Calcium fortified acid beverages

A clear, calcium-fortified aqueous acidic beverage is provided which can contain large amounts of dietary calcium while remaining clear and storage stable even during pasteurization and refrigeration. The beverage can comprise a clear aqueous solution of an organic calcium compound such as calcium gluconate at a pH of about 4 and below wherein the calcium compound content does not exceed the solubility limit of the compound in water. An inorganic calcium salt can be used alone or in combination with an organic calcium compound to form an acidic beverage provided the pH is adjusted with an organic acid.

BACKGROUND OF THE INVENTION 
The present invention relates to a clear, calciumfortified, acidic beverage 
to be used to provide dietary calcium supplementation. 
Calcium deficiencies have been noted as a major health problem, 
particularly for women. Osteoporosis, an accelerated bone loss, can occur 
when the body is deficient in calcium. During a period of calcium 
deficiency, calcium that is needed for various body functions can be 
retrieved from bones and thereby prevent bone remodeling. Premenopausal 
adult women require about 1,000 milligrams of calcium per day (based on 
recommendations by the 1984 NIH Consensus Development Panel on 
Osteoporosis). Younger women, particularly pregnant and lactating women 
and post-menstrual women may require more. Further, adequate calcium 
intake before age 35 may lessen the effect of osteoporosis in later life. 
One of the major sources of available calcium for dietary purposes is dairy 
products. Since fluid milk provides about 300 milligrams calcium per 240 
milliliter (8 ounce) serving, the consumption of approximately 6/7 of a 
liter of milk would be necessary to provide the present minimum 
recommended amounts of calcium. As this amount of milk can be overbearing, 
it has been proposed to enrich the milk with a source of dietary calcium 
to reduce the amount of fluid intake needed to achieve a specific level of 
calcium supplement. However, many of the very people who need the calcium 
do not like the taste of milk. A calcium enriched milk is not the answer 
for those people. Further, due to lactose intolerance, milk may not be a 
practical source of calcium for some people. 
Those who cannot tolerate milk can increase their calcium intake by the use 
of tablets or capsules of calcium salts such as calcium carbonate. 
However, since the consumption of beverages other than milk, such as soft 
drinks, is common in everyday life, it would be desirable to develop a 
beverage which can be consumed as soft drinks, particularly by people who 
cannot tolerate milk. 
Calcium enhancement of dairy products can be readily achieved by 
incorporating insoluble calcium salts in the milk. The use of a suspending 
agent can prevent the insoluble compound from settling. Due to the opaque 
nature of the milk, the suspended calcium salts are hidden. Further, 
suspending agents can change the consistency of the milk and the insoluble 
calcium salts can affect mouth feel. However, such leeway is not present 
in clear beverages. 
Because a number of popular beverages are clear citrus or cola drinks are 
acidic, it would be desirable to develop a clear calcium fortified acidic 
beverage that could be utilized in the same manner as beverages commonly 
in use. Contrary to milk, a clear beverage must be storage stable for long 
periods of time and not evidence any clouding or precipitation after 
pasteurization and various heating/cooling cycles. Cola beverages which 
are characterized by a lower pH may form a more suitable base for calcium 
orthophosphates which are soluble only below pH 3. Milk systems are not as 
critical inasmuch as the opacity of the milk masks any clouding caused by 
the calcium salt. 
Because most of the calcium in the diet is excreted or lost in the urine 
and in perspiration, only about 20 percent of the calcium may be available 
for retaining the calcium balance in plasma and tissues and in bone 
remodeling. Therefore, any calcium fortified clear beverage must contain 
sufficient calcium to provide the amount needed for body functions and 
bone remodeling after losses. 
Numerous calcium supplements are presently available on the market. Calcium 
carbonate, calcium lactate, calcium gluconate and calcium glubionate are 
commonly used. Calcium carbonate has 40 percent calcium and is generally 
available in tablet form. Calcium lactate has 13 percent calcium and 
calcium gluconate has 9 percent calcium. Calcium glubionate is used as the 
calcium source in a calcium supplemental syrup for infants. Calcium 
gluconate is available as an injectable solution. The amount of calcium 
compound present in a tablet does not present the problems which arise in 
formulating a liquid beverage, particularly one that is clear and storage 
stable. In using compounds with low calcium contents, larger amounts must 
be dissolved in the beverage to attain a high level of calcium 
fortification. The prior art does not teach one of ordinary skill in the 
art the method of preparing a calcium-fortified acidic liquid, clear 
beverage. 
