A Cassava Starch–Chitosan Edible Coating Enriched with <Emphasis Type="Italic">Lippia sidoides</Emphasis> Cham. Essential Oil and Pomegranate Peel Extract for Preservation of Italian Tomatoes (<Emphasis Type="Italic">Lycopersicon esculentum</Emphasis> Mill.) Stored at Room Temperature

The effect of edible cassava starch–chitosan coatings incorporated with rosemary pepper (Lippia sidoides Cham.) essential oil and pomegranate peel extract on the shelf-life of tomatoes during storage at 25 °C for 12 days was investigated. Sixteen formulations, containing 10 g L^?1 cassava starch and various concentrations of chitosan (5, 10, 20, 30 g L^?1), essential oil (0, 2.5, 5, 10 mL L^?1) and pomegranate peel extract (0, 5, 10, 20 mL L^?1) were prepared and applied to tomatoes. Physical–chemical and microbiological analyses were performed on days 1, 4, 8 and 12. Most of the coatings delayed the ripening of tomatoes, lowering the total soluble solids (38?44 g sucrose kg^?1) and weight loss (93?128 g kg^?1) and maintaining constant firmness compared to the uncoated tomatoes (45 g sucrose kg^?1, 175 g kg^?1) at 12 days of storage. Conversely, except red intensity (a*), which was higher for the uncoated samples, the colour parameters (L*, b*) of the coated and control tomatoes were similar at the end of storage. Uncoated and coated tomatoes showed no contamination during storage. The coatings showed potential to maintain the quality of tomatoes during storage at 25 °C for 12 days. In this context, tomatoes coated with the formulation comprising 10 g L^?1 cassava starch, 10 g L^?1 chitosan, 10 mL L^?1 essential oil and 20 mL L^?1 pomegranate peel extract showed the lowest weight loss and reduced total soluble solids content compared with uncoated ones.     

Effects of Vacuum Packaging and Wrapping with Chitosan-Based Edible Film on the Extension of the Shelf Life of Sea Bass (Dicentrarchus labrax) Fillets in Cold Storage (4 °C)

In the present study, we assessed the possibility of improving the shelf life of fresh sea bass (Dicentrarchus labrax) fillets by using vacuum packaging and wrapping with chitosan-based edible films during cold storage at 4 °C. Sea bass fillet samples were periodically evaluated to assess chemical (pH, trimethylamine and total volatile basic nitrogen) and microbiological (presence of mesophilic aerobic bacteria and psychrotrophic bacteria) quality. Chemical spoilage (trimethylamine and total volatile basic nitrogen) and growth of microorganisms (total mesophilic and total psychrophilic aerobic bacterial counts) were significantly reduced (P?≤?0.05) in vacuum-packaged chitosan film wrapping during cold storage at 4 °C. The results showed that the shelf life of the control and vacuum-packaged groups ended within 5 days, whereas that of vacuum-packaged chitosan film-wrapped samples ended at 25 to 30 days. Therefore, the shelf life of sea bass fillets wrapped in chitosan was prolonged by about 20 days.     

Effect of bilayer coating composed of polyvinyl alcohol,chitosan, and sodium alginate on salted duck eggs

The composite bilayer film based on polyvinyl alcohol, sodium alginate, and chitosan were developed in this study, and the effects of the related coating on internal-quality changes of salted duck eggs (SDEs) during storage were determined. The results showed that the overall properties of the bilayer film were better than those of monolayer films, including storage stability. Coatings could significantly (p < 0.05) reduce quality deterioration of SDEs such as water loss, oil exudation, and gritty. The bilayer coating was more effective in inhibiting the increase of egg yolk pH and total bacterial counts than monolayer coatings. After storage for 60 days, water content of bilayer coated SEDs was 19.7% higher than that of the control SDEs, oil exudation was 38% higher, and gritty texture was 27.9% higher. Moreover, bilayer coating could prolong the shelf life of SDEs to more than 60 days at 25°C and 50% relative humidity according to the results of total bacterial count experiment, while the shelf life of control SDEs was less than 45 days. This study indicated the potential application of bilayer composite coating for preservation of SDEs.     

