Purple Sweet Potato Anthocyanins Research Articles

Recent Advances in Purple Sweet Potato Anthocyanins: Extraction, Isolation, Functional Properties and Applications in Biopolymer-Based Smart Packaging.

Petroleum-based plastic packaging materials have negative impacts on the environment and food safety. Natural biopolymer-based food packaging materials are the proper substitutes for plastic-based ones, which is because biopolymers are nontoxic, biodegradable and even edible. The incorporation of bioactive and functional substances into a biopolymer-based film matrix can produce novel smart packaging materials. Anthocyanins, one class of natural colorants with potent antioxidant activity and pH-response color-changing ability, are suitable for producing biopolymer-based smart packaging films. The purple sweet potato is a functional food rich in anthocyanins. In the past decade, numerous studies have reported the extraction of anthocyanins from purple sweet potato and the utilization of purple sweet potato anthocyanins (PSPAs) in biopolymer-based smart packaging film production. However, no specific review has summarized the recent advances on biopolymer-based smart packaging films containing PSPAs. Therefore, in this review, we aim to systematically summarize the progress on the extraction, isolation, characterization, purification and functional properties of PSPAs. Moreover, we thoroughly introduce the preparation methods, physical properties, antioxidant and antimicrobial activity, pH sensitivity, stability and applications of biopolymer-based smart packaging films containing PSPAs. Factors affecting the extraction and functional properties of PSPAs as well as the properties of biopolymer-based films containing PSPAs are discussed.

Preparation of chitosan/polyvinyl alcohol antibacterial indicator composite film loaded with AgNPs and purple sweet potato anthocyanins and its application in strawberry preservation

This study incorporated purple sweet potato anthocyanin (PSPA) and silver-nanoparticles (AgNPs) into the chitosan/polyvinyl alcohol film matrix (PVA/CS) to successfully prepare a composite film, which effectively inhibited bacterial growth and indicated product freshness. The addition of AgNPs and PSPA led to a dense structure of the film, which effectively enhanced its physical properties, barrier properties and functional properties. The incorporation of PSPA made the composite film highly pH-sensitive, which exhibited distinct color changes in varying pH solutions. The PVA/CS-AgNPs-PSPA10 composite film with PSPA and AgNPs resulted the shelf life of strawberries to 13 days at 4 °C, which effectively reduced strawberry breathing during storage. Additionally, such composite film changed color from purple to yellow-purple, indicating the deterioration of strawberries. It also showed an antibacterial indication through its excellent antibacterial property and freshness indication performance, which demonstrated its significance in developing antibacterial indicator composite packaging materials for fruits and vegetables preservation.

Sweet potato protein hydrolysates solidified calcium-induced alginate gel for enhancing the encapsulation efficiency and long-term stability of purple sweet potato anthocyanins in beads

Based on the previous research, this work aimed to reveal the effect of sweet potato protein hydrolysates (SPPHs) with different molecular weights (1000, 3000, and 8000 Da) at 0.5 % on the gelation behavior of calcium-induced sodium alginate (SA), and the encapsulation efficiency and storage stability of purple sweet potato anthocyanins (PSPA) in calcium-induced alginate gel beads was determined. Results indicated that SPPHs with a molecular weight of 8000 Da formed hydrogen bonds and other interactions with SA, which strengthened the internal network connections of the gel, significantly enhanced the gel and effectively filled its pores. The highest encapsulation efficiency was achieved at 87.27 %, compared to 61.73 % without SPPHs. Additionally, stored at 37 °C for 21 days after commercial sterilization, the residual concentration of PSPA with SPPHs was 2.50 times higher than that without SPPHs. SPPHs can enhance the encapsulation efficiency of PSPA and retard their release in gel beads.

