Differences In Color Parameters Research Articles

Color Characteristics of High Yttrium Oxide–Doped Monochrome and Multilayer Partially Stabilized Zirconia upon Different Sintering Parameters

Abstract Objectives Sintering influences the optical properties of zirconia. This study examined the effect of altering sintering temperature and time of monochrome (Mo) and multilayer (Mu) 5 mol% yttria-partially stabilized zirconia (5Y-PSZ) on color characteristics. Materials and Methods Three hundred specimens (width × length × thickness = 10 × 20 × 2 mm) were prepared from Mo and Mu (with cervical [C], middle [M], and incisal [I] region) 5Y-PSZ and randomly sintered at decreasing (Td: 1,450°C), regular (Tr: 1,500°C), and increasing (TI: 1,550°C) sintering temperature, with extremely short (He: 10 minutes), ultrashort (Hu: 15 minutes), short (Hs: 30 minutes), and regular (Hr: 135 minutes) sintering time (n = 15/group). Color appearance (EW ), translucency parameter (TP), contrast ratio (CR), opalescence parameter (OP), and color appearance difference (∆E diff) were evaluated in the CIE L*a*b* system. Microstructures were evaluated by scanning electron microscope (SEM) and X-ray diffractometer (XRD). Statistical Analysis Analysis of variance (ANOVA) and Bonferroni comparisons were determined for significant differences (p < 0.05). Results Significant differences in color parameters upon zirconia type, sintering temperature, and sintering time, and their interactions were indicated (p < 0.05). Increasing sintering temperature and extended sintered time resulted in larger grain, reduced tetragonal-to-monoclinic phase transformation, and significantly increased the TP and OP, but decreased the CR and ∆E diff (p < 0.05). Decreasing sintering temperature and time led to clinically unacceptable color appearance. Conclusion Mo was found to be more translucent than Mu. To achieve the most favorable optical properties, increasing sintering temperature and extending sintering time are recommended. Decreasing sintering temperature is not suggested. However, shortened sintering time is feasible, but it needs sintering with increasing sintering temperature to achieve a promising color appearance.

Comparative study on nutraceutical and sensorial characteristics of saffron (Crocus sativus L.) cultivated in Iran, Spain, and Türkiye.

Quality properties of 14 saffron samples from Iran, Spain, and Türkiye were compared. Significant differences were observed between anthocyanins, volatile compounds, fatty acids, total phenolic content, and antioxidant activity of saffron samples (P < 0.05). Besides, significant differences in color parameters were observed. Moreover, a total of 13 volatile compounds were identified in the saffron samples using. headspace-solid-phase microextraction-gas chromatography-mass spectrometry, safranal and α-isophorone being the two predominant aroma compounds. Regarding fatty acids, significant differences were seen in the fatty acid profiles of saffron samples (P < 0.05), while linoleic acid was the most concentrated fatty acid. In terms of sensory properties, different concentrations of safranal, α-isophorone and 4-ketoisophorone may lead to significant differences in the odor and taste attributes of saffron samples (P < 0.05). Changes in corm origin along with climate and agricultural conditions may affect the quality characteristics of saffron cultivated in different geographical areas to a significant degree. © 2024 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Enhancing Bifidobacterium and lactic acid bacteria activity, and improving oxidative stability in functional algal concentrated yoghurt with Spirulina platensis powder

