In aroma analysis, strawberries have always been the favored fruit because of their relatively high content of typical and pleasant aroma constituents. Esters, aldehydes, alcohols and sulfur compounds have been found to be the main aroma components in strawberry. In recent years, two volatile compounds, 2,5-dimethyl-4-methoxy-3(2H)-furanone (DMF) and 2,5-dimethyl-4-hydroxy-3(2H)-furanone (DHF) were reported to contribute heavily to strawberry aroma. These two compounds have been found in all wild strawberries studied, but found only in few cultivated varieties. In this work, three kinds of cultivated strawberries were sampled and analyzed. The three strawberries all belong to the Camarosa variety. They came from different growing areas: Salinas (California), Orrville (Ohio), and Memphis (Tennessee). The volatile compounds of these three strawberries were separated by Gas Chromatography (GC), and identified by Mass Spectrometer Detector (MSD). Column and experimental conditions were optimized for this particular separation. Salinas, Orrville and Memphis strawberries have very similar aroma constituents, however, in slightly differing amounts. Several unique peaks were found in each strawberry, which may well account for the differences in the aroma qualities of the three. 2-Furaldehyde was found in both Memphis and Orrville strawberries, but not in Salinas. It is a key odor compound correlated with woody aroma and it has a low odor threshold value. These two properties make it contribute negatively to the pleasant aroma of Memphis and Orrville strawberries. A compound, 2-furanmethanol, was found only in Salinas strawberries. This compound has a faint burning aroma, however, its high odor threshold value offsets its potentially bad aroma. DMF was found in all three strawberries, but no DHF was detected in any of the three. We propose a possible explanation for the absence of DHF. Ethyl (methylthio) acetate, which is a sulfur-containing compound, was found in both Orrville and Salinas strawberries. This work is the first to report its presence in strawberries of any variety. An external standard method was employed to quantify seven main aroma components found in the strawberry extracts. Aroma values were introduced and then calculated together with sensory descriptions of these compounds. Salinas strawberry was found to have the best aroma quality of the three. These results indicate that the odors of strawberries of the same variety can be different when grown in different geographical areas. / Master of Science

Made available in DSpace on 2014-08-20T14:33:14Z (GMT). No. of bitstreams: 1 Dissertacao_Tatiane_Kuka_Valente_Gandra.pdf: 6435645 bytes, checksum: d575f0c3d4782ff59377ccfc558b3d8a (MD5) Previous issue date: 2011-02-23 / The strawberry crop presents great importance for the Horticulture sector of the Southern part of Rio Grande do Sul due to its high yield and economic income, once the fruit has guaranteed market and high marketable price. Hydroponic cultivation allows optimizing the greenhouse vertical area, leading to a higher yield, reduces the diseases occurrence and also makes easier crop management and, as a consequence, enhances farmer life quality. However, there are few studies on the adaptation of the crop to this cultivation system, especially focusing concentrations of the nutrient solution and, overall, plant densities. Aiming to study growth, yield and fruit quality of strawberry crop in hydroponics system, two trials were conducted in a plastic greenhouse at Universidade Federal de Pelotas , RS. NFT (nutrient film technique) hydroponic system was employed. It consists of cement tiles cultivation benches. The first trial aimed to study different ionic concentrations of the nutrient solution for cultivar Camarosa and was replicated in two consecutive years (2009/2010). The analyzed experimental factor was the nutrient solution electrical conductivity (EC) at four levels: 0.9, 1.5, 2.1, 2.7dS m-1 (2009) and five levels: 0.7, 1.2, 1.7, 2.2, 2.7 dS m-1 (2010). The second trial was conducted in order to verify the effect of different plant densities on cultivar Camino Real. The experimental factor was plant density at four levels: 15.0, 12.5, 10.7, and 9.3 plants m-2. Fresh and dry matter of leaves, crown, roots and fruit, leaf area, fruit number and average fruit weight were evaluated. Samples of fruits were analyzed regarding to total soluble solids content (TSS), titratable total acidity (TTA)  for both trials of 2010  concentrations of anthocyanins, L-ascorbic acid, total phenolics compounds and 12 antioxidant capacity only for EC trial in 2010. The obtained results of the first trial indicated that EC from 1.2 to 1.5dS m-1 promotes plant growth and fruit yield. Growth and yield decreased when EC is below or above these values. The fruits total soluble solids content, antocyanin and L-ascorbic acid concentrations were increased at 1.7dS m-1 EC. The concentration of total phenolic compounds was increased reducing the EC to 1.2dS m-1. While soluble solids, anthocyanin and L-ascorbic acid content, respectively, decreased by 17, 17 and 15%, fruit yield was increased by 52% and phenolic compounds concentration by 22 %, when the EC decreased from 1.7 to 1.2dS m-1.The average fruit weight was reduced with