Mehmet Tulbek

Acceptability and characterization of extruded pinto, navy and black beans

BACKGROUND Consumption of dry beans has been relatively flat over the last decade. Creating new bean products may increase the consumption of beans and allow more consumers to obtain the health benefits of beans. In this study, pinto, navy and black beans were milled and the resulting flours extruded into puffs. Unflavored extruded puffs were evaluated by untrained panelists using a hedonic scale for appearance, flavor, texture and overall acceptability. The compositions of raw flours and extrudates were characterized. RESULTS Sensory results indicated that all beans met or exceeded the minimum requirement for acceptability. Overall acceptability of navy and pinto beans was not significantly different, while acceptability of black bean puffs was significantly lower. Total protein (198-217 g kg(-1)) in extrudates was significantly different among the three beans. Total starch ranged from 398 to 406 g kg(-1) and was not significantly different. Resistant starch, total extractable lipid and raffinose contents were significantly reduced by extrusion. Extrusion did not affect crude fiber and phytic acid contents. CONCLUSION The minimal effects on protein and fiber contents, the significant reduction in raffinose content and the acceptability of the unflavored extruded puffs support using various bean flours as ingredients in extruded puffed products.

Effects of Extruder Screw Speeds on Physical Properties and In Vitro Starch Hydrolysis of Precooked Pinto, Navy, Red, and Black Bean Extrudates

ABSTRACT Precooked pinto, navy, red, and black bean flours were extruded at different screw speeds (320, 380, and 440 rpm) with a twin-screw extruder. Effect of speed on physical properties and in vitro starch hydrolysis was investigated. Increasing screw speeds reduced water activity, expansion index, and texture. Extrudates could not be obtained from pinto bean flour at 440 rpm because of the high shear effect. Water absorption index and water solubility index were not significantly affected by screw speed but were significantly higher than for unextruded precooked flour. A significant change in color was observed in navy beans, characterized by increasing b values on the Hunter color scale. Resistant starch ranged from 3.65 to 4.83% db and was not significantly affected by screw speed. Glycemic index of all extrudates was high, ranging from 81.3 to 86.9.

Effects of Steam, Moisture, and Screw Speed on Physical Properties of DDGS-Based Extrudates

ABSTRACT A fractional factorial design with a replicated central composite point was used to investigate the effects of extrusion processing on physical properties of distillers dried grains with solubles (DDGS) based aquafeeds using a twin-screw extruder. Extrusion cooking trials were performed with a nutritionally balanced ingredient blend for Nile tilapia, with two levels of screw speed (350 and 450 rpm), two levels of extruder water (0.236 and 0.302 kg/min), and two levels of conditioner steam (0.1 and 0.15 kg/min). The central point was 400 rpm screw speed, 0.271 kg/min extruder water, and 0.12 kg/min conditioner steam. Effects of these processing conditions on extrudate characteristics were extensively analyzed and included moisture content, water activity, thermal properties, expansion ratio, unit density, bulk density, color, water stability, sinking velocity, water absorption and solubility indices, and pellet durability index. Increasing the extruder water and conditioner steam resulted in a 5.3...

Physicochemical Properties of Flaxseed Fortified Extruded Bean Snack

Milled flaxseed was incorporated (0–20%) into a combination of bean-corn flours and extruded in a twin screw extruder using corn curl method. Physicochemical parameters such as water activity, color, expansion ratio, bulk density, lipid content, and peroxide values of extruded snack were analyzed. Scanning electron micrographs were taken. Peroxide values and propanal contents were measured over four months of storage. Rancidity scores of extruded snack were measured using a trained panel. As expected, omega-3 fatty acids and bulk density increased with increasing flaxseed fortification levels. Extrudates with more flaxseed had decreased lightness values and expansion ratios. However, only the 15 and 20% flaxseed containing extrudates had expansion ratios that were significantly (P ≤ 0.05) different from the control. In general, no significant difference (P > 0.05) in water activity values was observed in the flaxseed fortified extrudates, except in the navy-corn based extrudates. Peroxide values increased with increased flaxseed levels and over a storage period. However, propanal values did not change significantly in the 5–10% flaxseed fortified extrudates but increased in extrudates with higher levels of flaxseed. Rancidity scores were correlated with peroxide values and did not increase significantly during storage under nitrogen flushed conditions.

Effects of Conditioner Steam, Extruder Water and Screw Speed on Physical Properties of DDGS-Based Extrudates in Twin-Screw Extrusion

A fractional factorial design with a replicated central composite point was used to investigate the effects of extrusion processing on physical properties of DDGS–based aquafeeds using a twin screw extruder. Extrusion cooking trials were performed using an ingredient blend for Nile tilapia, with 2 levels of screw speed (350 and 450 rpm), 2 levels of extruder water (0.236 and 0.302 kg/min) and 2 levels of conditioner steam (0.1 and 0.15 kg/min). The central point was 400 rpm screw speed, 0.271 kg/min extruder water, and 0.12 kg/min conditioner steam. Effects of these processing conditions on extrudate characteristics were extensively analyzed, and included moisture content, water activity, thermal properties, expansion ratio, unit density, bulk density, color, water stability, sinking velocity, water absorption and solubility indices and pellet durability index. Increasing the screw speed from 350 to 400 rpm resulted in a decrease in mass flow rate by 5.3%; while increasing the screw speed from 400 to 450 rpm led to a 2.8% increase in mass flow rate. Increasing the extruder water and conditioner steam resulted in a 5.3% decrease and nearly 8.6% rise in mass flow rate, respectively. On the other hand, increasing screw speed from 350 to 400 rpm had no significant effect on some of the extrudate properties such as moisture content, bulk density, water absorption index, and pellet durability. However, as screw speed increased from 350 to 400 rpm, water stability and water activity increased by 13 and 58%, respectively. Increasing screw speed from 400 to 450 rpm decreased water stability and water activity significantly. Increasing extruder water from 0.236 to 0.302 kg/min led to a significant increase in water stability, and a decrease in water absorption index, water activity and expansion ratio by 12.5, 13, 21, and 5.5%, respectively. As conditioner steam increased from 0.1 to 0.15, sinking velocity and water absorption index decreased by 25 and 15%, respectively. Increasing conditioner steam from 0.1 to 0.12 kg/min resulted in a 20%, 5.5%, 10% and 3% decrease in moisture content of the products, brightness(L*), water stability and expansion ratio, respectively. It also increased bulk density by 5.8% and unit density by 4.2%. Overall, all trials produced viable extrudates with properties appropriate for Nile tilapia production.