Chromatic Parameters Research Articles

Effects of drying methods on the characterization of fatty acids, bioactive compounds and antioxidant capacity in a thin layer of physalis (Physalis peruviana L.) pulp.

Physalis peruviana L. fruits are rich in bioactive compounds with health benefits. Processing of physalis into pulp with further dehydration has been proposed as a method to increase shelf life and preserve bioactive compounds. Here, the effect of three drying methods on the physico-chemical properties, color, antioxidant capacity, tocopherol and fatty acids content of physalis pulp thin layers were evaluated. The radical scavenging activity showed higher antioxidant activity at high temperatures rather than at low temperatures. Both, DPPH and ORAC assay showed a high antioxidant capacity of the physalis pulp. Chromatic parameters as well as Chroma and Hue angle were affected by drying temperature, which contributed to the discoloring of physalis pulp during this process. Based on these results, both convective drying and infrared drying at 80°C were proved to be viable drying options for physalis pulp.

Formulation and characterization of the quality parameters of jellies and candy pastes of purple pitanga (Eugenia uniflora L.) with reduced sugars

The objective of the present work was to characterize and microbiologically evaluate different formulations of jams and paste candies of purple pitanga with reduced sucrose contents. The formulations made for jams were “jam A” with a 100% proportion and “jam B” with a 50% proportion, all with the addition of pectin (1.5 g) and citric acid (0.45 g). For the paste candies the concentrations were “candy A” with 60% and “candy B” with 40%, all added with citric acid (0.6 g) and water (36 mL). The elaboration process followed all the quality control standards and, in sequence, the physicochemical (humidity; ash content; soluble solids; pH; titratable acidity; sugars; color parameters; anthocyanins; flavonoids) and microbiological (total and thermotolerant coliforms; molds and yeast; coagulase positive Staphylococcus and Salmonella sp.) characterizations were performed. The results of the analyses have been compare only between formulations of the same type of product. All physicochemical data were within the standard parameters for candies and jams. As for the color aspect, the samples showed a characteristic intense red, differing only in the chromaticity and luminosity parameters in sweets and jellies respectively. The pitanga by-products presented varied concentrations of bioactive compounds, with emphasis on greater amounts of anthocyanin. For all microbiological aspects evaluated, the results were in accordance with the standards established by the legislation. Thus, the possibility of the development of purple pitanga jams and candies has been showned, with a reduction in sucrose content, but with interesting nutritional, microbiological and visual characteristics.

Application of high pressure-assisted infusion treatment to mango pieces: Effect on quality properties

The aim of this study was to evaluate the effect of the high pressure-assisted infusion treatment on the quality properties of mango cubes. Factors studied were: sorbitol concentration (20°Brix, 40°Brix, 60°Brix), calcium lactate concentration (0%w/w, 1%w/w, 2% w/w) and pressure level (0.1 MPa, 300 MPa, 600 MPa). Results showed that process factors not only improved the mass transfer during the infusion process but also the solid gain was restricted by the incorporation of the calcium salt. The synergetic effect of pressure level and the addition of calcium salt preserved the mechanical properties. The tonality and chromaticity parameters of mango cubes were preserved by the antagonistic effect of the pressure level and sorbitol concentration. All microbiological counts were below the detection level. The most effective process was 600 MPa-60°Brix-2% w/w since it produced an 81.9% of inactivation of the polyphenol oxidase enzyme, which will allow preserving the final product. Industrial relevanceThe sensory and nutritional properties of fruit-based products are the main factor, determining the acceptance by consumers. During processing, these properties can be affected by different process factors, so there is a great interest in developing new processing methods that would enable the preservation of the quality properties of the fresh fruit. The present study showed that the application of the high pressure-assisted infusion process could be a promising alternative to preserve the quality of mango cubes. Therefore, based on the results, criteria for commercial production of high-quality mango cubes conserved in a sorbitol solution with adequate safety requirements could be established.

