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Doctoral Thesis
DOI
10.11606/T.11.2007.tde-09052008-164854
Document
Author
Full name
Maria Carolina Dário Vitti
E-mail
Institute/School/College
Knowledge Area
Date of Defense
Published
Piracicaba, 2007
Supervisor
Committee
Kluge, Ricardo Alfredo (President)
Benedetti, Benedito Carlos
Durigan, Jose Fernando
Jacomino, Angelo Pedro
Moretti, Celso Luiz
Title in Portuguese
Respostas fisiológicas e bioquímicas de diferentes cultivares de batatas ao processamento mínimo
Keywords in Portuguese
Antioxidantes
Batata
Carboidratos
Enzimas
Fisiologia pós-colheita
Microbiologia de alimentos
Processamento de alimentos.
Abstract in Portuguese
O presente trabalho teve como objetivo avaliar aspectos fisiológicos e bioquímicos de batatas cv. Ágata, Asterix e Monalisa minimamente processadas. Primeiramente foram estudadas variáveis fisiológicas e microbiológicas de batatas armazenadas a 5, 15 e 25ºC. As batatas 'Asterix' apresentaram as maiores taxas respiratórias em relação a 'Ágata' e 'Monalisa', independente da temperatura de armazenamento. As contagens de bactérias psicrotróficas e coliformes totais, para todas as cultivares armazenadas a 5oC durante 9 dias de armazenamento, mantiveram-se dentro dos padrões aceitáveis. O armazenamento a 5oC foi eficiente no controle da atividade metabólica e na segurança de batatas minimamente processadas. No segundo experimento, o ensaio enzimático realizado teve como objetivo verificar o efeito de diferentes cultivares e de temperaturas de armazenamento (5 e 15ºC) sobre a atividade das enzimas fenilalanina amônia-liase (PAL), polifenoloxidase (PPO) e peroxidase (POD). As atividades enzimáticas aumentaram para todas as cultivares na temperatura de 15ºC. Batatas 'Ágata' e 'Asterix' são mais indicadas para processamento mínimo do que 'Monalisa', sendo esta mais susceptível ao escurecimento enzimático. O terceiro experimento avaliou os níveis de carboidratos não estruturais em batatas minimamente processadas e armazenadas a 5 e 15ºC. A maior degradação de amido em batatas 'Asterix' armazenadas a 5ºC esteve relacionada com o aumento do teor de açúcares solúveis verificado para este tratamento. Foi observado um aumento nos teores de amido para a cultivar 'Ágata' armazenada a 5ºC. Os teores de sacarose decresceram para todas as cultivares armazenadas a 5ºC e houve manutenção nos teores deste carboidrato quando armazenadas a 15ºC. No quarto experimento foram testadas diferentes combinações de antioxidantes nas três cultivares armazenadas a 5ºC. Batatas 'Monalisa' apresentaram os maiores teores de fenóis totais e valores de atividade da PAL, POD e PPO independente do tratamento. Batatas 'Ágata' tratadas com ácido ascórbico 2% + cisteína 0,5% e cisteína 0,5% + 4-hexilresorcinol 0,01% apresentaram os menores valores de atividade da PAL, POD e PPO. Para as cultivares Asterix e Monalisa os melhores resultados obtidos foram nas combinações com 4-hexilresorcinol e cisteína, respectivamente.
Title in English
Physiological and biochemical responses of different potato cultivars to minimal processing
Keywords in English
Antioxidants.
Browning
Carbohydrates
Enzymes
Microbiology
Minimally processed
Physiology
Solanum tuberosum L.
Abstract in English
The purpose of the present work was to evaluate physiological and biochemical aspects of minimally processed Agata, Asterix and Monalisa potato cultivars. First physiological and microbiological variables of fresh-cut potatoes stored at 5, 15 and 25ºC were evaluated. Potatoes 'Asterix' showed the highest respiratory rates when compared to potatoes cv. Agata and Monalisa, regardless of the storage temperature. Psychrotrophic bacteria and total coliforms counts were within acceptable limits for all cultivars stored at 5oC during 9 days of storage. Storage at 5oC was effective to control the metabolic activity and to keep food safety of minimally processed potatoes. In a second experiment, the effect of different cultivars and storage temperatures (5 and 15ºC) on the enzymatic activity of phenylalanine ammonia-lyase (PAL), polyphenol oxidase (PPO) and peroxidase (POD) was studied. Enzymatic activity increased in all cultivars at 15ºC. 'Agata' and 'Asterix' potatoes were more suitable for minimal processing than 'Monalisa'. This last cultivar is more susceptible to enzimatic browning. The third experiment was aimed at evaluating non-structural carbohydrates levels in mimally processed potatoes stored at 5 and 15ºC. The highest starch degradation rate was observed in potatoes 'Asterix' stored at 5ºC, which was related to the increase in the soluble sugar amount verified in this experiment. There was an increase in starch content in 'Agata' potatoes stored at 5ºC. Sucrose contents decreased in all cultivars stored at 5ºC and remained constant in cultivars stored at 15ºC. In a fourth experiment, different combinations of antioxidants in the three potato cultivars stored at 5ºC were studied. Potatoes 'Monalisa' showed the highest total phenol amounts and the highest activities of PAL, PPO and POD, regardless of treatment. 'Agata' potatoes treated with ascorbic acid 2% + cysteine 0.5% and cysteine 0.5% + 4-hexylresorcinol 0.01% showed the lowest valves activities of PAL, POD and PPO. For the Asterix and Monalisa cultivars, the best results were obtained when combinations of 4-hexylresorcinol and cysteine were used, respectively.
 
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Publishing Date
2008-05-15
 
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