•Coffee silverskin presented a real protein content of 12%.•One quarter of the total nitrogen corresponded to the non-protein fraction.•An automated on-line amino acid derivatization protocol was ...adapted and validated.•Aspartic acid (10.2 mg/g) and glutamic acid (9.2 mg/g) were the major amino acids.•Branched chain amino acids were also present in substantial amounts.
Silverskin, the main coffee roasting by-product, is rich in fiber, protein and antioxidants. Its protein fraction was studied regarding total, protein and non-protein nitrogen content. Amino acids were analysed after automated on-line derivatization. The method showed to be precise (<6.9%) and accurate (recoveries using a certified reference material and spiked blanks: 90–102%; for spiked samples: 73–113%). The real protein content of silverskin was 12%. One quarter of the total nitrogen corresponded to the non-protein fraction. All essential amino acids were present in the free form, except methionine. Regarding total amino acids, aspartic and glutamic acids (9–10 mg/g) were the major compounds. Branched chain amino acids (leucine, isoleucine and valine) were also present in substantial amounts (5–8 mg/g), as well as proline and arginine (~5 mg/g). Concluding, silverskin is a source of amino acids with relevance for the improvement of cognitive and physical performances.
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•Olive by-products are a potential source of bioactive compounds.•Olive by-products are rich in oleuropein, fatty-acids and minerals.•These wastes could be a new source of ingredients ...for cosmetic field.•Effects of olive by-products on skin were evaluated.
Olive tree is a traditional plant which fruits (Olea europaea L.) are used for olive oil production, especially in Mediterranean countries. Olive oil extraction produces by-products, which can become a major environmental issue. Recently, some studies have been carried out on these residues regarding phytochemical identification and biological and toxicological evaluation. The bioactive compounds contained by these by-products have a high antioxidant activity (especially oleuropein), a characteristic fatty acids profile and an interesting mineral composition. Indeed, taking into account its composition and sustainability issues, the reuse of these disposal residues is advisable. These agro-industrial by-products have the potential to be used with different purposes, providing economical advantage. In particular, the field of skin care products and cosmetics may benefit from these remaining materials, as those bioactive compounds can fulfill a real cosmetic function and activity. This review presents the composition of the different olive by-products and their bioactive compounds. The possible application of these wastes as cosmetic ingredients was critically reviewed.
Over the years, food industry wastes have been the focus of a growing interest due to their content in high added-value compounds. A good example are the olive oil by-products (OOBP), which retain a ...great amount of phenolic compounds during olive oil production. Their structure and biological properties justify their potential use as antioxidants in other food products. The efficient recovery of phenolic compounds has been extensively studied and optimized in order to maximize their reintroduction in the food chain and contribute to a higher valorization and better management of wastes from olive oil industry.
This paper reviews the most representative phenolic compounds described in OOBP and their biological properties. New extraction procedures to efficiently recover these compounds and the most advanced chromatographic techniques that have been used for a better understanding of the phenolic profile of these complex matrices are also referred. Finally, this paper reports the main applications of OOBP, with emphasis on their phenolic content as natural antioxidants for food applications.
Besides their antioxidant activity, phenolic compounds from OOBP have also shown antimicrobial and antitumoral properties. Their application as food antioxidants requires new extraction techniques, including the use of non-toxic solvents and, in a pilot scale, the use of filters and adsorbent resins. The inclusion of phenolic compounds from OOBP in some food matrices have improved not only their antioxidant capacity but also their sensory attributes.
•An overview of bioactive phenolic compounds in olive wastes is presented.•New techniques for phenolic extraction using safer solvents are highlighted.•Methods used for phenolics identification and quantification are reviewed.•The potential application of these compounds as food antioxidants is discussed.
Algae are a complex, polyphyletic group of organisms, affordable and naturally rich in nutrients, but also valuable sources of structurally diverse bioactive substances such as natural pigments. The ...aim of this work was to evaluate the polar and non-polar pigment contents of different commercial dried algae (brown: Himanthalia elongata, Undaria pinnatifida, Laminaria ochroleuca; red: Porphyra spp.; and a blue-green microalga: Spirulina spp.). The pigment extraction was carried out using different solvents (100% methanol, 100% methanol acid free, 100% ethanol, 90% acetone, N,N-dimethylformamide, dimethyl sulfoxide-water (4:1, v/v) and pH 6.8 phosphate buffer), selected according to their affinity for each class of pigments. Acetone proved to be an efficient solvent to extract chlorophylls from brown and red algae, but not from Spirulina spp. Porphyra spp. presented considerably higher levels of all pigments compared to brown algae, although Spirulina spp. presented significantly higher (p < 0.05) levels of chlorophylls, carotenoids and phycobiliproteins, compared to all macroalgae. The content of fucoxanthin extracted from the three brown algae was highly correlated to the carotenoid content. Within this group, Himanthalia elongata presented the highest fucoxanthin/total carotenoids ratio. Although the yield of extraction depended on the solvent used, the algae studied herein are an interesting source of pigments of great value for a wide range of applications.