Quality evaluation of minimally fresh-cut processed pineapples

Physicochemical, sensory and microbiological quality parameters were determined in fresh-cut pineapple products. Containers with fresh-cut pineapple in cylinders or in chunks were considered and the above parameters were studied over ten days of storage at 5 ± 1 °C. Chromatic parameters presented differences between both formats, with the cylinders being more susceptible to browning. Besides, the cylinders had lower levels of acidity, texture and ascorbic acid, while in general, greater changes of the main quality physicochemical characteristics were observed in the ring format during the ten days of refrigerated storage. Liquid exudate increased, sucrose content decreased and a greater tendency to browning were observed during the cold storage at 5 ± 1 °C. Sensory characteristics and microbiological control for both types of format showed a positive evaluation after eight days of storage at 5 ± 1 °C. Mesophile, psychrophile, mold and yeast loads in both pineapple formats were relatively low (<106 CFU/g after 10 days under 5 °C for all the microbiological loads) throughout their useful shelf-life, taking into account that both formats were packed in trays in normal atmosphere without chemical treatment or any additives.

Partial replacement of fish oil with vegetal oils in commercial diets: The effect on the quality of gilthead seabream (Sparus aurata)

The long-term unsustainability of fish oil as a lipid source in aquaculture feeds has led to its progressive replacement with vegetable oils. Several studies have shown that this replacement results in a different fatty acid profile that is likely to compromise the healthy properties and quality of fish by reducing their n-3 HUFA content. In the present study, we evaluate the effect of partial replacement of fish oil with vegetable oils on the quality of the final product. Eighty-four gilthead seabream (Sparus aurata) were fed one of two different commercial diets for 19 weeks in triplicate (14 fish per tank). These diets contained either 100 % fish oil (FO diet) or a 75 % vegetable oil blend (VO diet) (50/50 mixture of soybean and rapeseed oil). After slaughter, physical-chemical analyses (Fatty Acids (FAs); flesh color; Water-Holding Capacity (WHC); pH; and Texture Profile Analysis (TPA)) and a sensory analysis were performed. Fish fed either diet displayed similar growth and feed conversion rates (SGR and FCR). The fish fed the VO diet showed an increase in muscular n-6 fatty acids, which resulted in a lower n-3/n-6 ratio. A lower presence of EPA and DHA fatty acids was also observed, although the total quantity of n-3 fatty acids was similar in both groups. With regard to fat quality, the Atherogenic Index (AI) was lower in the VO-diet group, while both groups presented a similar Thrombogenic Index (TI). The diet had some effect on quality parameters, but the changes were not very intense. The differences observed in the a* and b* chromatic parameters were not significant, but a greater and significant color saturation in the vegetable oil group was observed. No significant differences in pH and WHC were observed. Fish fed the vegetal oil diet also scored higher for hardness, springiness, gumminess and chewiness. In the sensory analysis no significant differences were observed between the two groups. The differences observed for both the fatty acid profile and the quality parameters do not appear to have any important implications in terms of either health or the sensory properties of gilthead seabream fed a vegetable oil diet.

Relationship between color and betalain content in different thermally treated beetroot products.

Several health benefits are currently attributed to natural pigments that give fruit and vegetables their inherently colorful properties. Color measurements might therefore serve as quick indicators of the potential health-promoting properties of such foods. Nevertheless, the relationship between color and pigment content depends on the type of matrix and pigment, as well as the factors affecting their interaction, which calls for further investigation. Hence, the aim of the present study is to investigate the relationship between color parameters and betalain content in three commonly consumed beetroot products (beetroot juice, beetroot puree and whole beetroot), subjected to thermal treatment. Our results showed a negative correlation between the total betalain content and the color parameters L*, a*, b*, chroma, and hue angle in beetroot juice, beetroot puree and whole beetroot. Two chromatic parameters, a* and chroma, are proposed as the best descriptors for the betalain concentrations of these products. Likewise, the tristimulus L/ab combination for the juice is also suggested as a good descriptor. Our findings highlighted that the relationship between color and total betalain content depended on the beetroot product under assessment, with the strongest correlations found for the juice. Squeezed beetroot was therefore suggested as an alternative to improve this relationship in more complex matrices such as whole cooked beetroots. Useful information from color determination sheds light on the relationship between color and betalain pigments in beetroot, suggesting that color determination could be used as an indicator of betalain content.

