The advantage of using extrusion processing for increasing dietary fibre level in gluten-free products

Effects of apples (Malus domestica) and their derivatives on metabolic conditions related to inflammation and oxidative stress and an overview of by-products use in food processing

Apple (Malus domestica) is the third most produced fruit worldwide. It is a well-known source of bioactive compounds mainly represented by hydroxycinnamic acids, flavan-3-ols, dihydrochalcones, dehydroascorbic acid, carotenoids, chlorogenic acid, epicatechin, and phloridzin. Due to the lack of a recent evaluation of the clinical trials associated with apple consumption, this review investigated the effects of this fruit on metabolic conditions related to inflammation and oxidative stress and reviewed the applications of apple waste on food products. Thirty-three studies showed that apples or its derivatives exhibit anti-inflammatory and antioxidant actions, improve blood pressure, body fat, insulin resistance, dyslipidemia, and reduce cardiovascular risks. Apples have a great economic impact due to its several applications in the food industry and as a food supplement since it has impressive nutritional value. Dietary fiber from the fruit pomace can be used as a substitute for fat in food products or as an improver of fiber content in meat products. It can also be used in bakery and confectionary products or be fermented to produce alcohol. Pomace phytocompounds can also be isolated and applied as antioxidants in food products. The potential for the use of apples and by-products in the food industry can reduce environmental damage.

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.

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.

Novel Gluten-Free Breakfast Cereals Produced by Extrusion Cooking from Rice and Teff: Effects on Microstructural, Physical and Nutritional Properties

Current gluten-free products often have nutritional inadequacies. Teff is generating a growing interest for its excellent nutritional value. In this study, the effects of teff enrichment of extruded gluten-free breakfast cereals based on rice flour and two process parameters-feed moisture and temperature-were investigated based on their physical, microstructural and nutritional properties. The independent variables were modulated and examined by a Box-Behnken design. The incorporation of teff flour affected the sensory properties of extruded cereals, particularly lightness and crispness, with estimated linear effects of -6.91 and -8.49, respectively. The enrichment of breakfast cereals with teff flour also increased the total phenolic content and antioxidant capacity in both free and bound fractions, as well as the amount of insoluble dietary fibre. By varying all independent variables, the microstructural and physical properties of samples changed considerably. At the lowest feed moisture, wall thickness was small while showing the highest expansion. Samples with the highest teff flour addition exhibited an increased number of small pores which decreased crispness. These findings suggest that, by optimized extrusion cooking, the use of teff flour seems to be promising for the preparation of gluten-free breakfast cereals with superior nutritional properties and good structural characteristics.

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 characterization of the extrusion-processed micronutrient-fortified corn snacks enriched with protein and dietary fiber

The current study focused on developing protein- and dietary fiber-enriched, micronutrient-fortified corn snacks using extrusion technology. Corn, soybean, and chickpea flour were used to develop micronutrient-fortified (Fe, Zn, I, and vitamin A, and C) extruded snacks, followed by an exploration of their nutritional traits. Soybean and chickpea were supplemented discretely (20-40/100 g) or in a combination of both (10:10, 15:15, and 20:20/100 g). According to the results, the relative proportion of the raw material composition was reflected in corn snacks' proximate composition and mineral and vitamin levels. Corn snacks with 40/100 g soy flour showed the best nutrient profile, with a maximum percent increase in protein (171.9%) and fiber (106%), as compared to the snacks developed using chickpea and/or mixed supplementation with soy and chickpea. Total dietary fiber (18.44 ± 0.34%), soluble dietary fiber (10.65 ± 0.13%), and insoluble dietary fiber (7.76 ± 0.38%) were also found to be highest in the soy-supplemented snacks (40/100 g). It was discovered that 100 g of corn snacks could provide 115-127% of the RDA for iron, 77-82% of the RDA for zinc, 90-100% of the RDA for vitamin A, and 45-50% of the RDA for vitamin C. The results for the effect of extrusion processing on amino acids showed a 2.55-45.1% reduction in essential amino acids, with cysteine and valine showing the greatest decrease and leucine and tryptophan remaining relatively stable during extrusion.

