Application of a Box-Behnken design for optimizing the extraction process of agave fructans (Agave tequilana Weber var. Azul).

BACKGROUND: Agave (Agave tequilana Weber var. Azul) is an industrially important crop in México since it is the only raw material appropriate to produce tequila, an alcoholic beverage. Nowadays, however, these plants have also a nutritional interest as a source of functional food ingredients, owing to the prebiotic potential of agave fructans. In this study, a Box-Behnken design was employed to determine the influence of temperature, liquid:solid ratio and time in a maceration process for agave fructan extraction and optimization. RESULTS: The developed regression model indicates that the selected study variables were statistical determinants for the extraction yield, and the optimal conditions for maximum extraction were a temperature of 60 °C, a liquid:solid ratio of 10:1 (v/w) and a time of 26.7 min, corresponding to a predicted extraction yield of 37.84%. Through selective separation via precipitation with ethanol, fructans with a degree of polymerization of 29.1 were obtained. CONCLUSION: Box-Behnken designs are useful statistical methods for optimizing the extraction process of agave fructans. A mixture of carbohydrates was obtained from agave powder. This optimized method can be used to obtain fructans for use as prebiotics or as raw material for obtaining functional oligosaccharides. © 2015 Society of Chemical Industry.

Effect of free and microencapsulated Lactococcus lactis on composition and rheological properties of Manchego-type cheeses during ripening.

This study aimed at determining the composition and rheology changes during the ripening (60days) of Manchego-type cheeses prepared with Lactococcus lactis subsp. lactis and Lactococcus lactis subsp. cremoris in the free status and microencapsulated in gellan gum. The composition indicated that microencapsulation had a greater influence than the period of ripening since discrepancies were statistically significant (p<0.05) regarding the levels of protein, moisture, total solids and pH between the two cheeses both at the beginning and end of the ripening. Both cheeses presented predominantly elastic characteristics (G'>G″). The moduli and the viscosity significantly increased with the presence of microcapsules and, ripening time. Conversely, the recovery percentages on the creep curve decreased in both cheeses with an increase in ripening as a result of the degradation of proteins. The retarded time ranged between 2.32×10-2 and 2.38×10-2s and the Jo values were 29 times higher than the Ji values in the studied cheeses, indicating the loss of elasticity of the cheeses as they ripen.