Men de Sá Moreira de Souza Filho

Extraction and characterization of nanocellulose structures from raw cotton linter

This study aimed to characterize nanocellulose extracted from cotton (Gossypium hirsutum) linters. The nanocellulose was subjected to electronic microscopy, thermal analysis, X-ray diffractometry, light scattering, and contact angle. The properties of the nanocellulose are considerably different from the linter. The acidic hydrolyses applied to extract the nanocrystals increased the crystallinity index and the hydrophilicity and decreased the thermal stability. On average, the nanocrystals were 177 nm long and 12 nm wide, with an aspect ratio of 19 when measured by microscopy. The light scattering results were coherent with the crystal dimensions. Cotton linter is a potential source of nanocellulose crystals, particularly to be used in the production of hydrophilic nanocomposites. Extraction of nanocellulose from raw cotton linter does not require pulping.

Bacterial cellulose nanocrystals produced under different hydrolysis conditions: properties and morphological features

Bacterial cellulose (BC) is a polymer with interesting physical properties owing to the regular and uniform structure of its nanofibers, which are formed by amorphous (disordered) and crystalline (ordered) regions. Through hydrolysis with strong acids, it is possible to transform BC into a stable suspension of cellulose nanocrystals, adding new functionality to the material. The aim of this work was to evaluate the effects of inorganic acids on the production of BC nanocrystals (BCNCs). Acid hydrolysis was performed using different H2SO4 concentrations and reaction times, and combined hydrolysis with H2SO4 and HCl was also investigated. The obtained cellulose nanostructures were needle-like with lengths ranging between 622 and 1322nm, and diameters ranging between 33.7 and 44.3nm. The nanocrystals had a crystallinity index higher than native BC, and all BCNC suspensions exhibited zeta potential moduli greater than 30mV, indicating good colloidal stability. The mixture of acids resulted in improved thermal stability without decreased crystallinity.

Storage stability of cashew apple juice preserved by hot fill and aseptic processes

Cashew (Anacardium occidentale L.) apples from Pacajus, Ceara State, Brazil, were processed into high pulp content juice. The juice was packed either by hot fill or an aseptic process and evaluated for physical, physical-chemical, and sensorial changes during a 12-month storage period at room temperature. The results indicated that pH, soluble solids, total acidity, total sugar content and color did not change significantly during storage nor were affected by the type of filling. The sensorial analysis showed that juice acceptance remained high throughout the storage period regardless of the filling system. Differences in juice viscosity persisted between both processes.

DESIDRATAÇÃO DA POLPA DE ACEROLA (Malpighia emarginata D.C.) PELO PROCESSO "FOAM-MAT"

A food supplement from dehydrated pulp using a non-conventional method of FOAM-MAT was produced. Several tests have been accomplished using different chemical agents to facilitate the foam formation, and an experiment has been chosen that most adjusted to the recommended density parameter (0.1 to 0.6). After the definition of the experimental conditions, the pulp was formulated and dehydrated in a drying hot-house with air circulation at a temperature of 60 to 70°C for 90 minutes. The product obtained was a powder with final humidity of 7.2%. Concomitant to the experiment the chemical analysis of the pulp had been accomplished. The obtained powder was immediately afterwards analysed with the purpose of identifying the new characteristics of the product and packed in 25g metalized bags and submitted to stability studies for a period of 3 months. Analysis of the results obtained showed that there was an increase in the basic nutrients mainly regarding to the content of vitamin C that showed an increase 10 times higher than natural pulp.

Processamento e conservação de manga por métodos combinados

A tecnologia de metodos combinados foi empregada na conservacao da manga (Mangifera indica, L.) em pedacos. A estabilidade fisico-quimica, microbiologica e sensorial da manga em pedacos foi obtida atraves do branqueamento com vapor saturado por 2 min, ajuste da atividade de agua (Aw) para 0,97, do pH para 3,6, adicao de 600 ppm de acido ascorbico, 1000 ppm de benzoato de sodio e 600 ou 900 ppm de dioxido de enxofre. Os produtos da manga processados nas condicoes descritas apresentaram, ao longo de 120 dias de armazenamento, teores de umidade, atividades de agua e pH na faixa para produtos de fruta de alta umidade; aumento dos acucares redutores; acentuada perda de SO2 (cerca de 60%) e vitamina C; reducao da contagem microbiologica, demonstrando que a selecao de obstaculos e suas intensidades foram capazes de assegurar a estabilidade microbiologica do produto. O teste de aceitabilidade mostrou que a manga conservada por metodos combinados teve boa aceitacao e que as medias dos atributos se assemelham aos resultados de testes sensoriais mencionados na literatura.