Reintegration of Food Industry By-Products: Potential Applications

Numerous studies have indicated that fruits and vegetables are considered as significant sources of bioactive compounds. The generated by-products, which are derived from the food industry, reveal similar or higher antioxidant activity. On the other hand, intense industrialization results in the production of large volumes of by-products, raising serious environmental issues. Therefore, this situation creates the necessity to develop new strategies in order to exploit the generated wastes, securing the ability to develop new high-added-value products. This review aims to summarize the exploitation of fruit wastes, namely, apple and citrus, as well as vegetable by-products which are derived from tomato, potato and carrot cultivation. All the aforementioned by-products have found wide applications in the development of new high-added-value products in the food and feed industry owing to their improved nutritional profiles. Furthermore, these wastes are characterized by a strong antioxidant activity, justifying their valorization in other fields such as cosmetics and pharmaceutical industries.

Twin-Screw Extrusion as Hydrothermal Technology for the Development of Gluten-Free Teff Flours: Effect on Antioxidant, Glycaemic Index and Techno-Functional Properties

Gluten-free products (GFP) currently are the fastest-growing category of baked goods probably due to the high worldwide incidence of celiac disease (CD). Refined rice is one of the most used cereal flour for GFP development, due to its high content in starch and good technological aptitude. However, its low content in fibre, protein and minerals has awakened a recent interest as alternative to balance the GF flour formulas. Teff is a cereal with high levels in fibre and antioxidants compounds but the lack of gluten results in very limited techno-functional properties. Extrusion is a thermal technology that allows to combine flours, overcoming negative impacts on quality characteristics. This study evaluated the effect of twin-screw extruder on rice-teff (white and brown) mixtures with different teff concentrations (25, 50 and 75%) on their antioxidant, glycaemic index and techno-functional properties. The results showed than the high shear−temperature process produced important modifications on the flour, which were confirmed using scanning electron microscopy (SEM). Significant increases in total dietary fibre (16 to 100% increase) were observed in teff containing flours, due to carbohydrate−lipid−protein complexes, which lead to resistant starch, with no significant increase in rice flour. Hydration and pasting properties were significantly (p > 0.05) affected by extrusion, and the effect was related to the concentration of teff used. The thermal process showed a decrease in total phenol (TP) content for rice; however, extrusion enhanced the release of total phenol in rice-teff blends, which was reflected on the antioxidant activities of blend flours, especially those prepared with brown teff.

Gluten-free grains: Importance, processing and its effect on quality of gluten-free products

Gluten-enteropathy affects a significant number of people, making gluten a major concern in the food industry. With medical advancements, the diagnosis of allergies is becoming easier, and people who are allergic to gluten are recommended a complete gluten-free diet. Since wheat provides a major part of the energy and nutrition in the diet, its elimination affects nutrition intake of allergic population. Food scientists are working to formulate products using protein-rich gluten-free grains with quality attributes at par with gluten-containing products. Focused research has been done to provide nutrition and a variety of food to people suffering from gluten-related disorders. Efforts are being made to remove the gluten from the wheat and other gluten-containing grains, while applying different processing/treatments to enhance the properties of gluten-free grains. Hence, the present review summarizes the importance, processing, and products of different gluten-free grains. It also highlights the digestibility of gluten-free grains with clinical trials and gluten elimination strategies for gluten-containing grains.

