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Challenges in Food and Beverage Stability

jun 14 2019

Chemical and physical destabilization of food and beverages is unavoidable, with numerous interrelated factors combining to alter the long-term thermodynamic behavior of food emulsions, suspensions and foams. This can have dramatic implications for product shelf-life, texture and mouthfeel, even flavor. 
Therefore, enhancing the stability of colloidal systems used in food goods and beverages is a high priority for conserving product quality over time and ensuring the best customer perception.

The underlying challenge of food and beverage dispersion stability is the complex nature of colloidal instability mechanics. Multiple destabilization phenomena can impact colloidal stability depending on the interacting raw materials in the dispersion, its environmental or storage conditions, and its method of application or delivery.

In this article, We outline some of the key challenges in food and beverage stability in more depth.

Ring Formation in Beverages

Ring formation is a common deterioration process affecting concentrated beverages. It is a form of creaming that occurs in the menisci of dispersions where surface tension causes the concentrated phase of this fluid to adhere to the inside of the container, forming a ring. 

This can take up to six months before becoming visible to the naked eye. But in order to maintain high quality products and efficient manufacturing process products must be tested in a much shorter time-frame.

Weighing agents, such as brominated vegetable oil (BVO), areoften diagnosed for limiting the effects of density differences between dispersive oil droplets and the aqueous phase to improve colloidal stability. However, BVO and other conventional weighing agents are considered unhealthy. Stability testing of beverages is increasingly concerned with the novel ingredients used to replace the likes of BVO.

Dairy Product Creaming and Flocculation

Creaming is a highly complex instability mechanic that is affected by various material properties and mechanical influences. It is a key phenomenon underlying the shelf-life of different milk products; the rate and severity of which will vary depending on fat content, homogeneity of fat globules in the aqueous phase, the presence of extra minerals like calcium (Ca) or additional additives like bacteria and proteins. Distinct products may also make dispersion stability testing more difficult. Fat- and sugar-free dairy products may exhibit vastly different instability kinetics or mechanics to typical products. 

Creaming will subsequently occur at different rates in the same conditions for homogenized and non-homogenized milk products, with the faster formation of thicker creaming layers associated with both full-fat and semi-skimmed non-homogenized milk.

Dairy products are characterized by such complex instability phenomena. Yogurt is formed via milk protein gelation, a form of flocculation that is characterized by several distinct kinetic regions (coagulation, bacteria growth, formation of jellified network).

Reconstitution of Food Powder

The dairy industry has historically avoided the issue of colloidal instability by dehydrating milk products into a powder that can be rehydrated on request. This is ideal, as powder is cost-efficient and space-saving, contributing to green initiatives. However, dehydration introduces a raft of additional challenges from a stability perspective. It is important to assess the properties of the reconstituted product to determine its similarity to the native form. Variations in global stability of rehydrated milk powders could suggest a comparatively poor-quality product or sub-optimal rehydration processes.

Food powder stability is often characterized by its dissolution kinetics, which are determined by parameters such as wettability, sinkability, and dispersibility. Assessing the dry powder quality for reconstitution in liquids may require a thorough understanding of how well a powder layer penetrates water volume (wettability), how quickly it can overcome liquid surface tension to sink into the fluid (sinkability), and the rate at which a sediment layer dissolves in the fluid (dispersibility).

Emulsifying Properties of Vegetable Proteins

Market challenges also represent significant obstacles to food and beverage stability, as the availability and cost of essential ingredients can dramatically affect returns on investment (ROIs) from end products. The availability of emulsifying proteins is a particular challenge, as these essential raw materials are subject to substantial market volatility and availability fluctuations.

Researchers are attempting to overcome this issue by evaluating the potential emulsifying properties of plant proteins such as pea and soybean extracts. Eliminating the use of animal proteins is now a matter of both commercial, ethical, and ecological importance. Plant proteins are currently a waste product with very low obvious value. Harnessing this waste for emulsification would have significant benefits to our planet, eliminating the reliance on animal products in-keeping with the ecologically-important trend towards veganism.

This requires a robust understanding of the global dispersion stability and stability kinetics of sample colloid, alongside the protein concentration and droplet size.

Food & Beverage Stability Testing with Formulaction

At Formulaction, we specialize in formulation stability testing, with a suite of advanced instrumentation designed with the complexities of food and beverage markets in mind. Our Turbiscan® series of instruments boasts accelerated analysis times of up to 200x that of visual testing, with reliable detection and quantification of any destabilization mechanic. There is no need for dilution as with alternative testing techniques, enabling accurate forecasting of the native product’s shelf life. 
The Turbicscan® range has already assisted in the evaluation of plant proteins efficiency as emulsifiers in food, the development of methods to estimate reconstitution of food powder in liquid, and much more.

If you have any questions about stability testing with our Turbiscan products, please do not hesitate to contact a member of the team directly.

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