دانلود رایگان مقاله لاتین استخراج پلی ساکارید توسط هیدرولیز از سایت الزویر
عنوان فارسی مقاله:
استخراج پلی ساکاریدها توسط هیدرولیز خودکار زمین قهوه و ارزیابی فعالیت آنتی اکسیدانی خود
عنوان انگلیسی مقاله:
Extraction of polysaccharides by autohydrolysis of spent coffee grounds and evaluation of their antioxidant activity
سال انتشار : 2016
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مقدمه انگلیسی مقاله:
1. Introduction
Coffee, being one of the most popular and appreciated beverages around the world, is considered an important source of polysaccharides, mainly galactomannans, arabinogalactans, and cellulose (Arya & Rao, 2007; Ballesteros, Teixeira, & Mussatto, 2014a; Mussatto, Machado, Martins, & Teixeira, 2011; Nunes, Domingues, & Coimbra, 2005). Coffee galactomannans are composed of a backbone of -(1→4)-linked mannose residues containing single galactose side groups with different degrees of branching (Nunes et al., 2005). They are high molecular weight polysaccharides and show a low level of branching. Nonetheless, the roasting process influences on the depolymerization and debranching of galactomannans, increasing thus, their extraction and solubility in water (Simões, Maricato, Nunes, Domingues, & Coimbra, 2014). On the other hand, coffee type II arabinogalactans are also high molecular weight polysaccharides, highly branched, composed of a backbone of -(1→3)-linked galactose residues and side chains of galactose and arabinose residues (Passos & Coimbra, 2013). Due to their structure, arabinogalactans are the coffee polysaccharides most expose to degradation during the roasting and the arabinose side chains are the first in to be hydrolyzed (Oosterveld, Harmsen, Voragen, &Schols, 2003). Both, galactomannans and arabinogalactans strongly affect the quality and properties of the final beverage. However, the majority of them (around 70% of total polysaccharides from roasted coffee) (Arya & Rao, 2007) remain in the residue generated after soluble coffee preparation, named as spent coffee grounds (SCG). Currently, there is an especial interest in the use of non-digestible polysaccharides obtained from natural sources, including coffee and its wastes. Some findings have shown the antimicrobial and antioxidant capacities of polysaccharides extracted from SCG (Ballesteros, Cerqueira, Teixeira, & Mussatto, 2015) and the immunostimulatory properties provided by coffee galactomannans (Simões et al., 2009) and arabinogalactans (Gotoda et al., 2007). The prebiotic potential of coffee residue mannans has been also proved since it improves the health of human intestinal microflora (Asano et al., 2001; Gniechwitz, Reichardt, Blaut, Steinhart, & Bunzel, 2007). The extraction of polysaccharides from SCG has been studied through different methods, mainly using chemicals as extraction agents. Sodium hydroxide (Ballesteros et al., 2015; Simões, Nunes, Maria do Rosário, & Coimbra, 2010; Simões et al., 2009) and potassium hydroxide (Fischer, Reimann, Trovato, & Redgwell, 2001), for example, have been employed in alkali treatments, while sulfuric acid has been used to recover carbohydrates by dilute acid hydrolysis of SCG (Mussatto, Carneiro, Silva, Roberto, & Teixeira, 2011). Autohydrolysis is an eco-friendly technology that does not require the use of chemical agents for reaction. This technique has been used to extract polysaccharides from different natural sources such as Eucalyptus globulus wood (Romaní, Garrote, López, & Parajó, 2011), Pinus pinaster wood and rice husks (Rivas, Conde, Moure, Domínguez, & Parajó, 2013), among others. During autohydrolysis, a slightly acid medium is obtained due to the partial release of acetyl groups from the material structure, providing a selective depolymerization of the hemicellulose (Nabarlatz, Ebringerová, & Montané, 2007). Autohydrolysis of lignocellulosic materials is a complex process since many factors such as the liquid/solid ratio, temperature, particle size of the solid matrix, the extraction time, as well as the structure and polymerization degree of molecules and their interaction with proteins, minerals, and phenolic compounds can influence in the reaction efficiency. Taking these facts into account, the purpose of the present study was to evaluate the extraction of polysaccharides from SCG by using the environmentally friendly technique of autohydrolysis. Assays were performed using different temperatures, liquid/solid ratios and extraction times, and the effects of these operational variables on the extraction yield and antioxidant activity ofthe recovered polysaccharides were verified. The polysaccharides obtained under the best autohydrolysis conditions were chemically and structurally characterized.
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کلمات کلیدی:
Extraction of polysaccharides by autohydrolysis of spent coffee ... https://repositorium.sdum.uminho.pt/bitstream/1822/42764/1/document_43169_1.pdf by LF Ballesteros - 2017 - Cited by 2 - Related articles Sep 15, 2016 - Extraction of polysaccharides by autohydrolysis of spent coffee grounds and evaluation of their antioxidant activity. Lina F. Ballesterosa, José A. Extraction of polysaccharides by autohydrolysis of spent coffee ... orbit.dtu.dk/.../extraction-of-polysaccharides-by-autohydrolysis-of-spent-coffee-grou... Autohydrolysis was demonstrated to be an efficient technique to recover ... Spent coffee grounds, Autohydrolysis, Polysaccharides, Antioxidant activity, Structural ... Extraction of polysaccharides by autohydrolysis of spent coffee ... isi-dl.com/item/125367 Extraction of polysaccharides by autohydrolysis of spent coffee grounds and evaluation of their antioxidant activity. sciencedirect.com ... 204-01 Extraction of Polysaccharides by Autohydrolysis of Spent ... www.ift.org/Meetings-and.../Technical%20Abstract%20Search%20Details.aspx?id... Abstract, Spent coffee grounds (SCG) are the major wastes obtained during the ... to extract polysaccharides from SCG by using the autohydrolysis technique. Lina Fernanda Ballesteros - Google Scholar Citations https://scholar.google.com/citations?user=ukfEfowAAAAJ&hl=en Extraction of antioxidant phenolic compounds from spent coffee grounds ... Extraction of polysaccharides by autohydrolysis of spent coffee grounds and ... OpenAIRE - Project: EXTRACTION AND CHARACTERIZATIO... https://www.openaire.eu/search/project?projectId=fct... Characterization of polysaccharides extracted from spent coffee grounds by alkali ... Extraction of polysaccharides by autohydrolysis of spent coffee grounds and ...
