Alterações fisiológicas e bioquímicas em sementes de café secas em sílica gel e soluções salinas saturadas

The objective of this work was to evaluate the physiological and biochemical changes in coffee seed subjected to rapid drying, in silica gel, or to slow drying in saturated saline solutions. Seeds were dried until they reached the following water contents: 40, 30, 20, 15, 10, and 5% (wet basis). After drying, part of the seeds was immediately evaluated as to their physiological performance and enzymatic profile of the oxidative process, and another part was evaluated after storage, under hermetic conditions, in freeze‑drying chamber, for four months. Drying rate and final moisture content had significant effect on seed physiological quality. After rapid drying, in silica gel, seeds tolerated lower final moisture levels. However, after slow drying, seeds with greater water levels showed higher quality. The storage period did not affect germination, but it reduced coffee seed vigor. Rapid drying shows greater damage potential to the endosperm than to the embryos. The enzymatic profile of coffee seed is affected by the final moisture level and the drying rate.O objetivo deste trabalho foi avaliar alterações fisiológicas e bioquímicas em sementes de café submetidas à secagem rápida, em sílica gel, e à secagem lenta, em soluções salinas saturadas. As sementes foram secas até que atingissem os seguintes teores de água: 40, 30, 20, 15, 10 e 5% (base úmida). Após a secagem, uma parte das sementes foi imediatamente avaliada quanto ao desempenho fisiológico e ao perfil de enzimas do processo oxidativo, e outra parte foi avaliada após armazenagem em condição hermética, em câmara fria e seca, por quatro meses. A velocidade de secagem e o teor final de água tiveram efeito significativo sobre a qualidade fisiológica das sementes. Após a secagem rápida em sílica gel, as sementes toleraram teores finais de água mais baixos. No entanto, após a secagem lenta, as sementes com teores finais de água mais elevados apresentaram maior qualidade. O período de armazenamento não afetou a germinação, mas prejudicou o vigor das sementes. A secagem rápida apresenta maior potencial de dano ao endosperma do que aos embriões. O perfil enzimático das sementes de café é afetado pelo teor final de água e pela velocidade de secagem

Quality evaluation of Coffea canephora ‘Apoatã’ seeds for rootstock production

Coffea canephora ‘Apoatã’ seeds are used for the formation of rootstocks for grafting of C. arabica seedlings. The quality of seeds and the individualization of used genotypes are prevalent factors for the formation of vigorous rootstocks that will enhance the formation of quality seedlings. The aim of the present study was to characterize and evaluate the seed quality of C. canephora ‘Apoatã’ genotypes for potential use of rootstocks for C. arabica species. Were used seeds of 30 C. canephora ‘Apoatã’ genotypes, obtained from the experimental field of Embrapa Rondônia in Ouro Preto do Oeste, RO, Brazil. The seeds were processed and subjected to germination, first germination count and tetrazolium tests. Moisture, 100- seed mass and chemical composition analyses of seeds were also determined. The mass, physiological quality and chemical composition of C. canephora ‘Apoatã’ seeds vary according to the genotype. The variation of the physiological quality of C. canephora ‘Apoatã’ seeds is not related individually to caffeine, total sugars, ash, ether extract, crude fiber protein and chlorogenic acid. Seed batches of C. canephora ‘Apoatã’ from different genotypes contain seeds of different sizes, being indicated the classification before the processing stage in order to prevent mechanical damages

