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    Consumer input and product concept testing in developing dried fruit snack prototype for Malaysian market : thesis presented in partial fulfilment of the requirement for the degree of Master of Technology in Product Development at Massey University
    (Massey University, 1996) Ibrahim, Aida Hamimi
    The input of the consumer when developing a dried snack fruit for the Malaysian market using the product development process was studied. A consumer panel made up of Malaysian students was used in each step of the product development process in this study. Preliminary consumer research was carried out using the focus group and the survey method. The results indicated that the two ethnic groups, Malay and Chinese, within the Malaysian student community could be treated as a homogenous group as they had similar attitude and behaviour characteristics towards the dried snack fruit product. Both student groups had been studying in New Zealand for less than two years. In the idea generation stage, the consumer panel generated 41 product ideas for the dried snack fruit using the nominal group technique. The 41 product ideas were reduced to three using a series of scoring techniques for screening. At this stage, consumer input was used to determine the market acceptability of the three possible products. These three product ideas with a benchmark were tested in concept product testing using the target consumer panel to evaluate consumer acceptability. Two different forms, concept description and concept prototypes, of concept testing using two different techniques, the focus group technique and the survey method, were tested in order to determine any significant effects they had on consumer acceptability. It was found that the concept prototypes had a significant effect on the consumers' preferences for product concept appearance, attractiveness and, buying intention. The two different techniques however, did not have a significant effect on the consumer acceptability of the product concepts. Of the two techniques, the focus group required less time for data collection compared to the survey technique, but the focus group was more expensive to run. By using the ECHIP programme and the line scale with floating ideals, which was the input of the consumers in the sensory evaluation stage, an optimum product formulation for the dried fruit snack was obtained. The prototype consisted of six types of fruit namely, apple (0.25), kiwifruit (0.25), banana (0.175), pineapple (0.13) strawberry (0.125) and jackfruit (0.07) with their natural flavours. The prototype was tested on the target consumer using in- house tests in order to determine the acceptability potential of the prototype. The results showed that the idea of developing the dried fruit snack with their natural flavours was acceptable among the Malaysian students. Freeze drying was found to be the most preferred drying process for the dried snack fruit product. The acceptable package size of the product by consumer panel was 40gm. Consumer input played a major role in the product development process in this project and it gave direction in the development of the dried snack fruit product for the Malaysian market. Consumer input was found to be vital during the preliminary consumer research, idea generation, concept testing, product formulation stages, and the final product testing phase in this study.
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    Shelf life prediction of dried fruit and vegetables : a quantitative approach : a thesis presented in partial fulfilment of the requirements for the degree of Doctor of Philosophy in Food Technology at Massey University
    (Massey University, 1989) Samaniego-Esguerra, Christine Marie
    The quantitative approach to shelf life prediction of foods is a relatively new field of food technology and the paucity of published studies in this area indicates a need for further research. The present study was undertaken to develop and evaluate a methodology for the shelf life prediction of packaged dried foods using a quantitative approach. The development of a technique for the shelf life prediction of packaged dried foods, specifically onion flakes, sliced green beans, and apricot halves, involved the mathematical modelling of product and package characteristics as functions of environmental conditions, i.e. temperature and humidity. The WVTR and permeability constants of LDPE (60 µm), PET (12 µm) and a laminate of both films (30 µm LDPE and 12 µm PET) were determined at different temperatures and humidities. A general model was developed which satisfactorily predicted permeances of the three films as a function of external relative humidity and temperature. The moisture sorption isotherms of the three products were determined at 20, 30, and 40°C. The GAB model adequately described the isotherms using a direct nonlinear regression analysis. The kinetics of the deteriorative reactions limiting the shelf life of the three dried products and their acceptable limits were determined. Storage trials were conducted on the three products under different relative humidity (32% to 59% RH for dried onion flakes and green beans; 59% to 81% RH for dried apricot) and temperature (20°C to 40°C) conditions. Nonenzymic browning in onion flakes and chlorophyll a loss in green beans were better described by a zeto-order reaction model. Thiolsulphinate loss in onion flakes, nonenzymic browning in apricot, and SO2 loss in both green beans and apricots were better described by a first-order reaction model. For onion flakes and green beans, the rates of reactions were found to increase with an increase in the water activity of the products. Empirical equations were derived describing the relationship between the rates of reactions and water activity. The Arrhenius equation satisfactorily described the relationship between rate constants and temperature. Nonensymic browning and sulphur dioxide loss in dried apricots exhibited a trend wherein the rate increased with water activity until a maximum was reached and then decreased with a further increase in water activity. The reactions followed the Arrhenius equation at all three water activity levels. Mathematical models of quality deterioration in the dried foods were developed based on the theoretical and empirical equations obtained on the kinetics of the deteriorative reactions as functions of storage time, water activity and temperature. There was close agreement between the actual and predicted shelf lives of the unpackaged dried foods stored under variable temperature and relative humidity conditions. In order to predict the shelf life of the dried products packaged in polymeric films, a computer iterative technique was developed which combined the models describing the permeability characteristics of the packaging films, the sorption properties of the product, the kinetics of deterioration in the products and the mass transport equation. By solving these equations numerically with the aid of a computer, moisture gain, quality loss and shelf life of the products were satisfactorily predicted under various storage conditions.