•Bio-refineries are an adequate framework to process organic waste materials.•Spent coffee grounds can be completely utilized in a bio-refinery to obtain high-value products.•A full set of high value ...products, biofuels and bioenergy can be obtained in a SCG bio-refinery.•Significant challenges still exist to develop and implement waste based bio-refineries.
Although normally seen as a problem, current policies and strategic plans concur that if adequately managed, waste can be a source of the most interesting and valuable products, among which metals, oils and fats, lignin, cellulose and hemicelluloses, tannins, antioxidants, caffeine, polyphenols, pigments, flavonoids, through recycling, compound recovery or energy valorization, following the waste hierarchy. Besides contributing to more sustainable and circular economies, those products also have high commercial value when compared to the ones obtained by currently used waste treatment methods. In this paper, it is shown how the bio-refinery framework can be used to obtain high value products from organic waste. With spent coffee grounds as a case study, a sequential process is used to obtain first the most valuable, and then other products, allowing proper valorization of residues and increased sustainability of the whole process. Challenges facing full development and implementation of waste based bio-refineries are highlighted.
Sustainable production of renewable energy is being hotly debated globally since it is increasingly understood that first generation biofuels, primarily produced from food crops and mostly oil seeds ...are limited in their ability to achieve targets for biofuel production, climate change mitigation and economic growth. These concerns have increased the interest in developing second generation biofuels produced from non-food feedstocks such as microalgae, which potentially offer greatest opportunities in the longer term. This paper reviews the current status of microalgae use for biodiesel production, including their cultivation, harvesting, and processing. The microalgae species most used for biodiesel production are presented and their main advantages described in comparison with other available biodiesel feedstocks. The various aspects associated with the design of microalgae production units are described, giving an overview of the current state of development of algae cultivation systems (photo-bioreactors and open ponds). Other potential applications and products from microalgae are also presented such as for biological sequestration of CO
2, wastewater treatment, in human health, as food additive, and for aquaculture.
The scientific and industrial communities have been giving great attention to the development of new bio-based materials with potential use in innovative technological applications. Among these ...materials are the structures with gel-like behavior that can be used in the cosmetic, pharmaceutical and food industries, aiming at controlling the physical properties of the final products. In the past ten years, words like oleogels and organogels have been increasingly used, the existing number of manuscripts and patents being proof of this tendency. In the food industry, oleogels can be used to control phase separation, and decrease the mobility and migration of the oil phase, providing solid-like properties without using high levels of saturated fatty acids as well as to be a carrier of bioactive compounds. In most cases, their main features are related to the reorganization process of gelators after an increase of the temperature, above the melting or glass transition temperature of the materials, known as the direct method, but it is also possible to develop oleogels by indirect methods, such as emulsification and the solvent exchange technique. In the direct methods, the reorganization is able to physically entrap oil leading to different physicochemical properties, the rheological behavior and texture properties being the frequently most studied ones. This review overviews the use of food grade and bio-based structurants to produce edible oleogels, aiming at fat replacement and structure-tailoring. Gelation mechanisms and oil phases used during oleogel production are discussed, as well as the current food applications and future trends for this kind of structure.
The number of publications, as a result of searching for hydrogels and oleogels for food applications in the last 10 years, shows that oleogels are getting more attention while hydrogels remain as a topic of interest. Moreover, the increasing number of publications dealing with food and obesity reveals that the food industry still has an important role in this regard.
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•P. tricornutum cultivated under natural conditions in Chile was characterized.•Real process data was used to scale-up the biorefinery scenarios.•Three P. tricornutum based ...biorefinery process configurations were proposed.•Integrated biorefinery for biofuels and high-value compounds revealed advantageous.
Microalgae are a rich source of proteins, carbohydrates and lipids, among other components, and thus, are considered to be the next generation biomass. However, in order to enhance the economic viability of its industrial production, all biomass components need to be valorized, requiring a multi-product biorefinery. Thus, this work proposes and conceptually analyses biorefinery processes for valorizing Phaeodactylum tricornutum for biofuels and high-value compounds, based on real data from a pilot-scale process. The algal biomass was biochemically characterized and the production was scaled-up to an industrial approach to analyze three biorefinery configurations, based on a 18 ton·year−1 of microalga biomass. The biomass revealed a composition of 7.85 wt% carbohydrates, 38.40 wt% proteins, 9.08 wt% lipids, 0.86 wt% fucoxanthin and 5.19 wt% biosilica. The biorefinery process addressed for biofuels production has an estimated annual production of 1.72, 0.35 and 1361 m3·year−1 of respectively biodiesel, bioethanol and biomethane. The biorefinery addressed for high-value compounds yields 0.18, 0.93 and 6.95 ton·year−1 of respectively fucoxanthin, biosilica and protein. The biorefinery designed for valorizing full microalgae biomass, showed to be more beneficial for promoting a circular economy. Biorefinery approach is useful for making sound and profitable decisions regarding microalgae bioproducts.
Aiming at the enhancement of food products' nutritional and health value, the incorporation of nutraceuticals has attracted increasing interest in the last years. However, they often exhibit low ...water solubility and stability, limiting their direct incorporation into food products. Also, they show very low bioavailability due to limited bioaccessibility, poor absorption and/or chemical transformation within the gastrointestinal tract. This renders their health benefits extremely difficult to be realized by the consumers.
In the present review the recent innovations regarding the formulation and design of bio-based micro and nano-delivery systems to encapsulate nutraceuticals is discussed; it also gives an overview of the challenges associated to their development; and highlights some strategies to enhance nutraceuticals' bioavailability. An insight about delivery systems' potential toxicity (in particular at nano-scale) is also provided.
