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Food Periodic Table

Food Periodic Table

Celebrating the International Year of the Periodic Table 2019 Created by Jane K Parker

Acknowledgements and thanks to the RSC Food Committee: Robert Cordina, Bryan Hanley, Taichi Inuit, John Points, Kathy Ridgway, Martin Rose, Wendy Russell, Mike Saltmarsh, Maud Silvent, Clive Thomson, Kath Whittaker, Pete Wilde, and to Martin Chadwick, Cian Moloney and Ese Omoaruhke, for contributions to the elements, to Flaticons for use of their free icons, and to Alinea and TDMA for photographs of He and Ti.

In slideshow mode, click on an element in periodic table to find out more, return via the RSC Food Group Logo.

Contact: [email protected] Periodic Table H He

Li Be B C N O F Ne

Na Mg Al Si P S Cl Ar

K Ca Sc Ti V Cr Mn Fe Co Ni Cu Zn Ga Ge As Se Br Kr

Rb Sr Y Zr Nb Mo Tc Ru Rh Pd Ag Cd In Sn Sb Te I Xe

Cs Ba La Hf Ta W Re Os Ir Pt Au Hg Ti Pb Bi Po At Rn

Fr Ra Ac Rf Db Sg Bh Hs Mt Ds Rg Cn Nh Fl Mc Lv Ts Og H 1

Occurrences in food Roles in food

• Core element in organic compounds (, , • H+ gives one of the five basic – sour. , ). • the higher the concentration of H+, the lower the pH • OH pH 2 (very sour) • H2 H2 H2 H2 H2 pH 3 (sour) C C C C C C • pH 5 (not sour) H3C C C C C C O H H H H H 2 2 2 2 2 • pH 7 Tea or (not sour) • Hydrogen-bonds, one of the strongest forms of bonding, are crucial for the 3D-structure of many • Key element in water, H2O, which is 70% of the and 70% of many . natural , e.g. proteins. • Hydrogen is used to hydrogenate to • Hydrogen bonds give water its unique properties. make it solidify, but this also gives trans fatty (TFA) as a by-product. H-bonds • TFAs are associated with cardiovascular disease and in water possibly so the WHO limits intake of TFAs to 1% of the .

It’s sour! © Royal Society of Chemistry 2019 He 2 Role in Food Chemistry Role in Food

• Important element in . • Edible helium are being served at • It is employed in techniques used extensively for food Alinea, a 3* Michelin restaurant in . testing (compositional , flavour analysis, new • They are prepared from flavoured invert product development and safety assessments). which is inflated with Helium from a cylinder. • Used as a carrier for chromatographic analysis as it is inert and unreactive. • helium used as a cryogenic refrigerant for use in superconducting magnets such as those used nuclear magnetic (NMR) instruments. • Helium is used as an alternative to in inert .


© Royal Society of Chemistry 2019 He Helium 2

Helium Beer

• Helium was a huge phenomenon in 2014 with demands exceeding supply. • Adverts showed that after a sip of beer you could sound like Donald Duck. • The press release by Stone “Stone Stochasticity Project Cr(He)am Ale with Helium” was published 1st April 2014. • Helium is not soluble in water, so technically Helium beer is impossible.

© Royal Society of Chemistry 2019 Li 3 Occurrences in food Occurrences in Drinks!

• Lithium is present in small quantities in • When 7up was invented it contained food and water. lithium citrate. • Levels in water commonly range from 2 to 7Up • The giant size bottle top proclaimed 70 ppb but some water in the “lithiated”. contains over 200 ppm. • The of grass eating contains around 5mg/kg. Lithium as a • Crustaceans and molluscs take up lithium from water and take it up from the . • Lithium citrate and lithium • A typical daily intake of lithium is around 1 are used to treat bipolar disorder. mg/day.

© Royal Society of Chemistry 2019 Be 4 Occurrences in food Role in the body

• Beryllium tastes sweet but is toxic. • It has no identified role in the body. • Beryllium is the most dangerous. • Swallowing powdered emeralds was tried as a • Those beryllium were susceptible to acute cure for the black death. beryllium through inhalation.

You are unlikely to have eaten very much – unless you have swallowed an emerald!

beryllium aluminiumcyclosilicate


© Royal Society of Chemistry 2019 B 5

Role in Food Role in the body

• Boric and tetraborate () are • Boron has an impact on parathormone. permitted in food in the EU but not the USA. • It affects the of Mg, Ca and P. • They are both only permitted as in • But Boron deficiency in humans has never caviar to a maximum of 4g/kg. been reported. • It can be used to give a rubbery texture to noodles. Occurrence in food • Boron is essential for growth. • Borate form complexes with apioses in . • Peas, , , and carrots.

