Instrumental Color Measurements Research Articles

Instrumental color measurements of automotive samples with convex cylindrical curvatures under diffuse lighting

Instrumental color measurements of automotive samples with convex cylindrical curvatures under diffuse lighting

The effect of dry and wet aging of horse meat on color

The color of horse meat may depend on several factors, including storage conditions, animal type and age, as well as meat processing methods. Studies aimed at comparing the color of dry aging and wet aging of horse meat have not been the subject of much scientific research. The purpose of the study is to study the effect of dry and wet aging of horse meat on color. The object of research is a boneless dorsal cut of horse meat. Meat samples were isolated 24 hours after slaughter and stored (2 ± 5 °C) in a dark place. Eight samples of horse meat were cut from a boneless dorsal cut, and then randomly distributed according to the periods and aging method. Two control samples - 1 day, three samples of dry aging – 14, 21, 28 days. Wet aging of horse meat was carried out in vacuum packed form in a refrigerated product storage chamber at a temperature of 2±1 °C and relative humidity of no more than 90% for 28 days. Instrumental color measurements were carried out on the L*, a* and b* scales using a Minolta colorimeter (Minolta CR-400, Osaka, Japan) installed with a D65 illuminator, viewing angle 2°. The differences in the indicator of Lightness L* in meat of dry and wet aging for 14 days were 1,785, at 21 days - 3,784 and 28 days - 10,754, in terms of Redness, a* 11,626 - at 14 days, 13.0841 and 15.1253 were 21 and 28 days, respectively. The difference in Blue, b* was 8.6054, 13.3676, 12.3517 for 14.21 and 28 days. The obtained color differences, ΔE* 17,1346, 21,192, 26,64 indicate that the method of aging of horse meat has a significant effect on its color.

Comparative study of the quality of breast meat of free-range chicken (Gallus gallus domesticus) and conventional chicken (Gallus gallus).

This study compares the physicochemical characteristics of breast meat (Pectoralis major) from conventional chicken and free-range chicken production systems. Analyses of pH, instrumental color measurement, weight loss from cooking (WLC), and water retention capacity (WRC) were carried out. Average pH values were slightly higher for conventional chicken samples. WLC did not show a significant difference between conventional and free-range chicken samples. The WRC was better and higher for the free-range chicken samples than the conventional ones. The mean values for luminosity (L*) were within the normal range, with slightly higher values for conventional chicken. In chromatids a* and b*, there was a tendency towards a more reddish color for free-range chicken samples. The differences found for types of production can be explained mainly by the difference in age at slaughter, the degree of physical activity, animal feeding, among other characteristics that differentiate an animal raised by the extensive system from the intensive system.

