Dietary fiber profile of barley flour as affected by extrusion cooking

Gluten-Free Snacks with Micronized and Freeze-Dried Red Potatoes: Nutritional and Pro-Health Values

The application of micronization to previously freeze-dried red potatoes significantly increased their polyphenol content and antioxidant potential. As a result, they became a valuable additive for enriching gluten-free snacks with bioactive compounds. The aim of this study was to assess the health-promoting potential as well as the content of polyphenols, phytosterols, and vitamin E in gluten-free extrudates, also referred to as gluten-free snacks, with the addition of 10% to 40% freeze-dried and micronized red potatoes. Additionally, the study examined color parameters and nutritional composition, including dietary fiber content. It was found that the extrudates obtained from micronized and freeze-dried red potatoes were characterized by high nutritional value but, most importantly, a strong health-promoting potential due to their exceptionally high content of phenolic acids and anthocyanins, which contributed to their remarkable antioxidant activity. Snacks enriched with freeze-dried and micronized red potatoes contain significantly higher levels of protein (3- to 14-fold increase), ash (4.5- to 22.5-fold increase), and soluble dietary fiber fraction (10- to 26-fold increase) compared to the control sample. Moreover, these snacks exhibited very high concentrations of chlorogenic, cryptochlorogenic, and neochlorogenic acids, as well as elevated levels of pelargonidin and peonidin glycosides-polyphenolic compounds that were not detected in the control sample. These snacks contained substantial amounts of tocopherols and phytosterols, such as stigmasterol and beta-sitosterol (3- to 10-fold increase compared to the control). The study conclusively demonstrated that the 40% addition of freeze-dried and micronized red potatoes to gluten-free extrudates ensures the development of an innovative product with excellent health benefits and strong antioxidant activity.

Research Progress on the Physicochemical Properties of Starch-Based Foods by Extrusion Processing

Extrusion is a crucial food processing technique that involves mixing, heating, shearing, molding, and other operations to modify the structures and properties of food components. As the primary energy source material, the extrusion process induces significant physical and chemical changes in starch that impact the quality of final products. This review paper discusses novel technologies for starch extrusion and their influence on the physical and chemical properties of starch-based foods, such as gelatinization and retrogradation properties, structural characteristics, and digestion properties. Additionally, it examines the application of extrusion in starch processing and the interactions between starch and other food components during extrusion. This information sheds light on the structural and property alterations that occur during the extrusion process to create high-quality starch-based foods.

The influence of processing technologies on the biological activity of carbohydrates in food

Food processing transforms raw materials into different food forms using physical or chemical techniques. Recently, carbohydrates have gained attention for their diverse biological activities like antioxidant, anticancer, and antimutagenic effects. Selecting suitable processing methods is crucial to preserve the beneficial properties of carbohydrates. This review discusses the impact of non-thermal and thermal processing on the physicochemical and biological traits of carbohydrates, highlighting the need for understanding the mechanisms underlying these changes. Future research will focus on enhancing and safeguarding the biological and functional aspects of carbohydrates through improved processing techniques. The goal is to optimize methods that maintain the beneficial properties of carbohydrates, maximizing their health benefits for consumers.

Safflower cake as an ingredient for a composite flour development towards a circular economy: extrusion versus conventional mixing