Chromaticity analysis of diffraction pattern of white light under the grating

From the D65 daylight source, the ten monochromatic lights were evenly selected to be mixed into white light. After grating diffraction, color mixing was performed by using the chromaticity method with the relative intensity as the proportionality factor. The mixed color and its chromaticity parameters at specific diffraction angle positions were obtained to calculate L*, a*, b* and dominant wavelength. The relationship between the parameters of the grating and the chromaticity parameters of the mixed color was studied separately. The results showed that the color of the white light diffraction pattern at the diffraction angle θ = 2° is most significantly affected by d, followed by N. There is well linear correlation between b and L*, a*, b* values; but the effect of b on the color is not obvious. Then the relationship between the light intensity of ten kinds of monochromatic lights and the grating constant according to the grating diffraction intensity equation were drew, and the “rainbow” phenomenon was found. Current method for calculating the average wavelength of mixed colors directly from the “rainbow” graph is verified to be equivalent to the chromaticity method.

Inclusion of AmazonianMauritia flexuosafruit pulp as functional feed in the diet for the juvenile Pacific white shrimpLitopenaeus vannamei

This study investigated the effects of the inclusion of Mauritia flexuosa fruit pulp in the diet on the growth performance, economic benefit, muscle composition, total contents of carotenoids and flavonoids, chromaticity parameters, total antioxidant capacity, and lipid peroxidation in the hepatopancreas and muscle of the juvenile shrimp Litopenaeus vannamei (weighing 1.26 ± 0.023 g). Five diets (37% protein, 10% lipid) consisting of 0 (control), 1.25%, 2.50%, 5.00% and 10.00% (w/w) M. flexuosa fruit pulp were formulated and provided to the shrimps (n = 50 per tank, treatments in triplicate) for 31 days. Results showed that there were no significant differences between the treatments in terms of the growth capacity, chromaticity parameters, muscle composition and total flavonoid content of shrimps (p > .05). However, the carotenoid content in the muscle and hepatopancreas of the shrimps was significantly increased due to the dietary carotenoids present in M. flexuosa fruit pulp (p < .05). This increase in the carotenoid content directly favoured the increase in the antioxidant capacity in the hepatopancreas and muscle of the shrimps (R² = 0.99 and R² = 0.97 respectively; p < .05). There was also a direct relationship between the carotenoid content and the decrease in lipid peroxidation in the hepatopancreas (R² = 0.90; p < .05). The feed cost kg⁻¹ in terms of weight gain and protein production decreased with the inclusion of high levels of M. flexuosa fruit pulp, reaching 8.11% and 18.76% of cost reduction, respectively, with the addition of 5.00% of M. flexuosa fruit pulp. Therefore, the inclusion of M. flexuosa fruit pulp in the diets of shrimp can increase the carotenoid content and the antioxidant capacity in the hepatopancreas and muscle, reduce lipid peroxidation in the hepatopancreas, and probably provide economic benefits for the rearing of juvenile shrimps.

Effects of two debittering processes on the alkaloid content and quality characteristics of lupin (Lupinus mutabilis Sweet).

The presence of quinolizidine alkaloids (QAs) in the species Lupinus mutabilis Sweet limits the expansion of its consumption and use, despite its high protein content. The objective of this research was therefore to determine the effect of two thermal treatments, aqueous (ATT) and saline (STT), on the QAs and total protein content, as well as on the texture (fracturability and hardness), visual perception attributes - hue (H*), luminosity (L*) and chromatism (C*) - and grain size in three lupin varieties (INIAP-450, INIAP-451, and Criollo). The water consumption required by each treatment was also measured. The debittering process with ATT helped to concentrate the total nitrogen by 560 g kg-1 and decreased the grain hardness to 2037 gf (grams of force) in the Criollo variety, while the chromatic parameters H* and C* increased in the three varieties. The STT treatment was more efficient than the ATT treatment in terms of the time required and the volume of water used to reduce the QAs to safe levels for consumption (2.5-3.5 g kg-1 ). The size of the grain increased to four times its original size; the luminosity L* decreased during cooking to a value of 41.49 in the Criollo variety and then increased to 57.42 during grain washing. The STT treatment is advisable for lupin debittering, although the extent of the effect was dependent on the variety. © 2020 Society of Chemical Industry.

