Method for fixing food ingredients on a magnesium salt substrate

A method for fixing a water-soluble water-dispersible or water-emulsifiable food ingredient is disclosed. The food ingredient is dried from an aqueous solution of a monobasic, dibasic and/or tribasic magnesium salt, the salt constituting the fixing substrate. The fixation of juice solids, flavors, colors and high fructose corn syrups are enabled by this method.

The present invention relates to a method for fixing various food 
ingredients, including colors, flavors, juice solids, vegetable solids, 
spices and hygroscopic sugars; and more specifically to fixing said 
ingredients on a magnesium salt substrate. According to the present 
invention, "fixing" or fixation refers to the entrapment and/or 
encapsulation of the food ingredient in such a manner that the food 
ingredients which are non-volatile but are subject to oxidation and/or 
moisture pickup, are protected against ambient atmospheric conditions, and 
volatile ingredients and volatile portions of ingredients are retained 
within the substrate. 
There are numerous methods in existence to fix food ingredients in edible 
substrates. Examples of materials commonly used as substrates are dextrins 
and hydrophilic colloids (e.g. gum arabic, gelatin, etc.). Use of these 
materials presented certain recognized obstacles to food fixation, 
particularly loss of flavor components resulting in a lowered "fix", and 
increase in caloric intake from use of high levels of high calorie 
substrates. 
PRIOR ART 
The prior art contains many examples of fixing food ingredients in 
substrates, and of producing dry juice solids. 
U.S. Pat. No. 3,554,768 to Feldman discloses forming a solution of a 
carbohydrate and the volatile flavorant acetaldehyde and then drying this 
solution such as by spray-drying. 
U.S. Pat. No. 3,061,444 to Rogers et al. discloses the fixation of all or a 
portion of a natural juice in a combination of water-soluble cyclic and 
acyclic dextrins by forming a solution of these materials and then drying 
the solution. 
U.S. Pat. No. 2,567,038, issued to Stevens et al. discloses a method for 
drying fruit juices that includes the following steps: buffering or partly 
neutralizing the pH of a juice with calcium carbonate or sodium citrate; 
pasteurizing the buffered juice; concentrating the juice to about 75% to 
90% solids; improving the stability of the juice by adding ascorbic acid; 
adding the concentrated juice to granular sugar and drying the product by 
a vacuum dryer or by means of an air dryer. 
U.S. Pat. No. 4,112,130, issued to Gupta reveals a method for spray-drying 
a citrus juice comprising (a) providing an aqueous slurry including up to 
about 65% solids, about 50-85% of the solids being orange juice solids 
with the balance consisting essentially of maltodextrin and (b) 
concurrently spray-drying said slurry to a powder having an average 
moisture content of less than about 4% in a spray-drying apparatus. 
U.S. Pat. No. 4,059,706 to Pischke et al. discloses the encapsulation of 
undissolved L-aspartic acid sweetening compound in a water-soluble 
encapsulating agent forming a dispersion of a water-soluble encapsulating 
agent and undissolved L-aspartic acid sweetening compound, and then drying 
this dispersion such as by spray-drying. 
DESCRIPTION OF THE INVENTION 
The present invention is directed to a process for fixing various food 
ingredients such as colors, flavors, vegetable juice solids, fruit juice 
solids, spices, hygroscopic carbohydrates (e.g., sugars, high D.E. 
dextrins, etc.), components thereof, and the like, to the products 
produced from this fixation process and to food compositions containing 
the fixed food ingredients of this invention. The present invention will 
have utility to fix any food ingredient which is either water-soluble, 
waterdispersible or water-emulsifiable. According to this invention, these 
materials are fixed in a substrate which is comprised of and preferably 
consists essentially of the magnesium salts of edible monobasic, dibasic 
and/or tribasic acids. Suitable monobasic acids are acetic acid, propionic 
acid and lactric acid. Suitable dibasic acids are adipic acid, fumaric 
acid, malic acid, succinic acid and tartaric acid. Suitable tribasic acids 
are phosphoric acid and citric acid. 
The magnesium salts display certain properties which make them suitable as 
a fixation substrate, as opposed to other salts. The use of sodium, 
potassium or calcium salts of organic or inorganic acids have not been 
found to be suitable. The magnesium salts of the above-stated acids are 
more water-soluble than the corresponding calcium salts, and 
simultaneously are not hygroscopic as are the sodium and potassium salts 
of these acids. 
