Effect of screw speed and die temperature on physicochemical, textural, and morphological properties of soy protein isolate-based textured vegetable protein produced via a low-moisture extrusion

In this study, textured vegetable protein (TVP) based on soy protein isolate, wheat gluten, and corn starch was prepared at a 5:3:2 (w/w) ratio using a low-moisture extrusion process. To evaluate the effects of extrusion parameters, die temperature and screw rotation speed, on the properties of TVP, these two parameters were manipulated at a constant barrel temperature and moisture content. The results indicated that increasing the die temperature increased the expansion ratio while decreasing the density of the extrudates. Simultaneously, increasing the screw rotation speed clearly increased the specific mechanical energy of the TVP. Furthermore, mathematical modelling suggested that the expansion ratio increases exponentially to the die temperature. However, extreme process conditions bring about a decrease in water absorption capacity and expansion ratio, as well as undesirable texture and microstructure. The results suggested that the properties of SPI-based TVP are directly influenced by the extrusion process parameters, screw speed and die temperature.

Supplementary Information

The online version contains supplementary material available at 10.1007/s10068-022-01207-8.

Pearl millet based pasta: optimization of extrusion process through response surface methodology

This study investigated the influence of extrusion operating condition [barrel temperature (BT) (50-90 °C), feed moisture content (FM) (25-35%, w.b.), feeder speed (FS) (8-16 rpm) and screw speed to feeder speed ratio (SS:FS) (8-12)] on quality of pearl millet pasta [cooking time (CT), cooking loss (CL), hydration capacity (HC), swelling capacity (SC), hardness, springiness (SP), chewiness (CH) through response surface methodology (CCRD design)]. The results indicated that raising BT and FM reduced CT, CL, but increased HC, SC, hardness, SP, CH of pearl millet based pasta. HC, SC, hardness, SP and CH of pasta were increased as FS and SS:FS increased, whereas, CT and CL showed decreasing trend. The optimum operating conditions for pear millet based pasta was obtained at BT of 70 °C, FM of 30% (w.b.), FS of 12 rpm and SS:FS ratio of 10 with low CT (≤ 5.25 min), CL (≤ 7.45%) and high HC (≥ 2.30 g g^-1), SC (≥ 3.14 ml g^-1), good hardness (≥ 11.11 N), SP (≥ 1.24 N) and CH (≥ 6.09 N mm).

Effect of Moisture Content and Screw Speed on the Physical Chemical Properties of an Extruded Crab-based Snack

Crab processing generates by-products that could be used in new value-added products to decrease processing waste and increase profits. In this product development study, the effects of moisture content and screw speed on physical properties and composition of an extruded crab-based snack product were investigated. Corn meal was fortified with 10% ground crab leg and passed through a twin-screw extruder using moisture contents of 25% and 30% and screw speeds of 200, 250 and 300rpm for a total of six treatments, extruded in duplicate. Screw speed and moisture content had a significant (p 0.05) influence on moisture content, expansion ratio, crunchiness and L-value of the extrudate while protein, fat, ash and mineral were not significantly (p 0.05) affected. As screw speed increased, moisture content and bulk density of the extrudates decreased. The snack product extruded at 25% moisture content and 300rpm had significantly different (p 0.05) physical properties compared to all other treatments. Increases in torque and melting temperature were observed for higher screw speed and lower extruding moisture content.

Quality evaluation of millet-soy blended extrudates formulated through linear programming

Whole pearl millet, finger millet and decorticated soy bean blended (millet soy) extrudates formulations were designed using a linear programming (LP) model to minimize the total cost of the finished product. LP formulated composite flour was extruded through twin screw food extruder at different feed rate (6.5-13.5 kg/h), screw speed (200-350 rpm, constant feed moisture (14% wb), barrel temperature (120 °C) and cutter speed (15 rpm). The physical, functional, textural and pasting characteristics of extrudates were examined and their responses were studied. Expansion index (2.31) and sectional expansion index (5.39) was found to be was found maximum for feed rate and screw speed combination 9.5 kg/h and 250 rpm. However, density (0.25 × 10(-3) g/mm(3)) was maximum for 9.5 kg/h and 300 rpm combination. Maximum color change (10.32) was found for 9.5 kg/h feed rate and 200 rpm screw speed. The lower hardness was obtained for the samples extruded at lowest feed rate (6.5 kg/h) for all screw speed and feed rate at 9.5 kg/h for 300-350 rpm screw speed. Peak viscosity decreases with all screw speed of 9.5 kg/h feed rate.

Physical Properties and Sixth Graders' Acceptance of an Extruded Ready-to-Eat Sweetpotato Breakfast Cereal

Extruded ready-to-eat breakfast cereals (RTEBCs) were made from varying levels of sweetpotato flour (SPF), whole-wheat bran (WWB), and extrusion cooking. Moisture, protein, and ash contents were lower in the 100% SPF than the 100% WWB. Carbohydrate, beta-carotene, and ascorbic acid contents were higher in the 100% SPF. Fat, thiamin, riboflavin contents, bulk densities, and the water absorption index were similar for the cereals. However, the expansion ratio was highest in the 100% SPF cereal. The 100% WWB had the lightest color and most fibrous morphology. Extruded RTEBC containing 100% SPF and 75%/25% SPF/WWB were well-liked and acceptable to sixth graders attending an elementary school in Auburn, Alabama, but the 100% WWB was unacceptable.