797 research outputs found

    FIRMNESS INDEXES EVALUATION FOR FRESH-CUT SLICED PINEAPPLE TREATED WITH CALCIUM SALTS SOLUTIONS

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    Fresh-cut sliced fruits and vegetables are ready to eat immediately and their sensorial characteristics should be similar to fresh product. Although most of the studies in this area are focused on vegetables, there is a great market potential for fresh-cut sliced fruits, mainly for those which exhibit some commercialization or preparation difficulties such as pineapple. The objective of this work was to evaluate the effect of 1% and 3% concentrations of calcium salts (chloride, sulphate and lactate) on pH, total soluble solids and firmness values of minimally processed pineapple slices. Two types of indenters and three firmness indexes were investigated aiming to identify the best index. Results showed that calcium sulphate 3% kept average firmness index up to 44.45% higher than the index value of the control. Even though both indenters exhibited similar variability the cylindrical one was able to point out more differences between control and treatments than the cylindrical borer indenter.28115416

    Effect of calcium chloride on quality of fresh-cut 'Perola' pineapple

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    The objective of this research was to evaluate the effects of calcium chloride on quality of fresh cut 'Perola' pineapple. The experimental design was a completely randomized in a 3x5 factorial scheme, and the treatments were represented by the CaCl2 concentration and storage time, each one with three replicates. Fruits were sanitized, peeled mechanically, sliced manually and dipped into water (control) and in CaCl2 solutions (1% and 2%) for 30 seconds. Slices were placed in polyethylene terephtalate packages and stored at 4+/-1 degreesC during periods of 0, 3, 6, 9 and 12 days. Texture was not influenced by any of the studied factors. Smaller peroxidase activity in the samples submitted to CaCl2 2% was verified. Fresh-cut pineapple slices dipped in CaCl2 1% showed more browning, presenting smaller L* value and larger a* value at the end of the storage period. The use of CaCl2 in fresh-cut 'Perola' pineapple does not provide beneficial effects on the texture and interfere negatively on the flesh color of fruit.3891105111

    SENSORY CHARACTERISTICS OF 'DOURADAO' PEACHES SUBMITTED TO MODIFIED ATMOSPHERE PACKAGING

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    The sensory, physical and chemical characteristics of 'Douradao' peaches cold stored in different modified atmosphere packaging (LDPE bags of 30, 50, 60, 75 mu m thickness) were studied. After 14, 21 and 28 days of cold storage (1 +/- 1 degrees C and 90 +/- 5% RH), samples were withdrawn from MAP and kept during 4 days in ambient air for ripening. Descriptive terminology and sensory profile of the peaches were developed by methodology based on the Quantitative Descriptive Analysis (QDA). The assessors consensually defined the sensory descriptors, their respective reference materials and the descriptive evaluation ballot. Fourteen individuals were selected as judges based on their discrimination capacity and reproducibility. Seven descriptors were generated showing similarities and differences among the samples. The data were analysed by ANOVA, Tukey test and Principal Component Analysis (PCA). The atmospheres that developed inside the different packaging materials during cold storage differed significantly. The PCA showed that MA50 and MA60 treatments were more characterized by the fresh peach flavour, fresh appearance, juiciness and flesh firmness, and were effective for keeping good quality of 'Douradao' peaches during 28 d of cold storage. The Control and MA30 treatments were characterized by the mealiness, the MA75 treatment showed lower intensity for all attributes evaluated and they were ineffective to maintain good quality of the fruits during cold storage. Higher correlation coefficients (positive) were found between fresh appearance and flesh firmness (0.95), fresh appearance and juiciness (0.97), ratio and intensity of fresh peach smell (0.81), as well as higher correlation coefficients (negative) between Hue angle and intensity of yellow colour (-0.91), fresh appearance and meatiness (-0.92), juiciness and mealiness (-0.95), firmness and meatiness (-0.94).32370070

    EFFECTS OF MODIFIED ATMOSPHERE PACKAGING ON RIPENING OF 'DOURADAO' PEACH RELATED TO PECTOLYTIC ENZYMES ACTIVITIES AND CHILLING INJURY SYMPTOMS

