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1.
《Cereal Chemistry》2017,94(6):917-921
Neural tube defects occur at higher rates in Hispanic populations in the United States. Such populations would benefit from folic acid fortification of corn masa flour (CMF). This study evaluated folate stability in fortified CMFs and tortillas and tortilla chips made therefrom. There was no significant loss of folate during the six‐month shelf life of fortified tortilla CMF and tortilla chip CMF. There was a 13% loss (P < 0.05) of folate during tortilla baking and no loss during tortilla chip frying. Both tortillas and tortilla chips showed significant folate losses over the two‐month shelf life for these products, with a 17% loss in fortified tortillas and a 9% loss in tortilla chips. Folate in fortified CMFs, tortillas, and tortilla chips is relatively stable and comparable to the stability of folate in wheat flour and breads.  相似文献   

2.
A pressurized liquid extraction (PLE) method using phosphate buffer as solvent was applied for folic acid (FA) extraction from fortified wheat flours and was compared to a standard solid-liquid extraction (SLE) method. Extracted FA was quantified by reverse phase high-performance liquid chromatography (RP-HPLC) hyphenated with a phenyl column and an absorption photometric detector (λ = 280 nm). Detection and quantification limits were 0.12 and 0.4 ng, respectively, corresponding to 0.06 and 0.2 μg g(-1) of analyzed wheat flour. Equivalent FA contents were found by both extraction methods, but a single PLE allowed a total recovery of FA content, whereas at least three successive SLEs were needed to achieve a total recovery of FA. The obtained results indicated that PLE is a rapid and efficient technique for FA extraction from fortified wheat flour.  相似文献   

3.
Many Mexican women are deficient in folic acid. Fortification of the corn tortilla could be an effective way to help increase the folic acid levels among the Mexican population. Previous studies have shown significant folic acid losses in the masa dough as it is held before baking. This loss in folic acid could be owing to utilization by lactic acid bacteria naturally present in the masa. The objective of this study was to determine the effect of bacteria native to corn masa on the folic acid content in masa. Bacteria in dough samples from six mills in Guadalajara, Mexico, were isolated and identified. Bacterial isolates were inoculated into sterile fortified corn masa flour, which was converted to masa and held at 56°C for 0, 3, and 6 h, replicating the conditions of freshly milled masa as held before baking. All samples, including the control, showed losses of folic acid between 66 and 79% w/w in the first 3 h of incubation. Because folic acid degradation in the sterile control sample was not different than the inoculated sample results, the decline in folic acid was not owing to bacteria (mainly Streptococcus spp.) present in the masa flour but appeared to be a chemical degradation related to time and temperature.  相似文献   

4.
In 2002, Brazil issued a regulation requiring that corn and wheat flours be fortified by the addition of folic acid and iron. The aim of the present work was to evaluate the levels of folic acid, iron, and zinc in macaroni, pizza, and bread prepared with fortified flour. The methodologies used for the mineral (FAAS) and vitamin (HPLC) determinations were validated and considered adequate. For macaroni, the folic acid content range was 50.0–182.4 μg/100 g. The iron and zinc levels were 1.6–5.4 mg/100 g and 0.7–1.0 mg/100 g, respectively. The pizza and bread samples contained 14.8–271.3 μg/100 g and 47.4–481.4 μg/100 g of folic acid, respectively. The iron and zinc levels were 2.6–7.3 mg/100 g and 0.4–0.9 mg/100 g, respectively, for pizza, and 3.0–12.4 mg/100 g and 0.4–0.8 mg/100 g for bread. The results indicated that the distribution of folic acid and iron in the majority of the samples tested was heterogeneous. This study could be of use to governmental authorities in their food fortification evaluation programs. Moreover, the average iron contents observed in the products could result in problems with zinc absorption, and it is important to consider that iron can induce oxidative stress in cells.  相似文献   

5.
Degradation of added folic acid and native folates in micronutrient‐fortified corn masa and tortillas was evaluated using masa prepared from either nixtamalized corn flour or fresh nixtamal. Variations in masa pH, masa holding time at an elevated temperature, and iron source failed to show significant differences in folate loss in corn flour masa prepared in the laboratory. Masa was subsequently prepared from fresh nixtamal in a commercial mill in Mexico, and fortified with one of two different micronutrient premixes containing iron, zinc, B‐vitamins, and either unencapsulated or lipid‐encapsulated folic acid. Folate loss in commercial masa increased significantly with prebake masa holding time for both premixes. Unencapsulated folic acid showed a 73% loss after 4 hr of holding, compared to 60% loss for encapsulated. The difference was statistically significant, indicating a protective effect from the lipid coating. No significant differences in folate levels were found between prebake masa and baked tortillas. Holding baked tortillas for up to 12 hr also had no effect on folate levels. Native folate showed no significant losses throughout the process. Results from the commercial tortilla mill indicate that most of the loss in added folic acid occurs during prebake holding of masa, possibly from microbial degradation.  相似文献   