It would be hghly desirable to formulate a non-dairy acidic liquid calcium 
supplement which is clear and palatable and which does not develop 
aftertaste nor precipitate upon standing. 
SUMMARY OF THE PRESENT INVENTION 
A clear, storage-stable, calcium-fortified acidic beverage or a syrup for 
preparing the same is provided comprising a clear aqueous solution of 
calcium compound(s) at a pH of about 4 and below wherein the calcium 
compound is present in an amount sufficient to provide at least 300 
milligrams dietary calcium per 240 milliliters. The acidic 
calcium-fortified beverage provided is stable and palatable and does not 
develop off taste. These ends will become more apparent from the detailed 
description which follows. The beverage can be carbonated or 
non-carbonated as desired. 
DETAILED DESCRIPTION OF THE INVENTION 
The sources of dietary calcium as used in the present invention include 
food-grade calcium salts of organic and inorganic compounds. The calcium 
compounds must be capable of being solubilized such that a clear solution 
at a pH of about 4 and below can be obtained. Calcium salts which 
adversely affect flavor, calcium absorption or biological functions are to 
be avoided. Preferably, preformed calcium compounds are used but the 
invention also includes calcium compounds formed in situ. 
The inorganic calcium compounds which can be used are any food-grade 
calcium compound that is soluble and does not cause adverse flavor or 
biological problems. These salts can be illustrated by the oxide, 
hydroxide, carbonate, orthophosphate(s) (mono-, di- and tricalcium 
phosphate) with the carbonate being preferred. 
The organic calcium compounds are food-grade compounds which do not 
adversely affect the flavor or biological system. There are numerous 
organic calcium compounds used as calcium enrichers. Among the organic 
calcium compounds are calcium gluconate, calcium glubionate (a.k.a. 
Calcium D-gluconate lactobionate monohydrate), calcium gluceptate, calcium 
glycerophosphate, calcium lactate, calcium levulinate, calcium 
lactophosphate, calcium citrate, calcium acetate, calcium ascorbate, 
calcium tartarate, calcium malate and the like and mixtures thereof. Any 
of these calcium enrichers may be used as long as they do not adversely 
affect the flavor of the beverage in which they are used. 
The preferred salt is calcium gluconate. As calcium gluconate cannot be 
solubilized by heating a suspension of the compound at an acidic pH, it is 
necessary in order to form a clear beverage to presolubilize the calcium 
gluconate. The gluconate can be easily presolubilized by heating an 
aqueous dispersion of the salt at native pH (about 6-7) to a temperature 
ranging from about 50.degree. C. to about 95.degree. C. before 
acidification. The amount of gluconate is preferably below the solubility 
limit at the refrigerated temperature normally used for cooling beverages. 
Once the calcium gluconate is in solution, the pH can be lowered by the 
use of any food-grade organic or inorganic acid. 
The dissolution rate of calcium citrate has been found to be essentially 
not adaptable to forming a clear solution at native pH. A calcium salt 
neutralized by citric acid produces calcium citrate in situ in solution 
which forms crystals very slowly avoiding precipitation problems. The 
organic calcium compound must be capable of being formed into a clear, 
stable solution at acidic pH's. 
The amount of calcium compound used depends on the percentage of calcium in 
the compound(s) and the level of supplemental calcium to be dispensed per 
unit amount of the beverage. The amount of calcium compound also depends 
on the recommended daily allowance for calcium and the percentage of that 
allowance to be dispensed per unit amount of beverage. For a practical 
commercial product, 240 milliliters can be used as a unit dosage. While 
the calcium compound can be used in any amount per unit dosage up to the 
solubility limit of the calcium compound in that system, at least 300 
milligrams, preferably at least 550 milligrams and more preferably at 
least 600 milligrams calcium is present per unit dosage of beverage. The 
calcium content can also be governed by the number of daily doses, e.g. 2 
doses. 
The invention is also based on the unexpected observation that selection of 
specific acids is necessary to avoid off taste problems with certain 
calcium compounds. Solutions of organic calcium compounds can be acidified 
with either or both organic or inorganic acids without developing off 
tastes. Solutions of inorganic calcium salts, either alone or in 
combination with organic calcium compounds, must be acidified with an 
organic acid either alone or in combination with a mineral acid. 