Influência da concentração e da proporção fruto: xarope na desidratação osmótica de bananas processadas

Considering the technological limitations of the traditional processes for production of banana fig with standard quality, the osmotic dehydration appears as an option to the standardization of this process. In this work to determine parameters of the banana osmotic dehydration process and to evaluate the influence of osmotic solution concentration on the physical chemical caracteristics of the fruit and stablish drying curves of pre treatment bananas through osmotic dehydration with and without vacuum. It was concluded that is possible to obtain dehydrated banana as a product of intermediate moisture, through osmotic pre treatment followed by drying. The characteristics of the product were influenced by concentration and proportion fruit:xyrop of the used medium.

Desidratação osmótica de manga seguida de secagem convencional: avaliação das variáveis de processo

A manga e uma fruta muito popular dos tropicos, consumida principalmente na forma in natura e com grandes possibilidades de industrializacao. A desidratacao osmotica seguida de secagem convencional tem se apresentado como uma ferramenta tecnologica importante no desenvolvimento de novos produtos, viabilizando o aproveitamento e valorizacao da manga. O presente trabalho teve como objetivo avaliar a influencia da concentracao do xarope osmotico e da pressao do sistema sobre a cinetica de desidratacao osmotica da manga, assim como sobre o processo de secagem subsequente. Verificou-se durante todo o processo a influencia das variaveis estudadas, notadamente da utilizacao de vacuo que possibilitou a reducao do tempo total de processo.

Microbiological, physico-chemical and sensorial stability of cashew apples (Anacardium occidentale L.) processed by combined methods

Cashew apples processed by combined methods were stored at room temperature (28oC) in order to evaluate the tendency for chemical, microbiological and sensorial changes during 120 days of storage. Results confirmed that the obstacles used (reduction of water activity, mild heat treatment, pH reduction, ascorbic acid addition, 1000ppm sodium benzoate, 600 and 900ppm of SO2) and their intensities were capable to assure the microbiological stability and sensorial acceptance of the product during storage stability at room temperature for 120 days.

Shelf life of minimally processed pineapples treated with ascorbic and citric acids

Abstract The purpose of this research was to determine the shelf life of minimally processed (MP) ‘Perola’ pineapples treated with ascor -bic acid (AA) and citric acid (CA) based on physical, chemical, sensorial and microbiological attributes. Slices were dipped into drinking water (control) or combined solutions of AA:CA (%) (1.0:0.5 and 1.0:1.0) with sodium hypochlorite (NaClO 20 mg L –1 ) for 30 seconds. The samples were conditioned in polyethylene terephtalate packages and stored at 4±1 °C per 13 days. The low peroxidase activity in the slices treated with antioxidant combinations was related to low pH values observed in these samples. The treatments 1.0:0.5 and 1.0:1.0 (AA:CA, %) favored maintenance of the initial a* values and avoided the pulp browning. The ascorbic acid increased more than double on the 2 nd day in the treated slices. By the 4 th day the CO 2 values suggested a higher respiratory activity in the slices treated with anti-browning compounds. The antioxidant treatments did not produce detectable residual flavors in the MP pineapple. Regardless of microbiological safety during the 13 days of cold storage, the control slices can be kept by 6 days, afterwards the color and dehydration become strong enough to affect the appearance. On the other hand, MP ‘Perola’ pineapples treated with 1.0:0.5 (AA:CA, %) and NaClO (20 mg L

Influência da adição de sacarose na estabilidade da polpa de bacuri conservada por métodos combinados

O estudo do processo de conservacao da polpa de bacuri (Platonia insignis Mart.), atraves da aplicacao da tecnologia de obstaculos, foi feito pela combinacao dos seguintes fatores: adicao de benzoato de sodio (1000 ppm) e metabissulfito de sodio (400 ppm), tratamento termico (100oC/2 min.) e reducao da atividade de agua pela adicao de sacarose (0, 17,4 e 28,6% (p/p)). A estabilidade dos produtos foi avaliada segundo suas caracteristicas fisico-quimicas, microbiologicas e sensoriais, a cada 30 dias, durante quatro meses de armazenamento, a temperatura ambiente (25oC±2oC). As caracteristicas fisico-quimicas dos produtos obtidos sofreram pouca alteracao durante o armazenamento, sendo os teores de acucares redutores e o teor de dioxido de enxofre as caracteristicas mais afetadas nos tres produtos. Os resultados mostraram que os tipos de obstaculos usados e sua intensidade foram capazes de assegurar a estabilidade microbiologica e uma boa aceitacao sensorial dos produtos durante o periodo de armazenamento.