High oil content maize: Physical, thermal and rheological properties of grain, masa, and tortillas

lable at ScienceDirect

LWT - Food Science and Technology xxx (2014) 1e6

Contents lists avai

LWT - Food Science and Technology

journal homepage: www.elsevier .com/locate/ lwt

High oil content maize: Physical, thermal and rheological properties ofgrain, masa, and tortillas

María Gricelda V�azquez-Carrillo a, *, David Santiago-Ramos b, Marcela Gayt�an-Martínez b,Eduardo Morales-S�anchez c, Manuel de Jesús Guerrero-Herrera d

a INIFAP-CEVAMEX, Km. 13.5 Carretera Los Reyes-Texcoco, Coatlinchan, Texcoco, Estado de M�exico C.P. 56250, M�exicob PROPAC, UAQ, Cerro de las Campanas S/N, Col. Las Campanas, Quer�etaro, Quer�etaro C.P. 76010, M�exicoc CICATA-IPN, Unidad Quer�etaro, Cerro Blanco No. 141, Col. Colinas del Cimatario, Quer�etaro, Quer�etaro C.P. 76090, M�exicod INIFAP-CIRNO, Calle Norman E. Borlaug Km 12, Cd. Obreg�on, Sonora C. P. 85000, M�exico

a r t i c l e i n f o

Article history:Received 23 April 2014Received in revised form21 July 2014Accepted 29 July 2014Available online xxx

Keywords:Grain qualityHigh-oil maizePasting propertiesTortilla quality

* Corresponding author. Tel.: þ52 (595) 9212638x1E-mail addresses: [email protected] (M

[email protected] (D. Santiago-Ramos), mar(M. Gayt�an-Martínez), [email protected] (E. [email protected] (M.J. Guerrero-Herrera).

http://dx.doi.org/10.1016/j.lwt.2014.07.0430023-6438/© 2014 Elsevier Ltd. All rights reserved.

Please cite this article in press as: V�azquez-Cmasa, and tortillas, LWT - Food Science and T

a b s t r a c t

The objective of this study was to assess thermal, rheological and quality properties of grain, masa(ground nixtamalized corn), and tortillas made with high-oil maize hybrids and compare them withlandraces. Grains of high-oil hybrids were harder (flotation index 10e36) with high onset, peak and finalgelatinization temperatures, which were reflected in lower masa and tortilla yield. However, the tortillashad higher oil content (3.2e4.5 g/100 g) than those made with landraces (2.9e3.0 g/100 g). Tortillasmade with the yellow hybrids were softer (1.8 N). Pepitilla had the highest viscosity in grain, masa andtortillas, reflected in greater water absorption and masa and tortilla yield (1.61 kg/kg maize). A closerelationship was found between G0 and G00 and retained pericarp and oil content in masa; higher contentof natural gums produced firmer masa with higher viscoelasticity. The high oil content in tortillasreduced their water absorption and starch swelling capacity but inhibited starch retrogradation, so theyremained softer during storage.

© 2014 Elsevier Ltd. All rights reserved.

1. Introduction

Maize (Zea mays L.) is the cereal that is most produced andconsumed in Mexico. It is mostly used for making tortillas, whichare still the most important component of the Mexican diet.Approximate per capita consumption in rural areas is 79.5 kg peryear, while in urban areas it is 56.7 kg per year (SE-DGIB, 2012).Tortillas are made from fresh ground nixtamal (masa) or nixta-malized flour (dehydrated masa). To obtain nixtamal, maize iscooked in water with lime, steeped for 12e16 h and then washedand ground to obtain the masa (Flores-Farías et al., 2000) withwhich tortillas are made. The physicochemical, rheological andtextural properties of the masa and the end quality of the tortillasdepend on both maize type and conditions of the nixtamalizationprocess. The lime acts on the components of the grain cell wall and

06..G. V�azquez-Carrillo), [email protected]�anchez), guerrero.

arrillo, M. G., et al., High oilechnology (2014), http://dx.d

converts the hemicellulose into soluble gums. Moreover, thisthermal-alkaline treatment gelatinizes part of the starch, saponifiessome lipids and solubilizes part of the proteins (Mendez-Montealvo, S�anchez-Rivera, Paredes-L�opez, & Bello-P�erez, 2006).Changes in the texture of high-starch products are associatedmainly with the phenomena of starch gelatinization and retrogra-dation. In the case of tortillas, retrogradation and rate of dehydra-tion are the factors responsible for hardening, an undesirablecharacteristic since consumers prefer soft tortillas. To preventhardening, gums and hydrocolloids are used, although the additionof pericarp, lipids and enzymes directly to the masa has also beenproposed (Ar�ambula-Villa, Guti�errez-Arias, & Moreno-Martínez,2007).

