Iron bioavailability from Amaranthus species: 1—In vitro dialysable iron for estimation of genetic variation

Green leafy vegetables have the potential to contribute significant amounts of iron to the diet, if the bioavailability of iron from these foods is improved. In order to determine the potential for genetic manipulation of this trait, 46 lines from 12 species of Amaranthus were evaluated for total and bioavailable iron in greenhouse and field experiments. Bioavailable iron was estimated using an in vitro assay for dialysable, low-molecular-weight iron compounds. Significant differences (P < 0·01) were detected among lines and species for total and bioavailable iron. Total iron ranged from 358 to 880 ppm (dry weight) in field-grown plants and 55 to 123 ppm (dry weight) in greenhouse-grown plants. Bioavailable iron ranged from 41 to 63 ppm in field-grown plants and from 24 to 51 ppm in greenhouse-grown plants. Amaranthus tricolor and A lividus had the highest total and bioavailable iron; A hypochondriacus had the lowest levels of the species tested. Although field-grown Amaranthus accumulated higher levels of total and bioavailable iron, a greater proportion of the total iron was sequestered in insoluble, unavailable forms. Generally, species with higher total iron had higher levels of bioavailable iron. These analyses indicated potential for genetic improvement of iron nutritional quality from Amaranthus, especially within the species A tricolor. © 1998 Society of Chemical Industry     

Amaranth seed varieties. A chemometric approach

In this work, the amino acid and fatty acid profiles were determined in two advanced lines of amaranth seeds: Amaranthus hypochondriacus × Amaranthus cruentus AH17a and Amaranthus cruentus AcG6/17a; as well as in two new varieties: Amaranthus cruentus var. Candil and Amaranthus hypochondriacus var. Dorado. The following contents were found: protein (18.76–26.00 %), dietary fiber (15.91–17.80 %) and total lipids (10.62–11.44 %), high concentrations of unsaturated fatty acids (77.80–82 % of total lipids), linoleic acid (41.94–55.50 % of total lipids) and lysine (47.3–68.6 mg g^?1 of protein) were also found. Based on these composition data, chemometric tools were used to classify these new varieties and lines by unsupervised methods—principal component analysis and cluster analysis; as well as by supervised methods—sequential discriminant analysis (DA) and partial least squares DA. It was possible to correctly classify all varieties and lines using 11 variables. In conclusion, it was found that new varieties and advanced lines of amaranth show proper nutritional quality, which reveals the potential of this genus as agro-food. Also, a complete chemometric assessment allowed us to distinguish between these new varieties and lines.     

A Simple Laboratory Scale Method for Isolation of Amaranth Starch

Starch was isolated from the seeds of Amaranthus hypochondriacus and Amaranthus cruentus by two established methods and a new simpler method involving steeping in dilute alkali, neutralization, and ambient air drying without using expensive or highly hazardous chemicals. The latter is recommended for isolating amaranth starch for human food uses on a laboratory scale.     

Nutritional study of raw and popped seed proteins of Amaranthus caudatus L and Amaranthuscruentus L

The nutritional value of raw and popped (similar to popcorn preparation) seed proteins of two amaranth species, Amaranthus caudatus L and A cruentus L, was investigated. After popping, the true protein content in A caudatus and A cruentus decreased by 9 and 13% respectively. Among the amino acids, the loss of tyrosine due to the popping effect was the highest, followed by phenylalanine and methionine. Leucine was the first limiting amino acid in the raw samples, followed by lysine, while the reverse order was observed in the popped samples. The in vivo protein quality of raw and popped seeds was tested with male weanling rats and compared with wheat flour and casein samples. There was no difference between the in vivo digestibility of the raw and the popped seeds, although the in vitro digestibility was slightly higher for the popped samples. The protein efficiency ratio (PER) for all the amaranth seed samples was higher than that for the wheat sample, while the PER for the raw amaranth seed samples was close to that for the casein reference protein. The rat blood serum levels of total cholesterol, triglycerides and high‐density lipoprotein cholesterol for all the amaranth samples were lower than those for the reference protein, while the wheat flour sample showed the lowest values. Copyright © 2004 Society of Chemical Industry     

