Hue Angle (hue + angle)

Distribution by Scientific Domains


Selected Abstracts


Phenolic compounds and the colour of oranges subjected to a combination treatment of waxing and irradiation

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 13 2004
Mostafa Moussaid
Abstract The effects of waxing, irradiation doses and storage on phenolic compounds and colour of irradiated oranges were investigated. Mature oranges (Citrus sinensis (L) Osbeck var Maroc late) waxed or unwaxed were treated with 0, 1 or 2 kGy radiation and stored up to 9 weeks at 20 °C and 40,50% RH. Colour of the oranges, total phenols and flavones in the peel were measured. Phenolic compounds increased with irradiation dose and storage time. Hue angle, L* value and chroma of the orange colour were more affected by waxing and storage time than the irradiation treatment. Changes in the phenolic compounds were linked with changes in the redness and saturation of the orange colour. Irradiation stimulated synthesis of flavones; waxing controlled changes induced by irradiation. These results may aid in maintaining the quality and safety of oranges during storage. Copyright © 2004 Society of Chemical Industry [source]


Wheat dough rheology and bread quality effected by Lactobacillus brevis preferment, dry sourdough and lactic acid addition

INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 7 2010
Daliborka Koceva Komleni
Summary The influence of chemical and biological acidification on dough rheological properties and bread quality has been investigated. Two different flour types were used. Dough was chemically acidified with lactic acid. Two types of biologically acidified dough were prepared: dough with dry sourdough and with a Lactobacillus brevis preferment. Wheat dough rheological properties were investigated using the Farinograph, Extensograph and Amylograph. The baking response was also determined using standard baking tests. Addition of acidifiers resulted in firmer doughs with less stability, decreased extensibility and decreased gelatinisation maximum. The biological acidifiers increased the bread specific volume. Lactic acid addition had no influence on bread specific volume. In general, biological and chemical acidification decreased bread hardness. The addition of dry sourdough significantly decreased the lightness and increased the yellowness and redness of the bread crumb. The crust chroma, hue angle and brownness index were significantly changed by addition of acidifiers. [source]


Palynological, physico-chemical and colour characterization of Moroccan honeys: I. River red gum (Eucalyptus camaldulensis Dehnh) honey

INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 4 2003
Anass Terrab
Summary The melissopalynological, physico-chemical and colour characteristics of Eucalyptus honeys from Morocco were studied. It is generally accepted that a minimum content of 70% of Eucalyptus pollen is necessary to classify an Eucalyptus honey as unifloral. Twenty-eight physico-chemical and five colour parameters were measured, including the content of sugars and minerals, proline, water content, pH, acidity, hydroxymethylfurfural, diastase activity, ash, electrical conductivity, colour coordinates (L*, a*, b*), chroma (C*ab) and hue angle (hab). Pollen analysis was included, and samples contained a mean of six pollen types (range 2,12). The majority of the samples (75%) contained more than 90%Eucalyptus pollen. The presence of Quercus, Plantago and Thymelaea pollen allows the differentiation of these honeys from those with a different geographical origin. Physico-chemical analysis showed that there was a low percentage of sucrose ( = 0.01%) and trisaccharides. Mineral analysis showed a low percentage of Mg ( = 25.99 ppm) and K ( = 205 ppm), while electrical conductivity ( = 721 ,S cm,1) and diastase activity ( = 39.05 °Gothe) showed medium-high values. The colour parameters lightness (L*) and chroma (C*ab) showed relatively low values. [source]