Effect of high hydrostatic pressure on Salmonella spp inactivation and meat-quality of frozen chicken breast

The aim of this study was to evaluate the effect of the pressure level and holding time on the Salmonella spp inactivation during HHP processing in frozen chicken breast fillets. Once identified the most effective process, meat quality (color and texture) was evaluated. Results showed that the treatments at 500 MPa for 1 min and 400 MPa for 5 min were enough to guarantee Salmonella spp inactivation in frozen chicken breast fillets. With respect to quality parameters, an extension of shelf life is expected with both treatments, as counts of indigenous microbiota were below the detectable level (<2 logs CFU/g). However, chromatic parameters and texture profile of the fillets treated with HHP suffered significant changes. Even so, the treatment of 500 MPa for 1 min was more effective at preserving chromatic parameters than treatment of 400 MPa for 5 min. The texture profile between fillets treated was not significantly different.

High‐pressure processing of persimmon purée: Stability during chilled storage

The aim of the study was to evaluate the effect of the high pressure (HP) technology on the preservation of persimmon purée during chilled storage (1, 30, and 90 days at 4 ± 1 °C). Results showed that the treatment at 400 MPa for 1 min was enough to eliminate the microbial counts and no regrowth was observed during storage. Physicochemical parameters, phenolic compounds, and antioxidant capacity were not affected by HP and were kept stable during storage. The mechanical and rheological properties were not affected by HP treatments at 500 and 600 MPa, preserving these properties during storage. The HP treatments were not able to effectively preserve the chromatic parameters and achieve the complete inhibition of the enzyme´s activity. The conditions that achieved the best preservation of the quality properties was 600 MPa for 5 min. Practical applications The sensory and nutritional properties of fruits often determine the consumer choice of food. However, the quality properties of foods can be affected during processing and storage. High pressure (HP) technology has been used in different branches of the food industry. In the present study, the application of HP treatments has demonstrated to be a good alternative to preserve the natural characteristics of fruits, allowing the storage stability of the product for a long time. From this study, criteria for the commercial production of high-quality persimmon purée with safety requirements could be established.

EFFECTS OF ARTIFICIAL AGEING ON TEXTILES' PROPERTIES

In the present paper work it was evaluated the degradation degree of textile material after different types of exposure using micro-destructive methods such as: Scanning Electron Microscopy (SEM), stereomicroscope and Datacolor spectrophotometer. Thus, samples of cotton fabrics were exposed in three different methods: first – outdoors, to natural conditions, second – at a temperature of 60⁰C in an oven and third – buried in commercial plant soil in closed recipients. After 72 hours and 216 hour, specimens of the samples were taken and evaluated. Thereby, microscopic analyzes revealed that the cotton materials are more degraded after burial. The results obtained were correlated with chromatic parameters (DL*, DC*, DE*) and white degree (Berger and CIE). All the samples have color differences in comparison with the unexposed samples; they also present more saturated color and are darker. Cultural heritage represents our history, thus it is important to know how the environment works on textile materials and this way we can manage better the conservation requirements. Future studies will also be carried out on linen and woolfabrics.

The effect of the fishing season on the use value and physicochemical properties of the meat of selected fish species reared in Polish aquaculture

The objective of the research was to evaluate the impact of the fishing season on the value in use and physicochemical properties of the meat of selected fish species reared in Polish aquaculture. The study was conducted on five species: rainbow trout, common carp, grass carp, pike and tench. Fish were obtained from farms located in the Lublin Voivodeship in two seasons (spring/summer and autumn/winter). Morphometric measurements of the fish were performed, the percentage shares of body parts were assessed, and the physicochemical properties of the muscle tissue were measured: pH, electrical conductivity, water holding capacity, and CIE L*a*b* colour characteristics. The fishing season significantly affected the body weight of carp, rainbow trout and pike, the greatest body height of carp and rainbow trout, and the total length and head length of pike. Pike, grass carp and tench had significantly lower Fulton’s condition factors in the autumn/winter season than in the spring/summer season. The season significantly influenced the share of viscera in rainbow trout and grass carp, and that of fins in carp and rainbow trout. A significant impact of the season was also noted in the case of pH in rainbow trout and tench, electrical conductivity in trout, pike and tench, and the M/T ratio in grass carp and tench. Chromatic parameters differed significantly between seasons in pike (a*) and in carp and rainbow trout (b*).

