Effect of chitosan coatings enriched with cinnamon oil on the quality of refrigerated rainbow trout

Use of chitosan coating in increasing the shelf life of liquid smoked Nile tilapia (Oreochromis niloticus) fillet

The aim of this research was to evaluate the efficiency of liquid smoking and chitosan coating on the shelf life of Nile tilapia (Oreochromis niloticus) fillets. Fillets without liquid smoked and chitosan coating (control), liquid smoked fillets (LS), and liquid smoked and chitosan coated fillets (LSCh) were stored at 4 ± 1 °C for 30 days. The physicochemical (pH, moisture content, water activity-aw, color, texture, total volatile bases nitrogen-TVB-N and thiobarbituric acid reactive substances-TBARS) and microbiological analyses (mesophilic and psychrotrophic counts) and the electrophoresis profile of samples were carried out. Physicochemical parameters, such as TVB-N and TBARS, were reduced in the tilapia fillets with liquid smoking. The presence of the coating of chitosan was effective for the control of the microorganisms during storage. This work showed that the addition of a chitosan coating in liquid-smoked fillets further enhanced the effect of preservation.

Application of fungal chitosan incorporated with pomegranate peel extract as edible coating for microbiological, chemical and sensorial quality enhancement of Nile tilapia fillets

Fish are generous sources for providing man with his essential nutritional requirements, but the extreme susceptibility to quality deterioration hinders their optimal usage and storage. Natural derivatives are always the perfect alternatives for food preservation. The application of fungal chitosan (Ch), from Aspergillus niger, and pomegranate peel extract (PPE), in coating films for Nile tilapia (Oreochromis niloticus) fillets preservation ‎and maintaining their microbiological, chemical and sensorial quality during cooled storage at 4°C for 30days, was investigated.‎ Fish fillet were coated with Ch (2%) and combined Ch+PPE, at PPE percentages of 0.5, 1.0, 1.5 and 2.0%. Fillets coating resulted in sharp decrease of the entire microbial counts during storage; the increased concentrations from PPE strengthened coating film antimicrobial activity. Additionally, fillets coating could retard the chemical spoilage parameters increasing, i.e. nitrogen volatile base (TVB-N), peroxide value (PV) and reactive substances of thiobarbituric acid (TBARS), during storage period. The sensory evaluation indicated higher preferences for the odor, texture, color and overall quality of coated samples. Fish fillets coating with Ch and Ch+PPE could be recommended for shelf life extension and maintaining the microbiological, chemical and sensorial quality through the application of safe preservatives from natural origins.

Biogenic Amines and Predictive Models of Quality of Rainbow Trout ( Oncorhynchus mykiss ) Fillets during Storage

To estimate biogenic amines and changes in quality of rainbow trout ( Oncorhynchus mykiss ) fillets at different temperatures, we determined the sensory attributes, total volatile basic nitrogen (TVB-N), total viable counts (TVC), and biogenic amines (BAs) of samples that were untreated (CK) or dry cured with 1.8% salt (T). There was no significant difference between CK and T samples in terms of TVB-N, TVC, and BAs. TVB-N and TVC increased significantly (P < 0.05) with storage time at 3, 9, and 15°C. Putrescine (PUT) and cadaverine (CAD) increased significantly (P < 0.05) at -3, 3, 9, and 15°C during storage. Histamine formed more easily when storage temperatures were higher. The kinetic models of sensory scores for TVB-N, TVC, PUT, CAD, and the sum of PUT and CAD (PUT+CAD) in T samples versus storage time and temperature were developed based on the Arrhenius equation. High regression coefficients (R² > 0.9) indicated the acceptability of the kinetic model for predicting changes in the quality of the rainbow trout fillets. Relative errors between predicted and experimental values of TVB-N, TVC, and PUT+CAD were all within 10% except for TVB-N on day 6. The prediction model based on TVB-N, TVC, and PUT+CAD can be applied to evaluate changes in quality of rainbow trout fillets from -3 to 15°C (270 to 288 K).

