Development and Evaluation of Caseins/Caseinates for use as Ingredients in Food Products
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CitationMehra, R., Walsh, D., O'Kennedy, B., Kelly, P., Development and Evaluation of Caseins/Caseinates for use as Ingredients in Food Products, End of Project Reports, Teagasc, 1998.
AbstractThe overall objective of this project was to investigate the effects of key processing steps in the industrial production of acid casein on the characteristics and functionality of sodium caseinate with particular emphasis on analytical/functionality testing and seasonal/lactational effects on the original milk. The main conclusions were as follows: The most significant result indicates that drying and concentration after washing of the acid casein curd are responsible for alterations in the structure of casein, which result in sodium caseinates with different properties. This was confirmed in the case of two acid casein plants investigated which showed similar results even though using different washing and drying technologies. This difference due to the drying step may be further amplified depending upon whether commercial sodium caseinate is manufactured from acid casein in the dried or wet curd state. The analytical and functional testing methodology adapted in our laboratory proved effective in predicting the effects of processing steps on the functionality of sodium caseinate. In particular, the ability to detect the presence of aggregate formation was particularly important. The database generated subsequently helped an acid casein manufacturer in modifying its process(es) to manufacture experimental sodium caseinate for specific food end-uses. Progress was greatly facilitated by the collaboration of individual manufacturers in the sourcing of problem samples from previously manufactured codes, and facilitating access to process plant during production. In a commercial application of the database, confidential work was undertaken on behalf of a client. Experimentally-produced sodium caseinate ingredients were evaluated using our adapted functionality testing methods and based on the results, the company was able to modify its process(es) to produce sodium caseinates with functionality for specific food end-users. It was concluded that while processing parameters in the production of acid casein can have a significant effect on the functional behaviour of the resultant sodium caseinate, the ability to assess this change in functional behaviour, through relevant functional testing, was equally important.
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Novel Milk Protein Ingredients.Kelly, Philip; O'Kennedy, Brendan; Cribbin, M. (Teagasc, 2001-05-01)The manufacture of casein/caseinates containing whey protein is immediately attractive due to its potential to enhance product yield. However, some technologies capable of producing these products are ineligible for manufacturing subsidy because of restrictions pertaining to relevant EU regulations. Other emerging technologies require refinement and process design before implementation at industrial level. Furthermore, the implications of incorporating virtually the entire complement of whey protein in what is essentially a caseinate ingredient needs to be investigated carefully in terms of the versatility of use in a wide range of food formulations. The development is significant in the context of U.S. market changes - traditionally, an important outlet for Irish casein exports amounting to 20,000 - 27,000 t per annum. Ireland accounts for ~ 30% of EU casein/caseinate production with the greater proportion in Rennet form (27,000 t) and the remainder (18,000 t) as Acid casein. In recent years, a new market for a related casein ingredient - milk protein concentrate (MPC) opened up in the US, and accounted for total imports of 40,000 t in 1998, 10,000 t of which were exported from Ireland. However, this market is more restricted due to regulatory changes introduced in response to the perceived threat of MPC imports to the US dairy industry. Since casein, or its derivative products such as milk proteinate (EU Annex III compliant), are not perceived to be in competition with local milk supplies and dairy ingredients, it is now hoped that Irish casein manufacturers may be able to reclaim recently lost markets through the introduction of an innovative proteinate ingredient which is expected to command a premium in nutrition applications e.g. in sports, infant formula and nutraceutical products. With a choice of emerging new technologies for the production of novel casein-related ingredients, the dairy industry has an opportunity to decide on what is appropriate for the defence of its market share and at the same time benefit from simultaneous compliance with relevant regulatory supports (EU) and market access rules (USA). Hence the main aims of this project were: * To investigate new technologies for the isolation of casein and casein/whey protein combinations in the course of developing new milk protein ingredients, and * To compare the performance in selected food formulations of novel milk protein ingredients namely milk proteinates, milk protein concentrates, native phosphocasein and classical Annex III casein products.
A note on the evaluation of a beta-casein variant in bovine breeds by allele-specific PCR and relevance to β-casomorphinKeating, A.F.; Smith, T.J.; Ross, R Paul; Cairns, M.T. (Teagasc, Oak Park, Carlow, Ireland, 2008)Two genetic variants of the bovine β-casein gene (A1 and B) encode a histidine residue at codon 67, resulting in potential liberation of a bioactive peptide, β-casomorphin, upon digestion. An allele-specific PCR (AS-PCR) was evaluated to distinguish between the β-casomorphin-releasing variants (A1 and B) and the non-releasing variants. AS-PCR successfully distinguished β-casein variants in 41 of 42 animals as confirmed by sequence analysis. Overall, while the incidence of the homozygous A1 and B animals (i.e., homozygous for the histidine residue; 21.4%) was lower than that for animals without the histidine residue (30.9% respectively), 69% of animals carried at least one allele for the histidine residue at codon 67.
Effects of depleting ionic strength on 31P nuclear magnetic resonance spectra of micellar casein during membrane separation and diafiltration of skim milkBoiani, Mattia; McLoughlin, Padraig; Auty, Mark; Fitzgerald, Richard J.; Kelly, Philip; Irish Department of Agriculture Food Institution Research Measure; Teagasc Walsh Fellowship Programme (Elsevier, 2017-07-06)Membrane separation processes used in the concentration and isolation of micellar casein-based milk proteins from skim milk rely on extensive permeation of its soluble serum constituents, especially lactose and minerals. Whereas extensive literature exists on how these processes influence the gross composition of milk proteins, we have little understanding of the effects of such ionic depletion on the core structural unit of micellar casein [i.e., the casein phosphate nanocluster (CPN)]. The 31P nuclear magnetic resonance (NMR) is an analytical technique that is capable of identifying soluble and organic forms of phosphate in milk. Thus, our objective was to investigate changes to the 31P NMR spectra of skim milk during microfiltration (MF) and diafiltration (DF) by tracking movements in different species of phosphate. In particular, we examined the peak at 1.11 ppm corresponding to inorganic phosphate in the serum, as well as the low-intensity broad signal between 1.5 and 3.0 ppm attributed to casein-associated phosphate in the retentate. The MF concentration and DF using water caused a shift in the relevant 31P NMR peak that could be minimized if orthophosphate was added to the DF water. However, this did not resolve the simultaneous change in retentate pH and increased solubilization of micellar casein protein. The addition of calcium in combination with orthophosphate prevented micellar casein solubilization and simultaneously contributed to preservation of the CPN structure, except for overcorrection of retentate pH in the acidic direction. A more complex DF solution, involving a combination of phosphate, calcium, and citrate, succeeded in both CPN and micellar casein structure preservation while maintaining retentate pH in the region of the original milk pH. The combination of 31P NMR as an analytical technique and experimental probe during MF/DF processes provided useful insights into changes occurring to CPN while retaining the micellar state of casein.