Solids rheology for dehydrated food and biological materials

Mechanical properties of food products and biological materials are greatly affected by the drying process and are considered one of the most important quality attributes of dehydrated products. The aim of this work was to review theoretical principles and mathematical modeling, analyzing the measurement techniques and major experimental results that exist in the literature about rheological properties of dehydrated foods and biological materials. Different methods of measuring rheological parameters (fundamental and empiric or imitative) are discussed and major experimental results, as well as the rheological models used in their analysis, published in recent years are presented.

Efeito das condições de congelamento sobre atributos de qualidade de fatias de abacaxi liofilizado

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeito da velocidade de congelamento sobre a liofilização, reidratação e atributos de qualidade de fatias de maçã

Pós-graduação em Engenharia e Ciência de Alimentos - IBILCE

Avaliação do grau de importância dos atributos da qualidade de software definidos pela norma ISO 9126 sob a ótica do produtor rural

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Caracterização morfológica e atributos de qualidade dos frutos de acessos de bananeira em clima subtropical

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

Influência de encapsulantes e do método de secagem nas propriedades físico-químicas e atributos de qualidade de polpa de maracujá (Passifora edulis f. flavicarpa)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Efeitos do tratamento térmico em separado da polpa e do suco sobre a qualidade físico-química, microbiológica, enzimática e sensorial do suco de laranja mantido sob refrigeração

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Atributos produtivos e qualitativos de grãos e fisiológicos e sanitários das sementes de cultivares de feijão

Pós-graduação em Agronomia (Produção Vegetal) - FCAV

Caracterização de surimi obtido a partir da carne mecanicamente separada de tilápia do Nilo e elaboração de fishburger

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Adubação nitrogenada e potássica em goiabeiras ‘paluma’: I. efeito na produtividade e na qualidade dos frutos para industrialização

The nutrition of the orchards is the major factor of productivity, being necessary to know the proper doses of fertilizers and their influence on fruit quality attributes for industrialization. This study evaluated the effects of different doses of nitrogen and potassium on the productivity of guava trees and also on the values of pH, soluble solids (SS), titratable acidity (TA) and pulp/kernel ratio of guavas. The experiment was conducted at Vista Alegre do Alto, SP in an irrigated 'Paluma'guava orchard, 7 years old, managed with pruning during three consecutive cycles of production. The soil of the area was dystrophic Ultisol. The experimental design was the randomized blocks, in factorial, with four nitrogen doses (0, 0.5, 1 and 2 kg of N plant(-1)) and four of potassium (0, 0.55, 1.1 and 2.2 kg of K2O plant(-1)), with three replications. Nitrogen fertilization increased productivity and the pH of the fruit, being explained by the quadratic polynomial regression models; reduced linearly the pulp/kernel ratio and do not influenced the SS and TA values. On the other hand, potassium fertilization and N x K interaction had no significant effects on productivity and the other characteristics evaluated.

Determinação de sólidos solúveis e firmeza em frutos íntegros de pessegueiro por meio da espectroscopia do infravermelho próximo (NIR)

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Chicken meat consumer profile in northwestern São Paulo State, Brazil

Brazil is the world’s first chicken meat exporter nowadays. The maintenance of this position requires a constant quality attributes evolution. This work evaluated the chicken meat consumer profile in the northwest region of São Paulo state, the most important Brazilian poultry meat consumer market, in order to provide information to the productive sector. The data were collected using 482 interviews and questionnaires that were answered by e-mail. The questionnaires involved questions related to the consumer identification, habits and preferences and their knowledge about food safety, production system, sustainability and animal welfare. Most of the consumers, 62%, were female, with ages ranging from 20 to 50 years. Beef was preferred by the majority of the answerers and chicken and pork meat were together the second choice. Only 2% of the interviewed consumers mentioned not enjoying poultry meat. The main part of consumers, 67%, prefer to buy breast and leg cuts and only 11% are used to buy the whole poultry carcass. More than 60% of the interviewed have already eaten free range chicken meat, but the majority of them, 89%, are used to consume regular industrialized poultry. About 75% of the consumers believe hormones are used to grow the birds. Over 80% of people observe the expiration date before buying the product, but only 55% check if it has the stamp of the official inspection service. Color and appearance of meat are the most important factors that influence the consumer’s choice. The amount of water that drips on the tray is a rejection factor to 88% of answerers. Most of them, 66%, prefer lighter colored meat. Only 27% of them believe that chicken meat causes an environmental impact and 48% do not know the meaning of animal welfare. More than half of the interviewed do not consider animal welfare aspects before consuming any kind of meat. From these results obtained, it is possible to conclude that any effort to improve the product quality, mainly concerned to animal welfare and sustainability aspects, requires prior educational initiatives.