EFFECT OF POLYGODIAL ON MECHANICAL, OPTICAL AND BARRIER PROPERTIES OF CHITOSAN FILMS

JOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 2 2010
L. MORENO-OSORIO
ABSTRACT The mechanical, optical and barrier properties of chitosan films containing polygodial (0.0, 2.7, 13.9, 25.0 mg/g of chitosan) were studied. Water vapor permeability (WVP), tensile strength, percentage elongation at break, CIELab color parameters, hue angle and chroma of films were determined. Fourier transform infrared (FTIR) was also performed to determine functional group interaction between the matrix and polygodial added. The use of polygodial resulted in stronger films without losing their extensibility and with low WVP. Films became darker with yellow-green coloration with increasing polygodial concentration. Polygodial added to chitosan films did not have any interaction with the amino groups of chitosan as measured by FTIR. Polygodial as a natural dialdehyde can effectively be applied to enhance some physical properties of edible films prepared with chitosan. PRACTICAL APPLICATIONS There has been an increased interest in the study of edible,biodegradable packaging films during the last decade, offering an alternative and partial solution to the problem of accumulation of solid waste composed of synthetic inert polymers, and chitosan films has been studied with this purpose. Furthermore, replacing synthetic additives by natural compounds such us polygodial can be a suitable manner to improve some physical properties of those chitosan films. [source]


QUALITY LOSS DURING TOMATO PASTE PRODUCTION VERSUS SAUCE STORAGE

JOURNAL OF FOOD PROCESSING AND PRESERVATION, Issue 4 2001
RADHIKA K. APAIAH
Two studies were conducted to assess the extent of quality changes in tomato processing versus storage. For the processing study, tomato juice was vacuum concentrated into paste at 68C for 300 min (LT) or 85C for 34 min (ST) and samples taken at 5,26 Brix. Reduced ascorbic acid (RAA) degraded sooner during LT than ST, but reached equivalent final concentrations. The particle size decreased and hue angle increased during LT, but not ST. The viscosity decreased more during LT than ST. There was no formation of 5-hydroxymethyl furfural (HMF.) For the storage study, commercial tomato sauce was stored at 4 to 55C for 6 months. RAA degradation and HMF formation during storage were first order with activation energies of 77 and 70 KJ/mole, respectively. The particle size decreased at all storage temperatures, viscosity decreased at 45 to 55C and hue angle increased at 37 to 55C. In general, quality loss of tomato sauce during processing was greater than during storage. [source]


EFFECTS OF ANTIOXIDANTS ON IRRADIATED BEEF COLOR

JOURNAL OF FOOD QUALITY, Issue 3 2010
LAKSHMANAN RAMAMOORTHI
ABSTRACT Fresh beef was dipped into ascorbic acid (AA; 500 ppm), butylated hydroxyanisole (BHA, 150 ppm), butylated hydroxytoluene (BHT, 100 ppm) or propyl gallate (PG; 100 ppm); control samples were dipped in deionized water. Samples were vacuum packaged, then irradiated (0, 1.25 or 2.50 kGy). After irradiation, samples were stored (0, 7 or 14 days) at 4C. Color was assessed instrumentally (L*, a*, b*values, hue angles, chroma) and visually. All antioxidants increased L*value by two units (lighter); however, irradiation dose had no effect. Irradiation increased wet dog and rancid odors of beef; however, it decreased sour odor, a*value, chroma and hue angle, and increased visual green and brown colors, indicating that it reduced redness and color intensity. Antioxidants reduced L*(decreased lightening) and a*values (redness) compared to controls. BHA had the greatest effect on a*value. AA decreased visual green color the most; however, BHA and BHT were also effective. Antioxidants had inconsistent effects on b*value, chroma and hue angle. Storage decreased L*and a*values, and chroma. BHA and PG were most effective at maintaining low thiobarbituric acid-reactive substances when samples were irradiated. PRACTICAL APPLICATIONS Irradiation has the potential to reduce microbial load, increasing both the safety and shelf life of red meat products; however, it has the potential to damage fresh meat color, resulting in unacceptable discoloration. Irradiation can increase off-odors (wet dog, rancid) of beef; however, it can decrease sour odor, instrumental measures of red color, and increase visual green and brown colors. Use of antioxidants including ascorbic acid, butylated hydroxytoluene, butylated hydroxyanisole and propyl gallate can help maintain the color of irradiated beef held in refrigerated storage for up to 2 weeks. [source]


