Optimization of extrusion process for production of nutritious pellets

Abstract

A blend of 50% Potato Starch (PS), 35% Quality Protein Maize (QPM), and 15% Soybean Meal (SM) were used in the preparation of expanded pellets utilizing a laboratory extruder with a 1.5 × 20.0 × 100.0 mm die-nozzle. The independent variables analyzed were Barrel Temperature (BT) (75-140 °C) and Feed Moisture (FM) (16-30%). The effect of extrusion variables was investigated in terms of Expansion Index (EI), apparent density (ApD), Penetration Force (PF) and Specific Mechanical Energy (SME), viscosity profiles, DSC, crystallinity by X-ray diffraction, and Scanning Electronic Microscopy (SEM). The PF decreased from 30 to 4 kgf with the increase of both independent variables (BT and FM). SME was affected only by FM, and decreased with the increase in this variable. The optimal region showed that the maximum EI was found for BT in the range of 123-140 °C and 27-31% for FM, respectively. The extruded pellets obtained from the optimal processing region were probably not completely degraded, as shown in the structural characterization. Acceptable expanded pellets could be produced using a blend of PS, QPM, and SM by extrusion cooking.

Extruded snacks from whole wheat supplemented with textured soy flour: Effect on instrumental and sensory textural characteristics

“…The snacks prepared with 32% replacement levels of TSF + WWF, had the lowest value 1.49, probably due to higher addition of protein and fiber provided by TSF and WWF in the snack. In general, protein and fiber act as diluents and reduce expansion due to their ability to affect water distribution in the matrix, and to the fact that their macromolecular structure and conformation affect the extensional properties of extruded meal (Aguilar‐Palazuelos, Zazueta‐Morales, Harumi, & Martínez‐Bustos, ; Martinez‐Flores et al ., ). In general, the values obtained in our study were within the range previously reported by Korkerd, Wanlpa, Puttanlek, Uttapap, and Rungsardthong () in extruded snacks enriched with 20% of a deffated soybean meal.…”

Effect of Composition and Processing Conditions on Selected Properties of Potato-Based Pellets and Microwave-Expanded Snacks Supplemented with Fresh Beetroot Pulp

“…In starch-rich extrudates in general, proteins act as diluents and reduce expansion due to their ability to affect water distribution in the matrix, and also because their macromolecular structure and conformation affect the rheological properties of extruded blends. Proteins also contribute to the formation of extensive networking through covalent links and electrostatic interactions that take place during the extrusion-cooking [Aguilar-Palazuelos et al, 2012]. This explains the negative correlation demonstrated between VEI and protein content in our study.…”

Development of an Expanded Snack of Rice Starch Enriched with Amaranth by Extrusion Process

“…The expansion was also limited by the percentage of proteins in the formulations. Proteins exert diluting effects caused by their ability to affect the distribution of water molecules in the matrix, in addition to creating through covalent bonds and electrostatic interactions originated during extrusion [56]. Chávez-Jáuregui et al [57] reported values of expansion index of 2.32 and 2.84 in extruded amaranth; these values turn out to be greater than those obtained in the present investigation; the differences could be given by the temperatures used that were higher and lower moisture content.…”