965 resultados para Spray chilling
Resumo:
This study was carried out with one of the most important cultivar grown in the State of Sao Paulo, Brazil, which has gained the preference of consumers, due to its sweet taste, intense skin color and large size; however, these fruits are susceptible to chilling injury when cold stored for long periods. The use of controlled atmosphere (CA) with elevated CO2 and reduced O2 concentrations prevent the onset of the chilling symptom. Thus, the effect of three different conditions of controlled atmosphere (CA1, CA2, CA3 and Control) was evaluated in order to extend the storage life of 'Douradão' peaches. After 14, 21 and 28 days, samples were withdrawn from CA and kept in fresh air at 25 ± 1 °C and 90 ± 5% RH to complete ripening. On the day of removal and after 4 days, were the peaches quality characteristics were evaluated. The results showed that the use of CA during cold storage reduced weight loss and prevented postharvest decay. CA2 and CA3 treatments were effective in keeping good quality of 'Douradão' peaches during 28 days of cold storage, the ripe fruits showed reduced incidence of woolliness, adequate juiciness and flesh firmness. CA1 and Control treatments did not present marketable conditions after 14 days of cold storage.
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The sensory quality of 'Douradão' peaches cold stored in three different conditions of controlled atmosphere (CA1, CA2, CA3 and Control) was studied. After 14, 21 and 28 days of cold storage, samples were withdrawn from CA and kept for 4 days in ambient air for ripening. The sensory profile of the peaches and the descriptive terminology were developed by methodology based on the Quantitative Descriptive Analysis (QDA). The panelists consensually defined the sensory descriptors, their respective reference materials and the descriptive evaluation ballot. Fourteen panelists were selected based on their discrimination capacity and reproducibility. Seven descriptors were generated showing similarities and differences between samples. The data were analyzed by ANOVA, Tukey test and Principal Component Analysis (PCA). Results showed significant differences in the sensory profiles of the peaches. The PCA showed that CA2 and CA3 treatments were more characterized by the fresh peach flavor, fresh peach appearance, juiciness and flesh firmness, and were effective in keeping the good quality of the 'Douradão' peaches during the 28 days of cold storage. The Control and CA1 treatments were characterized by the mealiness and were ineffective for quality maintenance of the fruits during cold storage.
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Cheese whey permeate was used as a substrate for the fermentation of Propionibacterium freudenreichi PS1 for the production of short chain fatty acids, components of the bio-aroma of Swiss cheese. The liquid bio-aroma was encapsulated by spray drying under different conditions of air inlet temperature and feed rate. A study was carried out on the stability of the bio-aroma during storage in laminated packages at 30 °C for 96 days using the product showing the greatest retention of acetic and propionic acids. The results showed that the best drying conditions were an air entrance temperature of 180 °C and a feed rate of 24 g/min resulting in particles with a smooth surface and few invaginations and micro-fissures. However, 72% of the acetic acid and 80% of the propionic acid were lost during storage showing that the wall material used was inadequate to guarantee product stability.
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Baru (Dipteryx alata Vog.), a species of legume found in the Brazilian savannas, was investigated in this study for the composition of its flesh and seed. Thermal analyses, Thermogravimetry (TG), and Differential Scanning Calorimetry (DSC) were used to investigate the proteins in defatted meal, concentrate, and protein isolate. The protein concentrate was extracted at pH 10, followed by a precipitation at the isoelectric point to obtain the isolate that was spray dried. The thermogravimetric curves were obtained under a nitrogen atmosphere with a 100 mL/minutes flow. The initial, final and peak temperatures and mass loss were analyzed. Within the performed temperature ranges studied, the defatted meal and concentrate presented four steps of mass loss, while the isolate showed only two steps. The protein content of defatted meal from Baru nuts was higher than that of the isolate. On the other hand, there was a reduction in enthalpy, which suggests that the process applied to obtain the baru concentrate and isolate led to protein denaturation.
