What is Scoville Scale ?

Scoville Scale was created by Wilbur Lincoln Scoville who was a pharmacist in America. This was created in the year 1912 while he was employed with Parke-Davis, a Pharmaceutical company. The purpose of this scale was to measure the hotness or the spiciness of chilli peppers. He was always interested in delving into the compounds of things and his book ‘The Art of Compounding’ was used as a reference book in the pharmaceutical circles. It went on to 8 editions after being published in 1895. He also wrote a book called ‘Extracts and Perfumes’ which contained hundreds of formulas for making perfumes. He worked as a professor in Massachusetts College of Pharmacy and Health Sciences before joining Parke-Davis.

The scale he devised for testing the piquancy of the peppers was absolutely innovative and received world wide acclaim. He received the Elbert Prize in 1922 from American Pharmaceutical Association. Remington  Honor Medal was given to him in 1929 and he was conferred with an honorary Doctor of Science. This was conferred on him by Columbia University in 1929. The innovative test that he devised was called Scoville Organoleptic Scale.

When human patients test colour, texture, smell, sound and taste with their sense organs, it is known as organoleptic. It was this method that Wilbur Scoville used in testing the spiciness of peppers. So the test was known as Scoville Organoleptic Scale which was later known as the Scoville Scale test. This test measured the spiciness or pungency in the chilli or pepper. The chilli pepper belongs to Capsicum genus. The main compound which produces the spiciness in a chilli is capsaicin. The chemical capsaicin has the capacity to stimulate the chemical nerve endings on the skin. Technically it is called chemoreceptor nerve endings which are found in the skin mainly in the mucous membrane.  So this test was devised to test the concentration of capsaicin in a pepper.

The test is done by human beings. Generally there are five testers. A unit of pepper extract is mixed in sugar solution to dilute the piquancy of the pepper. When the testers cannot detect the heat then that pepper is given a Scoville Heat Unit depending on the units of sugar solution added to the pepper extract. For example for an extract of sweet bell pepper there was no sugar solution added as no piquancy was found in the extract so the Scoville Heat Unit assigned to sweet bell is zero.  At the other end, Bhutjalokia needed 1 million units of sugar solution to hide the capsaicin content in its extract.

This kind of testing has its share of problems as it depended on the taste buds of human beings. There is no standard measurement for taste buds of human tongue therefore what comes as a result from this testing is not hundred percent accurate. However, over the years scientists have developed this testing scale and tried to bring a perfect score to this testing of pepper. It is called High Performance Liquid Chromatography (HPLC). This tests the capacity of the pepper to produce heat and mathematical formulas are used to test the heat. The measurement is called ASTA pungency units. One unit of ASTA (American Spice Trade Association) pungency unit is equivalent to 15 units on the Scoville Scale. In this new test all the values is a little lower the Scoville Scale.  Scoville brought to light that some peppers are sweet and there are some varieties which can kill. But most of the peppers have moderate to high piquancy and all this was found with the Scoville Scale Test.

The extracts from the pepper showed chemicals which was the reason for the piquancy in a pepper. The highest on Scoville heat units table is Resiniferatoxin with 16 billion units. It is followed by Tinyatoxin, Capsaicin, Dihydrocapsaicin, Nonivamide, Nordihydrocapsaicin, Homocapsaicin, Shogaol, Piperine and Gingerol. At the end of the table is the chemical Capsiate with 16,000 units. There are many varieties of pepper that have any one of these chemicals in them.

Resiniferatoxin is an ingredient in chilli pepper and in another cactus like plant found in Morocco. It can desensitize people and create an irritant effect. It is toxic and can cause chemical burns. Experiments on animals have been done and it indicates that 40g or more of this in human body can cause major damage to health and can be fatal in some cases. SHU (Scoville Heat Unit) of Resiniferatoxin is 16 billion units which one thousand times higher than pure capsaicin which is the main compound tested in the Scoville Scale.

Tinyatoxin is another potential compound found in chilli pepper which is around 5 billion heat units on the Scoville Scale. This, like resiniferatoxin, is an irritant for mammals which includes human beings. It affects the nerve receptors like in resiniferatoxin. It induces a burning sensation if it comes in touch with any part of the tissue.