Restructured products from tilapia industry by products: the effects of tapioca starch and washing cycles

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Effect of quarantine treatments on the carbohydrate and organic acid content of mangoes (cv. Tommy Atkins)

Brazil is one of the largest mango producers and the third largest mango exporter worldwide. Irradiation treatment and its commercial feasibility have been studied in our country to make it possible to develop new markets and, consequently, to compete with the major exporters of mangoes, Mexico and India. This work was designed to compare irradiation treatment with the hot water dip treatment in mangoes cv. Tommy Atkins for export and to verify that the main attributes for acceptance, color and texture, as well as carbohydrate and organic acid contents, were maintained. In this study, the fruit was divided into groups: control, hot water dip-treated (46 degrees C for 90 min), and irradiation-treated at doses of 0.4 kGy and 1.0 kGy. The fruit was stored at low temperature (11 degrees C +/- 2) for 14 days and then at room temperature (23 degrees C +/- 2) until the end of the study. The results indicated that the fruit given a dose of 1.0 kGy remained in a less advanced stage of ripening (stage 3) throughout the storage period, but experienced a greater loss of texture in the beginning of the experiment. It was noted that only the control group had higher levels of citric acid and succinic acid on the last day of the experiment. There were no significant differences in the total sugar content between any treatment groups. Gamma radiation can be used as a quarantine treatment and does not interfere negatively with the quality attributes of mangoes. (C) 2012 Elsevier Ltd. All rights reserved.

Empirical and fundamental mechanical tests in the evaluation of dough and bread rheological properties

Bread dough and particularly wheat dough, due to its viscoelastic behaviour, is probably the most dynamic and complicated rheological system and its characteristics are very important since they highly affect final products’ textural and sensorial properties. The study of dough rheology has been a very challenging task for many researchers since it can provide numerous information about dough formulation, structure and processing. This explains why dough rheology has been a matter of investigation for several decades. In this research rheological assessment of doughs and breads was performed by using empirical and fundamental methods at both small and large deformation, in order to characterize different types of doughs and final products such as bread. In order to study the structural aspects of food products, image analysis techniques was used for the integration of the information coming from empirical and fundamental rheological measurements. Evaluation of dough properties was carried out by texture profile analysis (TPA), dough stickiness (Chen and Hoseney cell) and uniaxial extensibility determination (Kieffer test) by using a Texture Analyser; small deformation rheological measurements, were performed on a controlled stress–strain rheometer; moreover the structure of different doughs was observed by using the image analysis; while bread characteristics were studied by using texture profile analysis (TPA) and image analysis. The objective of this research was to understand if the different rheological measurements were able to characterize and differentiate the different samples analysed. This in order to investigate the effect of different formulation and processing conditions on dough and final product from a structural point of view. For this aim the following different materials were performed and analysed: - frozen dough realized without yeast; - frozen dough and bread made with frozen dough; - doughs obtained by using different fermentation method; - doughs made by Kamut® flour; - dough and bread realized with the addition of ginger powder; - final products coming from different bakeries. The influence of sub-zero storage time on non-fermented and fermented dough viscoelastic performance and on final product (bread) was evaluated by using small deformation and large deformation methods. In general, the longer the sub-zero storage time the lower the positive viscoelastic attributes. The effect of fermentation time and of different type of fermentation (straight-dough method; sponge-and-dough procedure and poolish method) on rheological properties of doughs were investigated using empirical and fundamental analysis and image analysis was used to integrate this information throughout the evaluation of the dough’s structure. The results of fundamental rheological test showed that the incorporation of sourdough (poolish method) provoked changes that were different from those seen in the others type of fermentation. The affirmative action of some ingredients (extra-virgin olive oil and a liposomic lecithin emulsifier) to improve rheological characteristics of Kamut® dough has been confirmed also when subjected to low temperatures (24 hours and 48 hours at 4°C). Small deformation oscillatory measurements and large deformation mechanical tests performed provided useful information on the rheological properties of samples realized by using different amounts of ginger powder, showing that the sample with the highest amount of ginger powder (6%) had worse rheological characteristics compared to the other samples. Moisture content, specific volume, texture and crumb grain characteristics are the major quality attributes of bread products. The different sample analyzed, “Coppia Ferrarese”, “Pane Comune Romagnolo” and “Filone Terra di San Marino”, showed a decrease of crumb moisture and an increase in hardness over the storage time. Parameters such as cohesiveness and springiness, evaluated by TPA that are indicator of quality of fresh bread, decreased during the storage. By using empirical rheological tests we found several differences among the samples, due to the different ingredients used in formulation and the different process adopted to prepare the sample, but since these products are handmade, the differences could be account as a surplus value. In conclusion small deformation (in fundamental units) and large deformation methods showed a significant role in monitoring the influence of different ingredients used in formulation, different processing and storage conditions on dough viscoelastic performance and on final product. Finally the knowledge of formulation, processing and storage conditions together with the evaluation of structural and rheological characteristics is fundamental for the study of complex matrices like bakery products, where numerous variable can influence their final quality (e.g. raw material, bread-making procedure, time and temperature of the fermentation and baking).