Yellow Pigment Research Articles

Effect of stocking density on gonadal development, pigmentation and survival of Carassius carassius (Crucian carp) in a biofloc system

The present study was carried out to investigate the optimum stocking density for gonadal development, pigmentation, and survival of Carassius carassius stocked at varying stocking densities under a biofloc-based system. C. carassius (25 ± 0.15 g) were randomly distributed in sixteen tanks, each with 250 L water at the stocking densities viz. 1 kg/m3, 2 kg/m3, 3 kg/m3, 4 kg/m3 (10, 20, 30 and 40 fish/250 L). The carbon‑nitrogen ratio of 15:1 was maintained using wheat flour as a carbon source. The best gonad performance in terms of absolute fecundity (4449.98 ± 115.636), relative fecundity (114.67 ± 2.770), GSI (5.62 ± 0.018 and 2.93 ± 0.014 for females & males respectively), and advanced maturation stages (vitellogenic oocytes and seminiferous tubules with spermatozoa) was observed in the density treatment having 20 fish/250 L. The skin carotenoid content showed an increasing trend with maximum content (8.11 ± 0.018 μg/g)) recorded for the fish stocked at 20/250 L. The scales of the fish from the same treatment presented a higher concentration of yellow orange pigments giving an overall golden hue to the scales while as the density and dispersion of melanophores increased with an increase in stocking density giving an overall darker coloration to the fish, indicating a stressful condition at higher stocking density. The survival rate of fish showed no significant difference (p≥0.05) between the various density groups. The results of this experiment elucidate that Carassius carassius could be cultured with better gonad performance, increased carotenoid content, and high survival at a stocking density of 2 kg/m3 in a biofloc system.

Bio-production and characterization of carotenoid yellow pigment from Kocuria sp. GMA and exploring its sustainable antioxidant, antimicrobial and antibiofilm properties

Bio-production and characterization of carotenoid yellow pigment from Kocuria sp. GMA and exploring its sustainable antioxidant, antimicrobial and antibiofilm properties

Isolation and Molecular Characterization of Pigment Producing Bacteria from Soil of Different Locality of Assam

Pigment is the most attractive attribute and integral part of human life. The source of the pigment used for different applications is chemically synthesised. However, pigment produced from natural sources (such as plants and microorganisms) can also be applied as a coloring agent. In addition to being colorants, many natural pigments are also fascinating bioactive substances with possible health benefits. Agrochemicals, food, medicine, pharmacology, cosmetics, and numerous other industries use these compounds. In this study, a total of 7 pigmented colonies were isolated from the soil samples of different areas of Assam. Out of 7 pigmented colonies, 3 colonies showed orange color and 4 colonies showed yellow color. Based on the similarity of growth pattern and high intensity of pigmentation one colony from each pigment was picked for further studies. The isolated orange and yellow pigments were denoted as S1 and S2, respectively. With the help of Bergey’s Manual of Determinative Bacteriology the isolated pigmented strains were preliminary identified based on their morphological, microscopic, and biochemical characteristics and after that 16S rRNA gene sequencing helped to identify the bacteria at the species level and the strains were identified as (S1) Micrococcus aloeverae ON377368 and (S2) Exiguobacterium aestuarii ON377409. The identified strains Micrococcus aloeverae and Exiguobacterium aestuarii showed a high pigment production rate at specific optimized conditions such as at temperature 37°C, pH 6, and NaCl concentrations at 1.5-2% and strains also showed a good characteristic growth pattern at a specific time interval. Therefore, the present study may be a helpful step towards the large-scale manufacture of pigments and the extraction, purification, and characterization of the pigment extracted from these strains will lead to provide a potent eco-friendly natural dye in the industrial sector.

