Properties of texturized protein and performance of different protein sources in the extrusion process: A review

The need for protein is increasing due to the rapid growth of the global population. However, conventional animal meat production has caused severe environmental, land usage, and other issues. Meat substitutes can provide consumers with a high-quality alternative to protein. Texturized protein (TP) is a critical ingredient in meat substitutes and is mainly obtained through extrusion processing. Therefore, this review first discussed the essential physical properties of TP, including appearance and structure, water-holding capacity (WHC) and oil-holding capacity (OHC), texture, and sensory properties. The performance of plant and novel source proteins in extrusion processing is also summarized. The properties of the desired TP should be considered first before extrusion processing. Under different extrusion parameters, proteins from the same source can exhibit varying properties. Although the novel source proteins can adversely affect TP quality, their high yield and environmental protection are worthy of further study. This paper aims to review the impact of proteins from different sources on the properties of TP during the extrusion process and discuss practical research methods for TP.

Influence of process parameters on physical properties and specific mechanical energy of healthy mushroom-rice snacks and optimization of extrusion process parameters using response surface methodology

Ready-to-eat healthy mushroom-rice snacks were developed and processed using twin-screw extruder. A 15% of oyster mushroom power could be added to improve the nutritional values of the rice based snack. The effects of process parameters (feed moisture, screw speed and barrel temperature) on physical properties and Specific Mechanical Energy (SME) during the production were investigated. Feed moisture was varied at 12-18% wet basis and the screw speed was studied in the range of 275-425 rpm, while the barrel temperature was operated at 130-150 °C. The result indicated that bulk density differed significantly with changes in all the process parameters. An increasing barrel temperature caused higher expansion ratio, while hardness of snacks increased due to an increase of feed moisture and a decrease of screw speed. SME was considered by measuring the electric current and voltage of the extruder. As a result, feed moisture demonstrated the most influence on the SME. Feed moisture between 12 and 15% wet basis, the SME decreased with decrease in feed moisture. On the other hand, the SME decreased when the higher feed moisture was operated in the range of 15-18% wet basis. In addition, the process condition was optimized using response surface methodology. From this study, the optimum extrusion-cooking conditions with respect to the physical qualities of snacks and SME during extrusion was 13.5% of feed moisture, screw speed of 425 rpm and maximum barrel temperature at 130 °C, since these conditions provided a good quality mushroom-rice snacks and consumed low SME.

Optimization of extrusion conditions for the production of instant grain amaranth-based porridge flour

Malnutrition is one of the foremost causes of death among children below 5 years in developing countries. Development of nutrient-dense food formulations using locally available crops has been proposed as a means to combat this menace. This study optimized the extrusion process for the production of a nutritious amaranth-based porridge flour. Least cost formulations containing grain amaranth, groundnut, iron-rich beans, pumpkin, orange-fleshed sweet potato, carrot, and maize were developed and evaluated by a sensory panel (n = 30) for acceptability using the 9-point hedonic scale. Extrusion process of the most acceptable porridge flour was optimized by response surface methodology (RSM). Barrel temperature (130-170°C) and feed moisture content (14%-20%) were the independent variables which significantly (p < .05) affected in vitro protein digestibility, vitamin A retention, total polyphenol, phytic content, and iron and zinc extractabilities. Optimization of the extrusion process improved the nutritional quality of the instant flour.

Soybean-Enriched Snacks Based on African Rice

Snacks were produced by extruding blends of partially-defatted soybean flour with flours from milled or parboiled African-grown rice. The interplay between composition and processing in producing snacks with a satisfactory sensory profile was addressed by e-sensing, and by molecular and rheological approaches. Soybean proteins play a main role in defining the properties of the protein network in the products. At the same content in soybean flour, use of parboiled rice flour increases the snack's hardness. Electronic nose and electronic tongue discriminated samples containing a higher amount of soybean flour from those with a lower soybean flour content.

Effects of amaranth addition on the pro-vitamin A content, and physical and antioxidant properties of extruded pro-vitamin A-biofortified maize snacks

BACKGROUND

Pro-vitamin A-biofortified maize snacks with added leafy vegetable may have a potential as nutritious and health-promoting products, especially in addressing vitamin A deficiency, which is prevalent in developing regions. The objective of the study was to determine the effects of adding amaranth leaf powder on the physical, antioxidant properties and pro-vitamin A content of extruded pro-vitamin A-biofortified maize snacks. Extruded snacks were processed using four pro-vitamin A-biofortified maize varieties that were composited with amaranth leaf powder at 0%, 1% and 3% (w/w) substitution levels.

RESULTS

At higher amaranth concentration, the expansion ratio of the snacks decreased, while their hardness increased by as much as 93%. The physical quality of the snacks may therefore need improvement. As amaranth was increased, the phenolic content and antioxidant activity of the snacks increased as well as the pro-vitamin A content.

CONCLUSION

Pro-vitamin A-biofortified maize with added amaranth has a potential for use in nutritious and healthy extruded snacks. There are limited studies reporting on processing pro-vitamin A maize with complementary plant foods, which is common with white maize in southern Africa; thus the current study serves as a baseline.