Publication no. C-2001-1002-05R |  VIEW ARTICLE

Effect of Drying Treatment Conditions on Sensory Profile of Germinated Oat.

R.-L. Heiniö (1,2), K.-M. Oksman-Caldentey (1), K. Latva-Kala (1), P. Lehtinen (3), and K. Poutanen (1). (1) VTT Biotechnology, P.O. Box 1500, FIN-02044 VTT Finland. (2) Corresponding author. E-mail: <raija-liisa.heinio@vtt.fi> Phone: +358 9 456 5178. Fax: +358 9 455 2103. (3) Helsinki University of Technology, P.O. Box 1000, FIN-02015 TKK Finland. Cereal Chem. 78(6):707-714. Accepted June 6, 2001. Copyright 2001 American Association of Cereal Chemists, Inc.

Germination and subsequent drying of oat produced significantly different sensory profiles depending on processing parameters such as drying speed and temperature profile. The most salient sensory attributes for processed oat were roasted odor and flavor, sweet taste, intense odor, intense aftertaste, and hard, crisp, brittle texture (P < 0.05). High temperatures (>85ºC) were necessary to produce these sensory attributes, and quick drying after germination resulted in higher levels of intensity of favorable sensory attributes. The total amount of volatile compounds was higher in native (ungerminated) oat than in processed oat. During germination, and particularly during the drying treatment, the profile of volatile compounds changed. The most abundant volatile compounds responsible for odor were dimethyl sulfide, hexanal, pentanal, and isobutanal. The relative amount of dimethyl sulfide increased as a function of temperature in drying, whereas hexanal, pentanal, and isobutanal disappeared during heating, as did several other small ketones, alcohols, and esters. The germinated oat dried at high temperatures (65-93°C and 65-85°C) was perceived as being roasted, sweet, and nutty. Sensory and instrumental profile analyses of selected volatile compounds using partial least squares (PLS) regression techniques showed that these sensory attributes were clearly related to dimethyl sulfides and isobutanol. A moist and earthy odor was related to cymene, limonene, and isobutanal. Phenolic compounds significantly influenced oat flavor, whereas lipids had a negligible effect.