Fruit products containing lactic acid and process for the lactic acid fermentation of fruit products

A process for the lactic acid fermentation of fruit products is disclosed wherein an initial product in the form of a mash or juice having a pH of less than 3.7 is pasteurized and thereafter subjected to fermentation by lactic acid producing bacteria which produce at least 95% L(+) lactic acid as the fermentation product.

The invention relates to a process for the lactic acid fermentation of 
fruit products, in which the initial product in the form of a mash or 
juice, after destruction of the wild microflora therein, is subjected to 
fermentation by lactic acid producing bacteria, which produce at least 95% 
L(+) lactic acid as the fermentation product. 
The method of the present invention can advantageously utilize juices 
derived from fruits as starting materials as well as other starting 
materials obtained from fruit, which exhibit a pH value of less than 3.7. 
Among suitable fruits that can be used according to the present invention 
are well known fruits which have a relatively acidic taste such as apples, 
white and red wine grapes, apricots, sour cherries, peaches, pears, 
oranges, black and red currants and the like. 
According to the present invention, starting materials such as juices, 
nectars, mashes, pulps or other mixtures are produced from such fruits. 
Juices include clear as well as cloudy juices which are obtained by 
pressing or squeezing these fruits. 
As used herein, the term "nectar" which has a recognized meaning under the 
food laws of some countries, is understood to include fruit nectar or 
fruit syrup; that is, unfermented but capable of fermentation through the 
addition of water and/or sugar to optionally concentrated fruit juices or 
optionally concentrated fruit pulp or a mixture of such products, whereby 
these produced substances corresponding to the indicated criteria are 
defined by a minimum fruit content and a minimum acid content. 
Accordingly, a nectar obtained from black or red currants should have a 
fruit content of at least 25 weight percent and an acid content of at 
least 8 parts per 1000 (calculated as tartaric acid), that is 8 g/l of 
nectar. Similarly, a sour cherry nectar should contain at least 35 weight 
percent fruit content and 8 parts per 1000 of acid; apricot nectar should 
contain at least 40 weight percent of fruit content and at least 6 parts 
per 1000 of acid; and a peach nectar should contain at least 45 fruit 
content by weight and at least 3 parts per 1000 of acid. 
The carrying out of the process of the invention is, of course, not limited 
to the utilization of such nectars. Thus, the process of the present 
invention as described herein is also suitable for nectars which have 
other characteristics such as a higher or lower fruit and/or acid content. 
As has been mentioned, the method of the present invention can also utilize 
as the starting material a fruit pulp. In this application, the expression 
"pulp" is intended to include the edible portion of peeled and cored fruit 
which, through a variety of different processing steps have been converted 
into a pulp. 
Within the context of the invention, fruit products are understood to 
include fruit juices, fruit juice mixtures, fruit pulp, fruit pulp 
mixtures, and mixtures of the above mentioned four components, which may 
also contain admixtures of water, sugar, honey, etc. The scope of the 
meaning of "fruit products" also includes jams, preserves, fruit bars, 
jellies, spreads and the like in which the basic component is a fruit 
pulp. 
Lactic acid producing fermentations have long been known in the art. As a 
single example thereof the preparation of sauerkraut can be mentioned. In 
the past, lactic acid fermentation was mainly used to render certain moist 
articles of consumption less perishable. Later on, the object of lactic 
acid fermentation was also to improve the nutritive values and sensory 
properties of largely vegetable mashes and juices by a better digestion of 
the foodstuff and by the resulting acids. In many cases, however, 
undesirable by-products that call into question the sensory gains sought 
through fermentation also arise in conventional heterofermentative lactic 
acid fermentation. 
In recent times, an ever increasing importance has been attached not only 
to an acidulation of the product by the production of lactic acid as such 
during the lactic acid fermentation, regardless of whether the acid is 
levo- or dextrorotatory, but rather to the formation of the 
physiologically active L(+) lactic acid. To this end, special 
homofermentative bacterial cultures were selected that are capable of 
producing essentially L(+) lactic acid. 