The purpose of this study was to examine the growing demand for healthy functional dairy products by investigating the incorporation of Spirulina platensis into concentrated yoghurt and evaluating its impact on starter cultures and product properties. A comprehensive analysis demonstrated the potential of spirulina to enhance bifidobacteria growth, acidity, PUFA content, and antioxidant activity in yoghurts, indicating its potential to improve the nutritional quality and oxidative stability of dairy products. The study investigated the impact of different Spirulina ratios on the activity of yoghurt starter cultures, including Lb. casei, Lb. plantarum, Lb. acidophilus, and Bifidobacterium mix. Three concentrated yoghurt samples were prepared, including a control, a probiotic sample, and a sample incorporating Spirulina powder. The findings suggest that while Spirulina did not significantly affect lactic acid bacteria, it noticeably stimulated the growth of Bifidobacterium. Treated samples showed increased acidity and TVFAs, with pH values displaying an inverse trend compared to the control. Clear differences in colour parameters and sensory evaluations distinguished control from treated samples. Additionally, Spirulina supplementation demonstrated a pronounced effect in enhancing antioxidant activity, as observed through DPPH radical scavenging activity, and influencing the peroxide value, reflecting improved oxidative stability in the yoghurt. This successful utilisation of Spirulina suggests its potential application in diverse edible algae in the food sector, especially in dairy products, enhancing both nutritional and sensory aspects, as well as contributing to improved oxidative stability

Color Analysis of Merkel Cell Carcinoma: A Comparative Study with Cherry Angiomas, Hemangiomas, Basal Cell Carcinomas, and Squamous Cell Carcinomas.

Merkel cell carcinoma (MCC) is recognized as one of the most malignant skin tumors. Its rarity might explain the limited exploration of digital color studies in this area. The objective of this study was to delineate color alterations in MCCs compared to benign lesions resembling MCC, such as cherry angiomas and hemangiomas, along with other non-melanoma skin cancer lesions like basal cell carcinoma (BCC) and squamous cell carcinoma (SCC), utilizing computer-aided digital color analysis. This was a retrospective study where clinical images of the color of the lesion and adjacent normal skin from 11 patients with primary MCC, 11 patients with cherry angiomas, 12 patients with hemangiomas, and 12 patients with BCC/SCC (totaling 46 patients) were analyzed using the RGB (red, green, and blue) and the CIE Lab color system. The Lab color system aided in estimating the Individual Typology Angle (ITA) change in the skin, and these results are documented in this study. It was demonstrated that the estimation of color components can assist in the differential diagnosis of these types of lesions because there were significant differences in color parameters between MCC and other categories of skin lesions such as hemangiomas, common skin carcinomas, and cherry hemangiomas. Significant differences in values were observed in the blue color of RGB (p = 0.003) and the b* parameter of Lab color (p < 0.0001) of MCC versus cherry angiomas. Similarly, the mean a* value of Merkel cell carcinoma (MCC) compared to basal cell carcinoma and squamous cell carcinoma showed a statistically significant difference (p < 0.0001). Larger prospective studies are warranted to further validate the clinical application of these findings.

Evaluation of low sodium Kačkavalj cheese properties using 3D scanning, scanning electron microscopy and computer vision system

Salt reduction in food is one of the main concerns for public health agencies. Performing two‐way analysis of variance, the effects of salt reduction and replacement on the pasta filata Kačkavalj cheese properties were studied during 6 months. Computer vision system is a novel method for colour evaluation. There were no differences in colour parameters L*, a* and b* (90.40–92.87, 0.07–0.60 and 11.40–18.53 respectively) and microstructure analysed by scanning electron microscopy between variants during ripening. Three‐dimensional scanning revealed that low sodium variants showed lower volume reduction. Salt reduction in Kačkavalj cheese results in high quality product and contributes to consumer health.

Protection of antioxidant components and production of a natural food colourant powder from Ardisia compressa juice

