Note: Descriptions are shown in the official language in which they were submitted.
- 1 --
~ le present invention relates to :Eood and in particLIlar,
the production of an aseptic yoghurt product.
ACKGROUND OF INVENTION
Yoghurt is a form of fermented milk curdled -to a smooth
creamy or cus-tard-like consistency by lactic acid-produci.ng
microorganisms. The production of natural yoghur-t enta:ils the
innoculation of a fl-lid milk substrate, which may contain other
components, for example, stabi:ll7er~3 and sugar, with a beneEiciaL
culture of Lactobacillus bulgaricus and Streptocacuus Thermophilus
followed by .incubation at a tempera1:ure of about 100 - llO~F un-til
-the pH of -the substra-te is reduced to about 4.5 -to 4.3 ~hich
indicates that conversion to -the desired produc-t, yoghurt, has
been completecq. r.~e yoghurt is then cooled to inhibi-t or prevent
growth of undesirable microflora. The m.ilk substra-te, and -the
natural yoghur-t produced have a solids con-tent of about 11 - 13%
by welgh-t. The incubation may take place in the individual
containers in which the yoghurt is to be sold or may -take place in
a vat or similar vessel and when comple-te, -the yoghurt transferred
into the individual ccntainers. Fruit, Eruit preserves or other
flavourings may be added to -the plain yoghurt base. The increase
in yoghur-t consumption in re~ent years, especially in Nor-th
America, has been quite ~henomenal (for example, between 1960 and
1975 per capi-ta consumption in the United Sta-tes increased 483%).
Because of the greatly increased demand, yoghurt is now produced
on a large scale and sold in a wide variety of retail outlets,
including supermarkets, etc. ~owever, the product is highly
perishable and requires refrigeration if it is to be kept for even
].imited periods of time; the maximum shelf life for a natural
yoghurt under refrigerated conditions being only several ~eeks.
Consequently, it may only be transported -to a limited extent.
There has, therefore, not surprisingly been many attempts to treat
yoghurt so as to extend its shelf life and also render
refrigeration unnecessary. Those attempts have -taken many forms.
For example, Ferguson in U.S. Patent No. 3,080,236, produces an
ins-tant yoghurt which requires no refrigerat.ion and has a long
shelf life by implanting a culture in whole or ski.mmed milk having
the used milk solids conten-t and following incubation at about
--2--
100F for 12 hours, the yoghurt so produced is redwced in volume
by evaporation and then suhs-tantially dried in vacuum driers.
~lat product, when pcwdered is admixed wlth a variety of other
componen-ts including a minimum oE 10% of an ins~ant water soluble
starch, which is needed to provide suEficien-t body to -the
recons-tituted yoghurt, and a fat -to give the product the
appearance and taste of yoghurt. Schut in U.S. Patent No.
4,066,794 discloses a similar ins-tant yoghurt preparation where
the "body" in the reconsti-tuted yoghur-t is provided by a greater
-than 5~ by weight oE sodium alginate, a gell:ing or set-tling agent
which is said to irnpart a curd-like consistency `having thixotropic
qualities to the recon~.tituted product, as well as almos-t 70% by
weight of sugar. An alternative route to a yoghurt having an
extended shelf liEe is taught by Egli et al in U.S. Patent No.
3,932,680. That patent discloses a process which produces a
sterile yoghurt. In that process, pasteurized and homogenized
milk is concentrated 10%; lO~ to 12% of sugar is added; the
mixture cooled and incubation to a pH oE 4.0 to 4.3 is effected
using cultures of lactic acid bacteria over a period of 2.5 to 4
hours at a temperature of from 42 - 44C, the resulting yoghurt
base being cooled to between 30 - 20C. Subsequently, lt is
further cooled to a -temperature of from 12 - 4C when an effective
amount of the following stabilizers are added:
Stabiliæer A which contains by weight, 20 - 30% emulsifier; 20 -
40% carrageenan, 30 - 40% carboxymethylcellulose; 2 - 3% carob-
bean meat or powder; and 4 - 8~ guar meal;
Stabilizer B which is potato starch or other starch, and
Stabilizer C which contains by weigh-t 75 - 85% of 60% modified
gelatin and sucrose (the carrier Eor the dissolving or
distribution of protein.
