Application of extrusion technology in plant food processing byproducts: An overview

Buriti (Mauritia flexuosa) shell flour: Nutritional composition, chemical profile, and antioxidant potential as a strategy for valuing waste from native Brazilian fruits

The Cerrado is one of the most biodiverse biomes in the world, characterized by a wealth of native fruits with unique nutritional characteristics. In this sense, the social, economic, and environmental importance of fully utilizing food is widely recognized. Therefore, generally considered waste, fruit shells can be transformed into a coproduct with high added value. The objective of this work was to carry out a comprehensive assessment of the physicochemical properties, carbohydrate and fatty acid profile, phytochemical compounds, phenolic profile, and antioxidant potential of the recovered extracts of buriti (Mauritia flexuosa) shells in natura and dehydrated at 55 °C (flour). In addition, the functional properties were verified by thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and Fourier transform infrared spectroscopy (FTIR) from buriti shell flour. The results indicated high fiber content and energy value for the sample processed at 55 °C (58.95 g/100 g and 378.91 kcal/100 g, respectively) and low lipid and protein content (1.03 g/100 g and 1.39 g/100 g, respectively). Regardless of the sample analyzed, maltose was the majority sugar (37.33 - 281.01 g/100 g). The main fatty acids detected were oleic acid (61.33 - 62.08 %) followed by palmitic acid (33.91 - 34.40 %). The analysis of the mineral profile demonstrated that the samples did not differ significantly from each other, showing that the drying process did not interfere with the results obtained (p ≤ 0.05). The analysis of individual phenolics allowed the identification of six phenolic compounds in buriti shells. However, it is possible to observe that the drying method had a positive and significant influence on the phenolic profile (p ≤ 0.05), with chlorogenic acid (2.63 - 8.27 mg/100 g) and trigonelline (1.06 - 41.52 mg/100 g), the majority compounds. On the other hand, it is important to highlight that buriti shells have a high content of carotenoids, mainly β-carotene (27.18 - 62.94 µg/100 g) and α-carotene (18.23 - 60.28 µg/100 g), also being positively influenced by the drying process at 55 °C (p ≤ 0.05). The dried shells showed a high content of phytochemical compounds and high antioxidant activity based on the different methods tested. The results show that buriti shell flour can be fully utilized and has nutritional and chemical aspects that can be applied to develop new sustainable, nutritious, and functional food formulations.

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.

Properties of Biocomposites Made of Extruded Apple Pomace and Potato Starch: Mechanical and Physicochemical Properties

This paper presents research results on biocomposites made from a combination of extruded apple pomace (EAP) and potato starch (SP). The aim of this work was to investigate the basic properties of biocomposites obtained from extruded apple pomace reinforced with potato starch. The products were manufactured by hot pressing using a hydraulic press with a mould for producing samples. The prepared biocomposites were subjected to strength tests, surface wettability was determined, and a colour analysis was carried out. A thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), and cross-sectioning observed in a scanning electron microscope (SEM) were also performed. The obtained test results showed that the combination of apple pomace (EAP) and starch (SP) enabled the production of compact biocomposite materials. At the same time, it was found that each increase in the share of starch in the mixture for producing biocomposites increased the strength parameters of the obtained materials. With the highest share of starch in the mixture, 40%, and a raw material moisture content of 14%, the material had the best strength parameters and was even characterised by hydrophobic properties. It was also found that materials with a high content of starch are characterised by increased temperature resistance. The analysis of SEM microscopic photos showed well-glued particles of apple pomace, pectin, and gelatinised starch and a smooth external structure of the samples. Research and analyses have shown that apple pomace reinforced only with the addition of starch can be a promising raw material for the production of simple, biodegradable biocomposite materials.

Effect of Starch Types on the Textural and Rehydration Properties of Extruded Peanut Protein Pore Gel Particles

In this study, the effect of different starches from corn, potato and pea containing varying amylose/amylopectin ratios on the textural and rehydration properties of extruded peanut protein gel particles were investigated. Results showed that textural and rehydration properties of peanut protein extruded with corn starch, potato starch and amylopectin are slightly inferior to those of peanut protein with pea starch extrudates. The addition of pea starch led to an increase in the pore structure of the peanut protein extrudates and improved their water absorption index, simultaneously reducing the hardness and density. Pea starch, as a natural water-absorbing expansion material, helped peanut protein to form cross-linked gel polymers that bind more water molecules, in addition to further polymerization with peanut protein, which made the protein secondary structure became disordered. These changes directly affected the textural properties of the extrudates. In addition, the blended system of starches and peanut protein tended to form more elastic solids, which affected the expansion of the extrudates. These findings indicate that starch can effectively improve the poor expansion of proteins, making it suitable for use in the production of plant protein-based foods.

