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Developing a Commercial Process for Tortilla Fortification (Nutriview, 2008/2) This article summarizes a successful initiative undertaken by SUSTAIN and public and private sector partners to develop a fortification system for Mexico’s ubiquitous small tortilla millers. Corn tortillas, the traditional staple food for many Mexicans, are deficient in several key micronutrients critical to health and well being. Fresh lime-steeped corn (nixtamal) is rolled and baked into tortillas and other products in small neighborhood mills throughout Mexico on a daily basis. Nixtamal is also dried to produce corn masa flour, which is rehydrated for use in tortilla production. These two manufacturing methods each account for roughly half of the commercial tortilla market in Mexico (although estimates of market shares vary). Until recently only the flour, not the fresh nixtamal dough, could be successfully fortified with essential micronutrients. The innovative system described here cost effectively enriches nixtamal dough, resulting in nutritionally superior products fully acceptable to consumers. Effect of Iron Source on Color and Appearance of Micronutrient-Fortified Corn Flour Tortillas (Cereal Chemistry, Volume 85, Number 4, 2008) This publication, the “Editor’s Pick” in the September issue of Cereal Chemistry, evaluated the effect of different iron sources on instrumental color values and sensory color perception in fortified corn tortillas. Corn masa flour was fortified with micronutrient premix containing vitamins, zinc, and one of eight iron compounds. All iron-fortified tortillas were significantly darker than control tortillas. A-131 electrolytic iron is recommended for fortification of corn tortillas due to minimal effect on color and significantly lower cost than other iron sources evaluated. A New Tool to Evaluate Iron Bioavailability (Nutriview, 2008/3) Fortification planners would ideally like to enrich foods with iron products most likely to effectively alleviate iron deficiency, which affects an estimated 50% of children, 42% of women and 26% of men in developing countries. Elemental iron powders are most often utilized due to their relatively low cost and lack of undesirable interactions with food vehicles. Clearly it would be useful to identify which of these products are likey to be the best performers without resorting to costly biological or human efficacy studies. This article describes a new tool developed by SUSTAIN and its partners to rank widely used iron fortificants and identify those most likely to improve the iron status of iron deficient populations. The simple in vitro screening procedure, based on rates of dissolution in dilute hydrochloric acid, accurately and reliably predicts the potential efficacy of iron products (how well different iron forms are likely to be absorbed from foods during digestion). It can be used by industry to initially screen new products (and decide which merit further evaluation in human trials), and as a quality control tool to periodically evaluate product batches in manufacturing. Its use can also support innovation to improve product performance. Use of the method could help fuel a move away from static government requirements on fortification levels that do not factor in bioavailability. Steps in the development of the tool and SUSTAIN’s plans to have it validated by an international standards body are described. Effect of Micronutrient Fortification on Nutritional and Other Properties of Nixtamal Tortillas (Cereal Chemistry, Volume 85, Number 1, 2008) This report presents the results of laboratory research constituting phase one of SUSTAIN’s tortilla fortification initiative. Objectives were to compare nutritional and other attributes of micronutrient fortified vs. control tortillas made from fresh nixtamalized corn (corn steeped in hot water and lime, subsequently washed and formed into dough). Nixtamal was fortified with iron, zinc, folic acid, niacin, riboflavin, and thiamin. Premix composition followed a proposed Mexican regulation for corn flour fortification, adjusted for moisture. Effects of premix on masa adhesiveness, hardness, and pH, as well as tortilla sensory properties, stretchability, rollability, and color were measured. Micronutrient levels were tested in the dry corn, nixtamal, masa, and tortillas. There were no significant differences in masa texture or pH, tortilla rollability, or consumer acceptance of tortillas when comparing unfortified control and fortified treatments. Despite some processing losses, fortification resulted in significant nutrient increases compared with control tortillas. Folic acid increased 974%, riboflavin increased 300%, niacin increased 141%, iron increased 156%, and zinc increased 153% in fortified tortillas. Conclusions suggest that fortification of nixtamal tortillas could significantly reduce micronutrient deficiencies in target populations. Industrial Approaches to Micronutrient Fortification of Traditional Nixtamal Tortillas (Cereal Foods World, September/October 2007) This Cereal Foods World feature