The presence of L(+) lactic acid in almost all organs and tissues in the 
human body substantiates its importance for cell reactions. The higher the 
energy output of an organ, the greater the L(+) lactic acid requirement. 
Therefore, a balanced metabolism always requires a potential of L(+) 
lactic acid, which maintains the functions of the organs and tissues, 
especially of muscles, liver, and heart. The supply of L(+) lactic acid in 
the typical daily diet is generally below metabolic requirements of this 
substance, so it is desirable to enrich these foods with L(+) lactic acid 
from which L(+) lactic acid is immediately available for metabolism. 
A process suggesting this direction is described in German Pat. No. 2 001 
874, which has as its object the preparation of lactic acid vegetable or 
fruit juices. In this patent, four special bacterial strains are 
described, including Lactobacillus casei, which are used to ferment 
vegetable or fruit mashes or juices after destruction of the wild lactic 
acid producing bacteria found therein, a process during which lactic acid 
is produced, at least 90% of which consists of L(+) lactic acid. Examples 
given in this prior publication are the fermentation of carrot mash, 
carrot juice, red beet juice, and banana mash. Without exception, these 
mashes and juices are products with a very low initial acid content, i.e., 
a pH between approximately 5.0 and 6.0. The fermentation is carried out 
specifically to acidulate the products and, according to the details given 
in the above patent, it reaches a final pH of approximately 3.7 to 3.9 
after a fermentation time of 12 to 20 hours. According to the tables 
following the specific examples, even somewhat lower pH values were 
obtained after a fermentation time of 24 hours with certain mixtures of 
bacterial cultures indicated therein. However, these examples also suggest 
that the ratio of L(+) lactic acid to D(-) lactic acid shifts considerably 
with increasing fermentation time and lower pH values, so that in one case 
a content of up to 90%, while in other cases only 50% to 60%, L(+) lactic 
acid is obtained. 
Another feature of the process known from the prior art is that microbial 
growth occurs in the product being fermented. Admittedly, the 
microorganisms, which are then used to inoculate the main batch, are 
previously enriched in smaller amounts of the same product, but this 
amount of inoculant is basically just large enough to initiate further 
growth of the microorganisms in the main batch; the fermentation thus 
proceeds with a very active microbial growth. In this process, growth 
by-products may appear, which, under certain circumstances, are 
detrimental to a perfect sensory result. 
Another bacterial strain, Lactobacillus bavaricous, for the lactic acid 
fermentation of plant materials is described in German Pat. No. 24 40 516. 
The specific examples described therein are concerned with the preparation 
of sauerkraut and pickles. The pH after 20 days is 3.9 to 3.8. 
The present invention has as its object the provision of a process for the 
lactic acid fermentation of fruit products, which enables the production 
of appreciable amounts almost exclusively of the physiologically active 
L(+) lactic acid in fruit products, whose initial acidity is already 
relatively high, by fermentation without deleteriously affecting the 
sensory qualities of the products, but rather improving them as much as 
possible. In this process, the question is not to achieve a certain 
acidulation of a slightly sour initial product for sensory reasons, as is 
the case in conventional processes, but rather to convert a portion of the 
substances in the naturally already rather sour initial fruit into L(+) 
lactic acid without appreciable growth of the bacteria during further 
degradation of the sugar ingredients in the juice. 
It has now been unexpectedly found that the starting fruit products that 
exhibit an initial pH value of 3.7, or even preferably 3.2 to 3.6, can be 
treated with lactic acid producing bacteria. Under these conditions, it 
has been found that in a large predominant amount, the malic acid content 
of such fruit products is converted into lactic acid. 
According to the invention, the aforementioned object is achieved by 
employing bacteria whose lactic acid producing metabolic pathways are 
induced and which function even at pH values below 3.7, and by carrying 
out the fermentation at pH values below 3.7, during which process a 
portion of L(+) lactic acid of at least 95 weight percent is produced. 