Lupin Kernel Fibre: Nutritional Composition, Processing Methods, Physicochemical Properties, Consumer Acceptability and Health Effects of Its Enriched Products

The kernels (dehulled seeds) of lupins (Lupinus spp.) contain far higher dietary fibre levels than other legumes. This fibre is a complex mixture of non-starch polysaccharides making up the thickened cell walls of the kernel. The fibre has properties of both insoluble and soluble fibres. It is a major by-product of the manufacture of lupin protein isolates, which can be dried to produce a purified fibre food ingredient. Such an ingredient possesses a neutral odour and flavour, a smooth texture, and high water-binding and oil-binding properties. These properties allow its incorporation into foods with minimum reduction in their acceptability. The lupin kernel fibre (LKF) has demonstrated beneficial effects in clinical studies on biomarkers for metabolic diseases such as obesity, type 2 diabetes, and cardiovascular disease. It can be described as a “prebiotic fibre” since it improves gut micro-floral balance and the chemical environment within the colon. Thus, LKF is a health-functional ingredient with great opportunity for more widespread use in foods; however, it is evident that more non-thermal methods for the manufacture of lupin kernel fibre should be explored, including their effects on the physicochemical properties of the fibre and the effect on health outcomes in long term clinical trials.

Evaluating the Effects of Wheat Cultivar and Extrusion Processing on Nutritional, Health-Promoting, and Antioxidant Properties of Flour

Wheat has been considered one of the most important staple foods for thousands of years. It is one of the largest suppliers of calories in the daily diet, which is added to many different products. Wheat is also a good source of health-benefiting antioxidants. This study aims toinvestigate the changes in the antioxidant properties, such as total phenol content, 2,2-diphenyl-1-picrylhydrazyl (DPPH), metal chelating activity, 2,2′-azino-bis (3-ethylbenz-thiazoline-6-sulfonic acid) diammonium salt (ABTS⁺) scavenging activity, and color intensity, during the extrusion processing of six different wheat cultivars. The extrusion factors evaluated were 15% feed moisture and two extrusion temperatures (150 and 180°C). Extrusion processing increased antioxidant activity (DPPH, metal chelating activity, and ABTS⁺ scavenging activity), whereas total flavonoids content and total phenolic content were decreased. The L^* values of wheat flours increased significantly (p < 0.05) after extrusion at 150 and 180°C, 15% mc. Furthermore, redness was decreased from control wheat cultivars (range: 0.17–0.21) to extrusion at 150°C (range: 0.14–0.17) and 180°C (range: 0.1–0.14). The study suggests that extruded wheat could improve the antioxidant potential in food products.

Beetroot as a novel ingredient for its versatile food applications

Beta vulgaris, also known as Beetroot, is a member of a family of Chenopodiaceae and is widely used as a natural food colorant. It gets its distinctive color due to nitrogen-containing water-soluble pigments betalains. Beetroot is an exquisite cradle of nutrients, including proteins, sucrose, carbohydrates, vitamins (B complex and vitamin C), minerals, fiber. They also contain an appreciable amount of phenolic compounds and antioxidants such as coumarins, carotenoids, sesquiterpenoids, triterpenes, flavonoids (astragalin, tiliroside, rhamnocitrin, kaempferol, rhamnetin). Recent studies evidenced that beetroot consumption had favorable physiological benefits, leading to improved cardiovascular diseases, hypertension, diabetes, cancer, hepatic steatosis, liver damage, etc. This review gives insights into developing beetroot as a potential and novel ingredient for versatile food applications and the latest research conducted worldwide. The phytochemical diversity of beetroot makes them potential sources of nutraceutical compounds from which functional foods can be obtained. The article aimed to comprehensively collate some of the vital information published on beetroot incurred in the agri-food sector and a comprehensive review detailing the potentiality of tapping bioactive compounds in the entire agriculture-based food sector.

