Availability of Iron from Food Cooked in an Iron Utensil Determined by an In Vitro Method

Availability of iron from food cooked in iron utensils was determined by an in vitro method. Foods were cooked in iron (I) and in noniron (NI) utensils and combined to form meals. Applesauce and the meal contained more iron when cooked in I than in NI. The meals were subjected to simulated gastrointestinal digestion. Iron from the digestion mixture which diffused across a semipermeable membrane was measured calorimetrically and by radioassay. Treatment (cooked I vs NI) did not affect dialyzable iron. The radioassay showed higher dialyzable iron than the calorimetric method. Iron added to food by cooking in iron utensils was as available (as indicated by dialysis) as native food iron.     

A comparative study of the nutritional values,volatiles compounds,and sensory qualities of pea pastes cooked in iron pot and clay pot

In the current study, the nutritional values, volatiles compounds, and sensory qualities of pea pastes cooked in iron pot and clay pot were compared. Results showed that the iron pot‐cooked pea pastes contained profoundly more iron, total sugar, and starch than the clay pot‐cooked ones, and the effects were found related to iron ion by comparing the results between clay pot‐cooked pastes with and without iron ion addition. Samples prepared with the two utensils demonstrated similar contents of protein, polyphenol, and tannin, but differed in the composition of some volatile alcohols, alkanes, aldehydes, ketones, esters, and organic acids. The clay pot‐cooked samples had higher score of “color,” “mouthfeel,” “taste,” and “overall quality” than the iron pot‐cooked pastes. In conclusion, iron pot can allow the production of iron‐enriched pea pastes whose sensory qualities are remarkably lower than those of the clay pot‐cooked samples but are still in the acceptable range.

Practical applications

Iron utensil plays an important role in modern food industry due to its durability and convenience to handle. Cooking with iron pot is a simple and useful method of dietary iron fortification for the prevention of iron‐deficiency anemia in developing countries. Pea paste is a popular legume food with high nutritional value and good palatability. Traditional pea paste producers believe cooking with clay pots can give rise to product with more desirable features than using iron pots. However, there were no scientific evidences regarding the effects of cooking utensils on pea paste qualities. It has been proved in the current study that iron pot can allow the production of iron‐enriched pea pastes whose sensory qualities are remarkably lower than those of the clay pot‐cooked samples but are still in acceptable range.     

Iron, Zinc, Copper and Magnesium Binding by Cooked Pinto Bean (Phaseohs vulgaris) Neutral and Acid Detergent Fiber

Iron, copper and zinc but not magnesium were bound by neutral (NDF) and acid (ADF) detergent fiber obtained from cooked pinto beans. Iron binding increased with higher pH, higher iron concentration, higher fiber concentration and smaller fiber particle size. Maximum binding of iron was at pH 6.5 and minimal binding at pH 4.0 for both NDF and ADF. A 50% decrease in particle size increased iron binding by 8%. Binding of copper and zinc increased with higher copper and zinc concentrations. Both NDF and ADF had a greater affinity for copper than for either iron or zinc. Scatchard plots indicated the presence of two types of binding sites for zinc, one type for iron, and one type for copper.     

Heating Cruciferous Vegetables Increases in Vitro Dialyzability of Intrinsic and Extrinsic Iron

Iron dialyzability (ID) from three Cruciferae (broccoli, kale and cabbage) was determined by an in vitro digestion method. The effect of added Crucifers on the ID of extrinsic nonheme iron as well as effects of heating were studied. Uncooked Crucifers contained iron of moderate ID (7–9%); cooking resulted in substantial ID increase (200%). Cooked Crucifers increased extrinsic ID three- to fourfold. Time and temperature relationships for the increase suggested that organic acids released after partial cell wall degradation combined with protein denaturation and iron solubilization from fiber were major reasons for differences between raw and cooked vegetables. Cruciferous vegetables can contribute to improved iron nutrition.     

IRON CONTENT, SENSORY EVALUATION, AND CONSUMER ACCEPTANCE OF FOOD COOKED IN IRON UTENSILS

The purpose of this study was to determine the effect of cooking food in iron utensils on the iron content, sensory quality, and consumer acceptance/ preference of the food. Hamburger patties and applesauce were cooked in iron and in glass utensils and were analyzed for iron content by atomic absorption spectrophotometry and evaluated by a trained sensory panel, by consumers, and for chroma, pH, and refractometer changes. Cooking hamburger patties and applesauce in iron utensils increased iron in the food, did not affect sensory quality or consumer acceptance/preference of hamburger patties, but affected the color and flavor and decreased consumer acceptance/preference for applesauce.     

