New product idea? Study used chia and flaxseeds to encapsulate probiotics
“These ternary blends protected the probiotics and enhanced their resistance to simulated gastric juice and bile solution,” the researchers wrote in their study, published online in Food Chemistry.
Their findings come at a time when demand for probiotics is at a high, €32bn according to Euromonitor, and projected to reach €43.5bn in 2020—accounting for supplements (but not combination supplements), yogurts, and juice.
According to the researchers, their aim was to evaluate “the feasibility to increase B. infantis ATCC 15679 and L. plantarum ATCC 8014 survival after spray drying using mucilage and soluble protein fractions from chia seeds or flaxseed as encapsulating materials.”
Preparing the flaxseeds, chia, and probiotic strains
The researchers used probiotic strains B. infantis ATC 15679 and L. plantarum ATCC 8014 from American Type Culture Collection. Flaxseed and chia seeds were purchased from the local market in Chile.
Flaxseed and chia seed mucilage was extracted and then spread on a tray and dried in an air convection heat oven. Seeds that were mucilage-free were defatted with hexane twice and turned into flour, stored at a low temperature to extract soluble protein. Bacteria used in the study were sub-cultured twice. The cells for the spray drying assays were grown in 400 ml of Lactobacili broth and incubated, and afterwards were re-suspended in sterile distilled water.
Then, the soluble protein from the two seeds were dispersed in distilled water and heated to allow denaturation and aggregation. The probiotic cells suspended in sterile distilled water were added with sterile encapsulating solutions in various compositions, which included a blend of the two seeds with other chemicals (such as maltodextrin), or an encapsulation solution made of the mucilage and soluble protein of just one seed type.
Measuring probiotic survival
Bacterial suspensions with total viable counts between 108 and 109 CFU/ml were continuously mixed using a magnetic stirrer during the spray drying process, done in a laboratory spray dryer with a 1.5 mm diameter nozzle, a spray chamber, and a peristaltic pump.
The resulting powder was collected in sterile glass bottles, cooled using an ice bath and stored at a low temperature until characterization. The survival after this process and viability of encapsulated bacteria was followed for 45 days using the plate count method and analyzing colony forming units per gram. Additionally, the researchers looked at the survival of encapsulated probiotics in simulated gastric juice and bile conditions.
To see how the resulting powders can be used as a functional consumer good, the researchers mixed the dry powders with an instant juice powder obtained from the local market seven days after spray drying. The ratio of the mixture was two parts juice, one part bacterial powder (with 30 g serving per pack).
So did they survive?
“The variance in probiotic survival and viability was predominantly associated with the composition of the encapsulating agent accounting for over 78% of the total variation on the first day of storage viability,” the report said.
They found that encapsulating probiotics for human consumption was most effective when done with a ternary blend of maltodextrin, mucilage, and protein.
B. infantis encapsulated in maltodextrin, flaxseed mucilage, and flaxseed soluble protein exhibited enhanced resistance to the action of bile salts and simulated gastric juice. The encapsulation solution maltodextrin, chia seed mucilage, and chia seed soluble protein showed similar behavior.
Mixed in an instant juice powder, the researchers found that probiotics encapsulated in a ternary blend performed better than those in just maltodextrin, “attaining 10.5–11 Log CFU/g after 45 days storage,” the researchers observed.
“This indicates the effective film forming and emulsion stabilization properties of the mucilage (particularly from chia seed) and the protein stabilizing/protective effects of the probiotic microcapsules during juice powder storage,” they wrote, adding that the mechanism through which the seed fractions confer protection during spray drying still needs to be researched.
Source: Food Chemistry
Published online ahead of print, http://dx.doi.org/10.1016/j.foodchem.2016.08.019
Authors: Mariela Bustamante, B. Dave Oomah, Mónica Rubilar, Carolina Shene
