Evaluation of iron‐fortified Feta cheese for physicochemical and sensory properties

Standardised cow's milk (fat 3 g/100 g) was used to manufacture Feta cheese fortified with 40, 60 and 80 mg of iron/kg cheese using ferrous sulphate (FeSO₄), ferric chloride (FeCl₃), ferric pyrophosphate (Fe₄ (P₂O₇)₃) and microencapsulated ferrous sulphate. Chemical composition and sensory characteristics of fortified cheeses were determined after 60 days of ripening, during which the iron content and thiobarbituric acid (TBA) values were measured. The metallic taste, colour, flavour, overall score and TBA values were statistically (P < 0.05) affected by the source and concentration of iron. The best quality was found in cheeses fortified with 40 mg/kg of microencapsulated ferrous sulphate.     

Key properties of iodine‐, iron‐ and zinc‐ fortified fish cracker: effects of ambient shelf storage on iodine retention and quality indicators

Multi‐micronutrient (MN)‐fortified fish cracker could be used as a means to improve iodine, iron (Fe) and zinc (Zn) status. We evaluated iodine stability as well as the quality and sensory properties of MN‐fortified fish cracker, at the fortification levels of 5.3 mg per 100 g for Fe and Zn and 260 μg per 100 g for iodine in the dough. On average, the overall retention of iodine after processing and storage for 4 months was ~65%. Fortification with KIO₃ + ZnO, or KIO₃ + ZnO + ferrous fumarate, significantly increased the loss of iodine during processing. The Fe compounds tended to promote iodine instability during storage and contributed to thiobarbituric reactive substances. Fortification did not affect linear expansion of the cracker. Triple‐fortified fish cracker with KIO₃, ferric pyrophosphate and ZnO exhibited both high iodine retention (92.7% for steaming + drying and 72.7% for storage) in the tropical conditions (30 ± 1 °C, 80 ± 5% R.H.) and achieved overall desirable sensory scores. Thus, such fortification of fish cracker might successfully supplement iodine, zinc and iron, while at the same time contributing to the palatability of cracker.     

Optimisation of in vitro measurement of available iron from different fortificants in citric fruit juices

The percentage of dialyzable ferrous and total iron were studied in a citric juice (pineapple and passion fruit) fortified with ferrous sulphate, micronised dispersible ferric pyrophosphate and ferrous bis-glycinate in similar concentrations (49.2 mg Fe/l). The in vitro method of Kapsokefalou and Miller (1991) [Kapsokefalou, M., & Miller, D. D. (1991). Effects of meat and selected food components on the valence of nonheme iron during in vitro digestion. Journal of Food Science, 56, 352–355.] was optimised for this matrix using 0.15 N PIPES buffer (pH 8.5) to adjust pH during pancreatic digestion. We also studied different pH values of Hepes buffer used in the measurement of iron concentrations with Ferrozine (chromogen solution). The maximum absorbances were obtained with a Hepes buffer pH value of 8.5. Ferrous sulphate was used as a reference salt due to its high bioavailability, although novel compounds, such as ferrous bis-glycinate and micronised dispersible ferric pyrophosphate, showed a high relative iron availability in this juice. Taking into account that percentage of dialysable ferrous iron is considered to be the more available fraction of total iron, the iron fortificant ferrous bis-glycinate proved to be more adequate for fortifing citric juices, giving a 10.7% of dialyzable ferrous iron. Moreover, the percentage of dialyzable total iron from ferrous bis-glycinate (31.0%) was statistically higher than those from ferrous sulphate and micronised ferric pyrophosphate (28.4% and 28.2%, respectively).     

The influence of vegetable puree containing carotenoids on the nutrient composition and structure of milk yoghurt

The aim of this study was to develop technology to produce a mashed pumpkin yoghurt rich in β‐carotene and to check its physicochemical properties and nutritional values. The structural and mechanical properties of the yoghurt product, as well its basic nutrient content and antioxidant activity, were studied. Yoghurt fortified with pumpkin puree has the potential to normalise the commensal intestinal microbiota and has potential as a dietary health supplement. The experimental yoghurt samples that were produced had physicochemical properties comparable to commercially produced yoghurt: the pumpkin‐supplemented samples contained 4.5% fibre, 8.5 mg/100 g vitamin C and 8.9 mg/100 g β‐carotene.     

