Inhibited Polyphenol Oxidase Activity Research Articles

Identification of natural inhibitors targeting polyphenol oxidase through machine learning-assisted virtual screening and investigation of molecular mechanisms using multispectral experiments

The development of potent inhibitors of polyphenol oxidase (PPO) is crucial for preventing enzymatic browning, especially when derived from natural food ingredients. However, there are currently few natural PPO inhibitors available, and the underlying structure-activity relationship remains unclear. In this study, a quantitative structure-activity relationship (QSAR) model utilizing machine learning (ML) was developed and integrated with molecular docking to screen for potential PPO inhibitors from a database of over 70,000 food compounds. Subsequently, 17 structurally diverse compounds were validated through experiments, and it was found that 16 of them could inhibit PPO activity at micromolar concentrations, with ε-viniferin demonstrating the most potent inhibitory effect on PPO at 3.69 μM. Furthermore, some molecular fingerprints that may significantly contribute to PPO inhibitors have been discovered through structure-based analysis. Ultimately, the molecular mechanism was elucidated through a series of enzyme kinetics and multispectral experiments. This study aims to promote the diverse development and widespread application of natural PPO inhibitors in industrial production in the future.

Effect of Menthol Treatment on the Sprouting and Quality of Potato Tuber

This study used Dutch potatoes at the end of dormancy as a material to explore the impact of menthol (0.2 and 0.5 g/kg based on potato mass) treatment on sprouting inhibition and potato quality. The findings revealed that a menthol concentration of 0.5 g/kg effectively inhibited potato tuber sprouting and significantly reduced glucoside alkaloid production. After a storage period of 15 days, the sprouting percentage and glucoside alkaloid content of potatoes treated with 0.5 g/kg menthol were observed to be significantly lower at 4.17% and 68.63 mg/kg, respectively, compared to the control group which exhibited values of 100% and 282.01 mg/kg, respectively (p < 0.05). Throughout the storage period, 0.5 g/kg of menthol promoted respiration, reduced malondialdehyde production in potatoes, inhibited polyphenol oxidase activity, and slowed down tissue browning. Additionally, it mitigated the decline in starch and soluble protein content, inhibiting the accumulation of reducing sugars.

Characterization of Sodium Alginate‐Based Edible Active Coating Incorporated with Dendrobium officinale Polysaccharides and Its Application in Grape Packaging

AbstractIn the present study, Dendrobium officinale polysaccharides (DOPs) are incorporated into sodium alginate (SA) for the development of SA‐DOPs films. The physical, mechanical, and functional properties of SA‐DOPs composite films and their ability to preserve fresh grapes are investigated. The results reveal that the addition of DOPs can significantly enhance the thickness, swelling ratio, tensile strength, elongation at break, and thermal stability of the films (p < 0.05) whereas the water solubility and water vapor permeability are decreased. Fourier transform‐infrared (FT‐IR) spectroscopy results reflect interaction of chemical groups and bonds between SA and DOPs. The result of scanning of electron microscopy (SEM) indicates smooth for SA‐DOPs films while control film exhibits rough. The SA‐DOPs films exhibit potential antioxidant effects on 1,1‐diphenyl‐2‐picrylhydrazyl (DPPH) and 2,2'‐azino‐bis(3‐ethylbenzothiazoline‐6‐sulfonic acid) (ABTS) free radicals. Furthermore, the composite films exhibit remarkable inhibition of the growth of Escherichia coli and Staphylococcus aureus (p < 0.05). In addition, the SA‐DOPs coatings can effectively reduce weight loss, inhibit polyphenol oxidase activity, extend the shelf life of the grapes at room temperature (25 ± 1 °C) for 14 days. These results indicate that the SA‐DOPs edible coatings might be a promising candidate in food preservation industries.

Enhancement of quality and self-defense capacity of Agaricus bisporus by UV-C treatment.

