CIELAB Color Values Research Articles

Development of ginseng powder using high hydrostatic pressure treatment combined with UV-TiO2 photocatalysis

BackgroundKorean ginseng (Panax ginseng Meyer) powder is in rising demand because powder forms of foods are convenient to handle and are highly preservable. However, ginseng powder (GP) manufactured using the conventional process of air drying and dry milling suffers nutrient destruction and a lack of microbiological safety. The objective of this study was to prepare GP using a novel process comprised of UV-TiO2 photocatalysis (UVTP) as a prewashing step, wet grinding, high hydrostatic pressure (HHP), and freeze-drying treatments. MethodsThe effects of UVTP and HHP treatments on the microbial population, ginsenoside concentration, and physiological characteristics of GP were evaluated. ResultsWhen UVTP for 10 min and HHP at 600 MPa for 5 min were combined, initial 4.95 log CFU/g-fw counts of total aerobes in fresh ginseng were reduced to lower than the detection limit. The levels of 7 major ginsenosides in UVTP-HHP–treated GP were significantly higher than in untreated control samples. Stronger inhibitory effects against inflammatory mediator production and antioxidant activity were observed in UVTP-HHP–treated GP than in untreated samples. There were also no significant differences in CIELAB color values of UVTP-HHP–treated GP compared with untreated control samples. ConclusionCombined processing of UVTP and HHP increased ginsenoside levels and enhanced the microbiological safety and physiological activity of GP.

Evolution and modeling of colour changes of red pepper (Capsicum annuum L.) during hot air drying

In current work, the evolution kinetic models of moisture, surface colour (L∗, a∗, and b∗), natural pigment and non-enzymatic browning (NEB) of red pepper during hot air drying at drying temperatures of 60, 70, and 80 °C were investigated. The relationships between surface colour and natural pigment, as well as non-enzymatic browning were explored. Results showed that, the drying time of red pepper decreased with the increase of drying temperature, Weibull model fits the drying curves well. By comparing the fitting of kinetic models to the experimental data, it was found that the evolution kinetics of surface colour (L∗, a∗, and b∗) and NEB followed the Weibull and zero-order model, respectively. The degradation of natural pigment fitted well to both the Weibull and first-order model. The activation energy for L∗, a∗, b∗, natural pigment and NEB evolution were 42.47, 42.83, 44.92, 37.22, and 56.68 kJ/mol, respectively, which indicates that browning was most sensitive to heat. Furthermore, the surface colour parameters showed a positive correlation with natural pigment content, and a negative correlation with NEB. Equations to predict the concentration of the natural pigment in red pepper on the basis of CIELAB colour values were obtained.

The study of colour fastness of commercial microencapsulated photoresponsive dye applied on cotton, cotton/polyester and polyester fabric using a pad‐dry‐cure process

Commercial microencapsulated photoresponsive dye was applied on cotton, polyester/cotton and polyester fabric using a pad‐dry‐cure process. Colour fastness of the photoresponsive fabrics to washing, wet cleaning, dry cleaning, rubbing and light was investigated. The CIELAB colour values of the fabrics before and after testing were measured using a reflectance spectrophotometer, and the colour differences were calculated to evaluate the fastness properties. The fabrics had better colour fastness to wet cleaning and washing than to dry cleaning. The fabrics showed higher colour fastness to wet than to dry rubbing. The photoresponsiveness of the fabrics decreased with prolonged exposure time to artificial light due to low photostability of the microcapsules.

Yield estimation of 1-year-old asparagus grown using rootstock-planting forcing culture

ABSTRACTRootstock-planting forcing culture was developed in asparagus to harvest spears even during the seasons when the plants become dormant, but the demand for them high. In this study, cumulative hours during which the air temperature remained lower than 5°C, i.e. chilling hours (CHs), were calculated to determine dormancy breakage for asparagus cultures. We also measured CIELab colour values for cut stems immediately before rootstock digging, and determined whether they could be substituted and/or compensated for CHs while evaluating asparagus plant productivity in different low-temperature backgrounds, and obtained regression equations for yield estimation. Asparagus seedlings were cultivated in seven different regions across Japan and brought to the study site for harvesting. Our regression equation based on CHs and rootstock weight for yield estimation had relatively high fitness (adjusted R2 = 0.5795). The colour values of cut stalks at rootstock digging can also be used to evaluate their productivity. These values can be useful in regions where CHs cannot be determined, although their effectiveness was slightly lower than that of CHs of areas adjacent to the study sites.

