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Invert sugar in granular detail

15/02/2024 By Ibrahim Belo in Products

Invert sugar is a common industrial functional ingredient in bulk manufactured foods, drinks and medicines. It has many unique functional properties. In particular, it is used to enhance the quality, taste, texture and mouthfeel, as well as extending the shelf life of commercially made products. These include baked goods, confectionery, ambient and frozen desserts, drinks and medicines.

In the UK, the invert sugar market is expected to grow at a compound annual growth rate of 3.5% in the years to 2030, while growth forecasts for the wider European invert sugar market over the same period are slightly higher, at 4.4%. Despite rising demand among consumers for other natural sweeteners, invert sugar’s unique properties can support continued growth in the invert sugar market.

In this article, we explore what invert sugar is, what types are available, how it is made and how it is used.

What is invert sugar?

Invert sugar is sucrose, or table sugar, and water in liquid form. It has the appearance and consistency of a syrup, and is also known as invert sugar syrup, sugar syrup or simple syrup. It is called an ‘invert’ sugar because its optical rotation – the angle or direction at which polarised light passes through it and reflects off it – is in the opposite direction to sucrose, or table sugar. This inversion occurs because of how invert sugar is manufactured.

Fully inverted sugar syrup is a pale yellow following inversion.

How is invert sugar made?

Sucrose is a disaccharide comprising one glucose and one fructose molecule, meaning it has equal parts glucose and fructose. Invert sugar is made in a process called hydrolysis, which means ‘to break’. During the industrial process of manufacturing invert sugar syrup, sucrose (white crystalline table sugar) is combined with water and heated in an inversion pan.

Once heated, the chemical binds holding the glucose and fructose molecules together break apart. This leaves a liquid sugar or sweet syrup that is 50% glucose and 50% fructose. As fructose is sweeter than glucose or sucrose, invert sugar is sweeter than sucrose.  

At Ragus, we manufacture pure invert sugars. One of Ragus’ products is invert sugar syrup, which is often the name used for commercially manufactured invert sugar. 

Types of invert sugar

The way invert sugar is manufactured, otherwise known as the inversion process, enables invert sugar producers like Ragus to produce different invert sugars with certain properties for use in specific applications. A leading invert sugar manufacturer in the UK, Ragus manufactures two types of invert sugar syrup: fully inverted sugar syrup and partially inverted sugar syrup.

Fully inverted sugar retains less sucrose as most of the sucrose has been converted into fructose and glucose molecules. It is 3.5-5.5% sucrose to 71-77% invert. It is around 40% sweeter than sucrose and 20% sweeter than partial invert sugar syrup. It is more yellow in appearance compared to partial invert sugar syrup as it is inverted for longer.

Partially inverted sugar contains more sucrose following its production process, as it is only partly inverted. It is 32.5-35.5% sucrose to 42.5-45.5% invert. Partial invert sugar is 20% sweeter than sucrose but less sweet than full invert sugar. It is often used to help prolong the shelf life of a product. Golden syrup is a well-known partial invert syrup.

The invert sugar syrup manufacturing process

To manufacture full invert sugar syrup, water is heated in large-scale inversion pans to 70°c. Sucrose is added to create a sugar saturation before an acid is introduced to bring the pH down to 1.6. These three elements, sugar saturation at a temperature of 70°c and at a pH of 1.7, results in the sucrose breaking down, or inverting, into fructose and glucose. 

Manufacturing invert sugar syrup in an inversion pan.

For a full invert sugar syrup, the reaction is allowed to continue until the brix is 76%, and the polarisation is -18 to –22, at which point a natural alkaline agent is added. This brings the pH to between five and six. Colourless full inverts are cooled and packed as soon as possible to avoid caramelisation.

Partial inverts are manufactured using a slightly different process. With full inverts, all the sucrose is added at the start, but to produce a partial inverted sugar syrup, the sucrose is added in two stages. The initial stages are the same, heating the water to 70°c and adding the sucrose, and reducing the pH to between 1 and 1.6. The difference is that less sucrose is added initially, the remainder being added after inversion.

Inspection and quality control underpin our manufacturing processes.

Once all the sugar crystals are dissolved and the temperature is over 70°c, the sucrose will invert into glucose and fructose. After the desired ratio of sucrose to fructose is achieved alongside a polarisation of -14, the syrup is neutralised with a natural alkaline agent and the remaining sugar is added.

