Application of chitosan for improvement of quality and shelf life of table eggs under tropical room conditions

The shellac and shellac nanocomposite coatings on enhanced the storage stability of fresh eggs for sustainable packaging

Shellac bio-coatings can enhance to improve quality and storage stability of fresh egg qualities with improved shell strength therefore minimizing the reduction the egg losses. Shellac bio-chitosan at 3 concentrations (1 %, 4 % and 8 % w/w) and shellac-1 % montmorillonite nanocomposites were applied as biocoatings to improve storage stability. Shellac-8 % (SH-8 %) coated eggs exhibited the lowest weight loss (1.28 %), significantly. The weight loss of shellac 1 % + MMT and 4 % shellac (SH-4 %) coated eggs was similar each other and had lower weight loss than 1 % shellac (SH-1 %). The Haugh Unit (HU) of eggs with SH-8 % (63.75) had the significantly the highest HU. The SH-4 % (60.24) and SH-1 %/MMT-1 % (58.04) were similar, and the control was the lowest one. The albumin pH of SH-8 % (9.15) coated exhibited a significantly lower than SH-4 % (9.21) and SH-1 %/MMT-1 % (9.24), while the control (9.39) was the highest value at end of storage. For the shellac coated group, total soluble values of albumen reached 12.87 (initial) to 16.331 (SH-1 %), 15.96 (SH-4 %), 15.60 (SH-8 %) and 16.15 (SH-%1-MMT-1 %) at the end of storage. The RWC and foam stability of SH-8 %, SH-4 % and SH-1 % MMT-1 % were similar and higher than 1 % SH and uncoated egg samples. The rheology behaviors were maintained with increasing shellac concentration through the storage. SH-8 % biocoatings were very most effective in filling and sealing the porous in the eggshell and protecting the storage stability and enhancing the strength of the eggshell. Shellac bio-coatings acted as a tiny layer for an effective protective barrier to gas permeability for enhancing the storage stability of the fresh eggs. Higher shellac concentrations (4 and 8 %) and 1 %-MMT were enhanced the storage stability and can be vital solutions for improving shell strength, so it decreases breakage rates.

Egg shelf life can be extended using varied proportions of polyvinyl alcohol/chitosan composite coatings

Using biopolymers in the form of edible coating as egg eco-friendly packaging is a progressive approach. The blending of biopolymers is one of the procedures for overcoming mechanical weakness and benefiting from their maximum synergistic effect. Aiming to determine the relative ratios of chitosan (CH 4 w/v%) and polyvinyl alcohol (PVA 5 w/v%) in the composition of blended coatings, an experiment was conducted with six treatments (r = 3) including different ratios of CH/PVA (0:0; control, 100:0, 75:25, 50:50, 25:75, and 0:100) wt% in a period of 4 weeks of egg storage at ambient temperature, emphasizing eggshell barrier properties. Based on the eggshell analysis result, SEM images and FTIR spectra demonstrated that the components were firmly integrated into the blended coatings as well as had more intertwined than their pure ones, which was also reflected in the evaluation results of their internal quality parameters. In addition, the results showed that by enhancing the ratio of polyvinyl alcohol from 25 to 75 wt%, the blended coating barrier efficiency was relatively improved (p < .05). Meanwhile, the lowest percentage of weight loss (0.57 ± 0.08%), pH value of albumin (8.30 ± 0.04), the highest values of Haugh unit (61.00 ± 0.07), yolk index (0.37 ± 0.02) were observed in eggs coated with CH/PVA 25:75 wt%. But there was no difference in 50 or 70 wt% PVA significantly. Therefore, the CH/PVA blended coatings containing around 50-75 wt% PVA, as egg biodegradable packaging, can be used to extend the shelf life for 2-3 weeks at ambient temperature.

Effect of rosemary (Rosmarinus officinalis) leaf meal supplementation on production performance and egg quality of laying hens