Recent developments in the design of bio-based delivery systems offer the possibility of stabilizing and enhancing nutraceuticals' functionality within food products. In fact, different strategies can be used to enhance nutraceuticals' bioavailability: i) nano-delivery systems, besides showing a huge potential for the protection of valuable nutraceuticals during food processing/digestion, can be used to increase their bioavailability; ii) absorption enhancement technologies have been successfully used to increase nutraceuticals' membrane permeation; and iii) excipient foods have been shown to improve nutraceuticals' biological activity. However, the application of these enabling technologies to food is hindered by very pertinent issues that can be summarized in the effective preservation/maximization of the nutraceuticals' bioactivity and safety, once inside the human body.
•Delivery systems allow nutraceuticals' protection and their incorporation in foods.•Bio-based delivery systems can be specifically designed to enhance nutraceuticals' bioavailability.•Bioavailability enhancement strategies include nano-delivery systems, absorption enhancers and excipient foods.•It is crucial to evaluate the safety of nano-delivery systems in food.•Development of delivery systems that provide nutraceuticals' greatest functionality and safety remains a challenge.
Hydrocolloids from seaweeds have interesting functional properties, such as antioxidant activity and gelling ability. A polysaccharide was isolated by aqueous extraction at 90
°C from the red seaweed
...Gracilaria birdiae (
Gb), with a yield of 27.2% of the seaweed dry weight. The sulfate content of the polysaccharide was 8.4% and the main sugars present were galactose (65.4
mol%), 3,6-anhydrogalactose (25.1
mol%) and 6-
O-methylgalactose (9.2
mol%). Gel permeation chromatography showed that
Gb polysaccharide is a heterogeneous system, with molar mass at the main peak of 3.7
×
10
5
g
mol
−1 and a shoulder of 2.6
×
10
6
g
mol
−1. The sulfated polysaccharide of
Gb characterized by FTIR exhibits the characteristic bands of agarocolloids (at 1375 and 770
cm
−1).
The rheological behavior of
Gb sulfated polysaccharide exhibits a gel-like behavior close to the one observed in commercial agar.
The antioxidant properties of
Gb sulfated polysaccharide were evaluated by measuring DPPH free-radical scavenging effect, showing that this polysaccharide has a moderate effect in inhibiting the formation of those radicals.
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Chitosan has been exploited as a material for the development of edible films, and additionally can be used as a carrier of functional compounds such as α-tocopherol. The aim of this work was to ...evaluate the effects of the incorporation of α-tocopherol in chitosan-based films. FTIR and thermal analyses were performed and showed that the incorporation of α-tocopherol affects the chemical structure of chitosan-based films with the establishment of new chemical bonds and the decrease of crystallinity. Results also showed that the increase of α-tocopherol concentration promotes a decrease of water content (from 12.6 to 11.4%) of the films. The addition of α-tocopherol to chitosan films leads to a significant reduction (
p
<
0.05) of tensile strength from 34.06 to 16.24
MPa, and elongation-at-break from 53.84 to 23.12%. Film opacity values (ranging from 4.74 to 7.83%) increased when α-tocopherol was incorporated into the film. Antioxidant capacity of chitosan-based films was evaluated and was enhanced when α-tocopherol was present in the film matrix. Results showed that α-tocopherol can be successfully added to the chitosan films enhancing the final quality and shelf-life extension of food products.
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► The effects of α-tocopherol in chitosan film properties were evaluated. ► The interactions between α-tocopherol and chitosan were confirmed by FTIR technique. ► Results showed that α-tocopherol can enhance antioxidant activity of chitosan films. ► Water vapor permeability of films increased as the α-tocopherol content increased. ► Chitosan-based films with α-tocopherol offered good UV barrier properties.
Hybrid gels can be used for controlled delivery of bioactives and for textural and rheological modification of foods. In this regard the hydrogel:oleogel ratio and gel development methodologies ...showed to be the aspects that influence most of their properties. The present study shows how different fractions of oleogel can influence the hydrogel matrix of an oleogel-in-hydrogel emulsified system in terms of polymorphic arrangement, microstructure, texture and rheology. The hydrogel was prepared by using an aqueous sodium alginate solution and the oleogel was prepared through the gelation of medium chain triglycerides with beeswax. Hybrid gels were prepared under constant shearing. Crystallinity was clearly changed as hydrogel and oleogel were combined. No polymorphism was observed in the X-Ray diffraction of hybrid gels, as these showed homogeneous results for all component ratios. The behaviour of samples with increasing oleogel-to-hydrogel ratio presented a decrease of both firmness and spreadability, and then, a decrease of gel adhesivity and cohesiveness. This textural response was a consequence of the disaggregated structure, stemming from the disruption of the hydrogel network, due to the inclusion of increasing amounts of oleogel. Rheological results showed that all hybrid gels presented a gel-like behaviour (G´ > G´´). Oleogel's strength influenced the overall textural and rheological performance of hybrid gels. This work demonstrates the possibility of producing hybrid gels aiming to tailor texture on food systems.
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This study uses the process simulator ASPEN Plus
® and Life Cycle Assessment (LCA) to compare three process design alternatives for biodiesel production from waste vegetable oils that are: the ...conventional alkali-catalyzed process including a free fatty acids (FFAs) pre-treatment, the acid-catalyzed process, and the supercritical methanol process using propane as co-solvent. Results show that the supercritical methanol process using propane as co-solvent is the most environmentally favorable alternative. Its smaller steam consumption in comparison with the other process design alternatives leads to a lower contribution to the potential environmental impacts (PEI’s). The acid-catalyzed process generally shows the highest PEI’s, in particular due to the high energy requirements associated with methanol recovery operations.
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