Ardisia compressa Kunth fruit juice is rich in bioactive compounds with proven health benefits and a characteristic intense purple colour. In this investigation the effect of the wall material (using soy protein isolate (SPI) and whey protein isolate (WPI)) and type of microencapsulation (spray drying (SD) and freeze-drying techniques (FD)) on the physicochemical properties, antioxidant properties and stability in different conditions storage of the microcapsules of the juice of Ardisia compressa Kunth was evaluated. The results obtained showed that the powders developed by FD and SD exhibited differences in colour parameters, as well as physicochemical and antioxidant properties. SPI and WPI powders obtained by FD exhibited higher retention of colour, polyphenols and antioxidant activity after the drying process and during storage. Stability tests revealed that the samples obtained presented first-order degradation of polyphenols and zero-order degradation of colour, and the conditions of greatest stability were found at low water activities (0.1–0.3) at a temperature of 25 °C. The microcapsules exhibited variable morphology depending on the production technique. In conclusion, freeze-drying, using WPI and SPI as wall material, improve stability to colour, polyphenols and antioxidant activity to microcapsules produced with Ardisia compressa juice, demonstrating potential for application as a natural colourant or functional additive.

Comparison of the effects of extraction method and solvents on biological activities of phytochemicals from selected violet and blue pigmented flowers

The flowers of many plant species are characterized by intense color and richness of bioactive compounds. They can be their valuable and curious sources that are worth extracting with the highest possible efficiency. The study compares the effects of different extraction methods and ultrasound (US) treatment on the physicochemical properties of dried petals of Malva sylvestris (MS), Clitoria ternatea (CT), Centaurea cyanus (CC), and Trifolium pratense (TP). The petals were ground and then extracted by three methods: (1) with H2O, (2) with 70% methanol, (3) with 70% methanol + acetic acid solvents, additionally used US. Measured: color parameters in CIEL*a*b* system; total antioxidant activity (TAA) referred to the 1,1-diphenyl-2-picrylhydrazyl (DPPH) and 2,2’-azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) (ABTS) radicals activity; total phenolic content (TPC) by the Folin-Ciocâlteu method; total anthocyanin content (TAC) by the pH differential method. No specific differences in color parameters founded. The highest TAA (in % of DPPH reductive- MS: 87.86; CT: 62.56; CC: 72.04; TP: 82.99), TPC (in mg gallic acid equivalent/100 g of sample- MS: 1072.86; CT: 849.85; CC: 912.07; TP: 873.77), and TAC (in mg of cyanidin-3-glucoside/100 g of sample- MS: 747.79; CT: 226.46; CC: 267.53; TP: 234.77) was reached by method (3). US treatment increased the effect.

Caracteristics of sunscreen from seaweed porridge (Turbinaria conoides) and galangal extract (Alpinia galangal)

Natural ingredients that have sunscreen activity, namely galangal (Alpinia galanga) have a role in absorbing UV rays. Seaweed (Turbinaria. conoides) contains alkaloids, tannins, antioxidants, fucoxanthin. Many cases of skin damage due to harmful cosmetic ingredients and exposure to UV rays have encouraged the authors to explore the natural wealth of seaweed and galangal into skin care products. The aim of the study was to determine the optimum formulation and evaluate the best characteristics of seaweed and galangal sunscreen cream preparations. This research was experimental with four treatments and three replications giving concentrations of seaweed and galangal F0 (control), F1(1:1), F2(1:2), F3(2:1). The tests carried out included hedonic, homogeneity, centrifugal, viscosity, SPF, humidity and pH tests. The hedonic results show significant differences in color parameters (F3). All treatments produced cream type (O/W) and were homogeneous, there was no phase change in the centrifugal test. The viscosity and pH values meet the requirements and can moisturize, the highest SPF value (F2) is 3.67 in the minimum category. The more addition of seaweed affects the color characteristics. The more galangal added, the higher the SPF. Of all the treatments, the formulation with the addition of seaweed and galangal affected the characteristics of the resulting cream.

Effect of infrared drying on chemical and microbial properties of Cold-Hardy grape pomace (Edelweiss and Marquette).

