Functional and thermorheological properties of rice flour gels for gluten-free pasta applications

Based on the European Commission directives on circular economy, this work explores the functional and thermorheological properties of rice flour from broken kernels, a by-product from the rice industry, in order to evaluate its possible use in food applications, back into the value chain. Chemical and hydration properties of two rice varieties (Guiana – Indica spp, Ariete – Japonica spp) were accessed, as well as the impact of the rice variety on the texture and viscoelasticity of rice flour gels (6–26%). Both rice varieties presented statistically different physicochemical properties (protein, lipid and amylose contents), and hydration properties that support the distinct texture and rheology behaviour of gels obtained. Rheology results suggested the formation of a gel-network structure with high frequency dependence, especially at lower rice concentrations. Texture results suggest that both rice varieties could be suited for development of gluten-free products that require pre-gelatinised starch, such as pasta. The effect of gelatinised rice flour (10–25%) and gelatinised flour/rice flour ratio (40:60, 50:50, 60:40) on the physical properties and cooking quality of pasta were assessed. Better overall cooking quality and texture properties were obtained for the formulation with 20% gelatinised rice flour and 50:50 rice gel:rice flour ratioinfo:eu-repo/semantics/publishedVersio

Psyllium and Laminaria partnership - An overview of possible food gel applications

Featured Application: Laminaria-psyllium gels with distinct texture and rheological features, designed for a wide range of food applicationsSeaweeds are a novel source of important nutritional compounds with interesting biological activities that could be processed into added-value products. In this study, two previously developed products obtained by Laminaria ochroleuca processing (liquid extract and a purée-like mixture) were processed with Psyllium gel to develop functional hydrogels. The optimization of the formulation and the characterization of the Laminaria-Psyllium gels in terms of their mechanical features have allowed the proposal of potential food applications. A beneficial interaction was found between Laminaria and Psyllium in terms of the reinforcement of texture and rheological properties. The obtained outcomes could provide new healthy gelling formulations with attractive properties to alleviate the growing market demand of eco-novel food matricesinfo:eu-repo/semantics/publishedVersio

Gluten-free fresh pasta enriched with bioactive compounds

Doutoramento em Engenharia Alimentar / Instituto Superior de Agronomia. Universidade de LisboaSustainability of the agri-food chain is on today’s agenda, whether through the use of industrial byproducts or the investigation of alternative sources of ingredients. The increasing number of individuals with gluten-related diseases, but also consumers following a gluten-free diet are the drivers for the continually growing number of gluten-free products launched in the market. However, in addition to their still limited commercial availability and high price compared to their wheat counterparts, gluten-free products show nutritional deficiencies. Following the current consumer trends for healthy foods with underlying sustainable principles (ingredients and processes), this thesis aimed the development of a gluten-free fresh pasta based on rice flour from broken grains and Psyllium husk, enriched with Arthrospira platensis, Laminaria ochroleuca and potato peel. Firstly, the gelatinisation (5 – 26%) of rice flour from broken rice (rice processing industry by-product) was performed to assess the optimum conditions for producing gluten-free pasta. Afterwards, the pasta formulation (50% gelatinised rice flour/rice flour) was successfully optimized, and its structure reinforced with 4% Psyllium husk gel. This gluten-free pasta was then enriched with bioactive compound sources (Arthrospira platensis, Laminaria ochroleuca and potato peel) incorporated as lyophilised biomass, gel or liquid extract obtained by subcritical water extraction (autohydrolysis), an eco-friendly technology. The pastas developed were characterized in terms of cooking quality parameters, texture, colour, rheology, nutritional composition, antioxidant activity, in vitro digestibility and sensory analysis. It was found that autohydrolysis was a suitable technology for the valorisation of distinct materials, namely marine and industrial. Pastas with Laminaria ochroleuca provided a high mineral and fibre contents, and low-fat content, so that could bear nutritional claims. On the other hand, Arthrospira platensis incorporation proved to have a positive effect on the pasta antioxidant activity and overall sensory analysis without affecting the in vitro digestibility. Pasta with potato peel extract presented a high total phenolic content and antioxidant activity. All formulations presented good overall cooking quality and texture and rheology propertiesN/

Biorefinery concept for discarded potatoes: Recovery of starch and bioactive compounds

