Browsing by Author "Moelich, Erika Ilette"

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    Development and validation of prediction models and rapid sensory methodologies to understand intrinsic bitterness of Cyclopia genistoides
    (Stellenbosch : Stellenbosch University, 2018-03) Moelich, Erika Ilette; Joubert, E.; Muller, M.; Næs, T.; Stellenbosch University. Faculty of AgriScience. Dept. of Food Science.
    ENGLISH ABSTRACT: Cyclopia species, endemic to South Africa, is used for the production of honeybush tea. This herbal tea has grown from a product consumed only locally to one currently marketed worldwide. Cyclopia species is high in polyphenols, well-known for its health related properties, but these compounds could contribute to bitterness, which may elicit negative consumer response. One of the species, C. genistoides, is high in polyphenols but also associated with bitterness, contrary to the characteristic sweet taste and honey-like flavour associated with honeybush. The polyphenolic content of four Cyclopia species were quantified with high-performance liquid chromatography diode-array detection while descriptive sensory analysis (DSA) was used to determine the taste intensities of these samples. The link between phenolic content and bitterness was investigated. Based in the phenolic content of C. genistoides and C. longifolia, partial least squares (PLS) regression analysis identified four compounds, mangiferin, isomangiferin, iriflophenone-3-C-glucoside-4-O-glucoside and iriflophenone-3-C-glucoside, as candidate predictors of bitterness. This model will find application as screening tool in cultivar development research programs. Production of honeybush lags behind demand, forcing the industry to use blends of Cyclopia species, including C. genistoides, to supply in the increased demand. The distinct differences in the sensory profiles associated with different Cyclopia species require that special care is given to blending to ensure a consistent, high quality product. DSA was used to evaluate the effect of blending of C. genistoides with other Cyclopia species on bitterness. Blending of C. genistoides with C. subternata, C. intermedia or C. maculata in a ratio of 2:3 were effective in reducing bitterness to below perceptible levels. The sensory profile of C. genistoides- C. subternata blends were further quantified using DSA and was described as “fynbos floral”, “apricot”, “woody”, “fruity sweet” and “fynbos sweet” aroma and a sweet taste. Based on these results, inclusion of C. genistoides at 40% when blending different Cyclopia species, is recommended. Blending at this standardised ratio will result in a well-rounded product with bitterness below perceptible levels. The herbal tea industry expressed the need for time- and cost-effective methods for sensory screening of infusions to improve quality and product consistency. The validity of three rapid profiling methods {sorting, projective mapping and polarised sensory positioning (PSP)} for the sensory characterisation of honeybush infusions were investigated using a trained panel. The efficacy of partial (aroma or palate attributes) or global (all attributes) evaluation was compared within each rapid method. Product configurations similar to that of DSA demonstrated the validity of all three methods for broad sensory profiling of Cyclopia species. Sorting on palate attributes resulted in additional differentiation between samples with only subtle differences. Sorting demonstrated to be the most effective method for the broad sensory profiling of honeybush infusions and could find application in the honeybush industry as screening tool. PSP on the other hand could find application in quality control programs where poles that represent specific quality attributes, should be included. Implementation of valid, scientific methods, such as sorting and PSP, will aid the honeybush industry in their effort to supply a product with consistent quality and high consumer appeal.
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    Sensory and objective meat quality characteristics of pork from three halothane genotypes
    (Stellenbosch : Stellenbosch University, 1999) Moelich, Erika Ilette; Stellenbosch University. Faculty of . Dept. of .