and 151 mg 100 g⁻¹ dry wt in the leaves. The 16:0, 18:2n − 6 and 18:3n − 3 fatty acids were the most abundant fatty acids in the leaves. Considering the level of these fatty acids, 18:3n − 3 was found to be the highest (85.3 μg g⁻¹ dry wt), contributing 54.0% of the total fatty acid content. Linoleic acid (18:2n − 6), being the second most abundant fatty acid was present at 18.6 μg g⁻¹ dry wt, contributing 11.8% of the total fatty acid content. In the seed oil of kale, 22:1n − 9 was the most abundant fatty acid (4198 μg g⁻¹ dry wt, 45.7%), with 18:2n − 6 (1199 μg g⁻¹ dry wt, 12.3%) and 18:1n − 9 (1408 μg g⁻¹ dry wt, 14.8%) being the second next most abundant fatty acids. The most abundant amino acid was glutamic acid (Glu) which was present at 33.2 mg g⁻¹ dry wt. Aspartic acid, which was the second most abundant amino acid, was present at 27.6 mg g⁻¹ dry wt and accounted for 10.2% of the total amino acid content of kale leaf. The amino acid content was assessed by comparing the percentages of the essential amino acids in kale leaf versus those of a World Health Organization (WHO) standard protein. The protein of kale leaf compares well with that of the WHO standard. Only one amino acid, lysine, had a score that fell below 100%; the lysine score of kale leaf was 95%. This study attempts to contribute to knowledge of the nutritional properties of the plant. These results may be useful for the evaluation of dietary information.     

Physiochemical properties and kinetics of glucoamylase produced from deoxy-d-glucose resistant mutant of Aspergillus niger for soluble starch hydrolysis

Glucoamylases (GAs) from a wild and a deoxy-d-glucose-resistant mutant of a locally isolated Aspergillus niger were purified to apparent homogeneity. The subunit molecular mass estimated by SDS–PAGE was 93 kDa for both strains, while the molecular masses determined by MALDI-TOF for wild and mutant GAs were 72.876 and 72.063 kDa, respectively. The monomeric nature of the enzymes was confirmed through activity staining. Significant improvement was observed in the kinetic properties of the mutant GA relative to the wild type enzyme. Kinetic constants of starch hydrolysis for A. niger parent and mutant GAs calculated on the basis of molecular masses determined through MALDI-TOF were as follows: k_cat = 343 and 727 s⁻¹, K_m = 0.25 and 0.16 mg mL⁻¹, k_cat/K_m (specificity constant) = 1374 and 4510 mg mL⁻¹ s⁻¹, respectively. Thermodynamic parameters for soluble starch hydrolysis also suggested that mutant GA was more efficient compared to the parent enzyme.     

Profiling of in vitro neurobiological effects and phenolic acids of selected endemic Salvia species

The ethyl acetate and methanol extracts from 16 Salvia L. species were screened for their inhibitory activity against acetylcholinesterase, butyrylcholinesterase, lipoxygenase, and tyrosinase; the enzymes linked to neurodegeneration. Their antioxidant activity was also tested using DPPH radical scavenging, metal-chelation, and ferric-reducing antioxidant power (FRAP) assays. Total flavonoid content of the extracts was determined by AlCl₃ reagent, while HPLC technique was applied for analysis of various phenolic acids in the extracts. The extracts exerted weak cholinesterase and tyrosinase inhibition, and remarkable inhibition against lipoxygenase (13.07 ± 2.73-74.21 ± 5.61%) at 100 μg ml⁻¹. The methanol extracts showed higher antioxidant activity in DPPH radical scavenging and FRAP assays. The extracts were analyzed for their gallic, protocateuchic, p-hydroxy-benzoic, vanillic, caffeic, chlorogenic, syringic, o- and p-coumaric, ferulic, rosmarinic, and tr-cinnamic acid contents and the methanol extract of Salvia ekimiana (153.50 mg 100 g⁻¹) was revealed to be the richest in terms of rosmarinic acid.     

Ethyl-carbamate determination by gas chromatography–mass spectrometry at different stages of production of a traditional Brazilian spirit

Ethyl carbamate (EC), which is probably carcinogenic to humans, can be produced during the alcoholic fermentation of sugar-cane juice to give cachaça. The stages to produce cachaça are obtainment of sugar-cane juice, sugar-cane fermentation to wine, and obtainment of distilled fractions and residue. In order to investigate the presence of EC in the wine and in the fractions of the distillation process, as well as in the vinasse (the residue left after distillation), gas chromatography–mass spectrometry was employed. After the fermentation phase, the wine showed an average content of 122 mg L⁻¹ of EC. Average EC content in distilled fractions was 59.7 mg L⁻¹ for head, 52 μg·L⁻¹ for heart and 1.57 mg L⁻¹ for tail. EC content was 53.1 mg L⁻¹ for vinasse. The results showed that it is essential to separate the head and tail fractions to ensure cachaça quality, with respect to EC content.     