The resulting mass is then allowed to stand at 4 -
l2C for 5 - 7 hours when, presumedly the yoghurt has been
produced. The yoghurt is then introduced into containers which
are hermetically ~ealed and subjected to a sterilizing procedure
involving heating the containers in an autoclave at 60 - 85C and
6 !9;~
a pressure o~ up to 2 a-tmospheres Eor a -time su~ic:ient to
s-teril:iæe -the produc-t and the packa~es, cooling under pressure to
a temperature of from 10 - 15C and, Einally, s-toring the packages
~or 2 to 4 days at a temperature of from 4 to 6~C. To say the
least, the described process is extremely complex and time
consuming, most probably to -the extent that the process cannot be
wor~sed economically on an industria:L scale. In fact, applicant
believes that there are no s-terile true yoghur-t products on sale,
at least in North America, a-t the presen-t time (several attemp-ts
to marXet such products over the last severa] years having
failed). ReEerence may be made once again to -the relatively hi~h
sugar content and also to the Eact -that cooling prior to the
thermal treatmen~ is essential if syneresis of whey in the final
product is -to be avoided. A modified embodiment of the invention
of U.S. 3,932,680 is described in U.S. ~,235,934.
There are rnany problems associated with producing a
thermally treated sterile yoghurt, the most impor-tant from a
consumer accep-tance viewpoint basic difficulty being that the
yoghur-t body or -texture consists of a delicate pro-tein matrix
which can easily be disrupted and destroyed by hea-t and also by
mechanical action such as pumping or the like required in a
commercial processing operation. In addition, hea-t treatment can
resul-t in the yoghurt's characteristic flavour can be seriously
degraded to the extent -that in many prior art thermally trea-ted
yoghurt products, Eollowing the thermal treatment, it is necessary
to include a component which imparts a "yoghurt -Elavour" to the
final product. Consequently, it is not possible merely -to
sterilize standard yoghurt and obtain a product that will be
acceptable to the consumer. As ~he prior art extensively
demonstrates, the retention of yoghurt taste and texture is
essential if an acceptable product is to be obtained and the prior
art products, leave much to be desired in one, or generally both,
of -those characteristics.
It is an object of -the present invention tG
economically provide a sterile or ascept natural yoghurt having
the taste and texture of natural yoghurt and which has an extended
shelf life without refrigeration.
G~NER~L STAI`EMENT OF INVENTION
___. __ __
It has been ~Eound that the above object can be achi.eved
if following incubation, and whilst the yoghurt base is still at
an elevated temperature, minor amounts of each of carrageenan,
citric acid, a s~arch and sugar are admixed therewith; -the
resulting mlxture is subjected to a special. time/temperature
-treatment, whereby the pro-tein is p~.e-conditioned w~ilst the
starch is subs-tantial.ly not affectecl (not gela-tinized) to any
significan-t extent, and then subjected to a one-stage
homogenization at lower than usual pressures followed by heating
to pasteurization temperatures. If desired, the usual componen-ts
which impart fruit or other flavourings, colour and the like plain
yoghurt may be added, usually following homogeni.zation and be:Eore
pasteuxization of the product.
Detailed Statement of Invention
In one aspect, the present inven-tion provides a process
for the production of an aseptic yoghurt comprising:
(a) maintaining a fluid milk substrate at an elevated
temperature for a period of time su~:Eicient to effect
pasteurization;
(b) cooling the pasteurized substra-te to an incubation
temperature within the range 100 to 115F,
~ c) subsequently innoculating said mix-ture with a
yoghurt culture producing lactic acid and incubating said mixture
until the pH is reduced to between 4.5 to ~.0 whereby a yoghurt
base is produced;
(d) admixing with said yoghurt base whilst still at an
elevated temperature the following components:
carrageenan : from 0.1% to 0.8%
citrate ion : from 0.05% to 2.0%
starch : from 0.5~ to 2.5%
sugar : from 2.0% to 6.0% and
if required, water : in an amount such that the milk
solids content of -the -total
mixture is from 10% to 15%;
(all percentages being by weight based on the total mixture)
(e) subjecting the natural yoghurt so produced to an
elevated tempera-ture/time treatment which effects pre-conditioning
~ 5 --
of the pro-tein wllilst substan-t.ially avoicli.ng gela~:inization o.E the
s-tarch;
() homogenizing the mixtllre at a temperature of at
mos-t about 170 in only one stage and a-t a pressure of :Erom 500 to
1500 psi;
(g) op-tionally, introduc:i~g into the homoyenized
mixture :Elavour and/or aroma-imparting agen-ts;
(h) pasteruizing the resu].t.ing m:ixture at a temperature
of at east 180F; and
(i) cooling the asept.ic yoghurt so produced to a
temperatrue oE less than 85~F.