Food waste is responsible for the loss of 1.3 billion tons of food, some of which are related to by-products with great nutritional and energy potential that are still underexplored, such as safflower cake derived from the oil extraction industry. Therefore, the aim of this study was to evaluate the effects of incorporating safflower cake (Carthamus tinctorius) and the mixing method used to produce composite wheat-based flour in order to develop a new ingredient. The results were analyzed using ANOVA, and the Tukey test was applied at a significance level of 5 %. The composite flours obtained by the conventional mixing method showed, when compared to wheat flour, a higher concentration of proteins (+5g 100 g-1), minerals (+86 mg kg-1 of Fe, +30 mg kg-1 of Zn), phenolic compounds (15 mg GAE g-1), flavonoids (0.3 mg QE g-1), and lower oil absorption (-0.5 g oil g sample-1), making them suitable for hot flour-based sauces, salad dressings, frozen desserts, cookies and fried products. While extruded composite flours presented better homogenization, reduction of moisture (1 g 100 g-1), lipids (3 g 100 g-1), and mycotoxin concentrations, increased antioxidant activity (DPPH -0.07 IC50 mg/L and ORAC +9 µmol Trolox Eq/g), water absorption and solubility indexes, and oil absorption index, making it suitable for bakery products, meat, and dairy sausages. The developed composite flour proved to be a good nutritional ingredient; thus, its consumption can represent an important nutritional strategy with low production costs, as well as a sustainable solution, reducing food waste and, therefore, toward the concepts of the circular economy.

Effects of food processing on in vitro glucose release of high methylester pectin-enriched doughs

The incidence of type 2 diabetes is linked to consuming processed, high-glycemic foods low in dietary fiber. Soluble dietary fibers are known to improve blood glucose tolerance. This study examined the impact of processing on the in vitro glucose release of fiber-rich, high-glycemic foods. The impact of composition and microstructure on in vitro glucose release and starch digestibility was evaluated in doughs - untreated, baked at 180 °C, and extruded at 150 °C and 180 °C - with partial enrichment of high-methylester pectin. Pectin enrichment decreased starch digestibility, altered the food matrix, and doubled in vitro chyme-viscosity resulting in reduced glucose release in baked (180 °C), and extruded (150 °C) products. Baking or extrusion cooking increased starch digestibility - converting slowly into rapidly available starch and free glucose. Additionally, resistant starch levels were enhanced by up to fivefold. The variations in glucose release originated from a complex interplay between starch digestibility, viscosity, and the food matrix.

Feeding Value of Lupins, Field Peas, Faba Beans and Chickpeas for Poultry: An Overview

Grain legumes are fair sources of protein, amino acids and energy, and can be used as a replacement for soybean meal in poultry feed formulations as the soybean meal becomes short in supply and costly. However, a concern associated with the use of grain legumes in poultry feeding is the presence of antinutritional factors. The effective processing and utilisation of these grain legumes in poultry feeding are well documented. The current review focuses on four selected grain legumes (lupins [Lupinus albus and Lupinus angustifolius], field peas [Phaseolus vulgaris], faba beans [Vicia faba] and chickpeas [Cicer arietinum]) and their nutrient content, the presence of antinutritional factors, processing methods and feeding value, including updated data based on recent research findings.

Cereal β-d-Glucans in Food Processing Applications and Nanotechnology Research

Cereal (1,3)(1,4)-β-d-glucans, known as β-d-glucans, are cell wall polysaccharides observed in selected plants of grasses, and oats and barley are their good natural sources. Thanks to their physicochemical properties β-d-glucans have therapeutic and nutritional potential and a specific place for their functional characteristics in diverse food formulations. They can function as thickeners, stabilizers, emulsifiers, and textural and gelation agents in beverages, bakery, meat, and extruded products. The objective of this review is to describe the primary procedures for the production of β-d-glucans from cereal grains, to define the processing factors influencing their properties, and to summarize their current use in the production of novel cereal-based foods. Additionally, the study delves into the utilization of β-d-glucans in the rapidly evolving field of nanotechnology, exploring potential applications within this technological realm.

Effects of boiling and steaming process on dietary fiber components and in vitro fermentation characteristics of 9 kinds of whole grains

Whole grains (WGs) are considered as the representative sources of dietary fiber (DF). Thermal treatments can change the properties of DF, and potentially affecting the gut microbiota as well as human health. In this study, DF content and in vitro fermentation characteristics of 9 kinds of WGs (highland barley, barley, buckwheat, proso millet, quinoa, sorghum, coix seed, foxtail millet, and oats) after boiling and steaming treatments were compared. It was found that boiling and steaming treatments could both increase DF content in these grains, except for barley and foxtail millet. Processed WGs could regulate beneficial microbial genus, such as Bifidobacterium, Prevotella, Megamona and Megasphaera. Oats, quinoa, highland barley, and buckwheat after boiling treatment can produce more total short-chain fatty acids (SCFAs) than steaming treatment (p < 0.05), while barley, foxtail millet and coix seed showed opposite results. This study can provide data support for the design of WGs diets and the development of WGs products which are beneficial for gut health.