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    The present study evaluated the effects of modified atmosphere packaging on inhibition of the development of chilling injury symptoms in 'Douradao' peach after cold storage and the possible involvement of cell wall enzymes. Fruits were harvested at the middle stadium of ripening, packed in polypropylene trays and placed inside low density polyethylene (LDPE) bags (30, 50, 60 and 75 mu m of thickness) with active modified atmosphere (10 kPa CO2 + 1.5 kPa O-2, balance N-2). The following treatments were tested: Control: peaches held in nonwrapped trays; MA30: LDPE film - 30 mu m; MA50: LDPE film - 50 mu m; MA60: LDPE film - 60 mu m and MA75: LDPE film - 75 mu m. Fruits were kept at 1 +/- 1 degrees C and 90 +/- 5% relative humidity (RH) for 28 days. After 14, 21 and 28 days, samples were withdrawn from MAP and kept in air at 25 +/- 1 degrees C and 90 +/- 5% RH for ripening. On the day of removal and after 4 days, peaches were evaluated for woolliness incidence, pectolytic enzymes activities. The respiratory rate and ethylene synthesis were monitored during 6 days of ripening. The results showed that MA50 and MA60 treatments had positive effect on the inhibition of the development of woolly texture and reduced pectin methylesterase activity on the ripe fruits, keeping good quality of 'Douradao' peach during 28 days of cold storage. The treatments Control, MA30 and MA75 showed higher woolliness incidence and did not present marketable conditions after 14 days of cold storage.3341084109

    MODIFIED ATMOSPHERE PACKAGING EXTENDING THE STORAGE LIFE OF 'DOURADAO' PEACH

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    'Douradao' peach is a perishable product and when cold stored is subject to chilling injury. The objective of the experiment was to evaluate the effect of modified atmosphere packaging (MAP) and cold storage on quality and storage life of these peaches. Fruits were packed in polypropylene (PP) trays and placed inside low density polyethylene (LDPE) bags (30, 50, 60, 75 mu m thickness) with active modified atmosphere (10 kPa CO2 + 1.5kPa O-2, balance N-2). The control was made with peaches held in nonwrapped PP trays. Fruits were kept at 1 +/- 1 degrees C and 90 +/- 5% relative humidity (RH) for 28 days and CO2 and O-2 within packages was monitored every two days. After 14, 21 and 28 days, samples were withdrawn from MAP and kept in air at 25 +/- 1 degrees C and 90 +/- 5% RH for ripening. On the day of removal from the cold storage and after 4 days, peaches were evaluated for weight loss, decay incidence, flesh firmness, woolliness incidence, soluble solids content (SSC), titratable acidity (TA) and juice content. The results showed that MAP had influence on reducing weight loss and prevented postharvest decay. MAP of 1-2 kPa O-2 and 3-6 kPa CO2 at 1 degrees C (from 50 and 60 mu m LDPE films) were effective for keeping good quality of 'Douradao' peaches during 28 days of storage, the ripe fruits showed reduced incidence of woolliness, adequate juiciness and flesh firmness. Packages of 30 and 75 mu m LDPE films were ineffective for reducing woolliness during cold storage. MAP fruits showed lower SSC and no relevant effect on TA. Control fruits did not present marketable conditions after 14 days of cold storage.3241009101

    Physical and chemical characteristics of minimally processed strawberries stored under refrigeration and controled atmospheres

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    Strawberries cv. Oso Grande were minimally processed and kept in three different atmospheres: 3% O-2 + 10% CO2 (N-2 balance), 3% O-2 + 15% CO2 (N-2 balance) and ambient atmosphere (control), at 5 and 10 degrees C, during, 7 days, with the evaluation of their physical and chemical characteristics during storage. Fruits were evaluated at 0, 3 and 7 days for weight loss, firmness, pH, titratable acidity, soluble solids, sugar content (sucrose, fructose and glucose) and total anthocyanins. Data were subjected to analysis of variance (ANOVA) and means were compared by the Least Significance Difference (LSD) test (5%). It was verified that shifting the temperature from 5 to 10 degrees C had no significant effect on the physical and chemical variables analyzed. The utilization of atmospheres 3% 0, + 10% CO2 and 3% O-2+ 15% CO2 was important for quality maintenance of fresh-cut strawberries. They better preserved firmness in relation to ambient atmosphere, and had a positive effect on the control of fruit weight loss. However, fresh-cut fruits kept under those atmospheres showed a lower content of anthocyanins when compared to fruits stored in ambient conditions.28227428

