Super muffins? Research adds health benefits with hibiscus extract

08 Mar 2023 --- Researchers developed a muffin recipe containing an optimal concentration of Roselle calyx extract from the husks of Hibiscus sabdariffa. Dubbed the Roselle muffin, a panel positively tested the product’s taste and texture. The muffin contained high levels of antioxidants, anthocyanin, phenolic and ascorbic acid, which the researchers note are linked to various health benefits.

NutritionInsight sits down with the study’s authors, Eva Falch, associate professor in food science at the Norwegian University of Science and Technology, and Nutan Kaushik, professor at the Amity University Uttar Pradesh in India. 

“We hope that this study will widen the use of natural ingredients in food for health, taste, and preservation purposes,” notes Falch. 

“At the same time, this study increases the knowledge about underutilized food resources that can be upgraded as future food ingredients, thereby contributing to food and nutritional security. Many of our global future food sources are scarce and as researchers, I think we need to engage also in the formulation of new healthy products.” 

The authors note that the study’s outcomes can be utilized to develop foods containing Roselle calyx extract. 

The study is part of Re-FOOD, a Norwegian-Indian collaborative project that focuses on using and enhancing the value of the left-over raw materials from food processing. The results have been published in Foods. The researchers created a muffin containing Roselle calyx extract that had nutritional benefits. 

Commercial applications 
Falch explains that business development is needed to upgrade Roselle extracts into food ingredients, as these are not commercially available. 

“One way of marketing the product’s health benefits is using health and nutrition claims on the front-of-pack label. Different authorities regulate these depending on the targeted market and what scientific substantiation is needed.” 

Kaushik suggests that food manufacturers target health-conscious consumers with the product. “The plus point is that the product contains no artificial ingredients.”  

The Roselle muffin has a shelf life of six days without preservatives.

Health benefits 
Roselle calyx extract contains bioactive compounds, such as polyphenols, flavonoids, betaine and hibiscus acid. 

However, the researchers note that antioxidant properties decreased after baking. The muffin batter had an antioxidant activity of 27.3%, while that of the baked Roselle muffin was 12.53%. 

“Roselle extracts also contain compounds that are important in a healthy diet, such as the cocktail of antioxidants that need to be further explored in some markets to use health claims,” adds Falch.  

“As an ingredient, the Roselle calyx extract can provide different positive properties to a product such as bioactive, natural preservation and natural color.”

Optimizing muffin mix  
The product was developed using different formulations in varying proportions resulting from Response Surface Methodology that predicted formulations with the most favorable outcomes. The researchers replaced milk in vanilla muffins with varying concentrations of roselle extract and added different citric acid and sodium bicarbonate levels. 

Thirty people tested the resulting 17 recipes. The optimal mix contained 45.37 ml of the extract volume, 1.11 grams of citric acid and 1.16 grams of sodium bicarbonate, which scored 8.31 for texture and 8.30 for overall acceptability. 

The researchers measured the participants’ responses to the muffins’ color, appearance, aroma, texture, fluffiness, elasticity, freshness and chewing resistance. Roselle calyx extract contains bioactive compounds, such as antioxidants, flavonoids, betaine and hibiscus acid. 

Compared to a control muffin, the optimized Roselle muffin had higher acceptability scores for body, texture, taste and flavor. However, some taste panelists noted the muffin had a slightly sour taste. 

Follow-up research 
Falch notes that the study has demonstrated a method to scientifically optimize the functional and sensory properties of a new ingredient in a product, with muffins as a model product. “The nutritional composition of the muffin recipe can be improved by reducing the sugar and fat content.”

The authors conclude that the ingredient should be tested in products with a better nutritional profile, such as whole grain products. 

“A follow-up in this study will be to test the extract in different food systems and nutritionally optimized foods such as a Roselle muffin with minimal sugar, salt and saturated fat and maybe also more fibers,” adds Falch. “It can then become a natural daily food choice replacing supplements.” 

“Another follow-up will be to document further the health benefits of the Roselle calyx extract and the effect in the food product used.” 

By Jolanda van Hal