Hunter lab colorimeter

The color of all samples (control and Fe-fortified) from split desi seeds (dal), desi flour and kabuli flour was evaluated using a HunterLab Colorimeter (Hunter Associates Laboratory Inc., Reston, VA, USA). Iron-fortified samples were compared to unfortified controls. The color values (L*, a* and b*) for each sample were recorded at three-month intervals over a one-year period [32 ].
The fortified desi and kabuli flours along with controls were assessed for rancidity. The samples were stored individually for 6 and 12 months in plastic bags at room temperature (19–22 °C) and a relative humidity of 45%–55%. The moisture contents ranged from 8.3%–9.3%. Five-gram samples were weighed and transferred into test tubes, followed by the addition of 50 mL of methylene chloride to each tube. The flour and methylene chloride mixture was pressed in a syringe and enough oil–solvent mixture collected to recover approximately 1g of oil. The solvent was removed using a rotary evaporator (BUCHI Rotavapoor R-200, Brinkmann Instruments, Inc., Westbury, NY, USA) and the oil was transferred to a 5 mm diameter NMR tube [33 (link)]. The samples were analyzed in an NMR spectrometer (Ultrashield 500 MHz/54 mm, Bruker AG, Fallanden, Switzerland) for 1 h to obtain a signal for hydroperoxide, the primary product of lipid oxidation [34 (link)].

Color characteristics, including lightness (L*), redness (a*), and yellowness (b*), were recorded at random points on the fried SDEW instant noodle with the aid of the Hunter LAB colorimeter (Hunter Associates Laboratory, Inc., Reston, VA, USA). The total color characteristics of the noodles were calculated using the L*, a*, and b* values by following the equation proposed by Tiga et al. [56 (link)].
$$\Delta {\mathrm{E}}^{*}=\sqrt{\Delta {\mathrm{L}}^{*2}+\Delta {\mathrm{a}}^{*2}+\Delta {\mathrm{b}}^{*2}}$$
where $\Delta$ L*, $\Delta$ a*, and $\Delta$ b* represents the lightness, redness, and yellowness of the color characteristics of the SDEW instant noodles, respectively. $\Delta$ E* is the total color value.

The color analysis of the EC was performed using a HunterLab colorimeter (HunterLab, Reston, VA, USA), which employs a D65 illuminant to simulate daylight. The color was expressed in terms of the L*, a*, and b* parameters according to the CIELab scale. The color difference (∆E*) between the ECC and the control FS was calculated using Equation (6).
$${∆E}^{*}=\sqrt{{{(\mathrm{∆}L}^{*})}^2+{{(\mathrm{∆}a}^{*})}^2{{+(\mathrm{∆}b}^{*})}^2}$$
where:

∆E*: Total color difference between the ECC Sample and the base color standard FS.

(∆L*): Difference in luminosity between the ECC sample and the base color standard FS.

(∆a*): Shift in the green-red color between the ECC sample and the base color standard FS.

(∆b*): Shift in the blue-yellow color between the ECC sample and the base color standard FS.

The cooked noodles were freeze-dried and milled through 60 mesh (HY-04A, Beijing Huanyatianyuan Instrument Co., Ltd., Beijing, China). The color of the cooked noodle powder was measured by a HunterLab colorimeter (DP-9000 D25A, Hunter Associates Laboratory, Reston, VA, USA) with a 40 mm aperture and a halogen tungsten lighting source lamp equipped with a C illuminant and 2° standard observer. The results were expressed as L* (lightness/darkness), a* (greenness/redness) and b* (blueness/yellowness) values. The instrument was calibrated with standard whiteboards and blackboards. Color value averages were calculated from triplicate measurements. The ΔE value representing the comprehensive value of the noodle was calculated as follows: