Chemical characterization and antio

Chemical characterization and antioxidant properties of a new coffee blend with cocoa, coffee silverskin and green coffee minimally processed

The search for new technologies and ingredients with interesting characteristics and potential for incorporation into functional foods emerges in parallel with the demand for alternative sustainable and economically viable blends. Pursuing these aims, the formulation of a new coffee blend with 94% roasted coffee powder (Coffea canephora cv. Robusta andCoffea arabica,70/30,w/w), 3% cocoa powder, 2% coffee silverskin and 1% golden coffee (green coffee minimally processed) was developed. The influence of the ingredients in the blend was compared with two other commercial coffee blends (in capsule and in a sealed package with a one-way degassing valve), being characterized the formulation, the physicochemical parameters, as its innovation. It is concluded that the developed coffee blend shows an enriched content of bioactive compounds (chlorogenic acids, trigonelline,theobromine and caffeine), displays an important antioxidant capacity and was favorably appreciated due to its sensory characteristics. Moreover, the addition of skin by-product becomes an additional valorization and the processing of green coffee and cocoa was minimized by adding innovation and an optimized extraction

1. Introduction
Coffee is a tropical crop that from cultivation to thefinal product for consumption, involvesca. 500 million people in its management. In this context, although the genusCoffeacomprises more than 100
species,Coffea arabicaL. andCoffea canephoraPierre ex A. Froehner have special economic relevance, as they are responsible forca. 99% of the world coffee bean production (DaMatta & Ramalho, 2006;
Partelli et al., 2011) worldwide consumed. Coffee production generates over US$ 90,000 million each year and grows in ca. 80 countries, making it one of the world's most traded agricultural products and the economic basis of many tropical developing countries (Ramalho et al.,2013). In this context, the green coffee bean is minimally processed originating the golden coffee and accounting for approximately 95% of coffee exports. A large share of the profits in the coffee supply chain goes to the middlemen and the large roasting companies. This trade is controlled byfive large companies: Neumann and Volcafé (both based in Germany), Cargill, Decotrade (trading arm of Sara Lee/Douwe Egberts) and Taloca (owned by Philip Morris/Kraft), both based in Switzerland. Coffee roasters process green coffee beans into a variety of end-products, includingfilter coffee, instant coffee, and the new ‘coffee pads’. Almost 45% of the green coffee imports are purchased by thefive largest roasters, which mainly sell their processed coffees in the European, American and Japanese markets. Nestlé and Philip Morris/Kraft each process 13%, while Tchibo purchases 4% for the German market. Proctor & Gamble sells most of its share (4%) in the United States. Sara Lee/Douwe Egberts roasts 10%, which is sold mainly in the European and Brazilian markets. Nestlé dominates the soluble coffee market with a market share of over 50% (FairTrade Foundation,2012; TCC, 2014). Recent studies have shown that consumption of coffee and its byproducts, besides being a rich source of antioxidants for human ingestion (Esquivel & Jiménez, 2012; Murthy & Madhava-Naidu, 2012), also has other beneficial bioactive compounds (namely, caffeine, trigonelline and chlorogenic acids) for human health, being a potential functional
food product (Bonita, Mandarano, Shuta, & Vinson, 2007; Dórea & da Costa, 2005; Esquivel & Jiménez, 2012; Farah, Monteiro, Calado, Franca, & Trugo, 2006; Murthy & Madhava-Naidu, 2012). Caffeine is a
methylxanthine which is known to have positive health effects, namely by lowering cancer, diabetesmellitus, Alzheimer's, Parkinson's disease and cardiovascular risks, as well as the cognitive decline associated with aging, whereas the levels of neurotransmitters such as norepinephrine, acetylcholine, dopamine, serotonin and glutamate increase (Arendash & Cao, 2010; Cao et al., 2012; Hasan, Gattellari, & Cordato, 2010; Nkondjock, 2009; Smith, 2002; Thompson & Keene, 2004;
Zhang, Lee, Cowan, Fabsitz, & Howard, 2011). Caffeine also has antiinflammatory properties, mostly due to the similarity in the molecular structure to the nucleotide adenosine (Bicho, Leitão, Ramalho, & Lidon,
