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Delicious and Refreshing Beverages Fortified With Specialty Minerals Calcium Carbonates

Beverages fortified with calcium account for a significant part of the growing functional beverage market, as consumers become increasingly aware that calcium is a necessary ingredient for good nutrition and bone health. Osteoporosis, a disease characterized by skeletal deterioration, is directly linked to calcium deficiency.

The aim of the calcium-fortified beverage manufacturer is to provide a reasonable percentage of the Recommended Daily Intake (RDI) or Recommended Daily Allowance (RDA) for calcium in each serving. The extent of a person’s daily need for calcium depends on age and health status. The U.S government recommends that adults consume 1,000 milligrams of elemental calcium each day. Similar schedules are issued by the health authorities in most countries, and tend to recommend calcium amounts in the same ranges as those adopted in the U.S.

Why Fortify With A Specialty Minerals Precipitated Calcium Carbonate (PCC)?
First, why calcium carbonate? Calcium carbonate continues to increase its share of usage in calcium-fortified opaque beverages. It is a highly bioavailable form of calcium—among the best—and is absorbed as well as the natural calcium in cow’s milk. Calcium carbonate is also the most economical in use, as it combines a high level of elemental calcium (40 percent), thus reducing the weight of fortificant needed to reach the desired calcium level, in turn offering one of the lowest costs among calcium sources used in beverages. It only takes one-quarter gram of calcium carbonate to provide 100 millgrams of elemental calcium, or 10 percent of an adult’s daily requirement.

Second, why a Specialty Minerals Inc. (SMI) precipitated calcium carbonate (PCC)? SMI manufactures several small and nano particle-sized PCCs that provide excellent, smooth taste plus superior suspension and reduced settling. These are ViCALity Albafil® and CalEssence® 70 PCCs, which are 0.7 micron in particle size, and the nano particle products, Multifex-MM® USP and Calofort® U PCCs, which are only 70 nanometers, or 0.07 micron, in size. Food-grade ground calcium carbonates (GCCs) are all larger, typically 4 to 10 microns or more, and are not suitable for these beverage applications because they settle out quickly and give a sense of grittiness and off-taste.

Calcium Carbonate Suspension In Beverages: Particle Size Effect
To produce a calcium-fortified beverage wherein calcium will remain in suspension in the refrigerator or on the shelf, manufacturers must consider two factors: particle size and stabilizer use. Keeping the calcium carbonate in suspension is important, for if it settles, a layer forms at the bottom of the container; this settled calcium is unattractive in a transparent bottle, and if not redispersed, causes the consumer to lose part of the fortification value of the drink. Solids which come out of suspension also can result in a chalky taste if the person who consumes the last part of the beverage winds up with a mouthful of solids.

As for particle size: According to Stokes Law, the velocity with which an individual particle moves downward through a liquid (settles) follows this formula:

 

For a given system, all the parameters except particle size will be constant, and can be set equal to K, yielding a simple formula:

                                         Velocity = (radius)2 K

The rate of settling of an individual calcium carbonate particle in a beverage is proportional to the square of the radius of the particle. If the particle size is doubled, the rate of settling of that particle should increase by a factor of four. If the particle radius is decreased by a factor of 10, the rate of settling of that particle should decrease by a factor of 100. 


Reduced Settling Of Small Precipitated Calcium Carbonates (PCCs)
Slurries were made of PCCs ranging in size from 0.7 microns (ViCALity Albafil® PCC) to 12 microns (ViCALity® Ultra Heavy PCC); they were then allowed to stand, and the amount of settling was measured. As can be seen on the graph, the amount of settling decreased dramatically as the particle size was decreased.

 

Choosing the smallest particle-sized calcium carbonate that fits the formula’s economic constraints will provide the greatest suspension properties in the beverage. Using a smaller PCC may also allow a reduction in the amount of stabilizer needed, which can reduce costs.


Calcium Carbonate Suspension in Beverages: Use of Stabilizers
Simply including a small-sized calcium carbonate in a fluid is insufficient to make a stable product that does not settle. It is also necessary to use a stabilizer, usually a natural gum, that will increase the viscosity of the mixture. In Stoke’s Law, above, the denominator is the viscosity of the liquid. Increase the viscosity and the rate of settling will decrease.

