This page has only limited features, please log in for full access.
Light emitting diodes (LEDs) are an energy efficient alternative to high-pressure sodium (HPS) lighting in tomato cultivation. In the past years, we have learned a lot about the effect of red and blue LEDs on plant growth and yield of tomatoes. From previous studies, we know that plants absorb and utilize most of the visible spectrum for photosynthesis. This part of the spectrum is referred to as the photosynthetically active radiation (PAR). We designed a LED fixture with an emission spectrum that partially matches the range of 400 to 700 nm and thus partially covers the absorption spectrum of photosynthetic pigments in tomato leaves. Tomato plants grown under this fixture were significantly taller and produced a higher fruit yield (14%) than plants grown under HPS lighting. There was no difference in the number of leaves and trusses, leaf area, stem diameter, the electron transport rate, and the normalized difference vegetation index. Lycopene and lutein contents in tomatoes were 18% and 142% higher when they were exposed to the LED fixture. However, the ß-carotene content was not different between the light treatments. Transpiration rate under LED was significantly lower (40%), while the light use efficiency (LUE) was significantly higher (19%) compared to HPS lighting. These data show that an LED fixture with an emission spectrum covering the entire PAR range can improve LUE, yields, and content of secondary metabolites in tomatoes compared to HPS lighting.
Dennis Dannehl; Thomas Schwend; Daniel Veit; Uwe Schmidt. Increase of Yield, Lycopene, and Lutein Content in Tomatoes Grown Under Continuous PAR Spectrum LED Lighting. Frontiers in Plant Science 2021, 12, 1 .
AMA StyleDennis Dannehl, Thomas Schwend, Daniel Veit, Uwe Schmidt. Increase of Yield, Lycopene, and Lutein Content in Tomatoes Grown Under Continuous PAR Spectrum LED Lighting. Frontiers in Plant Science. 2021; 12 ():1.
Chicago/Turabian StyleDennis Dannehl; Thomas Schwend; Daniel Veit; Uwe Schmidt. 2021. "Increase of Yield, Lycopene, and Lutein Content in Tomatoes Grown Under Continuous PAR Spectrum LED Lighting." Frontiers in Plant Science 12, no. : 1.
Numerous investigations into the abiotic elicitation of plant responses with UV-B radiation, temperature, drought, CO2, nutrients, heavy metals and wounding have been carried out in the agronomic sector and are described in various reviews. However, it is not clear if electricity can be classified as an abiotic stress elicitor to affect plants. While the aforementioned abiotic stress elicitors are well investigated, the impact of electricity on plant development and accumulation of metabolites is not well understood. This review describes the effects of electricity, including strong and weak electric fields, magnetic fields and electric currents on plant growth and development, as well as on plant metabolites. Possible signalling pathways as affected by electricity are also discussed. It is further discussed the application of electricity to enhance plants in horticulture and it’s classification as an abiotic stress elicitor.
Dennis Dannehl. Effects of electricity on plant responses. Scientia Horticulturae 2018, 234, 382 -392.
AMA StyleDennis Dannehl. Effects of electricity on plant responses. Scientia Horticulturae. 2018; 234 ():382-392.
Chicago/Turabian StyleDennis Dannehl. 2018. "Effects of electricity on plant responses." Scientia Horticulturae 234, no. : 382-392.
Effects of organic waste from a hydroponic system added with minerals (organomineral fertilizer) and synthetic fertilizer on major polyphenols of red oak leaf lettuce using HPLC-DAD-ESI-MS3 were investigated. Interestingly, contents of the main flavonoid glycosides and caffeic acid derivatives of lettuce treated with organomineral fertilizer were equal to those synthesized without soil additives. This was found although soil nutrient concentrations, including that of nitrogen, were much lower without additives. However, lettuce treated with synthetic fertilizer showed a significant decrease in contents of caffeic acid derivatives and flavonoid glycosides up to 78.3 and 54.2%, respectively. It is assumed that a negative effect of a high yield on polyphenols as described in the growth-differentiation balance hypothesis can be counteracted by (i) a higher concentration of Mg or (ii) optimal physical properties of the soil structure. Finally, the organomineral substrate waste reused as fertilizer and soil improver resulted in the highest yield (+78.7%), a total fertilizer saving of 322 kg ha–1 and waste reduction in greenhouses.
