Extrusion processing of raw food materials and by-products: A review

From waste to value: Integrating legume byproducts into sustainable industrialization

As the global demand for sustainable food sources grows, the effective utilization of agro-industrial byproducts has become increasingly essential. Among these, legume byproducts, which are often discarded as waste, hold substantial nutritional and functional properties that can significantly contribute to advancing circular economy goals within the food industry. Current research has unveiled the potential of these byproducts to enhance both environmental sustainability and economic efficiency. Rich in proteins, dietary fibers, and bioactive compounds, legume byproducts can serve as valuable resources in developing functional food ingredients. This review explores the nutritional profiles of various legume byproducts and highlights innovative processes and technologies involved in their valorization, such as fermentation, enzymatic treatments, and novel extraction techniques. Furthermore, it explores the impact of food formulations in optimizing the functional properties of legume byproduct-based ingredients, considering their impact on texture, stability, and sensory attributes. Consumer perceptions of sustainable products derived from these ingredients are also examined, emphasizing their potential to reshape modern dietary preferences toward more sustainable choices. However, despite the promising potential of these byproducts, several challenges remain to be solved, including the antinutrients factor, market limitations, limited consumer awareness, and complexities in scaling up production. In addition, it is essential to integrate circular economy principles and conduct life-cycle assessments throughout the value chain to ensure the sustainable use of legume byproducts. Addressing these challenges is critical to enhancing the valorization of legume byproducts and promoting a more comprehensive approach to food system sustainability.

Study of the Impact of Operating Parameters and the Addition of Fat on the Physicochemical and Texture Properties of Extruded Snacks

This study investigated the effects of extrusion parameters (barrel temperature, screw speed) and oil content on the physicochemical and textural properties of corn flour-based snacks, using a Box-Behnken response surface design. Significant predictive models (adjusted R2 > 90%) were established for specific mechanical energy (SME), expansion ratio, bulk density, hardness, compression work, water activity (aw) and dry matter content. The results showed that increasing oil content dramatically reduced SME (from 229.5 Wh/kg at 5% oil and 110 °C to 68.2 Wh/kg at 10% oil and 180 °C) and expansion ratio (maximum 3.73 at 145 °C, 150 rpm, 0% oil), while increasing bulk density (up to 0.271 g/cm3 at 10% oil). High oil content also led to a sharp increase in hardness (from 67.9 N at 0% oil to 466.9 N at 10% oil). Conversely, higher barrel temperature (up to 180 °C) and screw speed (up to 250 rpm) generally improved snack texture by reducing hardness and density and increasing expansion. Water activity ranged from 0.24 to 0.50 and was positively influenced by oil content and negatively by temperature and screw speed. Overall, oil content had the strongest detrimental impact on snack properties, but optimizing temperature and screw speed allowed the production of snacks with acceptable qualities.

Modulation of snack foods: An approach to overcome hidden hunger in children

The global snack foods market had grown to 585 billion USD by 2022. Consumption of snacks has gained attention at a commercial level since they are liked by people of all ages, including millennials and elderly people. An increasing trend in snacking provides a potential opportunity for delivering micronutrients to minimize hidden hunger throughout the world. Various strategies are proposed in this review for modifying these snacks to improve snacking. The practical implications, including methodologies and approaches of such strategies, have also been summarized. The raw materials used for snack development can be biofortified for additional mineral content. By-products of fruits and vegetables can be used as ingredients and nutrient sources in the food industry. Organic salts, industrial fortificants, and nutritive substitutes can be used in extrusion processing as an enrichment method. Snacks can also be reformulated to contain more nutrients. Such strategies could greatly improve not only individual health but also the global market.

Andean Pseudocereal Flakes with Added Pea Protein Isolate and Banana Flour: Evaluation of Physical-Chemical, Microstructural, and Sensory Properties

In order to obtain a highly nutritious extrudate, a combination of pseudocereals, vegetable protein, and banana flour, a fruit with high sensory acceptability, was used. The objective of the research was to produce a multi-component extrudate (ME) based on cañihua and quinoa with the addition of pea protein isolate and banana flour. The response variables evaluated were composition, expansion, hydration, colour, and hardness properties, as well as the microscopy and sensory characteristics of the flakes produced. These flakes were compared with three commercial extrudates, commercial quinoa-based extrudate (QE), commercial corn-based extrudate (CE), and commercial wheat-based extrudate (WE), which had similar characteristics. The ME showed a higher protein content compared to commercial extrudates (13.60%), and it had significant amounts of lipids, fibre, and ash. The expansion of the ME was like commercial quinoa but significantly lower than the CE and the WE in terms of expansion (p < 0.05). Regarding the absorption and solubility indices of the ME, these indicated that it had lower starch fragmentation compared to the commercial CE and WE. In addition, the instrumental hardness of the ME was higher than the commercial ones due to the complex nature of the product. Through scanning electron microscopy (SEM), it was observed that the ME showed some remaining extrusion-resistant starch granules from quinoa and cañihua with the presence of protein bodies. Finally, the flash profile described the ME as having a pronounced flavour, higher hardness, and lower sweetness, and the free sorting task allowed it to be differentiated from commercial extrudates based on its natural appearance and chocolate flavour.

