Best@BUCHI #41: Near Infrared Spectroscopy in Natural Plant Products

Best@BUCHI: NIR Spectroscopy on Natural Plant ProductsUse of Near Infrared Spectroscopy in quality control of green Rooibos and Honeybush

The growing interest in natural plant products by the nutraceutical and cosmetic industries during the past number of years has resulted in a large number of polyphenolenriched extracts on the market. Rooibos (Aspalathus linearis) and honeybush (Cyclopia spp.) are two indigenous South African herbal plants containing high quantities of the polyphenolic compounds, aspalathin and mangiferin, respectively, contributing to their antioxidant activity.

Review the full Best@BUCHI study for Near Infrared Spectroscopy.

Utilizing Near Infrared Spectroscopy (NIRS), a Buchi NIRLab N-200 Fourier transform near infrared (FT-NIR) spectrophotometer with NIRLabWare (version 3.0) near infrared (NIR) measurement software was used to develop calibration models to predict aspalathin, nothofagin and dihydrochalcone contents of dried, green rooibos, and mangiferin and hesperidin contents of dried, green Cyclopia genistoides plant material.

Rooibos tea is the common name for the plant, Aspalathus linearis spp. linearis, and its infusion. The absence of caffeine and its low tannin content compared to black tea, make it a popular herbal tea, both locally and internationally. The phenolic composition of rooibos is unique in that it contains aspalathin, a rare CC dihydrochalcone glycoside.

Honeybush is low in tannins and contains no or traces of caffeine. Until the 1990’s, honeybush tea was only consumed locally to a limited extent. The phenolic composition differs among Cyclopia species as well as types within species.

The antioxidant properties of green (unoxidised) rooibos (Aspalathus linearis) and honeybush (Cyclopia spp.) have led to an increasing interest in the development of polyphenol-enriched extracts for the nutraceutical and cosmetic industries.