Controlling stability for non-dairy alternative drinks

Market drivers

Alternatives to milk such as soy, almond and rice drinks, have gained in popularity in recent years. These dairy-free options can achieve similar mouth-feel and texture to traditional dairy products but, for example, with fewer calories and lower fat content. But working with such products is far from simple, with formulation and production challenges that are, in some cases, entirely new.

In this article, we’ve chosen to focus on how manufacturers can solve key formulation and production challenges around soy, rice and almond drinks – the three most popular non-dairy beverages on the market today. Products of this kind are typically composed of 0.5 to 3% protein, 0.5 - 3% fat, carbohydrates and fibres. The exact balance of such ingredients will depend in the specific nutritional profile the manufacturer aims to achieve.

If you’re experiencing stability problems with your non-dairy alternative drinks, the first thing to do is to check the formulation balance to ensure your recipe doesn’t exceed the expected range for each ingredient type. Next, take a deeper look at the raw materials and your production process, preferably together with emulsifier and stabiliser experts on hand to help you set up and make sense of testing.
In search of stability

Perhaps the most prominent challenge for those trying to produce good quality non-dairy beverages is product stabilisation. Due to the types of fat (with low saturation to deliver on nutritional claims) often used in such drinks, the emulsion is, by nature, very sensitive, with sedimentation, flocculation and fat separation as constant issues. One only has to think about what it’s like to open a can of coconut milk, for example, to realise that the ingredient’s rapid change from liquid to solid curd is likely to show up as creaming on the surface of a non-dairy alternative drink.

The souce for dry matter in non-dairy alternative drinks made from vegetable origin, such as rice and soy, usually contains high amounts of fibre or starch, i.e. some insoluble particles that need to be suspended during storage for the desired shelf-life of the final product. And, while the same goes for almond flour, there’s an additional challenge since almond paste is highly sensitive to heat, carrying an ever-present threat of flocculation following UHT treatment, with phase separation as a result.

It’s a multi-faceted, multi-ingredient landscape that can challenge even the best emulsion experts. Working with rice, for example, starch is the key issue; In soy drinks it’s protein; and in almond-based drinks the focus tends to be on flocculation. And the level of difficulty may well depend, too, on the form the various ingredients take – does the recipe call for paste or powder, or a liquid base? Do you want to work with a liquid soy base or solid proteins?

Advanced control

The unsaturated fat in the vegetable drinks demands strong emulsification ingredients, especially when long shelf-life products are produced. The introduction of the UHT technology has been incremental in achieving shelf-life of up to a year, depending on the composition of the product.

To address formulation and production challenges and exercise an appropriate degree of control over particle suspension and fat stability properties, a careful mix of emulsifiers and stabilisers is recommended: Whichever UHT system is used, the application of emulsifiers and stabilisers in soy, rice and almond drinks is necessary for ensuring optimal emulsion stability. Mono- and diglycerides of fatty acids, made from edible vegetable fats and oils are commonly used as emulsifiers in non-dairy alternative beverages. An emulsifier molecule has a hydrophilic and a lipophilic part and will consequently locate itself at the interface between the fat globules and the water phase. This happens during homogenisation of the drink. Emulsifier molecules also stabilise the emulsion, thereby reducing the fat separation in the product and improve the creaminess of the drink.

Figure 1: An emulsifier is a molecule with ambiphilic properties (part of the structure is hydrophilic and other moieties are lipophilic). In a multiphase system the emulsifier will adopt a favourable position with respect to energy. The emulsifier reduces surface tension between the phases.

Stabilisers are water-soluble polysaccharides extracted from land or marine plants or from micro-organisms. Adding stabilisers helps create the network required to suspend particles, increase viscosity, and improve mouth-feel. They are used for thickening and stabilizing properties. There are, however, many types of stabilisers available, each suited for different jobs, which means that picking the right combination requires specific know-how of the individual stabilisers and its synergistic effects with emulsifiers.

For almond, or rice drinks, for example, Palsgaard has developed Palsgaard® RecMilk 131, an emulsifier/stabiliser system that has shown consistently good results with high emulsion stability within a range of 0.18 to 0.20%.

Palsgaard® RecMilk 131 comprises a combination of mono- and diglycerides, and stabilisers – each performing a specific task in the final product. It’s a composition designed to suspend heavy particles and resist product changes in the face of elevated processing temperatures, provide a pleasant and creamy consistency and at the same time reduce separation during storage.

Almond drink, UHT treated    
Recipe:

Palsgaard® RecMilk 131
Sugar
Almond concentrate
Salt
Water

0.20%
2.00%
3.50%
0.10%
94.20%

Procedure: Add salt into the water
Add the almond concentrate
Add sugar and Palsgaard® RecMilk 131
Heat to 65 - 70ºC
Homogenisation 150/50 bar
UHT treatment: 138ºC / 7 seconds
Cool to below 25ºC and fill aseptically
 

Table 1: Recipe suggestion for the almond drink used to achieve results displayed in Figure 2.

