Fractional mixture design: a novel design and methodology for analyzing and optimizing mixtures of several ingredients.

Mixture designs are employed to systematically change the composition of mixtures and investigate how those changes impact their properties. However, all mixture designs currently available are impractical for analyzing mixtures with relatively large numbers of ingredients. In response, this article presents a novel solution that builds on the construction of a new experimental design called "fractional mixture design". The design involves screening the ingredients in mixtures and enables the subsequent construction of a classical mixture design for optimizing mixtures. The design and its accompanying methodology were developed to analyze native strains found in successful spontaneous fermentations with the goal of constructing a mixed starter culture to transition from spontaneous to directed fermentation in the production of agave distillates. The results showed that a starter culture composed of the native strains Kluyveromyces marxianus, Clavispora lusitaniae, and Kluyveromyces marxianus var. drosophilarum, in respective proportions of 35%, 32%, and 33%, enabled the production of a fermented product with 2.1% alcohol and a broad profile of aromatic compounds. Hence, the results show, for the first time, a tool that addresses the technical challenge that allows studying a relatively large number of ingredients in mixtures and a two-stage sequential methodology to construct optimal mixtures.

One-domain approach for studying multiphase transport phenomena in biofilm growing systems.

The one-domain approach (ODA) was used as an alternative to solve fluid-biofilm interfacial behavior in a 2-D model for diffusion-reaction-convection coupled with prediction of irregular growth of biofilms via a cellular automaton strategy. The simulations exhibited errors of <7% compared with the porosity of a previously reported capillary experimental system. Additionally, biofilm surface geometrical aspects were satisfactorily compared with reports of experimental and similar rigorously simulated benchmark systems. The method developed was applied to simulate typical biofilm systems predicting recirculation flow patterns, interface concentration profiles, and clogging of the inlet section of the capillary tube, which are phenomena that affect the efficiency of diverse biotechnological applications, including membrane bioreactors and biofilters. The ODA method applied to the governing equations of momentum and mass transfer combined with a cellular automaton algorithm is a suitable and straightforward approach for modeling solid-state fermentation at different sophistication levels.

Enzymatic treatment to improve extraction of capsaicinoids and carotenoids from chili (Capsicum annuum) fruits.

Enzymatic treatments using noncommercial enzymes as a means to the improve the extraction of carotenoids and capsaicinoids from chili fruits are explored in this study. The results show that it is possible to obtain chili fruit powder with a higher concentration of both capsaicinoids and carotenoids than previously reported for similar processes. Furthermore, extraction yields above 96% for carotenoids and 85% for capsaicinoids as separate fractions can be achieved using a sequential and selective two-stage extraction. Evidence is presented demonstrating that the content and extraction yield depend directly on the extent of the enzymatic hydrolysis of chili cell walls, and higher yields are obtained when the sample is completely hydrolyzed. The enzymatic treatment described here is a promising alternative to current industrial practices, and it improves the extraction of carotenoids and capsaicinoids from chili fruits.

Improving xanthophyll extraction from marigold flower using cellulolytic enzymes.

In this work is studied the effect of a noncommercial enzyme preparation on xanthophyll extraction from marigold flower (Tagetes erecta). The enzymatic extract was synthesized by endogenous microorganisms previously isolated and identified as Flavobacterium IIb, Acinetobacter anitratus, and Rhizopus nigricans. The results show that the extraction yield depends directly on the extent of the enzymatic hydrolysis of cell walls in the flower petals and that it is possible to reach yields in excess of those previously reported for treatments with commercially available enzymes (29.3 g/kg of dry weight). HPLC analysis of the product indicates that the original xanthophyll profile is not altered. The enhanced extraction system appears to be very competitive when compared to the traditional process and current alternatives.

Mixed culture optimization for marigold flower ensilage via experimental design and response surface methodology.

Endogenous microorganisms isolated from the marigold flower (Tagetes erecta) were studied to understand the events taking place during its ensilage. Studies of the cellulase enzymatic activity and the ensilage process were undertaken. In both studies, the use of approximate second-order models and multiple lineal regression, within the context of an experimental mixture design using the response surface methodology as optimization strategy, determined that the microorganisms Flavobacterium IIb, Acinetobacter anitratus, and Rhizopus nigricans are the most significant in marigold flower ensilage and exhibit high cellulase activity. A mixed culture comprised of 9.8% Flavobacterium IIb, 41% A. anitratus, and 49.2% R. nigricans used during ensilage resulted in an increased yield of total xanthophylls extracted of 24.94 g/kg of dry weight compared with 12.92 for the uninoculated control ensilage.