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Colorimetry of dairy products
Abstract
Reflectance colorimetry was investigated to measure the colour of whole (WMP) and skim milk (SKMP) powders, infant formulas (IF), an adult nutritional product (ANP), unsalted (USB) and salted (SB) butters. The colorimeter gave precise results and was cost effective, illustrating the benefits of the adoption of a colorimeter rather than the current practice of using reference charts and powders. New Zealand dairy products are yellower compared with other dairy products because of their relatively high naturally occurring β-carotene content.
... 18 Compared with other detection methods, colorimetric method has many advantages, such as low cost, simplicity, and portability. 19 The sample can be solid or opaque liquid, which is not affected by reference materials that may change over time. This method also plays an important role in the detection of some special samples (such as harmful byproducts generated in industrial production processes). ...
A colorimetric sensor detects an analyte by utilizing the optical properties of the sensor unit, such as absorption or reflection, to generate a structural color that serves as the output signal to detect an analyte. Detecting the refractive index of an analyte by recording the color change of the sensor structure on its surface has several advantages, including simple operation, low cost, suitability for onsite analysis, and real-time detection. Colorimetric sensors have drawn much attention owing to their rapidity, simplicity, high sensitivity and selectivity. This Review discusses the use of colorimetric sensors in the food industry, including their applications for detecting food contaminants. The Review also provides insight into the scope of future research in this area.
... So far, the consumption of dairy products is increasing year by year, especially infant formula milk powder. It is the most important source of nutrition for non-breastfeeding infants (Ponnal et al., 2021), and has become a product with a rapid growth rate in Chinese dairy consumption. Potassium iodide is a kind of colorless and transparent granular powder, and it is easy to deliquesce in wet air and soluble in water. ...
... In this sense, colorimetry is a consistent and objective technique, widely used in the quality control of products containing natural pigments, which evaluates color using the parameters L* (luminosity) and a* and b* (red to green and yellow to blue, respectively) (Gordillo et al. 2015). Furthermore, it has a number of advantages over other methodologies, such as performing with uniform light, it is portable and inexpensive, samples can be solid or an opaque liquid, and it does not depend on the storage of references that can vary with time (Ponnal et al. 2021). ...
The prediction of such bioactive compounds using colorimetry is a promising, nondestructive, low-cost, and rapid alternative; however, the mathematical models are affected by the compounds present in the food, depending also on the methodology used for the analysis. In this sense, this work aimed to evaluate which compounds present in red fruits can affect the prediction of total phenolics and antioxidant capacity, using colorimetric parameters. The quantities of substances with potential impact previously found in these fruits were studied using the Plackett-Burman design. The results showed that anthocyanins, ascorbic acid, and tartaric acid influenced the colorimetric parameters, thus making these compounds impact the achievement of the equations. For the quantification of total phenolics, ascorbic acid was the only compound with a significant effect and also had an impact on the other methodologies of antioxidant capacity. The variations caused by ascorbic acid in the absorption coefficient and refractive index were also evaluated and it was concluded that the interference of this compound occurs by interactions with anthocyanins.
In the present study, fresh raw camel and cow's milk were concentrated to 20-30% total solids, and then freeze-dried under the temperature of (-50 °C to-75 °C), under vacuum. The physicochemical characteristics of the various freeze-dried powders were determined. The water activity (aw) of freeze-dried camel milk (FDC) and freeze-dried cow milk (FDW) ranged 0.253-0.307 and 0.148-0.301, respectively. While aw of the commercial milk sample (CMD) was 0.326. Both FDC and FDW had reasonable flowability as indicated by measuring their hausner ratio which ranged between 1.15 and 1.24. FDC had higher insolubility index (0.65-0.85) when compared with those of FDW(0.25-.055). The yield and hygroscobisity of freeze-dried samples ranged between (81.42-94.57) and 22.12-27.32, respectively. The measurements for colour characteristics indicated that the lightness ranged between 91.20 and 94.34 while the commercial sample had a value of 94.45. All samples had acceptable lightness, yellowness and redness when compared with those of the commercial sample. Small variation were determined in some of the chemical components of the various samples of FDC, FDC and CMD. It is recommended in the present investigation that freeze-drying of milk could be an extremely effective method for producing dried powder from camel and cow's milk with little changes in most nutrient compounds.