Mixing of the base yoghurt with the other cornponents in
s-tep ~d) is advantageously carried out when said components are in
the form of an aqueous slurry. This reduces -the possibility of
lumps being formed and assists in obtaining a uniform smooth
dispersion. Moreover, this allows steps (a) (b) and ~c) to be
carried out using a milk substrate having a high solids con-tent of
preferably from 15 to 20%, since upon admi.xing the water content
of the ~lurry reduces the solids content of the finished yoghurt
to -the usually desired level of from 10% to 15~. The increased
solids content means a reduction in volume being treated and
consequently smaller scale, and less expensive equi.pment may be
used. Alternatively, a greater throughput of product can be
achieved. If the components of step (d) are in dry condition
which admixed with the base yoghurt care should be taken to ensure
adequate dispersion of the solids throughout -the mass and it may
be expedient to utilize some low intensity mixing ac-tion to
achieve the desired even distribution.
In a further aspect, the present invention provides a
process for the production of an aseptic yoghurt comprising:
(a) maintaining a fluid milk substra-te ha~ing a total
millc solids content of from about 15~ to about 20% by weight at an
elevated temperature for a period of time sufficient to effec-t
pasteurization,
(b) cooling the pasteurized mixture to an incubation
temperature of :Erom about 100 to about 115~F;
~ c) subsequently innoculating said mixture with a
yoghurt culture producing lactic acid and incubating said mixture
until the pH is reduced to between about 4.5 to about 4.0 whereby
a yoghur-t base is produced,
~.a~
-- 6
(d) admi~ing with said yoghurt base whils-t still at an
alevated tempera-ture an aqueous slurry comprising the following:
carrageenan : ~rom about 0.1% to about 0.8% (preferably
about 0.1% - about 0.5%)
citrate ion : fro~ about 0.05~ -to about 2.0
starch : rom about 0.5% to about 2.5%
(prefarably about 0.5~ - about
1.5%)
sugar : from about 2.0'~ to about 6.0~
water : in an amount such that the milk
solids content o the total mixture
i5 from about 10~ -to about 15~,
(all percentages being by weight based on the total mixture)
(e) subjecting the natural yoghurt so produced to an
elevated temperature/time treatment which effects pre~conditioning
of the protein whilst substantially avoiding gelatinization of the
starch;
(f) homogenizing the mixture at a temperature of at
most about 170E' in only one stage and at a pressure of from 500 to
1500 psi,
(g) optionally, introducing i.nto the homogenized
mixture ~lavour and/or aroma imparting agents,
~ h) pasteurizing the resulting mixture a-t a temperat-ure
of at least 180F; and
(i) cooling the aseptic yoghurt so produced -to a
temperature of less than 85F;
It is also preferred that up to 0.5% of pectin be
admixed with the yoghurt base in step (d).
The product may then packed in a manner known per se
under aseptic conditions in a previously sterilized con-tainer.