Enzimas antioxidantes preservan la calidad del café en ambiente refrigerado

Post-harvest phases may cause biochemical and physiological changes with direct effects on coffee (Coffea sp.) grains quality during its storage. The aim of this study was to determine the relevance of antioxidant isoenzyme expression on the coffee grains quality undergoing different types of processing and storage conditions. Coffea arabica L. ripe fruits was harvested, part of them was dry processed and another part was wet processing. Immediately, the coffee was dried. After drying, some of the grains were hulled and the other part was maintained unhulled. After that, the grains were stored under refrigerate controlled conditions (10 degC and 50% relative humidity) or at 25 °C without relative humidity control for a period of 12 months. Enzymatic expression of catalase, esterase, peroxidase, and alcohol dehydrogenase enzymes was evaluated in the coffee grains in these storage conditions by electrophoretic analysis. The results were compared to the sensorial and physiological profiles of the samples. It was found that expression of enzymes of the antioxidative process is associated with changes in the quality of coffee grains. Natural coffee obtained by dry processing is more sensitive to biochemical changes than wet-processed coffee. A refrigerated environment has a beneficial effect for preserving the coffee grains showed by higher expression of catalase, peroxidase, and alcohol dehydrogenase enzymes after six months of storage in these conditions. The protection of the endosperm by the presence of the pericarp in natural coffee or the endocarp in fully-washed coffee is beneficial to maintenance of quality and is related to expression of antioxidant enzymes.Keywords: alcohol dehydrogenase, catalase, Coffea arabica L., esterase, peroxidaseLas etapas de la poscosecha pueden causar alteraciones bioquímicas y fisiológicas con efectos directos en la calidad de los granos de cafeto (Coffea spp.) durante su almacenamiento. El objetivo de este trabajo fue determinar la relevancia de la expresión de isoenzimas del proceso antioxidante, en la conservación de la calidad de los granos sometidos a diferentes tipos de procesamiento y condiciones de almacenamiento. Los frutos de Coffea arabica L. fueron cosechados en estado de maduración cereza y secados, luego de ser beneficiados por vía seca y por vía húmeda. Después del secado, parte de los granos fue trillada y otra parte conservada en coco o en pergamino. Luego, los granos fueron almacenados en condiciones controladas de aire refrigerado (10 °C y humedad relativa del 50%) o a 25 °C sin control de la humedad relativa, durante un periodo de 12 meses. La expresión enzimática de las enzimas catalasa, esterasa, peroxidasa y alcohol deshidrogenasa fue evaluada en los granos de café a lo largo del almacenamiento por medio de un análisis electroforético. Estos resultados fueron comparados con el perfil sensorial y fisiológico de las muestras. Se constató que la expresión de las enzimas del proceso antioxidante, está asociada con alteraciones en la calidad de los granos de café. El café natural obtenido por beneficio mediante secado, es más sensible a las alteraciones bioquímicas del beneficiado por vía húmeda. El efecto beneficioso de la refrigeración del aire de almacenamiento en la preservación de la calidad del café, es evidenciado por la mayor expresión de las enzimas estudiadas después de seis meses. La expresión de las enzimas del proceso antioxidante, está asociada al efecto protector del pericarpio y endocarpio.Palabras clave: alcohol deshidrogenasa,catalasa, Coffea arabica L., esterasa, peroxidas

Physiological quality of tomato seeds treated with polymers in combination with paclobutrazol

Abstract: In tomatoes production system, etiolation is the main cause of seedlings loss. Some inhibitors, such as paclobutrazol (PBZ), have been used to reduce this problem. This study aimed to evaluate the effect of different doses of paclobutrazol, with and without polymer association, at different degrees of permeability, on the physiological quality of seeds. Seeds of two tomato cultivars, Ozone and Paronset, were treated with four concentrations of paclobutrazol (0, 0.004, 0.008 and 0.016 g mL a.i.10 g seeds-1), and combined with three fixatives (water, P1 and P2). After the treatments, germination test, germination speed index test and cold test were carried out, and after five months of seed storage, the analyzes were repeated. The increase in PBZ dose reduces both germination percentage and germination speed index. After storage, the product acts differently on seed germination. The synthetic polymers, in the dose used in this study, are effective in PBZ fixation on the seeds coat, but do not reduce the harmful effect of PBZ on seed germination

