ABSTRACT
RESUMEN Se buscó minimizar el efecto de factores ambientales sobre la calidad pos cosecha del tomate, mediante la aplicación de recubrimiento elaborado con almidón de yuca modificado por vía ácida. La modificación de la estructura original de una suspensión de almidón de yuca variedad SM 707-17, se realizó mediante adición de ácido cítrico, en concentración de 15% p/p respecto al almidón en base seca, bajo condiciones de temperatura y de velocidad de agitación controladas. El efecto de este recubrimiento, se comparó con el efecto de la aplicación de otros elaborados con base en almidón modificado enzimáticamente y almidón nativo. Se midieron las variables: sólidos solubles totales, firmeza, pH, acidez titulable, tasa de respiración, pérdida de peso y color durante 15 días, aplicando un diseño factorial completamente al azar 4x6. Los resultados, se analizaron mediante el software SPSS versión 19, con el cual, se encontró que el factor "Recubrimiento" no influyó sobre las variables de respuesta analizadas, a diferencia del factor "Tiempo", que tuvo efecto decisivo sobre las mismas.
ABSTRACT The aim was to minimize the effect of environmental factors on postharvest of tomato quality by applying a coating made with cassava starch modified by acid route. The modification of the original structure of a suspension of native starch of cassava variety SM 707-17, was carried out by addition of citric acid in concentration of 15% w/w with respect to the starch in dry base, under controlled temperature and speed of controlled agitation. The effect of this coating was compared with the effect of the application of others made on the basis of enzymatically modified starch and native starch. The variables total soluble solids, firmness, pH, titrable acidity, respiration rate, weight loss and color for 15 days were measured, applying a completely randomized 4x6 factorial design. The results were analyzed using SPSS software version 19, which found that the "Coating" factor did not influence the response variables analyzed, unlike the "Time" factor that had a decisive effect on them.
ABSTRACT
As telas de sombreamento são amplamente utilizadas para controlar a radiação solar excessiva. Novos aditivos, dispersivos e elementos refletivos têm sido incorporados nas telas durante o processo de fabricação para modificar a qualidade espectral da radiação e obter respostas fisiológicas desejadas. O objetivo do presente trabalho foi avaliar o efeito de diferentes telas de sombreamento no desenvolvimento de mudas de tomateiro (Solanum lycopersicum L. cv. Caline IPA 6). Foram utilizadas quatro telas com 50% de sombreamento (preta, aluminizada, vermelha e cinza). O delineamento experimental foi inteiramente casualizado, com quatro tratamentos e quatro repetições. As variáveis estudadas foram: a altura e diâmetro final das plantas, massa de matéria seca de raiz e parte aérea, índice de clorofila, radiação fotossinteticamente ativa e temperatura do ar. As telas influenciaram no microclima e nas variáveis de crescimento do tomateiro. De acordo com os resultados a tela aluminizada apresentou melhor desempenho que às telas fotosseletivas e preta, embora estudos complementares necessitem serem feitos para maior avaliação do potencial de uso das telas em cultivo com tomateiro.
The shade nets are widely used to control excessive solar radiation. Recently, new additives, dispersive and reflective elements have been incorporated into the netting materials during manufacturing to modify the spectral quality of the radiation in order to reach desired physiological crop responses. The aim of this study was to evaluate the effect of different shade nets in developing seedlings of tomato (Solanum lycopersicum L. cv. Caline IPA 6). Four nets with 50% shading (black, aluminated, red and gray photo-selective nets) were studied. The experimental design was completely randomized with four treatments and four replications. The variables studied were: height and diameter of the final plants, the dry mass of roots and shoots, chlorophyll index, the photosynthesis photon flux density and air temperature. The nets influenced the microclimate variables and the growth of tomato seedlings. According to the results, the aluminated net performed better than the photo-selectives nets and black, although further studies need to be done for further evaluation of the potential use of screens with tomato cultivation.