COMPARISON AMONG GLUTEN, MALTODEXTRIN, AND SOYBEAN OIL COATINGS AS FLAVOR CARRIERS ON PITA CHIPS,

JOURNAL OF FOOD QUALITY, Issue 5 2000
H.A. MANSOUBI
ABSTRACT Dietary health concerns of consumers have prompted manufacturers to produce snacks with lower fat content. Reduced fat products need additional ingredients to compensate for flavor loss. Gluten and maltodextrin coatings were compared with soybean oil as a carrier of cheese powder on pita chips. Coated pita chips were packaged with or without nitrogen and stored at 33C and 50% humidity for 60 days. Physical, chemical, microbiological, and sensory properties of the chips were evaluated. Saturation index and hue angle were significantly different at 30 and 60 days for all treatments. Instrumental texture analysis was inconclusive due to high standard deviations. Peroxide value for oil-coated chips increased significantly over time. Consumer acceptance testing indicated a stronger cheese flavor for maltodextrin and gluten treatments compared with oil. No off-flavors were detected from any chips. Microbial counts were low and did not differ significantly among treatments. Gluten and maltodextrin coatings may be alternative flavor carriers to oil for reduced fat content in snack foods. [source]


Inhibition of Browning on Fresh-cut Pear Wedges by Natural Compounds

JOURNAL OF FOOD SCIENCE, Issue 3 2006
Gemma Oms-Oliu
ABSTRACT: Mechanical operations such as peeling and cutting during minimal processing involve enzymatic browning of fruit tissue. The objective of this work was to evaluate the individual and combined effects of N-acetyl-L-cysteine, reduced glutathione, ascorbic acid, and 4-hexylresorcinol to control pear browning. Browning of fresh-cut pears was prevented by a minimum concentration of 0.75% N-acetyl-L-cysteine up to 28 d at 4°C. Reduced glutathione treatments were also effective along the storage time although browning was observed after 21 d of storage with a dip of 0.75% reduced glutathione. However, ascorbic acid or 4-hexylresorcinol treatments did not seem to completely prevent browning of pear wedges throughout the storage period. An enhanced antibrowning effect was observed when combining both N-acetyl-L-cysteine and reduced glutathione, considering hue angle as color change index. Thus, hue angle reached maximum levels at 1.5% N-acetyl-L-cysteine (NAC) or 1.5% glutathione (GSH) and 1% NAC with 1% GSH for 28 d. Besides, N-acetyl-L-cysteine, reduced glutathione and 4-hexylresorcinol completely inhibited polyphenol oxidase activity as well as browning inhibitors slightly reduced firmness of fresh-cut pears. [source]


Impact of Thermal Treatment on Color and Pigment Pattern of Red Beet (Beta vulgaris L.) Preparations

JOURNAL OF FOOD SCIENCE, Issue 6 2004
K.M. Herbach
ABSTRACT: The impact of heating at 85°C during 8 h on overall color and betalain pattern of red beet (Beta vulgaris L. ssp. vulgaris) juice was investigated. Although the hue angle of 358° in fresh juice was indicative of the typical red-purple appearance, heating for 8 h induced an unexpected shift to 62° resulting in a yellow-orange solution. To monitor the underlying structural alterations of betalains, a new high-performance liquid chromatography separation compatible with mass spectrometry was developed. Applying this method, 2 novel yellow neobetanin structures and 2 orange-red betanin degradation products were preliminarily identified, and neobetanin formation resulting from heat exposure was proven for the 1st time. These 5 compounds were held responsible for the orange shift of red beet juice during thermal treatment. The relevance of these findings for industrial beet processing was demonstrated by comparison of pigment patterns of heated red beet juice samples and a commercial concentrate. On the basis of these results, a scheme for the thermal degradation of betanin is proposed. [source]


Comparison of the Stability of Pelargonidin-based Anthocyanins in Strawberry Juice and Concentrate

