Optimised shelf life and better handling for foodstuffs

For powdered foods, the main cause of food loss has always been ‘caking’, a phenomenon that causes the deterioration of the product’s properties and appearance. Fortunately, anticaking technology is continually advancing, giving the food industry the tools it needs to harness the market opportunities that exist in powdered foods whilst contributing to food waste reduction efforts.

Caking can occur for several reasons, spanning both internal and external factors. Critical steps in the production process are primarily transportation and storage.

In most cases, caking is caused by absorption of moisture from the environment, when powders are exposed to high relative humidity. Temperature shocks can also induce caking by causing the particles to stick together. Internal factors leading to caking include electrostatic interactions, water bridges and particle shape. For prevention better packaging, a decrease of moisture during processing and in the final product as well as a throughout control of the ambient parameters temperature and humidity could be helpful. All means cause costs and efforts.

To avoid caking, powders should be free-flowing and dispensable. Common anticaking agents include silicon dioxide, tricalcium phosphate, magnesium oxide and calcium carbonate. They are distributed sparingly over the particle surfaces or in between particles decreasing mechanical interlocking. The distance between the particles raises and reduces the Van der Waals forces of attraction. Anticaking agents also absorb moisture. The particle surface cannot form liquid bridges while the particle itself is completely coated.

Non-nano, low dusting and digestible alternatives with more robust safety profiles have emerged, with Omya’s anticaking solution a frontrunner. It is based on functionalized calcium carbonate particles that have undergone a patented recrystallization process to create a new mineral composition and structure. The resulting non-nano mineral offers high porosity, enabling it to absorb and entrap excess moisture and acting as a spacer between the host powder particles, keeping the mixture flowing freely.

The challenge when working with anticaking agents is that the effectiveness of the agent in preventing moisture-induced caking is influenced by the composition of the host powder as well as the interaction with environmental moisture.

The food industry uses a diverse range of powdered ingredients, from starch, salt, ground spices, soups, gravy, milk powder and infant formula to cocoa and protein powder. These ingredients vary greatly in their surface chemistry and physical properties and their caking behavior is correspondingly complex. As each powdered product has a unique composition, it is not possible to predict caking behavior without performing tests.

The effectiveness of anticaking agents can be established via two quantifiable metrics: flowability and caking. Flowability is the more straightforward characteristic to quantify and can be measured via flow funnel, angle of repose, shear cell or powder rheometer. Caking is more difficult to quantify, but Omya has worked on this challenge together with Freeman Technology which developed a method that uses the FT powder rheometer. As a result of this collaboration, Omya can now assess the anticaking performance of different candidates and support customers in finding the best solution for their products.

The first step is to ascertain whether the caking that is occurring is homogenous or non-homogenous. Homogenous caking is when the moisture has migrated throughout, and the entire powder bed is caked. Non-homogenous caking is when the powder is crusted at the surface but the material beneath is unchanged. It is possible to determine this with a powder rheometer caking test. The results, presented in graphical format, will show where, within the samples, there is greater resistance to flow and how this alters with different relative humidity levels and temperatures.

Once characterized as homogenous or non-homogenous, the caking of the food matrix can be quantified with and without anticaking agent at different temperatures and humidity conditions.

When the caking is non-homogenous, crust depth is measured; the bigger the crust depth, the more caking is occurring. When an anticaking agent is introduced, this should reduce the crust depth.

When the caking is homogenous, Caking Index (CI) is the value measured. This is the ratio of the energy of the caked sample to the energy of the fresh powder before storage. CI is bigger when more caking is taking place and should decrease when an anticaking agent is added to the powder.

The breakthrough tool developed by Omya and Freeman Technology enables comparative assessments of anticaking agents in different food powders and offers some potential to predict the effect of anticaking agents. When used in combination with other traditional analysis methods, it allows food technologists to demystify the behavior of anticaking agents in food and nutritional powders, experiment with different approaches and determine the optimum solution for the application in hand.

For example, it has been used to test the effectiveness of a calcium carbonate (cc) anticaking solution compared to silica in spice mix and milk powder. As shown in the figures, with the addition of 1% cc anticaking solution it is possible to decrease caking by up to 50% in severe conditions.

The samples were kept under severe conditions (30°C temperature and 70% relative humidity for an extended period). The crust depth was measured and displayed in Figure 1. The crust depth decreased when the anticaking agent was added, demonstrating the effectiveness of the Omya product in comparison to a conventional solution.

The new functional mineral solution can also score highly in giving greater flowability to food powders - a key element for better processing conditions and throughput of food processes.

Thanks to profound testing experience and the company's own laboratory, Omya can provide customers with initial reliable data on the performance of the new anticaking agent for their products.

The various anticaking solutions on the market demonstrate similar performance in reducing humidity and coating particles to improve flowability and reduce clumping. In this regard, the mineral solution based on calcium carbonate shows comparable effects to silica and magnesium oxide. An important additional feature of functional mineral particles such as Omyafood is that they are non-nano and less dusty and therefore safer in the production line as well as for operators and consumers. Moreover, this solution is digestible and does not accumulate in the body.

Besides food safety, food waste is another topic gaining more and more focus: For the EU, the European Commission is preparing to introduce legally binding targets to reduce waste in stores, restaurants, and households by 30% per capita by the end of 2030. In addition, a 10% reduction binding target will be put in place to tackle losses during the processing and manufacturing of food.

For both missions, an anticaking aid with functional mineral particles would seem to be a promising approach.

Renata Negrini, Technical Service Manager Consumer Solutions, Omya International AG, Switzerland
Renata.Negrini@omya.com
www.omya.com