Hollow fibre-based liquid phase microextraction combined with high-performance liquid chromatography for the analysis of flavonoids in Echinophora platyloba DC. and Mentha piperita

A simple, inexpensive and efficient three phase hollow fibre liquid phase microextraction (HF-LPME) technique combined with HPLC was used for the simultaneous determination of flavonoids in Echinophora platyloba DC. and Mentha piperita. Different factors affecting the HF-LPME procedure were investigated and optimised. The optimised extraction conditions were as follows: 1-octanol as an organic solvent, pH_donor = 2, pH_acceptor = 9.75, stirring rate of 1000 rpm, extraction time of 80 min, without addition of salt. Under these conditions, the enrichment factors ranged between 146 and 311. The values of intra and inter-day relative standard deviations (RSD) were in the range of 3.18–6.00% and 7.25–11.00%, respectively. The limits of detection (LODs) ranged between 0.5 and 7.0 ng mL⁻¹. Among the investigated flavonoids quercetin was found in E. platyloba DC. and luteolin was found in M. piperita. Concentration of quercetin and luteolin was 0.015 and 0.025 mg g⁻¹ respectively.     

Inhibition of Penicillium expansum by an oxidative treatment

Several oxidizing compounds such as sodium hypochlorite (NaClO) and hydrogen peroxide (H₂O₂) are used to control postharvest decay in fresh fruit due to their antimicrobial effects. Here, we applied these compounds in vitro, in the presence of CuSO₄, against Penicillium expansum, causal agent of apple blue mold. MICs were 50 mg L⁻¹ and 400 mmol L⁻¹ for NaClO and H₂O₂, respectively, when these compounds were individually applied to conidia suspensions during 2 min. A combined oxidative treatment (OT) consisting on an incubation with 1 mg L⁻¹ NaClO and 200 mmol L⁻¹ H₂O₂, in the presence of 6 mmol L⁻¹ CuSO₄, inhibited growth, conidial germination and fungal infectivity on apple. The fractional inhibitory concentration index for the interaction between NaClO and H₂O₂ in the OT was 0.52 indicating a synergistic effect of the oxidizing compounds. These results suggest that the OT could be an interesting alternative for apple diseases postharvest control.     

Chemical characterization of a traditional honey-based Sardinian product: Abbamele

The first chemical characterization of abbamele, a traditional honey decoction from Sardinia (Italy) is hereby reported. Water content (from 17.7% to 27.7%), electrical conductivity (from 0.19 to 0.81 mS cm⁻¹), pH (from 3.21 to 3.92), free acidity (from 26.1 to 87.6 meq kg⁻¹), invertase activity (from 0 to 1.02 U kg⁻¹), 5-(hydroxymethyl)-2-furaldehyde, HMF (from 881 to 4776 mg kg⁻¹), total polyphenols (from 188 to 984 mg kg⁻¹) and free amino acid contents of thirteen abbamele samples, from industrial and traditional producers, were obtained in an attempt to compare this traditional product with honey and to study the relationship between its main features and the production procedures. The long thermal treatment involved in the production of abbamele has been identified as the main cause of very low (or absent) invertase activity and free amino acid content as well as the very high content of HMF.     

Comparison of free amino acid,carbohydrates concentrations in Korean edible and medicinal mushrooms

Ten popular species of both edible and medicinal Korean mushrooms were analysed for their free amino acids and disaccharides. The average total free amino acid concentration was 120.79 mg g⁻¹ in edible mushrooms and 61.47 mg g⁻¹ in medicinal mushrooms, respectively. The average total of free amino acids for all mushrooms, edible mushrooms and medicinal mushrooms was 91.13 mg g⁻¹. Agaricus blazei (227.00 mg g⁻¹) showed the highest concentration of total free amino acids; on the other hand, Inonotus obliquus (2.00 mg g⁻¹) showed the lowest concentration among the 10 species of mushrooms. The average total carbohydrates concentration was 46.67 mg g⁻¹ in the 10 species of mushrooms, where the edible mushrooms contained 66.68 mg g⁻¹ and the medicinal mushrooms contained 26.65 mg g⁻¹. The carbohydrates constituents of the 10 mushroom species were mainly mannose (36.23%), glucose (34.70%), and xylose (16.83%).     