STORAGE STABILITY OF FERROUS IRON IN WHOLE WHEAT FLOUR NAAN PRODUCTION

Premix containing ferrous sulfate, ethylenediamine tetraacetic acid and folic acid (20.0:20.0:1.5 ppm) was used to fortify whole wheat flour stored at ambient temperature for 42 days. Naans (flat bread) were prepared from 0‐, 20‐, 40‐ and 60‐ppm ferrous iron‐fortified flour samples at weekly intervals and were analyzed for physicochemical constants and sensory evaluation. It was observed that flour containing 60‐ppm ferrous sulfate contained the highest iron residues. Total iron in flour samples showed no significant difference, while ferrous iron significantly decreased in fortified flour (0.53–3.08%) and in the naans (0.42–3.48%) because of its oxidation to ferric iron during storage. Phytic acid content decreased (0.886–0.810%) significantly during the same storage period. Iron levels affected some sensory characteristics significantly (P ≤ 0.05) including color, texture, flexibility, chewability and overall acceptability of the naans, but not taste and flavor. The sensory attributes of naans illustrated that naans containing 40‐ppm ferrous iron are more acceptable than those prepared with 60‐ppm ferrous iron.     

Stevia‐fortified yoghurt: Stability,antioxidant activity and in vitro digestion behaviour

In this study, yoghurt samples were fortified with 0.25% and 0.5% freeze‐dried stevia extract (FSE). The control and stevia‐fortified yoghurts were evaluated and compared for the viability of the starter cultures, physicochemical properties, total phenolic content (TPC) and antioxidant activity throughout 30 days of storage. In addition, TPC and antioxidant activity were evaluated during in vitro gastrointestinal digestion. The results showed that the yoghurt matrix preserved the TPC, antioxidant capacity and total solids during storage, while the acidity, synaeresis and counts of the starter cultures of the final product were not significantly affected. However, addition of 0.5% FSE exerted a buffering effect on the system. After simulated digestion, the values of TPC and antioxidant activity of the fortified yoghurts increased in relation to the undigested fractions. These findings showed the feasibility of employing FSE as a functional ingredient in the manufacture of yoghurts with potential antioxidant properties.     

Casein micelles as a vehicle for iron fortification of foods

Casein micelles were loaded with iron to create a dispersible delivery format for insoluble iron by exposing milk at chilled temperatures to a high concentration of soluble iron (up to 20 mmol kg⁻¹ ferrous and ferric chloride). The loading was maximised by applying a pH-cycle to the fortified milk by means of carbonation. Upon acidification of fortified milk, no release of iron was observed, except at the highest concentration. Changes in the buffering capacity as a function of pH confirmed the formation of colloidal iron phosphates. Overall, most properties of the micelles did not change: hydration, protein distribution between soluble and colloidal phase remained constant, but zeta potential decreased slightly and curd formation upon renneting became much slower. The renneting behaviour could be improved by carbonation or storage at 30 °C for a day. Iron-fortified milk samples were stable under heating, except when fortification was achieved by means of 20 mmol kg⁻¹ ferric chloride. The most obvious difference of iron-fortified milk is its appearance: samples fortified with ferrous chloride were darker than control, whereas samples fortified with ferric chloride were more red/yellow.     

Sensory characteristics and iron dialyzability of gluten-free bread fortified with iron

The objectives of the present study were (a) to produce gluten-free bread, fortified with iron (GFB-Fe), using selected iron compounds (ferric pyrophosphate, ferric pyrophosphate with emulsifiers, NaFeEDTA, electrolytic iron, ferrous gluconate, ferrous lactate and ferrous sulphate) (b) to test sensory characteristics of the GFB-Fe (feel-mouth texture, crumb colour, aroma and taste) (c) to compare iron dialyzability of various iron compounds in GFB-Fe. The most acceptable products were those fortified with ferric pyrophosphate with emulsifiers and ferric pyrophosphate. Ferrous dialyzable iron (ferrous iron with molecular weight lower than 8000 Da, an index for prediction of iron bioavailability) was measured under simulated gastrointestinal conditions. Ferrous dialyzable iron in GFB-Fe fortified with ferric pyrophosphate with emulsifiers, NaFeEDTA, ferrous bis-glycinate, ferrous gluconate or ferrous sulphate was higher than that in GFB-Fe fortified with electrolytic iron, ferrous lactate or ferric pyrophosphate (P < 0.05). These results are promising for the development of GFB-Fe products in the future.     

Addition of milk or caseinophosphopeptides to fruit beverages to improve iron bioavailability?