2011a). In this context, as methylxanthines have a heterocyclic ring with nitrogen included in the ring structure, being derived from amino acids, the action of adenosine is blocked by acting as a competitive inhibitor for the A1 and A2a adenosine receptor (Snyder, 1981). Trigonelline, an alkaloid formed by the methylation of the nitrogen atom of niacin, has hypoglycemic, hypolipidemic, neuroprotective,
antimigraine, sedative, memory-improving, antibacterial, antiviral, and anti-tumor activities, and it also has been shown to reduce diabetic auditory neuropathy and platelet aggregation (Zhou, Chan, & Zhou,
2012). It acts by affectingβcell regeneration, insulin secretion, activities of enzymes related to glucose metabolism, reactive oxygen species, axonal extension and neuron excitability (Zhou et al., 2012).
Chlorogenic acid, the ester of caffeic acid and quinic acid, is a natural antioxidant that has antihypertensive effects, prevents diabetes, improves glucose control in normal, pre-diabetic and diabetic people and further is a chemical sensitizer responsible for human respiratory allergy to certain types of plant materials (Freedman, Shulman, Krupey, & Sehon, 1964; Zhao, Wang, Ballevre, Luo, &
Zhang, 2011). The development of food products with high-fiber products (good [insoluble dieteticfiber/soluble dieteticfiber] ratio) and compounds with antioxidant activities (Martínez et al., 2012) further is an advantage for the human diet. In this context, the inclusion of silverskin and
cocoa powder in the coffee blends can provide additional functional characteristics to the beverage. Indeed, coffee silverskin, which is a tegument of coffee beans obtained as a by-product of the roasting process, has a high concentration of soluble dietaryfiber (86% of total dietary fiber) and high antioxidant capacity, probably due to the concentration of phenolic compounds in coffee beans, as well as to the presence of other compounds formed by the Maillard reaction during the roasting process, such as melanoidins (Mussatto, Machado, Martins, & Teixeira, 2011). Indeed, the Maillard reaction implicates an initial synthesis of N glycoside, then immonium ions that through isomerization originates ketosamine then either dehydrates into reductones and dehydro reductones, which are caramel, or short chain hydrolyticfission products such as diacetyl, acetol or pyruvaldehyde which then undergo the
Strecker degradation. Moreover, after cocoa beans are pealed, cleaned and roasted, they are shelled and then passed through huskers to separate the shells, husks and germs from the nibs. The nibs are roasted and ground to produce a cocoa liquor mass that, after solidification, turns into liquor blocks. By hydraulic pressing of the liquor blocks, most of the liquor's fat content can be freed in the form of cocoa butter. The remaining press cake, which still contains some fat, after pulverization originates the cocoa powder. Cocoa powder contains phenethylamine, which is a neurotransmitter that acts as a mood elevator and a natural antidepressant, and further seems to boost endorphins and serotonin, which also are neurotransmitters having antidepressant effects (Lippi et al., 2008). Cocoa also contains about 44 mg offlavonoids per gram, therefore being one of the highest polyphenol-containing foods (Shiina et al., 2009). It has also been argued that cocoa may lower LDL and cholesterol, reduce the risk of blood clots, increase bloodflow to the arteries, lower high blood pressure, boost cognitive performance and provide essential minerals such as calcium and potassium (Lippi et al., 2008; Shiina et al., 2009). Nevertheless, the formulation of a functional blend structured in a basic coffee beverage, depends on many factors, namely of species and origins, harvest and post-harvest operations and bean selection, storage
conditions and roasting differentiation (Läderach et al., 2011; Nair, 2010). This work aimed at to develop a new coffee blend and its beverage with functional potential, providing high antioxidant content and new flavors, to be used in the food industry. In this context, the influence of the degree of grinding and the use of different coffee machines in the chemical characterization and antioxidant capacity of the drinks were also assessed.