Mustard seed a possible new food preservative

A University of Alberta student has discovered a compound derived from a mustard seed that could potentially be used as a natural food preservative.

Christina Engels, a doctoral student in the Department of Agricultural, Food and Nutritional Sciences, has found that sinapic acid, a natural compound that comes from oil meal — the leftovers of pressed mustard seed oil — has antimicrobial properties against a variety of food pathogens and food spoilage bacteria.

As a result, sinapic acid is able to limit the growth of many microorganisms. 

Mustard oil is commonly used for cooking, but it can also be converted into biodiesel, a renewable source of fuel.

However, Engels focused on finding a method that would make it easy to extract sinapic acid from the oil meal.

“Normally, when we extract plants, we get an extract that has many compounds it in, and it’s very hard to find what the active component actually is and then find a method to quantify it,” Engels said.

“The cool thing in the method that I proposed … is a process called alkaline hydrolysis, which was able to selectively extract sinapic acid.” 

Engels centred her research on the by-product of mustard seed oil — the oil meal. By only using the oil meal instead of other parts of the plant that are intended for human consumption, Engels was able to extract sinapic acid in the most sustainable way possible.

Engels hopes her method of extraction will one day be used by industry to make sinapic acid a natural preservative in food products because of its natural antimicrobial properties.

“The ultimate goal is to use natural components that work as preservatives, and not to use synthetic ones,” Engels said.

Engels will be defending her PhD in May, and plans to continue working on ways to extract natural antimicrobial compounds from plant or fruit sources.

“I really believe that in plants there are activities that we are looking for in food applications — for example, antimicrobial or anti-oxidant activities. But it’s really hard to link it to one substance, and it is really not known which component is active,” Engels said.

“I’m hoping that we can find methods, so that we can really scientifically link that one component to the activity and there is no doubt about it.”

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