Evaluation of the effect of ultraviolet stabilizers on the change in color of a silicone elastomer following aging by three different methods:An in vitro study

Aim and objective-To compare and evaluate the effect of UV stabilizers (UV absorbers and Hindered Amine Light Stabilizers-HALS) on the colour change of a commonly used silicone elastomer subjected to ageing by three different methods. Materials and methods4 groups of 30 samples each were studied; Group A-Control, Group B-Silicone+ UVA (Chimassorb 81),Group CSilicone+ HALS (Uvinul 5050) and Group D-Silicone + Combination (UVA+ HALS) (Chimassorb 81+Uvinul 5050). Each group was further divided into groups of 10 samples each based on the method of ageingaccelerated weathering chamber (Weather-Ometer), artificial perspiration and a cleansing agent. CIE Lab colour values L*, a* and b* were measured for all samples before and after weathering and change in colour (Delta-E) was calculated. One-way ANOVA was applied to compare the mean values of the 4 groups and the Post Hoc Tukey test was carried out to compare between 2 groups. ResultsAll groups showed a significant colour change. For Group A the colour change (average Delta E) for accelerated weathering, artificial perspiration and cleansing agent was 1.479, 0.617 and 0.62 respectively. Similarly, for Group B it was 1.109, 0.509 and 0.507; for Group C it was 1.866, 0.652 and 0.997 and for Group D it was 1.303, 0.829 and 1.033 respectively. UVA (Chimassorb 81) showed the least change consistently in all 3 types of ageing. Conclusion-Addition of UV stabilizer Chimassorb 81 showed a reduction in colour change of the silicone elastomer. Following studies on the effect of these additives on the physical properties of elastomers has shown that they can have a potential use in maxillofacial prosthetic rehabilitation.

UV protective properties of cotton fabric treated with plasma, UV absorber, and reactive dye

The influence of water vapor plasma on the adsorption of UV absorber during the reactive dyeing of bleached and mercerized cotton fabric was examined. Exhaust dyeing of untreated and plasma-treated cotton was performed using a reactive dye Cibarcon Deep Red S-B and a commercial UV absorber Tinofast CEL. Blank dyeing was performed as a control experiment. Fourier transform infrared spectroscopy (FTIR) was used to identify the presence of the UV absorber on the cotton fabric, whereas scanning electron microscopy (SEM) and X-ray photoelectron spectroscopy (XPS) were used to analyze surface changes of untreated and plasma-treated dyed samples. The CIELAB color values and ultraviolet protection factor (UPF) of the samples were determined spectrophotometrically. Wash and light fastness of samples was performed also. The results reveal that the UPF of cotton increases after UV absorber treatment and that plasma treatment increases the adsorption of UV absorber during dyeing process, especially at higher dye concentrations. The enhanced adsorption of UV absorber onto plasma-treated cotton is the result of the increased concentration of oxygen containing functional groups on the cotton surface after plasma treatment, confirmed by XPS. The UPF of plasma-treated cotton samples is decreased after washing and increased after exposure to xenon light.

Physicochemical composition of buffaloberry (Shepherdia argentea), chokecherry (Prunus virginiana) and sea buckthorn (Hippophae rhamnoides) fruit harvested in Saskatchewan, Canada

Green, R. C. and Low, N. H. 2013. Physicochemical composition of buffaloberry ( Shepherdia argentea ), chokecherry ( Prunus virginiana ) and sea buckthorn ( Hippophae rhamnoides ) fruit harvested in Saskatchewan, Canada. Can. J. Plant Sci. 93: 1143–1153. There is increasing interest in the commercialization of native fruits for utilization as foods and medicinal extracts. This study was undertaken to determine the physicochemical properties of buffaloberry (Shepherdia argentea), chokecherry (Prunus virginiana) and sea buckthorn (Hippophae rhamnoides) fruit grown in Saskatchewan. The physicochemical analyses of samples of each of these fruits included carbohydrate content, CIELAB color values, organic acid composition, pH, percent seed weight, phenolic compound content, soluble solids content, total titratable acidity (TTA) and proximate composition (ash, fibre, lipid, moisture and protein). Buffaloberry was found to contain high TTA and was especially high in ascorbic acid at 209±37 mg 100 g−1 fruit, fresh weight basis. Chokecherry contained high levels of anthocyanin at 237±41 mg 100 g−1 fruit, fresh weight basis. The results of this study suggest all of these native fruits possess compounds important to the human diet.

