Final Report Summary - MILK PEPPER (Milk Powder for Enhancing Probiotic PERformance) Development of structured milk powders for enhancing probiotics delivery performanceAccording to a recent international consensus expertise, scientific relevance of the probiotic concept is now well demonstrated. Unfortunately, during the last 10 years, many food products exploiting the term probiotic without meeting some requi¬site criteria become a major issue. Consequently, the European Food Safety Authority, with an interest in protecting consumers from misleading claims decided to regulate the market. Due to this new regulation in 2012, EFSA systematically rejected probiotic applications submitted under the Nutrition and Health Claims Regulation, even though evidence for health benefits have pro¬gressed rapidly. European industries must now provide extremely robust proofs to label a probiotic health claim on the packaging of a new product. This is why pioneering research on LAB (Lactic Acid Bacteria) has mainly focused on their host effects. But, under the terms of this regulation, the viability of cultures in the functional food must be assessed too.Probiotics encapsulation is undeniably an answer to these challenges. Encapsulation has already proven an efficiency for the protection of probiotics during food processing, food conservation, gastric digestion and for the targeting of the delivery in the intestine. But there is a necessity to better understand interactions between probiotics and matrices in order to optimize the processes. Project deliverables:This proposal brings together a French researcher with a recognized track record in dairy powder “structure-function relationships”, and an internationally recognized team “Microencapsulation of food bioactives” that possesses unique research equipment facilities and all analytical tools adapted to dairy powders containing probiotics bacteria. The proposed research aims to highlight the potential of using structured dairy powders to enhance LGG performance (Figure 1). For this purpose, 4 deliverables (D) were defined:• D1: Identification of biomolecules interacting between LGG and milk proteins,• D2: Development of methodologies for LGG location in the powder and powder structure multiscale characterization,• D3: Adaptation of methodologies to follow LGG (encapsulated in variable dairy matrices) gastric resistance and intestinal delivery,• D4: Modeling and reverse engineering to establish structure/functionality links.Main achievements per deliverablesD1: Identification of biomolecules interacting between LGG and milk proteins. Among many milk proteins (caseins, bovine serum albumin, α-lactalbumin, β-lactoglobulin, mucin...) tested only two were identified as strong binders with LGG strains: β-lactoglobulin and mucin from the milk fat globule membrane. By using LGG mutants with a biophysical approach, the pili (and more particularly the glycosylated spaC units of the pili) was identified as the biomolecule interacting with these two proteins. The PI is now able to develop new optimized matrices of encapsulation containing these two proteins.D2: Development of methodologies for LGG location in the powder and powder structure multiscale characterization. Unique methodologies were successfully tested in order to characterize LGG location in the powder. For this purpose, some techniques of microscopy (SEM, TEM) were implemented in addition to fixation methods (for powders and probiotics). This part was totally managed at the CMM (Center for Microscopy and Microanalysis) at the University of Queensland. Thanks to these original methodologies the influence of matrix composition and LGG surface composition on LGG release were efficaciously investigated in deliverable 3.D3: Adaptation of methodologies to follow LGG (encapsulated in variable dairy matrices) gastric resistance and intestinal delivery. In this deliverable, an optimal matrix was identified containing 80 % of casein in order to present a strong network able to resist during storage and gastric conditions. In addition, 20 % of whey proteins (containing β-lactoglobulin) were added in this optimal matrix in order to present the best encapsulation properties: thanks to the affinity between LGG (pili) and the milk protein.D4: Modeling and reverse engineering to establish structure/functionality links. In this deliverable an original process of encapsulation was developed. LGG was encapsulated by spray-drying in milk water-insoluble matrices upon reconstitution in hot water by exploiting and controlling the clotting reaction of milk proteins during the process. The process led to matrices presenting innovative functionalities when microparticles are reconstituted with water: rehydration or dispersion in cold (8 °C) or warm (40 °C) water, respectively. final1-wp-gaiani.jpg
