Chlorophyll (Chl), the most widely distributed natural pigment in nature, is limited in use due to its poor stability. This study refers to the aggregation structure of Chl and carotene (Car) in natural photosynthetic systems, hoping to improve the photostability of Chl by constructing Chl/Car aggregates. The stability protection effect of Car on Chl was explored by designing different ratios of Chl and Car aggregation systems. The configuration of Chl/Car aggregates was optimized through ab initio molecular dynamics, and the aggregation mechanism of the aggregates and the photoprotection mechanism of Chl by Car were elucidated through quantum chemical calculations and wave function analysis. Chl/Car had a 27.22% higher Chl retention rate than free Chl after 7 d of illumination, with a Chl to Car ratio of 1.66:1. A configuration of the Chl/Car aggregates which Car's conjugated olefin chain interacts extensively with the porphyrin ring and bent phytyl chain of Chl made them more stable. The photoprotective mechanism of Car on Chl in the Chl/Car aggregates is elucidated. Car's conjugated polyene chain provides HOMO orbitals to the Chl/Car aggregates. It demonstrated that Car supplies electrons in the low-lying excited states S2 and S4, indicating it is more susceptible to damage, protecting Chl. This research will promote the development of natural color formulas and ensure the health of consumers.

Chlorophyll (Chl), the most widely distributed natural pigment in nature, is limited in use due to its poor stability. This study refers to the aggregation structure of Chl and carotene (Car) in natural photosynthetic systems, hoping to improve the photostability of Chl by constructing Chl/Car aggregates. The stability protection effect of Car on Chl was explored by designing different ratios of Chl and Car aggregation systems. The configuration of Chl/Car aggregates was optimized through ab initio molecular dynamics, and the aggregation mechanism of the aggregates and the photoprotection mechanism of Chl by Car were elucidated through quantum chemical calculations and wave function analysis. Chl/Car had a 27.22% higher Chl retention rate than free Chl after 7 d of illumination, with a Chl to Car ratio of 1.66:1. A configuration of the Chl/Car aggregates which Car's conjugated olefin chain interacts extensively with the porphyrin ring and bent phytyl chain of Chl made them more stable. The photoprotective mechanism of Car on Chl in the Chl/Car aggregates is elucidated. Car's conjugated polyene chain provides HOMO orbitals to the Chl/Car aggregates. It demonstrated that Car supplies electrons in the low-lying excited states S2 and S4, indicating it is more susceptible to damage, protecting Chl. This research will promote the development of natural color formulas and ensure the health of consumers.

The promising future of natural colors in the food industry aligns with the shift in consumer preference toward healthier food options. These naturally derived ingredients gradually replace their artificial counterparts and find applications in a wide range of food categories, and aquatic products have emerged as one of them. In this work, we introduced the characteristics and extraction of several main types of natural pigments and also explored the positive outcomes of integrating the pigments, such as carotenoids, curcumin, anthocyanins, and betalains, in aquatic product processing and preservation. Their outstanding antioxidant and dyeing properties contribute to the production and storage of various aquatic products. This review aims to provide a comprehensive understanding of the current state of natural pigment applications in aquatic products and to provide inspiration for future research and industry practices.

The promising future of natural colors in the food industry aligns with the shift in consumer preference toward healthier food options. These naturally derived ingredients gradually replace their artificial counterparts and find applications in a wide range of food categories, and aquatic products have emerged as one of them. In this work, we introduced the characteristics and extraction of several main types of natural pigments and also explored the positive outcomes of integrating the pigments, such as carotenoids, curcumin, anthocyanins, and betalains, in aquatic product processing and preservation. Their outstanding antioxidant and dyeing properties contribute to the production and storage of various aquatic products. This review aims to provide a comprehensive understanding of the current state of natural pigment applications in aquatic products and to provide inspiration for future research and industry practices.

