Mudanças nas pectinases, fibras dietéticas e índices físico-químicos relacionados ao sabor de frutos de cubiu durante a maturação

The objective of this study was to evaluate the changes in the activity of pectinases (pectinesterase and polygalacturonase), dietary fiber content (alcohol-insoluble solids, pectin, and total fiber), and physicochemical indices related to the flavor (pH, titratable acidity, soluble solids, Brix/acid ratio, and reducing and nonreducing sugars) of cubiu fruits (Solanum sessiliflorum Dunal) at different stages of ripening (green, turning, ripe, and fully ripe). Alcohol-insoluble solids and pectin were very similar, with the highest levels detected at the green and turning stages, and the lowest levels occurring at the fully ripe stage. The amount of total fiber was consistent at the green, turning, and ripe stages, but declined at the fully ripe stage. These changes correlated with the pectinase activities, the profiles of which resembled those of other species of the Solanaceae family during fruit ripening. However, cubiu fruits were significant sources of dietary fiber at all stages. The reducing sugar content reached the highest level at the turning stage, with glucose as the major sugar. The content of nonreducing sugars, such as sucrose, remained low at all stages. The other physicochemical indices displayed increases during ripening, characterizing cubiu as a very acidic fruit with a small degree of sweetness. © 2015, Eduem - Editora da Universidade Estadual de Maringa. All rights reserved

Conservation of pcjibaye heart-of-Palm in modified atmosphere

The market for pejibaye (Bactris gasipaes) heart-of-palm is expanding rapidly in Brazil and is starting to differentiate into various market niches, including a fresh product niche. Conservation of ready-to-use, minimally processed fresh heart is difficult and requires research on refrigeration and modified atmosphere to enhance shelf-life. The sensory characteristics of fresh heart-of-palm were evaluated during its storage in polyethylene bags under refrigeration with and without an oxygen absorber. Texture, crispness, fiber, humidity, astringency and acridity remained acceptable until the end of the trial at 25 days, although each was extremely variable from day to day, probably due to within-package genotype variation. Color, appearance, sweetness and sourness remained acceptable for 14 days and deteriorated from the 18th day on. Sourness increased significantly (p = 0.02) in the treatment with reduced oxygen, especially after the 18th day and was the most objectionable characteristic. The use of oxygen absorbent did not significantly improve the shelf-life of fresh heart-of-palm, although the use of polyethylene may have reduced the efficiency of the absorbent.O mercado do palmito de pupunha (Bactris gasipaes) está expandindo rapidamente no Brasil e diferenciando-se com a inclusão do palmito fresco ou minimamente processado. Devido sua alta perecibilidade, a conservação desse palmito fresco é difícil e requer estudos de conservação em refrigeração aliada à atmosfera modificada. As qualidades sensoriais do palmito fresco foram avaliadas ao longo de sua conservação sob refrigeração, em sacos de polietileno, com e sem absorvente de oxigênio. A textura, crispidez, fibrosidade, umidade, adstringência e irritação permaneceram aceitáveis até os 25 dias, embora altamente variáveis de um dia para o outro, provavelmente devido à variação entre os genótipos em cada embalagem. A cor, aparência, doçura e amargor permaneceram aceitáveis até 14 dias e deterioraram a partir do 18º dia. O amargor aumentou significativamente (p = 0,02) no tratamento com absorvente de oxigênio, especialmente a partir do 18º dia, sendo a principal característica responsável pela rejeição do palmito. O uso do absorvente de oxigênio não aumentou significativamente a vida de prateleira do palmito fresco, embora o polietileno usado possa ter reduzido a eficácia do absorvente

Quality Attributes of Cupuaçu Juice in Response to Treatment with Crude Enzyme Extract Produced by Aspergillus japonicus 586

Cupuaçu (Theobroma grandiflorum Schum) is an Amazonian Basin native fruit whose fruit pulp is consumed as a juice which presents high density, viscosity, and turbidity. Pectic enzymes, usually yielded by microorganisms, are used to reduce the juice viscosity and turbidity. The present study aims to evaluate the use of pectic enzymes when processing cupuaçu juice. The cupuaçu juice was obtained by using Aspergillus japonicus 586 crude enzyme extract and incubation at 50°C with agitation (140 rpm) for one hour. Enzyme activities were determined, and the juices were evaluated as to their yield, turbidity, viscosity, and chemical composition. The juice produced by using crude enzyme extract presented higher soluble solids, reducing sugars, and lower viscosity and turbidity

Cinética de secagem da polpa cupuaçu (Theobroma grandiflorum) pré desidratada por imersão-impregnação