The integral valorisation of discarding potatoes from three local varieties using processes of low environmental impact to recover the starch contained in the flesh as well as the bioactive compounds present in the skin or in the processing wastewaters was studied. The remaining flesh after starch extraction was also recovered to further processing. The extraction of starch and active extracts using environmentally friendly technologies, the physicochemical and phytochemical characterisation of the extracts, the formulation and mechanical characterisation of the corresponding functional hydrogels, have allowed proposing potential food and non-food applications. Results indicated that subcritical water extraction (220 ºC) was an efficient technology to recover antioxidants from the potato skin. Processing wastewaters exhibited high protein content. The extracted starch featured comparable physicochemical properties to that available commercially and the corresponding hydrogels exhibited enhanced mechanical properties with absence of syneresis. It should be remarked that Agria and Neiker varieties provided the highest total starch and bioactive content in terms of phenolics, TEAC value and DPPH inhibition percentage, respectivelyinfo:eu-repo/semantics/publishedVersio

Edible brown seaweed in gluten-free pasta: technological and nutritional evaluation

Seaweed is a novel source of important nutritional compounds with interesting biological activities that could be processed into added-value products, namely gluten-free foods. In this study, two previously developed products obtained from Laminaria ochroleuca processing (liquid extract and a purée-like mixture) were incorporated in gluten-free (GF) pasta in order to develop functional products especially designed for the celiac population. The raw and cooked pastas were characterized in terms of their cooking quality parameters, nutritional composition, texture and rheological properties, and antioxidant activity. It was found that the developed GF pastas had similar mechanical and texture characteristics to the control. Both supplemented GF pastas presented a significantly (p < 0.05) higher fibre and mineral content than the control pastainfo:eu-repo/semantics/publishedVersio

Environmentally friendly processing of Laminaria ochroleuca for soft food applications with bioactive properties

Dehydrated Laminaria ochroleuca was processed by autohydrolysis with compressed hot water to extract bioactive compounds. Both the whole algae and individual fractions obtained (solid residue and liquor) were characterised to assess its functional properties for future innovative food applications. Purée-like systems were developed by combining ultrasonic and thermal technologies to maximise the antioxidant capacity and were evaluated by determining colour, texture, rheology, syneresis and the presence of bioactive compounds. Overall, the obtained results indicated that L. ochroleuca is a valuable resource that can be used as a whole or taking advantage of its bioactive fractions, in a concept of circular economy and sustainabilityinfo:eu-repo/semantics/publishedVersio

Improving the nutritional performance of gluten-free pasta with potato peel autohydrolysis extract

The potato processing industry produces peels, a good source of fibres, minerals and antioxidants, which could be recovered and used in the production of added-value products, such as gluten-free (GF) foods especially designed for the celiac population. This work is focused on the application of the bioactive fraction extracted from potato peels into GF pasta. Subcritical water extraction (autohydrolysis, AH) was performed on potato peel, and the obtained AH liquid extract was characterized in terms of total phenolic content and antioxidant activity. The selected AH temperature (220 °C at 2.2 MPa) was applied to peels from Kennebec, Neiker and Agria potato varieties, and the Agria extract was selected for application in GF pasta, as this was the one with higher antioxidant activity. The impact of Agria potato peel autohydrolysis extract on the nutritional composition and cooking quality of pasta was assessed. Results confirmed that the GF pasta enriched with potato peel extract presented suitable technological properties, coupled with attractive colour and with increased total phenolic content and antioxidant activity, which can contribute to improve the offer of GF products in the marketinfo:eu-repo/semantics/publishedVersio

Paddy rice stored under hermetic conditions: the effect of relative humidity, temperature and storage time in suppressing Sitophilus zeamais and impact on rice quality