27 Quality Variation in Beef Chuck Eye Rolls Sourced from a Commercial Processor

Abstract The objective of this study was to evaluate quality variation in beef Chuck Eye rolls (IMPS 116D). Beef Chuck Rolls (IMPS 116A) were purchased from a commercial meat packer and fabricated to obtain beef Chuck Eye Rolls (IMPS 116D). Cases were transported to the Illinois State University Meat Lab and hand-sliced into 2.54 cm boneless beef Chuck Eye steaks (IMPS 1116D) (n = 161). Each roll contained between 7 to 10 steaks for use in further meat quality analyses in accordance with in-plant procedures. Upon slicing, steaks were allowed to bloom for 15 minutes and then used in subsequent quality analysis including color, cook loss, and tenderness evaluation. Instrumental color measurements [L* (lightness), a* (redness), b* (yellowness)] were taken for each steak in duplicate with a HunterLab Miniscan XE Plus Spectrophotometer using a D65 illuminant, 100 observer, and 35-mm aperture. All steaks were cooked to a final internal temperature of 71° C. Steaks then underwent cook loss evaluation as well as tenderness analysis via Warner-Bratzler shear force (WBSF). Statistical analysis was performed using the Proc MIXED procedure of SAS to estimate variance components of steak quality in a nested design (steak within roll within case). For all response variables, the standard error was large for the case term. Ranges of observed response values were: L* 28.03-52.15, a* 14.55-27.82, b* 12.78-25.32, cook loss 17.58-61.11, shearforce 2.10-5.86. Variance components in L* and a* values followed similar patterns in which the greatest amount of variance was contributed by steak, followed by case, followed by roll (L* 13.541 (P < 0.001) vs. 9.035 (P = 0.1790) vs. 1.958 (P = 0.1839) and a* 4.055 (P < 0.0001) vs. 1.605 ( P= 0.2124) vs. 0.632 (P = 0.1746). Case, roll, and steak contributed variance almost equally for b* though two variance components were statistically different from zero σ2case =2.133 (P = 0.2344) σ2roll = 1.627 (P = 0.0335) σ2steak = 2.37 (P < 0.0001). Case contributed approximately 1.5 times the variance in cook loss when compared with steak (σ2case = 43.687 (P = 0.1387) vs. σ2steak=29.471 (P < 0.0001)) and approximately 3.5 times more than roll ( σ2case = 43.687 vs. σ2roll = 12.077 (P = 0.0565)). The largest impact on variance in shearforce values came from steak whereas case and roll contributed almost equally (shearforce σ2case = 0.0256 (P = 0.3894)σ2roll = 0.0333 (P = 0.2040) σ2steak = 0.2454 (P < 0.0001)). Some correlations were observed: L*:a* (-0.46, P < 0.0001), L*:b* (-0.07, P = 0.3979), L*:cookloss (0.166, P = 0.0422), and cookloss:shearforce (0.274, P = 0.0007). As lower-cost alternatives to traditional center of the plate cuts continue to grow in popularity among large volume purchasers, it is important to evaluate potential differences in quality attributes. Further evaluation of the impact of case as well as steak within Chuck Eye roll on individual steak quality is warranted.

The Content of Bioactive Compounds and Technological Properties of Matcha Green Tea and Its Application in the Design of Functional Beverages.

Matcha is a powdered green tea obtained from the Camellia sinensis L. plant intended for both "hot" and "cold" consumption. It is a rich source of bioactive ingredients, thanks to which it has strong antioxidant properties. In this research, an organoleptic evaluation was carried out, and the physical characteristics (i.e., instrumental color measurement (L*a*b*), water activity, water solubility index (WSI), water holding capacity (WHC) of 10 powdered Matcha green teas, and in the 2.5% Matcha water solutions, pH, °Brix and osmolality were tested. Also, the content of phenolic ingredients, i.e., selected phenolic acids, flavonoids and total polyphenols, was assessed. The content of chlorophyll, vitamin C and antioxidant potential were also examined. Matcha M-4 was used to design two functional model beverages, in the form of ready-to-use powdered drinks, consisting of Matcha green tea, protein preparations, inulin, maltodextrin and sugar. The obtained powdered drink, when dissolved in the preferred liquid (water, milk, juice), is regenerative, high-protein and rich in bioactive ingredients from the Matcha drink, with prebiotic properties derived from the added inulin. The beverage is also characterized by low osmolality. It can be recommended as a regenerating beverage for a wide group of consumers, athletes and people with deficiencies, among others protein, and elderly people, as well as in the prevention and supportive treatment of bone and joint tissue diseases.

French Fries’ Color and Frying Process in Relation to Used Plant Oils

Fast-food establishments today often sell fried food without proper control over the frying oil, and french fries are a prime example. Neglecting the maintenance of frying oil can lead to decreased taste, health concerns, and operational inefficiencies. The following plant oils were used in the frying process: rapeseed, sunflower, and palm oil. The degree of frying was measured by the total polar meter (TPM), until the achievement of 24%. To accurately assess the color characteristics of the french fry samples, Minolta CM 2600d color measurement instrument was used. Statistically significant differences were observed between some color parameters (L, a, b, C, and h) and TPM values. The following correlations were observed: 0.530 was obtained for TPM and h (hue angle) in french fries fried in palm oil; negative correlation (−0.214) between TPM and L (lightness) was obtained in french fries fried in rapeseed oil. While we have observed certain correlations from our experimental data, it is important to note that the color of french fries may not be the sole determinant of fried oil quality. Other external factors, such as temperature, chemical composition, and potato cultivar, can also significantly influence the color of french fries.