Effect of Hempseed Cake (Cannabis sativa L.) Incorporation on the Physicochemical and Antioxidant Properties of Reconstructed Potato Chips

Hempseed (Cannabis sativa L.) cake is a by-product after cold-pressing of oil from the hempseed, which is rich in protein and fiber. This study investigated the effect of hempseed cake incorporation on the physicochemical and antioxidant properties of reconstructed potato chips. Varying levels of hempseed cake (0, 5%, 10%, 15%, and 20%) were added, and the results showed that the addition of hempseed cake at 20% level significantly increased the protein and total dietary fiber content from 2.74 ± 0.62 g/100 g to 9.66 ± 0.28 g/100 g and from 2.76 ± 0.31 g/100 g to 13.57 ± 0.42 g/100 g, respectively. In addition, a 20% reduction in lipid content was observed in the 20% hempseed cake addition group. Furthermore, lightness value (L*) was significantly reduced from 72.23 ± 1.22 to 46.40 ± 1.76, while the hardness was enhanced with a higher level of hempseed cake supplementation in the potato chips sample. Compared with the control (no hempseed cake), the supplement of 20% cake increased the total phenolic content from 0.19 ± 0.01 to 0.26 ± 0.01 mg GAE/g. The ABTS radical scavenging rate was also significantly enhanced with the increased levels of hemp cake. However, the peroxide value and TBARS results showed that the addition of hempseed cake accelerated the lipid oxidation in the sample, possibly due to the highly unsaturated fatty acid residues in the hempseed cake. The results suggested that more research is needed for the incorporation of hempseed cake in potato chips.

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 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.

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.

Substantiation of foamy structure formation in a gluten-free biscuit

A promising way to create gluten-free foods based on purposeful use of ingredients with a wide range of technological properties is analyzed. Steps to regulate the structural and mechanical properties of gluten-free dough have been determined. These steps allow to improve the structural-mechanical and organoleptic characteristics of the biscuit semi-finished product, to adjust the nutritional value. To determine the technological effect, we considered the connection between the recipe components and the properties of the dough when forming a foamy structure of gluten-free cupcake products. The influence of the design parameters of the mixer (independent factors xi) on the foaming process (Q) has been determined, that is, determining the productivity magnitude from the changes of three main factors: from the attack angle of the frontal surface of the plate working body α, the distance between the plates (step) t and the rotation frequency of working body n. The stability of the foam formed and the rate of its settling and the role of the liquid phase of the dough during short storage before baking were investigated. The comparative characteristics of the microstructure of wheat flour (WF) and extruded corn flour (ECF) in the ratios are presented: a) WF – 100 wt.%; b) WF: ECF – 80:20 wt.%; c) ECF – 100 wt.%. In the tested mixtures, the moisture-holding capacity increases for the sample containing 20% by weight of extruded corn flour two and a half times, and three times for the sample with extruded flour to 100% by weight. With an increasing proportion of extruded corn flour in the flour mixture, the dough density increases and the optimum value is in the range of 0.444 – 0.446 kg.m-3. The comparative characteristic of the microstructure of the samples is given, which has the appearance of foam with the existing and even distribution of air bubbles which later form the porous structure of the biscuit of the semi-finished product. Thus, the size of the formed bubbles of air with the content of wheat flour and starch have a large difference in diameters, in the sample of biscuit dough using ECF 100 wt.% – almost the same size, and between the channels are formed that promote the equalization of air pressure in the middle of the foam system of biscuit dough. It was found that the use of 20 wt.% and 100 wt.% of corn extruded flour contributes to the formation of a fine porous structure of biscuit dough.

Production of high fiber ready-to-eat expanded snack from barley flour and carrot pomace using extrusion cooking technology

The effects of feed moisture content (14, 17 and 20% db), die temperature (120, 145 and 170 °C) and carrot pomace content (10, 17.5 and 25%) on the sectional expansion index, hardness, porosity, micro and macro structure and sensory properties of high fiber expanded barley-carrot pomace snack were investigated using a central composite design. Results showed that with increasing the moisture content the hardness of the extruded snacks increased while their expansion ratio decreased. The hardness decreased with increasing the die temperature, but the expansion ratio increased with increasing the die temperatures to up to 145 °C and decreased afterwards. An increase in carrot pomace content decreased the expansion ratio and cell average size while the hardness and cell wall thickness increased. The optimum condition for production of expanded barley-carrot pomace snack was 10% carrot pomace content, 142.7 °C die temperature and 14.02% moisture content. During extrusion cooking, the soluble dietary fiber of barley-carrot pomace snack increased, but no change on the total dietary fiber content was observed. Therefore, the extruded snacks prepared from barley flour and carrot pomace had high nutritional value.

