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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.

Hypolipidemic and anti-obesity properties of extruded black, pinto and white beans were examined in male Syrian hamsters fed high fat diets for 3 weeks. The efficiency and effectiveness of extruder processing to eliminate heat-labile antinutrients were also determined. Hamsters fed a high fat diet containing 40% extruded black beans gained the same amount of weight as animals on a low-fat chow diet (based on AIN-93G). Total plasma cholesterol of the hamsters fed bean flour- based diets tended to be lower, ranging between 298 and 356 mg/dL, compared to 365 mg/dL for the control group and total and free liver cholesterol was about 50 and 33% lower, respectively, in the livers (freeze-dried) of hamsters fed the black turtle bean (BB) and pinto bean (PB) diets. The nitrogen content of the feces from hamsters fed the PB and white bean (WB) diets were 2.6x higher than the control and the excretion of deoxycholic acid (DCA) and lithocholic acid (LCA) was higher in all legume fed hamsters The results show that extrusion efficiently and economically reduces anti-nutritive factors that inhibit the digestion and absorption of proteins and carbohydrates.Graphical abstract

The aim of this study was to improve storage characteristics of brown rice by using infrared radiation drying (IRD) through comparison with hot air drying (HAD) and ambient air drying (AAD). After heating by IR from 20 °C to 60 °C within 58 s, 2.17 percentage points moisture of rough rice (initial moisture content is 25.0 ± 0.2% in dry basis) were removed without adverse effect on germination capacity of husked brown rice. Compared with AAD, IRD slowed down the increase in yellowness, water uptake and volume expansion ratio of brown rice by 47.9%, 41.0% and 37.9% after four months of storage, and decreased the temperature range and enthalpy of gelatinization, the peak and breakdown viscosities. These changes might due to the higher stabilization effect of IRD on the microstructure and thermal properties of proteins and starch granules than AAD. IRD is an effective method to improve storage stability of brown rice.

espanolEn este estudio se formularon novedosas mezclas de harina a partir de la cascara de maracuya y de arroz. Empleando un extrusor de tornillo unico, dichas mezclas se transformaron en piezas extruidas con valor agregado. Utilizando un diseno central compuesto se evaluaron los efectos de las variables propias de la extrusion —temperatura del troquel, humedad del material alimentado y contenido de la cascara de maracuya— en la expansion seccional (SEI), la expansion longitudinal (LEI), la absorcion de agua (WAI) y los indice de hidrosolubilidad (WSI) de las piezas extruidas. Se constato que las variables vinculadas con el procesamiento incidieron de manera marcada en todas las variables independientes estudiadas (SEI, LEI, WAI y WSI). Las cascaras de maracuya utilizadas en este estudio contaban con 56.76% de fibra cruda. Ademas, la imagen microestructural de las areas transversales, las estructuras internas y la apariencia superficial del material extruido con un contenido de 0-15% de la cascara de maracuya en su formulacion da cuenta de que la adicion de la cascara de maracuya produjo la disminucion de la expansion y el tamano de las celulas, aumento el grosor de la pared de las celulas de aire y les dio mayor apariencia de tener superficie aspera. El presente estudio demostro la utilidad que conlleva desarrollar materiales extruidos ricos en fibras obtenidas del arroz y de la cascara de maracuya. EnglishNovel formulations of passion fruit shell flour and rice blends were processed on a single-screw extruder, into value-added extrudates. The effects of extrusion processing variables of die temperature, feed moisture, and passion fruit shell flour content on the sectional expansion (SEI), longitudinal expansion (LEI), water absorption (WAI), and water solubility (WSI) indices of the extrudates were evaluated using a central composite design. The processing variables caused a marked effect on all the independent variables studied (SEI, LEI, WAI, and WSI). Passion fruit shell flour used in this study contained 56.76% of crude fiber. Additionally, the microstructural view of the cross-sectional areas, internal structure and surface appearance of extrudates containing 0–15% passion fruit shell flour in their formulation revealed that the addition of passion fruit shell flour led to a decrease in expansion and cell size, increase in thickness of air cell wall and rough surface appearance. This study demonstrated the usefulness of developing extruded rich in fiber from rice and passion fruit shell flour.

