This paper aim to evaluate the ultrafiltration (UF) process for constituents recovery from whey. Sequences of factorial designs were performed by varying temperature (5 to 40°C) and pressure (1 to 3 bar), to maximize the proteins concentration using membrane of 100kDa in dead end system. Based on the best result new experiments were performed with membrane of 50kDa and 10kDa. With the membrane of 50 the protein retention was about 3 times higher than the membrane of 100kDa. The concentrated obtained by UF membrane of 10kDa, 10°C and 2 bar in laboratory scale showed a mean protein retention of 80 %, greater protein solubility, emulsion stability and the identification of β-lactoglobulins (18.3 kDa) and α-lactalbumin fractions (14.2kDa). Therefore, the use of membrane of 100 and 50kDa are became a industrially recommendable alternatives to concentration of whey proteins, and/or as a previous step to the fractionation of whey constituents using membrane ≤10kDa, aiming at future applications in different areas (food, pharmaceutical, chemical, etc.).

RESUMO O objetivo deste trabalho foi obter e caracterizar (físico-química, reológica e microbiologicamente) iogurtes elaborados a partir de leite de ovelha (integral e semidesnatado) e de leite de vaca (integral e semidesnatado). Foram realizadas análises físico-químicas (pH, acidez, proteínas, lactose, gordura, cinzas e minerais) e microbiológicas (Salmonella spp., Staphylococcus coagulase positivas e coliformes a 35 °C), nos leites e nos iogurtes e, de sinérese, nos iogurtes, nos 1°, 15° e 35° dias de armazenamento. A partir das análises físico-químicas, verificou-se que o leite de ovelha, integral e semidesnatado, é mais rico, nutricionalmente, que o leite de vaca integral e semidesnatado, e que os iogurtes com leite de ovelha, tanto integral como semidesnatado, apresentaram os maiores valores de gordura, proteína, pH, lactose, minerais e maior sinérese que os iogurtes com leite de vaca, integral e semidesnatado.

O objetivo do presente trabalho consistiu na extração do óleo da polpa do abacate de variedade Hass utilizando como solvente o etanol e o metanol. Os experimentos foram conduzidos a pressão atmosférica e no intervalo de temperatura entre 283,15 K e 313,15 K. As extrações foram realizadas por um período de 10 horas com amostragens a diferentes tempos de extração. Para ambos os solventes a capacidade de extração apresentou resultados crescentes com o aumento da temperatura. O solvente etanol mostrou maior capacidade de solubilização do óleo da polpa do abacate. Os resultados experimentais foram correlacionados a um modelo que considera que o processo de extração ocorre por dois fenômenos; primeiro o óleo que está na superfície do sólido é rapidamente solubilizado pelo solvente e segundo o óleo residual é removido do interior do sólido por processo difusional.

The interest in collagen use in the food industry to replace synthetic agents is growing every day. Among the derivatives, has the hydrolysate, which dissolves easily in water and brine, and can be incorporated into foods or drinks. The objective of this study was to determine the degree of hydrolysis (DH) of crude collagen fiber, powdered collagen fiber, gelatin and two samples of hydrolyzed collagen. The substrates were subjected to individual action of three proteolytic enzymes: papain, bromelain and collagenase (microbial origin). The substrates were incubated in sodium phosphate buffer (0.1 M, pH 7.0) on an orbital shaker at 55 °C for different periods of time. In 120 minutes of hydrolysis, the crude collagen fiber showed 37.2% of DH using collagenase, the highest value compared to other substrates. The lowest values for DH were obtained for the hydrolysates collagen, with less than 1 % of DH. For hydrolysis in 60 minutes, the DH values were similar to those obtained in 120 minutes of hydrolysis, with minor variations over time. The hydrolytic ability of the collagenase and bromelain was similar and superior compared with the papain.