Mango is a highly perishable fruit with a short post-harvest time due to the intense metabolic activity after harvesting. In attempt to evaluate the effects of chitosan in mango fruits, it was treated with 0%, 1%, 2% or 3% of chitosan solutions, placed into plastic trays, and stored at room temperature. Changes in physical and chemical parameters were evaluated. Chitosan delayed the climacteric peak, water loss and firmness. Further, few changes in soluble solid content, titratable acidity, pH of the pulp as well as in sugar content and decreased starch degradation were observed. Altogether, our results suggest chitosan edible coating effectively prolongs the quality attributes, affecting basic mitochondrial respiration and starch degradation rate.

Guava is a typically tropical fruit highly perishable with a short shelf-life due to intense metabolic activity after harvested. In attempt to minimize the problems related to the postharvest, we evaluated the physiochemical characteristics and antioxidant system in guava fruits under chitosan coating at concentrations of 1%, 2%, and 3% stored at 25°C during 96h. The chitosan suppressed the respiratory rate, fresh weight loss, firmness and skin color with delay in the degradation of chlorophyll. In the treatment with 2% and 3% of chitosan in the solid soluble content and ascorbic acid were reduced; retarded the loss of titratable acidity during 96h after treatment. These treatment induced significant decreases in the phenylalanine ammonia-lyase activity and significantly increases of peroxidase Activity. Our results suggest that chitosan effectively prolongs the quality attributes in guava fruits after harvesting due to increases in the antioxidant processes, delaying the ripening during room temperature of storage.

O trabalho avaliou o efeito das doses de silicato de cálcio aplicadas superficialmente no solo afim  de tornar uma nova fonte para correção da acidez do solo e outros atributos químicos do solo e manutenção dos níveis de Si adequados para a planta de Brachiaria ruziziensis L e no desenvolvimento da Poaceae cultivado em casa de vegetação.  Utilizou-se o delineamento inteiramente casualizado em um experimento simples com seis tratamentos e quatro repetições cada, totalizando 24 unidades experimentais. Foram compostos por seis doses de Silicato de Cálcio, a saber: T1 = 0 kg ha-1, T2 = 200 kg ha-1, T3 =  400 kg ha-1, T4 = 800 kg ha-1, T5 = 1600 kg ha-1 e T6 = 3200 kg ha-1 em cultivo de Brachiaria ruziziensis. Foram semeadas dez sementes da gramínea em vasos de 10 dm-3 e, após a emergência realizado desbaste, deixando apenas três plantas em cada vaso. O primeiro corte, rente ao solo, foi realizado aos 120 dias após a emergência, rente ao solo para a quantificação da fitomassa fresca e seca da parte aérea e radicular.  O silicato de cálcio foi eficiente na elevação das concentrações de Ca2+, a soma de bases (SB) e a saturação por bases (V%), aumentando os valores do pH do solo, neutralizando possíveis efeitos tóxico do alumínio (Al+3), e o uso  da fonte de Si não foi eficaz na percentagem de absorção do elemento para o interior da planta de Brachiaria ruziziensis, não alterando a produção de biomassa da raiz e parte aérea.Palavras-Chave: Silício; Acidez do Solo, Fertilidade.

RESUMO -Com o objetivo de prolongar o período de conservação e manter a qualidade do mamão UENF/ Caliman01, foram testadas diferentes concentrações de CaCl 2 aplicadas por infiltração a vácuo. Os frutos foram separados em seis lotes, o controle (sem tratamento) e os tratamentos que receberam a aplicação de CaCl 2 a 0%, 2%, 4%, 6% e 8% CaCl 2 (p/v) por imersão sob vácuo, por 3 minutos, a 50kPa de tensão, com posterior análises da perda de massa fresca, firmeza do fruto, firmeza do mesocarpo, ângulo de cor hue, teores de sólidos solúveis (SS), acidez titulável (AT), ácido ascórbico, açúcares solúveis totais e razão SS/AT. Os tratamentos com cálcio não interferiram na perda de massa que, de modo geral, incrementou ao longo do tempo, porém os frutos permaneceram verdes e firmes por mais tempo quando tratados com CaCl 2 6% e 8% (p/v). O uso do CaCl 2 não interferiu nas características químicas do fruto, tais como sólidos solúveis, acidez titulável e razão SS/AT, porém diminuiu a síntese de ácido ascórbico e a degradação dos açúcares solúveis. Termo para indexação: Carica papaya, qualidade, açúcares solúveis, textura de polpa, coloração de casca, CaCl 2 . TREATMENT WITH CALCIUM CHLORIDE AT POSTHARVEST DELAYS THE DEGREENING AND LOSS OF FIRMNESS OF PAPAYA/UENF/CALIMAN01ABSTRACT -In order to prolong the shelf life and maintain the quality of Papaya/UENF/Caliman01, different concentrations of CaCl 2 applied by vacuum infiltration were tested. The fruit were separated into six groups: control (no treatment) and treatments with CaCl 2 at 0%, 2%, 4%, 6%, and 8% CaCl 2 (w/v), applied by immersion under vacuum during 3 min at 50kPa tension. Further analysis was then performed with respect to weight loss, fruit firmness, mesocarp firmness, hue angle color, soluble solids (SS), titratable acidity (TA), ascorbic acid, total sugars, and the SS/TA ratio. The calcium treatment did not affect the weight loss, which generally increased over time. However, the fruit remained green and firm longer when treated with CaCl 2 at 6% and 8% (w/v). The use of CaCl 2 did not affect chemical fruit characteristics such as soluble solids, titratable acidity, and SS/TA ratio, but did decrease the synthesis of ascorbic acid and the degradation of soluble sugars.