The various parameters involved and the criticality
thereof to the present invention are discussed below-
Milk Substr _
It is preferable that the yoghurt produced according to
the presen-t invention have a milk solids content similar to
natural yoghur-t, i.e. between about 11% and about 15~, generally
11~ and 13~ by weight. In the production of natural yoghurt, the milk
-- 7 --
substrate usually has a total mi:Lk solids content similar to that
desired in the f:Lnal product. However, in the process of the
present invention it has been found that the various constituen-ts
detailed in step (d) above are advantageously admixed wit'h the
yoghur-t base in the form of an aqueous suspension, i.e. a further
amount of water is added to the system -thereby reducing the
percentage amount of milk solids. The best results are obtained
iE t'he milk subs-trate prior -to pasteurizatlon and innocula-tion has
a total milk solids content of from ahout lS~ to about 20~ be
weight, preferably about 17~ -to about 18% by weig'ht. That
relatively high milk solids content may be obtained ln several
ways: Eor example, i-t may be obtained by concentration of liquid
milk by vacuum evaporation or the like or, and preferably, is
obtained by adding further milk solids in the form of skim milk,
evaporate milk or the like. Usually, the further milk solids will
be added to warm (about 100F) liquid milk. The milk substra-te
will, of course, include -the usual amount of butterfat, say frorn 1
to 4% by weight.
The milk substra-te having -the above total milk solids
content is pasteurized by methods well known in -the ar-t, for
example, heating in a VAT process at 175 200F for 5 to 30
minutes, shorter times being used, of course, at the higher
temperatures. The pasteurized substra-te is then cooled to the
incubation temperature of from 95 - 115F.
Incubation
This is effected at a temperature of from about 95 -
about 115F preferably for about 2-1/2 to 4 hours using :Erom about
2% to 6~ of a standard yoghurt producing culture, namely
Lactobacillus Bulgaricus and Streptococcus Thermophilus. However,
there is nothing novel per se in the culture, amount thereof or
the general fermenta-tion conditions used. Initially, the pH of
the substrate is about 6.5 and upon completion, has dropped to
from about 4.5 to 4.0, usually to about 4.2 - 3, a value obtained
followinq about 3.5 hours fermentation. The pH will drop a little
further during the remainder of the processing; the final product
having a pH of from about 3.8 to 4.1. As a question of prac-tice,
the attainment of a predetermined pH is the indication that the
incubation stage has been completed.
- ~3 -
Additive Addition -to Yoghur-t Ba.se
The adclitives referred to in step (d) must be added, or
at least col~nenced -to be added, wh:i:lst t'he yoghurt base is at an
elevated temperature, i.e. greater than about 95 GF - 100 F,
al-though the add;-tion may be completed whilst the mi~ture is
cooling to some extent. However, addition must be substantially
complete at a -temperature of abou-t ~5F. If the col~nencement of
the addition is carried out following cooling of the yoghurt base
to below about 95F - 100F, it i.s not possible to ob-tain even
dispersion of -t'he additives throllghout the yoghurt base rnas.s and
"lumping" occurs which cannot subsequently be rernoved and hence
carries through to the then non~uniform and unacceptable final
product.
As to the function of the additives:
(i) Carrageenan - this helps to prevent aggregation of
protein, wheying off, and -to obtaining a smooth product of
sufficien-t body. Excessive amounts should be avoided since this
is counterproductive and -tends to create lumps that impair -the
texture of the product.
(ii) Citrate ion - this assists in preventing
precipitating reactions during the s-terilization, i.e. provides a
more stable protein dispersion: it functions as a pH buffer and
sequesterant for heavy me-tals. The citrate ion can be included as
a salt, such as sodium citrate or as the acid, the latter also
fulfilling the role of a pH adjuster if this is required.
(iii) Starch - This assists in the obtaining of a smooth
homogenous product having adequate body, the amount of starch
required being relatively low in view of -the effect of the special
processing conditions used.
(iv) Sugar ~ In this environment, the suyar func-tions
as an essential dispersing agent for the o-ther additives such as
the gum which assists in preventing aggregation of the protein and
also as a sweetening agent. It is present in an amount of from 3
to 6% by weight, preferably about 4~ to 5~ by weight.
As stated, the above additives are preferably added to
the yoghurt base ln an aqueous slurry, the water content of which
is calcula-ted so that upon -the slurry and the yoghurt base being
admixed, the starting total milk solids content, preferably of
from 15~ -to 20% is reduced to a predetermined value between abou-t
~z~
9 ~
10% and 15% usually between about 12 to 1~ and preferabl~ about
13~ by weight.
