Integrated study on bioactive potential, solvent polarity optimization, and encapsulation of phenolic rich compounds from Iraqi desert truffles

This study explored two truffle species, Tirmania spp. and Terfezia claveryi, collected from five newly identified geographical locations in Iraq, with a focus on their nutritional and medicinal value. For this purpose, an experimental design was used, and various methods were employed to extract truffle mushrooms, including conventional extraction, microwave-assisted extraction, maceration, and supercritical CO₂ extraction. The macerated extracts were powdered using freeze-drying techniques, which are the most effective among the extraction techniques. In encapsulation, mixtures of maltodextrin and gum arabic were used as the wall material. The yield extract, brix, total phenolic content, flavonoids, anthocyanins, condensed tannins, and chemical compositions—analyzed using LC-MS/MS and GC-MS—were examined for phenolic compounds, as well as aroma and volatile components of the extracts. Determine the Trolox of antioxidant activity, such as DPPH, ABTS, and CUPRAC, as well as the percentage and IC50 values. Antibacterial activity, evaluated using the agar well diffusion method, showed significant inhibition against various types of bacteria. A significant challenge in the extraction process is determining the most suitable solvent to maximize bioactivity, which is influenced by polarity indices. Optimization of the extraction analysis was conducted using response surface methodology. A comprehensive evaluation of solvents with polarity indices (SPI: 0.1: Hexane, 2.65, Hexane+Ethanol, 5.2: Ethanol, 7.7, Ethanol+water, and 10.2: water) revealed that polarity played a crucial role, particularly in maceration extraction, which resulted in lower energy barriers and higher antioxidant activity. Moreover, microwave-assisted extraction showed the best efficiency at (8.4 SPI-150 watts), conventional extraction at (6.7 SPI-87 min), maceration at 10.2 SPI, and SP-CO₂ at (200 bar-30°C) with high desirability. Water and ethanol demonstrated superior extraction of bioactive compounds compared to n-hexane. While the water extract exhibited high antioxidant activity, the ethanol extract was optimal for phenolic and flavonoid content due to its polarity indexes. Moreover, among all extraction methods, the supercritical extracts in 200 bar and 30 °C showed the strongest effect against E. coli and Staphylococcus aureus. Furthermore, LC-MS/MS analysis revealed that fumaric acid and vanillic acid were the major compounds, with Tirmania spp. generally exhibiting higher concentrations than Terfezia claveryi. Principal component analysis and hierarchical clustering revealed distinct bioactive profiles among samples. For the physicochemical analysis of powders that were converted into nanocapsule form, water activity, total yield, bulk density, tapped bulk density, wettability, Carr index, Hausner ratio, total antioxidant activity, phenolic content, flavonoid content, and their morphological properties (assessed by scanning electron microscopy, SEM) were analyzed. Additionally, it has been determined that physical analysis tests for optimum powder properties are more acceptable in the powders obtained with a 60%MD/40%GA ratio and 12.45 g of wall material.