• Assessment of Food Ingredient Functionality using Laser Microscopy

      Keogh, M.K.; Auty, Mark (Teagasc, 1998-09-01)
      The objectives of this project were, to establish a confocal microscopy facility at Moorepark, to develop suitable methodology for the examination of food products and ingredients, to apply confocal microscopy techniques to food research projects and to use the above technological expertise for commercial applications in the Irish Food Industry. The confocal laser scanning microscopy (CLSM) facility is now established and is fully integrated into the Teagasc research program at Moorepark. The new Confocal Microscopy Service has attracted significant commercial interest and client work is expanding. Results show that confocal laser scanning microscopy is a valuable technique for assessing the functionality of food ingredients in a wide range of food products, as well as being a powerful problem-solving tool. Work is ongoing to develop further specific ingredient localisation techniques, and to promote commercial awareness of the service. Confocal laser scanning microscopy offers a unique contribution to product research and development in the Irish food industry.
    • Dairy Ingredients for Chocolate and Confectionery Products.

      Keogh, M.K.; Twomey, Myra; O'Kennedy, Brendan; Auty, Mark; Kennedy, R.; O'Keeffe, James; Kelleher, Colin T (Teagasc, 2001-05-01)
      High free-fat, spray-dried powders were successfully produced at a lower fat content (40% rather than 56%) using ultrafiltration. Chocolates made from these powders had improved flow properties and superior quality. The stability, viscosity and firmness of toffees were improved by optimising the casein, whey protein and lactose levels of skim milk powders used in their manufacture.
    • Dairy Ingredients for the Baking Industry.

      Keogh, M.K.; Neville, Denis P.; STANTON, CATHERINE; Auty, Mark; Kennedy, R.; Arendt, Elke (Teagasc, 2001-08-01)
      Shortenings (baking fats), microencapsulated using dairy ingredients and milk protein hydrolysates, were produced for testing in a variety of baked products. The powders were evaluated for their functionality as powdered baking fats, as potential replacers of synthetic emulsifiers, as ingredients capable of improving baking performance or as potential health-enhancing ingredients. These studies provide the technology for the dairy industry to enter the specialised food ingredients sector with a siftable, non-greasy, free-flowing powdered fat for the baking industry.
    • Dairy Ingredients in Chocolate

      Keogh, M.K.; O'Kennedy, Brendan; Twomey, Myra; O'Brien, Nora M.; Kennedy, B.; Gorry, C. (Teagasc, 1998-09-01)
      The main objective was to assess and control the contribution of various ingredient components to chocolate behaviour and to optimise ingredients for specific chocolate applications. A key aim, therefore, was to understand the role of composition and particle structure and to produce spray dried powders with a functionality in chocolate as close as possible to roller dried powders. By demonstrating how the powder properties affect chocolate, it should be possible to control the functional properties of the powders to meet any powder or chocolate specification. Novel powder compositions indicated by this work should also be useful to chocolate makers. The ability to make chocolate under test conditions and to assess the role of milk powders or other ingredients has been put in place for the first time in Ireland. Previous knowledge of milk seasonality and of powder technology has provided a basis for understanding variations in milk powder functionality in chocolate. Spray dried powders with mean free fat values of 50 to 94%, particle sizes of 30 to 65 mm and vacuole volumes of 0.0 to 3.9 ml/100g were produced from milks of varying composition but under the same processing conditions. Advances were made in analysing powder structure through microscopy, particle size and occluded air measurement. Valuable new information has been generated on the changes in free fat, solid fat content, particle size and occluded air in powders. Explanations were provided for the first time for the complex effects of these properties on chocolate viscosity and yield value. This information will also make a positive contribution to other projects in the milk powder area. Good contacts have been established with multinational manufacturers and with producers of milk powder for chocolate.
    • Development of a Range of Encapsulated Milk Fat Products

      Keogh, M.K.; O'Kennedy, Brendan; Neville, Denis P.; Kennedy, B.; Gorry, C. (Teagasc, 1998-09-01)
      The aims of this research were to determine the effects of milk composition (fat, whey protein, lactose and salts) and process (homogenisation) factors on the formation of emulsions and microencapsulated powder particles and to relate these to the properties of the powder, especially susceptibility to fat oxidation. The effect of composition, using sodium caseinate and lactose on the production of high fat powders was also studied. Finally, new developments in microencapsulated milk powders were undertaken in collaboration with industry using sodium caseinate and lactose. Overall, the microencapsulation process should provide a technique to extend the shelf-life of sensitive fats and flavours and to produce high fat powders for a range of end-uses. The major components of the emulsions used to make the microencapsulated powders influenced fat globule diameter and stability, but the minor salt components also affected globule size and stability. Free flowing high fat (70%) powders with sodium caseinate and lactose as encapsulants were manufactured using a tall-form Niro spray dryer with fluidised beds. A flavoured ingredient using a by-product flavoured fat as the flavour agent was made using the same encapsulants. Microencapsulated powders were incorporated into baked goods as multi-functional ingredients. They increased loaf volumes and improved handling and processability of the dough, thereby extending the product range for fat and other dairy ingredients used for baking. Microencapsulated 80% fat blends were manufactured for biscuit formulations to overcome the handling problems associated with bulk fats. This sub-project also gave rise to a leading role in a EU FAIR project on the microencapsulation of fish oil for use in functional foods using milk components as the sole encapsulants.
    • 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.
    • 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.