Carotenoids are colored bioactive substances increasingly used due to their antioxidant properties, vitamin A precursor role, and ability to function as a natural food color. Knowledge of carotenoid behavior during high-heat processing and subsequent storage in emulsified food matrix is essential to expand their application natural food colors and neutraceuticals. Firstly, the physical, thermal, and colloidal stability of emulsions constructed from octenyl succinic anhydride-modified starch (OSA starch)-chitosan multilayered interfaces were investigated. Results of charge reversal from −32.4 ± 1.9 mV to +38.0 ± 0.8 mV indicate that multilayered interfaces were formed in emulsions. As measured by Z-average size, the emulsions were stable after the thermal treatment at 121 °C for 60 min, thus demonstrating a novel heat-stable multilayered emulsion. Subsequently, a select multilayered emulsion was loaded with β-carotene, and its storage stability was assessed. The degradation of β-carotene in an oil-in-water emulsion was better described with zeroth order kinetics; β-carotene dissolved in bulk oil was better described using a second-order kinetic equation. The presence of an encapsulating material around the oil droplets loaded with β-carotene enhanced its stability, which makes it instrumental in extending shelf-life and maintaining a consistent appearance. The results can be used to predict the availability of β-carotene during storage.

Carotenoids are colored bioactive substances increasingly used due to their antioxidant properties, vitamin A precursor role, and ability to function as a natural food color. Knowledge of carotenoid behavior during high-heat processing and subsequent storage in emulsified food matrix is essential to expand their application natural food colors and neutraceuticals. Firstly, the physical, thermal, and colloidal stability of emulsions constructed from octenyl succinic anhydride-modified starch (OSA starch)-chitosan multilayered interfaces were investigated. Results of charge reversal from −32.4 ± 1.9 mV to +38.0 ± 0.8 mV indicate that multilayered interfaces were formed in emulsions. As measured by Z-average size, the emulsions were stable after the thermal treatment at 121 °C for 60 min, thus demonstrating a novel heat-stable multilayered emulsion. Subsequently, a select multilayered emulsion was loaded with β-carotene, and its storage stability was assessed. The degradation of β-carotene in an oil-in-water emulsion was better described with zeroth order kinetics; β-carotene dissolved in bulk oil was better described using a second-order kinetic equation. The presence of an encapsulating material around the oil droplets loaded with β-carotene enhanced its stability, which makes it instrumental in extending shelf-life and maintaining a consistent appearance. The results can be used to predict the availability of β-carotene during storage.

Umami peptides, the flavor compounds mainly derived from natural proteins, provide a pleasant taste for humans and exhibit a variety of biological activities, such as antioxidant and lipid-lowering properties. Marine proteins, which serve as excellent sources of umami peptides, have become a focal point of research. This review introduces the research progress on reported marine umami peptides. Firstly, it discusses the structural characteristics of umami peptides and the mechanism behind their formation to create an umami taste. It then presents several commonly used techniques for preparing and regulating umami peptides while summarizing the advantages and disadvantages of each technique. Finally, this review describes the potential application prospects for core technologies within Industry 4.0—such as molecular simulation, artificial intelligence, big data analysis, cloud computing, and blockchain technology—which could bring new opportunities for the development of marine umami peptides.

Umami peptides, the flavor compounds mainly derived from natural proteins, provide a pleasant taste for humans and exhibit a variety of biological activities, such as antioxidant and lipid-lowering properties. Marine proteins, which serve as excellent sources of umami peptides, have become a focal point of research. This review introduces the research progress on reported marine umami peptides. Firstly, it discusses the structural characteristics of umami peptides and the mechanism behind their formation to create an umami taste. It then presents several commonly used techniques for preparing and regulating umami peptides while summarizing the advantages and disadvantages of each technique. Finally, this review describes the potential application prospects for core technologies within Industry 4.0—such as molecular simulation, artificial intelligence, big data analysis, cloud computing, and blockchain technology—which could bring new opportunities for the development of marine umami peptides.

In this study, three representative pears ('Yali' Pear, 'Huangguan' Pear, and 'Xuehua' Pear) peel/flesh polyphenol extracts were characterized by their antioxidant activity, polyphenol composition, and in vitro cholesterol/cholates binding capacity. 'Yali' Pear polyphenol extracts were selected to further investigate the mechanism of in vitro cholesterol/cholates lowering capacity. Lagergren adsorption kinetic and Freundlich isotherm models confirmed the occurrence of this combination. Turbidity, average particle size, transmission electron microscopy, and zeta potential combined confirmed the existence of some interaction between polyphenols and cholesterol/cholates. Cholesterol/cholates quenched the exogenous fluorescence of polyphenols by static mechanism. The thermodynamic interaction results revealed that the interaction between polyphenols and cholesterol is a spontaneous process, primarily driven by hydrogen bonding and hydrophobic interactions. Overall, this study aimed to investigate the confirmation of the binding removal properties of pear polyphenols on cholesterol/cholates to mitigate the adverse health effects of a high-fat diet.

