In an effort to find natural ways to keep pastry dough from turning brown over time, scientists discover what many grandmothers already knew: add lemon – but, with a twist.
A new study shows that white wine and lemon juice together is the most effective, natural way to prevent enzymatic browning in dough without using artificial additives or special flour.
“Dough discolouration is attributed to several subsequent enzyme-substrate reactions, which can selectively be inhibited by food additives,” writes the research team, led by Linda Brütsch of the Institute of Food Nutrition and Health in Zurich, Switzerland.
However, many customers don’t like seeing a list of artificial ingredients on packaging. Yet for pastry-making companies finding ways to stop their raw product discolouring is essential.
“Despite their effectiveness, the unlimited use of commercial inhibitors is nondesirable due to necessary labelling, thus sustainable and natural inhibitors usually occurring as conventional food ingredients are of interest,” Brütsch’s team write in the American Chemical Society’s Journal of Agricultural and Food Chemistry.
One way to prevent browning has been to use “extra white” flour, known as type 380, which is made with only the inner portion of wheat endosperm. The flour contains less polyphenol oxidase (PPO), the molecule responsible for browning in everything from apples to tobacco, but it is more difficult and costly to produce than standard white flour, known as type 550.
“Browning in food products is generally related to loss of cell integrity caused by mechanical or thermal processes,”the researchers explain.
“This results in the disruption of membranes, cell walls, and other cellular structures enabling interaction of enzyme and its substrate. In the presence of oxygen, PPO is then capable of catalysing melanin formation, which is the coloured metabolic end product of enzymatic browning.”
To avoid this unsightly process – and avoid using additives – the researchers tested lemon juice, grape juice, and white wine in various combinations on type 550 flour. Over four weeks, a quartet of trials produced a lighter coloured product than plain type 550 flour. However, but the combination of wine and lemon together was the most effective.
Dough made using standard flour, but with white wine and lemon juice added, “showed minimum discolouration” and was similar in appearance to dough made with type 380 flour, the researchers found.
“Lemon juice demonstrated the highest inhibitory potential while white wine revealed itself as ideal additive for prevention of enzymatic browning and mold formation,” they conclude.
Swiss baked goods maker Jowa AG and Swiss Food Research, an industry association, backed the study.
Samantha Page is a science journalist based in Spain.
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