recounts the pioneering development of technology for enriching tortillas made from lime-steeped corn (nixtamal) in the small mill environments of Mexico. The dough (masa) is fortified with a dry premix containing iron, zinc, thiamin, riboflavin, niacin and folic acid. The dosification system is readily adaptable to most conventional mills, yields products with consistent and significant nutrient increases compared to unfortified tortillas, and can be installed and operated at minimal cost. Extended commercial trials are underway in different parts of Mexico where deficiencies in key micronutrients constitute a severe public health problem. The initiative was undertaken by SUSTAIN in partnership with Brigham Young University and the Center for Research in Nutrition and Health of the National Institute of Public Health of México (INSP), and in consultation with scientists and industrialists from Salvador Zubiran National Institute of Medical Sciences & Nutrition (INCMNSZ), Consejo Empresarial del Maiz y sus Derivados (an association of nixtamal and tortilla producers in Mexico and neighboring states), Monterrey Institute of Technology and Higher Education (ITESM), and specialists representing the micronutrient premix and tortilla milling sector. A Comparison of Physical Properties, Screening Procedures and a Human Efficacy Trial for Predicting the Bioavailability of Commercial Elemental Iron Powders Used for Food Fortification (International Journal for Vitamin and Nutrition Research, Vol. 77 No. 2, 2007) This SUSTAIN Task Force Report presents conclusions and recommendations from a broad research initiative to evaluate the potential efficacy of all commercial iron powders used as food fortificants, and the potential utility of available bioavailability screening methods. The Elemental Iron Studies Project included characterization of physical properties (particle size, surface area, density and Fisher subsieve size), dissolution rate, AOAC rat hemoglobin repletion, dialyzability, Caco-2 cell iron uptake, and plasma iron tolerance in human volunteers. After the studies on each of these screening methods were completed, a human efficacy study was conducted with selected powders. Important differences were found among existing commercial iron powders (determined to a large extent by method of manufacture) that are likely to impact bioavailability. Some, but not all, of the carbonyl and electrolytic powders had the highest predicted bioavailability values, although still less than that of ferrous sulfate. The predicted bioavailability of reduced iron products was variable and too low for them to be efficacious. However preliminary evaluation of a new experimental reduced iron powder developed by one industry partner during the course of the study suggests that it is possible to manufacture commercial reduced iron products with adequate bioavailability. The dissolution rate of pure powders appears to be the best single screening method when evaluated against the standard of the AOAC rat hemoglobin repletion method, showing good replicate reproducibility for all powders tested. Dissolution test data is also in agreement with the results of a human efficacy study of women with low iron stores in Thailand. Reprinted with permission from the International Journal of Vitamin and Nutrition Research. Fortifying Food (The International Journal of Powder Metallurgy, Vol. 38 No. 5, 2002) In this report, SUSTAIN apprises industry of its research program to evaluate the efficacy of elemental iron powder food fortificants. Powders were first evaluated in a series of in vitro and biological screening studies. Human trials with mildly iron deficient human volunteers were also undertaken. This document includes background information on SUSTAIN, its projects, and vitamin and mineral enrichments of flour and cereal foods. Reprinted with permission from the International Journal of Powder Metallurgy, 2002, Vol 38, No. 5, p. 20, a publication of APMI International, 105 College Road East, Princeton, NJ 08549-6692, USA. Enhancing the Absorption of Fortification Iron: A SUSTAIN Task Force Report (International Journal for Vitamin and Nutrition Research, Vol. 74 No. 6, November 2004) This document is the overview paper that introduces SUSTAIN’s full Task Force Report in a special issue of the International Journal for Vitamin and Nutrition Research titled “Innovative Ingredient Technologies to Enhance Iron Absorption.” The full report presents the findings of a SUSTAIN Task Force of nutritional, medical, industry and government experts, set up to consider innovative approaches to addressing iron deficiency through food fortification combined with strategies for enhancing the absorption of fortification iron. It consists of the overview paper followed by five scientific papers each focusing in depth on a specific enhancement strategy, and a cost analysis. The bioavailability of iron fortificants can be enhanced with ascorbic acid, NaFeEDTA, ferrous bisglycinate, and dephytinization all of which, however, add to the overall costs of fortification. Encapsulation of iron salts