Library | ||||
|
||||
Herbs In Africa
Dehydration
Dehydration as an art is very old, the origins
of which are lost in time. As a science it is relatively young being
less than 100 years old. As a process it is fundamental to most herb
growing operations. The Benefits of Dehydration The ownership of a dehydrator confers upon the herb grower a degree of market flexibility which is unmatched by any other branch of horticulture. Some of the benefits are as follows:
The Aim Of Dehydration Good dehydration practice seeks to preserve the herb metabolites in as near to their natural state as possible. Therefore the water content of the material must be quickly and efficiently reduced to a level where biochemical reactions cease and micro-organisms are unable to function. The temperatures employed must be so regulated that the metabolite and cosmetic integrity of the material is not damaged, therefore the grower must not only have knowledge of dehydration theory and the apparatus employed but must also understand the characteristics of the material upon which they work. The Living Herb As living entities herbs are incredibly complex. A single cell with the addition of a few basic elements can manufacture in seconds a dazzling array of intricate compounds, even one of which could take a modern research laboratory many years of painstaking work to reproduce, if indeed they could be reproduced at all. It is well that we remember that the chemical expertise demonstrated by a single blade of grass is as yet beyond our knowledge. Photosynthesis
The word 'photosynthesis', means literally,
'made from light' and by that ultimate transmutation the green plant may be
seen as the supreme planetary alchemist. The green plant alone has
mastered the secret of the transmutation of sunlight, water and carbon
dioxide into food. All life forms are dependant on the power of the
leaf. Primary and Secondary Compounds Primary compounds such as carbohydrates, proteins, lipids and nucleic acids are to be found in all living organisms, whereas the natural distribution of the secondary compounds such as alkaloids and glycosides etc, is somewhat more sporadic, however the secondary compounds are produced in great variety by the green plants. Several thousand of them have been identified, what is surprising is that they have been synthesized from just 6 major chemical groups, yet they are able to elicit all known pharmacological responses. General Plant Metabolism
Metabolism is the term applied to the sum
total of chemical activity that occurs within the plant. Herbs like humans
must eat, drink, respire, reproduce and die. Water as the arbiter of life
performs the same function within the herb as does the blood stream within
the human system. The plant is able to exercise a high degree of control of
the water throughout its system. When the weather is hot and water
plentiful, its rate of transpiration is rapid. Experiments have shown the
metabolic rate of an organism is considerably increased by a rise in the
temperature, the rate of many reactions being doubled by a 10�C rise.
The herbs, stem and upper surface of its leaves are
covered in much the same way as human skin with thousands of tiny pores
called stomata (pl.). the stoma may be opened or closed by 2 sickle shaped
guard cells, which line the edges of the stoma.
The stomata are normally open during daylight
hours and closed at night, however they will also close if the plant
is in anyway damaged or subjected to environmental stress. Enzymes, the plant chemists
Enzymes are classed as complex proteins and
nearly all chemical reactions that occur within a living organism are
ordered by enzymes. Dehydration Times and Temperatures.
The water content of the freshly harvested
herb must be swiftly and efficiently reduced to 8 or 9% of its total, at
which point enzyme activity will cease, the herbal material may then be
considered stable. Dehydration, Basic Information Differing species of herb exhibit differing characteristics not only in shape and form but also in the structural composition of its parts, eg soft, hard, fleshy, dense, fibrous, waxy, thick, thin etc; all of which may be considerably modified by geo-climatic factors which will vary from site to site, therefore it is not possible to raise the treatment of any specie to the level of dogma. Good dehydration practice is as much an art as it is a science and because of the considerable number of variables involved it has not been possible to reduce the practice to a series of tidy mathematical equations. The human mind can weigh and judge imponderables, then arrive at a working solution, therein lies the art. Therefore the operator of dehydration equipment must temper the science with observation and experience. Library
The Pharmageddon Herbal
These articles have been published in Science
in Africa
|