ALTERAÇÕES NA COLORAÇÃO DE GRÃOS DE CAFÉ SUBMETIDOS A DIFERENTES MÉTODOS DE PROCESSAMENTO E ARMAZENAMENTO

The color evaluation of coffee grains becomes important as atypically colored coffee or different levels of whiteness will receive lower price on the market. In addition to commercial impairment, changes in color are indicative of the occurrence of oxidative processes and biochemical damage, which can alter the flavor and aroma precursors of the grains, resulting in lower beverage quality. Thus, the aim of this study is to evaluate the color characteristics in coffee grains with different levels of quality that were processed, benefited and stored under different conditions. Coffee fruits were harvested in the cherry stage and dry processed and wet processed. Grains were dried until reaching 11% moisture content and subjected to three treatments (manual hulling, mechanical hulling and without hulling), and were stored under two conditions (10ºC and 50% RU; and 25ºC without relative humidity control). After eight months of storing, the color parameters of the grains, the physiological and sensory quality were evaluated. The intensity of the green and blue colors and the brightness of the grains are affected by the processing and hulling methods, and storage conditions. The wet processed coffee grains have a more intense greenish color compared to the dry processed ones. Coffee grains stored under lower temperature have lower brightness indexes and “b” color parameter, as well better physiological quality.A avaliação da cor de grãos de café torna-se importante uma vez que cafés com coloração atípica ou com diferentes níveis de branqueamento receberão menores preços no mercado. Além da desvalorização comercial, a alteração na cor é indicativos da ocorrência de processos oxidativos e alterações bioquímicas que podem modificar os precursores do sabor e aroma dos grãos, reduzindo a qualidade da bebida. Objetivou-se, neste estudo, avaliar as características de cor de grãos de café de diferentes qualidades, os quais foram processados e beneficiados por meio de diferentes métodos, e armazenados em diferentes condições. Frutos de Coffea arabica foram colhidos no estádio cereja e processados, por via úmida e por via seca. Os grãos foram secados até atingirem 11% de teor de água e submetidos a três formas de beneficiamento (manual, mecânico e sem beneficiamento) e a duas condições de armazenamento (10 ºC e 50% de umidade relativa; e 25 ºC sem controle de umidade relativa). Após o armazenamento por oito meses, os parâmetros de cor dos grãos e a qualidade fisiológica e sensorial foram avaliados. A intensidade das cores verde e azul e a luminância dos grãos de café são afetadas pelos métodos de processamento, beneficiamento e condições de armazenamento. Cafés despolpados apresentam coloração verde mais intensa, em comparação aos cafés naturais. O resfriamento do ar de armazenamento de grãos de café a 10ºC propicia menores índices de luminância e da coordenada b, bem como melhor qualidade fisiológica

Minimum period to assess the potential of germination of coffee seeds

In recent research, early stages of coffee seedling development were identified, after radicle protrusion, in which all the essential parts of the seedling can be assessed to demonstrate the potential of seed germination to generate normal plants. Thus, the objective of this research was to develop studies to reduce the time on the germination test. Ten seed lots of coffee were assessed through the germination test, every two days, from the tenth day of sowing, according to the morphological criteria of the seedlings. The data were compared to the standard germination test and analyzed by means of regression analysis and segmented nonlinear regression and planteau response model. It was concluded that the assessment of coffee seedlings at 16 days, in stage S1, provides the similar result of the pattern germination test, allowing a significant reduction of time in order to demonstrate the germination of the seed lots; the seedling assessment coffee in stage S2 does not have reduction of the time for assessing the coffee germination, in relation to the pattern

Desiccation sensitivity from different coffee seed phenological stages

Maturity stage and drying method are the factors that most influence coffee seed quality. The objective of this study was to assess the physiological quality and investigate the electrophoretic patterns of catalase and endo-β-mannanase enzymes and heat resistant proteins in coffee seeds harvested at different phenological stages and dried under different conditions. Physiological quality was assessed when the seeds had developed the green, greenish-yellow, cherry, overripe and dry stages after three treatments: no drying, conventional drying and fast drying. After each treatment, the physiological quality of the seeds was assessed using the germination test and electrophoretic patterns of heat resistant proteins and the activity of catalase and endo-β-mannanase enzymes. Seeds harvested at the cherry phenological stage had the best physiological quality, and the drying process reduced quality at the cherry, overripe and dry stages. This reduction was greater under the faster drying process, but at the greenish-yellow stage, seeds had better physiological quality after slow drying. Regarding the results from electrophoretic analysis, endo-β-mannanase and catalase activities increase as the ripeness stages advance; the activity of endo-β-mannanase is directly associated with the deterioration process; the expression of heat resistant proteins increases with maturation process and is associated with seed physiological quality