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1.
The objective of this work was to study the formation of resistant starch (RS) in tortillas from an ecological nixtamalization process compared with the traditional nixtamalization process. The RS increased through all the steps of tortilla production. It was found that the increase of the RS corresponds mainly to the formation of RS5 (V‐amylose‐lipid complex), but in tortillas two major types of RS coexist: RS5 and RS3 (retrograded starch). In general, tortillas from the ecological nixtamalization process gave higher values of protein, lipids, total dietary fiber, insoluble fiber, soluble fiber, and RS compared with tortillas from the traditional nixtamalization process and commercial flour. The highest glycemic index (GI) occurred in the tortillas from commercial flour, whereas tortillas from 0.4% CaCO3 and 0.6% CaSO4 were classified as medium‐GI (GI 50–70). Tortillas from 0.6% CaCl2 had the lowest value of GI. The ecological nixtamalization processes caused significant differences in quality and nutritional properties of tortillas.  相似文献   

2.
Processing conditions similar to traditional nixtamalization are now used by the industry in the production of dry maize flours (DMF). The objective of this investigation was to evaluate the effect of industrial nixtamalization on maize starch. Thus, dent maize grains were sampled from storage silos and the starch isolated (S). From the same batch of maize, DMF was obtained and the starch isolated (S‐DMF). The amylose content in the starches was quite similar (21.5–23.4%) and characteristic of a dent maize. However, nixtamalization increased the calcium content in S‐DMF. The starches investigated exhibited the typical A‐type diffraction pattern after 40 days of storage at 11–84.1% rh. However, the differential scanning calorimetry (DSC) results showed that annealing of maize starch occurred during storage at 30°C. On the other hand, industrial nixtamalization has both a melting and annealing effect on maize starch. Thus, the operative glass transition temperature (Tg), and the DSC parameters that define starch gelatinization (Tp and ΔH) showed that the proportion between crystalline and amorphous regions within the starch granule and the extent of physical damage to starch were modified by nixtamalization. As an example, Tg for S was between 60 and 62.5°C, while the S‐DMF had a Tg of 45–55°C for damaged starch and 65–70°C for annealed starch. Additionally, the extraction of the nonconstitutive starch lipids provided starches with more consistent thermal properties, particularly in the behavior of gelatinization at different water content. This last observation might have important implications in the consistency of starch physicochemical properties and, consequently, in the quality of maize products such as tortillas.  相似文献   

3.
The phytochemical profiles (total phenolics, anthocyanins, ferulic acid, carotenoids) and antioxidant activities of five types of corn (white, yellow, high carotenoid, blue, and red) processed into masa, tortillas, and tortilla chips were studied. The nixtamalization process significantly (p < 0.05) reduced total phenolics and antioxidant activities when compared to raw grains. Nixtamalized grains exhibited higher concentration of free phenolics and soluble conjugated ferulic acid and had lower concentrations of bound phenolics and ferulic acid than unprocessed grains. Among processed products, there was little difference in the phytochemical contents and antioxidant activities. Among types of corn, the highest concentrations of total phenolics, ferulic acid, and antioxidant activity were observed in the high-carotenoid genotype followed by the regular yellow counterpart. The white corn contained the lowest amount of total phenolics and antioxidant activity. The pigmented blue corn had the highest anthocyanin concentration followed by the red counterpart. These findings suggest that lime-cooking significantly reduced the phytochemical content of nixtamalized products but released phenolics and ferulic acid.  相似文献   