In the present study, fresh raw camel and cow's milk were concentrated to 20-30% total solids, and then dried using a pilot spray-dryer. The effect of direction of feed on physicochemical properties camel milk powders on physicochemical characteristics of the various spray-dried milks were determined. Some of the examined parameters of spray dried milks were affected, such as the water activity which had low values (0.154 - 0.208). Moreover, the degree of lightness was affected by direction of feeding, where co-current feeding gave the highest degree of lightness (97.73), when compared to counter current (93.82). The spray-drying samples also affected the solubility which recorded higher values of tested milk powder samples. The flowability was affected by the direction of feeding; the co-current feeding gave high values, when compared to counter-current feeding which gave less values (1.21-1.37). The yield was also affected, the spray-dried samples gave (68.84-88.20). The chemical analysis indicated that moisture, protein, fat, ash and acidity ranged 1.01-2.41%, 23.75-26.64%, 27.86-29.82% and 0.1-029%, respectively. The results show the importance of optimizing the drying process, in order to obtain products with better functional and physicochemical properti
Color. Dufossé L., Galaup P.. In : “Handbook of Dairy Foods Analysis”, Part 4: Sensory quality, 1st edition, Nollet L.M.L. and Toldrá F. (Eds.), Francis & Taylor, CRC Press, Boca Raton, Florida, USA, ISBN 9781420046311, 585-605, 2010.
CONTENTS
27.1 Introduction ........................................................................................................ 586
27.2 Description of the Techniques in Use in Dairy Food Color Analysis .................. 587
27.2.1 Color Determination Using Traditional Laboratory Visible
Spectrophotometers ............................................................................... 587
27.2.2 Visible and Near-Infrared Refl ectance (VNIR) Spectrophotometry ...... 587
27.2.3 Tristimulus Colorimetry ........................................................................ 588
27.2.4 Spectrophotometers Dedicated to Color Analysis .................................. 588
27.2.5 Color Chart or Color Fan ...................................................................... 589
27.2.6 Computer Vision, Digital Scanning, and Image Analysis ...................... 589
27.2.7 High-Performance Liquid Chromatography (HPLC) of Pigments ........ 589
27.3 Practical Applications in Dairy Foods Analysis ................................................... 590
27.3.1 Anteprocessing (i.e., Milk Production Related
to Cattle/Cow Feeding) ......................................................................... 590
27.3.2 Processing ...............................................................................................592
27.3.2.1 Butter .....................................................................................592
27.3.2.2 Cheese-Making Process .........................................................593
27.3.2.3 Use of Technologies Such as High-Pressure
Processing or Ultrafi ltration ...................................................593
27.3.2.4 Modifi cation of Dairy Food Composition (Substitution of
Milk Powder by Whey Powder or Soy Proteins, Use of Fat
Replacers, Addition of Chitosan or Orange’ Fibers …) ..........594
27.3.2.5 Studies about the Whiteness of Mozzarella or Browning of
the Same Cheese When Used in Pizza ...................................595
27.3.2.6 Role of the Microfl ora in the Development of Color at the
Surface of Soft Cheeses ..............................................................595
27.4 Postprocessing ......................................................................................................598
27.5 Quality Control ....................................................................................................599
27.6 Conclusion .......................................................................................................... 602
References ...................................................................................................................... 603
In the present work, the changes of color in whole milk powder (WMP) were evaluated in relation to the milking season and the thermal treatment applied to the milk before dry step. The WMP obtained under indirect thermal treatment conditions (IHT: 90-93 °C; 180 s) showed significant lower values of L*, reflectance measured at 450 nm and index of protein than WMP elaborated with direct thermal treatment (DHT: 105 °C; 30 s) (p<0.05). An opposite behavior showed the component b* and hidroximetilfurfural. WMP produced in summer revealed the lowest levels of L* in contrast with WMP from autumn and winter (p<0.05). In general, The WMP elaborated in spring and summer showed higher levels of b* for both thermal treatments.
