4 research outputs found
MAJOR GOAT MILK PROTEIN: SEPARATION AND CHARACTERIZATION BY “LAB-ON-A-CHIP” MICROFLUIDIC ELECTROPHORES
This work presents the electrophoretic profile of goat and cow milk samples and their mixtures using microfluidic and conventional electrophoresis. The microfluidic method allowed the separation of the major caseins from milk, excepting the goat κ-casein.  Besides, the major whey proteins were separated with perfect distinction of A and B β-lactoglobulin variants. Comparing to SDS-PAGE, a variation in the molecular weight was observed in all milk proteins. However, A and B β-lactoglobulin variants could not be isolated using SDS-PAGE. Although urea-PAGE did not show high resolution among whey proteins, γ-, κ-, β-, and α-caseins were clearly identified. This method also showed a lower limit detection of cow milk in mixture samples than the "lab-on-a-chip" electrophoresis. In both methods, the highest linearity obtained from plotting total percentage against cow milk concentration was observed by using cow αs1-casein (R2 = 0.986 and R² = 0.973). This result indicates that microfluidic electrophoresis is an effective tool to detect the presence of some proteins in goat and cow milk, and in mixtures. Microfluidic chip technology might will complement the current methods for analyzing milk proteins, highlighting its speed amount of reagents and whey protein separation, which showed a better result than urea or SDS-PAG
Estudo comparativo entre as técnicas de eletroforese em gel de poliacrilamida ureia-page e lab-on-a-chip para a detecção de fraude do leite de cabra pela adição de leite bovino
Milk is a food of great relevance in human nutrition. In addition, among the different food industries in Brazil, the dairy industry is one of the economically expressive. Cow's milk was be substituted for goat‟s milk in any situation. The goat‟s milk presents better digestibility and low allergenic potential. However, it is common adulteration of goat milk with cow‟s milk. Some factors like low income of goat milk and the lower price of cow‟s milk contribute for this kind of fraud. The present study aimed to evaluate polyacrylamide gel electrophoresis techniques in presence of urea (UREA-PAGE) and microfluidic lab–on–a–chip, in order to characterize the protein profile of milk in the different species goat and cow. In addition, establish faster and efficient techniques for fraud detection in goat‟s milk. The fraud detection in goat‟s milk by the addition of cow milk was analyzed using the electrophoretic profiles of the proteins by the polyacrylamide gel electrophoresis methods UREA–PAGE and microfluidic lab-on-a-chip electrophoresis. Both studded methods showed the αs1 – casein bovine as a marked for this fraud detection. The UREA–PAGE techniques detected the bovine‟s milk αs1- casein from 2% of cow milk added to caprine milk. However lab-on–a-chip technique detected bovine‟s milk αs1- casein from 20% of addition. The microfluidic electrophoresis in microchip allowed the separation of the milk‟s proteins from the both species tracing their respective electrophoretic profiles with fast results availability; this method has great relevance in milk‟s fraud investigations in routine labs. The use of lab-on-a-chip has resulted in the rapid procedures as the run time is about four hours. Due to the need for automated, fast and efficient techniques to attend the dairy industry and the regulatory agencies request, it‟s necessary the development of the lab-on-a–chip technique in order to improve their performance and applicability.O leite Ă© um alimento de grande relevância na alimentação humana. NĂŁo obstante, dos diferentes setores da indĂşstria alimentĂcia, o setor de laticĂnios destaca-se por estar entre os mais expressivos economicamente no Brasil. O leite de vaca, o mais consumido, pode ser substituĂdo pelo leite de cabra principalmente porque este apresenta maior digestibilidade e baixo potencial alergĂŞnico. No entanto, uma prática fraudulenta consiste na adulteração do leite caprino com leite bovino. Dentre alguns fatores que contribuem para tal, estĂŁo o menor rendimento na produção de leite de cabra, em conjunto com o preço mais baixo do leite de vaca. O presente estudo objetivou avaliar as tĂ©cnicas de eletroforese em gel de poliacrilamida na presença de ureia (UREIA-PAGE) e eletroforese microfluĂdica lab-on-a-chip, a fim de caracterizar o perfil proteico do leite de cabra e vaca e estabelecer tĂ©cnicas rápidas e eficientes para detecção de fraude no leite de cabra. A detecção da fraude no leite de cabra por adição do leite de vaca foi testada pelo perfil eletroforĂ©tico das proteĂnas usando os dois mĂ©todos citados acima. Os dois mĂ©todos avaliados mostraram que a fração αS1 - caseĂna bovina pode ser utilizada como um marcador para detecção desta fraude. Com a tĂ©cnica de UREIA-PAGE foi possĂvel detectar a presença da αS1-caseĂna do leite bovino a partir de 2% de leite bovino adicionado ao leite caprino. Entretanto com a tĂ©cnica lab-on-a-chip sĂł foi possĂvel detectar a partir de 20% de adição. Pelo mĂ©todo de eletroforese microfluĂdica foi possĂvel visualizar o perfil proteico do leite das diferentes espĂ©cies (bovino e caprino) traçando seus respectivos perfis eletroforĂ©tico, com disponibilização rápida dos resultados. O que permite uma investigação de fraude de leite para laboratĂłrios de rotina por meio de um mĂ©todo rápido, já que todo o procedimento dura cerca de 4 horas e permite um grau de automação maior. Devido Ă necessidade de tĂ©cnicas eficientes, rápidas, automatizadas para atender a demanda da indĂşstria de laticĂnios e dos ĂłrgĂŁos de fiscalização, faz-se necessário o aperfeiçoamento da tĂ©cnica lab-on-a-chip com o intuito de melhorar seu desempenho e aplicabilidade, possibilitando a detecção de nĂveis mais baixos de fraude