Effect of Extrusion Process Parameters on the Quality of Buckwheat Flour Mixes

Abstract

Cereal Chem. 75(3):338-345A response surface analysis using a second-order central composite design was used to study the effect of extrusion process parameters on the extrudate quality of three blends containing buckwheat flour. The extrudates were prepared as three blends. Blend 1 was a 55:40:5 (w/w) mix of light buckwheat flour, wheat flour, and nonfat dry milk (NFDM). Blend 2 was a 40:55:5 mix of light buckwheat flour, corn meal, and NFDM. Blend 3 was a 30:60:10 mix of light buckwheat flour, corn meal, and NFDM. The blends were processed in a twin-screw extruder with factorial combinations of the parameters including: process temperatures of 95-150°C, dough moisture of 15-22%, and screw speeds of 260-390 rpm. The linear components alone significantly explained most of the variation of expansion index, bulk density, water absorption, and break-ing strength. The greatest amount of variability was explained by process temperature for blend 1. Dough moisture accounted for the greatest amount of variation for blends 2 and 3. Maximum predicted expansion index values and high water absorption percentages were obtained at low dough moisture levels. Dough moisture and process temperatures were the most important factors predicting bulk density. Sensory evaluation of texture, color, flavor, and general acceptability scores of selected samples ranked blend 3 > blend 2 > blend 1. The in vitro protein digestibility values ranked blend 1 > blend 2 > blend 3. An increase of up to 9.5% units in the protein digestibility values was observed when compared to the nonextruded raw blends.

Effect of Extrusion Conditions on Cassava/Soybean Extrudates

“…These observations confirm similar findings reported for starch-based extrudates obtained either using single or twin screw extrusion [47,48]. Dextrinization is well known as the predominant mechanism of starch degradation during low moisture extrusion [37]. Therefore, the decreasing trend of WSI with FM was expected and in agreement with previous reports [43,49].…”

“…WAI depends on the availability of hydrophilic groups which bind water molecules and the gel-forming capacity of the macromolecules involved [37]. Dispersion is observed to increase in proportion to the degree of starch damage due to gelatinization and extrusion-induced fragmentation, that is, molecular weight reduction of amylose and amylopectin molecules [38].…”

Effect of Operating Parameters on Physical Properties of Kodo Based Soy Fortified Ready to Eat Extruded Snacks

“…Water absorption index is referred to as measurement of the degree of starch gelatinization (OwusuAnsah et al, 1983a;Pinnavaia and Pizzirani, 1998). Water absorption has been generally attributed to the dispersion of starch in excess water and the dispersion is increased by degree of starch damage due to gelatinization and extrusion-induced fragmentation, that is, molecular weight reduction of amylose and amylopectin molecules (Rayas-Duarte et al, 1998) (Table 2).…”

Optimization of meat level and processing conditions for development of chicken meat noodles using response surface methodology

“…Water absorption has been generally attributed to the dispersion of starch in excess water, and the dispersion is increased by the degree of starch damage due to gelatinization and extrusioninduced fragmentation, that is, molecular weight reduction of amylose and amylopectin molecules (Rayas-Duarte et al 1998). Changes in WAI of chicken noodles were affected significantly by meat level, steaming time and drying time.…”