Effect of Glycosylation on the Physicochemical Properties,Structure and Iron Bioavailability of Ferritin Extracted from Tegillarca granosa

Iron deficiency anemia(IDA)is a major global health problem.Tegillarca granosa has been considered as an excellent source of iron given its high content of iron-binding protein,ferritin.The aim of the present study was to determine the physicochemical properties,protein structures,and iron uptake of ferritin extracted from T.granosa,and to evaluate the potential impacts of chitosan glycosylation on these characteristics.Based on Box-Behnken design and response surface methodology,the optimal conditions for glycosylation included a ferritin/chitosan mass ratio of 4:1,a pH of 5.5,a reaction time of 10 min,and a reaction temperature of 50℃.Glycosylation caused decreased surface hydrophobicity and elevated water-holding capacity of ferritin due to the introduction of hydrophilic groups.Additionally,glycosylation improved antioxidant capacity of ferritin by 20.69%–189.66%,likely owing to the protons donated by saccharide moiety to terminate free radical chain reaction.The in vitro digestibility of ferritin was elevated by 22.56%–104.85%after glycosylation,which could be associated with lessβ-sheet content in secondary structure that made the glycosylated protein less resistant to enzymatic digestion.The results of the iron bioavailability in Caco-2 cells revealed that ferritin(78.85–231.77 ngmg^(−1))exhibited better iron bioavailability than FeSO4(51.48–114.37 ngmg^(−1))and the values were further elevated by glycosylation with chitosan(296.23–358.20 ngmg^(−1)),which may be related to the physicochemical properties of ferritin via glycosylation modification.These results provide a basis for the development of T.granosa derived ferritin and its glycosylated products,and can promote the utilization of aquatic resources.

Assessment of Iron Bioavailability in Ten Kinds of Chinese Wheat Flours Using an in vitro Digestion/Caco-2 cell Model

Abstract Objective To compare iron bioavailability （Fe BV） from ten selected kinds of Chinese wheat flours in order to provide scientific basis for further human trials and enable plant breeding programs to screen biofortified wheat cultivars. Methods An in vitro digestion/Caco-2 cell model was used to assess Fe BV of ten flour samples from six leading Chinese wheat cultivars and the stability of Fe BV in one cultivar was studied across three growing environments. Results Significant differences were observed in both Fe BV and Fe bioavailability per gram of food （Fe BVPG） among cultivars （P〈0.01） grown at the same location with the same flour extraction rate. Zhongyou 9507 and Jingdong 8 had Fe BV 37%-54% and Fe BVP（3 103%-154% higher than the reference control. In the Anyang environment, Zhongyou 9507 had a higher wheat flour-Fe level and Fe BVPG. Differences in Fe BV were detected in cultivars with different flour extraction rates. Conclusion Zhongyou 9507 and Jingdong 8 were identified as the most promising cultivars for further evaluation of efficacy by using human subjects. The growing environments had no effect on Fe BV, but did have a significant effect on Fe BVPG. Fe bioavailabilities in low-extraction （40%） flours were higher than those in high-extraction （78%） flours.

Inaccuracies in Phytic Acid Measurement: Implications for Mineral Biofortification and Bioavailability

Biofortification of commonly eaten staple food crops with essential mineral micronutrients is a potential sustainable solution to global micronutrient malnutrition. Because phytic acid (PA;1,2,3,4,5,6-hexakis myo-inositol) reduces mineral micronutrient bioavailability, reduction of PA levels could increase the bioavailability of biofortified iron (Fe), zinc (Zn), calcium (Ca), and magnesium (Mg). PA is viewed as an anti-nutrient, yet PA and other inositol phosphates have also demonstrated positive health benefits. Phytic acid analysis in the agricultural, food, and nutritional sciences is typically carried out by colorimetry and chromatographic techniques. In addition, advanced techniques such as nuclear magnetic resonance and synchrotron X-ray absorption spectroscopy have also been used in phytic acid analysis. The colorimetric analysis may overestimate PA levels and synchrotron X-ray absorption techniques may not detect very low levels of inositol phosphates. This short communication discusses the advantages and disadvantages of each widely used phytic acid analysis method, and suggests high performance anion exchange (HPAE) chromatography with conductivity detection (CD) based analysis can achieve greater accuracy for the identification and quantification of inositol phosphates. Accurate characterization and quantification of PA and inositol phosphates will inform PA reduction and biofortification efforts, allowing retention of the benefits of non-phytic inositol phosphates for both plants and humans.