Exploring the Future of Extrusion with Andean Grains: Macromolecular Changes, Innovations, Future Trends and Food Security

This review aimed to explore the impact of extrusion on Andean grains, such as quinoa, kañiwa, and kiwicha, highlighting their macromolecular transformations, technological innovations, and contributions to food security. These grains, which are rich in starch, high-quality proteins, and antioxidant compounds, are versatile raw materials for extrusion, a continuous and efficient process that combines high temperatures and pressures to transform structural and chemical components. Extrusion improves the digestibility of proteins and starches, encourages the formation of amylose-lipid complexes, and increases the solubility of dietary fiber. However, it can degrade heat-sensitive nutrients, such as certain amino acids. The role of extrusion in food innovation is highlighted, especially in the creation of healthy and functional products such as snacks, gluten-free pastas, and meat analogs. Some innovations in the extrusion process and future trends, such as the use of artificial intelligence to optimize formulations and customize products, have been presented. The importance of Andean grains in the fight against food insecurity has been emphasized. These grains can be transformed into accessible, long-lasting, and nutritious foods, diversifying the diet and taking advantage of local resources. This review aims to serve as a valuable guide for researchers, food developers, and policymakers in their pursuit of creating more accessible, nutritious, and sustainable food options to meet escalating global demands for food security and enhanced nutrition.

Traditional weaning foods and processing methods with fortification for sustainable development of infants to combat zero hunger: a review

Weaning foods are soft digestible baby foods introduced along with breast milk for infants of 6 to 24 months. Early nutrition is a crucial one for proper growth and wellbeing. Researchers have developed weaning food from locally available ingredients with appropriate processing methods without losing actual nutrients value. Despite this, micronutrient malnutrition irrespective of the country status is a potential threat. This is overcome by fortifying micronutrients in the formulated weaning foods. Typically, formulated weaning foods are prepared from fruits and cereal grains that are abundant in micronutrients. Different processing methods are adopted to maintain the original natural characteristics of the ingredients. Traditional homemade weaning foods always have an upper hand over industrialized ones. Additionally, fortification enhances the micronutrients in weaning food and helps in uprooting the hidden hunger thereby helping in the sustainable development goals. This review focuses and delivers insights on the various processing methods and cereal-fruit weaning foods as traditional homemade ready-to-serve food supplement. It also highlights the impact of fortification of weaning foods against micronutrient malnutrition. On the whole this work emphasizes on the importance of sustainable weaning foods and how babies can be brought up into healthy grown-ups achieving zero hunger.

Effect of Pea Protein Isolate-Soybean Meal Ratio on Fiber Structure and Texture Properties of High-Moisture Meat Analogs

Inadequate fibrous attributes and prohibitive pricing are pivotal barriers to the broader market penetration of meat analogs (MAs). This research endeavors to address these impediments by formulating a blend of cost-effective soybean meal (SM) and pea protein isolate (PPI) across a spectrum of ratios (PPI:SM = 1:0, 8:2, 6:4, 4:6, 2:8, and 0:1). The analysis of textural properties elucidated that the integration of SM markedly diminished the textural rigidity and mastication resistance of MAs. Employing scanning electron microscopy (SEM) and fibrillation degree metrics, it was ascertained that the most favorable fibrous architecture of MAs was attained at a PPI to SM ratio of 6:4. Further experimental evidence underscored that the synergistic interaction between SM and PPI catalyzed the conversion of free sulfhydryl groups into disulfide linkages, a pivotal mechanism in the augmentation of MAs' fibrous matrices. The conclusions drawn from this study provide substantive contributions to the formulation of superior-quality, economically viable MAs, and could potentially accelerate their market acceptance.

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.

The art and science of porous starch: understanding the preparation method and structure-function relationship

Porous starch (PS), a modified form of starch with unique properties, is attracting substantial attention for its diverse advantages and applications. Its intricate porous structure, crystalline and amorphous characteristics, and hydrophilic-hydrophobic properties stem from pore formation via physical, chemical, enzymatic, and combined synergistic methods. Porous starch offers benefits like improved gelatinization temperature, water absorption, increased surface area, tunable crystallinity, and enhanced functional properties, making it appealing for diverse food industry applications. To optimize its properties, determining the parameters governing porous structure formation is crucial. Factors such as processing conditions, starch source, and modification methods substantially impact porosity and the overall characteristics of the material. Understanding and controlling these parameters allows customization for specific applications, from pharmaceutical drug delivery systems to enhancing texture and moisture retention in food products. To date, studies shedding light on how porosity formation can be fine-tuned for specific applications are fewer. This review critically assesses the existing reports on porous starch, focusing on how preparation methods affect porosity formation, thereby influencing the product's crystallinity/hydrophilic-hydrophobic nature and overall applicability.

Effect of extrusion on the protein structure and digestibility of extruded soybean protein

BACKGROUND

Extrusion is the main method for the preparation of plant-based meat. Current studies have focused on the effect of different extrusion parameters on the texture and quality of plant-based meat, but there has been less research on their digestibility. This study determined the textural properties of extruded soybean protein (ESPro) for different extrusion parameters and the digestibility after in vitro simulated digestion experiments. The effect of extrusion on the structure and digestibility of ESPro and the relationship between them were elucidated.

RESULTS

The results demonstrated a significant improvement in the digestibility of ESPro through extrusion, with the highest values for cohesiveness, springiness, chewiness, fibrous degree, digestibility, and proportion of digested peptides with <1 kDa molecular weight at an extrusion temperature of 160 °C and a screw speed of 30 rpm (ESPro1). In addition, β-sheet content in the secondary structure of the ESPro showed a significant negative association with ESPro digestibility.