Exploring the Effects of Incorporating Egg Powder Containing Phospholipase α2 Antibody on Ground Striploin Shelf-Life

Lipid oxidation in beef may be enhanced by the hydrolysis of phospholipids by phospholipaseα2 (PLA2) during postmortem storage. Anti-phospholipaseα2 (aPLA2) is an antibody that can inhibit PLA2 activity. Past research has shown that aPLA2 can be mass-produced in the form of egg powder (EP) from hens immunized against PLA2. Therefore, the present study aimed to determine the effects of incorporating different levels of EP containing aPLA2 into ground striploin (GS) to assess its ability to extend beef shelf-life. Ten striploins were collected from 10 USDA Choice beef carcasses. Each striploin was ground and equally divided into 4 batches, and each batch was mixed with 0%, 0.4%, 0.8%, or 1.6% dried EP containing aPLA2. Each treatment batch was further divided into 3 smaller batches and subjected to retail display (0, 4, or 7d). Color descriptors, pH, proximate analysis, lipid oxidation, antioxidant capacity, and phospholipid and fatty acid (FA) profiles were measured. Percent visual discoloration and instrumental color measurements of GS were unaffected by aPLA2 EP treatments (P>0.05). The 1.6% treatment GS had a higher relative percentage of phosphatidylcholine compared with those from the 0% treatment (P<0.05), but the lack of lysophosphatidylcholine generation in the GS from any treatment reflects a lack of detectable level of PLA2 activity. Moreover, the addition of EP in GS increased the relative percentage of FA 11-18:1, 18:2, 20:1, and 22:6 (P<0.05). As a result, there was more lipid oxidation for GS from the 1.6% treatment compared with those from the 0% treatment (P<0.05), but GS from the 0.8% treatment showed higher antioxidant activity than those from the 0% treatment (P<0.05). In this study, the addition of EP containing aPLA2 did not demonstrate any effect to extend shelf-life when incorporated into GS.

Visual color inspection with a hyperspectral camera: inline application for automotive parts production

The development of cars is becoming increasingly focused on colour, which is a major challenge for both suppliers and manufacturers. Manufacturers must establish strict colour tolerances for each coloured component and specify both colour and appearance. On the other hand, suppliers must maintain colour accuracy in part production, regardless of the type of material used, to ensure acceptance of colour by automotive manufacturers. In the colour industry, colour difference formulas are used to make unbiased judgments about whether manufactured goods should be approved or disapproved. These objective judgments are based on instrumental colour measurements that must accurately predict subjective colour variations. Hyperspectral imaging (HSI) has proven to provide helpful data for a variety of applications in numerous industries, including colour science. To measure and analyse colour differences between automotive parts, we proposed to use conventional colour science algorithms in conjunction with the Specim FX10 hyperspectral camera, which has a flexible infrastructure that can receive data from a Generic Interface for Cameras (GenICam) compatible with the Gigabyte Ethernet interface. The results showed that the use of hyperspectral imaging in production offers great potential for providing real-time colour information so that colour shifts can be detected early and costly errors in the production line can be avoided.

Lip color measurement: A new hyperspectral imaging device.

