Dietary minerals function to regulate enzyme and hormone production, control blood sugar levels, and balance and improve absorption of other minerals, such as calcium. Minerals participate in some manner in virtually every cellular action in the body.
Minerals are commonly added to multivitamin blends and used to fortify a variety of cereals, beverages, baked goods, and nutrition bars.
In spite of decades of misinformation on sodium and health, sodium-chloride—salt—actually is a mineral compound vital to health. In the body, sodium and chloride from salt are key players in nerve conduction and cellular communication. Very simply put, a truly salt-free diet would swiftly be fatal.
Minerals 101
Minerals come in multiple chemical forms, and some, such as the amino acid chelators, are more bioavailable in the body than others. Minerals have different solubilities and bioavailability in humans; come in different particle sizes (such as fine and coarse or even nanostructured); and, of course, have different price ranges. Some even have different tastes that are more appealing than others.
In food processing, mineral ions also can be used to assist in the gelation process. For example, calcium ions can be used to form gels with alginate or low-methoxyl pectin in dairy products. Gelation of low-acyl gellan gum is promoted by either calcium, magnesium, sodium, or potassium ions.
The selection of the type of mineral compound used to fortify a food product will depend on the end-use application and the desired label claim. Depending on the bioavailability of the compound used in the fortified food, the consumer could take up more or less of the desired mineral, thus the amount of the mineral on the label does not always correspond with the mineral absorbed.
This is especially true for iron. Highly bioavailable iron compounds can cause drastic color and taste changes in foods and often are substituted for less bioavailable compounds that cause fewer problems. Newer ingredient technology, however, has pushed that limit and allowed higher bioavailable iron compounds to be used in formulations.
Microencapsulation
Several factors can impact the stability of nutrients. These include heat, light, moisture (relative humidity), oxygen, and pH. Microencapsulation is a process of covering the surface of an ingredient (core) with a coating material. There are different processes and methods used to encapsulate and protect nutrients, depending on the stability of the nutrient, usage level, and end-use application.
The coating materials used to form the outer shell typically are film-forming, pliable, tasteless, and non-hygroscopic and can be different fats or waxes with varying melting points. Examples include paraffin wax, which has a lower melting point of 55°C, up to carnauba wax and fully hydrogenated castor oil, which have much higher melting points between 84-88°C.
Encapsulation provides seeral functional benefits, such as prevention of premature ingredient interactions, decreased processing problems, extended shelf life, and taste and odor masking of nutrients. Methods to release the core ingredient include heat, moisture, chewing, and mechanical agitation. Since coating can affect the bioavailability of minerals, care needs to be used to adjust the level of fortification to ensure adequate absorption.
In order to account for any manufacturing and/or stability losses, overages are used when warranted. While typical overages used for some nutrients are between 10-30%, some nutrients can require overages to go as high as 100%. However, minerals are more stable against degradation and usually only require overages between 5-10%.
In using overages, managing different forms of a specific mineral also is necessary. For example, a much higher amount of zinc gluconate-hydrate would need to be added to a product to obtain the same zinc level as using zinc oxide. This is because the elemental zinc content of the gluconate form is only present at about 13%, while for the oxide form, it is about 80%. However, there is a trade-off. The zinc gluconate is far more soluble and, thus, bioavailable as compared with the oxide form and would work far better in a beverage application.
Using fats and waxes to coat particles is known as “hot-melt” encapsulation. Typically derived from soybean, palm, fractionated palm, or cottonseed oils, they have melting points higher than body temperature and can require a thicker shell to coat particles, as the fats are softer and subject to some attrition during processing or mixing.
Product formulators should be aware that using an encapsulation means there is less room in the final formulation for other ingredients. Another point to consider is that various forms of a nutrient also affect the actual quantity of the elemental mineral that will be used to meet a label claim.
New Distribution
New formats for delivering mineral fortification have been a boon to the industry. Of these, chewable gummy candies rank among the most popular. However, the manufacturing of gummy vitamin products requires a more specialized encapsulation process, since the nutrients are subjected to high heat, moisture, and acidity levels. For these products, ethylcellulose often will be used as the shell coating.