Improvement of the Quality and the Shelf Life of Figs (<Emphasis Type="Italic">Ficus carica</Emphasis>) Using an Alginate–Chitosan Edible Film

The consumption of fresh figs (Ficus carica) has long been associated with longevity and health benefits. However, fresh figs are highly perishable. An alternative to extend the shelf life of this fruit might be the application of an edible film. Thus, in this study, fig fruits collected at two maturity stages (referred as stages III and IV) were coated with an alginate–chitosan bilayer edible (A–Ch BE) film and the main physiological and quality attributes were evaluated during storage at low temperature (6 °C) at 0, 3, 6, 9, 12, and 15 days of storage. Ethylene and CO₂ productions were considered as physiological parameters, while firmness, color changes, weight loss, and visual infection were the quality attributes evaluated. The application of the film reduced CO₂ production and increased ethylene emission, regardless of the maturity stage of the figs. Firmness for uncoated figs underwent a significant decrease during storage, exhibiting values lower than 1.0 N. On the contrary, for coated figs, firmness was not only maintained but also even increased up to 3 N, for figs of stage III, and up to 2.5 N for the more mature figs (stage IV). Furthermore, coated figs exhibited better external color retention (ΔE < 2), lower weight loss (～8 %), and also lower visual fungal contamination (<5 %) than uncoated fruits during the 15 days of storage at 6 °C, regardless the maturity stage. Therefore, the results indicate that application of an A–Ch BE film not only can improve the overall quality of figs (F. carica var. Mission) stored at 6 °C but is also able to extend their shelf life.     

Combined Effect of Chitosan and Oregano Essential Oil Dip on the Microbiological, Chemical, and Sensory Attributes of Red Porgy (Pagrus pagrus) Stored in Ice

The combined effect of chitosan and oregano essential oil dip on shelf life of whole red porgy (Pagrus pagrus) stored in ice under refrigeration was investigated for a period up to 20 days. Quality attributes monitored during storage included microbiological (total viable counts, Pseudomonas spp., H₂S-producing bacteria including Shewanella putrefaciens, Enterobacteriaceae, and lactic acid bacteria), physicochemical (pH, thiobarbituric acid reactive substances (TBARS), total volatile basic nitrogen (TVB-N), trimethylamine (TMA), and color), and sensory (odor and taste) parameters. Untreated red porgy was used as the control sample. Regarding the chemical indicators of spoilage, TBARS values for all treatments were equal to or less than 0.4 mg MDA?kg^?1 throughout the 20-day storage period. pH values varied between 6.6 (day 0) and 6.9 (day 14) for the various treatments. TVB-N values increased gradually during storage reaching the proposed acceptability limit (30 mg N?100 g^?1) on day 13 for control samples, days 15–16 for samples treated with oregano essential oil, day 20 for samples treated with chitosan, and >20 days for samples treated with chitosan plus oregano essential oil. Likewise, TMA values reached the proposed limit (5–6 mg N?100 g^?1) for red porgy on days 11–12, 14–15, 19–20, and >20, respectively. Finally, sensory evaluation data were in general agreement with microbiological data indicating a product shelf life of ca. 11 days for control samples, 16 days for samples treated with oregano essential oil, 18 days for samples treated with chitosan, and 19–20 days for samples treated with chitosan plus oregano essential oil.     