Preparation and characterization of intelligent and active bi-layer film based on carrageenan/pectin for monitoring freshness of salmon

This work aimed to develop and characterize a novel bi-layer film (BIF) for monitoring the freshness of salmon. The indicator layer consists of carrageenan (Car), pectin (PEC) and purple sweet potato anthocyanin (PSPA), and the antibacterial layer consists of Car and magnolol (Mag). The results showed that the Car/Mag2 had the optimal water resistance: the static water contact angle of 80.36 ± 0.92 °, moisture content of 31.38 ± 0.86 %, swelling degree of 92.96 ± 0.46 %, and water solubility of 40.08 ± 1.17 %, and showed excellent antibacterial properties against E. coli and S. aureus with antibacterial rate of 86.13 % ± 0.10 % and 97.53 % ± 0.02 %, respectively. Then BIFs with different PSPA concentration were tested. The morphology, mechanical and water vapor properties (WVP) of the BIFs were studied, and its application in salmon preservation was evaluated. The mechanical properties and WVP test results showed that the BIF0.2 had the optimal Tensile strength (TS) and WVP values. The BIFs showed distinguishable color changes between the pH ranges of 3–10. The shelf life of salmon packaged by BIF0.2 was prolonged by 2 days. Moreover, the BIF0.2 was able to effectively monitor salmon freshness. In conclusion, the BIF has great potential for monitoring salmon meat freshness.

Fabrication of multifunctional ethyl cellulose/gelatin-based composite nanofilm for the pork preservation and freshness monitoring

In this study, an active and intelligent nanofilm for monitoring and maintaining the freshness of pork was developed using ethyl cellulose/gelatin matrix through electrospinning, with the addition of natural purple sweet potato anthocyanin. The nanofilm exhibited discernible color variations in response to pH changes, and it demonstrated a higher sensitivity towards volatile ammonia compared with casting film. Notably, the experimental findings regarding the wettability and pH response performance indicated that the water contact angle between 70° and 85° was more favorable for the smart response of pH sensitivity. Furthermore, the film exhibited desirable antioxidant activities, water vapor barrier properties and also good antimicrobial activities with the incorporation of ε-polylysine, suggesting the potential as a food packaging film. Furthermore, the application preservation outcomes revealed that the pork packed with the nanofilm can prolong shelf life to 6 days, more importantly, a distinct color change aligned closely with the points indicating the deterioration of the pork was observed, changing from light pink (indicating freshness) to light brown (indicating secondary freshness) and then to brownish green (indicating spoilage). Hence, the application of this multifunctional film in intelligent packaging holds great potential for both real-time indication and efficient preservation of the freshness of animal-derived food items.

Wheat Protein Hydrolysates Improving the Stability of Purple Sweet Potato Anthocyanins under Neutral pH after Commercial Sterilization at 121 °C.

Anthocyanins are prone to degradation and color fading after sterilization. This work examined the potential of wheat protein hydrolysates (WPHs, 40 g/L) in improving the stability of purple sweet potato anthocyanins (PSPAs) under a pH of 6.8 after sterilization at 121 °C followed by storage. Results showed that WPHs increased the thermal degradation half-life of PSPAs 1.65 times after sterilization. Compared to PSPAs alone, after being stored at 37 °C and 45 °C for 7 days, the retention concentration of PSPAs with WPHs was 5.4 and 32.2 times higher, and the color change of PSPAs with WPHs decreased from 6.19 and 10.46 to 0.29 and 0.77, respectively. AFM data, fluorescence and UV spectrograms indicated the formation of complexes between PSPAs and WPHs by hydrophobic attraction confirmed by zeta-potential data. PSPAs with WPHs had stable particle size and zeta potential, which may also significantly increase the concentrations after digestion and antioxidant power of PSPAs. This work indicated that the assembled PSPAs composite structure by WPHs significantly reduced the degradation of PSPAs at a pH of 6.8 after sterilization at 121 °C followed by long-term storage.

Pre-Treatment, Extraction Solvent, and Color Stability of Anthocyanins from Purple Sweetpotato.

Purple sweetpotato anthocyanins (PSPA) exhibit significant potential as food colorants with associated health benefits. However, challenges related to browning and instability have hindered the application of PSPA. In this study, various pre-treatments and solvents for PSPA extraction were evaluated based on color, anthocyanin yields, antioxidant capabilities, and brown index. Browning markedly influenced the color and reduced the antioxidant capacity. Optimal results were obtained with the pre-treatment of "steaming of unpeeled whole sweetpotato" and the solvent "1% citric acid-ddH2O". Furthermore, the color stability of purified PSPA solutions was evaluated under pH levels from 1 to 13 at 25 °C and 65 °C. The PSPA solutions showed a color spectrum from magenta, blue/green, and then to yellow across the pH range. The blue/green hues at pH 10-12 rapidly degraded, while the magenta hue at lower pH showed higher color stability. Elevated temperatures significantly accelerated the PSPA degradation. However, PSPA solutions at pH 1-2 exhibited remarkable color stability, with no spectral decay at either 65 °C for 12 h or 25 °C for 32 days. These results provide valid guidance for the extraction, preservation, and application of PSPA in the food industry.