Effect of Squid Ink Melanin‐Fe on Iron Deficiency Anemia Remission

ABSTRACT: The present study was designed to evaluate the effect of a new iron tonic (squid ink melanin‐Fe [SM‐Fe]) on remission of iron deficiency anemia (IDA) using a rat model of IDA. The rat IDA model was established with low‐iron diet feeding and caudal vein blooding. Then different dosages of SM‐Fe were given to the rats once a day by intragastric administration, with FeSO₄ and FeCl₃ as positive control. The content of Hemoglobin (Hb), red blood cell (RBC), hematocrit (HCT), and mean corpuscular volume (MCV) were analyzed in addition to the contents of serum iron (SI) and intracellular free erythrocyte protoporphyrin (FEP). The content of malondialdehyde (MDA) and the activity of superoxide dismutase (SOD) and glutathione peroxidase (GSH‐Px) in serum was also measured. The results showed that anemia caused by iron deficiency was established as a consequence of the low‐iron diets. SM‐Fe showed an effective restoration action by returning Hb, RBC, HCT, MCV, SI, and FEP in IDA animals to normal values. An antioxidant effect was also observed that reduced MDA level, enhanced the activities of SOD and GSH–Px in serum, and protected erythrocytes from the injury of reactive oxygen species as a consequence of SM‐Fe intake. In comparison with FeSO₄ and FeCl₃, higher bioavailability of iron and fewer side effects were also observed. In conclusion, SM‐Fe remitted iron deficiency anemia symptoms significantly, suggesting that SM‐Fe might contribute to improving hemopoietic function in IDA rats and might be exploited as a safe, efficient new iron tonic.     

The Starch of Amaranthus — Physico-chemical Properties and Functional Characteristics

Starch from four varieties of amaranth grain were examined by scanning electron microscopy. Physico-chemical properties, including swelling power, solubility, water binding capacity, enzyme susceptibility, amylograph viscosity, and amylose, were determined. Functional characteristics, including bread and cake baking performance were studied. The granules of starch isolated from seeds of Amaranthus cruentus and Amaranthus hypochondriacus were found to be very small in size. They were angular and polygonal in shape. Compared to corn starch, the amaranth starches had a higher swelling power, a lower solubility, a greater water binding capacity, a lower susceptibility to α-amylase, a higher amylograph viscosity and much lower amylose content. The amaranth starches produced very poor quality breads and cakes. The breads and cakes were low in volume, lacked symmetry, and had inferior grain, texture and crumb color.     

Effect of the consumption of amaranth seeds and their sprouts on alterations of lipids and glucose metabolism in mice

Amaranth (Amaranthus hypochondriacus) is appreciated for its nutritional and functional quality. This study evaluated the effects of consuming amaranth seeds and their sprouts on the metabolic markers in ICR male mice. Ungerminated amaranth seeds (A) and one-day (G1) and three-day (G3) germinated amaranth sprouts were dried and milled. The mice groups (n = 10) were fed standard (N) or hypercaloric (H) diets and 1 g A, G1 or G3/kg body weight for 28 days. The total cholesterol (TC), high- and low-density lipoprotein (HDL and LDL), atherogenic index (AI), triglyceride (TG) and glucose levels were determined in blood samples. Germination increased the dietary fibre, phenolic and flavonoid concentration and decreased ash and squalene concentration. A, G1 or G3 consumption also decreased body weight, TC, LDL, AI and glucose levels in H group mice. Thus, amaranth seed or sprout consumption could be beneficial for people with altered lipid metabolism.     

Rheological properties of starches from grain amaranth and their relationship to starch structure

Amaranth starch (Amaranthus cruentus L. and Amaranthus hypochondriacus L.) in this investigation possessed a relatively small and uniform granule size of a type “A” pattern obtained by X‐ray diffraction, with the degree of crystallinity ranging from 24.5 to 27.9%. This was followed by work on steady and dynamic rheological properties on shear of seven native amaranth starches. Aqueous pastes (5% solids) exhibited shear‐thinning behavior, and the flow behavior was fitted with the Herschel–Bulkley equation (regression coefficients were over 0.99). Cultivar V69 showed much higher G′ (storage modulus) and G″ (loss modulus) than the other samples and produced a solid‐like gel, which could be attributed to the high amylose content of its network. Correlation analysis revealed that amylose content was positively correlated with G′ and negatively with the loss tangent (tan δ) of the material.     