The osmotic dehydration is an important unitary operation to transform the perishable fruits in new products with added value and longer shelf life. The application of reliable mathematical models allows prediction the behavior of various phenomena that occur during the drying process, which implies in reduction of operating cost. The cupuaçu pulp is commonly used to prepare juices and ice creams, but during the crop it is produced in large quantity, which is often discarded because of the cost of production is higher than the selling price. The aim of this study was to investigate the effect of binary and ternary solutions at the rate of convective drying and evaluate the adequacy of mathematical models to describe the drying curves of the cupuaçu. In the experiment, osmotic dehydration was carried out with binary (sucrose at 40°Brix) and ternary (80% sucrose/20% sodium chloride) solutions for three hours at room temperature, followed by conventional drying in an oven (air-circulating) at 65°C to constant weight. The experimental data were adjusted using the models of Page and Midilli, Kucuk and Yapar. The binary solution used during predrying, reduced the time of the subsequent conventional drying. Varying from 99.64 to 99.77% in the coefficient of determination (R2), the Page model showed a better adjustment to experimental data

Enzimas hidrolíticas extracelulares de isolados de rizóbia nativos da Amazônia Central, Amazonas, Brasil

Legumes enrich the soil by contributing nitrogen through symbiotic biological nitrogen fixation by rhizobia bacteria. However, very little is known about the extracellular enzymatic profile of these microorganisms. In this context, the production of extracellular hydrolytic enzymes by indigenous strains of rhizobia in Central Amazonia was evaluated. This screening constitutes the first step in selecting indigenous microorganisms that are potentially exploitable as enzyme producers. Indigenous strains of rhizobia were screened for extracellular amylolytic, carboxymethylcellulolytic, lactolytic, lipolytic, pectinolytic and proteolytic activities on modified YMA. Ureolytic activity was detected on a urea-agar slant. Rhizobia strains isolated from cowpea nodules produced more enzymes than those isolated from soybean nodules. Out of all the extracellular hydrolytic enzymes evaluated, only pectinase was not detected in this study. The most frequent rhizobia enzymes were amylase (32.8%), protease (28.4%), urease (20.9%) and carboxymethylcellulase (9.0%). In this study, only amylase and protease enzymes varied significantly among rhizobia strains. INPA strains R-926 and R-915 showed the highest enzymatic levels for amylase (EI = 3.1) and protease (EI = 6.6), respectively. This paper showed some indigenous strains of rhizobia from Central Amazonia as promising sources of industrially relevant enzymes for biotechnological purposes

Produção de amilase por rizóbios, usando farinha de pupunha como substrato

Amylases are among the most important industrial enzymes and are of great significance in present-day biotechnology. Although they can be derived from various sources, enzymes from microbial sources are generally the most required by industry. Species of the genus Bacillus are considered to be the main sources of amylases, although screening for new microbial sources is increasing all over the world. The objective of the present study was to evaluate the production of amylase by indigenous rhizobia, using peach palm flour as substrate. In this study, a completely randomized experimental design was adopted with three replicates. Pearson's correlation coefficients were calculated for medium pH, extracellular protein, cellular biomass, mean colony diameter (MCD), mean halo diameter (MHD), enzymatic index (EI) and amylolytic activity variables from the bacteria selected. Out of the 19 rhizobia strains with amylolytic activity on modified YMA, seven (36.8%) strains showed "EI" ≥ 2,1, and they were considered as good producers of amylase. The "IE" presented by bacteria INPA R-987, R-950 and R-915B were significantly lower (p < 0.01) than those shown by the INPA R-926, R-975 and R-957. The amylolytic activity varied significantly (p < 0.01) among the rhizobia strains. INPA R-975 and R-926 strains presented, respectively, the highest (1.00 U.min-1.mL-1) and the lowest (0.31 U.min-1.mL-1) activity average. In general terms, the extracellular protein was correlated positively with "EI" (r = 0.52*; p < 0.05) and "MHD" (r = 0.55*; p < 0.05). The cellular biomass showed positive correlations with amylolytic activity (r = 0.55*; p < 0.05) and "MHD" (r = 0.54*; p < 0.05), and a negative with final pH medium (r = 0.93**; p < 0.01)

Suitability of Amazonian Fruit: Araçá-Boi (Eugenia stiptata McVaugh) for Liquor Production

The potential of araçá-boi for liquor processing was studied through fruit pulp composition and the effect of processing parameters, such as: extraction liquid type, maceration time, pulp/extraction liquid ratio, proportion of syrup/extract and syrup processing method. The araçá-boi presents good characteristics for liquor processing, such as, acidic pH, high titrable acidity, soluble solids and total carotenoids contents. For the araçá-boi liquor processing the optimized parameters were five days for maceration time; 1:2 (g/ml) of pulp/extraction liquid ratio at maceration; the 1:0.5 (ml/ml) of syrup/extract ratio at the formulation; preparation of the syrup using heat; utilization of the corn alcohol. With this conditions, a good product is obtained.Para avaliar o potencial do araçá-boi para produção de licores, foi estudada a composição química da polpa e o efeíto de alguns parâmetros do processamento, tais como, tipo de líquido extrator, tempo de maceração, proporção polpa/líquido extrator, proporção xarope/extrato c método de preparo do xarope. O araçá-boi apresentou boas características para o processamento de licor, como o pH ácido, altos teores de acidez titulável, sólidos solúveis e carotcnóides totais. Os parâmetros ideais para obtenção de licor de boa qualidade foramcinco dias de maceração na proporção de 1:2 (p/v) de polpa:álcool de milho, relação de 1:0,5 (v/v) de xarope:cxtrato na formulação, utilizando-se xarope preparado com dissolução do açúcar sob aquecimento