6.
The corn tortilla plays an integral role in the Mexican diet and is an ideal vehicle for micronutrient fortification. Approximately 60% of corn tortillas in Mexico are produced from nixtamal, with the remainder prepared from masa flour. A process for continuous fortification of nixtamal tortillas was evaluated in two commercial mills in Mexico. A commercial powder dosifier was used to add micronutrient premix containing iron, zinc, folic acid, niacin, riboflavin, and thiamin to nixtamal (1 g/kg) as it was milled. After training and preliminary sampling, mills produced fortified tortillas unassisted for four weeks. Masa flow rates over a four‐day period were 10–12 kg/min in both plants. Premix flow from the dosifier showed good stability, with an average coefficient of variation of 1.6%. Initial results indicated consistency in the fortification process, with significantly increased variation during the four‐week production period. Fortified tortillas had significantly higher levels of all nutrients tested. Micronutrient losses were <11% in all cases except folic acid, which showed an 80% loss. Despite processing losses, fortification resulted in a nearly fivefold increase in folic acid compared with control tortillas. The new fortification process is technically viable and was well received by millers.  相似文献   

7.
A stable-isotope liquid chromatography-mass spectrometry (LC-MS) assay was developed for the quantitative determination of folic acid in fortified foods. Folic acid was extracted from food samples into a phosphate buffer, purified on a C-18 Sep-Pak cartridge, and analyzed by LC-MS in the negative ion mode using electrospray ionization. The analyte was quantified using (13)C(5)-folic acid as an internal standard. The coefficient of variation for the precision of the method was 5.6% based on the analysis of four sample replicates. The accuracy of the method was assessed using a standard method of addition of folic acid to a shredded whole-wheat cereal. The quantitative determination of folic acid in this matrix was linear over 1 order of magnitude having a concentration range of 2.4 to 24 microg/g of food (or 0.05 to 0.5 microg of analyte injected into the LC-MS). The overall quantitative efficiency of the method was evaluated using a standard reference material (infant formula SRM 1846). The method was applied to the determination of folic acid in several test samples (fortified breakfast cereals), and the values were in accord with the manufacturer's claim. This method advances a LC-MS technique for the determination of folic acid in fortified foods based on stable-isotope dilution methodology. The specificity of the technique and quantitative accuracy of the method in various food substrates suggests that the method may be adapted for routine analysis in other fortified foods.  相似文献   

8.
Nixtamalization is the process of steeping dried corn in hot water with calcium hydroxide (lime) with subsequent removal of all or most of the pericarp through washing. The resulting product is called nixtamal. Approximately 60% of corn tortillas in Mexico are produced from nixtamal, with the remainder prepared from nixtamalized corn flour. Nixtamal was fortified with micronutrient premix containing 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. Added thiamin was almost entirely degraded during processing. Folic acid and riboflavin decreased 26 and 45%, respectively, through the masa‐tortilla manufacturing process. Niacin showed no significant loss. Despite 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.  相似文献   

9.
Five different soybean protein sources were added to wheat flour to increase the protein content by 15–25%, and the resulting composite flours were optimally processed into hot‐press tortillas in a pilot plant. The rheological properties of composite flours were evaluated with the farinograph, alveograph, and other wheat quality tests. Tortilla‐making qualities of the control and soybean‐fortified flours were evaluated during dough handling, hot pressing, and baking. The resulting tortillas were tested in terms of yield, physical and chemical parameters, sensory properties, color, and objective and subjective texture. The soybean‐fortified tortillas had increased yields because of the higher dough water absorption and enhanced essential amino acid scores. Among the five different soybean proteins, the defatted soybean flour (SBM1) with the lowest fat absorption index and protein dispersibility index (PDI) and the soybean concentrate produced the best fortified tortillas. The protein meals with high PDI and relatively lower water absorption index (SBM3 and SBM4) produced sticky doughs, lower alveograph P/L values, and defective tortillas. All soybean proteins produced higher yields of tortillas with an enhanced protein quality and amount of dietary fiber.  相似文献   