Agaricus bisporus (A. bisporus) with completely white appearance are popular with consumers. However, A. bisporus are easily senescence and spoilt, which results in browning and oxidative tissue damage with limited shelf life. This study investigated the effects of shortwave ultraviolet (UV-C, 1.0 kJ m-2 ) irradiation on quality features, enzymatic browning, defense properties of A. bisporus stored at 4 °C for 21 d. After storage, UV-C irradiated A. bisporus had increased quality on sensory, color, hardness, exhibited higher content in total phenolic, brown melanin precursors, including γ-glutaminyl-4-hydroxybenzene (GHB), γ-glutaminyl-3,4-dihydroxybenzene (GDHB) and tyrosine content, lower accumulation of malondiadehyde (MDA), hydrogen peroxide (H2 O2 ), superoxide radical (O2 •¯ ) and maintained membrane integrity in comparison to control samples. Besides, A. bisporus treated by UV-C showed lower degree of browning and higher level of self-defense capacity which may be ascribed to the enhancement in activities of superoxide dismutase (SOD), catalase (CAT), phenylalanine ammonia lyase (PAL), Chitinase (CHT), β-1, 3 glucanase activity (GLU) and inhibiting the activities of polyphenol oxidase (PPO) during the storage. These results indicated that the higher self-defense capacity with UV-C treatment might be the mechanism associated with the delay of senescence in Agaricus bisporus. Therefore, the UV-C treatment is suggested as a potential practical application in mushrooms. This article is protected by copyright. All rights reserved.

Characterization of Polyphenol Oxidase from Eruca sativa

Enzymatic browning reactions by polyphenol oxidases cause alteration of appearance, flavor and nutritive value of vegetables and fruits. It is one of the important problems for vegetables used as salads and causes lots of economic losses. In this study, polyphenol oxidase (PPO) from Eruca sativa was extracted and characterization studies were carried out. Substrate specificity for variable substrates, optimum pH, optimum temperature, effect of different metal ions were assayed. Km and Vmax values were determined as for pyrocatechol Km = 10.24 mM, Vmax = 0.0018 U min-1, catechin; Km = 12.57 mM, Vmax = 0.0012 U min-1, gallic acid; Km = 23.07 mM, Vmax = 0.0001 U min-1. Optimum pH and temperature were determined as pH:7.0 and 20 oC respectively. Effect of various metal ions such as, K+, Fe2+, Mg2+, Zn2+, Cu2+ and Hg2+ on enzyme activity were measured. K+, Mg2+, Zn2+, Cu2+ ions inhibited PPO activity significantly. However Fe2+ ion did not inhibit PPO activity.

Pre-cut L-cysteine treatment inhibited the browning of fresh-cut apples by regulating enzyme activities and amino acid levels

This work investigated the effect of pre-cut L-cysteine treatment on the browning of fresh-cut apple slices. The results showed that 1% L-cysteine pre-cut treatment for 15 min could significantly inhibit the browning and extend the shelf life of fresh-cut apple slices. Pre-cut L-cysteine treatment was found to significantly inhibit polyphenol oxidase (PPO) activity and its gene expression, and increased superoxide dismutase (SOD) and catalase (CAT) activity as well as DPPH radical scavenging rate. In addition, pre-cut L-cysteine treatment improved the content of total and individual phenolics, particularly the content of chlorogenic acid and epicatechin in pulp. Pre-cut L-cysteine treatment also increased the cysteine, glutamic acid, serine and leucine level in pulp and peel. Therefore, pre-cut L-cysteine treatment is an effective method to control the browning of fresh-cut apple by inhibiting PPO activity, improving antioxidant ability and regulating the synthesis of phenolics and free amino acids.

Ozone micro-nano bubble water preserves the quality of postharvest parsley

The production and use of ozone micro-nano bubble water (O3-MNBW) is an innovative technology that prolongs the reactivity of aqueous-phase ozone and maintains the freshness and quality of fruits and vegetables by removing pesticides, mycotoxins, and other contaminants. The quality of parsley treated with different concentrations of O3-MNBW was investigated during storage at 20 ℃ for 5 d, and found that a ten-minute exposure of parsley to 2.5 mg·L−1 O3-MNBW effectively preserved the sensory quality of parsley, and resulted in lower weight loss, respiration rate, ethylene production, MDA levels, and a higher level of firmness, vitamin C, and chlorophyll content, relative to untreated parsley. The O3-MNBW treatment also increased the level of total phenolics and flavonoids, enhanced peroxidase and ascorbate peroxidase activity, and inhibited polyphenol oxidase activity in stored parsley. Five volatile signatures identified using an electronic nose (W1W, sulfur-compounds; W2S, ethanol; W2W, aromatic- and organic- sulfur compounds; W5S, oxynitride; W1S, methane) exhibited a significant decrease in response to the O3-MNBW treatment. A total of 24 major volatiles were identified. A metabolomic analysis identified 365 differentially abundant metabolites (DMs). Among them, 30 and 19 DMs were associated with characteristic volatile flavor substance metabolism in O3-MNBW and control groups, respectively. The O3-MNBW treatment increased the abundance of most DMs related to flavor metabolism and reduced the level of naringin and apigenin. Our results provide insight into the mechanisms that are regulated in response to the exposure of parsley to O3-MNBW, and confirmed the potential use of O3-MNBW as a preservation technology.

