Effects of lipids, heating and enzymatic treatment on starches: Dissertation

Salem Sassi Shamekh

Research output: ThesisDissertation

Abstract

The effects of heat treatment on oat and barley starch water dispersions were investigated. As compared with barley starch, the granules from oat starch were more degraded, but the fractionation patterns of both starches were not significantly different. Microscopic examination indicated that no evidence of amylopectin fragments was observed in the liquid fraction after starch dispersions were treated at 95°C even though chemical analysis demonstrated the solubility of both starch polymers. True solubility of oat starch was lower than that of barley starch, but the difference disappeared after removing the lipids from oat starch. By applying sequential centrifugation for starch dispersions, treated above 90°C, a fraction rich in an amylose-lipid complex could be produced. Studies on crystallisation of starch gels were performed. The crystallisation rate of a gel prepared from oat starch was lower than those prepared from other cereal starches (barley and wheat). The effects of polar lipids separated from oats (oat lecithin) on crystallisation of wheat starch gel were investigated and compared with soya lecithin. Furthermore, the behaviour of polar lipids in the starch gel was compared with their effect on bread staling. Even though oat lecithin hydrolysate affected the crystallisation rate positively, soya lecithin hydrolysate was more effective both in gel as well as in bread. The ability of esterases to hydrolyse lipids of barley starch at temperatures close to gelatinisation and of the gelatinised barley starch was examined. The extent of lipid hydrolysis of starch granules was only about 20%, but almost all of the lipids of the gelatinised starch were hydrolysed at 40°C. The effect of freeze-drying on a-amylolysis of potato starch was also investigated, and was observed to greatly enhance the enzyme accessibility of the granules. The film formation property of hydrolysates prepared from potato starch was elucidated. Higher solids could be used in the film process due to a decrease in the molecular weight, and, after removing the water-soluble carbohydrates from the starch hydrolysates, good quality films were produced.
Original languageEnglish
QualificationDoctor Degree
Awarding Institution
  • Aalto University
Supervisors/Advisors
  • Poutanen, Kaisa, Supervisor
  • Forssell, Pirkko, Supervisor, External person
Award date15 Mar 2002
Place of PublicationEspoo
Publisher
Print ISBNs951-38-5975-4
Electronic ISBNs951-38-5976-2
Publication statusPublished - 2002
MoE publication typeG5 Doctoral dissertation (article)

Fingerprint

barley starch
oat starch
enzymatic treatment
starch
heat
crystallization
hydrolysates
phosphatidylcholines
lipids
starch gels
films (materials)
oats
wheat starch
potato starch
starch granules
breads
solubility
gels
amylopectin
freeze drying

Keywords

  • oat
  • barley
  • wheat
  • potato
  • starch
  • amylopectins
  • amylose
  • lipids
  • solubility
  • gels
  • films
  • lecithins
  • enzymatic hydrolysis

Cite this

Shamekh, S. S. (2002). Effects of lipids, heating and enzymatic treatment on starches: Dissertation. Espoo: VTT Technical Research Centre of Finland.
Shamekh, Salem Sassi. / Effects of lipids, heating and enzymatic treatment on starches : Dissertation. Espoo : VTT Technical Research Centre of Finland, 2002. 47 p.
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abstract = "The effects of heat treatment on oat and barley starch water dispersions were investigated. As compared with barley starch, the granules from oat starch were more degraded, but the fractionation patterns of both starches were not significantly different. Microscopic examination indicated that no evidence of amylopectin fragments was observed in the liquid fraction after starch dispersions were treated at 95°C even though chemical analysis demonstrated the solubility of both starch polymers. True solubility of oat starch was lower than that of barley starch, but the difference disappeared after removing the lipids from oat starch. By applying sequential centrifugation for starch dispersions, treated above 90°C, a fraction rich in an amylose-lipid complex could be produced. Studies on crystallisation of starch gels were performed. The crystallisation rate of a gel prepared from oat starch was lower than those prepared from other cereal starches (barley and wheat). The effects of polar lipids separated from oats (oat lecithin) on crystallisation of wheat starch gel were investigated and compared with soya lecithin. Furthermore, the behaviour of polar lipids in the starch gel was compared with their effect on bread staling. Even though oat lecithin hydrolysate affected the crystallisation rate positively, soya lecithin hydrolysate was more effective both in gel as well as in bread. The ability of esterases to hydrolyse lipids of barley starch at temperatures close to gelatinisation and of the gelatinised barley starch was examined. The extent of lipid hydrolysis of starch granules was only about 20{\%}, but almost all of the lipids of the gelatinised starch were hydrolysed at 40°C. The effect of freeze-drying on a-amylolysis of potato starch was also investigated, and was observed to greatly enhance the enzyme accessibility of the granules. The film formation property of hydrolysates prepared from potato starch was elucidated. Higher solids could be used in the film process due to a decrease in the molecular weight, and, after removing the water-soluble carbohydrates from the starch hydrolysates, good quality films were produced.",
keywords = "oat, barley, wheat, potato, starch, amylopectins, amylose, lipids, solubility, gels, films, lecithins, enzymatic hydrolysis",
author = "Shamekh, {Salem Sassi}",
year = "2002",
language = "English",
isbn = "951-38-5975-4",
series = "VTT Publications",
publisher = "VTT Technical Research Centre of Finland",
number = "460",
address = "Finland",
school = "Aalto University",

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Shamekh, SS 2002, 'Effects of lipids, heating and enzymatic treatment on starches: Dissertation', Doctor Degree, Aalto University, Espoo.

