PROCESS FOR THE PRODUCTION OF CLEAR, LIGHT-COLOURED FRUIT JUICE

PROCEDE DE PRODUCTION DE JUS DE FRUITS TRANSPARENTS ET DE COULEUR CLAIRE

English Abstract

TITLE

PROCESS FOR THE PRODUCTION OF CLEAR, LIGHT-COLOURED FRUIT JUICE

INVENTORS

Thomas H.J. Beveridge
Judy E. Harrison



ABSTRACT OF DISCLOSURE

This invention relates to a process for the production of
clear, light-coloured apple and pear juices. This process essentially
comprises mashing the fruit to a purée, heating the purée briefly to
destroy enzymes such as polyphenol oxidase which cause browning, cooling
and subsequently treating with pectinase and cellobiase, together or
sequentially before separating the solid and liquid fractions resulting
therefrom to obtain a clear, light-coloured fruit juice. This juice may
further be treated with, for example, diatomaceous earth and may also be
concentrated if desired.

Claims

CLAIMS:

1. A process for the production of a clear, light-coloured fruit
juice from fruit selected from the group consisting of apples and pears
comprising:
(a) forming a purée from the fruit;
(b) heating the product of step (a) to destroy colour-contaminant
producing enzymes;
(c) cooling the product of step (b);
(d) treating the product of step (c) with a pectinase and a
cellobiase enzyme-containing composition; and
(e) separating the liquid fraction resulting from step (d) from
sedimentary materials to yield a clear, light-coloured fruit
juice.

2. The process of claim 1 wherein step (d) comprises:
(i) treating the product of step (c) with a pectinase enzyme
containing composition;
(ii) separating substantially solid and liquid fractions resulting
from step (d) (i);
and (iii) treating the substantially liquid fraction resulting from step
(d) (ii) with cellobiase.

3. The process of claim 1 wherein step (a) comprises forming a purée
in the presence of an antioxidant.

4. The process of claim 2 or claim 3 wherein step (a) comprises
forming a purée in the presence of an antioxidant selected from the group
consisting of sulphur dioxide, a non-toxic source of metabisulphite, and
ascorbic acid.

5. The process of claim 1, 2 or 3 wherein step (b) comprises heating
the product of step (a) to at least about 90°C for at least 15 seconds.

6. The process of claim 1, 2 or 3 wherein step (c) comprises cooling
to about 110°C in under about 5 minutes.



CLAIMS: (continued)

7. The process of claim 2 wherein step (d) (i) comprises treating
the product of step (c) with between about 0.01% and 0.1% vol/wt
pectinase for between about 0.5 and 4 hours at between about 20 to 60°C.

8. The process of claim 7 wherein the product of step (c) is treated
with about 0.01% vol/wt pectinase for 1 hour at 35°C.

9. The process of claim 2 wherein step (d) (iii) comprises treating
the substantially liquid fraction resulting from step (d) (ii) with
between about 0.01% and 0.1% vol/wt cellobiase for between about 0.5 and
4 hours at between about 20°C and 70°C.

10. The process of claim 8 wherein step (d) (iii) comprises treating
the substantially liquid fraction resulting from step (d) (iii) with
about 0.1% vol/wt cellobiase for 2 hours at 50°C.

11. The process of claim 1, 2 or 3 with the additional step (f) of
further clarifying the product of step (e) to yield a clearer, light
coloured fruit juice.

12. The process of claim 1, 2 or 3 with the additional step (g) of
concentrating the fruit juice.

13. The process of claim 2 for the production of a clear
light-coloured pear juice comprising:
(a) forming a pear pur?e in the presence of an antioxidant selected
from the group consisting of sulphur dioxide, a non-toxic source of
metabisulphite and ascorbic acid;
(b) heating the product of step (a) to at least 90°C for at least 15
seconds;
(c) cooling the product of step (b) to between 30°C and 40°C in
between 20 seconds and 4 minutes;
(d) (i) treating the product of step (c) with about 0.01% vol/wt
pectinase for about 1-2 hours at between 30°C and 50°C;
(ii) centrifuging the product of step (d) (i);
(iii) treating the supernatant resulting from step (d) (ii) with



CLAIMS: (continued)

13. (con't)
between 0.01% and 0.05% vol/wt cellobiase for about 2-4 hours at
about 50°C .
(e) centrifuging the product of step (d) (iii) to yield a supernatant
of a clear, light-coloured pear juice.

