Browsing by Author "Uaphithak, Hathairat"

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    Consumer research and product optimization for glue stick development in Thailand : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Product Development at Massey University
    (Massey University, 1994) Uaphithak, Hathairat
    This study, on the development of a new glue stick product based on tapioca starch for Thai consumers, had a major emphasis on the use of consumer input in the product optimization. At the beginning of the development process consumers identified the problems of existing products and generated the important attributes of glue stick products. Then product prototypes were made using mixture experimental designs and quantitative relationships between the ingredients and the product attributes were determined. For evaluating the sensory attributes of prototypes, a trained panel was employed during the development of the first prototypes and then a consumer panel in the second prototype development. Consumers not only evaluated the product attributes of the prototype products using line scales but also indicated their ideal product attribute levels. Physical attributes of the products were also measured. Multiple regression was used to generate the empirical equations showing the relationships between the ingredients and the product attributes. These linear relationships were then used to develop the constraints for a linear programming model. The consumer ideal product profile as well as the sensory profiles of the commercial products were employed to create upper and lower acceptable limits of the attributes' constraints. The raw materials and the physical properties were also included in the linear programming model. Acceptability maximization and cost minimization were used to generate the optimum formulations. The prototype products from these formulations were tested by a small consumer panel to select the one with highest acceptability. A pilot scale plant was designed and built and then a small quantity of the final formulation was produced. The final product, from the successful pilot scale production, was tested in a home-use test by 108 students and 64 office workers in Bangkok. The consumers evaluated the performance of the developed product in comparison with their 'usual brand'. The results from the consumer testing showed that the developed glue stick was generally accepted by the target consumers. However, some improvements of the product in terms of colour, aroma and packaging are still necessary. The product could be made commercially in Thailand in a simple plant using a closed stainless steel vessel with steam jacket, condenser and central anchor type mixer. Suitable packaging equipment is needed in order to maintain the high temperature of the mix while discharging the glue mixture into moulds. The product should be able to compete with the glue sticks already in the Thai market since it has the distinctive feature of adjustability and could be sold at a lower price.
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    Linear programming and consumers' ideal sensory attributes in product optimization : a thesis presented in partial fulfilment of the requirements for the degree of Master of Technology in Product Development at Massey University
    (Massey University, 1990) Uaphithak, Hathairat
    Sensory attribute/ingredient relationships and consumers' ideal product profile were used to develop constraints for linear' programming in hand cream optimization using rice bran oil to replace mineral oil. At the beginning of the process, consumer testing was conducted in order to elicit the important attributes of the product as perceived by the consumers. Simultaneously, the strengths and weaknesses of hand creams on the market were identified, and an ideal product profile developed for hand creams. A fractional factorial design, 26 2, was used to identify the main effects of the ingredients on the product attributes. A quantitative sensory profile technique and a trained sensory panel were employed in the product sensory evaluation of the samples. The mean scores of each sensory attribute were regressed against the levels of the ingredients in the formulations. Only the main effects of the ingredients were identified according to the design of the experiment. Most sensory attributes, consistency, spreadability, oiliness, shine and stickiness, had significant linear relationships with the ingredients. Moistness, softness and absorbability did not. The linear relationships were then used to develop sensory constraints for the linear programming model. Upper and lower limits of these constraints were set from the consumers' ideal product profile, by adding and subtracting 1 from the ideal attribute levels. Other constraints were on ingredient levels based on formulation needs. LP88 computer program was used to solve this hand cream problem, the objective being minimum cost. A hand cream was made using the optimum formulation from the linear programming and tested with the trained sensory panel. Ideal ratio scores (i.e. ratio of the sample mean score to the ideal score) of this hand cream's attributes were not more than 0.3 away from the ideal. The product was then tested with a consumer panel of 20 hand cream users. In consumer testing, the optimum product was tested along with the leading commercial products in order to compare consumer acceptability on these products and to test if the optimum product could compete with the products already in the market. The results showed the consumers preferred the optimum product to the commercial products and the optimum product was closer to the ideal. From the linear programming model used in this study, the attribute levels of the hand cream can be modified by adjusting the constraints and studies can be made of the effect of changes in ingredients on product attributes.