Edible colorimetric label based on immobilized purple sweet potato anthocyanins onto edible film for packaged mushrooms freshness monitoring.

An edible colorimetric label has been developed to determine the freshness level of mushrooms, i.e. white oyster mushrooms (Pleurotus ostreatus). The edible indicator label has been fabricated based on purple sweet potato (Ipomoea batatas L.) anthocyanins (PSPA) immobilized onto an edible film made of chitosan and cornstarch with added PVA. The freshness parameters of the mushrooms were pH, weight loss, texture, and sensory evaluation. The results showed that the colorimetric label was dark purple when the mushroom was fresh, and turn to light purple when the mushroom was still fresh, and finally green when the mushroom was no longer fresh. The color value (mean Red) of the label was measured using the ImageJ program, where its color value (mean Red) increased with decreasing freshness level of the mushrooms. The edible label can distinguish fresh mushrooms from spoilage, making it suitable to be used in a packaged mushroom as a freshness indicator.

Functional pH-Sensitive Film Containing Purple Sweet Potato Anthocyanins for Pork Freshness Monitoring and Cherry Preservation.

An antioxidative and pH-sensitive multifunctional film, incorporating anthocyanin-rich purple sweet potato extract (PPE) was fabricated from polyvinyl alcohol (PVA) and sodium alginate (SA)/sodium carboxymethyl cellulose (CMC-Na). The film was composed of 6:4 PVA:SA/CMC-Na (mass ratio, SA:CMC-Na at 1:1) with added PPE, and changed color with changes in pH, and also had useful UV-blocking, antioxidant, mechanical, and water vapor barrier properties, which enable its use as a food coating film. In addition, the incorporation of 300 mg PPE increased the biodegradability of the film in soil from 52.47 ± 1.12% to 64.29 ± 1.75% at 17 days. The pH sensitivity of the film enabled its successful use for the evaluation of pork freshness. Cherries coated with the film had an extended shelf life from 3-4 to 7-9 days, during storage at 25 °C. Consequently, the multifunctional film can be applied to packaging for real-time pH/freshness monitoring and for effectively preserving the freshness of meat and fruit.

A Colorimetric Nanofiber Film Based on Ethyl Cellulose/Gelatin/Purple Sweet Potato Anthocyanins for Monitoring Pork Freshness.

In this study, colorimetric indicator nanofiber films based on ethyl cellulose (EC)/gelatin (G) incorporating purple sweet potato anthocyanins (PSPAs) were designed via electrospinning technology for monitoring and maintaining the freshness of pork. The film presented good structural integrity and stability in a humid environment with water vapor permeability (WVP) of 6.07 ± 0.14 × 10-11 g·m-1s-1Pa-1 and water contact angle (WCA) of 81.62 ± 1.43°. When PSPAs were added into the nanofiber films, the antioxidant capacity was significantly improved (p < 0.05) with a DPPH radical scavenging rate of 68.61 ± 1.80%. The nanofiber films showed distinguishable color changes as pH changes and was highly sensitive to volatile ammonia than that of casting films. In the application test, the film color changed from light pink (fresh stage) to light brown (secondary freshness stage) and then to brownish green (spoilage stage), indicating that the nanofiber films can be used to detect the real-time freshness of pork during storage. Meanwhile, it could prolong the shelf life of pork by inhibiting the oxidation degree. Hence, these results suggested that the EC/G/PSPA film has promising future for monitoring freshness and extending shelf life of pork.

Glycated whey protein concentrate for purple sweet potato anthocyanins delivery: Physicochemical stability and in vitro digestion characteristics

Glycated proteins are effective materials for improving the environmental stability and bioavailability of biologically active chemicals. The whey protein concentrate (WPC)-xylose (D) conjugates produced by the Maillard process were used to load and protect purple sweet potato anthocyanins in this study. Response surface optimization was used to determine the best parameters for preparing WPC-D conjugates. Glycation altered the secondary structure of proteins, according to structural studies, which also had an impact on their functional characteristics, which showed better antioxidant activity before and after simulated gastrointestinal (GI) digestion (p < 0.05). In the meantime, when compared to free anthocyanins (ANs) and heat-treatment of WPC-load ANs, WPC-D conjugates significantly improve ANs' stability to storage, thermal, light, metal ion, and hydrogen peroxide, while also increasing bioavailability and antioxidant activity during simulated GI digestion (p < 0.05). The results highlighted that the WPC-D conjugates are functional, promising, and useful hydrophilic bioactive carrier materials.