The aim of this study was to analyse the effect of relative humidity in suppressing Sitophilus zeamais, in paddy rice stored under hermetic conditions, during four and seven months, at different average temperatures, as well as the impact on rice quality. Hermetic bags, GrainPro® SuperGrainbag® Farm™, were used to store two rice varieties under three different relative humidities: 67%, 75% and 85% RH, and average temperatures of 14 C, 17 C and 24 C, both monitored by Hobo® Data loggers, with the probe placed inside the bags. CheckpointII Portable O2 and CO2 Gas Analyzer was used to assess gas contents on the top and bottom of each bag. At the end of the trials, paddy samples were collected to estimate water activity (aw). The rheology behaviour of rice pastes prepared with race flour obtained from the different treatments was also evaluated, using a controlled stress rheometer. The results showed that the response of the stored-product insects changes with environmental conditions, O2 and CO2 contents. Other parameters were considered; aw increased with relative humidity and temperature, but decreased with storage time. The relative humidity played an important role, together with the increase of temperature, in suppressing insect populations. A modified atmosphere was naturally produced inside the hermetic bag, under 85% RH, with low O2 and high CO2 contents, at different average temperatures, 14 C and 17 C. These results demonstrated that S. zeamais can survive, but has no progeny. Under the same conditions, but at the higher average temperature of 24 C, S. zeamais attained 100% mortality before producing progeny. The increase on respiration rate, registered by CO2 increase and O2 decrease, for higher RH values, reduced the viscoelastic functions and changed the starch gelatinization point of Indica and Japonica rice. The results obtained showed that storing paddy hermetically, at low relative humidity, did not change atmospheric content and maintained the viscoelastic functions of the rice pastesinfo:eu-repo/semantics/publishedVersio

Effect of Arthrospira platensis (spirulina) incorporation on the rheological and bioactive properties of gluten-free fresh pasta

Gluten-free foods are generally nutritionally deficient and are the source of serious technological constraints. This work aimed to evaluate the technological performance of addition of two spirulina biomasses: Arthrospira platensis F&M-C256 and Ox Nature (resulting from different drying procedures) to gluten-free pastas, in terms of mechanical properties, antioxidant capacity, in vitro digestibility and sensory analysis. Texture properties of GF pasta was not significantly (p < 0.05) altered by the incorporation of A. platensis biomass. The different drying methods applied to A. platensis biomasses had an impact on the bioactive compounds and the in vitro digestibility of the gluten-free pastas. Both A. platensis biomasses provided a significant (p < 0.05) supplementation of phenolic compounds, chlorophylls and carotenoids to the gluten-free pastas, that resulted in significantly (p < 0.05) higher antioxidant activity when compared to control (without A. platensis) and wheat pasta. Between the new gluten-free developed pastas, consumers preferred the one supplemented with 2% A. platensis F&M-C256 biomass. Knowing the contribution of A. platensis biomass addition on pasta properties is fundamental to extend the utilization of this cyanobacterium for novel foods development. These results indicate that A. platensis biomass is a suitable ingredient to enhance the nutritional quality of pasta, without affecting its cooking and texture quality properties, with a favourable sensory evaluationinfo:eu-repo/semantics/publishedVersio

Pasta enrichment with an Amaranth hydrolysate affects the overall acceptability while maintaining antihypertensive properties

Background: Alcalase-treated amaranth proteins generate angiotensin-1-converting enzyme (ACE-1) inhibitory peptides, which could be useful for functional foods development. Our aim was to evaluate the technological, sensory, and antihypertensive properties of pasta enriched with an amaranth hydrolysate. Methods: Pasta with 11% (A; control), 15% (B), and 20% (C) of protein content were formulated. Pastas B and C were supplemented with an alcalase-treated amaranth protein concentrate. Cooking time, cooking lost, color, and texture were assessed. An untrained panel (n = 30) evaluated sensory attributes. The antihypertensive e ect was evaluated in hypertensive rats. Results: The hydrolysate IC50 was 0.014 mg/mL. Optimum cooking time and cooking loss decreased in products B and C vs. A (p < 0.05). The L* values decreased in pasta C. Firmness increased in pasta C vs. A (p < 0.05). Adhesiveness was di erent among groups (p < 0.05). Pasta A had the highest acceptability (p < 0.05). The products B and C, and captopril (positive control) showed antihypertensive properties after 3 h of supplementation (p < 0.05). This e ect remained after 7 h, 8 h, or 9 h. Conclusions: The addition of amaranth hydrolysates to pasta negatively impacts on the overall acceptability and, to a lesser extent, on pasta taste. However, it is possible to maintain the antihypertensive properties of the supplemented pasta under physiological conditionsinfo:eu-repo/semantics/publishedVersio