This study aims to add value to a common wine industry waste by preserving bioactive compounds in cold-hardy grape pomace (GP) and preventing any microbial growth under the proper drying conditions. Effects of infrared (IR) and hot air (HA) drying on the microbial and physicochemical properties such as color, phenolic compounds, and antioxidant activity of white (Edelweiss) and red (Marquette) GP were studied. The IR heating rapidly reduced the moisture content of GP from 55% wet basis (w.b.) to less than 10%, which resulted in a drying time reduction of 71.9% to 80.2% compared to HA drying. There were no significant differences in color parameters among the IR- and HA-dried pomaces (p > .05). The phenolic content of 'Edelweiss' pomace was not significantly affected by both IR and HA drying, whereas the phenolic content of 'Marquette' pomace was substantially reduced from 274 mg/g dry extract in raw pomace to 127 mg/g dry extract after HA drying and to 141.9mg/g dry extract after IR drying. Overall, the microbial load on the fresh pomace samples was dramatically reduced by IR heating, with a reduction of more than 99.9% when the pomaces were dried using IR at a temperature higher than 130°C. However, this high temperature of IR led to a significant reduction of DPPH antiradical scavenge activity for 'Edelweiss' pomace (p < .05). This study shows that using the IR approach, cold-hardy 'Edelweiss' and 'Marquette' grape pomaces can be efficiently dried with the antioxidant activity maintained, which could be used in a variety of food products as a functional ingredient.

Consumer perception and physicochemical characterization of a new product made from lactic acid fermented orange peels

A new product made from orange peels discarded from juice making has been characterized during the present study. In order to reduce its bitterness, orange peel was fermented during 10 days in two different sugary brines (2% or 5% NaCl content) using a Lactiplantibacillus plantarum strain. The lactic acid fermentation process was characterized by determining pH, sucrose, and the organic acids content. The original peel and the final products were characterized by instrumental texture and color determination, and total flavonoids content. In addition, consumers' expectations and perception of the new products were also studied using an online survey and a consumer study in which acceptance and perceived bitterness were assessed. Results suggested that the 2% NaCl-fermentation process allowed a greater bacteria development (with a higher lactic acid production and larger differences in color parameters with the original peel than the 5% NaCl-fermented samples) although both fermented samples were significantly different from the original peel in their physicochemical characteristics. Total flavonoids content, which has been related to bitterness perception, was significatively lower in the fermented samples than in the raw orange peel (50% reduction). Spanish consumers’ expectations and perception of the new product were similar, and the snack made with the peel fermented in the 2% NaCl-brine was more liked than the same snack made with the original peel, or the 5% NaCl-fermented one. Using a lactic acid fermentation in a sugary brine was useful to decrease the bitterness perception and increase liking of the orange peel, meaning a potential valorization for this orange juice by-product.Implications for gastronomy.The present study includes the physico-chemical characterization and consumers’ perception of a new product developed with one of the main citrus by-products: orange peels. A new ingredient for the Spanish gastronomy is proposed, showing a potential use for one of the main HORECA (HOtels REstaurants Catering sector) and juices industry by-products. A simple lactic-acid fermentation process, inspired in the North-African gastronomy culture, is described, and the consumer perception of the new product, presented as a freeze-dried snack is shown, proposing a new way of decreasing this food waste in Spain. In addition, some ideas about how to decrease bitterness perception on flavonoids-rich materials are shown, contributing to the knowledge on other new foods development.

Comparative Study of Sensory Attributes of Leafy Green Vegetables Grown Under Organic and Conventional Management

