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Publication
Otimização da germinação de leguminosas com vista à melhoria da composição nutricional e da segurança microbiológica
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Authors
Abstract(s)
A germinação de leguminosas em ambiente doméstico tem vindo a ganhar popularidade devido
à perceção de que é uma prática simples e acessível que pode aprimorar a qualidade nutricional
do alimento a germinar. Contudo, as leguminosas germinadas podem acarretar elevados riscos
microbiológicos cuja magnitude poderá não ser conhecida pelo público interessado. O presente
trabalho de investigação teve como objetivo determinar se a germinação, praticada sob
diferentes condições de tempo e temperatura, pode aprimorar a qualidade proteica de
leguminosas e produzir rebentos com qualidade higiénica e microbiológica aceitáveis.
Sementes de leguminosas orgânicas foram adquiridas em lojas comerciais, lavadas, demolhadas
e germinadas durante 24 e 48 horas a 18ºC ou 25ºC sob condições controladas. Um tratamento
térmico de 80ºC/20s foi aplicado aos rebentos. Para analisar a qualidade microbiológica, foram
contados microrganismos aeróbios mesófilos, Enterobacterieaceae, Escherichia coli e fungos,
conforme os respetivos métodos (Normas ISO), nas sementes demolhadas e nos rebentos, e
pesquisas de Salmonella spp. e Listeria monocytogenes, pelo método VIDAS®, nos rebentos
prontos a consumir. Para avaliar a qualidade proteica, foi realizada a quantificação de
aminoácidos totais por UPLC-DAD e da proteína total, das sementes secas e dos rebentos, pelo
método de Kjedahl. Foram observados níveis Não Satisfatórios de microrganismos aeróbios
mesófilos e Enterobacteriaceae na maioria das amostras germinadas. As leveduras estiveram
presentes em níveis aceitáveis e os bolores foram somente contados em duas amostras
germinadas, também em níveis aceitáveis. Não foram contadas colónias de E. coli (<10 ufc/g)
e não foram detetadas as presenças de Salmonella spp. e Listeria monocytogenes em nenhuma
das amostras. O tratamento térmico estudado não provou ser eficaz na redução da contaminação
de microrganismos aeróbios mesófilos e Enterobacteriaceae até níveis aceitáveis para a maioria
das amostras. A germinação de leguminosas não demonstrou aprimorar a qualidade proteica
das leguminosas estudadas. Sabendo que as sementes foram germinadas sob condições
controladas, é possível prever que a prática de germinação caseira, se realizada sem a adoção
de medidas higiénicas, pode levar à produção de rebentos com elevado risco microbiológico.
Germination of pulses within a domestic environment has been gaining popularity since it is marketed as a quick and simple practice that is claimed to improve pulse seed nutrition. Sprouted seeds can, however, harbor major microbiological risks that may be unknown to consumers who take an interest in practicing home sprouting. The aim of this study is to figure out whether germination performed under different conditions of time and temperature can improve seed protein quality and lead to the production of microbiologically safe and hygienic ready-to-eat legume sprouts. Organic pulses bought from retail stores were washed and soaked and allowed to germinate during 24 and 48 hours at 18ºC or 25ºC, under controlled conditions. A temperature treatment (80ºC, 20 seconds) was applied to the sprouts. Aerobic mesophilic, Enterobacteriaceae, Escherichia coli, yeasts and molds were quantified with conventional methods (ISO standards) in the soaked seeds and sprouts to evaluate microbiological quality. Salmonella spp. and Listeria monocytogenes were detected by the VIDAS ® method on ready to-eat sprouts. In order to evaluate samples’ protein quality, total amino acid quantification of seeds and sprouts was performed by UPLC-DAD analysis and protein concentration was obtained through the Kjedahl method. Aerobic mesophilic and Enterobacterieaceae were counted at unsatisfactory levels for most sprouted samples. Yeasts were present at acceptable levels for all samples and molds were only counted in two sprouted samples, also at acceptable levels. No E. coli were counted (<10 ufc/g), and no Salmonella spp. and Listeria monocytogenes were ever detected. The temperature treatment studied was not effective in reducing the contamination of CAM and Enterobacteriaceae to acceptable levels for most samples. Germination of pulses was not shown to improve protein quality in studied seeds. Considering that seeds were germinated under controlled conditions, we can predict that practicing germination in a domestic environment, without aseptic conditions or hygienic practices, instead of promoting healthy habits through nutritional value, could lead to the production of sprouts with high microbiological risk.
Germination of pulses within a domestic environment has been gaining popularity since it is marketed as a quick and simple practice that is claimed to improve pulse seed nutrition. Sprouted seeds can, however, harbor major microbiological risks that may be unknown to consumers who take an interest in practicing home sprouting. The aim of this study is to figure out whether germination performed under different conditions of time and temperature can improve seed protein quality and lead to the production of microbiologically safe and hygienic ready-to-eat legume sprouts. Organic pulses bought from retail stores were washed and soaked and allowed to germinate during 24 and 48 hours at 18ºC or 25ºC, under controlled conditions. A temperature treatment (80ºC, 20 seconds) was applied to the sprouts. Aerobic mesophilic, Enterobacteriaceae, Escherichia coli, yeasts and molds were quantified with conventional methods (ISO standards) in the soaked seeds and sprouts to evaluate microbiological quality. Salmonella spp. and Listeria monocytogenes were detected by the VIDAS ® method on ready to-eat sprouts. In order to evaluate samples’ protein quality, total amino acid quantification of seeds and sprouts was performed by UPLC-DAD analysis and protein concentration was obtained through the Kjedahl method. Aerobic mesophilic and Enterobacterieaceae were counted at unsatisfactory levels for most sprouted samples. Yeasts were present at acceptable levels for all samples and molds were only counted in two sprouted samples, also at acceptable levels. No E. coli were counted (<10 ufc/g), and no Salmonella spp. and Listeria monocytogenes were ever detected. The temperature treatment studied was not effective in reducing the contamination of CAM and Enterobacteriaceae to acceptable levels for most samples. Germination of pulses was not shown to improve protein quality in studied seeds. Considering that seeds were germinated under controlled conditions, we can predict that practicing germination in a domestic environment, without aseptic conditions or hygienic practices, instead of promoting healthy habits through nutritional value, could lead to the production of sprouts with high microbiological risk.
Description
Tese de mestrado, Qualidade Alimentar e Saúde, 2023, Universidade de Lisboa, Faculdade de Farmácia.
Keywords
Leguminosas Germinação Qualidade microbiológica Perfil de aminoácidos Qualidade proteica Teses de mestrado - 2023