• Coffee-Stability of Agglomerated Whole Milk Powder and other Dairy Creamer Emulsions

      Kelly, Philip; Oldfield, D.J.; Teehan, C.M. (Teagasc, 1999-02-01)
      The objectives of this project were: (a) to investigate the circumstances that cause milk powders and creamers to fail when added to coffee based beverages; (b) to evaluate the role of processing variables in relation to their thermostabilising effects on milk during drying of coffee whiteners; and (c) to determine the role of emulsion formation on the stability of imitation creamers.
    • Development and Evaluation of Caseins/Caseinates for use as Ingredients in Food Products

      Mehra, Raj; Walsh, Daniel; O'Kennedy, Brendan; Kelly, Philip (Teagasc, 1998-09-01)
      The 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.
    • Ingredient Dehydration of Fermented and Flavour-Sensitive Products.

      Kelly, Philip; Keogh, M.K.; Kelly, J.; Kennedy, B. (Teagasc, 2001-08-01)
      Traditionally, yoghurt is produced in a hydrated form and, thus, possesses a limited shelf-life even when refrigerated. Consumption within a short time of production is advisable, particularly if advantage is to be taken of the putative benefits associated with the ingestion of live yoghurt cultures. The production of an instant yoghurt powder would, thus, provide benefits of shelf-life extension and convenience of preparation and storage. However, the drying of such products is difficult due to low pH, which causes stickiness in drier chambers and makes powder recovery difficult. Furthermore, key flavour components formed by fermentation such as acetaldehyde and diacetyl which contribute to the unique flavour of natural yoghurt are sensitive to heat and easily lost during spray-drying. Hence, a major challenge of this project was to investigate the processing technologies and conditions necessary for the minimisation of flavour losses during the spray-drying of acidified/fermented milk bases, to monitor the effects on drier performance such as powder adhesion to drier walls, and to develop functional forms of the spray-dried ingredients. The main aims of the project were to: - improve yoghurt powder spray-drying efficiency through optimisation of concentrate solids, - investigate the effect of spray-drying conditions on flavour losses of sensitive products such as dehydrated yoghurt and fermented creams,- apply technological approaches for the reduction of flavour losses: a) ingredient formulation, b) modification of fermentation conditions, - investigate the production of agglomerated forms of spray-dried yoghurt powders, - study factors affecting the physical properties such as rheological characteristics and powder bulk density, and - adapt technology to ensure greater viability of culture cell numbers at the end of the drying process.
    • Ingredient Development using a Pilot-Scale Tall-Form Spray Drier

      Kelly, Philip; Kelly, J.; Harrington, D. (Teagasc, 1998-02-01)
      The main objectives of the project were to establish relationships between process variables and product physicochemical/functional characteristics in the course of processing and drying new dairy-based ingredients such as high-fat and protein-rich products in regular and agglomerated forms. By establishing processing protocols, R&D users of the ingredient drying facilities of Moorepark Technology Ltd may be able to predict the process variables necessary for desired end-product specifications to be achieved, and thus make experimentation more efficient and cost effective, as well as facilitate small scale production runs and sample preparation for market development purposes. Particular emphasis was placed on the development of high fat cream and fat-filled powders, flavour-delivery systems and protein-enriched ingredients. The major achievement of this project is that it is now possible to confidently select the appropriate processing conditions during the spray drying of ingredients in order to attain desired end-product specifications. Based on the use of the newly-installed Tall-form drier, the project succeeded in correlating the effects of process parameters of this technicallyadvanced pilot plant with the physicochemical properties of powders containing varying fat (20-80%) and protein contents. In general, the physicochemical characteristics of fat-filled and cream-filled powders with similar fat contents were similar except for higher solubility index values (range 0.1-0.6) in the case of the former particularly in the range 26-28% fat. Furthermore, the free fat content of powders may now be controlled much more precisely using an appropriate combination of total fat, atomiser nozzle selection and post-drying blending.
    • 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.
    • Nutritional Studies on Dried Functional Food Ingredients Containing omega-3 Polyunsaturated Fatty-Acids.

