Structure and Functionality of Barley Starches

Abstract

Amylose contents of prime starches from nonwaxy and high‐amylose barley, determined by colorimetric method, were 24.6 and 48.7%, respectively, whereas waxy starch contained only a trace (0.04%) of amylose. There was little difference in isoamylase‐debranched amylopectin between nonwaxy and high‐amylose barley, whereas amylopectin from waxy barley had a significantly higher percentage of fraction with degree of polymerization < 15 (45%). The X‐ray diffraction pattern of waxy starch differed from nonwaxy and high‐amylose starches. Waxy starch had sharper peaks at 0.58, 0.51, 0.49, and 0.38 nm than nonwaxy and high‐amylose starches. The d‐spacing at 0.44 nm, characterizing the amylose‐lipids complex, was most evident for high‐amylose starch and was not observed in waxy starch. Differential scanning calorimetry (DSC) thermograms of prime starch from nonwaxy and high‐amylose barley exhibited two prominent transition peaks: the first was >60°C and corresponded to starch gelatinization; the second was >100°C and corresponded to the amylose‐lipid complex. Starch from waxy barley had only one endothermic gelatinization peak of amylopectin with an enthalpy value of 16.0 J/g. The retrogradation of gelatinized starch of three types of barley stored at 4°C showed that amylopectin recrystallization rates of nonwaxy and high‐amylose barley were comparable when recrystallization enthalpy was calculated based on the percentage of amylopectin. No amylopectin recrystallization peak was observed in waxy barley. Storage time had a strong influence on recrystallization of amylopectin. The enthalpy value for nonwaxy barley increased from 1.93 J/g after 24 hr of storage to 3.74 J/g after 120 hr. When gel was rescanned every 24 hr, a significant decrease in enthalpy was recorded. A highly statistically significant correlation (r = 0.991) between DSC values of retrograded starch of nonwaxy barley and gel hardness was obtained. The correlation between starch enthalpy value and gel hardness of starch concentrate indicates that gel texture is due mainly to its starch structure and functionality. The relationship between the properties of starch and starch concentrate may favor the application of barley starch concentrate without the necessity of using the wet fractionation process.

Physicochemical, thermal and rheological properties of starches isolated from malting barley varieties

“…Protein content of the analyzed starches isolated from malting barley varieties amounted from 0.50 (for BS8 sample) to 1.26 (for BS3 sample) g per 100 g of starch dry mass. These values were similar to these reported by Czuchajowska et al (1998) and Soares et al (2007). Slightly lower values of protein content of the barley starches were reported by Goering et al (1973) and Gao et al (2009).…”

“…Linear starch fraction content of the samples ranged between 19.6 and 25.2/100 g of starch dry mass, for BS2 and BS7 starch, respectively. These values were comparable with literature data concerning various kinds of barley starches (Bello-Perez et al 2010;Czuchajowska et al 1998;Gao et al 2009;Tang et al 2004;Yoshimoto et al 2002), however, much higher amylose content of the starch isolated from Brazilian malting barley variety was reported by Soares et al (2007). These authors claim that amylose content of starch is dependent on the conditions of the plant growing.…”

Extração de β-glucanas de cevada e caracterização parcial do amido residual

“…Esses valores são esperados para o teor de 18% de amilose aparente encontrado na amostra e estão de acordo com a literatura, que indica que, normalmente, quanto menor o teor da amilose, maior o poder de inchamento do amido (MACGREGOR & FINCHER, 1993;CZUCHAJOWSKA et al, 1998;SONG & JANE, 2000).…”

The Economic Potential of Brewer’s Spent Grain (BSG) as a Biomass Feedstock

“…In Table 2 5 [32]- [36], a composition was developed of other lignocelluloses for purposes of comparison to BSG, and validated these assumptions through the participant experts.…”