Technological and quality characteristics of cooked ham-type pâté elaborated with sheep meat

The use of meat from adult sheep to replace (at 0, 25, 50, 75 or 100% final concentrations) the pork meat in a ham-type pâté formulation was studied and several technological and sensory quality properties were determined. The test results demonstrated no significant (P>0.05) differences in the chemical composition (water, proteins, lipids and ash contents), pH, water activity, oxidation index according to the TBARS value and the consistency of the different treatments. The content of total and nitrous heme pigments in the pâtés containing sheep-meat were higher (P<0.05) than in the ham pâté, but the percentage of conversion of the heme pigments to the nitrous form was not affected (P>0.05). According to the CIELAB color values, the samples became (P<0.05) darker (less L*) and redder (high a*, C* and h* values) as the sheep-meat content was increased. However, these color alterations did not affect (P>0.05) the overall sensory impression of consumers and the pâtés containing sheep meat achieved a preference value similar to that of the ham pâté. The use of meat from discarded sheep in the preparation of pâtés conferred higher added value to this product and generated a new product with quality characteristics and sensory acceptance similar to that of ham pâté.

Properties of ink‐jet printed, ultraviolet‐cured pigment prints in comparison with screen‐printed, thermo‐cured pigment prints

A collection of printed fabrics for men’s shirts was designed and prepared using computer‐aided design/computer‐aided manufacturing technology. The colours for designs were ink‐jet printed on cotton fabrics with pigments and ultraviolet‐cured. These prints represented the target colours for subsequent flat‐screen printing, which was performed using pigment printing pastes and thermal curing. For an exact transfer of colours of the ink‐jet‐printed standard into the screen‐printing process, a computer recipe prediction method was used. A comparison of colorimetric parameters of fabrics printed with both printing techniques shows minimal and acceptable differences in the CIELab colour values. A comparison of colour fastness properties proves that very good colour fastness is achieved on the pigment‐printed fabrics produced with both printing techniques. The flat‐screen‐printed fabrics show better colour fastness to washing, perspiration and rubbing, while ink‐jet‐printed fabrics show better colour fastness to dry‐cleaning and light. The fabrics printed with both printing techniques have high rigidity and non‐elastic properties. The mechanical and physical parameters are strongly dependent upon the amount of the dry substance of the printing media applied on the cotton fabric surface, which is higher on screen‐printed fabrics. The ink‐jet‐printed fabrics show better air permeability than flat‐screen‐printed fabrics.

Colorful Drying

Drying is one of the standard unit operations in the pharmaceutical industry and it is important to become aware of the circumstances that dominate during the process. The purpose of this study was to test microcapsulated thermochromic pigments as heat indicators in a fluid bed drying process. The indicator powders were manually granulated with alpha-lactose monohydrate resulting in three particle-size groups. Also, pellets were coated with the indicator powders. The granules and pellets were fluidized in fluid bed dryer to observe the progress of the heat flow in the material and to study the heat indicator properties of the indicator materials. A tristimulus colorimeter was used to measure CIELAB color values. Color indicator for heat detection can be utilized to test if the heat-sensitive API would go through physical changes during the pharmaceutical drying process. Both the prepared granules and pellets can be used as heat indicator in fluid bed drying process. The colored heat indicators give an opportunity to learn new aspects of the process at real time and could be exploded, for example, for scaling-up studies.

The effect of bleaching agent on the flavor of liquid whey and whey protein concentrate

The increasing use and demand for whey protein as an ingredient requires a bland-tasting, neutral-colored final product. The bleaching of colored Cheddar whey is necessary to achieve this goal. Currently, hydrogen peroxide (HP) and benzoyl peroxide (BPO) are utilized for bleaching liquid whey before spray drying. There is no current information on the effect of the bleaching process on the flavor of spray-dried whey protein concentrate (WPC). The objective of this study was to characterize the effect of bleaching on the flavor of liquid and spray-dried Cheddar whey. Cheddar cheeses colored with water-soluble annatto were manufactured in duplicate. Four bleaching treatments (HP, 250 and 500mg/kg and BPO, 10 and 20mg/kg) were applied to liquid whey for 1.5h at 60°C followed by cooling to 5°C. A control whey with no bleach was also evaluated. Flavor of the liquid wheys was evaluated by sensory and instrumental volatile analysis. One HP treatment and one BPO treatment were subsequently selected and incorporated into liquid whey along with an unbleached control that was processed into spray-dried WPC. These trials were conducted in triplicate. The WPC were evaluated by sensory and instrumental analyses as well as color and proximate analyses. The HP-bleached liquid whey and WPC contained higher concentrations of oxidation reaction products, including the compounds heptanal, hexanal, octanal, and nonanal, compared with unbleached or BPO-bleached liquid whey or WPC. The HP products were higher in overall oxidation products compared with BPO samples. The HP liquid whey and WPC were higher in fatty and cardboard flavors compared with the control or BPO samples. Hunter CIE Lab color values (L*, a*, b*) of WPC powders were distinct on all 3 color scale parameters, with HP-bleached WPC having the highest L* values. Hydrogen peroxide resulted in a whiter WPC and higher off-flavor intensities; however, there was no difference in norbixin recovery between HP and BPO. These results indicate that the bleaching of liquid whey may affect the flavor of WPC and that the type of bleaching agent used may affect WPC flavor.