Other uses

• Borax is also a ! • is used as an insecticide. © Royal Society of Chemistry 2019 C 6 Carbon is ubiquitous Occurrences in Food

• Carbon is present in all foods and drinks. • carbonate (CaCO3) is the main • The only exception is still . component of egg shells. • And even that will contain traces of . • It is used as an anticaking agent and also as an • Sparkling water contains . . • Carbon is an essential component of fats, • Sodium (NaHCO3) is soda. proteins, sugar and carbohydrates, providing the • It releases CO2 to create bubbles which make the backbone for all . cake rise. • Even flavourings are based on carbon skeletons. • Carbon black is an insoluble black food colouring. • It is formed from charred vegetable fibres – nuts, etc. • Carbon dioxide bubbles in champagne give the tingle on the tongue – this is known as chemesthesis.

© Royal Society of Chemistry 2019 N Nitrogen 7 Occurrences in food Nitrogen Gas

• Found in meat, , fish, seafood, and • Nitrogen gas is used to purge food packaging eggs, soy beans and e.g. peas. of and extend shelf . • An essential element in all plants and animals. • Cold brew coffee is pumped with nitrogen to • It is part of all amino acids, the building blocks of displace air for fresh creamy coffee. , the building blocks of life. • is used to make cream and • It needs converting to other forms such as “ effects”. , before plants are able to use it. • Guinness bubbles contain nitrogen. • is used as a supplement to increase Mm Nitrogen Compounds muscle mass.

NH O • Nitrites and nitrates inhibit bacterial growth

OH R and oxidation so are used for curing and H2N N Mm OH . O NH2 • Nitrites can react with to form nitros- Creatine Structure of Amino acids amines, so should be eaten in moderation. • Nitrogen compounds, such as pyrroles, pyrazines and contribute to the aroma of many roasty, toasty, baked foods. © Royal Society of Chemistry 2019 O Oxygen 8

Oxygen the Baddie Oxygen the Goodie

• Many foods spoil in the presence of oxygen. • Food doesn’t the same without oxidation. • This reduces and changes the colour • require the oxidation of to and alters the flavour and texture of foods. produce that yummy fried taste. • It also promotes microbial degradation as some • Oxygen containing cyclic compounds – , and moulds require O2 to grow. especially those derived from , often • such as ascorbic acid ( C) are have a sweet caramel taste.

added to food to prevent oxidation. • (O3) can be used to degrade • Oxygen scavengers can be found in sachets of residues. dried food and low moisture foods to remove O2 • Oxygen can be used in packaging to prevent the from the packet. growth of anaerobic bacteria.

OH OH O O HO 2,4-nonadienal OH OH A glucose Fried note in fries, from contains 6 oxidation of oil © Royal Society of Chemistry 2019 F 9 Occurrences in food Roles in the Body

• Found naturally in fish and tea. • Protective trace for emerging teeth and • So is added to water in parts of the UK dental maintenance, preventing . to bring the levels up to 1 ppm, mainly to • Fluoride (generally as NaF) important to protect prevent dental caries from mineral loss and inhibits of soft tissues. • Fluoride compounds e.g. fluoride added to .

Role in the Food F F F F F • Found in Teflon (tetrafluoroethylene) non stick H C C F n cookware. F F F

• Fluorinated gases are used as refrigerants, but are CF3CHF2 being phased out because they also deplete ozone. Refrigerant PTFE – polytetra- (hydrofluorocarbon) fluoroethylene

© Royal Society of Chemistry 2019 Ne 10

OK, we admit it, we can’t really do Neon……

© Royal Society of Chemistry 2019 Na Sodium 11

Occurrences in food Sodium in food

• Most dietary sodium (~75%) comes from sodium • Sodium : , tastant, flavour chloride (NaCl) added to processed foods (soups, ). enhancer, promotes Maillard browning. • : gives a savoury () taste. Roles in the body • (baking soda) is used as a raising agent in baking. • Sodium is an essential , important for nerve and muscle function. • Sodium deficiency () can cause muscle spasms and . • An excess of sodium increases pressure and increases risk of cardiovascular diseases. An excess of sodium can also cause lethargy and restlessness. Monosodium glutamate Sodium bicarbonate

It’s salty! © Royal Society of Chemistry 2019 Mg 12 Occurrences in food Roles in food

• All green leafy . • Nuts and seeds, bananas, avocado and tuna.