Phenotypic, genetic and environmental correlations between Morphological and chemical descriptors in fruits of Cubiu (Solanum sessiliflorum Dunal) in Amazonia

The cubiu (Solanum sessiliflorum Dunal) is a fruiting shrub domesticated by indians in Amazonia, and produces 40 to 100 t/ha of fruit rich in minerals and vitamins. The fruits are traditionally used for juices, ice-creams, sweets and in sauces for meat, chicken and fish. Thirteen chemical and morphological characters of 24 etnovarieties of cubiu from Brazilian, Peruvian and Colombian Amazonia were used to estimate the coefficients of phenotypic (r), genetic (rg) and environmental (rc) correlation between pairs of characters. In most cases, the genetic correlations were higher than the phenotypic and environmental correlations, indicating that the environment had less influence. Among the morphological characters, fruit dimensions were closely correlated with moisture. There were no correlations between morphological and chemical characters that could be useful in cubiu improvement. Among the chemical characters, the correlations between brix and acidity and reducing sugars and total sugars were high and positive (r = 0,62 and rg = 0,83, respectively). Thus, it will be difficult to simultaneously select for these without losing genotypes.O cubiu (Solanum sessiliflorum Dunal) é uma hortaliça da Amazônia, domesticada pelos índios, que pode produzir até 100 t/ha de frutos ricos em sais minerais e vitaminas. Os frutos são utilizados pelas populações tradicionais da região nas formas de sucos, sorvetes, doces e molhos para carnes bovina, de frango e de peixes. Treze caracteres morfológicos e químicos dos frutos de 24 etnovariedades da Amazônia brasileira, peruana e colombiana foram utilizadas para estimar os coeficientes de correlações fenotípica (rf), genética (rg) e de ambiente (ra) entre pares de caracteres. Na maioria dos casos, as correlações genéticas apresentaram valores superiores aos das fenotípicas e de ambientes, indicando que o ambiente teve pouca influência. Entre os caracteres morfológicos, as dimensões dos frutos são estreitamente relacionadas com o teor de umidade. Não foram observadas correlações entre caracteres morfológicos e químicos que pudessem ser úteis ao melhoramento do cubiu. Entre os caracteres químicos, as correlações entre brix e acidez e açúcares redutores e açúcares totais foram altas e positivas (rg = 0,62 e rg = 0,83), respectivamente. Entre vários caracteres químicos será difícil praticar seleção simultânea sem perda de genótipos

Proteomic analysis of Chromobacterium violaceum and its adaptability to stress

Chromobacterium violaceum (C. violaceum) occurs abundantly in a variety of ecosystems, including ecosystems that place the bacterium under stress. This study assessed the adaptability of C. violaceum by submitting it to nutritional and pH stresses and then analyzing protein expression using bi-dimensional electrophoresis (2-DE) and Maldi mass spectrometry. Chromobacterium violaceum grew best in pH neutral, nutrient-rich medium (reference conditions); however, the total protein mass recovered from stressed bacteria cultures was always higher than the total protein mass recovered from our reference culture. The diversity of proteins expressed (repressed by the number of identifiable 2-DE spots) was seen to be highest in the reference cultures, suggesting that stress reduces the overall range of proteins expressed by C. violaceum. Database comparisons allowed 43 of the 55 spots subjected to Maldi mass spectrometry to be characterized as containing a single identifiable protein. Stress-related expression changes were noted for C. violaceum proteins related to the previously characterized bacterial proteins: DnaK, GroEL-2, Rhs, EF-Tu, EF-P; MCP, homogentisate 1,2-dioxygenase, Arginine deiminase and the ATP synthase β-subunit protein as well as for the ribosomal protein subunits L1, L3, L5 and L6. The ability of C. violaceum to adapt its cellular mechanics to sub-optimal growth and protein production conditions was well illustrated by its regulation of ribosomal protein subunits. With the exception of the ribosomal subunit L3, which plays a role in protein folding and maybe therefore be more useful in stressful conditions, all the other ribosomal subunit proteins were seen to have reduced expression in stressed cultures. Curiously, C. violeaceum cultures were also observed to lose their violet color under stress, which suggests that the violacein pigment biosynthetic pathway is affected by stress. Analysis of the proteomic signatures of stressed C. violaceum indicates that nutrient-starvation and pH stress can cause changes in the expression of the C. violaceum receptors, transporters, and proteins involved with biosynthetic pathways, molecule recycling, energy production. Our findings complement the recent publication of the C. violeaceum genome sequence and could help with the future commercial exploitation of C. violeaceum