JOURNAL OF FOOD SCIENCE, Issue 4 2002
G.A. Garzón
ABSTRACT Strawberries were processed into juice (8° Brix) and concentrate (65° Brix) and different lots were fortified with pelargonidin 3-glucoside, pelargonidin 3-sophoroside, and acylated pelargonidin 3-sophoroside 5-glucoside. Changes in pigment concentration, color (CIE L*a*b*) and ascorbic acid content were monitored during storage at 25 °C. Anthocyanin and ascorbic acid degradations followed 1st order reaction kinetics. Fortification increased the half-life of the pigments from 3.5 to 5 d in concentrate and from 5 to 12 d in juice. The half-life of ascorbic acid was 2 d in juice samples and ranged from 3 to 10 d in concentrate samples. Both systems showed changes in chroma and hue angle, but maintained L* values. [source]


Effect of cut-type on quality of minimally processed papaya

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 12 2008
A Carla SJ Argańosa
Abstract BACKGROUND: This research was undertaken to study the effects of different cut-types (cube, parallelepiped, cylinder and sphere) on the quality and shelf-life of papaya cv. Sunrise Solo. Physicochemical analyses were carried out during 10 days of storage at 4 °C to determine colour, firmness, pH, titratable acidity, total soluble solids, weight loss and vitamin C content. Microbiological analysis and sensory evaluation were also performed. RESULTS: Papaya spheres (1.55 cm radius) presented the most favourable physicochemical and microbiological properties (smaller changes in colour parameters L*, a*, b*, chroma and hue angle, firmer texture, lower increase in pH, higher titratable acidity, almost constant total soluble solids, reduced weight loss, high vitamin C content and lower microbial loads) and sensory characteristics on day 10, while papaya cubes (1.4 cm side) proved to be the least acceptable. CONCLUSION: The results of physicochemical, microbiological and sensory analyses performed on different cut-types of papaya indicated acceptable fresh-cut produce during 10 days of storage at 4 °C. The potential shelf-life at 4 °C is therefore 10 days, provided that no contamination occurs in the postharvest period and during minimal processing operations. Copyright © 2008 Society of Chemical Industry [source]


A colorimetric study of oenin copigmented by procyanidins

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 2 2007
Bénédicte Berké
Abstract A colorimetric method was used to analyse the influence of procyanidin structure on colour changes of malvidin 3- O -glucoside (oenin) solution resulting from copigmentation. The study was performed in hydroalcoholic citrate/phosphate buffer solution (120 g L,1) at pH 3.6 and ionic strength 0.2 mol L,1. Chromatic L*, a* and b* coordinates (CIELAB, D65/10° illuminant/observer condition) obtained from spectral curves recorded between 360 and 830 nm allowed the calculation of lightness L*, chroma C* and hue angle hab. In general, addition of copigment induced colour enhancement (loss of lightness and increased chroma). The prevailing parameters affecting colour changes were lightness and chroma for monomers and lightness and hue for procyanidins B5 and B8 (C4,C6 dimers). A small blueing effect was observed only for catechin monomer-copigmented solutions. For procyanidin copigments, as the structural complexity of the copigment increased, the hue angle moved to yellower values. The ester gallate of dimer B2 produced the strongest modification of colour attributes of oenin solution. Copyright © 2006 Society of Chemical Industry [source]


Seasonal climate effects on root colour and compounds of red radish

JOURNAL OF THE SCIENCE OF FOOD AND AGRICULTURE, Issue 11 2002
M Schreiner
Abstract ,Nevadar' radishes were grown throughout the year. Climate parameters (mean temperature, mean irradiation) and quality characteristics of radishes fulfilling consumer quality requirements, such as root colour, glucosinolates, monosaccharides and pectic substances, were determined. The quality characteristics strongly differed depending on the seasonal climate conditions. The seasonal dependence ranged from a slight climate influence (alkenyl glucosinolates r2,=,0.23), over a moderate climate effect (indolyl glucosinolates r2,=,0.40, glucose r2,=,0.50) up to a strongly distinctive climate influence (hue angle r2,=,0.77, chroma r2,=,0.72, fructose r2,=,0.81, pectic substances r2,=,0.99). Therefore, according to consumer-oriented quality production of radish, the temperature and irradiation influence should be taken into account in the production process. Recommendations for quality production of radish will be the selection of bright red cultivars marked by a high photosynthetic capacity (yield,>,0.80,mV) at relatively low mean irradiation intensities (50,100,µmol ,m2,s,1) and lower mean temperatures (11,13,°C). Thus sufficient photochemical energy can be provided for the synthesis of quality-determining compounds. For the production of bioactive radishes showing particularly relatively high contents of indolyl glucosinolates, cultivation should be carried out in spring and autumn. In summer cultivation, consumer preferences in taste can particularly be satisfied with the desired contents of alkenyl glucosinolates and monosaccharides. © 2002 Society of Chemical Industry [source]


