Thermodynamic Properties of Barley Starches with Different Amylose Content

Yuryev, Vladimir P.; Kalistratova, E. N.; Soest, Jeroen G. J. van; Niemann, Claudia

doi:10.1002/(sici)1521-379x(199812)50:11/12<463::aid-star463>3.0.co;2-c

Cited by 30 publications

(21 citation statements)

References 11 publications

(25 reference statements)

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“…Values of van't Hoff enthalpy (ΔH VH ) were calculated as described earlier [18] using the following equation:…”

Section: Methodssupporting

confidence: 65%

“…Thermograms in Fig. 2 show that melting curves of starch samples in all the types of plant material display typical of native potato starch thermal transitions reflecting melting of crystalline lamellae of amylopec tin [18]. The graphs also show that, in starch samples isolated from the tubers of rolB and WT plants, the melting curves were rather symmetric relative the melting peak.…”

Section: Methodsmentioning

confidence: 99%

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Agrobacterial rol genes modify thermodynamic and structural properties of starch in microtubers of transgenic potato

Aksenova

Wasserman

Сергеева

et al. 2010

Russ J Plant Physiol

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INTRODUCTIONTuber formation in potato is regulated by numerous external and internal factors with phytohormones being of special importance [1]. In order to investigate the hormonal control over tuber formation, some researchers used transformed potato plants expressing rolB and rolC genes of Agrobacterium rhizogenes [2]. Biochemical mechanism of the operation of rol trans genes remains debatable; however, it was shown that their role in higher plants resembles to the effect of phytohormones: auxins in case rolB and cytokinins in case rolC [3]. It is assumed that hormone like effect of rol genes may be related to their influence on the metabolism of auxins and cytokinins or to the changes in plant cell sensitivity to these phytohormones [3]. It was also shown that the intensity of the effect of rol genes on morphogenesis of potato plants greatly depends on the used promoter governing organospec ificity of gene expression [4].It order to investigate the effect of genes rolB and rolC on tuber formation, we used B33 class I patatin promoter, which ensured preferred expression of B33::rolC and B33::rolB in growing potato tubers [5]. These experiments showed that transgenes induced numerous morphological changes accompanied by changes in the activity of some enzymes of carbohy drate metabolism, the content of soluble sugars [6], and the number and size of starch granules [7]. The obtained data suggested that transgenes rolB and rolC might also modify qualitative characteristics of storage starch, which by volume and biological role is the Abstract-Wild type (WT) plants of potato (Solanum tuberosum L.) and their transgenic forms carrying agro bacterial genes rolB or rolC under the control of B33 class I patatin promoter were cultured in vitro on MS medium with 2% sucrose in a controlled climate chamber at 16 h illumination and 22°C. These plants were used as a source of single node stem cuttings, which were cultured in darkness on the same medium supple mented with 8% sucrose. The tubers formed on them were used for determination of the structure of native starch using the methods of differential scanning microcalorimetry (DSC), X ray scattering, and scanning electron microscopy. It was found that, in starch from the tubers of rolB plants, the temperature of crystalline lamella melting was lower and their thickness was less than in WT potato. In tubers of rolC plants, starch dif fered from starch in WT plants by a higher melting temperature, considerably reduced melting enthalpy, and a greater thickness of crystalline lamellae. Deconvolution of DSC thermogram makes it possible to interpret the melting of starch from the tubers of rolC plants as the melting of two independent crystalline structures with melting temperatures of 65.0 and 69.8°C. Electron microscopic examination confirmed the earlier obtained data indicating that, in the tubers of rolC plants, starch granules are smaller and in the tubers of rolB plants larger than in WT plants. Possible ways of influence of rol transgenes on structural properties of star...

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“…Values of van't Hoff enthalpy (ΔH VH ) were calculated as described earlier [18] using the following equation:…”

Section: Methodssupporting

confidence: 65%

Section: Methodsmentioning

confidence: 99%

Agrobacterial rol genes modify thermodynamic and structural properties of starch in microtubers of transgenic potato

Aksenova

Wasserman

Сергеева

et al. 2010

Russ J Plant Physiol

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“…One of the most common methods, differential scanning calorimetry (DSC) measures the temperature at which starch crystallites melt 7,38 . Results using this technique indicate that waxy and high amylose barley starches have higher gelatinisation temperatures than does normal barley starch 33 .…”

Section: -2863(9'8-32mentioning

confidence: 99%

“…The high amylose starch had the highest gelatinisation temperature but it was only slightly higher than that of the waxy starch. Waxy barley starches had higher gelatinisation enthalpies (ÏH amylopectin) than the other starches but this may just be a reflection of the increased amylopectin content of the starch granules, and hence of the crystallinity of the waxy starch granules 32,38 . It would be predicted from these results that normal barley starch (i.e.…”

Section: )79087 %2( (-7'977-32mentioning

confidence: 99%

Gelatinisation Characteristics and Enzyme Susceptibility of Different Types of Barley Starch in the Temperature Range 48-72°C1

