Juçara Fruit (Euterpe Edulis Martius) Valorization Combining Emergent Extraction Technologies and Aqueous Solutions of Alkanediols

Abstract

Anthocyanins from juçara fruits were extracted by pressurized liquid extraction (PLE) or ultrasound-assisted extraction (UAE), using aqueous solutions of 1,2-alkanediols and glycerol ethers as biobased solvents. The PLE (100 bar, 13 min, 1 mL/min flow rate) in the optimal extraction conditions originated 23.1 mg_anthocyanins·g_{dry biomass}^-1. On the other hand, the UAE was 10 min long, and the optimal conditions using 1,2-propanediol were 42.6 wt%, 160 W, and pH 7.0, leading to 50 mg_anthocyanins·g_{dry biomass}^-1. Extractions at the UAE optimized conditions, with aqueous solutions of five different 1,2-alkanediols and three glycerol ethers were performed, and compared to water and ethanolic extracts. The biobased solvent solutions presented anthocyanin yields up to 33% higher than water, and were shown to be as efficient as ethanol/water, but generated extracts with higher antioxidant capacity. The anthocyanin-rich extract of juçara, obtained with 1,2-propanediol, was used in the production of a natural soap and incorporated into a cream, showing that the addition of the juçara extract resulted in an antioxidant capacity in both products.

Keywords: 1,2-alkanediols; anthocyanins; glycerol ethers; pressurized liquid extraction; product formulation; ultrasound-assisted extraction.

Figure 1

Response surface plots obtained for the CCRD (2³) applying PLE regarding the alkanediol concentration (Calkanediol in wt%), temperature (°C), and pH in terms of yield of extraction of anthocyanins (mg_anthocyanins·g_{dry biomass}⁻¹). (A) C_alkanediol and Temperature, (B) pH and C_alkanediol, and (C) Temperature and pH.

Figure 2

Response surface plots obtained for the CCRD (2³) regarding the application of UAE, considering the alkanediol concentration (C_alkanediol in wt%), amplitude (%), and pH in terms of yield of extraction of anthocyanins (mg_anthocyanins·g_{dry biomass}⁻¹). (A) C_alkanediol and Amplitude, (B) pH and C_alkanediol, and (C) Amplitude and pH.

Figure 3

Comparison of different solvents in the extraction of anthocyanins (in terms of yield of extraction in mg_anthocyanins·g_{dry biomass}⁻¹) and their corresponding standard deviations. Purple bars represent the 1,2-alkanediols, and light pink bars represent the glycerol ethers studied. Different letters represent statistically different values (p ≤ 0.10), while the same letters represent statistically equal values (p > 0.10) by the Tukey test from ANOVA.

Figure 4

Juçara natural soap production. (A) Oil and butter heating; (B) melted butter and oil mixture; (C) soap mass before additives; (D) juçara extract (42.6% of 1,2-propanediol in 1:50 g/mL of juçara dried pulp); (E) parchment paper-lined molds filled with soap mass; (F) loaf of soap after 24 h; (G) soap bars; and (H) soap bars after cure.

Figure 5

Formulation creams evaluated in this work. (CC) Control cream; (JC) juçara cream; and (CJC) concentrated juçara cream.

Figure 6

Schematic design of the customized PLE unit: (1) Solvent reservoir; (2) solvent pump; (3) check valve; (4) pre-heater exchanger; (5 and 12) automatic temperature controller; (6 and 11) data acquisition by computer; (7) manometer; (8) thermocouple; (9 and 10) extraction vessel with electrical heating jacket; (13) regulator needle valve; (14) regulator valve; (15) block valve; and (16) amber glass flask.