Postharvest physiological response

Freshly harvested crops of chamomile are live plant products or parts of them. They are characterized by a water content of about 80% and also by high metabolism. Therefore, the postharvest period is of decisive importance for the maintenance of excellent external and internal quality traits; it is the key for ensuring a stable and reliable quality of raw and processed chamomile products with a high standard of therapeutic and medical effects. However, our knowledge about what is happening between harvest (i.e., mowing and gathering in the field) and subsequent drying or further processing is still very poor. The physiological processes occurring in fresh horticultural crops, during the postharvest period in general, were described recently by References 9, 10, and 11 and more profoundly by Reference 8, but for medicinal and aromatic plants, and for chamomile herbs and flowers in particular, little information can be found. Recently, References 4 and 6 reported first results on the respiration activity of chamomile flowers.

The main loss factors responsible for the rapid decline of the biological quality of medicinal herb crops are characterized in Table 7.1 by Böttcher and Günther [4].

In the postharvest period respiration, senescence, transpiration, ripening, and changes in the biochemical constituents caused by the secondary metabolism were found to take place in the live product. The relationships between these processes are demonstrated in Figure 7.1.

The design of the technical lines reflects the importance of the single processes with regard to external and medical value. The external quality, important for use as tea components or powder, is largely influenced by transpirating, senescing, and ripening and by the development of harmful microorganisms. Medical values, however, are marked mainly by senescence and ripening. It is typical for medicinal crops that the loss factor "respiration" will not in all cases react directly, but mainly via transpiration, wilting, and secondary metabolism responses (Figure 7.1).

Was this article helpful?

0 0

Post a comment