MacGregor

Bazin

Izydorczyk

2002

Journal of the Institute of Brewing

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The gelatinisation temperatures, pasting characteristics and enzymic susceptibilities in the temperature range 48-72°C of normal, high amylose, low amylose and zero amylose barley starches were determined. Normal starches had the lowest gelatinisation temperatures, but low and zero amylose starches had the lowest pasting temperatures. Normal starches were the most readily soluble in water at 48-60°C in the presence of a mixture of α-amylase, β-amylase and limit dextrinase and were most readily broken down to reducing sugars by these enzymes. High amylose starch was the most resistant to enzymic hydrolysis in the temperature range 48-72°C and, hence, produced the lowest level of reducing sugars.Key words: Barley, enzymic hydrolysis, gelatinisation, high amylose, pasting, starch, waxy.-2863(9'8-32The rapid and efficient conversion of starch to fermentable carbohydrates during brewing is dependent on a number of parameters including the level of starch degrading enzymes in the malt, the gelatinisation temperature of the starch and the actual temperature program of the mash. Starch hydrolysis is carried out by a number of malt enzymes working together. These include α-amylase, β-amylase, limit dextrinase and α-glucosidase 20,21 . Although α-amylase is able to hydrolyse intact starch granules, the rate of hydrolysis is very slow compared to that of solubilised starch 27,29 . Effective hydrolysis by α-amylase, therefore, occurs only after the starch has been solubilised (or gelatinised). When this has occurred, the enzyme rapidly degrades the starch components through random hydrolysis with concomitant reduction in the viscosity of the starch solution and formation of degradation products 22 that are substrates for β-amylase action. It is this action of β-amylase that is largely responsible for the conversion of starch to the major fermentable carbohydrates, glucose, maltose and maltriose 25 . β-Amylase, however, is relatively heat labile and rapidly loses activity 28 when mashing temperatures rise over 62.5°C. It is essential, therefore, that malt starch is gelatinised at or below this temperature to permit β-amylase to complete its action before losing a significant amount of activity through heat inactivation.The preferred substrates for limit dextrinase are the branched dextrins formed from starch by the combined action of α-and β-amylases 21 . Limit dextrinase appears to have only limited action during mashing, however 10 . This is caused, probably, through inhibition by low molecular weight inhibitors in the malt 17 rather than by excessive lability at mashing temperatures 28 . α-Glucosidase may play a role during mashing by hydrolysing small maltodexrins to glucose but the importance of α-glucosidase action remains unclear 31 .Several methods have been used to measure the gelatinisation (solubilisation) temperatures of starch granules but each tends to measure a different aspect of this complex phenomenon 2,34 and so not all methods give the same result. One of the most common methods, differential scanning cal...

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“…These changes in starch structure, known as retrogradation, decrease the eating quality of starch-based products 1,10 . The amylose content greatly influences the physicochemical properties of starch, such as gelatinization, retrogradation, and gelation 3,7,17,27 . Amylose synthesis depends mainly on the waxy protein, granule-bound starch synthase (GBSS) 4,22 .…”

Section: Introductionmentioning

confidence: 99%

Effect of Wheat Starch Characteristics on the Gelatinization, Retrogradation, and Gelation Properties

Sasaki

2005

JARQ

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The objective of this study was to clarify the relationship between amylose content and the gelatinization, retrogradation, and gelation properties of starch using wheat starches differing in amylose content. Starches were prepared by reciprocal crossing between waxy and non-waxy wheat, and mixing waxy and non-waxy wheat starch. Gelatinization temperature and endothermic enthalpy measured by differential scanning calorimetry correlated negatively with amylose content. Mixed starches showed significantly lower gelatinization onset and peak temperature than F 1 starches with the same amylose content. Rapid Visco Analyser measurement showed that F 1 starches had a higher peak viscosity than waxy and non-waxy wheat starches, and mixed starches had characteristic profiles with two low peaks. The rheological properties of 30% and 40% starch gels were measured using mixed starches with an amylose content of 5, 10, 18, 20, 23, and 25%. The slight difference in amylose content contributed greatly to the elastic component in starches forming a gel network. For 40% starch gels, mixed starch with lower amylose rapidly developed rigidity and had a higher rate constant of starch retrogradation. The proportion of waxy starch in the mixture played a major role in starch gel properties. Some of the gelatinization and gelation properties differed between mixed starch and simple starch isolated from cultivars, even though they have similar amylose content.

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Thermodynamic Properties of Barley Starches with Different Amylose Content

Cited by 30 publications

References 11 publications

Agrobacterial rol genes modify thermodynamic and structural properties of starch in microtubers of transgenic potato

Agrobacterial rol genes modify thermodynamic and structural properties of starch in microtubers of transgenic potato

Gelatinisation Characteristics and Enzyme Susceptibility of Different Types of Barley Starch in the Temperature Range 48-72°C1

Effect of Wheat Starch Characteristics on the Gelatinization, Retrogradation, and Gelation Properties

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