In particular, an unexpected property is that the magnesium salts of adipic 
and fumaric acids are much more soluble in cold or warm water than the 
pure acids themselves. This property is most evident with fumaric acid, 
which is the least soluble of these acids. Thus, magnesium salts appear to 
be unique among the metal salts as fixatives. 
The fixation process is accomplished by mixing an aqueous solution of the 
magnesium salt and the ingredient(s) to be fixed, and then drying the 
mixture. The magnesium salt in the solution can result from the direct 
addition of a magnesium salt, or can be formed in situ by the addition of 
a basic magnesium compound (e.g. Mg(OH).sub.2 MgO, MgCO.sub.3, etc.) to an 
acid-containing solution such as a fruit juice, or by a combination of 
these two methods. The sequence in which the various materials are added 
to form a mixture of the magnesium salt solution and the food ingredient 
or ingredients to be fixed is not critical to this invention. The prime 
requisite is that immediately before drying the aqueous liquid contain 
magnesium cation, acid anion and the ingredient which is sought to be 
fixed. 
After an aqueous solution of a magnesium salt and the ingredient sought to 
be fixed is formed, the mixture must be dried. The mixture may be dried by 
any conventional drying technique such as freeze-drying, spray-drying or 
drum drying. In order to maximize efficiency of the fixation, in 
particular when those ingredients to be fixed contain or consist 
essentially of volatiles, the temperature during drying should be kept as 
low as possible. Spray-drying and freeze-drying are preferred to drum 
drying. In spray-drying the inlet air temperature is in the range of 
100.degree. C. to 250.degree. C., preferably 150.degree. C. to 180.degree. 
C., and the outlet air temperature is within the range of 50.degree. C. to 
100.degree. C., preferably 80.degree. C. to 90.degree. C. 
The amount of food ingredients which may be fixed according to the process 
of this invention can be up to 9 parts by weight for each part by weight 
of added magnesium salt. 
The amount of magnesium present should be such that, for each mole of acid 
contained in the solution, there should be from at least 0.3 moles of 
magnesium present in solution. It is speculated that the dried magnesium 
salt is the material which forms the fixation substrate, in which event 
from about 0.4 to 1.5 moles, typically about 0.5 to 0.8 moles of magnesium 
will be present in the solution for each mole of acid present in the 
solution. The level of magnesium in the dry magnesium salt substrate will 
be from about 4 to 30% by weight. 
This invention is highly suited for the fixation of natural juice 
constituents. These constituents may comprise all or part of a particular 
juice and may be of varying molecular structures. Because of the 
relatively high fix levels which can be obtained and the inherent 
low-calorie, non-carbohydrate nature of the magnesium salt substrate, the 
fixed food ingredients of this invention are ideally suited for use in or 
as low-calorie food products. Unlike prior art processes which rely on 
added carbohydrates for fixation, this process is accomplished without the 
addition of caloric carbohydrates. 
This invention has been established to provide fixation for edible solids, 
for volatile flavors and flavor enhancers such as those compounds 
naturally found in fruits, spices and vegetables, for colorants such as 
the color-imparting agents or compounds naturally found in juices or 
extracts and for hygroscopic carbohydrate solids such as those contained 
in high fructose corn syrups. As will be recognized by those skilled in 
the art, the fixation of complex mixtures such as natural juice solids 
will inherently include the fixation of flavors, colors, proteins and 
carbohydrates at one time. 
The process provides for the fixation of those ingredients which have high 
levels of solubility and/or those, such as sugars, which are known to be 
difficult to dry. This process also provides the definite and distinct 
barriers needed to retain volatile portions of ingredients within the 
substrate while also providing protection against ambient atmospheric 
conditions to the non-volatile portions of ingredients. 
The particular edible juices or extracts which may be fixed in accordance 
with this invention include those of leaves, vegetables, roots, spices, 
fruits, meat and the like. 
The following examples are provided for illustration purposes and should 
not be construed as limiting the scope of the invention.

