In vitro bioaccessibility and bioavailability of iron from fenugreek, baobab and moringa

Bioaccessibility of carotenoids, tocochromanols, and iron from common bean (Phaseolus vulgaris L.) landraces

Common beans (Phaseolus vulgaris L.) are among the most important legumes for human nutrition. The aim of the present study was to characterize the composition and in vitro bioaccessibility of tocochromanols, carotenoids, and iron from 14 different landraces and 2 commercial common bean varieties. Phytic acid, dietary fiber, and total (poly)phenolic content were determined as factors that can modify the bioaccessibility of the studied compounds. Two carotenoids were identified, namely lutein (4.6-315 ng/g) and zeaxanthin (12.2-363 ng/g), while two tocochromanols were identified, namely γ-tocopherol (2.62-18.01 µg/g), and δ-tocopherol (0.143-1.44 µg/g). The iron content in the studied samples was in the range of 58.7-144.2 µg/g. The contents of carotenoids, tocochromanols, and iron differed significantly among the studied samples but were within the ranges reported for commercial beans. After simulated gastrointestinal digestion, the average bioaccessibility of carotenoids was 30 %, for tocochromanols 50 %, and 17 % for iron. High variability in the bioaccessible content yielded by the bean varieties was observed. Dietary fiber, phytic acid and total (poly)phenol contents were negatively correlated with the bioaccessibility of carotenoids, while iron bioaccessibility was negatively correlated with the total (poly)phenol content. The principal component analysis indicated that the bioaccessibility of lutein was the main variable involved in class separations. The composition of the food matrix plays an important role in the bioaccessibility of carotenoids, tocochromanols and iron from cooked beans.

Mapping every adult baobab (Adansonia digitata L.) across the Sahel and relationships to rural livelihoods

The baobab tree (Adansonia digitata L.) is an integral part of rural livelihoods throughout the African continent. However, the combined effects of climate change and increasing global demand for baobab products are currently exerting pressure on the sustainable utilization of these resources. Here we use sub-metre-resolution satellite imagery to identify the presence of nearly 2.8 million (underestimation bias 27.1%) baobab trees in the Sahel, a dryland region of 2.4 million km2. This achievement is considered an essential step towards an improved management and monitoring system of valuable woody species. Using Senegal as a case country, we find that 94% of rural buildings have at least one baobab tree in their immediate surroundings and that the abundance of baobabs is associated with a higher likelihood of people consuming a highly nutritious food group: dark green leafy vegetables. The generated database showcases the feasibility of mapping the location of single tree species at a sub-continental scale, providing vital information in times when deforestation and climate change cause the extinction of numerous tree species.

Ferrous Pyrophosphate and Mixed Divalent Pyrophosphates as Delivery Systems for Essential Minerals

Poorly water-soluble iron-containing compounds are promising iron fortificants. However, ensuring high bioaccessibility and low reactivity of iron is challenging. We present the potential application of ferrous pyrophosphate (Fe(II)PP) and Fe(II)-containing M2(1-x)Fe2x P2O7 salts (0 < x < 1, M = Ca, Zn, or Mn) for delivery of iron and a second essential mineral (M). After preparation by a facile and environment-friendly coprecipitation method, the salts were investigated for their composition, pH-dependent dissolution, iron-mediated discoloration of a black tea solution, and oxidation of vitamin C. Our results suggest that these salts are possible dual-fortificants with tunable composition that compared to Fe(II)PP (i) show lower (<0.5 mM) and enhanced (to 5 mM) iron dissolution in moderate and gastric pH, respectively, (ii) exhibit less discoloration and dissolved iron in tea when x = 0.470 for M = Ca or Zn and x = 0.086 for M = Mn, and (iii) do not increase the oxidation extent of vitamin C over 48 h when x = 0.06, 0.086, or 0.053 for M = Ca, Zn, or Mn, respectively.

Natural Extracts for Antibacterial Applications

Bacteria-induced epidemics and infectious diseases are seriously threatening the health of people around the world. In addition, antibiotic therapy has been inducing increasingly more serious bacterial resistance, which makes it urgent to develop new treatment strategies to combat bacteria, including multidrug-resistant bacteria. Natural extracts displaying antibacterial activity and good biocompatibility have attracted much attention due to greater concerns about the safety of synthetic chemicals and emerging drug resistance. These antibacterial components can be isolated and utilized as antimicrobials, as well as transformed, combined, or wrapped with other substances by using modern assistive technologies to fight bacteria synergistically. This review summarizes recent advances in natural extracts from three kinds of sources-plants, animals, and microorganisms-for antibacterial applications. This work discusses the corresponding antibacterial mechanisms and the future development of natural extracts in antibacterial fields.

