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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. Click here for a complete list of U.S. RDIs for calcium. 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:

S-PMFF-20-TB-1.gif


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.

Click on one of the product types to read more about making them calcium fortified with a SMI PCC.


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.

 

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