This study was carried out to compare the sensory qualities of leafy green vegetables (collard, kale, lettuce and swiss chard) grown under organic and conventional production systems. Four leafy greens were produced on an organically and conventionally managed research farm of Tennessee State University, Nashville, TN in Spring 2019 and 2020. Crops in a conventional field were grown in the open field, whereas in organic field crops were grown in the open and under three different row covers (agribon cloth, insect net and plastic). Row covers in organic systems were used to protect crops from insect damage. Plant samples were collected from all the treatments and evaluated for sensory qualities including color, texture, taste, odor and flavor following two approaches i.e., instrumental and via consumer panel perception. Consumer panel perception results showed minor differences in the sensory qualities between organic and inorganically produced leafy greens. Instrumental methods showed no differences in color parameters of kale, lettuce and swiss chard grown under organic and conventional production systems. In collard, the lightness (L*), b* (yellow-blue axis), brightness (Y) and chroma (C) values were higher in conventional, while hue angle was higher in organic (open). There were no differences in instrumental textural values of organically and conventionally grown leafy greens. Among row covers, the textural value of collard and kale was higher in open relative to row covers. The content of main quality contributors 1-Hexanol was higher in conventionally grown collard compared to organic (open). Aldehyde compound was higher in organically grown kale and trans-hex-2-enyl-acetate (Ester) compound was higher in conventionally grown kale. Monoterpenes were higher in organic lettuce and ketones were higher in conventionally grown lettuce. Overall, there were not many differences in the sensory qualities of leafy greens grown under organic and conventional production systems. Further comparative studies between organic and conventional systems on sensory qualities of leafy greens are needed.

Characteristics of Dough Rheology and the Structural, Mechanical, and Sensory Properties of Sponge Cakes with Sweeteners.

Changes in the rheological properties of dough, as well as the microstructural, mechanical, and sensory properties of sponge cakes, as a function of the substitution of sucrose in a formulation with maltitol, erythritol, and trehalose are described. Moreover, the relationship between the examined properties was investigated. The replacement of sucrose with maltitol or trehalose did not affect the consistency index, whereas erythritol caused a decrease in its value. X-ray tomography was used to obtain the 2D and 3D microstructures of sponge cakes. All studied sweeteners caused the sponge cakes to have a typical porous structure. Erythritol and maltitol resulted in about 50% of the pores being smaller than 0.019 mm2 and 50% of the pores being larger than 0.032 mm2. Trehalose resulted in a homogeneous microstructure, 98% of whose pores were similar in size (0.019 to 0.032 mm2). The sponge cakes with polyols had a higher structure index than did the trehalose and sucrose samples. There were also significant differences in color parameters (lightness and chromaticity). The crust of the sponge cake with sweeteners was lighter and had a less saturated color than the crust of the sponge cake with sucrose. The sponge cake with maltitol was the most similar to the sponge cake with sucrose, mainly due to the mechanical and sensory properties. Trehalose led to the samples having high adhesiveness, which may limit its application as a sucrose substitute in sponge cake. Sensory properties were strongly correlated to cohesiveness, adhesiveness, and springiness and did not correlate to the 2D and 3D microstructures. It was found that 100% replacement of sucrose allows for a porous structure to be obtained. These results confirm that it is not the structure, but most of all the flavor, that determines the sensory perception of the sponge cakes.

Biological parameters, discolouration and radiopacity of calcium silicate‐based materials in a simulated model of partial pulpotomy

To analyse the discolouration, radiopacity, pH and calcium ion release of Biodentine (BD), Bio-C repair (BCR) and Bio-C temp (BCT), as well as their biological effects on human dental pulp cells (hDPCs). Sixty-four extracted bovine incisors were prepared to simulate crown fractures with pulp exposure and open root apex. The roots were filled using a mixture of agar and blood (control), and BD, BCR or BCT were placed over this mixture. Colour assessment analyses of the samples were performed before and immediately after material insertion and repeated at 30 and 90days, using a spectrophotometer. The colour change of each specimen was evaluated at the crown and calculated based on the CIELab colour space. Digital radiographs were acquired for radiopacity analysis. hDPCs were placed in contact with different dilutions of culture media previously exposed to such materials and tested for cell viability using the MTT assay. The pH and calcium ion release of all materials were measured after 24h; the data were assessed using one-way analysis of variance (ANOVA). Cell viability was analysed by two-way ANOVA. Differences in colour parameters and wound-healing data were assessed by two-way repeated measures ANOVA (α=0.05). Tukey's and Dunnett's tests were used to compare the experimental groups with the control group. BCR had grater radiopacity and smaller colour alteration (ΔEab/ΔE00) than the other materials tested (p<.005; p<.001). No significant differences in pH were found amongst the tested materials (p>.05). BCT was associated with the largest release of calcium ions (p<.0001). BD had cell viability similar to that of the control at the lowest dilutions, and BCR was similar to that of the control, regardless of the dilution tested (p>.05). BCT had a lower percentage of viability than that of the control at all tested dilutions (p<.0001). Cell migration rates in BD and BCR were similar to those in the control group after 24h and 48h (p>.05), whilst BCT had larger voids than the control in both periods (p<.0001). BCR, BCT and BD were associated with tooth discolouration. BCR had the lowest staining values, the highest radiopacity and viability greater than 80% hDPCs.