• Used to fortify some breakfast . N • Available as a . N Mg N

N Roles in the body O • Essential for human body - adult body O contains ~25 g, mostly in bones. O • Essential part of • in many systems so O chlorophyll (A or B) regulates many metabolic processes. O which capture • Required for production of energy. sunlight to make • Required for development of bones. leaves green. • Regulates beat and nerve impulses. • Also used as an antacid C15 (magnesium ). • Can be used as (sodium) replacement but very bitter. © Royal Society of Chemistry 2019 Al 13 Occurrences in food Roles in food

• Aluminium silicate is used as an anticaking agent ( • Aluminium pans are often used to food. powder). • Aluminium is used for food-storage and food • Aluminium is used in the “” balls used to decorate packaging (e.g. ). cakes and biscuits. • Sodium aluminium in double-acting baking • BUT biggest source is from cereals, as it taken up from powder (i.e. activation by heat rather than a simple the soil by the crops. acid- reaction) is banned in EU but permitted in • Typical adult ingests 1-10 mg of Al daily from water, the US. additives and food containers. • Aluminium “lakes” are carriers for of any colour. • They are made from aluminium (clay). • The water-soluble is co-precipitated with to make an insoluble pigment.

Aluminium lakes © Royal Society of Chemistry 2019 Si 14

Roles in food Occurrences in food

and silicates are used as anti-caking • Silicon plays an important role in agents. mineralisation and soft tissue development. • Is essential for healthy hair, and nails. Roles in food chemistry • Is found in unrefined cereals, but availability to the body can be low from -based products. • Silica is fundamental for as it is • Is found in lower levels in meat and beer, but used to support stationary phases. availability is higher. • Chromatography is important for analysing food, • Deficiency is considered a factor in the checking purity, spotting adulteration, quantifying development of . active components. Roles in

• Aluminosilicates () are used to catalyse the formation of sugar-based biosurfactants for use in the food industry. • They can also be used to filter from Aluminosilicate smoke for use in smoked foods. © Royal Society of Chemistry 2019 P 15

Role in the body Roles in food

• Is found in all cells in the body. • Phosphorus is widely used in the food • Plays a structural role in nucleic acids and industry as monophosphates, membranes. diphosphates of . • Is an essential mineral for growth and • Phosphates are used as stabilisers and repair. emulsifiers. • Essential for bone . • They hold onto water in meat products. • Phosphorus from sources is more • Interact with proteins in processed easily absorbed than from plant sources. . • Deficiency is called hypophosphatemia and • Inhibit growth of spoilage organisms in causes , and bread. . • Riboflavin phosphate is a label-friendly alternative to synthetic colours. • Phosphoric acid is present in many soft drinks. • However it weakens .

© Royal Society of Chemistry 2019 S 16 Occurrences in food Roles in food

• Proteins (S-containing amino acids are cysteine and • used as fertiliser to improve crop quality. methionine). • Disulfide bonds between cysteine residues hold • Particularly eggs, meat, coffee, vegetables. proteins together. • Sulfur compounds responsible for aroma of , • Disulfide bonds in gluten essential for stabilisation of leeks, and the compound that makes you cry. bubbles in bread.

• Glucosinolates in brassica (broccoli, sprouts, etc.) have • SO2 is used as a preservative e.g. in wine, dried . potential anticancer properties. • Variety of sulfur compounds contribute to the aroma • They break down to which give an of foods, particularly savoury aromas. acrid mustardy flavour. O O S O H2S meaty eggy smell SH smell - O Cl + S N N H3C S OH N NH2 lachrymator in onions thiamine - Vitamin B1 more Sulfur compounds stink! © Royal Society of Chemistry 2019 S Sulfur 16 Role of glucosinolates in Brassica R S glucose N - In of OSO3 • glucosinolate the plant cell • In of • Non-volatile the plant cell myrosinase glucose • Can have bitter

R S taste H N - OSO3 glucosinolate O S N C S

• Anticarcinogenic R N C S R C N Sulforaphane • Volatile isothiocyanates nitriles Active component • Pungent, aroma in brassica R S C N C N thiocyanates S R' epithionitriles


S oxazolidene-2-thiones © Royal Society of Chemistry 2019 Cl 17 Occurrence in Food Role in the Food Industry

