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Amylose-lipid complex formation during extrusion cooking: effect of added lipid type and amylose level on corn-based puffed snacks



The effect of amylose-lipid complex formation during extrusion was studied with respect to expansion characteristics and oxidative stability of the extrudates. Full factorial design was adopted to investigate the effects of variables, amylose (two levels, 25% and 45%), types of lipid (coconut oil, fish oil and MaxEPA) and levels of lipid (1.5% and 3%), on amylose-lipid complex formation, expansion ratio, crispness, hardness and oxidative stability. Increased amylose content in feed mixture produced crispy extrudates with significantly higher (< 0.05) amylose-lipid complex formation, greater radial expansion, lower hardness and higher oxidative stability. Amylose-lipid complex formation and its complimentary effect, that is, oxidative stability were significantly higher in extrudates incorporated with coconut oil compared to those with fish oil or MaxEPA. However, better physical properties viz. radial expansion, crispness and lesser hardness were displayed by extrudates added with MaxEPA followed by those with fish oil. Between these two, fish oil-incorporated extrudates exhibited significantly higher oxidative stability compared to MaxEPA incorporated products. Thus, the study demonstrates the usefulness of amylose rich corn flour to make oxidatively stable fish oil-incorporated extrudates with better expansion characteristics.