The production of reduced-alcohol wine using glucose oxidase

232 Pages·2009·18.25 MB·English

by  Gary James Pickering

Lincoln University Digital Thesis 

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thesis.
THE PRODUCTION OF REDUCED-ALCOHOL WINE
USING GLUCOSE OXIDASE
A thesis
submitted in partial fulfilment
of the requirements for the Degree of
Doctor of Philosophy
at
Lincoln University
by
Gary James Pickering
Lincoln University
1997
Errata
• page 3 Table 1.1: "freeze concentration" change to "freeze concentration
and fractionation"
• page 11 Paragraph 2: delete sentence "Copper ions .... (Scott, 1975b) ".
• page 49 Paragraph 2: replace sentence" It is noteworthy ... butyrolactone "
with "It is noteworthy that both 2(5H)-furanone and 4-ethyI­
cyclohexanone contain carbonyl groups ".
• page 49 Paragraph 3: replace sentences "Acetates ... (Rapp, 1988) " and
" Subsequent ... esters" with "Acetates and fatty acid esters are both
synthesised by yeast during fermentation, and subsequent esterification
reactions can occur between the fatty acids and alcohols to form
fatty acid esters (Rapp, 1988) ".
• page 52 Paragraph 3: replace value 220% with 120% in sentence" Clearly
this ... GOX ".
• page 61 Paragraph 2: delete word" UV " from sentence" Wine browning was
measured by UV absorbance ... ".
• page 135 Paragraph 2: replace sentence" Intensity maxima ... attribute" with
" Wines of 7-14% ethanol were not statistically differentiated for either
attribute, although a suggested intensity maxima for viscosity and
density occurs at ca. 10 and 12 % v/v ethanol concentration respectively".
I .
04 '997
1u1t'-L-' 1.,
RECEIVED ON
o<-!~BUFiY, NEW ZEALAND
LINCOLN Animal and Veterinary
Sciences Group
P.O. Box 84
UNIVERSITY Lincoln University
Canterbury
Te Whare Wiina!!a 0 Aora!!i New Zealand
Telephone:
(64)(3) 325 3803
Fax:
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CERTIFICATE
This is to certify that Gary James Pickering produced his thesis entitled
liThe production of reduced-alcohol wine using glucose oxidase",
A ' \-\ed.q~~~
::0 .
Dr D A Heatherbell
Reader
Wine Science
31 January 1997
iii
To
my wife
iv
Abstract of a thesis submitted in partial fulfilment of the
requirements for the Degree of Doctor of Philosophy.
THE PRODUCTION OF REDUCED-ALCOHOL WINE
USING GLUCOSE OXIDASE
by Gary James Pickering
In small scale trials, a process for the glucose oxidase (GOX) - catalysed oxidation of
glucose in grape juice was developed and optimised. Up to 87% utilisation of glucose was
achieved, producing wines of ca. 6.4% alcohol. This equates to a 40% reduction in alcohol
content compared with conventionally processed wine. The effect of GOX- processing on the
compositional, stability, and sensory properties of MuUer-Thurgau and Riesling wines
was investigated.
Large amounts of gluconic acid are fonned during GOX -treatment of juice, and a large portion
of this is retained in the finished wine. In general GOX wines contained a higher concentration
of esters and fatty acids, possibly due to alterations in juice amino acid composition.
Relatively little change was observed in the concentration of the other volatile
compounds. GOX wines show increased S02-binding power compared to control wines.
GOX wines also had a more golden colour, possible due to increased quinone production
and regeneration of oxidisable phenolic substrate. They were stable against browning after
six months of bottle age, whereas control wines continued to brown throughout the two
year period of monitored aging. GOX wine appeared to be stable with respect to