A study has been made of the influence of caseinophosphopeptides (CPPs) added to a fruit beverage versus milk based fruit beverages upon iron retention, transport and uptake, using a combined simulated gastrointestinal digestion/Caco-2 cell system. Grape concentrate, orange concentrate, and apricot puree were used for sample formulation. Eight samples were assayed with/without added Fe sulphate (3 mg/100 ml fruit beverage) and/or added Zn sulphate (1.6 mg/100 ml fruit beverage), with/without skimmed milk (11% v/v). The addition of milk to fruit beverages exerted a positive effect on iron retention, transport and uptake versus fruit beverages, and this effect was greater than that of CPPs added to soluble fractions of fruit beverages. The addition of CPPs to soluble fractions of fruit beverages improved iron transport. Iron supplementation increased Fe retention, transport and uptake – the effect being more notable in samples with milk. Zinc supplementation did not affect Fe retention, transport or uptake.     

The quality of set‐style yoghurt responsible to partial lactose hydrolysis followed by protein cross‐linking of the skimmed milk

Skimmed milk used for set‐style yoghurt production was treated with lactase at 0.1 g/kg for 30 min to give partial lactose hydrolysis and then treated with horseradish peroxidase and glucose oxidase at 200 and 6 kU/kg protein to result in protein cross‐linking. Two treatments conferred higher apparent viscosity on the milk, but led to the yoghurt prepared from it with insignificantly different chemical compositions to the counterparts (P > 0.05). The prepared yoghurt also showed decreased syneresis (about 17.7%), higher apparent viscosity and viscoelastic modulus, firmer texture and finer microstructure. This ternary enzyme system is a potential approach to improving the quality of set‐style yoghurt.     

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     

Impact of fortification with iron salts and vitamin A on the physicochemical properties of laboratory‐pasteurised toned milk and bioaccessibility of the added nutrients

The sensory and physicochemical attributes of pasteurised milk fortified with soluble ferric pyrophosphate (FPP) (25 mg/L iron) and vitamin A (2500 IU) were comparable to unfortified control samples. The heat coagulation time (HCT) of fortified milks was comparable to the control and exhibited a type A curve with HCT–pH maxima at the acidic side of the natural pH. The distribution pattern of iron in different milk fractions was similar in control and fortified milk samples. The bioaccessibility of iron, estimated through in vitro digestibility of milk fortified with vitamin A and iron, was found to be slightly higher than that of milk fortified with iron alone.     

Influence of fortification with sodium–calcium caseinate and whey protein concentrate on microbiological,textural and sensory properties of set‐type yoghurt

The effect of fortification of yoghurt with sodium–calcium caseinate (SCC) and whey protein concentrate (WPC) on some properties of set‐type yoghurt were investigated. The addition of WPC enhanced the viability of Lactobacillus delbrueckii subsp. bulgaricus more than SCC. The highest firmness values were obtained from SCC‐fortified yoghurts, whereas yoghurts fortified with WPC had the highest water‐holding capacity during storage. The yoghurts fortified with 4% w/w SCC or 4% w/w WPC had the highest viscosity. Yoghurts fortified with 2% w/w SMP, SCC or WPC showed similar taste and overall acceptability scores; however, samples containing 4% w/w SCC or 4% w/w WPC had the lowest scores.     

Viscous and thermal behaviour of vitamin A and iron‐fortified reconstituted rice

The viscous and thermal behaviour of five types of micronutrient‐fortified reconstituted rice premixes extruded at pre‐optimised extrusion conditions (36% moisture content, 150 rpm screw speed and 89 °C barrel temperature) have been investigated using rapid visco analyser (RVA) and differential scanning calorimetry (DSC). The highest peak viscosity (1279 cP), lowest gelatinised starch percentage (16.32) and highest enthalpy of gelatinisation (8.2 J g^?1) were recorded in rice premix fortified with retinyl palmitate and micronised ferric pyrophosphate. The scanning electron microscopic analysis (SEM) also revealed that reconstituted rice premix fortified with iron (micronised ferric pyrophosphate) and retinyl palmitate was in closer resemblance to that of natural rice than any other reconstituted rice premix. The work demonstrated that vitamin A‐ and iron‐fortified reconstituted rice with meso/micro structure and pasting behaviour close to that of natural rice can be produced using retinyl palmitate and micronised ferric pyrophosphate as vitamin A and iron source, respectively.     