Can Improve Iron Biofortification Antioxidant Response,Yield and Nutritional Quality in Green Bean?

The aim of this study was to evaluate the effect of iron biofortification on antioxidant response, yield and nutritional qualityof green bean (Phaseolus vulgaris L.) under greenhouse conditions. Fe was applied using two forms (FeSO4 and Fe-EDDHA) at four doses of application (0, 25, 50 and 100 μm) added under a hydroponic system, and were tested over a period of 40 days. The Fe content was assessed in seeds, as well as the activity of antioxidant enzymes, production of H2O2, yield and nutritional quality. The results being obtained indicated that the accumulation of Fe in bean seeds enhanced with the application of Fe-EDDHA at the dose of 25 μm. This demonstrated that low Fe application dose was enough to increase Fe levels in seeds of common bean. In addition, Fe-EDDHA application form at 50 μmol was the best treatment to improve crop yield. Respect to antioxidant system, chelated form of Fe (Fe-EDDHA) was more effective in the activation of antioxidant enzymes (CAT, SOD and GSH-PX), and a lower content of H2O2 in green bean seeds. Finally, to raise the Fe concentration in bean under biofortification program was a promising strategy in cropping systems in order to increase the ingestion of iron and antioxidant capacity in the general population and provided the benefits that this element offered in human health.

Next Generation Nutrition: Genomic and Molecular Breeding Innovations for Iron and Zinc Biofortification in Rice

Global efforts to address malnutrition and hidden hunger, particularly prevalent in low- and middle-income countries, have intensified, with a focus on enhancing the nutritional content of staple crops like rice. Despite serving as a staple for over half of the world's population, rice falls short in meeting daily nutritional requirements, especially for iron(Fe) and zinc(Zn). Genetic resources, such as wild rice species and specific rice varieties, offer promising avenues for enhancing Fe and Zn content. Additionally, molecular breeding approaches have identified key genes and loci associated with Fe and Zn accumulation in rice grains. This review explores the genetic resources and molecular mechanisms underlying Fe and Zn accumulation in rice grains. The functional genomics involved in Fe uptake, transport, and distribution in rice plants have revealed key genes such as OsFRO1, OsIRT1, and OsNAS3. Similarly, genes associated with Zn uptake and translocation, including OsZIP11 and OsNRAMP1, have been identified. Transgenic approaches, leveraging transporter gene families and genome editing technologies, offer promising avenues for enhancing Fe and Zn content in rice grains. Moreover, strategies for reducing phytic acid(PA) content, a known inhibitor of mineral bioavailability, have been explored, including the identification of low-PA mutants and natural variants. The integration of genomic information, including whole-genome resequencing and pan-genome analyses, provides valuable insights into the genetic basis of micronutrient traits and facilitates targeted breeding efforts. Functional genomics studies have elucidated the molecular mechanisms underlying Fe uptake and translocation in rice. Furthermore, transgenic and genome editing techniques have shown promise in enhancing Fe and Zn content in rice grains through the manipulation of key transporter genes. Overall, the integration of multi-omics approaches holds significant promise for addressing global malnutrition and hidden hunger by enhancing the nutritional quality of rice, thereby contributing to improved food and nutritional security worldwide.

Provitamin A Crops: Acceptability, Bioavailability, Efficacy and Effectiveness

Vitamin A deficiency (VAD) is the world’s commonest cause of childhood blindness. More than half of these cases occur in developing countries. Animal sourced foods though good sources of vitamin A are too expensive for poor rural people. Crops biofortified with provitamin A offer a convenient and accessible source of vitamin A. The other micro-nutrient programs of fortification and supplementation require more expensive inputs. Biofortification programs have developed crops that are rich in provitamin A. These crops include: maize, golden rice, cassava and orange fleshed sweetpotato (OFSP). With exception of golden rice, the rest of the biofortified crops have received considerable acceptance among the communities. Both animal and human studies have shown that provitamin A from biofortified crops is highly bioavailable and have capacity to improve vitamin A status. After several years of research and promotion, it is time to fully commercialize provitamin A crops by encouraging farmers to start their large scale production and consumption.

