Total phenolic content and primary antioxidant capacity of aqueous extracts of coffee husk: chemical evaluation and beverage development

Abstract

This study aimed to evaluate the efficiency of aqueous extraction to obtain bioactive phytochemicals from grains and residual husk of organic Arabic coffee, as well as to develop a beverage with high antioxidant capacity and assess its sensorial acceptability. Aqueous extracts were obtained from dried and crushed coffee beans and husk. Various extraction methods were used to select the one capable of extracting the most amount of total phenolic constituents. The decoction without mechanical agitation was highlighted as the best method, from which the chemical characterization, antioxidant capacity and the presence of antinutrients were investigated. Three beverage formulations were prepared with coffee husk extract and added in different proportions to concentrated pineapple juice. The beverages were analyzed for antioxidant capacity, microbiological properties and sensorial acceptance. No hemagglutinins and low oxalate content were found in the samples. The antioxidant capacity of the aqueous husk extract was higher than that of the grains. The beverage made with the addition of concentrated pineapple juice was sensorially preferred by the tasters. On addition, it contributed to raise the antioxidant capacity of the beverage. Ot was concluded that the aqueous extract of coffee husk appears as a new alternative for the beverage industry.

The assesement of bioactive potential and sensory acceptability of coffee and its byproducts- cascara and silverskin

“…caffeine, are the most represented. Its positive effect on human health, as well as, stimulative related effects are well known (Das Neves et al, 2019). Valorization of cascara and silverkin in terms of extraction of bioactive compounds and its further implementation into various functional food products may have a noticeable potential on the market given the growing interest of consumers for polyphenol-rich "super foods" (Statista, 2020).…”

Coffee by-products derived resources. A review

“…Table 7 shows the antioxidant capacity of aqueous extract of coffee husk evaluated following DPPH (2,2-diphenyl-1-picryl-hydrazyl-hydrate) radical sequestration method and inhibition of co-oxidation of β-carotene and linoleic acid percentage [63]. For this experiment, coffee fruits were randomly collected at four different farm locations, from two plants in the northern (husk 1 and grains 1), southern (husk 2 and grains 2), eastern (husk 3 and grains 3), western (husk 4 and grains 4) and central region (husk 5 and grains 5) of the plantation [63]. Results indicated that micro-environmental conditions present in the plantation affect the antioxidant capacity of aqueous extract of coffee husk.…”

“…According to Tables 7 and 8, aqueous extracts of coffee husk represent a promising natural source of bioactive phytochemicals, also because of their low levels of antinutrients [63]. Neves et al [63] noticed that the beverage incorporated with concentrated pineapple juice presented the greatest acceptability, besides increasing the antioxidant capacity of the product. Thus, the formulated beverages constitute a promising alternative for the beverage market, given the meaningful content of phenolic constituents derived from coffee husk.…”

“…The sensorial analysis of flavor, aroma and overall appearance of the beverage developed with the rinds of coffee with different concentrations and pineapple juice [63]. For each column, means followed by different letters differ for P < 0.05, by the Tukey test.…”

Resultados a Partir De Equipamento Portátil E De Baixo Custo Desenvolvido Para Detecção De Adulterações Em Leite

“…No momento da colheita, foram coletados 20 capulhos aleatoriamente no terço médio das plantas nas duas linhas centrais de cada parcela e levadas ao laboratório para determinar a qualidade de fibra. A qualidade da fibra foi avaliada pela pelos seguintes parâmetros de: qualidade de fibra: Índice micronaire (Mic), Resistência expressa em tenacidade (Str), Índice da uniformidade do comprimento (Unf), Alongamento à rotura da fibra (Elg), Grau de reflectância (Rd), Índice de amarelamento (+b), Grau de cor (CG), Grau de folha (Leaf) , Percentual da área ocupada pelo somatório das partículas de impurezas em função da área total analisada (Area), Número de partículas maiores que 0,006m² presentes na superfície da amostra The values of TPC detected (2.33-3.28 gGAE100g ext, Table 1) were higher than those detected aqueous extracts of coffee husks (NEVES et al, 2019), and comparable or even lower than those obtained by hydroalcoholic extraction of coffee husks assisted with ultrasound, probably because of the highest exposure to acoustic cavitations that maximized the extraction of target compounds (RIBEIRO et al, 2019). On the other hand, the antioxidant capacity of extracts considering the DPPH assay (0.43-3.48×10 3 gTrolox eq/g extract or 0.14-1.16×10 3 gTrolox eq/g coffee husks - The condensed tannins (0.5-1.21 g catechin eq./100g extract or 0.16-0.40 g catechin eq./100g coffee husks -Table 1) detected in this work were next to those detected in the hydromethanolic extracts of leaves and flowers of Erodium glaoucophyllum (BAKARI et al, 2018) .…”