CONCLUSION

In this study, extrusion could improve the digestibility of ESPro by altering the protein structure. This advancement holds the potential for more effective applications in plant-based meats. © 2023 Society of Chemical Industry.

Eucalypt Extracts Prepared by a No-Waste Method and Their 3D-Printed Dosage Forms Show Antimicrobial and Anti-Inflammatory Activity

The pharmaceutical industry usually utilizes either hydrophobic or hydrophilic substances extracted from raw plant materials to prepare a final product. However, the waste products from the plant material still contain biologically active components with the opposite solubility. The aim of this study was to enhance the comprehensive usability of plant materials by developing a new no-waste extraction method for eucalypt leaves and by investigating the phytochemical and pharmacological properties of eucalypt extracts and their 3D-printed dosage forms. The present extraction method enabled us to prepare both hydrophobic soft extracts and hydrophilic (aqueous) dry extracts. We identified a total of 28 terpenes in the hydrophobic soft extract. In the hydrophilic dry extract, a total of 57 substances were identified, and 26 of them were successfully isolated. The eucalypt extracts studied showed significant antimicrobial activity against Staphylococcus aureus, Pseudomonas aeruginosa, Bacillus subtilis, Candida albicans, Corynebacterium diphtheriae gravis, and Corynebacterium diphtheriae mitis. The anti-inflammatory activity of the dry extract was studied using a formalin-induced-edema model in mice. The maximum anti-exudative effect of the dry extract was 61.5% at a dose of 20 mg/kg. Composite gels of polyethylene oxide (PEO) and eucalypt extract were developed, and the key process parameters for semi-solid extrusion (SSE) 3D printing of such gels were verified. The SSE 3D-printed preparations of novel synergistically acting eucalypt extracts could have uses in antimicrobial and anti-inflammatory medicinal applications.

The Screening and Identification of a Dextranase-Secreting Marine Actinmycete Saccharomonospora sp. K1 and Study of Its Enzymatic Characteristics

In this study, an actinomycete was isolated from sea mud. The strain K1 was identified as Saccharomonospora sp. by 16S rDNA. The optimal enzyme production temperature, initial pH, time, and concentration of the inducer of this actinomycete strain K1 were 37 °C, pH 8.5, 72 h, and 2% dextran T20 of medium, respectively. Dextranase from strain K1 exhibited maximum activity at 8.5 pH and 50 °C. The molecular weight of the enzyme was <10 kDa. The metal ions Sr2+ and K+ enhanced its activity, whereas Fe3+ and Co2+ had an opposite effect. In addition, high-performance liquid chromatography showed that dextran was mainly hydrolyzed to isomaltoheptose and isomaltopentaose. Also, it could effectively remove biofilms of Streptococcus mutans. Furthermore, it could be used to prepare porous sweet potato starch. This is the first time a dextranase-producing actinomycete strain was screened from marine samples.

Trends and challenges of fruit by-products utilization: insights into safety, sensory, and benefits of the use for the development of innovative healthy food: a review

A significant portion of the human diet is comprised of fruits, which are consumed globally either raw or after being processed. A huge amount of waste and by-products such as skins, seeds, cores, rags, rinds, pomace, etc. are being generated in our homes and agro-processing industries every day. According to previous statistics, nearly half of the fruits are lost or discarded during the entire processing chain. The concern arises when those wastes and by-products damage the environment and simultaneously cause economic losses. There is a lot of potential in these by-products for reuse in a variety of applications, including the isolation of valuable bioactive ingredients and their application in developing healthy and functional foods. The development of novel techniques for the transformation of these materials into marketable commodities may offer a workable solution to this waste issue while also promoting sustainable economic growth from the bio-economic viewpoint. This approach can manage waste as well as add value to enterprises. The goal of this study is twofold based on this scenario. The first is to present a brief overview of the most significant bioactive substances found in those by-products. The second is to review the current status of their valorization including the trends and techniques, safety assessments, sensory attributes, and challenges. Moreover, specific attention is drawn to the future perspective, and some solutions are discussed in this report.

Effect of extrusion cooking on the chemical and nutritional properties of instant flours: a review

Satisfying the nutritional requirements of consumers has made food industries focus on the development of safe, innocuous, easy-to-prepare products with high nutritional quality through efficient processing technologies. Extrusion cooking has emerged as a prominent technology associated with the nutritional and functional attributes of food products. This review aims to establish a theoretical framework concerning the influence of extrusion parameters on the functional and nutritional properties of precooked or instant flours, both as end-products and ingredients. It highlights the pivotal role of process parameters within the extruder, including temperature, screw speed, and raw materials moisture content, among others, and elucidates their correlation with the modifications observed in the structural composition of these materials. Such modifications subsequently induce notable changes in the ultimate characteristics of the food product. Detailed insights into these transformations are provided within the subsequent sections, emphasizing their associations with critical phenomena such as nutrient availability, starch gelatinization, protein denaturation, enhanced in vitro digestibility, reduction in the content of antinutritional factors (ANFs), and the occurrence of Maillard reactions during specific processing stages. Drawing upon insights from available literature, it is concluded that these effects represent key attributes intertwined with the nutritional properties of the end-product during the production of instant flours.