Nutritionally Valuable Components and Heat-Induced Contaminants in Extruded Snack Products Enriched with Defatted Press Cakes

This research studies the influence of the addition of defatted press cakes (from the production of hazelnut, camelina, pumpkin, and hemp seed oil) on nutritionally important components: fibre, resistant starch, polyphenols, hydroxymethylfurfural (HMF), and acrylamide in directly and indirectly expanded snacks. The amounts of press cakes added to corn grits were 3, 6, and 9%. Extrusion was carried out in a laboratory single-screw extruder. For indirectly expanded products (SCFX), supercritical CO2 was injected during extrusion, and secondary expansion was completed in the microwave oven. The type and content of press cake, as well as the type of product, significantly influenced total polyphenol content and antioxidant activity. Press cakes increased the contents of both soluble and insoluble fibre (from 1.94% d. m. and 1.28% d. m. for extrudates without press cakes up to 3.17% d. m. and 6.94% d. m. for SCFX extrudates with press cakes, respectively), and resistant starch was not markedly influenced by their addition. The influence of the content of press cake on HMF was not significant, whereas the type of cake and the type of extrusion influenced HMF significantly. In a raw mixture of corn grits with 3% of pumpkin press cake, HMF was below the limit of detection, and the highest content was found in the classically extruded sample with the addition of 9% of camelina press cake (580 ppb). In all samples, the acrylamide content was below the limit of detection, indicating that safe products were obtained. This research shows potential for the implementation of supercritical CO2 extrusion in the production of safe, nutritionally improved snack products. Future research might bring about the design of cost-effective processes applicable in the industry.

Mechanism of feed moisture levels in extrusion treatment to improve the instant properties of Chinese yam (Dioscorea opposita Thunb.) flour

Extruded yam flour was prepared at different feed moisture to improve its instant properties. The water solubility index (WSI) and water absorption index (WAI) were used to compare the instant properties of yam flour. Their chemical compositions, particle size distribution, crystalline structure, and microscopic forms were also analyzed to assess the effects of feed moisture on the instant properties of yam flour. We found that extrusion significantly improved the instant properties of yam flour, while the WSI value increased from 29.50% to 71.86% and the WAI value decreased from 387.88% to 228.06% with decreased feed moisture. Extrusion led to the degradation of total starch and amylopectin, and the contents of soluble substances increased markedly. Extrusion destroyed the granular and crystalline structures, which were reconstituted as amylose-lipid complexes with a significant decrease in relative crystallinity. Increasing the feed moisture was beneficial to the flow and color retention, while lower feed moisture was more favorable to enhance the instant properties.

Mathematical optimisation of extruded mixed plant protein-based meat analogues based on amino acid compositions

Developing meat analogues of superior amino acid (AA) profiles in the food industry is a challenge as plant proteins contain less of some essential AA than animal proteins. Mathematical optimisation models such as linear/non-linear programming models were used to overcome this challenge and create high-moisture meat analogues (HMMA) with AA profiles as close as possible to chicken breast meat. The effect on the physiochemical properties and specific mechanical energy (SME) of the HMMA was investigated. The AA content of HMMA was generally lower than chicken. Strong intermolecular bonds present in the globulin fraction could hinder protein acid hydrolysis of HMMA. Plant proteins also affect the HMMA colour as certain AA forms Maillard reaction products with higher browning intensity. Lastly, different characteristics of plant proteins resulted in different SME values under the same extrusion conditions. While mathematical programming can optimise plant protein combinations, fortification is required to match the AA profile of HMMA to an animal source.

