Steve Campbell describes recent advances using baker’s yeast to reduce levels of acrylamide in baked products.
Acrylamide health risks
The European Food Safety Authority (EFSA) released its first full Scientific Opinion on Acrylamide in Food in June 2015, which confirmed its previous opinion that ‘acrylamide in food potentially increases the risk of developing cancer for consumers in all age groups (1).’ This conclusion is based on numerous animal studies that have unequivocally shown that acrylamide, along with its metabolite glycidamide, are genotoxic and carcinogenic, meaning that they can damage DNA and cause cancer. The EFSA report has been submitted to the European Union to inform decision makers considering policy measures to reduce consumer exposure to acrylamide in many commonly consumed food products. Acrylamide poses an elevated health risk to children (2, 3). The acrylamide in foods consumed by pregnant women has been shown to reduce birth weight and head circumference, key indicators of a child’s future health (4, 5). Critically, because of their smaller size and the types of foods they consume, young children are typically exposed to twice as much acrylamide, per kilogram of body weight each day, as adults (6).
Dietary acrylamide exposure has been a serious concern since 2002 when Swedish scientists first discovered the carcinogenic chemical in many commonly consumed foods (7). Since then, government food safety agencies worldwide have confirmed and monitored its presence in many different and widely consumed foods, including processed potato products, such as potato crisps and chips, and other snack foods, such as biscuits, crackers, bread, toast, and coffee (8, 9, 10). Importantly, acrylamide is not added to food, but instead forms primarily when food containing asparagine, a naturally occurring amino acid, is fried, baked or toasted above 120°C.
Potential for acrylamide reduction
In order to meet potential acrylamide regulatory limits, food manufacturers worldwide require robust and effective tools to reduce acrylamide levels in food. So far, workable solutions to the acrylamide problem have been hard to find. However, a non-GMO, baker’s yeast (Saccharomyces cerevisiae) with the ability to reduce acrylamide by up to 95% with minimal changes to the food production process has been developed by Renaissance Ingredients Inc. of Vancouver, Canada. Although baker’s yeast has a natural ability to consume asparagine, under most food processing conditions this asparagine consumption is minimal. The yeast was developed using a classical adaptive evolution strategy to select for the yeast’s ability to quickly degrade asparagine in all conditions. Renaissance has filed an application for a provisional patent on the technology.
Potato crisps and chips
As fried potato products have become increasingly popular, they represent a significant health threat to consumers because they can provide up to 50% of the daily dietary acrylamide exposure of adults. The ability of a ‘wash’ of AR yeast in water to consume the asparagine on the surface of potato slices was tested before deep-frying. A short (5 to 10 minute) soak, before the potato pieces were further processed, removed approximately 70% of the asparagine (Figure 1). Most importantly, using yeast in this process did not affect the taste or other attributes of the cooked product. Any residual yeast on the outside of the potatoes was easily removed by rinsing the treated potatoes in fresh water before further processing. Increasing the surface area of potato by thinly
slicing it into pieces exposes more asparagine for the AR yeast to remove. This method is minimally disruptive to current industrial potato processing practices and maintains the quality and sensory attributes of the products.
Since the AR yeast is an industrial baker’s yeast strain, it can replace conventional baker’s yeast currently used in baking applications. Laboratory testing on white and whole wheat bread found that AR yeast consistently delivered an 80% reduction in acrylamide content (11). End-user cooking practices can significantly increase acrylamide levels. This illustrates a major concern for government regulators: while acrylamide levels can be low when foods leave the point of manufacturing, they can rise significantly when any asparagine remaining in the food is heated to high temperatures during home or restaurant cooking. Acrylamide levels in bread rise significantly after toasting. Tests showed that dark toast made from white bread leavened with conventional yeast contained up to 195 parts per billion (ppb) of acrylamide, 6.5 times more acrylamide than the same piece of untoasted bread. Similarly, dark toast made from whole wheat bread contained up to 300 ppb of acrylamide, 8.5 times more acrylamide than the bread. AR yeast was shown to reduce acrylamide in toast by 80% (Figure 2). In most cases, the acrylamide content of dark toasted bread made with AR yeast was less than that of untoasted bread made with conventional baker’s yeast.
Outlook
The new acrylamide-reducing baker’s yeast offers potential not only to reduce the health threat from acrylamide but also to Image may be NSFW. Clik here to view.help the food industry meet government regulations on acrylamide in many different food products.
4 Pedersen Metal. 2012. Birth weight, head circumference, and prenatal exposure to acrylamide from maternal diet: the European prospective mother-child study (NewGeneris). Environmental Health Perspectives. 120(12):1739-45.
7 Tareke E et al. 2002. Analysis of Acrylamide, a Carcinogen Formed in Heated Foodstuffs. Journal of Agricultural and Food Chemistry . 50: (17) 4998-5006
