Forward screening for seedling tolerance to Fe toxicity reveals a polymorphic mutation in ferric chelate reductase in rice

BACKGROUND

Rice contains the lowest grain Fe content among cereals. One biological limiting factor is the tolerance of rice to Fe toxicity. Reverse and forward genetic screenings were used to identify tolerance to Fe toxicity in 4,500 M4 lines irradiated by fast neutrons (FN).

FINDINGS

Fe-tolerant mutants were successfully isolated. In the forward screen, we selected five highly tolerant and four highly intolerant mutants based on the response of seedlings to 300 ppm Fe. Reverse screening based on the polymorphic coding sequence of seven Fe homeostatic genes detected by denaturing high performance liquid chromatography (dHPLC) revealed MuFRO1, a mutant for OsFRO1 (LOC_Os04g36720). The MuFRO1 mutant tolerated Fe toxicity in the vegetative stage and had 21-30% more grain Fe content than its wild type. All five highly Fe-tolerant mutants have the same haplotype as the MuFRO1, confirming the important role of OsFRO1 in Fe homeostasis in rice.

CONCLUSIONS

FN radiation generated extreme Fe-tolerant mutants capable of tolerating different levels of Fe toxicity in the lowland rice environment. Mutants from both reverse and forward screens suggested a role for OsFRO1 in seedling tolerance to Fe toxicity. The MuFRO1 mutant could facilitate rice production in the high-Fe soil found in Southeast Asia.

Nutrients value and antioxidant content of indigenous vegetables from Southern Thailand

Evidence from epidemiological studies has strongly suggested that diets rich in fruits and vegetables play a vital role in disease prevention. The aim of this study was to determine nutrient and antioxidant content for 15 varieties of indigenous vegetables and fruits collected from Southern Thailand. The data indicated that indigenous vegetables provided small to moderate amounts of macronutrients and minerals. The highest content of β-carotene was found in Indian lettuce (Lactuca indica; 3575.54 μg/100 g), whereas water dropwort (Oenanthe javanica; 7439.11 μg/100 g) had the highest lutein content. Ripe cashew apple (Anacardium occidentale; 178.34 mg/100 g) and Spanish joint fir (Gnetum gnemon; 109.43 mg/100 g) were excellent sources of vitamin C. Mon-pu (Glochidion perakense) and young cashew leaves (Anacardium occidentale) were rich sources of β-carotene, lutein, total polyphenol, especially gallic acid, and had relatively high ORAC and FRAP activities. In conclusion, Thai indigenous vegetables provide diverse natural bioactive compounds that may contribute health benefits to the consumer.

Protective effects of coenzyme q(10) on decreased oxidative stress resistance induced by simvastatin

The effects of simvastatin, an inhibitor of 3-hydroxy-3-methylglutaryl CoA reductase (HMG-CoA reductase), on oxidative stress resistance and the protective effects of coenzyme Q (CoQ) were investigated. When simvastatin was administered orally to mice, the levels of oxidized and reduced CoQ₉ and CoQ₁₀ in serum, liver, and heart, decreased significantly when compared to those of control. The levels of thiobarbituric acid reactive substances induced by Fe²⁺-ascorbate in liver and heart mitochondria also increased significantly with simvastatin. Furthermore, cultured cardiac myocytes treated with simvastatin exhibited less resistance to oxidative stress, decreased time to the cessation of spontaneous beating in response to H₂O₂ addition, and decreased responsiveness to electrical field stimulation. These results suggested that oral administration of simvastatin suppresses the biosynthesis of CoQ, which shares the same biosynthesis pathway as cholesterol up to farnesyl pyrophosphate, thus compromising the physiological function of reduced CoQ, which possesses antioxidant activity. However, these undesirable effects induced by simvastatin were alleviated by coadministering CoQ₁₀ with simvastatin to mice. Simvastatin also reduced the activity of NADPH-CoQ reductase, a biological enzyme that converts oxidized CoQ to the corresponding reduced CoQ, while CoQ₁₀ administration improved it. These findings may also support the efficacy of coadministering CoQ₁₀ with statins.

Shelf Stability, Sensory Qualities, and Bioavailability of Iron-Fortified Nepalese Curry Powder

Background

The prevalence of iron-deficiency anemia in Nepal is almost 50% of the whole population. Curry powder is a promising vehicle for fortification due to its use in various meals.

Objective

To evaluate the bioavailability of different iron fortificants in curry powder and their effects on the qualities of curry powder.