Effects of lipids, heating and enzymatic treatment on starches : Dissertation. / Shamekh, Salem Sassi.

Espoo : VTT Technical Research Centre of Finland, 2002. 47 p.

Research output: ThesisDissertation

TY - THES

T1 - Effects of lipids, heating and enzymatic treatment on starches

T2 - Dissertation

AU - Shamekh, Salem Sassi

PY - 2002

Y1 - 2002

N2 - The effects of heat treatment on oat and barley starch water dispersions were investigated. As compared with barley starch, the granules from oat starch were more degraded, but the fractionation patterns of both starches were not significantly different. Microscopic examination indicated that no evidence of amylopectin fragments was observed in the liquid fraction after starch dispersions were treated at 95°C even though chemical analysis demonstrated the solubility of both starch polymers. True solubility of oat starch was lower than that of barley starch, but the difference disappeared after removing the lipids from oat starch. By applying sequential centrifugation for starch dispersions, treated above 90°C, a fraction rich in an amylose-lipid complex could be produced. Studies on crystallisation of starch gels were performed. The crystallisation rate of a gel prepared from oat starch was lower than those prepared from other cereal starches (barley and wheat). The effects of polar lipids separated from oats (oat lecithin) on crystallisation of wheat starch gel were investigated and compared with soya lecithin. Furthermore, the behaviour of polar lipids in the starch gel was compared with their effect on bread staling. Even though oat lecithin hydrolysate affected the crystallisation rate positively, soya lecithin hydrolysate was more effective both in gel as well as in bread. The ability of esterases to hydrolyse lipids of barley starch at temperatures close to gelatinisation and of the gelatinised barley starch was examined. The extent of lipid hydrolysis of starch granules was only about 20%, but almost all of the lipids of the gelatinised starch were hydrolysed at 40°C. The effect of freeze-drying on a-amylolysis of potato starch was also investigated, and was observed to greatly enhance the enzyme accessibility of the granules. The film formation property of hydrolysates prepared from potato starch was elucidated. Higher solids could be used in the film process due to a decrease in the molecular weight, and, after removing the water-soluble carbohydrates from the starch hydrolysates, good quality films were produced.

AB - The effects of heat treatment on oat and barley starch water dispersions were investigated. As compared with barley starch, the granules from oat starch were more degraded, but the fractionation patterns of both starches were not significantly different. Microscopic examination indicated that no evidence of amylopectin fragments was observed in the liquid fraction after starch dispersions were treated at 95°C even though chemical analysis demonstrated the solubility of both starch polymers. True solubility of oat starch was lower than that of barley starch, but the difference disappeared after removing the lipids from oat starch. By applying sequential centrifugation for starch dispersions, treated above 90°C, a fraction rich in an amylose-lipid complex could be produced. Studies on crystallisation of starch gels were performed. The crystallisation rate of a gel prepared from oat starch was lower than those prepared from other cereal starches (barley and wheat). The effects of polar lipids separated from oats (oat lecithin) on crystallisation of wheat starch gel were investigated and compared with soya lecithin. Furthermore, the behaviour of polar lipids in the starch gel was compared with their effect on bread staling. Even though oat lecithin hydrolysate affected the crystallisation rate positively, soya lecithin hydrolysate was more effective both in gel as well as in bread. The ability of esterases to hydrolyse lipids of barley starch at temperatures close to gelatinisation and of the gelatinised barley starch was examined. The extent of lipid hydrolysis of starch granules was only about 20%, but almost all of the lipids of the gelatinised starch were hydrolysed at 40°C. The effect of freeze-drying on a-amylolysis of potato starch was also investigated, and was observed to greatly enhance the enzyme accessibility of the granules. The film formation property of hydrolysates prepared from potato starch was elucidated. Higher solids could be used in the film process due to a decrease in the molecular weight, and, after removing the water-soluble carbohydrates from the starch hydrolysates, good quality films were produced.

KW - oat

KW - barley

KW - wheat

KW - potato

KW - starch

KW - amylopectins

KW - amylose

KW - lipids

KW - solubility

KW - gels

KW - films

KW - lecithins

KW - enzymatic hydrolysis

M3 - Dissertation

SN - 951-38-5975-4

T3 - VTT Publications

PB - VTT Technical Research Centre of Finland

CY - Espoo

ER -

Shamekh SS. Effects of lipids, heating and enzymatic treatment on starches: Dissertation. Espoo: VTT Technical Research Centre of Finland, 2002. 47 p.