Guillermo A. Sihufe

Natural astaxanthin encapsulation: Use of response surface methodology for the design of alginate beads

Nowadays, consumers are more conscious about healthier products consumption benefits. Astaxanthin obtained from the microalgae Haematococcus pluvialis represents a natural ingredient for the nutraceutical and functional food industries. It is claimed that astaxanthin has much stronger antioxidant activity than vitamin E and β-carotene, providing different health benefits. However, the unstable structure of the molecule limits its application in functional foods development. Therefore, the present study evaluates the effect of five independent formulation and process variables for natural astaxanthin oleoresin encapsulation using an external ionic gelation technique. Response surface methodology can be used for studying the effect of several factors at different levels and their influences on each other, which overcomes the shortcoming of the traditional orthogonal method. The results showed that alginate and CaCl2 concentrations have a significant effect on particles size obtained, while alginate/oleoresin ratio and surfactant concentration greatly influence the astaxanthin oleoresin release rate. In vitro studies under simulated intestinal conditions showed that astaxanthin oleoresin release process can be described by Hopfenberg model. Three mathematical models were obtained for predicting particle size, astaxanthin release rate and encapsulation yield under different process conditions, providing a platform for microencapsulation technology optimization for healthy food design.

Enhancement of astaxanthin production from Haematococcus pluvialis under autotrophic growth conditions by a sequential stress strategy

Abstract The study of microalgal culture has been growing in recent decades, because the cellular structure of microalgae has diverse highly valuable metabolites that have attract attention of numerous companies and research groups. The pigment astaxanthin is considered one of the most powerful antioxidants in nature. The microalga Haematococcus pluvialis was proposed as one of the best natural astaxanthin sources, because it can accumulate high amount of the pigment. In this work, we studied different stress treatments on H. pluvialis growth cultures as well as astaxanthin production under autotrophic growth conditions. The results showed that extending nitrogen starvation before increasing radiation intensity up to 110 μmol photons m−2 s−1 during late the palmella cell phase incremented the astaxanthin concentration up to 2.7% of dry biomass with an efficient light energy utilization during the stress stage.

Influence of technological variables on the functionality of the cell-free fraction of fermented buttermilk

Buttermilk is a suitable substrate for fermentation with proteolytic strains of Lactobacillus in order to release peptide fractions able to enhance the gut mucosal immune system. We aimed to determine the influence of the degree of proteolysis of buttermilk proteins on their functionality. Animals received for seven consecutive days the cell-free fraction of 10 or 20% (w/v) buttermilk fermented with Lactobacillus delbrueckii subsp. lactis 210 at pH 6. The pH was controlled either with NaOH or Ca(OH)2. No significant differences in the number of IgA-producing cells in the small intestine of mice were found. The functional capacity of the product under study was not affected by the technological variables considered.