The Impact of Moringa oleifera Supplementation on Anemia and other Variables during Pregnancy and Breastfeeding: A Narrative Review

Moringa is a plant commonly used for its medical properties. However, studies have shown contradictory results. The aim of this review is to evaluate the possible association between the use of Moringa during pregnancy and breastfeeding in relation to the health status of both the mother and the baby. A search of the PubMed and EMBASE databases on the literature published during the period 2018-2023 was conducted up until March 2023. The population/exposure/comparison/outcome (PECO) approach was used to select studies on pregnant women, mother-child pairs, and the use of Moringa. Out of the 85 studies initially identified, 67 were excluded, leaving 18 for full-text evaluation. After assessment, 12 were finally included in the review. In the articles included in this work, Moringa is administered during pregnancy or in the postnatal period in the form of leaf powder (MOLP), as a leaf extract (MLE), as an ingredient associated with other supplements or in preparations. It appears to influence several variables during pregnancy and in the postnatal period such as the mother's haematochemical profile, milk production, the child's socio-personal development and the incidence of morbidity during the first 6 months of life. None of the studies analysed reported contraindications to the use of the supplement during pregnancy and lactation.

Edible Halophytes with Functional Properties: In Vitro Protein Digestibility and Bioaccessibility and Intestinal Absorption of Minerals and Trace Elements from Australian Indigenous Halophytes

Halophytes are considered emerging functional foods as they are high in protein, minerals, and trace elements, although studies investigating halophyte digestibility, bioaccessibility, and intestinal absorption are limited. Therefore, this study investigated the in vitro protein digestibility, bioaccessibility and intestinal absorption of minerals and trace elements in saltbush and samphire, two important Australian indigenous halophytes. The total amino acid contents of samphire and saltbush were 42.5 and 87.3 mg/g DW, and even though saltbush had a higher total protein content overall, the in vitro digestibility of samphire protein was higher than the saltbush protein. The in vitro bioaccessibility of Mg, Fe, and Zn was higher in freeze-dried halophyte powder compared to the halophyte test food, suggesting that the food matrix has a significant impact on mineral and trace element bioaccessibility. However, the samphire test food digesta had the highest intestinal Fe absorption rate, whereas the saltbush digesta exhibited the lowest (37.7 vs. 8.9 ng/mL ferritin). The present study provides crucial data about the digestive "fate" of halophyte protein, minerals, and trace elements and increases the understanding of these underutilized indigenous edible plants as future functional foods.

Gum Arabic-Stabilized Ferric Oxyhydroxide Nanoparticles for Efficient and Targeted Intestinal Delivery of Bioavailable Iron

Nanostructured iron(III) compounds are promising food fortificants with desirable iron bioavailability and food compatibility. Here, gum arabic (GA) solubilized 252 mg of iron(III) per g at neutral pH in the form of GA-stabilized ferric oxyhydroxide nanoparticles (GA-FeONPs) with Z-average size of 142.7 ± 5.9 nm and ζ-potential of -20.50 ± 1.25 mV. Calcein-fluorescence-quenching assay revealed well-absorbed iron from GA-FeONPs by polarized Caco-2 cells due to efficient macropinocytic internalization and asialoglycoprotein receptor-mediated specific endocytosis facilitated by the polypeptide and arabinogalactan fractions of GA, respectively, with endocytosed GA-FeONPs being in part basolaterally transcytosed and in another part degraded into cellular labile iron pool. GA-FeONPs showed good colloidal stability under varied pH, gastrointestinal, thermal processing, and spray/freeze drying conditions and displayed remarkably weaker pro-oxidant activity than FeSO₄ in glyceryl trilinoleate emulsion (P < 0.05). Oral pharmacokinetics unveiled desirable iron bioavailability of GA-FeONPs relative to FeSO₄, i.e., 124.27 ± 5.91% in aqueous solution and 161.64 ± 5.01% in milk. Overall, GA-FeONPs are a promising novel iron fortificant with food-compatible, efficient, and targeted intestinal iron delivery and sustained iron-release properties.

Can consumption of local micronutrient- and absorption enhancer-rich plant foods together with starchy staples improve bioavailable iron and zinc in diets of at-risk African populations?

