Whether for health reasons, convenience or taste, consumers across the world are eating more and more yoghurt. Traditional large consumers such as France and Turkey are still going strong, but in developing countries consumption is now also rising fast.
While tastes vary – from local favourites to Greek-style yoghurt to sweetened yoghurt with added solid ingredients or flavours – a common challenge for producers is that yoghurt is so sensitive to mixing. If mixed too hard and fast, it can break down to give an undesirable fluid consistency or separate, forming a liquid layer.
Added ingredients like fruit pieces are also fragile, and need to be handled gently in order to maintain their shape and texture. Particles and fruit fibres can also become trapped in the cracks and crevices of the equipment, causing hygiene problems.
Gentle and hygienic mixing
To meet these challenges, Tetra Pak offers the A-line static mixer, which – unlike many generic models – is optimized for the food industry. “Overall, this mixer is very gentle on the ingredients it processes, promoting quality, enhancing food safety and reducing waste,” says Fredrik Innings, Key Technology Manager at Tetra Pak and Processor of Food Engineering at Lund University.
The mixer blades do not move. Instead, the liquid is mixed as it flows over them. The key advantage is that the blades are evenly curved and have a shallow angle, ensuring that the product is mixed gently. Innings says: “The blades are also thicker than in other mixers, making them easier to clean. And their smooth design helps prevent fibres and particles getting stuck.”
Hygiene is further promoted by the welded construction of the mixer, which eliminates the uneven surfaces that might otherwise trap food particles. The A-line static mixer from Tetra Pak is also made for CIP (cleaning in place) and is always perfectly clean after a CIP cycle. Eliminating the risk of human error, CIP is highly effective and it saves time, as operators do not need to dismantle the mixer to clean it.
To successfully achieve the producers’ ambitions requires a thorough understanding of the science behind yoghurt production.
“Although the A-line static mixer has a relatively long history, we have introduced significant improvements to it in recent years,” Innings explains. “These improvements were based on a careful study into how to optimize the mixer’s performance to meet the needs of individual customers. We can now, for example, vary the number and size of the blades depending on the physical difficulty of the mixing task.”