EXAMPLE 1 
A magnesium citrate solution was prepared by combining 12.2 pounds (5.53 
kgs) of citric acid monohydrate (obtained from Pfizer, Inc., New York, New 
York) and 7.6 pounds (3.45 kgs) of magnesium hydroxide (U.S.P. obtained 
from Mallinckrodt, Inc., Paris, Kentucky) and 96.1 pounds (43.59 kgs) of 
water at ambient temperature. To this solution was added 146 pounds (66.22 
kgs) of 58.2.degree. Brix orange juice concentrate (obtained from Sunkist 
Growers, Ontario, California). Orange juice typically has a citric acid 
content of from 5 to 20%, solids basis. The mixture was then spray-dried 
using a cocurrent stream of air having an inlet temperature of 380.degree. 
F. (193.3.degree. C.) and an outlet temperature of 210.degree. F. (98.9C) 
resulting in a dry free-flowing yellow powder containing about 15% (by 
weight) added magnesium citrate carrier and about 85% juice solids. The 
dry powder was readily soluble in cold water at least up to a 10% level 
providing all the flavor characteristics of orange juice. The powder was 
also useful as an ingredient in an orange-flavored powdered soft drink mix 
at a level of from 1% to 60% by weight of the mix as a source of natural 
orange flavor, color and solids. 
EXAMPLE 2 
An aqueous magnesium hydroxide suspension was formed by combining 13.16 
pounds (5.97 kgs) of magnesium hydroxide in 76 pounds (34.47 kgs) of water 
at ambient temperature. To this suspension was added 193.75 pounds (87.88 
kgs) of 51.6.degree. Brix lemon juice concentrate (obtained from Sunkist 
Growers). This lemon juice had a citric acid content of about 60% by 
weight, solids basis. The solution was dried as in Example 1 producing a 
dry, free-flowing, bone-white powder containing about 95% juice solids and 
about 5% magnesium. The solution contained about 0.7 moles of magnesium 
for each mole of acid and the level of magnesium found in the magnesium 
salt substrate was about 8.5% by weight. The dry powder was readily 
soluble in cold water at least up to a 10% level providing all the flavor 
characteristics of lemon juice. The powder was useful as an ingredient in 
a lemon-flavored powdered soft drink mix at a level of from 1 to 70% as a 
source of natural lemon flavor, color and solids. 
EXAMPLE 3 
An aqueous magnesium citrate solution was prepared by combining 90 grams of 
magnesium citrate (Mg.sub.3 (C.sub.6 H.sub.5 O.sub.7).sub.2.2H.sub.2 O) 
obtained from B.D.H. Chemicals Ltd., Poole, England) and 900 grams of 
water. To this solution was added 840 grams of 25.degree. Brix tomato 
paste (obtained from Hunt-Wesson Foods, Inc., Fullerton, California). The 
mixture was blended to uniformity and then spray-dried using a cross-flow 
stream of air having an inlet temperature of 150.degree. C. and an outlet 
temperature of 90.degree. C. A dry, free-flowing, orange-red tomato powder 
was obtained having the natural color and flavor characteristics of 
tomato. The dry powder was readily soluble in water at least up to a 5% 
level. The dry powder was comprised of 70% tomato-solids and 30% magnesium 
citrate carrier. This powder is a suitable ingredient for use in a dry 
salad dressing mix at levels of from 5 to 25% by weight. 
EXAMPLE 4 
An aqueous magnesium fumarate solution was formed by combining 116 grams of 
fumaric acid and 42 grams of magnesium hydroxide (U.S.P. Mallinckrodt, 
Inc., Paris, KY) in 520 grams of water. To this solution was added 163 
grams of high fructose corn syrup (Isosweet 180, 80% solids, Staley 
Manufacturing Co., Decatur, IL). The mixture was blended in a Niro spray 
dryer which maintained an inlet temperature of 150.degree. C. (302.degree. 
F.) and an outlet temperature of 90.degree. C. (194.degree. F.). A dry 
free-flowing product was obtained which was readily soluble in cold water. 
The dry powder was comprised of 50% corn syrup solids and 50% magnesium 
fumarate carrier. 
EXAMPLE 5 
An aqueous magnesium citrate solution was prepared by combining 90 grams of 
magnesium citrate (Mg.sub.3 (C.sub.6 H.sub.5 O.sub.7).sub.2.2H.sub.2 O, 
B.D.H. Chemicals Ltd., Poole, England) and 600 grams of water. To this, 
415 grams of orange juice concentrate (65.degree. Brix, Caulken, FL) was 
added. 10.8 grams of orange oil (terpenless #2395, Citrus and Allied 
Essence Ltd., Floral Park, NY) were then added, and the mixture was mixed 
for 2 minutes in a Waring blender. The mixture was then atomized and dried 
in a Niro spray dryer which maintained an inlet temperature of 135.degree. 
