Minolta cr 400 colorimeter

The color and opacity were defined as described in Costa et al. [20 (link)]. A Minolta colorimeter (Cr 400; Minolta, Tokyo, Japan) was used to determine the films’ color. A white standard color plate (Y = 93.9, x = 0.3158, y = 0.3321) was used as a background for the instruments’ calibration, for color measurements of the films. The opacity of the samples was determined according to the Hunter lab method (Equation (2)). The measurements were repeated five times for each film.
$\mathrm{Opacity}=\frac{Y_b}{Y_w}\times 100$
where Y_b and Y_w are the opacity of each sample on a black and white standard, respectively.
Five measurements were performed for each film sample.

Instrumental color was evaluated using the CIELab color space (Konica Minolta colorimeter CR-400, Tokyo, Japan) for both UJJ and SJJ stored at 25 °C for up to 112 days, with 14-days intervals, and at 40, 50 and 60 °C for up to 56 days, with 7-days intervals.
Total color difference (ΔE*) during storage, between the initial storage time (t₀) and any given time (t_i), was calculated using the following equation: $\Delta E^{*}=\sqrt{{\left(L_{t_0}^{*}-L_{t_i}^{*}\right)}^2+{\left(a_{t_0}^{*}-a_{t_i}^{*}\right)}^2+{\left(b_{t_0}^{*}-b_{t_i}^{*}\right)}^2}$

Chlorophylls and carotenoids were determined according to Minguez-Mosquera et al. [18 (link)]. The samples of oil were dissolved with cyclohexane (1.5:5 w/v) and the absorbance was measured with a UV spectrophotometer (Pharmaspec UV 1700, Shimadzu, Kyoto, Japan). The chlorophyll and the carotenoid fractions were determined at 670 and 470 nm, respectively. The results obtained are expressed as mg of pheophytin ‘‘a’’ and lutein per kg of oil, respectively.
Instrumental colour (CIE L*, a*, b*) was measured directly in the olive oil samples using a Minolta Colorimeter (CR-400, Konica Minolta Corp., Bremen, Germany) with illuminant D65, as described in Borges et al. [19 (link)].

The color of the HACS, hydro-micro-HACS, and composite was measured using a Konica Minolta colorimeter CR-400 (Osaka, Japan) and the L*(the degree of lightness), a*(the red-green axis), and b* (the yellow-blue axis) values were recorded.

The measurement of the color of the baked cakes and rusks was performed using an automatic Konica Minolta colorimeter CR-400 with Spectra Magic NX 1.3 software (Osaka, Japan). Prior to the measurements, the equipment was calibrated using a standard white tile. The color of ground baked cake and rusk samples was measured in triplicate at several points for each sample. The color parameters (i.e., L*—brightness (from 0—black to 100—white), a*—(from (−50)—green to 50—red), b*—(from (−50)—blue to 50—yellow), and dE value, equal to the square root of [(dL*)2 + (da*)2 + (db*)2], characterizing the total change in color were measured. The obtained values were equivalent to the total color difference, whether obvious or not to the human eye, according to Bodart et al. [41 (link)]: dE* < 1, color differences are not obvious to the human eye; 1 < dE* < 3, minor color differences could be appreciated by the human eye depending on the hue; and dE* > 3 color differences are obvious to the human eye.
The browning index (BI) of the baked cakes and rusks was determined according to Wen and Chih [42 ].