During the thermal-alkaline treatment, lipids interact withamylose molecules, affecting starch physicochemical properties.Ar�ambula-Villa, Gonz�alez-Hern�andez, and Ordorica-Falomir (2001)reported that elimination of all free lipids from the masa producestortillas of unacceptable quality. These same authors found that theaddition of 0.5 g/100 g maize lipids to nixtamalized maize flourdecreases the rate of dehydration and improves masa and tortillatexture. Moreover, Vidal-Quintanar, Love, and Johnson (2001)indicate that the presence of oil significantly improves tortilla

content maize: Physical, thermal and rheological properties of grain,oi.org/10.1016/j.lwt.2014.07.043

Delta:1_given name

Delta:1_surname

Delta:1_given name

Delta:1_surname

Delta:1_given name

mailto:[email protected]







www.sciencedirect.com/science/journal/00236438

http://www.elsevier.com/locate/lwt

http://dx.doi.org/10.1016/j.lwt.2014.07.043



M.G. V�azquez-Carrillo et al. / LWT - Food Science and Technology xxx (2014) 1e62

firmness and chewiness. Recently, V�azquez-Carrillo et al. (2014)used hybrids with high oil content (HOC) and found that the tor-tillas had a softer texture and greater elongation, both recentlymade and stored for up to 72 h in refrigeration, relative to thetortillas made from maize with low oil content. Thus, theyconcluded that HOC maize varieties are a good option for makinggood sensorial and nutritional quality tortillas.

The objective of this study was to assess and compare thethermal, rheological and grain quality properties of grain, masa andtortillas of maize landraces with those of high oil content hybridmaize varieties.

2. Materials and methods

2.1. Biological material

The genotypes used in this study are presented in Table 1. Allwere grown in the 2009 springesummer crop cycle on the exper-imental sites of the National Institute of Research in Forestry,Agriculture and Livestock (INIFAP).

2.2. Physical characteristics and oil content of grain

In grain, floatation index (FI), as an indirect measure of hardness(SAGARPA, 2002, p. 14e15), and percentage of pedicel, pericarp,germ and endosperm (Gonz�alez, 2009) were assessed. In grain andtortilla, oil was analyzed by method 30-25.01 (AACC, 2000).

2.3. Nixtamalization process and quality variables of nixtamal andtortilla

Nixtamalization consisted of cooking 100 g maize with 0.7 gCa(OH)2 and 200 mL water. Nixtamalization time was assigned inaccordance with the flotation index (FI ¼ 0e12%, 45 min;FI ¼ 13e38%, 40 min; FI ¼ 39e62%, 35 min; FI ¼ 63e87%, 30 min;FI¼ 88e100%, 25min). After cooking, the nixtamal was steeped for16 h, and then washed with 200 mL water to discard the cookingliquid (nejayote) and ground in a stone mill to obtain a finetextured masa. To make the tortillas, 20 g portions of masa werepressed with a metallic tortilla press to make discs of approxi-mately 15 cm in diameter; these were baked on ametal griddle at atemperature of 260 ± 10 �C for 17 s on one side to form a thin layer,50 s on the opposite side, and finally 17 s on the side of the thinlayer to allow it to inflate. The tortillas were cooled at room tem-perature, packed in commercial polyethylene bags and stored in adomestic refrigerator at 4 �C. The content of solids in the nejayote(cooking water), pericarp retained in the nixtamal, and masa andtortilla yield were measured V�azquez-Carrillo, Garcia-Lara, Sali-nas-Moreno, Bergvinson, & Palacios-Rojas (2011). Moisture in

Table 1Identification and origin of the genotypes studied.

Genotype Typea Provenance

Chalque~no Landrace Texcoco, Edo.M�exico

Pepitilla Landrace Iguala, GuerreroWPN (White Population from the

Northwest)HOCHybrid

Cd. Obreg�on, Sonora

WPB (White Population from the Bajío) HOCHybrid


YPN (Yellow Population from theNorthwest)

HOCHybrid


YPB (Yellow population from the Bajío) HOCHybrid


a HOC: high oil content.