Potato Starch Utilization in Ecological Loose-Fill Packaging Materials-Sustainability and Characterization

Biodegradable materials are used in the manufacture of packaging and compostable films and various types of medical products. These have demonstrated high potential in medical applications: cardiac, vascular and orthopaedic conditions in adults as well in children. In our research, the extrusion-cooking technique was used to obtain environmentally friendly loose-fill foams as packaging. Potato starch was the basic raw material. Polyvinyl alcohol was used as an additive in the amount of 1%, 2% and 3% to replace starch. The components were mixed and moistened with water to various initial moisture contents of the blend (17%, 18% and 19%). The processing of starch foams employed the TS-45 single screw extruder-cooker (Gliwice, Poland) with the L/D ratio of 12. The foams were processed with various screw speeds (100 and 130 rpm) and with two types of forming dies (circular and ring die). The extrusion-cooking process efficiency (kg h⁻¹) and the energy consumption (kWh kg⁻¹) during the processing were also measured. The results showed that the processing efficiency of potato starch foams varied depending on the level of polyvinyl alcohol, the shape of the forming die and the screw speed applied. The analysis of energy consumption, mechanical properties and FTIR analyses demonstrated that the type of the forming die and the initial moisture level had the most significant impact on specific energy demands during the processing of potato starch-based foams.

Apple Pomace as a Functional and Healthy Ingredient in Food Products: A Review

Apple pomace is a major by-product obtained during apple juice processing. Several million metric tons of apple pomace are estimated to be generated worldwide every year. However, the recovery rate of this by-product is low. Pomace is commonly disposed and thrown away as a waste, which results in environmental problems and even public health hazards. As a by-product of the apple juice processing industries, pomace contains plenty of different varieties of nutritionally important compounds, such as carbohydrates, phenolic compounds, dietary fiber and minerals. These important compounds can be recovered from apple pomace, or there is even a possibility of using apple pomace in the food systems directly or after minimal processing. Therefore, apple pomace can be utilized in food products to improve their health benefits and commercial values. This review focuses on the current food applications and influence of apple pomace on the characteristics of various food products.

Microstructure-modified products from stone-milled wheat bran powder improve glycemic response and sustain colonic fermentation

Accumulating evidence indicates carbohydrates that escape digestion from upper gastrointestinal tract can reduce glycemic response, enter the colon where they are fermented by the gut microbiota and thus exert multiple healthy benefits to host. A vertical stone milling process was used to prepare a natural wheat bran powder (SWB) containing pericarp, spermoderm, nucellar layer, aleurone layer, germ, and 15% starchy endosperm of wheat kernel, with the result that protein, amylose, and dietary fiber significantly raised comparing to wheat flour (WF). Two types of products, a powdered drink (SWB-D) and a puffed particle (SWB-P), were extruded from SWB, which underwent a gradient of gelatinization and recrystallization with progressively increased resistant starch (RS) content. Starch-protein complexes were detected in SWB-D and SWB-P, concurrently accounting for lower in vitro digestibility and human glycemic response than those of WF noodles. Intake of SWB-D and SWB-P by healthy volunteers elevated level and extended duration of breath hydrogen indicative of higher gut microbiota fermentation. Therefore, RS and starch-protein complexes formed during extrusion reduce digestibility of SWB and sustain colonic fermentation with health-promoting potential targeting the gut microbiota.

