Development of healthy extruded maize snacks; Effects of soybean flour and feed moisture content

Proximate, structural, textural, sensory and microbiological properties of non-gluten extrudate using Sorghum (Sorghum bicolor L. Moench) and a sprouted legume (Phaseolus lunatus L.)

The inclusion of legumes as functional ingredients in a gluten-free extrusion process has been gaining attention in recent times. In this study, sorghum and germinated lima bean flour (100, 90:10, 80:20, 70:30, 60:40 and 50:50) was extruded (feed moisture - 18%, screw speed - 250 rpm, barrel temperatures 50 °C-120 °C-120 °C, die hole diameter - 3 mm) and analysed for functional, proximate, textural, structural, pasting, microbiological and sensory properties. With 100% sorghum used as control, lima beans addition significantly (p < 0.05) improved the loose (0.37-0.44 g/ml) and packed (0.63-0.72 g/ml) bulk density, while water (5.00-3.15 g/g) and oil (2.45-1.60 g/g) absorption capacity and expansion ratio (3.11-2.30) decreased, respectively. An increase in protein (12.77-18.00%), crude fibre (2.58-5.17%) and ash content (2.11-3.12%) were observed in the extrudate, while the (L*) colour parameter (54.49-43.62), hardness (180.04-78.36 N) and pasting viscosities reduced with addition of lima beans. The structural micrograph depicted air-trapped bubbles with thick walls after adding lima beans, while a notable decline in microbial count below approved limits was observed after 8 weeks of storage. Sensory scores showed that values obtained were above average with the 90:10 sorghum-lima bean ratio having the highest score. The economic and industrial value of underutilised legumes such as lima bean can be promoted as functional ingredients via extrusion in addressing coeliac disease and alternative sources of protein, especially in developing countries.

A Comprehensive Review on Harnessing Soy Proteins in the Manufacture of Healthy Foods through Extrusion

The global development of livestock production systems, accelerated by the growing demand for animal products, has greatly contributed to land-use change, greenhouse gas emissions, and pollution of the local environment. Further, excessive consumption of animal products has been linked with cardiovascular diseases, digestive system diseases, diabetes, and cancer. On the other hand, snacks, pasta, and bread available on the market are made from wheat, fat, salt, and sugar, which contribute to the risk of cardiovascular diseases. To counter these issues, a range of plant protein-based food products have been developed using different processing techniques, such as extrusion. Given the easy scalability, low cost of extrusion technology, and health benefits of soy proteins, this review focuses on the extrusion of soy protein and the potential application of soy protein-based extrudates in the manufacture of healthy, nutritious, and sustainable meat analogs, snacks, pasta products, and breakfast cereals. This review discusses the addition of soy protein to reformulate hypercaloric foods through extrusion technology. It also explores physical and chemical changes of soy proteins/soy protein blends during low and high moisture extrusion. Hydrogen bonds, disulfide bonds, and hydrophobic interactions influence the properties of the extrudates. Adding soy protein to snacks, pasta, breakfast cereals, and meat analogs affects their nutritional value, physicochemical properties, and sensory characteristics. The use of soy proteins in the production of low-calorie food could be an excellent opportunity for the future development of the soybean processing industry.

Novel Gluten-Free Breakfast Cereals Produced by Extrusion Cooking from Rice and Teff: Effects on Microstructural, Physical and Nutritional Properties

Current gluten-free products often have nutritional inadequacies. Teff is generating a growing interest for its excellent nutritional value. In this study, the effects of teff enrichment of extruded gluten-free breakfast cereals based on rice flour and two process parameters-feed moisture and temperature-were investigated based on their physical, microstructural and nutritional properties. The independent variables were modulated and examined by a Box-Behnken design. The incorporation of teff flour affected the sensory properties of extruded cereals, particularly lightness and crispness, with estimated linear effects of -6.91 and -8.49, respectively. The enrichment of breakfast cereals with teff flour also increased the total phenolic content and antioxidant capacity in both free and bound fractions, as well as the amount of insoluble dietary fibre. By varying all independent variables, the microstructural and physical properties of samples changed considerably. At the lowest feed moisture, wall thickness was small while showing the highest expansion. Samples with the highest teff flour addition exhibited an increased number of small pores which decreased crispness. These findings suggest that, by optimized extrusion cooking, the use of teff flour seems to be promising for the preparation of gluten-free breakfast cereals with superior nutritional properties and good structural characteristics.