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Restructuring by adding Sodium Alginate or Microbial Transglutaminase (MTGase) using cold gelation technology make it possible to obtain many different raw products from minced and/or chopped fish muscle that are suitable for being used as the basis of new restructured products with different physicochemical properties and even different compositions. Special consideration must be given to their shelf-life and the changes that may take place during chilling, both in visual appearance and physicochemical properties. After chilled storage, the restructured models made with different muscular particle size and composition at low temperature (5 °C), it was observed that microbial growth limited the shelf-life to 7-14 days. Mechanical properties increased (p < 0.05) during that time, and higher values were observed in samples elaborated by joining small muscle particle size than in those elaborated by homogenization. There was no clear increase in the cooking yield and purge loss, and no significant colour change (p > 0.05) was detected during storage.
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The objective of this study was to obtain babassu coconut milk powder microencapsulated by spray drying process using gum Arabic as wall material. Coconut milk was extracted by babassu peeling, grinding (with two parts of water), and vacuum filtration. The milk was pasteurized at 85 ºC for 15 minutes and homogenized to break up the fat globules, rendering the milk a uniform consistency. A central composite rotatable design with a range of independent variables was used: inlet air temperature in the dryer (170-220 ºC) and gum Arabic concentration (10-20%, w/w) on the responses: moisture content (0.52-2.39%), hygroscopicity (6.98-9.86 g adsorbed water/100g solids), water activity (0.14-0.58), lipid oxidation (0.012-0.064 meq peroxide/kg oil), and process yield (20.33-30.19%). All variables influenced significantly the responses evaluated. Microencapsulation was optimized for maximum process yield and minimal lipid oxidation. The coconut milk powder obtained at optimum conditions was characterized in terms of morphology, particle size distribution, bulk and absolute density, porosity, and wettability.
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The focus of the work reported in this thesis was to study and to clarify the effect of polyelectrolyte multilayer surface treatment on inkjet ink spreading, absorption and print quality. Surface sizing with a size press, film press with a pilot scale coater, and spray coating, have been used to surface treat uncoated wood-free, experimental wood-free and pigmentcoated substrates. The role of the deposited cationic (polydiallydimethylammonium chloride, PDADMAC) and anionic (sodium carboxymethyl cellulose, NaCMC) polyelectrolyte layers with and without nanosilica, on liquid absorption and spreading was studied in terms of their interaction with water-based pigmented and dye-based inkjet inks. Contact angle measurements were made in attempt to explain the ink spreading and wetting behavior on the substrate. First, it was noticed that multilayer surface treatment decreased the contact angle of water, giving a hydrophilic character to the surface. The results showed that the number of cationic-anionic polyelectrolyte layers or the order of deposition of the polyelectrolytes had a significant effect on the print quality. This was seen for example as a higher print density on layers with a cationic polyelectrolyte in the outermost layer. The number of layers had an influence on the print quality; the print density increased with increasing number of layers, although the increase was strongly dependent on ink formulation and chemistry. The use of nanosilica clearly affected the rate of absorption of polar liquids, which also was seen as a higher density of the black dye-based print. Slightly unexpected, the use of nanosilica increased the tendency for lateral spreading of both the pigmented and dye-based inks. It was shown that the wetting behavior and wicking of the inks on the polyelectrolyte coatings was strongly affected by the hydrophobicity of the substrate, as well as by the composition or structure of the polyelectrolyte layers. Coating only with a cationic polyelectrolyte was not sufficient to improve dye fixation, but it was demonstrated that a cationic-anionic-complex structure led to good water fastness. A threelayered structure gave the same water fastness values as a five-layered structure. Interestingly, the water fastness values were strongly dependent not only on the formed cation-anion polyelectrolyte complexes but also on the tendency of the coating to dissolve during immersion in water. Results showed that by optimizing the chemistry of the layers, the ink-substrate interaction can be optimized.