Harpin enhances antioxidant nutrient accumulation and decreases enzymatic browning in stored soybean sprouts

Abstract Enzymatic browning causes quality losses in the soybean sprout industry. Herein, the effects of harpin, a proteinaceous bacterial elicitor isolated from Erwinia amylovora, in regulating enzymatic browning and antioxidant nutrient accumulation in stored soybean sprout were investigated. Enhanced soybean sprout growth (evaluated by sprout length and fresh weight) occurred after spraying three times (0, 2, and 4 days after sowing) with 30 mg L−1 harpin during the growth stage. The decline in vitamin C and total phenolic contents and total antioxidant capacity (evaluated by Fe3+ reducing power) were attenuated by harpin during storage. Harpin increased phenylalanine ammonia-lyase, NADPH oxidase (NOX), superoxide dismutase, and catalase activities and inhibited polyphenol oxidase activity and enzymatic browning in soybean sprouts during storage. However, this harpin-promoted sprout growth, enhanced antioxidant accumulation and enzyme activity and improved sprout quality could be partly, but drastically, abolished using diphenyleneiodonium chloride, a specific inhibitor of NOX. Moreover, the mechanisms by which harpin influences antioxidant accumulation and enzymatic browning in soybean sprouts during storage were discussed from the perspective of NOX-mediated H2O2 signalling.

Glutamic acid can prevent the browning of fresh-cut potatoes by inhibiting PPO activity and regulating amino acid metabolism

Enzymatic browning during fresh cutting and storage affects the quality and commodity value of fresh-cut potatoes. The study investigated the effects of glutamic acid (Glu) on browning of fresh-cut potatoes. The results showed that Glu treatments significantly reduced the browning of potato pulp and shreds. Treated with the optimum concentration of 15 g/L Glu for 4 min prolonged the shelf-life of fresh-cut shredded potatoes to 5 d at 2–4 °C. Further research revealed that Glu treatment could inhibit the content of the total phenols, regulate the content of 16 free amino acids and repress the activity of polyphenol oxidase (PPO) via lowering pH value and chelating Cu2+. Molecular docking indicates that Glu stable bound to the active site of PPO. These results indicates that Glu treatment can inhibit the browning of fresh-cut potatoes by inhibiting PPO activity and the total phenolic content and regulating amino acid metabolism.

Recent Advances of Polyphenol Oxidases in Plants

Polyphenol oxidase (PPO) is present in most higher plants, but also in animals and fungi. PPO in plants had been summarized several years ago. However, recent advances in studies of PPO in plants are lacking. This review concludes new researches on PPO distribution, structure, molecular weights, optimal temperature, pH, and substrates. And, the transformation of PPO from latent to active state was also discussed. This state shift is a vital reason for elevating PPO activity, but the activation mechanism in plants has not been elucidated. PPO has an important role in plant stress resistance and physiological metabolism. However, the enzymatic browning reaction induced by PPO is a major problem in the production, processing, and storage of fruits and vegetables. Meanwhile, we summarized various new methods that had been invented to decrease enzymatic browning by inhibiting PPO activity. In addition, our manuscript included information on several important biological functions and the transcriptional regulation of PPO in plants. Furthermore, we also prospect some future research areas of PPO and hope they will be useful for future research in plants.

New Insights into the Inhibition of Hesperetin on Polyphenol Oxidase: Inhibitory Kinetics, Binding Characteristics, Conformational Change and Computational Simulation.

