Effect of nonionic surfactant Brij 35 on morphology, cloud point, and pigment stability in Monascus extractive fermentation.

BACKGROUND: Nonionic surfactant Brij 35 in submerged fermentation of Monascus can significantly increase Monascus pigment yield. Here, the effects of nonionic surfactant Brij 35 on Monascus pigment secretion in extractive fermentation are discussed in terms of cell morphology, cloud point change, and pigment stability. RESULTS: At Brij 35 concentrations up to 32 g L-1 , the higher concentrations led to the loosening of the network structure on the surface of the fungal wall, enhanced cell wall permeability, and increased abundance of lipid droplets. Alternatively, when the concentration of Brij 35 exceeded 32 g L-1 , a large amount of substances accumulated on the surface of the fungal wall, permeability reduced, and the degree of oil droplet dispersion in cells decreased. Further, during extractive fermentation, Brij 35 induced formation of a grid structure on the fungal wall surface beginning on day 2, increased the number of intracellular lipid droplets, and promoted intracellular pigment secretion into the extracellular environment. When the cloud point temperature in the fermentation system approached that of fermentation, the nonionic surfactant exhibited stronger Monascus pigment extraction capacity, thereby enhancing pigment yield. Hence, Brij 35 can improve pigment stability and effectively reduce damage caused by natural factors, such as light and temperature. CONCLUSION: Brij 35 promotes the secretion of pigment by changing the fungal wall structure and cloud point, as well as by improving pigment stability. © 2020 Society of Chemical Industry.

Carminic Acid Stabilized with Aluminum-Magnesium Hydroxycarbonate as New Colorant Reducing Flammability of Polymer Composites.

In this study, hybrid pigments based on carminic acid (CA) were synthesized and applied in polymer materials. Modification of aluminum-magnesium hydroxycarbonate (LH) with CA transformed the soluble chromophore into an organic-inorganic hybrid colorant. Secondary ion mass spectroscopy (TOF-SIMS), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), thermogravimetric analysis (TGA), scanning electron microscopy (SEM), and UV-Vis spectroscopy were used to study the structure, composition, and morphology of the insoluble LH/CA colorant. Successful modification of the LH was confirmed by the presence of interactions between the LH matrix and molecules of CA. XPS analysis corroborated the presence of CA complexes with Mg2+ ions in the LH host. The batochromic shift in UV-Vis spectra of the organic-inorganic hybrid colorant was attributed to metal-dye interactions in the organic-inorganic hybrid colorants. Strong metal-dye interactions may also be responsible for the improved solvent resistance and chromostability of the modified LH. In comparison to uncolored ethylene-norbornene copolymer (EN), a modified EN sample containing LH/CA pigment showed lower heat release rate (HRR) and reduced total heat release (THR), providing the material with enhanced flame retardancy.

One-stage immobilization of the microalga Porphyridium purpureum using a biocompatible silica precursor and study of the fluorescence of its pigments.

The biocompatible silica precursor tetrakis(2-hydroxyethyl)orthosilicate with ethylene glycol residues was used instead of the common alcohol-containing tetraethoxysilane for the first time to prepare a biorecognition element by entrapping the marine microalga Porphyridium purpureum into a silica matrix by a one-stage sol-gel procedure at conditions (pH, ionic strength, and temperature) appropriate for living cells. We show that the microalga immobilized in this way fully maintains its viability and functionality. We furthermore show that the silica matrix had a stabilizing effect, providing microalgal survival and functionality at increased temperature. The high optical transparency of the silica matrix allowed us to study the optical properties of Porphyridium purpureum thoroughly. When irradiated by a laser, intense fluorescence of chlorophyll-a and phycoerythrin of the photosynthetic system was observed. The characteristics of this fluorescence differed notably from that observed with P. purpureum in suspension before immobilization; possible reasons for this and an underlying mechanism are discussed.

Dissecting pigment architecture of individual photosynthetic antenna complexes in solution.