Methods

The serving size of curry powder was evaluated in 40 Nepalese households and 10 restaurants. The powders were fortified with iron sources of different bioavailability. Sources with good bioavailability of iron—ferrous sulfate (FS), ferrous fumarate (FF), and sodium ferric ethylenediaminetetraacetic acid (NaFeEDTA)—were added to provide one-third of the recommended daily intake (RDI) of iron per serving. Elemental iron (H-reduced [HRI] and electrolytic [EEI]), which has poor bioavailability, was added to provide two-thirds of the RDI per serving. Both fortified and unfortified products were packed in either commercial packs or low-density polyethylene bags and stored at 40 ± 2°C under fluorescent light for 3 months. The stored products were analyzed for CIE color, peroxide value, thiobarbituric acid reactive substances, moisture, water activity, iron, and sensory qualities. The contents of phenolic compounds and phytate were analyzed, and iron bioavailability was determined by the Caco-2 cell technique.

Results

The serving size of curry powder was 4g. Iron fortificants did not have adverse effects on the physical, chemical, and sensory qualities of curry powder packed in commercial packaging. After 3 months storage, HRI significantly affected darker colors of curry powder and the cooked dishes prepared with curry powder. The relative bioavailabilities of NaFeEDTA and EEI were 1.05 and 1.28 times that of FS, respectively. The cost of fortification with EEI was similar to that with FS and 4.6 times less than that with NaFeEDTA.

Conclusions

It is feasible and economical to fortify Nepalese curry powder packed in commercial packaging with EEI.

Cadmium bioavailability from vegetable and animal-based foods assessed with in vitro digestion/caco-2 cell model

BACKGROUND

Chronic dietary cadmium (Cd) exposure results in kidney dysfunction and decrease in bone mineral density.

OBJECTIVE

To determine and compare the bioavailability of Cd from vegetable and animal-based foods.

MATERIAL AND METHOD

Caco-2 cells were exposed to Cd in boiled pig kidney, ark shell, kale, raw kale, mixed boiled pig kidney with raw kale and CdCl2 after in vitro digestion. Then cellular Cd uptake from the digests and reference CdCl2 solution was measured by atomic absorption spectrometry.

RESULTS

Cd bioavailability from animal-based foods was higher than that from vegetable-based foods. In addition, raw kale exhibited an inhibitory effect on Cd bioavailability when mixed with boiled pig kidney. However Cd in kale was increasingly absorbed after boiling.

CONCLUSION

Cd binding to different molecular species, other food components in vegetable and animal-based foods, food combination, as well as cooking processes influenced the uptake of dietary Cd. A relative bioavailability factor accounted for the food matrix might be necessary for exposure assessment and consequently for estimation and prevention of the risk of dietary Cd.

Effects of Various Iron Fortificants on Sensory Acceptability and Shelf-Life Stability of Instant Noodles

Background

Iron-deficiency anemia is the most common nutritional problem in Thailand and many developing countries. One of the most sustainable and cost-effective strategies for combating iron deficiency is fortification of staple foods with iron.

Objective

In this study, the feasibility of fortifying instant noodles with different forms of iron fortificants (ferrous sulfate [FS], ferric sodium ethylenediamine- tetraacetic acid [NaFeEDTA], and encapsulated H- reduced elemental iron [EEI] was evaluated, and the fortified noodles were compared with unfortified noodles for changes in physical, chemical, and sensory qualities.

Methods

Wheat flour used to make instant noodles was fortified to produce a concentration of 5 mg of iron per 50-g serving of instant noodles (one-third of the Thai recommended dietary intake).

Results

Analytical data showed that the iron contents were close to 5 mg per serving of noodles fortified with FS, NaFeEDTA, or EEI (5.27 ± 0.10, 4.27 ± 0.07, and 5.26 ± 0.47 mg, respectively). The color quality (measured by L*, lightness, and b*, yellowness) of the raw dough sheet and of uncooked and cooked instant noodles fortified with FS was lower than that of the unfortified, but color quality was not changed by the addition of NaFeEDTA. The overall sensory acceptability scores of unfortified and fortified noodles were about 6 (“like slightly”). No metallic odor was observed. During 3 months of storage at room temperature, the iron fortificants did not affect the peroxide level, color, or sensory qualities of the product.

