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.

Chilling injury (CI) is a highly common physiological disorder in pomegranates during cold storage. Although several approaches have been investigated to mitigate the CI symptoms among some pomegranate cultivars, the fundamental and crucial environmental factor — the precise storage temperature for the 'Mengzi' cultivation remains unknown. This research evaluated the impact of storage temperatures of 0, 1, 2, 3, and 4 °C on the post-harvest quality of pomegranates. Results indicated that pomegranates stored at 2 °C exhibited the slightest color change and browning index. After storage of 130 d, pomegranates stored at 2 °C exhibited the lower CI index (82.79% reduction) and the lowest decay incidence (24.68% reduction) compared to those stored at 0 °C. The respiratory rate of pomegranates (2 °C) was also evidently suppressed (16.60%), along with a reduction in weight loss (3.46%). Furthermore, pomegranates stored at 2 °C exhibited the lowest activities of polyphenol oxidase (PPO) and peroxidase (POD), accompanied by the highest total phenolic content, which contributed to a reduction in malondialdehyde (MDA) accumulation. Relatively higher concentrations of soluble solids and titratable acid, as well as a higher sensory evaluation, were found in pomegranates stored at 2 °C. Consequently, it was inferred that the optimal temperature maintained cell membrane integrity modulated normal respiratory metabolism, and oxidative balance, and therefore alleviated CI and deterioration. This report can provide the guiding significance for the long-term storage of 'Mengzi' pomegranates under the condition of precise temperature control in phase temperature storage.

Chilling injury (CI) is a highly common physiological disorder in pomegranates during cold storage. Although several approaches have been investigated to mitigate the CI symptoms among some pomegranate cultivars, the fundamental and crucial environmental factor — the precise storage temperature for the 'Mengzi' cultivation remains unknown. This research evaluated the impact of storage temperatures of 0, 1, 2, 3, and 4 °C on the post-harvest quality of pomegranates. Results indicated that pomegranates stored at 2 °C exhibited the slightest color change and browning index. After storage of 130 d, pomegranates stored at 2 °C exhibited the lower CI index (82.79% reduction) and the lowest decay incidence (24.68% reduction) compared to those stored at 0 °C. The respiratory rate of pomegranates (2 °C) was also evidently suppressed (16.60%), along with a reduction in weight loss (3.46%). Furthermore, pomegranates stored at 2 °C exhibited the lowest activities of polyphenol oxidase (PPO) and peroxidase (POD), accompanied by the highest total phenolic content, which contributed to a reduction in malondialdehyde (MDA) accumulation. Relatively higher concentrations of soluble solids and titratable acid, as well as a higher sensory evaluation, were found in pomegranates stored at 2 °C. Consequently, it was inferred that the optimal temperature maintained cell membrane integrity modulated normal respiratory metabolism, and oxidative balance, and therefore alleviated CI and deterioration. This report can provide the guiding significance for the long-term storage of 'Mengzi' pomegranates under the condition of precise temperature control in phase temperature storage.

Marselan wine, one of the most important wines in the Ningxia Hui Autonomous Region of China, has attracted much attention due to its unique quality. This study focused on determining and analyzing the changes in volatile flavor compounds and antioxidant activity during different stages of Marselan winemaking. A total of 40 volatile aroma compounds were identified by headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS). Among these compounds, ethyl hexanoate, isoamyl acetate, ethyl formate, ethyl acetate, ethyl butanoate, ethyl octanoate, 3-methyl-1-butanol, ethanol, and 2-methyl-1-propanol showed significant increases after fermentation. Flavonoid and phenol contents in Marselan wine samples also significantly increased after fermentation, demonstrating high antioxidant capacity. Principal component analysis (PCA) successfully distinguished the fruit juice processing stage, alcohol fermentation stage, and malolactic fermentation stage, while the malolactic fermentation stage and wine stable stage could not be distinguished, This indicates that the formation of aroma profiles primarily occurs during the malolactic fermentation stage. The study successfully established flavor fingerprints of samples from different stages of Marselan wine production based on the detected volatile compounds.