foi instalado em delineamento experimental inteiramente casualizado, em esquema fatorial 4x5, sendo quatro concentrações de 1-MCP (0; 200; 400 e 600 ŋL L‫)¹-‬ e cinco períodos de avaliação após a colheita, em intervalo de cinco dias, com quatro repetições e quatro frutos por unidade experimental. As atemoias foram colhidas em pomar comercial, no município de Matias Cardoso-MG, no estádio de maturação fisiológica, lavadas, sanitizadas e secas ao ar, depois tratadas com as concentrações de 1-MCP por oito horas, em temperatura ambiente. Logo após, quatro frutos foram dispostos em bandejas de poliestireno expandido. Alguns permaneceram sem membrana, enquanto outros foram embalados com membrana plástica de PEBD 16μm. As variáveis avaliadas nos frutos foram: perda de biomassa fresca, firmeza, concentração de CO 2 , etileno e coloração da casca. O uso da atmosfera modificada e do 1-MCP, associados ou não, foi eficiente no atraso do amadurecimento dos frutos, permitindo a conservação de sua qualidade física. Frutos tratados com 1-MCP apresentaram-se mais firmes, além da preservação da coloração, verificada através da luminosidade, cromaticidade e ângulo Hueº, que se mostraram superiores quando comparados aos frutos não tratados. termos para indexação: Annona squamosa x Annona cherimola, amadurecimento, qualidade física, pós-colheita, etileno. preservation in phYsical attriButes of atemoYa cv. Gefner fruit with the use of 1-mcp and modified atmosphere aBstract -The commercial interest by atemoya is increasing more and more in Brazil. The increased respiratory activity accompanied by rapid changes in the physical composition of the fruits may prevent their distribution to distant markets. In this context, the aim of this study was to evaluate the physical attributes in atemoya fruits treated with 1-methylcyclopropene (1-MCP) and modified atmosphere associated with refrigeration. The experiment was carried out in a randomized design, in a factorial 4x5, four concentrations of 1-MCP (0, 200, 400 and 600 nL L-¹), and five evaluation periods after harvest, in the range of five days, with four replications and four fruits per experimental unit. The atemoya were harvested, from a commercial orchard in the municipality of Matias Cardoso, North of Minas Gerais, at the physiological maturity, rinsed, sanitized and air dried, then treated with concentrations of 1-MCP for eight hours at room temperature. Soon after, four fruits were placed in polystyrene trays. Some remained without membrane, while others were packed with plastic film of LDPE 16 μm. The variables evaluated in the fruits were: fresh biomass loss, firmness, concentration of CO 2 , ethylene and peel color. The use of modified atmosphere and 1-MCP alone or combined, were effective in delaying fruits ripening allowing the preservation of its physical quality.Fruits treated with 1-MCP were firmer, as well as preservation of staining, verified by luminosity, chroma and Hue º angle, which proved to be superior when compared to untreated fruits.

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We describe detailed procedures to get intact and well-coupled mitochondria from a variety of fruit species such as papaya (Carica papaya), guava (Psidium guajava), tomato (Solanum lycopersicum), and strawberry (Fragaria x ananassa) as well as the protocols to assess the capacities of AOX and UCP pathways in intact fruit mitochondria. The procedures presented here were tested for the species mentioned above; their use with other types of fruits must be tested for yield of intact and active mitochondria. This is possible from individual adjustments. Strict care during extraction, including the use of osmotic protectants (i.e., mannitol/sucrose) and antioxidants (i.e., cysteine, ascorbate) at defined concentrations, are critical factors to ensure mitochondrial integrity and to obtain higher yields. The mitochondria purified using the discontinuous Percoll gradients described here can be used for the analysis of the capacity of alternative respiration and uncoupling pathways in fruits. In addition, protocols for quantitative and semiquantitative PCR applicable for the analysis of AOX and UCP gene expression in fruits are shown. Microarray and RNA-seq data from public databases are also valuable for the analysis of AOX and UCP genes. In both cases having the sequences of genes or cDNAs to be used in primer design or probe identification is necessary.

The molecule vitamin C, in the chemical form of ascorbic acid (AsA), is known to be essential for the metabolism of humans and animals. Humans do not produce AsA, so they depend on plants as a source of vitamin C for their food. The AsA synthesis pathway occurs partially in the cytosol, but the last oxidation step is physically linked to the respiratory chain of plant mitochondria. This oxidation step is catalyzed by l-galactono-1,4-lactone dehydrogenase (l-GalLDH). This enzyme is not considered a limiting step for AsA production; however, it presents a distinguishing characteristic: the l-GalLDH can introduce electrons directly into the respiratory chain through cytochrome c (Cytc) and therefore can be considered an extramitochondrial electron source that bypasses the phosphorylating Complex III. The use of Cytc as electron acceptor has been debated in terms of its need for AsA synthesis, but little has been said in relation to its impact on the functioning of the respiratory chain. This work seeks to offer a new view about the possible changes that result of the link between AsA synthesis and the mitochondrial respiration. We hypothesized that some physiological alterations related to low AsA may be not only explained by the deficiency of this molecule but also by the changes in the respiratory function. We discussed some findings showing that respiratory mutants contained changes in AsA synthesis. Besides, recent works that also indicate that the excessive electron transport vial-GalLDH enzyme may affect other respiratory pathways. We proposed that Cytc reduction by l-GalLDH may be part of an alternative respiratory pathway that is active during AsA synthesis. Also, it is proposed that possible links of this pathway with other pathways of alternative electron transport in plant mitochondria may exist. The review suggests potential implications of this relationship, particularly for situations of stress. We hypothesized that this pathway of alternative electron input would serve as a strategy for adaptation of plant respiration to changing conditions.