Alpha-amylolysis of barley starch

Dissertation

Marianna Lauro

Research output: ThesisDissertationCollection of Articles

Abstract

The susceptibility of native barley starch granules and granules at different stages of gelatinization to a-amylolysis was studied by analyzing the amounts of solubilizing carbohydrates. The subsequent changes in the structure and properties of the insoluble residue were analyzed by various methods. The early stages of a-amylolysis of gelatinized barley and waxy barley starches were also followed. The gelation behavior of enzymatic hydrolysates of waxy barley starch with different molecular sizes was studied. In the a-amylolysis of both gelatinized and ungelatinized barley starch, the molecular weights of both amylose and amylopectin decreased. Amylopectin hydrolysis started between the clusters without shortening of the external chains. In the early stages of a-amylolysis of barley starch granules, lipid-complexed amylose was less accessible and concentrated in the insoluble granule residue and the solubilizing carbohydrates originated from free amylose and amylopectin. Amorphous and crystalline regions of granules solubilized equally and with more extensive hydrolysis, the granular structure and crystallinity were destroyed. Partial gelatinization changed the a-amylolysis pattern and the pinholes typical of a-amylase-treated large barley starch granules could not be seen. With regard to the leaching of lipid-complexed amylose, the a-amylolysis was similar to that of native barley starch granules. Additional lipid binding to starch during partial gelatinization stabilized the granular structure. Along with lipid complexed amylose, the small amount of free amylose remaining also concentrated in the residue, indicating that free amylose no longer existed as separate molecules but rather as part of otherwise complexed and thus insoluble molecules. Partial a-amylolysis increased the solubility of barley starch and changed the mechanism of swelling of the granules; granules became more transparent and no twisting was observed.
Original languageEnglish
QualificationDoctor Degree
Awarding Institution
  • Aalto University
Supervisors/Advisors
  • Poutanen, Kaisa, Supervisor
  • Forssell, Pirkko, Supervisor, External person
Award date1 Jun 2001
Place of PublicationEspoo
Publisher
Print ISBNs951-38-5844-8
Electronic ISBNs951-38-5845-6
Publication statusPublished - 2001
MoE publication typeG5 Doctoral dissertation (article)

Fingerprint

barley starch
amylose
granules
starch granules
amylopectin
gelatinization
lipids
solubilization
hydrolysis
carbohydrates
gelation
hydrolysates
amylases
shortenings
solubility
leaching
barley
starch
molecular weight

Keywords

  • barley
  • starch
  • amylopectin
  • amylose
  • solubilisation
  • enzymatic hydrolysis
  • alpha-amylolysis
  • composition
  • structure
  • gelation

Cite this

Lauro, M. (2001). Alpha-amylolysis of barley starch: Dissertation. Espoo: VTT Technical Research Centre of Finland.
Lauro, Marianna. / Alpha-amylolysis of barley starch : Dissertation. Espoo : VTT Technical Research Centre of Finland, 2001. 49 p.
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keywords = "barley, starch, amylopectin, amylose, solubilisation, enzymatic hydrolysis, alpha-amylolysis, composition, structure, gelation",
author = "Marianna Lauro",
year = "2001",
language = "English",
isbn = "951-38-5844-8",
series = "VTT Publications",
publisher = "VTT Technical Research Centre of Finland",
number = "433",
address = "Finland",
school = "Aalto University",

}

Lauro, M 2001, 'Alpha-amylolysis of barley starch: Dissertation', Doctor Degree, Aalto University, Espoo.

Alpha-amylolysis of barley starch : Dissertation. / Lauro, Marianna.

Espoo : VTT Technical Research Centre of Finland, 2001. 49 p.

Research output: ThesisDissertationCollection of Articles

TY - THES

T1 - Alpha-amylolysis of barley starch

T2 - Dissertation

AU - Lauro, Marianna

PY - 2001

Y1 - 2001

N2 - The susceptibility of native barley starch granules and granules at different stages of gelatinization to a-amylolysis was studied by analyzing the amounts of solubilizing carbohydrates. The subsequent changes in the structure and properties of the insoluble residue were analyzed by various methods. The early stages of a-amylolysis of gelatinized barley and waxy barley starches were also followed. The gelation behavior of enzymatic hydrolysates of waxy barley starch with different molecular sizes was studied. In the a-amylolysis of both gelatinized and ungelatinized barley starch, the molecular weights of both amylose and amylopectin decreased. Amylopectin hydrolysis started between the clusters without shortening of the external chains. In the early stages of a-amylolysis of barley starch granules, lipid-complexed amylose was less accessible and concentrated in the insoluble granule residue and the solubilizing carbohydrates originated from free amylose and amylopectin. Amorphous and crystalline regions of granules solubilized equally and with more extensive hydrolysis, the granular structure and crystallinity were destroyed. Partial gelatinization changed the a-amylolysis pattern and the pinholes typical of a-amylase-treated large barley starch granules could not be seen. With regard to the leaching of lipid-complexed amylose, the a-amylolysis was similar to that of native barley starch granules. Additional lipid binding to starch during partial gelatinization stabilized the granular structure. Along with lipid complexed amylose, the small amount of free amylose remaining also concentrated in the residue, indicating that free amylose no longer existed as separate molecules but rather as part of otherwise complexed and thus insoluble molecules. Partial a-amylolysis increased the solubility of barley starch and changed the mechanism of swelling of the granules; granules became more transparent and no twisting was observed.

AB - The susceptibility of native barley starch granules and granules at different stages of gelatinization to a-amylolysis was studied by analyzing the amounts of solubilizing carbohydrates. The subsequent changes in the structure and properties of the insoluble residue were analyzed by various methods. The early stages of a-amylolysis of gelatinized barley and waxy barley starches were also followed. The gelation behavior of enzymatic hydrolysates of waxy barley starch with different molecular sizes was studied. In the a-amylolysis of both gelatinized and ungelatinized barley starch, the molecular weights of both amylose and amylopectin decreased. Amylopectin hydrolysis started between the clusters without shortening of the external chains. In the early stages of a-amylolysis of barley starch granules, lipid-complexed amylose was less accessible and concentrated in the insoluble granule residue and the solubilizing carbohydrates originated from free amylose and amylopectin. Amorphous and crystalline regions of granules solubilized equally and with more extensive hydrolysis, the granular structure and crystallinity were destroyed. Partial gelatinization changed the a-amylolysis pattern and the pinholes typical of a-amylase-treated large barley starch granules could not be seen. With regard to the leaching of lipid-complexed amylose, the a-amylolysis was similar to that of native barley starch granules. Additional lipid binding to starch during partial gelatinization stabilized the granular structure. Along with lipid complexed amylose, the small amount of free amylose remaining also concentrated in the residue, indicating that free amylose no longer existed as separate molecules but rather as part of otherwise complexed and thus insoluble molecules. Partial a-amylolysis increased the solubility of barley starch and changed the mechanism of swelling of the granules; granules became more transparent and no twisting was observed.

KW - barley

KW - starch

KW - amylopectin

KW - amylose

KW - solubilisation

KW - enzymatic hydrolysis

KW - alpha-amylolysis

KW - composition

KW - structure

KW - gelation

M3 - Dissertation

SN - 951-38-5844-8

T3 - VTT Publications

PB - VTT Technical Research Centre of Finland

CY - Espoo

ER -

Lauro M. Alpha-amylolysis of barley starch: Dissertation. Espoo: VTT Technical Research Centre of Finland, 2001. 49 p.