Multiresponse Optimization and Prediction of Antioxidant Properties of Aqueous Ginger Extract

Bioactive characterization of ultrasonicated ginger (Zingiber officinale) and licorice (Glycyrrhiza Glabra) freeze dried extracts

Ginger (Zingiber officinale) and Licorice (Glycyrrhiza glabra L.) are one of the most popular spices having a wide range of bioactive compounds that have varied biological and pharmacological properties. The study was aimed to extract polyphenols from Himalayan medicinal herbs ginger and licorice in different solvents using ultra-sonication technique. The extraction efficiency (EE) was determined, and the extracts were characterized for physical properties (particle size, colour values), total phenolics, flavonoids, antioxidant properties, and structural and morphological features. Ultra-sonicated ginger in aqueous phase had the highest EE of polyphenols (15.27%) as compared to other solvents. Similar trend was observed in licorice with EE of 30.52 % in aqueous phase followed by ethanol: water (50: 50), and methanol: water (50:50) with 28.52% and 26.39%, respectively. The preliminary screening showed the presence of tannins, phenolics, flavonoids, saponins and carbohydrates, steroids and alkaloids in all the extracts. The phenolic and flavonoid content of dried ginger was found higher in ethanolic extracts compared to fresh ones as revealed by HPLC. Similarly, for licorice, the ethanolic fractions had the highest polyphenolic content. The representative samples of ginger (ethanol: water 75:25 and ethylacetate: water 75:25) and licorice (ethanol: water 70:30 and methanol: water 50:50) were studied for FESEM and particle size. The results showed the agglomerated extract micro-particles with a diameter of 0.5-10 µm and increased particle size (ginger: 547 and 766 nm), and (licorice: 450 and 566 nm). The findings could be beneficial for the advancement of ginger and licorice processing, for the comprehension of these herbs as a source of natural antioxidants in different food formulations.

Enhancing Sensory Perception of Plant Based Nutraceutical Drinks by Combining Plants from Different Sources: A Preliminary Study of Tea and Ginger Blend

Tea-ginger drink was selected for evaluation due to its nutraceutical potential. Panelists rated preference for drinks prepared from tea, ginger, and tea+ginger powder for colour, taste, and aroma. The obtained data were evaluated using analysis of variance, principal component analysis, and agglomerative hierarchical clustering. Also the colour preference scores were evaluated against instrumental colour measurements. The ginger drink had lower rating for colour preference and the tea drink had lower ratings for aroma and taste preference. However, the tea-ginger drink led to enhanced colour, aroma, and taste ratings. The colour preference was found to have highest correlation coefficient with the hue and chroma of the drinks [r(58)=-0.583, P<0.05 and r(58)=0.566, P<0.05]. This study suggests that a sensory quality deficiency in a particular plant based drink could be compensated for by blending the drink with another plant based drink. This approach could help improve the uptake of plant based nutraceutical drinks.

Influence of particle size and extraction solvent on antioxidant properties of extracts of tea, ginger, and tea-ginger blend

The influence of particle size and extraction solvent on the antioxidant properties of aqueous and ethanolic extracts of tea (Camellia sinensis), ginger (Zingiber officinale), and tea–ginger (2:1) blend was investigated. The powder sizes studied were 0.425, 0.710, and 1.180 mm. Extracts were analyzed for DPPH radical scavenging activity, ABTS radical scavenging activity, total phenol content (TPC), iron chelating activity, total flavonoid content, and peroxide scavenging activity. The powder with the lowest particle size of 0.425 mm tends to produce aqueous extracts of tea, ginger, and tea–ginger with highest antioxidant content. At this lowest particle size all the antioxidant properties assayed were maximized. The TPC of aqueous extracts obtained from the 0.425 mm tea, ginger, and tea–ginger powders were 685.44 ± 175, 283.58 ± 19, and 483.02 ± 176 mg gallic acid equivalent (GAE) L⁻¹, respectively. The TPC of aqueous extracts obtained from the 0.710 mm tea, ginger, and tea–ginger powders were 679.06 ± 169, 208.94 ± 147, and 400.10 ± 130 mg GAE L⁻¹, respectively. However, for the aqueous ethanolic and ethanolic extracts, the particle size that maximized the antioxidant extraction varied depending on the antioxidant property that was being assayed. The study suggests that particle size influences the extraction of antioxidants. Also, the optimum powder size that would maximize antioxidant extraction is dependent on the solvent used and the antioxidant property being measured.