Wellness Foods Europe THE MAGAZINE FOR NUTRITIONAL AND FUNCTIONAL FOODS & BEVERAGES HealthyChoices@Jungbunzlauer Mineral fortification in dairy Reprint from Wellness Foods Europe issue 1/2013 Wellness Foods Europe Minerals Mineral fortification in dairy Markus Gerhart and Martin Schottenheimer Introduction > The global functional foods be healthy and fortification makes them even market is dominated by dairy products, with healthier. They are a popular part of the diet sales valued at 9.23 bn USD in 2010 [1]. De- and their consumption is a daily routine. This spite already being a well-developed market favours their usage as a carrier for functio- in many countries, manufacturers are con- nal foods that should be consumed regular- tinuing to innovate, driven by the consumers ly. Milk products are already a good source demand for products that fit into their diet of calcium and fortification leads to products and nutritional needs. In consequence, the that can contribute more than 50 % of the scope for the growth of new, innovative, and daily requirements to the diet. healthier products is steadily increasing [2, Functional dairy products have been 3]. This success is based on various pillars. impac ted in the EU by the recent health In general, dairy products are perceived to claims regulation, as the usage of claims on Minerals Wellness Foods Europe popular functional ingredients like pro- or tions are dissolved in the aqueous phase [6]. prebiotics is restricted. However, there is still Mineral supplementation of milk is challeng- room in the market for new products [3]. Es- ing, because the soluble phase is considered pecially minerals like calcium, magnesium or to be saturated at its normal pH, making fur- zinc can offer a wide range of claim options ther addition difficult [7]. that address the top health topics like bone Therefore, selection of the appropriate health, immunity, energy or cognitive func- mineral source for a specific application is tions. These health benefits can be clearly de- extremely important. Commonly used calci- fined and are easy for the consumer to under- um, magnesium and zinc salts in dairy appli- stand. Recent examples like “Yoplait Calin+” cations are shown in table 1. or “Danone Densia” underline what is still Properties of the respective mineral com- possible in the market. Containing 50 % pounds such as mineral content¸ solubility RDA of calcium per serving plus vitamin D and taste are essential parameters for pro- and referring to bone health, these products duct development while bioavailability and set a new benchmark for calcium fortified economic considerations are also of high im- yoghurts. portance. However, feasibility of mineral addition Suitable mineral salts can roughly be sub- has to be considered, as milk products are a divided into soluble or insoluble minerals. complex food matrix and high fortification When using soluble salts, sedimentation and levels are challenging. With the right selec- influence on mouth feeling are negligible tion of the appropriate mineral compound at first sight, while impact on taste and pH and the proper application success is possible. value is increasing with rising fortification Based on our history and expertise on levels. However, pH changes and the addi- mine ral fortification, Jungbunzlauer has re- tional free ions can destabilise the system cently started a cooperation with the Univer- especially du ring heat treatment. This may sity of Hohenheim in Germany to fully un- lead to coagu lation, syneresis and reactions derstand the applicability of mineral salts in with further ingredients of the milk product dairy products [4]. like phosphate and proteins [8]. Addition of This article discusses important nutritional chela ting agents such as potassium citrate and technological aspects of mineral fortifica- has been shown to enable higher fortification tion of dairy products. It provides the major levels by adjusting the pH level, chelating free findings of our internal lab work and our co- cations as well as competing with calcium to operation with the University of Hohen heim reduce cross-linking [7]. with specific focus on calcium, magnesium In contrast to soluble minerals, low or and zinc fortification in milk, yoghurt as well insoluble minerals remain mainly dispersed as drinking yoghurt. within the product, thereby having much lower impact here on the dairy matrix. In Challenges > Milk is an important source of addition, their influence on taste is less pro- minerals in our diet and about 40% to 74% of nounced, as bitter and astringent off-tastes daily calcium is provided by dairy foods [5]. are related to free ions of dissociated minerals. Together with magnesium, potassium and so- While being mainly suspended, insoluble dium, calcium plays an important role in the minerals can affect mouth feeling in terms structure and stability of casein micelles. In of grittiness and chalkiness, and can lead to whole milk, about two thirds of its calcium sedimentation in low viscous products. Mi- and one third of its magnesium