Effect of anchovy by-product protein coating incorporated with thyme essential oil on the shelf life of anchovy (<Emphasis Type="Italic">Engraulis encrasicolus</Emphasis> L.) fillets

The effects of anchovy by-product protein coatings incorporated with thyme essential oil (TEO) on the shelf life of anchovy (Engraulis encrasicolus L.) fillets stored at 4 ± 1 °C were investigated. We grouped fillets in three categories: untreated fillets, fillets treated in coating solution alone, and fillets treated in coating solution containing 1.5% TEO and analyzed on 0, 3, 6, and 9 days of storage. It was observed that the total volatile basic nitrogen (TVB-N) and pH of all the fillet groups increased under cold storage conditions; however, this increase was much slow in both the coated anchovy fillets. Both coating applications slowed down the lipid oxidation but the coating containing TEO exhibited better effect than coating alone. The coating application alone or with essential oil had limited effect on microbial growth but positively affected the sensory quality. These results revealed that anchovy by-product protein coating mixed with TEO may prolong anchovy fillets’ shelf life stored under cold condition.     

Efficacy of Chitosan-Gallic Acid Coating on Shelf Life Extension of Refrigerated Pacific Mackerel Fillets

The synergistic effect of gallic acid (GA) and chitosan (CS) as edible coatings on the quality and shelf life of Pacific mackerel (Pneumatophorus japonicus) fillets during chilled storage was investigated in this study. Pacific mackerel fillets were periodically evaluated to assess their microbiological (total viable count), physicochemical (pH, total volatile basic nitrogen, biogenic amine, thiobarbituric acid, and K value), and sensory characteristics. The results indicated that CS?+?GA was more effective than either treatment alone in inhibiting microbial growth, protein decomposition, biogenic amine formation, lipid oxidation and nucleotide breakdown, and maintaining better sensory characteristics during storage, thereby extending the shelf life of mackerel by 6 days compared with the control group. Therefore, a coating with the combination of chitosan with GA represents a promising method for maintaining the storage quality of Pacific mackerel fillets and has broad potential applications in the seafood industry as a food-grade biopreservative.     

丁香精油-壳聚糖复合可食性膜对生肉糜保鲜效果的影响

研究丁香精油-壳聚糖复合可食性膜对生肉糜冷藏期间感官品质和货架期的影响。测定生肉糜样品在（4±1）℃冷藏期间细菌总数、pH值、硫代巴比妥酸反应物值、高铁肌红蛋白含量以及感官品质随时间的变化情况。结果表明：添加丁香精油可提高壳聚糖可食性膜的抗菌和抗氧化活性。包裹丁香精油-壳聚糖复合可食性膜可有效抑制生肉糜菌落总数和高铁肌红蛋白含量的增加;同时还可抑制贮藏过程中的脂肪氧化,对感官品质具有良好的保持作用,在（4±1）℃条件下贮藏期可达10～12 d,明显提高了生肉糜贮藏过程中的品质和货架期。丁香精油-壳聚糖复合膜可作为可食性包装膜延长生肉糜冷藏期间的货架期。     

Nanoencapsulation Approach to Improve Antimicrobial and Antioxidant Activity of Thyme Essential Oil in Beef Burgers During Refrigerated Storage

In this study, thyme essential oil (TEO) loaded chitosan nanoparticles (CS-NP-TEO) are prepared by a two-step process including oil/water emulsion and ionic gelation. Five batches of burgers were prepared by following formulation: control (without any TEO), F-0.05-TEO (0.05 % of free TEO), F-0.1-TEO (0.1 % of free TEO), E-0.05-TEO (0.05 % of encapsulated TEO), E-0.1-TEO (0.1 % of encapsulated TEO), and AA-0.05 (0.05 % of ascorbic acid). All samples treated with TEO significantly reduced the population of investigated microbial counts (P?<?0.05) compared to the control during 8 days of storage. At the end of storage, E-0.05-TEO and E-0.1-TEO, presented, respectively, 2.2 and 3 log cycles reduction of Enterobacteriaceae, along with 3.1 and 3.7 log cycles reduction of Staphylococcus aureus. Oxymyoglobin content and redness values reduced with the increase of storage time for all samples. However, AA-0.05 and E-0.1-TEO samples were more efficient at inhibiting discoloration in comparison with E-0.05-TEO and burgers treated with free TEO after 6th day of storage. A significant improvement (P?<?0.05) in the reduction of thiobarbituric acid reactive substances (TBARS) amount was found for all TEO treated burgers in comparison to control samples after 8 days chilled storage. According to the results of sensory analyses, F-0.1-TEO and AA-0.05 samples at 4 days and F-0.05-TEO sample at 8 days of storage were rejected by assessors and considered as an unacceptable case. On the basis of our results, the encapsulation of TEO in chitosan nanoparticles may be a promising technology for the control of undesirable microbial, chemical, and sensorial changes in meat products.     