Relationship between Physicochemical, Techno-Functional and Health-Promoting Properties of Fiber-Rich Fruit and Vegetable By-Products and Their Enhancement by Emerging Technologies

The preparation and processing of fruits and vegetables produce high amounts of underutilized fractions, such as pomace and peel, which present a risk to the environment but constitute a valuable source of dietary fiber (DF) and bioactive compounds. The utilization of these fiber-rich products as functional food ingredients demands the application of treatments to improve their techno-functional properties, such as oil and water binding, and health-related properties, such as fermentability, adsorption, and retardation capacities of glucose, cholesterol, and bile acids. The enhancement of health-promoting properties is strongly connected with certain structural and techno-functional characteristics, such as the soluble DF content, presence of hydrophobic groups, and viscosity. Novel physical, environmentally friendly technologies, such as ultrasound (US), high-pressure processing (HPP), extrusion, and microwave, have been found to have higher potential than chemical and comminution techniques in causing desirable structural alterations of the DF network that lead to the improvement of techno-functionality and health promotion. The application of enzymes was related to higher soluble DF content, which might be associated with improved DF properties. Combined physical and enzymatic treatments can aid solubilization and modifications, but their benefit needs to be evaluated for each DF source and the desired outcome.

A review of green methods used in starch-polyphenol interactions: physicochemical and digestion aspects

The interactions of starch with lipids, proteins, and other major food components during food processing are inevitable. These interactions could result in the formation of V-type or non-V-type complexes of starch. The starch-lipid complexes have been intensively studied for over five decades, however, the complexes of starch and polyphenols are relatively less studied and are the subject of recent interest. The interactions of starch with polyphenols can affect the physicochemical properties and its digestibility. The literature has highlighted several green methods such as ultrasound, microwave, high pressure, extrusion, ball-milling, cold plasma etc., to assist interactions of starch with polyphenols. However, comprehensive information on green methods to induce starch-polyphenol interactions is still scarce. Therefore, in light of the importance and potential of starch-polyphenol complexes in developing functional foods with low digestion, this review has summarized the novel green methods employed in interactions of starch with flavonoids, phenolic acids and tannins. It has been speculated that flavonoids, phenolic acids, and tannins, among other types of polyphenols, may have anti-digestive activities and are also revealed for their interaction with starch to form either an inclusion or non-inclusion complex. Further information on the effects of these interactions on physicochemical parameters to understand the chemistry and structure of the complexes is also provided.

Fresh Chokeberry (Aronia melanocarpa) Fruits as Valuable Additive in Extruded Snack Pellets: Selected Nutritional and Physiochemical Properties

In this paper, the nutritional value and (selected) physiochemical properties of extruded snack pellets enriched with fresh chokeberry (Aronia melanocarpa) fruits were analyzed from the perspective of being a new product for the functional food sector. The purpose of this study was to determine the effect of the addition of fresh chokeberry and variation in content and screw speed on extruded snack pellet basic compositions, fatty acid profiles, antioxidant activity, as well as water absorption and solubility indexes, fat absorption and color profiles. The obtained results revealed a significant increase in antioxidant activity for all samples (above 90% of free radical scavenging) in comparison to potato-based control samples (just over 20% of free radical scavenging). The total phenolic content assay revealed the most valuable results for samples enriched with 30% chokeberry, while Ultra Performance Liquid Chromatography (UPLC) analysis allowed the determination of the most important phenolic acids. Of interest, chokeberry addition decreased the fat absorption index (FAI) after expansion by frying. Moreover, the highest values of crude protein and crude ash were observed in snack pellets supplemented by the application of 30% chokeberry. In such samples, the crude protein content was at the level of 4.75-4.87 g 100 g-1 and crude ash content at 4.88-5.07 g 100 g-1. Moreover, saturated fatty acids (SFA) content was lower in snack pellets with chokeberry addition, and increasing the amount of chokeberry additive from 10% to 30% in extruded snack pellet recipes resulted in more than double an increase in polyunsaturated fatty acids (PUFA) proportion in the total fatty acids.

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.

Cereal bran proteins: recent advances in extraction, properties, and applications

The projected global population is expected to reach around 9.7 billion by 2050, indicating a greater demand for proteins in the human diet. Cereal bran proteins (CBPs) have been identified as high-quality proteins, with potential applications in both the food and pharmaceutical industries. In 2020, global cereal grain production was 2.1 billion metric tonnes, including wheat, rice, corn, millet, barley, and oats. Cereal bran, obtained through milling, made up 10-20% of total cereal grain production, varying by grain type and milling degree. In this article, the molecular composition and nutritional value of CBPs are summarized, and recent advances in their extraction and purification are discussed. The functional properties of CBPs are then reviewed, including their solubility, binding, emulsifying, foaming, gelling, and thermal properties. Finally, current challenges to the application of CBPs in foods are highlighted, such as the presence of antinutritional factors, low digestibility, and allergenicity, as well as potential strategies to improve the nutritional and functional properties by overcoming these challenges. CBPs exhibit nutritional and functional attributes that are similar to those of other widely used plant-based protein sources. Thus, CBPs have considerable potential for use as ingredients in food, pharmaceutical, and other products.