Connecting Stories: Investigations of a Seventeenth-century Mercator Hand-painted Map

ABSTRACT A seventeenth-century hand-painted map entitled Walachia, Servia, Bulgaria, Romania, printed with the original copper plate engraved by Gerardus Mercator, was investigated using portable, non-invasive spectroscopic and imaging methods. X-ray fluorescence spectrometry, UV fluorescence imaging, and short-wave infrared hyperspectral imaging were correlated to characterize pigments, differences in materials, previous interventions, and specific types of degradation. The results showed evidence for the use of vermilion, red lead, a green copper-based pigment, a gray-blue cobalt-based pigment, a chromate-based yellow pigment, and gold leaf, and even inferred the possible use of black ferro-gallic ink, thus highlighting both original materials and the likely presence of at least one previous restoration from the nineteenth century. Hyperspectral imaging was able to discriminate the most significant coloring materials, while UV fluorescence imaging suggested the use of organic material, both as a coating for the gold leaf and as a component in the mixture to temper the vermilion and the green copper-based pigments.

Deletion of the polyketide synthase-encoding gene pks1 prevents melanization in the extremophilic fungus Cryomyces antarcticus.

Cryomyces antarcticus, a melanized cryptoendolithic fungus endemic to Antarctica, can tolerate environmental conditions as severe as those in space. Particularly, its ability to withstand ionizing radiation has been attributed to the presence of thick and highly melanized cell walls, which-according to a previous investigation-may contain both 1,8-dihydroxynaphthalene (DHN) and L-3,4 dihydroxyphenylalanine (L-DOPA) melanin. The genes putatively involved in the synthesis of DHN melanin were identified in the genome of C. antarcticus. Most important is capks1 encoding a non-reducing polyketide synthase (PKS) and being the ortholog of the functionally characterized kppks1 from the rock-inhabiting fungus Knufia petricola. The co-expression of CaPKS1 or KpPKS1 with a 4'-phosphopantetheinyl transferase in Saccharomyces cerevisiae resulted in the formation of a yellowish pigment, suggesting that CaPKS1 is the enzyme providing the precursor for DHN melanin. To dissect the composition and function of the melanin layer in the outer cell wall of C. antarcticus, non-melanized mutants were generated by CRISPR/Cas9-mediated genome editing. Notwithstanding its slow growth (up to months), three independent non-melanized Δcapks1 mutants were obtained. The mutants exhibited growth similar to the wild type and a light pinkish pigmentation, which is presumably due to carotenoids. Interestingly, visible light had an adverse effect on growth of both melanized wild-type and non-melanized Δcapks1 strains. Further evidence that light can pass the melanized cell walls derives from a mutant expressing a H2B-GFP fusion protein, which can be detected by fluorescence microscopy. In conclusion, the study reports on the first genetic manipulation of C. antarcticus, resulting in non-melanized mutants and demonstrating that the melanin is rather of the DHN type. These mutants will allow to elucidate the relevance of melanization for surviving extreme conditions found in the natural habitat as well as in space.

Integrative transcriptomics and metabolomics analysis provide insight into the formation of skin pigmentation diversity in Chinese soft-shelled turtle (Pelodiscus sinensis)

Chinese soft-shelled turtle (Pelodiscus sinensis) is an important freshwater breeding species in East and Southeast Asia. The most external differences among different strains are skin pigmentation and blotches, but the mechanism of their formation is unknown. To investigate the mechanism of skin pigmentation diversity in Chinese soft-shelled turtle, three unique phenotypes (Golden strain, Japanese strain and Qingxi black strain) were selected to observe the chromatophores, and the transcriptome and metabolome were compared. The results showed the presence of melanophores, xanthophores and iridophores in the skin of all three strains. However, there were differences in the composition and organelles of chromatophores. The upregulation of gene asip and elevated accumulation of glutathione and cysteine in Golden strain resulted in the production of pheomelanin, leading to yellow pigmentation in the skin. The upregulation of gene dct and elevated accumulation of indole-5, 6-quinone in Qingxi black strain resulted in the production of eumelanin, which made the skin appear black-brown. Japanese strain produced eumelanin and pheomelanin, however, the presence of melanosomes resulted in skin darkening and appeared dark green pigmentation. The white blotches of Gloden strain and Japanese strains were formed through increased production of iridophores, while the black blotches of Qingxi black strain were formed by inducing migration and apoptosis of melanophores within iridophores. In conclusion, the distinctive characteristics of the skin in three strains resulted from combination of melanin type, abundance of melanosomes and interaction between melanophores and iridophores. These results provided valuable reference for investigating the mechanisms underlying skin pigmentation diversity in Chinese soft-shelled turtle and other vertebrates.