Analysis of Fish Fillet Drying Rates under Three Solar Energy Drying Systems

A small Box type solar dryer with controllable air inlet was designed and tested. The dryer had a mild steel absorber plate and a polyvinyl chloride (pvc) transparent cover and could be adjusted to allow variation in airflow rate through the drying chamber. A convectional green house covered with transparent pvc and into which a drying tray stand at a height of 90 cm above the ground was placed made up the second drying method. The rate of air flow through the green house could be controlled by adjusting the opening at either end of the tunnel. The third method of drying which also served as the control is sun drying in which case the drying trays was placed 90 cm above the ground but left unenclosed to allow free flow of ambient air. The air temperature at points just above the drying rack was monitored for all three drying systems under no load conditions from morning to late afternoon. The temperature was also monitored during drying when the trays were loaded with fish of different fillet thicknesses. The rate of loss of moisture was also monitored by weighing the fillets at regular interval until the moisture dropped to 20%, dry basis or lower. The average temperature inside the plenum chamber of the box type solar dryer was found to have a high daily value of 71.1OC although an absolute maximum value of 74.4OC was recorded. This maximum value could be reached on cloudless days between the hours of 13:00 and 1400. The green house recorded a slightly lower average temperature and its peak value occurred latter in the day. Both the green house and the box-type solar dryer had average drying chamber temperatures that were more than 30 centigrade degrees above ambient conditions. Both the box-type and green house type solar dryer could dry thin slices of fish fillet in 1-3 days as opposed to the 7-9 days normally required under sun drying conditions. The quality of the dry fillet was satisfactory and CIE LAB colour values did not change significantly during drying.

Principal Component Regression Analysis of the Relation Between CIELAB Color and Monomeric Anthocyanins in Young Cabernet Sauvignon Wines

Color is one of the key characteristics used to evaluate the sensory quality of red wine, and anthocyanins are the main contributors to color. Monomeric anthocyanins and CIELAB color values were investigated by HPLC-MS and spectrophotometry during fermentation of Cabernet Sauvignon red wine, and principal component regression (PCR), a statistical tool, was used to establish a linkage between the detected anthocyanins and wine coloring. The results showed that 14 monomeric anthocyanins could be identified in wine samples, and all of these anthocyanins were negatively correlated with the L*, b* and H*ab values, but positively correlated with a* and C*ab values. On an equal concentration basis for each detected anthocyanin, cyanidin-3-O-glucoside (Cy3-glu) had the most influence on CIELAB color value, while malvidin 3-O-glucoside (Mv3-glu) had the least. The color values of various monomeric anthocyanins were influenced by their structures, substituents on the B-ring, acyl groups on the glucoside and the molecular steric structure. This work develops a statistical method for evaluating correlation between wine color and monomeric anthocyanins, and also provides a basis for elucidating the effect of intramolecular copigmentation on wine coloring.

Influence of Enzymatic Pretreatment on the Colours of Bleached and Dyed Flax Fibres

SUMMARY In this paper the effect of enzymatic bioscouring on the bleaching and dyeing of flax fibres was studied in comparison with conventional alkaline scouring. Enzymatic bioscouring was performed with a commercial multi-enzyme system consisting of pectinases, hemicellulases and cellulases. The enzyme and alkaline scoured flax fibres were subsequently oxidatively bleached with hydrogen peroxide and dyed with direct dye C.I. Direct Red 80 under the same conditions. The efficiency of both the scouring and bleaching processes was evaluated by weight loss and the whiteness of the bleached samples was determined according to CIE formula. The exhaustion profile of the used dye was followed on-line during the dyeing process using absorbance measurement. The colours of bleached and dyed samples were evaluated using CIELAB colour values. The residual pretreatment and dyeing baths were ecologically analysed with COD, TOC and BOD5. The obtained results indicate that enzymatic scouring provides a lower weight loss, a higher degree of whiteness, comparable dyeing properties and is more environmentally friendly.