It has been observed that inorganic salts develop an off flavor when the 
beverage is acidified with an inorganic acid such as phosphoric acid as 
the sole acidulant. Thus, inorganic calcium salts such as the carbonate, 
oxide and hydroxide singly, in admixture or in admixture with organic 
calcium compounds such as the gluconate must be acidified with an organic 
acid. The preferred acid is citric acid used alone or in combination with 
phosphoric acid. When using a combination of acids, the ratio of organic 
acid to inorganic acid should be in an amount ranging from about 5:1 to 
about 1:5, and preferably from about 2:3 to about 3:2 on a weight basis. 
The degree of acidity is dictated by the tartness in the flavor desired. 
Since one of the popular flavors is a citrus flavor, pH's within the range 
of from about 3 to about 4 are desirable. These pH's can also be used if 
an inorganic calcium compound such as calcium hydroxide, calcium oxide or 
calcium carbonate is used as a supplement calcium source (less than 50 
percent of the total added calcium). These salts are not soluble at more 
neutral pH's. Clear beverages utilizing combinations of organic and 
inorganic calcium salts of the type mentioned above desirably have a pH 
which assists in dissolution, the point of dissolution varying depending 
on the salts added. Additional acid may be added for flavor. Since the 
calcium compounds can have a buffering effect, more acid is needed to 
obtain the desired pH than a system not so buffered. Since the taste buds 
are sensitive to both free acid and total acid, the amount of acid used to 
acidify the buffered beverage may cause an undesirable tartness. The pH is 
adjusted with this understanding in mind. 
Any food grade acid can be utilized to adjust the pH of the organic 
calcium-containing compound. For example, phosphoric acid, fumaric acid, 
citric acid, adipic and malic acid can be used without developing off 
taste. However, if the calcium gluconate is used with an inorganic salt 
such as calcium carbonate, phosphoric acid used alone develops an off 
taste. Thus, when calcium gluconate is used in combination with calcium 
carbonate, organic acids or a combination of an organic acid such as 
citric acid with an inorganic acid such as the phosphoric acid is 
required. Hydrochloric acid is less preferred as the chlorine ion can be 
nutritionally disadvantageous. The ratio of acids is such as to provide 
the desired pH level without developing an off taste. Preferably, the 
acids used for acidification are citric acid and phosphoric acid. 
Calcium carbonate when used at an acidic pH may develop some CO.sub.2 
evolution upon destruction of some of the carbonate. The calcium levels 
are generally calculations based on the starting materials so that the 
final amount of calcium is not affected. 
It has further been found that maltodextrin with a dextrose equivalent of 
from about 10 to about 20, also known as a glucose polymer, has been found 
to assist in stabilizing the calcium compounds in the acid beverages. It 
is also known that maltodextrin is an agent that assists in increasing 
calcium absorption in the body. In the preferred compositions of the 
present invention, maltodextrin is included in an amount of ranging from 
about 10 up to about 40 percent, and preferably from about 15 to about 30 
percent based on the solids content in the beverage. 
The acidic beverage of the present invention is preferably flavored and 
sweetened to improve its organoleptic acceptability. Known natural 
sweetening agents such as corn syrup solids, glucose, fructose, sucrose 
and the like, as well as artificial sweeteners such as saccharin, 
cyclamates and aspartame can be added in an amount sufficient to provide a 
sweet flavor. Natural and artificial flavors including fruit and cola 
flavors can also be added. The composition of the present invention can 
also include fruit juice or fruit juice extract, preferably without 
suspended particulates such as citrus fruits and/or cranberry juice as 
desired. Natural or artificial coloring can be added as desired. 
The beverage compositions of the invention can also include other 
ingredients normally found in soft drinks such as clouding agents, 
preservatives and the like. The provision of the clear beverage allows for 
the controlled clouding and also coloring of the beverage. The beverages 
can also contain protein for protein fortification though protein may be 
disadvantageous for calcium absorption, vitamins and minerals as well as 
agents which contribute to calcium absorption. Preferably, the additives 
do not incorporate additional particulates in the beverage. Preferably, 
fully soluble materials such as protein hydrolysates can be used. Trace 
amounts of magnesium and zinc salts may contribute to absorption. Dairy 
products such as whey protein can be added as clouding agents to simulate 
natural pulp. 
