Use of nootkatone as a senescence indicator for Rouge La Toma Cv. grapefruit (Citrus paradisi Macf.)

The objective of this research was to study the usefulness of nootkatone as a senescence indicator for Rouge La Toma cv. grapefruit (Citrus paradisi Macf.), simulating different treatments that included the normal postharvest handling of citrus fruits: temperature conditioning, cold storage, shipment periods to overseas markets such as Japan and the U.S., marketing conditions, and storage at nonchilling temperature (control treatments). The highest nootkatone levels, determined by GLC-MS analyses, were detected in fruits subjected to control treatments. No significant differences were observed in nootkatone levels between treatments either with or without temperature conditioning prior to the start of the cold storage. Levels of nootkatone increased throughout time for all assayed treatments. The linear regressions of nootkatone levels showed correlation coefficients of 0.80 and 0.83 with storage time (29 and 42 days, respectively). Therefore, nootkatone appears to be a good indicator of senescence for Rouge La Toma grapefruit.     

Aroma-active components of nonfat dry milk.

Application of aroma extract dilution analysis (AEDA) on the volatile components of low-, medium-, and high-heat-treated nonfat dry milks (NDM) revealed aroma-active compounds in the log(3) flavor dilution (log(3) FD) factor range of 1 to 6. The following compounds contributed the highest log(3) FD factors to overall NDM flavor: 2,5-dimethyl-4-hydroxy-3(2H)-furanone [(Furaneol), burnt sugar-like]; butanoic acid (rancid); 3-(methylthio)propanal [(methional), boiled potato-like]; o-aminoacetophenone (grape-like); delta-decalactone (sweet); (E)-4,5-epoxy-(E)-2-decenal (metallic); pentanoic acid (sweaty); 4,5-dimethyl-3-hydroxy-2(5H)-furanone [(sotolon), curry]; 3-methoxy-4-hydroxybenzaldehyde [(vanillin), vanilla]; 2-acetyl-1-pyrroline and 2-acetyl-2-thiazoline (popcorn-like); hexanoic acid (vinegar-like); phenylacetic acid (rose-like); octanoic acid (waxy); nonanal (fatty); and 1-octen-3-one (mushroom-like). The odor intensities of Furaneol, butanoic acid, methional, o-aminoacetophenone, sotolon, vanillin, (E)-4,5-epoxy-(E)-2-decenal, and phenylacetic acid were higher in high-heat-treated samples than others. However, the odor intensities of lactones, 2-acetyl-1-pyrroline, and 2-acetyl-2-thiazoline were not affected by heat treatment. Sensory evaluation results also revealed that heat-generated flavors have a major impact on the flavor profile of NDM.     

Optimization of a pilot-scale process for producing lupin protein isolates with valuable technological properties and minimum thermal damage

This paper describes a pilot process for obtaining protein isolates from white lupin seed with improved water solubility and technofunctional properties as well as reduced thermal damage. After a careful optimization of the process parameters, two valuable food ingredients were prepared: lupin protein isolate type E, with a useful emulsifying capacity, and lupin protein isolate type F, with a high capability of foam formation and stabilization. The spray-drying process was particularly critical for inducing some thermal damage, but a careful selection of the conditions permitted ingredients having only marginally impaired lysine bioavailability to be obtained. The reproducibility of the protein extraction process was tested on two different lupin varieties.     

Occurrence of Polycyclic Musks in Sewage Sludge and their Behaviour in Soils and Plants. Part 1: Behaviour of Polycyclic Musks in Sewage Sludge of Different Treatment Plants in Summer and Winter (5 pp)