Processing
(a) Protein Preconditionlng
Simple heating oE natural yoghurt resu]ts in
substantially cornple-te aggrega-tion of -the protein as -the
temperature increases. This produces hard and relative]y large
lumps of pro-tein and it is practicaLly impossible to convert those
lumps to a smaller par-ticulate ~orm where Wle resulting yoghurt
product will not have an unacceptable quality or sandy mou-thfeel.
A very important feature of the present invention is the
temperature/time treatment stage in the process where the protein
is "pre-conditioned" in which form i-t can be transformed in the
next special homogeniza~ion stage, into a diminuated form which,
surprisingly, does not impart a grit-ty mouthfeel to the product:
to the con-trary, the product is smooth and creamy. It is believed
that in the pre-conditioning stage, the protein is modified
denatured forming soft curds or the like which the subsequent mild
homogenization stage is able to convert to a particular or -the
like form having no gritty mouthfeel characteristics.
A further factor which must be taken into account is the
effect of the heat treatment on the starch content.
Gela-tinization of a significant portion of the starch would make
the subsequent required treatment of the protein not possible.
According to the present invention the required pre-conditioning
of the protein can be effected without significant gelatiniza-tion
of the starch content in two ways following preparation in step
(d) of the mixture of base yoghurt and additlves:
~ a) ~le said mixture is held at a temperatue of from
140 to 155F for a period of from 5 to 20 minutes, following which
the temperature is raised as rapidly as possible to 170F when the
subsequent one stage homogenization stage (f) is ef~ected. This
procedure would generally be followed when the process of the
invention is operated as a batch process; or
(b) The temperature of said mixture is raised rapidly,
within about 60 seconds, or so, to about 170C when the subsequent
one stage homogenization stage (f) is effected. This procedure
would normally be operated in continuous process embodiments of
-the present invention.
~3~6~3~
-- lO -
Homogenization
Most prior art homogeniza-t.ion procedures utili~e a
consecutive two stage procedure involving pressures to l,.~OO -
2,000 psi or more in the Eirs-t s-tage. In contradistinction
thereto, the process of -the present invention involves a sin~le
stage homogenlza-tion which utilizes an intermediate to low
pressure of about 1,500 to 500 psi with pressures of about 750 to
l,250 psi being pre:Eerred with about. 1,000 psi being especially
preferred.
The homgenizat:ion must be eE:Eected at an elevated
-temperature of at least 1~0F, conveniently at about 150F and up
to 170F.
As mentioned previously, yoghurt is structurally a
relatively delicate product and the above relatively mild
homogenization stage surprisingly results in a product having only
a slight increase in viscosity and a smooth texture, any protein
particles being of a size and being dispersed in such a manner
that the product has a smooth mouthfeel with no gritty :Eeeling.
The standard two-stage homogeni~.ation procedure usually used,
breaks down the yoghurt product and gives a gritty mouthfeel to
the product.
Pasteurization
Following homogenization, the temperature of the mixture
is raised to effect pasteurization, this pre:Eerably being effected
in a mannex which results in as little as possible work input to
the yoghurt, tubular heat exhangers and scraped surface heat
exchanges have been found satisfactory for this purpose.
Subsequently, the -temperature is lowered to below 85F
when the mixture is aseptically packed i.nto sterilized retail-size
containers. The methods and equipment involved in s~erilizing
such containers and packing fluid products therein
under aseptic or sterile conditions are well known and widely
used. The present assignee, for example, operates a Dole Asep-tic
Line ~odel No. 520 production facility which is perfectly adapted
to being used in association with the present invention.
In common with the processing of such fluid food
products, care should be taken to use plant, for example, mixing
devices, etc. which as far as possible eliminate the introduction
of air into the product, the latter producing product instability
and also leads to mold growth and other adverse ef:Eects.