A laboratory evaluation of cell viability, radiopacity and tooth discoloration induced by regenerative endodontic materials.

To analyse the cytotoxicity, colour change and radiopacity of MTA Flow (MTA), UltraCal XS (UC) and Bio-C Temp (BT). Human dental pulp cells (hDPCs) stimulated with lipopolysaccharide (LPS) were placed in contact with several dilutions of culture media previously exposed to the experimental materials and tested for cell viability using MTT. Bovine teeth were prepared to simulate an open apex and to mimic extensive crown fracture. The roots were filled with a mixture of agar and blood, and the materials placed over this mixture. The control group consisted of teeth filled only with agar and blood. Colour assessment analyses were performed before and immediately after material insertion and repeated at 30, 45 and 60days using a spectrophotometer. The total colour change (ΔEab , ΔE00 and whiteness index (WI)) was calculated based on the CIELAB colour space. Digital radiographs were acquired for radiopacity analysis. Cell viability was analysed by one-way anova, whilst differences in colour parameters (ΔEab , ΔE00 and WI) were assessed by two-way repeated measures anova (α=0.05). Tukey's test was used to compare the experimental groups, and Dunnett's test was used to compare the experimental groups with the control group. MTA, UC and BT had similar cell viability to that of the control group (DMEM) (P>0.05), except for the BT group at the 1:1 and 1:2 dilutions, which had significantly lower viability (P<0.001). All materials were associated with discoloration values greater than what is considered to be the acceptable threshold, and BT resulted in less or similar tooth colour change than MTA and UC, respectively. Decreasing radiopacity over time was observed only in the MTA group (P=0.007). Lower values of radiopacity were found in the BT group compared with the UC and MTA groups (P<0.001). The new bioceramic material (BT) had acceptable cell viability, similar to that of MTA and UC at the highest dilutions, and BT resulted in less tooth colour change than MTA and UC. Despite its lower radiopacity, BT was identified radiographically.

EFFECT OF THE POSTHARVEST PROCESSING METHOD ON THE BIOCHEMICAL COMPOSITION AND SENSORY ANALYSIS OF ARABICA COFFEE

ABSTRACT The objective of this work was to study the influence of two postharvest processing methods on the biochemical composition and sensory analysis of a Colombian specialty coffee. For this purpose, coffee beans (Coffea arabica) of the Castillo variety were collected and processed using the wet and semi-dry methods, and the drying process was conducted in a sun drier prototype with a plastic parabolic cover, with a maximum drying air temperature of 50 °C; green coffee beans were managed according to the official Specialty Coffee Association cupping protocol and roasted to a medium and dark degree. Physicochemical determinations (pH, color, titratable acidity, caffeine content, and chlorogenic acid quantification) in green coffee and roasted coffee beans were performed; the sensory analysis was performed by a panel of trained tasters. The wet and semi-dry processing methods resulted in differences in color parameters, pH values, and caffeine content. However, the titratable acidity, chlorogenic acid, and sensory evaluation did not have any difference; therefore, the type of coffee processing method used is not relevant to the final chemical properties of the roasted coffee (i.e., the Castillo variety) evaluated in this study; the coffee cup score is also not affected, and the post-fermentation washing process can be dispensed with.