Using ethylcellulose involves a solvent-based process, however. This means it is more expensive and slower as compared with hot melt encapsulation. The advantage is that the melting point of an ethylcellulose shell is much higher than a fat/wax coating, providing greater protection for the sensitive nutrients within.
Trituration is another method of protecting and distributing trace minerals. With trituration, chemical compounds are sprayed onto an inert carrier, such as maltodextrin at a low level of 1.0%, so that they can be homogeneously distributed into the powder substrate. These value-added products then can be added into a vitamin-mineral premix for a variety of food or beverage applications. This method especially can be helpful with trace elements used at microgram levels.
Mineral and vitamin-mineral premixes are highly popular in the baking industry, where they are used to fortify flours, breads, and other baked goods. A manufacturer can work with a premix supplier to specify which vitamins and minerals are required in their premix and also determine the overage levels required to keep the potency of the nutrients throughout the product’s shelf life.
The use of encapsulates helps to optimize high-speed forming operations by preventing salt-soluble proteins from accumulating on the equipment. This reduces patty adhesion and malformation and reduces cleaning delays, while increasing process yield and improving product consistency during processing.
Electrolyte Blues
Substances that form negative or positive ions upon dissolution in water are called electrolytes.
Calcium, magnesium, chloride, bicarbonates, potassium, and sodium are all examples of electrolytes. Typically, electrolytes appear in beverages—most commonly in sports and energy beverages. Such beverages can be still or effervescent, and may either contain sugar or be sugar-free. Electrolyte-containing stick packs or sachets that also have vitamin-mineral powders are increasingly popular. They’re marketed for enhanced energy, immunity, or to improve overall health.
Effervescent or fizzy products utilize acid-base chemistry via the rapid reaction of sodium- and/or potassium- bicarbonate with an acidic ingredient, such as citric acid. This reaction generates carbon dioxide in the form of bubbles, which help nutrients dissolve when a tablet or powder product is added to water.
While these products must be manufactured under low humidity, as moisture present in the air can cause the effervescent reaction to occur prematurely, the benefit is that the nutrients are dissolved in a buffered solution and can be absorbed more efficiently than ingesting a tablet or capsule.
The level of carbohydrates consumed right before or during exercising also is important. Drinks with greater than 10% carbohydrate can slow stomach emptying, cause abdominal cramping, and impair performance. Electrolyte replenishment is especially important for consumers engaging in exercise of more than 60 minutes at a stretch.
Ingredient Marriage
Some minerals naturally occur in an inorganic state, and some require conversion to a stable ionic form for optimal absorption. This conversion process is called “chelation” and involves a metal being bonded to an organic ligand, such as an amino acid like glycine or an acid. The ligand protects the ion from chelating with a stronger chelating agent that might trigger a reduced bioavailability.
A well-known example is the effect that vitamin C – ascorbic acid — has on increasing iron absorption by preventing the iron from binding to polyphenols or phytic acid. These compounds, present in foods, can cause ascorbic acid to also act as a reductant.
Minerals typically are compounded with a number of such chelators, such as citrate, malate, gluconate, bis-glycinate, and lactate. These ionic forms of minerals generally have a mild or neutral taste and can be favorable for use in a number of formulations. Sulfate, fumarate, carbonate, and oxide mineral forms are not as soluble or bioavailable in the body and less common in foods and beverages.
It is crucial to look at each compound individually since, for example, ferrous sulfate is highly soluble in water and is considered the gold standard of bioavailable iron for its ease of absorption. Yet ferrous sulfate will form oxides if left in a water base for too long, leading to severe color and taste changes in many foods.
While calcium citrate has a mild taste and is far more soluble than the carbonate form, it has a grittier mouthfeel. Thus, it is better suited for acidic beverages, such as orange juice, rather than for a baked product or nutrition bar, where mouthfeel is important to consumers.
The balance between solubility and palatability can be a delicate one. For example, when fortifying a fruit juice product with a more soluble form of calcium, product developers need to be careful, as the addition of tartaric acid can cause the formation of calcium tartrate — an insoluble precipitate.
