Benders'dictionary of nutrition and food technology

256iodopsin See rhodopsin.IoM Institute of Medicine of the US National Academies; website http://www.iom.edu/.ion An atom or molecule that has lost or gained one or more electrons,and thus has an electric charge. Positively charged ions areknown as cations, because they migrate towards the cathode(negative pole) in solution, while negatively charged ions migratetowards the positive pole (anode) and hence are known asanions.ion-exchange resin An organic compound that will adsorb ionsunder some conditions and release them under other conditions.The best-known example is in water softening, where calciumions are removed from the water by binding to the resin, displacingsodium ions. The resin is then regenerated by washingwith a concentrated solution of salt, when the sodium ionsdisplace the calcium ions. Ion-exchange resins are used forpurification of chemicals, metal recovery, a variety of analyticaltechniques and treatment of hypercholesterolaemia.ionisation The process whereby the positive and negative ions ofa salt or other compound separate when dissolved in water. Thedegree of ionisation of an acid or alkali determines its strength(see ph).ionising radiation See irradiation.IQB (individual quick blanch) Steam blanching method inwhich all particles receive the same heat treatment, unlike conventionalsteam blanching where particles at the periphery of thebed are overheated when those in the centre are adequatelytreated.IQF Individual quick frozen or freezing.Irish moss A red seaweed, Chondrus crispus; source of thepolysaccharide carrageenan.Composition/100 g: water 81 g, 205 kJ (49 kcal), protein 1.5 g, fat0.2g, carbohydrate 12.3g (0.6g sugars), fibre 1.3g, ash 4.7g, Ca72 mg, Fe 8.9 mg, Mg 144 mg, P 157 mg, K 63 mg, Na 67 mg, Zn2mg, Cu 0.1mg, Mn 0.4mg, Se 0.7µg, vitamin A 6µg RE (71µgcarotenoids), E 0.9 mg, K 66.9 mg, B 1 0.01 mg, B 2 0.47 mg, niacin0.6 mg, B 6 0.07 mg, folate 182 µg, pantothenate 0.2 mg, C 3 mg.iron An essential mineral.The average adult has 4–5g of iron, ofwhich 60–70% is present in the blood as haem in the circulatinghaemoglobin, and the remainder present in myoglobin inmuscles, a variety of enzymes and tissue stores. Iron is stored inthe liver in ferritin, in other tissues in haemosiderin, and in theblood transport protein transferrin.Iron balance: losses in faeces 0.3–0.5 mg per day, in sweat andskin cells 0.5 mg, traces in hair and urine, total loss 0.5–1.5 mg per