Rice-Buckwheat Gluten-Free Pasta: Effect of Processing Parameters on Quality Characteristics and Optimization of Extrusion-Cooking Process

A new type of gluten-free pasta has been developed based on a rice-buckwheat mixture. The aim of the study was to investigate the effect of process parameters of moisture content (30, 33, and 36%), barrel temperature (80, 100, and 120 °C), and screw speed (60, 80, and 100 rpm) on cooking and textural properties of rice-buckwheat pasta produced by a single-screw extrusion-cooker. The process uses response surface methodology based on a Box-Behnken experimental design. Results showed that with regard to this rice-buckwheat pasta, raising moisture content of the raw materials increased cooking loss and stickiness, but decreased firmness, while increasing barrel temperature reduced cooking loss and stickiness, but increased hardness and firmness. Screw speed increase also affected positively hardness and firmness of the obtained products. Thus, optimal conditions (moisture content 30%, barrel temperature 120 °C, and screw speed 80 rpm) were established to produce good quality rice-buckwheat pasta. At this optimum, the pasta showed a compact and homogeneous inside microstructure. Furthermore, the pasta products exhibited low cooking loss (less than 6%), good hardness and firmness, with low stickiness and acceptable scores for all sensory attributes and for overall quality.

The Winning Weaning Food (WWF): The Development of a Complementary Food for Food-Insecure Infants and Young Children in Malawi

Growing evidence exists for the benefits of adequate infant and young children feeding (IYCF) practices at the weaning stage (≥ 6 months), including optimal growth, building the immune system, cognitive development, healthy food preferences, and reduced mortality and morbidity rates. However, these outcomes are not universally experienced. To ensure that a developing country such as Malawi, where recent studies have shown high rates of food insecurity and malnutrition benefits from adequate IYCF, five nutrient-dense complementary foods (Recipes 1 to 5) were developed. Standardized food processing techniques were used in the preparation and combination of Malawian indigenous food samples. The developed food recipes were assessed for nutrient density and cultural acceptability through sensory evaluations. Recipe 5 emerged as the winning weaning food (WWF), with an overall acceptability rate of 65% (mean score of 5.82 ± 0.87). Unlike theoretical analysis with the ESHA Food Processor, statistical analysis did not show that Recipe 5 met the Codex Alimentarius recommendations for macro- and micronutrients. However, it showed that the micronutrient recommendations for iron (p = 0.0001; 95%CI) and zinc (p = 1.00; 95%CI) were partially met, but not those for calcium and vitamins A and D. The prototype and outcome of this pilot study will be invaluable for interventions aimed at combating food insecurity and malnutrition in Malawi.

Broken rice grains pregelatinized flours incorporated with lyophilized açaí pulp and the effect of extrusion on their physicochemical properties

Liophilized açaí pulp (LAP), which is considered a power food, could enrich broken rice grains flours (BRG), which is an abundant by-product in many countries. The extrusion could change the physico-chemical properties of this mixture, which later could be applied in the development of instant food products, as an appeal regarding the appearance, nutritional value and the presence of bioactive compounds. This study examined the effect of LAP incorporation (0, 5, 10, 15, and 20%) on the physical, chemical, and functional properties of BRG pregelatinized flours at mild extrusion conditions. Extrusion significantly changed the solubility and absorption of water, the thermal and pasting properties of pregelatinized flours. DSC analysis did not show gelatinization peaks after extrusion, indicating a total gelatinization of the starch. Extrusion also affected the color and chemical composition, and to a greater extent, the anthocyanin content, the phenolic compounds and the antioxidant capacity, despite the mild process conditions. The mixture with 10% LAP resulted in a product with a reddish color, rich in fiber and presented lower loss of anthocyanin (27.16%), therefore, the most suitable to be used as an ingredient in the preparation of ready-to-eat foods with higher functional value.