This experiment was conducted to investigate the supplemental effect of rosemary leaf meal (RLM) on egg production and egg quality in Lohmann-Brown laying hens. For each treatment, six replicates were performed with four 24-week-old laying hens for a total of 96 chickens. Dried rosemary leaf meal (RLM) was present in the commercial laying hen ration at 0, 1.7, 3.5 and 5.2%, respectively. The interactions between dietary treatments, egg storage temperatures (4 °C, 21.5 °C), and egg storage durations (7, 14, 21, 28, and 35 days) were examined in factorial designs using a fully randomized design. The data were analyzed using the Statistical Analysis System (SAS, 2014, Ver. 9.3) and Tukey's multiple range tests to separate the means. The inclusion of dried RLM at a level of 5.2% (p < 0.05) significantly improved the hens' daily egg production (78.9%). Feed conversion ratio (2.25) and egg weight (56.7 g) compared to control treatment. Similarly, at 3.5% and 5.2% RLM supplementation, eggshell weight (5.876 g) and eggshell strength increased significantly (p < 0.05) (compared to control, a weight of 3.76 kg/cm2 and a shell thickness (0.37 mm) was observed. In addition, the groups fed 5.2% RLM had significantly higher albumin weight (34.9 g/L), albumin height (6.9 mm), and yolk weight (15.6 g/L). l), yolk height (15.9 mm), yolk color (5.3 points), and Hough unit (83.9 points) than the control groups. Regarding the external characteristics of stored eggs, a group of hens fed at rates of 3.5 and 5.2% RLM showed significantly greater (p < 0.05) egg weight with increases in storage temperature and duration as a control group. There was a significant interaction effect between stored eggs collected from the supplemented groups in terms of egg weight, weight loss, shell weight, shell strength, and shell thickness stored at specific temperatures and storage durations. There was a decrease in albumen level and Haugh unit (HU) with an increase in storage temperature and duration over treatment (P < 0.05). Therefore, better external quality was observed in eggs collected from a group of chickens fed 4.5 and 5.2% RLM after 35 days of storage compared to a control group. Mean albumen height, albumen weight, HU, yolk height, and yolk color of eggs stored in the refrigerator (4 °C) were an exception for yolk weight, which was higher compared to room temperature (21.5 °C). Significantly low (P < 0.05) albumen height (6.61 to 2.96 cm), Hough unit (82.49 to 47.64 points), and yolk height (14.66 to 12.35 mm) were observed at 35 days storage recorded in the control group. In conclusion, supplementation with RLM at 3.5% and 5.2% improved the performance and quality of both fresh and stored eggs.

Egg Freshness Indexes Correlations with Ovomucin Concentration during Storage

The relationship between protein changes and egg quality during storage is a critical area of investigation in both basic science and egg product preservation. Viscosity changes in albumen are a sensitive sign of the deterioration process. Ovomucin, which is present in albumen, plays an important role in the gelation of the albumen. Egg freshness indices and ovomucin concentration will alter in response to storage time. This paper analyzed the correlation and gray relational degree between the Haugh unit (HU), yolk index, albumen pH, and ovomucin concentration. We studied the differences in the ovomucin concentration at different levels of HU, yolk index, and pH during storage. We established an equivalent egg age prediction model using ovomucin concentration as the independent variable. The findings indicated a correlation between the freshness indices and the ovomucin concentration. There was a good, significantly positive relationship between HU and ovomucin concentration (r = 0.713, $P<0.01$ ), a positive correlation between the yolk index and ovomucin concentration (r = 0.699, $P<0.01$ ), and a negative correlation between albumen pH and ovomucin concentration (r =  −0.683, $P<0.01$ ). The highest Pearson correlation coefficient (r = 0.970, $P<0.01$ ) was obtained between the albumen and ovomucin concentration. Significant differences in ovomucin concentration were observed when HU, yolk index, and pH were varied. The gray relational degree between each freshness parameter and ovomucin concentration was greater than 0.8. Between the HU and ovomucin concentration, there was a gray correlation degree of 0.885, indicating that the HU was the primary factor affecting ovomucin concentration variation during storage. During storage, at 22°C, the ovomucin concentration in albumen was significantly and negatively related to storage time (r = −0.926, $P<0.05$ ). The coefficient of determination for the equivalent egg age prediction model with ovomucin concentration as the independent variable was 0.985 ( $P<0.05$ ), indicating strong reliability. The study’s findings show the possibility of nondestructive prediction of an egg’s internal microscopic protein composition using its freshness index value.

Combination of cassava starch biopolymer and essential oils for coating table eggs

This work aimed to evaluate the eggshell microbiota and the internal egg quality after coatings with cassava starch biopolymer enriched with different essential oils during 35 days of storage at 20°C. A total of 369 brown table eggs were used and distributed in the following treatments: uncoated eggs, coated with cassava starch + Ginger essential oil (CS+GIN), cassava starch + Lemongrass essential oil (CS+LEM), and cassava starch + Tahiti lemon essential oil (CS+TAH). The count of total aerobic mesophilic bacteria on coated eggshells at 0 and 35 days of storage were similar to each other (mean 0.70 ± 0.37 and 0.91 ± 0.22 log10 CFU/mL) and significantly lower compared to uncoated eggs (2.21 ± 0.17 and 3.17 ± 0.22 log10 CFU/mL), in that order. On the 35th day, coated eggs showed similar Haugh unit (HU) values between them (mean 70.61 ± 5.35; classified as A - high quality) and significantly higher than uncoated eggs (51.60 ± 4.28; classified as B - average quality). Cassava starch coatings added with essential oils preserved the internal quality of the eggs during storage for 5 weeks at 20°C, reducing the eggshell microbiota and effectively keeping it at low levels during storage.

