Active carboxymethyl cellulose-based edible coatings for the extension of fresh goldenberries shelf-life

Edible coatings based on natural sources are a good alternative to protect and increase the shelf-life of the fruits. In this work, active carboxymethyl cellulose (CMC)-based edible coatings enriched with functional ingredients, extracted from spent coffee grounds (SCG), were produced and used to increase the shelf-life of fresh goldenberries. Thus, three different treatments were tested on fresh goldenberries: (i) coating CMC (CMC-based edible coating); (ii) coating CMC-A (CMC-based edible coating with 0.2% (w/v) of polysaccharide-rich extract from SCG); and (iii) coating CMC-B (CMC-based edible coating with 0.2% (w/v) of polysaccharide-rich extract, and 0.2% (w/v) of phenolic compounds encapsulated from SCG), being compared with uncoated goldenberries. Physicochemical and microbiological properties of the fruits were evaluated throughout 12 and 28 days of storing at 20 °C and 65% relative humidity and 4 °C and 95% RH, respectively. The results showed that the temperature and relative humidity significantly influenced the quality of goldenberries, increasing their shelf-life almost two-fold when stored at 4 °C and 95% RH. Both CMC-A and CMC-B coatings controlled weight loss and decreased the gas transfer rates (O2, CO2, and C2H4), mainly when goldenberries were stored at 20 °C and 65% RH. Moreover, coating CMC-A was better for delaying microbial growth, while the edible coating CMC-B gave an extra content of phenolic compounds to goldenberries, increasing thus their antioxidant potential.This research was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit.info:eu-repo/semantics/publishedVersio

Extraction of antioxidant phenolic compounds from spent coffee grounds

The extraction of antioxidant phenolic compounds from spent coffee grounds (SCG) was studied. Extraction experiments were carried out by the conventional solid–liquid method, using methanol as solvent at different concentrations (20–100%), solvent/solid ratios (10–40 ml/g SCG), and extraction times (30–90 min), and the influence of these operational variables on the content of total phenolic compounds and antioxidant activity of the produced extracts was evaluated. Flavonoids, chlorogenic acid, and protocatechuic acid were found in all the produced extracts and were also quantified. A strong influence (p < 0.05) of the variables on the extraction results was verified, and the conditions able to maximize each response (contents of total phenolic compounds, flavonoids, chlorogenic acid and protocatechuic acid, and antioxidant activity) were established. Extraction using 60% methanol in a solvent/solid ratio of 40 ml/g SCG, during 90 min, was the most suitable condition to produce a extract with high content of phenolic compounds (16 mg gallic acid equivalents/g SCG) and high antioxidant activity (FRAP of 0.10 mM Fe(II)/g), simultaneously. These findings are of interest since antioxidant phenolic compounds have an outstanding role in health area, and wide applications in food and pharmaceutical products.This work was supported by the Portuguese Foundation for Science and Technology (FCT)

Production of a distilled spirit using cassava flour as raw material: chemical characterization and sensory profile

Cassava plays a key role in the food production and economies of several countries worldwide. Due to its starch content, alcoholic fermentation is a promising transformation process for adding value to cassava. However, most of the existing cassava beverages are from traditional origin, with the yields and quality often poorly known or controlled due to the use of artisanal production processes. This work aims at the application of easily implementable biotechnological tools for the production of cassava spirits, in order to add value to this raw material. Cassava flour was liquefied and saccharified using enzymatic cocktails, generating a fermentable broth with ~184 g L−1 of fermentable sugars. This was then fermented into an alcoholic product with ~10% ethanol by volume and distilled for spirit production. Cassava spirits with 40% ethanol by volume, with or without application of oak wood, were produced. For further valorization, volatile fractions of cassava spirits were characterized by gas chromatography–flame ionization detection (GC-FID) and GC–MS. These showed a predominance of yeast fermentation metabolites, complemented by wood extractives where oak chips were applied. Both produced spirits showed desirable sensory traits, receiving good acceptance by experienced tasters, demonstrating the feasibility of the proposed process to add value to cassava surplus.This study was supported by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit and BioTecNorte operation (NORTE-01-0145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 -Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio

Optimization of autohydrolysis conditions to extract antioxidant phenolic compounds from spent coffee grounds

Autohydrolysis, which is an eco-friendly technology that employs only water as extraction solvent, was used to extract antioxidant phenolic compounds from spent coffee grounds (SCG). Experimental assays were carried out using different temperatures (160 to 200 °C), liquid/solid ratios (5 to 15 ml/g SCG) and extraction times (10 to 50 min) in order to determine the conditions that maximize the extraction results. The optimum conditions to produce extracts with high content of phenolic compounds (40.36 mg GAE/g SCG) and high antioxidant activity (FRAP = 69.50 mg Fe(II)/g SCG, DPPH = 28.15 mg TE/g SCG, ABTS = 31.46 mg TE/g SCG, and TAA = 66.21 mg -TOC/g SCG) consisted in using 15 ml water/g SCG, at 200 °C during 50 min. Apart from being a green technology, autohydrolysis under optimized conditions was demonstrated to be an efficient method to extract antioxidant phenolic compounds from SCG.This work was supported by the Science and Technology Foundation of Portugal (FCT - grant SFRH/BD/80948/2011); the Strategic Project PEst-OE/EQB/LA0023/2013; and the Project “Bio-Ind -Biotechnology and Bioengineering for improved Industrial and Agro-Food processes”, REF. NORTE-07-0124-FEDER-000028 cofunded by the Programa Operacional Regional do Norte (ON.2 e O Novo Norte), QREN, FEDER