Dennis Dannehl; Christine Becker; Johanna Suhl; Melanie Josuttis; Uwe Schmidt. Reuse of Organomineral Substrate Waste from Hydroponic Systems as Fertilizer in Open-Field Production Increases Yields, Flavonoid Glycosides, and Caffeic Acid Derivatives of Red Oak Leaf Lettuce (Lactuca sativa L.) Much More than Synthetic Fertilizer. Journal of Agricultural and Food Chemistry 2016, 64, 7068 -7075.
AMA StyleDennis Dannehl, Christine Becker, Johanna Suhl, Melanie Josuttis, Uwe Schmidt. Reuse of Organomineral Substrate Waste from Hydroponic Systems as Fertilizer in Open-Field Production Increases Yields, Flavonoid Glycosides, and Caffeic Acid Derivatives of Red Oak Leaf Lettuce (Lactuca sativa L.) Much More than Synthetic Fertilizer. Journal of Agricultural and Food Chemistry. 2016; 64 (38):7068-7075.
Chicago/Turabian StyleDennis Dannehl; Christine Becker; Johanna Suhl; Melanie Josuttis; Uwe Schmidt. 2016. "Reuse of Organomineral Substrate Waste from Hydroponic Systems as Fertilizer in Open-Field Production Increases Yields, Flavonoid Glycosides, and Caffeic Acid Derivatives of Red Oak Leaf Lettuce (Lactuca sativa L.) Much More than Synthetic Fertilizer." Journal of Agricultural and Food Chemistry 64, no. 38: 7068-7075.
Physical and chemical disinfection methods are used or are under investigation in greenhouse facilities to minimize the occurrence of pathogens and the application of pesticides in recirculating systems. Since the most of these methods differ in their effectiveness, more investigation is needed to produce healthy plants in a sustainable way. Therefore, the present study is focused on the identification of interactions between hypochlorite (ClO−) used as a disinfectant for a recirculating system and algae formation, spread of microorganisms, as well as plant development. As such, on-site produced potassium hypochlorite (1 % KClO) solution were supplemented using proportional injection control once a week for 90 min, as a disinfectant, into a recirculating tomato production system (NFT) until a free chlorine concentration of 1 mg L−1 (D I) and 2 mg L−1 (D II) were reached, respectively. The formation of the algae biofilm was reduced by 15 % (D I) and 48 % (D II). These treatments also suppressed cultivated microorganisms up to 100 %. Tomato plants exposed to the treatment D I showed a comparable plant height to the control plants after 7 weeks, whereas D II led to a significant increase in plant height of 12 cm. However, the formation of leaves was more pronounced by treatment D I. After a growing period of 7 weeks, a significant difference in leaf number up to 2.9 leaves per plant was calculated compared to the other treatments. The same treatment had the largest positively impact on the fruit yield and number of fruit, which were increased by 10 and 15 %, respectively, compared to the control plants. Under consideration of all results, the most promising effects of ClO− as a disinfectant for hydroponic systems were achieved with a free chlorine concentration of 1 mg L−1 (D I), where phytotoxic effects can be excluded.
Dennis Dannehl; Ingo Schuch; Yuan Gao; Sarah Cordiner; Uwe Schmidt. Hypochlorite Application for Controlling Algae Biofilm Formation, Microorganisms and Tomato Production in Recirculating Systems. Gesunde Pflanzen 2015, 67, 191 -199.
AMA StyleDennis Dannehl, Ingo Schuch, Yuan Gao, Sarah Cordiner, Uwe Schmidt. Hypochlorite Application for Controlling Algae Biofilm Formation, Microorganisms and Tomato Production in Recirculating Systems. Gesunde Pflanzen. 2015; 67 (4):191-199.
Chicago/Turabian StyleDennis Dannehl; Ingo Schuch; Yuan Gao; Sarah Cordiner; Uwe Schmidt. 2015. "Hypochlorite Application for Controlling Algae Biofilm Formation, Microorganisms and Tomato Production in Recirculating Systems." Gesunde Pflanzen 67, no. 4: 191-199.