Effect of Film-Forming Alginate/Chitosan Polyelectrolyte Complex on the Storage Quality of Pork

Meat is one of the most challenging food products in the context of maintaining quality and safety. The aim of this work was to improve the quality of raw/cooked meat by coating it with sodium alginate (A), chitosan (C), and sodium alginate-chitosan polyelectrolyte complex (PEC) hydrosols. Antioxidant properties of A, C, and PEC hydrosols were determined. Subsequently, total antioxidant capacity (TAC), sensory quality of raw/cooked pork coated with experimental hydrosols, and antimicrobial efficiency of those hydrosols on the surface microbiota were analysed. Application analyses of hydrosol were performed during 0, 7, and 14 days of refrigerated storage in MAP (modified atmosphere packaging). Ferric reducing antioxidant power (FRAP) and (2,2-diphenyll-picrylhydrazyl (DPPH) analysis confirmed the antioxidant properties of A, C, and PEC. Sample C (1.0%) was characterized by the highest DPPH value (174.67 μM Trolox/mL) of all variants. PEC samples consisted of A 0.3%/C 1.0% and A 0.6%/C 1.0% were characterized by the greatest FRAP value (~7.21 μM Fe2+/mL) of all variants. TAC losses caused by thermal treatment of meat were reduced by 45% by coating meat with experimental hydrosols. Application of PEC on the meat surface resulted in reducing the total number of micro-organisms, psychrotrophs, and lactic acid bacteria by about 61%, and yeast and molds by about 45% compared to control after a two-week storage.

A Chitosan Coating Containing Essential Oil from Origanum vulgare L. to Control Postharvest Mold Infections and Keep the Quality of Cherry Tomato Fruit

The efficacy of an edible chitosan coating (CHI; 4 mg/mL) and Origanum vulgare L. essential oil (OVEO; 1.25 μL/mL) for maintaining the quality of cherry tomato fruit during storage at room (25°C; 12 days) and cold (12°C; 24 days) temperatures was assessed. CHI and OVEO in combination showed in vitro fungicidal effects against R. stolonifer and Aspergillus niger. CHI-OVEO coating reduced the incidence of black mold and soft rot caused by these fungi in artificially contaminated cherry tomato fruit during storage at both temperatures. CHI-OVEO coating delayed the appearance of the first visible signs of black mold and soft rot in artificially contaminated cherry tomato fruit stored at room temperature by 6 days and by more than 9 days in those stored at cold temperature. At the end of storage at room and cold temperature fruit coated with CHI-OVEO showed higher firmness (>2 N/mm) and lower weight loss (>2%) compared to uncoated tomato fruit. CHI-OVEO coating delayed the decrease of lycopene, ascorbic citric acid, glucose and fructose during the storage time assessed at room or cold temperatures. The increase of catechin, myricetin, caffeic and syringic acids was higher (1-9 mg/g) in cherry tomato fruit coated with CHI-OVEO compared to uncoated fruit during the storage at both temperatures studied. CHI-OVEO coating is a feasible treatment for maintaining the storage quality of cherry tomato fruit.

Chitosan films and coatings containing essential oils: The antioxidant and antimicrobial activity, and application in food systems

Chitosan edible films and coatings have shown great promise for their application in food preservation and also are promising systems to be used as essential oil (EO) carriers. This review reports the most recent and relevant studies concerning chitosan films and coatings containing EOs. The effect of EO incorporation on the antioxidant, antibacterial and antifungal activities of chitosan films and coatings in vitro and in vivo, as well as their applications in food systems have been discussed. In general, incorporation of EOs significantly increased the antioxidant, antibacterial and antifungal efficacy of chitosan films and coatings in vitro. EO-incorporated films and coatings also showed greater effectiveness against postharvest fungi and foodborne bacteria in food systems than pure films and coatings. The application of chitosan films and coatings containing EOs usually led to an extension of the shelf-life and reduction of lipid peroxidation of fish and meat products over pure chitosan films and coatings. In addition, chitosan coatings incorporated with EOs were more effective in maintaining fruit and vegetable quality, and controlling their postharvest decay during storage and shelf life than pure chitosan coatings.

