Colorquest xe

The chroma values (L₀*, a₀*, b₀*) of ion-exchanged permutite were measured by colorimeter (ColorQuest XE, Hunter Lab, Reston, VA, USA). The permutite samples were treated in a 254 nm UV irradiation box for of 5 cycles of 4 h, and measured again (L₁*, a₁*, b₁*). In hunter whiteness formula, the whiteness of the fully reflected diffuser was defined as 100, and the whiteness of the sample was compared with the whiteness of the fully reflected diffuser. The whiteness of the sample was evaluated by calculating the color difference [18 (link)]. The hunter whiteness formula was calculated using Equation (1): $W(L*,a*,b*)=\sqrt{{(100-L)}^2+{(a*)}^2+{(b*)}^2}$
The discoloration properties of permutite samples were evaluated by the total color difference, as given by Equation (2) [19 (link)]: $\Delta E=\sqrt{{(L_0^{*}-L_1^{*})}^2+{(a_0^{*}-a_1^{*})}^2+{(b_0^{*}-b_1^{*})}^2}$
The nitrogen adsorption-desorption isotherms were measured by the volumetric method on an automatic adsorption instrument (ASAP 2010, Micromeritics, Norcross, GA, USA). The pore structure of permutite samples was analyzed by means of nitrogen sorption at 77.36 K. Specific surface area was calculated by the Brunauer-Emmett-Teller (BET) method based on the data in the p/p₀ range between 0.05 and 0.25. A Barrett-Joyner-Halenda (BJH) analysis was carried out to calculate the mesopore volumes.

The colour of dried materials was determined using the CIELab system. The colour of the gooseberry fruits was measured with ColorQuest XE (Hunter Lab). Milled fruits were placed in a glass cuvette, and the colour was recorded using CIE L*a*b* 10°/D65 colour spaces, where L* indicates lightness, a* is the +a redness, and b* is the +b yellowness.

The colorimeter (ColorQuest XE, HunterLab Inc.) was used to measure the color of the coffee bean (25 (link)). The colorimeter was calibrated using the white plate and packed coffee powder was added to a transparent preservative film and then placed on the detection port to obtain data. Results were calculated by the equipment using the Hunter Lab color scale. In this scale, L ranges from 0 (black) to 100 (white), a indicates degree of greenness (for negative a values) and degree of redness (for positive a results), b axis also ranges from negative to positive values indicating, respectively, degree of blueness to yellowness.

The Color Quest XE machine (Hunter Lab, Reston, VA, USA) was used to investigate the film’s color, according to the modified approach of Choi, et al. [29 (link)]. The L* (lightness), a* (red-green), and b* (yellow-blue) values of the film were recorded.

The red saturation (a*) and yellow saturation (b*) of the peel were measured using a Color Quest XE color difference meter (Hunter Lab, Reston, VA, USA) on both sides of the abdomen of the fruit suture, and the ratio of red-green difference/yellow-blue difference was calculated (a*/b*). The average of two points was used as the corresponding index value of the fruit. The content of chlorophyll (Chl) in the pericarp was determined using the method of Lichtenthaler and Wellburn [15 (link)], followed by extraction with 95% ethanol and measuring the absorbance at 665 and 649 nm. The anthocyanin (Ant) content was determined in accordance with the method of Zapsalis and Francis [16 (link)], followed by extraction with 1% methanol solution of hydrochloric acid, and measuring the absorbance values at 650, 620 and 530 nm. Then, the content was calculated.

Colors of the hot and cold brew coffee were measured using a spectrophotometer (Hunterlab ColorQuest XE) at the transmission mode, D65 illuminant, 0.375 inch observation aperture, and 10° observation angle. A cuvette with a light path of 5 mm was applied in this study. The L*a*b* values of hot and cold brew coffee samples were determined after calibration. L* represents lightness, and a* and b* are chromaticity indexes. The total color difference (ΔE) of the two coffee was calculated via
$$\mathsf{\Delta }\mathrm{E}=\sqrt{{({{\mathrm{L}}^{*}}_{\mathrm{cold}}- {{\mathrm{L}}^{*}}_{\mathrm{hot}})}^2+{({{\mathrm{a}}^{*}}_{\mathrm{cold}}-{{\mathrm{a}}^{*}}_{\mathrm{hot}})}^2+{({{\mathrm{b}}^{*}}_{\mathrm{cold}}-{{\mathrm{b}}^{*}}_{\mathrm{hot}})}^2}$$