Application of Zinc, Iron and Boron Enhances Productivity and Grain Biofortification of Mungbean

Deficiencies of essential vitamins,iron(Fe),and zinc(Zn)affect over one-half of the world’s population.A significant progress has been made to control micronutrient deficiencies through supplementation,but new approaches are needed,especially to reach the rural poor.Agronomic biofortification of pulses with Zn,Fe,and boron(B)offers a pragmatic solution to combat hidden hunger instead of food fortification and supplementation.Moreover,it also has positive effects on crop production as well.Therefore,we conducted three separate field experiments for two consecutive years to evaluate the impact of soil and foliar application of the aforementioned nutrients on the yield and seed biofortification of mungbean.Soil application of Zn at 0,4.125,8.25,Fe at 0,2.5,5.0 and B at 0,0.55,1.1 kg ha−1 was done in the first,second and third experiment,respectively.Foliar application in these experiments was done at 0.3%Zn,0.2%Fe and 0.1%B respectively one week after flowering initiation.Data revealed that soil-applied Zn,Fe and B at 8.25,5.0 and 1.1 kg ha−1,respectively,enhanced the grain yield of mungbean;however,this increase in yield was statistically similar to that recorded with Zn,Fe and B at 4.125,2.5 and 0.55 kg ha−1,respectively.Foliar application of these nutrients at flower initiation significantly enhanced the Zn contents by 28%and 31%,Fe contents by 80%and 78%,while B contents by 98%and 116%over control during 2019 and 2020,respectively.It was concluded from the results that soil application of Zn,Fe,and B enhanced the yield performance of mungbean;while significant improvements in seed Zn,Fe,and B contents were recorded with foliar application of these nutrients.

Soil Manganese and Iron Released due to Calcium Salts:Bioavailability to Pepper (Capsicum frutescens L.)

Releases of manganese and iron ions from an albic soil (Albic-Udic Luvisol), a yellow-red soil (Hap-Udic Ferrisol) and a yellow-brown soil (Arp-Udic Luvisol) induced by calcium salt addition and their bioavailability to pepper (Capsicum frutescens L.) were studied in a pot experiment. Addition of Ca(NO3)2 decreased soil pH and increased both exchangeable and DTPA (diethylenetriamine pentaacetic acid)-extractable Mn and Fe in soils. Meanwhile, total Mn accumulation in the shoots of Capsicum frutescens L. on the salt-treated soils increased significantly (P ＜ 0.01) compared with the control, suggesting that salt addition to soil induced Mn toxicity in Capsicum frutescens L. Although exchangeable and DTPA-extractable Fe increased also in the salt-treated soils, Fe uptake by the shoots of Capsicum frutescens L. decreased. The effect of added salts in soils on dry matter weight of pepper varied with the soil characteristics, showing different buffer capacities of the soils for salt toxicity in an order of yellow-brown soil ＞ albic soil ＞ yellow-red soil. Fe/Mn ratio in shoots of Capsicum frutescens L. decreased with increasing salt addition for all the soils, which was ascribed to the antagonistic effect of Mn on Fe accumulation. The ratio of Fe/Mn in the tissue was a better indicator of the appearance of Mn toxicity symptoms than Mn concentration alone.

Iron oxidation-reduction bioavailability in and its impacts on cadmium paddy soils： a review

Redox conditions in paddy soils may vary as they are submerged and drained during rice growth. This change may bring about reductive dissolution of iron （Fe） oxides and subsequent formation of secondary Fe-bearing minerals in rice paddies. The mobility and bioavailability of metal contaminants such as cadmium （Cd） in paddy soils are closely related to the chemical behaviors of Fe. Therefore, in this paper, advances in the study of paddy Fe redox transformations and their effects on Cd availability to rice are briefly reviewed. Current concepts presented in this review include the forms of Fe in paddy soils, the reactions involved in Fe oxidation-reduction, chemical factors affecting Fe redox processes, Cd availability to rice and the impacts of Fe transformation on Cd uptake and translocation in rice. Prospects for future research in this area are also discussed.