Impact of Increasing Levels of Oxygen Consumption on the Evolution of Color, Phenolic, and Volatile Compounds of Nebbiolo Wines.

Since the end of the last century, many works have been carried out to verify the effect of controlled oxygen intake on the chemical and organoleptic characteristics of red wines. In spite of the large number of studies on this subject, oxygen remains a cutting-edge research topic in oenology. Oxygen consumption leads to complex and not univocal changes in wine composition, sometimes positive such as color stabilization, softening of mouthfeel, increase of aroma complexity. However, the variability of these effects, which depend both on the oxygenation conditions and the composition of the wine, require more efforts in this research field to effectively manage wine oxygen exposure. The present study is focused on the evolution of the chemical composition of four different Nebbiolo wines, each of them added with 4 different doses of oxygen (7, 14, 21, and 28 mg/L total intake) during the first month of storage. In this perspective, the evolution over time of wine color and polyphenols was studied. Acetaldehyde, glyceraldehyde and glyoxylic acid were quantified by HPLC. These compounds can play a role in wine aging creating condensed colored and stable products involving anthocyanins with or without tannins. Moreover, some volatile aldehydes correlated with oxidized olfactory notes, including methional and (E)-2-alkenals, have been quantified by GC-MS. Overall, during storage a decrease of color intensity, total and free anthocyanins and an increase in polymeric pigments (in particular the contribution to the red color of pigments not-bleachable by SO2 or dTAT%) and some minor aldehydes was observed. Nevertheless, the differences in color parameters between the samples with different doses of oxygen were modest. These evidences were in contrast with an evident and detectable increase of free acetaldehyde content at increasing doses of oxygen measured after 60 days of storage. The effect of oxygen on color and production of SO2 non-bleachable pigments during aging varies with wine composition, with Nebbiolo wines appearing not very reactive in this respect, probably due to their low content in anthocyanins and high content in tannins.

Quality evaluation and drying characteristics of mango cubes dried using low-pressure superheated steam, vacuum and hot air drying methods

Ripe mango cubes were dried using different methods to process shelf-stable, nutrient-rich and convenient snack. To develop nutritive dried mango cubes as snack (MCS) low-pressure superheated drying (LPSSD) was carried out at 60–80 °C at ∼10 kPa and its effect on quality parameters and on drying behavior were compared to vacuum drying (VD) and hot air drying (HAD). In MCS higher retention of ascorbic acid, β-carotene, total phenol content and antioxidant activity followed the order of LPSSD, VD and HAD. Differences in color parameters, rehydration ratio and activation energy were not significant in MCS dried using LPSSD and VD as compared to HAD. Page model was found to fit best to the experimental data. Higher moisture diffusivity and lower activation energy was obtained in MCS dried by VD, followed by LPSSD and HAD. But, the differences were not significant in the activation energy in between VD and LPSSD process. The appropriate drying conditions for retaining the quality of MCS were found to be at 70 °C using LPSSD and at 60 °C using VD and HAD.

Addition of wood chips in red wine during and after alcoholic fermentation: differences in color parameters, phenolic content and volatile composition