Oligomerization plays a critical role in shaping the light-harvesting properties of many photosynthetic pigment-protein complexes, but a detailed understanding of this process at the level of individual pigments is still lacking. To study the effects of oligomerization, we designed a single-molecule approach to probe the photophysical properties of individual pigment sites as a function of protein assembly state. Our method, based on the principles of anti-Brownian electrokinetic trapping of single fluorescent proteins, step-wise photobleaching, and multiparameter spectroscopy, allows pigment-specific spectroscopic information on single multipigment antennae to be recorded in a nonperturbative aqueous environment with unprecedented detail. We focus on the monomer-to-trimer transformation of allophycocyanin (APC), an important antenna protein in cyanobacteria. Our data reveal that the two chemically identical pigments in APC have different roles. One (α) is the functional pigment that red-shifts its spectral properties upon trimer formation, whereas the other (ß) is a "protective" pigment that persistently quenches the excited state of α in the prefunctional, monomer state of the protein. These results show how subtleties in pigment organization give rise to functionally important aspects of energy transfer and photoprotection in antenna complexes. The method developed here should find immediate application in understanding the emergent properties of other natural and artificial light-harvesting systems.

The Black Bug Myth: Selective photodestruction of pigmented pathogens.

BACKGROUND AND OBJECTIVE: It is commonly believed that pigmented pathogens are selectively targeted by dental lasers. To test this notion optical diffuse reflection spectroscopy (DRS) was used to obtain absorption spectra for the periodontal pathogens, Porphyromonas gingivalis (Pg) and Prevotella intermedia (Pi). MATERIALS AND METHODS: Spectra from 400 to 1,100 nm wavelengths of Pg colonies cultured with different concentrations of hemin were obtained to test the hypothesis that "visual pigmentation" predicts absorption of near-infrared (IR) dental laser energy. Ablation threshold at 1,064 nm [1] was measured for the pathogenic fungus, Candida albicans (Ca). RESULTS: The hypothesis was demonstrated to be true at 810 nm, it was false at 1,064 nm. Diode laser (810 nm) efficacy and "depth of kill" is dependent on hemin availability from 400 to about 900 nm. Pg and Pi absorption at 1,064 nm (µa = 7.7 ± 2.6 cm(-1) ) is independent of hemin availability but is determined by another unknown chromophore. Ca is non-pigmented but very sensitive to 1,064 nm irradiation. CONCLUSIONS: The amount of visual pigmentation does not necessarily predict sensitivity to dental laser irradiation. Spectra in visible and near-IR wavelengths demonstrate a large difference in absorption between soft tissue and Pg or Pi. This difference represents a host/pathogen differential sensitivity to laser irradiation, the basis for selective photoantisepsis. Lasers Surg. Med. 48:706-714, 2016. © 2016 Wiley Periodicals, Inc.

A review on the role of pH-sensitive natural pigments in biopolymers based intelligent food packaging films.

As food packaging evolves, consumer interests are shifting from traditional to intelligent food packaging systems. Intelligent packaging includes active components that display changes in a visual or interactive form perceivable by consumers. This offers real-time monitoring of the quality and shelf life of the packaged food and enhances transparency. For example, pH-sensitive natural pigment-based films change color in response to variations in pH levels, enabling the film/labels to reflect alterations in the acidity or basicity of the food inside the package. Natural pigments like anthocyanins, curcumin, betalains, chlorophyll, and carotenoids have been comprehensively reported for developing biodegradable pH-sensitive films of starch, protein, chitosan, and cellulose. Natural pigments offer great compatibility with these biopolymers and improve the other performance parameters of the films. However, these films still lack the strength and versatility of petroleum-based synthetic plastic films. But these films can be used as an indicator and combined with primary packaging to monitor freshness, time-temperature, and leak for muscle foods, dairy products, fruits and vegetables, and bakery products. Therefore, this review provides a detailed overview of pH-sensitive pigments, their compatibility with natural polymers, their role in film performance in monitoring, and their food packaging applications.

Pectin forms polymeric pigments by complexing anthocyanins during red winemaking and ageing.