Effects of thermal processing on the structural and functional properties of soluble dietary fiber from whole grain oats

Normal pressure steaming, high pressure steaming, microwave, and frying are widely used to deactivate enzyme in the oats, but these thermal processing methods may affect the structural and functional properties of soluble dietary fiber, which contribute greatly to the health benefits of oat foods. The objective of this study was to evaluate the effects of four different thermal processing methods on the structural and functional properties of soluble dietary fiber from whole grain oats. The results showed that the thermal processing resulted in changes on nutritional components of whole grain oats. Especially dietary fiber components, the total dietary fiber, insoluble dietary fiber, and soluble dietary fiber content of heat-treated oats were significantly increased ( p < 0.05). Moreover, thermal processing can not only result in an increase in molecular weight and particle size, but also cause molecular aggregation and different functional properties of soluble dietary fiber. High pressure steaming-treated oat soluble dietary fiber displayed significantly higher swelling and emulsifying ( p < 0.05), but microwave-treated oat soluble dietary fiber exhibited the highest glucose, cholesterol, and sodium cholate adsorption capacities. These results might provide basic information to help to better understand the functionality of oat soluble dietary fiber and improve the process efficiency of oat foods with high nutritional qualities.

Fiber-Rich Food Processing Byproducts Enhance the Expansion of Cornstarch Extrudates

Expansion characteristics of cornstarch-based extrudates incorporating fiber-rich food processing byproducts was explored. Waxy and regular cornstarch were used as the base materials with apple pomace and sugarcane bagasse incorporated at two addition levels (0%, 15%, and 30% w/w). Extrusions were conducted at three different screw speeds (150, 200, and 250 rpm) with other parameters optimized and kept constant. Apple pomace inclusion resulted in higher initial expansion index (4.23 to 5.60) and higher stable expansion index (2.76 to 4.43), but also showed higher shrinkage (8.50% to 34.72%) than sugarcane bagasse extrudates at the same inclusion levels. Inclusion of apple pomace showed potential of producing extrudates with significantly higher expansion than cornstarch control, with relatively lower energy inputs. Extrusion methods used here have the potential to preserve the textural quality and nutritional value of the fiber-enriched extrudates, providing the base for healthier snack food items.

PRACTICAL APPLICATION

Findings from this study can be extended to the other fiber-rich food processing byproducts, such as other fruit and vegetable pomace, cereal brans, and pulse hulls among other materials. This data will help the development of fiber-enriched extruded snacks that would have favorable consumer traits.

Novel Combined Freeze-Drying and Instant Controlled Pressure Drop Drying for Restructured Carrot-Potato Chips: Optimized by Response Surface Method

Combined freeze-drying and instant controlled pressure drop process (FD-DIC) for restructured carrot-potato chips was developed and its processing conditions were optimized using response surface methodology (RSM) with the purpose of improving the quality of products and reducing energy consumption. Three critical variables including the amount of carrot, the moisture content of the partially dried product before DIC treatment, and equilibrium temperature of DIC for the restructured chips were considered. Response parameters such as the final moisture content, color value (L, a, and b), and texture properties of restructured carrot-potato chips were investigated. The results showed that the graphical optimal ranges of FD-DIC drying process were as follows: the amount of carrot was 46–54% w/w, the moisture content of the partially dried product before DIC treatment was 0.20–0.35 g/g, and the equilibrium temperature of DIC was 85–95°C. Furthermore, the numerical optimization suggested that conditions were 47.43% w/w, 0.29 g/g, and 90.57°C, respectively. It could be concluded that the combined drying method of FD-DIC provided the restructured carrot-potato chips with higher quality, as compared to the freeze-dried chips. Considering the relatively high production cost of FD, this novel FD-DIC could be an alternative method for obtaining desirable restructured fruit and vegetable chips.

The impact of extrusion on the nutritional composition, dietary fiber and in vitro digestibility of gluten-free snacks based on rice, pea and carob flour blends

Consumers and the food industry are demanding healthier products. Expanded snacks with a high nutritional value were developed from different rice, pea and carob flour blends. The proximate composition, starch (total and resistant), amylose and amylopectin, dietary fiber (soluble and insoluble) contents, and the in vitro protein digestibility of different rice-legume formulations, were evaluated before and after the extrusion process. Compared with the corresponding non-extruded blends (control), the extrusion treatment did not change the total protein content, however, it reduced the soluble protein (61-86%), the fat (69-92%) and the resistant starch contents (100%). The total starch content of all studied blends increased (2-19%) after extrusion. The processing increased the in vitro protein digestibility, reaching values around 88-95% after extrusion. Total dietary fiber was reduced around 30%, and the insoluble fraction was affected to a larger extent than the soluble fraction by the extrusion process. Because of its balanced nutritional composition, high dietary fiber content, as well as low energy density, these novel gluten-free snack-like foods could be considered as functional foods and a healthier alternative to commercially available gluten-containing or gluten-free and low nutritional value snacks.