The effect of high oryzanol rice bran oil (RBO) on the oxidative stability of low-heat and high-heat whole milk powder (WMP) was investigated. Milk (3.6% fat) was fortified with RBO at 0.1 and 0.2% (wt/wt) and was concentrated and dried. Control WMP was made without RBO addition. Thiobarbituric acid reactive substances (TBARS) were used to monitor oxidation during storage at 45 degrees C for 40 d. The oxidation of low-heat WMP was significantly reduced by addition of 0.1% RBO, but there was no significant effect on the oxidation of high-heat WMP. An increase of RBO to 0.2% did not significantly improve the oxidative stability when compared with 0.1% RBO. The TBARS in RBO-fortified, low-heat WMP increased with storage time up to 30 d but decreased with further storage to 40 d. The TBARS in all high-heat WMP and low-heat control WMP increased up to 20 d storage and then decreased with further storage. The most likely reason for this increase was due to the reaction of TBARS with milk proteins. Addition of RBO reduced the L (lightness) value and increased the b (yellowness) value but had no effect on the a (redness) value. When compared with the control milk powder, consumers could not detect any effect on the flavor of the reconstituted 0.1% RBO WMP but could detect a flavor difference in the 0.2% RBO WMP.
The lack of updated knowledge about the physical properties of milk powders aimed us to evaluate selected physical properties (water activity, particle size, density, flowability, solubility and colour) of eleven skim and whole milk powders produced in Europe. These physical properties are crucial both for the management of milk powder during the final steps of the drying process, and for their use as food ingredients. In general, except for the values of water activity, the physical properties of skim and whole milk powders are very different. Particle sizes of the spray-dried skim milk powders, measured as volume and surface mean diameter were significantly lower than that of the whole milk powders, while the roller dried sample showed the largest particle size. For all the samples the size distribution was quite narrow, with a span value less than 2. The loose density of skim milk powders was significantly higher than whole milk powders (541.36 vs 449.75 kg/m³). Flowability, measured by Hausner ratio and Carr’s index indicators, ranged from passable to poor when evaluated according to pharmaceutical criteria. The insolubility index of the spray-dried skim and whole milk powders, measured as weight of the sediment (from 0.5 to 34.8 mg), allowed a good discrimination of the samples. Colour analysis underlined the relevant contribution of fat content and particle size, resulted in higher lightness (L*) for skim milk powder than whole milk powder, which, on the other hand, showed higher yellowness (b*) and lower greenness (−a*). In conclusion a detailed knowledge of functional properties of milk powders may allow the dairy to tailor the products to the user and help the food processor to perform a targeted choice according to the intended use.
Color measurements of muscle-based and dairy foods. Dufossé L., Fernández-López J., Galaup P., Pérez-Alvarez J.A.. In : “Handbook of Food Analysis”, 3rd edition, two volume set, 1568 pages, Nollet L.M.L. and Toldrá F. (Eds.), Francis & Taylor, CRC Press, Boca Raton, Florida, USA, ISBN 978-1-466556546, volume 1, section I. Physical and sensory techniques, Chapter 1, 3-19, 2015.