Laccase-mediator system for the ionic liquid-assisted treatment of a technical lignin with partial dissolution

The valorisation of lignin is a key aspect in the optimal exploitation of the paradigm of a biorefinery based on lignocellulosic biomass. In this work, the treatment of the technical lignin Indulin AT with a recombinant laccase, or with a combination of this enzyme with the mediator 2,2-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS), has been carried out at 25 °C in a mildly acidic buffered aqueous medium. The presence of the ionic liquid 1-ethyl-3-methylimidazolium acetate ([C2mim][OAc]) has also been investigated. Due to the limited solubility of Indulin AT in water, only partial dissolution occurred. In the lignin recovered after the treatments, a preferential diminution of the guaiacyl units was observed. In the analysis of the aqueous phases, a variety of phenolic compounds were identified, deriving from either guaiacyl or p-hydroxyphenyl units, although in moderately low concentrations. The highest assigned concentrations, always achieved when using the laccase-ABTS system (versus the treatment with no mediator), corresponded to different phenolic compounds, depending on whether the ionic liquid was involved or not in the treatment. In general, the overall concentration of phenolic compounds (measured as equivalents of gallic acid) was much greater after treatments involving the ionic liquid.This work was supported by Xunta de Galicia through grant numbers ED431B 2017/023 and ED431E 2018/01 (CRETUS Strategic Partnership), and by the Portuguese Foundation for Science and Technology (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit and by LABBELS – Associate Laboratory in Biotechnology, Bioengineering and Microelectromechanical Systems, LA/P/0029/2020. C.A.P. and H.R. are grateful to “Agrupación Europea de Cooperación Territorial – Galicia - Norte de Portugal (GNP-AECT)” for support of stays at the Centre of Biological Engineering of the University of Minho via the Iacobus programme. The use of RIAIDT-USC analytical facilities is also acknowledged.info:eu-repo/semantics/publishedVersio

Maximization of fructooligosaccharides and β-fructofuranosidase production by Aspergillus japonicus under solid-state fermentation conditions

The conditions of temperature, moisture content, and inoculum rate able to maximize the production of fructooligosaccharides (FOS) and β-fructofuranosidase (FFase) enzyme by solid-state fermentation were established. Fermentation assays were performed using the support material (coffee silverskin) moistened to 60, 70, or 80 % with a 240-g/l sucrose solution and inoculated with a spore suspension of Aspergillus japonicus to obtain 2 × 10 5, 2 × 10 6, or 2 × 10 7 spores/gram dry material. The fermentation runs were maintained under static conditions at 26, 30, or 34 °C during 20 h. The moisture content did not influence the FOS and FFase production; however, temperature between 26 and 30 °C and inoculum rate of approximately 2 × 10 7 spores/gram dry material maximized the results (FOS = 208.8 g/l with productivity of 10.44 g/l h; FFase = 64.12 units U/ml with productivity of 4.0 U/ml h). These results are considerably higher than those obtained under no optimized fermentation conditions and represent an important contribution for the establishment of a new industrial process for FOS and FFase production.This work was supported by grant SFRH/BPD/38212/2007 from the FCT (Portuguese Foundation for Science and Technology)

Active natural-based films for food packaging applications: the combined effect of chitosan and nanocellulose

This work aimed to evaluate the potential of chitosan/cellulose nanocrystals (CNC) films to be used as active pads for meat packages to prolong its shelf-life and preserve its properties over time. Several CNC concentrations (5, 10, 25, and 50wt%) were tested and the films were produced by solvent casting. The developed samples were characterized by ATR-FTIR, TGA, FESEM, and XRD. The transparency, antimicrobial, barrier and mechanical properties were also assessed. Finally, the films' ability to prolong food shelf-life was studied in real conditions using chicken meat. CNC incorporation improved the thermal stability and the oxygen barrier while the water vapor permeability was maintained. An enhancement of mechanical properties was also observed by the increase in tensile strength and Young's modulus in chitosan/CNC films. These films demonstrated bactericidal effect against Gram-positive and Gram-negative bacteria and fungicidal activity against Candida albicans. Lastly, chitosan-based films decreased the growth of Pseudomonas and Enterobacteriaceae bacteria in meat during the first days of storage compared to commercial membranes, while chitosan/CNC films reduced the total volatile basic nitrogen (TVB-N), indicating their efficiency in retarding meat's spoilage under refrigeration conditions. This work highlights the great potential of natural-based films to act as green alternatives for food preservation.The authors are thankful to project UID/CTM/00264/2019 of 2C2T - Centro de Ciencia e Tecnologia Textil, funded by National Founds through FCT/MCTES-Fundacao para a Ciencia e a Tecnologia. Sofia M. Costa is thankful to FCT PhD Scholarship (SFRH/BD/147517/2019). Diana Ferreira is thankful to CEECIND/02803/2017. The authors are also thankful for the financial support of the Portuguese Fundacao para a Ciencia e a Tecnologia (FCT) under the scope of the strategic funding of UIDB/04469/2020 unit and BioTecNorte operation (NORTE-010145-FEDER-000004) funded by the European Regional Development Fund under the scope of Norte2020 -Programa Operacional Regional do Norte.info:eu-repo/semantics/publishedVersio