Coating Satsuma mandarin using grapefruit seed extract–incorporated carnauba wax for its preservation

Grapefruit seed extract (GSE)–incorporated carnauba wax (CW) coating was developed to preserve Satsuma mandarins (Citrus unshiu Marc.). GSE (1.00%, w/w)–incorporated CW (GSE–CW) coating emulsions and GSE (0.50%)–oregano oil (OO, 0.50%)–incorporated CW (GSE–OO–CW) coating emulsions reduced Penicillium italicum disease incidence (%) on mandarin surfaces by 23.6 ± 3.6 and 25.0 ± 5.0%, respectively, relative to that on uncoated mandarin samples (100%). GSE (1.00%)–CW coating emulsions exhibited a higher colloidal stability than GSE (0.50%)–OO (0.50%)–CW coating emulsions. During storage at 25 °C, GSE (1.00%)–CW coating was superior to CW coating in reducing P. italicum disease incidence. CW coating significantly reduced weight loss, respiration rate, and firmness loss during storage at 4 and 25 °C (P < 0.05). The ascorbic acid concentration and peel color were not affected by GSE–CW coating (P > 0.05). These results suggest that GSE–CW coating can extend the post-harvest shelf life of mandarins by inhibiting the growth of P. italicum.     

Characterization and Antifungal Activity of Pomegranate Peel Extract and its Use in Polysaccharide-Based Edible Coatings to Extend the Shelf-Life of Capsicum (<Emphasis Type="Italic">Capsicum annuum</Emphasis> L.)

Effect of pomegranate peel extract (PPE) in two polysaccharide-based edible coatings namely chitosan and alginate on capsicum (Capsicum annuum L.) was studied during storage at 10 °C. The characterization of PPE confirmed the presence of polyphenols such as punicalagin, catechin, and rutin. PPE also demonstrated antifungal activity against the fungal strain of Colletotrichum gloeosporioides. Incorporation of PPE in chitosan coating recorded significant (P?<?0.05) retention of physiological loss in weight, firmness, color, and ascorbic acid in the samples as compared to the control. The restricted losses in total chlorophyll were found to be 22, 29, 38, and 48 in the samples coated with PPE-enriched chitosan, chitosan alone, PPE-enriched alginate, and alginate alone respectively as compared to higher loss of around 71% in control samples during storage. The addition of PPE in these two coatings could also inhibit the microbial growth, maintain sensory scores, and extend the shelf-life up to 25 days at 10 °C.     

Effect of Chitosan Coating Enriched with Ergothioneine on Quality Changes of Japanese Sea Bass (Lateolabrax japonicas)

The effect of chitosan–ergothioneine coating (CHER) on the post-mortem quality and shelf life of Japanese sea bass (Lateolabrax japonicas) stored at 4?±?1 °C for 16 days was investigated. Four different treatments were used: control without coating, CH with chitosan coating, ER with 0.3 % ergothioneine immersion, and CHER with chitosan containing 0.3 % ergothioneine coating. Sea bass pH value, total volatile basic nitrogen, peroxide value, thiobarbituric acid-reactive substances, biogenic amines, color, texture profile, and microbiological and sensory qualities were measured. The results indicate that treatment with CHER coating inhibited increase of total volatile basic nitrogen, peroxide value, and TBA value; maintained tissue hardness; and reduced microorganism counts, such as Pseudomonas, compared with control treatment. The efficiency was better than that of ER or CH treatment. Furthermore, sea bass treated with chitosan–ergothioneine coating also exhibited a positive effect, causing low biogenic amine content, especially putrescine, cadaverine, and histamine. Sensory evaluation proved the efficacy of chitosan–ergothioneine coating by maintaining the overall quality of sea bass during the storage period. Our study suggests that chitosan–ergothioneine coating might be a promising candidate for maintaining sea bass quality and extending their shelf life.     

