Maintaining flavour while ensuring the safety of processed vegetables

It’s generally accepted that heating vegetables before freezing or canning them – using a process called blanching – will affect their taste and texture. And yet heat treatment is considered necessary to ensure food products are safe for human consumption.

But what if certain vegetables that are really fragile to blanching actually don’t require the same heat treatment intensity in order to ensure food safety?

Do the enzymes in the produce responsible for the taste deterioration after blanching cause that same change in flavour when less heat or even no heat treatment at all is used – or if the vegetables are partially dehydrated instead?

That’s what technical and product development staff at Bonduelle North America and researchers Tony Savard and Lamia L’Hocine from Agriculture and Agri-Food Canada’s Food Research Development Centre (FRDC) in St-Hyacinthe, are trying to determine.

“We want to find a way to process vegetables as close to fresh as possible for food service and retail,” explains Michel Casgrain, Corporate Director of Research and Development at Bonduelle. “If we are successful, it opens the door to expanded production and processing of vegetables, especially those
that are very fragile to heat treatment.”

The research involves monitoring the development of undesirable flavours based on the enzyme levels in various vegetables and determining whether conventional blanching is even needed in vegetables like onions or peppers, which are particularly affected by that process.

To date, no single enzyme has been found across all vegetables as the cause for the change in taste. A literature review has identified a few that seem to be leading candidates, and researchers at FRDC are working to validate these findings.

Over 500 pounds each of peppers, zucchini, mushrooms and onions have been assessed and tested so far, with some undergoing reduced blanching treatments and others being partially dehydrated instead. Initial sensory analysis has shown positive results in peppers and zucchini four months after processing, but the results have not been as successful for onions or mushrooms.

For example, partially dehydrated zucchini as well as those treated with a reduced blanching regimen showed increased crunch and sweetness when compared to those that went through a traditional blanching treatment. Partially dried red peppers were also found to be crunchier and sweeter than conventionally treated ones.

Although this is a positive initial outcome, researchers say more time is needed to determine how the partial dehydration will impact shelf life over the longer term, and whether any links exist between enzyme levels, flavour, and taste. Moreover, the safety of those reduced thermal treatments hasn’t yet been tested, and challenge tests are planned to evaluate food safety.

During the second year of the project, FRDC researchers will also be applying protocols they’ve developed to measure the impact of reduced blanching on the quality and safety of the processed vegetables and analysing the results.

It is estimated that if the technology is successful, a move away from conventional blanching methods will improve food quality without compromising safety, lower processing times, reduce processing costs, and open new product and market opportunities for vegetable and fruit processors.

Why is this innovation important?

Food safety: This will ensure vegetables processed using these new technologies will meet existing rigorous standards for food quality and safety.
Health: An overall improvement in the quality of frozen vegetables could lead to increased access and consumption, which will have positive health impacts on Canadians.
Markets: This technology could open new markets for frozen vegetable products and reduce food waste.

What does this innovation mean to Canada’s food processing industry?

Project outcomes, if successful, will open the doors to expanded production and processing of vegetables, especially those that are very sensitive to current blanching processes, and provide superior quality and nutrition.

About Bonduelle Group

The French family-run Bonduelle Group is one of the largest fruit and vegetable processors in the world with markets in over 100 countries and more than 50 processing facilities worldwide. Bonduelle’s Canadian presence includes offices in Quebec and Ontario, and four processing plants in Quebec, three in Ontario, and one in Alberta, where they make product for national and private label brands such as President’s Choice, Selection, Irresistible, Green Giant, and Arctic Garden.

About the project team

Dr. Tony Savard is a research scientist in food microbiology with Agriculture and Agri-Food Canada’s Food  Research Development Centre in St-Hyacinthe. He holds a BSc and a PhD in Microbiology and an MSc in Neurophysiology, all from Université de Sherbrooke.

Dr. Lamia L’Hocine has been a research scientist at Agriculture and Agri-Food Canada’s Food Research Development Centre in St-Hyacinthe since 2008. She completed a Bachelor’s Degree in food science at the Algerian National Agronomy Institute, and an MSc and PhD in food science and technology at Jiangnan University in China.

Cluster 1 2015-2018


Enhancing quality


Analysis of reduction of blanching and enzymatic effects on the generated flavour profiles of certain vegetables

Industry partner

Bonduelle North America, Saint-Denis-sur-Richelieu QC

Principal investigator

Dr. Tony Savard*, Food Microbiologist, Agriculture and Agri-Food Canada, St-Hyacinthe QC


Dr. Lamia L’Hocine*, Research Scientist, Agriculture and Agri-Food Canada, St-Hyacinthe QC

Cindy Ricard, Canneberge ATOKA, Manseau QC

Anticipated completion date

31 March 2016