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Korkean IP-luokituksen ohutlevykotelointi on haastava kokonaisuus. Koteloinnin tiivistys ruiskutettavalla polyureapinnoitteella edellyttää usean osa-alueen samanaikaista hallintaa. Kotelo on alusta alkaen suunniteltava pinnoitettavaksi, sillä pinnoitus asettaa lukuisia vaatimuksia ja rajoituksia esimerkiksi käytettäville muodoille, rakenteille ja liittämismenetelmille. Polyurea on elastomeeri, josta valmistettua pinnoitetta voidaan levittää erityisellä ruiskutuslaitteistolla. Polyureapinnoite sallii kotelon asentamisen vaikeisiin olosuhteisiin, sillä se kestää kemikaaleja, kulutusta ja iskuja sekä tarjoaa tiiveyden lisäksi korroosiosuojan koteloinnille. Pinnoitteen ominaisuuksia, kuten kovuutta, elastisuutta ja kemikaalien sekä UV-säteilyn kestoa voidaan räätälöidä käyttökohteen mukaan. Polyurepinnoitteeella pinnoitettavat pinnat on pyrittävä pitämään mahdollisimman yksinkertaisina, mikä tarkoittaa käytännössä kaikenlaisten kohoumien, ulkonevien osien, reikien ja muiden epäjatkuvuuskohtien välttämistä. Kaikki epäjatkuvuuskohdat vaativat erityishuomiota pinnoituksen aikana, sillä epäjatkuvuuskohtien onnistunut pinnoitus vaatii ruiskutusta useasta suunnasta, mikä lisää virhemahdollisuuksia ja siten vaarantaa koteloinnin tiiveyden. Liittämismenetelmät ovat yksinkertaisten muotojen ohella avainasemassa pinnoituksen onnistumisen kannalta. Menetelmistä tulee suosia sellaisia, joiden pinnoitettavaan pintaan aiheuttama epäjatkuvuuskohta on mahdollisimman vähäinen. Tällaisia menetelmiä ovat esimerkiksi vastuspistehitsaus ja puristeruuvi.
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Graffiti, Memory and Contested Space: Mnemonic Initiatives Following Periods of Trauma and/or Repression in Buenos Aires, Argentina This thesis concerns the popular articulation ofmemory following periods or incidents of trauma in Argentina. I am interested in how groups lay claim to various public spaces in the city and how they convert these spaces into mnemonic battlegrounds. In considering these spaces of trauma and places of memory, I am primarily interested in how graffiti writing (stencils, spray-paint, signatures, etchings, wall-paintings, murals and installations) is used to make these spaces transmit particular memories that impugn official versions of the past. This thesis draws on literatures focused on popular/public memory. Scholars argue that memory is socially constructed and thus actively contested. Marginal initiatives such as graffiti writing challenge the memory projects of the state as well as state projects that are perceived by citizens to be 'inadequate,' 'inappropriate,' and/or as promoting the erasure of memory. Many of these initiatives are a reaction to the proreconciliation and pro-oblivion strategies of previous governments. I outline that the history of silences and impunity, and a longstanding emphasis on reconciliation at the expense of truth and justice has created an environment of vulnerable memory in Argentina. Popular memory entrepreneurs react by aggressively articulating their memories in time and in space. As a result of this intense memory work, the built landscape in Buenos Aires is dotted with mnemonic initiatives that aim to contradict or subvert officially sanctioned memories. I also suggest that memory workers in Argentina persistently and carefially use the sites of trauma as well as key public spaces to ensure official as well as popular audiences . The data for this project was collected in five spaces in Buenos Aires, the Plaza de Mayo, Plaza Congreso, La Republica Cromanon nightclub, Avellaneda Train Station and El Olimpo, a former detention centre from the military dictatorship.
