Abstract The aim of this study was a contribution to standardazation the process of making mozzarella cheese from goat milk by draining at different pH values 5.0 (MC50), 5.3 (MC53) and 5.6 (MC56), so as to obtain a product with suitable physicochemical, microstructural and textural characteristics. MC50 had lower protein and calcium, with very few strands. MC53 had adequate moisture content, fat, protein and calcium. The cheese yield was higher, the hardness parameters were lower, and the microstructure revealed the presence of long, thin strands, giving it the distinctive texture for this type of cheese. MC56 curd did not reach a good stretching property, requiring longer exposure to heating to obtain the yarn. This resulted in lower retention of fat, lower cheese yield, increased calcium and hardness values, and absence of strands. Overall, the goat milk presented aptitude for processing this type of cheese, however the pH 5.3 was selected to obtain a product with suitable physicochemical, textural and microstructural characteristics.

AbstractKiwicha has significant nutritional characteristics. It is commonly used as a puffed product, but there is little research on the lamination process. In this paper, the physical, functional properties, chemical composition and acceptability of the precooked kiwicha grains were studied. Puffed (PK) and laminated kiwicha (LK) were made. Puffed amaranth (CPA) was used as a commercial reference standard. The raw grain (RG) showed a higher bulk density (0.85 g/ml) than in PK (0.18 g/ml) and LK (0.38 g/ml). Both products had a good expansion. The yellow index decreased in PK (50.92) and LK (45.87) respect to RG (65.64). The largest was CPA (58.54). In all the products, the precooking increased the index of absorption, solubility and swelling power. Also, they showed major pasting temperature, low peak viscosity and breakdown viscosity. In both formulated products, the content of total, soluble and insoluble dietary fibre decreased during the precooking process. The content of protein was optimal (between 14.57-14.59 g/100g). PK had high acceptability (5.84), preference (84.48%), purchase (38.79%) and consumption (43.96%) intention. The lowest was CPA. This work demonstrates that it’s feasible to make precooked products with good quality characteristics, chemical composition and acceptability for the development of new products.

As propriedades funcionais de filmes à base de amido de milho foram melhoradas pela incorporação de nanoargila (montmorilonita). Nanoargila foi incorporada na matriz polimérica por meio de duas metodologias diferentes e os filmes foram produzidos por casting. Os efeitos da metodologia de preparação e da concentração de nanoargila nas propriedades físico-químicas dos filmes foram estudados. Conforme os métodos de elaboração, filmes intercalados e esfoliados de nanocompósitos foram obtidos. Os espectros FTIR mostraram uma forte interação entre a argila montmorilonita e as moléculas de amido. A opacidade foi dependente do método utilizado para a dispersão da nanoargila. A solubilidade e a permeabilidade ao vapor de água diminuíram com o aumento do teor de montmorilonita e ambas as propriedades foram afetadas pelo método de dispersão. A difusão de água foi dependente do conteúdo de nanoargila, em razão do aumento na tortuosidade do caminho de difusão causado pelas nanopartículas. Os resultados mostraram que a incorporação de 5% de montmorilonita pelo método de dispersão adequado melhorou a resistência à água e as propriedades de barreira dos filmes de amido de milho. As nanopartículas reduziram os danos causados nas propriedades desses filmes hidrofílicos pelo aumento do teor de umidade.

The functional properties of corn starch based films were improved by incorporating nanoclay (Montmorillonite). Nanoclay was incorporated in the polymer matrix using two different methodologies and the films were formed by casting. The effect of film preparation methodology and of the nanoclay concentration on the physicochemical properties of the films was studied. Depending on film preparation method used, intercalated or exfoliated nanocomposite films were obtained. The FTIR spectra showed a strong interaction between the montmorillonite and the starch molecules. Opacity was dependent on the nanoclay dispersion method used. Water vapor solubility and permeability decreased with increasing montmorillonite content and were affected by the dispersion method. Water diffusion was only dependent on the nanoclay content due to the increase in tortuosity of the diffusion path, caused by the nanoparticles. The results showed that the incorporation of 5% of montmorillonite using an adequate dispersion method, improved the water resistance and barrier properties of corn starch based films. Nanoparticles reduced the damage caused to the properties of these hydrophilic films by the increase in moisture content.