Alterations in Blaood Profiles and Spleen Tissue Following Purple Sweet Pota-to Anthocyanin Extract Treatment in Restraint-Stressed Mice

Stress is associated with broad changes in blood and immune cell dysfunction, which are correlated with the spleen as a secondary lymphoid organ. Anthocyanin, a plant bioactive compound from purple sweet potatoes, has previously been reported to have a beneficial effect on stress response behavior. However, the limited studies evaluated anthocyanin's effect on blood profiles and spleen tissue under stress. Therefore, this study aimed to explore the effect of total anthocyanin extract (ANC) from purple sweet potatoes (PSP) on the blood profiles and spleen tissue of restraint stressed mice. A total of 20 male adult BALB/c mice were divided into control (CTRL), stress (STR), stress + ANC 10 mg/kgBW (STR+ANC10), stress + ANC 20 mg/kgBW (STR+ANC20), and stress + ANC 40 mg/kgBW (STR+ANC10). Restraint stress was applied two hours/day for 14 days. An automatic blood analyzer was used for blood profiling. Immunoblotting of caspase-3 and hematoxylin-eosin-stained histological slides were observed for spleen tissue analysis. Combination of STR and ANC treatment reduced the erythrocyte count, hemoglobin level, and leucocyte count. The ANC-treated groups had a higher percentage of lymphocytes and a lower percentage of granulocytes. The expression of caspase-3 declined among ANC-treated groups. Spleen extramedullary erythropoiesis, vacuolization, and white pulp involution were demonstrated in stress and ANC-treated animals. In summary, restraint stress modified the blood cell profiles and spleen tissue in the mice model. Further research is necessary to evaluate the mechanism of ANC during stress on blood cells and splenic tissue repair enhancement

Determining role of structure in the stability increase of purple sweet potato anthocyanins bound to proteins

AbstractThe stability of anthocyanins is poor, seriously affecting their biological activity. The effect of bovine serum albumin (BSA) on the stability of purple sweet potato anthocyanins (PSPA) and its mechanism of action was investigated. Eleven anthocyanins in purple sweet potato were identified, and the stability of PSPAs with different structures combined with BSA was analyzed separately. The results showed an interaction between BSA and PSPA by UV absorption and fluorescence spectra, in which PSPA could cause a fluorescence burst of BSA, and the binding of PSPA to BSA was in the form of 1:1. In addition, the interactions are spontaneous, and hydrophobic interactions dominate. The binding amount study showed that 1 mol/L of BSA binds 3 mol/L of PSPA. The results of zeta potential and particle size showed that the absolute value of the possibility was around 30 mV, and BSA could combine with PSPA to form nanoparticles with high stability. Molecular docking analysis showed that PSPA could be well embedded in the structural cavities of BSA. The binding sites were near sites I and II, hydrogen bonding and hydrophobic interactions act as the main drivers of binding. Finally, after binding, BSA could effectively improve the stability of PSPA, especially for different structures of PSPA. The binding of diacylated anthocyanins was more stable than monoacylated ones, peonidin was more stable than cyanidin, and caffeoyl was more stable compared to p‐hydroxybenzoyl and feruloyl.

Identification of Functional Groups and Types of Anthocyanin Pigments of Purple Sweet Potato cv. Antin 2 and cv. Antin 3

