Effects of extrusion temperature on structure and physicochemical properties of proso millet starch

Due to its thermal stability, and high viscosity, proso millet starch has limited practical applications. Extrusion can alter the functional properties of starch by pre-gelatinization, but the specific effects of extrusion temperature on starch behavior are not clear. In this study, proso millet starch was modified using extrusion at varying temperatures (70 °C, 90 °C, 110 °C), and its structure as well as physicochemical properties were evaluated. As the extrusion temperature increased, the starch granules were gelatinized, and the particle size increased significantly. The relative crystallinity of extruded starch decreased and the short-range order was enhanced notably, but the starch still exhibited an A-type structure. Starch chains degraded, migrated, and aggregated, showing an increase in the double helix content, but there was no difference in the single helix structure with temperature. With the increase of extrusion temperature, the amorphous layer of extruded starch thickened. Moreover, the peak viscosity, breakdown viscosity and setback viscosity initially increased and then decreased, the peak temperature and enthalpy change increased. The water absorption index, water solubility and swelling power significantly decreased with increasing temperatures. The freeze-thaw stability and transparency of extruded starch decreased, and showed a downward trend with prolonged time. The above results indicate that extrusion treatment effectively modifies the thermal stability and viscosity of proso millet starch, laying a foundation for applying it different industrial applications.

Peach Peel Extrusion for the Development of Sustainable Gluten-Free Plant-Based Flours

The food industry generates substantial waste, contributing to environmental challenges, such as pollution and greenhouse gas emissions. Utilizing by-products, particularly fruit peels that are rich in fiber, antioxidants, and vitamins, presents a sustainable approach to reducing waste, while enhancing the nutritional value of food products. Specifically, peach peel can be used to produce gluten-free flours, with increased fiber content and antioxidant properties. Extrusion technology is a highly effective method for developing these functional flours, as it improves digestibility, reduces anti-nutrients, and enhances nutrient bioavailability. This study investigates the potential of combining corn flour with peach peel flour, derived from Royal Summer peachs (RSF), at different concentrations (0%, 5%, and 15%). A factorial experimental design was utilized to evaluate the impact of RSF incorporation on the proximate composition, antioxidant capacity, and functional properties of the flour. The results indicate that flours containing 15% RSF demonstrated significant improvements in terms of the dietary fiber content (5.90 g per 100 g-1) and antioxidant capacity (ABTS•+ 745.33 µmol TE per 100 g-1), meeting the "source of fiber" labelling requirements. The glycemic index of the 15% RSF flour was reduced to 78.09 compared to non-enriched flours. The functional properties of the flour, such as swelling and gelation capacities, were also enhanced with RSF incorporation. These findings highlight the potential of RSF-enriched flours in regard to the development of sustainable, health-promoting, plant-based, and gluten-free flours.

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.

Designing Nutrition for Health-Incorporating Dietary By-Products into Poultry Feeds to Create Functional Foods with Insights into Health Benefits, Risks, Bioactive Compounds, Food Component Functionality and Safety Regulations

This review delves into the concept of nutrition by design, exploring the relationship between poultry production, the utilization of dietary by-products to create functional foods, and their impact on human health. Functional foods are defined as products that extend beyond their basic nutritional value, offering potential benefits in disease prevention and management. Various methods, including extraction, fermentation, enrichment, biotechnology, and nanotechnology, are employed to obtain bioactive compounds for these functional foods. This review also examines the innovative approach of enhancing livestock diets to create functional foods through animal-based methods. Bioactive compounds found in these functional foods, such as essential fatty acids, antioxidants, carotenoids, minerals, vitamins, and bioactive peptides, are highlighted for their potential in promoting well-being and mitigating chronic diseases. Additionally, the review explores the functionality of food components within these products, emphasizing the critical roles of bioaccessibility, bioactivity, and bioavailability in promoting health. The importance of considering key aspects in the design of enhanced poultry diets for functional food production is thoroughly reviewed. The safety of these foods through the establishment of regulations and guidelines was reviewed. It is concluded that the integration of nutrition by design principles empowers individuals to make informed choices that can prioritize their health and well-being. By incorporating functional foods rich in bioactive compounds, consumers can proactively take steps to prevent and manage health issues, ultimately contributing to a healthier society and lifestyle.

Starch-guar gum-ferulic acid molecular interactions alter the ordered structure and ultimate retrogradation properties and in vitro digestibility of chestnut starch under extrusion treatment

Molecular interactions among starch and multiple-components during food processing determine the retrogradation properties and digestibility of starch. Here, the effects of starch-guar gum (GG)-ferulic acid (FA) molecular interactions on retrogradation properties, digestibility and ordered structural changes of chestnut starch (CS) under extrusion treatment (ET) were investigated by structural analysis and quantum chemistry. Due to the entanglement behaviors and hydrogen bond interactions, GG could inhibit the formation of helical and crystalline structures of CS. When FA was introduced simultaneously, FA could weaken the interactions between GG and CS as well as enter the spiral cavity of starch to increase the single/double helix and V-type crystalline structures while reducing A-type crystalline. Based on the above structural changes, ET with starch-GG-FA molecular interactions resulted in resistant starch content of 20.31% and anti-retrogradation rate of 42.98% for 21-day storage. Overall, the results could provide basic data for creation of chestnut-based food with higher value.

Kidney Bean Substitution Ameliorates the Nutritional Quality of Extruded Purple Sweet Potatoes: Evaluation of Chemical Composition, Glycemic Index, and Antioxidant Capacity

The extrusion process may influence the nutritional profiles of carbohydrate-rich food ingredients, including the glycemic index (GI) and antioxidant capacity. This study aimed to evaluate the nutritional profile of extruded purple sweet potato (EPSP) substituted with kidney bean flour (KBF) (0, 30, and 40%). These foods were further characterized by their proximate composition, resistant starch, polyphenols, GI, and antioxidant capacities. The 40% KBF substitution enhanced the protein and fiber contents of the EPSP by up to 8% and 6%, respectively. Moreover, it also revealed that EPSP with 40% KBF substitution had a low-GI category (53.1), while the 0 and 30% substitution levels had a high-GI category, i.e., 77.4 and 74.7, respectively. However, the extrusion processing reduced the anthocyanin content and antioxidant capacity of purple sweet potato flour containing 40% KBF by 48% and 19%, respectively. There was a significant relationship between the GI values of proteins, fats, and fibers (p < 0.05). The insignificant effect of resistant starch and phenol contents on GI value was recorded due to the low concentrations of those components. KBF substitution could ameliorate the profile of protein, fiber, and GI, but not for antioxidant capacity. The other innovative processes for preserving antioxidant capacity might improve the product quality.

Bioactive, Mineral and Antioxidative Properties of Gluten-Free Chicory Supplemented Snack: Impact of Processing Conditions

This study aimed to investigate the impact of chicory root addition (20-40%) and extrusion conditions (moisture content from 16.3 to 22.5%, and screw speed from 500 to 900 rpm) on bioactive compounds content (inulin, sesquiterpene lactones, and polyphenols) of gluten-free rice snacks. Chicory root is considered a potential carrier of food bioactives, while extrusion may produce a wide range of functional snack products. The mineral profiles were determined in all of the obtained extrudates in terms of Na, K, Ca, Mg, Fe, Mn, Zn, and Cu contents, while antioxidative activity was established through reducing capacity, DPPH (2,2-diphenyl-1-picrylhydrazyl) and ABTS (2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) tests. Chicory root addition contributed to the improvement of bioactive compounds and mineral contents, as well as antioxidative activities in all of the investigated extrudates in comparison to the pure-rice control sample. An increase in moisture content raised sesquiterpene lactones and minerals, while high screw speeds positively affected polyphenols content. The achieved results showed the important impact of the extrusion conditions on the investigated parameters and promoted chicory root as an attractive food ingredient in gluten-free snack products with high bioactive value.

