Effects of Different Inoculation Regimes of Torulaspora delbrueckii and Oenococcus oeni on Fermentation Kinetics and Chemical Constituents of Durian Wine

Abstract

This work evaluated the effects of inoculation time of Oenococcus oeni on the kinetics of fermentation and chemical constituents of durian wine produced using a non-Saccharomyces yeast, Torulaspora delbrueckii. The growth of T. delbrueckii in mixed-culture fermentations was significantly adversely affected by the presence of O. oeni, and the growth of malolactic bacteria was also affected by the metabolism of yeast during fermentation. The level of ethanol produced in simultaneous alcoholic and malolactic fermentation (SIM, 6.93%, v/v) was comparable to that in the Saccharomyces cerevisiae EC-1118 control (6.75%, v/v); both levels were relatively higher than that in the T. delbrueckii Biodiva control (6.39%, v/v) and the other two sequential fermentations (oenococci inoculated after four and seven days of alcoholic fermentation, SEQ 4 th , 6.34% and SEQ 7 th , 6.33% v/v respectively). The final concentrations of organic acids and esters in the mixed-culture wines were correlated with the inoculation time of O. oeni. SIM produced relatively higher levels of ethyl esters (ethyl esters of hexanoate, octanoate, decanoate and lactate) and acetate esters (ethyl acetate and isoamyl acetate) than those in SEQ 4 th , SEQ 7 th and the Biodiva control. This suggests that SIM would contribute fruity aroma properties to and modulate the mouthfeel of durian wine. The production of 3-(ethylthio)-1-propanol could compensate for the weak onion-like odour caused by the decrease in initial volatile sulphur compounds. Overall, this research suggests that SIM treatment is an effective way to produce durian wine with higher ester production.

Transforming Spent Coffee Grounds’ Hydrolysates with Yeast Lachancea thermotolerans and Lactic Acid Bacterium Lactiplantibacillus plantarum to Develop Potential Novel Alcoholic Beverages

“…This indicated that, although yeast died early, the ethanol likely inhibited the LAB, supported by the different ethanol levels and different LAB counts in co- and sequential fermentation. The results agreed with a previous study [ 10 ], where the highest cell population of LAB in mixed inoculation was also similar to that of LAB mono-inoculation. In addition, the decline of LAB may also be due to the lack of nutrients or the accumulation of other substances such as medium-chain fatty acids and certain peptides/proteins [ 9 , 10 ].…”

“…The results agreed with a previous study [ 10 ], where the highest cell population of LAB in mixed inoculation was also similar to that of LAB mono-inoculation. In addition, the decline of LAB may also be due to the lack of nutrients or the accumulation of other substances such as medium-chain fatty acids and certain peptides/proteins [ 9 , 10 ].…”

“…For MLF, Oenococcus oeni is the most widely used LAB species due to its good capability of catabolizing malic acid, growing well in various media, and generating pleasant aroma compounds (e.g., diacetyl, esters, and higher alcohols). However, this kind of LAB can produce undesirable levels of acetic acid from excess sugars if it grows spontaneously or is inoculated early in the yeast fermentation stage when the sugar level is still high [ 10 ].…”

The Quality of Ciders Depends on the Must Supplementation with Mineral Salts

“…In other ciders the obtained isobutanol values were similar to those obtained by Loira et al [ 60 ]. This shows that not only the yeast strain used has a significant impact on the concentration of volatile compounds, but also that the addition of minerals contributed to obtaining a similar value of higher alcohols in the analyzed ciders compared to the results obtained by other researchers [ 61 ]. Magnesium ions play a fundamental role in the growth and metabolism of yeast cells.…”

Biotechnological Importance of Torulaspora delbrueckii: From the Obscurity to the Spotlight

“…In recent years, researchers worldwide have been paying particular attention to T. delbrueckii exploitation to improve wines organoleptic final profile and quality. As referred above, its physiological and metabolic properties revealed positive effects in wines characteristics towards acids and sugar consumption, but also an enhancement of the aroma complexity through the production of important metabolites [ 2 , 3 , 4 , 23 , 56 , 57 , 58 , 59 ]. During wine fermentation, higher alcohols (also termed fused alcohols) and esters contribute 30 to 80% to the aroma profiles of wine, being the two most relevant groups of metabolites [ 59 ].…”