a b s t r a c tThe aim of this study was the production and characterization of gelatin-based films using hydrophobic plasticizers derived from citric acid and soy lecithin as emulsifier. The films were characterized as to their mechanic properties, permeability to water vapor, opacity, morphology and possible interactions using Fourier transform infrared spectroscopy. Tensile strength values (TS) varied from 36 to 103 MPa, however, the increase in the concentration of plasticizers (acetyltributyl citrate and tributyl citrate) reduced TS by 57% and no relation was observed between plasticizer quantities and the elongation in the quantities tested. Permeability to water vapor varied between 0.17 and 0.34 (g mm/m 2 h kPa), slightly increasing with the increase in concentration of plasticizers. The effectiveness in the use of soy lecithin emulsifier in the homogenization between the compounds could be proven by microscopic observation using confocal laser microscopy.
a b s t r a c tThe aim of this research was to evaluate the plasticizing effect of natural surfactants lecithin or yucca extract from Yucca schidigera on gelatin-based films. Films containing yucca extract showed higher tensile strength values ($90-40 MPa) and moisture contents ($15%) and less elongation ($5%) and water vapor permeability values ($0.22-0.09 g mm m À2 h À1 kPa À1 ) compared to films containing lecithin. Soluble films ($20-50%) were obtained when yucca extract was used while lecithin produced low soluble films (<10%). The opacity of the films ($14.5-16.2%) was similar for both surfactants and the film surface morphologies were continuous and homogeneous. X-ray diffraction indicated that the addition of surfactants produced amorphous films compared to gelatin-based films and FT-Infrared spectroscopy showed no evidence of association between the surfactants and the gelatin. The plasticizing effect was not obtained after surfactants addition and casting technique.
a b s t r a c tGelatin-based films containing both Yucca schidigera extract and low concentrations of glycerol (0.25-8.75 g per 100 g protein) were produced by extrusion (EF) and characterized in relation to their mechanical properties and moisture content. The formulations that resulted in either larger or smaller elongation values were used to produce films via both blown extrusion (EBF) and casting (CF) and were characterized with respect to their mechanical properties, water vapor permeability, moisture content, solubility, morphology and infrared spectroscopy. The elongation of the EF films was significantly higher than that of the CF and EBF films. The transversal section possessed a compact, homogeneous structure for all of the films studied. The solubility of the films (36-40%) did not differ significantly between the different processes evaluated. The EBF films demonstrated lower water vapor permeability (0.12 g mm m À2 h À1 kPa À1 ) than the CF and EF films. The infrared spectra did not indicate any strong interactions between the added compounds. Thermoplastic processing of the gelatin films can significantly increase their elongation; however, a more detailed assessment and optimization of the extrusion conditions is necessary, along with the addition of partially hydrophobic compounds, such as surfactants.
a b s t r a c tThe aim of this study was to evaluate the incorporation of hydrophobic plasticizers (acetyltributyl citrate -ATB, tributyl citrate -TB and acetyltriethyl citrate -ATC) in a matrix of gelatin, using the saponin extracted from Yucca schidigera (yucca) as emulsifier, in the production of biodegradable emulsified films using the casting technique. High levels of hydrophobic plasticizers were incorporated, reaching up to 75% of plasticizer in relation to the protein (w/w) for ATB and TB, and up to 60% for ATC. The minimum values of water vapor permeability were 0.08, 0.07 and 0.06 g mm m À2 h À1 kPa À1 for ATB, TB and ATC respectively, with no significant differences (p > 0.05). The water solubility of the films ranged from 21% to 59.5%. Although the WVP decreased, both scanning electron microscopy and laser scanning confocal microscopy indicated that the incorporation of the hydrophobic plasticizers did not occur homogeneously in the film matrix.
economia e extensão rural O s consumidores sinalizam a estratégia de mercado para melhoria na apresentação do produto, a ser adotada pelas empresas do setor alimentício e produtores agrícolas. Sabe-se que a satisfação ou não do consumidor pode interferir em decisões de compras futuras (Marcos, 2000). O consumidor busca qualidade e comodidade, procurando produtos frescos, com bons preços, além de um ambiente seguro e disponível em seu horário livre (Frutas, 1996). Kotler (1998) relata que a satisfação do consumidor é função das expectativas atendidas no momento da compra. Se o desempenho do produto adquirido se afasta das expectativas, o consumidor conseqüentemente estará insatisfeito. Caso contrário, se o desempenho atender às expectativas, o consumidor estará satisfeito e dessa maneira com grandes possibilidades de manter a fidelidade do consumidor em relação ao produto adquirido. Nos últimos anos, a participação dos supermercados na distribuição e venda de hortaliças tem crescido no Brasil e no mundo e para ser competitivo e atender a demanda é necessário compreender o consumidor, traçar seu perfil e conhecer seus hábitos (Saabor, 2001).Kader (2002), relata que o consumidor de frutas e hortaliças avalia primeiramente a cor deste e posteriormente a sua textura, e como o cliente não tem acesso à visualização do interior do fruto, usa sua experiência anterior para avaliar o produto. Desde a década dos anos setenta os consumidores estão insatisfeitos com o preço e a qualidade do RESUMOO acesso a informações e às mudanças tecnológicas fizeram com que consumidores se tornassem cada vez mais exigentes e preocupados com a saúde. Assim, procurou-se estabelecer o comportamento de compra dos consumidores de tomate de mesa (Lycopersicon esculentum Mill.) em supermercados de Campinas (SP), e a partir das respostas aos questionários traçou-se seu perfil destacando suas preferências, costumes, reclamações e exigências. Identificou-se que é a mulher que realiza as compras para casa, com preferência pelo consumo do tomate na forma "in natura". Encontrou-se insatisfação de 95,6% dos entrevistados quanto à qualidade do tomate, sendo a presença de danos físicos a maior reclamação. Assim, a qualidade do tomate que estava sendo apresentado nas gôndolas dos supermercados não correspondia àquela indicada pelos consumidores (frutos com coloração vermelha, uniformes e ausência de injúrias). Diante da insatisfação dos consumidores e considerando que o tomate preferencialmente é consumido "in natura" deve-se atentar para sua aparência externa, promovendo manuseio adequado nas etapas pós-colheita a fim de minimizar danos físicos. Os consumidores revelaram que pagariam uma quantia mais elevada pelo tomate caso este apresentasse melhor qualidade. A opinião do consumidor deve ser considerada para se encontrar soluções tecnológicas e/ou estratégi-cas que possam minimizar os danos pós-colheita do tomate, atingindo suas expectativas quanto à qualidade do produto. Palavras-chave:Lycopersicon esculentum Mill., danos físicos, padrões de qualidade...