This comprehensive review points out the major developments on the recovery of bioactive compounds of olive by-products, intending innovative food applications and enhanced technological functions. ...Nutritional and sensorial factors influencing consumers' acceptance are also discussed. Besides being an economic burden for producers, olive oil by-products also represent a severe environmental problem. Simultaneously, these are rich in bioactive compounds, which are remarkable added-value ingredients for other industries. New applications have been focused in ameliorating the food nutritional profile, replacing or improving technological properties/functions of food additives, and extending food products shelf life. Eco-friendly food packaging is also a promissory application field. The improvement of nutritional functionality and sensory quality of enriched food is another challenging task. Despite the large chemical characterization of olive products and olive oil processing by-products, further research is still needed to fully understand the potential of this valuable raw material.
High added-value ingredients can be obtained by recovering bioactive compounds from olive by-products. Those can be used by food industry to improve food product nutritional profile and/or with a technological functionality. This review presents food applications developed with ingredients and bioactive compounds derived from olive processing by-products. It aims to be useful for food industries and other agro-industrial stakeholders in order to encourage and expand the utilization of olive by-products in the development of innovative food products.
•There has been a great by-products generation with the growth of olive oil production.•Olive by-products have high content in bioactive compounds.•Olive by-products have high potential to be used in food applications.•Food functional properties are improved using olive by-products as ingredients.•Food technological properties are improved using olive by-products as ingredients.
Seaweeds are a recognized source of bioactive compounds and techno-functional ingredients. However, its protein fraction is still underexplored. The aim of this study was to determine the total and ...free amino acid profile and protein content of four seaweeds species (Porphyra dioica, Porphyra umbilicalis, Gracilaria vermiculophylla, and Ulva rigida) produced in an integrated multi-trophic aquaculture system, while assessing their protein quality. Samples were submitted to acid and alkaline hydrolysis (total amino acids) and to an aqueous extraction (free amino acids) followed by an automated online derivatization procedure, and analyzed by reverse phase-high performance liquid chromatography. Protein-, non-protein and total-nitrogen were quantified by the Kjeldahl method. Crude and true protein contents were estimated based on the nitrogen and amino acid composition. Protein quality was assessed based on the amino acids profile. Porphyra species presented the highest protein content compared to the remaining three seaweed species tested. All samples presented a complete profile of essential amino acids and a high quality protein profile, according to World Health Organization and Food and Agriculture Organization standards. Methionine and tryptophan were the first limiting amino acids in all species. Red species (Porphyra and Gracilaria) presented high levels of free alanine, glutamic, and aspartic acids. The results highlight the potential of using seaweeds as an alternative and sustainable source of protein and amino acids for human nutrition and industrial food processing.
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•Blades and protein isolates of P. dioica were digested.•Simulated gastrointestinal digestion produced small bioactive peptides.•Digested blades presented higher ORAC values compared ...to protein isolates.•Protein isolates presented higher FRAP and ABTS+• inhibition values.•Simulated gastrointestinal digestion improved the antioxidant activity of samples.
Porphyra sp. is one of the most cultivated and commercially valuable species, recognized for its high protein content (up to 47% dry weight) and complete amino acids profile. Based on these characteristics, P. dioica produced in an integrated multitrophic aquaculture system was selected for this study. The aim was to evaluate the effect of in vitro simulated gastrointestinal digestion (SGID) on the antioxidant activity of the hydrolysates generated from dried blades and from the protein isolate (PI) extracted from them. The alkali extraction and isoelectric precipitation (pH 4.5) of P. dioica protein prior SGID allowed isolating/enriching protein, while direct SGID of blades allowed assessing the potential influence of other constituents of the sample on the bioactive properties. Overall, SGID promoted the release of smaller bioactive peptides and their in vitro antioxidant activity, which was assessed by different methods (DPPH and ABTS+ scavenging capacity, ORAC and FRAP), was improved compared to the intact samples. Blades submitted to direct SGID presented significantly higher ORAC values compared to PI (2010 ± 136 vs 542 ± 21 µmol TE/g FDS, respectively). For the remaining assays, PI presented more potent antioxidant activity, especially FRAP (131 ± 2 vs 16 ± 1 µmol TE/g FDS) and ABTS+ (1244 ± 157 vs 230 ± 15 µmol TE/g FDS). The results indicated that gastrointestinal digestion improved the antioxidant activity of P. dioica-derived hydrolysates, as they presented effective activity against different oxidative mechanisms, thus suggesting health-protecting effects.