A Review of the Changes Produced by Extrusion Cooking on the Bioactive Compounds from Vegetal Sources

The demand for healthy ready-to-eat foods like snacks is increasing. Physical modification of vegetal food matrices through extrusion generates significant changes in the chemical composition of the final product. There is a great variety of food matrices that can be used in extrusion, most of them being based on cereals, legumes, fruits, vegetables, or seeds. The aim of this review was to summarize the main effects of the extrusion process on the bioactive compounds content, namely phenolics, terpenes, vitamins, minerals, and fibers of vegetal mixes, as well as on their biological activity. The literature reported contradictory results regarding the changes in bioactive compounds after extrusion, mainly due to the differences in the processing conditions, chemical composition, physicochemical properties, and nutritional value of the extruded material and quantification methods. The thermolabile phenolics and vitamins were negatively affected by extrusion, while the fiber content was proved to be enhanced. Further research is needed regarding the interactions between bioactive components during extrusion, as well as a more detailed analysis of the impact of extrusion on the terpenes since there are few papers dealing with this aspect.

Extrusion as a tool to enhance the nutritional and bioactive potential of cereal and legume by-products

Cereal and legume by-products obtained from primary food production industries pose an environmental and economic problem. Nevertheless, these residues can potentially yield value-added products due to their elevated content of dietary fiber, phytochemicals, vitamins, minerals, and residual levels of proteins, which makes them a suitable and heightened option for reutilization in human consumption. Several studies identify extrusion as an innovative technology to modify the technofunctionality and nutritional properties of cereal and legume by-products, resulting in the production of improved ingredients. This review focuses on studies that evaluate the effect of extrusion to improve the nutritional and bioactive potential of cereal and legume by-products. A revision of the extrusion process parameters that improve the profile and bioavailability of dietary fiber, proteins, and phenolic compounds, and minimize antinutritional factors associated to cereal and legume by-products was done. The composition of by-products and process parameters such as feed moisture, barrel temperature and screw speed influence the resulting effect of extrusion. Studies suggest that extruding composite feedstock containing cereal or legume by-products may limit the molecular modifications that trigger the nutritional improvements. Therefore, extrusion applied as a pretreatment represents an interesting and economic alternative to improve the profile and bioavailability of the nutrients found in cereal and legume by-products which might lead to the development of functional ingredients useful to produce foods aimed to prevent chronic diseases.

Influence of Hulling, Cleaning and Brushing/Polishing of (Pseudo)Cereal Grains on Compositional Characteristics

(Pseudo)cereal grains have been the basis of human nutrition for thousands of years. The various types of cereals are usually harvested by grain harvesters and must be technologically processed in different ways before consumption. In addition to genotype and growing conditions, the compositional characteristics of the (pseudo)cereal grains are highly dependent on the processes used. In the present study, the effects of hulling, cleaning and brushing/polishing wheat, spelt, oat, barley, common and Tartary buckwheat grains and their fractions on physical parameters (thousand kernel weight, kernel width, fractional yield) and nutritional characteristics (protein, fat, β-glucan, macro- and microelements) were investigated. Grain samples contained 22.7-148.5 mg/g protein, 4.5-69.6 mg/g fat and 0.5-54.4 mg/g β-glucan. The content of macro- (K, Mg, P, S, Ca) and microelements (Mn, Fe, Zn, Na, Cu, Cr, Mo) varied considerably among the studied (pseudo)cereals and their grain fractions. Analysis of variance showed that species and fractions significantly influenced most of the analyzed characteristics. However, the composition of the edible fractions was not significantly dependent on the brushing/polishing process.

Preparation of Whole-Cut Plant-Based Pork Meat and Its Quality Evaluation with Animal Meat

Low-moisture (20~40%) and high-moisture (40~80%) textured vegetable proteins (TVPs) can be used as important components of plant-based lean meat, while plant-based fat can be characterized by the formation of gels from polysaccharides, proteins, etc. In this study, three kinds of whole-cut plant-based pork (PBP) were prepared based on the mixed gel system, which were from low-moisture TVP, high-moisture TVP, and their mixtures. The comparisons of these products with commercially available plant-based pork (C-PBP1 and C-PBP2) and animal pork meat (APM) were studied in terms of appearance, taste, and nutritional qualities. Results showed the color changes of PBPs after frying were similar to that of APM. The addition of high-moisture TVP would significantly improve hardness (3751.96~7297.21 g), springiness (0.84~0.89%), and chewiness (3162.44~6466.94 g) while also reducing the viscosity (3.89~10.56 g) of products. It was found that the use of high-moisture TVP led to a significant increase in water-holding capacity (WHC) from 150.25% to 161.01% compared with low-moisture TVP; however, oil-holding capacity (OHC) was reduced from 166.34% to 164.79%. Moreover, essential amino acids (EAAs), the essential amino acids index (EAAI), and biological value (BV) were significantly increased from 272.68 mg/g, 105.52, and 103.32 to 362.65 mg/g, 141.34, and 142.36, respectively, though in vitro protein digestibility (IVPD) reduced from 51.67% to 43.68% due to the high-moisture TVP. Thus, the high-moisture TVP could help to improve the appearance, textural properties, WHC, and nutritional qualities of PBPs compared to animal meat, which was also better than low-moisture TVP. These findings should be useful for the application of TVP and gels in plant-based pork products to improve the taste and nutritional qualities.

