The bioaccessibility of iodine in the biofortified vegetables throughout cooking and simulated digestion.

Biofortification of crops with exogenous iodine is a novel strategy to control iodine deficiency disorders (IDD). The bioaccessibility of iodine (BI) in the biofortified vegetables in the course of soaking, cooking and digestion, were examined. Under hydroponics, the concentration of iodine in leafstalks of the celery and pakchoi increased with increasing exogenous iodine concentration, 54.8-63.9% of the iodine absorbed by pakchoi was stored in the soluble cellular substance. Being soaked in water within 8 h, the iodine loss rate of the biofortified celery was 3.5-10.4% only. More than 80% of the iodine in the biofortified celery was retained after cooking under high temperature. The highest BI of the biofortified vegetables after digestion in simulated gastric and intestinal juice amounted to 74.08 and 68.28%, respectively. Factors influencing BI included pH, digestion duration, and liquid-to-solid ratio. The high BI of the biofortified vegetables provided a sound reference for the promotion of iodine biofortification as a tool to eliminate the IDD.

Iodide and iodate effects on the growth and fruit quality of strawberry.

BACKGROUND: Iodine deficiency is an environmental health problem affecting one-third of the global population. An iodine biofortification hydroponic experiment was conducted to explore the iodide and iodate uptake characteristics of strawberry plants, to measure the dosage effects of iodine on plant growth and to evaluate the influence of I- or IO3- application on fruit quality. RESULTS: After biofortification, the iodine contents of the fresh strawberry fruits were 600-4000 µg kg-1 , covering the WHO dietary iodine allowance of 150 µg · day-1 for adults. The iodine uptake of the strawberry plants increased with increasing I- or IO3- concentration of the culture solution. At the same iodine concentration, the iodate uptakes of various plant organs under I- treatments were apparently more than those under IO3- treatments. Low-level exogenous iodine (I- ≤ 0.25 mg L-1 or IO3- ≤ 0.50 mg L-1 ) not only promoted plant growth and increased biomass per plant, but also improved fruit quality by enhancing the vitamin C and soluble sugar contents of the strawberry fruits. Nevertheless, excessive exogenous iodine inhibited plant growth and reduced biomass per plant. IO3- uptake apparently increased the total acidity and nitrate content of the fruits, reducing the quality of the strawberry fruits. Conversely, I- uptake obviously decreased the total acidity and nitrate content of the strawberry fruits, improving the fruit quality. CONCLUSION: The strawberry can be used as a target crop for iodine biofortification. Furthermore, applying an appropriate dose of KI can improve the fruit quality of the strawberry plants. © 2016 Society of Chemical Industry.

An innovative approach for iodine supplementation using iodine-rich phytogenic food.

Iodine, as one of the essential trace elements for human body, is very important for the proper function of thyroid gland. In some regions, people are still suffering from iodine deficiency disorder (IDD). How to provide an effective and cost-efficient iodine supplementation has been a public health issue for many countries. In this review, a novel iodine supplementation approach is introduced. Different from traditional iodine salt supplement, this approach innovatively uses cultivated iodine-rich phytogenic food as the supplement. These foods are cultivated using alga-based organic iodine fertilizer. The feasibility, mechanics of iodine absorption of plants from soil and the bioavailability of iodine-rich phytogenic food are further discussed.

The fate of exogenous iodine in pot soil cultivated with vegetables.