The lips are of significant interest among the facial features for self-perception and social interactions. Such perceptions could rely in part upon the contrast in color between the lips and the surrounding skin. In contrast to skin color, lip color ethnic diversity measurement provides a challenge and is less documented in the literature, most likely due primarily to challenges in measurement based upon the lip characteristics of size and contour. Accurate measurement and reproduction of lip color are essential to build strong cross-sectional knowledge about lip color. This preliminary experiment of a large-scale project on lip and skin color was designed to assess accuracy in lip color measurement and recommend instruments and protocols for good measurement practice. The study involved 19 healthy French Caucasian women. Their inferior and superior natural lip color was measured twice with three devices in order to extract the standard colorimetric parameters of lightness (L*), chroma (C*), and hue (h): the VISIA-CR® (high-resolution digital camera, Canfield Scientific Inc.); the spectrophotometer VS3200 (45°:0° spectrophotometer, MetaVue™ VS3200, X-Rite Inc.); and the SpectraFace® (new hyperspectral imaging system, Newtone Technologies). The intercomparison and color distribution between the different instruments and the measurement repeatability of each one were assessed. Our results showed a reliable and equivalent repeatability for the three tested instruments. Moreover, the three tools led to the same conclusion regarding lip color heterogeneity (lighter, redder, less yellow and more saturated inferior lip versus superior lip). Agreement between the SpectraFace® and the spectrophotometer measurements was higher, and the SpectraFace® allowed to identify three separated lip color typologies. In conclusion, the combination of imaging technology and hyperspectral measurement makes the SpectraFace® a useful tool to investigate lip color characterization and establish a large-scale cross-sectional knowledge study about lip color.

Instrumental Color Measurements Have Relationships to Fat Smearing in Fresh Sausage.

Fat smearing, or poor fat particle definition, impacts the visual quality of sausage. However, objective methods of assessing fat smearing have not been identified. Therefore, the objective of this experiment was to determine the relationship between fat smearing and instrumental color analysis for fresh sausages to create a standard method for using instrumental color in fat smearing analysis. Meat blocks of pork (PK), beef (BF), and a mixture of pork and beef (P/B) were formed and processed at three different temperatures to create varying degrees of fat smearing. The average fat smearing score of each sausage was used to determine if a relationship existed with instrumental color measurements (CIE L*, a*, b*, and reflectance percentage at 580 nm and 630 nm) and color calculations. A correlation was observed for L* (R = -0.704) and the reflectance at 580 nm (R = -0.775) to PK fat smearing (p < 0.05). In P/B sausage, both reflectances at ratios between 630 nm and 580 nm were correlated to P/B fat smearing. No measurement or calculation was correlated with BF fat smearing (p > 0.05). Therefore, it is possible to use instrumental color analysis for the evaluation of fat smearing in pork and pork/beef blended sausage products, but not in beef sausage products.

Comparative analysis of cattle, buffalo and bison meat

Nowadays, the consumption of bison meat is becoming more widespread worldwide, while it’s experiencing a renaissance in the United States. For the industry, this could lead to the emergence of a new market sector in the future. It is important to examine the extent to which the quality of its meat differs from that of the usual cattle or buffalo returning to the public consciousness. Our measurements were performed on the loin of bison, buffalo and cattle, including Angus cattle based on the consumer price per 100 grams of product, instrumental colour measurement, instrumental stock measurement, cooking, roasting and pressing loss, instrumental analytical examination and sensory evaluation. During our research, we concluded that bison meat may become a very popular product in Hungary in the future. There is a clear place for the consumption of both buffalo meat and bison meat in a health-conscious diet based on the measured results.

