Plant Bioactives Group, Post-Harvest & Agro-Processing Technologies, Agricultural Research Council (ARC), Infruitec-Nietvoorbij, Stellenbosch, South Africa.
Department of Food Science, Stellenbosch University, Stellenbosch, South Africa.
J Sci Food Agric. 2019 May;99(7):3653-3661. doi: 10.1002/jsfa.9587. Epub 2019 Mar 6.
Rooibos represents 10% of the global herbal tea market. Shrinking production areas as a result of climate change necessitate the maximum conversion of plant biomass to product. The present study aimed to determine the potential of rooibos tea processing waste (i.e. fine dust and coarse stems) as potential flavour and herbal tea ingredients, respectively.
Hot water extraction of soluble solids (SS) from rooibos dust was optimised and extracts from different production batches (n = 20) were prepared. Their sensory profiles were similar, although less intense than that of infusions of commercial rooibos (n = 20) when diluted to the same SS content. The turbidity and flavonoid content of the diluted extracts was mostly lower (P < 0.05) than that of commercial rooibos. An atypical and negative aroma attribute, 'planky/pencil shavings', was predominant in the stem infusions (n = 20), which contained less SS (P < 0.05) than commercial rooibos. Blends of stem infusion and extract could not effectively mask this negative aroma note (P > 0.05).
Rooibos dust could be used to produce a rooibos flavour extract, whereas the prominent atypical, negative 'planky/pencil shavings' aroma note of the stems would limit their inclusion in commercial rooibos blends. © 2019 Society of Chemical Industry.
路易波士茶占全球草本茶市场的 10%。由于气候变化导致生产区域缩小，有必要将植物生物质最大限度地转化为产品。本研究旨在分别确定路易波士茶加工废料（即细粉和粗茎）作为潜在风味和草本茶成分的潜力。
对路易波士茶细粉中的可溶性固形物（SS）进行热水提取优化，并用来自不同生产批次（n=20）的提取物进行制备。它们的感官特征相似，尽管与商业路易波士茶（n=20）的浸出物相比，稀释到相同的 SS 含量时，其强度稍低。稀释提取物的浊度和类黄酮含量大多低于商业路易波士茶（P<0.05）。一种非典型的负香属性，“刨花/铅笔屑”，在茎浸出物中占主导地位（n=20），其 SS 含量低于商业路易波士茶（P<0.05）。茎浸出物和提取物的混合物不能有效地掩盖这种负香气味（P>0.05）。
路易波士茶细粉可用于生产路易波士风味提取物，而茎部突出的非典型、负向的“刨花/铅笔屑”香气会限制其在商业路易波士茶混合物中的加入。© 2019 英国化学工业学会。