Activity of R(+) limonene on the maximum growth rate of fish spoilage organisms and related effects on shelf-life prolongation of fresh gilthead sea bream fillets

R(+)limonene (LMN) is the major aromatic compound in essential oils obtained from oranges, grapefruits, and lemons. The improvement of preservation techniques to reduce the growth and activity of spoilage microorganisms in foods is crucial to increase their shelf life and to reduce the losses due to spoilage. The aim of this work is to evaluate the effect of LMN on the shelf life of fish fillets. Its effectiveness was preliminarily investigated in vitro against 60 strains of Specific Spoilage Organisms (SSOs) and then on gilt-head sea bream fillets stored at 2±0.5°C for 15days under vacuum. LMN showed a good inhibitory effect against tested SSOs strains. On gilt-head sea bream fillets, LMN inhibited the growth SSOs effectively, and its use resulted in a shelf-life extension of ca. 6-9days of treated fillets, compared to the control samples. The LMN addition in Sparus aurata fillets giving a distinctive smell and like-lemon taste to fish fillets that resulted pleasant to panellists. Its use contributed to a considerable reduction of fish spoilage given that the fillets treated with LMN were still sensory acceptable after 15days of storage. LMN may be used as an effective antimicrobial system to reduce the microbial growth and to improve the shelf life of fresh gilt-head sea bream fillets.

Shelf life extension of green chillies (Capsicum annuum L.) using shellac-based surface coating in combination with modified atmosphere packaging

Shellac-based surface coating was used in combination with passive modified atmosphere (MA) packaging for shelf life extension of fresh green chillies. The green chillies were coated with shellac coating, packed in anti-fog film and kept at 8 ± 1 °C for storage along with uncoated control. The coated and MA packed chillies showed significantly lower respiration rates as compared to control. The physico-chemical characteristics showed significantly lesser variations in terms of physiological loss in weight, firmness, colour, pigments, ascorbic acid and antioxidant activity during storage. A shelf life extension of 48 days was observed for coated and MA packed chillies against uncoated and MA packed (28 days) and control (15 days) ones. Shellac coated chillies showed a shelf life of 30 days at 8 ± 1 °C. Shellac coating along with the passive MA packaging resulted in restriction of metabolic activities (respiration) and delayed senescence and was found most effective in maintaining the postharvest quality of green chillies during low temperature storage.

The impact of stunning methods on stress conditions and quality of silver carp (Hypophthalmichthys molitrix) fillets stored at 4°C during 72h postmortem

This study aimed to evaluate different stunning methods [percussion (T1), immersion in ice/water slurry (T2), and gill cut (T3)] on quality and stress conditions of silver carp (Hypophthalmichthys molitrix) fillets stored at 4°C in 72h postmortem. Rigor index (RI%), behavioral analysis, levels of lactic acid and muscle glycogen were measured for stress level evaluation. Meanwhile, sensory assessment, texture properties, cooking loss, adenosine triphosphate (ATP) related compounds, adenosine monophosphate deaminase (ADA) activity, and acid phosphatase (ACP) activity were analyzed. The least stress condition, significantly (P<0.05) higher initial glycogen content was observed in T1. Ice/water stunning reduced the rate of ATP degradation, reflected in the lowest K value during 72h. Aversive behaviors, significantly (P<0.05) higher cooking loss, hypoxanthine riboside (HxR) content, and lower sensory score were observed in T3. The results indicated that gill cut in aquatic processing industry should be avoided for inferior quality and aversive reactions during stunning.

Preservation Mechanism of Chitosan-Based Coating with Cinnamon Oil for Fruits Storage Based on Sensor Data

The chitosan-based coating with antimicrobial agent has been developed recently to control the decay of fruits. However, its fresh keeping and antimicrobial mechanism is still not very clear. The preservation mechanism of chitosan coating with cinnamon oil for fruits storage is investigated in this paper. Results in the atomic force microscopy sensor images show that many micropores exist in the chitosan coating film. The roughness of coating film is affected by the concentration of chitosan. The antifungal activity of cinnamon oil should be mainly due to its main consistent trans-cinnamaldehyde, which is proportional to the trans-cinnamaldehyde concentration and improves with increasing the attachment time of oil. The exosmosis ratios of Penicillium citrinum and Aspergillus flavus could be enhanced by increasing the concentration of cinnamon oil. Morphological observation indicates that, compared to the normal cell, the wizened mycelium of A. flavus is observed around the inhibition zone, and the growth of spores is also inhibited. Moreover, the analysis of gas sensors indicate that the chitosan-oil coating could decrease the level of O₂ and increase the level of CO₂ in the package of cherry fruits, which also control the fruit decay. These results indicate that its preservation mechanism might be partly due to the micropores structure of coating film as a barrier for gas and a carrier for oil, and partly due to the activity of cinnamon oil on the cell disruption.

