Browsing by Author "MacGregor, Elizabeth"

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    The development and evaluation of measurements on spaghetti with diverse quality characteristics
    (Stellenbosch : University of Stellenbosch, 2005-04) MacGregor, Elizabeth; Vosloo, M. C.; Vorster, S. H.; University of Stellenbosch. Faculty of Agrisciences. Dept. of Consumer Science.
    ENGLISH ABSTRACT: Pasta manufacturing is a process whereby wheat flour is converted into a shelf-stable food that is more desirable than native wheat flour. It can be fortified and may serve as a valuable source of nutrition in developing countries. Quality measures are of importance in the production process to ensure a consistent and acceptable finished product. Literature provides information on many aspects of wheat types, milling techniques and processing of pasta. Protein content and quality of cultivated wheat varieties is of major importance to produce quality pasta products. Wheat types of lower protein content are more readily available than traditionally used durum wheat. As in all food products, the cost of final products is of major importance. Bread wheat is generally less expensive than durum wheat. However, product quality (and thus acceptability) may be lower. Direct measurements of product quality are currently limited to protein content, moisture content, colour analyses and certain other characteristics measurable in a laboratory, for example mechanical strength and firmness. Direct measurements of defects that may affect final product quality, such as cracks and fissures on the strands of spaghetti, different types of spots and lines on the strands, broken units, units sticking together and odd shapes are not well documented. During the first part of this study, spaghetti quality evaluation techniques were reviewed, improved or developed and thereafter standardised. This developmental research was conducted to establish valid and reliable measures (with a high degree of repeatability) for the evaluation of dry and cooked pasta quality characteristics. A wide variety of available products on the South African market were evaluated for different quality characteristics. From this evaluation standards were drawn up, tested for validity and reliability by means of repeatability. Minimum sample sizes for the evaluation of different quality characteristics were calculated and presented in the study, together with reference photographs that can be used to evaluate spaghetti. This study found that colour evaluation by means of commercially available apparatus needs revision. This study suggests the use of multiple layers when evaluating translucent food products for colour. The occurrence of fissures and flour spots are of importance for the quality of the final product. This study provides a set of valid and reliable measurements for measuring the quality of dry and cooked spaghetti. Simple techniques can therefore be used to detect the presence or absence of these defects. Thereafter an empirical study was conducted to describe the differences between spaghetti prepared from durum and non-durum wheat, dried at different temperatures and at different relative humidity. Spaghetti samples of diverse perceived quality, from different manufacturers, were purchased and evaluated. Standard methods and the newly developed testing methods were used to test whether these methods effectively distinguish between spaghetti of diverse quality, reflecting on the validity of the methods. Correlations were calculated between dependent and independent variables in an attempt to find possible explanations for certain defects or quality differences, and to test certain theories in the literature. Certain relationships between quality characteristics were found, while others were questioned. The most important proven relationships were between protein content and its effects on reducing quality defects such as fissures, breakages and cooking losses. The relationship between ash content and spaghetti colour could not be confirmed in this study. This study confirmed that protein remains one of the most important variables to ensure consistent quality spaghetti.