Arabinoxylans Release from Brewers’ Spent Grain Using Extrusion and Solid-State Fermentation with Fusarium oxysporum and the Antioxidant Capacity of the Extracts

Brewers’ spent grain (BSG) is the most abundant byproduct generated from the beer-brewing process. BSG is a material rich in hemicellulose, composed of arabinoxylans (AX). However, the high crosslinking of this material causes low availability of AX, for which it is necessary to apply different treatments. The objective of this research is to increase the release of arabinoxylans through solid-state fermentation with Fusarium oxysporum f. sp. lycopersici using extruded brewery spent grain. First, the BSG is subjected to two types of physical treatments: extrusion at 20% moisture, 200 rpm and 50 °C (BSGe), and blade milling (BSGm). The chemical composition is determined for each sample (BSG, BSGe and BSGm). Subsequently, the solid-state fermentation process (SSF) is carried out on each sample. The fermentation kinetics at 30 °C are monitored for 7 days. Once the SSF concludes, AX are extracted, and the purity of AX is determined by the phloroglucinol colorimetric assay. Finally, the total phenolic compounds, phenolic acids and antioxidant capacity by DPPH are quantified. No significant differences (p ≥ 0.05) in the protein, lipid, ash or total dietary fiber contents are found among the samples. No significant difference (p ≥ 0.05) in the content of soluble fiber is found, although BSGe and BSGm have higher values than BSG. On the other hand, the yields of soluble AX exhibit significant differences (p ≤ 0.05) among nonfermented samples (BSG, 0.03%; BSGm, 0.53%; BSGe, 0.70%) and with SSF (BSG, 2.95%; BSGm, 6.24%; and BSGe, 9.58%). In addition, the contents of free phenolic compounds and free phenolic acids and the percent inhibition of free extracts by 2,2-diphenyl-1-picrylhydrazyl (DPPH) differ significantly (p ≤ 0.05) between samples subjected to SSF and nonfermented samples. Therefore, extrusion and SSF treatment increase AX release from BSG as well as the antioxidant capacity of the extracts.

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.

Process-Induced Changes in the Quantity and Characteristics of Grain Dietary Fiber

Daily use of wholegrain foods is generally recommended due to strong epidemiological evidence of reduced risk of chronic diseases. Cereal grains, especially the bran part, have a high content of dietary fiber (DF). Cereal DF is an umbrella concept of heterogeneous polysaccharides of variable chemical composition and molecular weight, which are combined in a complex network in cereal cell walls. Cereal DF and its distinct components influence food digestion throughout the gastrointestinal tract and influence nutrient absorption and other physiological reactions. After repeated consumption of especially whole grain cereal foods, these effects manifest in well-demonstrated health benefits. As cereal DF is always consumed in the form of processed cereal food, it is important to know the effects of processing on DF to understand, safeguard and maximize these health effects. Endogenous and microbial enzymes, heat and mechanical energy during germination, fermentation, baking and extrusion destructurize the food and DF matrix and affect the quantity and properties of grain DF components: arabinoxylans (AX), beta-glucans, fructans and resistant starch (RS). Depolymerization is the most common change, leading to solubilization and loss of viscosity of DF polymers, which influences postprandial responses to food. Extensive hydrolysis may also remove oligosaccharides and change the colonic fermentability of DF. On the other hand, aggregation may also occur, leading to an increased amount of insoluble DF and the formation of RS. To understand the structure–function relationship of DF and to develop foods with targeted physiological benefits, it is important to invest in thorough characterization of DF present in processed cereal foods. Such understanding also demands collaborative work between food and nutritional sciences.