The inhibitory activity of hesperetin on polyphenol oxidase (PPO) and their interaction characteristics were investigated using multiple spectroscopic methods and computational simulation. Hesperetin, a mixed inhibitor, reversibly inhibited PPO activity, and its half-maximum inhibitory concentration (IC50) values on monophenolase and diphenolase were 80.8 ± 1.4 μM and 776.0 ± 15.5 μM, respectively. Multivariate curve resolution-alternate least squares (MCR-ALS) analysis suggested PPO interacted with hesperetin and formed PPO-hesperetin complex. Hesperetin statically quenched PPO's endogenous fluorescence, and hydrophobic interactions mainly drove their binding. Hesperetin affected the polarity of the microenvironment around the Trp residues in PPO, but had no effect on that around Tyr residues. Circular dichroism (CD) results showed that hesperetin increased α-helix content and decreased β-fold and random coil contents, thus tightening PPO's structure. Molecular docking showed that hesperetin entered the hydrophobic cavity of PPO, bound near the dinuclear copper active center, interacted with Val283, Phe264, His85, Asn260, Val248, and His263 via hydrophobic interactions, formed hydrogen bonds with Met280, His89, and His259 residues and also interacted with Phe292, His61, Phe90, Glu256, His244, Asn260, Phe264, and Gly281 via van der Waals forces. The molecular dynamics simulation results also demonstrated that the addition of hesperetin reduced the stability and hydrophobicity of PPO and increased PPO's structural denseness. Thus, the inhibition of hesperetin on PPO may be because hesperetin bound near the active center of PPO, interacted with the surrounding residues, occupied the binding site for substrate, and induced the changes in PPO's secondary structure, thus inhibiting the catalytic activity of PPO. This study may provide novel views for the inhibition of hesperetin on PPO and theoretical guidance for developing flavonoids as new and efficient PPO inhibitors.

Inhibitory mechanism of sodium hexametaphosphate on enzymatic browning in yellow alkaline noodles

The effect and mechanism of sodium hexametaphosphate (SHMP) on polyphenol oxidase (PPO) enzymatic browning in yellow alkaline noodles (YAN) were investigated. The browning degree and PPO activity in YAN or PPO solutions decreased with the SHMP concentrations increased. Variations in pH values (pH 7–8.5) adjusted by HCl or acetic acid slightly affected the PPO activity, but SHMP inhibited PPO activity more pronounced. The inhibition of SHMP on PPO activity was irreversible. SHMP formed coordinate covalent bonds with Cu2+ to make PPO inactive. HPLC analysis revealed that SHMP reduced the browning products and led to the color of PPO-catechol systems being lightened. Furthermore, SHMP inhibited browning by hampering the auto-oxidization of intermediate products due to the change in pH value. Besides, the HPLC chromatogram, UV–vis spectrum, and mass spectrometry revealed that SHMP could convert melanin (m/z 248.97, 723.5, and 836.58) to light-colored substances (m/z 137.11).

Metabolomic and transcriptomic analysis reveal high solar irradiance inhibited the melanin formation in persimmon fruit peel

During fruit development of Diospyros kaki cv. ‘Heishi’, the peel color changed to orange-red when undergone high solar irradiance, which was different from turning black in normal condition. Limited information on this phenomenon of persimmon fruit has been reported. In the present study, we explored ‘Heishi’ persimmon fruit under two conditions of extreme solar irradiance during development. Their peel characteristics were evaluated, including organelle ultra-structure, polyphenol oxidase (PPO) activity, transcriptome profile, and metabolomics. The results showed that high solar irradiance severely degraded or ruptured chloroplast, and most of the analyzed metabolites were higher accumulated in high solar irradiance stressed peel than in the normal tissues. Significantly accumulated phenolics and carotenoids may contribute to photoprotection by scavenging high solar irradiance stress triggered ROS products. RNA-Seq analysis showed that many differentially expressed genes (DEGs) related to the accumulation of the analyzed metabolites were up-regulated under stress. The stress also significantly inhibited PPO activity at stages of melanin formation. The reduced melanin and significantly accumulated carotenoids (especially lycopene and β-carotene) finally resulted in orange-red fruit peel.

The Effect of Dielectric Barrier Discharge Plasma Gas and Plasma-Activated Water on the Physicochemical Changes in Button Mushrooms (Agaricus bisporus).