Third-Generation Snacks Manufactured from Andean Tubers and Tuberous Root Flours: Microwave Expansion Kinetics and Characterization

Andean tubers and tuberous roots have nutritional and medicinal properties transferred through ancestral generations. In this study, we aim to promote cultivation and consumption by developing a snack based on these crops. Corn grits were thoroughly mixed with sweet potato, mashua, and three varieties of oca flour (white, yellow, and red) in an 80:20 ratio, and a single-screw laboratory extruder was utilized to produce third-generation (3G) dried pellets. Microwave expansion was studied, and the dried 3G pellets and expanded snacks were characterized. The microwave expansion curves of the dried 3G pellets were adjusted to the Page, logarithmic, and Midilli-Kucuk models. During the characterization, the influence of the raw material composition was observed in sectional expansion, water content, water activity, water absorption, water solubility, swelling, optical and textural properties, and bioactive compounds. According to global color variation (mixture vs. expanded and dried vs. expanded) and bioactive compound analysis, the mashua suffered little chemical change or nutritional loss during the process. The extrusion process was shown to be an ideal method for manufacturing snacks from Andean tuber flours.

Changes in the cocoa shell dietary fiber and phenolic compounds after extrusion determine its functional and physiological properties

The influence of different extrusion conditions on the cocoa shell (CS) dietary fiber, phenolic compounds, and antioxidant and functional properties was evaluated. Extrusion produced losses in the CS dietary fiber (3-26%), especially in the insoluble fraction, being more accentuated at higher temperatures (160 °C) and lower moisture feed (15-20%). The soluble fiber fraction significantly increased at 135 °C because of the solubilization of galactose- and glucose-containing insoluble polysaccharides. The extruded CS treated at 160 °C-25% of feed moisture showed the highest increase of total (27%) and free (58%) phenolic compounds, accompanied by an increase of indirect (10%) and direct (77%) antioxidant capacity. However, more promising results relative to the phenolic compounds' bioaccessibility after in vitro simulated digestion were observed for 135°C-15% of feed moisture extrusion conditions. The CS' physicochemical and techno-functional properties were affected by extrusion, producing extrudates with higher bulk density, a diminished capacity to hold oil (22-28%) and water (18-65%), and improved swelling properties (14-35%). The extruded CS exhibited increased glucose adsorption capacity (up to 2.1-fold, at 135 °C-15% of feed moisture) and α-amylase in vitro inhibitory capacity (29-54%), accompanied by an increase in their glucose diffusion delaying ability (73-91%) and their starch digestion retardation capacity (up to 2.8-fold, at 135 °C-15% of feed moisture). Moreover, the extruded CS preserved its cholesterol and bile salts binding capacity and pancreatic lipase inhibitory properties. These findings generated knowledge of the CS valorization through extrusion to produce foods rich in dietary fiber with improved health-promoting properties due to the extrusion-triggered fiber solubilization.

Food manufacturing foreign divestment and domestic investment in developed countries

Whilst there is some literature on the effect of inward foreign direct investment on domestic investment for the whole economy and the agricultural sector, that of foreign divestment on domestic investment for food manufacturing is rare. This paper contributes to the literature by estimating the crowding effect of foreign divestment on domestic investment in the food manufacturing sector using an unbalanced panel of 29 countries from 1991 to 2019. Foreign divestment crowded out domestic investment for developed countries in the short and long runs. In terms of the absolute reduction in domestic investment, the short-run effect is higher than the long-run effect. Policies to attract inward foreign direct investment and retain it should be pursued.