Extruded coffee parchment shows enhanced antioxidant, hypoglycaemic, and hypolipidemic properties by releasing phenolic compounds from the fibre matrix

The dietary fibre and phenolic contents and the functional properties of extruded coffee parchment flour were studied to evaluate its possible use as an ingredient rich in dietary fibre (DF) with potential antioxidant, hypoglycaemic and hypolipidemic properties in extruded products. Coffee parchment flour treated at 160-175 °C and 25% moisture feed showed higher DF (84.3%) and phenolic contents (6.5 mg GAE per g) and antioxidant capacity (32.2 mg TE per g). The extrusion process favoured the release of phenolic compounds from the fibre matrix. Phytochemicals liberated during in vitro simulated digestion exhibited enhanced antioxidant capacity and attenuated reactive oxygen species in intestinal cells (IEC-6). However, the physicochemical and techno-functional properties were just affected by extrusion at high temperature, although extruded coffee parchment flours exhibited lower bulk density and higher swelling capacity than non-extruded ones. Extruded coffee parchment preserved the glucose adsorption capacity and enhanced the α-amylase in vitro inhibitory capacity (up to 81%). Moreover, extruded coffee parchment maintained the ability to delay glucose diffusion and exhibited improved capacity to retard starch digestion in the gastrointestinal tract. The extrusion of coffee parchment flours preserved the cholesterol-binding ability and augmented the capacity of this ingredient to bind bile salts, favouring the inhibition of pancreatic lipase by coffee parchment. These discoveries generate knowledge of the valorisation of coffee parchment as a food dietary fibre ingredient with antioxidant, hypoglycaemic, and hypolipidemic properties that are enhanced by the release of phenolic compounds from the fibre matrix through the production of extruded products.

Extrusion Processing of Rapeseed Press Cake-Starch Blends: Effect of Starch Type and Treatment Temperature on Protein, Fiber and Starch Solubility

For the valorization of oilseed press cakes into food products, extrusion can be used. A common way of applying the protein- and fiber-rich press cakes in directly expanded products is the combination thereof with starch, since starch gives a favourable texture, which correlates directly to expansion. To control product properties like expansion of protein and fiber-rich extruded products, the underlying physicochemical changes of proteins, fibers and starch due to thermomechanical input need to be comprehensively described. In this study, rapeseed press cake (RPC) was extruded and treated under defined thermomechanical conditions in a closed-cavity rheometer, pure and in combination with four starches. The impact of starch type (potato PS, waxy potato WPS, maize MS, high-amylose maize HAMS) and temperature (20/25, 80, 100, 120, 140 °C) on protein solubility, starch gelatinization (D_gel), starch hydrolysis (S_H) and fiber solubility of the blends was evaluated. The extrusion process conditions were significantly affected by the starch type. In the extruded blends, the starch type had a significant impact on the protein solubility which decreased with increasing barrel temperature. Increasing barrel temperatures significantly increased the amount of soluble fiber fractions in the blends. At defined thermomechanical conditions, the starch type showed no significant impact on the protein solubility of the blends. Therefore, the observed effects of starch type on the protein solubility of extruded blends could be attributed to the indistinct process conditions due to differences in the rheological properties of the starches rather than to molecular interactions of the starches with the rapeseed proteins in the blends.

Extrusion Process as an Alternative to Improve Pulses Products Consumption. A Review

The development of new food products obtained by extrusion processing has increased in recent years. Extrusion is used by the food industry to produce a wide variety of food products, such as ready-to-eat foods (e.g., snacks), among others. Pulses have also gained popularity as novel food ingredients in the formulation of a variety of food and food products, due to their high content of macro and micronutrients, and bioactive compounds that improve the nutritional and functional properties of the final food products. In this review, the impact of extrusion variables on proteins, carbohydrates, vitamins, phenolics and antinutritional compounds in pulses and pulse-based formulations are highlighted. Particularly, the impact of the specific mechanical energy. Also, the preservation, increase and/or reduction in those functional compounds, as a consequence of different extrusion processing conditions, are discussed.