increasing EC in 2009 and it was not affected in 2010, as well as the acidity and the antioxidant capacity. We can conclude that nutrient solution from 1.2 to 1.5 dS m-1 EC can be used to achieve higher yieldy, without great losses in fruit quality of cultivar Camarosa grown in NFT hydroponic system. The results obtained from the second trial indicated that growth and yield of individual plants of strawberry cultivar Camino Real was not affect by increasing plant density in the rage from 9.3 to 15.0 plants m-2. Growth and yield per square meter, as well as chemical characteristics related to the organoleptic quality of fruits (TSS and TSS/TTA), present linear response to increasing plant density. We suggest the adoption of the plant density of 12.5 plants m-2, which provides high yield, with appropriate organoleptic characteristics of fruits, and reduction in the number of plants required in relation to 15.0 plants m-2 plant density. However, it is necessary to carry out additional studies on cultivar Camino Real in order to promote changes in the system and its management and check the economic feasibility of its cultivation in hydroponics. / A cultura do morangueiro possui grande importância para o setor hortigranjeiro da Região Sul do Rio Grande do Sul, pois permite atingir altas produtividades e alto rendimento econômico, uma vez que as frutas tem mercado garantido e um alto valor. O cultivo hidropônico permite a otimização do espaço vertical do ambiente protegido, resultando em maior produtividade, diminuindo a ocorrência de doenças e, ainda, facilitando os tratos culturais e beneficiando a qualidade de vida do agricultor. Porém, há poucos estudos sobre a adaptação da cultura a este tipo de sistema de produção, principalmente em se tratando de concentrações da solução nutritiva e, sobretudo, de densidades de plantio. Com o objetivo de se estudar o crescimento, a produtividade e a qualidade das frutas de morangueiro em sistema hidropônico, dois experimentos foram realizados em condições de estufa plástica, no Campus da Universidade Federal de Pelotas, RS. O sistema hidropônico empregado era do tipo NFT (técnica da lâmina de nutrientes), constituído de bancadas de cultivo construídas com telhas de fibrocimento. O primeiro experimento teve o objetivo de estudar diferentes concentrações iônicas da solução nutritiva para a cultivar Camarosa e foi repetido em dois anos consecutivos (2009/2010). O fator experimental estudado foi a condutividade elétrica da solução nutritiva (CE) em quatro níveis: 0,9; 1,5; 2,1; 2,7dS m-1 (2009); e cinco níveis: 0,7; 1,2; 1,7; 2,2 e 2,7 dS m-1 (2010). O segundo experimento foi conduzido a fim de verificar o efeito de 9 diferentes densidades de plantio sobre a cultivar Camino Real. O fator experimental estudado foi a densidade de plantio em quatro níveis: 15,0; 12,5; 10,7 e 9,3 plantas m-2. Avaliaram-se a matéria fresca e seca de folhas, coroa, raízes e frutas, a área foliar, o número de frutas e o peso médio das frutas. Amostras das frutas foram analisadas em relação ao teor de sólidos solúveis totais (SST), à acidez total titulável (ATT)  em ambos os experimentos realizados em 2010, às concentrações de antocianinas, ácido L-ascórbico, compostos fenólicos totais e à capacidade antioxidante  somente no experimento sobre CE, em 2010. Os resultados obtidos no primeiro experimento indicam que a CE entre 1,2 e 1,5dS m-1 favoreceu o crescimento da planta e a produtividade das frutas. O crescimento e a produtividade diminuíram quando a CE foi mantida abaixo ou acima destes valores. Os teores de SST, de antocianinas e de ácido L-ascórbico das frutas foram aumentados com a elevação da CE para 1,7dS m-1. A concentração de compostos fenólicos totais elevou-se com a diminuição da CE para 1,2dS m-1. Enquanto os teores de SST, de antocianinas e de ácido L-ascórbico, respectivamente, diminuíram em 17, 17 e 15%, a produtividade foi aumentada em 52% e a concentração de compostos fenólicos totais em 22%, quando a CE diminuiu de 1,7 para 1,2dS m-1. O peso médio das frutas foi reduzido com a elevação da CE em 2009 e não foi afetado em 2010, assim como a ATT e a capacidade antioxidante. Conclui-se que a solução nutritiva com CE entre 1,2 e 1,5dS m-1 pode ser indicada para obter maior produtividade, sem grandes perdas na qualidade das frutas da cultivar Camarosa em sistema hidropônico NFT. Os resultados obtidos no segundo experimento indicam que o crescimento e a produtividade individual das plantas da cultivar de morangueiro Camino Real não foram afetados pela elevação da densidade de plantio, no intervalo entre 9,3 e 15,0 plantas m-2. O crescimento e a produtividade por unidade de área, bem como as características químicas relacionadas à qualidade organoléptica das frutas (concentração de SST e relação SST/ATT), apresentaram resposta linear ao incremento da densidade de plantio. Sugere-se a adoção da densidade de plantio de 12,5 plantas m-2, que proporciona rendimento elevado e frutas com adequadas características organolépticas e redução no número de mudas necessárias, em relação à densidade de 15,0 plantas m-2. Porém, existe a necessidade de desenvolver novos estudos com a cultivar Camino Real, a fim de promover adaptações no sistema e seu manejo e verificar a viabilidade econômica de seu cultivo em hidroponia.