Fermentation Due: April 19th by 5:00 PM Please submit your
... 3. Why is anaerobic respiration necessary to make beer and wine? Under aerobic conditions, pyruvate
(the product of glycolysis) will preferentially transition into the TCA cycle to make energy. However, in
the absence of O2, the last step in the aerobic respiration cannot happen. Consequently, the p ...
Yeast Impact on Wine Composition: Overview
... Modification of plant components
Consumption of nutrients and prevention
of growth of other microorganisms
Creation of reductive environment
impacting a range of subsequent chemical
1. You have just finished fermenting a wine and the pH = 3.7. You
... “molecular” SO2 to protect the wine. What level of free SO2 do you have to add to
achieve the level of the molecular form desired? You can ignore the sulfite (SO3) form at
this pH as the levels will be negligible. Perform by calculation, not by chart or graph, and
give answer in mg/L. (25 pts)
SO2 ( ...
Chapter 17-Alcoholic Beverages
... The grapes are picked, crushed, and the juice is allowed to ferment.
Sulfur dioxide is introduced into the closed container to kill bacteria.
If the expressed juice is made into white wine, it is filtered to
remove the skins before fermentation.
For red wine, the skins go into the fermentation vat w ...
... Fermentations are nowadays defined as a processes that do not involve
electron transport chains that use oxygen, nitrate or other electron acceptors
Case Study I—Soy Sauce
... 2. Notice that not all grape sugar is converted to ethanol. Why not?
At some point the concentration of ethanol produced by the yeast becomes so
high that the yeast can no longer tolerate it and the yeast population dies out. If
as is the case in this graph, unutilized sugar remains when the yeast c ...
Umami taste in wine
... of wine has been referred to (Peynaud1) but never analyzed. The umami taste sensation,
derived from glutamates and 5’-ribonucleotides, is well documented as an attractive,
primary taste component of myriad food products. Preliminary research shows sufficient
levels of naturally occurring umami taste ...
VEN 124 Section IV
... compounds, especially from the
degradation of amino acids. It is likely
that some of these compounds are also
being produced during growth in wine.
High Alcohol Fermentations: How to Manage Primary and
... Refer to websites for actual protocols
Long acclimatization, build-up with sugar
Short acclimatization with high inoculation rate
How many times should you try to restart a stuck
ferment? When can you start tasting the yeast?
• Use of yeast hulls
• Addition of nutrients?
Discrimination of wine age of Chinese rice wine by
... experienced to successfully evaluate the wine age. Instrumental
methods have been utilized for wine age or vintage year
discrimination to distinguish certain chemical features, such
as phenolic compounds, amino acids, pigment composition,
flavonoids, acid, and volatile compounds. The ...
GRAPE MATURITY Section 3. pH and Acidity pH and Potassium (K
... development. Potassium (K+) is the main cation (positively-charged ion) in must
and wine (Blouin and Cruège, 2003). Potassium is absorbed by the roots and
distributed to all parts of the vine. Early in the season, when the growth rate is
high, much of the K+ accumulates in the leaves. After véraison ...
Food processing and Preservation-fermentation
... • Fermentation in food processing typically is
the conversion of carbohydrates to alcohol
and carbon dioxide or organic acids using
yeast, bacteria or combination thereof, under
• A more restricted defination of fermentation
is the chemical conversion of sugar into
ethanol. The ...
Research on Strategies for Rapid Development of Shaoxing Wine:
... of amino acid and the total content of amino acid is 6770mg/L. As contrast, the total amino acid content
of dry red wine was 1581mg/L. Further more, there were 8 kinds of amino acid belong to the special
ones that human body cannot synthesize itself and has to be taken directly from outside. This re ...
Synergistic Effects of Branched
... of BCAAs + Phe could weaken the promotion effect of
higher alcohol production induced by the single addition of
the amino acid(s). Moreira et al. (2011) also observed that
branched-chain alcohols, including isobutyl alcohol and
isoamyl alcohol, were decreased in wine supplemented with
DAP, which cou ...
Fermentation is an __________________________________________________________
_____________________________________________________. Cells performed anaerobic
fermentation long before aerobic cellular respiration occurred.
Dealcoholized red and white wines decrease oxidative stress
... In vitro experiments have demonstrated that polyphenols exhibit antioxidant and anti-inflammatory activities. The present study was designed
to test whether dealcoholized red (DRW) and white (DWW) wines can decrease the oxidative stress associated with inflammation in vivo.
Rats were fed for 15 d ei ...
... other than oxygen as the terminal electron acceptor under anaerobic conditions
Fermentative process : ATP generation through SLP with the oxidation of
electron donors coupled to the reduction of electron carriers such as NAD(P)+
or flavin adenine dinucleotide (FAD). The reduced electron carriers ( ...
P_14 Enhancement of Bioactive Compounds of Roselle Vinegar by
... fermentation. Methods: Vinegar fermentationis a two-step process: First, the anaerobic conversion of
sugars to ethanol by Saccharomyces cerevisiae TISTR5048 and then the aerobic oxidation of ethanol
to acetic acid by mixed culture of Acetobacter aceti TISTR102 and Acetobacter cervisiae TN4497.
Vitis 36 (1), 43-47 (1997) Effects of maceration on the - Vitis-vea
... which shows the same concentration in wines from nonmacerated musts and those from a 6-h-macerated must.
Proline which slightly decreased with longer maceration
times is the main amino acid in musts and wines from
Chardonnay. It behaves unusually and is clearly different
from the other amino acids.
A wine fault or defect is an unpleasant characteristic of a wine often resulting from poor winemaking practices or storage conditions, and leading to wine spoilage. Many of the compounds that cause wine faults are already naturally present in wine but at insufficient concentrations to adversely affect it. In fact, depending on perception, these concentrations may impart positive characters to the wine. However, when the concentration of these compounds greatly exceeds the sensory threshold, they replace or obscure the flavors and aromas that the wine should be expressing (or that the winemaker wants the wine to express). Ultimately the quality of the wine is reduced, making it less appealing and sometimes undrinkable.There are many causes for the perception in wine faults, including poor hygiene at the winery, excessive and/or insufficient exposure of the wine to oxygen, excessive or insufficient exposure of the wine to sulphur, overextended maceration of the wine either pre- or post-fermentation, faulty fining, filtering and stabilization of the wine, the use of dirty oak barrels, over-extended barrel aging and the use of poor quality corks. Outside of the winery, other factors within the control of the retailer or end user of the wine can contribute to the perception of flaws in the wine. These include poor storage of the wine that exposes it to excessive heat and temperature fluctuations as well as the use of dirty stemware during wine tasting that can introduce materials or aromas to what was previously a clean and fault-free wine.