Use of High-Pressure Processing to Improve the Redness of Dark-Cutting Beef

The objective was to evaluate the effects of high-pressure processing (HPP) levels on retail color of dark-cutting beef. Eight USDA Choice (mean pH=5.5; normal-pH beef) and 12 dark-cutting (mean pH=6.3) strip loins were obtained from a commercial packing plant within 2 d of harvest. Dark-cutting loins were cut into equal sections, vacuum packaged,and randomly assigned to 0 (no HPP), 300, 450, and 600 MPa of pressure for 90 s using chilled water. Following 48 h of dark storage at 2°C, dark-cutting loin sections were cut into 1.9-cm-thick steaks, placed in Styrofoam trays overwrapped in polyvinyl chloride (PVC) film, and placed in a simulated retail display for 8 d. The surface color readings were measured every 24 h using a HunterLab MiniScan XE Plus spectrophotometer, whereas a trained color panel (n=6) evaluated dis-coloration, paleness, and lean color on steaks. Lipid oxidation was evaluated on day 0, 4, and 8 of retail display, and structural changes were determined using light microscopy on day 0 of display. There was a significant HPP level×day of retail display interaction for all instrumental color measurements. Throughout the retail display, L* values of 450 and 600 MPa applied steaks were greater (P&amp;lt;0.05) than 300 MPa and controls. There was a significant pressure level×day of retail display interaction when panelists evaluated lean color and discoloration. Steaks treated at 300 MPa exhibited brighter red color and lower (P=0.0023) thiobarbituric acid reactive substance values than other pressure levels and normal-pH control steaks. Light microscopy analysis indicated that HPP increased space between muscle structures. In conclusion, low (300 MPa) and moderate (450 MPa) pressure levels can improve redness of dark-cutting steaks.

Assessing the effect of cleansing products on artificially polluted human hairs and skin through in vivo and in vitro models.

Based on in vivo data, in vitro models and new methods are created to mimic the impact of aerial pollution onto the hair surface and assess the efficacy of different formulae prototypes. Two protocols are developed to mimic the pollution effect, in vitro, on purchased swatches, and in vivo, on scalps and forearms. First, with an artificial sebum mixed with Carbon Black particles, named "sebollution," we evaluated, through an instrumental color measurement, the cleansing efficacy of some shampoo on scalp and hair. The second protocol allowed to assess the interaction between hair care product deposit (shampoo, conditioner, mask, and leave-on) on hair and carbon black particles spread on fiber. The quantification of particle coverage allowed to evaluate the efficiency of a formula to limit the aerial pollution deposit on hair fiber. To simplify and accelerate the evaluation of 42 shampoo formulae, an extrapolation of the scalp cleaning process was validated on forearm. The respective cleanabilities were calculated and covered a large range of efficacy, from 5%, for a basic bland shampoo generally used to reset swatches, to a strong deep cleansing efficacy of 100%. On hair swatches, cleanability efficiencies of five shampoo were also evaluated to eliminate the deposited of sebollution, in a range of 40%-80%. To quantify the efficacy of preventing the deposition of carbon particle on hair surface, the percentage of coverage of 45 different products was measured, from 2% to 16%. The performance depended of the product category (shampoo, conditioner, mask, and leave-on), driven by the performance of the product deposit, and the capacity of this deposit to interact with aerial pollution. Three new protocols and evaluation methods are proposed to evaluate and quantify the performance of hair care product, to remove/clean, limit, and protect the hair fibers against the aerial pollution that could interact with hair, scalp and sebum. The validation of these approaches was done through the testing of a large panel of hair care product leading to a complete and sincere evaluation of cleansing and anti-deposit efficacy. Combining the knowledge acquired on pollution impact on hair and the development of specific way of evaluation, this work reinforced the rationale of using and developing new cosmetic products that reduced the impact of pollution upon some hair properties.

Shelf-Life Evaluation of Pork Loins as Influenced by the Application of Different Antimicrobial Interventions.

The objective of the study was to determine the impact of antimicrobial interventions and refrigerated dark storage on the shelf-life of pork chops. Boneless pork loins (n = 36) were split and stored for 1, 14, 28, and 42 days at 2-4 °C after being treated with the following antimicrobials: water (WAT), Bovibrom 225 ppm (BB225), Bovibrom 500 ppm (BB500), Fit Fresh 3 ppm (FF3), or washing solution 750 ppm (WS750). After the end of dark storage, pork loins were further processed and sliced into chops, overwrapped in trays, and displayed for up to an additional 96 h in a retail case. Instrumental and visual color measurements as well as mesophilic and psychrotrophic aerobic bacteria, and lactic acid bacteria were measured. BB500 and FF3 performed better in inhibiting the growth of indicator bacteria under 6 logs; however, FF3 presented the best stability for color during storage. Principal component analysis clustered initial dark storage days with a* and chroma while % discoloration, hue, b* and microorganisms where clustered with longer dark storage times. In general, treatment FF3 presented the best performance, both in inhibiting microbial growth and maintaining the stability of color, thus increasing the shelf-life of pork loins.