Please cite this article in press as: V�azquez-Carrillo, M. G., et al., High oilmasa, and tortillas, LWT - Food Science and Technology (2014), http://dx.d

masa and tortillas was determined with AACC method 44-19.01(AACC, 2000).

2.4. Grain thermal analysis

Thermal properties of the grain were examined using differen-tial scanning calorimetric equipment (DSC1 STARe System MettlerToledo®) previously calibrated with indium standard using themethod proposed by Narv�aez-Gonz�alez, Figueroa-C�ardenas, Taba,and Rinc�on (2006).

2.5. Viscoamylographic profile

To determine the viscosity profile of the ground grain, masa andtortillas, the AACC method 61-02.01 (AACC, 2000) was used withmodifications proposed byM�enera-L�opez, Gayt�an-Martínez, Reyes-Vega, Morales-S�anchez, and Figueroa (2013). The samples wereexamined with a rheometer (Anton-Paar Model Physica MCR 101)equipped with an accessory for measuring viscosity (model ST24-2D). Each sample was prepared with 18 mL distilled water and3 g of sample. The temperature profile used for the analysis washeating from 50 to 92 �C at a rate of 6 �C min�1. The temperaturewas maintained at 92 �C for 6 min and cooled from 92 to 50 �C at arate of 6 �Cmin�1. This treatment was replicated on each sample. Inthe case of masa, the samples were previously dried at 45 �C for24 h, ground, and sifted through a US 60 mesh.

2.6. Rheological properties: viscoelasticity

Samples of masa were examined with an Anton-Paar ModeloPhysica MCR 101 rheometer with a system of parallel plates (PP25/S) 25 mm in diameter. The analysis was conducted in duplicate onportions of 3 ± 0.007 g masa with 50 g/100 g moisture. During thetest, temperature was maintained constant at 25 �C. The method-ology to measure viscoelasticity comprised two phases: First, thelinear viscoelastic region (LVR) was determined with an amplitudesweep performed from 0.01 to 10% strain at a frequency of 1 Hz. Theamplitude sweep showed that LVR for this material was between0.01 and 1% strain. Therefore, the value taken was 0.1% constantstrain. Second, a 0.1e10 Hz frequency sweep was performed with0.1% constant strain. The values of G0 (elastic module) and G00

(viscous module) were recorded with the software that comes withthe equipment.

2.7. Tortilla texture

Breaking force was measured with a texturometer Brookfield®

(model CT3, Middleboro, MA, USA). A 5 cm tortilla disc was placedbetween two 1 cm thick metal plates, which had a 2 cm diameterorifice; through this orifice passes a spherical accessory (19.05 mmin diameter). The accessory travels at a speed of 1 mm s�1. Whenthe sphere makes contact with the tortilla, the tortilla stretchesuntil it breaks; this breaking point is known as maximum breakingforce. The distance the sphere travels after making contact andbefore the tortilla breaks is called elongation and is reported inmm.

2.8. Statistical analysis

All of the assessments were duplicated under a completelyrandomized design. The results were analyzed with an analysis ofvariance (one-way ANOVA), means were compared by Tukey's test(the significance at p < 0.05 was determined), and simple correla-tion analysis was performed. All statistical calculations were donewith SAS software for Windows, version 9.0.


Table 2Physical characteristics and oil content in grainb.

Genotype FIa (%) Hardnessa Pedicel Pericarp Germ Endosperm Oil

(g/100 g)

Chalque~no 83 b S 1.8 b 5.9 bc 11.2 ab 81.0 a 5.8 cPepitilla 100 a VS 2.6 a 7.0 a 10.2 b 80.2 a 4.2 eWPN 19 d H 1.3 b 5.3 c 11.5 ab 81.8 a 5.5 cdWPB 36 c H 1.3 b 5.5 bc 11.5 ab 81.6 a 6.3 bYPN 10 e VH 1.7 b 6.1 b 12.0 a 80.2 a 6.8 aYPB 11 e VH 1.4 b 5.9 bc 11.2 ab 81.5 a 5.2 d

a FI ¼ Flotation index; VH¼Very hard, if FI ¼ 0e12%, H ¼ hard if FI ¼ 13e37%,I¼Intermediate if FI ¼ 38e62%, S¼Soft if FI ¼ 63e87%, VS ¼ very soft ifFI ¼ 88e100%.

b Means with different letters in the same column are statistically significantdifferent (p < 0.05) according to the Tukey test.