Generally, a pH of a minimum of 3 is necessary in order to avoid adversely 
affecting the microorganism. Advantageously, the starting fruit products 
exhibit a pH in the range of 3.2 to 3.6. 
It has been shown that during lactic acid fermentation at pH values below 
3.7 certain sugars are not only fermented to lactic acid, but a portion of 
the organo acids, especially malic acid, found in the initial products, 
are also converted to lactic acid by the bacterial strains used. A sensory 
gain is thereby achieved to a certain extent, because the malic acid with 
its more acidic taste is replaced by the milder lactic acid with its more 
pleasant sensory effects. Therefore, the fermentation product in general 
does not exhibit any detectable malic acid content with any certainty, 
advantageously it contains a malic acid content of not more than 0.1 g/l, 
particularly not more than 0.2 to 0.5 g/l. With undiluted starting fruit 
products, according to circumstances, a malic acid content can achieve a 
maximum of 1 g/l. A corresponding higher value can naturally arise with 
further processing of the fermentation product to produce an end product, 
when the fermentation product is concentrated or is mixed with an 
unfermented starting material. 
For undiluted fruit mass (juice or pulp), the following indicated content 
values for malic acid content are indicated: oranges 1-2 g/l, apples 4-5 
g/l, grapes 4-5 g/l, peaches over 2 g/l, apricts 4-5 g/l and sour cherry 
juice 17 g/l. With these starting substances, a wide ranging elimination 
of the malic acid content takes place. As an exception, the juice and 
nectar of black currants exhibit a very low content of malic acid. The 
acidulation of quite a few citric acid containing products, such as peach 
pulp, is also desirable, during which process the L(+) lactic acid is 
synthesized from sugar. 
Preferably, the fermentation process is carried out in such a way that at 
least 5 g, preferably 6 g/l, of L(+) lactic acid is produced per liter of 
fermentation product. It is possible, however, to attain higher lactic 
acid levels depending on the raw material and process conditions. If these 
higher lactic acid levels are not required, the fermentation product can 
later be adjusted to a content of 5 g per liter with the unfermented 
product. 
As described in accordance with the process herein, the pH value of the 
obtained product is maintained under a pH of 3.7, preferably in a range of 
3.0 to 3.6, especially 3.1 to 3.4. Conversion of the malic acid, which is 
a weaker acid than the lactic acid, causes the resulting product to 
regularly exhibit a somewhat higher acidity than the starting material; 
that is, the pH value of the resulting product is usually somewhat lower 
than the pH value of the starting substance. For the reason that, as a 
general rule, the naturally occurring juices exhibit a high buffering 
capacity, the final pH value can correspond to the pH value of the 
starting substances. During the fermentation, the pH value can even rise 
by about 0.1, whereby it can be determined that according to the 
invention, the starting pH value is regularly from 0.1 to 0.2 points 
higher than the pH value at the end, as has been previously explained. 
A particularly preferred embodiment of the process of the present invention 
resides in the addition of the bacteria; i.e., the biomass, as a pure 
culture concentrate to the initial product to be fermented. The snowball 
system of microbial enrichment in the product to be fermented is 
undesirable due to its sensorially negative effects particularly in fruit 
juice products. Therefore, according to the invention, amounts that are 
appropriate for the fermentation of the selected microorganisms are added 
to maintain the target amount of L(+) lactic acid as a metabolite of the 
organisms. 
In the final analysis, no microbial growth occurs in the process taught by 
the present invention. On the contrary, the death rate lies in the 50% 
range. When the fermentation is completed, about 1/3 to 2/3 of the 
initially added amount of living biomass is still present in the product. 
In a preferred embodiment of the the present invention process, the 
remaining biomass is removed from the product at the end, because the 
fermentation products so obtained are the actual goal sought by the 
process of the invention. This removal of the biomass is especially 
desirable during the preparation of clear fruit juice products. On the 
other hand, it is not detrimental to the process results if, dependent 
upon the type of desired end product, the residual amount of biomass 
remaining after fermentation is left in the product. 