4.
Resistant starch (RS) ingredients are an attractive option to increase dietary fiber in baked products. This study determined the effect of two forms of cross‐linked and pregelatinized cross‐linked RS, Fibersym‐RW (Fsym) or FiberRite‐RW (FRite), respectively, from wheat on dough and tortilla quality and acceptability. Refined wheat tortillas with 0% (control) to 15% RS (flour basis) were made using a standard baking process. Tortillas with 100% whole white wheat were also made. Physical and rheological properties of dough and tortillas, and sensory profile of tortillas were evaluated. Dough with whole wheat and 15% FRite were significantly harder and less extensible than the control dough; this was related to high water absorption of these doughs. Tortillas with whole wheat and 10–15% FRite were less puffed and denser than the control; however these levels of FRite significantly increased tortilla weight (by up to 6.2%). Dough and tortillas with Fsym were comparable to the control. Dietary fiber (g/100 g, db) increased from 2.8 ± 0.3 in control to 14.3 ± 0.5 and 13.6 ± 0.5 in 15% Fsym and 15% FRite tortillas, respectively. Tortillas with whole wheat were less acceptable than the control in appearance, flavor, and texture, while tortillas with 15% Fsym had higher overall acceptability than the control. Incorporation of 15% cross‐linked wheat RS to increase tortilla dietary fiber is feasible without negatively affecting dough handling and tortilla quality.  相似文献   

5.
Fermentation and lactic acid addition enhance iron bioavailability of maize   总被引：1，自引：0，他引：1  
Maize is one of the most important cereal crops for human consumption, yet it is of concern due to its low iron bioavailability. The objective of this study was to determine the effects of processing on iron bioavailability in common maize products and elucidate better processing techniques for enhancing iron bioavailability. Maize products were processed to represent different processing techniques: heating (porridge), fermentation (ogi), nixtamalization (tortillas), and decortication (arepas). Iron and phytate contents were evaluated. Iron bioavailability was assessed using the Caco-2 cell model. Phytate content of maize products was significantly reduced by decortication (25.6%, p = 0.003) and nixtamalization (15%, p = 0.03), and iron content was reduced by decortication (29.1%, p = 0.002). The relative bioavailability (RBA, compared to 100% bioavailability of porridge with FeSO4) of ogi was significantly higher than that of other products when fortified with FeSO4 (p < 0.001) or reduced iron (p < 0.001). Addition of lactic acid (6 mg/g of maize) significantly increased iron solubility and increased bioavailability by about 2-fold (p < 0.01), especially in tortillas. The consumer panel results showed that lactic acid addition does not significantly affect the organoleptic characteristics of tortillas and arepas (p = 0.166 and 0.831, respectively). The results suggest that fermentation, or the addition of small amounts of lactic acid to unfermented maize products, may significantly improve iron bioavailability. Lactic acid addition may be more feasible than the addition of highly bioavailable but expensive fortificants. This approach may be a novel means to increase the iron bioavailability of maize products to reduce the incidence of iron deficiency anemia.  相似文献   

6.
Naturally aflatoxin-contaminated corn (Zea mays L.) was made into tortillas, tortilla chips, and corn chips by the traditional and commercial alkaline cooking processes. The traditional nixtamalization (alkaline-cooking) process involved cooking and steeping the corn, whereas the commercial nixtamalization process only steeps the corn in a hot alkaline solution (initially boiling). A pilot plant that includes the cooker, stone grinder, celorio cutter, and oven was used for the experiments. The traditional process eliminated 51.7, 84.5, and 78.8% of the aflatoxins content in tortilla, tortilla chips, and corn chips, respectively. The commercial process was less effective: it removed 29.5, 71.2, and 71.2 of the aflatoxin in the same products. Intermediate and final products did not reach a high enough pH to allow permanent aflatoxin reduction during thermal processing. The cooking or steeping liquor (nejayote) is the only component of the system with a sufficiently high pH (10.2-10.7) to allow modification and detoxification of aflatoxins present in the corn grain. The importance of removal of tip, pericarp, and germ during nixtamalization for aflatoxin reduction in tortilla is evident.  相似文献   

7.
We studied the effect of steeping time on various physical and chemical properties of maize flour prepared by the traditional nixtamalization process as well as in oversaturated calcium ion conditions. The calcium content of the corn flour was measured by atomic absorption spectroscopy and was correlated with X‐ray diffraction, viscosity, and pH measurements. Calcium content of the flour showed a nonlinear dependence on steeping time, with a local calcium maximum occurring at ≈7 hr. The pH level of the corn flour increased with steeping time, thus roughly following the time trend shown by the steeping time dependence of the calcium content. Flour crystallinity and peak viscosity of water suspensions of the flour reached maximal values at ≈7–9 hr of steeping, in agreement with manufacturing experience showing that these are appropriate steeping times to prepare tortillas with the desirable rheological and organoleptic properties.  相似文献   

