Sensory and Instrumental Analyses of Volatiles Generated during the Extrusion Cooking of Oat Flours

Abstract

Three batches of oats were extruded under four combinations of process temperature (150 or 180 degrees C) and process moisture (14. 5 and 18%). Two of the extrudates were evaluated by a sensory panel, and three were analyzed by GC-MS. Maillard reaction products, such as pyrazines, pyrroles, furans, and sulfur-containing compounds, were found in the most severely processed extrudates (high-temperature, low-moisture). These extrudates were also described by the assessors as having toasted cereal attributes. Lipid degradation products, such as alkanals, 2-alkenals, and 2, 4-alkadienals, were found at much higher levels in the extrudates of the oat flour that had been debranned. It contained lower protein and fiber levels than the others and showed increased lipase activity. Extrudates from these samples also had significantly lower levels of Maillard reaction products that correlated, in the sensory analysis, with terms such as stale oil and oatmeal. Linoleic acid was added to a fourth oat flour to simulate the result of increased lipase activity, and GC-MS analysis showed both an increase in lipid degradation products and a decrease in Maillard reaction products.

Sensory characteristics of wholegrain and bran-rich cereal foods – A review

“…These compounds are especially abundant in high-temperature, low-moisture extruded oats, and the products are described as roasted or toasted, caramelized and somewhat sweet, or nutty in flavour (Heydanek & McGorrin, 1986;Parker, Hassell, Mottram, & Guy, 2000;Klensporf & Jelén, 2008). In contrast, proteolytic reactions release peptides which are perceived as less appealing.…”

Optimization of process parameters for extrusion cooking of low amylose rice flour blended with seeded banana and carambola pomace for development of minerals and fiber rich breakfast cereal

“…Extruded products are extensively studied (Balasubramanian et al 2012;Eastman et al 2001;Parker et al 2000;Guha and Ali 2006) signifying wide acceptability. However, the characteristics of starch based extrudates depend on many factors, such as feed moisture and lipid content, additives and variables like screw speed, barrel temperature and type of extruder (Jin et al 1995;Suknark et al 1997;Singh et al 1998;Singh et al 2007).…”

Quality evaluation of millet-soy blended extrudates formulated through linear programming

“…They can be sweet or savory, light or substantial, and many even are endowed with attributes such as 'Healthy' or 'just for fun' (Desrumaux et al 1999). Advantages of extrusion cooking are exhaustively studied by many researchers (Camire et al 1990;Parker et al 2000;Eastman et al 2001). Increasing amount of time spent away from home has led to an increase in snacking (Euromonitor 2001) and now consumers see eating as something to be done while you do something else (Calder 2000).…”