The bacterial strains are cultured in a separate, known fermentation 
process under optimum nutrient and growth conditions, as will be described 
in greater detail hereinbelow. 
Accordingly, at least 1 g, but usually 2 to 10 g, of moist purified biomass 
is to be added per liter of the initial product to be fermented. For 
reasons of economy, the added amount will essentially vary from 2 to 6 g. 
The amounts indicated herein refer to a purified bacterial mass of 21-25%, 
generally about 23%, solids. The bacterial count is about 10.sup.12 per 
gram of this biomass. 
The duration of the fermentation time for the process being described is 
generally at least 24 hours, but this can be increased to 96 to 100 hours 
in special cases. The optimum fermentation time is determined by economic 
considerations with respect to the biomass added and the fermentation 
temperature selected. The latter can range from 15.degree. to 40.degree. 
C.; with temperatures between 25.degree. C. and 35.degree. C. being 
preferred. However, in the case of particularly sensitive products, it may 
be desirable for the fermentation to proceed at a temperature below 
20.degree. C., for which reason the bacterial strains employed are also 
suitable for this purpose. 
Several suitable bacterial strains were selected or isolated for the 
process described herein. A microorganism of the genus Lactobacillus 
isolated in this regard and suitable for carrying out the process was 
given the designation Lactobacillus sp. In the research carried out, this 
strain was identified as Beta 8. Cultures of this organism were filed 
under the deposit No. DSM 3174 in the German Collection of Microorganisms 
(DSM) in Goettingen. This microorganism was selected from orange juice, 
then initially cultured on Rogosa agar and transferred to MRS broth 
(obtained from the OXOID company under the article number CM 359). 
These are motile lactobacilli with mesodiaminopimelic acid in their cell 
wall. The strains differ from the known Lactobacillus species with these 
characteristics (L. aqilis, L. yamanashiensis and L. ruminis) in a number 
of characteristics such as growth temperature, gluconate utilization and 
the base composition of the DNA, so that this is a representative of a 
species not previously described. 
Lactobacillus sp. consists of gram positive rods and is nonsporing. It is 
catalase- and nitrate-reductase negative. It is a facultatively anaerobic 
strain. The microorganisms are homofermentative; glucose is fermented 
solely into lactic acid. The resulting synthesized lactic acid consists of 
95 to 99% of the L(+) component. 
Ribose, mannitol, sorbitol, maltose, sucrose, cellobiose, trehalose, 
salicin, and glucose are fermented into lactic acid by this Lactobacillus. 
No lactic acid is produced from arabinose, xylose, rhamnose, lactose, 
melibiose, raffinose, and melezitose. Growth of the new bacillus is 
positive at 15.degree. C. and negative at 45.degree. C. Gas evolution from 
gluconate is positive. 
Lactobacillus sp. for carrying out the present invention is cultured in MRS 
broth. 1 g of biomass per liter of broth produces a 15-fold increase in 
the biomass after 24 hours at 33.degree. C. A BETA nutrient solution is 
introduced aseptically into a commercially obtainable laboratory 
fermentor; the biomass yield relative to the nutrient solution is 
considerably increased by the concurrent addition of a pH-regulating 
solution (4M NaOH) and a glucose solution of defined concentration 
(40.degree. Brix). The BETA nutrient solution employed has the following 
composition: 
TABLE 1 
______________________________________ 
Composition of the BETA Nutrient Solution 
(amounts required for 1 liter of nutrient solution) 
______________________________________ 
Peptonized milk 10.00 g 
Yeast extract 12.00 g 
Dextrose 20.00 g 
Tween 80 (surfactant) 1.00 g 
Potassium phosphate 2.00 g 
Sodium acetate 5.00 g 
Diammonium hydrogen citrate 
2.00 g 
Magnesium sulfate .times. 7H.sub.2 O 
0.20 g 
Manganese sulfate .times. 4H.sub.2 O 
0.05 g 
______________________________________ 
The microorganisms are harvested and collected by a membrane separation 
procedure. The biomass thus obtained is purified with physiologic saline 
and added as a pure culture to the fruit products. Such separation and 
purification methods are well known and any suitable procedure may be used 
for purposes of this invention. 