In this study, three representative pears ('Yali' Pear, 'Huangguan' Pear, and 'Xuehua' Pear) peel/flesh polyphenol extracts were characterized by their antioxidant activity, polyphenol composition, and in vitro cholesterol/cholates binding capacity. 'Yali' Pear polyphenol extracts were selected to further investigate the mechanism of in vitro cholesterol/cholates lowering capacity. Lagergren adsorption kinetic and Freundlich isotherm models confirmed the occurrence of this combination. Turbidity, average particle size, transmission electron microscopy, and zeta potential combined confirmed the existence of some interaction between polyphenols and cholesterol/cholates. Cholesterol/cholates quenched the exogenous fluorescence of polyphenols by static mechanism. The thermodynamic interaction results revealed that the interaction between polyphenols and cholesterol is a spontaneous process, primarily driven by hydrogen bonding and hydrophobic interactions. Overall, this study aimed to investigate the confirmation of the binding removal properties of pear polyphenols on cholesterol/cholates to mitigate the adverse health effects of a high-fat diet.

In this study, static and dynamic desorption methods, infrared spectroscopy and, in vitro antioxidant modeling were used to isolate, purify, and investigate the bioactivity of melanoidins extracted from hypoheat-induced Lycium barbarum L. The results showed that melanoidin fractions with molecular weight in the range of 3−10 kDa were the dominant and most valuable fractions. In the purification phase, the optimal purification conditions were: a loading concentration of 4 mg·mL−1, elution volume of 6 BV, and an elution flow rate of 1 mL·min−1. Purified dominant melanoidin fractions (UF3) exhibited typical Maillard reaction (MR) characteristics in FTIR. The storage stability showed that sunlight and heat treatment exacerbated the instability of the purified UF3. At the same time it was relatively stable under dark conditions and incandescent light, with a retention rate of about 90%. After in vitro digestion, the purified UF3 still exhibited good antioxidant activity, and the DPPH scavenging activity and hydroxyl free radical scavenging ability reached more than 60%.

In this study, static and dynamic desorption methods, infrared spectroscopy and, in vitro antioxidant modeling were used to isolate, purify, and investigate the bioactivity of melanoidins extracted from hypoheat-induced Lycium barbarum L. The results showed that melanoidin fractions with molecular weight in the range of 3−10 kDa were the dominant and most valuable fractions. In the purification phase, the optimal purification conditions were: a loading concentration of 4 mg·mL−1, elution volume of 6 BV, and an elution flow rate of 1 mL·min−1. Purified dominant melanoidin fractions (UF3) exhibited typical Maillard reaction (MR) characteristics in FTIR. The storage stability showed that sunlight and heat treatment exacerbated the instability of the purified UF3. At the same time it was relatively stable under dark conditions and incandescent light, with a retention rate of about 90%. After in vitro digestion, the purified UF3 still exhibited good antioxidant activity, and the DPPH scavenging activity and hydroxyl free radical scavenging ability reached more than 60%.

β-ionone has various biological activities, such as anti-inflammatory, antimicrobial, and anticancer effects. The pathogenesis of ulcerative colitis is correlated with immune dysfunction, intestinal barrier damage, and gut microbiota imbalance. However, whether β-ionone has preventive efficacy against ulcerative colitis is unknown. This study investigated the effect of β-ionone on dextran sulfate sodium-induced ulcerative colitis and the underlying molecular mechanisms involved. The ulcerative colitis mouse model was induced by 1.5% dextran sulfate sodium for 10 d. Meanwhile, 200 mg/kg β-ionone was administrated to the mice. Body weight, colon length, colon tissue pathology, colon tissue inflammatory cytokines, colonic oxidative stress, and barrier function were assessed. The composition and structure of gut microbiota were profiled using 16S rRNA sequencing. The results showed that β-ionone supplementation effectively prevented ulcerative colitis by ameliorating colonic tissue damage, reducing inflammatory phenomena, and protecting the colonic epithelial mucosal barrier. β-ionone also protected mice from dextran sulfate sodium-induced gut microbiota disturbance by modifying the overall structure and function of the gut microbiota community and increasing the relative abundance of beneficial gut microbiota. The Spearman correlation analysis revealed that the changes in abundance of the gut microbiota were correlated with ulcerative colitis-related indicators. Overall, this study demonstrated that β-ionone has a preventive effect on ulcerative colitis in mice, and the underlying mechanism may be associated with the protection of the gut barrier and regulation of the gut microbiota. These results are conducive to promoting clinical trials and product development of β-ionone for the prevention and treatment of ulcerative colitis.