Preservation of duck eggs through glycerol monolaurate nanoemulsion coating

Duck eggs have a short storage life. In this study, water-washed duck eggs and glycerol monolaurate (GML) coated duck eggs were stored at 25 °C for 70 days (away from light). The water-washed duck eggs started to lose weight from the 4th week. At the same time, Haugh unit and egg yolk index of the water-washed duck eggs started decreasing. The normal GML coating solution (NGML), the higher concentration GML diluent (HGML), and the lower concentration GML diluent (LGML) showed different preservation effects. Among them, NGML showed the strongest protection effect against spoilage of duck eggs. After 70-days storage, the weight loss rate of the NGML coated duck eggs was <6%, which was 4 times lower than that of the water-washed duck eggs; the Haugh unit and the surface morphology were also better than that of the water-washed duck eggs. Furthermore, the total colonies in NGML coated sample was >4 log CFU/g less than that was found in the water-washed samples (Control). The HGML and LGML coating agents were less effective but they might be suitable for the short storage of duck eggs due to the lower cost. Overall, this study provides a sound basis for the preparation and utilization of GML coating solution. The GML coating method is able to extend the shelf life of duck eggs by more than 6 weeks.

Effects of Linseed Meal and Carotenoids from Different Sources on Egg Characteristics, Yolk Fatty Acid and Carotenoid Profile and Lipid Peroxidation

The present study aimed to evaluate the effect of supplementing the diet of laying hens with linseed meal and carotenoids from different sources on egg characteristics, yolk fatty acid and carotenoid profile, and lipid peroxidation. A 4-week experiment was conducted on 168 Lohmann Brown layers (43 weeks of age), assigned to four dietary treatments (42 hens/group; 21 replicate/groups with 2 birds/pen) consisting of a control diet (C) and three diets simultaneously supplemented with 6% linseed meal and 2% dried kapia pepper (E1), 2% dried sea buckthorn pomace (E2) and 2% dried carrot (E3). Every 2 weeks, 18 eggs/group/period were collected randomly from each group and used to determine the egg quality and nutritional parameters. The results showed that dietary linseed meal and carotenoids sources improved egg color, carotenoids’ accumulation in egg yolk and fatty acid profile, especially the n-3 PUFA content. Dietary carotenoids supplementation reduced, n-6/n-3 ratio, cholesterol content of the egg yolk and improved yolk pH, egg thickness and yolk oxidative stability. In conclusion, the use of these sources of carotenoids in the linseed meal enriched diets could be an effective way to improve the nutritional properties of the eggs without affecting their quality and consumer’s safety.

Chitosan and Derivatives: Bioactivities and Application in Foods

Chitosan is a biodegradable, biocompatible, and nontoxic aminopolysaccharide. This review summarizes and discusses the structural modifications, including substitution, grafting copolymerization, cross-linking, and hydrolysis, utilized to improve the physicochemical properties and enhance the bioactivity and functionality of chitosan and related materials. This manuscript also reviews the current progress and potential of chitosan and its derivatives in body-weight management and antihyperlipidemic, antihyperglycemic, antihypertensive, antimicrobial antioxidant, anti-inflammatory, and immunostimulatory activities as well as their ability to interact with gut microbiota. In addition, the potential of chitosan and its derivatives as functional ingredients in food systems, such as film and coating materials, and delivery systems is discussed. This manuscript aims to provide up-to-date information to stimulate future discussion and research to promote the value-added utilization of chitosan in improving the safety, quality, nutritional value and health benefits, and sustainability of our food system while reducing the environmental hazards.