C. and an outlet temperature of 90.degree. C. A dry, free-flowing highly 
aromatized powder was obtained. Gas chromotography revealed that the 
orange juice solids in the powder contained 3.9% orange oil. The amount of 
oil added to the solids was 3.0%, with 1.2% orange oil being naturally 
present in orange juice solids; thus, the total amount of oil present 
prior to drying was 4.2%. After exposure to ambient air for a period of 
three days, the amount of orange oil had decreased from 3.9% to 3.2%. 
EXAMPLE 6 
An aqueous magnesium citrate solution was prepared by adding 100 grams of 
magnesium citrate (Mg(C.sub.6 H.sub.6 O.sub.7).sub.2.2H.sub.2 O) to 500 
milliliters of water. To this, 3.0 milliliters of Wild Cherry flavor 
(Flavor Key, Pine Brook, NY) were added. The mixure was blended at high 
speed for 2 minutes in a flavor blender. The mixture was then transferred 
to a freeze drying pan and then fast frozen with liquid oxygen. The frozen 
slab had a nominal bed depth of 1/2". The freeze drying pan containing the 
frozen slab was then transferred to the freeze dryer (Hull Co., PA, Model 
10 F12). Once inside the dryer, the pan was placed on a shelf which had 
already been chilled to -35.degree. C. The Chamber was evacuated to 200 
microns. The shelf temperature was gradually increased from -35.degree. C. 
to 30.degree. C., over a period of 24 hours, during which time the vacuum 
did not exceed 500 microns. At the end of the 24 hour period, the vacuum 
was broken with high purity N.sub.2 gas. The freeze dried products were 
non-hygroscopic free-flowing powder. The product contained 2.2% Wild 
Cherry flavor upon drying, and after setting out in ambient air for three 
days, was found to contain 1.7% Wild Cherry flavor. 
EXAMPLE 7 
An aqueous solution of calcium citrate was prepared by combining 56.1 grams 
of calcium oxide with 210 grams of citric acid monohydrate in 532 grams of 
water. The mixture immediately gelled and later solidified rendering it 
impossible to add the acetaldehyde/diacetyl flavorant, or to spray dry the 
mixture. 
EXAMPLE 8 
An aqueous calcium citrate mixture was prepared by adding 28 grams of 
calcium oxide to 210 grams of citric acid monohydrate in 476 grams of 
distilled water. To this, 11.0 grams of acetaldehyde/diacetyl flavorant 
was added. Some of the mixture precipitated out of solution. The mixture 
was then blended at high speed in a Waring blender for approximately two 
minutes, and then transferred to a Niro dryer. The dryer was maintained 
with an inlet temperature of 120.degree. C. and an outlet temperature of 
90.degree. C. Gas chromographic analysis of the resultant powder indicates 
that there was no fixation or retention of the acetaldehyde/diacetyl 
flavorant after spray-drying. 
EXAMPLE 9 
An aqueous sodium citrate solution was prepared by adding 40.4 grams of 
sodium hydroxide pellets (99% pure) to 210 grams of citric acid 
monohydrate in 450 grams of distilled water. To this, 8.8 grams of 
acetaldehyde/diacetyl flavorant was added. The mixture was mixed in a high 
speed blender for less than 5 minutes, and was then transferred to a Niro 
dryer. The dryer maintained an inlet air temperature of 120.degree. C., 
and an outlet air temperature of 90.degree. C. The mixture did not dry, 
but remained coated on the walls of the dryer. 
EXAMPLE 10 
An aqueous solution of potassium citrate was prepared by adding 132 grams 
of potassium hydroxide (KOH, 85% pure) and 210 grams of citric acid 
monohydrate to 695 grams of distilled water. To this, 15.2 grams of 
acetaldehyde/diacetyl flavorant was added. After mixing, the mixture was 
transferred to a Niro spray dryer, which maintained an inlet air 
temperature of 120.degree. C. and an outlet air temperature of 90.degree. 
C. The resultant free-flowing powder was hygroscopic and collapsed in 
storage over night.