Iron Bioavailability from Common Raisin-containing Foods Assessed with an In Vitro Digestion/Caco-2 Cell Culture Model: Effects of Raisins

The effects of raisins on iron bioavailability from wheat bran cereal, bread, rice pudding, and granola bars were studied. Iron bioavailability was assessed with an in vitro digestion/Caco‐2 cell culture model. Raisins reduced iron bioavailability from all foods except granola bars. Raisins also reduced iron bioavailability from samples of wheat bran cereal and bread fortified with elemental iron or ferrous sulfate, but this inhibitory effect was less pronounced in samples fortified with sodium iron ethylenediaminetetraacetate (NaFeEDTA). Iron bioavailability was markedly higher for samples fortified with NaFeEDTA, suggesting that iron in the form of NaFeEDTA is more bioavailable than elemental iron or ferrous sulfate in raisin‐containing foods.     

Effect of Iron on the Color of Barley and Other Cereal Porridges

ABSTRACT: Iron added as ferrous sulfate at 500 mg*kg⁻¹ to rice, oats, whole grain wheat, or proanthocyanidin-free barley porridge caused significant changes in the Hunter "L", "a", and "b" values but the visual appearance of these porridges remained satisfactory. Porridge made with normal barley flour fortified with 500 mg*kg⁻¹ of iron developed an unappealing gray color with ferrous sulfate, ferrous fumarate, or electrolytic iron, 3 salts differing in solubility. At 100 and 250 mg*kg⁻¹ of iron, the discoloration of normal barley porridge was less pronounced, but still objectionable. When fortified with 50 mg*kg⁻¹ of iron, normal barley porridge had a slight color change but was not noticeably gray. Thus barley-containing foods can be fortified with a soluble iron compound at the level of iron used in enriched flour and similar cereal-grain foods for the general population without developing an unattractive color.     

Iron Binding by Fiber is Influenced by Competing Minerals

Iron was bound by neutral (NDF) and acid (ADF) detergent fibers extracted from cooked pinto beans (Phaseolus vulgaris). Soluble iron (total iron minus bound iron) in the presence of NDF was increased from 13.11 ± 5.08 to 35.58 ± 9.20% and from 22.22 ± 164 to 29.98 ± 0.96% when 1.17 and 1.38 ppm (18.4 and 21.4 PM) of copper and zinc were added, respectively. In contrast, 0.93 μm (14.6 PM) of copper decreased the soluble iron from 61.02 ± 5.77 to 17.88 ± 4.5% in the presence of ADF. Neither magnesium or cobalt altered the amount of soluble iron in the presence of fiber. The change in soluble iron was directly proportional to the concentration of copper and zinc. The presence of two types of binding sites is proposed.     

Dietary Iron in Swine Rations Affects Nonheme Iron and TBARS in Pork Skeletal Muscles

Fifteen crossbred pigs (mean wt = 25 kg) were allocated to three groups and fed to market weight (mean wt = 103 kg) on corn-soy based diets containing either 62,131, or 209 ppm iron. After slaughter, the longissimus dorsi (LD) and rectus femoris (RF) muscles were dissected, cooked, and stored in oxygen-permeable bags for 12 days at 4°C. Cooking increased thiobarbituric acid reactive substances (TBARS) but did not affect nonheme iron (NHI) or α-tocopherol. NHI and TBARS increased continuously during storage while α-tocopherol decreased. NHI and TBARS were higher in cooked pork from pigs fed high-iron diets. Liver iron correlated with muscle iron (p<0.05).     

Effect of Thermal Processing on Endogenous and Added Iron in Canned Spinach

The effect of thermal processing on endogenous and added iron in canned spinach puree was investigated. Eight different sources of iron were evaluated for their distribution of iron forms, or “iron profile” after four treatments. The treatments included: control, unprocessed, processed, and processed with ascorbate. Iron endogenous to raw spinach was 93% in the insoluble form whereas iron added to spinach varied widely in degree of insolubility. For certain iron sources, processing increased the proportion of insoluble as well as ferrous iron over what was present in unprocessed spinach. Processing with ascorbate also increased ferrous iron in some cases. One iron source, ferric EDTA, was exceptional as it was affected minimally in all four treatments. The effects of foods and processes on iron chemistry may help explain the large variations in iron absorption observed from various foods and diets.     

