Physical Aspects of Color in Foods

Joshi, Prabesh

doi:10.1021/bk-2001-0775.ch003

Cited by 6 publications

(3 citation statements)

References 1 publication

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“…Francis (1987) stated that one of the major problems in comparison of tristimulus data obtained from food is the use of instruments with different designs. In addition, food samples are not flat, or perfectly opaque/transparent, and or of a single uniform color; the physical environment can sometimes be more influential than the colorant itself (Joshi 2001). Previous studies have evaluated color measurement of food in liquid (Kent 1987) and powder forms (Brimelow 1987; McDougall 1987).…”

Section: Introductionmentioning

confidence: 99%

Color Quality of Oregon Strawberries—Impact of Genotype, Composition, and Processing

Ngo

Wrolstad

Zhao

2006

Journal of Food Science

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This investigation was to evaluate fruit color and study the effect of processing on color quality of strawberry products. Three color instruments with different viewing angles, viewing areas, and sample presentation geometries were compared for their effectiveness in measuring CIEL*C*h(o) color values for fresh fruits of 6 strawberry genotypes. There were significant differences between genotypes as well as between instruments. Fruits from the Totem genotype were frozen, canned, and made into jam. Color changes were measured along with the following compositional determinations: total monomeric anthocyanins (ACN), total phenolic content (TPC), and percent polymeric color. ACN in fresh strawberries ranged from 37.1 mg to 122.3 mg per 100 g of fresh fruit. Freezing resulted in an apparent increase in ACN and transfer of 70.2% of the anthocyanins from the berries into juice. Physical transfer of pigments to syrup also occurred with canning: there was approximately 70% loss in ACN, about 20% increase in polymeric color, and 23.5% decrease in TPC. Pronounced color change and substantial losses in ACN and TPC of strawberry jams occurred during processing and 9 wk of storage. Storage of jams at 38 degrees C compared to 21 degrees C over a period of 9 wk resulted in marked losses of ACN and TPC.

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Section: Introductionmentioning

confidence: 99%

Color Quality of Oregon Strawberries—Impact of Genotype, Composition, and Processing

Ngo

Wrolstad

Zhao

2006

Journal of Food Science

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“…Significantly higher L* value was observed only for UFD powder, which probably influenced the ΔE* value. This might be due to the scattering of the incident light from the increased particle surfaces throughout a range of angles [ 39 ] relative to the smaller size of the powder particles [ 40 ].…”

Section: Resultsmentioning

confidence: 99%

Stinging Nettles as Potential Food Additive: Effect of Drying Processes on Quality Characteristics of Leaf Powders

Chakravartula

Moscetti

Farinon

et al. 2021

Foods

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Stinging nettle (Urtica dioica L.) is a ubiquitous, multi-utility, and under-utilized crop with potential health benefits owing to its nutritional and bioactive components. The objective of the work is to produce powders by drying wild stinging nettle leaves as a storable, low-cost functional additive to be used in bakery and ready-to-cook products. Convective drying (CD) and freeze-drying (FD) were applied on unblanched (U) or blanched (B) leaves, which were then milled to nettle powders (NPs). The obtained NPs were evaluated for selected physicochemical (moisture, color), techno-functional (flow indices, hygroscopicity), and phytochemical (pigments, phenols) characteristics as well as mineral contents. Blanching improved mass transfer and reduced the oxidative degradation of pigments during drying, but it caused a loss of total phenols content, antioxidant activity, and potassium content. As for the drying method, CD resulted in better flow properties (i.e., Carr Index and Hausner Ratio), while FD retained better the color, pigments, magnesium content, phenolic, and antioxidant parameters. Overall, the evaluated processing methods resulted in different technological properties that can allow for better evaluation of NPs as a food additive or ingredient. Among the NPs, blanched and freeze-dried powders despite showing inferior technological properties can be recommended as more suitable ingredients targeted f or food enrichment owing to better retention of bio-active components.

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“…As it is well known, the absorbance of an absorbing dye solution is governed by the Beer-Lambert law (Joshi 2000), which establishes the proportionality between absorbance and concentration for a given optical path length. of the initial rate of extraction shown in Table 1.…”

Section: Resultsmentioning

confidence: 99%

Effect of temperature on the evolution of colour during the maceration of fruits in liquor

Paz¹,

Fernández²,

Matías³

et al. 2014

Czech J. Food Sci.

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Paz I., Fernández A., Matías C., Pinto G. (2014): Effect of temperature on the evolution of colour during the maceration of fruits in liquor. Czech J. Food Sci., 32: 90-95.The effect of temperature on the kinetics of pigment extraction during the maceration of different fruits (raspberry, blackberry, and cranberry) into a commercially available hard spirit (orujo, with 42% v/v ethanol) was evaluated. The analytical method used was UV-Vis spectrophotometry. The initial extraction rate showed an Arrhenius-type dependence with apparent energy activation of 28.8, 69.8, and 55.6 kJ/mol, respectively. Furthermore, a study about the evolution of the colour (from colourless to reddish colour appearance) during the soaking process was done by calculating the CIE tristimulus values (X, Y, Z) for illuminant C, until reaching the apparent stabilisation of colour, which occurs after about two to four weeks for the studied temperatures (5, 23, and 40°C). Studies about the evolution of colour in the soaking process of this kind of fruit liquors can lead to a better understanding of this process, and thus to a better control over the mechanisms underlying it.

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Physical Aspects of Color in Foods

Cited by 6 publications

References 1 publication

Color Quality of Oregon Strawberries—Impact of Genotype, Composition, and Processing

Color Quality of Oregon Strawberries—Impact of Genotype, Composition, and Processing

Stinging Nettles as Potential Food Additive: Effect of Drying Processes on Quality Characteristics of Leaf Powders

Effect of temperature on the evolution of colour during the maceration of fruits in liquor

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