No presente estudo, é apresentado um melhor conhecimento da influência do teor em plastificante, da umidade relativa de armazenamento e da espessura do filme nas propriedades mecânicas do filme baseado em amido de milho de alto conteúdo de amilose, gelatinizado em baixa temperatura. As propriedades mecânicas, a resistência à tração e a porcentagem de alongamento na ruptura dos filmes de amido de milho de alta amilose plastificados com glicerol foram avaliadas utilizando-se testes da tensão. Os filmes apresentaram aumento do alongamento na ruptura e diminuição da resistência à tração com a concentração crescente de plastificante. Quando o nível de glicerol foi elevado, algumas fissuras nos filmes secos foram detectadas, possivelmente em razão dos fenômenos de separação de fases (amido-glicerol). A cristalinidade do filme está relacionada à capacidade de reorganização da cadeia polimérica; assim, a cristalinidade relativa do filme deve aumentar com o conteúdo de plastificantes (glicerol e água). As propriedades mecânicas mostraram-se fortemente dependentes do teor de água, por causa da natureza hidrofílica dos filmes de amido. A influência da umidade de sorção na resistência à tração foi semelhante à plastificação com glicerol. A relação entre a mobilidade da cadeia polimérica e o teor em água explica esse comportamento. O alongamento sofreu um efeito diferente: valores máximos foram atingidos em 45% da umidade relativa. A queda final em alongamento deveu-se ao amolecimento da estrutura em umidade relativa alta. Os filmes mais espessos requerem mais tempo de secagem; dessa forma, a cristalinidade relativa é maior porque se aumenta a possibilidade de reorganização das cadeias. Como consequência, foi observado um aumento linear da resistência à tração e do alongamento na ruptura em relação à espessura do filme, sobre toda a faixa estudada (30 a 100 µm).

In the present study, a better knowledge of the influence of plasticizer content, storage relative humidity and film thickness on the mechanical properties of high amylose corn starch based films gelatinized at low temperature, is presented. The mechanical properties, tensile strength and percentage of elongation at break of high amylose corn starch films plasticized with glycerol were evaluated using tension tests. The films exhibited an increase in elongation and a decrease in tensile strength with increasing plasticizer concentration. When the glycerol level was high, some fissures were detected in the dry films, possible due to phase separation (starch-glycerol) phenomena. Film crystallinity is related to the reorganization capacity of the polymer chain, and thus the relative film crystallinity should increase with plasticizer content (glycerol and water). The mechanical properties were found to be strongly dependent on the water content due to the hydrophilic nature of starch films. The influence of moisture sorption on tensile strength was similar to that of plasticization with glycerol. The relationship between polymer chain mobility and water content explained this behavior. Elongation suffered a different effect and maximum values were reached at 45% relative humidity. The final drop in elongation was due to a softening of the structure at high relative humidity. The thicker the film the longer the drying time required, leading to greater relative crystallinity due to the corresponding increase in the possibility for chain reorganization. As a consequence, linear increases in tensile strength and elongation were observed with film thickness over the whole range studied (30 to 100 µm).

Se formularon alimentos sin gluten para celíacos en base a mezclas de harina de quínoa (Chenopodium quinoa), arroz y maíz con almidones. Para la formulación de estos alimentos se usó la herramienta informática (ALIM V1.0) desarrollada por los autores. Se obtuvieron panqueques, scones, prepizza y pan, los cuales fueron evaluados en composición química (proteínas, grasas, cenizas, fibras, humedad y carbohidratos). También se determinaron actividad de agua (a w), aceptabilidad y parámetros de textura (dureza, gomosidad, masticabilidad, adhesividad, cohesividad). Se tomaron como referencia productos comerciales (C) a los que se les realizaron los mismos análisis que a los productos formulados (F). Se encontraron diferencias significativas en los contenidos de proteínas, grasas, humedad, cenizas, fibras y en la mayoría de los parámetros de textura estudiados en ambos grupos de productos (pw de los productos (F) y (C) resultaron similares a los datos citados en bibliografía para productos análogos. Las formulaciones más aceptables fueron los scones y los panqueques con valores superiores al 80%. Los productos formulados en general aportan proteínas de buena calidad, poseen buenas características texturales y adecuados porcentajes de aceptabilidad para ser usados en la alimentación de pacientes celíacos.

Gluten free food for people with celiac disease based on quinoa, rice and corn flours and starches, were formulated. An informatic tool (ALIM V 1.0) developed by the authors, was used for the formulation of these foods. The obtained products were pancakes, scons, precooked pizza and bread which were analyzed in their chemical composition (protein, fat, fiber, moisture, ash and carbohydrates). Water activity (a w), acceptability and texture parameters (hardness, gumminess, chewiness, adhesiveness and cohesiveness) were also determined. Commercial products (C) were taken as reference and were performed the same analysis to formulated products (F). Significant differences were found in protein, fat moisture, ash and fiber content and in most of the texture parameters studied in both food groups (pw of products (F) and (C), gave values similar to the data cited on bibliography for analogous products. The formulations more acceptable (values over 80%) were scones and pancakes. Overall, the formulated products provide good quality proteins, have good textural characteristics and adequate percentages of acceptability to be used in the feeding of celiac patients.