A pot experiment was conducted to explore a more effective approach to enhancing vegetable uptake of soil iodine, with the ultimate goal of using agricultural fortification as a measure to prevent iodine deficiency disorders in local communities. Two types of iodine fertilizers were added separately to pot soil samples at various dosages. The fortified soil in each of the flower pots was seeded with one of four test crops (pakchoi, celery, pepper, and radish) in an effort to examine the effect of vegetable cultivation. The fate and residual levels of the exogenous iodine in the fortified soil samples were then monitored and quantified. The data showed that the soil iodine contents decreased with time (and hence with plant growth as well). At the second cutting, iodine from the inorganic form (KI) as the exogenous source was reduced to approximately 50% (41.6-61.0%) of the applied dose, whereas that in soil fortified with the seaweed fertilizer was down to approximately 60% (53.9-71.5%). The abilities of the edible portion of the four vegetables in accumulating the soil iodine were as follows: pakchoi > celery > radish > pepper. On the whole, iodine residues were found less in soil cultivated with vegetables. Vegetable cultivation appeared to have enhanced the soil content of the water-soluble form of iodine somewhat, especially in soil fortified with the inorganic forms. There also appeared to be a significant negative correlation between the residual iodine and its dissolution rate in soil. Overall, the results of the present study pointed toward the direction that the seaweed fertilizer tends to be a (more) preferred source of agricultural fortification in promoting human iodine nutrition.

Biogeochemical transfer and dynamics of iodine in a soil-plant system.

Radioactive iodide (125I) is used as a tracer to investigate the fate and transport of iodine in soil under various leaching conditions as well as the dynamic transfer in a soil-plant (Chinese cabbage) system. Results show that both soils (the paddy soil and the sandy soil) exhibit strong retention capability, with the paddy soil being slightly stronger. Most iodine is retained by soils, especially in the top 10 cm, and the highest concentration occurs at the top most section of the soil columns. Leaching with 1-2 pore volume water does not change this pattern of vertical distributions. Early breakthrough and long tailing are two features observed in the leaching experiments. Because of the relatively low peak concentration, the early breakthrough is really not an environmental concern of contamination to groundwater. The long tailing implies that the retained iodine is undergoing slow but steady release and the soils can provide a low but stable level of mobile iodine after a short period. The enrichment factors of 125I in different plant tissues are ranked as: root > stem > petiole > leaf, and the 125I distribution in the young leaves is obviously higher than that in the old ones. The concentrations of 125I in soil and Chinese cabbage can be simulated with a dual-chamber model very well. The biogeochemical behaviors of iodine in the soil-cabbage system show that cultivating iodized cabbage is an environmentally friendly and effective technique to eliminate iodine deficiency disorders (IDD). Planting vegetables such as cabbage on the 129I-contaminated soil could be a good remediation technique worthy of consideration.

Increment of iodine content in vegetable plants by applying iodized fertilizer and the residual characteristics of iodine in soil.

As a new attempt to control iodine deficiency disorder (IDD), we explored a method of iodine supplementation by raising the iodine content in vegetables. When grown in the soil supplemented with iodized fertilizer, the three experimental plant species (cucumber, aubergine, and radish) show increasing iodine levels in both leaf and fruit/rhizome tissues as the iodine content added in soil increases. Excessive iodine added to soil can be toxic to plants, whereas the tolerance limit to excessive iodine varies in the three plant species tested. The migration and volatilization of iodine in soil is correlated with the properties of the soil used. The residual iodine in soil increases as the iodine added to soil increases. The diatomite in the iodized fertilizer helps to increase the durability of the iodized fertilizer. This study potentially provides a safe and organic iodine supplementation method to control IDD.

Uptake of different species of iodine by water spinach and its effect to growth.

A hydroponic experiment has been carried out to study the influence of iodine species [iodide (I(-)), iodate (IO(-)(3)), and iodoacetic acid (CH(2)ICOO(-))] and concentrations on iodine uptake by water spinach. Results show that low levels of iodine in the nutrient solution can effectively stimulate the growth of biomass of water spinach. When iodine levels in the nutrient solution are from 0 to 1.0 mg/l, increases in iodine levels can linearly augment iodine uptake rate by the leafy vegetables from all three species of iodine, and the uptake effects are in the following order: CH(2)ICOO(-) >I(-)>IO(-)(3). In addition, linear correlation was observed between iodine content in the roots and shoots of water spinach, and their proportion is 1:1. By uptake of I(-), vitamin C (Vit C) content in water spinach increased, whereas uptake of IO(-)(3) and CH(2)ICOO(-) decreased water spinach Vit C content. Furthermore, through uptake of I(-) and IO(-)(3). The nitrate content in water spinach was increased by different degrees.