Background, Aim and Scope   Part 1: Behaviour of Polycyclic Musks in Sewage Sludge of Different Treatment Plants in Summer and Winter Part 2: Investigation of Polycyclic Musks in Soils and Plants -  Preamble. In Part 1 of the study, screening tests were performed to investigate the occurrence of PCMs in sewage sludges. For a preliminary risk assessment, further information is needed about their behaviour in the terrestrial environment. Hence, Part 2 examined the adsorption of PCMs to soil, their dissipation and leaching in soil and their uptake by plants. Background, Aim and Scope   Polycyclic Musks (PCMs) enter the environment via the waste water system. Because of their persistence, they can accumulate in different matrices like sewage sludge or biota. By the use of sewage sludge as a fertilizer, PCMs are transferred to agricultural soils. Therefore, in Part 1 of the study, screening tests were performed to investigate the occurrence of PCMs in sewage sludge. For a preliminary risk assessment, further information is needed about their behaviour in the terrestrial environment. Hence, Part 2 of the study examined the adsorption of PCMs to soil, their dissipation and leaching in soil, and their uptake by plants. Materials and Methods: In the screening study, samples of activated sewage sludge were taken both in summer and in winter at 21 treatment plants. In order to get an overview of the contamination situation, sampling covered different types of treatment plants (in rural, urban, industrial areas). Analytical methods for the determination of HHCB, AHTN, ADBI, ATTN, AHDI and ATII in the sludge samples were developed and applied. Results: The analytical screening of PCMs showed their presence in activated and dried sewage sludge samples. HHCB and AHTN represented about 95% of the PCMs investigated. Their concentrations in the activated sludge samples varied between 2.9 and 10.4 mg/kg dry mass (dm) and 1.1 to 4.2 mg/kg dm, respectively. Although different types of sewage treatment plants were investigated, similar PCM levels were found, showing the widespread input of these compounds into domestic waste water. Discussion: PCM concentrations in activated sludge varied widely. The variation drops substantially when concentrations are related to the varying dry mass. In dehydrated sludge, PCM concentrations were up to 24 mg/kg dm for HHCB and up to 6.9 mg/kg dm for AHTN. These high values are comparable to those obtained in other investigations analysing PCMs. If the degradation of organic mass during anaerobic decomposition is included in the evaluation, the figures obtained are comparable to those for activated sludge. Elimination in sewage sludge was higher in summer than in winter. Therefore, the contamination of the sludges in winter reached higher levels compared to the summer. Conclusions: The results show that PCMs are widespread contaminants in sewage sludge. Recommendations and Perspectives: PCM should be considered in a risk assessment as potential contaminants of sewage sludge destined for agricultural use. Due to the high PCM levels in sewage sludge, further investigations into the degradation and elimination behaviour in sewage sludge have to be carried out, including that involving PCM metabolites such as lactone derivatives.     

Effects of rhodium heterogeneous catalyst and isomerization conditions on linoleic acid conjugation of soybean oil

Rhodium heterogeneous catalyst was used to catalyze isomerization of linoleic acid in soybean oil to conjugated linoleic acid (CLA). A central composite rotatable design with five levels of three variables, namely, reaction temperature, stirring speed, and reaction time, was used to determine the maximum CLA yield. The formation of CLA during isomerization was greatly dependent on the reaction temperature and time. The CLA content of soybean oil increased from 0.63 to 202.42 mg/g oil when isomerization was done at 200 degrees C, with a stirring speed of 200 rpm for 49 min. Analysis of triacylglycerol positions showed that linoleic acid at any position in a triacylglyceride could possibly be isomerized to CLA.     

Influence of storage practices on acrylamide formation during potato frying

A number of parameters linked to storage of potatoes were evaluated with regard to their potential to influence the acrylamide formation in French fries. Acrylamide, which is a potential human carcinogen, is reported to be formed during the frying of potatoes as a result of the reactions between asparagine and reducing sugars. This study was conducted using three potato varieties (Bintje, Ramos, and Saturna) typically used in Belgium, The Netherlands, and the northern part of France for French fry and crisp production. Saturna, mainly used in crisp production, appeared to be the least susceptible for acrylamide formation during frying. Especially storage at low temperatures (4 degrees C) compared to storage at 8 degrees C seemed to enhance acrylamide formation due to a strong increase in reducing sugars caused by low-temperature storage. Because of the reversible nature of this physiological reaction, it was possible to achieve a significant reduction of the reducing sugars after a reconditioning of the cold-stored potatoes for 3 weeks at 15 degrees C. All changes in acrylamide concentrations could mainly be explained by the reducing sugar content of the potato (R2 = 0.84, n = 160). This means that, by ensuring a low reducing sugar content of the potato tuber, the risk for acrylamide formation will largely be reduced. Finally the use of a sprout inhibitor did not influence the composition of the potato, and thus acrylamide formation was not susceptible to this treatment.     

