• Food Science and Preservation
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• v.30 no.2
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• pp.224-234
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• 2023

We analyzed the major quality characteristics of red pepper powders from various regions and predicted these characteristics nondestructively using shortwave infrared hyperspectral imaging (HSI) technology. We conducted partial least squares regression analysis on 70% (n=71) of the acquired hyperspectral data of the red pepper powders to examine the major quality characteristics. R_c² values of ≥0.8 were obtained for the ASTA color value (0.9263) and capsaicinoid content (0.8310). The developed quality prediction model was validated using the remaining 30% (n=35) of the hyperspectral data; the highest accuracy was achieved for the ASTA color value (R_p²=0.8488), and similar validity levels were achieved for the capsaicinoid and moisture contents. To increase the accuracy of the quality prediction model, we conducted spectrum preprocessing using SNV, MSC, SG-1, and SG-2, and the model's accuracy was verified. The results indicated that the accuracy of the model was most significantly improved by the MSC method, and the prediction accuracy for the ASTA color value was the highest for all the spectrum preprocessing methods. Our findings suggest that the quality characteristics of red pepper powders, even powders that do not conform to specific variables such as particle size and moisture content, can be predicted via HSI.

• Korean Journal of Food Science and Technology
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• v.25 no.5
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• pp.417-420
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• 1993

Changes in color intensity of Hololeion maximowiczii(HM) roots which were treated with freeze drying (FD), $50^{\circ}C$ hot air drying (HAD) and $50^{\circ}C$ hot air drying after steam blanching (HADB) were investigated in this study. Color of HADB was yellow-green while other treatments showed bright brown color. In brown color intensity, optical density at 420 nm of FD treatment was highest but HADB treatment showed the highest value in ultra violet spectrum. Water soluble pigment of HM in state of aquous solution was more unstable for heat treatment than that in state of powder. Activation energy for decomposition of the pigment was 20.9 kcal/mole between $90{\sim}100^{\circ}C$ but 50.6 kcal/mole between $80{\sim}90^{\circ}C$.

• Natural Product Sciences
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• v.1 no.1
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• pp.66-69
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• 1995

Traditional Antheraea pernyi silkworm cocoon is tawny color. The white Antheraea pernyi silkworm cocoons studied here by IR and UV are new breeds of recent breeding. We discovered that the main body of the first grade structure of silk protein in the new white is as same as the one in the traditional tawny Antheraea pernyi silkworm cocoon, yet there are small quantities of cross-linked polymer of gentisic acid and silk protein in the white silkworm cocoons. In spite of the least surviving quantity of the polymer, the white silkworm cocoons are most white and its white color is similar to white Bombyx mori silkworm cocoon.

• Journal of the Korean Society of Food Science and Nutrition
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• v.14 no.2
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• pp.117-122
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• 1985

The effects of various factors on the color stability of plum nectar were studied. The data showed that pH and temperature were the most important factors affecting the rate of color loss. The concentration of ascorbic acid affected the rate of color loss in plum nectar. Although the color loss could be influenced by the presence of sugars and their degradation products such as 5-hydroxymethyl-2-furfural(HMF), HMF did not accumulate in sufficient amounts during the storage in the plum nectar to affect appreciably the degradation rate. The pigment was very unstable in the fermented juice and its. spectrophotometric spectrum was changed differently from that of natural plum color material. Materials present in plum nectar itself apparently have an appreciable effect on the rate of color loss.

• Environmental Engineering Research
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• v.23 no.2
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• pp.205-209
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• 2018

The spectral composition of light can affect the growth and biochemical composition of photosynthetic microalgae. This study examined the use of light filtering through a solution of soluble colored additives, a cost-effective method to alter the light spectrum, on the growth and lipid production of an oleaginous microalga, Nannochloropsis gaditana (N. gaditana). Cells were photoautotrophically cultivated under a white light emitting diode (LED) alone (control) or under a white LED that passed through a solution of red and yellow color additive (4:1 ratio) that blocked light below 600 nm. The specific growth rate was significantly greater under filtered light than white light ($0.2672d^{-1}$ vs. $0.1930d^{-1}$). Growth under filtered light also increased the fatty acid methyl ester (FAME) yield by 22.4% and FAME productivity by 80.0%, relative to the white light control. In addition, the content of saturated fatty acids was greater under filtered light, so the biodiesel products had better stability. These results show that passing white light through an inexpensive color filter can simultaneously enhance cellular growth and lipid productivity of N. gaditana. This approach of optimizing the light spectrum may be applicable to other species of microalgae.

