Texturized Dairy Proteins

Biodegradation of Expanded and Extruded Polystyrene with Different Diets by Using Zophobas atratus Larvae (Coleoptera: Tenebrionidae)

Polystyrene waste pollutes the environment and poses a significant health risk to humans, animals, and marine ecology. This study aims to evaluate the effectiveness of degradation on expanded (EPS) and extruded (XPS) polystyrene with different diets using superworms (Zophobas atratus larvae) obtained in Malaysia. The growth and development of the larvae after consumption of EPS and XPS and the gut microbial community changes in response to high polystyrene consumption diets were also identified. The oatmeal, wheat bran, and cornmeal were used as supplement diets and showed significantly enhanced EPS and XPS consumption and degradation compared to sole diet treatment. Gel permeation chromatography was carried out using egested frass of Z. atratus larvae to characterize depolymerization of EPS and XPS, indicating a significant reduction in the average molecular weight and average molecular weight. The highest reduction occurred in the presence of oatmeal. Proton nuclear magnetic resonance and Fourier transform infrared spectroscopy analyses indicated functional group changes and chemical modification occurred with depolymerization and partial oxidation of EPS and XPS. The larvae length increased, while the number of instars and duration of larvae became shorter with the addition of supplement diets. Oatmeal is predominantly effective among other supplements in assisting Z. atratus larvae with EPS and XPS degradation. The results of this study support the ubiquity of polystyrene biodegradation in Z. atratus and the next-generation sequencing studies. Kluyvera sp., Klebsiella sp., and Enterobacter sp. were found to be strongly associated with degrading EPS and XPS polystyrene with oatmeal as a supplemental diet.

Extrusion-Cooking Modifies Physicochemical and Nutrition-Related Properties of Wheat Bran

The potential of extrusion-cooking to change the physicochemical characteristics of wheat bran, increase its nutritional value and decrease its recalcitrance towards fermentation was investigated in this study. The conditions in a twin-screw extruder were varied by changing screw configuration, moisture content and barrel temperature. The former was not previously investigated in studies on bran extrusion. Extrusion-cooking resulted in an increased water-holding capacity and extract viscosity of bran, suggesting shear-induced structure degradation and structure loosening due to steam explosion at the extruder outlet. Modelling showed that the extent of these modifications mainly correlates with the amount of specific mechanical energy (SME) input, which increases with an increasing number of work sections in the screw configuration and a decreasing moisture content and barrel temperature. Extrusion led to solubilisation of arabinoxylan and ferulic acid. Moreover, it led to starch melting and phytate degradation. Upon fermentation of the most modified sample using a human faecal inoculum, small numeric pH decreases and short-chain fatty acid production increases were observed compared to the control bran, while protein fermentation was decreased. Overall, extrusion-cooking can improve the nutrition-related properties of wheat bran, making it an interesting technique for the modification of bran before further use or consumption as an extruded end product.

Effects of extrusion types, screw speed and addition of wheat gluten on physicochemical characteristics and cooking stability of meat analogues

BACKGROUND

Plant protein-based products such as meat analogues have been receiving attention over the years. However, comparisons of product properties and mechanisms applied in the production of low- and high-moisture meat analogues have not been reported. In this study, the effects of extrusion types (low- and high-moisture extrusion cooking), absence or presence of added wheat gluten, as well as screw speed (150 and 200 rpm) on the physicochemical properties of meat analogues were evaluated. The mechanism of protein texturization of low- and high-moisture meat analogues was studied.

RESULTS

Extrusion types and addition of wheat gluten had a major influence on physicochemical characteristics which were critical in controlling the fibrous texture of the final product, while screw speed had a minor impact on springiness only (P < 0.001). All high-moisture meat analogues (HMMAs) were associated with a higher integrity index and greater stability of springiness and cutting strength than low-moisture meat analogues (LMMAs) using the same formula and screw speed, while the nitrogen solubility index of HMMAs was lower. Based on the physicochemical properties determined, the higher cross-link formation in HMMAs is proposed to occur in the cooling die section.

CONCLUSION

Our findings show that the utilization of high-moisture extrusion cooking and the incorporation of wheat gluten into the formula at 400 g kg^-1 could impart a fibrous and compact structure to extrudates similar to that of actual muscle meat, with a greater integrity index and texture stability. © 2019 Society of Chemical Industry.

Extrusion and Extruded Products: Changes in Quality Attributes as Affected by Extrusion Process Parameters: A Review

Extrusion of foods is an emerging technology for the food industries to process and market a large number of products of varying size, shape, texture, and taste. Extrusion cooking technology has led to production of wide variety of products like pasta, breakfast cereals, bread crumbs, biscuits, crackers, croutons, baby foods, snack foods, confectionery items, chewing gum, texturized vegetable protein (TVP), modified starch, pet foods, dried soups, dry beverage mixes etc. The functional properties of extruded foods plays an important role for their acceptability which include water absorption, water solubility, oil absorption indexes, expansion index, bulk density and viscosity of the dough. The aim of this review is to give the detailed outlines about the potential of extrusion technology in development of different types of products and the role of extrusion-operating conditions and their effect on product development resulting in quality changes i.e physical, chemical, and nutritional, experienced during the extrusion process.

Extrusion texturized dairy proteins: processing and application

The primary proteins in milk, casein and the whey proteins α-lactalbumin and β-lactoglobulin, have a number of health benefits and desirable functional properties. In a twin-screw extruder, mechanical shear forces, heat, and pressure cause considerable changes in the molecular structures of the dairy proteins, a process known as texturization. These changes further impart unique functional properties to dairy proteins, resulting in new protein-based food ingredients. The new functional behavior depends on the extent of texturization and the degree of structural change imparted and is controlled by adjusting parameters such as extrusion temperature and moisture level. Such texturized proteins can be used to produce puffed high-protein snacks. Softer gels and expanded structures can be made using supercritical fluid extrusion and cold extrusion, techniques that avoid elevated temperatures, minimizing possible damage to the nutritive components and functionality of the texturized dairy proteins. The uses of the texturized dairy ingredient in food products with improved functionality and enhanced nutritive profiles are presented.