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  • About
  • The Global ETD Search service is a free service for researchers to find electronic theses and dissertations. This service is provided by the Networked Digital Library of Theses and Dissertations.
    Our metadata is collected from universities around the world. If you manage a university/consortium/country archive and want to be added, details can be found on the NDLTD website.
1

DefiniÃÃo de marcadores quÃmicos por acompanhamento do processamento tÃrmico e ultrassom de ponteira de suco de maracujà / Definition of chemical markers by monitoring of thermal processing and ultrasoun probe of passion fruit juice.

MÃrcia ValÃria Lacerda Soares 24 February 2015 (has links)
Dentre as espÃcies existentes de maracujÃ, somente trÃs sÃo utilizadas pela indÃstria e, entre estas, exclusivamente a Passiflora edulis atende ao mercado de alimentos, pois alÃm desta espÃcie possuir atributos sensoriais bastante atrativos, ainda possui diversos benefÃcios para melhoria da saÃde. Entretanto, nem sempre as caracterÃsticas da fruta in natura sÃo mantidas apÃs serem processadas. Sendo assim, este estudo tem por objetivo avaliar o perfil de metabÃlitos presentes em suco de maracujà apÃs o tratamento tÃrmico de pasteurizaÃÃo e de esterilizaÃÃo em diferentes condiÃÃes de tempo e temperatura e ainda avaliar o efeito do tratamento tÃrmico no suco utilizando-se processamento com ultrassom. As variÃveis utilizadas no processamento tÃrmico foram tempo de retenÃÃo (0, 4, 15, 30 e 60 segundos), temperatura (85 e 140ÂC) e para o processo nÃo tÃrmico com ultrassom de ponteira foram variadas as potÃncias (50.000, 75.000 e 100.000 W/L) e o tempo (1; 2,5; e 5 min). Para extraÃÃo dos compostos utilizou-se metanol e foi feita a identificaÃÃo das amostras em UPLC-MS. TambÃm foram realizadas anÃlises de ressonÃncia magnÃtica (RMN) e PolifenÃis ExtraÃveis Totais (PET). Para o tratamento de dados foi feita anÃlise do componente principal (PCA) para o UPLC-MS e RMN. Os resultados foram comparados a uma amostra controle, tendo sido encontrados 27 picos, dos quais 4 foram degradados, 7 foram formados e 16 permaneceram inalterados para o tratamento tÃrmico e para o ultrassom de ponteira nÃo houve grandes variaÃÃes, quanto ao teor de polifenÃis, estes tornaram-se disponÃveis com aumento da temperatura, bem como com potÃncia mais alta por um tempo de 5 minutos. O processo tÃrmico pode ser controlado a partir de dados obtidos sobre o perfil de suco de maracujà submetido a tratamento tÃrmico. / Brazil has a great biodiversity, which should be explored and transformed into food and products to be consumed. Among existing species of passion fruit, only three are used by industry and among these, exclusively the Passiflora edulis serves the food market, because this species has very attractive sensory attributes,also is related to several benefits to improvhealth. However, the fruit characteristics âin naturaâ are not always maintainedthem after processing. Thus, this study aims to evaluate the metabolic profile present in passion fruit juice after heat treatment of sterilization further morepasteurization in different conditions of time and temperature and still submit the juice without heat treatment to a ultrasoundprocessing. The studied variables in heat processing wereretentiontime (0, 4, 15, 30 and 60 seconds), temperature (85 and 140 ÂC) and the non-thermal ultrasound process withpower (50.000, 75.000 e 100.000 W/L) and time (1, 2.5 and 5 minutes). For the extraction of the compounds were used methanol, and sample identification performed in LC-MS. Also was carried out Nuclear Magnetic Resonance analysis (NMR) andTotal Extractable Polyphenols (TEP). In the methodology employed for processing with ultrasound, the samples were subjected to different power and time. Then, was performed the same reading and extracting methodology used for heat processing. For treatment of the data was performed Principal Component Analysis (PCA) for LC-MS and NMR, the polyphenols were analyzed by the method described by Singleton and Rossi (1965), with adaptations. The results were compared to a control sample (no treatment). Were found 32 chromatographic peaks, of which 4 were degraded, 12 were formed and 16 remained unchanged. With increasing temperature, there was degradation of phenolic compounds. The heat process can be controlled from data obtained on the passion fruit juice profile submitted to heat treatment.

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