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Tamarind and Fluoride

James Odell, OMD, ND, L.Ac.

Tamarind ((Tamarindus indica L.) is a multifunctional drought-tolerant fruit tree that has traditionally provided food, medicine, and other products. It belongs to the family Leguminosae or Caesalpiniaceae and is found throughout the tropics and subtropics of the world. The tree has become naturalized at many places particularly in India, South East Asia, tropical America, the Pacific Islands, and the Caribbean. The word "Tamarind" derives from the Arabic word "tamar hindī", which literally means "Indian date".

Tamarind is economically valuable and multi-purpose insofar as almost every part of the tree has a use, but the tree is best known for its fruit and the marketability of tamarind fruit has increased consistently over the years. The tamarind tree produces brown, pod-like fruits that contain a sweet, tangy pulp, which is used in cuisines around the world. The major production areas are Asian countries including India and Thailand, with India as the world’s largest producer of the tamarind fruit. The tamarind tree is utilized for many purposes: nutritional, medicinal, ethnoveterinary, and other.1 The differentiation among uses is based on variations in preparation (e.g., cold extraction, boiling, fermentation), application (e.g., external, internal), and product form (liquid, paste, powder).2, 3, 4

Mainly there are two varieties of tamarind found in India, including red and common brown variety. The pulp of the red variety of tamarind is less acidic in taste while the pulp of brown variety has a more acidic or sour taste. The pulp of the brown variety contains a high proportion of free acids as compared to the red variety.

Constituents

A typical fruit/pod contains about 55% pulp, 34% seeds, and 11% shell and fibers. The anthocyanin pigment chrysanthemin is responsible for the color of the pulp in case of the red variety of tamarind, and the brown color of the pulp of the brown variety is due to leucocyanidin. The percentage of the constituents varies from pod to pod with tartaric acid ranging from 8-18%, reducing sugars 25-45%, pectin 2-3.5%, and protein 2-3%. Besides being a rich source of sugars, tamarind pulp is an excellent source of B-vitamins (B1, B2, B3, B5, B6) and exhibits high antioxidant capacity that appears to be associated with a high phenolic and vitamin C content. The fruit pulp is also a good source of minerals especially potassium, calcium, phosphorus, iron, zinc, magnesium, and trace amounts of selenium and copper. Essentially, the proximate composition of the tamarind pulp depends on locality. The major volatile constituents of tamarind pulp include furan derivatives (44.4%) and carboxylic acids (38.2%), the components of which are furfural (38.2%), palmitic acid (14.8%), oleic acid (8.1%) and phenylacetaldehyde (7.5%).5, 6, 7

Processing

The pods are allowed to ripen on the tree until the outer shell is dry and can be easily separated from the pulp without adherence. The pods are then harvested by merely shaking branches of the tree. Tamarind pods contain 3 to12 seeds, which are irregularly shaped, flattened, or rhomboid. Seeds are extremely hard, shiny, reddish, or purplish brown, enveloped by a tough leathery membrane, the so-called endocarp. Outside the endocarp is the light brownish-red, sweetish, acidic edible pulp traversed by tough ligneous fibers.

Fresh-cut processing is not an industrial practice: it is usually carried out on a smaller scale when the fruits are intended to be eaten immediately. Fresh-cut tamarind is processed to make tamarind balls mixed with sugar after removing the shells, seeds, and fibers. On a large scale in processing factories, tamarind pulp is separated from the fiber and seed, then mashed with salt before being packed into bags and if tamarind is intended to be stored for a long period, drying, or freezing is required.

Cracking the pods and removing the seeds

During pre-processing, fresh tamarind fruit is subjected to sun-drying or small-scale dehydrators are sometimes used. The dry fruit is cracked, the pulp and fibers are separated, and the seeds are removed. Pods can be stored for several weeks at 20°C. Also, pulps can be stored for 4-6 months at 10°C by packing in high-density polythene. Mixing with salt can extend the storage period to one year. Tamarind juice is usually prepared by boiling tamarind pulp in water and filtering the juice to remove the pulp before pouring into bottles and sealing. Tamarind concentrate is easily dispersible in water and can be used for many purposes, such as in ketchup, sauces, soft drinks, dairy products, and as a souring agent. It is prepared by soaking the tamarind pulp in water and boiling, separating fine and pulpy matter using a filter, then pressing the residue and mixing this with the extract. The filtered extract is concentrated by evaporating it in a vacuum, filling containers, cooling, and sealing, and storing in airtight plastic or glass bottles or cans, in the dark, for over a year. Tamarind is often further processed into drinks and sweets or packaged into more convenient forms for export. In some parts of India, it is made into a jelly by mixing with water and sieving. It is then compressed into block shaped molds and can be cut like cheese when required.8