Mechanism of iodine uptake by cabbage: effects of iodine species and where it is stored.

Iodine-enhanced vegetable has been proven to be an effective way to reduce iodine deficiency disorders in many regions. However, the knowledge about what mechanisms control plant uptake of iodine and where iodine is stored in plants is still very limited. A series of controlled experiments, including solution culture, pot planting, and field experiments were carried out to investigate the uptake mechanism of iodine in different forms. A new methodology for observing the iodine distribution within the plant tissues, based on AgI precipitation reaction and transmission electron microscope techniques, has been developed and successfully applied to Chinese cabbage. Results show that iodine uptake by Chinese cabbage was more effective when iodine was in the form of IO(3) (-) than in the form of I(-) if the concentration was low (<0.5 mg L(-1)), but the trend was opposite if iodine concentration was 0.5 mg L(-1) or higher. The uptake was more sensitive to metabolism inhibitor in lower concentration of iodine, which implies that the uptake mechanism transits from active to passive as the iodine concentration increases, especially when the iodine is in the form of IO(3) (-). The inorganic iodine fertilizer provided a quicker supply for plant uptake, but the higher level of iodine was toxic to plant growth. The organic iodine fertilizer (seaweed composite) provided a more sustainable iodine supply for plants. Most of the iodine uptake by the cabbage is intercepted and stored in the fibrins in the root while the iodine that is transported to the above-ground portion (shoots and leaves) is selectively stored in the chloroplasts.

Release of bioactive active iodine in kelp.

The release process and influencing factors of bioactive iodine of kelp are systemically studied by leaching experiment. The results showed that the bioactive iodine of kelp can be released rapidly and the principal form of iodine in lixivium is I-. There is a dynamic process between the release and absorption of iodine. With the increase of leaching water, the gross amounts of released iodine rise. There also exists a transforming process among I-, IO3- and organic iodine in lixivium.

[Determination of anilines in environmental water samples by simultaneous derivatization and ultrasound assisted emulsification microextraction combined with gas chromatography-flame ionization detectors].

This research demonstrated a new method, simultaneous derivatization and ultrasound assisted emulsification microextraction combined with gas chromatography-flame ionization detector (SD-USAEME-GC-FID), for the determination of anilines in environmental water samples. In this study, several factors, such as the volume of butylchloroformate (as derivatization agent/ extraction solvent), ultrasonication time, solution pH, salt addition, and centrifuging time and speed, were optimized in order to obtain good method performance. As a result, under the optimal conditions, the method showed good linearity in the concentration range of 6-60 000 µg x L(-1) with correlation coefficients (R2) ranging from 0.999 7 to 0.999 9 for the five target anilines. The limit of detection ( LOD) , based on signal to noise ratio of 3 , ranged from 1.1-4.1 µg x L(-1). The relative standard deviations (RSD) varied from 2.4% to 5.7% (n = 6) and the enrichment factors (EF) ranged from 317 to 846. The proposed method was also successfully applied to analyze seven environmental water samples, with the relative recoveries (RR) ranging from 86.8% to 105.5%. In a conclusion, this method was convenient, highly sensitive, inexpensive and environment-friendly, and therefore, the present method can be used as a preferred method for the determination of anilines in environmental water samples.

Remove volatile organic compounds (VOCs) with membrane separation techniques.

Membrane separation, a new technology for removing VOCs including pervaporation, vapor permeation, membrane contactor, and membrane bioreactor was presented. Comparing with traditional techniques, these special techniques are an efficient and energy-saving technology. Vapor permeation can be applied to recovery of organic solvents from exhaust streams. Membrane contactor could be used for removing or recovering VOCs from air or wastewater. Pervaporation and vapor permeation are viable methods for removing VOCs from wastewater to yield a VOC concentrate which could either be destroyed by conventional means, or be recycled for reuse.

Capacity and degree of iodine absorbed and enriched by vegetable from soil.