For the fermentation of fruit products, this biomass is added to, for 
example, apple juice, peach nectar, or cherry nectar. The process 
conditions are to be defined in detail for each individual product on the 
basis of sensory and economic interests within the limits indicated above. 
It has been found that certain other bacterial strains are also suitable 
for the present process. Thus, for example, the microorganism 
Lactobacillus casei subspecies casei as filed under deposit No. DSM 3173 
in the German Collection for Microorganisms (DSM) in Gottingen is also 
suitable. This strain was identified by the designation Beta 3 for this 
research. 
These are gram-positive nonmotile rods, 0.8 to 2-3 .mu.m in size, usually 
found in chains. They are nonsporing, facultative anaerobes, 
homofermentative, and inevitably saccharoclastic; the end product of 
glucose fermentation is strictly lactic acid L(+) lactic acid is produced 
almost exclusively. 
The bacterium is catalase- and nitrate reductase-negative. Growth occurs 
between 15.degree. C. and 45.degree. C. Gluconate is utilized. Acid is 
produced from ribose, mannitol, sorbitol, glucose, maltose, lactose, 
sucrose, cellobiose, trehalose, and salicin. No acid is produced from 
arabinose, xylose, rhamnose, melibiose, and raffinose. 
The peptidoglycan of the cell wall contains no diaminopimelic acid. Of the 
few selected strains, out of a total of over 100 tested types which are 
suitable for the above described process, the two strains described herein 
were found to exhibit particularly advantageous sensory properties. 
Some typical process results are summarized in Table II, which contains a 
range of preferred products. For the experiments, both the Beta 8 and the 
Beta 3 strains were used. The differences between the two bacterial 
strains was essentially in a sensory nature. 
TABLE II 
__________________________________________________________________________ 
Fermentation 
L(+) lactic 
Biomass conditions acid produced 
inoculum 
pH before 
pH after 
time Temp. 
L(+) lactic 
Proportion 
Product (g/l) 
fermentation 
fermentation 
(h) (.degree.C.) 
acid (g/l) 
(%) 
__________________________________________________________________________ 
Apple juice, 
3.0 3.4 3.4 72 33 7.8 96 
naturally cloudy 
Apple juice 
3.0 3.6 3.4 72 33 7.5 99 
Grape juice, 
6.0 3.4 3.4 72 33 6.8 96 
white 
Grape juice, 
6.0 3.4 3.2 72 33 7.0 96 
red 
Orange juice 
6.0 3.6 3.2 72 20 7.2 95 
Peach nectar 
3.0 3.5 3.2 48 33 5.7 95 
Apricot nectar 
3.0 3.4 3.3 48 33 5.5 95 
Cherry nectar 
3.0 3.4 3.3 48 33 9.7 98 
Black currant 
6.0 3.3 3.1 72 33 5.2 96 
nectar 
__________________________________________________________________________ 
TABLE III 
__________________________________________________________________________ 
Analytical Data for Lactic Acid Fermented Products 
Naturally cloudy apply juice 
Peach nectar 
Grape juice, white 
0-test 
ferm. test 
0-test 
ferm. test 
0-test 
ferm. test 
__________________________________________________________________________ 
Sugar content 
.degree.Brix 
12.0 11.9 15.1 
15.0 17.0 
16.8 
pH 3.3 3.4 3.6 
3.4 3.6 
3.6 
Total acid* 
g/l 
7.3 4.6 3.1 
6.0 7.9 
7.1 
L(+) lactic acid 
g/l 
-- 7.0 -- 6.1 -- 5.7 
D(-) lactic acid 
g/l 
-- 0.1 -- 0.3 -- 0.1 
Malic acid 
g/l 
7.3 n.d. 1.8 
n.n. 5.0 
0.1 
Citric acid 
g/l 
0.2 0.1 1.8 
1.6 0.4 
0.3 
Glucose g/l 
25.4 20.9 43.5 
39.1 90.2 
75.8 
Fructose g/l 
64.8 58.3 43.3 
38.8 89.5 
76.9 
Sucrose g/l 
22.0 20.0 44.0 
44.0 n.n. 
n.n. 
