Visith Chavasit

Formation and characterization of an insoluble polyelectrolyte complex: chitosan-polyacrylic acid

Chitosan and polyacrylic acid mixtures were prepared in different mole ratios and at different pH values and ionic strengths (0.025–0.300). Complex formation was detected by turbidity measurement and quantified by weighing the freeze dried pellet recovered by centrifugation. No insoluble complex formation at pH=2 was detected. In the 3 to 6 pH range, the maximum complex formation occurred at different mole ratios. Quantitative analysis of the supernatant showed that pH affects the complex composition. Solution ionic strength in the 0.025–0.300 range did not affect complex formation.Supernatant pH measurement showed that in the 3 to 5 pH range, the pH of the mixture decreased as the complex was formed. At pH=6, the opposite behavior was observed. This information was used to propose a mechanism for complex formation which was confirmed by quantitative analysis of the supernatant and IR analysis of the insoluble complex. These studies showed that an electrostatic interaction between COO− and NH3+ groups was involved in complex formation.

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

Triple Fortification of Instant Noodles in Thailand

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.

Development of Fortified Dried Broken Rice as a Complementary Food

Because Thailand was facing problems with deficiencies of iodine, iron, and vitamin A, in 1994 a committee of the Ministry of Public Health proposed a feasibility study of fortification of instant noodle seasoning powder. This project was undertaken by universities, government, and the private sector. Micronutrient dosages per serving were set at 5 mg for iron, 50 μg for iodine, and 267 μg for vitamin A, all of which represent one-third of the Thai recommended daily intake (RDI). the results showed that a premix containing potassium iodide, encapsulated reduced iron, and vitamin A remained stable under accelerated storage conditions, with no adverse effects on the sensory qualities of most products. Information concerning the fortified nutrients as well as the types and brands of the fortified product was publicized through the media with support from manufacturers of instant noodles and a ministerial committee. the products were marketed at the end of 1996.

In vitro retardation of glucose diffusion with gum extracted from malva nut seeds produced in Thailand

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.

Iodine Stability and Sensory Quality of Fermented Fish and Fish Sauce Produced with the Use of Iodated Salt

Mucilage of malva nut fruit has been used as traditional medicine in Thailand. Our laboratory has succeeded in extracting malva nut gum (MNG) from malva nut seeds by using alkaline-extraction method. The extract had higher gelling properties compared to water-extracted MNG. This research was aimed to investigate the effect of MNG on the retardation of glucose diffusion in in vitro dialysis processes. The results showed that alkaline-extracted MNG significantly (p<0.05) reduced glucose content in dialysate compared to control containing no dietary fibre. MNG at 1% (w/w) concentration was more effective than that of 0.5% (w/w) concentration. The mixture of MNG and guar gum significantly (p<0.05) reduced glucose in dialysate by 50-82% compared to that of control. In starch digestion process, the mixture of MNG and guar gum showed greater reduction of glucose (3-7 folds) in dialysate at 15-30min.

Production and shelf stability of multiple-fortified quick-cooking rice as a complementary food.

Background Universal salt iodization promotes the use of iodated salt for producing industrial food products, although it might affect product quality and iodine stability. Objective To assess iodine loss during fermentation of fermented fish and fish sauces produced by using iodated salt and the effect on product sensory quality. Methods Fermented fish and fish sauces were produced with iodated rock and grain sea salts (approximately 30 ppm iodine). Fermented fish was prepared from freshwater fish mixed with salt and rice bran and fermented for 6 months at room temperature. Fish sauces were prepared by mixing anchovy with salt and fermenting either exposed to sunlight or in the shade for 12 months. Residual iodine was determined with a spectrophotometer at day 0 and months 1, 3, and 6 for fermented fish and day 0 and months 3, 6, and 12 for fish sauces. After fermentation, the products were tested for sensory acceptability by Laotian and Thai panelists (approximately 50 in each panel) after they were cooked and served in the traditional manner. Results After fermentation, the level of residual iodine was 7.61 ppm (16% loss) in fermented fish, 5.57 ppm (55% loss) in fish sauce prepared with exposure to sunlight, and 9.52 ppm (13% loss) in fish sauce prepared in the shade. Sensory qualities of the products that were produced from fortified and unfortified salts as well as dishes prepared from these products were not significantly different (p > 0.05). Conclusions It is feasible to produce fermented fish and fish sauces with iodated salt and maintain acceptable iodine levels.

Comparison of methods for iodine analysis in foods

Rice-based complementary foods normally contain inadequate amounts of several micronutrients, such as iron, calcium, and zinc. This study aimed at improving the quality of commercially produced rice-based complementary foods. The analysis centered on identifying a rice-based complementary food that is safe, stable, sensory acceptable, and economical in terms of fortificants (iron, calcium, zinc, thiamine, folate) and effectively packaged for industrial production and distribution. Product colors were mostly in green-yellow tone and slightly changed to more yellow during storage. Sensory acceptability was affected by changes in odor and rancidity but not in color. Rancidity scores were low in aluminum foil laminated plastic bags (ALU). Lipid oxidation significantly increased during storage, but at a slower rate when sodium citrate and ALU were used. Color differences of raw products were detected but not in the cooked ones. Mineral and vitamin losses during processing were 2% to 11% and 20% to 30%, respectively, but no losses were found during storage. FeSO(4)+ NaFeEDTA added with sodium citrate resulted in the most acceptable product for all packagings. The multiple-fortified quick-cooking rice (MFQCR) developed from this study could be a potentially useful tool for combating micronutrient deficiencies among infants and young children in the countries where rice is the staple food.

Effects of various iron fortificants on sensory acceptability and shelf-life stability of instant noodles.

Spectrophotometric and ICP-MS methodology for iodine determination was compared. Samples were alkali dry-ashed, dissolved in water, and iodine assayed by spectrophotometry and by ICP-MS. Iodine content in the studied foods ranged from 3 to 1304μg/100g. There was no significant difference (p>0.05) between iodine values determined spectrophotometrically using an external calibration curve and values determined using a standard addition. Foods containing low iodine concentrations (4-25μg/100g) also showed no significant difference (p>0.05) between iodine concentrations determined spectrophotometrically and concentrations determined by ICP-MS. For food items with more than 25μg/100g, the spectrophotometric methods yielded markedly higher (p<0.05) concentrations than the standard ICP-MS method (relative positive bias 25-122%), especially in foods with high sodium and/or iron contents. A catalytic effect of sodium and iron on the Sandell and Kolthoff reaction, leading to false high values in the spectrophotometric determination of iodine was demonstrated. ICP-MS is recommended for iodine determination in foods.

Recommending vitamin A-rich foods in southern Thailand.

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.