Efectos de la sal sobre la solubilidad y las propiedades emulsionantes de la caseína y sus hidrolizados trípticos

This work reports an investigation about the effect of NaCl addition (0.02 mol/L) on some functional properties of casein(CA) and its tryptic hydrolysates (TH). The solubility, the emulsifying capacity (EC), the emulsifying activity index(EAI) and the emulsion stability (ES) were determined at two pH values (4.0 and 5.0). The results showed that thisprocedure was benefi cial for the solubility of CA and TH, being more intense at pH 5.0 and 4.0, respectively. Also, apositive effect of NaCl addition was observed for CA and TH, at both pH values, and the best results for both sampleswere achieved at pH 5.0. The ES was slightly affected by the presence of salt and only for some samples of CA andTH it was increased. Contrarily, the EAI values of casein were reduced with the addition of NaCl at pH 4.0 and 5.0,while those of TH were positively affected by this treatment at both pH values.En este trabajo se presentan los resultados de una investigación sobre los efectos de la adición de NaCl (0,02 mol/L)sobre algunas propiedades funcionales de la caseína (CA) y de sus hidrolizados trípticos (TH). Se determinaron lasolubilidad, la capacidad emulsionante (CE), el índice de actividad emulsionante (IAE) y la estabilidad de la emulsión(EE) con dos valores de pH (4,0 y 5,0). Los resultados demostraron que el procedimiento era benefi cioso parala solubilidad de CA y TH, siendo más intensa con pH 5,0 y 4,0, respectivamente. También se observó un efectopositivo de la adición de NaCl en CA y TH, con ambos valores de pH, consiguiéndose los mejores resultados conpH 5,0. La EE se vio ligeramente afectada por la presencia de sal, y sólo aumentó en algunas muestras de CA yTH. Por el contrario, los valores del IAE de la caseína se redujeron al añadir NaCl con pH 4,0 y 5,0, mientras quelas de TH se vieron afectadas positivamente por este tratamiento con ambos valores de pH

Utilización de dos soportes para la inmovilización de la papaína

Papain was immobilized on activated carbon (AC) and on alumina (AL), with the aim of preparing low cost dietarysupplements, using whey as hydrolysed protein source. The quantifi cation of the non-adsorbed enzyme, using Lowry’smethod was used to determine the immobilization rate. The effect of the contact time and the temperature was tested,and 30 min at 250C was considered the best condition for immobilizing papain in both supports. AC showed muchhigher immobilization rates (from 95% to 99%) than AL (from 4% to 13%). The reusability of papain was evaluated bymeasuring the residual activity of the enzyme after it has been used for up to 20 times. The quantifi cation of exposurerate of phenylalanine by second derivative spectrophotometry was used to determine the enzyme activity. In this case, ALshowed better results than AC, since the activity of papain remained unchanged after 15 and 5 times, respectively.Con la intención de preparar suplementos dietéticos de bajo coste, se inmovilizó papaína en carbón activado (CA) yen alúmina, utilizando suero como fuente de proteínas hidrolizadas. Para determinar el índice de inmovilización secuantifi caron las enzimas no adsorbidas mediante el método de Lowry. Se analizó el efecto del tiempo de contactoy la temperatura, considerándose 30 min. a 25 ºC como la condición óptima para inmovilizar la papaína en ambossoportes. El CA presentó unos índices de inmovilización muy superiores (entre 95% y 99%) a los de la AL (entre4% y 13%). Para evaluar la capacidad de reutilización de la papaína se midió la actividad residual de la enzimadespués de haber sido utilizada hasta 20 veces. Para determinar la actividad de la enzima se cuantifi có el índice deexposición de la fenilalanina mediante espectrofotometría de derivada segunda. En este caso, la AL presentó mejoresresultados que el CA, ya que la actividad de la papaína seguía siendo la misma después de haber sido utilizada 15y 5 veces, respectivamente

Green Production of Anionic Surfactant Obtained from Pea Protein

A pea protein isolate was hydrolyzed by a double enzyme treatment method in order to obtain short peptide sequences used as raw materials to produce lipopeptides-based surfactants. Pea protein hydrolysates were prepared using the combination of Alcalase and Flavourzyme. The influence of the process variables was studied to optimize the proteolytic degradation to high degrees of hydrolysis. The average peptide chain lengths were obtained at 3–5 amino acid units after a hydrolysis of 30 min with the mixture of enzymes. Then, N-acylation in water, in presence of acid chloride (C12 and C16), carried out with a conversion rate of amine functions of 90%, allowed to obtain anionic surfactant mixtures (lipopeptides and sodium fatty acids). These two steps were performed in water, in continuous and did not generate any waste. This process was therefore in line with green chemistry principles. The surface activities (CMC, foaming and emulsifying properties) of these mixtures were also studied. These formulations obtained from natural renewable resources and the reactions done under environmental respect, could replace petrochemical based surfactants for some applications