Functional mineral chelates, such as trimagnesium citrate, tricalcium citrate, and tripotassium citrate, are being promoted for their high solubility, neutral-to-mild taste, and certain processing benefits. Tripotassium citrate is a highly soluble buffering salt for sodium-free pH-control in beverages and numerous food products. It is recommended in all dietetic food products that require buffering and a low-sodium content.
As a sequestering agent, tripotassium citrate complexes cations such as calcium, magnesium, and heavy metals. By creating these complexes, it enhances the stability of food and beverages during processing, heat treatment, and storage. Emerging research indicates that tripotassium citrate also can significantly increase bone mineral density and improve bone micro-architecture in healthy elderly people, according to Florentine Hilty-Vancura, PhD, a minerals expert and former senior scientist for the Human Nutrition Laboratory at the Federal Institute of Technology in Zurich. Hilty-Vancura stresses, however, that this research is preliminary.
Another type of ingredient marriage combines two ingredients that are synergistic.
A recent, small clinical study caught the attention of the sports product industry. The study suggested that a co-processed product containing amylopectin (derived from starch) and chromium might significantly increase muscle protein synthesis by 34% after four hours, when combined with a single dose of whey protein as compared to a whey protein control.
The trace mineral chromium is essential to the production of insulin and has been known to enhance the uptake of insulin, as well as aid in building muscle and burning fat stores. The research into this action of chromium has largely been confined to animal studies and, while promising, bears further attention.
Daily Dose
The need to include minerals—both macronutrients such as calcium and potassium, as well as micronutrients, from boron to zinc—into food and beverage products has become more essential than ever. Most consumers struggle to remember to take a dietary supplement and seek convenience, so beverages and foods are the most efficient way to get healthy minerals they need.
Formulators are developing improved products with nutrients to support the needs of the health and wellness customer. These convenient foods now include clinically studied ingredients to support bone, joint, and heart health, as well as the needs of growing kids. Based on key trends, manufacturers are incorporating calcium, magnesium, phosphorus, and potassium macronutrients. Micronutrients include boron, chromium, cobalt, copper, iron, manganese, molybdenum, selenium, silicon, strontium, vanadium, and zinc.
Selection of mineral fortification may require consideration of several factors:
- Mineral concentration
- Solubility
- Impact on flavor
- Caloric effect
- Stability or interaction with other components
- Particle size
- Density
- Compressibility
- Bioavailability
- pH
- Price per milligram for RDI
Performance Minerals
The category of sports performance and hydration beverages is one of the largest growing segments. They not only are designed to help athletes recover electrolytes lost during exercise but are great ways for non-athletic but active, stressed consumers to juggle work and an active home life.
The minerals featured most prominently in the sports beverage category are calcium, which is required for muscle contractions; and potassium, which is involved in muscle contraction and regulating water balance.
Magnesium also is required for proper muscle function and energy production. Sodium and potassium are essential in normal acid/base balance. These compounds also are important for normal cellular function and nerve actions, as well as kidney, cardiovascular, and lung function.
Beverage makers want to include performance ingredients but have been limited by large doses, insoluble ingredients, and unpleasant taste. To overcome, ingredient suppliers are developing and studying soluble ingredients, such as soluble minerals and better tasting or taste-neutral ingredients.
Food and beverage products featuring mineral fortification continue to expand, including dairy and dairy substitutes and bars, and even confections, such as calcium-enriched chocolates. Non-dairy beverages, and yogurt, ice cream, and cheese analogs have a special need for calcium and phosphorus. Whether from soy, almond, cashew, hemp, chia, pea, beans, or algae, the minerals calcium, phosphorus, and magnesium usually must be included in the formulation to fortify the product to be equivalent to natural dairy products or enriched dairy products.
Bars have become the epitome of convenience and nutrition in the past decade. They can be an ideal package, nutritious and convenient, and the sector continues to grow in variety and volume. When a bar is used to deliver a full complement of macro- and micronutrients, it can be the closest item to a mineral supplement that tastes great and is fun to eat.