Marselan wine, one of the most important wines in the Ningxia Hui Autonomous Region of China, has attracted much attention due to its unique quality. This study focused on determining and analyzing the changes in volatile flavor compounds and antioxidant activity during different stages of Marselan winemaking. A total of 40 volatile aroma compounds were identified by headspace-gas chromatography-ion mobility spectrometry (HS-GC-IMS). Among these compounds, ethyl hexanoate, isoamyl acetate, ethyl formate, ethyl acetate, ethyl butanoate, ethyl octanoate, 3-methyl-1-butanol, ethanol, and 2-methyl-1-propanol showed significant increases after fermentation. Flavonoid and phenol contents in Marselan wine samples also significantly increased after fermentation, demonstrating high antioxidant capacity. Principal component analysis (PCA) successfully distinguished the fruit juice processing stage, alcohol fermentation stage, and malolactic fermentation stage, while the malolactic fermentation stage and wine stable stage could not be distinguished, This indicates that the formation of aroma profiles primarily occurs during the malolactic fermentation stage. The study successfully established flavor fingerprints of samples from different stages of Marselan wine production based on the detected volatile compounds.

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.

Vibrational spectroscopy is a green, rapid, and affordable analytical tool for analysing the quality, safety, and origin of biological materials in agri-food sectors. Pre-processing spectral data is crucial to removing instrumental interferences and physical artifacts when developing a classification model. However, there has yet to be a consensus on which spectral pre-processing method, settings, and decision parameters to use to optimise pre-processing for different spectroscopy tools. Using an arbitrary criterion poses a risk of applying the wrong type or too severe pre-processing that removes valuable information or affects the model's performance for prediction studies. Matthew's Correlation Coefficient (MCC) - a statistic for parameterising classification performance, accounts for data set imbalance and improved decisions on model selection to express uncertainty on future predictions. Four vibrational spectroscopy instruments [near-infrared (NIR), hyperspectral (HSI), mid-infrared (FTIR), and Raman] were compared using different pre-processing methods to understand the performance using MCC to classify coffee from four countries (Indonesia, Ethiopia, Brazil and Rwanda). Key decision parameters were evaluated for the development of reliable classification models. The best pre-processing for NIR was extended multiplicative scatter correction with mean centering (MNCN), and for HSI, Savitzky-Golay (1st derivative, 15 points) with MNCN. NIR performed the best across all four instruments, with FTIR performing the worst. Raman showed potential for coffee origin classification using the right pre-processing. Pre-processing with weighted least squares, normalisation, and MNCN eliminated the fluorescence effect on Raman spectral data. These findings show the feasibility of using MCC for classification problems.

Vibrational spectroscopy is a green, rapid, and affordable analytical tool for analysing the quality, safety, and origin of biological materials in agri-food sectors. Pre-processing spectral data is crucial to removing instrumental interferences and physical artifacts when developing a classification model. However, there has yet to be a consensus on which spectral pre-processing method, settings, and decision parameters to use to optimise pre-processing for different spectroscopy tools. Using an arbitrary criterion poses a risk of applying the wrong type or too severe pre-processing that removes valuable information or affects the model's performance for prediction studies. Matthew's Correlation Coefficient (MCC) - a statistic for parameterising classification performance, accounts for data set imbalance and improved decisions on model selection to express uncertainty on future predictions. Four vibrational spectroscopy instruments [near-infrared (NIR), hyperspectral (HSI), mid-infrared (FTIR), and Raman] were compared using different pre-processing methods to understand the performance using MCC to classify coffee from four countries (Indonesia, Ethiopia, Brazil and Rwanda). Key decision parameters were evaluated for the development of reliable classification models. The best pre-processing for NIR was extended multiplicative scatter correction with mean centering (MNCN), and for HSI, Savitzky-Golay (1st derivative, 15 points) with MNCN. NIR performed the best across all four instruments, with FTIR performing the worst. Raman showed potential for coffee origin classification using the right pre-processing. Pre-processing with weighted least squares, normalisation, and MNCN eliminated the fluorescence effect on Raman spectral data. These findings show the feasibility of using MCC for classification problems.

Plant seeds from the Fabaceae (Leguminosae) family are commonly edible. However, little has been done to study the phytochemicals of red clover (Trifolium pratense) seeds. Our study aims to obtain comprehensive and novel findings on red clover seeds and supercritical fluid extraction (SFE)-extracted oil, with the purpose of exploring their potential as a new source of functional ingredients for food and health care products. In our study, red clover seed oil was extracted by supercritical CO2. Forty-four phytochemical compounds were preliminarily identified in red clover seeds and the extracted oil by UPLC-ESI-MS/MS metabolomics method. These compounds mainly belong to lipids, phenolic compounds, terpenoids and phytosterols. Red clover seeds contain fatty acids (4,676.1 mg/100 g dried seeds) and bioactive components such as phenolic compounds (228.4 mg/100 g) and tocopherols (94.9 mg/100 g). In red clover seed oil, unsaturated fatty acids are over 83% and are rich in linoleic acid (54.7 g/100 g oil) and oleic acid (14.0 g/100 g oil). These findings provide important guidance for introducing red clover seed oil into pharmaceutical products or as functional foods.

