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Healthy and Good Tasting Calcium Fortified Soymilks Using Specialty Minerals Precipitated Calcium Carbonates

Soymilks and other soy-based products have long been part of the Asian diet. Consumption of these products in North America and Europe had been limited mainly to vegans, vegetarians, and those who are lactose intolerant.

Lately, however, the health benefits of soy and soy isoflavones has led to their increased use by general populations worldwide. The manufacture of such products are no longer confined to local producers and are now embraced by large multinational corporations. Formulations tailored to local tastes and supported by major advertising campaigns have resulted in greater consumer awareness and large growth in soymilk sales. 

Today’s soymilks come in myriad flavors including vanilla, berry, and chocolate.  Of course, soymilk also comes in the natural, unflavored variety. The amount of “beaniness” is adjusted for local or group preferences; some consumers prefer a strong soy flavor, others do not. Soymilks are available as pasteurized refrigerated products or in UHT (ultra- high-temperature processed), aseptic, shelf-stable packages. 

Plant-based milks are made not only from soybeans but also from rice, oats, red beans, wheat, and other cereals or beans.


Calcium Fortified Soymilks
One shortcoming of soymilks and other plant-based milks is their low level of natural calcium. Soymilk typically contains 10 milligrams of elemental calcium per 100 milliliters which is far less than the 120 mg/100 ml in cow’s milk. With the increased concern about osteoporosis, adding calcium to soymilk has become common. Less than 1/3 gram of calcium carbonate added to soymilk will bring its calcium content up to that of cow’s milk.


Soymilks Fortified with Calcium Carbonate
Calcium carbonate is 40 percent elemental calcium—among the highest levels of the calcium compounds used for fortification—which means that a small amount will deliver the desired level of calcium fortification. Calcium carbonate is also one of the least expensive calcium fortificants. The small amount needed plus lower price yields excellent user economics.
Water-soluble calcium compounds, such as calcium chloride, are known to interact strongly with soymilk and soy protein, as well as with proteins in animal milks. This can lead to coagulation problems, especially during pasteurization and UHT processing.

Water-insoluble calcium carbonate interacts only weakly with these proteins, hence there is no degradation of the soluble soy proteins when using calcium carbonate. It will raise the pH of the soymilk a bit, but the pH can be restored to the original level with a phosphate buffer. Click here to read more about Specialty Minerals Inc.’s (SMI’s) Healthcare Laboratory study on the interaction of calcium carbonate with cow’s milk, milk proteins, soymilk, and soy protein isolate.


Fortifying Soymilks with Specialty Minerals Precipitated Calcium Carbonates
The best form of calcium to use in fortifying soymilk is SMI’s precipitated calcium carbonate (PCC). In addition to the benefits offered by all calcium carbonates, SMI PCCs come in very small and nano sizes, which yields soymilks with excellent taste, mouth feel, and suspension of the fortifier.

SMI’s small-sized PCCs measure 0.7 microns, while the nano PCCs are one-tenth that size, or 0.07 microns. The smaller the particle, the less its effect on taste, and the better the suspension of the calcium carbonate in the soymilk. Click here to read about the fundamentals of suspension of calcium carbonate in liquid food products, the role of particle size, and the kind of stabilizers recommended. Using a larger-particled, food-grade ground calcium carbonate (GCC), which typically ranges in size from 4 to 10 microns or more, yields less satisfying results because GCCs settle out faster and leave a gritty, chalky taste from the soymilk.

SMI’s 0.7 micron products are ViCALity Albafil® PCC and CalEssence® 70 PCC. Both are manufactured in Adams, Massachusetts, meet the USP and FCC calcium carbonate requirements, and are certified Kosher. They differ in lead levels, with the ViCALity® PCC family with less than 500 ppb (parts per billion) lead and the CalEssence® PCC family, ultra-low lead level products, with less than 125 ppb lead. These lead levels are important to manufacturers of products sold in California because of the lead limits of Proposition 65 that must be observed.

SMI’s nano PCC for foods, 70 nanometers or 0.07 micron in size, is sold as Multifex-MM® USP PCC in North America and the Far East and as Calofort® U EP PCC in the rest of the world. Both are manufactured by SMI in Birmingham, U.K., certified as USP or EP, meet the U.S. Food Chemicals Codex or EU E170i regulations, and are Kosher. They are not recommended for California Proposition 65–compliant product use, even though they meet U.S. Pharmacopeia lead requirements.

Dried soymilk can also be calcium fortified using a SMI PCC. We recommend either the small PCCs used in liquid soymilk or a slightly larger, scalenohedral PCC. Scalenohedral PCC has an open, starburst-like structure which helps keep the dry soymilk particles apart and enables them to disperse quickly and evenly when added to water. The SMI scalenohedral products recommended are ViCALity® Extra Light, CalEssence® 160, and Calopake® Extra Light EP PCC. The latter product is manufactured in the U.K.

A calcium fortified soymilk was developed and used during an Institute of Food Technologists Exhibition. Reactions to its smooth, creamy taste and texture were excellent. Click here for that formulation.


Precipitated Calcium Carbonate vs. Tricalcium Phosphate (TCP) in Soymilk
Calcium phosphates, particularly tricalcium phosphate (TCP), often have been used to calcium fortify soy milks. An SMI PCC is a better choice. Even the smallest tricalcium phosphate is a much larger particle than SMI’s small and nano PCCs, settling out more quickly and to a greater extent than PCC. Significantly higher levels of stabilizing thickeners are needed to control TCP settling.

PCC produces a soy milk that is whiter (that is, less yellow). There is no difference in the amount of interaction of PCC and TCP with the soy proteins and neither causes any degradation of the soluble proteins. Click here to read more about the comparison of PCC and TCP in soy milk and click here to read more about the milk and soy protein interaction studies carried out by the SMI Healthcare Laboratory.

Some believe that TCP enjoys an advantage in its ability to provide phosphorus content. However, the diets of most people—especially those who regularly consume colas and other carbonated soft drinks—already contain far more phosphorus than the body requires.

Finally, PCC is more economical to use.

 

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