M.G. V�azquez-Carrillo et al. / LWT - Food Science and Technology xxx (2014) 1e6 3

3. Results and discussion

3.1. Physical characteristics and oil content of grain

Highly significant differences (p � 0.01) were observed amonggenotypes in physical characteristics and grain oil content (Table 2).The maize genotypes with high oil content (HOC) were the hardest,while the landraces were softer and, specifically, Pepitilla was thesoftest (FI ¼ 100%). The nixtamalized flour industry (NFI) demandsmaize with FI � 40%, while the masa and tortilla industry (MTI)requires grains of soft or intermediate hardness (FI > 40%) that havehigh capacity for water absorption to obtain high masa and tortillasyields (V�azquez-Carrillo et al., 2011). Under this scheme, the HOCgenotypes could be used by the NFI and the landraces by the MTI.Pepitilla had the highest content of pedicel and pericarp and thelowest content of germ and endosperm. Between the HOC hybridsand Chalque~no, there were no significant differences in content ofthese components (Table 2). In the maize grain, oil is found mainlyin the germ, so that when the germ is large, there is a higher oilcontent (Lambert, Alexander, & Han, 1998). This relationship wasdemonstratedwith the positive correlation found between grain oilcontent and proportion of germ (r ¼ 0.85, p < 0.01). No genotypeexceeded the maximum of 12 g/100 g germ required by the nix-tamalized flour industry. HOC hybrids and Chalque~no had thehighest percentages of oil (>5.2 g/100 g) (Table 2). YPN (YellowPopulation from the Northwest) was outstanding, with the highestoil content (6.8 g/100 g) similar to that reported for this genotypeby V�azquez-Carrillo et al. (2014).

3.2. Pasting and thermal properties of the grain

The analysis of variance revealed significant differences in theviscosity parameters and onset gelatinization temperature amongthe maize genotypes studied (Table 3). The highest peak viscositywas found in Pepitilla (2534 cP), which was the genotype with the

Table 3Grain viscosity propertiesa,b in maize landraces and high-oil content hybrids.

Genotype PT (�C) PV (cP) MV (cP) FV (cP)

Chalque~no 77.87 a 2269 b 1317 b 4441 aPepitilla 73.20 d 2534 a 850 e 2973 dWPN 75.48 bc 1970 c 1507 a 3823 bWPB 75.59 b 1567 d 1301 b 3646 bcYPN 75.96 b 1703 d 1033 c 3399 cYPB 74.55 c 1363 e 951 d 2815 d

a PT ¼ pasting temperature; PV ¼ peak viscosity; MV ¼ minimum viscosity;FV ¼ final viscosity.



softest grain (FI ¼ 100%). According to Narv�aez-Gonz�alez et al.(2006), genotypes with soft grains develop high viscositiesbecause starch granules are larger and less compacted, facilitatingdiffusion of water within the grain. They require less time and lessheat to gelatinize than those that have lower peak viscosities. TheHOC genotypes that had hard grains developed low relative vis-cosity and required higher temperature and a longer gelatinizationtime. This is because hard grains have a higher degree of compac-tion than soft grains and a very dense proteinmatrix that surroundsthe starch granules, impeding rapid diffusion of water through theendosperm. Narv�aez-Gonz�alez et al., (2006) state that those grainswith high viscosity peaks develop a high final viscosity and viceversa; this behavior, however, was not evidenced in our study. TheChalque~no genotype had a different viscosity profile: it had rela-tively high viscosity, typical of soft grains, but required more timeand higher temperature to gelatinize than the other genotypes dueto the oil content (5.8 g/100 g) of this native grain. Those genotypeswith higher oil content had higher minimum and final viscosityvalues, while Pepitilla and YPB (Yellow Population from the Bajío),with low oil content grain, had the lowest values (Table 3).Takahashi and Seib (1988) demonstrated that an increase in thelipid content of maize starch produces an increase in pastingtemperature, minimum viscosity and final viscosity. This result isexplained by the large quantity of lipids that favor the formation ofamyloseelipid complexes during cooking. These complexes breakdown when they reach high temperatures, but reorder during thecooling cycle, contributing to preserving the granular structure.

