Qualidade do melão ‘Orange Flesh’ minimamente processado armazenado sob atmosfera modificada

This work aimed at evaluate the effect of the fresh cut 'Orange Flesh' melon stored under modified atmosphere. The cubes of melons were sanitizationed with 100 mg L-1 of hypoclorite of sodium for one minute, washed, drained and wrapped with different concentrations of O-2 and CO2 in plastic bags of polyethylene (Nylon Polished). They were appraised every other day for ten days as regards the firmness, total pectin, soluble pectin and activity of the polifenoloxidase and peroxidase. At the end of the conservation period, it was verified that melons sustained the firmest texture of the vegetable products under modified atmosphere, and the concentration of 5%O-2 + 3% CO2 showed smaller content of total pectin and together with the concentration of 100% N-2 the smallest content of soluble pectin, the polifenoloxidase activity was not verified as well as of the peroxidase.

Temperature and concentration dependence of density of model liquid foods

Density of binary solutions and combinations of sucrose, glucose, fructose, citric acid, malic acid, pectin, and inorganic salts were measured with an oscillating tube density meter in the temperature range from 10degrees to 60degreesC, at varying concentrations. Density can be predicted with accuracy better than 5 x 10(-5) g cm(-3) using predictive equations obtained by fitting the experimental data. Available literature values agreed well with experimental data. Relations for the excess molar volume of these solutions were derived in terms of mole fraction and temperature. A thermodynamic model for the volumetric analysis of multicomponent aqueous solutions containing electrolyte and non-electrolyte compounds was also proposed. These models can be used for prediction of density of liquid food systems, specially fruit juices and beverages, based on composition and temperature, with high accuracy and without elaborate experimental work.

Packaging to Preserve 'Aurora-1' Peaches from Two Maturity Stages

The main objective of this research was to evaluate chemical and physical changes in 'Aurora-1' peach harvested at two maturity stages, packed in different types of packaging and kept under refrigeration. Fruit were harvested at the mature green and ripe stages, packed in four different types of packaging (control, PD-900 (TM), PVC and PET) and stored at 6 degrees C. The following variables were evaluated every eight days: coloration, accumulated fresh mass loss, firmness, appearance, acidity, total soluble solids contents, soluble sugars, and percentage of pectin solubilization. We observed that the postharvest life was influenced by packaging and the mature green fruits showed lower disease occurrence. Fresh mass loss was lower in packed fruits. The peel of mature green fruits developed a characteristic ripe peach color at the end of storage, but PD-900 (TM) provided a delay in color change. Packaging also influenced the firmness, allowing for more firmness retention than for the control fruits at both harvest stages. The organic acid content decreased in the packaged fruits and increased in the control fruits. In the packaged fruit, the amount of sugar increased until the eighth day and then decreased until the end of the storage period. The 'Aurora-1' peaches did not show compromised quality by packaging use and exhibited an increase in harvest life to 24 days (compared to 16 days for the control).

The Effects of Piece Size and Storage Temperatures on Minimally Processed 'Aurora-1' Peaches

The production of minimally processed fruit has increased significantly in the last few years due to the high nutritional value, convenience and safety of minimally processed fruit. The objective of the present study was to evaluate the effects of the conservation temperature and processing conditions on the quality and shelf-life of minimally processed peaches. The processing procedure consisted of washing, sanitization, peeling and stone removal. To remove the stone, the fruit was cut longitudinally, and three types of products were obtained, including halves, quarters and one-eighth segments. The fruit pieces were immersed in 2% ascorbic acid for 3 min and were packed in rigid polystyrene trays (Meiwa (c) M-54) coated with 14 mu m PVC film (Omnifilm (TM)) (about 200 g per pack). The pieces were stored at 65% RH at 3, 6 or 9 degrees C for 12 days, and were evaluated every four days. The appearance, fresh mass loss, color, O-2 and CO2 concentration, acidity, total soluble solids, total and soluble pectin content and ascorbic acid concentration were measured. Minimally processed peaches stored at 3 degrees C maintained higher quality due to control of ripening and senescence Moreover, an interaction effect between one-eighth segments and a temperature of 3 degrees C was observed, and fruit with a superior appearance and higher soluble solids content was obtained.