Physicochemical characterization and consumer preference of rice (Oryza sativa) varieties grown in Costa Rica

Introduction: Rice is a staple food in Costa Rica representing almost 24 % of the total calorie intake in the diet. Consumers have become more quality conscious about the rice consumed, so producers need to focus on the quality of rice along with production. Objective: The aim of this study was to investigate the physicochemical profile and consumer preference of five Costa Rican rice varieties: Palmar 18, Basmatico, Chin Chin, INTA-Miravalles, and CR- 5272. Materials and methods: Proximate analysis, amylose, and mineral content were performed in the raw grain. Two different sessions were performed (n=120 each) to evaluate consumer preference measurements using the John Brown R-Index (RJB) index. The first sensory panel selected the best cooking preparation and the second, the preferred rice variety. Instrumental color measurements (L*, C*, hº, DE) were applied to the cooked rice varieties (76-96ºC for 38 min). Results: Regarding the physicochemical characterization, INTAMiravalles showed the highest protein content (8.2%), while Basmatico and Chin Chin, the lowest. Four varieties presented high amylose content (AC) and INTA-Miravalles reported an intermediate AC. The mineral content varied among varieties. INTA-Miravalles showed the highest N, followed by Palmar 18. The cooking preparation from the regulatory agency was preferred by consumers. The consumers’ preference of the varieties ranked from high to low: Basmatico&gt;Chin Chin=CR5772&gt;Palmar 18=INTA-Miravalles. Conclusions: This study suggests that consumer preference for cooked rice was influenced by physicochemical characteristics such as protein, AC, mineral content, and aromatic attributes. Consumer acceptance is an important factor to consider when new varieties are developed. The water-to-rice ratio during cooking played an important role in cooked rice sensory quality.

Interrelationships Between Visual and Instrumental Measures of Ground Beef Color

Two experiments were conducted to understand the interrelationship among visual color score, Farnsworth-Munsell values, instrumental meat color measurements, and their impact on beef color evaluation. In experiment 1, L*, a*, and b* values and various reflectance traits of the Farnsworth-Munsell 100-Hue Test tiles were measured.Incremental changes of the tiles were used to predict changes in a* values and other color variables that can be seen by a trained visual panel. Regression analysis suggests that trained panelists that pass the Farnsworth-Munsell Hue Test can discriminate a change of 0.95 in a*, 0.9 in b*, and 2.54 in hue angle values when Illuminant A is used. In experiment 2, ground beef was assigned randomly to one of 36 combinations of 3 storage temperatures, 4 storage times, and 3 display temperatures to create a variety of surface colors. A 10% change in ground beef metmyoglobin content corresponded to 3.2 units of a* (R2=0.95). Of all the instrumental measurements, a* (r=−0.97) and chroma (r=−0.97) best represented the red color intensity that panelists saw on the surface of ground beef. Significant surface discoloration occurred at 37.1% metmyoglobin and an a* value of 25.4 (with Illuminant A). Using a 5-point visual lean color scale,the change required in a* value for a unit change visual color score was 4.6. In conclusion, a* and chroma are highly related to visual color scores and changes in metmyoglobin, and a change in a* of 0.95 can be observed by visual panelists that have passed the Farnsworth-Munsell test.