8.
The objective of the present work was to study the effect of annealing and concentration of Ca(OH)2 (lime) and calcium salts on the thermal and rheological properties of maize starch during an ecological nixtamalization process. Thermal and rheological properties of maize starch changed during the ecological nixtamalization process because of three main causes: the annealing phenomenon, type of calcium salt, and calcium salt concentration. In all treatments thermal properties (To, Tp, and Tf) of nixtamal starch increased owing to the annealing process, whereas the type of salt or lime increased thermal properties and decreased pasting properties in this order: CaCl2 > CaSO4 > Ca(OH)2 ≈ CaCO3. This behavior was because of the dissociation of each salt or lime in water. Anions (OH−) can penetrate much more easily into the starch granule and start the gelatinization process by rupturing hydrogen bonds. Additionally, amylose‐lipid complexes were formed during the nixtamalization processes, as indicated by an increasing peak at 4.5 Å in X‐ray diffraction patterns.  相似文献   

9.
Yellow and white maize kernels, masas, tortillas, and nejayote solids were analyzed in terms of lutein, zeaxanthin, cryptoxanthin, β‐carotene, and lipophilic antioxidant (AOX) capacity. The germplasm analyzed included two normal yellow maize, two high‐carotenoid genotypes, and one white for comparison purposes. In general, the yellow maize required 34% more lime‐cooking time compared with the white counterpart. Lime‐cooking significantly changed the extractability of carotenoids in masa and tortillas. No carotenoids were detected in the steepwater or nejayote. The lipophilic AOX activity increased 280‐fold from kernel to masa, but only 70% was retained in the baked tortillas. When masa was baked into tortillas, less than 10% of the carotenoids were retained because of the high temperatures used during baking. Interestingly, tortillas made with the maize kernels with the highest carotenoid content did not have the highest amount of these phytochemicals. Therefore, maize varieties should be evaluated based on the carotenoid content in finished food products instead of the amounts originally found in raw kernels.  相似文献   

10.
The objectives of this research were to study the bioavailable calcium from widely used cereals and millets by an in vitro method and to provide data on the role of calcium inhibitors. The average total calcium content of the analyzed raw cereals and millets ranged from 10.2 to 324.6 mg/100 g (the lowest and highest values correspond to maize and finger millet, respectively), whereas the rest of the raw cereals and millets had calcium content in the range of 26.3–50.4 mg/100 g, except for rice samples (10.4 mg/100 g). Soluble percentage of calcium is the highest in maize (45.1%), and dialyzable calcium percentage is the highest in wheat (34.9%). The cooking process did not significantly affect calcium bioavailability and the contents of phytate and tannin. However, cooking reduced the oxalate content, and in the case of dietary fiber significant increase was observed. The order of oxalate content in the cereals and millets studied was found to be pearl millet > finger millet > wheat > maize > sorghum > rice. Multiple regression analysis carried out to explain the influence of oxalate, phytate, tannin, and dietary fiber on calcium bioavailability showed greater inhibitory effect of oxalate.  相似文献   

11.
A high‐amylose, non‐floury corn, a floury corn, and a 1:1 blend were made into masa and then tortillas. The masa flour made with the high‐amylose corn had a greater amount of resistant starch (RS 28.8%) and a greater amount of total dietary fiber (TDF 42.1%) than that with the floury corn (RS 2.9%, TDF 9.6%), producing a high‐fiber tortilla. The masa was evaluated for pasting properties using a Rapid ViscoAnalyser (RVA). The high‐amylose masa slurry gelatinized little at 95°C. The floury masa had the greatest peak viscosity, whereas the 1:1 blend was intermediate in value. Sensory evaluations of the tortillas for the textural attributes showed the floury tortillas to be chewier, more rollable, and grittier than the high‐amylose tortillas, whereas the blend tortillas were intermediate for most attributes. The cutting force of the high‐amylose tortillas, measured on a texture analyzer, was very low; the blend and floury tortillas required more force. Chewiness was correlated to rollability (r = 0.99, P = 0.05). The %RS and %TDF were correlated to rollability (r = –0.99), and cutting force (r = 0.99). The floury and blend tortillas had firm textures expected of desirable tortillas, whereas the high‐amylose tortillas broke under little force, and would not roll. The high‐amylose tortillas had high amounts of RS and TDF but poor texture. The blend tortillas retained most floury tortilla textural properties, making them suitable products for consumer use.  相似文献   