Peak gelatinization temperatures of the genotypes studied werebetween 69.94 and 75.39 �C, and the enthalpies were between 2.72and 5.29 J g�1 (Fig. 1). These data are in accordance with thosereported for other maize genotypes cultivated in Mexico (M�endezet al., 2005; Narv�aez-Gonz�alez et al., 2006). Pepitilla exhibitedthe lowest gelatinization temperature, while Chalque~no had thehighest. This means that the Chalque~no starch granules require ahigher temperature to initiate the gelatinization process. Thesevalues are important in determining maize and maize productcooking variables. According toM�endez et al. (2005), the genotypesthat require higher gelatinization temperatures, such as Chalque~noand high-oil maize hybrids, can be used in the production of maizeflour because of the high temperatures used during processing,while those that do not require high temperatures, such as Pepitilla,would be used to make tortillas by the traditional nixtamalization

Fig. 1. Thermal properties of maize landraces and high-oil hybrids.


Table 4Quality of nixtamal and tortillasa,b made from maize landraces and high-oil hybrids.

Genotype PR DML MM TM MY TY BF E OilT

(g/100 g) kg/kg maize N mm (g/100 g)

Chalque~no 40.0 c 3.1 c 57.3 b 44.3 b 1.99 ab 1.58 ab 1.96d 10.1 b 2.9 ePepitilla 49.4 a 2.8 d 58.4 a 47.0 a 2.12 a 1.61 a 2.29c 11.9 a 3.0 eWPN 48.5 a 3.6 b 56.5 bc 43.7 b 1.98 ab 1.56 b 2.58a 10.8 ab 3.2 dWPB 42.2 b 3.0 c 57.4 ab 44.1 b 1.98 ab 1.55 bc 2.39b 10.5 b 3.7 cYPN 37.9 d 3.8 a 55.9 c 43.7 b 1.93 ab 1.50 cd 1.78e 9.6 b 4.0 bYPB 36.5 d 3.6 b 57.0 bc 41.5 c 1.92 b 1.48 d 1.81e 9.9 b 4.5 a

a PR ¼ pericarp retained in the nixtamal; DML ¼ dry matter loss; MM ¼ masa moisture content; TM ¼ tortilla moisture content; MY ¼ masa yield; TY ¼ tortilla yield;BF ¼ tension breaking force; E ¼ Extensibility; OilT ¼ tortilla oil content.

b Means with different letters in the same column are statistically significant different (p < 0.05) according to the Tukey test.


process since it would save energy. The high gelatinization tem-perature and enthalpy of Chalque~no may be due to the molecularstructure of the amylopectin present in these starches. According toSandhu and Singh (2007), high gelatinization temperature andenthalpy reflect a high percentage of crystallinity of the amylo-pectin; thus a larger amount of energy is required to fuse its crys-tallites. Higher gelatinization enthalpies were found in the softgrain genotypes than in hard grain genotypes, coinciding with thereports of Narv�aez-Gonz�alez et al. (2006).

3.3. Nixtamal and tortilla quality

Nixtamal and tortilla quality variables (Table 4) were statisti-cally different (p � 0.01) among genotypes. More pericarp wasretained by the nixtamal made with Pepitilla and WPN (WhitePopulation from the Northwest) than by nixtamal made with othergenotypes. Rapid hydrolysis facilitates penetration of water andelimination of the pericarp when the nixtamal is washed, but anexcessive elimination of pericarp reduces the amount of naturalgums and can thus negatively affect textural properties of the masaand tortillas (Martínez-Bustos, Martínez-Flores, Sanmartín-Martínez, S�anchez-Sinencio, Chang, Barrera-Arellano, & Rios,2001). The MTI prefers maize whose nixtamal retains more than30 g/100 g of the pericarp (V�azquez-Carrillo et al., 2011); all of themaize genotypes comply with this requirement. For the qualityvariable dry matter loss, yellow HOC genotypes had higher drymatter loss than the white genotypes and landraces. All of thematerials had dry matter loss of less than the 5.0 g/100 g acceptedby the industry (Table 4). The masa moisture content was related tomasa yield and, consequently, high values of moisture result in hightortilla yield. Pepitilla had the highest yield of tortillas and YPB thelowest. Another quality variable that differentiated maize varietieswas oil content. Highly significant (p � 0.01) differences wereobserved, and these differences had repercussions in other vari-ables. Yellow maize varieties with high oil content (YPN and YPB)produced softer (1.89 N), less extensible (9.7 mm) tortillas, while

Table 5Pasting propertiesa,b of masa from maize landraces and high-oil hybrids.

