La aplicación de campos magnéticos, parece producir modificaciones de algunos procesos fisiológicos de las plantas entre ellos estimular su desarrollo. Este estudio reporta el efecto de diferentes intensidades de campo electromagnético generadas por un solenoide con campo magnético horizontal variable sobre la germinación y el crecimiento de semillas de maíz. Se trabajó con semillas del híbrido experimental San José, las cuales se expusieron a un campo electromagnético de 0, 2, 4 y 6 mT, durante 3 min, bajo un diseño experimental completamente al azar en dos condiciones de semillas: imbibidas y sin embeber. Se realizó el análisis de varianza en las variables de germinación y crecimiento, con un nivel de significancia de 95%, y se observó un incremento en la germinación, el índice de vigor I, el índice de vigor II y la longitud de las raíces, de 3, 20, 34 y 23%, respectivamente, en comparación con las semillas testigo (sin tratar) al octavo día. De igual forma, se evaluó la presencia de pigmentos clorofílicos y carotenos, encontrándose un incremento en la concentración de clorofila a, clorofila b y carotenos en las plántulas de maíz obtenidas a partir de semillas tratadas electromagnéticamente. La respuesta varió en dependencia de la inducción magnética, sin ninguna tendencia particular; el mejor tratamiento fue el de 4µT, durante 3 min de exposición. El mejoramiento de las variables funcionales evaluadas sugiere que las semillas pueden funcionar mejor bajo la acción de un campo electromagnético

The application of magnetic fields appears to produce changes in some physiological processes of plants, including encouraging their development. This study reports the effects of different intensities of electromagnetic fields generated by a solenoid with a variable horizontal magnetic field on the germination and growth of maize seeds. We worked with the experimental seed hybrid San Jose, which was exposed to electromagnetic fields of 0, 2, 4 and 6 mT for 3 min, using a completely randomized design with two seed conditions: imbibed and non-imbibed. Analysis of variance was performed for the variables germination and growth, with a level of significance of 95%; increases were observed in germination, vigor index I, vigor index II and root length, 3, 20, 34 and 23% respectively, compared to the control seeds (untreated) on the eighth day. Similarly, the presence of chlorophyll pigments and carotenoids was assessed and an increase was found in the concentration of chlorophyll a, chlorophyll b and carotene in corn seedlings grown from electromagnetically treated seeds. The response varied depending on the magnetic induction, without any particular trend, the best treatment was 4 µT for 3 min of exposure. The improvement of the evaluated functional variables suggests that the seeds may perform better with an electromagnetic field treatment

O objetivo deste estudo foi avaliar a influência dos fatores embalagem e tempo na alteração da cor e degradação da clorofila, durante armazenamento de erva-mate tipo chimarrão em condições ambientais. Amostras de erva-mate, acondicionadas em embalagem de papel ou laminada, foram colocadas em câmara de armazenagem e analisadas em sete períodos, totalizando 12 semanas. Foram determinadas a concentração de clorofila (a, b e total), cor instrumental (CIELAB), umidade e atividade de água. Verificou-se degradação dos pigmentos clorofílicos nas amostras em embalagem laminada (redução de 59,5% na concentração de clorofila a e de 28,0% na de clorofila b) e resultados controversos para as amostras em embalagem de papel, os quais provavelmente tiveram interferência da reação de Maillard. As alterações de cor durante o período de armazenamento foram: redução no valor de L* para a erva-mate acondicionada em embalagem de papel (de 49,3 para 48,1) e aumento de L* para o produto em embalagem laminada (de 49,3 para 51,5); redução de -a* e redução de b* para o produto de ambas as embalagens, papel (a*=de -13,2 para -5,9; b*=de 29,3 para 28,5) e laminada (a*=de -13,3 para -7,0; b*=de 29,5 para 24,9). Concluiu-se que o tempo de armazenagem e o tipo de embalagem influenciaram significativamente (P<0,05) os itens analisados, e a alteração de cor foi provavelmente influenciada pelas reações de feofitinização e oxidação dos pigmentos clorofílicos da erva-mate.

The aim of this research was to evaluate the influence of packaging and time factors in color change and degradation of chlorophyll during storage of mate, mate type, in environmental conditions. Samples of mate, packaged in laminated flexible film or paper, were placed in a storage chamber, and analyzed at seven periods, during 12 weeks. Chlorophyll (a, b and total), instrumental color (CIELAB), moisture and water activity were determined. In the analysis of chlorophyllian pigments, it was verified their degradation in the samples packaged in laminated film (a reduction of 59.5% in chlorophyll a and 28.0% in chlorophyll b), and controversial results were found in the samples on paper package. This result probably suffered the interference of Maillard reaction. The mate color changes during storage were: L* reduction in the samples on paper package (from 49.3 to 48.1) and L* increase in the samples on laminated package (from 49.3 to 51.5); -a* reduction and b* reduction in the product on both packages, paper (a*=from -13.2 to -5.9; b*=from 29.3 to 28.5) and laminated film (a*=from -13.3 to -7.0; b*=from 29.5 to 24.9). It was concluded that the storage time and the kind of package significantly influenced (P<0.05) the items analized and that the color change was probably influenced by pheophytinization as well as by oxidation of chlorophyllian pigments in mate.