Colorimetric study of SCOTDIC colour specifier

COLORATION TECHNOLOGY, Issue 5 2008
Asim Kumar Roy Choudhury
In this study, SCOTDIC cotton standard colours (a physical exemplification of the Munsell system) were studied extensively. L*, a*, b* values were measured and plotted to check the uniformity of the Munsell (SCOTDIC) hue, value and chroma values in a CIELAB diagram. Although for some borderline hues the hue angles were quite different than expected (around 0° or 360°), the correlation between SCOTDIC hue and CIELAB hue angle was fairly good and the correlation between SCOTDIC value and CIELAB lightness was also quite high. However, the correlation between SCOTDIC chroma and CIELAB chroma was only moderate. In the CIELAB diagram, the constant SCOTDIC hue and constant chroma loci took the shape of approximately linear radial lines starting from the origin and approximately concentric circles with the origin as their centres, respectively. However, some deviations were observed for high chroma colours and yellow hues in the respective cases. The instrumentally predicted Munsell notations were compared with the actual SCOTDIC notations. Some deviations of the SCOTDIC system from the Munsell system were observed. [source]


An evaluation of thermochromic prints based on microencapsulated liquid crystals using variable temperature colour measurement

COLORATION TECHNOLOGY, Issue 4 2005
Robert M Christie
A variable temperature colour measurement technique has been developed to characterise the temperature-dependent colour change, known as ,colour play', observed with thermochromic prints based on microencapsulated liquid crystals. The effect is most pronounced over a black background. The liquid crystals exhibiting the thermochromic effect adopt a chiral nematic phase with an underlying smectic A phase. A variety of methods for presenting and interpreting the data obtained, as the colour of the print passes through the spectrum, is explored. The effect of temperature on the wavelength of reflected light, a*bhue angle have been studied. The ,blue phase', exhibited transiently as the liquid crystal passes out of the chiral nematic phase to form an isotropic liquid, has been detected as an increase in lightness and a hue shift. Prints on nylon/lycra are found to have acceptable wash fastness, but show some sensitivity to light. [source]


The mapping of a surface of constant visual depth in CIELAB colour space,

COLORATION TECHNOLOGY, Issue 6 2002
Chao-Chi Chen
Independent visual assessments of depth by a panel of four professional colourists were made on dyeings prepared along eight hue directions in CIELAB colour space. From the assessments made, the variation of lightness with chroma for dyeings of uniform depth was mapped along the hue directions. An algorithm was developed to determine the lightness on the surface for any colour of given chroma and hue angle. Whilst direct comparison with the surface defined by the Christ formula for 1/1 standard depth was not possible, it was found that qualitatively the shapes of the two surfaces were very similar. The Christ formula defined greater increases in lightness with chroma in the yellow and lime-green regions than the surface obtained in this work, which may be due to an inconsistency of depth of the 1/1 standard depth samples in this region, as indicated by other depth formulae. [source]


Effect of king palm (Archontophoenix alexandrae) flour incorporation on physicochemical and textural characteristics of gluten-free cookies