Gelatin-based films containing soy lecithin or Yucca schidigera extract and glycerol as plasticizer were produced by casting and characterized for their mechanical properties, water vapor permeability (WVP), water solubility, opacity and morphology. The addition of glycerol reduced the tensile strength, with a difference of ~ 68% between the values for the minimum and maximum concentrations evaluated, both for the plasticizer and the surfactant. Elongation values reached 52% and 40%, for films containing yucca extract and lecithin, respectively, when higher amounts of plasticizer and surfactant were added. Lower values of WVP were obtained when the intermediate concentration of glycerol (20 g plasticizer/100 g protein) was used, reaching 0.14 and 0.15 g mm/m 2 h kPa, respectively, for films containing yucca extract and lecithin. The solubility was not affected by adding plasticizer and / or surfactants. The morphologies of the inner sections of the films, regardless of type of surfactant used, were compact, without pores or phase separation, indicating efficient incorporation of the compounds added to the protein matrix.
O tomate é uma das principais hortaliças cultivadas no Brasil e tratamentos que propiciem o controle do amadurecimento são extremamente desejáveis. Avaliou-se a qualidade pós-colheita de tomates tipo italiano tratados com etileno. Tomates 'Andréa' foram colhidos em campos de produção comercial no estádio verde-maduro, selecionados para presença de danos externos e classificados quanto ao tamanho e cor e posteriormente foram tratados com 100 µL L-1 de etileno. Os ensaios foram planejados com delineamento inteiramente casualizado em esquema fatorial com quatro tratamentos e quinze repetições (n=10). Após a aplicação, os frutos foram divididos em dois lotes. Um lote permaneceu a 20º±1ºC e outro foi mantido a 12,5º±1ºC, ambos sob umidade relativa 90±5%. Tomates do tratamento controle foram mantidos nas mesmas condições de temperatura e umidade relativa. Os frutos foram avaliados após cada mudança de estádio de amadurecimento para as seguintes variáveis: coloração externa (L*a*b*), perda de massa, sólidos solúveis totais, acidez titulável e teor de ácido ascórbico. A aplicação de etileno não influenciou de maneira significativa as variáveis químicas e físicas estudadas. Frutos armazenados à temperatura de 20ºC demonstraram maior porcentagem de perda de massa ao longo do amadurecimento, com média de 2,60%. A relação brix/acidez apresentou pouca variação entre os tratamentos avaliados. Frutos do tratamento controle e mantidos à temperatura de 20ºC apresentaram mudança de coloração mais rápida no início dos experimentos, não sendo observada posteriormente diferença significativa no desenvolvimento da cor dos tratamentos avaliados. O tratamento com etileno não acelerou de forma significativa o amadurecimento de tomates 'Andréa' armazenado sob as duas temperaturas estudadas.
Characterization and commercialization of fresh tomatoes at CEASA: profile of wholesalersThe Terminal Markets are the main centers for distribution of vegetables, fruits and flowers from different States of Brazil. The CEAGESP wholesalers can be shippers or growers. The amount of tomato commercialized in these terminal markets is very expressive. It was possible to determine the profile and the main features of the wholesale market at CEAGESP. About 45.8% of the wholesalers had an average commercialization volume of 10,000 tons/year, and 70.8% of them commercialize their own production. Cultivars Carmen and Débora were the leaders on the market. The results pointed out that wholesalers had more than one type of buyer, and the main ones were street fair and supermarkets. Most of the tomato is commercialized in boxes (box K), followed by 20.8% of plastic boxes and 16.7% of cardboard packages. CEAGESP wholesalers adopt tomato classification, either done manually (58.4%), or by machines (8.3%) or using both systems (33.3%). The standardization index was not satisfactory, with color and sizes in different degrees, and therefore 45.8% has to be reclassified.
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