12.
White and blue corns of Mexican and American origins were lime-cooked to obtain nixtamals with optimal moisture (48–50%) for tortillas and chips. Blue kernels had less bulk density, softer endosperm and, consequently, required less cooking time than the white kernels. The optimum cooking regime for the white kernels was 100°C for 20 min, while the optimum for both pigmented genotypes was 90°C for 0 min (until the lime-cooking solution reached 90°C). Doughs, tortillas, and chips were characterized by total soluble phenolics (TSP), anthocyanins (ACN), and antioxidant capacity (AOX). A dough acidification procedure using fumaric acid (pH 5.2) was assessed as a means to improve TSP, ACN, and AOX retention. The Mexican blue corn had higher AOX (16%) than the American blue genotype, although the latter had a threefold higher TSP content (12.1 g/kg, dwb). Mexican and American blue corns had higher AOX capacity (29.6 and 25.6 μM trolox equivalents [TE]/g dwb), respectively, than the white corn (17.4 μM TE/g). White corns did not have detectable amounts of ACN, while blue Mexican and American kernels contained 342 and 261 mg/kg. Lime cooking had the greatest negative impact on the stability of TSP, ACN, and AOX. However, the acidification reduced ACN, TSP, and AOX losses by 8–23, 3–14, and 4–15%, respectively. Similar ACN losses were observed for both types of blue kernels when processed into nixtamal/dough (47%); however, ACN losses in tortillas and chips manufactured from the American blue genotype were higher (63 and 81%, respectively) than those of Mexican blue corn products (54 and 75%). ACN losses were highly correlated to TSP (r = 0.91) and AOX capacity losses (r = 0.94).  相似文献   

13.
Studies were undertaken to determine the fate of the mycotoxins, fumonisins, during the process of alkaline cooking (nixtamalization), using normal-appearing corn that was naturally contaminated with fumonisin B(1) (FB(1)) at 8.79 ppm. Corn was processed into tortillas, starting with raw corn that was cooked with lime and allowed to steep overnight; the steeped corn (nixtamal) was washed and ground into masa, which was used to make tortillas. Calculations to determine how much of the original fumonisin remained in the finished products took into consideration that FB(1) will be converted to hydrolyzed fumonisin B(1) (HFB(1)) by the process of alkaline cooking. All fractions, including steeping and washing water, were weighed, and percent moisture and fumonisin content were determined. Tortillas contained approximately 0.50 ppm of FB(1), plus 0.36 ppm of HFB(1), which represented 18.5% of the initial FB(1) concentration. Three-fourths of the original amount of fumonisin was present in the liquid fractions, primarily as HFB(1). Nixtamalization significantly reduced the amount of fumonisin in maize.  相似文献   

14.
Our report shows the calcium ion diffusion process through the different parts of maize kernels (pericarp, endosperm, and germ) during the traditional nixtamalization process as a function of steeping time (t) 0–24 hr. The cooking step of the nixtamalization process used 3 kg of maize kernels in 6L of water and 2% calcium hydroxide (w/w). The cooking temperature was 92°C for 40 min. The calcium content of the samples was measured using atomic absorption spectroscopy. We found that the whole instant corn flour, pericarp, endosperm, and germ, had a nonlinear relationship to steeping time, showing a local maximum at 9 hr. Analysis of the different parts of the nixtamalized kernels showed that in short steeping times (0–5 hr) calcium diffusion took place mainly in the pericarp. Calcium diffusion in the endosperm and germ occurred gradually over longer steeping times. However, the physical state of the kernels (broken kernels) accelerated the diffusion process. Calcium diffusion occurred first in the pericarp, followed by the endosperm and germ. Immediately after cooking (t = 0 hr), we found a 1.148% calcium content in the pericarp, 0.007% in the germ, and 0.028% in the endosperm. After 24 hr of steeping, the calcium contents were 2.714% in the pericarp, 0.776% in the germ, and 0.181% in the endosperm. In another study, the calcium content in the endosperm was measured by first separating the 10% from the outermost, followed by another 10% from the next endosperm tissue, and concluding with the remaining 80%. Calcium ions were present mainly in the outermost layers of the endosperm. The damaged kernels steeped for more than 5 hr showed greater calcium concentrations than the undamaged counterparts.  相似文献   