Improving the quality of minced beef by using mulberry leaves extract

The aim of this research was to study the use of different concentrations (2, 4 and 6% w/w) of methanolic extract of mulberry leaves (Morus spp.) to increase the shelf life of minced beef. Treated samples were compared with the control and gamma irradiated sample at dose level of 5 kGy during cold storage at (4?±?1?°C) for 24 days. Microbiological, chemical and sensory characteristics of treated minced beef were determined every 2 days during the cold storage. Obtained results showed that minced beef treated with different concentrations of mulberry leaves methanolic extract reduced the initial total bacterial count, psychrophilic bacteria, enterobacteriaceae and total mold & yeast as well as prolonged the shelf-life of minced beef compared to the control. Staphylococcus aureus, Bacillus cereus, Enterococcus faecalis and Escherichia coli counts were reduced. The mulberry leaves methanolic extract caused slight increase in the thiobarbituric acid reactive substances and total volatile nitrogen contents of minced beef during the cold storage. Sensory results showed that the shelf life of minced beef was 6 days for the control, and 8, 10, and 14 days for minced samples treated with mulberry leaves methanolic extract (2, 4 and 6%) respectively compared to gamma irradiated (22 days).     

Effectiveness of Zataria multiflora Boiss essential oil and grape seed extract impregnated chitosan film on ready-to-eat mortadella-type sausages during refrigerated storage

BACKGROUND: The effectiveness of chitosan films containing Zataria multiflora Boiss essential oil (ZEO) (5 and 10 g kg^?1) and grape seed extract (GSE) (10 g kg^?1) on lipid oxidation and microbial (lactic acid bacteria, aerobic mesophiles and inoculated Listeria monocytogenes) characteristics of mortadella sausage at 4 °C for 21 days was evaluated. The release of total phenolics (TPs) into sausage was also assessed. RESULTS: All films exhibited antibacterial activity against L. monocytogenes on agar culture media. Chitosan films containing ZEO were the most effective on the growth of bacteria. The growth of L. monocytogenes was significantly inhibited by ZEO‐GSE containing films especially during storage of the sausages for 6 days. Aerobic mesophiles and lactic acid bacteria were the most sensitive and resistant groups to films by 0.1–1.1 and 0.1–0.7 log cycles reduction, respectively. Sausages wrapped by 10 g kg^?1 GSE + 10 g kg^?1 ZEO films had the lowest degrees of lipid oxidation, which was 23% lower than the control. The TPs of ZEO films decreased to zero after 6 days, whereas TPs of GSE films followed a slight decrease during the storage. CONCLUSION: Antimicrobial/antioxidant chitosan film could be developed by incorporating GSE and ZEO for extending the shelf life of mortadella sausage. Copyright © 2011 Society of Chemical Industry     

Edible Antimicrobial Coating Incorporating a Polymeric Iron Chelator and Its Application in the Preservation of Surimi Product

To explore a novel efficient method in food preservation, edible zein coating which incorporates a polymeric chelator was developed and its preservative effect on commercially manufactured fish balls was investigated. The quality indicators of the fish ball during the storage, including sensory quality, total bacterial count, total basic volatile nitrogen (TVB-N) content, thiobarbituric acid reactive substances (TBARS), and pH value were determined. It has been demonstrated that a zein film containing a polymeric chelator significantly (P?<?0.05) improves the sensory properties, retards the growth of spoilage bacteria, and decreases TVB-N and TBARS values. The increase of the microbial load of fish balls coated with antimicrobial zein during a 16-day refrigeration storage period was less than 1 log cfu/g, while the microbial load increased to about 5 log cfu/g for the control group lacking the coating treatment. Although statistically significant differences in the pH values were not observed between coated and uncoated fish balls (P?>?0.05), fish balls coated with antimicrobial zein maintained a relatively stable state during storage. Zein coating which incorporates a polymeric chelator extends fish ball shelf life to 19 days at 4 °C, being more efficient than zein coating lacking a polymeric chelator (13 days). Clearly, polymeric chelator-incorporated zein film could find application in the preservation of surimi products by preventing the growth of bacteria and oxidation of fat during storage.     