• Only found combined in , with other elements • Chlorine kills bacteria and other microbes and is a such as sodium as NaCl in table and salt. disinfectant used by the water industry. • Found in seaweed, , tomatoes, , , • Major use as antibacterial agent to clean kitchen olives and prepared foods. surfaces and utensils. • This powerful disinfectant is used to chickens in Role in the Body the US. It poses no harm, but may cover up unhygienic • Chloride ions regulate fluid in and out of cells living conditions and poor poultry management. and are essential to life. • Chlorinated compounds are often responsible for off • HCl is required in the stomach to digest food. notes and taints on food. • Plays a role in perception of salty taste in • Trichloroanisole (TCA) is responsible for the “corked” combination with Na+. note in wine. • 2,6-Dichlorophenol has a disinfectant note which can OCH3 be detected at 4 ppb. Cl Cl


© Royal Society of Chemistry 2019 Ar 18

Roles in food

• Argon is used as an alternative to nitrogen in inert food packaging gases. • It is heavier than nitrogen so it more readily displaces oxygen. • High pressure Argon (4MPa) has been used to pretreat slices prior to refrigerated storage under nitrogen. • Moisture, colour and were all maintained for longer, and fewer microbes were detected.

© Royal Society of Chemistry 2019 K 19 Occurrences in food Roles in food

• Avocados, starchy roots and tubers. • Potassium occurs naturally in most fruit and • Bananas, citrus . vegetables in the form of phosphate, sulfate • Leafy vegetables, legumes. and citrate salts. • Whole , dairy products. • , KCl tastes salty so it is used to partially replace sodium chloride in salt replacers, but tastes bitter and metallic. Roles in the body • Potassium hydrogen sulphite( E228) used to inhibit in wine. • Vital mineral and electrolyte for the body. • Can be used in functional roles: baking • Helps regulate . powder KNaC4H4O6 (E337), pH control and protein modification. • Promotes muscle and nervous system • Largest use of potassium is as a plant function and brain health. fertiliser. • Helps removal of excess Na to reduce (K & Na ions flow in cells). • Adequate intake (AI) 3,500 mg/day.

© Royal Society of Chemistry 2019 Ca Calcium 20

Occurrences in food Role in Food

• Dairy products, green leafy vegetables and fish. • Calcium is necessary for formation of micelles in milk. • During cheese making, the pH is lowered to make the micelles aggregate and form curds. • Goats milk is less rich in calcium, so is sometimes added to strengthen the curds. Role in the Body • is a permitted colour in food (white). • It is also added to breakfast cereals and non-dairy • Promotes strong bones and teeth. to boost calcium intake. • Calcium chloride is used in canned vegetables to keep Submicelle them firm and also to condition dough in bread-making.

Peptide chains • It forms cross links with alginates to form beads.

Calcium phosphate • One use of these beads is to create bubbles which burst to give flavour in fancy cocktails. Casein micelle

© Royal Society of Chemistry 2019 Sc 21

Occurrences in food

• Rare found at very low levels in food and in nature. • No known effects on the body.

© Royal Society of Chemistry 2019 Ti 22

Occurrences in food

(TiO2) is mined from the earth. • It is used as a whitening agent in chewing gum, icings and decorations. • It makes foods look more vibrant. • It is not readily absorbed by the body. • It has no nutritional value. • Also used as an anti-caking agent.

© Royal Society of Chemistry 2019 V 23

Occurrences in food

• The best food sources of vanadium are , shellfish, , parsley, dill weed, beer, wine, and grain products. • Evidence that it is essential for humans is only circumstantial. • Vanadium has shown some therapeutic effect against diabetes. • Organic complexes of vanadium better absorbed than the inorganic forms. • The vanadium complex amavadin accumulates in fly agaric mushrooms making them toxic.

© Royal Society of Chemistry 2019 Cr 24

Occurrences in food Role in body

and preserves contain the highest levels of • Tri-valent chromium Cr(III) or Cr3+is essential to chromium and are the largest source of dietary human life and plays an important role in exposure. , and protein metabolism. • Vegetables, egg , whole grains, meat, dairy and • Helps with blood sugar control. fruit. • However, hexavalent, Cr(VI) or Cr6+ is toxic.


• In the early , dichromate was used to colour bakery products.

