• Influence of chaperone-like activity of caseinomacropeptide on the gelation behaviour of whey proteins at pH 6.4 and 7.2.

      Gaspard, Sophie J.; Sharma, Prateek; Fitzgerald, Ciarán; Tobin, John T.; O’Mahony, James A.; Kelly, Alan L.; Brodkorb, Andre; Dairy Research Ireland; Teagasc Walsh Fellowship Programme; European Union; et al. (Elsevier, 2020-08-15)
      The effect of caseinomacropeptide (CMP) on the heat-induced denaturation and gelation of whey proteins (2.5–10%, w/v) at pH 6.4 and 7.2, at a whey protein:CMP ratio of 1:0.9 (w/w), was investigated using differential scanning calorimetry (DSC), oscillatory rheology (90 °C for 20 min) and confocal microscopy. Greater frequency-dependence in the presence of CMP suggested that the repulsive interactions between CMP and the whey proteins affected the network generated by the non-heated whey protein samples. At pH 6.4 or 7.2, CMP increased the temperature of denaturation of β-lactoglobulin by up to 3 °C and increased the gelation temperature by up to 7 °C. The inclusion of CMP strongly affected the structure of the heat-induced whey protein gels, resulting in a finer stranded structure at pH 6.4 and 7.2. The presence of CMP combined with a lower heating rate (2 °C/min) prevented the formation of a solid gel of whey proteins after heating for 20 min at 90 °C and at pH 7.2. These results show the potential of CMP for control of whey protein denaturation and gelation.
    • Symposium review: Genomic investigations of flavor formation by dairy microbiota

      McAuliffe, Olivia; Kilcawley, Kieran; Stefanovic, Ewelina; Teagasc Walsh Fellowship programme; Dairy Research Ireland; IRCSET; EU Marie Curie Actions Clarin Co-Fund (Elsevier, 2018-10-19)
      Flavor is one of the most important attributes of any fermented dairy product. Dairy consumers are known to be willing to experiment with different flavors; thus, many companies producing fermented dairy products have looked at culture manipulation as a tool for flavor diversification. The development of flavor is a complex process, originating from a combination of microbiological, biochemical, and technological aspects. A key driver of flavor is the enzymatic activities of the deliberately inoculated starter cultures, in addition to the environmental or “nonstarter” microbiota. The contribution of microbial metabolism to flavor development in fermented dairy products has been exploited for thousands of years, but the availability of the whole genome sequences of the bacteria and yeasts involved in the fermentation process and the possibilities now offered by next-generation sequencing and downstream “omics” technologies is stimulating a more knowledge-based approach to the selection of desirable cultures for flavor development. By linking genomic traits to phenotypic outputs, it is now possible to mine the metabolic diversity of starter cultures, analyze the metabolic routes to flavor compound formation, identify those strains with flavor-forming potential, and select them for possible commercial application. This approach also allows for the identification of species and strains not previously considered as potential flavor-formers, the blending of strains with complementary metabolic pathways, and the potential improvement of key technological characteristics in existing strains, strains that are at the core of the dairy industry. An in-depth knowledge of the metabolic pathways of individual strains and their interactions in mixed culture fermentations can allow starter blends to be custom-made to suit industry needs. Applying this knowledge to starter culture research programs is enabling research and development scientists to develop superior starters, expand flavor profiles, and potentially develop new products for future market expansion.