Iron and zinc deficiencies remain prevalent in developing countries, often due to monotonous starchy diets that are low in bioavailable minerals. This review addresses the question as to whether consumption of starchy staple foods in Africa together with micronutrient-dense and absorption enhancer-rich plant foods can enhance iron and zinc bioavailability in the diets of at-risk populations. While green leafy vegetables (GLVs) fortification of starchy staples can improve mineral contents, especially iron, it may not improve bioavailable iron and zinc, due to GLVs' high contents of mineral absorption inhibitors, notably polyphenols, phytate and calcium. Fruits, although low in minerals, could improve bioavailable iron and zinc in the staples because of their high ascorbic and citric acid and/or β-carotene contents, which can form soluble chelates with the minerals. More human studies are needed to establish whether such a technology or fortification strategy can improve bioavailable iron and zinc in African-type plant-based diets.

Nutritional and techno-functional properties of Australian Acacia seed flour: Effects of roasting on chemical composition, physicochemical properties, and in vitro digestibility and intestinal iron absorption

Acacia seed (AS) is rich in protein and iron but contains protease inhibitors that can reduce protein digestibility (PD). The seeds are generally roasted prior to consumption, although no information on the PD of roasted AS is available. This study investigated the effect of roasting time (5, 7 and 9 min at 180 °C) on the chemical composition, physicochemical properties, and in vitro PD and intestinal iron absorption of three wild harvested Australian AS species, Acacia victoriae, A. coriacea and A. cowleana. Roasting A. victoriae and A. coriacea seeds for 7 min significantly increased PD in the seeds by 36 and 61 %, respectively. A 9-min roasting time was required to achieve 75 % reduction in trypsin inhibitor activity in A. coriacea seed, while a shorter roasting time (RT) was sufficient to achieve similar reduction rates in the other two Acacia species. Among the functional properties, water and oil absorption capacities were significantly enhanced as RT increased. The starch granules in 7- and 9-min roasted A. victoriae seed flour detached from the protein matrix while random coil increased in 7-min roasted A. victoriae and 9-min roasted A. coriacea and A. cowleana, thus, contributing to enhanced PD. Although the SDS-PAGE in 7- and 9-min roasted A. cowleana samples showed reductions in the intensity of bands for high molecular weight proteins, PD was not affected by RT. However, intestinal iron absorption was not significantly affected by roasting as compared to raw digesta samples. Compared to commercial roasted Acacia seed, the considerably shorter RT used in this study improved PD in the AS flour with less adverse effects on techno-functional properties.

Iron Absorption: Factors, Limitations, and Improvement Methods

Iron is an essential element for human life since it participates in many functions in the human body, including oxygen transport, immunity, cell division and differentiation, and energy metabolism. Iron homeostasis is mainly controlled by intestinal absorption because iron does not have active excretory mechanisms for humans. Thus, efficient intestinal iron bioavailability is essential to reduce the risk of iron deficiency anemia. There are two forms of iron, heme and nonheme, found in foods. The average daily dietary iron intake is 10 to 15 mg in humans since only 1 to 2 mg is absorbed through the intestinal system. Nutrient-nutrient interactions may play a role in dietary intestinal iron absorption. Dietary inhibitors such as calcium, phytates, polyphenols and enhancers such as ascorbic acid and proteins mainly influence iron bioavailability. Numerous studies have been carried out for years to enhance iron bioavailability and combat iron deficiency. In addition to traditional methods, innovative techniques are being developed day by day to enhance iron bioavailability. This review will provide information about iron bioavailability, factors affecting absorption, iron deficiency, and recent studies on improving iron bioavailability.

Polyphosphates as an effective vehicle for delivery of bioavailable nanoparticulate iron(III)

Polyphosphates are widely used food additives with the potential to increase iron bioavailability but chemical nature of their soluble complexes with iron remains largely unknown. Here, pyrophosphate, tripolyphosphate, hexametaphosphate and ∼25-chain-length polyphosphate solubilized 896, 896, 1120 and 1344 mg Fe(III) per g, respectively, at neutral pH by mediating the formation of highly-negatively-charged ferric hydroxide-polyphosphate nanoparticles (PolyP-FeONPs). PolyP-FeONPs displayed fading yellow color with increasing initial dissolved P/Fe ratio ((P/Fe)_init) and decreasing polyphosphate length due to rising proportion of Fe(III)-phosphate bonds, and specifically, pyrophosphate resulted colorless PolyP-FeONPs at (P/Fe)_init ≥ 4. PolyP-FeONPs had weak pro-oxidant activity in glyceryl trilinoleate emulsion and good colloidal stability under spray/freeze-drying and gastrointestinal conditions. Serum iron kinetics in rats revealed sustained iron release and ∼170% iron bioavailability of oral PolyP-FeONPs relative to FeSO₄. Calcein-fluorescence-quenching assay in polarized Caco-2 cells unveiled divalent-metal-transporter-1-independent and macropinocytosis-dependent iron uptake from PolyP-FeONPs. This study helps develop food-compatible, highly-bioavailable and sustained-release iron preparations.

