The researchers from the University of Georgia in the US, with support from the Peanut Collaborative Research Support Program, looked at full and reduced fat peanut butters as a vehicle of delivery for combinations of three different probiotic species.
They found Streptococcus/Lactococcus strains survived better than the Bifidobacterium strains while full or reduced fat content did not impact the results.
The paper responded to a key question in probiotic research: How effective are orally administered products? It remains unclear how many of the bacteria can make it through the treacherous journey of the digestive system in particular past the acidity of the human stomach.
Three commercial probiotic products provided by the American Blanching Company, labelled ‘C’, ‘N’ and ‘U’, were used in the study.
'C' contained Lactobacillus rhamnosus GG. The manufacturer claimed each capsule contained 10 billion viable cells.
'N' contained five species of Bifidobacterium and nine species of Lactobacillus including Bifidobacterium bifidum, Bifidobacterium breve,Bifidobacterium lactis, B. lactis, Bifidobacterium longum, Lactobacillus acidophilus, Lactobacillus brevis, Lactobacillus bulgaricus, Lactobacillus casei,Lactobacillus gasseri, Lactobacillus paracasei, Lactobacillus plantarum, L. rhamnosus,Lactobacillus salivarius, Lactococcus lactis and Streptococcus thermophilus. The manufacturer claimed it contained 16 billion live cells per grams of powder.
'U' contained a mixture of L. acidophilus, L. acidophilus, B. bifidum and B. lactis. The manufacturer claimed it contained 50 billion live cells.
Past research suggested foods with high pH values and high “buffering capacities” could reduce the acidity of human stomach and improve the viability of probiotic cells. Probiotics could also be helped by so-called symbiotic combinations, i.e. prebiotic ingredients like inulin, fructooligosaccharides, galactooligosaccharides and lactulose.
Inoculation of the full fat and reduced fat peanut butter was at a level of 107 colony-forming units per gram.
Average bacterial populations for all three probiotic products was decreased significantly after 120 minutes in the simulated gastric phase and remained at similar levels thereafter. However, more probiotic bacteria survived in the peanut butter tests than in the 'no peanut butter' control.
“Peanut butter homogenates protected the bacteria from all three probiotic products used in this study. However, this protective effect was more obvious for probiotic strains from product U judging by the size of population difference between peanut butter homogenates and the control samples. This result suggests that ingestion with food might be necessary in order to receive expected health benefits from the probiotic bacteria from product U,” they wrote in the Swiss journal LWT.
Source: LWT - Food Science and Technology
Vol 62, Iss 2, doi:10.1016/j.lwt.2015.02.018
“Effect of peanut butter matrices on the fate of probiotics during simulated gastrointestinal passage”
Authors: Y. A. Kafui Klu, J. Chen