The long-term stability of red wine color depends on the formation of polymeric pigments from anthocyanins. Although there is still a lot of uncertainty about the specific structure of this diverse group of pigments, there is consensus that they are reaction products of anthocyanins and other polyphenols. Interactions between anthocyanins and pectic polysaccharides have been suggested to stabilize anthocyanins. This study explores the impact of such interactions by adding pectin during red winemaking. The results demonstrate that these interactions induce the formation of additional polymeric pigments which enhance the pigment stability during fermentation and aging. While initial pigment formation is higher in wines with added pectin, a notable proportion of the complexes degrades in the later stages of fermentation. Presumably, tannins form insoluble complexes with pectin, reducing tannin concentration by more than 300 mg/L. Anthocyanin concentrations decrease by over 400 mg/L, and polymeric pigments double. Anthocyanins that form polymeric pigments with pectic polysaccharides expand the range of pigments in red wines with possible consequences for the sensory properties of the wine. These findings highlight the complex interactions between pectin, anthocyanins, and tannins, and their influence on pigment formation and wine composition during fermentation and aging.

An antioxidant hydrogel dressing with wound pH indication function prepared based on silanized bacterial nanocellulose crosslinked with beet red pigment extract.

Maintaining wound moisture and monitoring of infection are crucial aspects of chronic wound treatment. The development of a pH-sensitive functional hydrogel dressing is an effective approach to monitor, protect, and facilitate wound healing. In this study, beet red pigment extract (BRPE) served as a native and efficient pH indicator by being grafted into silane-modified bacterial nanocellulose (BNC) to prepare a pH-sensitive wound hydrogel dressing (S-g-BNC/BRPE). FTIR confirmed the successful grafting of BRPE into the BNC matrix. The S-g-BNC/BRPE showed superior mechanical properties (0.25 MPa), swelling rate (1251 % on average), and hydrophilic properties (contact angle 21.83°). The composite exhibited a notable color change as the pH changed between 4.0 and 9.0. It appeared purple-red when the pH ranged from 4.0 to 6.0, and appeared light pink at pH 7.0 and 7.4, and appeared ginger-yellow at pH 8.0 and 9.0. Subsequently, the antioxidant activity and cytotoxicity of the composite was evaluated, its DPPH·, ABTS+, ·OH scavenging rates were 32.33 %, 19.31 %, and 30.06 %, respectively, and the cytotoxicity test clearly demonstrated the safety of the dressing. The antioxidant hydrogel dressing, fabricated with a cost-effective and easy method, not only showed excellent biocompatibility and dressing performance but could also indicated the wound state based on pH changes.

Complexation of anthocyanins, betalains and carotenoids with biopolymers: An approach to complexation techniques and evaluation of binding parameters.

Natural pigments are bioactive compounds that can present health-promoting bioactivities in the human body. Due to their strong coloring properties, these compounds have been widely used as color additives as an alternative to artificial colorants. However, since these pigments are unstable under certain conditions, such as the presence of light, oxygen, and heat, the use of complexation and encapsulation techniques with biopolymers is in demand. Moreover, some functional properties can be achieved by using natural pigments-biopolymers complexes in food matrices. The complexation and encapsulation of natural pigments with biopolymers consist of forming a complex with the aim to make these compounds less susceptible to oxidative and degrading agents, and can also be used to improve their solubility in different media. This review aims to discuss different techniques that have been used over the last years to create natural pigment-biopolymers complexes, as well as the recent advances, limitations, effects, and possible applications of these complexes in foods. Moreover, the understanding of thermodynamic parameters between natural pigments and biopolymers is very important regarding the complex formation and their use in food systems. In this sense, thermodynamic techniques that can be used to determine binding parameters between natural pigments and potential wall materials, as well as their applications, advantages, and limitations are presented in this work. Several studies have shown an improvement in many aspects regarding the use of these complexes, including increased thermal and storage stability. Nonetheless, data regarding the biological effects on the human body and the sensory acceptance of natural pigments-biopolymers complexes in food systems are scarce in the literature.

Nanoemulsion containing Yellow Monascus pigment : Fabrication, characterization, storage stability, and lipase hydrolytic activity in vitro digestion.

