Impact of Cold Atmospheric Plasma Pretreatment on the Recovery of Phenolic Antioxidants from Spent Coffee Grounds.

In the present study, cold atmospheric plasma (CAP) was employed as a pretreatment method for the extraction of phenolic compounds from spent coffee grounds (SCGs). The impact of CAP treatment conditions, i.e., thickness of the SCGs layer (mm), distance between the plasma source and the SCGs layer (mm) and duration of CAP treatment (min), on the total phenol content, in vitro antioxidant activity, as well as caffeine and chlorogenic acid content of SCGs, was investigated. The process parameters were optimized with the aid of response surface methodology (RSM). After optimizing the CAP pretreatment conditions, the CAP-treated SCGs were subjected to ultrasound-assisted extraction using ethanol as the extraction solvent. The optimum conditions for CAP treatment identified, i.e., thickness, 1 mm; distance, 16 mm; and duration, 15 min, led to a significant enhancement in the recovery of bioactive compounds from SCGs compared to those obtained from untreated SCGs. Total phenolic content and antioxidant activity significantly increased (i.e., TPC from 19.0 ± 0.7 to 24.9 ± 1.4 mg GAE/100 g dry SCGs, ADPPH from 106.7 ± 5.01 to 112.3 ± 4.3 µmol Trolox/100 g dry SCGs, AABTS from 106.7 ± 5.01 to 197.6 ± 5.8 µmol Trolox/100 g dry SCGs, ACUPRAC from 17938 ± 157 to 18299 ± 615 µmol Trolox/100 g dry SCGs). A significant increase in caffeine content from 799.1 ± 65.1 mg to 1064 ± 25 mg/100 g dry SCGs and chlorogenic acid content from 79.7 ± 15.3 mg to 111.3 ± 3.3 mg/100 g dry SCGs, was also observed. Overall, CAP pre-treatment can be used to enhance the recovery of bioactive compounds from SCGs.

Coupling of cold atmospheric plasma treatment with ultrasound-assisted extraction for enhanced recovery of bioactive compounds from cornelian cherry pomace.

Cornelian cherry pomace is produced during the production of juice from this traditional superfood. Due to its high nutritive value, the by-product can be utilized as a source of bioactive compounds. The present study aimed to develop a sustainable methodology for the recovery of bioactive compounds based on the combination of atmospheric cold plasma (CAP) with ultrasound assisted extraction. The pomace was treated with cold plasma under different conditions. Cyclodextrin was used as green extraction enhancer due to its capacity to develop inclusion complexes with bioactive compounds. CAP pretreatment before extraction appeared to enhance the recovery of the target compounds. GC-MS analysis and in vitro digestion analysis conducted in order to evaluate the composition and the protentional bioavailability of the bioactive compounds. CHEMICALS COMPOUNDS: ß-cyclodextrin (PubChem CID: 444041), DPPH free radical (PubChem CID: 2735032), Trolox (PubChem CID: 40634), sodium carbonate (PubChem CID: 10340), gallic acid (PubChem CID: 370) potassium chloride (PubChem CID: 4873), sodium acetate (PubChem CID: 517045), loganic acid (PubChem CID: 89640), pyridine (PubChem CID: 1049, BSTFA(PubChem CID: 94358), potassium chloride (PubChem CID: 4873), ammonium carbonate (PubChem CID: 517111), calcium chloride dehydrate (PubChem CID: 24844), potassium dihydrogen phosphate (PubChem CID: 516951), magnesium chloride hexahydrate (PubChem CID: 24644), sodium hydrogen carbonate (PubChem CID: 516892), sodium chloride (PubChem CID: 5234).