The phenolic quality of commercial South African fermented rooibos iced teas in terms of aspalathin, iso-orientin, and orientin contents in comparison to a "cup of tea" was shown to be inferior. The role of the different manufacturing stages of powdered extract used in iced tea formulation and, more specifically, the impact of pasteurization and sterilization on the color and phenolic content of the beverage, were assessed as potential causes of its inferior phenolic quality. Aspalathin and its corresponding flavones, iso-orientin and orientin, were found to be present at all stages of the powdered extract production process. Spray-drying did not significantly (P ≥ 0.05) alter the aspalathin, iso-orientin, or orientin content of concentrates. Simulated normal-temperature sterilization (NTS at 121 °C/15 min) and high-temperature sterilization (HTS at 135 °C/4 min), but not necessarily pasteurization (93 °C/30 min), significantly (P < 0.05) reduced the aspalathin, iso-orientin, and orientin contents of different iced tea formulations. Heat-induced losses of iso-orientin and orientin were lower than those for aspalathin. Conversion of aspalathin to the flavones is implicated. The addition of ascorbic acid and/or citric acid to the base iced tea formulation containing only rooibos extract and sugar proved to be beneficial, especially for the retention of aspalathin. Browning, that is, absorbance at 420 nm, was significantly (P < 0.05) increased in the base formulation. In the case of the formulations also containing ascorbic acid and/or citric acid, absorbance remained unchanged or decreased when subjected to NTS and HTS treatments. This was attributed to removal of brown polymers from solution as the pH values of these formulations were lower than that of the base formulation.

Near infrared reflectance spectroscopy (NIRS) was evaluated as a tool to predict the chemical composition of freeze-dried mutton. Samples used for the ash, dry matter (DM),

Grain samples were produced at 10 different locations in the Western Cape region of South Africa, on 2.1 m x 6 m experimental plots, over a period of three years. Twenty different cereal grain cultivars were used in the study. A randomised square experimental design with four replicates per sample was used. An area of 1.35 m x 5 m from each plot was harvested during 1994, 1995 and 1996 and the yield was determined. Thousand seed mass (TSM) and hectolitre mass (HLM) were also determined. Samples were analysed for dry matter (DM), ash, crude protein (CP), ether extract (EE), neutral detergent fibre (NDF), acid detergent fibre (ADF) and in vitro organic matter digestibility (IVOMD). Digestible energy values (DE) for pigs were determined with a mobile nylon bag technique, while non-structural carbohydrate values (NSC) were calculated. In the first analysis, cultivars were compared by a one-way analysis of variance, followed by pooling of grain type data. Naked oats had the highest DE value, and the respective values (DM basis) for naked oats, wheat, triticale, 2-row brewer's barley, 6-row feed barley and oats were 18.0, 16.0, 15.8, 14.9, 14.4, and 12.6 MJ/kg DM. The high EE value of naked oats (97 g/kg) might be partly responsible for the high DE value. The 6-row and 2-row naked barley cultivars had the highest IVOMD (946 g/kg and 944 g/kg), followed by wheat (910 g/kg), triticale (905 g/kg), naked oats (899 g/kg), 2-row brewer's barley (882 g/kg), 6-row feed barley (844 g/kg) and oats (671 g/kg). Considerable variation was found between samples within a cultivar for DE and IVOMD. Two-row naked barley had the highest mean CP value (159 g/kg) followed by naked oats (159 g/kg), 6-row naked barley (154 g/kg), wheat (148 g/kg), triticale (146 g/kg), oats (143 g/kg), 2-row brewer's barley (136 g/kg) and 6-row feed barley (135 g/kg) on DM basis. Triticale had the highest yield, with naked oats and barley cultivars having the lowest yield.

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Citric and ascorbic acids contribute to the stability of rooibos flavonoids during storage. Differences in stability between formulations are not due to pH differences but may be related to the matrix.