Bioavailability of Iron and Related Components in Cooked Green Leafy Vegetables Consumed in Cameroon

Green leafy vegetables (GLVs) are a potential source of iron to combat iron deficiency in iron deficient population. The aim of this study was to determine the bioavailability of iron in seven species of leafy vegetables (Solanumscrabrun, Venonia amygdalina, Cucurbita maxima, Amarathus hybridus, Colococia esculenta, Solanum macrocarpon and Telfairia occidentalis) consumed in Bamenda, Cameroon. A survey was carried out in 70 households in Bamenda, Cameroon to determine methods of preparation of these green leafy vegetables. Iron, antinutrients and vitamin C levels were determined using standard methods and the bioavailability of iron was determined using an in vitro dialys ability method. The vegetables used for the study were cooked with the addition of tomatoes, peanuts, melon seeds and soybean seeds. The loss of iron in GLVs was as a result of dilution caused by addition of the principal ingredients. The V. amygdalina cooked with soybean contained the highest level of iron (128.28 mg/100g). The S. scrabrum cooked with tomatoes had the highest Total phenolic coumponds of 0.91 g/100g;the C. esculenta recorded the highest with values ranging between 0.14 - 0.35 g/100g;the C. maxima cooked with soybean recorded the highest oxalate level (6.46 g/100g);and the vegetables cooked with melon seeds recording the highest in phytatelevels (70 - 1.63 g/100g). Vitamin C levels were highest in the S. macrocarpon cooked with tomatoes (199.96 mg/100g). Iron bioavailability was highest in A. hybridus cooked with tomatoes (28.09%). The iron bioavailability negatively correlated with phytates and positively with vitamin C. GLV consumed in Bamenda are good sources of iron whose bioavailability can be improved by using tomatoes in cooking.

FeSO_(4)对水稻根表铁膜及污染稻田土中镉迁移转运影响研究

选取湖南某污染稻田耕作层土壤,通过盆栽实验外源施加硫酸亚铁(FeSO_(4)),研究FeSO_(4)对水稻根表铁膜及污染稻田土中镉(Cd)迁移转运的影响。结果表明,随着FeSO_(4)施加量增加(0~320 mg/kg),水稻根际土壤pH值呈下降趋势,最高下降了0.70;水稻盆栽土壤TCLP-Cd含量与对照组相比出现一定程度上升;施加FeSO_(4),降低了水稻茎叶、谷壳、糙米中Cd含量,增加了水稻植株根表铁膜的数量,一定程度上控制了水稻对土壤中Cd的吸收。但施加外源铁影响了土壤pH值及Cd的生物有效性,在实际稻田施加FeSO_(4)时建议与石灰等其他碱性修复材料进行组配,以获得更好的阻控效果。

食源性肽铁螯合物研究进展

铁元素是人体维持红细胞代谢、辅助骨髓造血的必需营养素。铁元素的缺乏会引起多种疾病,如贫血、发育不良、孕妇早产等。肽铁螯合物作为一种新兴的补铁产品,因其具有吸收率高、安全无副作用等优点,近年来逐渐被当成新型的理想补铁剂。本文主要综述了食源性肽及肽铁螯合物的制备及其螯合活性影响因素,归纳肽铁结合机制,对其结合位点和螯合模式进行了概括,进一步分析其构象变化和分子间作用力,并总结其促进铁生物利用度的方式,旨在为肽铁螯合物在功能性食品、新型补铁剂上的开发应用提供参考。

Phytate:impact on environment and human nutrition.A challenge for molecular breeding

Phytic acid (PA) is the primary storage compound of phosphorus in seeds accounting for up to 80% of the total seed phosphorus and contributing as much as 1.5% to the seed dry weight. The negatively charged phosphate in PA strongly binds to metallic cations of Ca, Fe, K, Mg, Mn and Zn making them insoluble and thus unavailable as nutritional factors. Phytate mainly accumulates in protein storage vacuoles as globoids, predominantly located in the aleurone layer (wheat, barley and rice) or in the embryo (maize). During germination, phytate is hydrolysed by endogenous phytase(s) and other phosphatases to release phosphate, inositol and micronutrients to support the emerging seedling. PA and its derivatives are also implicated in RNA export, DNA repair, signalling, endocytosis and cell vesicular trafficking. Our recent studies on purification of phytate globoids, their mineral composition and dephytinization by wheat phytase will be discussed. Biochemical data for purified and characterized phytases isolated from more than 23 plant species are presented, the dephosphorylation pathways of phytic acid by different classes of phytases are compared, and the application of phytase in food and feed is discussed.