The beverages can also be carbonated to provide organoleptic 
characteristics similar to known soft drinks according to known 
techniques. 
The compositions of the present invention can also be prepared in an 
isotonic formulation to assist in the osmotic absorption of the fluid and 
the salts. These products are well known. The amount of sugar and salts 
are adjusted to provide the desired osmotic pressure. The amount of sugar 
can be decreased and the flavoring accentuated by synthetic sweeteners. 
A proposed procedure for preparing the calcium-fortified beverages of the 
invention includes the steps of mixing the calcium compounds with the 
sweetener and the maltodextrin to form a dry mix. Water is added to the 
dry mix and the ingredients dispersed. Calcium gluconate, alone or in 
combination with other calcium compounds, requires presolubilization by 
heating to 50.degree.-95.degree. C. After solubilization, the pH is 
adjusted to 3-3.5 or as desired with acidulants singly or in combination. 
Suitable flavor concentrates, preservatives and colors are added as 
desired. The volume is adjusted to the appropriate level and the beverage 
bottled and pasteurized according to good manufacturing techniques. 
The compositions of the invention can also be prepared as a syrup which can 
be later dissolved in water, carbonated water, juice and mixtures thereof, 
and bottled. The syrup preferably contains sufficient calcium and acidity 
such that only dissolution is required. Alternatively, pH adjustment, 
coloring and flavoring can be accomplished at the time of dissolution. 
The present invention is more fully illustrated in the Examples which 
follow:

EXAMPLE 1 
A calcium-containing beverage was prepared by presolubilizing 53.80 grams 
calcium gluconate in 1500 milliliters water by heating at the native pH of 
the gluconate at a temperature of about 70.degree. C. until the gluconate 
dissolved. 
Separately, 200 grams sucrose and 60 grams maltodextrin from about 10 to 
about 20 DE were dry mixed. The mixture was added and dissolved under 
stirring in the predissolved gluconate solution. 
A solution of 5.0 grams of 85 percent phosphoric acid diluted with about 5 
milliliters of water was added slowly to the 
gluconate/sucrose/maltodextrin solution under stirring. The solution was 
adjusted to pH 3.50 with citric acid-monohydrate. About 5.8 grams of 
citric acid-monohydrate was required for the pH adjustment. 
To this solution, 1.1 milliliters of Natural Lemon/Lime flavor obtained 
from T. Hasegawa USA was added. The volume of solution was adjusted to 2 
liters with water. 
The beverage was bottled in sterile bottles, pasteurized for 10 minutes at 
80.degree. C. and stored at both room temperature and at 4.degree. C. 
(refrigerator). The beverage contained 0.25 percent weight/volume calcium, 
10 percent sucrose and 3 percent maltodextrin. The beverage was and 
remains stable both at room temperature and at 4.degree. C. and did not 
develop an off taste and retained its clarity. An informal flavor panel 
found that the beverage was pleasant and palatable. 
In a separate experiment, 0.1 grams of sodium benzoate was added as a 
preservative. The use of sodium benzoate is optional and does not affect 
the flavor or solution stability of the finished beverage. 
EXAMPLE 2 
Calcium carbonate in an amount calculated to provide 0.25 percent calcium 
(W/V) in the finished beverage was dry mixed with 10 percent (W/V) 
sucrose, and 3 percent maltodextrin (10-20 DE). The dry mix dispersed well 
in 1500 milliliters water. The pH was adjusted to 3.0 with citric acid and 
phosphoric acid following the procedure in Example 1. The amount of 
phosphoric acid (85 percent) used was 17.2 grams and about 25 grams of 
citric acid-monohydrate was required for the pH adjustment. After adding 
flavor concentrates and preservatives, the volume was adjusted to 2 
liters. The product was bottled in sterile bottles, pasteurized for 10 
minutes at 80.degree. C. and stored both in the refrigerator and at room 
temperature. A storage stable clear acidic beverage with some tartness 
without off taste was obtained. The flavor panel found that the beverage 
was palatable and pleasant. 