Spent Grain: A Functional Ingredient for Food Applications

Spent grain is the solid fraction remaining after wort removal. It is nutritionally rich, composed of fibers—mainly hemicellulose, cellulose, and lignin—proteins, lipids, vitamins, and minerals, and must be managed properly. Spent grain is a by-product with high moisture, high protein and high fiber content and is susceptible to microbial contamination; thus, a suitable, cost-effective, and environmentally friendly valorization method of processing it is required. This by-product is used as a raw material in the production of many other food products—bakery products, pasta, cookies, muffins, wafers, snacks, yogurt or plant-based yogurt alternatives, Frankfurter sausages or fruit beverages—due to its nutritional values. The circular economy is built on waste reduction and the reuse of by-products, which find opportunities in the regeneration and recycling of waste materials and energy that become inputs in other processes and food products. Waste disposal in the food industry has become a major issue in recent years when attempting to maintain hygiene standards and avoid soil, air and water contamination. Fortifying food products with spent grain follows the precepts of the circular bio-economy and industrial symbiosis of strengthening sustainable development. The purpose of this review is to update information on the addition of spent grain to various foods and the influence of spent grain on these foods.

Enriched Pea Protein Texturing: Physicochemical Characteristics and Application as a Substitute for Meat in Hamburgers

There is currently a growing trend towards the consumption of vegetable protein, even if it shows some deficiencies in essential amino acids. It has been driven by consumer passion for health and wellness, environmental sustainability, animal welfare and the flexitarian lifestyle. However, the formulation of plant protein food analogues to meat products is complicated by the technological properties of isolated plant protein. One of the processes used to improve these properties is the texturisation of the protein by extrusion, as well as the use of other plant materials that can enrich the formulation. Therefore, the aim of this study was to evaluate the effect of pea protein (PP) enriched with lucerne (L), spinach (S) and Chlorella (C) in powdered and texturised forms on the physicochemical properties and extrusion parameters, and to evaluate its technological and sensory quality as a meat analogue in vegetal hamburgers. Texturisation reduced the number of soluble components released, thus reducing the molecular degradation in extruded material. The texturised samples were significantly (p < 0.05) less hygroscopic than the non-textured samples. Once the properties of the powder and texturised had been analysed, they were used to prepare vegetal hamburgers. The addition of vegetable-enriched texturised samples with high chlorophyll content led to more intense colour changes in the vegetal hamburgers during cooking, with PP+C providing the darkest colouring, and also resulted in a final product more similar to a traditional meat hamburger, with higher overall and meat odour/flavour intensity, hardness, juiciness and chewiness, and less legume and spice odour and flavour. Overall, texturisation improved the technological properties of the enriched protein isolate, allowing for more efficient production of vegetal hamburgers.

Understanding effects of glutelin on physicochemical and structural properties of extruded starch and the underlying mechanism

This work studied effects of different amounts of rice glutelin (RG) on physicochemical and structural properties of extruded rice starch (ERS) and explored the underlying mechanism of interaction between rice starch and RG upon extrusion processing. The results showed that the addition of RG altered the pasting properties, improved the viscoelastic, and increased the water mobility of ERS. The weight loss of ERS decreased from 71.40 % to 62.61 %, while the degradation temperature increased from 290.48 °C to 296.25 °C as the RG content increased from 0 % to 12 %. The complex index of extruded starch-glutelin complexes significantly elevated from 10.40 % to 35.81 % when RG content increased from 6 % to 12 %. Fourier-transform infrared spectra confirmed that RG interacted with starch via Maillard reactions, and the binding strength between RG and starch was enhanced at a higher RG content. Furthermore, results of rheological property and chemical interactions demonstrated that hydrogen bonding, hydrophobic, and electrostatic interaction were formed between RG and starch during extrusion. In summary, the obtained results of this study can further enrich the theory of starch-protein interactions and show the possibility of RG applied in the extruded starchy foods.

Development, Characterization and Sensory Evaluation of an Extruded Snack Using Fig Molasses By-Product and Corn Semolina

The effects of extrusion process parameters on the physicochemical, pasting and technological properties of ready-to-eat snacks were evaluated. The aim was to develop fortified extruded products with fig molasses by-product powder (FMP), which is created as a result of the production of fig molasses, is not currently used in food industry, and may cause environmental problems. The feed humidity was changed to 14-17-20%, the die temperature was 140-160-180 °C and the ratio of FMP was 0-7-14% at a fixed screw speed of 325 rpm. The study showed that adding FMP to extruded products had a significant effect on colour properties, water solubility and water absorption index properties. İncreasing the FMP ratio had a significant reducing effect on dough properties of non-extruded mixtures such as peak viscosity (PV), final viscosity (FV) and setback viscosity (SB). The optimum conditions for the production of snacks were found to be 7% FMP, 155.44 °C die temperature and 14.69% humidity. It was determined that the estimated values of water absorption index (WAI) and water solubility index (WSI) for the products manufactured under ideal extrusion conditions were close to the obtained values, and that there was no significant difference between the estimated values of the other response variables and their actual values.