Multicoating construction of BiVO4@SiO2 yellow pigment for enhanced thermal stability and acid resistance

Multicoating construction of BiVO4@SiO2 yellow pigment for enhanced thermal stability and acid resistance

Skin carotenoid scores and metabolic syndrome in a general Japanese population: the Hisayama study

BackgroundHigher vegetable intake is being promoted as an initiative to prevent lifestyle-related diseases. Carotenoids are yellow or red pigment components and are widely present in vegetables. Since ingested carotenoids accumulate in the skin, skin carotenoid levels are a quantitative indicator of vegetable intake. Recently, noninvasive optical sensors for assessing skin carotenoid levels were developed. We here examined the association between skin carotenoid scores measured using optical sensors and the presence of metabolic syndrome.MethodsA total of 1618 individuals (604 men and 1014 women) aged ≥ 40 years (mean age 63.1 years) participated in the study. Skin carotenoid scores were determined using a noninvasive optical sensor based on multiple spatially resolved reflectance spectroscopy. Metabolic syndrome was defined based on the Joint Scientific Statement criteria developed by six international scientific societies. Multivariable-adjusted logistic regression models were used.ResultsThe prevalence of metabolic syndrome was 31.3% (n = 506). A remarkably strong association was found between higher skin carotenoid scores and lower prevalence of metabolic syndrome after adjusting for confounders. The multivariable-adjusted odds ratio for the presence of metabolic syndrome in individuals with the highest quartile of skin carotenoid scores was 0.39 (95% confidence interval, 0.28–0.55) compared to those with the lowest quartile.ConclusionsOur findings suggest that higher skin carotenoid scores measured by non-invasive optimal sensors are significantly associated with a lower likelihood of having metabolic syndrome in the general Japanese population.

Effect of Different Fertilizer Types on Quality of Foxtail Millet under Low Nitrogen Conditions.

In order to clarify the effect of different fertilizers on foxtail millet quality under low nitrogen conditions, we used JGNo.21 and LZGNo.2 as experimental materials and set up five treatments, including non-fertilization, nitrogen, phosphorus, compound, and organic fertilizers, to study the regulation of different fertilizer types on agronomic traits, nutrient fractions, and pasting characteristics of foxtail millet under low nitrogen conditions. Compared with the control, all of the fertilizers improved the agronomic traits of JGNo.21 to a certain extent. Nitrogen and compound fertilizer treatments reduced the starch content of JGNo.21; the starch content was reduced by 0.55% and 0.07% under nitrogen and compound fertilizers treatments. Phosphorus and organic fertilizers increased starch content, and starch content increased by 0.50% and 0.56% under phosphorus and organic fertilizer treatments. The effect of each fertilizer treatment on protein content was completely opposite to that of starch; different fertilizer treatments reduced the fat content of JGNo.21 and increased the fiber content. Among them, nitrogen and phosphorus fertilizers increased the yellow pigment content; the yellow pigment content increased by 1.21% and 2.64% under nitrogen and phosphorus fertilizer treatments. Organic and compound fertilizers reduced the content of yellow pigment; the yellow pigment content was reduced by 3.36% and 2.79% under organic and compound fertilizer treatments. Nitrogen and organic fertilizers increased the fat content of LZGNo.2; the fat content increased by 2.62% and 1.98% under nitrogen, organic fertilizer treatment. Compound and phosphorus fertilizer decreased the fat content; the fat content decreased by 2.16% and 2.90% under compound and phosphorus fertilizer treatment. Different fertilizer treatments reduced the cellulose and yellow pigment content of LZGNo.2. The content of essential, non-essential, and total amino acids of JGNo.21 was increased under compound and nitrogen fertilizer treatments and decreased under organic and phosphorus fertilizer treatments. The content of essential, non-essential, and total amino acids of LZGNo.2 was significantly higher under compound, nitrogen, and organic fertilizer treatments compared with control and significantly decreased under phosphorus fertilizer treatments. Nitrogen and compound fertilizer treatments significantly reduced the values of peak viscosity, trough viscosity, breakdown viscosity, final viscosity, setback viscosity, and pasting time of each index of JGNo.21; phosphorus and organic fertilizer treatments improved the values of each index. In contrast, the pasting viscosity of LZGNo.2 increased under phosphorus fertilizer treatment and decreased under nitrogen fertilizer treatment. Reasonable fertilization can improve the quality of foxtail millet, which provides a scientific theoretical basis for improving the quality of foxtail millet.