For liquids thickened with cellulosics, carrageenans, and other stabilizers, the thickness you feel or the viscosity you measure depends on how much force is being applied to the liquid. Increase the amount of force or work applied and the viscosity decreases proportionally. The liquid is said to be shear thinning or has pseudoplastic flow.

 

In beverages, the viscosity that controls the settling of the calcium carbonate is not the package viscosity—that is, the thickness you feel when you stir the liquid. It is the viscosity of the liquid when only the force of gravity is being applied (a very small force). The advantage of using thickeners with shear-thinning rheology is that the package viscosity can be very low—such that the beverage appears or “feels” thin—but the low shear viscosity that keeps the particles in suspension when the beverage is just standing is very high.

Though many kinds of stabilizers can be used in calcium fortifying milk, soy milk, drinkable yogurt, and other beverages, we find that iota carrageenan is best. It provides excellent suspension control at low usage levels. We recommend these stabilizers for use with calcium carbonate:

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Adding calcium carbonate to your formulation may not require additional stabilizer. Most flavored milks and soymilks already contain a stabilizer to suspend the color, flavor, or soy protein, and that may be enough to suspend the calcium carbonate as well. Replacing a larger calcium carbonate with a small or nano PCC may also allow less stabilizer to be used to achieve equivalent suspension, or may improve the suspension with the current level of stabilizer.


Calcium Fortified Beverages
The range of tasty and healthy drinks that are being calcium fortified continues to grow, as products increasingly are targeted to different consumer sectors. Among them:

  • Cow’s milk – from whole to non-fat, fresh pasteurized or UHT (ultra high temperature) processed shelf stable, plain or flavored. Chocolate is a special favorite. Milk from other animals can also be calcium fortified.

  • Soymilk – long a standard in Asia, but growing in popularity in the U.S and in Europe. As with cow’s milk, comes either refrigerated or aseptically packed shelf stable, natural or flavored. Vanilla is a popular soymilk flavor in the U.S.

  • Drinkable yogurts and yogurt smoothies – an increasingly popular form of this food, fortified for bone health.

  • Probiotics – newest of the types of fortified beverages, into which additional beneficial bacteria are added for intestinal health.

  • Liquid Meal Replacements and Supplements – complete nutrition in a can or bottle, for occasional use in place of a meal or to add extra nutrition to a meal. Dietetic forms are useful for weight loss.

  • Infant Formulas – either milk- or soy-based for babies.

  • Powdered Drink Mixes – some mixes provide the complete ingredients for the protein, energy, meal replacement, diet shake or other beverage; others provide the flavorings and nutritional ingredients to be added to milk or other existing beverage.

Where Not To Use Calcium Carbonate In Beverages and Liquids
Note that calcium carbonate is not suitable for clear beverages, as it is not water soluble. It is excellent in milk, soy milk, infant formula, and similar beverages, as they are already opaque. Calcium carbonate is also not suitable for fruit beverages and juices, which have an acid pH, because the calcium carbonate will react with the fruit acid to liberate carbon dioxide gas. One of the more expensive—but water soluble—calcium salts should be used.

Milks Fortified With Specialty Minerals Precipitated Calcium Carbonates (PCCs)

Most of us don’t get nearly enough calcium in our diets. Milk, of course, is one of the best sources of natural calcium, but in North America and many parts of Europe, milk consumption had steadily dropped, even among children. In other parts of the world, especially Asia, milk was never part of the traditional diet to begin with. Fortunately, this is beginning to change, as governments and medical organizations worldwide institute osteoporosis-awareness programs, as well as school milk programs, where every child gets milk each school day.


Calcium Fortified Milk
This begs the question: But why fortify milk? After all, doesn’t it already contain plenty of calcium?

Yes, it does. Typical cow’s milk contains 300 milligrams of elemental calcium in an eight-ounce/250 milliliter glass, or 120 mg per 100 ml. The U.S. government recommends that adults get 1,000 mg of calcium each day, and that teenagers get 1,200 to 1,500 mg. If adults drank three glasses of milk each day, and teenagers five, they would get most of the calcium their bodies need. Trouble is, that seldom happens, even in countries with long histories of milk drinking.

The food industry is providing two pathways to increased calcium consumption: getting people to want to drink more milk, and putting more calcium in the milk they do drink.