Biomass inoculum 
g/l 
-- 3.0 -- 3.0 -- 3.0 
Fermentation time 
h -- 72 -- 48 -- 66 
Fermentation temp. 
.degree.C. 
-- 33 -- 33 -- 33 
__________________________________________________________________________ 
n.d. = not detectable 
*calculated as tartaric acid for apple juice, as citric acid for peach 
nectar, as tartaric acid for grape juice 
The table shows that for all the fruit juice products enumerated above, the 
required characteristics, namely at least 95% L(+) lactic acid referred to 
the total lactic acid, is attainable in absolute amounts of L(+) lactic 
acid of at least 5 g/liter during fermentation below pH 3.7. The other 
process conditions are to be adapted to the special initial products 
within the limits claimed. As apparent from the table, certain juices 
require a greater amount of biomass incculum and about 50% longer 
fermentation time. 
Table III, herein below, gives details for three products about the changes 
in the acid and sugar levels occurring during fermentation.

Described in further detail, FIG. 1 shows the content of L(+) lactic acid 
and the total acid, calculated as tartaric acid, as a function of the 
fermentation time for cherry nectar and apple juice for an inoculum of 3 g 
of biomass per liter of juice product. Accordingly, the required L(+) 
lactic acid content for apple juice is attained only after a fermentation 
time of about 30 hours, whereas this occurs as early as approximately 13 
hours for cherry nectar. The graph also shows that very long fermentation 
times produce no additional major increase in L(+) lactic acid. 
FIGS. 2 and 3 show the attainable L(+) lactic acid content first for apple 
juice, then for apricot nectar for different amounts of biomass inoculum. 
The following examples serve to illustrate the present invention. 
EXAMPLE 1 
Lactic Acid Fermentation of Naturally Cloudy Apple Juice 
(a) Culturing of biomass 
The lyophilized bacterial culture is suspended in physiologic saline and is 
transferred to 50 ml of MRS broth. After 24 hours at 33.degree. C., the 
entire first culture is incubated in 500 ml of MRS broth for 24 hours at 
33.degree. C. This produces about 7.5 g of biomass. The biomass thus 
obtained is harvested under sterile conditions and used as the fermentor 
culture. BETA nutrient solution is introduced aseptically into the 
fermentor. For inoculation, 1 g of the biomass from the second culturing 
per liter of broth is used. A biomass yield of about 55 g/liter is 
obtained by the concurrent addition of a pH-regulating solution and a 
glucose solution of a specific concentration. 
After culturing is completed (24 hours at 33.degree. C.), the fermentation 
solution is placed in a sterile container, and the biomass is collected 
from the spent nutrient solution under sterile conditions by a membrane 
separation procedure. The lactobacilli are purified in physiologic saline 
and again separated. The biomass is a white, highly viscous mass and 
constitutes a pure culture. Membrane separation procedures are known in 
the art and any suitable method may be used. 
(b) Procedure for carrying out the fermentation 
Naturally cloudy apple juice with a pH of 3.4 is introduced in the amount 
of 100 ml into a sterile tank via a plate heat exchanger (HKZE 90.degree. 
C.), HKZE=high short time heating. Inoculation is performed with 3 g of 
the biomass obtained in (a) above containing 3 g/l juice. If large 
containers are used, the juice must be stirred slowly. After 72 hours of 
fermentation time at 33.degree. C., about 7.5 g of L(+) lactic acid per 
liter is produced. The lactic acid of the juice product thus obtained 
consists of about 99 weight % L(+) lactic acid and 1% D(-) lactic acid. 
