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Biofortificação Agronómica de Pera Rocha (Pyrus communis) em Cálcio e Implicações na Composição Físico-Química e Nutricional
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O cálcio, para além de desempenhar funções estruturais, actua ainda como mensageiro secundário no organismo humano. O défice deste elemento mineral no organismo humano, pode promover deformações e diminuição da densidade da massa óssea, afetando o crescimento e a capacidade de locomoção, ou promover a ocorrência de fraturas. Contudo, equacionando-se como medida preventiva para a saúde o enriquecimento deste elemento mineral nas partes edíveis das plantas, a biofortificação agronómica pode ser uma estratégia que visa aumentar a disponibilização de Ca para absorção pelo organismo. Neste enquadramento, o principal objetivo deste estudo consistiu no desenvolvimento de metodologias/tecnologias para a monitorização e obtenção de pera Rocha biofortificada em Ca, com vista à produção de polmes destinados à indústria baby-food. O itinerário de biofortificação, foi implementado em dois pomares da variedade pera Rocha, localizados na região Oeste de Portugal. No primeiro ano, procedeu-se à aplicação de 7 pulverizações foliares de Ca(NO3)2 (0,1; 0,3; 0,6 kg/ha) e CaCl2 (0,4; 0,8; 1,6; 4; 8 kg/ha). No segundo ano, mantiveram-se as 7 pulverizações, aplicando-se CaCl2 (4 e 8 kg/ha) e no terceiro efetuou-se um scale-up com o itinerário optimizado com as concentrações do ano anterior. Durante a pós-colheita, os frutos foram mantidos em câmaras de conservação, efectuando-se nos últimos dois anos a imersão de alguns dos mesmos numa solução de 1,3 % CaCl2. Análises de monitorização de aspetos edafoclimáticos, fisiológicos e de qualidade foram concretizados durante a pré e pós-colheita, a par da aferição dos índices de enriquecimento em Ca. O uso de pulverizações com CaCl2 comparativamente a Ca(NO3)2 foi justificado pela ausência de sinais de fitotoxicidade em folhas (equacionando parâmetros fotossintéticos e dados de NDVI) e frutos (nomeadamente nas fases inicias do seu desenvolvimento) pulverizados com CaCl2, a par de melhores resultados no incremento dos teores de Ca nos frutos e folhas pulverizados. O itinerário optimizado consistiu em 3 aplicações de 4 kg/ha na fase inicial (após o vingamento do fruto), seguindo-se 4 aplicações com a concentração de 8 kg/ha. Este levou a incrementos das concentrações de Ca em todos os frutos pulverizados de ambos os pomares (em pelo menos 37,5% e 19,0% aquando da caracterização parcial e total respetivamente). O Ca distribuiu-se de forma heterogénea no fruto devido ao transporte deste elemento mineral através do xilema e das pulverizações foliares incidentes directamente nos frutos. Na pós-colheita, a imersão de frutos em 1,3 % de CaCl2 para favorecer a distribuição de Ca nos tecidos internos não foi conclusiva. Reportaram-se interacções com outros elementos (apenas antagonista no caso de K). Apesar das oscilações detectadas nalguns parâmetros físicos, químicos e nutricionais dos frutos, não se identificaram impactos negativos relacionados directamente com as pulverizações com Ca. A nível organolético, não se identificaram parâmetros dissuasores para o consumo de frutos biofortificados e polmes deles resultantes. Em conclusão, embora a fertilização foliar da pera Rocha possa ser condicionada pelas condições edafoclimáticas, o itinerário que se optimizou neste estudo permite o incremento da concentração de Ca nos frutos, muito embora com uma distribuição heterogénea, persistindo padrões de qualidade no respectivo consumo.