in lipid coatings, while not an iron absorption-enhancing strategy per se, can prevent soluble forms of iron from interacting undesirably with some food vehicles and hence broaden the application of some fortificants. The overview paper accessible here summarizes the current scientific knowledge about these strategies and technologies and presents consensus points on the appropriate uses, limitations, and costs of each. Task force consensus points were based on discussions at a March 2003 workshop in Washington, DC as well as on extensive subsequent consultation. While all iron enhancing strategies cannot be recommended for all food fortification vehicles, individual strategies can be recommended for specific foods. For example, the addition of ascorbic acid is appropriate for dry blended foods such as infant foods and other dry products made for reconstitution that are packaged, stored and prepared in a way that maximizes retention of this vitamin. NaFeEDTA can be recommended for fortification of fish sauce and soy sauce, whereas amino acid chelates may be more useful in milk products and beverages. With further development, dephytinization may be possible for low cost cereal-based complementary foods in developing countries. For access to the overview paper, please use the link above. Reprinted with permission from the International Journal of Vitamin and Nutrition Research. For the full task force report, please go to http://verlag.hanshuber.com/IJVNR. Increasing Bioavailability of Iron-Fortified Foods (Food Technology, August 2005) Enhancing Iron Fortification (World Grain, April 2005) Enhancing Absorption of Iron from Fortified Foods (Nutriview, 2005/1) These three articles each present a summary of the main recommendations from SUSTAIN’s Task Force Report on the appropriate uses, limitations and costs of different iron enhancing technologies. This information is thus made available to an international audience of food scientists, nutritionists, trade and industry representatives and public health stakeholders. The Nutriview article contains a detailed table outlining the suitability, effect, limitations and relative cost of each of the iron enhancing technologies reviewed by the Task Force. Increasing Bioavailability of Iron-Fortified Foods reprinted with permission from Food Technology. To read this article, please click on the link above. To read World Grain magazine's coverage of SUSTAIN's iron enhancing fortification efforts, use the link above to access the article, Enhancing Iron Fortification. To read the Nutriview article, please use the link above. Iron bioavailability from iron-fortified Guatemalan meals based on corn tortillas and black bean paste (AJCN Vol 75, 2002) This paper reports the results of an iron bioavailability trial using ferrous sulfate, ferrous fumerate (with and without the addition of Na2EDTA) and NaFeEDTA in healthy adolescent Guatemalan schoolgirls with limited storage iron. In this trial, girls were fed typical Guatemalan meals based on black bean paste and corn tortillas made from corn masa flour (cmf) fortified with one of the three isotopically labeled iron fortificants. Results showed similar iron bioavailability (approximately 6%) from tortillas fortified with ferrous sulfate and ferrous fumerate (without the Na2EDTA enhancer). Adding Na2EDTA to ferrous fumerate did not improve bioavailability. NaFeEDTA was significantly more bioavailable from the meal (9%). These results suggest that Na2EDTA is not an alternative to ascorbic acid as an enhancer of iron absorption for iron compounds that are less soluble than ferrous sulfate, and provide further support for the use of NaFeEDTA in cereal flour fortification when the sensory quality of the food is not affected. To read the American Journal of Clinical Nutrition article, please use the link above. Usage Report of “Guidelines for Iron Fortification of Cereal Food Staples” (April 2002) After publishing its guidelines, SUSTAIN conducted a limited survey with respondents from public and private sectors working on five continents. The responses indicated that the interim Iron Guidelines had been broadly disseminated and were being widely used a year later. This report summarizes feedback from this survey. Iron Guidelines Widely Used (Nutriview, 2002/3) Reports on SUSTAIN’s April 2002 survey which revealed worldwide usage of its “Guidelines for Iron Fortification of Cereal Food Staples”, and announces the launch of SUSTAIN’s comprehensive bioavailability evaluation of iron powder fortificants. To read this Nutriview article, please use the link above. Guidelines for Iron Fortification of Cereal Food Staples (May 2001) Following a September 2000 workshop in Monterrey, Mexico on iron powder bioavailability, SUSTAIN issued recommended guidelines for the type and levels of iron to add to cereal food staples, with the goal of optimizing bioavailability, cost-effectiveness, and consumer acceptance of the fortified product. The Guidelines have been reviewed and endorsed by leading experts in the field, but should be considered interim for they may change as more information