Plant seeds from the Fabaceae (Leguminosae) family are commonly edible. However, little has been done to study the phytochemicals of red clover (Trifolium pratense) seeds. Our study aims to obtain comprehensive and novel findings on red clover seeds and supercritical fluid extraction (SFE)-extracted oil, with the purpose of exploring their potential as a new source of functional ingredients for food and health care products. In our study, red clover seed oil was extracted by supercritical CO2. Forty-four phytochemical compounds were preliminarily identified in red clover seeds and the extracted oil by UPLC-ESI-MS/MS metabolomics method. These compounds mainly belong to lipids, phenolic compounds, terpenoids and phytosterols. Red clover seeds contain fatty acids (4,676.1 mg/100 g dried seeds) and bioactive components such as phenolic compounds (228.4 mg/100 g) and tocopherols (94.9 mg/100 g). In red clover seed oil, unsaturated fatty acids are over 83% and are rich in linoleic acid (54.7 g/100 g oil) and oleic acid (14.0 g/100 g oil). These findings provide important guidance for introducing red clover seed oil into pharmaceutical products or as functional foods.

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.

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.

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.

The impact of microwave-assisted thermal sterilization (MATS) on three natural pigments and their storage stability in vegetable purees was investigated. We selected carrot puree for beta carotene, red cabbage puree for anthocyanins, and red beetroot puree for betalains. The purees were packaged in multilayer flexible pouches of AlOx-coated PET (12 μm)//AlOx-coated PET (12 μm)//AlOx-coated PET (12 μm)//ONy (15 μm)//CPP (70 μm), then processed with the MATS system to Fo = 6 to 11 min. After MATS treatment, the pouches were stored for 6 months at a storage temperature of 37.8 °C. The MATS treatment had a significant impact (p < 0.05) on the instrumental colors of three purees, with the total color difference (ΔE) ranging between 6.0 and 10.5. Similarly, the concentration of betalains experienced degradation by 20%−29% after the MATS treatment, while beta-carotene concentration showed a high retention. In addition, the pH of the purees declined considerably (p < 0.05) after the MATS treatment. Over the 6 months of storage at 37.8 °C, the PET-metal oxide pouches maintained the moisture content in all the purees, as the weight loss was only 0.43%−0.45%. The pigments in the MATS-processed purees had different levels of stability; ΔE values varied between 4.23 and 12.3. Beta-carotene was the most stable pigment, followed by betalains and anthocyanins. The degradation of both betalains and anthocyanins during storage was explained by first and fractional conversion models. MATS processing and packages with high gas barriers can therefore be used to preserve selected vegetable purees rich in natural pigments.

The impact of microwave-assisted thermal sterilization (MATS) on three natural pigments and their storage stability in vegetable purees was investigated. We selected carrot puree for beta carotene, red cabbage puree for anthocyanins, and red beetroot puree for betalains. The purees were packaged in multilayer flexible pouches of AlOx-coated PET (12 μm)//AlOx-coated PET (12 μm)//AlOx-coated PET (12 μm)//ONy (15 μm)//CPP (70 μm), then processed with the MATS system to Fo = 6 to 11 min. After MATS treatment, the pouches were stored for 6 months at a storage temperature of 37.8 °C. The MATS treatment had a significant impact (p < 0.05) on the instrumental colors of three purees, with the total color difference (ΔE) ranging between 6.0 and 10.5. Similarly, the concentration of betalains experienced degradation by 20%−29% after the MATS treatment, while beta-carotene concentration showed a high retention. In addition, the pH of the purees declined considerably (p < 0.05) after the MATS treatment. Over the 6 months of storage at 37.8 °C, the PET-metal oxide pouches maintained the moisture content in all the purees, as the weight loss was only 0.43%−0.45%. The pigments in the MATS-processed purees had different levels of stability; ΔE values varied between 4.23 and 12.3. Beta-carotene was the most stable pigment, followed by betalains and anthocyanins. The degradation of both betalains and anthocyanins during storage was explained by first and fractional conversion models. MATS processing and packages with high gas barriers can therefore be used to preserve selected vegetable purees rich in natural pigments.