Pulses are well known to be gluten-free functional foods that provide a rich source of nutritional and healthy compounds with antioxidant-promoting activity. In the present study, the bioactive compounds, dietary fibre, arabinoxylans, individual phenolic compounds and tocopherols, were evaluated in different lentil flours (raw and extruded at 140 and 160 °C) formulated with nutritional yeasts, along with the changes induced by the extrusion process. The total dietary fibre and arabinoxylan content significantly (p < 0.05) increased after the extrusion process while a significant decrease of all tocopherol isoforms was also observed. Catechin, caffeic, kaempferol and quercetin derivatives were identified in the raw and extruded lentil flours. The decreases of total phenolic and individual phenolic compounds were directly related to the extrusion temperature; total phenolics and catechin hexoside exhibited a larger decrease in the lentil flours formulated with higher content of nutritional yeast (12 and 16%). The antioxidant activity results, determined using different assays, reflected the important effect of extrusion processing and food ingredients. The authors are grateful to the ALIMNOVA research group (UCM-951505/2012) and to the Foundation for Science and Technology (FCT, Portugal) and FEDER under Program PT2020 for financial support to CIMO (UID/AGR/00690/2013) and L. Barros (SFRH/BPD/107855/2015) and for the grant POCI-01- 0145-FEDER-006984 (LA LSRE-LCM), funded by FEDER, through POCI-COMPETE2020 and FCT. info:eu-repo/semantics/publishedVersion

El objetivo de esta investigación fue evaluar el efecto de la germinación sobre el contenido de compuestos fenólicos, isoflavonas y actividad antioxidante de extractos de soya obtenidos a partir de semillas germinadas por 2 y 6 días. Después de 6 días de germinación, el contenido de la mayoría de los compuestos fenólicos, incluyendo las isoflavonas, aumentó significativamente en comparación con el de las muestras de soya no germinada y la soya germinada por 2 días. Los compuestos fenólicos libres, los ácidos benzoico y vanílico, disminuyeron durante el proceso de germinación. La actividad antioxidante de la soya aumentó con el tiempo de germinación, y se observó una alta correlación entre los compuestos fenólicos totales (TPCs), la actividad antioxidante Trolox equivalente (TEAC) y el poder antioxidante reductor férrico (FRAP). Las isoflavonas también mostraron altas correlaciones con los ensayos TEAC y FRAP, y sólo la glicitina mostró correlaciones relativamente bajas. El proceso de germinación permitió aumentos en compuestos fenólicos bioactivos e isoflavona aglicona. Estos efectos mejoraron las propiedades funcionales de la soya. The objective of this research was to evaluate the effect of germination on the content of phenolic compounds, isoflavones and antioxidant activity of soybean extracts obtained from ungerminated soybeans and those germinated for 2 and 6 days. After 6 days of germination, the content of most phenolics, including isoflavones, significantly increased compared with that of samples from ungerminated soybeans and soybeans germinated for 2 days. The free phenolic compounds, benzoic and vanillic acids, decreased during the germination process. The antioxidant activity of the soybeans increased with germination time, and a high correlation was observed among total phenolic contents (TPCs), Trolox equivalent antioxidant activity (TEAC) and ferric reducing antioxidant power (FRAP). Isoflavones also showed high correlations with TEAC and FRAP assays, and only glycitin showed relatively low correlations. The process of germination allowed for increases in bioactive phenolic compounds and isoflavone aglycon. These effects enhanced the functional properties of the soybean.