Iron bioavailability from ferric pyrophosphate in rats fed with fructan-containing yacon (Smallanthus sonchifolius) flour

The effects of inulin-type fructans (ITF)-containing yacon flour (YF) on Fe bioavailability from ferric pyrophosphate (FP) were evaluated in Fe-deficient rats using the Hb repletion efficiency (HRE) assay. Weanling male Wistar rats were fed a low-Fe diet (12 mg/kg) for 15 days followed by 2 weeks of Fe repletion with diets providing 35 mg Fe/kg as either ferrous sulphate (FS) or FP, supplemented with 7.5% ITF as either YF or Raftilose (RAF), a purified ITF. ITF increased caecal fermentation, whereas YF was more butyrogenic than RAF. ITF improved HRE in FP-fed rats, and those fed YF had a higher relative biological value compared with those fed FP and RAF. Liver Fe was increased by ITF, but only YF led to values similar to those in the FS group. It is observed that ITF increased caecal fermentation and Fe bioavailability. These effects were more pronounced when YF was the ITF source.     

Characterization of Amaranthus cruentus and Chenopodium quinoa Starch

Starches from amaranth (Amaranthus cruentus) and quinoa (Chenopodium quinoa) were isolated and investigated by using enzymatic assay, Rapid Visco Analysis (RVA), Differential Scanning Calorimetry (DSC), Scanning Electron Microscopy (SEM) and X-ray Diffractometry (XRD). Amylose content measured enzymatically was 7.8 and 11.2 % for amaranth and quinoa starch, respectively. Quinoa starch was much more viscous than amaranth starch and gelatinized at a lower temperature as determined with RVA. DSC demonstrated a wider gelatinization temperature range for amaranth starch (20.6°C) than for quinoa starch (11.1°C). SEM observation revealed polygonal shape of starch granules, and XRD suggested a typical Atype diffraction pattern for both the starches in question. A crystallinity of 45.5 % for amaranth and 35.4 % for quinoa starch, respectively, was also determined from the XRD collected data.     

Iron absorption and haemoglobin status of rats fed a ferrous bisglycinate‐fortified growing‐up milk

BACKGROUND: Infants and toddlers aged 6–24 months constitute one of the groups at highest risk of iron deficiency. A promising alternative for ferrous sulfate (FS) might be ferrous bisglycinate (FeAAC), which is less likely to cause sensory changes in the food vehicle. This work aims to compare the effect of FeAAC with that of FS, when added to a growing‐up milk, on the iron and haemoglobin status in weanling rats using a depletion–repletion model. RESULTS: After the repletion period no significant differences were found in iron absorption, Hb concentration, Hb iron, Hb regeneration efficiency (HRE), mean corpuscular volume (MCV), mean corpuscular Hb (MCH), mean corpuscular Hb concentration (MCHC), serum iron, total iron binding capacity (TIBC), transferrin saturation (TS), and ferritin between the group fed a growing‐up milk fortified with FS and the group fed one fortified with FeAAC. Furthermore, iron absorption, HRE, MCV, MCH, serum iron, and TS were significantly (P < 0.05) higher in groups fed either type of iron‐fortified growing‐up milk compared to the control group (AIN‐93G diet). CONCLUSION: A growing‐up milk supplemented with FeAAC showed an improvement in the iron absorption and haemoglobin status at the same level as those of FS. Copyright © 2009 Society of Chemical Industry     

Application of phytases from bifidobacteria in the development of cereal-based products with amaranth

The effects of the inclusion of purified phytases from Bifidobacterium longum spp. infantis ATCC15697 and Bifidobacterium pseudocatenulatum ATCC27919 on phytate (InsP ₆) levels were analyzed during breadmaking process. Two different levels of whole amaranth (Amaranthus cruentus) flour (25 and 50 %) were used in bread dough preparation, and they were compared to control doughs made with 100 % wheat flour and 100 % whole wheat flour. Bread samples made with 50 % of amaranth flour showed a significant decrease in technological quality parameters in comparison with control white breads. However, a 25 % of amaranth flour improved the nutritional value of the bread, with only a slight depreciation in the quality. Addition of bifidobacterial phytases resulted in higher InsP ₆ degradation compared with a commercial fungal phytase, without affecting the bread quality. InsP ₆ reduction was especially efficient in breads with 25 % amaranth, leading to InsP ₆ levels below the threshold of mineral bioavailability inhibition for Fe and Zn in human nutrition.     

