Amaranth and quinoa in extruded corn snacks: Effect of storage temperature on lipid oxidation

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Amaranth and quinoa are pseudocereals cultivated in South America that could become attractive food alternatives in Europe due to their status as gluten-free. The aims of this investigation were to prepare corn-based snacks containing amaranth and quinoa using extrusion cooking, and to evaluate lipid stability of snacks exposed to different storage temperatures. Amaranth and quinoa grains were delivered from South America, and precooked cornmeal (polenta) was purchased from a local store. Grains were milled with a pin disc mill (flour particle size <500 μm). A co-rotating twin-screw extruder was used to obtain corn-based extrudates containing various concentrations of amaranth and quinoa flour (tested flours). Samples for analyses (content of tested flours, TF: 20, 35 and 50%) were collected under specific extrusion conditions (water content of mass: 14%; screw speed: 350 and 500 rpm; temperature of die: 140 and 150 °C). Analyses included determination of sectional expansion index (SEI), hardness and water content of extrudates (WCE). Formation of hexanal was evaluated from extrudates stored in sealed headspace vials at 20 and 40 °C in darkness using headspace gas chromatography at intervals during storage (0, 1, 3 and 5 weeks). Extrudates containing 20% TF presented significantly higher SEI (p<0.05) than those containing 35 and 50% TF. Hardness and WCE was generally higher in extrudates containing 35% TF than in those containing 20 and 50% TF. SEI was above 8 and hardness below 70 N/mm regardless of the TF. In general, extrudates containing quinoa presented lower hexanal production than extrudates containing amaranth in storage. Extrudates containing quinoa and exposed to 20 °C presented a stable hexanal production along time in contrast to those containing amaranth. At 40 °C, extrudates containing quinoa and amaranth showed a rapid increase in hexanal production after 1 week of storage. This study proved that it is possible to obtain expanded extrudates with relatively low hardness and containing up to 50% amaranth or quinoa. Extrudates containing amaranth appeared more sensitive to oxidation than those containing quinoa.
Originalspråkengelska
Titel på gästpublikationBook of proceedings : InsideFood Symposium
Antal sidor6
UtgivningsortLeuven
Utgivningsdatum2013
Sidor1-6
StatusPublicerad - 2013
MoE-publikationstypB3 Ej refererad artikel i konferenshandlingar
EvenemangInsideFood Symposium - Leuven, Belgien
Varaktighet: 9 apr 201312 apr 2013

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