Tiger nut (TN) is a nutritious source of gluten-free flour, used generally in healthy beverages, but its incorporation in gluten-free extruded snacks has not been explored. TN flour was blended at different concentrations (up to 70%) with rice flour and soluble fiber, for the development of gluten-free snacks on a twin-screw extruder. The effect of TN inclusion in the formulations was evaluated on relevant physiochemical characteristics of the snacks. Viscoamylograph of the raw formulations showed that TN addition increased (p < 0.01) onset temperature and delayed peak viscosity. In the extruded flours, TN contributed to limit the starch degradation during extrusion. Diameter, expansion ratio, true density, and total pore volume of the extrudates were reduced (pf < 0.01) by the increased TN content in the formulations, while bulk density rose. The surfaces of the extruded snacks were modified by the increasing inclusion of TN in substitution of rice in the formulations. Extrudates containing 10% TN showed the best overall texture profile. Moreover, TN addition enhanced the ash and protein content of the snacks and increased their total antioxidant activity. This study demonstrated that incorporation of 10% TN flour into rice-based formulation was suitable for making gluten-free snacks with acceptable physical properties., This research was funded by MINISTRY OF SCIENCE, INNOVATION AND UNIVERSITIES (Project RTI2018-095919-B-C21), the EUROPEAN REGIONAL DEVELOPMENT FUND (FEDER) and GENERALITAT VALENCIANA for financial support (Prometeo 2017/189). N. Gasparre thanks to GENERALITAT VALENCIANA for his predoctoral fellowship Santiago Grisolia (P/2017-104) and his mobility grant (BEFPI/2019/003).

The objective of this study was to evaluate the effects of starch source and amylose content on the expansion ratio, density, and texture of expanded extrudates, as well as to investigate the structural and molecular changes that occur in starch granules as a function of extrusion. The starches employed were rice starches (8%, 20%, and 32% amylose), carioca bean starch (35% amylose), and Hylon V® corn starch (55% amylose). The extrudates from rice starches containing 20% and 32% amylose exhibited the highest expansion ratio, while, extrudates from Hylon V® corn starch containing 55% amylose exhibited the lowest expansion ratio. The hardness values of the extrudates with 55% amylose were twice those of the extrudates with 20%, 32%, and 35% amylose. An additional finding was that although the amylopectin promoted the expansion of the gelatinized starch matrix, it failed to strengthen and sustain the walls of the extrudate bubbles during expansion.

Microbial contamination and mold growth are common causes of strawberry deterioration during storage. The growing need for extending shelf-life while enhancing the overall quality of perishable fruits has generated increasing interest in the development of novel preservation technologies. This study used electrostatic spraying (ES) technology as an innovative and efficient technique for the application of edible alginate coating enriched with carvacrol and methyl cinnamate (natural antimicrobials) on fresh strawberries. The efficiency of the electrostatic technology was compared to non-electrostatic (conventional) spray (NES) technology in terms of transfer efficiency and coating evenness. Furthermore, physicochemical and textural parameters (such as weight loss, visible decay, firmness, surface color, total soluble phenolic content, and antioxidant capacity) of ES and NES coated fruits were studied and compared to uncoated controls. ES technology demonstrated higher transfer efficiency and evenness than NES, which led to a significant reduction of visible decay over uncoated controls. The delay in microbial spoilage by ES (11 days) was greater than by NES (10 days) and uncoated strawberries (7 days). ES coating significantly inhibited strawberry decay with only 5.6 % of infected fruits, compared to 16.6 and 8.3 % for control and NES fruits after 13 days of storage, respectively. At the end of 13 days of storage, ES coating demonstrated superior performance on strawberry firmness, color retention, and weight loss reduction. Additionally, no differences were observed between uncoated and coated fruits with regard to their antioxidant and total soluble phenolics.