15.
Mexico has the largest diversity of genetic resources for maize in the world, with about 59 different landraces. However, little is known about their wet‐milling characteristics. The aim of this study was to determine whether 15 Mexican blue maize (Zea mays L.) genotypes of Elotero de Sinaloa landrace collected in the northwestern region of Mexico have suitable wet‐milling properties. Great variability of physical, compositional, and wet‐milling characteristics among these blue maize genotypes was observed. The FAUAS‐457 and FAUAS‐488 maize genotypes had similar starch yield and starch recovery as reported for the wet‐milling industry, which indicated that they may be useful as a source of extractable starch. Residual protein levels in the starch fractions were in the range of 0.39–0.68%, and total solids recovery exhibited a mean value of 98.8%, indicating acceptable efficacy of the wet‐milling process. This process afforded starches from blue maize genotypes with low protein contents. Wet‐milling fractions correlated with the physical and chemical properties of the kernels. Our results indicate that Mexican blue maize genotypes contain characteristics that make them appropriate and utilizable at the industrial level, and they can also be valuable for improving wet‐milling characteristics of maize through breeding programs.  相似文献   

16.
Pigeon pea (Cajanus cajan var. aroíto) seeds were fermented in order to remove antinutritional factors and to obtain functional legume flour to be used as pasta ingredients. Fermentation brought about a drastic reduction of alpha-galactosides (82%), phytic acid (48%), and trypsin inhibitor activity (39%). Fermented legume flours presented a notable increase of fat and total soluble available carbohydrates, a slight decrease of protein, dietary fiber, calcium, vitamin B2, vitamin E, and total antioxidant capacity, and a decrease of soluble dietary fiber, Na, K, Mg, and Zn contents. No changes were observed in the level of starch and tannins as a consequence of fermentation. The fermented flour was used as an ingredient to make pasta products in a proportion of 5, 10, and 12%. The supplemented pasta products obtained had longer cooking times, higher cooking water absorptions, higher cooking loss, and higher protein loss in water than control pasta (100% semolina). From sensory evaluations, fortified pasta with 5 and 10% fermented pigeon pea flour had an acceptability score similar to control pasta. Pasta supplemented with 10% fermented pigeon pea flour presented higher levels of protein, fat, dietary fiber, mineral, vitamin E, and Trolox equivalent antioxidant capacity than 100% semolina pasta and similar vitamins B1 and B2 contents. Protein efficiency ratios and true protein digestibility improved (73 and 6%, respectively) after supplementation with 10% fermented pigeon pea flour; therefore, the nutritional value was enhanced.  相似文献   

17.
Using a continuous decorticating machine, white dent corn was efficiently separated, after brief steeping in water, into two fractions: the first (12.5%) consisting mainly of pericarp, germ, and tip cap (PGT); the second (87.5%) consisting of endosperm. Nixtamalization of the maize fractions in the presence of 0.6% (w/w) lime caused an increase in the hot‐paste viscosity at 90°C, while nixtamalization of PGT at lime inputs <0.6% (w/w) resulted in decreased viscosity. Three domains were found for the viscosity of nixtamalized endosperm at 90°C: lower concentrations of lime (< 0.15%, w/w) resulted in lower viscosity values; increased lime (0.15% – <0.3%, w/w) increased the viscosity values; and a lime concentration of 0.3% (w/w) resulted in a lower viscosity value. The response variables (water absorption index, water solubility index, initial viscosity, and viscosity at 90°C for nixtamalized PGT, and compression force and compression area of tortillas) indicated that the mathematical models fit the experimental data and the variance of the models was highly significant. Tortillas of good functional characteristics similar to tortillas produced by the traditional process were obtained when 5% nixtamalized fractions of PGT were blended with 95% nixtamalized endosperm.  相似文献   