10.
After the U.S. mandate of folic acid fortification of enriched grain products, a report indicated higher than expected fortification. Limited information is available on folic acid in enriched products. We measured the folate content in 92 sandwich breads (46 white breads and 46 whole wheat breads) in Birmingham, Alabama, during 2001-2003. The mean folate content in white bread declined significantly from 2001 to 2002 or 2003, whereas the decline in folate content in whole wheat bread containing enriched flour was not significant. White bread contained significantly more folate than whole wheat bread containing enriched flour in 2001 and 2003. In 2002 and 2003, >40% of breads made of enriched flour contained <115 microg of folate/100 g and >70% contained <160 microg/100 g. These percentages were markedly higher than those in 2001. Our data suggest that folic acid in breads containing enriched flour declined after 2001 and monitoring of fortification may be necessary.  相似文献   

11.
不同种类大豆蛋白粉对面包加工特性的影响   总被引：6，自引：2，他引：6  
为探索大豆蛋白作为营养补充剂在面包中应用时，对面团物理特性和焙烤特性产生的影响，该文考察了不同种类的大豆蛋白制品，包括大豆分离蛋白、灭酶全脂粉、活性全脂粉、活性脱脂粉、灭酶脱脂粉对面团粉质特性、拉伸特性和焙烤特性的影响。结果表明，面粉的吸水率与大豆蛋白粉氮溶解指数显著相关，面团的抗拉阻力受大豆蛋白添加量的影响明显。大豆蛋白粉的加入，对面包比体积产生不利影响，下降趋势与大豆蛋白粉对面团拉伸特性的影响显著相关。大豆蛋白粉有软化面包质地的作用，活性全脂粉表现最为明显。大豆蛋白粉的加入量占面粉质量分数的3%时，对面包口感影响不明显，当加入量超过面粉质量分数的7％时，容易出现发粘和豆腥味等现象。  相似文献   

12.
Nine laboratories analyzed samples of whole grain, intermediate, and ready-to-eat products for ethylene dibromide (EDB) residues. Supplied samples of wheat, rice, and flour contained both fortified and incurred EDB; corn bread mix, baby cereal, and bread contained only fortified EDB. The whole grains and intermediates were analyzed by the same basic procedural steps as in the official method for multifumigants: They were extracted by soaking in acetone-water (5 + 1). The baby cereal and bread were analyzed by a modification of the Rains and Holder hexane co-distillation procedure. EDB was determined by electron capture gas chromatography operated with an SP-1000 column. All products contained 3 different levels of EDB and were analyzed as blind duplicates. Overall mean recoveries ranged from 85.2% for 69.6 ppb to 105.0% for 4.35 ppb, both in baby cereal. Interlaboratory relative standard deviations ranged from 5.7% for 869 ppb in wheat to 20.2% for 69.6 ppb in baby cereal, both fortified. Mean levels of incurred EDB in wheat, rice, and flour were 926.7, 982.0, and 49.9 ppb, respectively; corresponding relative standard deviations were 9.9, 7.7, and 13.1%. The method was adopted official first action.  相似文献   

13.
The objective of this research was to identify and define mixing characteristics of gluten‐fortified flours attributable to differences in the method for producing the gluten. In these studies, a wheat gluten concentrate (W‐gluten) was produced using a conventional process model. This model applied physical water displacement of starch (dispersion and screening steps), freeze‐drying, and milling. W‐gluten was the reference or “vital” gluten in this report. An experimental W‐concentrate was produced using a new process model. The new model applied coldethanol (CE) displacement of starch (dispersion and screening steps), freeze‐drying, and milling. Freeze‐drying was used to eliminate thermal denaturation and thereby focus on functional changes due only to the separation method. The dry gluten concentrates were blended with a weak, low‐protein (9.2%), soft wheat flour and developed with water in a microfarinograph. We found that both water and cold‐ethanol processed gluten successfully increased the stability (St) and improved mixing tolerance index (MTI) to create in the blended flour the appearance of a breadbaking flour. Notably, in the tested range of 9–15% protein, the St for CE‐gluten was always higher then the St for W‐gluten. Furthermore, the marginal increase in St (slope of the linear St vs. protein concentration) for the CE‐gluten was ≈57% greater than that for the W‐gluten. The slope of the MTI vs. protein data was lower for the CE‐gluten by 24%. Flour fortified with CE‐gluten exhibited higher water absorption (up to 1.8% units at 13.5% P) than flour fortified with W‐gluten.  相似文献   

