How to achieve perfect melting resistance in ice cream

The right melting resistance is in the eye of the beholder

“Melting resistance is usually one of the first things our customers want to talk about,” says Claus Prior Hansen, Application Manager, Ice cream & Dairy, at Palsgaard. “It’s extremely important because it’s so visual and so obvious to consumers. When little Peter is eating his ice cream, if he’s taking his time, suddenly he’ll find that half of it is on the floor.”

So what’s the ideal melting resistance? “There are as many views on that as there are producers and consumers,” Claus says. “I can visit one customer who wants a product that will stand on the table for an hour and a half and keep its shape. And right next door to them, there’s another who wants something that starts to melt in ten or fifteen minutes, because if it doesn’t, it won’t look like ice cream. It’s all in the eye of the beholder. We don’t set the goal – the customer does, and it’s up to us to find a way to achieve it.”

He adds that the application is also a major consideration. “If it’s a single-serving product, like a cone or a sandwich, it needs to have relatively strong melting resistance, because it’s going to be held in someone’s hand. Whereas products that are sold in larger volumes – family-size buckets for example – don’t necessarily need such strong resistance.”

When we talk to customers, we talk about their whole processing, and we’re often looking to see if there are other factors we can adjust. Emulsifiers are critical but you need that total overview.

Controlling melting profile with emulsifiers

The good news is that the right ingredients can help regulate the melting properties of ice cream. Emulsifiers place themselves in the layer between fat and water, displacing the protein on the fat globules and reducing surface tension. As well as benefits like improving mouthfeel, this affects the stability of the ice cream, and the speed at which it melts.

Palsgaard’s emulsifier solutions include the Palsgaard® ExtruIce range for extruded ice creams – typically single-serving products like cones that need a stronger emulsifier. Meanwhile, the Palsgaard® MouldIce range is perfect for moulded ice creams, which tend to require a less powerful melting resistance.

Claus works with customers to achieve exactly the right emulsifier-stabiliser combination for their needs. “Melting resistance is definitely something we can influence, correct and improve upon,” he says. “Switching emulsifiers is the easiest way to get a benefit – we can do a lot just by changing from one Palsgaard® ExtruIce product to another.”

Unlike many alternatives on the market, Palsgaard’s products are fully integrated blends. “The stabiliser is covered by emulsifiers in a powder,” Claus explains. “That makes it very easy to handle and very easy to add to the liquid because it’s highly dispersible. The alternative is having to mix two or three powders, which is more time-consuming.”

Palsgaard offers ready-mixed emulsifiers and stabilisers as unique, integrated products. The suspension of stabilisers in the melted emulsifiers, followed by an advanced spray-crystallisation process, transforms the product into a uniform, free-flowing powder - illustrated in the microscope photo on the left. The microscope photo on the right shows a dry mix for comparison.

The total package – other factors that affect melting properties

“Of course we’d like to say it’s all about our emulsifier products,” Claus says. “And that’s true to a large extent because if you don’t add any emulsifier at all, you’ll end up with a product that melts very quickly. But it’s also about the whole package. Ultimately, the emulsifier accounts for quite a small proportion of the ice cream, so we’re also dependent on factors like the choice of other ingredients. If you’re using the wrong kind of fat, even our products can struggle to solve problems with melting resistance. Then there are water-soluble ingredients like milk powders – they can really affect structure too.”

“Sometimes you also need to look at your processes and the way you’re handling the mix,” he adds. “There could be just one step in the process that’s ruining everything. For example, after you’ve processed the mix, you need to age the mix for at least four hours – preferably 24 – before you freeze it, but some producers shorten this ageing time because they’re in a rush. They can have the best raw materials, the best emulsifiers, the best freezers, the best processing line, but if they shorten the ageing time, they mess everything up for the sake of saving a couple of hours.”

“So when we talk to customers, we talk about their whole processing, and we’re often looking to see if there are other factors we can adjust. Emulsifiers are critical but you need that total overview.”

The evolving science of melting resistance

Emulsification technology has been evolving for decades, with solutions such as monoglycerides and diglycerides becoming common some decades ago. “That was the big shift,” Claus says. “Ice cream manufacturers were able to switch away from egg yolk to industrially produced emulsifiers, and it changed the whole approach to stability.”

Meanwhile, digital technology now allows melting properties to be monitored to a high degree of accuracy. Palsgaard uses its own proprietary software in conjunction with a temperature control chamber and digital scales. As the ice cream melts, the program records the drop-off by weight and calculates the percentage loss.

“It gives us a complete digitised curve based on up to eight trials running concurrently,” Claus says. “It allows us to conduct a very detailed analysis of the ways different factors are affecting melting. And It’s really visual, so it’s a great tool for showing to the customers.”

Palsgaard uses its own proprietary software in conjunction with a temperature control chamber and digital scales. As the ice cream melts, the program records the drop-off by weight and calculates the percentage loss.
An example of a melt-down trial of two ice creams, one made without emulsifiers and stabilisers and one with a Palsgaard® ExtruIce system.
  1. Use the correct emulsifier and stabiliser system - without emulsifiers, you’ll have a product that melts very quickly
  2. If that’s not enough, review other ingredients, like fat and milk ingredients
  3. Look at your processing – if you’re doing something wrong, it doesn’t matter how great your ingredients are
CLAUS PRIOR HANSEN’S TOP THREE TIPS FOR CONTROLLING MELTING RESISTANCE

PHO-free, palm-free, CO2-neutral

However, strategies to control melting resistance need to be based on more than science – consumers’ health needs, and their ethical concerns, increasingly have to be factored in. “A lot of ice creams used to contain PHOs (partially hydrogenated oils),” Claus says. “In the past, that wasn’t seen as a bad thing, because it was a good way of improving melting resistance. However, they’re a source of trans fats, so right now there’s a lot of pressure to go PHO-free.”

The other big demand is for products that are palm oil-free. “We’ve been working a lot on those areas,” Claus says. “It’s been a bit of a challenge to get the same functionality and mouthfeel as well as melt resistance, but now we can provide products that meet all those needs. For example, we’ve just launched a new range of emulsifier-stabiliser blends which contains tara gum that are both palm-free and PHO-free. That’s the way the market is moving, and by being able to offer them, we’re a little bit ahead of some of our competitors.”

Another big selling point for Palsgaard is that it produces all its products in CO2-neutral facilities.

“We’re the only emulsifier provider that can make that claim”, Claus says. “When we highlight it to customers they see it as something new in the market that will help them stand out. Even in regions like the Middle East, where sustainability hasn’t always been a big focus in the past, manufacturers are starting to see that it’s an area they should be looking into.”

Growing concern about climate change has also meant that Palsgaard is being called on to improve the melting properties of plant-based frozen desserts. “The process is parallel to traditional dairy ice cream in some ways,” Claus says. “We can control a lot of the factors but it’s a little more complex because there are so many different raw materials – soy, almond, coconut, for example. The good thing is that our emulsifiers are based on vegetable oil and our stabilisers are plant-based, so they’re ideal for non-dairy products.”

You can find out more about Palsgaard’s solutions for plant-based desserts here, and it’s an area we’ll be returning to later in our “How to” series.

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