Milk producers encourage people to drink more milk by making it more appealing to drink. Chocolate, strawberry, vanilla, and other flavored milks are especially popular with children. They can be bought refrigerated, in small bottles ready to drink, or as powdered mixes, which are added to plain milk or to water. It’s a good way to get an extra serving of milk into a child (as well as an adult with a sweet tooth).

As for the second approach, many countries are already using high-calcium milks in which the calcium level has been raised as much as 40 percent—from the base level of 120 mg/100 ml to 165 mg/100 ml, or about 415 mg of calcium per eight-ounce glass. These milks can be plain or flavored, and either pasteurized and refrigerated or in ultra high temperature (UHT) shelf-stable packages. Some of the popular milk-flavoring mixes add extra calcium to the dry mix itself. Dry powdered milk, either whole or non-fat, also can be calcium fortified, an especially useful tactic in areas of the world where refrigeration is uncommon.

These approaches can apply not only to cow’s milk, the form most commonly consumed, but to the milks of goats, sheep, camels, and other animals as well.

Fortifying Milk With Calcium Carbonate
Calcium carbonate is frequently chosen as the fortificant in liquid milks and flavored powdered milk drinks and mixes. Calcium from calcium carbonate offers high bioavailability—it is absorbed by the body as well as the calcium in the milk itself. Because of its high elemental calcium level of 40 percent, only small amounts are needed to add the extra fortification. Just ¼-gram of calcium carbonate provides 100 mg of elemental calcium. This, coupled with its being one of the least expensive forms of calcium used in foods, makes calcium carbonate an extremely cost-effective choice.

Unlike soluble forms of calcium, calcium carbonate interacts only weakly with milk proteins. Milk also has natural buffers, so there is little change in pH when calcium carbonate is added.

Fortifying Milk With Specialty Minerals Precipitated Calcium Carbonates (PCCs)

Consumers, especially children, will not drink what tastes (or looks) bad. Accordingly, the choice of calcium carbonate to be used in fortification has a make-or-break effect on whether consumers accept the resulting drink. In liquid milks, a small particle-size, solid precipitated calcium carbonate (PCC) should be used; this will leave the milk’s smooth, delicious taste unaffected, and ensure that the added calcium stays in suspension rather than settling out to the bottom of the container.

SMI’s ViCALity Albafil® and CalEssence® 70 PCCs are USP/FCC products that are only 0.7 microns in size. Particles this small offer far less sedimentation than the ground calcium carbonates (GCCs) of 4 to 10 microns or larger often used in solid foods. These PCC grades are made by SMI in Adams, Massachusetts. They are suitable for milk products that must comply with the Proposition 65 lead limits in California, with the ViCALity® PCC having less than 500 ppb (parts per billion) lead and the CalEssence® PCC having less than 125 ppb.

Even better suspension comes from using a true nano PCC, the 70 nanometer, 0.07 micron Multifex-MM® USP PCC or Calofort® U EP PCC. These products are manufactured in SMI’s plant in Birmingham, U.K. They are harder to disperse than the 0.7 micron products and require higher shear mixing, but once dispersed, they will stay in suspension better and longer. While their lead levels meet the requirements of the U.S. Pharmacopeia, they will likely not be usable in products concerned with California Proposition 65.

For powdered milk and milk flavor mixes, a slightly larger particle, but one with an open structure, is a viable alternative. ViCALity® Extra Light PCC is a scalenohedral PCC with a “starburst”-type structure. 

 

ViCALity® Extra Light PCC is excellent in powdered mixes as it disperses easily while also helping to separate the particles of other ingredients and facilitate their own dispersal in the liquid. The ultra-low lead version is CalEssence® 160 PCC. This type of product is also manufactured by SMI in Birmingham, U.K. as Calopake® Extra Light PCC, a EP, BP and E170i-compliant product. All of the SMI’s healthcare PCCs are also certified as Kosher.

Interactions of Precipitated Calcium Carbonate (PCC) with Proteins in the Calcium Fortification of Dairy and Non-Dairy Beverages

Calcium fortification of foods and beverages is important to prevent osteoporosis and improve general bone health. This can be challenging because the calcium ion interacts strongly with food components such as proteins. Most previous studies of calcium-protein interactions have utilized soluble calcium sources. Little work is reported on insoluble calcium sources such as calcium carbonate.