Barrier and Mechanical Properties of Clay-Reinforced Polymeric Nanocomposites

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Solid state production of thermostable pectinases from thermophilic Thermoascus aurantiacus

Pectin lyase (Pl) and polygalacturonase (Pg) production by Thermoascus aurantiacus 179-5 was carried out by means of solid-state determination using orange bagasse and wheat bran as a carbon sources. Pg and Pl had optimum activity at pH 5.0 and 10.5 respectively. Maximal activity of the enzymes were determined at 65 °C. Pg was stable in the acidic to neutral pH range and at 60 °C for 1 h. whereas Pl was stable at acidic pH and at 60 °C for 5 h. © 2002 Elsevier Science Ltd. All rights reserved.

Isolamento de fungos produtores de enzimas pectinolíticas

Soil samples collected in the campus, UNESP, Araraquara, SP, were employed to isolate and characterize fungi strains with potential pectinolytic enzymes. These enzymes have arisen great interest due to its increasing application in the food industry. Two hundred forty six strains were isolated based on the appearance of colony on PDA medium, morphology (septate mycelia, nonseptate conidiophore, black conidia, and clublike spore-bearing head), after 48 h of growth at 30°C. Strains were selected in solid medium containing pectin citrus as sole carbon source and 0.5% rutenium red. The characterization of pectinolytic production was performed in solid culture and batch fermentation medium containing pectin citrus. The enzyme pectinolytic production was evaluated at 30°C, without agitation in 100 mL of medium containing 2% pectin citrus, 0.2% ammonium sulphate, 0.2% magnesium sulphate, and 0.05% potassium phosphate. The maximum pectinolytic activity (15U/mL) was observed in the medium after Aspergillus sp CFCF-0492 growth, while Aspergillus sp CFCF-CC1 showed the higher level of the final biomass. The pectinolytic activity is more preserved when the fungi-spores were maintained in agar-Czapeck medium.

Screening for pectinolytic activity of wood-rotting basidiomycetes and characterization of the enzymes

Seventy-five fungal strains from different groups of basidiomycetes, newly isolated from rotten wood, were screened for pectinolytic activity. Despite the fact that basidiomycetes are scarcely referred to as pectinase producers, the polygalacturonase (PG) activity was detected in 76 % of the strains; 16 % with activity higher than 40 nkat/g, 40 % between 13.3 and 40 nkat/g, and 44 % with activity lower than 13.3 nkat/g. The highest productions were obtained among the fungi from order Aphyllophorales, family Polyporaceae. The characterization of the enzymes from the highest PG producers (Lentinus sp., Gloeophyllum striatum, Pycnoporus sanguineus, Schizophyllum commune) showed optimum temperature for catalytic activity at 60-70°C and two peaks of pH optimum (3.5-4.5 and 8.5-9.5). The enzymes exhibited high pH stability (3.0-11.0) but after incubation at 40°C for 1 h their activity dropped by 18-73 %.

Purification of an exopolygalacturonase from Penicillium viridicatum RFC3 produced in submerged fermentation

An exo-PG obtained from Penicillium viridicatum in submerged fermentation was purified to homogeneity. The apparent molecular weight of the enzyme was 92 kDa, optimum pH and temperature for activity were pH 5 and 50-55°C. The exo-PG showed a profile of an exo-polygalacturonase, releasing galacturonic acid by hydrolysis of pectin with a high degree of esterification (D.E.). Ions Ca 2+ enhanced the stability of enzyme and its activity by 30%. The K m was 1.30 in absence of Ca 2+ and 1.16mg mL -1 in presence of this ion. In relation to the Vmax the presence of this ion increased from 1.76 to 2.07 μmol min -1mg -1. Copyright © 2009 Eleni Gomes et al.

