Heatwaves & Health: Can Ice Cream Serve as an Effective Vehicle for Probiotics?

As summer temperatures rise and heatwaves become an increasingly familiar part of the season, staying refreshed is always a priority. Traditionally enjoyed as a cooling treat, ice cream is now gaining attention for another potential role: serving as a vehicle to deliver probiotics to the human body.

A recent study has investigated the effects of probiotic, passion fruit peel–extracted pectin (PFPEP) and synbiotic ice cream (PFPEP and probiotics) on probiotic survival, microbiota composition and metabolite production. A synbiotic is the combination of a probiotic organism with specific substrate(s) that promote growth of the organism.

PFPEP has shown potential as an effective prebiotic ingredient in dairy products and can modulate gut microbial composition as well as enhance short-chain fatty acid (SCFA) production. The probiotic strains chosen for this study were Lactobacillus acidophilus DSM20079, L. rhamnosus GG, and Bifidobacterium animalis subsp. lactis BB-12 and they were separately cultured in a Whitley Anaerobic Workstation under 80% (v/v) N₂, 10% (v/v) CO₂ and 10% H₂ atmosphere for 16 hours. Four ice cream formulations were prepared – these were control ice cream (without PFPEP or probiotics), probiotic ice cream, prebiotic ice cream (with PFPEP) and ice cream with both PFPEP and probiotics. Where applicable, each probiotic mixture was added at a final concentration of 8 log₁₀ CFU/ml of ice cream. An in vitro digestion system was created using materials to simulate the digestion process; after in vitro digestion was complete, probiotic viability was determined using spread plates that were then incubated anaerobically. There was a significant reduction in viable cell counts for probiotic and synbiotic treatment, highlighting the effect of acidic pH and bile salts on bacterial survival. The synbiotic ice cream had a significantly higher value of viability at 8.23 ± 0.02 log₁₀ CFU/ ml compared to 8.01 ± 0.01 log₁₀ CFU/ml for the probiotic ice cream. This suggests PFPEP supplementation may provide microencapsulation-like effects which helps probiotic viability as well as boosting bacterial tolerance to digestive stresses.

To evaluate the effect of the different ice cream preparations, independent faecal batch culture fermentations were carried out. Faecal samples taken from healthy volunteers were homogenised and used to inoculate carbohydrate-free basal medium tubes. These were incubated anaerobically and after incubation, time-point analysis was carried out. With regards to pH, a significant decrease was observed in all faecal cultures with pH dropping from 6.3 to 4.6 within the first 5 hours of fermentation. This rapid decline suggests active microbial fermentation and organic acid production occurred. Regardless of ice cream formulation, acidification was constant across all treatments. The prebiotic ice cream demonstrated a lower pH compared to other formulations, which is likely due to pectin and its ability to influence to mild acidification during fermentation. Despite containing the same concentration of pectin, the synbiotic ice cream maintained a higher pH, which could be explained by metabolic interactions between probiotics and the gut microbiota.

The composition of faecal cultures was also analysed: the benchmark composition of the faecal samples showed Fusobacterium, Escherichia-Shigella and Bacteroides to be the most abundant. The probiotic and synergistic ice creams showed a significantly higher quantity of Lacticaseibacillus and B. animalis. During fermentation, they observed a significant decrease in alpha-diversity in all faecal cultures suggesting the supplementation of each ice cream formulation altered microbiota diversity and composition. All ice cream formulations reduced the abundances of Escherichia–Shigella, Fusobacterium, and Dorea.

SCFAs were analysed by gas chromatography to quantify compounds such as acetate, propionate and butyrate in the faecal culture supernatants.  Acetate, propionate and total SCFA concentrations significantly increased during fermentation across all ice cream formulations, suggesting that the faecal microbial composition remained metabolically active during fermentation. This ability to modulate SCFA production is beneficial to human health in terms of controlling blood pressure and advances in glucose and lipid metabolism but is dependent on the availability of fermentable substrates and components of the microbial community.

Successful delivery of probiotics into the body is of paramount importance, and using a simulated gastrointestinal digestive model, this study shows ice cream can be an effective vehicle in distributing probiotics such as L. acidophilus DSM20079, L. rhamnosus GG, and B. animalis subsp. lactis BB-12, when supplied alone or in combination with a prebiotic. Different ice cream formulations promoted beneficial bacterial groups, whilst also reducing pathogenic bacteria. An arguable key factor in this study was PFPEP, and the encouraging results produced suggest it could be a potential functional ingredient for dairy product development.

Written by DWS Microbiologist Kirsty McTear

All information attained from:

Pimisa R, Arboleya S, Rey-Mariño A, Hwanhlem N, Gueimonde M. In vitro simulated digestion and fermentation of synbiotic ice-cream supplemented with passion fruit peel–extracted pectin and probiotic strains: effects on probiotic viability, microbiota composition, and metabolic activity. Food Research International . 2026 June 29;242.

Frequently Asked Questions:

What is the difference between a probiotic and a prebiotic?

Probiotics are live microorganisms that depending on dose, can elicit a beneficial impact on the host – for example, yogurt drinks that contain Lactobacilli casei. Prebiotics refer to the non-digestible substrates that can be used by microorganisms – for example, fructo-oligosaccharides. Prebiotics can be referred to as ‘food’ for probiotics.

What are short-chain fatty acids (SCFAs)?

SCFAs are metabolites of microbial fermentation; they are particularly made in the gut. Examples of SCFAs include acetate, butyrate, and propionate.

Why is a suitable vehicle necessary to deliver probiotics to the body?

Vehicles that can tolerate the harsh environment of the gut are necessary in delivering probiotics to the body. The low pH of stomach acid and presence of bile salts and digestive enzymes can damage and even kill bacteria in the probiotics, meaning there would be fewer viable bacteria reaching the gut compared to if a protective vehicle was used.