Use of Fourier transform infrared spectroscopy for rapid comparative analysis of Bacillus and Micrococcus isolates

The identification of foodborne microorganisms and their endospores in food products are important for food safety. The present work compares Bacillus (Bacillus licheniformis, Bacillus circulans and Bacillus subtilis) and Micrococcus (Micrococcus luteus) species with Fourier transform infrared (FTIR) spectroscopy. Our results show that there are several characteristic peaks belonging to both the Micrococcus and Bacillus species which can be used for the identification of these foodborne bacteria and their endospores. For Micrococcus species, a new band was observed at 1338 cm⁻¹ which may be due to acetate oxidation via the carboxylic acid cycle. The bands at 1313 cm⁻¹ and 1256 cm⁻¹ can be explained by an exopolymer formation and the other bands at 1074 cm⁻¹ and 550 cm⁻¹, may be due to the glycogen-like storage material in Micrococcus spp. There are also characteristic peaks at 993 cm⁻¹ and 801 cm⁻¹ for these bacterial species. Different Bacillus species also showed characteristic peaks at 1000–500 cm⁻¹ region. Dipicolinic acid (DPA) bands at ∼728 cm⁻¹ and ∼703 cm⁻¹ seen only in B. circulans were the marker of an endospore formation.     

The effect of diets supplemented with thyme essential oils and rosemary extract on the deterioration of farmed gilthead seabream (Sparus aurata) during storage on ice

The effect on quality were assessed for gilthead seabream fed five different diets: control (basal diet); BHT (basal diet with 200 mg kg⁻¹ of butylated hydroxytoluene); rosemary (basal diet with 600 mg kg⁻¹ of rosemary extract - Rosmarinus officinalis); carvacrol (basal diet with 500 mg kg⁻¹ of essential oil of Thymbra capitata, carvacrol chemotype); and thymol (basal diet with 500 mg g⁻¹ of essential oil of Thymus zygis, subspecies gracilis, thymol chemotype). After 18 weeks of experimentation, the animals were stored on ice at 4 °C for 0, 7, 14, and 21 days. Physical-chemical, microbiological and sensory analyses were carried out at each sampling point to determine the degree of deterioration in the gilthead seabream. Lower indices of oxidation were observed in animals who were administered feeds supplemented with BHT, carvacrol and (to a lesser degree) rosemary. Lower bacteria counts were observed for the BHT and thymol groups, in addition to a slower deterioration in terms of sensory perception. Accordingly, the addition of natural antioxidants to the diet may have an added effect on fish quality, delaying post mortem deterioration.     

Effectiveness of short exposures of propylene oxide alone and in combination with low pressure or carbon dioxide against Tribolium castaneum (Herbst) (Coleoptera: Tenebrionidae)

Toxicity of the fumigant propylene oxide (PPO) alone and in combination with low pressure (100 mm Hg) or 92% CO₂ to all life stages of Tribolium castaneum using short exposure times (4 and 8 h) at 30°C was studied. Results indicated that PPO was moderately toxic with Ct products ranging from 120 to 608 mg h/l required to obtain complete mortality of the different life stages. A marked difference in susceptibility between life stages was recorded. Eggs were the most sensitive with a LD₉₉ value of 30.1 mg/l for 4 h, whereas pupae were the most tolerant with a LD₉₉ value of 146.5 mg/l. It was shown that an increase in exposure time from 4 to 8 h resulted in 23%, 42%, 48% and 47% reductions of LD₉₉ values for eggs, larvae, pupae and adults, respectively.There was no or very limited mortality of all stages except the egg (53% to 62%), when exposed to either 100 mm Hg or 92% CO₂ for 4 h. However, when 100 mm Hg or 92% CO₂ were combined with PPO, the LD₅₀ and LD₉₉ values for PPO in all stages except the egg were significantly reduced. Combinations of PPO with 100 mm Hg or 92% CO₂ produced equal reductions in the LD₉₉ value from 146.5 to about 22 mg/l for the most tolerant pupal stage. Both combinations also produced significant reductions in the LD₉₉ values for larvae and adults (6.3- to 6.6-fold) compared with those exposed to PPO alone. These results indicated that 100 mm Hg and 92% CO₂ each had a synergistic effect on the toxicity of PPO to T. castaneum. The combination of PPO with vacuum or CO₂ can thus provide a potential alternative to methyl bromide.