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Studies on persistence and degradation of the synthetic pyrethroid insecticides, permethrin and fenvalerate, were carried out under natural environmental conditions of the Niagara Peninsula. Permethrin and fenvalerate were treated on apple foliage atrat~s of 0.21 kg(AI)!ha and 0.14 kg(AI)/ha, respectively. The initial cis- and trans-permethrin spray deposits were found to be 13.5 ppm and 19.2 ppm, respectively and 38.0 ppm was observed for the fenvalerate treated sample. Twenty-three days and 84 days after spray application, permethrin residues were 4.0 ppm and 2.7 ppm for the cis-isomer, whereas they were 7.9 ppm and 4.7 ppm for the trans-isomer, respectively. Residues of fenvalerate 23 days and 84 days after spray application were 13.4 ppm and 8.0 ppm, respectively. The values of observed half-life of cis-permethrin, trans-permethrin and fenvalerate were found to be 42 days, 46 days and 51 days, respectively. Studies were extended to quantitatively determine some of the major degradation compounds of permethrin and fenvalerate, which were expected to be produced as results of ester cleavage of the parent compounds. A permethrin treated sample, 84 days after initial spray application, showed 0.25 and 0.8 ppm of cis- and trans-3-(2,2-dichlorovinyl)-2,2-dimethylcyclopropanecarboxylic acid (C12CA (18), respectively. These two acids were not found as free acids, but found as conjugated compounds. The other expected degradation compounds, 3-phenoxybenzyl alcohol (PBalc (~)),3-phenoxybenz.aldehyde (PBald (38)) and 2- (4-chlorophenyl) isovaleric acid (CPIA (31)) were not detected by the methods employed in this study. The results indicate that these degradation compounds were not present, or, if they were present, their concentrations were too low to detect by the methods used.
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A simple High Performance Liquid Chromatograph (HPLC) method has been developed to identify benamyl (methyl 1- (butylcarbamoyl)-2-benzimidazole carbamate) and MBC (methyl 2-benzimidazole carbamat~ residues on apple leaves without cleanup. Sample leaves are freeze dried in a Mason jar and residues are then extracted by tumbling them in chloroform containing 5,000 microgram per milliliter of n-propyl isocyanate (PIC) at 10 C. To the extract, n-butyl isocyanate (BIC) was added at 5,000 microgram per milliliter and 20 microliter of this mixture injected onto the HPLC system. Separation is accomplished by the use of a Brownlee LiChrosorb silica gel column with a guard column and' operated with a mixed mobile phase consisting of chloroform and hexane (4:1) saturated with water. MBC, a degradation product of benomyl is identified if present as methyl l-(npropyl carbamoyl)-2-benzimidazole carbamate (MBC-n-PIC). Both benomyl and MBC-n-PIC can be detected with aKUltraviolet (UV) detector (280nm) at a concentration as low as 0.2 microgram per milliliter in apple leaves. The fate of benomyl on apple foliage after spray application of benomyl (Ben late 50 per cent wettable powder) was investigated by the method thus described. Benomyl quickly dissipated during the first 3-7 days, but the dissipatio'n sltowed down thereafter. In contrast, the concentration of MBC in leaves gradually increased after repeated applications of Benlate.
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A simple, low-cost concentric capillary nebulizer (CCN) was developed and evaluated for ICP spectrometry. The CCN could be operated at sample uptake rates of 0.050-1.00 ml min'^ and under oscillating and non-oscillating conditions. Aerosol characteristics for the CCN were studied using a laser Fraunhofter diffraction analyzer. Solvent transport efficiencies and transport rates, detection limits, and short- and long-term stabilities were evaluated for the CCN with a modified cyclonic spray chamber at different sample uptake rates. The Mg II (280.2nm)/l\/lg 1(285.2nm) ratio was used for matrix effect studies. Results were compared to those with conventional nebulizers, a cross-flow nebulizer with a Scott-type spray chamber, a GemCone nebulizer with a cyclonic spray chamber, and a Meinhard TR-30-K3 concentric nebulizer with a cyclonic spray chamber. Transport efficiencies of up to 57% were obtained for the CCN. For the elements tested, short- and long-term precisions and detection limits obtained with the CCN at 0.050-0.500 ml min'^ are similar to, or better than, those obtained on the same instrument using the conventional nebulizers (at 1.0 ml min'^). The depressive and enhancement effects of easily ionizable element Na, sulfuric acid, and dodecylamine surfactant on analyte signals with the CCN are similar to, or better than, those obtained with the conventional nebulizers. However, capillary clog was observed when the sample solution with high dissolved solids was nebulized for more than 40 min. The effects of data acquisition and data processing on detection limits were studied using inductively coupled