INTERNATIONAL JOURNAL OF FOOD SCIENCE & TECHNOLOGY, Issue 3 2009
Karina N. De Simas
Summary The replacement of the blend of rice flour (70%) and corn starch (30%) with king palm flour [Archontophoenix alexandrae (F. Muell.) H. Wendl. and Drude] at levels of 0,30% was investigated for its effects on the chemical and physical characteristics of gluten-free dough and cookies. Cookies containing 10, 20 and 30% of king palm flour were analysed by twenty-one celiac consumers through preference-ranking test. Ash, minerals, and dietary fibre contents increased in cookies that were added with king palm flour. Compared with the control dough, the incorporation of king palm flour increased the firmness and decreased the adhesiveness of dough samples. The incorporation of king palm flour increased the hardness of cookies in relation to the control dough. None of the cookies differed significantly (P > 0.05) in the lightness (L*) parameter. All formulations produced cookies with hue angles around 60, which indicate a tendency to brown colour. The study reveals that the incorporation of king palm flour showed desirable results in nutritional characteristics, because of the increase of the dietary fibre and minerals contents. In this study, the cookies preferred by celiac consumers were those containing 10 and 20% of king palm flour (P > 0.05). [source]


EFFECTS OF ANTIOXIDANTS ON IRRADIATED BEEF COLOR

JOURNAL OF FOOD QUALITY, Issue 3 2010
LAKSHMANAN RAMAMOORTHI
ABSTRACT Fresh beef was dipped into ascorbic acid (AA; 500 ppm), butylated hydroxyanisole (BHA, 150 ppm), butylated hydroxytoluene (BHT, 100 ppm) or propyl gallate (PG; 100 ppm); control samples were dipped in deionized water. Samples were vacuum packaged, then irradiated (0, 1.25 or 2.50 kGy). After irradiation, samples were stored (0, 7 or 14 days) at 4C. Color was assessed instrumentally (L*, a*, b*values, hue angles, chroma) and visually. All antioxidants increased L*value by two units (lighter); however, irradiation dose had no effect. Irradiation increased wet dog and rancid odors of beef; however, it decreased sour odor, a*value, chroma and hue angle, and increased visual green and brown colors, indicating that it reduced redness and color intensity. Antioxidants reduced L*(decreased lightening) and a*values (redness) compared to controls. BHA had the greatest effect on a*value. AA decreased visual green color the most; however, BHA and BHT were also effective. Antioxidants had inconsistent effects on b*value, chroma and hue angle. Storage decreased L*and a*values, and chroma. BHA and PG were most effective at maintaining low thiobarbituric acid-reactive substances when samples were irradiated. PRACTICAL APPLICATIONS Irradiation has the potential to reduce microbial load, increasing both the safety and shelf life of red meat products; however, it has the potential to damage fresh meat color, resulting in unacceptable discoloration. Irradiation can increase off-odors (wet dog, rancid) of beef; however, it can decrease sour odor, instrumental measures of red color, and increase visual green and brown colors. Use of antioxidants including ascorbic acid, butylated hydroxytoluene, butylated hydroxyanisole and propyl gallate can help maintain the color of irradiated beef held in refrigerated storage for up to 2 weeks. [source]


Colorimetric study of SCOTDIC colour specifier

COLORATION TECHNOLOGY, Issue 5 2008
Asim Kumar Roy Choudhury
In this study, SCOTDIC cotton standard colours (a physical exemplification of the Munsell system) were studied extensively. L*, a*, b* values were measured and plotted to check the uniformity of the Munsell (SCOTDIC) hue, value and chroma values in a CIELAB diagram. Although for some borderline hues the hue angles were quite different than expected (around 0° or 360°), the correlation between SCOTDIC hue and CIELAB hue angle was fairly good and the correlation between SCOTDIC value and CIELAB lightness was also quite high. However, the correlation between SCOTDIC chroma and CIELAB chroma was only moderate. In the CIELAB diagram, the constant SCOTDIC hue and constant chroma loci took the shape of approximately linear radial lines starting from the origin and approximately concentric circles with the origin as their centres, respectively. However, some deviations were observed for high chroma colours and yellow hues in the respective cases. The instrumentally predicted Munsell notations were compared with the actual SCOTDIC notations. Some deviations of the SCOTDIC system from the Munsell system were observed. [source]