Besides performing structural functions, calcium also acts as a secondary messenger in the human body. Deficiency of this mineral element in the human body can promote deformation and decrease the density of bone mass, affecting growth and locomotion capacity, or promote the occurrence of fractures. However, considering as a preventive measure for health the enrichment of this mineral element in the edible parts of plants, agronomic biofortification can be a strategy that aims to increase the availability of Ca for absorption by the body. In this framework, the main objective of this study was to develop methodologies/technologies for monitoring and obtaining Rocha pear fruits biofortified in Ca, and further aiming to produce purées for the baby-food industry. The biofortification workflow was implemented in two Rocha pear orchards, located in the western region of Portugal. In the first year, 7 foliar sprays of Ca(NO3)2 (0.1; 0.3; 0.6 kg/ha) and CaCl2 (0.4; 0.8; 1.6; 4; 8 kg/ha) were performed. In the second year, the 7 sprays were maintained, applying CaCl2 (4 and 8 kg/ha) and in the third year, a scale-up was carried out with the optimized itinerary with the concentrations of the previous year. During post-harvest, the fruits were kept in storage chambers, and in the last two years, some fruits were immersed in a solution of 1.3 % CaCl2. Monitoring analysis of edaphoclimatic, physiological and quality aspects were carried out during pre- and post-harvest, along with the measurement of Ca enrichment indices. The use of sprays with CaCl2 compared to Ca(NO3)2 was justified by the absence of phytotoxicity signs in leaves (using photosynthetic parameters and NDVI data) and fruits (especially in the early stages of their development) sprayed with CaCl2, along with better results in increasing the Ca contents in sprayed fruits and leaves. The optimized workflow consisted of 3 applications of 4 kg/ha in the initial phase (after fruit setting), followed by 4 applications with the concentration of 8 kg/ha. This led to increases in Ca concentrations in all sprayed fruits from both orchards (by at least 37.5% and 19.0% when characterizing partially and fully respectively). Calcium was heterogeneously distributed in the fruit, due to the transport of this mineral element through the xylem and the foliar spraying directly on the fruit. At postharvest, the immersion of fruits in 1.3 % CaCl2 to favor Ca distribution in the internal tissues of fruits was not conclusive. Interactions with other elements were reported (only antagonistic in the case of K). Despite the oscillations detected in some physical, chemical and nutritional parameters of the fruits, no negative impacts directly related to Ca sprays were identified. At the organoleptic level, no dissuasive parameters were identified for the consumption of biofortified fruits and resulting purees. In conclusion, although the foliar fertilization of Rocha pear may be conditioned by edaphoclimatic conditions, the workflow that was optimized in this study allows the increase of Ca concentration in the fruits, although with a heterogeneous distribution, persisting quality standards in their consumption.
Besides performing structural functions, calcium also acts as a secondary messenger in the human body. Deficiency of this mineral element in the human body can promote deformation and decrease the density of bone mass, affecting growth and locomotion capacity, or promote the occurrence of fractures. However, considering as a preventive measure for health the enrichment of this mineral element in the edible parts of plants, agronomic biofortification can be a strategy that aims to increase the availability of Ca for absorption by the body. In this framework, the main objective of this study was to develop methodologies/technologies for monitoring and obtaining Rocha pear fruits biofortified in Ca, and further aiming to produce purées for the baby-food industry. The biofortification workflow was implemented in two Rocha pear orchards, located in the western region of Portugal. In the first year, 7 foliar sprays of Ca(NO3)2 (0.1; 0.3; 0.6 kg/ha) and CaCl2 (0.4; 0.8; 1.6; 4; 8 kg/ha) were performed. In the second year, the 7 sprays were maintained, applying CaCl2 (4 and 8 kg/ha) and in the third year, a scale-up was carried out with the optimized itinerary with the concentrations of the previous year. During post-harvest, the fruits were kept in storage chambers, and in the last two years, some fruits were immersed in a solution of 1.3 % CaCl2. Monitoring analysis of edaphoclimatic, physiological and quality aspects were carried out during pre- and post-harvest, along with the measurement of Ca enrichment indices. The use of sprays with CaCl2 compared to Ca(NO3)2 was justified by the absence of phytotoxicity signs in leaves (using photosynthetic parameters and NDVI data) and fruits (especially in the early stages of their development) sprayed with CaCl2, along with better results in increasing the Ca contents in sprayed fruits and leaves. The optimized workflow consisted of 3 applications of 4 kg/ha in the initial phase (after fruit setting), followed by 4 applications with the concentration of 8 kg/ha. This led to increases in Ca concentrations in all sprayed fruits from both orchards (by at least 37.5% and 19.0% when characterizing partially and fully respectively). Calcium was heterogeneously distributed in the fruit, due to the transport of this mineral element through the xylem and the foliar spraying directly on the fruit. At postharvest, the immersion of fruits in 1.3 % CaCl2 to favor Ca distribution in the internal tissues of fruits was not conclusive. Interactions with other elements were reported (only antagonistic in the case of K). Despite the oscillations detected in some physical, chemical and nutritional parameters of the fruits, no negative impacts directly related to Ca sprays were identified. At the organoleptic level, no dissuasive parameters were identified for the consumption of biofortified fruits and resulting purees. In conclusion, although the foliar fertilization of Rocha pear may be conditioned by edaphoclimatic conditions, the workflow that was optimized in this study allows the increase of Ca concentration in the fruits, although with a heterogeneous distribution, persisting quality standards in their consumption.
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Palavras-chave
Alimento funcional Biofortificação agronómica Cálcio Composição nutricional da pera Rocha Pyrus communis L. var. Rocha