Recently, official food surveillance discovered high residues of chlorate (ClO3 −) and perchlorate (ClO4 −) in different plant-based foods, which was the start of a big discussion in the EU Commission. There is currently no knowledge about possible ClO3 − uptake quantities in vegetable, when hypochlorite (ClO−) is used as a disinfectant in plant production facilities. Therefore, the present study is focused on the identification of interactions between ClO− applications and ClO3 − accumulations in fruit, as well as findings in terms of suitable concentrations of ClO− to ensure food safety. Primary and secondary metabolites were analyzed as well. As such, on-site produced potassium hypochlorite (1 % KClO) solution was supplemented using proportional injection control once a week for 90 min, as a disinfectant, into a recirculating tomato production system (NFT) until a free chlorine concentration of 1 mg L−1 (D I) and 2 mg L−1 (D II) was reached, respectively. The chlorate (ClO3 −) content in fruit increased from 0.01 mg (Control) to 0.22 mg (D I) and 0.25 mg ClO3 − kg−1 FW (D II). A critical assessment of these values is given in the discussion section. Contrary to the expectations, a co-occurrence of ClO3 − and ClO4 − in fruit was not found. Compared to the control, the fruit contents of lycopene were increased by 21.3 % (D I) and 33.5 % (D II) and those of ß-carotene by 9.2 % (D I) and 23.9 % (D II), when calculated on a fresh weight basis. These results changed slightly when these substances were calculated on a dry weight basis. Furthermore, ClO3 − induced stress in fruit. In this context, a significant correlation (r) and a significantly increased slope (m) compared to zero were found between ClO3 − and lycopene (r = 0.74; m = 0.10), as well as ß-carotene (r = 0.70; m = 0.01). The content of soluble solids and that of titratable acids remained unaffected.
Dennis Dannehl; Ingo Schuch; Yuan Gao; Sarah Cordiner; Uwe Schmidt. Effects of hypochlorite as a disinfectant for hydroponic systems on accumulations of chlorate and phytochemical compounds in tomatoes. European Food Research and Technology 2015, 242, 345 -353.
AMA StyleDennis Dannehl, Ingo Schuch, Yuan Gao, Sarah Cordiner, Uwe Schmidt. Effects of hypochlorite as a disinfectant for hydroponic systems on accumulations of chlorate and phytochemical compounds in tomatoes. European Food Research and Technology. 2015; 242 (3):345-353.
Chicago/Turabian StyleDennis Dannehl; Ingo Schuch; Yuan Gao; Sarah Cordiner; Uwe Schmidt. 2015. "Effects of hypochlorite as a disinfectant for hydroponic systems on accumulations of chlorate and phytochemical compounds in tomatoes." European Food Research and Technology 242, no. 3: 345-353.
A semi-closed greenhouse was used for sustainable tomato production and to investigate the effects of the prevailing climate conditions within this greenhouse on different plant parameters of tomatoes. Compared to conventionally cultivated tomato plants, the leaf area index, the number of trusses and the yield of marketable fruit of tomato plants exposed to the microclimatic conditions in the semi-closed greenhouse were significantly increased by 21, 11 and 31.9 %, respectively. Furthermore, the application of this new technology led to a significant increase in contents of lycopene (by 30 %), ß-carotene (by 40 %), phenolic compounds (25 %), titratable acids (by 8 %) and soluble solids (by 15 %) in tomatoes during the summer period. These results were attributed to higher photosynthetic activities, which predominantly occurred in the greenhouse with the semi-closed operation mode. Furthermore, the new technology can be seen as new horticultural approach to reduce the yield of blossom-end rot fruit by 75.2 %. This quality improvement was caused by higher levels of relative humidity, where this humidity states were also responsible for a reduction in the annual plant transpiration rate by 10 %. Tomaten wurden in einem semi-geschlossenen Gewächshaus im Vergleich zu einem konventionellen Gewächshaus produziert und die Auswirkungen der vorherrschenden Klimabedingungen in den Gewächshäusern auf verschiedene Pflanzenparameter untersucht. Im Vergleich zu konventionell kultivierten Tomatenpflanzen waren der Blattflächenindex (um 21 %), die Anzahl der Rispen (um 11 %) und der Ertrag der vermarktungsfähigen Früchte (um 31.9 %) der Tomatenpflanzen, die den mikroklimatischen Bedingungen im semi-geschlossenen Gewächshaus ausgesetzt waren, signifikant erhöht. Darüber hinaus führte die Applikation dieser neuen Technologie in den Sommermonaten zu einer signifikanten Erhöhung der Gehalte von Lykopin (um 30 %), ß-Carotin (um 40 %), phenolischen Verbindungen (um 25 %), titrierbaren Säuren (um 8 %) und löslicher Trockensubstanz (um 15 %) in Tomaten. Diese Ergebnisse wurden auf höhere photosynthetische Aktivitäten zurückgeführt, die überwiegend im Gewächshaus mit semi-geschlossenem Betriebsmodus auftraten. Weiterhin kann die neue Technologie als gartenbaulicher Ansatz gesehen werden, um den Ertrag der mit Blütenendfäule befallenden Früchte um 75,2 % zu reduzieren. Diese Qualitätsverbesserung wurde durch das höhere Niveau der relativen Luftfeuchtigkeit hervorgerufen, wobei diese Feuchtezustände auch für die Reduzierung der jährlichen Transpirationsrate um 10 % verantwortlich war.
Dennis Dannehl; M. Josuttis; S. Huyskens-Keil; Christian Ulrichs; U. Schmidt. Comparison of Different Greenhouse Systems and Their Impacts on Plant Responses of Tomatoes. Gesunde Pflanzen 2014, 66, 111 -119.
AMA StyleDennis Dannehl, M. Josuttis, S. Huyskens-Keil, Christian Ulrichs, U. Schmidt. Comparison of Different Greenhouse Systems and Their Impacts on Plant Responses of Tomatoes. Gesunde Pflanzen. 2014; 66 (3):111-119.
Chicago/Turabian StyleDennis Dannehl; M. Josuttis; S. Huyskens-Keil; Christian Ulrichs; U. Schmidt. 2014. "Comparison of Different Greenhouse Systems and Their Impacts on Plant Responses of Tomatoes." Gesunde Pflanzen 66, no. 3: 111-119.
Hanno Bährs; Barbara Borczak; Maria Fiorenza Caboni; Natalia Campillo; Reinhold Carle; Shumon Chakrabarti; Dennis Dannehl; M Elena Díaz-Rubio; Alberto Fernández-Gutiérrez; Shmuel Galili; Ana Maria Gómez-Caravaca; Ran Hovav; Olga Jáuregui; Melanie Josuttis; Judith Kammerer; Dietmar Rolf Kammerer; Vassiliki G. Kontogianni; Rosa María Lamuela-Raventos; Pauline Laue; Matías Libuy; Miriam Martínez-Huélamo; Jara Pérez-Jiménez; Paola Quifer-Rada; Ramón Rodrigo; Giuseppe Ruberto; Leonardo Sabatino; Josline Y. Salib; Fulgencio Saura-Calixto; Andreas Schieber; Nadine Schulze-Kaysers; Monica Scordino; Antonio Segura-Carretero; Gajendra Shrestha; Elzbieta Sikora; Laura Siracusa; Larry L. St Clair; Christian E.W. Steinberg; Anna Vallverdú-Queralt; Vito Verardo; Pilar Viñas; Fabian Weber. Contributors. Polyphenols in Plants 2014, 1 .
AMA StyleHanno Bährs, Barbara Borczak, Maria Fiorenza Caboni, Natalia Campillo, Reinhold Carle, Shumon Chakrabarti, Dennis Dannehl, M Elena Díaz-Rubio, Alberto Fernández-Gutiérrez, Shmuel Galili, Ana Maria Gómez-Caravaca, Ran Hovav, Olga Jáuregui, Melanie Josuttis, Judith Kammerer, Dietmar Rolf Kammerer, Vassiliki G. Kontogianni, Rosa María Lamuela-Raventos, Pauline Laue, Matías Libuy, Miriam Martínez-Huélamo, Jara Pérez-Jiménez, Paola Quifer-Rada, Ramón Rodrigo, Giuseppe Ruberto, Leonardo Sabatino, Josline Y. Salib, Fulgencio Saura-Calixto, Andreas Schieber, Nadine Schulze-Kaysers, Monica Scordino, Antonio Segura-Carretero, Gajendra Shrestha, Elzbieta Sikora, Laura Siracusa, Larry L. St Clair, Christian E.W. Steinberg, Anna Vallverdú-Queralt, Vito Verardo, Pilar Viñas, Fabian Weber. Contributors. Polyphenols in Plants. 2014; ():1.
Chicago/Turabian StyleHanno Bährs; Barbara Borczak; Maria Fiorenza Caboni; Natalia Campillo; Reinhold Carle; Shumon Chakrabarti; Dennis Dannehl; M Elena Díaz-Rubio; Alberto Fernández-Gutiérrez; Shmuel Galili; Ana Maria Gómez-Caravaca; Ran Hovav; Olga Jáuregui; Melanie Josuttis; Judith Kammerer; Dietmar Rolf Kammerer; Vassiliki G. Kontogianni; Rosa María Lamuela-Raventos; Pauline Laue; Matías Libuy; Miriam Martínez-Huélamo; Jara Pérez-Jiménez; Paola Quifer-Rada; Ramón Rodrigo; Giuseppe Ruberto; Leonardo Sabatino; Josline Y. Salib; Fulgencio Saura-Calixto; Andreas Schieber; Nadine Schulze-Kaysers; Monica Scordino; Antonio Segura-Carretero; Gajendra Shrestha; Elzbieta Sikora; Laura Siracusa; Larry L. St Clair; Christian E.W. Steinberg; Anna Vallverdú-Queralt; Vito Verardo; Pilar Viñas; Fabian Weber. 2014. "Contributors." Polyphenols in Plants , no. : 1.
A semi-closed solar collector greenhouse was tested to evaluate the yield and the energy saving potential compared with a commercial greenhouse. As such, new algorithm for ventilation, carbon dioxide (CO2) enrichment, as well as for cooling and heating purposes initiated by a heat pump, cooling fins under the roof and a low temperature storage tank were developed. This cooling system showed that the collector greenhouse can be kept longer in the closed operation mode than a commercial one resulting in high levels of CO2 concentrations, relative humidity and temperatures. Based on these conditions, the photosynthesis and associated CO2 fixations within the plant population were promoted during the experiment, resulting in a yield increase by 32%. These results were realized, although the mean light interception by energy screens and finned tube heat exchangers was increased by 11% compared to the reference greenhouse. The energy use efficiency was improved by 103% when the collector greenhouse was considered as energy production facility. In this context, the energy saving per kilogram produced tomatoes in the collector greenhouse is equivalent to the combustion of high amounts of different fossil fuels, where the reduced CO2 emissions ranged between 2.32 kg and 4.18 kg CO2 per kg produced tomatoes. The generated total heat was composed of approximately one-third of the latent heat and over two-thirds of the sensible heat, where a maximum collector efficiency factor of 0.7 was achieved.
Dennis Dannehl; Ingo Schuch; Uwe Schmidt. Plant Production in Solar Collector Greenhouses - Influence on Yield, Energy Use Efficiency and Reduction in CO2 Emissions. Journal of Agricultural Science 2013, 5, 1 .
AMA StyleDennis Dannehl, Ingo Schuch, Uwe Schmidt. Plant Production in Solar Collector Greenhouses - Influence on Yield, Energy Use Efficiency and Reduction in CO2 Emissions. Journal of Agricultural Science. 2013; 5 (10):1.
Chicago/Turabian StyleDennis Dannehl; Ingo Schuch; Uwe Schmidt. 2013. "Plant Production in Solar Collector Greenhouses - Influence on Yield, Energy Use Efficiency and Reduction in CO2 Emissions." Journal of Agricultural Science 5, no. 10: 1.
Climate change will lead to an excessive change in climate conditions in greenhouses, particularly during the summer. Therefore, a new climate strategy for greenhouses was developed to avoid plant damages. In this context, interactions between changing microclimatic conditions depending on different climate strategies and plant growth, fruit yield as well as secondary plant compounds were investigated between 2008 and 2009. The results showed that a combined application of a high pressure fog system and CO2 enrichment can be applied to decrease the inside temperature and to increase the levels of relative humidity and CO2 concentrations at a high ambient temperature, accompanied by an increase in mean temperature. Such microclimate in the greenhouse were sufficient to accelerate plant growth, to increase dry matter in leaves, and to promote the formation of fruit set per truss in comparison to those grown under conventional climate conditions. Furthermore, the algorithm of the new climate strategy led to a maximum total yield increase by 20%, to a reduction of blossom-end rot in tomatoes and to a pronounced increase in fruit size during the spring experiments. The climate conditions caused by the new technology significantly promoted secondary metabolism, resulting in a maximum increase in contents of lycopene (by 49%), β-carotene (by 35%), and phenolic compounds (by 16%) as well as associated antioxidant activity in the water-insoluble (by 18.5%) and water-soluble (by 35.4%) fraction compared to the conventional treated plants. Therefore, the new climate strategy may be appropriate to increase the total yield and to improve the fruit quality as well as the health-promoting properties of tomatoes.
Dennis Dannehl; Christian Huber; Thorsten Rocksch; Susanne Huyskens-Keil; Uwe Schmidt. Interactions between changing climate conditions in a semi-closed greenhouse and plant development, fruit yield, and health-promoting plant compounds of tomatoes. Scientia Horticulturae 2012, 138, 235 -243.
AMA StyleDennis Dannehl, Christian Huber, Thorsten Rocksch, Susanne Huyskens-Keil, Uwe Schmidt. Interactions between changing climate conditions in a semi-closed greenhouse and plant development, fruit yield, and health-promoting plant compounds of tomatoes. Scientia Horticulturae. 2012; 138 ():235-243.
Chicago/Turabian StyleDennis Dannehl; Christian Huber; Thorsten Rocksch; Susanne Huyskens-Keil; Uwe Schmidt. 2012. "Interactions between changing climate conditions in a semi-closed greenhouse and plant development, fruit yield, and health-promoting plant compounds of tomatoes." Scientia Horticulturae 138, no. : 235-243.
The effects of direct-electric-current (DC) on secondary plant compounds and antioxidant activity in harvested tomato fruits were investigated. A new technology was developed to supply DC to the tomatoes. Different intensities of DC (100–500 mA) with varied application times (15–60 min) were applied during postharvest. Almost all DC treatments significantly affected the secondary metabolism, resulting in an accumulation of carotenoids, phenolic compounds, and antioxidant activity in tomatoes. In the present study, optimal DC treatments were found in order to obtain the highest content of all investigated secondary plant compounds. After an adaptation time (AT) of 2 h, the maximum contents of lycopene (122.4%), ß-carotene (140.4%), total phenol (120.0%), and antioxidant activity (126.5%) were attained with a DC treatment of 500 mA for 15 min. The results changed after an adaptation time of 24 h (AT 24 h), where the highest contents of lycopene (128.7%), ß-carotene (129.6%), total phenol (113.6%), and antioxidant activity (120.9%) were obtained using the same DC treatment (500 mA), but with an application time of 30 min. Therefore, the application of DC in harvested tomato fruits may be appropriate to improve the health-promoting properties of tomatoes.
Dennis Dannehl; Susanne Huyskens-Keil; Ines Eichholz; Christian Ulrichs; Uwe Schmidt. Effects of direct-electric-current on secondary plant compounds and antioxidant activity in harvested tomato fruits (Solanum lycopersicon L.). Food Chemistry 2010, 126, 157 -165.
AMA StyleDennis Dannehl, Susanne Huyskens-Keil, Ines Eichholz, Christian Ulrichs, Uwe Schmidt. Effects of direct-electric-current on secondary plant compounds and antioxidant activity in harvested tomato fruits (Solanum lycopersicon L.). Food Chemistry. 2010; 126 (1):157-165.
Chicago/Turabian StyleDennis Dannehl; Susanne Huyskens-Keil; Ines Eichholz; Christian Ulrichs; Uwe Schmidt. 2010. "Effects of direct-electric-current on secondary plant compounds and antioxidant activity in harvested tomato fruits (Solanum lycopersicon L.)." Food Chemistry 126, no. 1: 157-165.