© Royal Society of Chemistry 2019 Mn 25

Occurrences in food Role in body

• Both nutritionally essential and potentially toxic! • An essential element that is present in most foods, • Is key for the formation and function of one of the particularly green vegetables. most important antioxidants in the body. • Highest concentrations are found in nuts. • Required for healthy cartilage and bones. • Beverages, cereals and bread make the highest • Co-factor for many different . contribution to the dietary exposure due to the larger • Provides proline for formation in skin cells. amounts consumed. • Absorption decreases if supplements are used. • Manganese aspartate, manganese ascorbate, manganese pidolate and manganese bisglycinate can be used in dietary supplements.

© Royal Society of Chemistry 2019 Fe Iron 26

Occurrences in food Role in the Body

• In meat, fish, liver and egg yolk, iron is present as • Iron helps form red blood cells, provides oxygen and haem iron (haemoglobin) and is readily absorbed. aids in the of oxygen to all parts of the body. • In plant sources i.e. dark green vegetables, legumes, • It is required to convert nutrients to whole grains, it is present as non-haem iron. triphosphate (ATP) during cellular respiration, thus • Recently, a company producing plant-derived burgers providing energy for the body. have isolated a plant based haem iron (leghaem- • It supports good immunity and cognitive function globin) found in the root nodules of soya, to mimic • Bioavailability is increased when iron is chelated to an the colour and flavour changes in meat. amino acid such as to form ferrous glycine. • It changes to brown when cooked. • , and are sometimes fortified with Iron (II) lactate, fumarate or succinate.

Are you getting enough?

Iron (II) lactate Iron(II) sulphate Iron (II) fumarate

© Royal Society of Chemistry 2019 Fe Iron 26

Are you eating enough Iron?

• Iron is essential for good health in humans. However, the following groups are more prone to inadequate levels of iron and defects such as deficiency anaemia, thus may require particular attention and perhaps higher levels of iron compared to the generic requirements (which is ~10mg a day): • Children require more iron as it is necessary for their growth. • Females 11-49 years loose iron especially due to menstrual blood loss, and lactation. Pregnant women may need to consumer higher amounts of iron-rich food. • Older adults may be at risk of higher iron losses due to gastrointestinal diseases and medication usage • Athletes may loss iron through increased sweat, urine, gastrointestinal blood loss and destruction of blood cells as a result of physical impact. • Consuming diets that are low in both haem and non-haem iron increase the risk of complications for iron deficiency. • However, ingesting excess iron from can be dangerous.

© Royal Society of Chemistry 2019 Co 27 Occurrences in food Role in body

• Found in fish, nuts, leafy green vegetables, such as • It is a key component of vitamin B12 and is required broccoli and spinach, and cereals, including oats. for the synthesis of haemoglobin. • Vitamin B12 binds with a salivary intrinsic factor History (haptocorrin) under acidic condition in stomach as a • Cobalt deficiency has been a concern historically in part of its absorption process. Thus those with low farm animals, e.g., “bush sickness” in New Zealand stomach acid secretion and who are taking anti-acid which was cured by adding cobalt to the fertilisers. medication have higher risk of B12 deficiency. • Cobalt chloride was used in in the 1960s as a • Cobalamin deficiency in humans is a realistic concern foam stabiliser in beer. for vegans and vegetarians. • This predisposed regular drinkers to heart attacks. • It is becoming a major concern in patients who have undergone weight-loss surgery. Their follow-up nutritional counselling focuses on providing absorbable forms of cobalamin, e.g. as nasal sprays.

© Royal Society of Chemistry 2019 Ni 28

Occurrences in food

• Nickel is present in most foods. • Concentrations of nickel are high in nuts. • But beverages and cereals contribute the most to dietary exposure due to larger consumption.

© Royal Society of Chemistry 2019 Cu 29 Occurrences in food Role in Body

• Copper is an essential element with food being • Required for activity of range of enzymes the major source. needed for a huge range of essential • Copper is found at highest concentrations in metabolic functions:- offal, shellfish, and nuts, but cereals and bread • Iron transport are the highest sources of exposure due to the • transport in respiratory larger amounts of these foods that are reactions consumed. • Melanin and pigment production • 20-25% of copper intake from drinking tap water. • Growth and production of nervous tissue • 50g of high cocoa can contain • Protection against free radical damage RDA of copper (900 µg). • Growth and development of bones and • Copper is antibacterial, used to be used in connective tissue hospitals in door handles and plates to reduce • Healthy function transmission of . • Copper deficiency can to neural dysfunction, osteoporosis, blood, bone and connective tissue disorders.