Pre-visual detection of iron and phosphorus deficiency by transformed reflectance spectra

Reflectance spectroscopy and strategies for spectral analysis over the visible range from 380 to 780 nm were used to provide diagnostic information on iron (Fe) and phosphorus (P) status of Brassica chinensis L. var parachinensis (Bailey) grown under hydroponics conditions. Leaf reflectance ( R) spectra were collected and normalized inner reflectance (NR I) spectra were calculated. The regression coefficients (B-matrix) and variable importance for projection (VIP) in partial least squares regression were used to determine important wavelengths that correlate with total chlorophyll (Chl) content. No single wavelength that showed good correlation with Chl content was found. Therefore, NR I was transformed into CIELAB color values, which simplified the whole visible spectrum into three values. Our results showed that upon Fe deprivation, plants entered into a deficiency state very rapidly, highlighting the importance of early diagnosis. The direct effect of Fe on leaf Chl content allowed CIELAB color values to be used for pre-visual detection of Fe deficiency 2 days before the appearance of visually distinguishable morphological changes. On the other hand, P-deprived plants showed a marked decline in cellular P levels but remained above critical threshold concentrations after 7 days. The Chl content was not affected by the leaf P content and CIELAB color values showed no difference with control plants.

Influence of inulin modification and flour type on the sensory quality of prebiotic wafer crackers

An inulin syrup made from Jerusalem artichoke tubers, either in its commercial form or after ultrafiltration, was freeze-dried and used as a prebiotic ingredient in the small-scale manufacture of wafer crackers. The flours used for the preparation of wafer batters were from wheat, rye or spelt wheat, or 1:1 combinations of wheat flour and rye flour or wheat flour and spelt wheat flour. Batter viscosity was strongly influenced by the selection of the flour type, but remained within technologically acceptable limits. The ultrafiltration of the inulin syrup, using a 1 kDa membrane, resulted in a significant reduction of the content of free sugars and minerals which, in turn, had a significant impact on the CIE-Lab color values of the wafer crackers. Using spelt wheat flour instead of wheat flour significantly increased wafer cracker firmness measured by penetration, as did the incorporation of ultrafiltered freeze-dried instead of native freeze-dried Jerusalem artichoke syrup. Sensory analysis revealed a significant influence of product formulation on appearance, flavor and texture of the wafer crackers. It can be concluded from quality scores, which were calculated by using weighting factors assigned to the sensory attributes, that wheat flour may be partially replaced by rye flour or spelt wheat flour without negatively affecting the sensory properties of the wafer crackers.

Digital colour matching in restorative dentistry

Objective To develop a shade matching method based on digital imaging and to compare observers' ability using this method with the conventional one set against a spectrophotometric 'gold standard'. Methods Two Vita Lumin shade guides were used in this study, nine shades being selected from the first Vita Lumin shade guide, A2, A3, A3.5, B2, B3, B4, C1, C2 and C3. A second shade guide was used to match the selected shades. A Nikon Coolpix 990 digital camera with Nikon SB21B ring flash was used to record the digital images of the shade tabs of the two shade guides and the images were processed using Adobe Photoshop software. A total of 27 samples (three replicates of each shade of the nine tabs selected) were matched with a digital shade guide prepared from the digital images of the second shade guide by 10 observers on a computer screen (computerised matching method). The 10 observers also matched the same shade tabs using the conventional matching method simulated in a phantom head. In addition colour values were obtained from the digital images using Adobe Photoshop and quantified according to an internationally recognised scale as CIELAB colour values, L*,a*,b*. The relationship of the digitally derived CIELAB values to the CIELAB values obtained using a reflectance spectrophotometer was investigated. Results The cross tabulation statistical analysis showed a statistically significant difference (p<0.001) between the conventional method and the computer method with a 43% and 61.1% correct match respectively. There was also a statistically significant difference between observers in both methods (p<0.001 and p<0.04 for the conventional and computer methods respectively). A statistically significant high correlation of the CIELAB colour values were found between both colour measurement methods (p<0.001). Conclusion The observers' shade matching performance was significantly better with the computer method compared with the conventional one. There was a large variation in the observers' matching ability. The digital camera can be used as a means of colour measurements in the dental clinic.