Enzymatic hydrolysis has been employed to modify protein functional properties and discover new sources of antioxidants. In this study, the effect of different enzymatic treatments on antioxidant ...activity of
(blades and protein isolate (PI)) was investigated. Protein nitrogen content of
blades and PI were 23 and 50% (dry weight), respectively. Blades and PI were hydrolyzed with Prolyve® and Prolyve® plus Flavourzyme®. Peptide profiles and molecular mass distribution of the hydrolysates were investigated. The hydrolysis promoted generation of peptides and low molecular mass components <1 kDa. Antioxidant activity was assessed using ferric reducing antioxidant power (FRAP), 2,2-diphenyl-1-picrylhydrazyl (DPPH·) scavenging, 2,2'-azinobis-(3-ethylbenzothiazoline-6-sulfonate) (ABTS·+) inhibition, and reactive oxygen species scavenging ability, i.e., oxygen radical absorbance capacity (ORAC) and hypochlorous acid (HOCl) scavenging assays. In general, enzymatic hydrolysis of
blades and PI enhanced the in vitro antioxidant activity. Direct hydrolysis of blades improved ORAC values up to 5-fold (from 610 to 3054 μmol Trolox eq./g freeze dried sample (FDS). The simultaneous release of phenolic compounds suggested a potential synergistic activity (ORAC and ABTS·+ assays). Such hydrolysates may be of value as functional food ingredients.
Macroalgae are a natural source of valuable compounds for different applications. Despite the high protein content (up to 47%) and complete essential amino acid profile in some species, their protein ...fraction is still relatively underexplored. Besides the potential as alternative protein sources, macroalgae can also provide bioactive peptides and other proteinaceous compounds with biological value.
In this review, data associated with macroalgal nitrogenous components, particularly peptides and protein hydrolysates, are presented and discussed, especially regarding their potential health properties and methodologies employed to obtain and isolate them.
Obtaining these compounds and assessing their biological activities involves a combination of preparation and analytical steps (e.g. isolation, purification, detection and quantification). Hydrolysis of macroalgal proteins using different proteinases generates multiple peptides with a broad range of biological activities. Further research and innovation will allow the development of more efficient production processes and will improve the range of applications. Current scientific evidences regarding the potential health benefits of macroalgae-derived proteinaceous compounds highlight the need of additional investments to effectively transfer promising findings into market driven opportunities.
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•Macroalgae contain proteinaceous compounds with numerous biological functions.•Enzymatic protein hydrolysis generates new peptides with different biological actions.•Methodologies to obtain and isolate macroalgae-derived peptides are presented.•Studies are needed to transfer scientific knowledge into commercial opportunities.
A gold nanoparticle-coated screen-printed carbon electrode was used as the transducer in the development of an electrochemical immunosensor for Ara h 1 (a major peanut allergen) detection in food ...samples. Gold nanoparticles (average diameter=32nm) were electrochemically generated on the surface of screen-printed carbon electrodes. Two monoclonal antibodies were used in a sandwich-type immunoassay and the antibody–antigen interaction was electrochemically detected through stripping analysis of enzymatically (using alkaline phosphatase) deposited silver. The total time of the optimized immunoassay was 3h 50min. The developed immunosensor allowed the quantification of Ara h 1 between 12.6 and 2000ng/ml, with a limit of detection of 3.8ng/ml, and provided precise (RSD <8.7%) and accurate (recovery >96.6%) results. The immunosensor was successfully applied to the analysis of complex food matrices (cookies and chocolate), being able to detect Ara h 1 in samples containing 0.1% of peanut.
•A gold nanostructured electrochemical immunosensor for Ara h 1 detection in food was developed.•Ab–Ag interaction was detected through stripping analysis of enzymatically deposited silver.•The limit of detection of the immunosensor was very low (3.8ng/ml).•The immunosensor was able to detect Ara h 1 in samples containing 0.1% of peanut.
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