Genotype PT (�C) PV(cP) MV(cP) FV(cP)

Chalque~no 76.8 a 2476 cd 1589 c 3970 dPepitilla 72.3 b 2960 a 2227 a 5266 aWPN 77.3 a 2229 d 1536 c 4451 bcWPB 76.2 a 2950 a 1735 b 4599 bYPN 75.9 a 2763 ab 1771 b 4551 bYPB 76.5 a 2597 bc 1557 c 4168 cd

a PT ¼ pasting temperature (initial gelatinization temperature); PV ¼ peak vis-cosity; MV ¼ minimum viscosity or holding strength; FV ¼ final viscosity.



tortillas made with WPN and WPB (White Population from theBajío) maize hybrids were harder (2.48 N) and had a higherextensibility values (10.6 mm). Moreover, processes of nixtamali-zation and tortilla-making caused oil losses of 12.1e48.9 g/100 g.The smallest losses and highest oil content in tortillas were found inthose made with YPN and YPB (Table 4). Losses are attributed tolipid hydrolysis in the alkaline solution, which favors lipid solubi-lization in the nejayote. Lipids can also react with calcium ionsforming unsaponifiable material that cannot be efficiently extrac-ted. Lipid content in tortillas is thus reduced significantly.

3.4. Pasting and rheological properties of masa

Among the genotypes assessed, significant differences werefound in masa pasting temperature and viscosity parameters(Table 5). Peak viscosity values were in the range of 2229e2960 cP,superior to those found in whole grain flours; the same pattern ofminimum and final viscosity was observed. These differences inviscosity values can be attributed to three aspects: 1) presence ofpericarp gums and saponified germ lipids that remain afterwashing the nixtamal and improve masa viscosity characteristics(Flores-Farías et al., 2000; Martínez-Bustos et al., 2001), 2) inter-action of calcium ions and starch, and 3) formation of amylo-seelipid complexes (Mondrag�on, Mendoza-Martínez, Bello-P�erez,& Pe~na, 2006). In this sense, it is clear that the masa from Pepi-tilla owes these viscosity values partly to the high percentage ofretained pericarp (49.4 g/100 g) (Table 4), while the lower viscosityvalues of masa from the other genotypes are due to lower retentionof pericarp and possibly to the formation of amyloseelipid com-plexes. These complexes, according to Mondrag�on et al. (2006),inhibit amylose leaching and starch granule swelling. This effectcan be observed in the viscoelasticity analysis (Fig. 2). From atechnological perspective, masa from genotypes with high values ofviscosity are more machinable, more tolerant to mixing and lesslikely to be brittle; this will, in the end, be reflected in good tortillatexture.

Fig. 2 shows the frequency sweep of the masas in which theirviscoelastic characteristics (G0 and G00) can be seen to be dependenton frequency since when frequency increases, both parametersincrease. For all the masa and at any frequency, elastic module G0

was always higher than viscous module G00. Similar behavior wasreported by Mendez-Montealvo et al. (2006) and Mondrag�on et al.(2006). According to the literature, this behavior (G0 > G00) is char-acteristic of starch gels. The highest G0 and G00 values weremeasured in the masa made from the genotype Pepitilla, while thelowest were found in YPB masa. These results indicate that theviscoelasticity of Pepitilla maize masa is greater than that of theother genotypes, whose masas are firmer, possibly owing to thepresence of more natural gum, since Pepitilla had a higher contentof retained pericarp (RP) (49.4 g/100 g), and to the low lipid


Fig. 2. Frequency sweep (0.1% strain) of masa from maize landraces and high oilcontent hybrids. (-) Pepitilla; (;) WPB; (:) WPN; (C) Chalque~no; (A) YPN; (*) YPB.Filled symbols G0; empty symbols G0 .

M.G. V�azquez-Carrillo et al. / LWT - Food Science and Technology xxx (2014) 1e6 5

content. The least elastic module and the least viscousmodulewerefor YPB hybrid, which had the lowest content of RP (36.5 g/100 g)and the highest content of lipids. According to Mondrag�on et al.(2006), the formation of amyloseelipid complexes can decreasethe viscoelasticity of the gel since they interrupt the associationbetween chains, resulting in a decrease in G0 and G00 and thereforesofter masas. This behavior is clear in our study: as the concen-tration of lipids in the masa increases, the values of G0 and G00

decrease. It is important to highlight that the masa made with theChalque~no landrace showed viscoelastic characteristics (G0, G00)similar to the masa made from HOC genotypes. This may be due tothe scarce natural gums in the masa rather than to the formation ofamyloseelipid complexes.