18.
Two different germplasms of a white variety and one germplasm of a black variety of Mucuna pruriens var. utilis were evaluated for their physicochemical properties as well as their nutritional and antinutritional characteristics. All germplasms had higher grain weight, density, hydration, and swelling capacity than other common legumes. The dehulled samples contained 303.2-335.5 g(-1) protein and 46.1-53.5 g x kg(-1) lipid, and these values were higher than the respective whole seeds. The levels of macro- and microelements in both whole and dehulled seeds were comparable to those in common pulses. All germplasms had a high dietary fiber content (18-19.5%), made up of mainly insoluble dietary fiber (DF). Seed lipids were high in unsaturated fatty acids (64.7-66.9%), specifically linoleic acid (48-49%). Whole and dehulled seeds of the white variety from Salem were particularly rich in sulfur-containing amino acids with significantly higher levels of in vitro protein digestibility than the other two germplasms. All germplasms had high levels of total phenols and phytate, trypsin, and chymotrypsin inhibitor activities, but were low in tannins, saponins, and alpha-amylase inhibitor activity. Only weak hemagglutinating activity against cow erythrocytes and no hemagglutinating activity against human erythrocytes (O) was observed in all the samples. Dehulled seeds were higher in total starch, including resistant starch and oligosaccharides (with verbascose as the major fraction) than the respective whole seeds. Both whole and dehulled samples of the white variety of Salem germplasm showed significantly lower concentrations of L-dopa, nonmethylated, and methylated tetrahydroisoquinolines than the respective whole and dehulled samples of other germplasms. In general, dehulling didn't affect the overall nutritional status in any of the presently investigated samples.  相似文献   

19.
《Cereal Chemistry》2017,94(2):277-283
Sorghum bran (SB) is a good source of phenolic compounds with high antioxidant capacity that increases the antioxidant activity (AOX) of tortillas prepared with extruded nixtamalized corn flour. The objective of this research was to study the effects of bran addition (0, 5, or 10%) before (ENBESB) or after (ENAFSB) extrusion, in the features and composition of baked tortillas in terms of total phenolic compounds (TPC), AOX, color (L , a , b, hue, chroma, and E value), and tortilla firmness. It was possible to retain more than 81.8 and 89.9% of TPC and AOX, respectively, in ENBESB‐10% flour. Tortillas prepared with ENAFSB‐10% flour retained more than 92 and 76% of TPC and AOX, respectively, compared with ENBESB. However, tortillas elaborated with ENAFSB flour showed a higher firmness and lower flexibility than counterparts produced from ENBESB. The use of extrusion to produce nixtamalized corn flours and the strategy of adding the SB to the corn meal before extrusion were essential to retain TPC and AOX and, additionally, to enhance texture of tortillas.  相似文献   

20.
《Cereal Chemistry》2017,94(1):98-103
Dehulled and/or germinated black bean flours were physicochemically characterized, including pasting properties, along with the trypsin inhibitor and antioxidant phenolics. To our best knowledge, this is the first study that, using nonparametric correlations and principal component analysis, identifies the parameters affecting the pasting properties of germinated black bean flour. The carbohydrate loss observed after black bean germination was indirectly correlated with the crude fiber content. Therefore, germination increased the protein and crude fiber contents compared with raw seeds (from 19.1 and 2.4% to 24.0 and 5.1%, respectively). Additionally, the highest protein digestibility was obtained in dehulled germinated black bean flour (78.4%), followed by whole germinated seed flour (74.1%). The dehulling process increased the total starch content 13.5 and 18.8% compared with raw and germinated whole bean flours, respectively. Dehulling decreased both trypsin inhibitor activity and antioxidant phenolics. Germination reduced by twofold the peak and final viscosities of black bean flours. Interestingly, both viscosities were negatively correlated with protein and positively correlated with fat and insoluble dietary fiber. Although resistant starch content was not affected by germination or dehulling, its interactions with fat and insoluble dietary fiber were responsible of the changes observed in pasting properties of germinated black bean flour.  相似文献   

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