14.
A stable isotope dilution assay (SIDA) for the quantitation of N(2)-[1-(carboxy)ethyl]folic acid (CEF) has been developed by using [(2)H(4)]CEF as the internal standard. After sample cleanup by anion exchange chromatography, the three-dimensional specifity of liquid chromatography-tandem mass spectrometry enabled unequivocal determination of the nonenzymatic glycation product of folic acid (FA). When CEF was added to cornstarch, the detection limit for CEF was found to be 0.4 microg/100 g, and a recovery of 98.5% was determined. In analyses of cookies, the intra-assay coefficient of variation was 8.0% (n = 5). Application of the SIDA to commercial cookies produced from wheat flour fortified with FA revealed CEF contents of up to 7.1 microg/100 g, which accounted for approximately 10-20% of the cookies' FA content. In baby foods, multivitamin juices, and multivitamin sweets, however, CEF was not detectable. Further studies on CEF formation during baking of cookies made from fortified flour and different carbohydrates revealed that fructose was most effective in generating CEF followed by glucose, lactose, and sucrose with 12.5, 3.9, 2.5, and 2.5 microg/100 g of dry mass, respectively. During baking, approximately 50% of FA was retained for both monosaccharides fructose and glucose, and 77% as well as 85% of its initial content was retained for the disaccharides lactose and sucrose, respectively. Of the degraded amount of FA, CEF comprised 28% for fructose as well as 18, 12, and 8% for sucrose, lactose, and glucose, respectively. Therefore, CEF can be considered an important degradation product of FA in baked foods made from fructose. To retain a maximum amount of FA, products should rather be baked with sucrose than with reducing carbohydrates.  相似文献   

15.
The objective of this study was to evaluate how Rhyzopertha dominica infestation of stored wheat grain affects the rheological and baking properties of bread made with the milled flour. Wheat samples were infested with R. dominica and stored for up to 180 days at room temperature. Every 45 days, samples of wheat were collected and evaluated for insect population and flour yield. Flour milled from these wheat samples was evaluated for color reflectance, pH, fat acidity, and rheological properties which were measured by a farinograph. Loaves of bread were baked using a straight-dough procedure. Volume, height, and weight of the loaves were evaluated. None of the analyses performed on the control wheat flours showed any changes during the storage period, and they were similar to the initial wheat. The insect population increased during storage of the wheat up to 90 days, and the flour yield decreased with the storage up to 180 days. Flours from insect-infested wheat absorbed more water than did flours from control wheat. Dough stability and dough development times of infested flours decreased. Bread volume showed a progressive decline throughout the storage experiment. In conclusion, flour from insect-infested wheat exhibited changes in rheological properties such as dough stability, dough development times, water absorption, and mixing stability; bread had an offensive odor; and volume and loaf characteristics were negatively affected.  相似文献   

16.
Rice noodles, which are widely consumed noodles in Southeast Asia, were evaluated as a potential carrier for fortificants such as vitamin A, folic acid, and iron. Because flour particle size was found to affect the noodle properties, this study was conducted to investigate the effect of five different particle sizes (≤63, 80, 100, 125, and 140 µm) of dry‐milled rice flour on the cooking quality, microstructure, texture, and sensory characteristics of the rice noodles. The retention of fortificant in the noodles at every stage of processing as affected by the flour particle size was also determined. It was found that the rice noodles produced from flour with the smallest particle size studied (≤63 µm) had the best quality and were the most liked by the consumers. In addition, the noodles had the most compact and regular structure, which could be attributed to having the most severely gelatinized starch. This starch would have caused the least leaching of the fortificant into the surrounding water during the boiling stage of the rice noodle processing. Retention of iron in the cooked fortified rice noodles prepared from flour with the smallest particle size was high at around 87%, whereas that of vitamin A and folic acid were below 15%. Because the losses of the fortificant from the rice noodles were mostly owing to the boiling process, further improvements of the rice noodle processing conditions are required for reduction of the vitamin losses.  相似文献   