3.5. Tortilla pasting properties

In Table 6 it can be observed that peak, minimum and finalviscosities in tortillas decreased, relative to those observed in masa.This is because in making tortillas the masa was subjected to anadditional thermal process (baking), which increased the degree ofgelatinization of the starch granules. The highest viscosity valueswere found in the genotype Pepitilla; this means that it had thelargest amount of ungelatinized starch granules. Among the high-oil genotypes, no significant differences were found; WPN, how-ever, had the highest viscosity and it was the genotype with thelowest oil content in its tortillas. In this regard, Ar�ambula-Villa et al.(2001) found that in tortillas made from extruded flour peak

Table 6Pasting propertiesa,b of tortillas from maize landraces and high oil content hybrids.

Genotype PT (�C) PV(�C) MV(�C) FV(�C)

Chalque~no 78.69 a 1380 bc 1438 b 3062 bcPepitilla 77.48 b 2786 a 2155 a 5086 aWPN 77.38 b 1697 b 1470 b 3268 bWPB 74.49 d 1570 bc 1360 c 3067 bcYPN 76.92 b 1515 bc 1269 d 2970 bcYPB 75.57 b 1328 c 1131 e 2463 c

a PT ¼ pasting temperature (onset gelatinization temperature); PV ¼ peak vis-cosity; MV ¼ minimum viscosity or holding strength; FV ¼ final viscosity.



viscosity increased proportionally to the amount of lipids added.They attributed this proportional increase to a delayed effect of thestarch gelatinization process. In our study, a contrary effect wasobserved: an increase of lipid content in the tortilla caused adecrease in pasting temperature and a decrease in peak, minimumand final viscosity. Raphaelides and Georgiadis (2006) suggest thatdecreased viscosity is due to the formation of a layer of lipidsaround the starch granule, increasing its hydrophobicity andreducing its capacity for water absorption and its ability to swell.Additionally, amyloseelipid complexes that form during prepara-tion of the masa are present in high oil tortillas and, as mentionedabove, these amyloseelipid complexes inhibit swelling of thestarch granule. A negative correlation was found between mini-mum and final viscosity and oil content in the tortillas (r ¼ �0.73and r ¼ �0.66, p < 0.01), meaning that as the content of oil in-creases in the tortillas, the retrogradation phenomenon decreases,an indication that the tortillas with high oil content will remainsofter than those with low oil content because in the latter theretrogradation phenomenon occurs with greater intensity, as inPepitilla. This hypothesis was previously confirmed by V�azquez-Carrillo et al. (2014), who found that tortillas with high oil con-tent were softer and more flexible, recently made and duringstorage at 4 �C for up to 72 h, than those with low oil content madewith normal maize genotypes.

4. Conclusions

High oil maize genotypes had the hardest grains and the land-races had the softest. Pepitilla had the highest peak viscosity ingrain, masa and tortillas, reflected in greater water absorption andhigher masa and tortilla yield. The yellow maize genotypes (YPNand YPB) had the highest oil content in tortillas, which were softer(1.79 N) than those of the other genotypes. The increase in themasalipid content reduced the masa elasticity possibly due to thepresence of amyloseelipid complexes. The greater presence oflipids in tortillas was reflected in a decrease in peak, minimum andfinal viscosity causing a decrease in retrogradation, which in turn,keeps tortillas softer during storage.

References

AACC. (2000). Approved methods of analysis (10th ed.). Minnesota: AACCInternational.

Ar�ambula-Villa, G., Gonz�alez-Hern�andez, J., & Ordorica-Falomir, C. A. (2001).Physicochemical, structural and textural properties of tortillas from extrudedinstant corn flour supplemented with various types of corn lipids. Journal ofCereal Science, 33, 245e252.

Ar�ambula-Villa, G., Guti�errez-Arias, E., & Moreno-Martínez, E. (2007). Thermalproperties of maize masa and tortillas with different components from maizegrains, and additives. Journal of Food Engineering, 80, 55e60.

Flores-Farías, R., Martínez-Bustos, F., Salinas-Moreno, Y., Kil, C. Y., Gonz�alez, H. J., &Ríos, E. (2000). Physicochemical and rheological characteristics of commercialnixtamalized Mexican maize flours for tortillas. Journal of the Science of Foodand Agriculture, 80, 657e664.

Gonz�alez, A. U. (2009). El maíz y su conservaci�on. M�exico: Trillas.Lambert, R. J., Alexander, D. E., & Han, Z. J. (1998). A high oil pollinator enhancement

of kernel oil and effects on grain yields of maize hybrids. Agronomy Journal, 90,211e215.