Combined drying of Nopal pads ( Opuntia ficus‐indica ): Optimization of osmotic dehydration as a pretreatment before hot air drying

The aim of this work was to optimize the osmotic dehydration (OD) as a pretreatment before hot air drying (HAD) in Nopal pads. A Box–Behnken experimental design was used to optimize the OD conditions with respect to physicochemical and chromatic parameters, and mechanical properties of Nopal pads. Factors studied were: Three concentrations of sucrose (30, 40, and 50°Brix), calcium lactate (1, 2, and3%), and immersion time (1.5, 2.5, and 3.5 hr). Results showed that sucrose concentration and immersion time were the variables with higher influence. Quality properties mentioned before and the final mineral content of the dried samples (at 60°C for 48 hr) were analyzed. The combined drying (OD + HAD) reduced the moisture content in the range of 23% to 30% compared to HAD alone. It was found that the optimization of OD allowed preserving the quality properties, being a good alternative to give an added value for dried Nopal pads. Practical applications Nopal has important bioactive properties for both humans and animal diets, since it is a rich source of vitamins, minerals, and fibers. However, the main problem of its production is that post harvesting waste is greater than 50%. For this reason, there is a great interest to study inexpensive preservation methods that allow keeping the main attributes of processed fruits. The osmotic dehydration (OD) and the hot air drying (HAD) are two simple and inexpensive techniques which can be applied by both the food industry and small-scale food producers. In the present study, the optimization of OD as a pretreatment before HAD was a reliable tool to preserve the quality properties of Nopal pads.

Natural extracts from grape seed and stem by-products in combination with colloidal silver as alternative preservatives to SO2 for white wines: Effects on chemical composition and sensorial properties.

The search for alternative additives to sulfur dioxide, with antioxidant and antimicrobial activity, in the production of wines is one of the current objectives of the enological industry. In the present study, aqueous extracts obtained from winery byproducts (grape seeds and stems), alone or in combination with colloidal silver complex, have been used in white vinification. The antimicrobial effect of the extracts was similar to that of sulfur dioxide, being more effective on lactic and acetic bacteria in those wines to which colloidal silver was added. The effect on the color, the phenolic compounds and the volatile fraction of the wines was evaluated, as well as their sensory profile. The use of both extracts modified the color of the wines, increasing the chromatic parameters a* and b*, indicating a browning tendency, although no other signs of oxidation were found. Wines with seed extracts contained higher amounts of flavan-3-ols, and a significant increase in some volatile compounds such as fatty acid ethyl esters and benzene compounds, which were identified in the extracts. From a sensorial point of view, the wines with stem extracts were the most similar to those elaborated with SO2, detecting a certain bitterness in wines with seed extracts.

Quality, stability, carotenoids and chromatic parameters of commercial Sacha inchi oil originating from Peruvian cultivars.

Sacha inchi oil is a high-quality product with market potential and a wealth of bioactive compounds beneficial for food and health. The main objective of this work was to evaluate three quality parameters, stability, chromatic parameters and total carotenoids of commercial oils obtained from Sacha inchi seeds. The free acidity and peroxide value of all samples studied were in ranges of 0.16-1.86 (% α-linolenic acid) and 1.87-17.47 (meq O2/kg), respectively. While K232 value for the samples ranged from 1.96 to 2.29, the K270 value was between 0.08 to 0.20 and ∆K in the range of - 0.005 to 0.005. Regarding color, Sacha inchi oils showed high h ab and low values, and the L * values were from 91 to near 100 units. Samples were located in the second quadrant of the CIELAB a * b *-color diagram. These characteristics corresponds to low-vivid light-yellow colors. Carotenoid content of Sacha inchi oils was 0.31-9.10mg/kg. The oxidative stability using Rancimat (100°C, 20L/h air flow rate) of these oils presented an average value of 5.6h. Pearson's coefficients indicate a very high correlation coefficient between the values of Car (carotenoid) versus b * (yellow area) (r = 0.991). The results of this study provide better understanding of the quality, stability, chromatic intensities and carotenoid contents of Sacha inchi oil that is marketed in Peru.