    X-ray emission from the Sombrero galaxy: discrete sources

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    We present a study of discrete X-ray sources in and around the bulge-dominated, massive Sa galaxy, Sombrero (M104), based on new and archival Chandra observations with a total exposure of ~200 ks. With a detection limit of L_X = 1E37 erg/s and a field of view covering a galactocentric radius of ~30 kpc (11.5 arcminute), 383 sources are detected. Cross-correlation with Spitler et al.'s catalogue of Sombrero globular clusters (GCs) identified from HST/ACS observations reveals 41 X-rays sources in GCs, presumably low-mass X-ray binaries (LMXBs). We quantify the differential luminosity functions (LFs) for both the detected GC and field LMXBs, whose power-low indices (~1.1 for the GC-LF and ~1.6 for field-LF) are consistent with previous studies for elliptical galaxies. With precise sky positions of the GCs without a detected X-ray source, we further quantify, through a fluctuation analysis, the GC LF at fainter luminosities down to 1E35 erg/s. The derived index rules out a faint-end slope flatter than 1.1 at a 2 sigma significance, contrary to recent findings in several elliptical galaxies and the bulge of M31. On the other hand, the 2-6 keV unresolved emission places a tight constraint on the field LF, implying a flattened index of ~1.0 below 1E37 erg/s. We also detect 101 sources in the halo of Sombrero. The presence of these sources cannot be interpreted as galactic LMXBs whose spatial distribution empirically follows the starlight. Their number is also higher than the expected number of cosmic AGNs (52+/-11 [1 sigma]) whose surface density is constrained by deep X-ray surveys. We suggest that either the cosmic X-ray background is unusually high in the direction of Sombrero, or a distinct population of X-ray sources is present in the halo of Sombrero.Comment: 11 figures, 5 tables, ApJ in pres

    Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

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    The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO

    Performance of CMS muon reconstruction in pp collision events at sqrt(s) = 7 TeV

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    The performance of muon reconstruction, identification, and triggering in CMS has been studied using 40 inverse picobarns of data collected in pp collisions at sqrt(s) = 7 TeV at the LHC in 2010. A few benchmark sets of selection criteria covering a wide range of physics analysis needs have been examined. For all considered selections, the efficiency to reconstruct and identify a muon with a transverse momentum pT larger than a few GeV is above 95% over the whole region of pseudorapidity covered by the CMS muon system, abs(eta) < 2.4, while the probability to misidentify a hadron as a muon is well below 1%. The efficiency to trigger on single muons with pT above a few GeV is higher than 90% over the full eta range, and typically substantially better. The overall momentum scale is measured to a precision of 0.2% with muons from Z decays. The transverse momentum resolution varies from 1% to 6% depending on pseudorapidity for muons with pT below 100 GeV and, using cosmic rays, it is shown to be better than 10% in the central region up to pT = 1 TeV. Observed distributions of all quantities are well reproduced by the Monte Carlo simulation.Comment: Replaced with published version. Added journal reference and DO

    Azimuthal anisotropy of charged particles at high transverse momenta in PbPb collisions at sqrt(s[NN]) = 2.76 TeV

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    The azimuthal anisotropy of charged particles in PbPb collisions at nucleon-nucleon center-of-mass energy of 2.76 TeV is measured with the CMS detector at the LHC over an extended transverse momentum (pt) range up to approximately 60 GeV. The data cover both the low-pt region associated with hydrodynamic flow phenomena and the high-pt region where the anisotropies may reflect the path-length dependence of parton energy loss in the created medium. The anisotropy parameter (v2) of the particles is extracted by correlating charged tracks with respect to the event-plane reconstructed by using the energy deposited in forward-angle calorimeters. For the six bins of collision centrality studied, spanning the range of 0-60% most-central events, the observed v2 values are found to first increase with pt, reaching a maximum around pt = 3 GeV, and then to gradually decrease to almost zero, with the decline persisting up to at least pt = 40 GeV over the full centrality range measured.Comment: Replaced with published version. Added journal reference and DO
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