Browsing by Author "Atatoprak, Tugba"
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- Extraction and characterisation of cellulose nanocrystals from pineapple peelPublication . Madureira, Ana Raquel; Atatoprak, Tugba; Çabuk, Duygu; Sousa, Flávia; Pullar, Robert C.; Pintado, ManuelaThe potential of pineapple peel as a source of cellulose nanocrystals was evaluated. Peels skin from fresh-cut fruit was used as raw material. These residues were puri ed to remove pigments, lipids and hemicellulose, and a bleaching process for deligni cation was carried out for 4-6 h. All resulting products were characterised for their lignin, hemicellulose, cellulose and ash contents using standard techniques. Dry matter at the end was low (ca. 50%) compared with the raw material (ca. 90%). The process applied resulted in ca. 20% (m/m) of puri ed cellulose (ca. 80% purity), with ineligible levels of lignin and hemicellulose present, especially when using 6h of bleaching. The puri ed cellulose was subject to acid hydrolysis for nanocrystal extraction with two testing times, 30 and 60 minutes. These cellulose nanocrystals had small sizes (< 1000 nm), with high variability and negative zeta potential values. The time of extraction did not a ect the nanocrystals' chemical and physical properties. The use of 6 h of bleaching treatment during puri cation was shown to be more e ective than 4 h. Pineapple peel was demonstrated to be a good source of cellulose for the production of cellulose nanocrystals.
- Potentialities of the extraction technologies and use of bioactive compounds from winery by-products: a review from a circular bioeconomy perspectivePublication . Machado, Adriana Rodrigues; Atatoprak, Tugba; Santos, Joana; Alexandre, Elisabete M. C.; Pintado, Manuela Estevez; Paiva, Jorge A.P.; Nunes, JoãoAgro-industrial by-products and by-products from the wine industry (pomace, peels, leaves, stems, and seeds) represent a potential economic interest because they are usually relevant natural sources of bioactive compounds, which may present significant biological activities related to human health and well-being. This article aims to review wine and winery industry by-products as potential natural sources of antioxidant, antimicrobial, anti-inflammatory, antiaging, and anticancer compounds, as well as briefly highlighting the extraction methods used to obtain these bioactive compounds and explore their potential applications in the food, cosmetic, and packaging industries. Although there are some studies of wine industry by-products with different origins, this revision will be mainly focused on the Portuguese vineyard industry since it represents an import industrial sector as proof of the diversity of the bioactive compounds identified. Therefore, the recovery of these bioactive molecules that act as antioxidants and health-promoting agents may promote a variety of industries at the same time as the circular economy.