Golden syrup, another product Ragus manufactures and an important one in our company’s backstory, is a type of partial invert sugar syrup. Golden syrup does not differ from a ‘regular’ partial invert in how it is made until the final stages of the manufacturing process. Through heating and ageing, further caramelisation occurs, and sucrose is added at the end. This makes it a mixture of invert sugar and sucrose.

Golden syrup, invented by Ragus’ founder Charles Eastick, is a partially inverted sugar syrup, which undergoes a subsequent caramelisation stage after inversion to give it the distinctive amber gold colour.

To add colour to partial inverts, for darker syrups such as golden syrup, the mixture is caramelised in the inversion pans. The temperature and times will vary according to the desired flavour and colour profile. Once the remaining sugar is added and dissolved, for golden syrup, the brix will be a maximum of 83%, and the polarisation +20.

Quality control in making invert sugar syrup

As part of the quality control process, various measures are implemented during the manufacturing of invert sugar syrups. Measures include testing for brix levels, the desired colour and consistency.

As with every product Ragus manufactures, quality control and responsible sourcing is at the forefront of our invert sugar syrup production process. We only work with approved suppliers and maintain an audit trail across our supply chain. This audit trail enables us to be transparent and prove provenance to our customers.

For food, beverage and pharmaceutical manufacturers looking for an invert sugar supplier in the UK whose products are made from responsibly sourced ingredients, Ragus is that supplier.

Invert sugar syrup: applications and benefits

Invert sugar is present in many foods, beverages and medicines. For example, it can be found in:

  • Soft drinks

  • Baked goods, such as cookies

  • Toffee

  • Fudge

  • Caramel

  • Fondant icing

  • Sweets, such as liquorice

  • Ice cream and sorbet

  • Cough syrup

  • Kombucha

  • Frozen cocktails

In these products, invert sugar has many functions. For example, it can enhance the flavour and colour of a product, which is important for confections like fudge or toffee. Invert sugar also helps reduce crystallisation, which means a product can remain soft and stable for a longer time, maintaining expiration life. Invert sugar also depresses the freezing point of ice creams and sorbets, making them easier to scoop. 

Invert sugar, especially partial invert sugar, is a humectant. This means it helps to keep products moist, thereby supporting preservation. When manufacturing cakes or biscuits that require long shelf life, this is a useful characteristic. 

For soft drinks, invert sugar’s ability to easily dissolve in cold liquids makes it better than sucrose as a sweetener. In drinks that would otherwise be acidic or tart due to their fruit content, invert sugar is necessary to balance out this acidity.

Ragus’ recommendations to invert sugar and bulk invert sugar customers for storage and packaging

When storing invert sugar products, whether in bulk or smaller quantities, it is important the product maintains its quality and crystallisation/spoilage does not occur. This is especially important when bulk invert sugar is supplied for use in pharmaceutical products.

For this reason, we check with our customers on everything from access to temperature-controlled storage facilities to the most appropriate packaging.

As a bulk invert sugar manufacturer, we aim to provide our customers with what they need for their products. We usually start by asking questions such as:
* How much invert sugar will you use each month?
* What type of packaging is best for you, based on what we have available? The options include intermediate bulk containers (IBCs) and bulk road tankers.
* What are the ambient conditions of your storage location? Invert sugar syrup should be stored away from direct sunlight in a dry, cool environment at an optimal temperature of 15-20°c.

Once we have answers to these questions, we can supply you with the right type and amount of invert sugar syrup. 

Invert sugar syrups are packed and delivered to our customers in 1000l intermediate bulk containers (IBCs) and 30,000l bulk road tankers.

Full inverts behave in the same way as honey. This means they can begin to crystallise in cold temperatures after four months of storage, with a shelf life of around six months.

Partial inverts, such as golden syrup, have a shelf life of six months before crystallisation and 12 months before spoiling. Any invert sugar that goes into storage, particularly full inverts in bulk tanks, must go into trace heated tanks to prevent crystals from forming. 

Ragus supplies full and partial invert sugar syrups to industrial food, beverage and pharmaceutical customers to maximise taste, texture, appearance and shelf-life. To learn more about our pure sugars, contact our Customer Services Team. For more sugar news and Ragus updates, keep browsing SUGARTALK and follow Ragus on LinkedIn. 

Ibrahim Belo

With a primary responsibility for manufactured product quality control, Ibrahim works within our supplier chain, factory and production laboratory. He has a focus on continuous improvement, implementing and maintaining our technical and quality monitoring processes, ensuring standards and product specifications are met.

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