不同锌源叶面喷施对冬小麦和夏玉米产量及籽粒营养品质的影响

为探明不同锌源叶面肥喷施对小麦和玉米产量、籽粒矿质元素含量及锌、铁生物有效性的影响,对冬小麦-夏玉米轮作体系开展不同叶面肥喷施试验。小麦季设置去离子水(CK1)、尿素(CK2)、尿素+纳米氧化锌(U+ZnO)、尿素+壳聚糖纳米锌(U+ZnCNP)、尿素+普通七水硫酸锌(U+Zn)5种叶面肥处理;玉米季增加尿素与锌铁硒多元混合喷施处理(U+Zn/Fe/Se)。结果表明:各叶面肥喷施处理对小麦和玉米籽粒产量均无显著影响,但对籽粒微量元素含量有显著影响。不同锌源与尿素混合叶面肥对小麦籽粒锌含量强化效果由弱到强依次为U+ZnCNP<U+ZnO<U+Zn。与CK2处理相比,处理U+Zn使小麦籽粒锌含量显著提高77.7%(从22.80 mg·kg^(-1)增加至40.52 mg·kg^(-1))、籽粒植酸与锌(PA/Zn)摩尔比显著下降42.1%,使籽粒锌生物有效性(TAZ)显著提高74.5%。对于玉米,与CK2处理相比,处理U+Zn/Fe/Se使籽粒锌含量提高32.3%(从14.93 mg·kg^(-1)增加至19.60 mg·kg^(-1))、硒含量显著提高12.7倍(从17.66μg·kg^(-1)增加至242.04μg·kg^(-1))、籽粒PA/Zn摩尔比显著下降27.0%,使籽粒TAZ显著提高36.9%,使整个植株或玉米秸秆磷与锌(P/Zn)和磷与铁(P/Fe)摩尔比降低。研究表明,叶面喷施普通七水硫酸锌是提高小麦、玉米籽粒锌含量和生物有效性的最佳形式,其强化小麦籽粒锌效果优于玉米。叶面喷施尿素与锌铁硒混合溶液可同时提高玉米籽粒锌、硒含量及锌、铁生物有效性(籽粒、全株、秸秆),是解决人体或动物微量元素营养缺乏的有效农艺强化措施。

Effects of Lean Beef Supplementation on Iron Status, Body Composition and Performance of Collegiate Distance Runners

Iron deficiency is prevalent among endurance athletes, particularly females. Low iron may compromise oxygen delivery and physical performance. Vegetarianism, desire for convenience, and perceived health risks associated with red meat contribute to low bioavailable iron intakes. The purpose of this study was to examine if lean beef supplementation would maintain iron status, improve body composition and increase performance of distance runners after 8 weeks. Twenty-eight (14 female) Division-I cross-country runners were stratified by iron status, use of iron supplements, and gender, and randomized into a control (n = 14) and intervention group. All participants maintained their typical diet and consumed a daily multivitamin, while the intervention group consumed 9 ounces of lean beef weekly. Dietary intake (total iron, heme-iron, protein, zinc), body composition, VO2max, and iron status (hemoglobin, hematocrit, serum iron, serum ferritin, total iron binding capacity [TIBC]) were measured at baseline and post-intervention. The intervention group had greater intakes of total and heme-iron. There were no group differences in amino acids, protein, or calories. Both groups had a significant body fat increase and lean mass decease over time. There was a significant VO2max increase over time in both groups. There were no group differences due to the intervention in serum ferritin, hemoglobin, serum iron, and TIBC. There was a significant difference in hematocrit between groups as a result of the intervention. In conclusion, increasing bioavailable iron from red meat may have effects on body composition and maintenance of blood iron markers;however, its direct impact on performance among endurance athletes is unclear.