This study aimed to develop and characterize biodegradable films containing mucilage, chitosan and polyvinyl alcohol (PVA) in different concentrations. The films were prepared by casting on glass plates using glycerol as plasticizer. Mechanical properties, water vapor and oxygen barrier, as well as the interaction with water, were measured. The compatibility of the film-forming components and the uniformity of the films were determined by zeta potential and SEM, respectively. The glycerol and mucilage allowed obtaining more hydrophilic films. The barrier properties of the films made from 100 % chitosan were similar to composed films containing PVA up to 40 %. The results of this study suggest that the interaction between chitosan and mucilage could increase water vapor permeability. The films prepared from either 100 % chitosan or PVA showed a more hydrophobic behavior as compared to the composed films. The films were homogenous since no boundary or separation of components was observed, indicating a good compatibility of the components in the films.

The food industry is increasingly innovating and applying new processing technologies and ingredients to develop novel food products that meet the consumers’ demand. In this study, the effect of extrusion (at 140 °C and 160 °C) was evaluated in different lentil flours formulations enriched with nutritional yeast, in terms of α-galactosides (raffinose, stachyose, verbascose), inositol phosphates (IPs), trypsin inhibitors and lectins content. The content of α-galactosides and IPs was determined by high performance liquid chromatography. Trypsin inhibitor activity (TIA) was evaluated using a small-scale quantitative assay. The lectin content was analyzed using a haemagglutination assay and a Competitive Indirect Enzyme-linked immunosorbent assay. Extrusion promoted a significant increase, up to 85% in total α-galactosides content. After extrusion, IPs content was significantly decreased and TIA as well as lectins content had a reduction higher than 90%. Extrusion demonstrated to have a beneficial effect by increasing desirable prebiotic compounds and decreasing non-nutritional factors.

Infrared radiation heating has a promising potential in improving drying rate and food safety, but its effect on the storage stability of rough rice is not known. The objective of this study was to develop an infrared drying (IRD) method to improve the storage stability of rough rice during storage. The effects of IRD on the physicochemical properties of stored rough rice were compared with those of hot air drying (HAD) and ambient air drying (AAD). Freshly harvested M206 rice was dried to a targeted moisture content of 16 % (d.b.) by using IRD, HAD, and AAD. The dried rice samples were then stored at 35.0 ± 1.0 °C and a relative humidity of 65.0 ± 3.0 % for up to 10 months. The physicochemical and cooking properties of rice samples were periodically determined over the storage duration. Compared with AAD, the yellowness index, water uptake, and volume expansion ratio of the rough rice dried with IRD and stored for 4 months were reduced by 26.3, 76.3, and 14.5 %, respectively. After 10 months of storage, the change in hardness of cooked IR-dried rice was significantly reduced by 22 % compared to that of samples dried with AAD. IRD likely caused a slight denaturation of protein and annealing of starch that was located on the surface layer of rice kernels, resulting in decreased gelatinization temperature, enthalpy, and viscosity, and reduced the changes in microstructure, but retained cooking characteristics after storage. Therefore, IRD is recommended as a promising technique that achieves high rice drying efficiency and improved storage stability.

This study aims to evaluate the effects of polishing and parboiling on proximate composition, structure, phenolic compounds, antioxidant activity, cooking time and hardness of IAC-600 black rice cultivar and MPB-10 red rice lineage. Proximate analysis and light micrographs revealed higher migration of red rice proteins than black rice proteins to the endosperm as a result of parboiling. Parboiling reduced the ash content of red rice while no difference was determined in black rice. Gelatinized starch granules from both genotypes showed similar appearance. There was a decrease in relative crystallinity on both black and red rice subjected to parboiling, which was an indicative of crystallites disruption. Polishing removed more than 90% of free phenolics for both genotypes, while parboiling allowed the partial preservation of free phenolics content in polished rice. Parboiling induced an increase in the cooking time of red rice, but a decrease in the cooking time of black rice.

