Reducing toxic constituents of ginkgolic acid content and improving bioactive flavonoid content from Ginkgo biloba leaves by high-temperature pretreatment processing

Thermal fixation technologies affect phenolic profile, ginkgolides, bilobalide, product quality, and ginkgolic acids in Ginkgo biloba leaf tea

Ginkgo biloba leaves (GBLs) contain high phytoconstituents, but ginkgolic acids (GAs, the main toxic compound in GBLs) have limited its applications. Processing Ginkgo biloba dark tea (GBDT) using fixation technology could decrease the toxic compounds; retain flavonoids, ginkgolides, and bilobalide; and improve the product quality. For the first time, various thermal fixations (hot air fixation [HAF], iron pot fixation [IPF], and boiled water fixation [BWF]) followed by rolling, fermentation, and drying were applied to produce GBDT. A comprehensive analysis of the toxicants (GAs), main bioactive compounds (ginkgolides and bilobalide, flavonoids, antioxidants, and phenolic profiles), and product qualities (moisture content, reducing sugar [RS], free amino acids [FAAs], enzyme activity, color properties, antioxidant capacity, etc.) were evaluated. The results revealed that thermal fixations BWF and HAF significantly reduced the GA contents (41.1%-34.6%). Most terpene lactones showed significant differences in control, IPF, and HAF. The HAF had lower total flavonoid content (TFC) than BWF and IPF. The control group (unfixated) had the highest toxic components (GA), terpene trilactones, and TFC compared with various fixations. Adding different fixations to rolling, fermentation, and drying had various impacts on GBDT, and principal component analysis supported the results. Among four thermal fixations, HAF yielded the best results in RS, FAA, total phenolic content, and antioxidant activities, while IPF had the highest TFC. BWF had the lowest content for GA. In conclusion, HAF (6) was chosen as the best technique for producing GBDT since it preserved GBDT's bioactive components while lowering its toxic components.

Isolation of phenolic compounds from eco-friendly white bee propolis: Antioxidant, wound-healing, and anti-Alzheimer effects

This study presents the first findings regarding extraction, isolation, enzyme inhibition, and antioxidant activity. The oral mucosal wound-healing process was investigated using propolis water extract (PWE) incubation with gingival fibroblast cells and concluded that propolis was effective on the oral mucosal wound-healing pattern compared to untreated controls. Additionally, phenolic compounds (fraxetin, apigenin, galangin, pinobanksin, chrysin, etc.) were isolated from propolis, and their chemical structures were elucidated using comprehensive spectroscopic methods. The antioxidant and anti-Alzheimer potential activities of PWE and some isolated compounds were screened and revealing their inhibitory effects on acetylcholinesterase (AChE) with IC50 values ranging from 0.45 ± 0.01 to 1.15 ± 0.03 mM, as well as remarkable free-radical scavenging and metal reduction capacities. The results suggest that these compounds and PWE can be used as therapeutic agents due to their antioxidant properties and inhibitory potential on AChE. It can also be used for therapeutic purposes since its wound-healing effect is promising.

Optimization of sonication time, edible coating concentration, and osmotic solution °Brix for the dehydration process of quince slices using response surface methodology

The goal of this work was to examine the effects of sonication time, edible coating concentration (with guar gum), and °Brix (sucrose solution) on the osmotic dehydration (OD) parameters (mass reduction, water loss, soluble solids gain, and rehydration ratio) and the appearance properties (color indices and surface area) of quince slices using a response surface methodology (RSM) approach based on the central composite design (CCD), for the optimization of the process. The process parameters, sonication treatment time (5-10 min; 40 kHz and 150 W), edible coating concentration using guar gum (0.05%-0.15%, w/w), and osmotic concentration using sucrose solution (20%-50%, w/w), were investigated and optimized for OD of quince slices. After each OD process, the quince slices were dehydrated in an oven at 70°C for 240 min. Results demonstrated a good correlation between empirical data with the linear model. Using the optimization method, optimum input operating conditions were determined to be a sonication time of 5 min, guar gum concentration of 0.05%, and sucrose concentration of 37.19°Brix. At this optimum point, the OD process of quince slices reached the optimal mass reduction (17.74%), water loss (25.77%), soluble solids gain (8.03%), rehydration ratio (206.19%), lightness (77.6), redness (0.60), yellowness (34.84), total color change (ΔE) (8.92), and area changes (7.59%).