The lactic acid fermented, naturally cloudy apple juice is adjusted to 5 g 
of L(+) lactic acid per liter of end product with 50 l of unfermented 
initial product and is packaged commercially by hot bottling. Such 
bottling procedures are known in the art. The fermentation was also 
carried out using the different bacterial strains Lactobacillus casei, 
subspecies casei (Beta 3 strain), and Lactobacillus sp. (Beta 8 strain). 
The resulting properties obtained exhibited only distinctions of a sensory 
nature. 
EXAMPLE 2 
Lactic Acid Fermentation of Grape Juice 
Red or white grape juice in the amount of 10 l and a pH of 3.4 is 
introduced into a sterile tank via a plate heat exchanger (HKZE 85.degree. 
C.) and is inoculated with 6 g of biomass of the strain Beta 8 per liter 
of juice. Culturing of bacteria is performed as described in Example 1 (a) 
above. After 72 hours at 33.degree. C., 7.0 g/liter of L(+) lactic acid is 
produced; the proportion of this nutritionally and physiologically 
important L(+) lactic acid is 96%. After the fermentation the lactobacilli 
are separated by means of a separator. If this processing step is used, 
the bacteria can be reused. The fermented product is then adjusted with 4 
l of fresh juice to 5.0 g/liter of L(+) lactic acid, filtered, stabilized 
with potassium bitartrate, and subsequently bottled at 85.degree. C. 
according to HKZE. 
EXAMPLE 3 
Lactic Acid Fermentation of Peach Nectar 
Peach nectar, in the amount of 10 l are produced from peach pulp and sugar 
water in a volume ratio of 1:1, with a sugar content of 15.degree. Brix is 
then introduced aseptically into the fermentation tank via a plate heat 
exchanger (HKZE 110.degree. C.). Inoculation is performed with 30 g of the 
biomass (strain Beta 8) obtained as in Example 1 (a). After 48 hours at 
33.degree. C., the pH drops from 3.6 to 3.4. The L(+) lactic acid 
concentration is 6.0 g/liter. The lactic acid consists of up to 95% L(+) 
lactic acid and up to 5% D(-) lactic acid. 
The fermented product is blended with 2.5 l unfermented initial product to 
5 g/liter of L(+) lactic acid and bottled according to HKZE (110.degree. 
C.). 
EXAMPLE 4 
Preparation of Lactic Acid Fermented Cherry Preserves 
Cherry pulp in the amount of 10 l and 15.degree. Brix with a pH of 3.4 is 
subjected to a lactic acid fermentation, wherein the pulp is briefly 
pasturized at 85.degree. C. (HKZE 85.degree.) and then introduced into a 
sterile tank. There is then added to the pulp 6 g/l of a biomass of the 
bacterial strain Beta 3. After 72 hours fermentation time at 33.degree. 
C., there is obtained 11 g/l of L(+) lactic acid. The proportion of L(+) 
lactic acid was 98% of the total lactic acid produced in this way. 
The fermented pulp was concentrated 3 fold in a thin film evaporator and, 
with the addition of sugar and binder, mixed, sterilized and brought to 
the form of a ready to sell cherry preserve. 
When used for the manufacture of jams, fruit base, jellies, spreads and the 
like which are based on the use of fruit pulp products, the lactic acid 
product of the invention is mixed with conventional ingredients according 
to known receipes and procedures. 
It is within the scope of the present invention to provide a process for 
the production of fruit pulp and fruit juice products that have a pH of 
less than 3.7, preferably less than 3.5, and a malic acid content of less 
than 1 g/l, preferably less than 0.2 g/l. Included among such fruit 
products are fruit preserves, jellies, spreads and jams. 
Further variations and modifications of the invention will be apparent to 
those skilled in the art from the foregoing and are intended to be 
encompassed by the claims appended hereto. 
The German priority application No. P 35 03 742.3 is incorporated and 
relied on herein.