The natural pigment of monascus is favored by human for its special coloring and physiological activity, and its development and application have attracted much attention. In this study, a novel corn oil-based nanoemulsion encapsulated with Yellow Monascus Pigment crude extract (CO-YMPN) was successfully prepared via the phase inversion composition method. The fabrication and stable conditions of the CO-YMPN including Yellow Monascus pigment crude extract (YMPCE) concentration, emulsifier ratio, pH, temperature, ionic strength, monochromatic light and storage time were investigated systemically. The optimized fabrication conditions were the emulsifier ratio (5:3 ratio of Tween 60 to Tween 80) and the YMPCE concentration (20.00% wt%)). Additionally, the DPPH radical scavenging capability of the CO-YMPN (19.47 ± 0.52%) was more excellent than each YMPCE or corn oil. Moreover, the kinetic analysis results based on Michaelis-Menten equation and constant revealed that CO-YMPN could improve lipase hydrolysis capacity. Therefore, the CO-YMPN complex had excellent storage stability and water solubility in the final water system, and the YMPCE showed brilliant stability.

Overproduction of a potential red pigment by a specific self-immobilization biomembrane-surface liquid culture of Penicillium novae-zeelandiae.

A specific self-immobilization biomembrane-surface liquid culture (SIBSLC) was developed to overproduce a potential penicillium red pigment. Statistic analysis shows that both glucose concentration and membrane diameter are important factors influencing the yield of red pigment. After the optimization using central composite experimental design, the maximum yield of red pigment in shake flask reaches 4.25 g/l. The growth of strain HSD07B consists of three phases, and the pigment secreted in the decelerated phase, is originated from the interior of biomembrane where glucose exhaustion occurs. In addition, the batch and continuous SIBSLC were conducted for production of the pigment, and the latter was more competitive in consideration of the fact that it not only increased 61.5 % of pigment productivity, but also simplified the production process. Moreover, the pigment produced by SIBSLC is potentially acceptable for food applications although it is distinguished from the co-cultured red pigment we reported previously in components.

[Comparative structural and functional characteristics of different forms of Saccharomyces cerevisiae red pigment and its synthetic analogue].

Structural and functional characteristics of the yeast red pigment (product of polymerization of N1-(beta-D-ribofuranosyl)-5-aminoimadazole), isolated from adel 1 mutant cells of Saccharomyces cerevisiae, its deribosylated derivatives (obtained by acid hydrolysis) and its synthetic pigment analogue (product of polymerization of N1-methyl-5-aminoimadazole in vitro) has been obtained. Products of in vitro polymerization were identified using mass spectrometry. The ability of these pigments to inhibit amyloid formation using insulin fibrils was compared. The entire compounds studied were able to interact with amyloids and inhibit their growth. Electron and atomic force microscopy revealed a common feature inherent in the insulin fibrils formed in presence of these compounds--they were merged into conglomerates that were more stable and resistant to the effects of ultrasound in comparison with insulin aggregates grown without pigments. We speculate that all these compounds can cause coalescence of fibrils, partially block their loose ends and, thereby, inhibit the attachment of new monomers to growing fibrils.

Effect of different light-curing modes on degree of conversion, staining susceptibility and stain's retention using different beverages in a nanofilled composite resin.

STATEMENT OF PROBLEM: It is unknown whether the staining pigment concentration would affect the color of composite resin and whether the absorption of the staining pigment is related to the degree of conversion (DC). PURPOSE: The purpose of this study was to evaluate the effect of light-curing units (LCUs) on DC, superficial staining (ΔE), and pigment concentration (PC) in a nanofilled composite resin (Z350, 3M ESPE) using different beverages. MATERIALS AND METHODS: Specimens were polymerized for 20 seconds using four LCUs (N=50): quartz-tungsten-halogen (QTH)--450 mW/cm(2); laser (LAS)--300 mW/cm(2); second-generation light-emitting diode (LED)-1100 mW/cm(2); and third generation LED--700 mW/cm(2). DC (%) was measured using Fourier transform infrared spectroscopy. Specimens concerning each group (N=10) were then immersed in one of the solutions (distilled water, red wine, whisky, coffee, and cola--40 min/day, for 40 days). Specimen's color was measured before and after exposure to solutions using a colorimeter (Commission Internacionale de I'Eclairaga L*a*b* color scale), and ΔE was calculated. Specimens were then prepared for the spectrophotometric analysis to measure PC. Data were submitted to two-way analysis of variance and Tukey's test (p=0.05). RESULTS: DC: QTH presented the lowest DC, with statistical differences for LAS, LED 2, and LED 3. Whisky and wine showed lower PC mean values than cola and coffee. No statistical difference was observed for LCUs regarding PC and all staining solutions, except cola. Whisky showed the highest values for ΔE regarding all LCUs. Wine showed statistically lower ΔE than whisky, with water presenting the lowest ΔE. LAS and QTH showed higher values than LED 2 concerning ΔE. CONCLUSION: LCUs interfered with DC and altered the PC and ΔE of the composite resin submitted to different staining solutions. There was no correlation among DC, PC, and ΔE. CLINICAL SIGNIFICANCE: Light-curing modes might interfere with staining susceptibility, stain's retention, and DC of a composite resin, compromising the clinical performance. The highest pigment absorption was not associated with the highest superficial staining of the composite resin. Alcoholic drinks lead to greater superficial staining and non-alcoholic solutions lead to a higher pigment concentration.

