Messa a punto di un gelato artigianale contenente microrganismi probiotici

After several studies have proved the benefits deriving from the ingestion of probiotic bacteria, various dairy products containing lactobacilli and bifidobacteria cultures have been formulated in recent years. A 24 full factorial experimental design was applied to verify the effects of Lactobacillus johnsonii La1 and Lactobacillus rhamnosus GG addition in retail-manufactured ice cream stored at two different freezing temperatures and containing two different levels of sugar and fat. Both fresh and frozen-thawed La1 and LGG cells underwent preliminary resistance tests to acidity, bile, antibiotics, and SDS. Both the strains proved to be highly resistant to most of stress factors, thus excluding the possibility to find evidence of cell sublethal injuries caused by freezing. When the microorganisms were added to ice cream mixes in the quantity of 107-108 cfu/g, they did not modify the overrun and firmness of the finished products. Regardless of formulation, no count decay of the two strains were observed in ice cream stored for up to 1 year.