Extrusion Modification of Wheat Bran and Its Effects on Structural and Rheological Properties of Wheat Flour Dough

The study investigated the extrusion modification of wheat bran and its effects on structural and rheological properties of wheat flour dough. Extruded bran showed better solubility of dietary fiber and structural porosity, leading to higher hydration and swelling power. Addition of extruded bran to dough caused water redistribution as an intensive aggregation of bound water to gluten matrix with reduced mobility. The bran-gluten interaction influenced by water sequestering caused partial gluten dehydration and conversion of β-turn into β-sheet, which demonstrated the formation of a more polymerized and stable gluten network. Farinographic data confirmed the promotion of dough stability with extruded bran addition at lower gluten content, while viscoelastic data suggested improved dough elasticity at all gluten contents by increasing elastic moduli and decreasing loss tangent. This study would be useful for interpreting the modification effect and mechanism of extrusion on cereal brans and provide valuable guidance for applying it as an effective modification technology on the commercial production of cereal bran and its flour products.

The development process of plant-based meat alternatives: raw material formulations and processing strategies

With the rapid growth of the world's population, the demand for meat is gradually increasing. The emergence and development of plant-based meat alternatives (PBMs) offer a good alternative to solve the environmental problems and disease problems caused by the over-consumption of meat products. Soybean is now the primary material for the production of PBMs due to its excellent gelation properties, potential from fibrous structure, balanced nutritional value, and relatively low price. Extrusion is the most widely used process for producing PBMs, and it has a remarkable effect on simulating the fibrous structure of real meat products. However, interactions related to phase transitions in protein molecules or fibrous structures during extrusion remain a challenge. Currently, PBMs do not meet people's demand for realistic meat in terms of texture, taste, and flavor. Therefore, the objectives of this review are to explore how to improve fiber structure formation in terms of raw material formulation and processing technology. Factors to improve the taste and texture of PBMs are summarized in terms of optimizing process parameters, changing the composition of raw materials, and enriching taste and flavor. It will provide a theoretical basis for the future development of PBMs.

Effects of different processing techniques of broken rice on processing quality of pellet feed, nutrient digestibility, and gut microbiota of weaned piglets

The present study was conducted to assess the effect of different processing techniques of broken rice on processing quality of pellet feed, growth performance, nutrient digestibility, blood biochemical parameters, and fecal microbiota of weaned piglets. A total of 400 crossbred piglets (Duroc × Landrace × Yorkshire) with a mean initial body weight (BW) of 7.24 ± 0.52 kg were used in a 28-d experiment. Piglets were randomly distributed to one of 4 treatment and 10 replicate pens per treatment, with 10 piglets per pen. The dietary treatments were as follows: CON, corn as the main cereal type in the dietary; BR, 70% of the corn replaced by broken rice; ETBR, 70% of the corn replaced by extruded broken rice; EPBR, 70% of the corn replaced by expanded broken rice. Extruded broken rice and expanded broken rice supplementation significantly (P < 0.05) increased hardness, pellet durability index, crispness, and starch gelatinization degree. Extruded broken rice and expanded broken rice generated a higher (P < 0.05) average daily feed intake, increased (P < 0.05) average daily gain, decreased (P < 0.05) feed conversion ratio, and lowered (P < 0.05) the diarrhea rate. Piglets fed extruded broken rice displayed high apparent total tract digestibility levels of dry matter (P < 0.05), gross energy (P < 0.05), crude protein (P < 0.05), and organic matter (P < 0.05). In addition, extruded broken rice and expanded broken rice supplementation had increased Lactobacillus and Bifidobacterium levels in gut, whereas a lower abundance of the potential pathogens Clostridium_sensu_strictio_1 and Streptococcus was observed. Dietary supplementation of extruded broken rice and expanded broken rice failed to show significant effects on blood biochemical parameters. Combined, 70% corn substituted with broken rice failed to show significant effects. Collectively, extruded broken rice and expanded broken rice supplementation had positively enhanced the pellet quality, growth performance, nutrient digestibility, and gut microbiota of weaned piglets.

Inulin-type fructans and short-chain fructooligosaccharides-their role within the food industry as fat and sugar replacers and texture modifiers-what needs to be considered!

Inulin and oligofructose are classes of prebiotics belonging to a group of nondigestible carbohydrates referred to as inulin-type fructans. While short-chain fructooligosaccharides are enzymatically synthesized from the hydrolysis and transglycosylation of sucrose. Inulin-type fructans and short-chain fructooligosaccharides act as carbon sources for selective pathways supporting digestive health including altering the composition of the gut microbiota along with improving transit time. Due to their physicochemical properties, inulin-type fructans and short-chain fructooligosaccharides have been widely used in the food industry as partial replacements for both fat and sugar. Yet, levels of replacement need to be carefully considered as it may result in changes to physical and sensory properties that could be detected by consumers. Furthermore, it has been reported depending on the processing parameters used during production that inulin-type fructans and short-chain fructooligosaccharides may or may not undergo structural alterations. Therefore, this paper reviews the role of inulin-type fructans and short-chain fructooligosaccharides within the food industry as fat and sugar replacers and texture modifiers, their impact on final sensory properties, and to what degree processing parameters are likely to impact their functional properties.

From Food to Gods to Food to Waste

The present global food waste problem threatens food systems sustainability and our planet. The generation of food waste stems from the interacting factors of the need for food production, food access and availability, motivations and ignorance around food purchase and consumption, and market constraints. Food waste has increased over time. This is related to the change in how humans value food through the generations and altered human food consumption and food discard behaviors. There is also a lack of understanding of the impacts of current food production, processing and consumption patterns on food waste creation. This review examines the cultural, religious, social and economic factors influencing attitudes to food and their effects on food waste generation. The lessons from history about how humans strove toward zero waste are covered. We review the important drivers of food waste: waste for profit, food diversion to feed, waste for convenience, labeling, food service waste and household food waste. We discuss strategies for food waste reduction: recovery of food and food ingredients, waste conversion to energy and food, reducing waste from production/processing and reducing consumer food waste, and emphasize the need for all stakeholders to work together to reduce food waste.