Effect of enrichment of rice snacks with pulse seed coats on phenolic compound content, product features and consumer hedonic response

This study investigated the impact of seed coats from peas (PC) and chickpeas (CC) (at 15 % and 30 % levels) on rice-based co-extruded snacks. Using PC and CC reduced the content of soluble (29 %) and cell-wall bound phenolic acids (21 %), but it enhanced the amount and the profile of flavonoids of rice-based snacks (up to 16 times with PC), resulting in significantly higher antioxidant activity (134 %). Snacks with 15 % CC showed a higher section area (about 335 versus 191 mm2) and a lower average pore radius (20.1 versus 23.9 mm) than PC-snacks; however, such features did not affect either texture or porosity. At 30 % level, PC resulted in a more porous structure (porosity: 73.1 versus 66.7 %) with smaller pores (17.2 versus 27.3 mm) and high firmness (55.9 versus 40.1 N). Consumers' acceptability evaluation revealed that samples containing pulse seed coat were comparable and preferred to the control (i.e., 100 % polished rice).

Nutritional and bioactive characteristics of buckwheat, and its potential for developing gluten‐free products: An updated overview

In the present era, food scientists are concerned about exploiting functional crops with nutraceutical properties. Buckwheat is one of the functional pseudocereals with nutraceutical components used in the treatment of health-related diseases, malnutrition, and celiac diseases. As a preferred diet as a gluten-free product for celiac diseases, buckwheat is a good source of nutrients, bioactive components, phytochemicals, and antioxidants. The general characteristics and better nutritional profile of buckwheat than other cereal family crops were highlighted by previous investigations. In buckwheats, bioactive components like peptides, flavonoids, phenolic acids, d-fagomine, fagopyritols, and fagopyrins are posing significant health benefits. This study highlights the current knowledge about buckwheat and its characteristics, nutritional constituents, bioactive components, and their potential for developing gluten-free products to target celiac people (1.4% of the world population) and other health-related diseases.

Quality Characteristics of Novel Pasta Enriched with Non-Extruded and Extruded Blackcurrant Pomace

Fruit pomace is a valuable by-product in terms of its chemical composition, which potential might be used through transformation of the pomace into food ingredients. The aim of this work was to assess the effect of partial (5% and 10%) substitution of powdered non-extruded or extruded blackcurrant pomace for semolina in pasta formula on nutritional and technological properties of the final product. The pasta was assessed for chemical composition, DPPH antiradical activity, color, cooking and textural properties. Presence of the by-products in the pasta resulted in increased total dietary fiber content (from 1.89 ± 0.06 up to 10.03 ± 0.15 g/100 g, dwb), fat content (from 1.29 ± 0.01 up to 2.70 ± 0.05 g/100 g, dwb) and DPPH antiradical activity (from 253 ± 15 up to 1037 ± 7 µmol TE/g, dwb), as well as in significantly different color (p < 0.05) as compared to the semolina-only pasta. The optimal cooking time was shortened by 1.0−1.5 min and by 2.0 min in the case of the lower and higher, respectively, level of pasta supplementation. The water absorption decreased by up to 32% in the enriched pasta. In general, the cooking loss remained unchanged. The uncooked product containing the extruded fruit pomace was characterized by significantly higher breaking strength (p < 0.05) as compared to the standard pasta. Presence of the pomace also affected texture of the cooked pasta, increasing its firmness and hardness and, when using the non-extruded pomace, the tensile strength. In our research, we have shown that durum wheat pasta enriched with 5 or 10% of powdered blackcurrant pomace or their extrudates constitute a food product of improved nutritional value and of appropriate textural characteristics, while maintaining culinary properties that meet pasta industry requirements.

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.

