Browsing by Subject "jodi"

The aim of this Master’s Thesis was to develop a method for determining iodine from food. The method was developed and validated for the Finnish Food Safety Authority Evira. The literature review focused on the chemistry of iodine and its occurrence in nature and food as well as its physiological importance to humans. Different methods used in iodine analyses were also discussed with emphasis placed on ICP-MS. Sample matrices used in the experimental study were milks with different fat contents, egg, cheese and fish. Two different milk powders (BCR®-150 and BCR®-063R) and fish muscle (ERM BB®-422) were used as certified reference materials. Milk and cheese samples were dissolved in 0.5 % ammonium hydroxide, left overnight and shaked for two hours before the analysis. Cheese and fish samples were prepared using microwave digestion with ammonium hydroxide as the reagent. After both sample preparation methods the samples were in 0.5 % ammonium hydroxide which was also used as the rinsing solution of the ICP-MS-instrument. Tellurium was used as an internal standard. Validation parameters determined were method specificity, selectivity, repeatability, reproducibility, accuracy, measuring range, linearity, LOD and LOQ. Measurement uncertainty of the method was also estimated. The method was proven to be specific and selective to measure iodine. The accuracy of the method for egg and milk samples was 90.3% and the recovery of added iodine in these samples was 98.7%. For the fish and cheese sample method these results were 86.9% and 102.3%. Both sample preparation methods gave repeatable and reproducible results. LOQ for the milk and egg sample method was 0.02 mg kg-1 and for the fish and cheese method 0.06 mg kg-1. The expanded measurement uncertainty for all matrices was 10–29%. The validation proved the method to be fit for purpose and reliable. The method will be used for measuring the iodine content of actual food samples.

Suomessa valtion ravitsemusneuvottelukunta suosittelee jodioidun ruokasuolan käyttöä teollisuudessa väestötasolla havaitun lievän jodin puutoksen takia. Epäily jodin vaikutuksesta elintarvikkeiden aistittavaan laatuun on nähty käytön esteenä. Tästä syystä tutkielmassa selvitetään jodioidun ruokasuolan vaikutuksia ruoan aistittavaan laatuun. Kirjallisuuskatsauksessa perehdytään aikaisempaan tutkimustietoon jodioidun ruokasuolan vaikutuksista elintarvikkeiden aistinvaraisiin ominaisuuksiin. Lisäksi tarkastellaan jodin pysyvyyttä elintarvikkeissa. Kokeellisen työn tutkimusmateriaalit olivat lauantaimakkara, leipä ja säilykekurkku. Materiaalien NaCl-pitoisuudet olivat 1,72 %, 1,20 % ja 1,70 %. Jodipitoisuudet jokaisessa materiaalissa olivat 0 mg, 25 mg, 50 mg ja 100 mg kilogrammassa ruokasuolaa. Jodi lisättiin elintarvikkeisiin valmistuksen yhteydessä kaliumjodidina (KI). Aistinvaraisissa arvioinneissa käytettiin poikkeama vertailunäytteestä -menetelmää, jossa koulutettu 12 henkilön raati arvioi materiaalien hajua, makua, suutuntumaa, ulkonäköä ja rakennetta. Raadin avulla luotiin tutkimuksessa käytettävä arviointisanasto. Arvioinneissa jokaista näytettä verrattiin jodioimattomaan näytteeseen. Arvioinneista tehtiin neljä toistoa. Tutkimusmateriaalien jodin hävikki määritettiin kemiallisten analyysien avulla Elintarviketurvallisuusvirastossa. Havaitut aistinvaraiset muutokset vertailunäytteeseen nähden olivat pieniä kaikissa jodipitoisuuksissa. Suositusten mukainen määrä jodia ruokasuolassa, 25 mg/kg, ei aiheuttanut tutkittaviin elintarvikkeisiin aistinvaraisia muutoksia. Suuremmat jodipitoisuudet aiheuttivat lauantaimakkarassa tilastollisesti merkitseviä eroja leikkautuvuudessa ja värissä. Kuluttajan voi kuitenkin olla vaikeaa huomata jodin aiheuttamia muutoksia lauantaimakkarassa, koska erot vertailunäytteeseen olivat pieniä. Jodin hävikki vaihteli elintarvikkeen mukaan. Lauantaimakkarassa hävikki oli suurimmillaan 14 % ja leivässä 24 %. Säilykekurkuissa hävikki oli suurimmillaan 54 %. Tulosten perusteella jodioitua ruokasuolaa voidaan käyttää tutkitun tyyppisissä elintarvikkeissa ilman, että merkittäviä aistinvaraisia muutoksia syntyy. Tulokset tukevat aikaisemman kirjallisuuden havaintoja. Yhdistäen tutkielman tulokset kirjallisuuden tietoihin jodioidun ruokasuolan käytölle elintarviketeollisuudessa ei ole aistinvaraista estettä. Hävikin ja ruokasuolan vähentämistavoitteiden valossa voidaan jodipitoisuuden lisäystä ruokasuolassa suositella. Jodipitoisuuden korottaminen ruokasuolassa olisi tehokas tapa nostaa väestön jodin saantia ilman että ruokasuolan saanti nousee.