Physicochemical Characteristics and Flavor Properties of Texturized Dual-Proteins Extrudates: Effect of Surimi to Soybean Flour Ratio

This study investigated the effects of surimi to soybean flour ratio (0:10, 1:9, 2:8, 3:7, 4:6) on the physicochemical characteristics and flavor properties of dual-proteins extrudates. The increasing ratio of surimi improved the color of extrudates and raised the apparent viscosity of the mixed raw materials, which led to the decrease of extrudates' thickness. The excess ratio of surimi and soybean flour (more than 2:8) was bad for extrudates' physicochemical characteristics with sharply decreased tensile strength, macroscopic longitudinal fracture, broken and unevenly distributed microstructure, increased water mobility and decreased free water content. However, the increasing ratio of surimi had no effect on the protein secondary structure of extrudates. Sensory evaluation, E-tongue and E-nose analysis suggested that adding surimi significantly changed the flavor properties of extrudates, with increased sweetness and umami taste, and an appropriate ratio (2:8 or 3:7) could reduce the beany flavor and without an obvious fishy off-flavor.

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.

3D-printing of oxidized starch-based hydrogels with superior hydration properties

High-hydration hydrogels based on carbohydrate polymers and green preparation methods have attracted intensive research focus recently. Driven by the attractive functions of starch, oxidized maize starch (OMS) was chosen and the related hydrogel (3D-OMS) was constructed by hot-extrusion 3D printing (HE-3DP). Meanwhile, the effect of different OMS concentrations (11 %-19 %) on its printability, structure and hydration properties were systematically investigated. The results showed that the formation of porous structure during HE-3DP environment contributed to rapid water absorption and well water holding capacity of 3D-OMS. Interestingly, as the OMS concentration increased from 11 % to 19 %, the 3D-OMS presented great hydration properties, with its maximum water absorption capacity and water holding capacity reaching 3013.43 % (11-OMS) and 93.53 % (19-OMS), respectively. Among them, 13 % was the best concentration for HE-3DP. Besides, 3D-OMS also exhibited good biodegradability and cytocompatibility. These results demonstrated potential for developing new starch-based biomedical hydrogel with great hydration properties through HE-3DP technology.

Potential interactions between starch and fruit pomace may impact the expansion ratio of direct expanded extrudates

Due to their dense characteristics, direct-expanded products fortified with insoluble fiber are generally not well accepted. Understanding the interactions between starch and fiber could help to effectively choose and modify ingredients to produce products containing high amounts of fiber. Therefore, this study aims to explain the interplay between two starches (native and waxy corn) and two pomace types (blueberry and cranberry). Blends up to 100% of pomace were extruded using a co-rotating twin-screw extruder. Raw material and milled extrudates were analyzed for their pasting and hydration properties. Fourier-transform infrared (FTIR) and solid-state nuclear magnetic resonance (NMR) spectroscopy were conducted to observe molecular changes. The expansion ratio (ER) significantly decreased as pomace was added and ranged from 3.85 for pure waxy corn starch to approximately 1 for blends that contained 80% pomace. Distinctions between the blends were observed. Particularly, at 20% of pomace inclusion, native corn starch with cranberry pomace showed a significantly higher ER. Different behaviors were also detected during the physicochemical analyses. A nonlinear trend between pomace level and water solubility as well as absorption was observed for native corn starch blends, suggesting that molecular interactions between the biopolymers occur. FTIR and NMR results give no evidence for new covalent bonds; hence, the most likely interactions occurring are hydrogen bonds. In addition to the dilution effect of pomace addition, the enhancement or weakening of such interactions between starch molecules by pomace compounds may reduce the ER.

Fortification of ready-to-eat extruded snacks with tree bean powder: nutritional, antioxidant, essential amino acids, and sensory properties

Nutrition-rich extruded snacks were developed from a mixture of cornflour, Bengal gram flour fortified by tree bean (TB) powder (0, 5, and 10%) using a twin-screw extruder. The nutritional, antioxidant, and amino acid profile and structural, functional, and sensory properties of the ready-to-eat (RTE) extruded snacks were evaluated. Ash, protein, and fiber content in TB-fortified extrudates were increased, whereas nitrogen-free extract was decreased. Total phenolics (2.34 mg g^-1 FW), ascorbate (2.23 mg g^-1 FW), total flavonoids (0.16 mg g^-1 FW), and reduced glutathione (8.53 µM g^-1 FW) were higher in the extrudates with 10% TB powder. Similarly, RTE extruded snacks fortified by 10% TB exhibited higher DPPH, FRAP, ABTS, hydroxyl radical activities, reducing power, and essential amino acids, such as lysine, leucine, isoleucine, cysteine, threonine, tyrosine, and methionine derived by HPLC. Extrudates fortified by 5% TB powder exhibited better microstructure through scanning electron microscopy. However, 10% TB powder possessed higher physicochemical properties and overall sensory attributes. This study reveals the tremendous industrial potential of nutrient-rich RTE extruded snacks fortified by underutilized TB (10%).

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Supplementary Information

The online version contains supplementary material available at 10.1007/s13197-021-05251-w.

