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A panel of 30 people tested a total of 17 recipe variants in the muffin study. The aim was to find the best version of Roselle muffins in relation to three important qualities: taste, nutrition and shelf life.

Developing muffins that could be good for your health

Imagine sinking your teeth into a tender muffin that tastes good and is chock full of vitamins, antioxidants and other natural ingredients that are good for your health, too.

Communication adviser
Presented by: NTNU - Norwegian University of Science and Technology
Published

We’re talking about a tasty, fluffy muffin that has no artificial additives and that simultaneously contains lots of beneficial nutrients.

As remarkable as it might sound, a recently published study describes the development of just such a new muffin in the journal Foods.

From muffins to functional food

The new super muffin has been named Roselle, because it contains calyx extract from the tropical plant Hibiscus sabdariffa, which is often referred to by the same name.

Hibiscus flowers have a beautiful red colour, and the calyx extract contains many valuable bioactive compounds, such as polyphenols, flavonoids, betaine and hibiscus acid. All of these components can be used to develop new products and functional food that may offer positive health effects, possibly also reducing the risk of chronic diseases.

The study also shows that Roselle muffins maintain their freshness for up to six days at room temperature, but with so many beneficial qualities, chances are they will be long gone by then.

Health benefits

The study is part of Re-FOOD, a Norwegian-Indian collaborative project focusing on using and enhancing the value of rest raw materials of food processing.

Professor Nutan Kaushik at Amity University in the state of Uttar Pradesh, India, points out the health benefits of antioxidants, especially when it comes to neutralising free radicals, which can be an important contributing factor to serious illnesses.

Roselle is also rich in anthocyanins. This is a dye that can be dissolved in water and yields a red, pink, purple, blue, blue violet or violet colour. The colour of food has a strong influence on how appetising we think it is.

Artificial dyes are often clearer and more intense than natural substances. But the demand for natural dyes is increasing because of the concern that artificial dyes are harmful to our health.

Tasty, nutritional and long shelf-life

In the muffin study, 30 people tested a total of 17 recipe variants.

The aim was to find the best version of Roselle muffins relative to three important qualities:

  • The muffin should have a taste and texture that people like.
  • The muffin should have valuable nutritional properties.
  • The muffin should have the best possible shelf life without preservatives.
Here’s a look at the different formulations that researchers tested.

Natural food colouring — good for our cells

The researchers measured and surveyed the test subjects’ response to the pastry’s colour, appearance, aroma, texture, fluffiness, elasticity, freshness and chewing resistance.

They used the Response Surface Methodology to model and analyse how the test subjects’ reactions were affected by various factors.

The aim of this method is to achieve the most positive response to what is tested.

In terms of nutrition, the results suggest that the hibiscus extract provides muffins with high levels of antioxidants like phenolics.

These are substances believed to be able to prevent processes in the body that can damage cell membranes or the genetic material in our cells. There are several thousand different phenols, most of which are found in fruit, juice, wine, cocoa, tea, coffee, vegetables, flax seed, whole grains and legumes.

Hibiscus sabdariffa is frequently used in teas and juices.

Maybe not so healthy

The Roselle calyx extract obviously provides health benefits, but this research is primarily good news for those of us who already eat muffins.

Eva Falch is an associate professor at NTNU’s Department of Biotechnology and Food Science, and a co-author on the study. She doubts that Roselle would be able to be classified as healthy in Norway.

“Roselle calyx extract is an underutilised resource, and the study primarily shows the potential of the plant extract. The researchers use the muffin as a model to say something about how ingredients and steps in the manufacturing process affect and change the properties of the final product,” Falch says.

Classifications and health recommendations, as well as taste and food culture, vary between countries.

“In food cultures where baked goods like this are part of the daily diet, Roselle muffins can contribute to increased nutritional value. To make a healthy version, the whole composition should be as good as possible, with little sugar, salt, saturated fat, and so on,” Falch says.

Animal models

A next step could be to test this ingredient in products with a better nutritional profile, such as whole grain products, so that it can be part of a healthy diet.

Professor Nutan Kaushik says the findings have helped in getting the acceptance among consumers as well as regulators.

“Next, we plan to do study the health benefits on animal models and launch a start-up company,” she says.

Shelf life and mould spores

Shelf life was the third factor the researchers investigated. When dry and semi-dry baked goods such as biscuits are left for too long, they can deterioriate both physically and chemically.

Muffins with a higher moisture content, on the other hand, are more vulnerable to bacteria, fermentation and mould.

Mould and mould spores are destroyed by heat during baking, but as soon as the muffins are out of the oven, they are exposed to airborne mould spores.

Roselle muffins have no added preservatives. The beauty is that the antioxidant ascorbic acid is also found in the pastry. This is a chemical bond that can contribute to increased shelf life in food products.

And when it comes to the effects of ascorbic acid on the human body, most of us know it by its common name, vitamin C. The tests showed that Roselle kept well for six days at room temperature, with no signs of mould or spores.

The muffin study

  • Title: ‘Nutritionally Enriched Muffins from Roselle Calyx Extract Using Response Surface Methodology’.
  • The control muffins were based on a standard vanilla muffin recipe.
  • All ingredients were bought locally, and the taste panel had 30 test subjects.
  • Compared to the control muffin, Roselle received the highest overall acceptability score (8.3).
  • An average score of 7 or more on a nine-point scale approaches what the researchers call an "extremely acceptable sensory quality."
  • Products that achieve such a high score will be close to the quality that food manufacturers want to offer.
  • Compared to the control muffin, the protein and fat content of the Roselle muffin was significantly lower. The carbohydrate content was very similar.
  • The ascorbic acid content was 12.1 mg/100 g. The recommended daily dose for adults is 75 mg for women and 90 mg for men.

Reference:

Marak et al. Nutritionally Enriched Muffins from Roselle Calyx Extract Using Response Surface Methodology, Foods, vol. 11, 2022. DOI: 10.3390/foods11243982

Re-Food (2017-2020)

  • The muffin-study is part of the Re-FOOD project, and INTPART-ptoject funded by the Research Council of Norway.
  • INTPART is an abbreviation for International Partnerships for Excellent Education, Research and Innovation
  • The project builds collaboration between Norwegian and Indian research, education and innovation.
  • The aim is to achieve the highest possible utilisation of resources in the food value chain.
  • RE-FOOD also focuses on the importance of natural plant extracts for colour, durability and health effects in the food of the future.

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