The salty and acidic environment pickles the vegetables and stops any food spoilage organisms from growing. A similar process is used to make Sauerkraut, a pickled cabbage, except instead of immersing the cabbage in brine, dry salt is sprinkled over the cabbage and then packed into jars. The salt prevents most bacteria from growing except for lactobacillus that then creates an acidic environment and the combined preservative effect of salt and acidity preserve the sauerkraut for months even without refrigeration.
Meat is often cured with salt with a whole subsection of foods preserved meats called charcuterie. Curing meat with salt relies on the same principles of drawing moisture out of the meat and spoilage organisms.
However, salt alone is not safe enough for moderns food safety and hygiene. Another type of salt called a curing salt is used. This curing salt is often referred to as Prague powder or instacure. The addition of nitrates or nitrites to salt is far more effective at inhibiting bacterial growth in preserved meats. Prague powder or curing salt is a mixture of regular salt and a compound called sodium nitrate or sodium nitrite depending on the type of cure being done.
The salt is pink to differentiate it to regular table salt. Curing salts with the addition of sodium nitrate or sodium nitrate are carefully measured according to the amount of meat being cured. ACS offer a great selection of courses in all of theses areas. Under the guidance of our expert tutors, students can learn about self-sufficiency, diet, nutrition and health. If you would like to know more please get in touch with our expert tutors today - they will be happy to answer any questions, and discuss the different study choices which we have available to meet your goals.
Action of salt Salt acts as a preservative by inhibiting microbial growth. How salt is used to preserve foods Vegetables are generally preserved by pickling them in a salt and water solution brine , while meat may be rubbed with salt and dry cured or may be injected with a salt solution. Understanding more about our food Maintaining good health or yourself or others includes knowing how to prepare or store food as well as understanding the types of food that are good for you.
Culinary Herbs. This date of between and BCE is completely in line with a date proposed by Binkerd and Kolari. Despite this tantalising possibility, the actual sodium nitrate concentrations at the burial sites in the Atacama Desert has never been studied. The degree of mummification varies tremendously Aufderheide, A.
However, the reddening effect of nitrates was not mentioned until late Roman times. I first thought that what they were talking about was salt preservation generally, but the more I look at events in the Atacama desert, the more I wondered if the particular preserving power of sodium and potassium nitrate was not known from the earliest times and the discovery, focussed on its preserving power and not on its reddening effect on cured meat.
A further elaboration of what Binkerd and Kolari may have been talking about comes to us from a newspaper article. According to it, the suspicion is that prehistoric nomadic hunters in Western Asia began carrying salt containing nitrate with them to preserve the hunting catch.
The Indianapolis Star; The focus was indeed on nitrate and its preserving ability and not just on salt generally. I learned that nitrate deposits occur and precipitate as an efflorescent crust in amongst other the Egyptian and Namibian deserts, the Abu Dhabi sabkhas, and deserts of the Mojave, Death Valley and of course, the Atacama Desert and the Gobi Desert. Warren, J. It is, however, the largest desert in China, the Taklimakan Desert of Western China that offers the biggest surprise when I find the oldest examples of natural mummification in China, right in this desert region, replete with natural nitrate deposits.
The conditions are almost identical to those of the Atacama desert. Like the Atacama desert, the Taklimakan Desert is at the same time one of the aridest regions on earth and massive nitrate ore fields exist in the Turpan-Hami Basin, close in proximity to the Tarim Basin, in the Xinjiang province, where the oldest mummies in China was found. The nitrate deposits are so substantial, that an estimated 2.
Qin, Y. The initial discovery was made in by the Swedish archaeologist Bergman Folke. A set of tombs were discovered the Chinese province of Xinjiang, known as the Xiaohe Tombs. For 60 years the tombs were forgotten until in a researcher, head of the Xinjiang Cultural Relics and Archaeology Institute, found the tombs again.
The size of the area is unprecedented. So far there have been tombs found in multiple different layers. The tombs include adults and children as well as 15 intact mummies.
About half of the tombs were looted by grave robbers. It is the first time anywhere on Earth that so many mummies have been found. Among these is the body of a young female with remarkably well-preserved facial features, whose radiocarbon date indicates that she died she died about BCE.
At Hami the soil contains layers of gypsum and at Cherchen actual salt blocks are obvious within the soil, especially near the surface. Most burials are only about a meter below the surface. Aufderheide, A. Beyond the surrounding mountain ranges lie the Junggar Basin in the north and the Tarim Basin in the south.
One of these mummies may hold a further clue to their preservation. It is a white person with round eyes, perfect eyelashes, and long hair and has features that are more similar to a European person than a Chinese person.
