Food & Beverages

Description

The Food Industry has a long history of measuring the colour of their products. The reasons for doing this are as many and varied as the industry itself but the main criterion is standardisation.

Controlling the colour of materials enables the food producer to reject any that is substandard before offloading, during processing and prior to shipment. This guarantees that the final colour satisfies the consumer’s expectations.

Please do not hesitate to contact us to discuss your specific application.

Scales & Values

Grading techniques are widely used to assess product colour by comparison with a representative series of fixed colour standards.

For many product types, a characteristic set of standards was agreed and adopted to aid colour control and the communication of colour specifications; the result is s selection of traditional colour grading scales that have been adopted as industry standards and are still common today.

Your colour scale determines your instrument choice. We would be delighted to offer advice as to the correct colour scale and thus instrument choice for your application. Please do not hesitate to contact us.

Colour Scales:

  • Alpha Amylase Activity in Lquid Egg
    • When liquid whole egg is pasteurised, the efficiency of the pasteurisation can be checked by measuring the reduction in the alpa-amylase activity
    • Instruments required: Lovibond® Comparator; Daylight unit; Alpha Amylase disc 4/29; 25 mm optical glass
  • Alpha Amylase in Malt
    • The American Society of Brewing Chemists’ ( ASBC) procedure for determining alpha-amalyse in malt uses dextrinization. In the presence of beta- amylase, alpha-amylase converts soluble starch to the sugar maltose.
    • Instruments required: Lovibond® Comparator. Alpha Amylase disc 4/29, 2 x 13.5mm Cells
  • AOCS-Tintometer® Colour
    • Colour scale used as a standard by the USA oil and fats refineries, rendering plants and companies trading or associated with the American edible oils and fats industry.
    • It is a modified red and yellow version of the Lovibond® RYBN Colour scale used for fats, oils and derivatives.
    • The AOCS-Tintometer® Colour Scale is a special red and yellow version of the Lovibond® RYBN scale using the AOCS-Tintometer Red Scale.
    • Please note: It uses the AOCS-Tintometer® Red scale, which is not the same as the Lovibond® standard Red scale.
    • Instruments that can be used: AF710-3; PFX880/AT – Heated; PFX 950 / 995 / i /Heated; PFX / i-195 / 4 or PFX / i-195 / 7
  • beta Carotene (BS 684 Section 2.20)
    • Beta Carotene is a strongly-coloured red-orange pigment abundant in plants and fruits. (e.g. beta Carotene is the substance in carrots that colours them orange.)
    • This scale is a direct measurement of beta carotene content of vegetable oils in ppm (part per million.)
    • Instruments that can be used: PFX 950 / 995 / i / Heated
  • Chlorophyll A & B (AOCS Cc 13d)
    • Chlorophyll is a green pigment found in almost all plants. It is vital for photosynthesis, which allows plants to obtain energy from light.
    • It is a poor absorber of green and near-green portions of the spectrum, hence the green color of chlorophyll-containing tissues.
    • This scales enables a direct measurement of chlorophyll A & B content of oils in ppm (parts per million.)
    • Instruments that can be used: PFX 950 / 995 / i / Heated
  • CIE 94
    • In 1994 the CIE released a new tolerance method called CIE94. Like CMC, the CIE94 tolerancing method also produces an ellipsoid. The user has control of the lightness (kL) to chroma (KC) ratio, as well as the commercial factor (cf). These settings affect the size and shape of the ellipsoid in a manner similar to how the l:c and cf settings affect CMC.
    • However, while CMC is targeted for use in the textile industry, CIE94 is targeted for use in the paint and coatings industry. You should consider the type of surface being measured when choosing between these two tolerances. If the surface is textured or irregular, CMC may be the best fit. If the surface is smooth and regular CIE94 may be the best choice.
    • Instruments that can be used: RT range / OnColor range
  • CIE L*u*v* Colour Space
    • Uniform colour space adopted in 1976. Appropriate for use in additive mixing of light. (eg., Colour Television)
    • Instruments that can be used: RT range / OnColor range; NC45
