No abstract

Pure polyethylene (PE) is enriched with several additives to make it a smart application material in protected cultivation, as a cover material for either greenhouses or screenhouses. When this material completely or partially absorbs ultraviolet (UV) solar radiation, then it is called UV blocking material. The current work presents a review on the effects of the UV blocking covering materials on crop growth and development. Despite the passage of several years and the evolution of the design technology of plastic greenhouse covers, UV blocking materials have not ceased to be a rather interesting technique for the protection of several vegetable and ornamental species. Much of the research on UV blocking materials focuses on their indisputable effect on reducing the activity of pests and viral-related diseases, rather than on the effects on the crop physiology itself. In the present paper, representative studies dealing with the effect of the UV blocking materials on the agronomic factors of different crops are presented and discussed. The results reveal that UV blocking materials have mainly positive effects on the different plant physiological functions, such as photosynthesis and transpiration rate, and on growth characteristics, while they might have a negative effect on the production and content of secondary compounds, as anthocyanins and total phenolics.

The effect of blocking the ultraviolet (UV) solar radiation using a UV-absorbing low density polyethylene (PE) film on tomato crop yield and fruit quality was evaluated in a two-year study in two arched roof greenhouses located in Central Greece. The UV-A and UV-B radiation transmission values of the greenhouse covered by the UVabsorbing PE film during the first year were 0.4% and 1.2%, respectively and increased to 0.8% and 1.3% in the 2 nd year, while the respective values in the greenhouse covered by a traditional PE film were 20.7% and 12.5% during the 1 st year and 28.7% and 26.7% during the 2 nd year. Under the UV-absorbing film the number of insect injured fruit was reduced and the marketable yield was similar or higher than that under the common PE film, while fruit quality characteristics (size, shape), nutritional value (ascorbic acid and lycopene) and organoleptic quality (pH, titratable acidity and total soluble solids) were similar under both covering materials. Moreover, the reduction of incoming UV radiation had an appreciable effect on fruit skin color, indicating an effect on pigments other than lycopene.Additional key words: fruit quality; insects; polyethylene; transmission; ultraviolet radiation; UV-stabilizers. ResumenEfectos sobre el rendimiento y la calidad del tomate de un film de cubierta de invernaderos absorbente de UV Se evaluó, en un estudio de dos años, en dos invernaderos a dos aguas ubicados en Grecia Central, el efecto del bloqueo de la radiación ultravioleta (UV) solar, utilizando un film absorbente de polietileno (PE) de baja densidad absorbente de UV, sobre el rendimiento del cultivo del tomate y la calidad del fruto. Los valores de transmisión de la radiación UV-A y UV-B del invernadero cubierto por el film PE absorbente de UV en el primer año fueron 0,4% y 1,2%, respectivamente, y se incrementaron hasta el 0,8% y el 1,3% en el segundo año. Estos valores en el invernadero cubierto por una película tradicional de PE fueron 20,7% y 12,5%, respectivamente, durante el 1 er año y 28,7% y 26,7% durante el segundo año. Bajo la película absorbente de UV se redujo el nú-mero de frutos con heridas producidas por insectos y el rendimiento comercializable fue similar o mayor que bajo la película de PE tradicional, mientras que las características de calidad del fruto (tamaño, forma), el valor nutricional (ácido ascórbico y licopeno) y la calidad organoléptica (pH, acidez titulable y sólidos solubles totales) fueron similares con ambos materiales de revestimiento. Por otra parte, la reducción de la radiación UV entrante tuvo un efecto apreciable en el color de la piel de fruta, lo que indica un efecto sobre otros pigmentos distintos del licopeno.Palabras clave adicionales: calidad de la

In this work, the production of a novel and sustainable silage was realized and optimized. Three agro-industrial wastes produced in bulk: olive mill wastewater (OMWW), grape pomace (GP) and de-proteinized feta cheese whey (DFCW) were mixed with coarsely ground maize grains, and the mixture was inoculated with commercial lactic bacteria starter culture and fermented for 30 days under anaerobic conditions to obtain silage. Sixty-seven recipes with varying compositions of the three agro-wastes were ensilaged, and four silage quality indices: pH value, % acidity as lactic acid, total lactobacillus count (cfu/g) and total yeast and mold count (cfu/g) were monitored throughout the ensilage process, and the obtained data were used to perform multicriteria optimization of the silage composition. The optimization target was to simultaneously maximize the pH drop, % total acidity as lactic acid and lactobacillus count while minimizing the count of undesirable yeasts and molds. Following this optimization strategy, it was found that the best composition of the mixture of all three tested agro-industrial wastes to obtain a high-quality silage was the one containing: 20% w/w GP, 60% w/w OMWW and 20% w/w feta cheese whey. Finally, the produced silage was tested in broilers’ nutrition and by 10% w/w inclusion in the feed, which led to the production of high added-value bioactive meat rich in ω-3 fatty acids and with high antioxidant capacity.

Orange pomace (OP) is a solid waste produced in bulk as a byproduct of the orange juice industry and accounts for approximately 50% of the quantity of the fruits processed into juice. In numerous literature references there is information about diverse uses of orange pomace for the production of high-added-value products including production of natural antioxidant and antimicrobial extracts rich in polyphenols and flavonoids which can substitute the hazardous chemical antioxidants/antimicrobials used in agro-food and cosmetics sectors. In this work and for the first time, according to our knowledge, the eco-friendly aqueous vacuum microwave assisted extraction of orange pomace was investigated and optimized at real industrial scale in order to produce aqueous antioxidant/antimicrobial extracts. A Response Surface Optimization methodology with a multipoint historical data experimental design was employed to obtain the optimal values of the process parameters in order to achieve the maximum rates of extraction of OP total polyphenols and/or total flavonoids for economically optimum production at industrial scale. The three factors used for the optimization were: (a) microwave power (b) water to raw pomace ratio and (c) extraction time. Moreover, the effectiveness and statistical soundness of the derived cubic polynomial predictive models were verified by ANOVA.