Molecular weight and structure of water soluble (1→3), (1→4)-β-glucans affect pasting properties of oat flours.

Abstract

Seven experimental oat lines with high (5.9% to 7.2%), medium (5.3% to 5.5%), and low (4.4%) β-glucan concentrations were evaluated for the effects of β-glucan molecular weight (MW) and structure on viscosities of oat-flour slurries. The MW of β-glucans was determined by size-exclusion high-performance liquid chromatography. The structural features of β-glucans were measured by using fluorophore-assisted capillary-electrophoresis after complete hydrolysis with lichenase. The oat-slurry viscosities were measured on a Rapid Visco Analyser under 4 conditions: (1) without starch (amylolysis, removal of starch by α-amylase); (2) without β-glucan (removal of β-glucan by lichenase); (3) natural action of enzymes (autolysis, in sodium buffer); and (4) inhibition of enzymes (in silver nitrate solution). Excluding one line (regression outlier), significant correlations (P < 0.05) between peak MW of β-glucan and viscosities of oat slurries were obtained under inhibition. The ratio of degree of polymerization (DP) 3/DP4 negatively correlated with viscosity under amylolysis, autolysis, and inhibition (P < 0.05). The amount of DP ≥ 5 negatively correlated with pasting final viscosity after β-glucan removal by lichenase (P < 0.05). Positive correlations (P < 0.05) between the ratio of β-(1→4)/β-(1→3) linkages and viscosities under autolysis and inhibition were found. Overall, these findings demonstrated that the peak MW, ratio of DP3/DP4, amount of DP ≥ 5, and ratio of β-(1→4)/β-(1→3) linkages of β-glucans impacted pasting properties of oat-flour slurries.

• Authors: Yanjun Liu, Pamela J White
• Journal: Journal of food science (J Food Sci) 2011 Jan-Feb Vol. 76 Issue 1 Pg. C68-74 ISSN: 1750-3841 [Electronic] United States
• PMID: 21535656 (Publication Type: Comparative Study, Journal Article, Research Support, U.S. Gov't, Non-P.H.S.)

Chemical References

• Dietary Fiber
• Enzyme Inhibitors
• beta-Glucans
• beta-glucan, (1-3)(1-4)-
• Glycoside Hydrolases
• licheninase

Topics

• Avena (chemistry, genetics)
• Carbohydrate Conformation
• Chemical Phenomena
• Chromatography, Gel
• Chromatography, High Pressure Liquid
• Dietary Fiber (analysis, metabolism)
• Electrophoresis, Capillary
• Enzyme Inhibitors (pharmacology)
• Flour (analysis)
• Glycoside Hydrolases (antagonists & inhibitors, metabolism)
• Hydrolysis
• Kinetics
• Mechanical Phenomena
• Molecular Weight
• Seeds (chemistry)
• Solubility
• Species Specificity
• Viscosity
• beta-Glucans (chemistry, isolation & purification, metabolism)