Development of chemical-based reference standards for rooibos and honeybush aroma lexicons.

The honeybush sensory wheel was revised, using a large sample set (n = 585) comprising of the major commercial Cyclopia species, i.e. C. intermedia, C. subternata and C. genistoides. Only positive and negative aroma attributes were included in the wheel. Chemicals were identified to serve as reference standards for the honeybush (Cyclopia spp.) lexicon. Similarly, chemical-based reference standards were identified for the rooibos (Aspalathus linearis) lexicon. From a comprehensive literature search and gas chromatography-mass spectrometry analyses, chemicals were screened by an expert panel for their suitability in terms of typicality of the target aroma. Each chemical was evaluated in a 'base tea' and compared to a specific 'reference tea' exhibiting a high intensity of the target aroma. A total of 30 and 44 chemicals for rooibos and honeybush, respectively, were selected for validation by a trained panel. Descriptive sensory analysis was conducted to assign typicality and intensity scores for each chemical representing a target aroma attribute. Several chemicals were identified as suitable reference standards for the following aroma notes: isophorone ('rooibos-woody'), maltyl isobutyrate ('caramel'), cis-3-hexenol ('green grass'), 4-oxoisophorone ('seaweed') and 2,4,6-trichloroanisole ('musty/mouldy') for rooibos; and 2-acetyl-5-methylfuran ('woody'), levulinic acid ('fynbos-sweet'), maltyl isobutyrate ('caramel'), and 2-acetylpyrrole ('nutty') for honeybush.

Sensory and functional meat quality characteristics of pork derived from three halothane genotypes.

The effect of the halothane gene in pigs on the meat and sensory qualities thereof were determined. Meat derived from 60 Landrace×Large White pigs of three halothane genotypes was used. The sensory qualities, cooking loss, colour, shear value and proximate analysis of the cooked pork loin roasts were determined. The three genotypes did not differ significantly (P>0.05) with regard to the colour of the cooked meat, percentage cooking loss and percentage moisture. There were significant differences (P<0.05) between the genotypes in the percentage protein, ash and fat. Meat from the three genotypes also differed significantly (P<0.05) in juiciness, an analytical sensory panel scored the juiciness of meat from the NN-genotype the highest with a value of 71.3 when using a structured line scale. Meat from the nn-genotype had the lowest score for juiciness (62.8). Meat from the three genotypes did not differ significantly (P>0.05) with regard to tenderness, pork flavour and no mealiness. Correlation values showed a positive correlation (r=0.46, P<0.05) between juiciness and tenderness. These results indicate that the inclusion of the halothane gene in pig production programmes results in meat with an inferior quality and it can be recommended to exclude the halothane positive genotype from any pig production system where fresh pork quality is considered a primary goal.