The use of digital imaging for colour matching and communication in restorative dentistry

To develop a shade matching method based on digital imaging and to compare observers' ability using this method with the conventional one set against a spectrophotometric 'gold standard'. Two Vita Lumin shade guides were used in this study, nine shades being selected from the first Vita Lumin shade guide, A2, A3, A3.5, B2, B3, B4, C1, C2 and C3. A second shade guide was used to match the selected shades. A Nikon Coolpix 990 digital camera with Nikon SB21B ring flash was used to record the digital images of the shade tabs of the two shade guides and the images were processed using Adobe Photoshop software. A total of 27 samples (three replicates of each shade of the nine tabs selected) were matched with a digital shade guide prepared from the digital images of the second shade guide by 10 observers on a computer screen (computerised matching method). The 10 observers also matched the same shade tabs using the conventional matching method simulated in a phantom head. In addition, colour values were obtained from the digital images using Adobe Photoshop and quantified according to an internationally recognised scale as CIELAB colour values, L*,a*,b*. The relationship of the digitally derived CIELAB values to the CIELAB values obtained using a reflectance spectrophotometer was investigated. The cross tabulation statistical analysis showed a statistically significant difference (p<0.001) between the conventional method and the computer method with a 43% and 61.1% correct match respectively. There was also a statistically significant difference between observers in both methods (p<0.001 and p<0.04 for the conventional and computer methods respectively). A statistically significant high correlation of the CIELAB colour values were found between both colour measurement methods (p<0.001). The observers' shade matching performance was significantly better with the computer method compared with the conventional one. There was a large variation in the observers' matching ability. The digital camera can be used as a means of colour measurements in the dental clinic.

Post-mortem changes in the physical meat quality characteristics of refrigerated impala &lt;i&gt;M. longissimus dorsi&lt;/i&gt;

The effect of aging the M. longissimus dorsi of 13 impala at 4 oC over a ten-day period was investigated. Large variation between animals was observed for the percentages drip and cooking loss as well as for the CIELab colour (L*, a*, b*) values. No trend could be observed for these physical characteristics over time. Means for all traits correspond to that reported in the literature for this species. Similarly, the tenderness of the muscle varied between the animals. However, the tenderness (as measured by a Warner Bratzler shear apparatus) of the muscle generally improved with time. The quadratic equation y = -0.0817x2 + 0.4468x + 10.477 best described (R2 = 0.32) this improvement in tenderness. The implications of this result is that fresh game meat producers can de-bone carcasses after 24 hours post mortem and leave the primal cuts to age in vacuum bags in the chiller, thereby utilizing the available chiller space more efficiently. South African Journal of Animal Science Supp 2 2004: 26-28

Investigation of the antioxidant properties of tomatoes after processing

A study was made of the antioxidant content, activity and colour of two New Zealand commercially grown tomatoes ( Lycopersicon esculentum L . var. Excell and Aranca) cultivated in glasshouses using hydroponic techniques. Excell tomatoes were harvested and stored individually while cultivar Aranca was harvested by cutting the vine, which consisted of a group of eight tomatoes. Both cultivars of tomatoes were stored in the dark for 4 days at 15°C to simulate normal pre-purchase storing conditions. The antioxidant content of the raw tomatoes after 4 days of storage were markedly different while the CIE LAB colour values of the cut inner surfaces of the two cultivars were similar. After 4 days storage, subsamples of each cultivar were either boiled, baked or fried, and analysis of CIE colour, ascorbic acid, total phenolics, lycopene and antioxidant activity (using the ABTS assay) was undertaken. Boiling and baking had a relatively small effect on the ascorbic, total phenolic, lycopene and antioxidant activity of the two cultivars while frying significantly reduced ( P<0.001) the ascorbic, total phenolic and lycopene contents of the two cultivars. Chromatic colour analysis showed that both cultivars became significantly ( P<0.001) darker and less red after cooking by all methods. In a following experiment, the two cultivars of tomatoes were sliced and allowed to soak for 20 min in a mixture of olive oil and white vinegar, or olive oil and white vinegar separately. CIE colour of the two cultivars showed no change after processing but the treatments of oil and vinegar separately and together reduced ( P<0.05) the red component of the colour. Treating the two cultivars of tomatoes with the oil and vinegar mixture resulted in a significant reduction ( P<0.001) in the ascorbic acid, total phenolic and antioxidant activity of the tomatoes. Treatment with oil significantly reduced the amount of lycopene that could be extracted from the tomatoes while treatment with vinegar had no effect.