EXAMPLE 3 
A 50/50 blend of the products of Examples 1 and 2 was prepared by 
pre-dissolving 26.90 grams of calcium gluconate in 1500 milliliters of 
water as outlined in Example 1. Calcium carbonate in an amount of 6.25 
grams was dry blended with 10 percent sucrose and 3 percent maltodextrin 
(W/V of final beverage). After dispersing the dry blend in the aqueous 
solution of calcium gluconate, the pH was adjusted to about 3.5 with a 
blend of citric acid and phosphoric acid using about 11.25 grams of 
phosphoric acid (85 percent) and about 10 grams of citric 
acid-monohydrate. The beverage was flavored, adjusted to the finished 
volume of 2 liters and pasteurized as in Example 1. After bottling as in 
the preceding Examples, a storage stable, clear, acidic beverage of good 
taste was obtained. 
EXAMPLE 4 
To a bottle (240 milliliters) containing the beverage of Example 3, dry ice 
was incrementally added until nearly saturated with CO.sub.2 and capped. 
The bottle was shaken to dissolve the dry ice in it. The carbonated 
beverage was stable and remained clear. It tasted similar to a commercial, 
carbonated soda. 
EXAMPLE 5 
A concentrated calcium-containing beverage syrup was prepared and mixed 
with carbonated water to get a carbonated, calcium-fortified acid 
beverage. The procedure is described as follows: 
0.05 gram sodium benzoate was dissolved in 150 milliliters water. To the 
solution, 26.9 grams of calcium gluconate was added and dispersed. The 
solution was heated to about 90.degree. C. to dissolve the gluconate. 
After cooling to about 30.degree. C., the solution was mixed with 100 
grams sucrose and 30 grams maltodextrin (10-20 DE). The solution was 
stirred (about 100 rpm) until sucrose and maltodextrin were completely 
dissolved. 
2.5 grams of 85 percent phosphoric acid diluted with about 2 milliliters of 
water was added slowly to the syrup containing gluconate, sucrose and 
maltodextrin. 2.8 grams of anhydrous citric acid was added slowly to the 
syrup under stirring. The resultant 250 milliliters of syrup was clear. To 
the syrup, 0.55 milliliters of Natural Lemon/Lime flavor was added. 
The syrup was cooled to about 4.degree. C. and poured slowly into 750 
milliliters of cold, carbonated water (commercial seltzer water) in a 
bottle and capped immediately. The resultant carbonated beverage was mixed 
well and stored in the refrigerator. The beverage contained 0.25 percent 
weight/volume calcium, 10 percent sucrose and 3 percent maltodextrin with 
a pH of about 3.5. 
The carbonated, calcium-fortified acid beverage was stable, clear and free 
of off taste. It was palatable and tasted like a commercial carbonated 
soda. 
EXAMPLE 6 
0.05 grams sodium benzoate was dissolved in 80 milliliters water. To the 
solution, 13.45 grams of calcium gluconate was added and dispersed. The 
solution was heated to about 90.degree. C. to dissolve the gluconate. The 
solution was cooled to about room temperature for complete dissolution of 
calcium carbonate which is added later. 
To the clear gluconate solution, 3.13 grams of calcium carbonate was 
dispersed under stirring. Care was taken to avoid lumping. A dry mix of 30 
grams maltodextrin and 100 grams sucrose was added slowly under stirring. 
5.63 grams of phosphric acid (85 percent) diluted with 3 milliliters of 
water was added incrementally to the syrup containing the calcium 
gluconate, calcium carbonate, sucrose and maltodextrin. Extensive bubbling 
was observed as the acid was added. Good stirring is essential. After the 
acid was added, the syrup was stirred until the bubbling stopped. 4.8 
grams of anhydrous citric acid was added incrementally to the syrup. After 
all the acid was added, the syrup was stirred until a clear syrup is 
obtained. The volume of the syrup was 170 milliliters. 
The syrup was cooled to about 4.degree. C. and poured slowly into 830 
milliliters of carbonated water alternately flavored with 0.62 milliliters 
of lemon/lime flavor following the procedure described in Example 5. The 
beverage contained 0.25 percent weight/volume calcium, 10 percent sucrose 
and 3 percent maltodextrin. 
The carbonated, calcium-fortified acid beverage was stable, clear and free 
of off taste. It was palatable and tasted like a commercial carbonated 
soda.