Preparation of iron‐fortified rice using edible coating materials

Iron‐fortified rice premix (IFRP) was prepared using soaking and spraying method followed by coating with hydroxypropyl methyl cellulose (HPMC), methyl cellulose (MC), combination of HPMC and MC, zein, palmitic acid (PA) and stearic acid (SA). Steaming caused a reduction in iron content in iron‐fortified rice premix than without steaming treatment. Iron content ranged from 1.33 to 7.11 and 1.61 to 4.49 mg g^?1, respectively, in IFRP prepared using soaking and spraying method. Retention of iron in IFRP samples coated with 9% PA, 7% and 9% SA, and combination of HPMC and MC at 2% level, respectively, after washing twice with distilled water was similar (P > 0.05). Retention of iron in these coated IFRP ranged from 87.34% to 89.39% (P > 0.05) as compared to 39.12% in uncoated IFRP. Sensory acceptability indicated the scope for the production of IFRP by spraying of iron solution with iron content 20.1 mg mL^?1, 180‐min tempering time and coating with 2% HPMC and MC followed by drying.     

Effect of Iron Fortification on Physical and Sensory Quality of Gluten-Free Bread

The scope of the present study was to investigate the effects of different iron compounds on the physical and sensory characteristics of gluten-free breads (GFBs) that were iron fortified (40 mg/kg solid compound) using different iron compounds. Differences among unfortified and fortified samples were observed in colour, crust firmness, and in the following sensory attributes: pore number, smell of ‘moisture’, metallic taste and stickiness. Elemental iron was more stable and thus adverse changes to product by its addition were not noticed. The results are useful in understanding the limitations of iron fortification and thus help designing more acceptable iron-fortified GFBs.     

Iron fortification of skim milk: Minerals and 57Fe Mössbauer study

Reconstituted skim milk was fortified at 2, 5, 10 and 20 mmol Fe kg^?1 with ferric and ferrous chloride iron with or without reversible acidification by injection of CO₂ under pressure. Carbonation improved transfer of iron from the soluble to the colloidal phase and accelerated ferrous iron oxidation. ⁵⁷Fe Mössbauer spectra of the freeze-dried casein micelles collected by centrifugation demonstrated that iron is present in a distorted octahedral coordination and is chelated by phosphate rather than citrate. Milk iron fortification induced several changes in the mineral component of the casein micelles, which are explained by the formation of a ternary complex: inorganic phosphate–iron–organic phosphate.     

Iron‐encapsulated cold‐set whey protein isolate gel powder – Part 1: Optimisation of preparation conditions and in vitro evaluation

A central composite design with a quadratic model was used to investigate the effects of three independent variables involved in the synthesis of iron‐encapsulated cold‐set whey protein isolate gel (WPI) on encapsulation efficiency (EE) and L*, a*, b* colour characteristics. The optimal conditions for maximum EE with minimum colour alteration were determined as 6.8% WPI, 18.8 mM iron and pH 7. In an in vitro gastrointestinal assay, only about 28% of the encapsulated iron was released in the gastric condition (with pepsin at pH 1.2), compared to 95% in the intestinal condition (with pancreatin at pH 7.5).     

Phytic acid and mineral micronutrients in field-grown chickpea (<Emphasis Type="Italic">Cicer arietinum</Emphasis> L.) cultivars from western Canada

Zinc (Zn), iron (Fe), magnesium (Mg), and calcium (Ca) in chickpea seed are important constituents in vegetarian diets. The aim was to investigate associations of these nutrients in different chickpea (Cicer arietinum L.) cultivars with phytic acid (PA), another naturally occurring constituent of grain that may influence the bioavailability of mineral micronutrients. Chickpea was grown at Saskatoon and Swift Current, SK, in 2002 and 2003, representing dryland production from high-yielding locations in western Canada. Minerals were measured by atomic absorption spectroscopy; PA was measured using high-performance anion-exchange conductivity detection methodology. Seed from 10 genotypes contained from 29 to 52 mg/kg Zn, 77–112 mg/kg Fe, 1,448–2,457 mg/kg Mg, 1,211–2,457 mg/kg Ca, to 3.8–9.0 mg/g PA. Phytic acid, Fe, Mg, and Ca decreased in 2003 from 2002 concentrations. Kabulis had greater Zn, the same Fe, but lower Mg and Ca concentrations than desi genotypes. Large-seeded genotypes had greater or the same Zn, the same Fe and Mg, but lower Ca than small-seeded genotypes. Iron and Ca concentrations positively correlated with PA concentration. Nutrients were affected by environment and genotype, which means that chickpea can be exploited by breeding, in addition to sourcing favorable nutritional profiles by environment, seed size, and market class.