A Narrative Review: In-vitro Methods for Assessing Bio-Accessibility/Bioavailability of Iron in Plant-Based Foods

In-vitro measurement has the advantage of rapid and convenient method of screening the iron bioavailability within the range of plant-based foods. It is important to do preliminary screening as it provides information which will be useful to identify promising plant sources of iron before moving to human trials. A review on in-vitro methods of bio-accessibility and bioavailability of iron in plant-based foods including fruits, vegetables, cereals and legumes is entailed here. The review will focus on in-vitro methods of iron bioavailability in plant-based foods and the effects of inhibitors and processing on the iron bioavailability. The variation of the methods and updates on a recent INFOGEST method used to measure the bioavailability of iron in plant-based foods will also be discussed.

A colorimetric and fluorescence dual-signal determination for iron (II) and H2O2 in food based on sulfur quantum dots

A colorimetric and fluorescence dual-signal method based on sulfur quantum dots (SQDs) was established for determination of iron (II) (Fe²⁺) and H₂O₂ in foods. Due to the complexation of Fe²⁺ with SQD, Fe²⁺ can cause fluorescence quenching of SQDs, and the color of the mixed solution changed from light yellow to deep green. By use of Fenton reaction, H₂O₂ can restore the quenched fluorescence of SQDs, and the color of the mixture changed from green to colorless. The concentration of Fe²⁺ and H₂O₂ has a good linear relationship with the fluorescence intensity and absorbance in the range of 2.5-55 μM and 1.25-500 μM, and the detection limits were 1.41 μM and 0.54 μM, respectively. For determination of H₂O₂, the linear ranges were 1.17-1.97 mM and 0.867-1.50 mM, and the detection limits were 0.03 μM and 0.06 μM, respectively.

Bioavailability of iron from novel hydrogen reduced iron powders: Studies in Caco-2 cells and rat model

The bioavailability of iron from elemental iron powders, including hydrogen reduced iron powder (HRIP), is influenced by particle size and surface area. In the present study, we investigated the solubility, bioaccessibility, and bioavailability of iron from novel HRIPs (particle size ≤25 and 38 µm generated at low [LT] and high [HT] temperature), with porous morphology and high surface area, in intestinal Caco-2 cells and in rat models. The acceptability of fortified wheat flour was tested in human volunteers. The iron solubility and ferritin induction in Caco-2 cells were significantly higher from wheat flour fortified with HRIPs compared to electrolytic iron powder (EIP, ≤45 µm size) either in the absence or presence of ascorbic acid. Nevertheless, ferritin induction in Caco-2 cells was significantly higher with FeSO₄ compared to HRIP or EIP. The relative biological value of HRIPs was significantly higher (≤38HT) or similar compared to EIP in rats. However, serum ferritin was significantly higher in rats fed HRIPs than EIP. Further, wheat flour fortified with HRIP was found to be acceptable for consumption. These findings demonstrate higher iron bioavailability from novel HRIPs compared to the reference EIP (≤45 µm) and merits further studies on toxicity and efficacy. PRACTICAL APPLICATION: The use of elemental iron powders for food fortification to alleviate iron deficiency is limited due to its poor bioavailability. The novel hydrogen-reduced elemental iron powders used in this study had higher bioaccessibility and bioavailability compared to reference EIP (≤45 µm) in in vitro and in vivo models, respectively. Further, there were no sensory differences between roti prepared with fortified or unfortified wheat flour. These results suggest that the novel hydrogen reduced elemental iron powders used in the present study are suitable for wheat flour fortification.

Potential of moringa leaf and baobab fruit food-to-food fortification of wholegrain maize porridge to improve iron and zinc bioaccessibility

Food-to-food fortification (FtFF) with moringa leaf (iron source) and/or baobab fruit (citric acid and ascorbic acid source) (each 13-15 g/100 g porridge dry basis (db)) was studied to improve iron and zinc nutritive quality in African-type wholegrain maize-based porridges using in vitro dialysability assay. Moringa FtFF decreased percentage and total bioaccessible iron and zinc, by up to 84% and 45%, respectively. Moringa was very high in calcium, approximately 3% db and calcium-iron-phytate complexes inhibit iron bioavailability. Baobab FtFF increased percentage and total bioaccessible iron and zinc, especially in porridges containing carrot + mango (β-carotene source) and conventionally fortified with FeSO₄, by up to 111% and 60%, respectively. The effects were similar to those when ascorbic and citric acids were added as mineral absorption enhancers. While moringa FtFF could be inhibitory to iron and zinc bioavailability in cereal-based porridges, baobab fruit FtFF could improve their bioavailability, especially in combination with conventional iron fortification.