Contents
1.1 Color on Muscle-Based Foods..........................................................................3
1.1.1 General Aspects of Color................................................................................3
1.1.1.1 Color Attributes..............................................................................................4
1.1.2 Color Measurement..........................................................................................5
1.1.2.1 Objective Methods.........................................................................................5
1.2 Color of Dairy Foods............................................................................................7
1.2.1 Description of the Techniques in Use in Dairy Food Color Analysis.............7
1.2.1.1 Color Determination Using Traditional Laboratory Visible Spectrophotometers......7
1.2.1.2 Visible and Near-Infrared Reflectance Spectrophotometry............................8
1.2.1.3 Tristimulus Colorimetry..........................................................................................8
1.2.1.4 Spectrophotometers Dedicated to Color Analysis............................................8
1.2.1.5 Color Chart or Color Fan.......................................................................................8
1.2.1.6 Computer Vision, Digital Scanning, and Image Analysis................................8
1.2.1.7 High-Performance Liquid Chromatography of Pigments................................9
1.2.2 Practical Applications in Dairy Foods Analysis....................................................9
1.2.2.1 Anteprocessing (i.e., Milk Production Related to Cattle/Cow Feeding)........9
1.2.2.2 Processing...............................................................................................................10
1.2.3 Postprocessing...........................................................................................................13
1.2.4 Quality Control............................................................................................................13
References............................................................................................................................15
A wide variety of colors leap into our eyes when we just look
around. We are surrounded by an infinite variety of colors in
our daily lives. An average person can distinguish as many as
350,000 different colors, among which are 5000 distinguishable
white colors, but the number of basic color terms is confined to
not more than 11 basic expressions, regardless of cultures or languages.
However, unlike length or weight, there is no physical
scale for measuring color, making it unlikely that everyone
will answer in the same way when asked what a certain color
is. For example, if we say “yellow butter” or “yellow cheddar”
to people, each individual will imagine different yellow colors,
because their color sensitivity and past experiences are bound to
be different. This is the problem with color. (continued)
Carotenoids are involved in the nutritional and sensory characteristics of dairy products, and are potential biomarkers for traceability of cows' feeding management. We review general and recent knowledge on carotenoids from forage to milk and dairy products in ruminants. Nearly 10 carotenoids (i.e., xanthophylls and carotene) have been quantified in forages, and their concentrations vary highly according to development stage and length of conservation. Sensitivity of -carotene to ruminal degra-dation varies among studies, depending on its dietary source. Data suggest that carotenoid digestion would be linked to dietary lipids for transit, and to specific transporters of lipophilic molecules for absorption. Among ruminants, only bovines accumulate high concentrations of carotenoids, mainly -carotene, possibly due to lower Vitamin A synthesis efficiencies in enterocytes. Carotenoid flows in plasma and tissues in dairy cows remain to be investigated, especially the ability of adipose tissue to release -carotene in depleted or underfed animals. Carotenoids in cows' milk mainly consist of all-trans--carotene and, to a lesser extent, lutein. In milk, concentration is more variable for -carotene than for retinol, for which the plasma concentration is well regulated. Milk concentration of -carotene depends on its dietary supply. Both animal and feeding factors that affect milk yield (i.e., breed, parity, physiological stage, level of intake) generally also control milk -carotene concentration by concentration/dilution mechanisms, and by efficiency of extraction from plasma. The -carotene concentration in cheese is highly linked to milk concentration, whereas high losses of retinol occur during cheese-making. The color of dairy products highly depends on their carotenoid concentration, 419 suggesting that color may be a promising rapid measurement tool for traceability of feeding condi-tions. Feeding management of dairy cows allows efficient control of carotenoid concentration and color in dairy products.
Exposing spray-dried whole milk powder to high shear and elevated temperature in a twin-screw continuous mixer increased the free fat content. The effects of operating conditions (powder feed rate, processor screw speed, and process temperature) on lactose crystallinity, particle size distribution, color, and moisture content of spray-dried whole milk powder were investigated using response surface methodology. Exposure to elevated temperatures and high shear: (a) increased the free fat to more than 80%, (b) crystallized the lactose, (c) reduced the average volume-based particle size, and (d) broadened the particle size distribution. The raw whole milk powder with creamy-white color turned into an oily paste with bright-yellow color. Processing enhanced the functional properties of spray-dried whole milk powder for milk chocolate manufacture.