Size exclusion chromatography for the removal of pigments from extracellular ligninolytic enzyme extracts from decayed wheat straw.

Solid-state fermentation of wheat straw was carried out by a native white rot basidiomycete Daedaleopsis flavida strain 5A. Extract prepared from the 12-day decayed wheat straw contained extracellular ligninolytic enzymes like manganese peroxidase (MnP), manganese-independent peroxidase (MIP), lignin peroxidase (LiP) and laccase along with straw-degraded products and pigments. Sephacryl S-200 size exclusion chromatography in 16/100 column was used for the separation of these ligninolytic enzymes and straw-degraded products and pigments. Recovery of pigment-free ligninolytic enzyme activities as protein was 40% of the total proteins loaded and specific LiP activity increased 34 fold after size exclusion chromatography. Thus accurate estimation of LiP by veratryl alcohol oxidation assay was possible only after the removal of interfering pigments. The reproducibility of size exclusion chromatography is adjudged satisfactory from the consistent results obtained after seven repetitive uses of matrices.

Pigment chemistry: the red sweat of the hippopotamus.

Within a few minutes of perspiration, the colourless, viscous sweat of the hippopotamus gradually turns red, and then brown as the pigment polymerizes. Here we isolate and characterize the pigments responsible for this colour reaction. The unstable red and orange pigments turn out to be non-benzenoid aromatic compounds that are unexpectedly acidic and have antibiotic as well as sunscreen activity.

Investigation on decolorization kinetics and thermodynamics of lignocellulosic xylooligosaccharides by highly selective adsorption with Amberlite XAD-16N.

Xylooligosaccharides (XOS) are booming in food, pharmacy and feed industries that they have attracted great interest in the high-value utilization of lignocellulose. Selective acidolysis dominates the commercial production of XOS except for intractable color contaminations derivate from ligoncellulosic degradation. Based on a detailed kinetics and thermodynamics investigation, Amberlite XAD-16N was designated as preferred decolorant because of its high adsorption-selectivity for XOS and the colored contaminants. The adsorption of the main compositions in lignocellulosic acidolysis solution was well described by Langmuir models, the kinetics were clearly fitted by Pseudo-second-order model, showing that the adsorption was controlled by electron sharing/transfer between the resin cross-linking groups and colorant. The adsorption mechanism was also verified by the adsorption-simulation of three detected typical colorants. The thermodynamics clearly indicated a spontaneous endothermic reaction. This study provides an important approach for industrial technology development to not only xylooligosaccharides production and lignocellulosic acidolysis, but also Amberlite XAD-16N adsorbent.

Effective removal matrix interferences by a modified QuEChERS based on the molecularly imprinted polymers for determination of 84 polychlorinated biphenyls and organochlorine pesticides in shellfish samples.