• Journal of the Korean Society of Food Science and Nutrition
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• v.26 no.1
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• pp.60-66
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• 1997

The characteristics and stability of pigments produced by Monascus anka in a jar fermenter were examined The pigments produced by the mold were fractionated into four pigments, i.e., extracellular red pigment(ERP) extracellular yellow Pigment(EYP), intracellular red pigment(IRP) and intracellular yellow pigment(IYP) by the solvent fractionation method. These pigments showed characteristic absorption spectrum indicating that they were composed of different components of pigments. Each of these four pigments separated from Monascus anka were stable under ultraviolet light, fluorescent light and in dark conditions, but their color was faded rapidly under sun light. They were also very stable against temperature below 8$0^{\circ}C$, above which temperature the stability of the Pigments was decreased rapidly. Among the eight organic acids tested, tartaric and citric acids were found to be detrimental against the Monascus anka Pigments. And Cu$^{2+}$ ion showed the most deleterious effect on the color change of the pigments.s.

• Journal of the Korean Applied Science and Technology
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• v.10 no.1
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• pp.93-101
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• 1993

This study aimed to search for separate and identify of Quercus acutissima CARRUTHERS tannins. Tannins were extracted with methanol and ethylacetate from acorn powder and identified TLC, UV spectrum, HPLC, IR, GC/MS, and $^{1}H$ NMR. Three spots($R_{f}$ 0.94, 0.84 and 0.29) detected on TLC. These spots gave dark blue color fairly on spraying with 0.3% potassium ferricyanid${\cdot}$0.3% ferricchloride reagent, and these tannins identified as gallic acid, caffeic acid and ellagic acid by UV spectrum, HPLC, IR, GC/ MS, and $^{1}H$ NMR.

• Journal of Marine Bioscience and Biotechnology
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• v.16 no.1
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• pp.19-25
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• 2024

To verify the color change in dried laver postproduction during the heating process, chromaticity elements were compared via a spectrophotometer across various heating conditions within the visible light spectrum. In general, the moisture reduction rate increased with rising temperature and time. Surface image comparisons revealed an expanded area of light reflection on the heat-treated dried laver sample due to surface roughening from shrinkage. No statistically significant differences in chromaticity values were observed in the measurements of brightness (L^*), redness (a^*), and yellowness (b^*). Reflectance spectrum measurements in the visible light region confirmed high reflectance under red wavelength conditions. In particular, a significant increase in reflectance at 700 nm compared with untreated samples was noted. The correlation between the increase in 700 nm reflectance of dried laver samples and heating conditions ranged from 0.7471 to 0.7793, suggesting its potential use as an indicator for comparing color changes in dried laver based on heating conditions.

• Journal of the East Asian Society of Dietary Life
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• v.26 no.4
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• pp.314-324
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• 2016

To improve the color stability of chlorophyll in young barley leaf used as functional green biomaterial, the absorption spectrum, color values, and antioxidative activities of young barley leaf (YBL) treated with zinc ion solutions were investigated. The small pieces of fresh YBL in aqueous solution mixtures were autoclaved twice at $110^{\circ}C$ for 30 min (pH 5). Distilled water (BLA), 0.01% zinc chloride (BLAZ), 0.01% zinc citrate (BLAC), and 0.01% zinc lactate (BLAL) solutions were used. Treated YBL powders were extracted with 80% EtOH for 4 h. Chlorophyll a and b contents differed with different treatments. BLA decreased chlorophyll a and b contents, whereas others were maintained. Absorbance spectrums of chlorophyll at 400~700 nm showed different maximum peak wavelengths. After heating in acidic and neutral solutions (pH 3, 5, and 7), the colors of YBL and BLA changed from green to olive green, whereas BLAZ, BLAC, and BLAL remained green color. The antioxidative activities showed higher values in YBL extract than in treated extracts. From the above results, autoclaved YBL in zinc solution would increase the color stability and maintain green color regardless of acid and heat treatments.

• Food Science and Preservation
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• v.3 no.1
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• pp.23-32
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• 1996

Total carotenoid contents, color values and spectrum characterization in the range of UV of fruit juice and organic acid and free sugar contents determined by HPLC were investigated on 10 varieties of Cheju citrus fruits. Carotenoid contents of juice were 0.47-9.20$\mu\textrm{g}$/ml which showed higher with Dangyooja while showed lowest content with Meiwa Kumquat. Lightness (L) of juice was highest in Meiwa Kumquat, and in the order of Sankyool, Navel orange and Hungjin. Redness(a) and yellowness(b) were in the order of Dangyooja, Natsudaidai, Sambokam and Kinkoji. The maximum absorption wavelengths if citrus Juices were variable at 269.5-285.5nm according to varieties and it was observed that were changed by mixing with Juices of other varieties. Major organic acids of citrus juice were citric and malic acid, and citric acid was 64.4-95.1% of total organic acids. Ascorbic acid was high in Navel orange, Sudachi and Dangyooja, and low in Meiwa Kumquat and Hungjin. Major free sugars were sucrose, glucose and fructose. Sucrose was 49.2-75.2% of total free sugars, and high in Sankyool and Meiwa Kumquat. Glucose and fructose were high in Meiwa Kumquat and Navel Orange.