14. The process of claim 2 for the production of a clear,
light-coloured apple juice comprising:
(a) forming an apple purée in the presence of an antioxidant selected
from the group consisting of sulphur dioxide, a non-toxic source of
metabisulphite, and ascorbic acid;
(b) heating the product of step (a) to at least 90°C for at least 15
seconds;
(c) cooling the product of step (b) to between 30°C and 40°C in under
3 minutes;
(d) (i) treating the product of step (c) with about 0.05% vol/wt
pectinase for between 2 and 4 hours at about 30°C;
(ii) centrifuging the product of step (d) (i);
(iii) treating the supernatant resulting from step (d) (ii) with
about 0.05% vol/wt cellobiase for 2 to 5 hours at about 50°C;
(e) centrifuging the product of step (d) (iii) to yield a supernatant
of a clear, light coloured apple juice.

15. The process of claim 13 or 14 with the additional step (f)
wherein up to 0.1% wt/vol diatomaceous earth is added and the mixture
subsequently filtered to yield a clearer, light coloured juice.

16. The process of claim 13 or claim 14 with the additional step (f)
of filtering the product of step (e) through cellulose pads to yield a
clearer light coloured juice.

17. The process of claim 13 or claim 14 wherein step (e) is replaced
by filtering the product of step (d) (iii) through cellulose pads to
yield a clearer light coloured juice.

Description

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BACKCROUND OF THE INVENTION
This invention is concerned with the production of a clear
light-coloured fruit juice made from apples or pears. Prior art
processes to produce such juices, where they specify such a step, often
use a post-treatment, pre-concentration step employing carbon to lighten
the colour of the juice. The aim of most of these processes is to
produce a juice that combines good flavour and colour with efficiency of
extraction of soluble nutrient components.
L.H. Posorkies U.S. Patent 4,371,552 is related to the production
of a prune juice using cellulase and includes a heat treatment step which
is intended to disintegrate the fruit. Enzymes are applied to increase
the yield of prune juice. E. Grampp, R. Schmitt and H. Uhlig's U.S.
Patent 4,211,799 is concerned with making citrus fruit juices resistant
to flocculation on storage and comprises pectinase and bentonite
treatment steps. U.S. Patent 3,787,582 to C.W. Sanderson and W~S.
Simpson relates to tea powders and concerns the use of pectinase to
improve clarity and reduce the tendency to form a foam on reconstitution
with cold water. Canadian Patent 395,770 to A.D. Mc~arlane and M.B.
Davis concerns the employment of ascorbic acid to a pasteurized fruit
juice prior to canning. Canadian Patent 549,529 of R.P. Walrod concerns
a conditioning step comprising the addition of ascorbic acid to the juice
after pulping but before oxidation has proceeded to the stage where a
precipitate is evident in the juice. A. Yamane's U.S. Patent 3,860,726
concerns a process for the production of a digestible purée from fruit
25 containing stone cells and employs peptidase to achieve this end. J.P.
Richard's U.S. Patent 3,795,521 concerns the use o~ pectinase for a short
period at an elevated temperature (87 - 880C) on frult juice separated
from cellular debris to alter the viscosity characteristics of the
juice.
U.S. Patent 4,109,017 to E. Crampl), R. Schmitt and R. Urlaub
concerns the clarification of pressed fruit juices empLoying pectinase,
optiorlally with glucamyLase, but treating such jui(es with such enzyllles
at between 35C and 55C and subsequently settling at between 35C and
55C.
A problem that to date has not been very satisfactorily addressed
is browning o~ the juice by polyphenol oxidase found in the frllit.

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Tllermally treating the fruit mash is the only satisfactoly way of
controllirlg polyphenol oxidase. However, such therlnally treated fruit
mashes (pur~es) are very difficult to clarif`y. rhus a proces<, that can
reduce or eliminate browning and also does not render the product
difficult to clarify is de;irable.
~UMMARY
We have developed a process for the production of a clear,
light-coloured fruit juice from fruit selected from the group consistirlg
of apples or pears which cornprises:
(a) forming a purée from the fruit, preferably in the presence of
an antioxidant such as ascorbic acid, sulphur dioxide or a non-toxic
source of metabisulphite;
(b) heating the product of step (a) to destroy
colour-contaminant-producing enzymes, preferably to at least about
90C for at least 15 seconds;
(c) cooling the product of step (b), preferably to about 40C in
under about 5 minutes;
(d) treating the product of step (c) with a pectinase,
(E.C.3.2.1.15)and a cellobiase (E.C.3.2.1.21) enzyme containing
composition;
and, (e) separating a liquid fraction resulting from step (d) to yield
a clear, light-coloured fruit juice.
Step (d) may comprise (i) treating the product of step (e) with
a pectinase enzyme containing cornposition, for example, with between
25 0.01% and 0.1% vol/wt pectinase for between about 0.5 and 4 hrs at
between about 20C and 600C (preferably with about 0.01% vol/wt pectinase
for about 1 hour at 35C); (ii) separating substantial]y solid and liquid
fractions resulting frorn step (d) (i); and (iii) tr-eating the
substantially liquid fraction resulting from step (d) (ii) with
30 cellobiase, for example, between 0.01% and 0.1% vol/wt cellobiase for
betwen 0.5 and ll hours at betweerl 20C and 70C (preferably 0.10% vol/wt
cellobiase for 2 hours at 50C).
~n additional step (f) may be employed comprising adding
diatornaceous earth preferably up to 0.1% wt/vol. to the product of step
(e) and subsequently fi1tering to yield a more clear, lishk-coloured
fruit juice. Alternately, step (e) or (f) may comprise filtering the the
previous product of step through celluk)se pads. An additional step
(g) com~risi~lg

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concentrating the fruit juice may be employed directly after step (e) or
step (f).
DETAILED DESC~IPTION 0~ THE INVENTION
This invention relates to the production of clear, light-coloured
apple and pear juices and is particularly useful in the utilization of
all fruits including normally unmarketable fruit, to convert them to a
fruit juice "hich may be utilized directly or concentrated for later use.
It is desirable that such a fruit juice be clear, light-coloured or
colourless, with natural fruit flavours.
19 Example: 1
Pears pressure testing between 3 and 10 lbs (Magness Taylor
pressure tester, 5/16" probe) were mashed in a Waring [TM] blender.
Sufficient ascorbic acid was added to inhibit enzytnatic browning for 2-5
minutes. The mash (purée) was then heated to about 90C for at least
about 30 seconds to destroy polypnenol oxidase and then cooled to about
35C within about 15-20 seconds. 10 ml/kg mash of 1% Irgazyme 100 [TM]
pectinase was added, the resulting mixture incubated for one hour at 35C
and then centrifuged at 6500 g. The resultir1g supernatarlt was brought
to 50C and 1 ml/litre of Novozyme [TM] cellobiase (250 CBU/ml) added and
the resulting mixture was incubated for 2 nours. The mixture was then
centrifuged at 6500 g and 0.1% wt/vol diatomaceous earth added to the
supernatant. This mixture was then filtered through a filter coated with
diatomaceous earth to yield a brilliantly clear pear juice. This product
has been concentrated to 72% Brix without deposition of any sediment.
Example: 2
D'Anjou pears pressure testing between 2 and 5 lbs
(Magness-Taylor pressure tester, 5/16~ probe) were sequentially hammer
mi]1ed (13 mm screen) then Fitz-milled (No. 3 screen) in the presence of
sufficient ascorbic acid or potassium metabisulphite to inhibit browning
for 2-5 min. The rnash was heated to at least 90C (Cherry-Burell
Thermutator [TM] scrapped surface heat exchanger), for at least 30 sec.
then cooled to 30-Ll0C over 2-4 minutes. Irgazyme 100 r'l'M] (1% vol/wt),
10 ml/kg was added, and incubated at 30-il0C f`or 2 hrs. 'r~e enzyrned mash
was decanted at 2700 g (Dorr-Oliver Mercobowl) at a flow rate of 3-ll
litres/tninute. The supernatant was heated to 50C and 0.5 ml/litre of

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Novozyme 188 [TM] CeLlobiase (250 CBU/ml~ was added followed by
incubation for 11 hours. The flocculent precipitate was removed at 20000g
(Sorvall RC-5 [TM] and the clear supernatant filtered through cellulose
pads to yield a brilliantly clear pear juice.
Example: 3
Spartan apples pressure testing at 12 lb Magnus-Taylor, 7/16"
probe) were hammer milled (9mm holes) in the presence of sufficient
ascorbic acid or potassium metabisulphite to inhibit browning for 2-5
minutes. The mash was heated (Cherry-Burell Thermutator) to at least
90C for 26 35 sec. and then cooled to 30-35C within 2 minutes. The
coo]ed mash was treated with 0.05% (v/w) Pectinex Ultra SP [TM:I (Swiss
Ferment Ltd) and incubated 3 hrs at 30C, decanted at 2700 g (Dorr-Oliver
Mercobowl [TM]), the resulting supernatant brought to 50C and treated
with 0.5 ml/litre Novozyme 188 [TM] (cellobiase) for 2 -5 hrs. 1he juice
siphoned from the resulting precipitate had a slight haze removed by
final fiLtration through a diatornaceous earth filter. The final apple
juice was crystal clear and light pink in colour.
EY~ample: 4
Red Delicious apples were subjected to the same sequence of
treatments as was employed in example 3 and a similar 4uality of juice
obtained.




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