Button mushrooms (Agaricus bisporus) are highly popular worldwide due to their rich nutritional value and health benefits. However, the rapid water loss rate and browning restrict their economic value. The atmospheric cold plasma (ACP) generated by the plasma equipment used by dielectric barrier discharge preservation technology is widely used for food preservation since it is cost-efficient and environmentally friendly, generating no chemical residues. This study established four treatment groups, namely the direct ACP treatment group (DBD), plasma-activated water immersion group (PAW), pure water immersion group (PW), and control group (control), to explore the effect that ACP preservation technology has on button mushrooms. The results indicated that ACP treatment decreased the pH of pure water from 5.90 ± 0.03 to 5.16 ± 0.03, while significantly increasing the temperature (p < 0.05). During the storage period, the browning index (BI) and E value were the lowest in the PAW group, which exhibited the best hardness and sensory properties. Neither the pH nor water activity changed significantly during the storage period in any of the groups. The polyphenol oxidase (PPO) activity in the button mushroom decreased significantly compared with the control after plasma-activated water treatment. In summary, plasma-activated water significantly reduced the BI and E value of button mushrooms, inhibited PPO activity, and yielded the most stable sensory properties for the optimal preservation of button mushrooms.

Effects of different concentrations of ascorbic acid on the stability of (+) – Catechin under enzymatic conditions

A series of incubation systems of (+) - catechin (Cat), ascorbic acid (AA) and polyphenol oxidase (PPO) of lotus rhizome at 40 °C were performed to investigate the effect and oxidation pathway of AA on the stability of Cat. The results showed that after the enzymatic or non-enzymatic oxidation of Cat, the products of the two reactions were the same, namely epicatechin, catechin dimer and dehydrogenated catechin dimer. After adding AA, the protective effect of AA on catechin increased first and then decreased with the increase of AA concentration. 0.1 mmolL(exp)-1 AA can inhibit PPO activity in a short time. Within 24 h, 1 mmolL(exp)-1 AA can keep Cat content at 87.88 %. At the concentration of 10 mmolL(exp)-1 AA, excessive AA is oxidized to form a large amount of dehydroascorbic acid (DHAA), which forms an adduct with Cat, promoting the consumption of Cat. The effect of AA on the stability of Cat is time-dependent and dose-dependent.

A novel anti-browning agent S-furfuryl thioacetate for fresh-cut potato screened from food-derived sulfur compounds

This research aimed to screen out safe and effective inhibitors of enzymatic browning from food-derived sulfur-containing compounds. Among eighteen candidate compounds, three were found to reduce the browning of fresh potato mashes. One of these compounds, S-furfuryl thioacetate (S-Ft) at only 0.04 and 0.07 mM inhibited the browning of fresh potato sticks, for over 10 d at 4 °C with an efficacy close to sodium bisulfite at 2.40 mM. S-Ft also reduced the browning of eggplant and asparagus lettuce slices. S-Ft retarded the browning occurrence of potato mashes and tyrosine solutions, but it did not cause the brown pigments colorless. Both the decrease in tyrosine contents and the increase in quinone contents were slowed by S-Ft in potato mashes. Compared with control, S-Ft at 0.04 and 0.07 mM reduced polyphenol oxidase (PPO) activity by 91.22 % and 91.77 %, and addition of copper acetate recovered the PPO activities to 55.62 % and 59.45 % of control, respectively. Kinetics results showed S-Ft inhibited PPO activity in a reversible mixed-type manner. The data of circular dichroism analysis and fluorescence emission spectra indicated S-Ft treatment caused the decrease in α-helix content, the increase in β-sheet content and the change in secondary structure of PPO. Molecular docking results illustrated S-Ft could act with Cu2+ and amino acid residues of PPO. By comparison with other anti-browning inhibitors, S-Ft has the characteristics of low dosage and long shelf-life extension. These results demonstrated that S-Ft could be a novel and promising enzymatic browning inhibitor by chelating Cu2+ and changing the conformation of enzyme to reduce PPO activity.

Multispectroscopic and computational simulation insights into the inhibition mechanism of epigallocatechin-3-gallate on polyphenol oxidase

Polyphenol oxidase (PPO)-mediated enzymatic browning occurs in fruit, vegetables and aquatic products and causes huge economic losses every year. In this study, epigallocatechin-3-gallate (EGCG) displayed high affinity for and efficient inhibitory capacity against PPO. To explore the inhibition mechanism, multispectroscopic methods and computational simulations were implemented. Initially, EGCG inhibited PPO activity reversibly in a mixed-type manner. Then, the conformation and secondary structure changes of PPO after binding with EGCG were discovered by fluorescence emission spectra and circular dichroism. Molecular docking and dynamic simulation results revealed that EGCG could tightly bind with the binuclear copper domain of PPO through hydrophobic stacking and hydrogen bonds. Moreover, EGCG might act as a linker to interact with different PPO molecules at another binding site. Transmission electron microscopy observation suggested that EGCG induced the aggregation of PPO. Therefore, the inhibition mechanism of EGCG on PPO included competition for catalytic centers and induced aggregation.

