Plant Bioactives Group, Post-Harvest and Agro-Processing Technologies, Agricultural Research Council (ARC), Infruitec-Nietvoorbij, Private Bag X5026, Stellenbosch 7599, South Africa; Department of Food Science, Stellenbosch University, Private Bag X1 Matieland, Stellenbosch 7602, South Africa.
Department of Food Science, Stellenbosch University, Private Bag X1 Matieland, Stellenbosch 7602, South Africa.
Food Res Int. 2019 Nov;125:108519. doi: 10.1016/j.foodres.2019.108519. Epub 2019 Jun 24.
Variation in the bitter taste of Cyclopia genistoides (honeybush) herbal tea and reported modulation between its major xanthones, mangiferin and isomangiferin, prompted further investigation into the potential modulatory effects of honeybush phenolics. Combinations of crude benzophenone (BF)-, xanthone (XF)-, and flavanone (FF)-rich fractions and their major individual phenolic compounds were analysed by descriptive sensory analysis. The fractions were prepared from a bitter, hot water extract of green C. genistoides. Fraction BF, which is below the bitter threshold (intensity 10 on 100-point scale), enhanced the bitter intensity of XF and FF slightly (p < 0.05), although none of the major individual benzophenones retained this bitter enhancing effect. On the contrary, 3-β-d-glucopyranosyl-4-β-d-glucopyranosyloxyiriflophenone, the major benzophenone in BF, significantly (p < 0.05) decreased the bitter taste of XF, at a low concentration, whereas FF suppressed the bitter intensity of XF and mangiferin, the major xanthone present in XF. Hesperidin, however, had no effect on the bitter intensity of XF. In contrast, (2S)-5-[α-L-rhamnopyranosyl-(1→2)-β-d-glucopyranosyloxy]-naringenin, the major compound of FF, significantly (p < 0.05) enhanced the bitter taste of XF when added at concentrations comparable to that of 'fermented' honeybush tea infusions. The concentration-dependence of these bitter taste interactions may be responsible for the variable bitter intensity of C. genistoides herbal tea.
由于 Cyclopia genistoides（霍桑茶）草药茶的苦味变化及其主要黄烷酮芒果苷和异芒果苷之间报道的调节作用，促使进一步研究霍桑酚类物质的潜在调节作用。通过描述性感官分析分析了粗苯并二酮（BF）、黄烷酮（XF）和黄烷酮（FF）丰富的馏分及其主要的酚类化合物组合。这些馏分是从绿色 C.genistoides 的苦味热水提取物中制备的。馏分 BF 的苦味强度低于苦味阈值（100 点标度上的强度为 10），略微增强了 XF 和 FF 的苦味强度（p<0.05），尽管没有一种主要的苯并二酮保留这种增强苦味的作用。相反，3-β-d-吡喃葡萄糖基-4-β-d-吡喃葡萄糖基氧基伊夫lophenone，BF 中的主要苯并二酮，在低浓度下显著（p<0.05）降低了 XF 的苦味，而 FF 抑制了 XF 和 XF 中主要黄烷酮芒果苷的苦味强度。然而，橙皮苷对 XF 的苦味强度没有影响。相比之下，（2S）-5-[α-L-鼠李吡喃糖基-（1→2）-β-d-吡喃葡萄糖基氧基]-柚皮苷，FF 的主要化合物，当添加浓度与“发酵”霍桑茶浸液相当时，显著（p<0.05）增强了 XF 的苦味。这些苦味相互作用的浓度依赖性可能是 C.genistoides 草药茶苦味强度变化的原因。