Modifying the rheological properties, in vitro digestion, and structure of rice starch by extrusion assisted addition with bamboo shoot dietary fiber

This paper investigated the effect of extrusion treatment on the rheological properties, in vitro digestibility, and multi-structure of starch with or without bamboo shoot dietary fiber (BSDF). The viscoelasticity and thixotropy decreased after extrusion treatment, however, they increased after BSDF addition, and decreased with increasing BSDF content. The starch granules became smooth and formed big lumps after extrusion treatment. The dense lumps became loose after the addition of BSDF. Extrusion treatment changed the movement and arrangement of starch chains and thus the relative crystallinity and branching degree decreased by 92.6% and 40.9%, respectively. The disruption of starch further increased rapid digestion starch (RDS) content by 10%. The decreased disruption of starch granules and increased entanglement between BSDF and starch decreased the RDS content. The addition of BSDF is a novelty method to enhance the nutritional properties and control the physicochemical properties of extruded starchy foods.

Production and Physicochemical Characterization of Analog Rice Obtained from Sago Flour, Mung Bean Flour, and Corn Flour Using Hot Extrusion Technology

Extrusion technology allows the preparation of analog rice, an artificial product made of carbohydrate sources other than rice, with characteristics similar to natural rice. In this study, we aimed at determining the effect of composition and temperature on the nutritional content of analog rice obtained using heat extrusion technology. The physical properties and acceptability of the resulting product were also studied. Skim milk, sago, mung bean, and corn flour as well as the binder carboxymethyl cellulose (CMC) were used. The procedure was conducted in four stages: raw-material preparation, formulation, physicochemical evaluation, and sensory property evaluation. The best analog rice formula was established as 50% sago flour, 30% corn flour, 19.2% mung bean flour, 0.4% skim milk, and 0.4% CMC. The panelists’ most preferred rice analog formula was the one with the highest sago starch and skim milk content. The extrusion temperature did not significantly affect the nutrient content. However, it had a considerable impact on the thermal profile and physical properties, such as appearance and granular morphology.

Effect on Nutritional and Functional Characteristics by Encapsulating Rose canina Powder in Enriched Corn Extrudates

Wild Rose canina fruit represents a rich source of bioactive compounds such as minerals, phenolic compounds, vitamins, carotenoids, folate, and antioxidant activity that still needs to be further exploited. Thus, this study aimed to use wild Rosa canina fruit encapsulated powder with different biopolymers aiming to manufacture ready-to-eat products, such as corn extrudates. To achieve this goal, extrudate physicochemical characteristics, such as water content (x_w), water activity (a_w), water absorption index (WAI), water solubility index (WSI), swelling index (SWE), hygroscopicity (Hy), expansion index (SEI), bulk density (ρ_b), porosity (ε), textural, optical; nutritional; and functional analysis (phenolic acids, flavonoids, ascorbic and dehydroascorbic acids, vitamin C, carotenoids, folates, antioxidant activity, and minerals) were determined. Results highlighted that 4 and 8% addition of wild Rose canina fruit encapsulated powder could be successfully used in the corn extrudates, showing the positive influence on its nutritional and functional value. Strong positive Pearson correlations were identified between antioxidant capacity and total flavonoids, carotenoids, folates, and vitamin C of mixtures and extrudates Minerals increased their amount during the extrusion process, reaching the highest values at an addition of 8% rosehip encapsulated with pea protein biopolymer. Furthermore, from the biopolymers used in the present study, pea protein powder exhibited the highest protection on the analyzed bioactive compounds against the extrusion process.

Defined shear and heat treatment of apple pomace: impact on dietary fiber structures and functional properties

Food by-products can be modified by extrusion processing. However, the impact of thermal and mechanical stress, respectively, on the structure and thus functional properties of dietary fiber-rich food by-products is still unknown. In the extrusion process, thermal and mechanical stress are coupled, not constant, and difficult to measure or calculate. Thus, their influence on structural changes and functional properties cannot be evaluated separately. In this work, a specific shear cell, denoted by closed cavity rheometer, was used to treat apple pomace with defined thermal and/or mechanical stress. Dietary fiber composition and fiber polysaccharide structures appeared to be more susceptible to high temperatures than mechanical stress. With increasing temperature (and mechanical stress) soluble and low-molecular-weight soluble dietary fiber contents increased, whereas insoluble fiber contents decreased. Arabinans as rhamnogalacturonan type I polysaccharides and galacturonic acid containing pectic polysaccharides were identified as being most susceptible to degradation under these conditions. Furthermore, the defined treatment affected the functional properties. Although changes in the water solubility index (WSI) and/or the water absorption index (WAI) were not detected up to 90 °C, WSI and WAI decreased significantly at a treatment temperature of 120 °C. However, at very high temperatures (160 °C), WSI and WAI increased. The application of shear and longer treatment times resulted in higher WSI values and complex viscosities as compared to low shear stress.