Iron Distribution in Heated Beef and Chicken Muscles

Distribution of iron in six fractions (water-soluble, water-insoluble, diffusate, hematin, total heme, and ferritin) of beef and chicken muscles hcatcd to 55, 70, 85, and 100°C was determined. Iron content decreased in water-soluble fractions and increased in water-insoluble fractions as temperature increased from 27°C to 100°C. Heme iron decreased more from 55°C to 85°C than from 27°C to 55°C or 85°C to 100°C. The increase in diffusate iron appeared to be less than the decrease in heme iron at each heating temperature. As temperature increased from 27°C to 100°C, hematin iron content increased and extractable ferritin iron content decreased. These findings may help explain rapid development of oxidative rancidity in cooked meat.     

Dietary Iron and Colorectal Cancer Risk: A Review of Human Population Studies

Iron is an essential micronutrient that is involved in many redox processes and serves as an integral component in various physiological functions. However, excess iron can cause tissue damage through its pro-oxidative effects, potentiating the development of many diseases such as cancer through the generation of reactive oxidative species. The two major forms of iron in the diet are heme and nonheme iron, both of which are found in several different foods. In addition to natural food sources, intake of nonheme iron may also come from fortified foods or in supplement form. This review summarizes the results of human population studies that have examined the role of dietary iron (heme and nonheme), heme iron alone, and iron from supplements in colorectal carcinogenesis.     

Leaching of aluminium from utensils during cooking of food

The use of aluminium utensils for cooking provides an important route for aluminium metal to enter foods. Leaching of aluminium from utensils made of aluminium, indalium (alloy of aluminium), stainless steel and hard anodised aluminium was studied under different conditions of pH and boiling time. Low pH was found to enhance leaching of aluminium from the utensils. The leaching was found to be the highest during first‐time preparation (new utensils) of all the foods as compared with second‐and third‐time preparations using the same utensils. Leaching of aluminium during the preparation of various traditional Indian foods was found to be negligible in hard anodised aluminium utensils, indicating the advantage of using such vessels for food preparation over simple aluminium and indalium utensils. Cereals contribute a smaller amount of aluminium to the total daily intake than legumes. Copyright © 2006 Society of Chemical Industry     

In vitro Extractability of Calcium, Iron, and Zinc in Finger Millet and Kidney Beans During Processing

ABSTRACT: Finger millet ( Eleusine coracana ) and kidney beans ( Phaseolus vulgaris ) were processed by soaking, germination, autoclaving, and fermentation for incorporation into a complementary food for children. Extract-ability of calcium, iron, and zinc were determined by in vitro HCl-Pepsin and Pepsin-Pancreatin methods after each processing step. Germination significantly increased the in vitro extractability of these minerals, while soaking, autoclaving and fermentation showed a smaller or insignificant effect. Iron extractability was low in germinated, autoclaved and fermented millet, as determined by the pepsin-pancreatin method, but increased 6.8 times with addition of vitamin C. Phytic acid was reduced by 85 and 66% in finger millet and kidney beans, respectively, during the overall processing. These results show that various processing methods, especially germination, increase mineral extractability. Addition of vitamin C and mango could be used to enhance mineral extractabilities, thereby helping to alleviate micronutrient deficiencies in populations subsisting on these foods.     

Iron content and availability studies in some Sri Lankan rice varieties

Thirty‐eight rice varieties, grown in Low Country Wet Zone, during Yala (2006) and Maha (2006/2007) seasons were screened for stable high iron rice varieties and were statistically analysed. Iron contents ranged 1.89–3.73 mg 100 g^?1 and varied significantly (P < 0.05) with variety and season. Selected fifteen high iron rice varieties, at degree of polishing 8–10% were analysed for iron, zinc and phytate. High iron contents in endosperm were observed in Suduru Samba (0.47 mg 100 g^?1), Basmati 370 (0.37 mg 100 g^?1), Kalu Heenati (0.42 mg 100 g^?1), Rathu Heenati (0.44 mg 100 g^?1) and Sudu Heenati (0.37 mg 100 g^?1). Phytate contents of polished rice varieties ranged from 200–300 mg 100 g^?1. Large reduction in iron content (84.5–93.6%) was observed in polished rice while the reduction in phytate content (18.9–40.8%) was low. Percentage dialyzability of iron in selected endosperm high iron rice varieties ranged from 1.73 to 8.71. Dialysability of iron in cooked polished rice did not show a relation to the phytate content in raw rice.     