Figure 2: Almond drink without Palsgaard® RecMilk 131 (left), almond drink with 0.2% Palsgaard® RecMilk 131 (right).

Figure 2 shows the results of recent tests run on a typical UHT almond drink without stabilizing additives and one with 0.2 percent Palsgaard® RecMilk 131 added (See the recipe in Table 1). A snapshot taken one month after production shows clearly visible curdling in the glass on the left. The glass on the right, however, containing the Palsgaard emulsifier system, displays no such curdling.

Interestingly, in beverages based on rice flour, the gelling effect and increase in viscosity typically caused by starch has not been observed when Palsgaard® RecMilk 131 is used, as displayed in Figure 3, suggesting this advanced emulsifier/stabiliser system may have an even wider range of applications in the dairy alternatives marketplace.

Procedure:

Add salt into the water
Hydrate rice flour in water at 50ºC for 20 min
Add Palsgaard® RecMilk 131
Homogenisation 150/50 bar at 65/70ºC
UHT treatment: 138ºC / 7 seconds
Cool to below 25ºC and fill aseptically

 
Rice drink, UHT treated    
Recipe:

Palsgaard® RecMilk 131
Sugar
Rice flour (Beneo)
Vegetable fat
Salt
Water

0.20%
5.00%
8.00%
1.20%
0.15%
85.45%
Composition of solids:

Fat
Solid non-fat
Palsgaard® RecMilk 131
Total solid, approx.:

1.20%
13.20%
0.20%
14.40%

Table 2: Recipe suggestion for the rice drink used to achieve results displayed in Figure 3.

Figure 3: Rice drink without Palsgaard® RecMilk 131 (left), rice drink with 0.2% Palsgaard® RecMilk 131 (right)

Another ingredient that is proving itself highly useful in non-dairy alternative drinks is Palsgaard® Chomilk 173, used in a range of formulations varying in processing conditions. Composed of mono- and diglycerides and stabilisers it can support the stability of cocoa powder or added calcium in soy-based products, too. See Table 3 for a recipe suggestion for a soy chocolate drink made with Palsgaard® Chomilk 173.

Procedure: Mix soy base and water at about 45-50ºC while stirring
Add in sugar and Palsgaard® ChoMilk 173
Add in cocoa powder
Heat to 70 - 75ºC for complete dissolution
Aseptic homogenisation 200/50 bar at 75ºC
UHT treatment: 140ºC / 4 seconds
Cool to below 25ºC and fill aseptically
 
Soy chocolate drink, UHT treated

 

 
Recipe:

Palsgaard® ChoMilk 173
Soy base (5.6% protein. 2.8% fat)
Sugar
Cocoa powder (10 - 12% fat)
Water

0.20%
53.60%
6.00%
0.80%
39.40%
Composition of solids: Fat
Protein
Sugar
Palsgaard® ChoMilk 173
Total solid, approx.:
1.60%
3.00%
6.00%
0.20%
13.50%

Table 3: Recipe suggestion for a soy chocolate drink

In line with many of Palsgaard’s other emulsifier and stabiliser products, both Palsgaard® RecMilk and Palsgaard® Chomilk are produced in CO2-neutral factories – and their palm oil components comply fully with the Roundtable for Sustainable Palm Oil (RSPO)’s Segregated (SG) supply chain requirements.

Making things better

If you’re experiencing stability problems with your non-dairy alternative drinks, the first thing to do is to check the formulation balance to ensure your recipe doesn’t exceed the expected range for each ingredient type. Next, take a deeper look at the raw materials and your production process, preferably together with emulsifier and stabiliser experts on hand to help you set up and make sense of testing.

With vegetable-based drinks (particularly cereals such as rice and oats) you may, for example, need to pay extra attention to upstream and downstream homogenisation, countering the effects of their starch content. For drinks produced using protein isolates, a holistic view on the product is recommended as i.e. protein salts and emulsifiers in interactions gives the right, stable emulsion.

Help is near

In most situations, the best and most reliable path to solving problems with existing recipes or developing new ones is to join forces with specialists in emulsifiers and stabilisers. And, as the inventor of the modern commercial emulsifier, Palsgaard is ideally positioned to help. We’ve been supplying both dairy and non-dairy producers with high-quality emulsifier systems for decades. At well-equipped application centers around the world, teams of application specialists work alongside you to determine the optimal mix of raw materials, recipe and process to achieve a stable product with the right sensory qualities. And we have the equipment needed to work with pasteurized, UHT-treated and sterilised products, making shelf-life studies covering the entire shelf- life of the beverage.