Colour is an important quality attribute in the food and bioprocess industries, and it influences consumer’s choice and preferences. Food colour is governed by the chemical, biochemical, microbial and physical changes which occur during growth, maturation, postharvest handling and processing. Colour measurement of food products has been used as an indirect measure of other quality attributes such as flavour and contents of pigments because it is simpler, faster and correlates well with other physicochemical properties. This review discusses the techniques and procedures for the measurement and analysis of colour in food and other biomaterial materials. It focuses on the instrumental (objective) and visual (subjective) measurements for quantifying colour attributes and highlights the range of primary and derived objective colour indices used to characterise the maturity and quality of a wide range of food products and beverages. Different approaches applied to model food colour are described, including reaction mechanisms, response surface methodology and others based on probabilistic and non-isothermal kinetics. Colour is one of the most widely measured product quality attributes in postharvest handling and in the food processing research and industry. Apart from differences in instrumentation, colour measurements are often reported based on different colour indices even for the same product, making it difficult to compare results in the literature. There is a need for standardisation to improve the traceability and transferability of measurements. The correlation between colour and other sensory quality attributes is well established, but future prospects exist in the application of objective non-destructive colour measurement in predictive modelling of the nutritional quality of fresh and processed food products.
A tristimulus relectance technique was applied to the objective assessment of the colour of milk and dairy products. A variety of milk and dairy products (liquid milk, cultured products, cheese, butter, milk powder) was characterized based on the L* a*, b* (CIE-LAB) colour parameters. The b* value was not suitable for estimating the β-carotene content of butter, whereas storage defects (non-enzymatic browning reactions) of whey powder could be monitored using this parameter. La technique de réflexion tristimulus a été appliquée à la mesure objective de la couleur d'un certain nombre de laits et de produits laitiers du commerce. Parmi ceux-ci, on trouve des liquides, des produits fermentés frais tels que yaourts, diverses sortes de fromages, des beurres d'été et d'hiver et des poudres de lait, caractérisés par leurs valeurs L *, a * et b * selon la CIE. La composante jaune b * s'est révélée inadéquate à estimer la teneur en β-carotène du beurre, mais permet de suivre les altérations subies par une poudre de lactosérum en cours de stockage (brunissement non enzymatique).
Free and total fluorescent compounds, browning index, and color formation were measured in milk-based powdered infant formulas (IF) during 2 years of storage at 20 and 37 degrees C. The excitation spectra from 415 nm emission show three peaks (ex lambda1 = 270 nm, lambda2 = 325/315 nm, lambda3 = 350 nm) and from 347 nm excitation two emission peaks (415 and 520 nm), and no wavelength shifts were observed. Temperature and time of storage exert in general no significant effect on the development of fluorescence emission intensity and browning index. However, an important increase in pentodilysine was recorded-probably because of the iron and ascorbic acid contents of the samples-as well as in browning index in adapted IF. In both IF a color increase (deltaE) throughout storage was observed, this increase being greater in samples stored at 37 degrees C than in those stored at 20 degrees C. The increase in color with time fitted a linear regression model. Color appeared to be an indicator of sufficient sensitivity to measure the effect of temperature or storage time.
Influence of high-oryzanol rice bran oil on the oxidative stability of whole milk powder
- J N Nanua
- J U Mcgregor
- J S Godbert
- P Nozi Ere
- B Graulet
- A E Lucas
- B C R Martín
- P Grolier
- M T Doreau
Nanua, J. N., McGregor, J. U., & Godbert, J. S. (2000). Influence of high-oryzanol rice
bran oil on the oxidative stability of whole milk powder. Journal of Dairy Science,
83, 2426e2431.
Nozi ere, P., Graulet, B., Lucas, A. E., Martín, B. C. R., Grolier, P., & Doreau, M. T. (2006).
Carotenoids for ruminants: From forages to dairy products. Animal Feed Science
and Technology, 131, 418e450.