Anti-polyphenol oxidase mechanism of oligomeric procyanidins and its application on browning control of “Baiyu” loquat during storage

The harvested loquat fruits are prone to browning, leading to a decline in fruit quality. Inhibiting activity of polyphenol oxidase (PPO) is an important way to prevent browning. In this study, we evaluated the inhibitory impact of oligomeric procyanidins (OPC) on hydroxylation of monophenol and oxidation of o-diphenol catalyzed by PPO and effect of OPC on loquat fruits storage. The obtained results revealed that OPC could attenuate the activity of monophenolase and diphenolase. For monophenolase activity, the inhibition rate was observed to be dose-dependent with an IC50 of 11.6 ± 3.4 μg/mL for the steady-state rate. For diphenolase activity, OPC inhibited PPO activity (IC50 = 15.75 ± 2.1 μg/mL) with a reversible and competitive mechanism and quenched fluorescence of PPO by forming OPC-PPO complex with one binding site in a static procedure. In addition, the data obtained from storage assays revealed that OPC could enhance the quality of harvested loquat fruits by attenuating the PPO activity, augmenting the content of total phenolics and flavonoids, and simultaneously delaying the browning of loquats. In this research, we identified a potent PPO inhibitor and expanded its potential as a food preservative.

Effects of Enzymatic Browning and Leaf Browning Inhibitors on Tobacco

The maturity of fresh tobacco leaves affects the browning of leaves to differing degrees during the curing process, thus affecting the quality of cured tobacco leaves. In this study, tobacco leaves of increasing maturity (M1–M4) were selected. Dark-box experiments were performed to investigate the roasting characteristics and relationship between tobacco leaf maturity and browning and to determine their polyphenol oxidase (PPO) activities and qualities. We found that mature tobacco leaves (M3) had high substance accumulation, and the PPO activity decreased throughout the baking process. After 72 h of curing, the PPO activity in the M3 leaves was 81.22 U/g, which was significantly different from that in M1 and M2. On this basis, three different browning inhibitors (control: 10 mL of distilled water; T1:10 mL of 0.5% citric acid+0.5% polyphenol; and T2:10 mL 0.5% citric acid+0.5% salicylic acid) were sprayed onto the surface of M2 leaves before curing to observe their inhibitory effects. The T2-treated leaves showed inhibited PPO activity, and after baking for 72 h, the peroxidase enzyme (POD) content of the T2-treated leaves was higher, which effectively inhibited the enzymatic reaction. In conclusion, to reduce the browning ratio of tobacco leaves during the curing process, the harvested tobacco leaves should be allowed to reach full maturity when the values of Soil Plant Analysis Development (SPAD) chlorophyll meter ranged 9–13, and 0.5% citric acid+0.5% salicylic acid (T2) should be used as a browning inhibitor to produce tobacco with the highest sensory quality. The results of this study can help inhibit browning and maintaining the quality of the tobacco leaves during the curing process.

Effect of Chitosan Composite Coatings with Salicylic Acid and Titanium Dioxide Nanoparticles on the Storage Quality of Blackcurrant Berries

The use of chitosan and chitosan composite coatings for the preservation of fruits and vegetables during storage is attracting increasing attention. In this study, a chitosan-based edible coating, as well as a second chitosan-based edible coating containing salicylic acid (CTS + SA), a third containing nanosized titanium dioxide particles (CTS + TiO2), and a fourth containing a combination of these two (CTS + SA + TiO2) were evaluated in terms of their effects on the postharvest quality of blackcurrant fruit during storage at 4 °C. The results showed that compared with the other three treatment groups, the blackcurrants treated with CTS + SA + TiO2 underwent the smallest changes in weight loss, total soluble solids, titratable acidity, vitamin C, and total anthocyanin content, and retained the highest total flavonoid content. This combined treatment significantly inhibited polyphenol oxidase activity during storage, and the CTS + SA + TiO2 samples also displayed the lowest malondialdehyde content. These results, thus, indicate that the CTS + SA + TiO2 composite coating could maintain the nutrient composition of blackcurrants, thereby playing a significant role in preserving the quality of this fruit at 4 °C.