&lt;p style="text-align: justify;"&gt;&lt;span style="font-family: Times New Roman; font-size: medium;"&gt;The effect of the time of wood chip addition on phenolic content, color parameters and volatile composition of a red wine made by a native Greek variety (Agiorgitiko) was evaluated. For this purpose, chips from American, French, Slavonia oak and Acacia were added in the wine during and after fermentation. Various chemical parameters of wines were studied after one, two and three months of contact with chips. The results showed that &lt;/span&gt;&lt;span style="font-family: Times New Roman; font-size: medium;"&gt;the addition of oak chips during alcoholic fermentation did not favor ellagitannin extraction and the reactions involved in tannin condensation and anthocyanin stabilization. Moreover, wines fermented with wood chips contained higher contents of whiskey lactones, &lt;/span&gt;&lt;span style="font-family: Times New Roman; font-size: medium;"&gt;eugenol, ethyl vanillate and acetate esters while &lt;/span&gt;&lt;span style="font-family: Times New Roman; font-size: medium;"&gt;their ethyl ester content was lower compared with the wines where chip addition took place after fermentation. &lt;/span&gt;&lt;/p&gt;&lt;p style="text-align: justify;"&gt;&lt;strong&gt;&lt;span style="font-family: Times New Roman; font-size: medium;"&gt;Practical Application:&lt;/span&gt;&lt;/strong&gt;&lt;span style="font-family: Times New Roman; font-size: medium;"&gt; The outcomes of this study would be of practical interest to winemakers since they could improve the control over the wood extraction process. &lt;/span&gt;&lt;span style="font-family: Times New Roman; font-size: medium;"&gt;When chips are added after fermentation wines seem to have a greater ageing potential compared to the wines fermented with chips due to their higher ellagitannin content and enhanced condensation reactions. On the other hand, color stabilization and tannin polymerization occur faster when chips are added during fermentation resulting in shorter ageing periods suitable for early consumed wines. &lt;/span&gt;&lt;/p&gt;

A Study on Possibility of Clinical Application for Color Measurements of Shade Guides Using an Intraoral Digital Scanner.

To assess if color measurement with intraoral scanner correlates with digital colorimeter and to evaluate the possibility of application of a digital scanner for shade selection. The L*a*b* values of the five shade tabs (A1, A2, A3, A3.5, and A4) were obtained with an intraoral scanner (TRIOS Pod) and a colorimeter (ShadeEye). Both devices were calibrated according to the manufacturer's instructions before measurements. Color measurement values were compared with paired t-test, and a Pearson's correlation analysis was performed to evaluate the relationship of two methods. The L*a*b* values of the colorimeter were significantly different from those of the digital scanner (p < 0.001). The L* and b* values of both methods were strongly correlated with each other (both p < 0.05). The device repeatability in both methods were reported to be excellent (p < 0.05). Within the limitations of this study, color measurements with digital intraoral scanners and computer-assisted image analysis were in accordance with those of the colorimeter with respect to L* and b* values; however, all the coordinates of shade tabs were significantly different between two methods. The digital intraoral scanner may not be used as the primary method of color selection in clinical practices, considering significant differences in color parameters with colorimeter. The scanner's capability in shade selection should be further evaluated.

The role of enamel thickness and refractive index on human tooth colour

ObjectivesTo investigate the role of enamel thickness and refractive index (n) on tooth colour. MethodsThe colour and enamel thickness of fifteen extracted human central incisors were determined according to CIELab colour scale using spectrophotometer (Crystaleye) and swept-source optical coherence tomography (SS-OCT), respectively. Subsequently, labial enamel was trimmed by approximately 100μm, and the colour and remaining enamel thickness were investigated again. This cycle was repeated until dentin appeared. Enamel blocks were prepared from the same teeth and their n were obtained using SS-OCT. Multiple regression analysis was performed to reveal any effects of enamel thickness and n on colour difference (ΔE00) and differences in colour parameters with CIELCh and CIELab colour scales. ResultsMultiple regression analysis revealed that enamel thickness (p=0.02) and n of enamel (p<0.001) were statistically significant predictors of ΔE00 after complete enamel trimming. The n was also a significant predictor of ΔH’ (p=0.01). Enamel thickness and n were not statistically significant predictors of ΔL’, ΔC’, Δa* and Δb*. ConclusionsEnamel affected tooth colour, in which n was a statistically significant predictor for tooth colour change. Clinical significanceUnderstanding the role of enamel in tooth colour could contribute to development of aesthetic restorative materials that mimic the colour of natural tooth with minimal reduction of the existing enamel.