plasma-atomic emission spectrometry. The study examined the effects of different detection limit approaches, the effects of data integration modes, the effects of regression modes, the effects of the standard concentration range and the number of standards, the effects of sample uptake rate, and the effect of Integration time. All the experiments followed the same protocols. Three detection limit approaches were examined, lUPAC method, the residual standard deviation (RSD), and the signal-to-background ratio and relative standard deviation of the background (SBR-RSDB). The study demonstrated that the different approaches, the integration modes, the regression methods, and the sample uptake rates can have an effect on detection limits. The study also showed that the different approaches give different detection limits and some methods (for example, RSD) are susceptible to the quality of calibration curves. Multicomponents spectral fitting (MSF) gave the best results among these three integration modes, peak height, peak area, and MSF. Weighted least squares method showed the ability to obtain better quality calibration curves. Although an effect of the number of standards on detection limits was not observed, multiple standards are recommended because they provide more reliable calibration curves. An increase of sample uptake rate and integration time could improve detection limits. However, an improvement with increased integration time on detection limits was not observed because the auto integration mode was used.
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There is a body of academic literature addressing two issues of importance for leveling the playing field for all classes of investors: 1) the impact of institutional investors on liquidity; and 2) the impact of Regulation Fair Disclosure on institutional investors and liquidity. Our study addresses both issues with the purpose of attaining a better understanding and explanation of this relationship. We classify institutional ownership according to Bushee's (1998, 2001) methodology; transient institutions, dedicated institutions and quasi-indexers. Our results indicate that while transient institutions and quasi-indexers have a positive impact on liquidity, dedicated institutional ownership is negatively associated with liquidity. This result is consistent with prior theoretical studies. We also find that the effectiveness ofthe Regulation Fair Disclosure in improving liquidity is limited to firms with higher transient institutional ownership, whereas quasi-indexed institutions have not been significantly affected by the regulations. In fact, the liquidity of firms is lower for firms with higher dedicated institutional holdings, which is evidence of the "chilling effect".
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The image is described as "(7) Niagara and its great cloud of rising Spray - from the distant tower, U.S.A.".
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The description of the image is "(6) Majestically Grand - the Falls from the 'Maid of the Mist,' Niagara, U.S.A.". The reverse of the image reads "You are on the deck of the small but sturdy little steamer that runs along near the foot of the falls. At this moment you are pretty nearly mid-stream, looking south. The American shore are up over your left shoulder. That tall, dark cliff at the extreme left of what you see is Goat Island. The people up there outlined against the sky look like dolls and no wonder; they are more than 160 feet above your head. Some of them are looking off over the unspeakable grandeurs of the Horseshoe Fall there at the right; some are without doubt looking down at the very boat and remarking that the passengers look like dolls. It is an awesome experience to go so near that never-ceasing downpour of waters from the sky. The air is full of the roar and iridescent spray, and it seems as if the boat must be drawn in under the overwhelming floods never to rise again. Yet, curiously enough, the river right around the boat is not so madly excited as you might expect. It seems more like some great creature, dazed, bewildered, stunned by some incredible experience and not yet quite aware of what has happened. (When it gets down into the Whirlpool Rapids, two miles below here, it is dramatically alive to its situation!) The gigantic curve of the cliffs, reaching in up-stream straight ahead, makes a contour line of over 3000 feet before it comes up against the Canadian banks on the west (right). Geologists say that the Falls ages ago must have been at least seven miles farther down the river (behind you) and have gradually won their way back. Even now the curve of the Horseshoe is worn away from two to four feet in a year. No wonder; 12, 000, 000 cubic feet of water (about 375, 000 tons) sweep over the rocks in one minute, and the same the next minute and the next and the next. See Niagara through the Stereoscope, with special maps locating all the landmarks about the Falls.