Journal of Tea Science Research, 2024, Vol.14, No.3, 148-159 http://hortherbpublisher.com/index.php/jtsr 153 Stander et al. (2020) studied the diversity of thin-layer chromatography (TLC) banding patterns in various rooibos tea samples (Figure 2). They found that bands 1-6 were commonly observed in both commercial and wild rooibos tea samples, while bands A and B were only found in selected plants. The study revealed significant differences in the presence of major phenolic compounds among different rooibos tea plants. These findings emphasize the importance of genetic diversity in rooibos tea plants and its significant impact on their chemical composition. The unique phenolic compounds found in specific plants may offer new avenues for enhancing the antioxidant properties and health benefits of rooibos tea. 5.2 Environmental influences on chemical composition Environmental factors, including soil quality, temperature, and seasonal variations, play a crucial role in determining the chemical composition of rooibos tea. Soil quality, for instance, has been found to influence the phenolic content and overall yield of rooibos plants. Poor soil conditions, such as those with low organic matter and essential nutrients, can lead to decreased yields and lower quality tea (Smith et al., 2017). Temperature also significantly affects the growth and phenolic content of rooibos plants. Elevated temperatures can lead to stress responses in plants, altering their phenolic profiles and potentially reducing tea quality (MacAlister et al., 2020). Additionally, the production season impacts the phenolic content of the tea, with variations observed across different seasons (Stanimirova et al., 2013). 5.3 Interaction between genetics and environment The interaction between genetic factors and environmental conditions further complicates the quality of rooibos tea. For example, specific genetic variants of rooibos may respond differently to environmental stresses, resulting in varied phenolic profiles and tea quality. Research indicates that fermentation and drying conditions significantly impact the quality of rooibos tea, with both genetic and environmental factors contributing to these effects (Yang et al., 2020). The quality of rooibos tea is determined by a dynamic interplay of genetic diversity and environmental influences. Understanding these factors can help in optimizing cultivation practices to enhance the quality and health benefits of rooibos tea. 6 Case Studies 6.1 Antioxidant properties of fermented rooibos tea Fermented rooibos tea is known for its distinctive reddish-brown color and has been widely studied for its antioxidant properties (Figure 3), while unfermented rooibos tea retains a green color (Dludla et al., 2017). The fermentation process affects the polyphenol content, which in turn influences the tea's antioxidant capacity. Studies have shown that fermented rooibos tea contains a variety of polyphenols, including aspalathin and nothofagin, which contribute to its antioxidant activity (McKay and Blumberg, 2007; Moosa et al., 2018). The total antioxidant activity (TAA) of fermented rooibos is lower compared to unfermented rooibos, yet it still exhibits significant radical scavenging properties (Bramati et al., 2003; Moosa et al., 2018). Additionally, fermented rooibos has been found to inhibit osteoclast formation and activity, which is beneficial for bone health, potentially due to its antioxidant properties (Moosa et al., 2018). The consumption of fermented rooibos has also been linked to improved lipid profiles and reduced oxidative stress markers in adults at risk for cardiovascular disease, further highlighting its health benefits (Marnewick et al., 2011). 6.2 Health benefits of unfermented rooibos tea Unfermented rooibos tea, often referred to as "green" rooibos, retains a higher content of flavonoids compared to its fermented counterpart. This higher flavonoid content translates to a greater total antioxidant activity, which is approximately twice that of fermented rooibos (Bramati et al., 2003). Unfermented rooibos has been shown to significantly increase plasma total antioxidant capacity in healthy humans, indicating its potential to enhance the body's defense against oxidative stress (Villaño et al., 2010). Moreover, unfermented rooibos has demonstrated neuroprotective and anxiolytic properties, making it a promising candidate for functional brain food and
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