Purple sweet potatoes (Ipomoea batatas L. Lam.) contain anthocyanin pigments which act as natural antioxidants which are very beneficial for health. The research aimed to identify the functional groups and types of anthocyanin pigments in purple sweet potato cv. Antin 2 and cv. Antin 3, using FTIR and identification of anthocyanin pigment types using LCMS/MS. The results of FTIR analysis show that the purple sweet potato cultivar Antin 2 has 12 spectrum peaks ranging from wavelengths of 570.48 cm-1 to 3 394.40 cm-1. Functional groups detected include benzene nuclei, hydrocarbons (dominating), carbonyls, carboxyl esters, aromatics, aldehydes, and alcohols. Meanwhile, the purple sweet potato cultivar Antin 3 has 15 spectrum peaks ranging from wavelengths of 417.88 cm-1 to 3 365.86 cm-1. The functional groups detected include core-benzene hydrocarbons, carboxyl esters, methyl, aromatics, carbonyls, carbonyl esters, aldehydes, aldehyde carbons, and hydroxyl carbons. The LCMS/MS identification results of purple sweet potato anthocyanin pigments of the Antin 2 cultivar detected 11 types, including Cyanidin 3-(6“-caffeoyl sophoroside)-5-glucoside and Cyanidin 3-(6“-feruloyl sophoroside)-5-glucoside. In the purple sweet potato cultivar Antin 3, 14 types of anthocyanins were found, including, Malvidin 3-5 diglicoside, Cyanidin 3-(6“-caffeoyl sophoroside)-5-glucoside, Cyanidin, and Cyanidin 3-(6“feruloyl sophoroside)-5-glucoside.

Effects of sunflower pectin on thermal stability of purple sweet potato anthocyanins at different pH

The present study aimed to examine the impact of sunflower pectin (SFP) on the thermal stability and antioxidant activity of purple sweet potato anthocyanins (PSPA) at varying pH levels. It was observed that the pH value significantly influenced the ability of pectin to protect anthocyanins from thermal degradation, which was found to be associated with the rate of binding between PSPA and SFP. The binding rate of PSPA-SFP was observed to be highest at pH 4.0, primarily due to the influence of electrostatic interaction and hydrogen bonding. Monoacylated anthocyanins exhibited a binding rate approximately 2–4 % higher than that of diacylated anthocyanins. The PSPA-SFP demonstrated its highest thermal stability at pH 4.0, with a corresponding half-life of 14.80 h at 100 °C. Molecular dynamics simulations indicated that pectin had a greater affinity for the flavylium cation and hemiketal form of anthocyanins. The antioxidant activity of anthocyanins in PSPA and PSPA-SFP increased with increasing pH, suggesting that anthocyanins at high pH had higher antioxidant activity than anthocyanins at low pH.

Identification of Anthocyanidins in Anthocyanin Extract of Purple Sweet Potato (Ipomoea batatas l), black rice (Oryza sativa l), and Black Glutinous rice (Oryza sativa v. glutinosa)

Anthocyanins originating from different commodities have different constituent components and anthocyanidin levels. This will undoubtedly affect the anthocyanin content of total in foodstuffs. Local items such as; Purple sweet potato, black rice, and black glutinous rice have different structural components and levels of anthocyanidins. The research objective was to measure the total anthocyanin content and identify anthocyanidins qualitatively and quantitatively from anthocyanin extracts of purple sweet potato, black rice, and black glutinous rice. The research method used was an experimental method , qualitative and quantitative identification analyses were carried out using the UHPLC-PDA (Ultra high Performance Liquid Chromatographic) instrument system. Based on the study with pH-difference measurements, the total anthocyanin extract in purple sweet potato is 0.6 mg / g of material, much lower than black rice (5.50 mg / g of material) and black glutinous rice (6.00 mg / g of material). g material). Based on the identification of the purple sweet potato anthocyanin extract, the main components of anthocyanidins were Delfinidin, Cyanidin, and Malvidin with concentrations of 0.12 mg, 0.12 mg, and 1.20mg / 100g of ingredients, respectively. Meanwhile, black rice and black glutinous rice were identified with cyanidine and malvidin with concentrations of 0.73 and 13.17 mg / 100g and 1.07 mg and 17.6 mg / 100g of ingredients.

Effects of shading intensities on the yield and contents of anthocyanin and soluble sugar in tubers of purple sweet potato

AbstractLight intensity is an important factor affecting crop yield and quality. Studies on the effect of light intensity on the synthesis and accumulation of anthocyanin and soluble sugar in purple sweet potato tubers (Ipomea batatas L.) have rarely been documented. In this experiment, the effects of different shading intensities (no shading [L0], 20% shading [L1], 40% shading [L2], 60% shading [L3], and 80% shading [L4]) on the agronomic traits, fresh tuber yield, anthocyanin, and soluble sugar contents of purple sweet potatoes were investigated. Results showed that the fresh tuber yield was not decreased, and the accumulation of anthocyanin and soluble sugars in the tubers was increased under L1 compared to L0; however, these parameters were significantly decreased from L2 to L4 treatments. Further analysis showed that anthocyanin synthase (ANS) may be the restriction enzyme for anthocyanin synthesis in purple sweet potato tubers, and either excessive or insufficient light intensity decreased ANS activity. Results suggested that purple sweet potatoes might be planted in intercropping system with a little insufficient light intensity in tropical areas. However, the mechanisms underlying the effects of shading intensities on the yield and contents of anthocyanin and soluble sugar in tubers of purple sweet potato will be addressed in the future.