Capsaicin which is the third on the list of ingredients in chilli pepper with regard to potency, is the main compound found in the chilli pepper. It is this compound that is tested to form the Scoville scale. It is this compound that is diluted with sugar solutions and units found. Capsaicin is found in huge quantities in the internal membrane of the chilli, in the placental tissue and a little of it is found in the fleshy part of the chilli pepper. The seeds which are found concentrated in the inner wall do not have capsaicin. Dispersal is mostly done by birds as the seeds they consume are not broken or digested in the bird’s stomach. When the seed comes out it is fit to germinate again. The chilly also does not create any problems in the birds. Mammals cannot eat them and even if they do, the seeds are chewed up and are not fit for germination.  Capsaicin in its most potent form has 16 million heat units on the Scoville Scale. It was found that the toxin acts in the same pathway like seen in the venom of tarantula. The pathway of pain is almost same.

The study of compounds in the chilli pepper started in the mid 19th century and in 1898 Karl Micko isolated capsaicin in its purest form. Further research brought about its chemical composition or empirical formula. The research into capsaicin has helped in the use of it in food and in medicines. It is the burning sensation generated by capsaicin that excites the foodies with a taste for spicy touch. When capsaicin with high concentration is used then it can get so spicy that eyes start watering. There are people who relish that kind of taste. But the use of pure capsaicin can be very dangerous as its heat units are very high. Chilli with high heat units comes in contact with skin can cause a burning effect even if the skin is not one of the sensitive kinds. There are beverages which use capsaicin. Sauces especially chilli sauce is one of the favourite sauce in the oriental countries and this taste has caught on with the rest of the world.

The analgesic nature of capsaicin is one of the foremost findings as it has come to be used in various medicines.  It is used in nasal sprays and ointments.  The ointment which gives temporary relief from pains has capsaicin as its ingredient. Muscle pains and joint pains like arthritis will be lessened when ointment with capsaicin is used. So also pain from sprains, strains or backache can be treated by the use of this ingredient. A local anaesthesia is administered before the use of the medicine. The therapist also uses rubber gloves and a face mask. The capsaicin product is placed on the skin till the heat is felt by the patient and then it is removed. It should be remembered that the pain is felt after giving the local anaesthesia. Some studies have shown that capsaicin can deter weight regain after it is lost. There is nothing to prove that it can bring about weight loss; only acts as a deterrent in weight regain.

It is available in the form of bandages and is applied to the back. Psoriasis is treated effectively with capsaicin creams. It reduces the inflammation and itching. Since it can increase the heat in the body in a short period it can improve the metabolism. Therefore it is considered effective in regulating sugar levels. The American Association for Cancer Research has suggested that capsaicin can kill lung cancer and prostate cancer. Studies on mouse show that the treated mouse had tumour which was one fifth of the size of the tumour of the untreated mouse. It is even said to stop the growth of leukemic cells according to a study in China and Japan

There are some minor uses of capsaicin. It is an excellent pest repellent. Rabbits, voles, deer, insects, squirrels and even attacking dogs can be repelled by using capsaicin in various forms. When dried and powdered chilli is used or mixed along with the birdseed the squirrels fall prey to it and then do not destroy the food or grain or area where it is kept. Birds as we have already seen are not affected by this. It is used to repel the insects that damage the garden. It is used for bigger animals as well. In Africa it is used as crop security and this is used by the Elephant Pepper Development Trust.

It is used in riot control as we already saw. The small particles of chilli make it very difficult to breathe if it enters the nose or can be an irritant on the skin chiefly the eyes. This is a major deterrent for the assailant. There are cases where women travel with chilli powder in their handbags to make use of, in case of an attack. It is a banned element in equestrian sport. It makes the horses more active and in the 2008 Summer Olympics horses that were tested positive for capsaicin were disqualified from the meet.