In the Beauty of Xiaohe she, at last, had hard evidence. Unlike putrefaction, the gentle process of freeze-drying will not dislodge eyelids. It has been known from earliest times that meat curing could be done only in the winter in the absence of refrigeration. If not, the putrefying and decomposing forces would overtake the preserving action of saltpetre and decomposition would be unstoppable. It is the combination of cold and dry conditions along with the use of sodium nitrate to preserve and ordinary salt sodium chloride to aid in drying out the meat, that forms a link between the earliest forms of mummification and modern meat-curing techniques.
It seems unreasonable to think that the result of these forces, in combination, would have gone unnoticed. I further suspect that the power of these forces would have been practised in relation to fish, fowls, game and domesticated animals for centuries before they found inclusion in earliest mummification practices. The location of the Turpan-Hami and Tarim Basins are very important.
Alternatively, the northern route passes through Hami and those communities living along the Kongi and Tarim rivers that lead to Loulan and Lop Nor. It is along these routes that mummies from the Tarim Basin have been found. The caravans on the Silk Road approached Dunhuang, crossing vast sodium and potassium nitrate deposits. If the knowledge of its power was developed in this region and exported to Europe, I am sure that there should be remnants of this ancient knowledge in this city.
He believes that some of these peoples travelled west to become the Celts in Britain and Ireland, others went north to become the Germanic tribes, and still, others journeyed east to find their way to Xinjiang. These ancient European settlers are believed to represent some of the earliest human inhabitants of the Tarim Basin, and Mair has stated that from around BCE the earliest mummies to be found here are exclusively Caucasoid or Europoid rather than Chinese in origin.
The origins of the mummies have been studied extensively using DNA technology. It is however not the origin of these people who interest me as much as their destination and the destination of the traders who passed through this region.
The question is if there is any evidence that anything was done with the nitrate deposits and the clear evidence of its preserving power in the mummification. If this was the region where curing of meat was progressed into the art that we know it as today, is there any evidence of this? Any ancient document or reference, not just from China generally, but linked to this region. These were the actual questions I asked myself as I was searching.
This is not a device I employ after the fact for the sake of creating drama. Looking at the map above, the saltpetre deposits are the largest at Yuli, marked as NO Loulan is the city where many of the mummies have been found. Dunhuang is a major city before the trip past or across the desert was undertaken on the Silk Road past the Tarim Basin.
I did an internet search for any reference to saltpetre from the city of Dunhuang which would have been a key trading city in the area and important in terms of its location on the Silk Road. Not in my wildest imagination did I expect to uncover what I found! The mix of religious and secular documents date from the 5th to the early 11th centuries. One text is of particular interest to us, the Dunhuang Medical Text. In Translation, it reads as follows:. The colour of the fingernails cyanosis indicates ischaemia lack of oxygen in the tissue due to restricted blood flow.
Cold hands and feet are additional symptoms of this condition. Also, acute pain suggests that the patient may be suffering from severe angina, i.
So, at first glance, there seems to be a similarity in treatment. All three remedies contain the all important nitrate. Concerning organic nitrate, such as glyceryl trinitrate, there is a covalent bond or a molecular bond between the nitrate moieties NO3 where they share electron pairs which form the bond with the rest of the molecule CH2. Where glyceryl trinitrate relaxes the muscle lining of the artery to relax, enlarging the vessel and so allowing more blood flow, saltpetre by itself will have no effect on the treatment of angina.
Cullen, C, Lo, V. This is however not the full story. The remarkable feature of the Dunhuang text is that the combination of the use of saltpetre, not on its own, but when applied according to the dictates of the text, becomes a remedy for exactly the condition described.
It is transformed, probably in the arterial wall, into a chemical species which is the vasodilator. Under very special circumstances, exactly as detailed in the Dunhuang text, the nitrate ion from saltpetre also converts to exactly the same species which is the vasodilator. Despite the fact that glyceryl trinitrate has been in use for over a hundred years, the identity of this species has only been discovered in A very important function of the endothelium was first reported in by Furchgott and Zawadzki.
The presence of acetylcholine a small biologically active molecule in the blood stream effects vasodilation and it was generally assumed that acetylcholine acted directly upon vascular muscle. However, this was found not to be the case. It was initially assumed that it would turn out to be a complex molecule like a hormone. This speculation enhanced the surprise when the chemical nature of the molecule was finally determined.
It turned out to be a small diatomic molecule called Nitric Oxide NO. The Nobel Prize in Physiology and Medicine was awarded for this discovery. Once nitric oxide had been detected in one physiological process it was found to have roles in many others, from inflammation to crying. That it should have remained undetected during a hundred years of intense scrutiny of human physiology is astonishing. Glyceryl trinitrate is a vasodilator because it is transformed by an enzymatic process possibly by the enzyme xanthine oxidoreductase into nitric oxide.
Let us now return to the Dunhuang text. This Day In History. History Vault. Recommended for you. The Story of the Sandwich. Frozen History: The Story of the Popsicle.
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