Physicochemical properties and microstructure of corn flour-cellulose fiber extrudates

In this study, corn flour with 24% w/w moisture content was extruded, and cellulose at varied weight ratios was added in order to investigate its effect on the extrudate's physicochemical properties. Twin-screw extrusion was divided into five temperature zones, and the screw temperature profile was 60℃, 120℃, 140℃, 120℃, and 110℃, respectively, and screw speed was 150 rpm. The cellulose content was 1%-15% w/w. Results showed that the addition of cellulose led to an increase in hardness, L* and b* of the extruded samples, and a decrease in degree of expansion, a*, thermal enthalpy of the sample paste. The sample paste exhibited a solid-like characteristic. Microscopic morphology analysis showed that surface wrinkles of the sample increased with the increase of cellulose addition. The addition of cellulose can effectively increase the degree of puffing of corn flour-cellulose fiber extrudates.

Food Industry By-Products as Raw Materials in the Production of Value-Added Corn Snack Products

The addition of brewer's spent grain (BSG), sugar beet pulp (SBP) and apple pomace (AP), on the nutritional properties of directly expanded snack products based on corn grits was investigated. Snack products were produced in a laboratory single screw extruder with the addition of 5, 10 and 15% d. m. of these by-products in corn grits. Chemical composition, total phenolic content, antioxidant activity, dietary fiber, resistant starch, starch damage and pasting properties of the mixtures and extruded samples were determined. Extrusion process and by-product additions had a significant effect on the proximate chemical composition. All three by-products increased contents of both soluble and insoluble dietary fiber, while the extrusion caused a reduction of insoluble fiber and increase of soluble fiber. After the extrusion process starch damage and antioxidant activity increased, while resistant starch content and total polyphenol content decreased. According to obtained results, it can be concluded that the investigated by-products can be used in the production of nutritionally more valuable corn snacks.

Antioxidant Phytochemicals in Pulses and their Relation to Human Health: A Review

Pulses are a staple food cultivated since ancient times, which play an important role in the human diet. From a nutritional point of view, pulses are very interesting foods as they are rich in proteins, carbohydrates and dietary fibre. Dietary antioxidants are a complex mixture of hydrophilic and lipophilic compounds usually present in foods of plant origin, including pulses. In the present study, the phytochemical composition of selected pulses (common beans, fava beans, lentils, chickpeas, peas and lupins) has been reviewed in terms of their content of antioxidant compounds. The content of hydrosoluble antioxidants (organic acids, phenolic compounds), liposoluble antioxidants (tocopherols, carotenoids) and other compounds which exert antioxidant properties, such as dietary fibre and minerals (zinc, selenium), has been studied, reporting that pulses are an interesting source of these compounds, which have important health benefits, including a preventing role in cardiovascular diseases, anticarcinogenic or neuroprotective properties. It is important to take into account that pulses are not usually consumed raw, but they must be processed before consumption in order to improve their nutritional quality and their palatability, therefore, the effect of different technological and heat treatments (germination, cooking, boiling, extrusion) on the antioxidant compounds present in pulses has been also reviewed. In this regard, it has been observed that as a consequence of processing, the content of phytochemicals with antioxidant properties is usually decreased, but processed pulses maintain relevant amounts of these compounds, preserving their beneficial health effect.