Tuna Burgers Preserved by the Selected <Emphasis Type="Italic">Lactobacillus paracasei</Emphasis> IMPC 4.1 Strain

The use of protective microbial strains in combination with modified atmosphere packaging (MAP) and refrigerated storage on the shelf life of tuna burgers was investigated. Preliminary, the protective ability of three lactic acid bacteria (LAB) cultures (Lactobacillus casei, Lactobacillus paracasei, and Lactobacillus plantarum) have been assessed on ready-to-cook tuna burgers. Among them, L. paracasei showed the best preserving performance and significantly controlled both aerobic mesophilic bacteria and Pseudomonas spp. growth. Subsequently, the efficacy of the selected LAB culture under MAP conditions (5% O₂ and 95% CO₂) was assessed evaluating microbial and sensory quality, as well as volatile aldehyde content. Results indicated that the shelf life of burgers containing L. paracasei and packaged under MAP was 4 days longer than the control (shelf life about 6 days) and that the applied procedure represents an effective approach for the mild preservation of fish products.     

Active Banana Flour Nanocomposite Films Incorporated with Garlic Essential Oil as Multifunctional Packaging Material for Food Application

Active plasticized banana flour nanocomposite film (APBNF) incorporated with a different garlic essential oil (GO) content was formed using a solution casting to determine the film properties prior to the investigation of its effectiveness to preserve the roasted peanut quality. The GO concentration was positively correlated with the ultraviolet (UV) light barrier property and antioxidant activity indicating the ability to protect the packed food product from lipid oxidation. Additionally, incorporation of 1 mg/mL GO into APBNF showed the highest antioxidant activity and completely inhibited the growth of Aspergillus flavus. Fourier-transform infrared spectroscopy confirmed the functional group interactions between the film matrix and GO which act as an antioxidant and antimicrobial agent. Thus, APBNF incorporated with 1 mg/mL GO as an active packaging to preserve the quality of roasted peanuts was investigated comparing with a commercial plastic packaging of polyethylene terephthalate/low-density polyethylene (PET/LDPE; PET). The shelf life estimation of roasted peanuts packed in both packaging materials (APBNF and PET) based on the peroxide value (PV) was similar at high storage temperature (45 °C). Therefore, APBNF shows a multifunctional primary food packaging to maintain the quality of roasted peanuts or oily food products.     

Steady- and Unsteady-State Determination of the Water Vapor Permeance (<Emphasis Type="Italic">WVP</Emphasis>) of Polyethylene Film to Estimate the Moisture Gain of Packed Dry Mango

The water vapor permeance (WVP; g m^?2 d^?1 Pa^?1) of packaging films quantifying the water vapor transfer rate between foods and its surroundings is usually determined in units operating under steady-state conditions that do not necessarily reflect food handling scenarios. This study evaluated the determination of the WVP of a polyethylene (PE) film by steady-state method ASTM F1249-06 using a permeability cell and unsteady-state method ASTM E96/E96M in which 102 vacuum-sealed PE bags containing silica gel were stored (37.8 °C, 75% relative humidity) and weighed over 25 days. Average steady-state WVP (2.935 ± 0.365 × 10^?3, n = 4) fell within the 95% quantiles of unsteady-state WVP values (1.818–3.183 × 10^?3, n = 2142). Moisture uptake of dehydrated mango stored at 37.8 °C and 75% relative humidity was predicted with WVP values obtained by both methods. Predictions were validated by monitoring over 25 days the weight gain of 100 PE bags with dry mango. Experimental moisture averages during storage fell within one standard deviation of predictions using the unsteady-state WVP (R ² = 0.974). The same was observed only until day 15 for predictions obtained with the steady-state WVP. Calculations for days 20–25 overestimated the moisture uptake by 6.0–7.2%, resulting in registered R ² = 0.924. The unsteady-state WVP determination is low-cost, uses large numbers of film samples, and allowed more accurate predictions of dry mango moisture uptake. Knowledge of the moisture uptake controlled by the film WVP is essential when predicting the safety and quality changes limiting the shelf-life of foods.     