~3~
-- 1 1. `-
It may be no-ted -that it is not essent:i.al. that the
mixt~lre :Eormed by admixing the yoc3hurt base and -the stated
additives be immediately processed through the homogenization and
pasteuri~ation stages. The mixture may be cooled and subsequently
subjected to the pro-tein pre-conditioning stage, the
homogenization stage, etc. It is, however, essential tha-t the
stated additives be admixed wi-th the base yoghurt at an elevated
temperature, s-tarting at more than 100F, otherwise it is
impossible to incorporate those ingredients homogeneously
throughou-t the yoghurt mass.
In fact, -the assignee has prepared many hatches of
sterile or aseptic yoghurt accord:ing to the present invention, by
the batch process generally detai:Led above and wherein the
additives were commenced to be added to the yoghurt base at the
incuba-tion temperature and the addition, and mixing, continued as
the resulting mixture slowly cooled. The total mix-ture was
finally cool.ed to about 40F over a period of four (4) hours,
mixing of the two components having been completed within about
thirty (30) minutes or forty five (45) minutes, and beEore the
temperature had dropped to below about 85F. The present
invention will be further described, but not li~nited by, reference
to the following specific examples:
Example 1
Skim milk powder in the amount of 120 lbs. was added
with stlrring to 5,700 lbs. of whole milk (3.5% milk solids)
heated to a temperature of 100F, the milk solids content of the
mixture being about 17.8 and the butterfat content being about
2.6% The mix-ture was then homogenized and pasteurized by heating
to a temperature of 190F for ten minutes following which it was
cooled -to 110F and innoculated with 1801bs. of a culture of
Lactobacillus Bulgaricus and Streptococcus Thermophilus and the
whole mass mixed. Incubation was allowed to proceed at a
temperature of 110F until the pH had dropped :Erom the original
value of 6 to about 4.4, this taking about 4 hours. At t`hat time
the temperature was quickly raised -to
12 -
about 140F when an aqueous slurry containing the following compo-
nents was added thereto:
Citric Acid 6 lbs.
Carragenan1 8 lbs.
5ugar (powdered dextrose) 360 lbs.
Pectin2 18 lbs.
Starch3 72 lbs.
in 17 lbs. of water
1Lygomme CDS~M available Erom Frank Dempsey & Sons Ltd., Toronto
2Pectin JMT~I available from A/S Kobenhavns Pectinfabrik
3Rezista~M starch available from Staley Co.
The resulting mixture was heated fairly rapidly (over a
period of only about 15 minutes) to 160F during which the protein was
pre-conditioned, i.e. denatured to some extent so as to form soft curds
therewith) and the starch content remained practically unaltered; the
whole mixture then being subjected to a one-stage homogenization at a
pressure of 1,000 lbs., this stage lasting about 60 minutes.
The ma~erial at this stage, was of course, a plain yoghurt
base and the above procedure was used to produce a number of similar
batches which were then provided with a variety of fruit in the form of
a puree and fruit flavour addition to each batch oE one of the
following natural by fruit/fruit flavour combinations:
Strawberry
Fruit:882~5 lbs.
Naarden strawberry fruit natural Flavour 2P-3nss1 - 22.12 lbs. (0~3%)
Raspberry
Fruit 882065 lbs.
Raspberry Flavour - 11.05 lbs~ l0.15%)
, .
32
- 13 -
Peach
___--__
Fruit 882.65 lbs. (12%)
Peach Flavour 150.1 lbs. (2.0%)
Orange
Fruit 8~32.,65 lbs. (12%)
Orange Flavour 7.36 lbs. (0.1~)
The fruit wàs in the Eorm oE a puree con-taining lurnps of
the fruit. The natural fruit flavour combina-tion was admixed with
the yoghur-t and khe to-tal mix-ture heated in a permutator at 190F to
200F for about five (5) minutes which ensured comple-te pasteuriza-
tion and also full gelatinizatiorl of the small starch component,
following which the desired aseptic fruit yoghurt product was cooled
down to below 80F in preparation for packing in an aseptic packing
line. The line used in this case was Dole Aseptic Line Model ~o.
520 but it is pointed ou-t that the specific line used and the manner
of packing is not an essen-tial feature of the present invention.
