What’s bubbling under in yeast development?

Vince Bamford · 07 August, 2019

Suppliers continue to work on yeasts that play functional roles in baking – and there is more progress to come.

Think the role of yeast in baking starts and ends with making a loaf rise? Think again. Already, there are yeasts on the market that can delay dough development, offer similar benefits to bread improvers, boost vitamin content and more.

Acryleast, for example, is a clean-label, non-GMO yeast enzyme that claims to reduce acrylamide by up to 90% (see p41).
And further products are being developed that offer functionality.

“A yeast product development programme must seek to increase the industry profit pool, so delivering functional benefit to the baker and end-consumer is key,” suggests AB Mauri marketing business partner Sam Cook.

He adds that functional yeast developments should contribute to one of four key market drivers: flavour and nutritional enhancement, shelf-life extension, cost reduction or sustainability.

In the case of nutrition, yeast is already widely recognised as a source of vitamin B and for its probiotic quality.

Among those seeking to unlock new applications for yeast are researchers at yeast supplier Lesaffre, for whom nutrition is a key area of study.

“Yeasts are already widely used as dietary supplements when enriched with minerals such as zinc, chromium, copper, molybdenum and additional vitamin B,” says Sara Autton, technical manager at Lesaffre UK & Ireland. “There is no reason to suppose baker’s yeasts could not be developed with these beneficial characteristics for the benefit of bread consumers in the future.”

Consultancy Campden BRI also sees nutrition as an opportunity for yeast product development. “Marmite is one of the most famous by-products of yeast fermentation in brewing and a source of valuable B group vitamins,” points out Gary Tucker, head of Campden BRI’s baking and cereal processing department.

Yeast can also naturally produce vitamin D by reacting to ultraviolet (UVB) light. In technical terms, the yeast strain used for baker’s yeast – Saccharomyces cerevisiae – naturally contains ergosterol that is converted to ergocalciferol (vitamin D2) when exposed to UVB light. Lallemand has developed a process to treat baker’s yeast in this way to produce its Vita D yeast, which can be used in baked products as a source of vitamin D.

Another area where yeast has an impact is flavour. As well as making dough rise, fermenting sugars to make carbon dioxide produces by-products that contribute to bread flavour, and suppliers have developed yeasts to impart different flavours.

Lallemand, for example, produces Florapan aromatic yeasts, made from strains of wine and beer yeasts and designed to be used with, or instead of, conventional baker’s yeast to enhance the aroma.

In future, yeast could also have a role to play in extending shelf life.

“Beyond the nutrition and health aspects, there is the potential for the use of new yeast strains to improve dough performance,” suggests Autton. She adds that yeast could provide an anti-fungal activity, a view echoed by Campden BRI.

“We have interest in yeast for adding flavour and to extend shelf life without the need for propionate [a preservative used for preventing mould growth in baked goods],” says Tucker. Campden is working on two proposals in this area – one through agency Innovate UK and the other a ‘club’-funded idea in which companies jointly fund and benefit from research.

While the relationship between bakers and yeast goes back centuries, researchers have their vision set firmly on the future.

Licensing deal for Acryleast

Kerry has secured a licence agreement with Renaissance BioScience Corp to supply acrylamide-reducing yeast enzyme Acryleast to food and drink manufacturers.

The deal followed the introduction of new EU regulations to establish best practice, mitigation measures and benchmark levels for the reduction of acrylamide in food.

Acrylamide is created when foods, particularly starchy ones like bread, are cooked for long periods at above 120˚C. Tests have shown acrylamide causes cancer in animals and, while evidence from human studies is inconclusive, the scientific consensus is that it can cause cancer in humans.

Acryleast developer Renaissance BioScience Corp said there had been a lot of interest from food manufacturers globally for the enzyme, given changing regulations and consumer pressure.

Best tool for the job: the roles of functional yeast

Baker’s yeast (Saccharomyces cerevisiae, to give it its proper name) is typically available in three formats: liquid (or ‘cream’) yeast used by plant bakeries, blocks of compressed yeast or dried. Different types of yeast typically offer different rates of gassing activity. There are also yeast products that offer other features, such as:

Instant dry yeast – a reducing agent that increases the exten-sibility of dough and can be used for pizza bases and flatbreads;
Yeasts with functionalities usually associated with bread improvers, such as gas retention, dough stability and enhanced product volume.
Yeast where fermentation activity is controlled by cold temperatures, allowing delayed final baking without the need to freeze the dough. Lesaffre supplies the T-Control 4-10 yeast, which has very low activity when the dough is stored between 4-10°C, but normal activity at standard proofing temperatures. “This can be useful where it is important to minimise gas production during dough processing – for example, for croissants or Danish pastries,” explains Sara Autton, technical manager at Lesaffre UK & Ireland
Yeasts where the fermentation rate allows a wide tolerance to variable processing times – useful to protect against dough over-ripening in case of a plant breakdown.
Dry yeasts adapted for ready-to-use bakery mixes.