'pinking' reactions and other parameters examined. Although heat/cold tests suggest they
are at more risk of developing a protein haze, no haze was observed.
GOX-treatment.of Riesling juice significantly modified the taste and appearance attributes
of the resultant wine, while other flavour parameters were relatively unaffected.
v
The exceptions were fruit aroma intensity and length of flavour, which were generally
decreased in GOX wines primarily due to the juice aeration required during processing.
Perceived viscosity and density were relatively unchanged in GOX wines, probably due to
the high acidity which itself is a detracting characteristic.
The effect of ethanol on the perception of fullness in white wine was investigated using a
time-intensity methodology. A general pattern of increase in perceived viscosity and
density occurs with increasing alcohol content up to 10 and 12% alcohol v/v respectively.
The results support the anecdotal evidence that low-alcohol wines generally have reduced
fullness compared with 'full-strength' wines, but this may not hold for wines above 12%
and possibly 10% alcohol content. These findings raise some interesting questions on
desirable alcohol levels for wine in general. In addition, the temporal parameters important
in explaining perceived viscosity and density in white wine were determined.
KEYWORDS: Reduced-alcohol wine, low-alcohol wine, glucose oxidase-catalase,
reduced sugar grape juice, juice oxidation, time-intensity, mouthfeel,
body, weight, viscosity, fullness.
vi
A glass of good wine is a gracious creature,
and reconciles poor mortality to itself,
and that is what few things can do.
-Sir Walter Scott
CONTENTS
ABSTRACT iv
CONTENTS vii
LIST OF TABLES xii
LIST OF FIGURES xiv
LIST OF APPENDICES xvi
CHAPTER 1· INTRODUCTION ____________ 1
1.1 Introductory comments 1
1.2 Review of Literature 2
1.2.1 Methods for producing low-alcohol wine 2
1.2.1.1 Technology 2
1.2.1.2 Sensory considerations 8
1.2.2 The glucose oxidase/catalase system 10
1.2.2.1 The Enzymes ______________ 10
1.2.2.2 General applications ___________ 12
1.2.2.3 Use in grape juice and wine 13
1.2.3 Perceived viscosity and density in wine _________ 17
1.2.3.1 Perceived viscosity and density_ ________ 17
1.2.3.2 Fullness in alcoholic beverages 19
1.2.3.3 Time-intensity methodology _________ 20
1.3 Summary 22
CHAPTER 2 . PROCESSING TRIALS 23
2.1 Introduction 23
2.2 Enzyme dose 23
2.3 pH and pH adjustment 24
2.4 Oxygen availability 25
2.4.1 Sparging trial 26
v
2.4.2 Aeration trial 26
2.5 Temperature trial 27
2.6 Sulphur dioxide 28
2.7 Optimised GOX process and its effect on basic
physical and chemical parameters of grape juice 29
2.8 Summary and conclusions _______________ 30
CHAPTER 3 -THE COMPOSITION OF REDUCED-ALCOHOL WINE
PRODUCED FROM GLUCOSE OXIDASE-TREATED JUICE 31
3.1 Introduction 31
3.2 Materials and methods 32
3.2.1 Processing of grape juice and wine 32
3.2.2 Analysis 33
3.2.2.1 Organic acids, sugars and alcohols 33
3.2.2.2 Acetic acid 34
3.2.2.3 Volatile constituents 35
3.2.2.4 Brix, pH, titratable acidity and sulphur dioxide __ 35
3.2.2.5 Colourlbrowning 35
3.2.2.6 Phenolics 36
3.2.2.7 Specific gravity and viscosity 36
3.3 Results 37
3.4 Discussion 44
3.4.1 Vinification observations 44
3.4.2 Organic acids, sugars and alcohols -HPLC 44
3.4.3 pH and titratable acidity 48
3.4.4 Volatile compounds -GC-MS 48
3.4.5 Phenolic changes 50
3.4.6 Colour 53
3.4.7 Viscosity and specific gravity 56
3.5 Summary and conclusions 57
CHAPTER 4 -THE CHEMICAL AND PHYSICAL STABILITY OF
REDUCED-ALCOHOL WINE PRODUCED FROM GLUCOSE
OXIDASE-TREATED JllCE 59
4.1 Introduction 59
4.2 Materials and methods 60