      Kelly, Philip; Keogh, M.K.; Kelly, J.; O'Kennedy, Brendan; Murray, C.A. (Teagasc, 2000-10-01)
      The nutritional benefits of fish oils are generally attributed to their content of long chain omega-3 polyunsaturated fatty acids (PUFAs). Diets rich in these fatty acids are known to reduce the risk of coronary thrombosis, and are recommended to those who are susceptible to atherosclerosis. In addition, some of these long chain PUFAs play an important role in early infant nutrition, in the development of vital human organs such as the neural tube. However, practical difficulties arise in achieving an adequate daily intake of fish oils to obtain these physiological benefits. Per capita fish consumption is low in many countries, especially of oily fish with high levels of omega-3 PUFAs. Fish oil, while available as a dietary supplement, is not universally appealing in that form. Attempts to incorporate fish oil into food formulations have had limited success mainly because of fishy flavours coming through in the consumer products. Fish oil is particularly susceptible to oxidation, which results in fishy, painty and metallic flavours. Hence the main aim of this study was the development of a dried ingredient in which the formulation and related processing conditions were optimised to protect the fish oil from oxidation. Protection of any sensitive oil may be achieved by means of microencapsulation, whereby oil is dispersed as very fine droplets in emulsions. During subsequent spray drying the droplets are effectively sealed inside a protective coating of protein surrounded by carbohydrate. The objective was, therefore, to evaluate microencapsulation as a means of extending the shelf-life of fish oil in powder form thus increasing its versatility as a nutritional ingredient in food formulations.
    • Optimisation of Ingredient Formulation in Processed Meat Products.

      O'Kennedy, Brendan; Neville, Denis P.; Kelly, Philip (Teagasc, 2000-10-01)
      Reformed and restructured meat are two major categories of processed meat products. Reformed meat products require intact meat pieces to bind together while restructured meat products are extensively minced prior to restructuring. Salts such as sodium chloride and phosphates together with mechanical treatment and heat, have been used to bind meat pieces together. In the process the proteins in muscle become soluble, bind large amounts of water and gel on heating. While heat-induced gelation of soluble meat protein provides binding in reformed meat products and reduces cook losses in restructured meat products, no binding occurs in raw meat systems. Non-meat proteins, especially soya protein, are routinely used in processed meat products, often in conjunction with salts, to increase water and fat binding during the cooking process. However, such proteins do not bind intact meat pieces in either the raw or cooked state. Transglutaminase (TGase) is a food-grade commercially available enzyme which can crosslink suitable proteins leading to the formation of a protein matrix (gel) and immobilisation of large quantities of water. This property could improve the water-binding properties of non-meat proteins in restructured meat products. The prospect of crosslinking native meat proteins and non-meat proteins or native meat proteins on adjacent meat pieces would make salt-free reformed meat products a realistic objective. Hence, the main objective of this project was to study protein-protein interactions in reformed and restructured meats, especially between meat proteins and added non-meat proteins in the absence of salts but in the presence of a protein crosslinking enzyme.
    • β-Lactoglobulin: A Whey Protein Fraction with Enhanced Functionality

      Mehra, Raj; Raggett, Elaine; O'Kennedy, Brendan; Kelly, Philip; Rawle, Donal (Teagasc, 2001-08-01)
      Infant formula manufacturers are progressively moving towards the development of the next generation of infant milk formula based on the inclusion of α-lactalbumin-enriched ingredients in order to further ‘humanise’ baby milk, as well as to reduce the allergenicity associated with the presence of β-lactoglobulin ( β-lg). Since α-lactalbumin represents one of the two major whey protein fractions in bovine milk, the viability of new fractionation processes currently under development will depend inter alia on the functional value that will attach to the remaining fraction, namely β-lg. Since this protein fraction influences whey protein functionality for the most part, it is to be expected that its availability in an enriched form should lead to further enhancement of its key functional properties, and stimulate further market opportunities. It is therefore imperative that attention is given to the processes and functionality of β-lg produced by different processing approaches. Hence, the overall objective of the project was: - To source and/or produce sufficient quantities of β-lg-enriched ingredients obtained through whey protein fractionation using different technologies, and to evaluate their functionality in model and food systems. - To investigate the influence of thermal treatments and ionic environment on the molecular structure of purified β-lg in order to understand their effect on protein functionality (gelation). - To improve the water-holding capacity of β-lg-enriched fraction so that it could compete more favourably with carbohydrate hydrocolloids in food applications. Downstream processing of β-lg was manipulated to influence the composition, and hence the functional properties of β-lg-enriched fractions. * β-Lg-enriched fractions had enhanced functional properties compared to WPC 75 and WPI. * β-Lg-enriched fraction has clear advantages over conventional whey protein products (WPC, WPI), in that it can be tailor-made to have specific functional properties desired in particular food products. * Water-binding properties of β-lg-enriched fraction could be improved by multi-stage heating.