To understand the biogeochemical transfer of iodine, the absorbability and bioaccumulation of iodine in tested vegetables (radish, spinach and Chinese cabbage) are examined by applying iodic fertilizer composed of kelp and diatomaceous earth. The experimental results show that when iodine in soil is not excessive, the concentrations of iodine in tested vegetables increase as the content of iodine in soil increases. The absorbability and enrichment degree of iodine in various vegetables and in various parts of the same vegetable a redifferent, which explains that the concentration of iodine in plant is determined by the plant type and the physiological action of plant. The patience order of tested vegetables to excessive iodine is Chinese cabbage > spinach > radish. These results have theoretical and practical significance in opening up a new way for ameliorating poor iodine environment with artificial means.

Transformation of heavy metal speciation during sludge drying: mechanistic insights.

Speciation can fundamentally affect on the stability and toxicity of heavy metals in sludge from wastewater treatment plants. This research investigated the speciation of heavy metals in sludge from both municipal and industrial sources, and metal speciation change as a result of drying process to reduce sludge volume. The changes in sludge properties including sludge moisture content, temperature, density, and electrical conductivity were also monitored to provide insights into the mechanisms causing the change in heavy metal speciation. The results show that the drying process generally stabilized Cr, Cu, Cd, and Pb in sludge by transforming acid-soluble, reducible, and oxidizable species into structurally stable forms. Such transformation and stabilization occurred regardless of the sludge source and type, and were primarily caused by the changes in sludge properties associated with decomposition of organic matter and sulfide. The results enhanced our understanding of the geochemical behavior of heavy metals in municipal sludge, and are useful for designing a treatment system for environment-friendly disposal of sludge.

[Drying characteristics and apparent change of sludge granules during drying].

Three different weight grades of sludge granules (2.5, 5, 10 g) were dried at constant temperature of 100, 200, 300, 400 and 500 degrees C, respectively. Then characteristics of weight loss and change of apparent form during sludge drying were analyzed. Results showed that there were three stages during sludge drying at 100-200 degrees C: acceleration phase, constant-rate phase, and falling-rate phase. At 300-500 degrees C, there were no constant-rate phase, but due to lots of cracks generated at sludge surface, average drying rates were still high. There was a quadratic nonlinear relationship between average drying rate and drying temperature. At 100-200 degrees C, drying processes of different weight grade sludge granules were similar. At 300-500 degrees C, drying processes of same weight grade of sludge granules were similar. Little organic matter decomposed till sludge burning at 100-300 degrees C, while some organic matter began to decompose at the beginning of sludge drying at 400-500 degrees C.

[Characteristics of iodine uptake and accumulation by vegetables].

With seaweed iodine and KI as exogenous iodine sources, a pot experiment was conducted to study the characteristics of iodine uptake and accumulation by pakchoi cabbage, celery, capsicum, and radish. The results showed that the iodine content in the edible parts of test vegetables increased with increasing amount of exogenous iodine, but the iodine accumulation rate differed with the kinds of vegetables, in the order of pakchoi > celery > radish > capsicum. The majority of iodine was accumulated in roots, with lesser amount transferred to shoots. The distribution of iodine in vegetables was commonly in the order of root > leaf > stem > fruit, but the iodine in radish is lower in its rhizome than in its shoot. Low concentrations (0-25 mg x kg(-1)) of exogenous iodine had little effects on the growth of vegetables, while high concentrations (> or = 50 mg x kg(-1)) of it had inhibitory effects, resulting in a decreased vegetable biomass. The sensitivity of test vegetables to the adverse effect of exogenous iodine was in the order of capsicum > pachoi > celery > radish. Compared with seaweed iodine, KI decreased the biomass of first cutting significantly (P < 0.05), but for the second cutting, little difference was observed between these two iodine sources. The uptake and accumulation of these two iodine sources by vegetables also differed with cuttings, i.e., the first cutting vegetables absorbed more KI, while the second cutting vegetables absorbed more seaweed iodine (P < 0.05), suggesting that seaweed iodine had a longer efficacy than KI.