Acca sellowiana: Physical-chemical-sensorial characterization and gastronomic potentialities

Comparison of Different Green Extraction Techniques Used for the Extraction of Targeted Flavonoids from Edible Feijoa (Acca sellowiana (O.Berg) Burret) Flowers

This study aimed to investigate the effect of four green extraction techniques (ultrasound-assisted extraction, UAE; supercritical fluid extraction, SFE; subcritical water extraction, SWE; and extraction using deep eutectic solvents, DES) on the extraction of targeted flavonoids from edible feijoa flowers. The bioactive components in the obtained extracts were quantified by High-Performance Liquid Chromatography-Photodiode Array Detector (HPLC-PDA). Moreover, total polyphenol content and antioxidant activity by DPPH^•, ABTS^•+, FRAP, and CUPRAC assays were investigated. UAE generally gave the highest yields for isoquercitrin and quercetin content (18.36-25.33 and 10.86-16.13 µg/g), while DES extraction with choline chloride:lactic acid (1:2) and H₂O content of 50% gave the highest yield of chrysanthemin (90.81 µg/g). The highest yield of flavone (12.69 mg/g) was obtained with supercritical CO₂ at 300 bar. Finally, UAE gave the highest total polyphenol content (ca. 64 mg GAE/g) and antioxidant activity at 70 °C during 30 min with 40% (0.84 mmol TEAC/g and 2.25 mmol Fe²⁺/g, for ABTS^•+ and CUPRAC, respectively) and 60% ethanol-water solution (0.49 mmol TEAC/g and 2.09 mmol Fe²⁺/g, for DPPH^• and FRAP, respectively). The eco-friendly extraction techniques resulted in selective methods capable of extracting targeted bioactive compounds from edible feijoa flowers.

Characterization of physicochemical properties, flavor volatiles and phenolic compounds of feijoa fruit varieties

Thirteen varieties of feijoa (Feijoa sellowiana) fruit were collected and the physical and chemical properties of feijoa peel, flesh, seed, and leaf were analyzed. Large diversities in the physicochemical characteristics and phenolic and volatile composition among various parts and between different varieties of feijoa were observed. Degrees Brix of whole fruits ranged from 10.1 (Anatoki) to 18.0 (No. 2) °Brix. Procyanidin B-type tetramer, procyanidin B-type dimer, and procyanidin C-type trimer had the highest concentrations in all parts and varieties of feijoa. Caffeoyl glucose, dihydroferulic acid 4-O-glucuronide, galloyl glucose, and lariciresinol-sesquilignan were detected in feijoa fruits and leaves. A total of 105 esters, 68 terpenes, 20 alcohols, 31 hydrocarbons, 12 aldehydes, and 11 ketones were related to aromatic attributes of fruits and leaves. Early season and mid-season varieties had larger variations in the chemical properties than late-season varieties. Anatoki, Kakariki, and No.1, have the potential to be developed for attractive flavor and functional properties.