Food extrusion: An advanced process for innovation and novel product development

Extrusion is a versatile process capable of producing a variety of new and novel foods and ingredients, thus increasing manufacturing opportunities. Further, it could provide nutritious, safe, sustainable, and affordable foods, especially directed at individualized consumer needs. In addition to past research efforts, more investigations should be conducted in order to refine, redesign, or develop new extrusion processing technologies. The present review highlights the current advances made in new and novel food product development by considering the extrusion process, the influencing parameters, and product characteristics and properties; the most promising extrusion processes that can be used in novel food product and ingredient development, such as extrusion cooking, hot-melt extrusion, reactive extrusion, and extrusion-based 3D printing; the possibilities of using various raw materials in relation to process and product development; and the needs for product development modeling along with extrusion process design and modeling. In correlation with extruded product development, topics that merit further investigation may include structure formation, plant and animal biopolymers functionalization, biopolymer reactions, process simulation, modeling and control, engineering and mechanical aspects of extruders, analysis of pre-processing treatments, as well as prototyping, risk analysis, safety, sensory and consumer acceptance.

Effects of Extrusion on Starch Molecular Degradation, Order-Disorder Structural Transition and Digestibility-A Review

Extrusion is a thermomechanical technology that has been widely used in the production of various starch-based foods and can transform raw materials into edible products with unique nutritional characteristics. Starch digestibility is a crucial nutritional factor that can largely determine the human postprandial glycemic response, and frequent consumption of foods with rapid starch digestibility is related to the occurrence of type 2 diabetes. The extrusion process involves starch degradation and order-disorder structural transition, which could result in large variance in starch digestibility in these foods depending on the raw material properties and processing conditions. It provides opportunities to modify starch digestibility by selecting a desirable combination of raw food materials and extrusion settings. This review firstly introduces the application of extrusion techniques in starch-based food production, while, more importantly, it discusses the effects of extrusion on the alteration of starch structures and consequentially starch digestibility in various foods. This review contains important information to generate a new generation of foods with slow starch digestibility by the extrusion technique.

How to synchronously slow down starch digestion and retrogradation: A structural analysis study

Digestibility and retrogradation properties of starch are important for the nutrition and quality of starch-based foods. In this study, a new idea on the synchronous delay the starch digestion and retrogradation was proposed, and the regulation mechanism was explored from perspectives of structural evolution using ¹³C NMR, XRD and SAXS techniques as well as the molecular dynamics simulations. Results showed that the chestnut starch treated with hot extrusion and 8% catechins (HE-8% CA)## could reach highest anti-retrogradation rate (AR 76.63%) and lowest rapidly digestible starch content (RDS 64.55%) at day 24. The starch digestion was slowed down by increasing single/double helix, V-type crystallinity and compactness of aggregates, while retrogradation process was suppressed by inhibiting the packing of short-range ordered structure into long-range ordered structure. The hydrogen bonding and van der Waals forces were the main driving force for the interactions between flavonoid polyphenols and starch molecules. Overall, this study is instructive for further investigations on the synchronous modulation of functional properties of starch.

Extrusion cooking of protein-based products: potentials and challenges

Extrusion cooking is receiving increasing attention as technology applied for the production of protein-based products. Researchers in this field showed that proteins from several sources are barely consumed because of their poor functionality and lack of acceptability related to the presence of some antinutritional factors. In this regard, extrusion is becoming of key importance thanks to its ability to improve protein functional properties. Based on this remarkable advantage, several studies have been published so far providing evidence of the enhanced functional, physicochemical and sensory properties of protein-based extruded products. The objective of the present review is to give a detailed overview of the potential of extrusion for the production of protein-based products. More specifically, the work describes all the studies published so far on vegetable and animal proteins including those recently released applying the technology on insect proteins. The aspects related to the functional properties of the extrudates together with the quality changes occurring during the process are also described to highlight the potential of the technology for future applications.