Extrusion process has been generally applied to the production of cereal-based snacks. However, in recent years, extrusion process has been also used for the development of pulses-based snacks, with few studies focussing on the incorporation of these food ingredients to obtain bioactive compounds enriched snacks with acceptable quality. The effects of the extrusion processing on fiber (soluble and insoluble), total available carbohydrates, tocopherols, organic acids, total phenolics, hydroxycinnamic acids, hydroxybenzoic acids and flavonols, as well as on the antioxidant capacity of different lentil-based, fiber-enriched flours were evaluated. Total dietary fiber (TDF) in the extruded flours ranged between 7.49 and 10.22 g/100 g, with a decrease from 6 to 37% which correlated with a significant increase in the fiber soluble fraction. α-, γ- and δ-Tocopherols were characterized in all the analyzed samples, being γ-tocopherol the major isoform, before and after extrusion. Additionally, a marked decrease of 83 to 94% in total tocopherol content after extrusion processing was observed and the decrease was more significant on quinic acid content. Conversely, an increase in most polyphenolic fractions was observed, probably due to the effect of extrusion process to induce hydrolysis of polyphenols bound fiber and/or proteins moieties, changing from non-extractable to extractable polyphenols. Similar increase in antioxidant activity was also observed in most formulated lentil-based flours, measured by four different antioxidant assays. Only flavonols presented an extensive content decrease of about 62 to 82%, after extrusion treatment. The authors are grateful to ALIMNOVA research group (UCM-GR35/10A) and to the CIMO research centre (Pest-OE/AGR/UI0690/2014) for financial support, and L. Barros’ research contract (“Compromisso para a Ciência 2008”).

The objective of this work was to study the effect of enzymatic hydrolysis of black bean protein concentrate using different enzymes. Bean proteins were extracted and hydrolyzed over a period of 120 min using the enzymes pepsin or alcalase. The protein hydrolysates’ molecular weight was assayed by electrophoresis and the antioxidant activity was evaluated by the capturing methods of free radicals ABTS●+ and DPPH. Electrophoretic results showed that the bands above 50 kDa disappeared, when the beans protein was subjected to hydrolysis with pepsin. The bean protein hydrolysate obtained by hydrolysis with alcalase enzyme, showed higher antioxidant activity for inhibition of the radical ABTS●+. However, the hydrolysates obtained by hydrolysis with pepsin had higher antioxidant activity for inhibition of the radical DPPH. The use of pepsin and alcalase enzymes, under the same reaction time, produced black bean protein hydrolysates with different molecular weight profiles and superior antioxidant activity than the native bean protein.

abuticaba (Myrciaria cauliflora. Mart) is a highly perishable fruit native to Brazil, which is consumed both fresh and industrially processed in the form of juices, jams, wines and distilled liqueurs. This processing generates a large amount of waste by-products, which represent approximately 50% of the fruit weight. The by-products are of interest for obtaining valuable bioactive compounds that could be used as nutraceuticals or functional ingredients. In this study, fermented and non-fermented jabuticaba pomaces were studied regarding their hydrophilic and lipophilic compounds, as well as their antioxidant properties, including: soluble sugars, organic acids and tocopherols (using high performance liquid chromatography coupled to refraction index, diode array and fluorescence detector, respectively); phenolics and anthocyanins, (using liquid chromatography coupled to diode array detection, and mass spectrometry with electrospray ionization); and fatty acids (using gas-liquid chromatography with flame ionization detection). The analytical data demonstrated that jabuticaba pomaces are a rich source of bioactive compounds such as tocopherols, polyunsaturated fatty acids and phenolic compounds (namely hydrolyzable tannins and anthocyanins) with antioxidant potential. Therefore, jabuticaba pomace may have good potential as a functional ingredient in the fabrication of human foods and animal feed. The authors are grateful to the Foundation for Science and Technology (Portugal) for financial support to CIMO (strategic project Pest-OE/AGR/UI0690/2011) and to L. Barros (researcher contract under “Programa Compromisso com Ciência-2008”).