Construction of Chemoenzymatic Linear Cascades for the Synthesis of Chiral Compounds

Inspired by nature, synthetic chemists try to mimic the efficient metabolic networks in living organisms to build complex molecules by combining different types of catalysts in the same reaction vessel. These multistep cascade processes provide many advantages to synthetic procedures, resulting in higher productivities with lower waste generation and cost. However, combining different chemo- and biocatalysts can be challenging as reaction conditions might differ greatly. As a highly multidisciplinary field that benefits from advances in chemical catalysis, molecular biology and reaction engineering, this area of study is rapidly progressing. In this Review, we highlight recent trends and advances in the construction of multistep chemoenzymatic one-pot cascades to access chiral compounds as well as the different strategies to solve current challenges in the field

Distribution of the principal minor volatiles during cider destillation in "alquitara"

A study of minor volatiles from 12 fractions collected during distillation of cider in ‘alquitara’ was carried out. Compounds favouring spirit quality are found in the first half of the distillate. Some compounds imparting aromatic defects could be eliminated by removing a percentage of heads during distillation. In contrast, when distilling ciders without defects, removing heads would not be justified, as their incorporation in the final distillate should lead to obtaining spirits with higher aromatic riches. Tails, however, which are mainly constituted by unpleasant aromas, must be rigorously removed to avoid incorporating compounds that could reduce the quality of the final product

Influence of Distillation System, Oak Wood Type, and Aging Time on Composition of Cider Brandy in Phenolic and Furanic Compounds

A control of phenolic and furanic compounds in cider brandy was carried out during maturation in oak casks, studying three technological factors: distillation (rectification column vs double distillation), oak wood type (French vs American), and aging time (32 months). Gallic acid and benzoic and cinnamic aldehydes significantly increased during maturation of cider brandies, the highest level of these phenolics being obtained when aging was conducted in French oak casks. Benzoic acids increased during aging, though furanic compounds were not influenced by the time factor. Distillation and wood factors significantly influenced furanic concentration; 5-hydroxymethylfurfural not was detected in fresh spirits and was extracted in the highest proportion in French oak. Volatile furanics, such as 5-methylfurfural, furfural, and 2-furylmethyl ketone, were influenced by the distillation factor, with the use of the double distillation system producing a higher level of these compounds. Scopoletin was the majority coumarin detected in cider brandies, the highest yield of which was obtained with the use of American oak

Solid-phase extraction and high-performance liquid chromatographic determination of polyphenols in apple musts and ciders

An improved analytical method was developed for the determination of polyphenols in the apple products must and cider. Phenolic compounds were fractionated into neutral and acidic groups by means of a solid-phase extraction method. The analytical method proposed was effective for the quantitation of phenolic compounds; recoveries between 84% and 111% were obtained, and the relative standard deviation was usually less than 5%