Effect of high-temperature, short-time cooking conditions on in vitro protein digestibility, enzyme inhibitor activity and amino acid profile of selected legume grains

African yam beans (Sphenostylis stenocarpa), Bambara groundnut (Vigna subterranean) and Pigeon pea (Cajanus cajan) flours were extruded in a single screw extruder at two extrusion temperatures; 100 °C and 140 °C, and the effect of extrusion cooking temperature on the chemical composition; crude protein, crude fibre, ether extract and nitrogen-free extracts, protein digestibility, enzyme inhibitor activity and amino acid profiles was investigated. The crude protein, amino acid profile and ether extract of the grain legumes were negatively affected (p < 0.05) by the extrusion cooking process, with a significant increase in nitrogen-free extracts for all grain legumes, and increased crude fibre of Bambara groundnut and Pigeon pea extrudates. Extrusion cooking of African yam beans and Pigeon pea produced extrudates with significantly lower trypsin, chymotrypsin and amylase inhibitor activity as well as improved protein digestibility. However, extrusion cooking did not modify the chymotrypsin and amylase inhibitor activity of Bambara groundnut extrudates. Extrusion cooking at 140 °C compared to 100 °C significantly reduced the protein quality of extrudates resulting in 22.94-51.27%, 5.11-25.18%, and 7.78-38.42% reduction in amino acid concentration of African yam beans, Bambara groundnut and Pigeon pea, respectively.

Nutritional value of barley cereal and better opportunities for its processing as a value-added food: a comprehensive review

Barley is one of the most important cereal crops and arranged globally as fourth after wheat, rice, and corn. It is known for its beneficial effects against degenerative diseases including diabetes, obesity, hypertension, and colon inflammation which are associated with eating habits and improper lifestyles. These effects are mainly attributed to its rich dietary fibers, i.e., β-glucan composition. Moreover, barley considered as a good source of starch, minerals, vitamins, and protein pose it as an ideal food supplement. Nevertheless, about 2% of the barley global production is utilized due to unacceptable organoleptic characters. Therefore, continuous modifications are ongoing either to develop new cultivars for different purposes, or novel processing methods to improve its organoleptic characters. In this review, we provide a comprehensive overview of the macroconstituents and microconstituents of barley, its nutritional value and prebiotic effects. Further, different processing procedures performed to improve its organoleptic characters or to decrease its antinutrient levels are outlined with suggestions for further needed cultivars that could preserve the different benefits of barley and maximize its value as a major cereal crop.

An Assessment of Three Carbohydrate Metrics of Nutritional Quality for Packaged Foods and Beverages in Australia and Southeast Asia

Carbohydrate quality is an aetiological factor of diet-related disease. Indices of carbohydrate quality featuring various ratios of carbohydrates-to-dietary fibre-to-sugar have been associated with improved product and/or diet quality in westernised countries. Carbohydrate intake is especially high in Asia Pacific. Thus, this study evaluated the ability of such carbohydrate metrics to discriminate the nutritional quality of carbohydrate-rich packaged foods and beverages in Australia, Malaysia, Singapore, Thailand and the Philippines, with an additional focus on beverages. This evaluation was conducted by comparing product nutritional composition and assessing products against three national nutrient profiling models. Results showed that Australia had the highest proportion of products meeting all metrics, compared to the Southeast Asian countries. Beverages had a low adherence to all metrics compared to solid foods. Across the five countries, both processed food and beverages meeting the metrics generally contained higher dietary fibre, protein, and certain vitamins and minerals whilst having lower energy, total sugars, free sugars, trans fat and cholesterol content compared to products not meeting the metrics. The metrics were also aligned with national nutrient profiling models to identify nutritious products. In conclusion, these metrics allowed us to discriminate product nutritional quality in the countries assessed and are applicable to beverages.

Extrusion cooking of immature rice grain: under-utilized by-product of rice milling process