Investigations on the Behaviour of Fenpropimorph and its Metabolite Fenpropimorphic Acid in Soils

The fate of fenpropimorph and its metabolite fenpropimorphic acid was investigated in a silty sand soil and in a clayey silt soil. In laboratory and field experiments fenpropimorph disappeared without a lag phase. A few days after application fenpropimorphic acid was detected. Additional laboratory experiments with [¹⁴C]fenpropimorph emphasized the significance of mineralization and the formation of non-extractable residues. The determination of soil/water distribution coefficients of parent compound and metabolite yielded a higher leaching potential for fenpropimorphic acid due to its higher polarity. This was confirmed by performing a laboratory column test under worst-case conditions. Under field conditions, however, fenpropimorphic acid was detected only in the superficial soil layers (0–5 cm) of both investigation sites at very low concentrations.     

Interactions of local habitat type,landscape composition and flower availability moderate wild bee communities

Context

Landscape and local habitat traits moderate wild bee communities. However, whether landscape effects differ between local habitat types is largely unknown.

Objectives

We explored the way that wild bee communities in three distinct habitats are shaped by landscape composition and the availability of flowering plants by evaluating divergences in response patterns between habitats.

Methods

In a large-scale monitoring project across 20 research areas, wild bee data were collected on three habitats: near-natural grassland, established flower plantings and residual habitats (e.g. field margins). Additionally, landscape composition was mapped around the research areas.

Results

Our monitoring produced a dataset of 27,650 bees belonging to 324 species. Bee communities on all three habitats reacted similarly to local flower availability. Intensively managed grassland in the surrounding landscape had an overall negative effect on the studied habitats. Other landscape variables produced diverging response patterns that were particularly pronounced during early and late season. Bee communities in near-natural grassland showed a strong positive response to ruderal areas. Flower plantings and residual habitats such as field margins showed a pronounced positive response to extensively managed grassland and woodland edges. Response patterns regarding bee abundance were consistent with those found for species richness.

Conclusion

We advise the consideration of local habitat type and seasonality when assessing the effect of landscape context on bee communities. A reduction in the intensity of grassland management enhances bee diversity in a broad range of habitats. Moreover, wild bee communities are promoted by habitat types such as ruderal areas or woodland edges.

     

Genetic variation of seedling traits responded to brassinosteroid and gibberellin inhibitors in maize (Zea mays) doubled haploid lines

The purpose of this study was to examine the genotypic variation in maize doubled haploid (DH) lines response to brassinosteroid and gibberellin inhibitors. Plant responses to hormone inhibitors were determined in growth chamber experiments using germination paper for three different seedling treatments: application of propiconazole (Pcz), uniconazole (Ucz) or water (control). Mesocotyl length (ML) was more sensitive to hormone inhibitors, especially to the Ucz treatment, than other seedling traits. ML was significantly correlated with other traits in the Ucz treatment. All the seedling traits showed moderate-to-high broad sense heritability values, ranging from 0.39 to 0.82. The Euclidian genetic distances of inbred line pairs ranged from 1.27 to 19.94, indicating there was a high level of variability across the maize DH lines used in this study. DH lines with extreme MLs were identified, which can provide valuable breeding resources for improving abiotic stress tolerance, and for further genetic studies.     

Genome-wide in silico analysis of SOD genes in common bean (Phaseolus vulgaris L.)

Journal of Crop Science and Biotechnology - Superoxide dismutases (SODs) are a group of enzymes that play essential roles in catalyzing the dismutation of superoxide radicals to protect cells from...