The international patent application, filed by Vevey, Switzerland-based Nestlé last month, details a process for the manufacture of yogurt and frozen yogurt with a protein content of between 5% and 14% and a lactose content of 7% or less by weight.
Greek yogurt products, which are manufactured traditionally using straining methods, typically contain around 10g of protein per serving.
Nestlé’s claims that its patent-pending process, invented by US-based Nestle R&D duo Matthew Galen Bunce and Rajiv Indravadan Dave, produces yogurt products with a protein content of up to 14% “without straining the milk at any stage and without adding protein to the milk at any stage.”
“The yogurt can be made using standard production equipment without additional equipment for adding protein, equipment for straining the yogurt and equipment for disposing by-products of straining,” said the patent application.
Nestlé added that regular skim milk, where all cream is removed from whole milk, is "not capable of providing a high protein content without using added protein or straining the yogurt."
Whey protein, milk protein concentrate (MPC), and protein isolates can be added to increase the protein content of a yogurt, but "this increased amount of total solids in the yogurt can result in poor textual quality of the yogurt," it said.
“Moreover, straining yogurt requires additional equipment and creates acidic whey, a by-product of straining, that must be disposed or used in an alternative way."
Gritty texture
Yogurt products made using conventional skim milk typically boast a protein content of between 3% and 5% and lactose at levels of between 5% and 7%, said the patent.
A "non-limiting example" given by Nestlé compared a reduced-lactose skim milk-based yogurt mix with one produced using regular skim milk and MPC.
When measured, the reduced-lactose skim milk mix was found to contain 3.2g of lactose per 68g serving (4.6%) and a protein content of 6g per serving pre-fermentation.
The regular skim milk yogurt mix contained a competitive 6g of protein per 71g serving, but 8.2g of lactose (11.6%).
A third yogurt mix of regular skim milk with no added MPC, meanwhile, contained 5.44g of lactose per 71g serving (7.66%) and a protein content of just 4g per serving.
Nestlé concluded, therefore, that "using lactose-reduced skim milk in yogurt as disclosed herein enables an increased protein level without additional lactose and, as a result, prevents gritty texture due to lactose crystallization."
“This low level of solids and increased protein content, such as 6g of protein per serving, cannot be achieved by regular skim milk without the addition of WPC, MPC, protein isolates or the like.”