Martínez-Bustos, F., Martínez-Flores, H. E., Sanmartin-Martínez, E., S�anchez-Sinencio, F., Chang, Y. K., Barrera-Arellano, D., et al. (2001). Effect of the com-ponents of maize on the quality of masa and tortillas during the traditionalnixtamalisation process. Journal of the Science of Food and Agriculture, 81,1455e1462.

M�endez, M. G., Solorza, F. J., Vel�azquez, V. M., G�omez, M. N., Paredes, L. O., &Bello, P. L. A. (2005). Chemical composition and calorimetric characterization ofhybrids and varieties of maize cultivated in M�exico. Agrociencia, 39, 267e274.

Mendez-Montealvo, G., S�anchez-Rivera, M. M., Paredes-L�opez, O., & Bello-P�erez, L. A. (2006). Thermal and rheological properties of nixtamalized maizestarch. International Journal of Biological Macromolecules, 40, 59e63.

M�enera-L�opez, I., Gayt�an-Martínez, M., Reyes-Vega, M. L., Morales-S�anchez, E., &Figueroa, J. D. C. (2013). Physico-chemical properties and quality assessment of


http://refhub.elsevier.com/S0023-6438(14)00474-5/sref1



























































corn flour processed by a continuous ohmic heating system and traditionalnixtamalization. CyTA-Tournal of Food, 11(1), 8e14.

Mondrag�on, M., Mendoza-Martínez, A. M., Bello-P�erez, L. A., & Pe~na, J. L. (2006).Viscoelastic behavior of nixtamalized maize starch gels. Carbohydrate Polymers,65, 314e320.

Narv�aez-Gonz�alez, D. E., Figueroa-C�ardenas, J. D., Taba, S., & Rinc�on, S. F. (2006).Kernel microstructure of Latin American races of maize and their thermal andrheological properties. Cereal Chemistry, 83, 605e610.

Raphaelides, S. N., & Georgiadis, N. (2006). Effects of fatty acids on rheologicalbehaviour of maize starch dispersions during heating. Carbohydrate Polymers,65, 81e92.

SAGARPA-Ministry of Agriculture, Livestock, Rural Development, Fisheries andFood. (2002). NMX-FF-034/1-SCFI-2002. Non industrialized food products forhuman consumption-Cereals-Part 1: White corn for alkaline process of corn tor-tillas and nixtamalized corn products-Specifications and test methods. M�exico D.F:General Department of Standards.

Sandhu, K. S., & Singh, N. (2007). Some properties of corn starches II: physico-chemical, gelatinization, retrogradation, pasting and gel textural properties.Food Chemistry, 101, 1499e1507.


SE-DGIB e Ministry of Economy-Department of Basic Industries. (2012). Analysis ofthe value chain corn-tortilla: Current status and factors of local competition.http://www.economia.gob.mx/files/comunidadnegocios/industria_comercio/informacionSectorial/20120411_analisis_cadena_valor_maiz-tortilla.pdfAccessed 20.11.13.

Takahashi, S., & Seib, P. A. (1988). Paste and gel properties of prime corn and wheatstarches with and without native lipids. Cereal Chemistry, 65, 474e483.

V�azquez-Carrillo, G., García-Lara, S., Salinas-Moreno, Y., Bergvinson, D. J., & Palacios-Rojas, N. (2011). Grain and tortilla quality in landraces and improved maizegrown in the highlands of Mexico. Plant Foods for Human Nutrition, 66,203e208.

V�azquez-Carrillo, M. G., Santiago-Ramos, D., Salinas-Moreno, Y., L�opez-Cruz, J.,Ybarra-Moncada, M. C., & Ortega-Corona, A. (2014). Oil content in maize (Zeamays L.) genotypes and its relationship with quality and texture of tortilla.Agrociencia, 48, 159e172.

Vidal-Quintanar, R. L., Love, J., & Johnson, L. A. (2001). Role of oil on physicalproperties of corn masa flours and sensory characteristics of corn tortilla.Journal of Food Processing and Preservation, 25, 1e14.


































http://www.economia.gob.mx/files/comunidadnegocios/industria_comercio/informacionSectorial/20120411_analisis_cadena_valor_maiz-tortilla.pdf

http://www.economia.gob.mx/files/comunidadnegocios/industria_comercio/informacionSectorial/20120411_analisis_cadena_valor_maiz-tortilla.pdf





















Documents

High oil content maize: Physical, thermal and rheological properties of grain, masa, and tortillas