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- Valorization of By-Products from Commercial Fish Species: Extraction and Chemical Properties of Skin GelatinsPublication . Sousa, Sérgio; Vázquez, José; Pérez-Martín, Ricardo; Carvalho, Ana; Gomes, AnaFish skins constitute an important fraction of the enormous amount of wastes produced by the fish processing industry, part of which may be valorized through the extraction of gelatins. This research exploited the extraction and characterization of gelatins from the skin of three seawater fish species, namely yellowfin tuna (Thunnus albacares), blue shark (Prionace glauca), and greenland halibut (Reinhardtius hippoglossoides). Characterization included chemical composition, rheology, structure, texture, and molecular weight, whereas extraction studies intended to reduce costly steps during extraction process (reagents concentration, water consumption, and time of processing), while maintaining extraction efficiency. Chemical and physical characterization of the obtained gelatins revealed that the species from which the gelatin was extracted, as well as the heat treatment used, were key parameters in order to obtain a final product with specific properties. Therefore, the extraction conditions selected during gelatin production will drive its utilization into markets with well-defined specifications, where the necessity of unique products is being claimed. Such achievements are of utmost importance to the food industry, by paving the way to the introduction in the market of gelatins with distinct rheological and textural properties, which enables them to enlarge their range of applications.
- Seaweeds from the Portuguese coast as a source of proteinaceous material: Total and free amino acid composition profilePublication . Vieira, Elsa Ferreira; Soares, Cristina; Machado, Susana; Correia, Manuela; Ramalhosa, Maria João; Oliva-Teles, MT; Carvalho, Ana; Domingues, Valentina; Antunes, Filipa; Oliveira, Teresa Azevedo Cardoso; Morais, Simone; Delerue-Matos, CristinaThe total protein content and the (total and free) amino acid composition of nine edible species of red, brown and green seaweeds collected in the Portuguese North-Central coast were quantified to assess their potential contribution to the recommended dietary intake. Whenever possible, the protein and amino acid composition was compared with that of commercial European seaweeds. The protein content was the highest (P < 0.05) in red species (19.1-28.2 g/100 g dw), followed by the green seaweed Ulva spp. (20.5-23.3 g/100 g dw), with the lowest content found in brown seaweeds (6.90-19.5 g/100 g dw). Brown seaweeds presented the lowest mean contents of essential amino acids (EAAs) (41.0% protein) but significantly (P < 0.05) higher concentrations of non-essential amino acids (36.1% protein) and free amino acids (6.47-24.0% protein). Tryptophan, methionine and leucine were the limiting EAAs in all species. In contrast, lysine was found in high concentrations, especially in red (2.71-3.85% protein) and green (2.84-4.24% protein) seaweeds.
- Use of coffee by-products for the cultivation of Pleurotus citrinopileatus and Pleurotus salmoneo-stramineus and its impact on biological properties of extracts thereofPublication . Freitas, Ana C.; Antunes, Mariana B.; Rodrigues, Dina; Sousa, Sérgio; Amorim, Manuela; Barroso, Maria de Fátima; Carvalho, Ana; Ferrador, Sandra M.; Gomes, Ana M.Incorporating spent coffee grounds (SCGs), a by-product from coffee brewing, in growth substrate of ben-eficial edible mushrooms is an approach that has to be further studied due to its potential positive out-comes: environmental impact mitigation, production costs reduction and beneficial impact on consumerhealth. Hence, cultivation ofPleurotus citrinopileatusandPleurotus salmoneo-stramineuswas tested usingSCG which enabled maximum production yield ofP. citrinopileatuswhich was of 25.1% (w/w). Variableantidiabetic potential was observed between aqueous and enzymatic extracts (3.8%–29% inhibition)regardless species and substrates, whereas aqueous extract ofP. citrinopileatusgrown in substrate withoutSCG stood out presenting the highest antioxidant activity and inhibition activity of angiotensin I-convert-ing enzyme (IC50=123lgmL 1). Ethanolic and aqueous extracts of bothPleurotusspecies grown in thepresence or absence of SGC proved to be an interesting prebiotic source for growth ofBifidobacteriumanimalisBo in comparison with fructooligosaccharides (FOS)
- Bioactive compounds of sweet and sour cherry stems obtained by subcritical water extractionPublication . Švarc-Gajić, Jaroslava; Cerdà, Víctor; Clavijo, Sabrina; Suárez, Ruth; Mašković, Pavle; Cvetanović, Aleksandra; Delerue-Matos, Cristina; Carvalho, Ana; Novakov, VesnaBACKGROUND Sweet cherries (Prunus avium L.) and sour cherries (Prunus cerasus L.) contain substantial amounts of anthocyanins and polyphenolics, and their stems have been used in traditional medicine for centuries. However, comparative data on the composition of sweet and sour cherry stems using the same analytical methodologies are limited. Moreover, there is no data in terms of biological activity of subcritical water extracts of cherry stems. RESULTS AND DISSCUSION Results obtained by using several assays that focused on different mechanisms showed that subcritical water extracts of sour and sweet cherry stems were powerful antiradicals and antioxidants. Anti‐proliferative properties measured by MTT (3‐[4,5‐ dimethylthiazol‐2‐yl]‐2,5 diphenyl tetrazolium bromide) test showed prominent cytotoxicity against different tumor cell lines. Inhibitory concentrations obtained were in the range 8.38–11.40 µg mL‐1. GC–MS (gas chromatography mass spectrometry) analysis showed the presence of alcohols, fatty acids, organic acids and other organic compounds. However, the chemical compositions of the two samples observed were similar, indicating similar chemical composition of sour and sweet cherry stems. CONCLUSION Subcritical water extracts of cherry stem demonstrated excellent biological activity and the potential to be used for pharmaceuticals or supplements due to confirmed high antioxidant, antiradical and antitumor activity.