Elke Pawelzik

Bee pollination improves crop quality, shelf life and commercial value

Pollination improves the yield of most crop species and contributes to one-third of global crop production, but comprehensive benefits including crop quality are still unknown. Hence, pollination is underestimated by international policies, which is particularly alarming in times of agricultural intensification and diminishing pollination services. In this study, exclusion experiments with strawberries showed bee pollination to improve fruit quality, quantity and market value compared with wind and self-pollination. Bee-pollinated fruits were heavier, had less malformations and reached higher commercial grades. They had increased redness and reduced sugar–acid–ratios and were firmer, thus improving the commercially important shelf life. Longer shelf life reduced fruit loss by at least 11%. This is accounting for 0.32 billion US

Nutrient contents, rumen protein degradability and antinutritional factors in some colour- and white-flowering cultivars of Vicia faba beans

of the 1.44 billion US

Influence of Various Nitrogen Applications on Protein and Amino Acid Profiles of Amaranth and Quinoa

provided by bee pollination to the total value of 2.90 billion US

Proteome analysis of Fusarium head blight in grains of naked barley (Hordeum vulgare subsp. nudum)

made with strawberry selling in the European Union 2009. The fruit quality and yield effects are driven by the pollination-mediated production of hormonal growth regulators, which occur in several pollination-dependent crops. Thus, our comprehensive findings should be transferable to a wide range of crops and demonstrate bee pollination to be a hitherto underestimated but vital and economically important determinant of fruit quality.

Effects of Fusarium Infection on the Phenolics in Emmer and Naked Barley

Six colour-flowering (Scirocco, Alfred, Carola, Condor, Tina and Herz Freya) and six white-flowering (Caspar, Albatros, Gloria, Tyrol, Vasco and Cresta) cultivars of Vicia faba were studied. The crude protein contents of colour- and white-flowering cultivars were 267 ± 13.6 and 283 ± 18.8 g kg -1 , respectively, which did not differ significantly at P Herz Freya > Carola. The CT were not detected in white-flowering varieties, T were virtually absent and TP were extremely low (40-49gkg -1 ). The activities of other antinutritional factors (white- and colour-flowering cultivars, respectively: trypsin inhibitor activity 3.05 ± 0.34 and 1.85 ± 0.09 mg trypsin inhibited g -1 ; lectin 27.2 ± 9.4 and 27.1 ± 5.I mg ml -1 assay medium producing haemagglutination; phytate 15.0+27 and 16.6 ± 2.3 g kg -1 ) were very low. A strong negative correlation (r = -0.92, P<0.001) between tannins and in vitro rumen protein degradability was observed which suggested that tannins have adverse effect on protein degradability. Similarly negative correlations between tannin levels and metabolisable energy (r = -0.89; P<0001) and organic matter digestibility (r = -089; P < 0.001) were observed. The correlation coefficient between trypsin inhibitor activity and tannins was negative and highly significant (r = -0.88, P < 0.001), whereas between tannins and saponins it was significantly positive (r = 096, P < 0001).

Importance of chlorogenic acid on the oxidative potential of potato tubers of two German cultivars

The effect of nitrogen application levels (0.16 and 0.24 g N kg(-1) soil) on seed proteins and their amino acid compositions of amaranth (Amaranthus spp.) and quinoa (Chenopodium quinoa Willd) was studied. Total proteins of amaranth and quinoa had high contents of lysine (6.3-8.2 g 100 g(-1) protein) but low contents of methionine (1.2-1.8 g 100 g(-1) protein). Seed proteins were fractionated on the basis of different solubility in water, saline, and buffer as albumin-1 (Albu-1), albumin-2 (Albu-2), globulin (Glob), and glutelin (Glu) and were identified by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Albu-1 was high in lysine (5.4-8.6 g 100 g(-1) protein), while Albu-2, which is a part of storage proteins, had a high leucine content (7.2-8.9 g 100 g(-1) protein) as an effect of different nitrogen application levels. Glu fractions were well-balanced in their essential amino acids with the exception of methionine. In conclusion, nitrogen application can be used for the nutritional improvement in human diet by increasing and maintaining protein and essential amino acid contents.

