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Influence of Heat Pretreatments of Oat Grain on the Viscosity of Flour Slurries
Author(s) -
Doehlert Douglas C,
Zhang Decai,
Moore Wayne R
Publication year - 1997
Publication title -
journal of the science of food and agriculture
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.782
H-Index - 142
eISSN - 1097-0010
pISSN - 0022-5142
DOI - 10.1002/(sici)1097-0010(199705)74:1<125::aid-jsfa782>3.0.co;2-s
Subject(s) - slurry , food science , steaming , chemistry , viscosity , roasting , raw material , materials science , organic chemistry , composite material
Heat treatment of oat grain had significant effects on the viscosity of flour slurries. Steamed oats produced highly viscous flour slurries, whose viscosity increased with time, whereas the viscosity of flour slurries produced from raw or roasted (104°C for 120 min) oats was much lower and degraded rapidly. Slurry viscosity was correlated with (1→3), (1→4)‐β‐ D ‐glucan concentration in the flours and treatment of slurries with lichinase lowered viscosity significantly. Effects of steaming were partially reversed by roasting treatment and vice versa. Mixtures of equal amounts of raw and steamed flour resulted in slurries more viscous than either flour alone, but that viscosity degraded after 3 h to less than the mean viscosity of the steamed and raw controls. Water‐soluble extracts from steamed flour had about twice the viscosity of raw or roasted flour extracts, but contained only 80% of the (1→3), (1→4)‐β‐ D ‐glucan present in those extracts. Molecular weight analysis of soluble carbohydrates from raw, roasted and steamed soluble extracts indicated the molecular weight of β‐glucans in these extracts was similar. However, if extracts were made from slurries that had incubated for 3 h, extensive degradation of β‐glucans was evident in raw and roasted samples. It is likely that enzymic degradation of (1→3),(1→4)‐β‐ D ‐glucans is responsible for much of the decreased raw and roasted flour slurry viscosity over extended time periods, but different heat treatments appear to also affect (1→3), (1→4)‐β‐ D ‐glucan polymer interaction. © 1997 SCI.