Effect of Different Flours on the Formation of Hydroxymethylfurfural, Furfural, and Dicarbonyl Compounds in Heated Glucose/Flour Systems

Traditional cereal-based foods usually include wheat flour in their formulations; however, the search for new products with new ingredients providing different properties to foods is widely pursued by food companies. Replacement of wheat by other flours can modify both nutritional properties and organoleptic characteristics of the final baked food, but can also impact the formation of potentially harmful compounds. The effect of the type of flour on the formation of furfurals and dicarbonyl compounds was studied in a dough model system during baking that contains water or glucose in order to promote the Maillard reaction and caramelization. The formation of methylglyoxal and glyoxal was significantly reduced in spelt and teff formulations compared to wheat flour formulations, respectively. In contrast, samples formulated with oat, teff, and rye showed a significant increase in the levels of 3-deoxyglucosone. Similarly, spelt and teff formulations presented significantly higher concentrations of hydroxymethylfurfural, and spelt, teff, and rye presented higher concentrations of furfural. Therefore, the formation of process contaminants and undesirable compounds in new food products formulated with different flours replacing the traditional wheat flour should be considered carefully in terms of food safety.

Extrusion and Extruded Products: Changes in Quality Attributes as Affected by Extrusion Process Parameters: A Review

Extrusion of foods is an emerging technology for the food industries to process and market a large number of products of varying size, shape, texture, and taste. Extrusion cooking technology has led to production of wide variety of products like pasta, breakfast cereals, bread crumbs, biscuits, crackers, croutons, baby foods, snack foods, confectionery items, chewing gum, texturized vegetable protein (TVP), modified starch, pet foods, dried soups, dry beverage mixes etc. The functional properties of extruded foods plays an important role for their acceptability which include water absorption, water solubility, oil absorption indexes, expansion index, bulk density and viscosity of the dough. The aim of this review is to give the detailed outlines about the potential of extrusion technology in development of different types of products and the role of extrusion-operating conditions and their effect on product development resulting in quality changes i.e physical, chemical, and nutritional, experienced during the extrusion process.

Active polyphenolic compounds, nutrient contents and antioxidant capacity of extruded fish feed containing purple coneflower (Echinacea purpurea (L.) Moench.)

The growth of fish is directly dependent on feed composition and quality. Medicinal plants can be added to fish feed as adjuvant therapy for the prevention of fish diseases. The purple coneflower (Echinacea purpurea (L.) Moench.) has been reported to have multiple biological effects, including immunomodulatory and antioxidant activity. The most active compounds of E. purpurea are polyphenols - caffeic acid derivatives: caftaric acid, chlorogenic acid, cynarin, echinacoside and cichoric acid.

Due to a relatively limited number of studies on the use of the purple coneflower as a nutritional supplement for fish feeding, extruded fish feed with addition of Echinacea roots was produced. In the feed total phenolic content, selected polyphenol contents, the energetic value, nutrient contents and antioxidant capacity were examined.

The results indicate that fish feed with addition of the Echinacea has a great potential to be a good source of natural radical scavengers, for example polyphenols, and nutritive ingredients. Antioxidant properties of feed were well correlated with the coneflower content. The study findings confirmed that high-temperature extrusion-cooking process does not deactivate phenolic antioxidant compounds, which are present both in the Echinacea roots and in the final product. Fish feed with addition of E. purpurea can be used as a nutritional supplement in the prevention of fish diseases caused by oxidative stress.