As much as we know the uses and the potential danger of capsaicin it is pertinent to know about the treatment of injuries caused by capsaicin. The first and foremost is to remove the affected object and keep it in an air tight container so that it does not cause a secondary exposure. When body parts come in contact with capsaicin in any form it is better to apply oil like paraffin oil, vegetable oil, petroleum jelly Vaseline creams etc. This is especially true if the affected area is sensitive like the mucous membrane. If the heat is not too much, it can be washed off with shampoo, soap, water or any other detergent. Using plain water is not very effective. This is a simple household tip that after chopping of chilli one should wash hands with soap and water. Before long we might touch our eyes with the unwashed hand and the burning sensation caused in the eye can be unbearable. So always wash your hands with soap and water. Since capsaicin is soluble in alcohol it can be used on the affected area.

Milk, especially cold milk is another way for treating burning sensation. A sugar solution in room temperature is also good. The burning symptoms can be removed with cooling wind or with the use of ice especially in the eyes as soap cannot be used for the eyes. Have you ever tried drinking a hot beverage after eating something hot? The heat only becomes more. There are sensible home treatments like putting sugar in the mouth when something hot is consumed. This simple treatment has a scientific explanation that sugar can dilute the heat in the chilli. That is the hypothesis with which Wilbur Lincoln Scoville worked on and successful devised the Scoville Scale.

A compound as good as capsaicin, is Hydrocapsaicin. This is also an irritant but its pungency is much less. Nonivamide is next on scale is used in medicines. It is a great pain reliever. Medicines with the name Finalgon hasnonivamide as an ingredient. A drop of this creates a warm burning sensation which relieves the pain and this relief remains for several hours. Nonivamide is also called Pelargonic Acid Vannillylamide or PAVA.  It is as much an organic compound as a capsaicinoid. Like pure capsaicin it is used in the food and pharmaceutical industry. This is followed by Nordihydrocapsaicin in the Scoville table. It has about 7% of capsaicinoids and the pungency is only half of capsaicin.

With 1% of the capsaicinoids mixture, Homocapsaicin has only half the pungency of capsaicin. It is also an irritant and colourless and odourless like most of the compounds in this category. Shagaol is next on the table and is pungent and is like ginger. It is got when ginger is cooked or dried. It is more pungent than piperine but it is definitely less than capsaicin. Piperine is the piquancy found in long pepper and the black pepper. On the Scoville scale it is just before the last which is gingerol. Pepper has always been used in traditional medicines. Long before the Scoville was devised the Indians knew the heat value of pepper and used it in medicines. Gingerol is the main constituent of ginger and this is the last on Scoville scale as its piquancy is about 16,000 units. Ginger gets its name from this chemical and its uses like pepper was found many centuries before. Indians knew it was very good for digestion and have always made it a part of their food. It adds spice and aroma to the food. Its therapeutic uses are also well known in the eastern countries and latest studies are investigating its efficacy in the treatment of cancer in bowel, ovaries, pancreas and breast.

When pepper variety is taken into consideration Pure Capsiacin is on top of the table with 15 million heat units. It is followed by U.S Grade Pepper Spray, BhutJolokia, Red Savina, Habanero, Chiltepin, Cayenne, Arbol, manzano, Serrano, Yellow Hot, Jalepeno Pepper, Guajillo, Chilaca, Pasilla, Pablano, Anaheim, Chile Verde, Yellow Genetics and Red Chile. From U.S. Grade Pepper Spray the Scoville heat unit reduce till it reaches Red Chile which has a Scoville heat unit of 500-750. The last on this list is Sweet bells which has 0 units of heat on the Scoville Scale. All of them belong to the Capsicum genus but sweet bells are commonly known as capsicum in India and its neighbouring countries.

The Scoville Scale devised by Wilbur Scoville has triggered a great interest in the piquancy of peppers and the interest still continues. There are websites dedicated to chillies and lot of information is given in these sites about the types of chillies. Studies show that most of the chillies have its origin in Mexico and the nearby countries but over decades farmers and navigators have carried it around the world and today we find most of the chillies in any part of the world. There are a few countries especially in Asia where people love to spice up their food and the best way to do it is by using chilli pepper in its various forms.