  • CIE L*a*b*
    • A Colour space in which values L*, a* and b* are plotted using a Cartesian coordinate system. Equal distances in the space approximately represent equal colour differences. L* represents lightness; a* represents the red/green axis; and b* represents the yellow/blue axis. CIE L*a*b* is a popular colour space for measuring both reflective and transmissive samples.
    • Instruments that can be used: most instruments in the Lovibond® range
  • CIELAB (L*C*h)
    • This is an assessment of colour system that is more usually used to set tolerances once the hue, chroma and lightness limits are established.
    • While CIELAB (L*a*b*) uses Cartesian coordinates to calculate a colour in a colour space, CIELAB (L*C*h) uses polar coordinates. This colour expression can be derived from CIELAB (L*a*b*). The L*, as before defines lightness, C* specifies chroma and denotes hue angle, an angular measurement.
    • The L*C*h expression offers an advantage over L*a*b* in that it is very easy to relate to the earlier systems based on physical samples, like the Munsell Colour Scale.
    • Instruments that can be used: most instruments in the Lovibond® colour range
  • CMC Tolerancing
    • CMC is not a colour space but rather a tolerancing system.
    • CMC tolerancing is based on CIELAB (L*C*h) and provides better agreement between visual assessment and measured colour difference. CMC tolerancing was developed by the Colour Measurement Committee of the Society of Dyers and Colourists in Great Britain and became public domain in 1988.
    • Instruments that can be used: RT range / OnColor range; NC45
  • Delta E* colour difference
    • Assessment of colour is more than a numeric expression. Usually it’s an assessment of the colour difference (delta) from a known standard. CIELAB (L*a*b*) and CIELAB (L*C*h) are used to compare the colours of two objects.
    • The expressions for these colour differences are DL*, Da*, Db*, or DL* DC* DH* (“D” symbolises “delta,” which indicates difference). Note: DH* is usually used instead of Dh to enable DE* to be calculated.
  • Honey Colour (Pfund Equivalents)
    • For grading commercial honeys, ranging from pale through to deep amber and based on Pfund values in millimetres. The US Department of Agriculture (USDA) has established its own descriptive colour classification for extracted honey, which is based on Pfund values.
    • When using the Lovibond Comparator range of honey discs, the W680 10mm/OG cell must be used. The exception to this is the USDA disc where the W60/33mm/OG cell must be used.
    • Instruments that can be used: PFX-195/7 / i / Honey Colorpod (pfund equivalents)
  • Hunter Lab
    • A uniform color scale devised by Hunter in 1958 for use in a color difference meter. It is based on Hering’s opponent-colors theory of vision.
    • Instruments that can be used: RT range / OnColor range; NC45
  • International Fruit Juice Union (IFU) Colour
    • Developed in Europe for grading the colour of fruit juices and concentrates with a yellow/amber colour such as apple, pear and white grape. Colour values range from 1 to 25 as follows: Discs 4/48 range 1-9 IFU, 4/49 9-17 IFU and 4/50 17-25 IFU.
    • Instruments required: AF331 IFU Colour Scale
  • Lovibond® RYBN Colour
    • The Lovibond® Scale is based on 84 calibrated glass colour standards of different densities of magenta (red), yellow, blue and neutral, graduating from desaturated to fully saturated. Sample colours are matched by a suitable combination of the three primary colours together with neutral filters, resulting in a set of Lovibond® RYBN units that define the colour.
    • Since several million combinations are available, it is possible to match the colour of almost any sample; it is particularly popular for measuring the colour of oils and fats, chemicals, pharmaceuticals and syrups.
    • Instruments that can be used: PFX range
  • Maple Syrup
    • Colour scales for grading Maple Syrup
    • Instruments required: Lovibond® Comparator; daylight unit, disc/s 299520 / 299370 / 288180, 10 mm / 33 mm fused optical cell
  • Milk Quality Resazurin Test
    • The Resazurin test is designed for assessing the quality of raw bulked milk.
    • This is essentually a rapid bacteria estimation and can be carried out either as a 10 minute pass or fail, a 3 hour triple reading test or as the standard and generally accepted 1 hour test.
