Fermentative capability and aroma compound production by yeast strains isolated from Agave tequilana Weber juice

Five yeast strains isolated from agave juice were studied for their fermentative and aromatic capacity. The experiments were performed using agave juice supplemented with ammonium sulphate, as is commonly done in tequila distilleries. Three strains classified as Saccharomyces cerevisiae showed high biomass and ethanol production, as well as higher ethanol tolerance than those classified as Kloeckera africana and Kloeckera apiculata, which showed scarce growth. The results suggest that Kloeckera strains were affected by nutritional limitation and/or toxic compounds present in agave juice. Agave juice analyses showed a lower amino acid content than those reported in grape juice. S. cerevisiae strains produced predominantly amyl and isoamyl alcohols, n-propanol, 2-phenyl ethanol, succinic acid, glycerol, methanol, isoamyl acetate, ethyl hexanoate, acetaldehyde and isobutanol, whereas Kloeckera strains showed a high production of acetic acid, 2-phenyl ethyl acetate and ethyl acetate. The methanol concentration was significantly different among the yeasts studied. The diversity between three S. cerevisiae strains were higher for the aromatic profile than for genetic level and kinetic parameter. On the other hand, the diversity of Kloeckera yeasts were lower than Saccharomyces yeasts even when belonging to two different species

Effect of Supercritical Fluid Extraction Process on Chemical Composition of <i>Polianthes tuberosa</i> Flower Extracts

Supercritical fluid extracts from flowers of Polianthes tuberosa var. double were ob tained using carbon dioxide as a solvent. Yield extract obtained was 2.5%. The effects of the pressure process (18 MPa, 28 MPa, and 38 MPa) and temperature process (313 K, 323 K, and 333 K) on the volatile composition of tuberose flowers extracts were evaluated, and a significant variation in chemical composition was found. Characteristic compounds of tuberose as methyl isoeugenol, benzyl benzoate, methyl anthranilate, pentacosene, and heptacosene were obtained mainly at 18 MPa and 333 K process conditions, and could be used in the perfume or fragrance industry. Components such as geraniol, farnesol, and methyl eugenol were also obtained, these extracts could be used in the development of cosmeceutical products. This work allowed to identification of the chemical composition profile and evaluation of the changes in tuberose extracts due to the extraction process