Stevia added to kale juice spheres during 7 days refrigerated storage
What it found
Adding stevia to kale juice spheres improved their taste without changing their quality over 7 days in the fridge.
The work was done on food products, not in people or animals.
What they found
Studies in people
Taste scores improved
A trained panel of eight people rated the flavour of plain kale spheres lowest. Adding stevia smoothed out the bitter taste, and the two highest stevia amounts earned top flavour scores of about 5 out of 5.
Other findings
Colour stayed greener
All spheres lost some green colour over the 7 days. The batch with the most stevia, 2.5 g per litre, showed the smallest colour change after a week in the fridge.
Microbe levels stayed low
Bacteria and yeast counts rose slightly during storage in all batches. Every sample stayed below 7 log CFU per gram after 7 days, no matter how much stevia was used.
Sulforaphane levels unchanged
Sulforaphane is a plant compound found in kale. Its amount did not differ between the plain spheres and those sweetened with stevia across the full 7 days.
Firmness held steady
The spheres kept their shape and size throughout storage. The batch with the most stevia had the smallest changes in firmness over the week.
What the authors conclude
- They say that sweetening kale juice with stevia is a good way to reduce its strong bitter taste and encourage more people to consume it.
- Their tests showed that the double spherification method produced sturdy spheres that kept good physical and sensory quality for 7 days at 5 °C.
- They note that adding stevia did not lower the sulforaphane content of the kale spheres during refrigerated storage.
How it was done
Kale contains many useful plant compounds but tastes very bitter, so few people drink it as a beverage. The authors wanted to see if adding stevia could mask that bitterness while keeping the product stable.
The researchers made small gel spheres out of kale juice and added different amounts of stevia extract, including a batch with none. They stored the spheres at 5 °C for 7 days and measured colour, firmness, microbes, taste scores from eight people, and plant compounds.
What it can’t tell you
- This work tested food products in a lab, not health effects in people or animals.
- It cannot show whether eating these kale spheres changes anything inside the human body.
Who paid
- Funding
- Funded by Conselho Nacional de Desenvolvimento Científico e Tecnológico; Sacoje SCL; Sakata Seeds Ibérica SLU (from the PubMed record).
- Authors work at
- Institute of Plant Biotechnology, Spain
The paper
- Title
- Effect of stevia supplementation of kale juice spheres on their quality changes during refrigerated shelf life
- Type
- Study
- Evidence
- Studies in people
- Summarised from
- Full text
- Cite
- Klug TV, Collado E, Martínez-Hernández GB, Artés F, Artés-Hernández F (2019). Effect of stevia supplementation of kale juice spheres on their quality changes during refrigerated shelf life. Journal of the science of food and agriculture. doi:10.1002/jsfa.9445Free full textPubMed 30357844DOI
Summary written 30 Sep 2026. Check it against the paper before it changes what you eat. How we summarise papers · Report an error