Acácio Figueiredo Neto

Comportamento mecânico dos grãos de feijão submetidos a compressão

Verificar a influencia do teor de agua nos valores da forca maxima de compressao para deformacoes fixas e determinar o modulo proporcional de deformidade de graos de feijao submetidos a compressao em tres diferentes posicoes, foram os principais objetivos que estimularam o presente trabalho. Para isto, utilizaram-se graos de feijao com teores de agua variando de 0,13 a 0,45 (b.s.) comprimidos uniaxicialmente, entre duas placas paralelas, na direcao de suas tres dimensoes essenciais. A partir dos resultados obtidos, conclui-se que a forca de compressao necessaria para deformar o feijao diminui com o aumento do teor de agua, sendo maior para a direcao perpendicular a divisao dos cotiledones (posicao natural de repouso). O modulo proporcional de deformidade aumenta com a reducao do teor de agua e da deformacao do produto, obtendo-se valores para a faixa de umidade estudada, entre 1,7 x 107 a 71,3 x 107 Pa, dependendo da posicao do grao.

Mechanical behavior of pumpkin fruits subjected to compression during maturation

During handling operations, many problems that reduce the quality of vegetables may occur. Mechanical injuries are the leading cause of postharvest losses for the pumpkin, and can take place at any point of the production chain. This study aimed at evaluating the pumpkin fruits behavior, during their ripening stages, on the values ??of maximum compression force for fixed deformations, and determining the proportional deformability modulus of the fruits under compression at the repose position . Fruits were harvested at 15, 30 , 40 , 50 and 60 days after flowering and uniaxially compressed between two parallel plates . The results allowed to conclude that both the required compression force and the proportional deformability modulus increased during the maturation course, reaching a maximum force of 1,778 N and a maximum deformation modulus of 164 MPa, after 30 days. After this period, both the maximum force and the modulus values ??decreased, reaching 1,514.8 N of maximum force and a modulus of 132.09 MPa, after 60 days of ripening . Over the course of a longer maturation time, the fruit firmness increased, therefore requiring an increase in the maximum load to achieve greater deformation. The ideal period for harvest and transport of ‘Jacarezinho’ pumpkin fruits was set from 30 to 40 days after anthesis.

Mechanical characterization of mango fruit using compression tests

Brazil is one of the largest producers of mangoes, and the São Francisco Valley accounts for about 87% of Brazilian exports of this product to the European market. This study aimed to characterize the mechanical behavior of the fruits according to the maturation stages, in order to prevent physical damage caused by improper handling of the fruit during harvest, storage, processing and transportation. The compression tests were performed on the mango cultivars (Mangifera indica L.) Keitt and Tommy Atkins at different maturation stages in order to characterize the internal elastic modulus and determine the maximum stress until rupture of the sleeve. The fruits showed a decrease in mechanical properties corre‐ lated with the increase of maturation stage, for both cutivars. The Tommy Atkins variety showed better mechanical properties probably related to a higher concentration of fibers in the pulp which yields better mechanical stabilization.

Aspectos físico-químicos e microbiológicos de polpas de frutas comercializadas em Petrolina (PE) e Juazeiro (BA)

This study aimed to evaluate some physical, chemical and microbiological characteristics of frozen fruit pulps marketed in Petrolina (PE/Brazil) and Juazeiro (BA/Brazil). For this purpose seven flavours of four brands (A, B, C and D) of frozen fruit pulps were evaluated for the total number of moulds and yeasts, total coliforms and coliforms heat tolerant at 45 °C (faecal), pH, soluble solids and colour. The results obtained for the same flavour of different brands, with four repetitions, were submitted to an analysis of variance and the means compared using Tukey´s test (5% significance). Furthermore, the results were evaluated based on the Brazilian legislation for each type of fruit pulp. All the brands showed colours and total soluble solids which conformed with the legislation, with minor variations between brands depending on the flavour. The samples of brand C presented high levels of moulds and yeasts for all flavours and pH values different from those established by the Brazilian legislation for mango and cashew pulps. Faecal coliforms were also detected in the brand C pulps. It was concluded that 61.75% of brand C, 14.29% of brand A and 14.29% of brand D frozen fruit pulps were unfit for consumption. The need to establish physical and chemical standards for pineapple and tamarind pulps was also shown.

DETERMINAÇÃO DE VITAMINA C E AVALIAÇÃO FÍSICO-QUÍMICA EM TRÊS VARIEDADES DE ACEROLA CULTIVADAS EM PETROLINA-PE

O cultivo da acerola no Brasil tem se apresentado cada vez mais crescente. Na regiao Nordeste, a cidade de Petrolina-PE, se destaca por produzir o equivalente a 25% da safra nacional. O fruto da aceroleira e conhecido por apresentar varias propriedades concomitante com o local onde e cultivada. Os frutos foram analisados no Laboratorio de Armazenamento de Produtos Agricolas (LAPA) da UNIVASF – Campus de Engenharias Juazeiro – BA. O experimento foi conduzido em delineamento casualizado com cinco repeticoes e as medias comparadas pelo teste de Tukey a 5%. O objetivo do presente trabalho foi avaliar a vitamina C, peso, diâmetros, Brix°, cor e firmeza de tres variedades produzidas no Vale do Sao Francisco, sendo elas: Flor Branca, Okinawa e Sertaneja nos tres estadios de maturacao. Quanto a analise dos frutos, observou-se que os valores de peso condizem com os diâmetros dos frutos, no estadio de maturacao verde houve maior teor de vitamina C e brix°. Os valores de gama a* houve diferenca significativa entre os frutos semimaduros e maduros, os valores negativos evidenciaram a cor verde. A resistencia mecânica da polpa se apresentou decrescente com o avanco da maturacao.

