Effects of popping and extrusion processes on some hydration properties of amaranth

Abstract

-The effects of popping and extrusion processes on some of the hydration properties of Amarantus cruentus, which had already been degermed and dehulled, are discussed. Response surface methodology was used to analyse the effect of process variables (temperature and moisture) on hydration properties, evaluated by water solubility (S) and by amylographic retrogradation (R) . Results show that precooked flours obtained by popping have a very high suspension consistency with low or intermediate S, while those obtained by extrusion have very high S but a much lower suspension consistency. The high S values for extruded samples are even higher than those for extruded waxy types of cereals. The effects of the variables on each response depend on each case. S increases as temperature (T) and moisture (M) increase in both processes, although in extrusion, a maximum value was observed at 200 ºC and about 15% M. On the other hand, an inverse variable effect is observed for R; a minimum value is observed with extruded samples at about 14% M and for the whole T range, while a typical saddle-shaped surface is obtained for popped samples, with maximum values found at about 14 % and 18 % M for the two extreme T values, the highest and lowest, respectively. Another interesting effect is that the S-R pair values corresponding to popped samples do not fit the correlation between S and R, normally found with extruded samples. We can conclude that with the application of both processes it is possible to obtain precooked flours that have a wide range of hydration properties.

Amaranth starch-rich fraction properties modified by extrusion and fluidized bed heating

“…EH samples show the typical inverse relationship between retrogradation consistency and solubility found for extruded starchy materials (Gonza´lez et al, 1987(Gonza´lez et al, , 2002b, but the variability of amylographic consistency of amaranth starch samples is narrower than that of corn. This is attributable to the corn strong endosperm (Gonza´lez, Torres, De Greef, Tosi, & Re´, 2002a). FBH produces higher RC values than the untreated sample; such higher RC values were obtained at the lowest M. However, the damage degree caused to the starch granular structure for FBH at 200 1C and 200 g/kg wb moisture would be enough to give lower peak and retrogradation consistencies than those of the untreated sample.…”

Nutritional Components of Amaranth Seeds and Vegetables: A Review on Composition, Properties, and Uses

“…Thus, a high‐starch fraction (about 79% starch), which is constituted by the entire amaranth grain endosperm, or the degermed and dehulled grain together with the high‐protein fraction, were obtained by differential milling (González and others ). A solid character at low temperature, with high consistency when cooked, and low water solubility make amaranth high‐starch flours suitable for industrial applications; precooked flours were produced by popping and extrusion processes applied to the starchy fraction of A. cruentus (González and others ). A partial loss of starch crystalline structure was observed after heating at 190, 200, and 210 °C but most of their granular integrity was preserved, and as temperature and moisture increased, loss of crystalline structure and degree of gelatinization also increased (González and others ).…”

Soaking and extrusion effects on physicochemical parameters, phytic acid, nutrient content and mineral bio-accessibility of whole rice grain

“…This process provides high versatility of operations, such as mixing, cooking, drying and partial texturing. It is also beneficial from the standpoint of the use of energy, manpower and space required for installation (González et al, 2002b). Its use reduces the cost of post-extrusion drying and guarantees an improved shelf-life of the product without the need for cooling or refrigeration and produce unique product shapes with high quality.…”