First Report of Leaf Rot Caused by Apiospora paraphaeosperma on Lily in Wuhan, China.

Lily (Lilium spp.) is a valuable ornamental bulb flower plant in Liliaceae, and its bulbs have high edible and medicinal value. Compared with bulb propagation of other lilies, seed propagation and short growth period are the most significant characteristics of Lilium×formolongi. In 2023, leaf rot disease (LRD) was observed on approximately 70% of the Lilium×formolongi seedlings sown in an experimental greenhouse in Wuhan, Hubei province, China. Irregular brown water-soaked spots were discovered in the early stages of infected seedlings. Then, spots spread throughout the leaves and caused the leaves to brown, soften, and wilted. A pathogen associated with symptoms was isolated by incubating sterilized leaves on potato dextrose agar plates at 25 ℃ for 2-3 days. Then, a pure single colony was isolated through a single hyphal tip isolation method. The fungal colony was white with abundant aerial mycelium and produced a yellow pigment diffusible into the agar. Microscopically, isolated mycelia were reticulate and pale yellow, while conidia were dark brown, smooth, and spherical, 7.31 to 6.98 × 4.03 to 3.87μm (average 5.44×5.41μm; n=30); oval in lateral view, and had a light stripe in the middle. To identify the species of the fungus at the molecular level, ITS and EF-1α genes were amplified and sequenced using primers ITS1/ITS4 (M Gardes et al. 1993) and 758F/986R (Carbone and Kohn 1999). The BLAST results in GenBank showed that the ITS(OR523578) and EF-1α(PP066842) sequences of LRD shared 99.82% and 99.24% identity with the distinct Apiospora paraphaeosperma strains (GenBank accession MT040110, ON806628.1, respectively). Combined with the morphology of the colony and conidium, the fungus was identified as Ap. paraphaeosperma. In the pathogenicity test, six healthy leaves were inoculated with mycelium disc and then kept in an incubator (22 ℃, 90% humidity, 16h light /8h darkness). The inoculated leaves showed necrosis and wilt symptoms similar to those observed in the greenhouse, while the control leaves were asymptomatic. A re-isolation, morphology identification and DNA sequencing of the fungus confirmed its infection with Ap. paraphaeosperma in Lilium spp. At present, rot caused by Ap. paraphaeosperma has only been reported in Thailand and South Korea, both of which are found on bamboo stems (Hyde et al. 2016; Sun Lul Kwon et al. 2022). As far as we know, this is the first report of leaf rot of lily caused by Ap. paraphaeosperma in China. This report can help identify this disease and further develop effective control measures.

Flower color modification in Torenia fournieri by genetic engineering of betacyanin pigments

BackgroundBetalains are reddish and yellow pigments that accumulate in a few plant species of the order Caryophyllales. These pigments have antioxidant and medicinal properties and can be used as functional foods. They also enhance resistance to stress or disease in crops. Several plant species belonging to other orders have been genetically engineered to express betalain pigments. Betalains can also be used for flower color modification in ornamental plants, as they confer vivid colors, like red and yellow. To date, betalain engineering to modify the color of Torenia fournieri—or wishbone flower—a popular ornamental plant, has not been attempted.ResultsWe report the production of purple-reddish-flowered torenia plants from the purple torenia cultivar “Crown Violet.” Three betalain-biosynthetic genes encoding CYP76AD1, dihydroxyphenylalanine (DOPA) 4,5-dioxygenase (DOD), and cyclo-DOPA 5-O-glucosyltransferase (5GT) were constitutively ectopically expressed under the cauliflower mosaic virus (CaMV) 35S promoter, and their expression was confirmed by quantitative real-time PCR (qRT-PCR) analysis. The color traits, measured by spectrophotometric colorimeter and spectral absorbance of fresh petal extracts, revealed a successful flower color modification from purple to reddish. Red pigmentation was also observed in whole plants. LC-DAD-MS and HPLC analyses confirmed that the additional accumulated pigments were betacyanins—mainly betanin (betanidin 5-O-glucoside) and, to a lesser extent, isobetanin (isobetanidin 5-O-glucoside). The five endogenous anthocyanins in torenia flower petals were also detected.ConclusionsThis study demonstrates the possibility of foreign betacyanin accumulation in addition to native pigments in torenia, a popular garden bedding plant. To our knowledge, this is the first report presenting engineered expression of betalain pigments in the family Linderniaceae. Genetic engineering of betalains would be valuable in increasing the flower color variation in future breeding programs for torenia.