Effect of Chitosan Gallate Coating on the Quality Maintenance of Refrigerated (4 °C) Silver Pomfret (<Emphasis Type="Italic">Pampus argentus</Emphasis>)

The effect of chitosan (CS)-gallic acid (GA) conjugate (chitosan gallate, CS-g-GA) coating on the quality of silvery pomfret (Pampus argenteus) during refrigerated storage at 4 °C for 15 days was investigated. The total mesophilic and psychrotrophic microbes in control and coated fish samples were counted periodically; physicochemical analyses to determine pH, total volatile basic nitrogen (TVB-N), peroxide value (POV), thiobarbituric acid-reactive substances (TBARS), K-value, and water-holding capacity (WHC) were carried out; and sensory attributes were evaluated. The results indicated that both CS + GA and CS-g-GA coatings effectively preserved the silvery pomfret quality during refrigerated storage. However, CS-g-GA had higher antimicrobial activity and a better ability to inhibit the formation of volatile bases (TVB-N) and lipid oxidation products (POV and TBARS) as well as the degradation of ATP and its breakdown products (K value) than CS + GA during the storage period. Furthermore, the CS-g-GA coating also helped to maintain a higher WHC and had better sensory properties for a longer period of time compared to the other treated samples, thus extending the shelf life and delaying the deterioration of fresh silvery pomfret by 3–6 days during refrigerated storage. These results suggest that a CS-g-GA coating could be employed as an active packaging material in the fish preservation industry.     

Encapsulation of Holy Basil Essential Oil in Gelatin: Effects of Palmitic Acid in Carboxymethyl Cellulose Emulsion Coating on Antioxidant and Antimicrobial Activities

The challenge of using essential oils possessing antioxidant and antimicrobial properties in food industry is to maintain their chemical stability. This research examined the roles of emulsion coating in preventing the degradation of holy basil essential oils (HBEO) during storage. The uncoated HBEO-loaded gelatin microcapsules and those coated with 1, 2, and 3 % palmitic acid emulsified in carboxymethyl cellulose, denoted as UC, C-1P, C-2P, and C-3P, respectively, had HBEO contents of 76.35, 76.09, 68.96, and 59.39 % with the surface oils of 1.31, 0.65, 0.65, and 0.84 %, respectively. The increase in the palmitic acid concentrations caused a significant increase in the L ^* values (p?<?0.05). After 90 days of storage at 30 °C, the surface oils of UC, C-1P, C-2P, and C-3P significantly increased to 3.65, 2.43, 2.15, and 3.03 %, respectively, coincident with the decrease in the L ^* values. X-ray diffraction studies revealed that the crystalline structures of the microcapsules were influenced by gelatin renaturation and palmitic acid polymorphism. The antioxidant activities, expressed as IC₅₀, of the free and encapsulated HBEO before storage were 0.30 mg/ml. After storage, IC₅₀ of only C-2P remained constant, while those of the rest significantly increased (p?<?0.05). The minimum inhibitory concentrations (MICs) and minimum bactericidal concentrations (MBCs) of all the samples against pathogenic bacteria did not change over storage. C-3P exhibited the strongest antimicrobial activity of MIC of 0.625 mg/ml and MBC of 1.25 mg/ml. These findings suggest that the emulsion coating enables shelf life extension of HBEO-loaded gelatin microcapsules.