Effect of Heat Treatment on Meat Enhancement of Dietary Iron Bioavailability of Meat/Ferrous Sulfate and Meat/Hemoglobin Mixtures Fed to Anemic Rats

The effect of autoclaving on meat enhancement of dietary iron bioavailability was studied. Meat was mixed with FeSO₄ or hemoglobin to obtain ratios of iron from meat to iron from FeSO₄ or hemoglobin of 100:0, 75:25, 50:50, 25:75, and 0:100. One-half of each mixture (except meat:FeSO₄ mixture 0:100) was autoclaved for 90 min at 15 psi. The meat mixtures were lyophilized and formulated into diets to provide approximately 35 mg Fe/kg. Hemoglobin regeneration efficiency (HRE) was determined as the percent iron gained as hemoglobin relative to the iron consumed. Heat increased the HREs of meat/hemoglobin mixtures and of hemoglobin. Heat did not affect the HRE of meat or meat/ferrous sulfate mixtures. Meat did not significantly enhance the bioavailability of total dietary iron.     

Bioavailability of Zinc and Iron from Mature Winged Bean Seed Flour

The relative bioavailability of zinc and iron from mature winged bean (Psophocarpus tetragonolobus) flour was determined utilizing standard rat bioassay procedures. Weight gain of rats after 21 days and total bone (tibia) zinc resulting from zinc addition to the standard diet as zinc carbonate or from zinc endogenous to winged bean flour were compared. The relative bioavailability of winged bean zinc was calculated to be 85% (P < 0.05) and 93% (N.S.) when weight gain and log tibia zinc were the criteria of evaluation. The results of the hemoglobin repletion assay indicated that iron from winged bean was 89% (N.S.) as bioavailable iron from ferrous sulfate.     

Effect of tea phenolics on iron uptake from different fortificants by Caco-2 cells

The in vitro effects of tea phenolics on Fe uptake from different fortificants (FeSO₄, FeCl₃, FeEDTA) by Caco-2 cells were compared. Cell cultures were exposed to catechin, tannic acid, green or black tea solutions, added within Fe-containing solution, or used to pre-treat cell cultures before Fe-exposure. Cell ferritin formation was used as a measure of Fe uptake. Reverse phase chromatography was used to identify specific phenolics in tea solutions, and the Fe-binding catechol and galloyl groups were determined spectrophotometrically. The results showed a positive effect of catechin on Fe uptake only from dissociable Fe sources, and a marked inhibitory effect of tannic acid regardless of the Fe source. Tea phenolics exhibit similar inhibitory patterns on Fe uptake from FeCl₃ and FeEDTA solutions; however, the Fe uptake from FeSO₄ solutions was significantly less affected. These data improve the understanding of interactions by which tea phenolics affect Fe uptake at the intestinal level.     

Bioavailability to rats of iron from fortified grain amaranth flour

In this study, fortified and unfortified grain amaranth seed flour and FeSO₄ fortified casein diet as control were evaluated for their iron bioavailability. NaFeEDTA, ferrous fumarate, and FeSO₄-fortified grain amaranth were fed to Sprague Dawley weanling male rats. Iron intake, Hb Fe gain, Fe availability and binding capacity, serum iron, non-haem liver iron and relative biological value (RBV) were determined and values compared with FeSO₄-fortified casein control; all were improved greatly by fortification.
Relative biological values (RBV) were 0.40, 1.55, 1.75, 1.67 and 1.00 for animals receiving unfortified amaranth diet, those fed diet fortified with NaFeEDTA, ferrous fumarate, FeSO₄ and casein fortified with FeSO₄ respectively. RBV of the unfortified cereal was 40% of control suggesting perhaps low iron absorption from the amaranth cereal.
Based on the results of this study, amaranth cereal is ideal as a food vehicle for iron fortification. The iron fortificant of choice is ferrous fumarate.     