Spraying ozonated water on Bobal grapevines: Effect on grape quality

Ozone is a powerful oxidant that is increasingly used as sanitizing agent in the wine industry and even in the vineyard to control grapevine diseases. In this study, we evaluated the effect on grape enological quality of ozonated water spraying treatments carried out in Bobal grapevines during two consecutive harvest seasons. In the first season, ozonated water was applied once during the ripening period on grapevines trained on the traditional gobelet system (S1). In the second season, ozonated water was applied three times between the fruit set and harvest on grapevines grown on a vertical trellis system (S2). Grape quality on harvest day was evaluated through several enological and chromatic parameters, the phenolic maturity, the Varietal Aroma Potential Index (IPAv) and the phenolic and volatile composition. The S1 treatment had a positive effect on the technological maturity, the chromatic parameters, the seed maturity and the content of glycosylated aroma precursors, phenolic compounds and free terpenoids of grapes. The S2 treatment also improved the technological maturity and the content of total anthocyanins (pH 1.0) and free terpenoids, but had a negative impact on the chromatic parameters, the anthocyanin extractability and the content of glycosylated aroma precursors and phenolic compounds. Therefore, ozonated water sprayed on Bobal grapevines affected the quality of grapes, but the effect seemed to depend on the number of applications.

Differential expression of anthocyanin biosynthetic genes in relation to anthocyanin accumulation in the pericarp of mango (Mangifera indica Linn.)

We evaluated 14 mango cultivars with different pericarp color for pigments, chromatic parameters and mRNA level of anthocyanin synthesis gene. Pericarp of anthocyanin concentration varied from none to 15.96/100g FW among the 14 cultivars, which were divided into three coloration types, i.e. non-red (Deshehari, white ivovy, Guire No.82, Guixiang, Lingshui, Qingpi and Yuexi No.1), medium type (Tainong No.1 and Chinhuang) and red (Renong No.2, Renong No.1, hongwacheng, Zillate, R2E2). From the results of expression of structure gene correlated with anthocyanin synthesis, the expression of the five genes, especially MiC4H, Mi4CL2, MiANS, MiDFR and MiUFGT2 in red cultivars were significantly higher than that of non-red cultivars.

Discrimination of flax cultivars based on visible diffusion reflectance spectra and colour parameters of whole seeds

Discrimination of yellow and brown seeded flax cultivars was made based on visible (Vis) diffusion reflectance spectra of whole seeds. Hierarchy cluster analysis (HCA) and principal component analysis (PCA) were used for the discrimination. Multivariate analyses of Vis spectra led to satisfactory discrimination of all flax cultivars of this study. The CIE L*a*b* colour parameters were calculated from the diffusion reflectance Vis spectra. The values of L* were in the range of 48.8–53.6 and 62.6–66.0% for brown and yellow seeded cultivars, respectively. Chromatic parameters a* and b* were in the range of 2.8–4.9 and 7.9–16.4%, respectively. A strong linear correlation (R&lt;sub&gt;2&lt;/sub&gt; = 0.9712) was found between a* and b* parameters for all the flaxseed samples. The L* and a* parameters were sufficient for HCA clustering of the individual flax cultivars.

COLOR CHANGES OF VARIOUS WOOD SPECIES IN RESPONSE TO MOISTURE

Color including texture and gloss is one of the most important esthetical attributes of wood. For any porous materials in contact with water, the phenomenon of surface darkening arises from a change in the refractive index, as water enters air-filled pores. For the first time, this research investigated to what extent MC differences affect the surface color, below fiber saturation and after the pores are filled with water, with respect to extractive contents. Samples from 13 wood species were exposed to various climates, and as soon as EMC was reached, the color was determined. Color changes were also recorded after water submersion and also after vacuum impregnation in water. Chromaticity parameters a* and b* widely increased, along with higher moisture contents. Lightness changesweremostly stable at lower moisture contents.An exceptionwas demonstrated by the heartwood species black locust, plum, walnut, and oak, which showed a brightening effect at lowermoisture contents, followed by the darkening phase. The overall darkening of wood at high RH is connected to capillary condensation. Liquid water present in the cell lumen most caused darkening and an intensification of hue (increase in a* and b*). Darkening was even more expressed after vacuum impregnation with water. In conclusion, with only limited fluctuations in moisture contents below fiber saturation, the expected color changes are minor to neglectabl