The potency of yellow pigment extract from the marine bacterium Pseudomonas oryzihabitans SAB E-3 as an antioxidant agent

Abstract. Putri DA, Astuti RI, Wahyudi AT. 2024. The potency of yellow pigment extract from the marine bacterium Pseudomonas oryzihabitans SAB E-3 as an antioxidant agent. Biodiversitas 25: 2565-2575. Metabolic processes in cells can produce byproducts in the form of Reactive Oxygen Species (ROS). Excessive amounts of ROS are one of the causes of oxidative stress. Antioxidants are known to act as free radical-scavenging compounds. Pigment-producing bacteria associated with sponges have been widely reported to have antioxidant compounds. In this study, the marine bacterium Pseudomonas oryzihabitans SAB E-3 produced intracellular yellow pigments with potential antioxidant activity. Therefore, this study aimed to assess the in vitro antioxidant and mitochondrial activity at the cellular level and identify chemical compounds. The intracellular pigments produced by P. oryzihabitans SAB E-3 were extracted using methanol, acetone, chloroform, and ethyl acetate. The methanol pigment extract contained the highest number of phenolic and flavonoid compounds, which may have contributed to its antioxidant activity. Furthermore, the active fraction obtained from the bioautographic TLC and harvested using preparative TLC had stronger antioxidant activity against DPPH radicals (75.71 µg/mL) than the crude pigment extract. However, the ABTS radical-reducing activity was lower (226.59 µg/mL) than the crude pigment extract. The maximum wavelength of the pigment extract was 453 nm, indicating the presence of carotenoids. In addition, the lowest concentration of the crude pigment extract (50 µg/mL) and selected active fractions (18.75 µg/mL) increased yeast Schizosaccharomyces pombe ARC039 tolerance to oxidative stress and induced mitochondrial activity. Active fraction one extract analyzed using LC-MS/MS contained piceatannol, resveratrol, isorhapontigenin, isoliquiritigenin, liquiritin, and 2-Omethylisohemigossylic acid lactone, which may contribute to its antioxidant activity. Therefore, the yellow pigment extract and the active fraction produced by P. oryzihabitans SAB E-3 are potential candidates for natural antioxidant sources.

Вміст пластидних пігментів у дерев сосни звичайної уражених сосновим вертуном в умовах Західного Полісся

The biosynthesis of plastid pigments in Pinus sylvestrys L.was investigated in pine trees affected by Melampsora pinitorqua in the conditions of the Western Polissya. The total content of chlorophylls and carotenoids in the needles of trees with a mild and moderate degree of damage by Melampsora pinitorqua is 13,3…30,0% lower than in the control. Trees severely affected by Melampsora pinitorqua synthesize 21.8...38.4% less green and yellow pigments. A decrease in the content of green pigments in experimental pine trees is caused by chlorophyll a. Іt influences on absorption direct sunlight for the process of photosynthesis. The ratio of chlorophylls a/b is close to the control in experimental trees with a mild and moderate degree of disease damage and decreases by 23.3...32.9% in trees with a severe degree of disease damage. Іn all affected trees, the ratio between the amount of green and yellow pigments is close to the control.

A multifunctional role for riboflavin in the yellow nectar of Capsicum baccatum and Capsicum pubescens.