Immature rice grain is one of the by-products of paddy milling process. Due to being "whole grain", immature rice grains comprise the fat-rich bran layer which bring along high nutritional value as well as susceptibility to rancidity. Therefore, they are generally used as "feed" rather than "food". In this study, the potential of utilizing immature rice grain as a food ingredient was investigated. For this purpose, raw (unprocessed) and infrared (IR) stabilized immature rice grain flours (IRGF) were extruded at different exit-die temperatures (130 °C and 150 °C) and feed moisture contents (16%, 18%, 20%) and the effects of these parameters on chemical composition (moisture, crude fat, protein, ash, soluble and insoluble dietary fiber and phytic acid contents), physicochemical properties (solubility, water binding capacity, expansion index and bulk density), thiamine, riboflavin and tocopherol contents, textural and sensorial properties of the extrudates were investigated. Either thiamine or tocopherol contents of the extrudates made of unprocessed IRGF were higher than that of the extrudates made of IR stabilized IRGF (p < 0.05). Additionally, higher extrusion temperature and lower feed moisture content resulted in further loss in both vitamins. On the other side, riboflavins showed a relatively heat-stable behavior. Rancid flavor and bitter taste scores of the extrudates which were made of unprocessed IRGF were significantly higher than their counterparts made of IR stabilized IRGF (p < 0.05). Toothpack was the most dominant sensory attribute in all extrudates.

Effects of superfine grinding on asparagus pomace. Part I: Changes on physicochemical and functional properties

The effects of superfine grinding on the physicochemical and functional properties of asparagus pomace were investigated. The results showed that in terms of the specific surface area, water solubility, soluble dietary fiber content, and ratio of insoluble dietary fiber to soluble dietary fiber, finer samples usually possessed better physicochemical properties compared with coarse samples. However, grinding samples excessively to produce small particle sizes could reduce the water-holding capacity, oil-binding capacity, and swelling capacity. In addition, the extraction of both free and bound phenolics in asparagus pomace powder samples and the samples' absorption of both nitrite ion and glucose showed typical bell-shaped curves, demonstrating that superfine grinding could significantly impact the various properties of asparagus pomace. This study should provide insights into the effect of micronization on the functionalities of fiber-rich food materials. PRACTICAL APPLICATION: This article deals with the effects of superfine grinding on the physicochemical and functional properties of asparagus pomace. The results showed that the properties of asparagus pomace did not always improve gradually with decreasing particle size. With a decrease in granularity, some parameters showed a bell-shaped curve whereas others initially increased and then stabilized, indicating that in actual production, the crushing particle size should be determined according to actual needs or target parameters.

Extrusion and nixtamalization conditions influence the magnitude of change in the nutrients and bioactive components of cereals and legumes

Cereal and legume diets make up the bulk of caloric sources for a majority of households in the developing world. They contain macro- and micronutrients as well as phytochemicals embedded as one matrix. Some phytochemicals are antinutritional factors which can bind nutrients thereby hindering their bioavailability. While there are other methods that can be used to enhance nutrient utilization from such foods, we summarize how food processing methods such as extrusion and nixtamalization are employed to break the food matrix and release these nutrients. Both extrusion and nixtamalization can break down complex carbohydrates into simpler, more soluble forms while at the same time inactivating or denaturing protein inhibitors and other antinutritional factors. Such disruptions of complexes within the food matrix are essential for harnessing optimum nutritional and health benefit from these foods. We present mechanistic approaches explaining how these processes enhance nutrient and mineral bioavailability and phytochemical bioactivity while minimizing the undesirable effects of antinutritional factors that coexist in the complex food matrix.

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

The food processing industry generates an immense amount of waste, which leads to major concerns for its environmental impact. However, most of these wastes, such as plant-derived byproducts, are still nutritionally adequate for use in food manufacturing. Extrusion is one of the most versatile and commercially successful processing technologies, with its widespread applications in the production of pasta, snacks, crackers, and meat analogues. It allows a high degree of user control over the processing parameters that significantly alters the quality of final products. This review features the past research on manufacture of extruded foods with integration of various plant food processing byproducts. The impact of extrusion parameters and adding various byproducts on the nutritional, physicochemical, sensory, and microbiological properties of food products are comprehensively discussed. This paper also provides fundamental knowledge and practical techniques for food manufacturers and researchers on the extrusion processing of plant food byproducts, which may increase economical return to the industry and reduce the environmental impact.