When it comes to development and formulation of performance beverages, consultation with industry experts can speed up the identification of ingredients. This is true of enhanced waters, protein drinks, recovery drinks, meal replacements, fruit and vegetable juices, and other functional beverages. The same recommendation, of course, would apply to functional foods, dairy, bakery, and supplements.
Such ingredient scientists specialize in the food and beverage market and understand the functionality of ingredients, as well as their interaction and synergy with other components. Formulations for taste, texture, and nutritional quality all can quickly be developed with input from ingredient experts.
Let’s Get Smaller! Nanostructured Compounds for Food Fortification
By Florentine Hilty-Vancura, PhD
Effective food fortification with certain minerals, such as iron, is still a challenge for processors. Often, highly bioavailable compounds, like ferrous sulfate, cause severe color and taste changes in foods. On the other hand, compounds that are “well-behaved” in foods often are not bioavailable, thus are less effective in delivering the mineral to the person in need.
A new generation of food fortificants can be nanostructured or nanosized compounds. For example, reducing the particle size of iron compounds to the range of 10-100nm can increase the surface area exposed to digestion. This results in a faster dissolution in the stomach and thus a higher absorption in the intestine, compared with bulk-sized fortificants.
Animal studies have confirmed that nanosizing is effective in increasing bioavailability for iron, zinc, calcium, and selenium compounds. Iron as ferric orthophosphate is not highly bioavailable at bulk size, but becomes as bioavailable as ferrous sulfate–the gold standard for absorption–if nanosized.
Increasing the surface area in contact with the environment can also increase reactivity. Preliminary studies show nanosized iron can be used in neutral foods, although this science is recent and more studies are needed to confirm.
Nanostructured compounds can be prepared by milling an existing compound to a smaller size or by de novo synthesis, such as via flame-spray pyrolysis or precipitation. De novo synthesis opens a new area of designing compounds with specific chemical compositions or combinations with organic materials, such as acids or even proteins. It can be argued that mixing of different materials can be achieved easily and might not be beneficial.
In these novel compounds, however, the different components, e.g., iron oxide and zinc oxide, are not mixed as individual oxides but are atomically mixed. This means that in one particle, the iron and the zinc form a compound that actually is a molecularly mixed iron-zinc oxide.
This system of nanostructure can be expanded to other minerals, such as magnesium, calcium, and phosphate, and can be used to produce new customized compounds. The composition of such compounds can strongly influence the dissolution of the different elements combined in a single compound.
Such atomically mixed compounds have different properties than conventional mixtures of the same materials. For example, the iron in a mixed iron-calcium oxide iron is released faster than from a pure iron oxide.
Since nanosizing can increase the bioavailability of beneficial minerals such as iron phosphate, it also can potentially increase the bioavailability of contaminants. Thus, the strictest quality control for nanostructured compounds is required if used in foods. Safety of engineered nanomaterials in food is an ongoing challenge.
Since nanostructured food fortificants like iron phosphate or calcium carbonate are designed to quickly dissolve in the stomach and be taken up as ions in the intestine, it is less likely for nano-iron or other nanofortificant particles to enter the intestine and cause adverse effects. This is in contrast to persistent compounds like titanium dioxide or silica that do not dissolve in the stomach and for which safety is currently a prominent topic.
Current studies suggest dissolvable nanostructured iron compounds are safe. A recent meta-analysis concluded nanomaterials typically are less toxic than the respective dissolved metals, so any toxicity issues that could arise would stem more from increased bioavailability than from the particles themselves.
Consumer acceptance of engineered nanomaterials in foods is critical. Currently, consumers polled in Europe seemed skeptical about nanomaterials, based on a general aversion to engineered materials in foods. New food labeling legislation in the EU requires that engineered nanomaterials are labeled as “nano,” which could discourage companies from using them. These are marketing and communication challenges. Nanostructured minerals remain highly promising for effective food fortification.
Florentine Hilty-Vancura, PhD, is a Chicago-area minerals expert and the former senior scientist for the Human Nutrition Laboratory at the Human Nutrition Laboratory at Federal Institute of Technology in Zurich, Switzerland.
Originally appeared in the November, 2016 issue of Prepared Foods as Rock Out.