Metabolismo de carboidratos não-estruturais em ruminantes

The carbohydrates provide 50 to 80% of the dry matter of grain and roughage and can be divided into structural (cellulose, hemicellulose) and non-structural (starch, pectin and sugars). The non-structural carbohydrates are primarily digested in the rumen and its dynamic process is a sequence for the supply of nutrients to the intestine. The quality and quantity of products resulting from ruminal fermentation are dependent on the type and activity of microorganisms in the rumen influenced by the type of food processing and that are subject of cereal grains that make up the diet. The NSC escape of rumen fermentation to be digested into glucose in the small intestine by pancreatic enzymes of origin (α-amylase) and intestinal mucosa (maltase and isomaltase). Starch is the most important energy supplier of cereals, which are important components of diets for intensive production of milk and meat.

Luminescence Enhancement of Carboxyl-Coated CdTe Quantum Dots by Silver Nanoparticles

Metallic nanoparticles (NPs) have been used to improve the sensibility of biosensors and bioassays either by enhancing radiative emission or inducing quenching process on fluorescent probes. The aim of this research was to study the interaction of silver and silver-pectin NPs with water-dispersed carboxyl-coated cadmium telluride (CdTe) quantum dots (QDs). Metallic NPs were observed to change the emission of these fluorophores through local field effects. In a solution-base platform, an increase of 82 % was observed for the CdTe emission due to the interaction of QDs and silver-pectin NPs. QDs interaction with silver NPs without pectin was also investigated and a smaller emission enhancement of 20 % was detected. We observed that the NPs' nature and QDs' surface charge and concentration are important parameters for NPs-QDs interaction. Moreover, the presence of the pectin polymer shows to be a key component to the observed fluorescence enhancement. © 2013 Springer Science+Business Media New York.

Estádios de maturação de pêssegos 'Aurora-1' para o processamento mínimo

The experiment aimed to verify the effect of maturation stage on the quality of minimally processed peaches. Fruits were used in two stages of maturity, on time corresponding to the background color yellow-green, and mature, which corresponds completely to the background color yellow. The minimum process consisted of washing, sanitizing, enzyme peel, cut lengthwise and removed the stone fruits. Halves obtained were immersed in water chlorinated to 10 mg L-1 of water and left on standing to drain the excess liquid. Afterwards, it was proceeded the packaging of the halves in containers of polyethylene terephthalate (PET) and with transparent lid, and the storage at 3 ± 2 ° C and RH = 65% for 12 days, with assessments every three days. The variables evaluated were appearance, weight loss, firmness, soluble solids, titratable acidity, soluble and reduced sugars, ascorbic acid, total and soluble pectin, coloring and activity of polyphenoloxidase. The storage of minimally processed peaches 'Aurora-1' mature harvested was limited mainly by the loss of freshness and firmness, and because they have darker appearance, and lower levels of reduced sugars and ascorbic acid. Peaches 'Aurora-1', harvested at the maturity stage on time, had better quality and longer duration of their minimally processed products.

Optimisation of High Hydrostatic Pressure Processing of Pêra Rio Orange Juice

The influence of high hydrostatic pressure (HHP) on Pêra Rio orange juice was investigated using response surface methodology. A central composite design was used to evaluate the effects of three processing conditions (independent variables), namely pressure (100-600 MPa), temperature (30-60 °C) and time (30-360 s), on the native microflora and pectin methylesterase (PME) activity of orange juice. Analysis of variance showed that second-order polynomial models fitted well with the experimental data for PME residual activity (R2 = 0.9586, p < 0.001) and aerobic microorganism count (R2 = 0.9879, p < 0.001). The optimum HHP processing conditions to produce orange juice with PME residual activity of less than 20 % and low microorganism count (<2 log cycles CFU/mL) were 550 to 600 MPa, 55 to 60 °C and 330 to 360 s. © 2013 Springer Science+Business Media New York.

Efeito da pectina cítrica sobre o desenvolvimento e a saúde do intestino delgado de frangos de corte

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Contribuição ao estudo bioquímico de frutas tropicais e exóticas produzidas no Brasil: pectina, açúcar e proteína

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)