β-ionone has various biological activities, such as anti-inflammatory, antimicrobial, and anticancer effects. The pathogenesis of ulcerative colitis is correlated with immune dysfunction, intestinal barrier damage, and gut microbiota imbalance. However, whether β-ionone has preventive efficacy against ulcerative colitis is unknown. This study investigated the effect of β-ionone on dextran sulfate sodium-induced ulcerative colitis and the underlying molecular mechanisms involved. The ulcerative colitis mouse model was induced by 1.5% dextran sulfate sodium for 10 d. Meanwhile, 200 mg/kg β-ionone was administrated to the mice. Body weight, colon length, colon tissue pathology, colon tissue inflammatory cytokines, colonic oxidative stress, and barrier function were assessed. The composition and structure of gut microbiota were profiled using 16S rRNA sequencing. The results showed that β-ionone supplementation effectively prevented ulcerative colitis by ameliorating colonic tissue damage, reducing inflammatory phenomena, and protecting the colonic epithelial mucosal barrier. β-ionone also protected mice from dextran sulfate sodium-induced gut microbiota disturbance by modifying the overall structure and function of the gut microbiota community and increasing the relative abundance of beneficial gut microbiota. The Spearman correlation analysis revealed that the changes in abundance of the gut microbiota were correlated with ulcerative colitis-related indicators. Overall, this study demonstrated that β-ionone has a preventive effect on ulcerative colitis in mice, and the underlying mechanism may be associated with the protection of the gut barrier and regulation of the gut microbiota. These results are conducive to promoting clinical trials and product development of β-ionone for the prevention and treatment of ulcerative colitis.

The objective of the study was to examine the physicochemical properties and emulsification stability of three different Auricularia auricula polysaccharides (AAP) obtained through hot water extraction (AAP-W), hot acid extraction (AAP-A), and hot alkaline extraction (AAP-AL), respectively. The findings indicated that AAP-W exhibited superior emulsification stability compared to the other two polysaccharides. AAP-W was employed as a natural emulsifier for emulsion preparation, to examine the influence of varying polysaccharide concentrations and oil-water ratios on emulsion stability. Additionally, an investigation was conducted into the stability of the emulsions with respect to pH and salt ion concentration. The findings revealed that the most favorable polysaccharide concentration for the AAP-W emulsion was determined to be 1%, while the volume fraction of the oil phase was established at 0.5. It was also observed that the emulsion exhibited robust stability even in challenging conditions characterized by strong acidic (pH 3−5) or basic environments (pH 9−11), as well as high concentrations of salt ions (0−500 mM). Furthermore, the construction of an AAP-W emulsion system incorporating β-carotene was undertaken to enhance the preservation, bioavailability, and digestive stability of β-carotene, thereby expanding the potential applications of Auricularia auricula polysaccharides. This endeavor also presents a novel approach towards the advancement of novel functional food products.

The objective of the study was to examine the physicochemical properties and emulsification stability of three different Auricularia auricula polysaccharides (AAP) obtained through hot water extraction (AAP-W), hot acid extraction (AAP-A), and hot alkaline extraction (AAP-AL), respectively. The findings indicated that AAP-W exhibited superior emulsification stability compared to the other two polysaccharides. AAP-W was employed as a natural emulsifier for emulsion preparation, to examine the influence of varying polysaccharide concentrations and oil-water ratios on emulsion stability. Additionally, an investigation was conducted into the stability of the emulsions with respect to pH and salt ion concentration. The findings revealed that the most favorable polysaccharide concentration for the AAP-W emulsion was determined to be 1%, while the volume fraction of the oil phase was established at 0.5. It was also observed that the emulsion exhibited robust stability even in challenging conditions characterized by strong acidic (pH 3−5) or basic environments (pH 9−11), as well as high concentrations of salt ions (0−500 mM). Furthermore, the construction of an AAP-W emulsion system incorporating β-carotene was undertaken to enhance the preservation, bioavailability, and digestive stability of β-carotene, thereby expanding the potential applications of Auricularia auricula polysaccharides. This endeavor also presents a novel approach towards the advancement of novel functional food products.