Effect of the Addition of Soybean Residue (Okara) on the Physicochemical, Tribological, Instrumental, and Sensory Texture Properties of Extruded Snacks

An extrusion process was used to improve the physical and textural characteristics of an extruded snack supplemented with soybean residue (okara). An extreme vertices mixture design with a constraint for okara flour (0−50%), mung bean flour (20−70%), and rice flour (20−80%) resulted in the production of eleven formulations. The color, radial expansion index (REI), bulk density, tribological behavior, and instrumental and sensory texture of the extruded snacks were evaluated. Increasing the quantity of okara resulted in an extrudate with a darker, redder color, decreased REI, increased bulk density, and decreased crispness. The tribological pattern of the snack was determined by its dominant composition (protein, starch, or fiber) in the flour mixture, which contributed to the stability of the lubricating film under rotational shear. A principal component analysis of sensory data captured a total of 81.9% variations in the first two dimensions. Texture appeal was inversely related to tooth packing (r = −0.646, p < 0.05). The optimized formulation for texture preference had an okara content of 19%, which was 104% crispier and 168% tougher than an okara content of 40%. This by-product of soybean milk processing can thus be used to develop gluten-free snacks with desirable physical characteristics and texture.

Plant-Based Meat Analogues from Alternative Protein: A Systematic Literature Review

This study aimed to conduct a systematic literature review (SLR) of the research performed in the plant-based meat analogues area. Historical, current, and future tendencies are discussed. The paper offers a comprehensive SLR coupled with a bibliometric analysis of the publication from 1972 to January 2022. The articles were obtained using a research string and precise inclusion and exclusion criteria from two prominent databases, Scopus and Web of Science (WoS). The Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) flow technique was used to describe the data screening and selection. In total, 84 publications were selected for further analysis after a thorough literature assessment. From this study, six main themes were identified: (1) objectives of the study; (2) type of plant protein; (3) product type; (4) added ingredients; (5) texturization technique; and (6) quality assessment considered in the studies. Recent trends in publication imply that meat analogue technology is gaining prominence. This review revealed significant research on improving meat analogues via texturization. Even though extrusion is used industrially, the technique is still in its infancy and needs improvement. Future studies should focus more on fiber and protein-protein interactions, macromolecule conformation and mechanisms, diversifying or improving current methods, sensory attributes, and gastrointestinal absorption rate of each novel protein ingredient.

Study of the Utilization of Spent Grain from Malt Whisky on the Quality of Wafers

This study aimed at determining the quality parameters of the wafer formulated with the addition of grain spent (SG), resulting from the obtainment of whisky. In this sense, wafers were formulated from chickpea flour, spent grain, wild garlic paste, golden flaxseed, and hemp seeds. These food products were analyzed in terms of texture, density, and pH of the batter, but also of the final product for proximate analysis, baking loss, texture, water activity, color, antioxidant capacity, water holding capacity and oil holding capacity, microstructure, and sensorial analysis. The addition of spent grain in the wafer formulation led to products with a high acceptability, the texture of the batter underwent changes due to the addition of spent grain, all parameters increased, and only adhesiveness decreased. The density and pH of the samples with SG decreased. The fracturability of the products with SG decreased with the addition of SG compared to the control sample, and the color becomes darker, influenced by the specific color of the SG. With the addition of spent grain, it increases the fiber and protein content, the antioxidant capacity, but also the baking loss due to the fibers contained in it. The microstructure of samples with the addition of SG shows a heterogeneous distribution of pores on the cross section of the samples, with larger pores in the center of the wafer samples.

Surmounting the off-flavor challenge in plant-based foods

Plant-based food products have been receiving an astronomical amount of attention recently, and their demand will most likely soar in the future. However, their unpleasant, intrinsic flavor and odor are the major obstacles limiting consumer's acceptance. These off-flavors are often described as "green," "grassy," "beany," "fatty" and "bitter." This review highlights the presence and formation of common off-flavor volatiles (aldehydes, alcohols, ketones, pyrazines, furans) and nonvolatiles (phenolics, saponins, peptides, alkaloids) from a variety of plant-based foods, including legumes (e.g. lentil, soy, pea), fruits (e.g. apple, grape, watermelon) and vegetables (e.g. carrot, potato, radish). These compounds are formed through various pathways, including lipid oxidation, ethanol fermentation and Maillard reaction (and Strecker degradation). The effect of off-flavor compounds as received by the human taste receptors, along with its possible link of bioactivity (e.g. anti-inflammatory effect), are briefly discussed on a molecular level. Generation of off-flavor compounds in plants is markedly affected by the species, cultivar, geographical location, climate conditions, farming and harvest practices. The effects of genome editing (i.e. CRISPR-Cas9), various processing technologies, such as antioxidant supplementation, enzyme treatment, extrusion, fermentation, pressure application, and different storage and packaging conditions, have been increasingly studied in recent years to mitigate the formation of off-flavors in plant foods. The information presented in this review could be useful for agricultural practitioners, fruits and vegetables industry, and meat and dairy analogue manufacturers to improve the flavor properties of plant-based foods.

