Functionality Analysis of Spent Coffee Ground Extracts Obtained by the Hydrothermal Method

Abstract

Coffee is a popular beverage all over the world, but spent coffee grounds (SCGs) constituting almost 75% of original beans are usually considered waste and disposed off. e present study analyzed the functionalities of SCG with a view of its reuse in the cosmetic industry. e SCG extraction was carried out by the hydrothermal method. e resultant extracts were tested for its antioxidant capacity, tyrosinase inhibition, and moisturizing ability. LC-MS/MS results showed two major components in SCG extracts, namely, trigonelline and caffeine. Also, the SCG contained total flavonoid contents of 29 ± 4.5 mg quercetin equivalents (QE)/g SCG and total phenolic contents of 9.44 ± 0.90 mg gallic acid equivalents (GAE)/g SCG. Regarding functionality analysis, SCG extracts exhibited reduction capacity of 8.18 ± 0.39 mg vitamin C equivalent (VCE)/g SCG, DPPH free-radical scavenging activity (IC 50 ) of 3.11 mg SCG/mL, ABTS free-radical scavenging activity (IC 50 ) of 13.61 mg SCG/mL, and tyrosinase inhibition capacity (IC 50 ) of 2.23 mg SCG/mL. Moreover, the volatilization rate of the extract solution (37 mg SCG/mL) reduced by 15.9%. ese results demonstrate the utility of recycling of SCG and illustrate its potential application in the development of skin care products.

Effects of Storage Time and Temperature on Antioxidants in Juice from Momordica charantia L. and Momordica charantia L. var. abbreviata Ser.

“…The reducing power of the extracts was monitored according to the procedure described previously [ 27 , 30 , 32 ]. A 1-mL juice sample was mixed with 1 mL of 1% K 3 Fe(CN) 6 solution and 1 mL of phosphate buffer (2 mM, pH 6.6), which comprised Na 2 HPO 4 ·2H 2 O and NaH 2 PO 4 ·H 2 O.…”

“…DPPH scavenging activity was measured spectrophotometrically according to the method reported in previous papers [27][28][29][30][31][32]. The bitter gourd sample (2 mL juice sample) and the 0.08 mg/mL DPPH solution prepared with methanol (2 mL) were mixed together.…”

“…The reducing power of the extracts was monitored according to the procedure described previously [27,30,32]. A 1-mL juice sample was mixed with 1 mL of 1% K 3 Fe(CN) 6…”

“…TPC was determined according to the Folin-Ciocalteu colorimetric assay following the method described in previous reports [28][29][30][31][32][33]. The bitter gourd sample (1 mL juice sample) was added to 1 mL of 1N Folin-Ciocalteu reagent and 0.8 mL of 7.5% Na 2 CO 3 solution.…”

Plant Secondary Metabolites: An Opportunity for Circular Economy

“…PLE improves extraction yield, significantly reducing time and solvent consumption, [ 222 ] and it can be used to extract molecules of different polarity, such as phenolic compounds, carotenoids, and essential oils [ 222 ]. An optimized PLE protocol for the extraction of water-soluble molecules is represented by hydrothermal extraction, which uses water at high temperature and high pressure and has been employed to extract spent coffee grounds [ 223 ].…”