Um die Qualitätsverluste erntefrischer Erdbeeren während der Lagerung zu reduzieren, wurden die Auswirkungen verschiedener Verpackungsmaterialien, unter Berücksichtigung der Lagerungsdauer und der Lagerungstemperatur (20°C mit 75% relative Luftfeuchte, 4°C mit 88% relative Luftfeuchte), untersucht. Verwendet wurden Erdbeerschalen (500 g), die sich in Form, Anordnung und Anzahl der Lüftungsöffnungen, Verschließbarkeit sowie durch den Werkstoff voneinander unterschieden. Es konnte festgestellt werden, dass durch eine Temperaturabsenkung auf 4°C die Qualität der Erdbeeren in allen Verpackungsvarianten länger erhalten blieb. Dennoch wirkten sich die verwendeten Verpackungen unterschiedlich auf die festgelegten Qualitätsparameter aus. Das Verpackungsmaterial aus Polypropylen, welches mit einem Deckel verschlossen und nur vereinzelt mit Lüftungsschlitzen ausgestattet war, erzielte die besten Ergebnisse. Unter anderem wurden die Transpirationsverluste stark reduziert und begünstigten dadurch den Erhalt der Fruchtfleischfestigkeit und die Farbstabilität der Früchte. Dagegen wurde der Frischezustand während der Lagerung durch Einfluss der Materialien aus Polyethylenterephthalat, Polyactid und Holzschliff reduziert. Der Qualitätsverlust war weniger von dem Werkstoff, sondern von der Anzahl der Lüftungslöcher abhängig. Die Ergebnisse belegen, dass mit steigender Anzahl der Lüftungslöcher die Transpirationsverluste anstiegen und die Festigkeit und Farbstabilität der Früchte abnahmen. In diesem Zusammenhang konnte keine starke Reduzierung des pathogenen Befalls in Abhängigkeit der Belüftungsschlitze beobachtet werden. Das heißt, die Frischeverluste der Erdbeeren waren im Verpackungsmaterial aus Polypropylen am geringsten, gefolgt von den Verpackungen aus Polyethylenterephthalat, Polyactid und Holzschliff. Darüber hinaus konnte festgestellt werden, dass sich die Verpackungsart und die Lüftungslöcher auf den Druckstellenanteil und den Zellsaftausfluss der Erdbeeren auswirkten. Die unebene Bodenoberfläche in den Materialien aus Polyethylenterephthalat und Polyactid erhöhte den punktuellen Druck auf die Beeren, der zu Druckstellen und Verletzungen der Fruchtoberfläche führte. Scharfkantige Lüftungsschlitze in Nähe der Bodenoberfläche dieser Varianten begünstigten die Verletzungen und den Zellsaftaustritt aus den Verpackungen. In order to reduce the loss of quality of freshly harvested strawberries during storage, the effects of different packaging materials were examined with regard to storage time and temperature regime (20°C with relative humidity 75%, 4°C with relative humidity 88%). Strawberry containers (500 g) were used differing in form, alignment and number of ventilation openings, top and material. It was found that a drop in temperature to 4°C preserved the quality of strawberries longer in all packaging variants. Nevertheless, the used packaging material had different effects on the quality parameters. The packaging material made of polypropylene, which was closed with a lid and was equipped only with little ventilation openings, yielded the best results, e. g. the transpiration losses were strongly reduced, thus favouring the preservation of pulp consistency and colour stability of the fruits. On the other hand, the fresh mass during storage was reduced by the materials polyethylenterephthalat, polyactid and groundwood. The quality loss was less dependent on the material, but more dependent on the number of ventilation openings. The results showed that with increasing numbers of ventilation openings the transpiration losses increased and the consistency and colour stability of the fruits decreased. In this context, a strong reduction of pathogenic infestation in relation to the ventilation openings could not be observed. As such, the loss of freshness was lowest with the packaging material of polypropylene, followed by the polyethylenterephthalat, polyactid and groundwood. Moreover, it was found that the kind of packaging material and the ventilation openings had an effect on the amount of pressure marks and the discharge of cell sap of the strawberries. The uneven ground surface of the materials made of polyethylenterephthalat and polyactid increased the punctual pressure on the strawberry fruits, which led to pressure marks and injuries of the fruit surface. Sharp-edged ventilation openings close to the ground surface of these variants favoured injuries and cell sap discharges of the packaging.
Dennis Dannehl; Susanne Huyskens-Keil; Uwe Schmidt. Untersuchungen zur Lagerung von Erdbeeren unter Berücksichtigung verschiedener Verpackungsmaterialien. Erwerbs-Obstbau 2008, 50, 49 -61.
AMA StyleDennis Dannehl, Susanne Huyskens-Keil, Uwe Schmidt. Untersuchungen zur Lagerung von Erdbeeren unter Berücksichtigung verschiedener Verpackungsmaterialien. Erwerbs-Obstbau. 2008; 50 (2):49-61.
Chicago/Turabian StyleDennis Dannehl; Susanne Huyskens-Keil; Uwe Schmidt. 2008. "Untersuchungen zur Lagerung von Erdbeeren unter Berücksichtigung verschiedener Verpackungsmaterialien." Erwerbs-Obstbau 50, no. 2: 49-61.