Effect of Preheating Whey Protein Concentrate on the Stability of Purple Sweet Potato Anthocyanins.

Anthocyanins (ANs) have strong antioxidant activities and can inhibit chronic diseases, but the instability of ANs limits their applications. The conservation of preheating whey protein concentrate (WPC) on the stability of purple sweet potato ANs was investigated. The retention of ANs in WPC-ANs was 85.88% after storage at 25 °C for 5 h. WPC-ANs had higher retention of ANs in heating treatment. The retention rates of ANs in WPC-ANs exposed to light and UV lamps for 6 h were 78.72% and 85.76%, respectively. When the concentration of H2O2 was 0.50%, the retention rate of ANs in the complexes was 62.04%. WPC-ANs' stability and antioxidant activity were improved in simulated digestive juice. The WPC-ANs connection was static quenching, and the binding force between them was a hydrophobic interaction at one binding site, according to the fluorescence quenching spectroscopy. UV-visible absorption spectroscopy and Fourier transform infrared spectroscopy (FTIR) analysis further indicated that the secondary structure and microenvironment of amino acid residues in WPC can be impacted by the preheating temperature and preheating times of WPC. In conclusion, preheating WPC can successfully preserve the stability of purple sweet potato ANs by binding to them through a non-covalent interaction.

Renoprotective Effects of Anthocyanins Against Uric AcidInstigated Injury: Mini Review with a Special Emphasis on Purple Sweet Potato (Ipomoea batatas L.) Anthocyanins

Anthocyanins are ubiquitous phytoconstituents found in a wide array of natural products. Purple sweet potato (Ipomoea batatas L.) is an important source of anthocyanins, a group of flavonoids with various medicinal benefits. One of the medicinal benefits of anthocyanins is their protection against the detrimental effects of stressors such as uric acid. On the other hand, hyperuricemia and its associated effects are considered significant challenges in human health. Since kidneys are essential organs in uric acid handling and uric acid is associated with kidney disease, this review focuses on re-appraising the role of purple sweet potato anthocyanins as renoprotectors against uric acid-related pathobiology. Future studies regarding the potential of these anthocyanins as renoprotectors are also discussed.

Physical Properties of Tapioca Starch-based Film Indicators with Anthocyanin Extract from Purple Sweet Potato (Ipomea batatas L.) and Response to pH Changes

Intelligent packaging comes in the form of interactive film indicator using a natural pigment compound sensitive to pH changes. The development of intelligent packaging as an indicator film by utilizing natural pigment compounds that are related to pH change and food safety is motivated by increased consumer awareness of food safety. Purple sweet potato (Ipomoea batatas L.) is the source of anthocyanin flavonoid compounds sensitive to pH changes, demonstrated by color changes in film indicators. This research aims to determine physical properties and the pH response of tapioca starch-based film indicators with anthocyanin extract variation from purple sweet potato. Purple sweet potato anthocyanin (PSPA) indicator film was made using tapioca starch as biopolymer by casting method with the addition of anthocyanin extract at concentrations of 0, 5, 10, and 15 g. Furthermore, this research is conducted to analyze the physical properties of the film, and response to pH changes of fresh cow milk, Gindara fish fillet and chicken sausage stored at 7 °C and 25 °C under 48-hour observation. The results showed that the film indicator thickness was 0.72-0.74 mm, tensile strength was 1.23-9.86 MPa, elongation was 14.83-55.74%, and water vapor permeability (WVP) was 1.32-1.78 × 10-14 kg.m/m2.s.Pa. The results of this study indicated that the PSPA indicator films have the potential to be used as smart packaging to monitor food freshness and quality for safe consumption. That was supported by the good physical properties of PSPA indicator films.