The effect of different factors on the content of nitrate in some potato varieties

The effect of artificial Fusarium graminearum and F. culmorum infection at the level of the proteome on grains of naked barley (Hordeum vulgare subsp. nudum) was investigated in comparison to naturally infected samples. Fusarium infection in barley led to numerous host‐specific biochemical responses. NEPHGE 2‐D PAGE and MS were used to identify proteins that were differentially expressed in response to fungal infection and growing location of the plants. Moreover, the mycotoxin concentration of the grains was evaluated to characterize the infection degree. Inoculation of naked barley with Fusarium led to grain deoxynivalenol concentrations of up to 1.2 mg/kg. The carbon and nitrogen grain concentrations were not significantly changed after fungal infection, but differed between growing locations. Eleven proteins related to fungal infection were detected as were three proteins with effects based on growing location. These proteins belong to different protein groups involved in various cell functions: transcription regulation, defence response, nutrient reservoirs and starch biosynthesis. The results gave indications on plant defence strategies and changes as response to Fusarium infection in mature grains after a long infection period as well as being influenced by the growing location.

Proteins of beer affect lipid levels in rats

Inoculated or non-inoculated naked barley and emmer cultivars were investigated with regard to their influence on phenolic acid profiles and their arabinoxylan content. Two groups of phenolic compounds were differentiated-methanol-soluble and hydrolyzable covalent-bound phenolic compounds. Chromatographic methods were applied for their analysis. The results showed ferulic acid as the predominant phenol in both total and covalent-bound fractions. The inoculation significantly reduced the ferulic acid content within a range of 5.6-6.6% in the two cereals and all their cultivars. Naked barley cultivars additionally contained the flavonoid catechin in the soluble fraction. The innoculation led here to a significant increase in the catechin content of about 4.5%. These results document an induction of the synthesis of catechin in naked barley after artificial Fusarium infection, whereas the ferulic acid content declined.

Identification of regulated proteins in naked barley grains (Hordeum vulgare nudum) after Fusarium graminearum infection at different grain ripening stages.

SummaryTwo German cultivars differing in blackspot susceptibility were grown in pots in 1998 and 1999 under control and water stress conditions. Blackspot susceptibility of the tubers was defined as oxidative potential. The effect of free tyrosine, cysteine, phenylalanine, chlorogenic and ascorbic acid on the oxidative potential was analyzed. A high concentration of ascorbic acid led to a decrease in the oxidative potential after harvesting in 1998. No correlation was found between oxidative potential and free tyrosine, phenylalanine or cysteine, respectively. Chlorogenic acid content increased during storage and gave a significant correlation with discoloration, showing that it can have an effect on the oxidative potential of the tuber greater than previously thought. Supplementing freeze-dried potato samples with pure chlorogenic acid increased the oxidative potential. Oxidative potential seems to depend on a series of chemical compounds, and their content is affected by factors including annual variations, cultivar, water availability and storage.

Sustainable Potato Production Worldwide: the Challenge to Assess Conventional and Organic Production Systems

SummaryThe ability for nitrate accumulation in potato tubers as affected by mineral fertilisation (N, K2O and MgO), genotype and the site of cultivation was studied in a three-year-long field experiment. Fertilisation with potassium chloride and potassium sulphate increased nitrate concentration in the tubers while additional magnesium fertilisation reduced nitrate concentration. Significant differences in nitrate concentrations were observed in potato tubers depending on genetic conditions as well as on the cultivation location (with the same soil and climatic conditions, varieties and tillage). The nitrate content decreased as the result of storage at 4 °C. Concentration of these ions in tubers of table and industrial potatoes did not exceed Acceptable Daily Intake level determined by WHO.