To swiftly and noninvasively assess the freshness of bighead carp heads within simulated cold chain environments, an excitation-emission matrix fluorescence spectroscopy coupled with a long short-term memory network (EEM-LSTM) model was developed. Through the parallel factor algorithm based on analysis of residuals, diagnosis of core consistency, and split-half evaluation, three key fluorescent components from fish fillets were extracted, with the most significant components linked to tryptophan and NADH, both indicative of fish freshness. The EEM-LSTM model exhibited coherent trends in freshness indicators and demonstrated exceptional predictive capabilities for four freshness indicators simultaneously, achieving R2 values exceeding 0.8840 in simulated cold chain situations. Relative errors in the supermarket direct sales cold chain were less than 10%, surpassing those of the long-distance transport cold chain. Hence, the EEM-LSTM model stands validated for predicting fish freshness in simulated cold chains, holding promise for real-world aquatic product freshness forecasting within cold chain scenarios.

To swiftly and noninvasively assess the freshness of bighead carp heads within simulated cold chain environments, an excitation-emission matrix fluorescence spectroscopy coupled with a long short-term memory network (EEM-LSTM) model was developed. Through the parallel factor algorithm based on analysis of residuals, diagnosis of core consistency, and split-half evaluation, three key fluorescent components from fish fillets were extracted, with the most significant components linked to tryptophan and NADH, both indicative of fish freshness. The EEM-LSTM model exhibited coherent trends in freshness indicators and demonstrated exceptional predictive capabilities for four freshness indicators simultaneously, achieving R2 values exceeding 0.8840 in simulated cold chain situations. Relative errors in the supermarket direct sales cold chain were less than 10%, surpassing those of the long-distance transport cold chain. Hence, the EEM-LSTM model stands validated for predicting fish freshness in simulated cold chains, holding promise for real-world aquatic product freshness forecasting within cold chain scenarios.

The loss of pericarp greenness, wrinkling of the pericarp, and alteration of aroma are indicators of the ripening and senescence of lemons. In this study, lemons were soaked in 100 mg∙L-1 of gibberellin (GA) solutions for 5 min and stored at 14°C for 36 d under three relative humidity (RH) levels of 30%, 60%, and 90%, respectively. The changes in visual appearance, pigment metabolism, pericarpic microstructure, and volatile compounds of lemons during storage were evaluated. The results showed that GA pretreatment inhibited the color transformation from green to yellow of the flavedo and restrained fruit senescence. In addition, RH 90% effectively maintained the structural integrity of the oil gland, waxes, and stomata in the flavedo. GAs + RH 90% treatment maintained the fruit color index (L*, a*, b*, a*/b*, H°, C*) by inhibiting chlorophyll degradation and regulating carotenoid biosynthesis. Green lemons treated with GAs + RH 90% also showed reduced epidermal wrinkling, well-preserved cuticle, and stomatal structure, with a smooth and intact wax layer on the lemon pericarp. In addition, GAs + RH 90% treatment maintained the content of volatile aroma compounds, especially terpene. GAs + RH 90% had a great advantage in maintaining visual quality, delaying the deformation of tissue microstructure, preserving nutritional quality, and improving aroma. Thus, this treatment is potentially applicable for maintaining the storage quality of green lemons and extending their shelf life.

The loss of pericarp greenness, wrinkling of the pericarp, and alteration of aroma are indicators of the ripening and senescence of lemons. In this study, lemons were soaked in 100 mg∙L-1 of gibberellin (GA) solutions for 5 min and stored at 14°C for 36 d under three relative humidity (RH) levels of 30%, 60%, and 90%, respectively. The changes in visual appearance, pigment metabolism, pericarpic microstructure, and volatile compounds of lemons during storage were evaluated. The results showed that GA pretreatment inhibited the color transformation from green to yellow of the flavedo and restrained fruit senescence. In addition, RH 90% effectively maintained the structural integrity of the oil gland, waxes, and stomata in the flavedo. GAs + RH 90% treatment maintained the fruit color index (L*, a*, b*, a*/b*, H°, C*) by inhibiting chlorophyll degradation and regulating carotenoid biosynthesis. Green lemons treated with GAs + RH 90% also showed reduced epidermal wrinkling, well-preserved cuticle, and stomatal structure, with a smooth and intact wax layer on the lemon pericarp. In addition, GAs + RH 90% treatment maintained the content of volatile aroma compounds, especially terpene. GAs + RH 90% had a great advantage in maintaining visual quality, delaying the deformation of tissue microstructure, preserving nutritional quality, and improving aroma. Thus, this treatment is potentially applicable for maintaining the storage quality of green lemons and extending their shelf life.