A few Capsicum (pepper) species produce yellow-colored floral nectar, but the chemical identity and biological function of the yellow pigment are unknown. A combination of analytical biochemistry techniques was used to identify the pigment that gives Capsicum baccatum and Capsicum pubescens nectars their yellow color. Microbial growth assays, visual modeling, and honey bee preference tests for artificial nectars containing riboflavin were used to assess potential biological roles for the nectar pigment. High concentrations of riboflavin (vitamin B2) give the nectars their intense yellow color. Nectars containing riboflavin generate reactive oxygen species when exposed to light and reduce microbial growth. Visual modeling also indicates that the yellow color is highly conspicuous to bees within the context of the flower. Lastly, field experiments demonstrate that honey bees prefer artificial nectars containing riboflavin. Some Capsicum nectars contain a yellow-colored vitamin that appears to play roles in (1) limiting microbial growth, (2) the visual attraction of bees, and (3) as a reward to nectar-feeding flower visitors (potential pollinators), which is especially interesting since riboflavin is an essential nutrient for brood rearing in insects. These results cumulatively suggest that the riboflavin found in some Capsicum nectars has several functions.

Monascinol from Monascus pilosus-fermented rice exhibits hypolipidemic effects by regulating cholesterol and lipid metabolism

Monascinol (Msol), a novel yellow pigment produced in red mold rice (RMR) fermented by Monascus pilosus SWM-008, has a structure similar to monascin (MS), suggesting potential lipid-regulating properties. Therefore, this study investigated the hypolipidemic effects and mechanisms of Msol in a hyperlipidemic hamster model induced by a high-fat, high-cholesterol diet, comparing its efficacy to MS. The results demonstrated that Msol exerts a hypolipidemic effect by reducing the expression of fatty acid synthase (FASN) and sterol regulatory element-binding protein 2 (SREBP2) in the liver, while also increasing the excretion of triglycerides and bile acids in the feces of hyperlipidemic hamsters. Furthermore, we found that Msol surpasses the commonly observed red mold rice yellow pigment MS in AMPK phosphorylation. Additionally, Msol was more effective than MS in regulating triglyceride levels and alleviating inflammation. These findings position Msol as a promising new functional ingredient in RMR for hypolipidemic effects.

Ce doped (Y, Yb)3Al5O12 yellow cool pigment with high solar reflectance and enhanced colour performance

The high solar reflectance and good colour performance are requisite for the practical application of the colour-cool pigment. In this work, Ce-doped Yb3Al5O12 and (Y, Yb)3Al5O12 ceramic pigments were prepared by the sol-gel method. Both Ce3+ and Ce4+ ions coexist in the doped pigments. Due to the 4f→5d electron transition of Ce3+, the Ce-doped pigments have a selective absorption at around 400–520 nm, which is responsible for the yellow hue. The content of the Ce3+ ion determines the colour performance of the pigment. The size effect from the smaller Yb3+ ion results in an increased content of Ce3+ in the Ce-doped pigments, leading to an improved colour performance. The incorporation of Y3+ ion can effectively decrease the absorption at 975 nm, thereby enhancing the solar reflectance to 80.6 %, while maintaining good colour performance (Yb0.7Y2.1Ce0.2Al5O12, L* = 91.40, a* = -4.89, b* = 45.33). In a simulation experiment, the ceramic glaze coating based on the prepared pigment showed a temperature reduction of 5.2 °C compared to the commercial yellow pigment ceramic coating.

Leuconostoc gelidum Is the Major Species Responsible for the Spoilage of Cooked Sausage Packaged in a Modified Atmosphere, and Hop Extract Is the Best Inhibitor Tested.