Starch properties of Amaranthus pumilus (seabeach amaranth): a threatened plant species with potential benefits for the breeding/amelioration of present Amaranthus cultivars

This study reports on the physicochemical properties of starch isolated from the seeds of Amaranthus pumilus (a threatened plant species) and compares it to that of the commonly cultivated/commercially produced Amaranthus hypochondriacus K343 (Plainsman). Seeds of both investigated species were found to possess comparable quantities/levels of total starch. Although no significant differences (P⩾0.05) were found between the composition of the two starches with regard to their moisture, ash, protein and fat contents, the starch of A. pumilus was found to contain significantly higher (P⩾0.05) amounts of amylose than that of A. hypochondriacus. The higher levels of amylose found in A. pumilus starch were believed to be responsible for the higher differential scanning calorimetric To, Tp and Te starch temperatures than those of A. hypochondriacus starch which would indicate higher levels of ordered crystalline structure in the former. Scanning electron microscopy and integrated light scattering techniques both revealed a uniform average starch granule diameter of approximately 1 μm for both investigated species. This study further supports and compliments a previous study which showed that much genetic diversity exists between A. pumilus and A. hypochondriacus, indicating that potential breeding possibilities for the improvement of commonly cultivated amaranth lines do exist, if A. pumilus is not first driven to extinction.     

Goat milk during iron repletion improves bone turnover impaired by severe iron deficiency

The effect of goat or cow milk-based diets, with either normal Fe content or an Fe overload, on bone turnover and the mineralization process was studied in control and anemic rats during chronic Fe repletion. One hundred eighty male Wistar rats were studied during a pre-experimental period of 40 d in which they were randomly divided into 2 groups, a control group receiving the AIN-93G diet with normal Fe content (45 mg/kg of diet) and the Fe-deficient group receiving the AIN-93G diet with low Fe content (5 mg/kg of diet) for 40 d. After the pre-experimental period, the rats were fed for 10, 30, or 50 d with goat or cow milk-based diets with a normal Fe content (45 mg/kg of diet) or an Fe overload (450 mg/kg of diet). In anemic rats, goat milk with normal Fe content increased levels of the biomarker of bone formation N-terminal propeptides of type I procollagen and diminished parathyroid hormone levels after only 10 d of supplying this diet, indicating the beginning of restoration of the bone demineralization induced by the anemia, which was not observed with cow milk. After 30 d of supplying the milk-based diets with normal Fe content or an Fe overload, biomarkers of bone formation and bone resorption were not different between control and anemic rats, indicating that the bone demineralization induced by the Fe-deficiency anemia had recovered, although the process of stabilization of bone turnover began earlier in the animals fed goat milk. In addition, a higher Ca deposit was observed in femur, which positively affects bone mineralization, as well as an increase of Fe in sternum, which indicates that the hematopoietic process essentially recovered earlier on the goat milk diet compared with the cow milk diet.     

Influence of Germination on Physico-chemical Properties of Amaranth Flour and Starch Microscopic Structure

A basic procedure was developed to germinate amaranth seeds (Amaranthus hypochondriacus). The “true” protein/total crude protein ratio decreased slightly after 36 h of germination. However, some of its rheological properties (e. g., farinographic and viscographic performances) were substantially improved by such simple treatment. Ultrastructural changes of the starch, as assessed by scanning electron microscopy, were also followed during this process. The smooth surface and dense packing of the starch in untreated seeds were outstandingly modified during germination. This procedure might contribute to widen the restricted food uses of this nutritious crop.     

Analysis of element species fractions in buckwheat and amaranth flours by SEC/ICP-MS and MALDI-MS

Fractionation of Co, Cu, Fe, Mn, Mo, Ni, P and Zn in extracts of buckwheat and amaranth flour in 0.02 mol·l⁻¹ Tris-HCl (pH = 7.5) buffer was performed by SEC/ICP-MS. All metals except for Fe and Mn (both samples) and Cu (amaranth only) are concentrated in a low-molecular fraction (M _r < 2 kDa). Fe is bound in a high-molecular fraction (M _r > 150 kDa). The main part of Mn is present as a labile complex or an ionic form. Cu in amaranth extract is also bound in medium-molecular fractions (10 and 40 kDa) and in a high-molecular one (M _r > 150 kDa). Fractions rich in trace metals were isolated using preparative-scale SEC and the organic ligands of metals were refined by immobilized metal affinity chromatography. Low content of sulphur-containing amino acids (Cys, Met) and high content of acidic amino acids (Glu, Asp) are typical for all these purified fractions. A part of Zn (buckwheat) and almost all Cu (amaranth) in the low-molecular fractions were located in phosphorus rich sub-fractions. However, all Ni (both samples), the majority of Zn (buckwheat) and all Cu (buckwheat) were found in phosphorus-less sub-fractions. No phytochelatins were found in MALDI-MS spectra of isolated ligands.