Flavor challenges in extruded plant-based meat alternatives: A review

Demand for plant-based meat alternatives has increased in recent years due to concerns about health, ethics, the environment, and animal welfare. Nevertheless, the market share of plant-based meat alternatives must increase significantly if they are to support sustainable food production and consumption. Flavor is an important limiting factor of the acceptability and marketability of plant-based meat alternatives. Undesirable chemosensory perceptions, such as a beany flavor, bitter taste, and astringency, are often associated with plant proteins and products that use them. This study reviewed 276 articles to answer the following five research questions: (1) What are the volatile and nonvolatile compounds responsible for off-flavors? (2) What are the mechanisms by which these flavor compounds are generated? (3) What is the influence of thermal extrusion cooking (the primary structuring technique to transform plant proteins into fibrous products that resemble meat in texture) on the flavor characteristics of plant proteins? (4) What techniques are used in measuring the flavor properties of plant-based proteins and products? (5) What strategies can be used to reduce off-flavors and improve the sensory appeal of plant-based meat alternatives? This article comprehensively discusses, for the first time, the flavor issues of plant-based meat alternatives and the technologies available to improve flavor and, ultimately, acceptability.

Superheated steam processing: An emerging technology to improve food quality and safety

Heat processing is one of the most efficient strategies used in food industry to improve quality and prolong shelf life. However, conventional processing methods such as microwave heating, burning charcoal treatment, boiling, and frying are energy-inefficient and often lead to inferior product quality. Superheated steam (SHS) is an innovative technology that offers many potential benefits to industry and is increasingly used in food industry. Compared to conventional processing methods, SHS holds higher heat transfer coefficients, which can reduce microorganisms on surface of foodstuffs efficiently. Additionally, SHS generates a low oxygen environment, which prevents lipid oxidation and harmful compounds generation. Furthermore, SHS can facilitate development of desired product quality, such as protein denaturation with functional characteristics, proper starch gelatinization, and can also reduce nutrient loss, and improve the physicochemical properties of foodstuffs. The current work provides a comprehensive review of the impact of SHS on the nutritional, physicochemical, and safety properties of various foodstuffs including meat, fruits, and vegetables, cereals, etc. Additionally, it also provides food manufacturers and researchers with basic knowledge and practical techniques for SHS processing of foodstuffs, which may improve the current scope of SHS and transfer current food systems to a healthy and sustainable one.

Production and evaluation of novel functional extruded corn snacks fortified with ginger, bay leaves and turmeric powder

Abstract

Extruded corn snacks are accepted by all human ages especially children, but they have low functional value. Therefore, corn extruded snacks contain rich nutraceuticals dried herbs including Laurus nobilis (T1), Curcuma longa (T2), Zingiber officinale Roscoe (T3), and the mixture of these herbs (T4) were manufactured and analyzed. The results declared that all the herbal extruded corn snacks had significantly higher ash, fibers, minerals, and vitamins A and B6. For minerals, the highest percent of increase compared to control was achieved by Fe, K, Ca, Zn content in order, being the highest in T4. The contents of Vitamin A and B6 were ranged from 283 to 445 IU/100 g and from 0.01 to 0.08 mg/100 g for the herbal extrudates, respectively. The increased percent in herbal corn snacks relative to control ranged from 743 to 452%, 188 to 17.6%, and from 313 to 99% for total phenolics, flavonoids, and antioxidant activity. Besides, the highest number of phenolic compounds was recorded in T4. Despite the fact that approximately all herbal extruded products had good texture and color characteristics, the best formulation was T2 and T4 corn snacks. Furthermore, the extruded products were microbiologically safe for up to 9 months. The formulation of herbal-corn snacks could fulfill consumers’ requirement for ready-to-eat-healthy foods with acceptable sensory attributes and also economically suitable for the food industry.

Graphical abstract