17.
Tempering conditions of wheat grain change the quality of the flour, yet most experimental milling systems use a standard tempering without optimization. The effect of tempering condition on milling performance and flour functionality for soft red winter (SRW) wheat grain was tested by measuring flour yield, ash, polyphenol oxidase (PPO), and solvent retention capacity (SRC) in grain samples from three SRW cultivars (Roane, Cyrus, and Severn). Tempering was conducted with a full factorial design of initial wheat moisture, tempered wheat moisture, tempering temperature, and tempering time at two levels. Tempered wheat moisture had the largest effect on milling performance and flour functionality. Flour yield was more reduced for all samples tempered at 15% moisture than for samples tempered to 12% moisture. Flour quality of the 15% tempered sample was better than the 12% tempered samples due to less bran contamination as measured by flour ash and PPO. Increasing the tempering moisture increased flour sucrose SRC and lactic acid SRC but reduced sodium carbonate SRC for samples. Changing tempered wheat moisture changed flour yield and quality much more than did changing the length of time for tempering, the temperature at wheat is tempered, or differences in the initial moisture of the wheat before tempering. The last three effects could be used to improve flour yield in both the 12 and 15% tempered wheat treatment but the detrimental effects of these treatments on flour quality were minimal when combined with the 15% tempered wheat moisture treatment.  相似文献   

18.
Iron deficiency is the most common nutritional disorder worldwide. Iron fortification of foods is considered to be the most cost-effective long-term approach to reduce iron deficiency. However, for fortified foods to be effective in reducing iron deficiency, the added iron must be sufficiently bioavailable. In this study, fortification of whole-grain wheat flour with different sources of iron was evaluated in vitro by measuring the amount of dialyzable iron after simulated gastrointestinal digestion of flour baked into chapatis and subsequent intestinal absorption of the released iron using Caco-2 cell layers. The dialyzability of iron from iron-fortified wheat flour was extremely low. Additions of 50 mg/kg iron to the flour in the form of ferrous sulfate, Ferrochel amino acid chelate, ferric amino acid chelate taste free (TF), Lipofer, ferrous lactate, ferrous fumarate, ferric pyrophosphate, carbonyl iron, or electrolytic iron did not significantly increase the amount of in vitro dialyzable iron after simulated gastrointestinal digestion. In contrast, fortification of flour with SunActive Fe or NaFeEDTA resulted in a significant increase in the amount of in vitro dialyzable iron. Relative to iron from ferrous sulfate, iron from SunActive Fe and NaFeEDTA appeared to be 2 and 7 times more available in the in vitro assay, respectively. Caco-2 cell iron absorption from digested chapatis fortified with NaFeEDTA, but not from those fortified with SunActive Fe, was significantly higher than from digested chapatis fortified with ferrous sulfate. On the basis of these results it appears that fortification with NaFeEDTA may result in whole-grain wheat flour that effectively improves the iron status.  相似文献   

19.
Instant noodles were prepared by substituting hard red winter (HRW) wheat flour with Great Northern bean powder (GNBP) at selected levels (0–60%) using a pilot‐scale noodle processing machine. The functional properties, water absorption, water solubility, and pasting profiles of flour mixtures were tested to verify the process tolerances of ingredients. Prepared noodle samples were evaluated for color, cooking quality, texture, and sensory properties. Slight color differences, an increased cooking loss, and reduced chewiness, cohesiveness, and hardness were observed in cooked noodles that were prepared with GNBP up to 25% of HRW wheat flour weight. The results suggest that HRW wheat flour could be replaced up to 20% (w/w) with GNBP, while still using the conventional processing conditions, to improve the product nutritional value (i.e., increased protein and fiber contents and reduced fat content) (P < 0.05).  相似文献   

20.
Polyphenol oxidase (PPO) has been related to an undesirable brown discoloration of wheat-based end products. Consumer acceptance and product quality are generally decreased by the darkening phenomena. Two sets of wheat samples (Triticum aestivum L.) were investigated for variation in grain and flour PPO levels. Samples included 40 advanced experimental hard white winter wheat lines grown at two Kansas locations and 10 hard red winter wheat genotypes grown at three Nebraska locations. The variability in grain and flour PPO activities was influenced by growing location and population for the hard white wheat samples. There also was a significant influence of population by growing location interactions on PPO activity in both grain and flour. Genotype and growing location both contributed to variability in flour PPO activity among the hard red wheat samples. The variation in flour PPO activities among growing locations appeared larger than variation produced by genotypes tested for the hard red wheat samples. Quality parameters, such as wheat physical properties, flour protein and ash contents, grain color, and milling yield significantly correlated with grain and flour PPO activities. Among red wheat samples, flour PPO activity was related to 100 kernel weight, first reduction flour yield, and flour ash content. Grain PPO activity was related to variation in grain color observed among hard white samples. The relationship of quality characteristics with grain and flour PPO activities varied among white and red wheat samples.  相似文献   

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