engleski

Application of near infrared spectroscopy for detection of ground medicinal herbs

Medicinal plants represent a rich source of biologically active compounds that could have a beneficial effect on human health and a wide range of medicinal plants can be found on the market today. Regular or in-line particle size measurement can be one of the ways to control the quality of certain products where medicinal plants are used as raw materials for their production. The aim of this study was to examine the possibility of differentiating different particle sizes of the same plant and different particle sizes of different plants. The noninvasive spectroscopy in the near infrared range of 904 - 1699 nm (NIR) was used to record spectra of five different plants: sage (Salvia officinalis L.), thyme (Thymus serpyllum L.), lavender (Lavandula x hybrida L.), lemon balm (Melissa officinalis L.), and mint (Mentha piperita L.) for seven different particle sizes (< 100 μm, 100 μm, 250 μm, 355 μm, 500 μm, 800 μm and 1000 μm). NIR spectra were used for principal component analysis. The results showed a uniform particle size distribution for smaller fractions (< 100 μm, and 100 μm) for each medicinal plant individually, while for larger fractions the presence of smaller particles influenced the uniformity. This was confirmed by microscopic images of all the fractions. The presence of smaller particles was observed especially for 800 μm particle sizes of lavender and sage. By comparing the same particle size for all medicinal plants NIR showed very good differentiation between medicinal plants of the same particle size. Results confirm that NIR spectroscopy can be successfully used in qualitative and quantitative differentiation of different particle sizes of different plants and its very high sensitivity to different particle sizes of the same plants.

NIR spectroscopy ; Medicinal plants ; Principal component analysis ; Grinding

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