Exampl~ 2
_
Skim milk powder in the amount of 1.36 kg (3 lbs.) was admixed with
stirring into 66 litres of whole milk (33 ~ milk solids) which had
been heated to 100F, the resulting mixture having a milk solids
content of about 13.7~ and a butterf~t content of 2.2~. The mixture
was pasteurized by heating at the temperature of greater than 190F
following which it was cooled to a temperature of between 100 and
110F, admixed with 1.36 kg (3 lbx.~ i.e. 2~ by weight of the
mixture, with lactobacillus bulgaricus and streptococuus thermophi-
lius culture. Incubation proceeded for about 5.5 hours during which
the starting pI~ of about 6 had dropped to about 4.15. Temperature
of the mixture was then raised to between 140 and 145F over a
period of from 20 to 25 minutes when preconditioning of the protein
occurred following which a dry mixture comprising the following
components:
~l~Z~
-- 14 -
TABLE 1
Amount (g) wt. % of mixture
citric acid 68.1 0.1
Lygomme CDSTM 190.5 0.28
sugar (powdered) dextrose 2.38 3.5
Pectin JMTM 204.3 0.3
RezistaTM Starch 8l6.6 1.2
was sprinkled thereon and the resulting mass homogenized in one-
stage homogenizer had just less than 1,000 lbs. pressure for rom
15 to 20 minutes. This produced ~8 kg (150 lbs.) of the desired
plain yoghurt base which was then heated at 190F for 2 mir.utes in
a thermotator which ensured pasteurization and also full
gelatinization of the minor starch component resulting in
development of the desired texture. The product was cooled and
packed aseptically as described in Example 1.
Obviously, if desired, the product could have been
converted into fruit-flavour products in the same manner as
detailed in Example 1.
Example 3
A batch of 53.5 kg (96 lbs.) of whole milk having a milk
solids content of 3.5% was heated to 100F and 970 g (2 lbs.~ o
2% skim milk powder added with stirring following which the
mixture was heated to 190~F for ten minutes Following
pasteurization, the mixture was cooled to 110F and 970 g (2 lbs~
of the yoghurt culture used in Example 1 mixed therein.
Incubation at 110F was allowed to continue until the pH had
dropped to 4.25, the incubation lasting 4-4~5 hours.
Separately, a drier mixture o the following ingredients
were made:
- 15 -
TABLE 2
Amount (g) wt % of mixture
citric acid 45.4 O.l
Lygomme CDSTM127 0~28
Sugar 2043 4.5
Pectin JMTM136.2 0.3
RezistaTM Starch 544 8 l.2
~ _,_ __
That mixture was warmed to 130F and sprinkled on the incubated sub-
strate, the temperature of which was then raised to 145F over a period
of some 20 minutes. During that period the required pre-conditioning
of the protein occurred. The whole mixture was then homogenized in a
one-stage homogenizing unit at a pressure of l,000 lbs. for just less
than 20 minutes and subsequently pasteurized in a thermotator unit at a
temperature of 190F for 2 minutes. Th~ product was then cooled to
below 80F taking the usual precautions to maintain the product in an
aseptic condition prior to enduring packaging.
As previously, the product produced was a plain yoghurt and
this i5 readily converted to any o the desired fruit-flavoured pro-
ducts in the same manner as described in Example l.
It will be noted that the product LYGOMME CDSTM is a
complex o red seaweeds (Gigartinaceae family), extracts and galacto-
mannans, and is an odorless, tasteless, creamy white powder which is
useful as a thickening agent in food applications. It forms a 1.0 to
1.5 XcP aqueous solution (1% wei~ht by volume, ater heating) having a
pH of between 6 and 8, measured at 20~C.
Similarly, Pectin JMTM comprises relatively highly metho-
xylated polygalacturonic acid and is useful as a stabilizer. 4% aque-
ous solutions, measured at 25C, have a pH ranging between 2.7 and 3.2.
This product meets the specifications for pectin as set out in the Food
Chemical Codex, Second Ædition, Washington, D~Co ~ 1972~
Also, RezistaT~M starch is a modiied waxy-maize starch
which is a "ood starch-modified" according to Food Additives Regula-
tion 172O82.
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