A meta-analysis of the effect of gamma irradiation on chicken meat quality: Microbiology and colour

A meta-analysis of the effect of gamma irradiation on the microbial status and colour in raw chicken meat was performed. A total of 14 studies were selected and data about the total viable count (TVC), coliforms (TCC), instrumental colour measurements - lightness (L*), redness (a*) and yellowness (b*) was extracted for evaluation in gamma treated and untreated meat. Due to the high between study heterogeneity, the meta-analysis was conducted through random-effects model applied on the raw mean difference (effect size) for each outcome of interest. The results of the meta-analysis showed that gamma irradiation considerably decreased TVC and TCC (P&lt;0.001). Gamma rays also significantly diminished L* (P=0.013), but increased a* and b* (P&lt;0.001). The meta-regression models showed that the dose of the radiation contributed to the overall effect of irradiation TVC (P=0.006), TCC (P=0.074) and a*(P=0.007). The effect of gamma rays on TVC was further influenced by storage (P=0.007), while package affected the increase of a* (P=0.100).

Frankfurter-Type Sausage Enriched with Buckwheat By-Product as a Source of Bioactive Compounds.

Buckwheat by-products may be used as promising food ingredients due to their nutritional composition. Buckwheat husk (BH) may be used in meat products as a source of valuable compounds. In this study, the addition of BH to the quality of frankfurter-type sausages was investigated, aiming to reduce buckwheat waste and to develop nutritionally enriched sausages. For the purpose of this study, a range of measurements, as well as observations, have been carried out. This included the following: pH, weight losses, yield, the instrumental color and texture measurement, protein digestibility, polyphenols, amino acid, trace elements analysis, and the organoleptic evaluation. Compared with no BH sausages, the cooking losses of sausages with 3% BH were higher, while storage losses were lower. BH increased the hardness of sausages after two weeks of storage. The growing addition of BH resulted in a decrease in L* and b*. This change of color resulted in its lower level of consumer acceptability. BH addition did not reduce the protein digestibility. The total amino acid content increased with the increasing husk addition, from 161.8 mg/kg to 228.0 mg/kg. Moreover, BH increased the content of manganese, calcium, potassium and magnesium. This research suggested that incorporation of BH improved the nutritional value of sausages with minimal changes in technological and sensory properties.

Survival Analysis to Predict How Color Influences the Shelf Life of Strawberry Leather.

Color change of fruit-based products during storage is an important quality parameter to determine their shelf life. In this study, a combination of relative humidity (RH) and illumination was evaluated on the stability of strawberry leathers. Samples were conditioned at 25 °C, in chambers with RH of 22.5% and 52.3% and under two levels of illumination (no illumination and with a light-emitting diode (LED) illumination at 1010 lx). Samples were analyzed during storage by instrumental color measurements, total anthocyanin content, and consumers’ acceptance/rejection of the product color. Current-status survival analysis was performed to estimate the sensory-based shelf-life of the strawberry leather. The chromatic parameters (a* and ΔE* values) and anthocyanin content changed with increasing storage time and RH, fitting a first-order fractional conversion model. Samples conditioned at the higher RH showed a higher reduction of a* values and anthocyanins losses when stored under LED illumination than those without illumination. The increase of RH resulted in a faster increase of the consumer rejection probability and a shorter shelf life of the strawberry leather. For 50% of consumers’ rejection, the sensory shelf life of the strawberry leather equilibrated at 22.5% RH was estimated as at least 54 days, while it was reduced to approximately 2 days at 52.3% RH. The red chromatic parameter (a* value) strongly correlated to the percentage of consumer rejection in all storage conditions, suggesting that this analytical parameter can be useful as a predictor of strawberry leather’s shelf life. Therefore, the results of this study show the applicability of an approach that integrates instrumental and sensory data to acquire faster information on color changes during the storage of strawberry leather and product shelf-life prediction.

Barevnost a obsah některých biologicky aktivních látek v medu

This paper highlights the correlations between instrumental measurements of colour and the content of some biologically active organic compounds (especially phenolics and flavonoids) in honey. Sufficiently close correlations may lead to the development of procedures for rapid determination of the content of these substances in honey by colour measurement without the need for more demanding sample preparation.