is bound in cronised mineral salts are a good option to the micelle and the remaining mineral frac- address these undesired effects. Speed of sed- Wellness Foods Europe Minerals Table 1. Overview of calcium, magnesium and zinc salts approved for fortification in Europe acc. to Regu lation (EC) No. 1825/2006 Compound Mineral Content Solubility Taste Calcium Carbonate 40 % Insoluble Soapy, lemony Calcium Chloride · 2 H2O 27 % 745 g/l Salty, bitter Calcium Lactate · 5 H2O 14 % 90 g/l Bitter at high concentrations Calcium Lactate Gluconate 13 % 400 g/l Slightly bitter at high conc. Ca (as Calcium Lactate & Calcium Gluconate) Tricalcium Citrate · 4 H2O 21 % 1 g/l Tart, clean Tricalcium Phosphate 40 % Insoluble Sandy, bland Magnesium Carbonate basic · 5 H2O 24 % 4 g/l Earthy Magnesium Lactate · 2 H2O 10 % 70 g/l Neutral Magnesium Sulfate · 7 H2O 10 % 710 g/l Saline, bitter Mg Trimagnesium Citrate · 9 H2O 12 % 16 g/l Neutral Trimagnesium Citrate anhydrous 16 % 200 g/l Neutral Trimagnesium Phosphate · 5 H2O 21 % Insoluble Neutral Zinc Citrate · 3 H2O 31 % 3 g/l Slightly bitter Zn Zinc Gluconate · x H2O 13 % 100 g/l Bitter, astringent Zinc Oxide 80 % Insoluble Bitter Zinc Sulfate · 7 H2O 23 % 960 g/l Astringent, bitter, metallic Source: Internal evaluation and [7]; Jungbunzlauer products are marked in bold imentation is reduced by decreasing particle Fortification of milk > When fortifying milk, size and ultrafine particles are no longer per- solubility, dissolution characteristics, sedi- ceived. Particles significantly smaller than mentation behaviours and stability of the final 20 µm allow fortification levels far above the formulation are major challenges. Organic ones achievable with dissolved minerals. calcium salts like calcium gluconate, calcium lactate, or calcium lactate gluconate and in- Bioavailability > Any nutrient’s effectiveness organic calcium chloride are highly soluble, depends on its bioavailability, meaning how but their use is limited due to off tastes at well the human body absorbs and utilises it. higher concentrations. Having the lowest Mineral bioavailability from food sources taste impact within the range of soluble cal- can vary from e. g. 10–30% for calcium, 40– cium salts, calcium lactate gluconate can be 60 % for magnesium or 5–50 % for Zinc [7]. added to achieve 200 mg of total calcium Several scientific studies indicate that organic to 100 ml milk without a significant influ- mineral salts like citrates, lactates or gluco- ence on its taste. Due to their influence on nates outperform inorganic mineral sources pH value and the contribution of free calci- such as oxides, carbonates and phosphate um ions, products tend to be unstable during with regard to their relative bioavailability heat treatment. However, with the addition [9, 10]. of tripotassium citrate the system can be sta- Minerals Wellness Foods Europe bilised, but the effect is limited to lower for- Sedimentation behaviour can be further im- tification levels. As a new route, addition of proved, by increasing the viscosity of the sterilised or ultrafiltrated mineral solutions milk. In our trials, the addition of kappa car- after the heat treatment step is a recommen- rageenan has shown the most promising re- ded alternative and results in stable fortified sults. At above mentioned fortification levels UHT milk (Figure 1). sedimentation can still appear, but ultra- Inorganic calcium carbonate and calcium fine tricalcium citrate typically shows good phosphate are insoluble. The organic tricalci- re-dispersability compared to other calcium um citrate in the commonly used tetra hydrate forms. form shows a slight solubility of 1 g/l while In contrast to calcium, magnesium for- having low effect on product pH value and tified milk products are less common and thus minor effect on product stability, even available literature is limited. Being also a when applied at higher concentrations. Tri- bivalent cation, the addition of magnesi- calcium citrate shows an “inverse solubility”, um salts has shown similar behaviour as in i. e. it is more soluble at lower and less soluble case of calcium according to our experience. at higher temperatures. The latter is beneficial Vari ous liquid milk products contain readily during heat treatment, as the risk of coagula- soluble magnesium salts like organic trimag- tion can be further reduced (Figure 1). nesium citrate anhydrous or magnesium lac- tate and inorganic magnesium sulfate. They also destabilise the milk matrix during heat treatment. In this respect, tripotassium cit- rate improves heat stability and enables a for- tification to 210 mg magnesium per 250 ml serving (55 % EU RDA). Addition of trimag- nesium citrate anhydrous after heat treat- ment allows similar or even higher magnesi- um contents, without need for stabilising via tripotassium citrate. Surprisingly, the forti- fication showed positive effects on the taste profile of milk. In contrast, addition of mag- nesium sulfate had a negative taste impact. Insoluble magnesium salts like inorga- nic magnesium carbonate and magnesium Fig.