Heliyon (Dec 2022)
The effects of extraction conditions on the antioxidant activities, total polyphenol and monomer anthocyanin contents of six edible fruits growing wild in Hungary
Abstract
Although wild fruits are significantly underutilized in most countries, they could be good sources of valuable bioactive compounds with antioxidant properties. Therefore the present study focused on the study of a conventional extraction technique (maceration with shaking; MACS) to extract natural antioxidants and anthocyanin colorants from six edible wild-growing fruits (European crab apple, bilberry, yellow-, red-, and purple-skinned greengage, and quince). One-factor-at-a-time (OFAT) methodology was chosen to investigate the influences of three different parameters (solvent type, extraction time and solvent acidity) on the total polyphenol contents (TPCs), total monomeric anthocyanin (TMA) contents, and antioxidant capacities, specifically ferric reducing power (FRAP) and 2,2-diphenyl-1-picrylhydrazyl radical-scavenging activity (DPPH). After optimization, the recorded TPCs and antioxidant activities proved to be significantly higher for all analyzed fruits when compared to differing extraction conditions. For European crab apple and purple-skinned greengage, the best extraction conditions were a ratio of 80:20 (v/v) EtOH–H2O, 1% (v/v) of HCOOH, and an extraction time of 90 min. In the case of red-skinned greengage, the extraction parameters were the same as the above except for the acid concentration (0.5%; v/v) used. For quince, the optimized conditions required a 50:50 (v/v) EtOH–H2O mixture, an extraction time of 90 min, and 0.5% (v/v) HCOOH concentration. The best conditions for the extraction of bilberry and yellow-skinned greengage were an EtOH–H2O combination of 50:50 (v/v), extraction time of 60 min, and HCOOH concentration of 0.5% (v/v). The highest TPC and antioxidant activity were observed in quince (281–510 mg GAE/100g and 109–395 mg AAE/100g) whereas the lowest were measured in European crab apple (55.9–70.0 mg GAE/100g and 20.1–43.2 mg AAE/100g). Bilberry exhibited the highest TMA content (346 mg CGE/100g). Overall, our results showed that these wild fruits could be a good source of natural antioxidants for the local residents.