Influence of Potassium Nutrition and Exogenous Organic Acids on Iron Uptake by Monocot and Dicot Plants

Iron (Fe) is a vital element for the survival and proliferation of all plants;therefore, Fe-biofortification by the application of chemical and organic fertilizers is being as an effective approach to fight hidden hunger retards the growth and development of crop plants. Two experiments were carried out to investigate the effect of potassium and exogenous organic acids on iron uptake by two different plants: one is monocotyledon, maize (Zea mays L.) and the second is dicotolydon pea (Pisum sativum L.) grown under controlled conditions. The seedlings were grown in sand culture in a greenhouse experiment and irrigated with one-tenth strength modified nutrient solution of Hoagland and Arnon as a base solution (pH 7.5), containing different iron treatments (0, 1, and 5 ppm as FeSO4·7H2O) combined with potassium nutrition (0, 5, 10, and 50 ppm as K2SO4). After 30 days, the best interaction treatment was selected for further experiment including 5.0 ppm Fe as FeSO4.7H2O and 50 ppm K as K2SO4 in combination with 1 × 10-5 mole/liter of one of the following organic acids: Citric acid, Oxalic acid, Formic acid, Acetic acid, Propionic acid, Tartaric acid, Succinic acid, Fumaric acid, Malic acid, Glutamic acid, besides the free organic acid nutrient solution as a control. Results revealed that the interaction between 5.0 ppm Fe and 50 ppm K was the best interaction treatment for increasing biomass production and iron uptake of maize and pea seedlings under applied condition. Furthermore, exogenous application of organic acids improves uptake and translocation of nutrient such as iron, potassium and phosphorus by the maize and pea plants. In conclusion, potassium nutrition and exogenous organic acids have the potential to stimulate Fe-uptake of monocot and dicot plants and mediate iron-biofortified crops.

生物源新型铁螯合剂研究进展及其应用

铁是所有生物正常发育所必需的微量元素之一,尤其是通过生物强化培育富含铁营养的农产品是解决人类铁营养“隐性饥饿”的重要技术途径,而螯合态铁肥由于见效快被广泛应用。因此,创制和研发新型微量元素螯合剂始终是国内外研究的竞争热点。麦根酸类植物铁载体和微生物铁载体等,能够高效螯合难溶铁并被植物高效吸收利用,是潜在的新型生物源螯合剂。该类新型铁肥在改善植物铁营养的同时不需要外源铁的投入,而是发挥菌株自身活性物质较强的螯合特性高效活化土壤中丰富的铁资源,为植物提供足够的生物有效铁。为进一步挖掘和研发新型生物源的绿色、高效且稳定的螯合剂,并为绿色智能肥料研发、实现绿色农业的可持续发展提供新途径和技术突破,本文基于近年来植物和微生物对铁营养吸收利用的分子生理机制的不断深入研究,从植物缺铁现状及诱因、改善铁营养的途径,到机理Ⅱ植物根系分泌物吸收利用铁的分子生态优势以及微生物铁载体改善植物铁营养的潜力,对生物源新型铁螯合剂研究进展及其应用进行了系统综述。期望通过进一步的研究和开发,能够更深入地了解这些新型生物源螯合剂的作用机制以提高植物的铁营养吸收效率,为实现绿色农业的可持续发展提供新的解决方案。

铁载体在环境污染与资源利用中的应用研究进展

Fe在地表环境中的生物利用率极低,为了适应低铁环境,微生物和植物会分泌一种低分子量有机化合物--铁载体来螯合环境中的Fe(Ⅲ),以满足自身生命活动需求。铁载体在地表环境中普遍存在,并广泛参与微生物、植物和环境中Fe的迁移和转化。系统总结了铁载体的类型、检测方法以及其在矿物溶解、污染修复、植物促生和生物防治等领域的作用研究进展。结果表明:细菌、真菌、蓝细菌和植物均能产生不同类型铁载体,通过螯合作用从环境中摄取和竞争Fe;依据铁载体中特定的官能团,可采用生物方法和化学方法对其进行定性和定量检测;铁载体可以加速铁硅酸盐矿物和铁氧化物/氢氧化物矿物溶解,推动地表环境中不同相态Fe的生物地球化学循环;铁载体能够螯合多种重金属离子并促进有机污染物降解,修复重金属和有机物污染的土壤,维持土壤良好的生态功能和农业生产能力;铁载体还可以捕获植物所需的营养元素并抑制植物病原菌的繁殖,促进植物生长与产量提高,有效进行生物防治。最后,在综述研究的基础上展望了铁载体的未来研究方向,以期为推动铁载体在环境地学领域的研究发挥积极作用。

