Formation of Higher Alcohols During Grape Juice Fermentations at Various Temperatures

Abstract

SUMMARY Significant effects of fermentation temperature on the formation of fusel oils in grape juice media were demonstrated. Isoamyl alcohol was formed most abundantly at 70–80°F, and n‐propyl alcohol least abundantly. Isobutyl alcohol formation seems fairly independent of fermentation temperature. The formation of active amyl alcohol was affected but slightly, in a manner similar to isoamyl. The levels of the sum of the two amyl alcohols formed were 6–131% (averaging 47%) higher with fermentation at 70 or 80°F than with fermentation at 50°F. This effect is considered significant for commercial practice. Possible interpretations of the results are discussed along with pathways of higher alcohol formation.

Estudio de la actividad fermentativa de Hansenula anomala y producción de compuestos químicos de importancia sensorial

“…El oxígeno promueve el metabolismo respiratorio y como consecuencia un mayor flujo de glucosa y aminoácidos, cuya degradación produce compuestos intermediarios (cetoácidos) de la síntesis de alcoholes superiores (Ribereau-Gayon et al 1975;Valero et al 2002). Otros factores que incrementan la producción de alcoholes superiores incluyen la clarificación del mosto, la madurez de la fruta, la temperatura entre otros (Ough et al 1966;Blanco et al 1992;Mangas et al 1994). …”

Review: Steam distilled spirits from fermented grape pomace Revision: Bebidas destiladas obtenidas de la fermentación del orujo de uva

“…Several factors can affect formation of higher chain alcohols: (i) intensity of maceration of grapes during winemaking, because it affects the degree of degradation of pectins by adventitious pectinases (Orriols, 1992(Orriols, , 1994); (ii) concentration of fermentable substrates, because the source of nitrogen used by yeasts influences that formation (Bidan,1975); (iii) type of yeasts present during alcoholic fennentation, because they may be differently affected by aeration (Rankine, 1967); and (iv) temperature and pH prevailing during fermentation (Ough et al, 1966), because they affect the numbers and kinds of yeasts, as mentioned before.…”

“…Most esters are exclusively produced via microbial endocellular reactions, which are naturally affected by temperature, microbial strain, medium composition (especially profile of nitrogen-containing nutrients) and presence (or absence) of sulfur dioxide (Ough et al, 1966; Daugh and Ough, 1973;Soles et al, 1982); formation of certain esters (especially those possessing longer chain acid moieties) actually correlates with yeast growth (Onishi ct al., 1978). Ethyl caprylate, ethyl caprate and ethyl laurate are recovered in the distillate to significantly greater extents if yeasts cells were present in the grape pomace, whereas the concentrations of isoamyl acetate, ethyl caproate and 2-phenyl-acetate do not depend appreciably upon the viable numbers of yeasts.…”

Effects of transport conditions on the stability and sensory quality of wines

“…This change can occur by oxidation or reduction, and the concentration of some volatile compounds can increase or decrease, such as methyl butanol, a compound associated with off-odours when present at a high concentration in a wine (De Lerma et al, 2012;Fariña et al, 2015). For example, the presence of amyl alcohols reinforces the in-mouth structure of the alcoholic beverage, but at temperatures above 26 °C they increase in concentration (Ough et al, 1966); an excess of these compounds (> 400 mg/L) is associated with a poor quality product and unpleasant odors (Rapp and Versini, 1995).…”