Mastering The Art Of Suspension & Stabilisation
Monday, June 8th, 2020
The opportunities for stabilisers in the multi-faceted, multi-ingredient dairy beverage market are endless. By CP Kelco.
What goes up must come down. We learned this from studying Sir Isaac Newton’s universal law of gravity. This concept is what affects the stability and particle suspension of your dairy beverage formulation. It also could affect what consumers see when they pour a glass of your product. Will the protein, calcium, minerals and fun inclusions such as nata de coco remain evenly dispersed? Will chocolate milk stay chocolatey in taste and colour? Will every serving of your beverage retain equal amounts of the nutrients that you promised on the packaging?
If you’re working with plant-based protein in addition to or instead of dairy, it has its own set of challenges. Some legumes, nuts and grains can become gritty and leave an unpleasant taste. Some have higher amounts of fibre or are sensitive to heat.
Stability refers to the visual uniformity and even distribution of your product. Fat separation is a constant issue. Heat processes promote chemical changes that impact flavour, colour, nutritional value and stability.
Suspension refers to how well insoluble ingredients, including protein, remain thoroughly blended in liquid—both in the manufacturing process to ensure even filling of particulates in packaging, and also over the shelf-life of a product. This usually requires some outside force to help.
Suspension agents are the outside force that formulators use to counter the law of gravity. You can either accomplish this job manually through constant shaking or by using a hydrocolloid. The name ‘hydrocolloid’ gives us a clue as to how it works. ‘Hydro’ means water and ‘colloid’ means gelatinous, so we know that it uses water binding to achieve stability.
There are many factors that go into choosing an ingredient to help with stability and suspension. It’s both an art and a science. Hydrocolloid ingredients play an important role in adjusting the rheological properties of beverages. Typically produced from the land, sea or micro-organisms, their main job is to enhance the stability of a dispersed system by acting as thickeners or gelling agents.
Some points to consider when seeking a suspension agent or stabiliser:
- Total protein content
- Type of protein used (dairy or plant-based)
- Other ingredients you’re adding: inclusions, vitamins, flavourings, sweeteners
- The pH of your product (neutral or acidified)
- Is heat treatment or pasteurisation involved?
- Are you also trying to reduce sugar or fat content?
It’s also important to consider your desired texture at this stage of formulation. In dairy, the most coveted texture is creamy with good mouth-coating characteristics. However, drinking yoghurt preferences vary widely from thin to an almost-spoonable thickness. Unique added inclusions such as nata de coco, fruit, tapioca pearls and cocoa need special care. The combination of low pH and heat treatment can be another obstacle. As you can see, a lot is riding on your choice of suspension agent.
How Suspension & Stabilising Agents Work
Gellan gum is a nature-based ingredient produced by fermentation of a pure culture of the bacteria Sphingomonas elodea. Using fermentation ensures a reliable supply and consistent quality with a composition identical to the organism that forms in nature on lily pond plants.
Gellan gum works by forming a fluid gel network with monovalent and divalent cations, such as calcium, upon cooling. The fluid gel is a solution with a weak gel structure. A finite stress must be exceeded before the system will flow. These systems are very good at suspending particulates. If the stress exerted by gravity on the particles is less than the yield stress, the suspension will remain stable. (Back to Newton again!) Its highly pseudoplastic flow provides efficient suspension combined with low viscosity at higher rates of shear. This results in low viscosity in the mouth. Gellan gum is one of the only hydrocolloid ingredients like this so it’s often used for flavoured dairy milks and plant-based beverages that have a neutral pH.
Gentle agitation of a weak gellan gum, after it has set, is also sufficient to form a smooth, pourable fluid gel. This means that fluid gels can be formed using standard filling operations. Gellan gum is effective at very low concentrations and doesn’t mask flavours. Many grades will disperse in temperatures that vary from chilled to heated up to 85 degrees Celsius. In ambient drinking yoghurts, gellan gum provides additional stability and mouthfeel, forming a fluid gel in the serum phase to suspend proteins, reduce syneresis and interact with the casein to strengthen and stabilise the protein network. It can also be used in combination with another stabilising agent, mainly pectin.
Pectin is another widely used ingredient in acidified dairy and plant-based beverages such as drinkable yoghurt and milk-juice combinations, plus acidified whey and soy drinks. Made from citrus peels, this label-friendly ingredient helps to stabilise milk proteins while also contributing to the mouthfeel. In products where artificial sweeteners are used, pectin imparts a pleasant flavour profile.
When drinks containing protein are heat treated in a low pH environment, the proteins tend to aggregate, create lumps and settle on the bottom of the container, which results in an unstable—and unsightly—beverage. Pectin is attracted to positive protein charges. Being negatively charged, pectin interacts with casein molecules through calcium ions to prevent sedimentation and serum separation. Using electrostatic repulsion, pectin covers the casein molecules so they stabilise, even during heat treatment. This allows drinks to be produced with a longer than normal shelf-life and low tendency to create sediment. The pectin also creates a network in the drink that improves the stability of short shelf-life fermented drinks. The optimal stabilising effect is seen in the pH range of 3.8 to 4.2.
Another proven, nature-based ingredient is carrageenan. Derived from red seaweed known as Irish moss, carrageenan has been used for centuries as a gelling agent in neutral pH dairy products. It also provides multiple functionalities to help reduce ingredients in your formulation, including help with suspension, protein stabilisation, mouthfeel, body and emulsion stability, all in one. It can prevent creaming over shelf-life, including in hard-to-stabilise coconut milk.
The opportunities for this multi-faceted, multi-ingredient dairy beverage market are endless! However, as new ideas for product development arise, so do the challenges. Luckily, there are a number of efficient and effective ingredient solutions. Answering today’s challenges takes technical depth and insights culled from years of experience working with these nature-based ingredients. Whatever your suspension and stabilisation needs, you can count on CP Kelco to help. Our regional R&D experts can provide formulation and process modifications to ensure you achieve your beverage masterpiece.
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