A modified quick, easy, cheap, effective, rugged, and safe (QuEChERS) procedure combined with GC-MS/MS detection approach using a dynamic multiple reaction monitoring (DMRM) mode was successfully applied for the simultaneous analysis of 84 polychlorinated biphenyls (PCBs) and organochlorine pesticides (OCPs) in shellfish samples. The novel molecular imprinted polymers (MIPs) were synthesized by precipitation polymerization and characterized by Scanning electron microscopy, Brunauer-Emmett-Teller, Fourier transform infrared spectra and adsorption experiment. The MIPs exhibited good adsorption capability to pigment coextractives in shellfish samples without the loss of analytes compared with other sorbents. Under optimal conditions, spiked experiments in sinonovacula, mussel, and clam at 10.0-100.0 µg/kg concentrations showed excellent recoveries ranging from 70% to 120% for all analytes with the relative standard deviations of <10%. The developed method showed good linearity with the correlation coefficient above 0.9980, and the limits of quantification were in the range of 0.01-9.02 µg/kg. The developed QuEChERS procedure combined with GC-MS/MS was successfully applied to 84 PCBs and OCPs residues detection in shellfish samples.

Response surface optimization of the water immersion extraction and macroporous resin purification processes of anhydrosafflor yellow B from Carthamus tinctorius L.

In this study,based on a developed high performance liquid chromatographic quantitative method, the suitable extraction and purification conditions of anhydrosafflor yellow B (AHSYB) from safflower were determined by response surface methodology. The optimal water immersion extraction parameters were as follows: liquid to solid ratio of 22:1; extraction temperature of 75 °C; extraction time of 35 min. Under these conditions, the maximum extraction yield of AHSYB reached 0.465%. The aqueous extract was further purified by HPD-300 macroporous resin. The optimum adsorption conditions were: pH 2.8; adsorption flow rate of 1.9 mL/min; solution concentration of 0.06 g/mL. The optimum desorption conditions were: ethanol concentrations of 74%; desorption flow rate of 1.6 mL/min; elution volume of 4.4 BV. Under these conditions, the maximum adsorption ratio and desorption ratio reached 1.095 and 0.906 mg/g, respectively. The content of AHSYB reached 6.83%, which was 2.91 times higher than that before purification. PRACTICAL APPLICATION: The suitable conditions for water immersion extraction and macroporous resin purification of AHSYB are first determined, which facilitates the further utilization of AHSYB as a food and drug.

Design and validation of antibacterial and pH response of cationic guar gum film by combining hydroxyethyl cellulose and red cabbage pigment.

A simple and feasible method was adopted to construct the antibacterial and pH response of cationic guar gum (CGG) composite films (CGG-HEC, RC) through using hydroxyethyl cellulose (HEC) as an enhancer and red cabbage (RC) as a smart active substance. The effect of different HEC content on the binary composite films (CGG-HEC) performance shows that the highest tensile strength (51.59 MPa) can be obtained by adding 10% HEC due to the good compatibility between CGG and HEC. The ternary composite film (RC3) with 10% HEC and 3% RC addition has good performance in all aspects, such as high tensile strength (65.41 MPa), appropriate water vapor transmission coefficient (1.08), and good thermodynamic stability. In addition, RC3 has good antibacterial properties against E. coli and Staphylococcus aureus, taking advantage of the antibacterial properties of CGG and RC. RC3 can respond to changes in environmental pH and has a significant color change, and also has a significant color change when detecting the deterioration of pork and soy milk. Therefore, the ternary composite film (RC3) has good mechanical properties, antibacterial and intelligent response characteristics, and may be used in intelligent antibacterial packaging.

Dyeing of bacterial cellulose films using plant-based natural dyes.

The aim of this work was to test the use of plant-based natural dyes on bacterial cellulose (BC) to add aesthetic value to dyed pellicles while maintaining the mechanical properties. Natural pigments from Clitoria ternatea L. and Hibiscus rosa-sinensis were tested. The commercial ARAQCEL RL 500 was also used for comparison purposes. The behavior of biocellulose regarding dye fixation, rehydration, tensile strength, and elasticity was evaluated in comparison to the dried biomaterial, showing that dyeing is a process that can be performed on hydrated BC. Dyeing the BC films through an innovative process maintained the crystallinity, thermal stability and mechanical strength of the BC and confirmed the compatibility of the membrane with the dyes tested, from the observed Scanning Electron Microscopy (SEM) morphology of nanofibers. Dyed biomaterial can be applied to various products, as confirmed by the results of the mechanical tests. As environmental awareness and public concern regarding pollution increase, the combination of natural dyes and BC pellicles can produce an attractive new material for the textile industry.