    • Resazurin gives milk a characteristic blue colour and the test is based on the ability of bacteria in the milk to reduce the blue dye. The quality of the milk is judged by noting the degree of colour change – from blue through mauve and purple and pink and finally colourless – after a stated period of incubation, or the time required to reduce the dye to a predetermined colour.
    • Instruments required: AF706 Resazurin Test Kit
  • Optical density (Absorbance)
    • Please note; with both our PFX and PFXi ranges Absorbance is referred to as Optical Density (OD). This is an available Colour Scale.
    • Absorbance should not be confused with Absorptance (the fraction of light absorbed by a sample.)
    • Instruments that can be used: PFX range
  • Spectral data
    • Spectral data, where colour measurement is concerned, is the data derived from measuring the level of reflectance or transmittance of a given colour at selected wavelengths throughout the visible spectrum.
    • Instruments that can be used: PFX and RT range
  • Transmittance
    • The ratio of transmitted flux to incident flux under specified conditions
    • Instruments that can be used: PFX range
  • Whiteness Index (ASTM E 313)
    • Certain industries such as paint, textiles and paper manufacturing, evaluate their materials and products based on standards of whiteness. Typically, this whiteness index is a preference rating for how white a material should appear
    • The Whiteness Index is a measure which correlates the visual ratings of whiteness for certain white and near-white surfaces
    • The American Standards Test Methods (ASTM) has defined whiteness and yellowness indices. The E313 whitness index is used for measuring near-white, opaque materials such as paper, paint and plastic. In fact, this index can be used for any material whose colour appears white.
    • Instruments that can be used: RT range / OnColor range; NC45
  • xyY chromacity co-ordinates
    • The coordinates x, y, and z are derived from the XYZ Tristimulus values by the following calculation such that x + y + z = 1, x = X/(X + Y + Z), y = Y/(X + Y + Z), z = Z/(X + Y + Z)
    • The values of x and y can then be used to pinpoint a colour in the x y coordinate system. The x and y chromaticity coordinates are generally reported along with the value of luminance factor Y
    • Instruments that can be used: most instruments in the Lovibond® colour range
  • XYZ tristimulus values
    • The CIE XYZ 1931 Tristimulus system is a modified version of the RGB colour tristimulus system and uses non real or imaginary stimuli. This innovation allows all colours within its gamut to be expressed as positive numbers, unlike the RGB system, where some colours fall outside its gamut and are expressed as negatives. The XYZ chromaticity co-ordinates are defined as x,y,and z
    • Instruments that can be used: most instruments in the Lovibond® colour range
  • Yellowness Index (ASTM E 313)
    • Yellowness Index is a number calculated from spectrophotometric data that describes the change in colour of a test sample from colourless through to yellow
    • The American Standards Test Methods (ASTM) has defined whiteness and yellowness indices. The ASTM’s E313 yellowness index is used to determine the degree to which a sample’s colour shifts away from an ideal white. The D1925 yellowness index is used for measuring plastics
  • Whisky
    • A Series of colour standards for grading the colour of Whisky based on the Lovibond® Series 52 Brown Scale
  • ICUMSA Colour Index
    • Photometric methods for colour grading of filtered sugar solutions based on the transmittance of the solution at a known concentration (Brix value) and at the specified wavelength of 420 nm for white sugars and other light coloured products or 560 nm for darker coloured products.
    • Instruments that can be used: PFX-195/ 7 / i / 880-S
 

Please send us an email explaining what you would like to test, your colour application and environment and we will send you a brochure with specifications based on your requirements.

p>Please send us an email explaining what you would like to test, your colour application and environment and we will recommend a suitable Lovibond® Tintometer colour testing instrument.

Additional information

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