Starch characterization of different blue maize varieties

Abstract

Maize shows a significant genetic diversity, giving origin to a great number of varieties, hybrids, and genotypes. Recently, the pigmented corn varieties have received increased interest because of their anthocyanin contents. Although starch is the major component of the pigmented corn, only a few studies have been conducted on this constituent. The aim of this work was to evaluate the physicochemical properties and structural characteristics of starch isolated from six blue maize varieties grown in Mexico. The apparent amylose content ranged between 23.3 and 33.9%. The blue maize starches had an A-type X-ray diffraction pattern with similar crystallinity levels. Different gelatinization temperatures and enthalpy values were recorded, exhibiting different retrogradation tendencies (between 36.9 and 60.1%). The pasting parameters showed that the pasting temperature varied between 74.7 and 84.18C, the maximum peak viscosity between 83.2 and 111.2 RVU units, and the setback viscosity between 26 and 38 RVU units. Structural differences were observed in the degree of branching, molar mass, and gyration radius. In view of their different physicochemical and structural characteristics, each of the blue maize starch varieties studied could have their own specific applications.

Physicochemical, Structural, and Proteomic Analysis of Starch Granules from Maize Landraces of Northwest Mexico

“…The gelatinization enthalpy (Δ H G ) values ranged from 7.7 to 11.3 J/g (Chapalote and Blando de Sonora, respectively) and were similar to those observed by Li et al (1994) (8.2–13 J/g) in 35 tropical maize genotypes. The blue landrace Elotero de Sinaloa had a gelatinization enthalpy of 11.2 J/g, which falls within the range of values reported by De la Rosa‐Millán et al (2010) for six blue maize accessions of Mexico (9.6–12.2 J/g). Cooke and Gidley (1992) reported that gelatinization enthalpy is an indicator of starch crystallinity (double helices of amylopectin chains), and other authors reported that low amylopectin starches showed a low gelatinization enthalpy, which was associated with a lower degree of crystallinity (Gernat et al 1993; Matveev et al 2001).…”

“…The gelatinization and retrogradation parameters of the maize starches are shown in Table IV. The peak gelatinization temperature ( T pG ) varied from 71.9 (Reventador) to 73.0°C (Blando de Sonora); these results are within the range reported by De la Rosa‐Millán et al (2010) (67.0–73.8°C) in different varieties of Mexican blue maize. The highest T pG of Blando de Sonora starch corresponds with its highest crystallinity (Fig.…”

“…A higher accumulation of GBSSI was associated with the vitreous phenotype of quality protein maize (Salazar‐Salas et al 2014), and an increase in amylose content has been associated with more amorphous regions at the periphery of the starch granules, increasing their compressibility and compaction (Dombrink‐Kurtzman and Knutson 1997). Despite the diversity of maize landrace accessions in Northwest Mexico, there are only a few reports describing the physical and chemical properties of their grains (Mauricio‐Sanchez et al 2004) and even fewer studies addressing the starch physicochemical properties of these landraces (De la Rosa‐Millán et al 2010; Agama‐Acevedo et al 2011). Furthermore, these studies have only used one or two accessions, and none of them has related these properties with the expression of starch biosynthetic enzymes.…”

“…The average purity of the isolated starches was 92.3% (Table II); this value is smaller than those reported by Raguzzoni et al (2013) in six Brazilian maize landraces, which can be mainly attributed to differences in the purification methods used. The amylose content ranged from 20.1 to 28.8 g/100 g of starch (Blando de Sonora and Chapalote, respectively) (Table II); these values are within the range reported by De la Rosa‐Millán et al (2010) and Agama‐Acevedo et al (2011) (13–33.3 g/100 g of starch) for Mexican blue maize. Amylose content was positively correlated with grain hardness ( r = 0.88, P < 0.01), consistent with previous studies in maize reporting that amylose was always greater in hard endosperm samples than those with soft endosperm (Robutti et al 2000), which was associated with an increase in the amorphous regions and compressibility of starch granules in the hard endosperm (Dombrink‐Kurtzman and Knutson 1997).…”

Physical, Compositional, and Wet‐Milling Characteristics of Mexican Blue Maize (Zea mays L.) Landrace

“…The wet‐milling characteristics of GEM accessions (Singh et al 2001), GEM lines (Taboada‐Gaytan et al 2009), and experimental maize hybrids with exotic and nonexotic origin (Taboada‐Gaytan et al 2010a, 2010b) have also been reported. Efforts conducted to study Mexican blue maize landraces are currently focused on the evaluation of their anthocyanin content (Salinas‐Moreno et al 2012), antioxidant capacity (Del Pozo‐Insfran et al 2006), and more recently their structural, morphological, physicochemical, functional, and technological properties and starch biosynthesis enzymes (Agama‐Acevedo et al 2005, 2011; Utrilla‐Coello et al 2009; De la Rosa‐Millán et al 2010). However, little information is available regarding their wet‐milling properties.…”