Cooked sausages packaged in a modified atmosphere (MAP: 20% CO2, 70% N2, <0.2% O2) with evident yellow stains were analyzed. The aims of this work were to study the microbial cause of the spoilage and to evaluate different antimicrobial compounds to prevent it. Leuconostoc gelidum was identified as the primary cause of the yellow coating in spoiled cooked sausage, as confirmed by its intentional inoculation on slices of unspoiled sausage. Leuconostoc gelidum was the main bacteria responsible for the yellow coating in spoiled cooked sausage, as confirmed by its intentional inoculation on slices of unspoiled sausage. The yellow color was also evident during growth in the model system containing cooked sausage extract, but the colonies on MRS agar appeared white, demonstrating that the food substrate stimulated the production of the yellow pigment. The spoilage was also characterized by different volatile compounds, including ketones, ethanol, acetic acid, and ethyl acetate, found in the spoiled cooked sausage packages. These compounds explained the activity of Leuc. gelidum because they are typical of heterofermentative LAB, cultivated either on food substrates or in artificial broths. Leuc. gelidum also produced slight swelling in the spoiled packages. The efficacy of different antimicrobials was assessed in model systems composed of cooked sausage extract with the antimicrobials added at food product concentrations. The data showed that sodium lactate, sodium acetate, and a combination of sodium lactate and sodium diacetate could only slow the growth of the spoiler-they could not stop it from occurring. Conversely, hop extract inhibited Leuc. gelidum, showing a minimal inhibitory concentration (MIC) of approximately 0.008 mg CAE/mL in synthetic broth and 4 mg CAE/kg in cooked sausage slices. Adding hop extract at the MIC did not allow Leuc. gelidum growth and did not change the sensorial characteristics of the cooked sausages. To our knowledge, this is the first report of the antimicrobial activities of hop extracts against Leuc. gelidum either in vitro or in vivo.

Effects of fermentation on the structures of yellow compounds in citrus pomace

To enhance the stability and light resistance of the yellow compounds in citrus pomace, our study successfully isolated and purified five compounds using ultrasonic-assisted extraction and column chromatography. The identified compounds include methyl linoleate, (2-ethyl)hexyl phthalate, 1,3-distearoyl-2-oleoylglycerol, 6,6-ditetradecyl-6,7-dihydroxazepin-2(3H)-one, and n-octadeca-17-enoic acid. The monomers extracted from fresh pomace, compounds 1 and 2, exhibit structural similarities to flavonoids and carotenoids. In contrast, the polymers isolated from fermented pomace, compounds 3, 4, and 5, share structural units with the fresh pomace compounds, indicating the transformation to stable polymeric forms. This suggests that the microbial fermentation process not only enhances the value of citrus pomace, but also provides a promising pathway for the synthesis of natural antioxidant yellow pigments with far-reaching theoretical and practical significance.

Production, Extraction and Partial Characterization of Natural Pigments from Chryseobacterium sp. kr6 Growing on Feather Meal Biomass

Obtaining natural pigments from microorganisms is an alternative with high potential for biotechnological application. The use of agro-industrial wastes as substrate for cultivations enables a reduction of the production cost and may add value to potentially polluting byproducts. In this work, the extraction of pigments produced by the bacterium Chryseobacterium sp. strain kr6 was evaluated, employing feather meal as the sole carbon source for bacterial growth. The maximum production of the yellow pigments was observed for cultivation at 30 °C, during 48 h, with 5 g/L feather meal. The pigment extraction from the bacterial biomass was performed with the aid of physical methods and the testing of different organic solvents. The conditions that provided better extraction were using ultrasound with acetone as the solvent, reaching a yield of 180 μg/g biomass after optimization. The pigment was partially characterized via UV-visible, FTIR and mass spectroscopy and CIELAB color parameters, suggesting the presence of molecules belonging to the flexirubin group (aryl polyenes). The antioxidant capacity of the pigment was confirmed via the scavenging of DPPH radical and thiobarbituric acid reactive substances (TBARS) methodologies. Moreover, the pigment extract showed antimicrobial activity against Staphylococcus aureus and Enterococcus faecalis.

ГІДРОДИНАМІЧНІ ТА КІНЕТИЧНІ ЗАКОНОМІРНОСТІ ФІЛЬТРАЦІЙНОГО СУШІННЯ ЖОВТОГО ЗАЛІЗООКСИДНОГО ПІГМЕНТУ

The filtration drying method of the yellow iron oxide pigment has been proposed. The main characteristics of the stationary layer and the experimental results of the hydrodynamics of filtering the heat agent through the stationary layer of pigment of different heights have been presented, which allows us to conclude the application feasibility of the filtration method by taking into account insignificant values of pressure drops. The obtained kinetic regularities of the yellow iron oxide pigment filtration drying process at different heights of the material layer, pressure drops, and temperatures of the heat agent, make it possible to select, in a scientifically based way, the optimal parameters for the process implementation in the production conditions.