The dietary significance of adventitious iron, zinc, copper and lead in domestically prepared food

The uptake of iron, zinc, copper and lead by food cooked under domestic conditions in utensils made of different metals (cast iron, aluminium, plain and tinned copper) was investigated. It was found that the metal content of the food was generally related to the metal in immediate contact with the food during cooking. Daily dietary intake could vary from 11 to 6 mg of iron, 11 to 9 mg of zinc, 2 to 1 mg of copper and 0.4 to 0.1 mg of lead, depending on the cooking utensils used. Dietary intake of the metals was also related to sources and domestic practices regarding water supply. Consistent use of municipal water from a domestic hot water system could contribute a daily intake of 32 mg iron, 29 mg zinc and 12 mg copper. Rainwater stored in a galvanized iron tank could provide 23 mg of zinc per day when used for domestic purposes. The nutritional and toxicological significance of such adventitious sources of metals in the diet are discussed. The need to consider them when investigating the metal intake of individuals is stressed.     

Cooking rice in excess water reduces both arsenic and enriched vitamins in the cooked grain

This paper reports the effects of rinsing rice and cooking it in variable amounts of water on total arsenic, inorganic arsenic, iron, cadmium, manganese, folate, thiamin and niacin in the cooked grain. We prepared multiple rice varietals both rinsed and unrinsed and with varying amounts of cooking water. Rinsing rice before cooking has a minimal effect on the arsenic (As) content of the cooked grain, but washes enriched iron, folate, thiamin and niacin from polished and parboiled rice. Cooking rice in excess water efficiently reduces the amount of As in the cooked grain. Excess water cooking reduces average inorganic As by 40% from long grain polished, 60% from parboiled and 50% from brown rice. Iron, folate, niacin and thiamin are reduced by 50–70% for enriched polished and parboiled rice, but significantly less so for brown rice, which is not enriched.     

Three Methods for Determining Nonheme Iron in Turkey Meat

The ferrozine, the Schricker and modified Schricker methods were used to measure the non-heme iron in raw and cooked turkey meat. The ferrozine method gave the lowest non-heme iron values, while results from the Schricker and modified Schricker were not different (p<0.05). When hemoglobin (Hb) was added to breast meat, how-ever, differences (p<0.05) between the Schricker and modified Schricker, and Schricker and ferrozine methods were observed in cooked meat with NaCl. Cooking and addition of NaCl caused increase in measured nonheme iron content and had a synergistic effect on the release of nonheme iron in meat.     

Effect of Form of Enrichment and Iron on Thiamin, Riboflavin and Niacinamide, and Cooking Parameters of Enriched Spaghetti

The effect of encapsulation, iron and low (LT) or high (HT) temperature drying on thiamin, riboflavin and niacinamide concentrations and on cooked spaghetti parameters of enriched spaghetti were studied. Thiamin, riboflavin and niacinamide were greater in the encapsulated enriched spaghetti. Cooked spaghetti had lower cooked weight but greater firmness when enriched with encapsulated vitamins. Thiamin, niacinamide and cooked weight were greater in cooked spaghetti when iron was added, but spaghetti was less firm. High temperature drying resulted in lower riboflavin and niacinamide in dried spaghetti but did not affect vitamin concentrations in cooked spaghetti. High temperature drying caused less cooking loss and greater firmness in cooked spaghetti.     

Effect of Calcium Level on Bread Iron Utilization by Iron-Deficient Rats

Utilization of iron in bread containing variable amounts of calcium was examined using iron-deficient rats as the test model. Iron was added to the bread at the normal enrichment level. Calcium, however, was added at levels up to 9 times the normal level. Iron utilization efficiency (IUE) was calculated based on collective increases observed in hemoglobin and liver iron. Compared to a diet low in both calcium and phosphorus (IUE = 100%), IUE averaged 98% when the diet was high in calcium but moderate in phosphorous, and 78% when the diet was very high both in calcium and phosphorous. Viewed collectively, the data suggested that excessive intake of both calcium and phosphorus would adversely affect the utilization of iron in bread, but some excess of calcium alone would not.