becomes available. Guidelines for Iron Fortification of Cereal Food Staples (Nutriview, 2001/3) Presents the main recommendations from SUSTAIN’s interim guidelines including criteria for the selection of an iron fortificant, factors for determining appropriate addition levels and a proposed investigation of the elemental iron powders widely used in food fortification. To read this Nutriview article, please use the link above. Summary of Monterrey Workshop: Evaluating the Usefulness of Elemental Iron Powders (September 2000) To help resolve questions about the efficacy of elemental iron powders—the most commonly used iron fortificants worldwide--SUSTAIN convened a panel of world-renowned research, nutrition, and industry specialists in Monterrey Mexico (September 2000) to review and evaluate conflicting reports in the literature (from 5% to 145% relative bioavailability). Participants concluded that past research generally could not be applied to the products now commercially available, and recommended a rigorous new study of these products. This document summarizes key findings from the workshop and interim recommendations for the use of elemental iron fortificants. Monterrey Workshop Summary: Evaluating the Usefulness of Elemental Iron Powders (Nutrition Reviews, July 2002) A summary of the Monterrey Workshop” appears in Nutrition Reviews, July 2002, Vol 60, No 7. To read this Nutrition Reviews article, please use the link above. The Usefulness of Elemental Iron for Cereal Flour Fortification: A SUSTAIN Task Force Report (Nutrition Reviews, December 2002) This lead article is based on an extensive literature review and on discussions issuing from the September 2000 Monterrey Workshop on the bioavailability of elemental iron powders. Despite the magnitude of iron deficiency as a global public health problem, little is known about the extent to which elemental iron fortificants are absorbed by the body. This paper reviews research conducted over the past 45 years, discusses problems and limitations of past studies and summarizes interim recommendations on the use of elemental iron fortificants based on best available knowledge. Following its publication, SUSTAIN launched a major new research initiative to rigorously assess the efficacy of each of the iron powders commercially available today. To read this publication in Nutrition Reviews, please use the link above. The Promise and Challenge of Corn Masa Flour Fortification (World Grain, February 2003; Spanish version appeared in World Grain, October 2002) This publication is intended to raise awareness in industry and government of corn masa flour (CMF) as a potential food vehicle for fortificant iron. CMF is widely used to make tortillas, a staple of Latin diets. An extensive literature review is summarized and information presented from considerable primary research on CMF production and consumption trends in Mexico and Central America. SUSTAIN synthesizes state of the art knowledge about iron deficiency, addresses the challenges of fortifying staple foods with iron and reviews government and industry efforts to establish standards and protocols for CMF fortification. SUSTAIN also describes how these and other fortification initiatives have been hindered by inadequate knowledge about how well various iron fortificants are absorbed and how they react with food vehicles. To read World Grain magazine’s coverage of SUSTAIN’s maize flour fortification efforts, use the links above to access the article, “The Promise and Challenge of Corn Masa Flour Fortification.” Fortification of Corn Masa Flour with Iron and/or Other Nutrients: A Literature and Industry Experience Review (December 1997) Tortillas are a major food staple in Central American countries, particularly in rural populations. Corn masa flour (CMF), a timesaving alternative to the labor-intensive process of making tortilla dough from raw ingredients, provides a convenient vehicle for enrichment. This document provides a thorough review of literature and industry experience with CMF fortification, revealing that our current knowledge and technology for this is very limited. Recommendations are made for quality and bioavailability studies of CMF tortillas and other CMF products fortified with selected iron compounds. Storage, Sensory and Bioavailability Evaluation of Iron Fortified Corn Masa Flour: SUSTAIN Final Report (August 2000) Iron fortification of corn masa flour (CMF) offers an opportunity to improve the nutritional status of millions of iron deficient consumers who use the product to make tortillas in Mexico and Central America. This report presents findings from a three-part study that SUSTAIN commissioned in 1998 to identify an iron fortificant appropriate for use in corn masa flour, e.g., one that does not adversely affect the product, and that is readily absorbed by the body. Ferrous fumarate, though it is not optimal in all respects, emerges as the most promising iron compound for CMF fortification based on the combined results of storage, sensory and bioavailability tests. |
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