生物强化提高水稻糙米锌含量及其生物有效性

【目的】研究利用有机锌肥生物强化水稻糙米锌含量的可行性及其生物可给性。【方法】锌生物强化试验在江苏溧阳进行,供试锌肥为糖醇螯合态锌(Zn 170 g/L),供试水稻品种为中熟晚粳稻‘南粳46’。设5个处理:喷施清水(CK);锌肥喷施一次,用量为2.55 kg/hm^(2)(Zn1)、5.10 kg/hm^(2)(Zn2);锌肥喷施两次,总施用量为5.10 kg/hm^(2)(Zn3)、10.20 kg/hm^(2)(Zn4)。水稻成熟后,测定糙米中锌、植酸含量,测定糙米中锌赋存形态含量,计算糙米植酸/锌摩尔比、糙米锌赋存形态占比,并利用in vitro人工胃肠模拟法分析糙米锌在胃阶段和胃肠阶段的溶出量,以溶出锌与糙米锌量之比来计算糙米锌生物可给性。【结果】与CK处理相比,锌生物强化对糙米植酸含量无显著影响,但显著提高了糙米锌含量,Zn1、Zn2、Zn3和Zn4处理的增幅分别为23.93%、37.51%、82.38%和87.81%,Zn3和Zn4处理增幅差异不显著。Zn1、Zn2处理对糙米植酸/锌摩尔比无显著影响,Zn3和Zn4处理显著降低了植酸/锌摩尔比。锌处理不同程度提高了糙米中各赋存形态锌含量,Zn2处理显著提高了糙米盐溶态和碱溶态锌含量,Zn3处理显著提高了所有赋存形态锌含量,而Zn4处理显著提高了除水溶态锌外的其他3类锌含量,Zn3和Zn4处理间各赋存形态锌含量无显著差异。锌处理水平影响着糙米各赋存形态锌的占比,与CK处理相比,Zn1处理下各赋存形态锌占比无显著变化,Zn2处理显著降低了复合态锌占比,Zn3处理显著降低了水溶态锌占比,而Zn4处理显著降低了水溶态锌占比,显著提高了盐溶态锌占比。锌生物强化可提高糙米中锌在胃肠阶段的溶出量,CK、Zn1、Zn2、Zn3和Zn4处理强化后糙米锌在胃肠阶段的溶出量分别为19.52、24.15、23.14、30.62和32.55 mg/kg,Zn3和Zn4处理的溶出量无显著差异,但明显高于Zn1和Zn2处理。相关性分析表明,糙米锌在胃肠阶段溶出量与糙米锌含量极显著正相关,与糙米水溶态锌占比极显著负相关,与复合态锌占比无显著相关,糙米锌生物可给性与植酸/锌摩尔比呈极显著相关。【结论】锌生物强化可显著提高糙米总锌含量,降低植酸/锌摩尔比,提高稻米中强化锌的生物有效锌。低施锌量虽然也提升了糙米的总锌含量,但不影响糙米中各赋存形态锌的比例。高施锌量不论是一次还是分两次喷施,不仅更有效提升了糙米总锌含量,还显著降低了水溶态锌占比,增加了盐溶态锌比例,因而提高了胃肠阶段的锌溶出量。因此,以提高糙米锌含量及其生物有效性为目的的生物强化措施推荐喷施5.10 kg/hm^(2)糖醇螯合态锌肥,并分两次施用。

亚铁离子螯合肽的研究进展

铁是人体必需的微量元素,具有多种生理功能,参与人体的氧气运输且是产生血红蛋白的重要底物。缺铁导致的缺铁性贫血(IDA)可能会引起多种病症,尤其会使儿童发育和行为延迟。肽金属离子螯合物是一类新式的螯合物体系,它可以直接以无机盐形式进入到生物体内,在小肠内迅速消化吸收。作为一种新型的铁补充剂,亚铁离子螯合肽在胃肠道消化吸收利用度较高,同时还具有一定的抗氧化、抗菌等功能。通过文献研究,综述了国内外亚铁离子螯合肽的制备及性质的相关研究,以期为新型补铁原料的研究与开发提供新思路。