Iodine deficiency is a global health problem that causes physical and mental development disorders in humans. School-age children, pregnant women and consumers of organic food are particularly vulnerable to iodine deficiency. The popularity of organic products is growing, and attention should be paid to the iodine content of organic milk, as the iodine content of organic milk is usually lower than in conventionally produced milk. The aim of this study was to increase the iodine content of organic milk by adding two different species of seaweed, Ascophyllum nodosum and Laminaria digitata, to dairy cow diets, and thus create a sustainable mineral feeding strategy for dairy cows in organic production. The aim was to study the effect of dietary seaweed addition to iodine content of milk together with rapeseed cake or pea, as rapeseed cake is known to contain goitrogenic compounds that reduce iodine transfer to milk. The experiment was conducted at the Viikki Research Farm from 31 March to 25 June 2020. The experiment included 12 lactating Ayrshire cows and the experimental design was a cyclic changeover study. The factors studied were the effects of dietary protein source (rapeseed cake or pea) and the species A. nodosum or L. digitata on the intake of mineral and trace elements on dairy cows and on the mineral content of milk. In particular, effects on milk iodine were studied. The experiment had three 17-day trial periods and there was an 18-day wash-out period between the periods, when no seaweed was fed in order to minimize the carry-over effects between periods. The samples were collected on the last four days of the periods. Experiment included six dietary treatments in which protein feed was isonitrogenously either rapeseed cake or pea and diets were supplemented with seaweed. The dietary treatments were: rapeseed control K-R (no seaweed), pea control K-H (no seaweed), which were supplemented with 56,9 g dry matter (DM)/d A. nodosum i.e. seaweed 1 (M1- R, M1-H) and 7,8 g DM/d L. digitata i.e. seaweed 2 (M2-R, M2-H). The target iodine content of control diets was 1 mg/kg DM and seaweed diets 4 mg/kg DM. Finnish iodine recommendation for feeds that do not contain goitrogenic compounds is 1 mg/kg DM. Cows had ad libitum access to partial mixed ration that contained grass silage, barley and protein feed. In addition, concentrate was given to cows 1,8 kg/d and contained minerals (300 g/d), molassed sugar beet pulp, molasses and also seaweed in seaweed diets. The forage to concentrate ratio was 65:35. Mineral used in diets was approved for organic production and contained iodine 60 mg/kg DM. Dietary treatments did not affect DM intake. Compared to rapeseed diets, pea diets had a 0,15 kg/d lower crude protein intake, 0,24 kg/d lower crude fat intake and 49,7 µg/d lower iodine intake. Iodine intake increased on average by 63,4 µg when seaweed was added to the diet and the effect was greater when adding L. digitata compared to A. nodosum. Also, milk yield was lower with pea diets than with rapeseed diets. The iodine content of milk was higher with pea diets than with rapeseed diets (324 vs. 117 µg/l). Moreover, the addition of seaweed increased the iodine content of milk (on average +226 µg/l). Based on the results, iodine intake was lower with pea diets than with rapeseed diets, as expected, due to the higher iodine concentration of rapeseed cake. Both seaweeds increased the iodine content of milk, but the transfer of iodine to milk was higher with pea-based diets compared to rapeseed-based diets, due to goitrogenic compounds in the rapeseed cake.

Undernutrition and chronic micronutrient deficiency (hidden hunger) are serious problems around the world. Deficiencies in vitamin A, iron and iodine are the most common and they also cause the most health problems. In Mozambique there are micronutrient deficiencies in calcium, iron, iodine, selenium and zinc. Iodine deficiency decreases levels of thyroid hormones in the body. Thyroid hormones are in central role for example in fetal growth and child development. Furthermore, iodine deficiency causes different kinds of health problems in all age groups. Selenium deficiency can also affect levels of thyroid hormones. Selenium is needed in the activation of thyroid hormones. Also syanogenic glycosides from food can disturb thyroid metabolism. Cassava, which is commonly used food plant in Mozambique, is rich in these compounds. This master’s thesis focused on the iodine and selenium nutrition of teenage girls in Zambézia Province in Central Mozambique. I also studied how much these teenage girls use cassava as food. This master’s thesis is part of population-based cross-sectional ZANE-study. In ZANE-study diet and nutritional status of adolescent girls (15-18 years old) was studied in different types of communities in two seasons in 2010 in Quelimane, Maganja de Costa and Morrumbala. Iodine status of the girls was analysed by determining iodine concentration in urine spot samples (n=502). The selenium concentrations were determined from 522 serum samples. The thyroglobulin concentrations were also determined from the serum samples as another marker of iodine status. The results revealed that adolescent girls especially in Maganja de Costa and Morrumbala suffer from mild to moderate iodine deficiency. The median of urinary iodine concentration was 54,7 µg/l in Maganja de Costa (Q1 31,2; Q3 90,2) and 46,4 µg/l in Morrumbala (Q1 24,4; Q3 75,7). Urinary iodine concentration range 100-199 µg/l is an indicator of optimal iodine status. In Quelimane the median was 138,8 µg/l (Q1 86,8; Q3 199,4). Urinary iodine concentrations of pregnant girls were below the reference values in all areas. Serum thyroglobulin concentrations indicated also sub-optimal iodine intake. The serum selenium concentrations in the other hand were optimal in all areas. In Maganja de Costa, cassava was a staple food. In this study, iodine deficiency was observed in adolescent girls in Zambézia Province. Especially pregnant girls and their children are vulnerable group for iodine deficiency. Iodination of salt is an efficient way to increase iodine intake and iodination programmes should be made more efficient. In areas where cassava is commonly used, people should be advised to prepare it in a proper way. In this way possible disadvantages of cassava on iodine nutrition could be avoided.