© Royal Society of Chemistry 2019 Zn 30

Occurrences in food

• Zinc is an essential element for human health, and is present in plants and animals. • It is essential for the functioning of insulin. • It is a key component of > 200 enzymes many of which are important in human metabolism. • Zinc is found at highest concentrations in meat. • Bread, cereals, meat, meat products and milk are the major contributors to the dietary exposure. • Normal dietary exposures is unlikely to be of toxicological concern.

© Royal Society of Chemistry 2019 Ga 31

Occurrences in food

• Found in low levels in the body • Not harmful. • No known role in the body.

© Royal Society of Chemistry 2019 Ge 32

Roles in food

• Trace element. • Found in many healing herbs such as , and aloe vera. Also in broccoli, celery, garlic, shitake mushrooms, milk, onions, rhubarb. • Germanium has been reported to improve the immune system, boost the body’s oxygen supply, but little scientific evidence. • In fact the US FDA concludes that use of germanium as a nutritional supplement presents potential health .

© Royal Society of Chemistry 2019 As Arsenic 33 Occurrences in food

• Inorganic arsenic is present in drinking water in • One of the first chemicals classified as a Group I contaminated regions. . • Inorganic arsenic of rice can be a big • Inorganic acid is more toxic than organic arsenic. problem. • Toxicity can lead to skin, lung and bladder • Vegetables can also be a source of inorganic arsenic. . • Organic arsenic, which is less toxic then the inorganic • Toxicity can also lead to metabolic, form, is found in fish and seafood. developmental and cardiovascular disorders • Tetraarsenic tetrasulfide (realgar) exists as a bright red and was traditionally mixed with rice liquor and drunk during the Chinese Dragon Boat Festival. arsenite arsenate realgar O arsenobetaine + As - (most common O form of arsenic in seafood)

© Royal Society of Chemistry 2019 Se 34 Occurrences in food Roles in the body

• Plant foods especially provide much • Occurs in nuts, wholegrain products, and in of the Se in the diet. brown rice. • Plays a key role in the thyroid which • Also found in poultry and seafood. produces hormones affecting mood. • Onions, garlic, mushrooms. • that works with to protect cell membranes. • Required for the production of , most important antioxidant. • Trace mineral essential for strong immune systems. • Selenium enters food chain via soil during growth. • Recommended RDA 55µg. • It occurs as selenium analogues of Sulphur-

containing amino acids. O O • Selenomethionine is available as a dietary Se supplement (selenium yeast). OH HSe OH

NH2 NH2 selenomethionine selenocysteine

Like Sulfur, Se-compounds stink! © Royal Society of Chemistry 2019 Br 35

Occurrences in food

• Found naturally in earth’s crust and . • In the US, is added to for bread making. • It makes the dough more elastic. • Bromophenols are important for the flavour of crustaceans. • They have a medicinal taste which is perceived as an off-note. • but at low levels impart a “marine-like” or “iodoform” quality. • Bromate is regulated in drinking water.

OH OH OH OH OH Br Br Br Br Br Br r

Br Bromophenols in crustaceans. Br Br

© Royal Society of Chemistry 2019 Kr 36

Occurrences in food

• Rare odourless tasteless gas.

© Royal Society of Chemistry 2019 Rb 37

Occurrences in food

• No known toxicity or deficiency for Rubidium. • No known role in body. • Present in earth’s crust so present in water and absorbed by crops.

© Royal Society of Chemistry 2019 Sr 38

Occurrences in food Role in the Body

• Strontium is a mineral found in seawater and soil. • can increase bone formation • The main soured in the body is seafood. and prevent bone loss due to osteoporosis. • It is also found in whole milk, wheat bran, meat, poultry, and root vegetables. • Strontium citrate is available as a supplement. Sr2+ O - O -O O


O - O O -O Sr2+ Strontium ranelate

© Royal Society of Chemistry 2019 39 to Row Transition 48

39 Y 44 Ru 40 Zr 45 Rh 41 Nb 46 Pd 42 Mo 47 Ag Silver 43 Tc Technetium 48 Cd

Role in food Three examples

• Generally the most stable of the transition metals. • Rarely occur in food and are relatively inert. • Very few have a role in the body. Mo Ag Cd • However, some are toxic and regulated.