Conclusions

Iron fortification of wheat flour used to make instant noodles is feasible. NaFeEDTA is the preferred fortificant because of its nonsignificant effect on the color and sensory quality of the products.

Fortification of Soy Sauce Using Various Iron Sources: Sensory Acceptability and Shelf Stability

Background

Soy sauces are available in different types and grades, which allows them to reach consumers of all socioeconomic groups. Ferric sodium ethylenediaminetetraacetic acid (NaFeEDTA) has been used for iron fortification of soy sauces in some countries, however, its high cost may make it unattractive to policymakers and industry.

Objective

We evaluated the feasibility of using more economical iron sources for iron fortification, with soy sauce of various types and grades used as a vehicle.

Methods

Seven iron sources were tested for their feasibility for fortification of four types of soy sauce: naturally fermented in the traditional style, naturally fermented according to large-scale industrial formulas 1 and 5, and chemically hydrolyzed at 5 mg per serving (15 mL, per Thailand's food labeling regulations). Either citric acid or sodium citrate was added at 0.1% as a chelator.

Results

Five iron sources—ferrous sulfate, NaFeEDTA, ferric ammonium citrate, ferrous lactate, and ferrous gluconate—did not significantly affect the sensory qualities of the product over a period of 3 months ( p > .05). Ferrous fumarate and ferrous bisglycinate caused unacceptable precipitation. Less than 3% of 260 and 306 commonly cooked foods out of 871 and 772 preparations using soy sauces fortified with NaFeEDTA and ferrous sulfate, respectively, were found to be different from normal with regard to sensory qualities. The cost of fortification was US 0.22 cents to US 3.28 cents per bottle (700 mL).

Conclusions

Both naturally fermented and chemically hydrolyzed soy sauces could be fortified with all five iron sources. Ferrous sulfate is the most appropriate source because of its low cost and acceptable sensory characteristics. Soy sauce is a promising vehicle for iron fortification, however, the bioavailability of iron in the products examined here needs to be evaluated under normal use conditions.

Development of Fortified Dried Broken Rice as a Complementary Food

Background

Commercially produced dried broken rice is widely used to prepare complementary foods for Thai infants, and it is both convenient and acceptable to persons from all socioeconomic classes. However, inadequate levels of calcium, iron, thiamine, and folate are common in complementary foods for breastfed infants.

Objective

We developed dried broken rice fortified with these nutrients at levels recommended by the 2001 guidelines of the World Health Organization.

Methods

The fortification process involved predrying broken rice at 90°C for 1 hour, soaking in a nutrient solution (2:1 ratio of rice to solution), and drying at 70°C for 1 hour and 50 minutes. Calcium lactate or calcium lactate gluconate was the calcium source, and ferrous sulfate, ferrous lactate, or ferric sodium ethylenediaminetetraacetic acid (NaFeEDTA) was the iron source. The vitamin sources were thiamine hydrochloride and folic acid. The product contained 40 mg of calcium, 5.3 mg of iron, 0.08 mg of thiamine, and 11 μg of folate per 20-g serving.

Results

Approximately 5% and 10% of calcium and iron, respectively, were lost during processing, with a thiamine loss of approximately 13%, and a folate loss ranging from 17% to 23%. The thiamine loss during accelerated storage (42°C for three months) was not significant ( p > .05).

Conclusions

NaFeEDTA was the most appropriate iron fortificant because it provided prolonged product stability and high in vitro dialyzability.

Combating iodine and iron deficiencies through the double fortification of fish sauce, mixed fish sauce, and salt brine

Two iodine and seven iron compounds were tested for use in the fortification of pure fish sauce, mixed fish sauce, and salt brine for cooking as a means to combat iodine and iron deficiencies. Ferrous sulfate, sodium iron ethylenediaminetetraacetic acid, ferric ammonium citrate, and ferrous lactate were combined with potassium iodide with no effect on sensory quality. Product shelf-life testing revealed that no iron or iodine losses occurred during a three-month storage period. Although the color of most products darkened, the color was not significantly different from that of nonfortified products after two to three months. Sensory home-use tests revealed that the fortified products were acceptable to highly acceptable, with only 1.2% to 8.2% of the dishes cooked using the fortified products being reported as discolored. The cost of fortification was minimal, at 0.13 to 2.73 baht per bottle (750 ml) (42 baht = US$1). Consequently, these products show a potential for inclusion in national programs for the prevention of micronutrient deficiencies in Asian countries where fish sauce and its products are routinely consumed.