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Pulse-based snacks as functional foods: Processing challenges and biological potential

Despite their high nutritional value and potential health benefits, pulse intake has not increased in the last three decades. Several strategies have been implemented to increase pulse consumption, such as their incorporation in bakery products, breakfast cereals, and snacks. The inclusion of pulses in these products could be an alternative to satisfy the consumers' demand for healthy foods. However, pulse-based snacks face important challenges, including reducing antinutritional factors, achieving consumer acceptance, and consolidating the pulse-based snacks as functional foods. This review summarizes and discusses methods for producing snacks where cereals or tubers were replaced with at least 50% pulses. Also, it briefly assesses their effect on nutritional composition, antinutritional factors, sensory acceptance, and different health benefits evaluations. Extruded snacks exhibited high protein and dietary fiber and low fat content, contrary to the high fat content of deep fat-fried snacks. Meanwhile, baked snacks presented moderate concentrations of protein, dietary fiber, and lipids. Pulses must be pretreated using process combinations such as soaking, dehulling, cooking, fermentation, germination, and extrusion to reduce the antinutritional factors. Pulse-based snacks show good sensory acceptance. However, sensory evaluation should be more rigorous using additional untrained judges. Several studies have evaluated the health benefits of pulse-based snacks. More research is needed to validate scientifically the health benefits associated with their consumption. Pulse-based snacks could be an alternative to improve the nutritional composition of commercially available snacks. The use of pulses as ingredients of healthier snacks represents an important alternative for the food industry due to their low cost, sensory characteristics, high nutritional profile, and environmental benefits.

Effects of "fresh mechanically deboned meat" inclusion on nutritional value, palatability, shelf-life microbiological risk and digestibility in dry dog food

Fresh mechanically deboned meat (MDM) is usually claimed as high-quality ingredient on dry pet food recipes and this aspect may positively influence consumer choice. It is important to determine the scientifically sustainability of this claim and to assess the microbiological safety of MDM inclusion in dry pet food. Objectives were: 1) to evaluate the effect of inclusion of MDM in dry dog food on fatty acid profile and in vivo and in vitro digestibility, proposing a new system (Daisy^II Incubator) to measure the in vitro digestibility for dogs; 2) to compare palatability of dry dog food containing MDM with dry dog food in which meat by-products (MBP) are the only animal protein sources; 3) to determine, whether or not, the inclusion of that ingredient changes the microbiology and the storage quality. Results indicated that MDM product was characterized by significant higher nutritional value in terms of fatty acids profile, in vitro digestibility (HV-IVD method) and lower palatability than the MBP product. Microbiological risk assessment showed no microbiological hazards for either product. After 6-months storage, the total mesophilic bacterial count ranged between 1.77 and 2.09 log CFU/g feed, while polyamine values were higher in the MDM (0.37 g/kg) than in the MBP (0.27 g/kg). The Daisy^II Incubator was found to be a valid instrument for studying in vitro digestibility also for dogs, providing data simply, quickly, with less variability and costs than in vivo trials. In conclusion, MDM inclusion in dry dog food is microbiologically safe and it can improve its nutritional quality, at the expense of a reduced palatability. The higher polyamine levels fount in MDM-enriched petfood after 6-months storage, however, may represent a possible hazard, and further studies are still warranted.

Insights into the Thermo-Mechanical Treatment of Brewers' Spent Grain as a Potential Filler for Polymer Composites

This paper investigated the impact of twin-screw extrusion parameters on the properties of brewers’ spent grain. The chemical structure, antioxidant activity, particle size, and color properties, as well as the emission of volatile organic compounds during extrusion, were investigated. The main compounds detected in the air during modifications were terpenes and terpenoids, such as α-pinene, camphene, 3-carene, limonene, or terpinene. They could be considered as a potential threat to human health and the environment. Changes in the chemical structure, antioxidant activity, and color of materials after modification indicated the Maillard reactions during extrusion, which resulted in the generation of melanoidins, especially at higher temperatures. This should be considered an exciting feature of this treatment method because modified brewers’ spent grain may improve the thermooxidative stability of polymer materials. Moreover, the impact of the brewers’ spent grain particle size on color and browning index used to determine the melanoidins content was investigated. The presented results show that proper adjustment of extrusion parameters enables the preparation of brewers’ spent grain with the desired appearance and chemical properties, which could maximize the efficiency of the modification process.

Utilization of Food Processing By-products in Extrusion Processing: A Review

The processing of agricultural products into value-added food products yields numerous by-products or waste streams such as pomace (fruit and vegetable processing), hull/bran (grain milling), meal/cake (oil extraction), bagasse (sugar processing), brewer's spent grain (brewing), cottonseed meal (cotton processing), among others. In the past, significant work in exploring the possibility of the utilization of these by-products has been performed. Most by-products are highly nutritious and can be excellent low-cost sources of dietary fiber, proteins, and bioactive compounds such as polyphenols, antioxidants, and vitamins. The amount of energy utilized for the disposal of these materials is far less than the energy required for the purification of these materials for valorization. Thus, in many cases, these materials go to waste or landfill. Studies have been conducted to incorporate the by-products into different foods in order to promote their utilization and tackle their environmental impacts. Extrusion processing can be an excellent avenue for the utilization of these by-products in foods. Extrusion is a widely used thermo-mechanical process due to its versatility, flexibility, high production rate, low cost, and energy efficiency. Extruded products such as direct-expanded products, breakfast cereals, and pasta have been developed by researchers using agricultural by-products. The different by-products have a wide range of characteristics in terms of chemical composition and functional properties, affecting the final products in extrusion processing. For the practical applications of these by-products in extrusion, it is crucial to understand their impacts on the qualities of raw material blends and extruded products. This review summarizes the general differences in the properties of food by-products from different sources (proximate compositions, physicochemical properties, and functional properties) and how these properties and the extrusion processing conditions influence the product characteristics. The discussion of the by-product properties and their impacts on the extrudates and their nutritional profile can be useful for food manufacturers and researchers to expand their applications. The gaps in the literature have been highlighted for further research and better utilization of by-products with extrusion processing.