Effects of glycinin basic polypeptide on sensory and physicochemical properties of chilled pork

Effects of glycinin basic polypeptide (GBP) on sensory and physicochemical properties of pork during chilled storage were investigated. Pork treated with GBP was analyzed periodically for sensory properties, pH, total volatile base nitrogen (TVB-N), α-thiobarbituric acid (TBA), and total viable count (TVC) values. Compared with controls, TBA values of pork treated with GBP did not change. TVB-N, pH, and TVC values of pork showed reductions with increasing concentrations of GBP during 8 days of storage. However, there were increases in sensory scores. TVC values of treated pork showed a positive linear relationship with both pH and TVB-N values. GBP at 0.16 and 0.20% efficiently inhibited bacterial growth, and enhanced chilled pork sensory scores. Therefore, GBP has potential as a pork biological preservative for extension of shelf life during chilled storage.

Biodegradable Chitosan Coating Incorporated with Black Pepper Essential Oil for Shelf Life Extension of Common Carp (Cyprinus carpio) during Refrigerated Storage

Chitosan (Ch) coating incorporated with black pepper essential oil (Ch+BPEO) was studied to extend the shelf life of common carp (Cyprinus carpio) during refrigerated storage at 4 ± 1°C. The chemical composition of BPEO was characterized using gas chromatography-mass spectrometry (GC-MS). Antibacterial properties of BPEO were determined by disk diffusion agar, MIC, and MBC. Ch (2% [wt/vol]) and Ch+BPEO (2% [wt/vol] Ch with 1.5% [vol/vol] BPEO) were used for common carp fillet coating. The samples were analyzed periodically for chemical (pH, total volatile basic nitrogen) and microbiological (aerobic plate count, psychrophilic bacteria count, lactic acid bacteria, and Enterobacteriaceae bacterial counts) characteristics during 16 days. The GC-MS results indicated that main components in BPEO were carene, caryophyllene, limonene, β-pinene, and α-pinene. The samples coated with Ch and Ch+BPEO resulted in lower pH and total volatile basic nitrogen values in comparison with the control. The microbiological analysis of fish fillets during refrigerated storage clearly indicated that Ch+BPEO coating significantly reduced the fish fillet microbial load. The aerobic plate count, psychrophilic bacteria count, lactic acid bacteria count, and Enterobacteriaceae bacterial count of samples coated with Ch+BPEO were reduced approximately 4.1, 3.9, 2.3, and 2.8 log CFU/g, respectively, at the end of the storage period. Finally, Ch and Ch+BPEO effectively improved the quality of fish fillet during refrigerated storage and extended the shelf life of fish fillets from 8 to 16 days.

KEY WORDS

Black pepper; Chitosan; Common carp; Essential oil.

Effect of Encapsulated Bitter Orange Peel Extract and BHT on the Quality of Common Carp Fillet during Refrigerated Storage

The aim of the present study was to evaluate antioxidative activities of the encapsulated and unencapsulated bitter orange peel extract on the shelf-life of the common carp fillets during 16 days of refrigerated storage. Common carp fillets were treated with bitter orange peel extract (0.5 and 1% w/w), liposomal encapsulated bitter orange peel extract (0.5 and 1% w/w) and beta-hydroxytoluene (BHT, 100 and 200 ppm); their quality changes in terms of total volatile basic nitrogen (TVB-N), free fatty acid (FFA) peroxide value (PV), thiobarbituric acid (TBA) and sensory characteristics were investigated. Results showed that the encapsulated and pure extract and BHT could reduce chemical deterioration and lipid oxidation in the fillets compared to the control, as reflected with lower TVBN, FFA, PV and TBA values. Furthermore, common carp fillets treated with high concentration (1%) of the encapsulated bitter orange peel extract showed the lowest amount of lipid oxidation during the storage period compared with the others without any undesirable changes in sensorial attributes.