Chemical composition and selected quality characteristics of new types of precooked wheat and spelt pasta products

New types of precooked pasta products have been developed based on refined and wholegrain wheat and spelt flours. The resulting dry pasta was then assessed for chemical composition, including amino acids composition, phenolics content, as well as antioxidant activity. The precooked pasta quality was also evaluated for starch gelatinization degree, physical properties, hardness, color profile of dry and hydrated pasta, and sensory characteristics. We found that the application of the extrusion-cooking technique for wheat and spelt pasta processing allows to achieve instant products with good nutritional characteristics and high degree of gelatinization, as well as attractive quality and sensory profiles. Microstructure showed compact and dense internal structure with visible bran particles if wholegrain flours were used. Wholegrain wheat and wholegrain spelt precooked pasta were characterized by better nutritional composition and greater antioxidant potential, but lower firmness and increased adhesiveness when compared with refined flours.

Characterization of a Mixture of Oca (Oxalis tuberosa) and Oat Extrudate Flours: Antioxidant and Physicochemical Attributes

The oca (Oxalis tuberosa) is a tuber with high starch content and excellent antioxidant properties, which can be used in the production of extruded products; however, starch-rich products can be improved nutritionally through the incorporation of fibers that can result in extrudates with beneficial health properties. The aim of this work was to develop a mixture of oca (Oxalis tuberosa) and oat extrudate flours and evaluate the antioxidant and physicochemical attributes. The results showed that a higher moisture content increased the hardness, water absorption index, and density of the extrudates; however, the solubility and expansion indexes showed an inverse pattern. The addition of oat fiber had the opposite effect from moisture content on the physicochemical properties mentioned above. The cellular antioxidant activity (CAA) of the extrudates decreased when the oat fiber increased. An inverse pattern was observed when the moisture concentration was increased. The starch hydrolysis percentage and glycemic index decreased significantly when the fiber content increased. Oat fiber contributed 67.29% and 65.04% to these parameters, respectively. Oat fiber exerted a greater effect than moisture on the collets extruded in this study according to factor contributions.

Effect of extrusion conditions on the physical properties of desi chickpea-barley extrudates and quality attributes of their resulting flours

In this study, response surface methodology (RSM) was used to evaluate the effect of extrusion conditions on physical properties of chickpea:barley extrudates (60:40), and the resulting protein quality of their flours. Barrel temperature (150-170°C) and moisture content (16-20%) were chosen as independent variables to generate a central composite design. Hardness, expansion index, bulk density, and protein quality were analyzed as responses parameters. Expansion was found to be higher at lower temperatures and higher moisture for the 60:40 chickpea:barley blend; bulk density became reduced with increased moisture; and hardness was found to increase at higher temperatures and lower moistures. The protein quality of their resulting flours was found to be greater at moisture contents higher than 16%. The composition, protein quality, and functional attributes were also examined for raw and precooked flours of chickpea, barley, and their blend at the center point of the RSM design (18% moisture, 160°C). Extrusion also leads to improved water hydration capacities and reduced viscosities for precooked individual and blended flours relative to the raw. Moreover, extrusion also led to improved protein quality in the chickpea and chickpea-barley blend, but not the individual barley flour.

Use of blackcurrant and chokeberry press residue in snack products

Fruit and vegetable processing by-products, undervalued until recently, are rich sources of nutrients. This study investigated properties of extruded corn puffs with addition (5–20%) of blackcurrant or chokeberry pressings. We assessed expansion rate, water absorption index (WAI) and water solubility index (WSI) of the produced extru-dates, the concentration of polyphenols, and antioxidant activity measured by FRAP method and ABTS method. The puffs with addition of chokeberry pressings had higher WSI values, higher phenolic acids, flavonols, and anthocyanins content, and higher antioxidant activity than puffcorn with addition of blackcurrant pressings. The corn puffs with addition of fruit pressings contained much higher concentrations of phenolic compounds and were characterized by much higher antioxidant activity than pure puffcorn. This confirms the usefulness of addition of such fruit processing by-products in order to manufacture functional food.