© Royal Society of Chemistry 2019 Mo Molybdenum 42

Occurrences in food Role in the body

• Highest concentrations are found in nuts and offal, • A component of enzymes needed for and dark green vegetables. metabolism. • Cereals and Bread are the main sources of exposure • Instrumental for iron storage in the due to the higher consumption of these foods. body and production of . • Plant material grown above ground contains higher • Deficiencies of this mineral are rare concentrations of molybdenum compared with foods from tubers or animals. • A relatively rare element and an essential constituent of several enzymes in the human body.

© Royal Society of Chemistry 2019 Ag Silver 47

Occurrences in food Role in food

• Silver is a permitted additive in the EU under Annex • While silver itself is not toxic, most silver salts are II of Regulation 1333/2008. poisonous. • It is permitted for use as a coating on confectionery • Intake of silver is estimated at about 2 micrograms/kg and as small particles in alcoholic drinks. bodyweight/day from food and water • Unfortunately a considerable proportion silver • Excess intake of silver, either as colloidal silver or from wrapped have been shown to be working in an where there is silver dust, wrapped in aluminium, which is not a permitted produces argyria, a condition where the skin turns additive, rather than silver. grey or blue-grey. • Silver is available as foil and wire at purity up to 99.998%. History

• Herodotus records that water was stored in vessels made of silver in order to keep it fresh.

© Royal Society of Chemistry 2019 Cd Cadmium 48

Occurrences in food Role in food

• Crop plants readily absorb cadmium from • Problems caused by cadmium exposure the soil. through food are extremely rare. • For non-smokers, the major sources of • As cadmium is a naturally occurring cadmium are vegetables, grains and tubers, heavy , which is toxic at high due to the large quantities consumed. doses, it is highly restricted by food • Other foods that include high concentrations legislation. of cadmium are shellfish and offal such as • Studies have shown that around 5% of and liver. the population may exceed the • There has recently been concern over levels European Authority of cadmium in chocolate and cocoa recommended limits of 2.5μg/kg body products, as we eat a lot. weight, however this limit is 10% of that set by the WHO (World Health Organisation) at 25μg/kg.

© Royal Society of Chemistry 2019 In 49

Occurrences in food

• The biological role of indium is unclear. • Some people believe it is essential for human health. • So indium sulfate is sold as a dietary supplement. • It may enhance the absorption of other .

© Royal Society of Chemistry 2019 Sn Tin 50

Occurrences in food

and are two well-known alloys of tin that have been used to make dishes and other culinary equipment. • Tin cans have been used for food for nearly 200 years and these cans are made from sheets with a coating of tin to prevent rusting. • Canned foods contained higher concentrations of tin presumably as a result of the slow dissolution of the tin coating. • Normal dietary exposures to tin are unlikely to be of toxicological concern. • Tin oxide is used to make edible decorations for confectionary.

© Royal Society of Chemistry 2019 Sb 51

Use in Food Industry

similar Arsenic • (Sb2O3) is used as a catalyst during the manufacture of PET.

• Sb2O3 can migrate into food from PET packaging. • Controlled by Food Adulteration Regulations.

© Royal Society of Chemistry 2019 Te 52

Occurrences in food

• Rare element present in the earth’s crust. • Low levels present in the food chain as a result.

© Royal Society of Chemistry 2019 I 53

Occurrences in food Role in the Body

• Widely found in foods such as fish and seafood, • can lead to an enlargement of the seaweed, dairy products and products made from thyroid, seen as a swelling of throat area. grains. • Important mineral for production of thyroid • Main sources seaweed ( kelp), white fish, milk and hormones which help regulate metabolism and yoghurt. development of babies’ brains during pregnancy. • Sometimes added to salt to prevent iodine deficiency • EFSA RDA for iodine is 150mcg / day for adults . disorders. Although this is not common in the UK. • Iodine supplements mainly for pregnancy use • The main component of the red food colouring potassium , . erythrosine is iodine.


• Iodine is used to disinfect cows’ udders before milking.

© Royal Society of Chemistry 2019 Xe 54 Use in Food Industry

• Pulsed Xenon flash treatment has been shown to inactivate 13 food-related . • It could inactivate food poisoning bacteria.

© Royal Society of Chemistry 2019 Cs 55

Occurrences in food

• Natural occurring cosmic and terrestrial means that some Caesium enters the food chain. • It is only present at low levels. • It has relatively low toxicity

© Royal Society of Chemistry 2019 Ba 56

Occurrences in food

• Some food accumulate significant amounts of Barium from the soil. • Barium may be found in Brazil nuts, seaweed, fish, and certain plants. • The amount of barium found in food and water usually is not high enough to be a health concern. • Vegetables and grains take up Barium from the soil and this is the major source in the human body (22mg per person).