Study of Precipitated Calcium Carbonate (PCC) Interactions with Proteins
The Specialty Minerals Inc. (SMI) Healthcare Laboratory studied the interaction of precipitated calcium carbonate (PCC) with proteins used in dairy and non-dairy beverages, including non-fat dry milk, fresh milk, casein, whey, soymilk, and soy protein isolate. Researchers analyzed suspensions of each protein with and without added PCC for changes in pH, viscosity, settling stability and temperature stability, and for the effects of regular and ultra-high-temperature (UHT) pasteurization. The results were presented at a Poster Session of the 2002 Institute of Food Technologists Annual Meeting. 

The conclusions:

  • Because PCC interacts weakly with dairy and non-dairy proteins, calcium fortification should not be difficult.

  • PCC causes a slight rise in pH, most noticeably with soy. The pH can be buffered back.

  • Whole milk pH changes little, as it contains natural buffers.

  • Milk proteins alone—whey and calcium caseinate—buffer pH less than does whole milk.

  • Viscosity is not significantly affected by the addition of PCC, and shows minimal changes over time.

  • When PCC is added, a stabilizer is needed to help keep the calcium carbonate in suspension.

  • Whey protein coagulates at about 70° C / 158° F, and the coagulation is accelerated by calcium chloride, CaCl2. It takes 10 to 20 times as much calcium carbonate to give the same acceleration as the calcium chloride. The whey protein is more tolerant of calcium carbonate than of calcium chloride.

Specialty Minerals Precipitated Calcium Carbonates (PCCs) For Beverage Fortification
The SMI PCC used in this study was ViCALity Albafil® PCC, a 0.7 micron prismatic particle. ViCALity Albafil® PCC is the prime recommendation for fortification of beverages and other liquids because of its small particle size, which maximizes suspension and minimizes taste and mouth-feel effects. It is a low-lead PCC, containing less than 500 ppb (parts per billion) lead, so it can be used for many beverage applications which are required to meet California Proposition 65 lead limits.

In a situation that requires even lower levels of lead, but a high level of calcium fortification, there is an ultra-low-lead version of ViCALity Albafil® PCC, called CalEssence® 70 PCC. Both products are made in the SMI plant in Adams, Massachusetts, meet USP and FCC requirements for calcium carbonate, and are certified as Kosher.

Even greater degrees of suspension, with lower settling, can be achieved with nano PCCs. SMI’s nano PCCs, Calofort® U and Multifex-MM® USP PCCs, are true nano particles—only 70 nanometers, or 0.07 micron, in size. They are manufactured in the SMI plant in Birmingham, U.K and are sold as Multifex-MM® PCC in the U.S. and the Asia-Pacific area, and as Calofort® U PCC in Europe and the rest of the world. Multifex-MM® USP PCC is certified as meeting USP and FCC for calcium carbonate, and Calofort® U PCC is certified as meeting EP and BP, as well as E170i Miscellaneous Food Regulations. Both are certified as Kosher.

Lead Levels in Specialty Minerals Calcium Carbonates

California Proposition 65
The levels of lead in precipitated and ground calcium carbonate must be considered by every manufacturer who sells calcium nutritional supplements, calcium-containing multi-vitamin/multi-mineral tablets, calcium-based antacids, and calcium-fortified foods.

California Proposition 65 limits exposure of its citizens to lead. You can click on the link in the Learn More list below to read about California Proposition 65 lead limits.


Specialty Minerals Calcium Carbonate For Proposition 65 Uses
Food, nutritional, and antacid manufacturers who must comply with this law can turn to Specialty Minerals Inc. (SMI), which manufactures Proposition 65-compliant precipitated calcium carbonates (PCCs) and a ground calcium carbonate (GCC) in its U.S. plants.

The CalEssence® PCC family, the ViCALity® PCC family, and ViCALity® GF GCC contain low or ultra-low levels of lead. Details on lead levels in these products are on downloadable information sheet. Click on the following link for this sheet:

Lead Levels in Specialty Minerals Calcium Carbonates

Details on the test methods, statistical studies, and lead levels are described in this information sheet.