Avaliação da debulha mecânica em sementes de milho

In the State of Paraiba, the loss of seeds and grains of corn (Zea mays L.) caused, mainly by harvesting, mechanical thrashing and subsequent processes is about 20% resulting in economic loss to the state. In this context, the effect of mechanical damages during the thrashing and passage of corn seeds varieties -Cruzeta- and -Sertanejo- were studied, in the different stages of processing. To evaluate the damages caused to the seeds, a stationary thrasher was used working at 520, 600 and 700 rpm, obtained by the acceleration variation of the tractor to which the thrasher was attached. The damages were visually appraised and analysed in a completely randomized statistical design with the treatments distributed in a factorial scheme. -Cruzeta- variety was more resistant to the impacts caused by the thrashing and processing; the impacts on the seed quality became more evident with the elevation of speed of the thrashing cylinder; the 600 rpm rotation proved to be better for the thashing of Cruzeta and Sertanejo corn.

Determination of mango ripening degree by electrical impedance spectroscopy

Abstract The kinetics of ripening of fruits, followed by subsequent degradation process represent important biochemical mechanisms with high aggregate value for agribusiness sector. In contrast to the destructive assays for identification of ripening degree of fruits, the development of non-invasive techniques introduces potential advantages concerning to the development of new methods for fruit production control. In this direction, the electrical impedance spectroscopy was used for the identification of the maturation degree of fruits based on variation of bulk resistance dependence with maturation of fruits, due to the variation in the liquid content in fruit fibers. The results revealed the strong correlation between mechanical assays and electrical parameters, characterizing an important advantage in terms of a non-invasive and non-destructive method for ripening identification degree.

Produção e estabilidade de conservação de farinha de acerola desidratada em diferentes temperaturas

O objetivo deste trabalho foi identificar a melhor temperatura de desidratacao para a producao de farinha de acerola de alta qualidade de consumo e estabilidade de parâmetros fisico-quimicos durante a conservacao. Frutos de acerola, Flor Branca, foram colhidos no estadio de maturacao maduro em um pomar comercial do Vale do Sao Francisco, Petrolina, PE. Frutos com ou sem sementes foram sanitizados e desidratados nas temperaturas de 60 °C, 70 °C e 80 °C em estufa de circulacao de ar forcado e, em seguida, foram triturados para a obtencao da farinha, a qual foi armazenada em temperatura ambiente em embalagens de polietileno hermeticas. A polpa dos frutos foi utilizada para a determinacao do pH, solidos soluveis (SS), acidez titulavel (AT), acido ascorbico (AA) e umidade. A farinha de acerola foi avaliada a cada 15 dias, por um periodo de 75 dias, quanto ao pH, SS, AT, AA e cor. Para todas as temperaturas de desidratacao, os valores de pH e SS foram semelhantes, variando entre 3,5-4,2 e 6,3-11,7, respectivamente. Os SS apresentaram menor variacao ao final do armazenamento. A AT aumentou em todas as amostras variando de 5% a 10%. As perdas de acido ascorbico foram de 76,2% e 80%, 23,9% e 55%, ou 37,9% e 65% para as farinhas com e sem sementes desidratadas a 60 °C, 70 °C e 80 °C, respectivamente. De acordo com os resultados obtidos, a melhor temperatura de desidratacao e 70 °C, pois resultou em farinha com alta qualidade de consumo e estabilidade de parâmetros fisico-quimicos durante 75 dias de conservacao.

SIMULAÇÃO COMPUTACIONAL DO RESFRIAMENTO DA MANGA TOMMY ATKINS

Este trabalho tem como objetivo simular o resfriamento da manga Tommy Atkins atraves do software ANSYS Mechanical, evidenciando a capacidade dos processos de simulacao computacional aplicada na agricultura como uma opcao na predicao do comportamento termofisico de produtos agricolas. O metodo, de pequeno custo computacional, mostrou-se apropriado para a caracterizacao do processo de resfriamento, tendo como beneficio a aplicabilidade para outros produtos agricolas.

Physiological Seed Quality of Melon as Affected by Fruit Ripeness

ABSTRACT In order to obtain melon (Cucumis melo L.) seed of high physiological quality, the ideal harvesting time needs to be considered, which could be determined by fruit ripening stage. Seed viability of melon, cv. ‘Rock Cantaloup’, was evaluated based on ripening stage. A completely randomized experiment with fruit harvested at ripening stages based on color appearance and presence, or not, of epidermal reticulation, were classified as follows: I, green fruit with nonreticulated epidermis; II, green fruit with reticulated epidermis; III, yellow fruit and reticulated epidermis, and IV, 10 days after yellow fruit and reticulated epidermis. Seed were taken from fruit and evaluated based on moisture percentage, weight of 1000 seed, percentage germination and number of seed that germinated first, seedling formation, seedling growth rate, seedling length, fresh weight, dry weight, and aging speed. Physiological quality of melon seed increased as ripening advanced. Seed obtained from yellow fruit with reticulated epidermis at stage IV were best in all criteria. The best melon seed for germination and quality standards are from well-ripened fruit. However, seed from less mature fruit are still viable for use in melon cultivation.