© Royal Society of Chemistry 2019 57 to 71

57 La 65 Tb 58 Ce 66 Dy 59 Pr Praseodymium 67 Ho Holium 60 Nd 68 Er 61 Pm 69 Tm 62 Sm 70 Yb 63 Eu 71 Lu 64 Gd

Role in food

• Rarely occur in food.

© Royal Society of Chemistry 2019 72 to Third Row Transition Metals 80

72 Hf 77 Ir Iridium 73 Ta 78 Pt 74 W 79 Au Gold 75 Re 80 Hg 76 Os

Role in food Two Examples:

• Rarely occur in food and are relatively inert. • Very few have a role in the body. Au Hg • However, some are toxic and regulated.

© Royal Society of Chemistry 2019 Au Gold 70

Edible Gold Glitter – is it real gold?

• The gold glitter used to decorate most eggs, cakes, and confectionary is a mixture of brown colouring, titanium oxide and iron oxide. • However, 23 ct edible gold leaf is available (£200/g) for food use. • Gold is inert and passes through the body unchanged.

© Royal Society of Chemistry 2019 Hg Mercury 80

Occurrences in food

• The sources of mercury contamination are environmental, industrial and agricultural. • Exposure to mercury is mainly from the diet and dental . • Mercury can exist in inorganic and organic forms in food. • The organic forms, such as methylmercury, are more toxic following ingestion. • Highest concentrations of mercury are found in Offal, Fish, and some vegetables • Fish is the major contributor to dietary exposure.

© Royal Society of Chemistry 2019 Tl 81

Occurrences in food

• Thallium compounds are naturally present in the environment, in air, water and soil. • Mainly formed as a result of . • Can sometimes accumulate in food in contaminated areas. • Thallium Is toxic. • In the USA, the is set at 0.00001kg/kg bodyweight/day.

© Royal Society of Chemistry 2019 Pb Lead 82

Occurrences in food

• Lead is naturally present in the environment, in air, water and soil. • It enters the food chain via crops which absorb lead from the environment. • Offal has the highest lead concentration. • However the greatest contributions to dietary exposure is from beverages, bread and some vegetables. • Adverse effects resulting from normal dietary exposure are likely to be very small.

© Royal Society of Chemistry 2019 Bi 83

Occurrences in food Role in the body

• Occurs naturally in low concentrations in • Not essential for the body. tubers, roots and sea vegetables. • No nutritional benefits. • Present in Pepto-Bismol which relieves • Pepto-Bismol reduces acidity and may absorb symptoms of , indigestion and . diarrhoea. • But in higher doses it is toxic.

© Royal Society of Chemistry 2019 Po 84

Occurrences in food

• Doesn’t occur naturally in foods. • Radioactive metal present in the crust and therefore also in seawater. • There is some concern that these radioactive metals may be concentrated in kelp. • They may be chelated by the surface bacterial slimes on kelp. • However research shows that the quantities that may enter the human food chain as a result, are so low as to not pose a danger to human health.

© Royal Society of Chemistry 2019 As 85

Occurrences in food

• Rarest of the naturally occurring elements. • Only 1g exists at any time. • Highly radioactive. • Not present in food. • Potential use in radiotherapy.

© Royal Society of Chemistry 2019 Rn 86

Occurrences in food

• Doesn’t occur naturally in foods. • Radioactive . • High exposure (e.g. in mines) to an increase in the incidence of lung cancer. • Naturally occurring low levels are emitted from the ground. • Can sometimes occur hot springs, and spring water.

© Royal Society of Chemistry 2019 89 to 103

89 Ac Actinium 97 Bk 90 Th 98 Cf 91 Pa 99 Es 92 U 100 Fm 93 Np 101 Md 94 Pu 102 No 95 Am 103 Lr 96 Cm

Role in food

• Rarely occur in food, and only do so as a result of contamination.

© Royal Society of Chemistry 2019 87 to Bottom Row 118

87 Fr 110 Ds 88 Ra 111 Rg 89 Ac Actinides 89-103 112 Cn 104 Rf 113 Nh 105 Db 114 Fl 106 Sg 115 Mc 107 Bh 116 Lv 108 Hs 117 Ts 109 Mt 118 Og

Role in food

• Never occur in food.

© Royal Society of Chemistry 2019