The effect of resin coating on the quality characteristics of chicken eggs during storage

In this study, after washing, changes in the quality characteristics of chicken eggs coated with apricot, almond, and sour cherry tree resins were examined during two different temperatures (4 °C and 22 °C) storage for 60 days. While air cell height, weight loss, albumen and yolk pH and a* (redness) values increased in all samples during storage, Haugh unit, albumen and yolk index, shell fracture and vitelline membrane strength, albumen and yolk L* (lightness) and b* (yellowness) values decreased (P < 0.05). The lowest weight loss (0.54 g) and air cell height (2.89 mm), highest Haugh unit (73.95 HU), albumen index (8.81%), and yolk index (40.37%) were found in the samples coated with sour cherry wood resin stored at 4 °C. The shell breakage and vitelline membrane strength of the coated samples were determined to be higher than the control samples and the samples stored after washing. Higher weight loss, air cell height, and pH values, while lower Haugh unit, Albumen and yolk index were found in samples stored at 22 °C (P < 0.05). At the end of storage, the maximum increase in the counts of total aerobic mesophilic and psychrophilic bacteria was found in the albumin and egg yolk of washed samples stored at ambient temperature. As a result, the coating materials prepared with the resin of apricot, almond, and sour cherry trees were suitable for eggshell's shelf life extension. PRACTICAL APPLICATION: The consumers demand the eggs be in their freshest condition, but the currently available storage conditions are not sufficient to maintain freshness in many regions of Turkey. The physical, chemical and, microbiological qualities of the eggs coated with wood resins were determined to be superior compared to other samples. Because resins have good barrier properties, it is recommended to conduct extensive studies on their applicability in different products.

Conservation of the internal quality of eggs using a biodegradable coating

This study aimed to evaluate the effect of a pectin biofilm on the preservation of refrigerated and unrefrigerated eggs during 5 wk of storage based on egg weight loss, albumen height, Haugh unit (HU), and the yolk index (YI). A total of 1,200 nonfertile eggs from GLK Bankiva laying hens (40 wk of age), which were freshly laid and came from a single collection, were obtained from a model poultry rearing system (Planaltina, Federal District, Brazil) that meets all animal welfare criteria. The experimental outline was entirely randomized, with 20 treatments in a factorial scheme of 2 × 2 × 5, with 2 biofilm treatments (with and without) × 2 storage temperatures (refrigeration: 5°C and ambient: 25°C) × 5 storage periods (7, 14, 21, 28, and 35 d), with 12 repetitions per treatment. Starting from the third storage week, increased weight loss (%) was observed in noncoated eggs (4.46 ± 1.06; 5.61 ± 1.37; 6.93 ± 1.66%) compared with biofilm-coated eggs (3.57 ± 1.26; 4.74 ± 1.8; 6.05 ± 2.21%), respectively. The HU variation in the pectin-coated eggs (86.84–78.02) was smaller than that in the noncoated eggs (83.01–64.36) between the beginning (7 d) and the end (35 d) of the experimental period. Eggs with and without biofilm stored in the refrigerator presented average HU values of 91.26 ± 6.27 and 88.35 ± 6.96, respectively. In contrast, when kept at room temperature, eggs with the coating presented higher HU values (71.27 ± 10.78) than eggs without the coating (59.11 ± 15.97). Coated eggs (0.37 ± 0.16) showed higher YI values than noncoated eggs (0.35 ± 0.16). A pectin-based biofilm effectively maintained egg quality during the 35 d of storage.

Distilled pyroligneous liquor obtained from Eucalyptus grandis and chitosan: physicochemical properties of the solution and films

The pyroligneous liquor is a product obtained during the production of charcoal, with well-known antimicrobial activity. In this work, we characterized the physical chemistry properties of a formulation composed of distilled pyroligneous liquor (DPL), obtained from Eucalyptus grandis, and chitosan. A good interaction between the polymer and the solvent was observed. Auto-supported films were prepared with these systems and characterized with respect to their structure and photo-protection properties, water vapor permeability, and resistance to water and to thermal degradation. They present a semi-crystalline structure and are hygroscopic, but are stable under immersion for up to 7 days. The swelling degree in water is 300% in weight and the permeability to water vapor was between 30 and 45 g m^-1 h^-1 (for films with 80 to 10 μm, respectively). The obtained films are able to efficiently block the incident UVB and UVC radiation; the molar absorptivity decreases exponentially with increasing wavelength and is stable up to 300 °C. These properties confer desirable properties to the films, obtained from these precursors of a renewable source, to be used as coatings.

Application of Transglutaminase Crosslinked Whey Protein–Pectin Coating Improves Egg Quality and Minimizes the Breakage and Porosity of Eggshells

It is well known that an effective way to improve the quality attributes of food is the use of coatings. Moreover, there is evidence of the use of dairy byproducts to design coatings to improve the shelf life of food products. This study was conducted to explore the effectiveness of a film forming solution containing whey protein–pectin complex enzymatically reticulated by transglutaminase (TGase) applied as a coating on eggshells to preserve the internal quality of eggs stored under environmental conditions (25 ± 1 °C and 35% HR) during 15 days storage. Eggs properties tested included yolk index, albumen and yolk pH, albumen CO2 content, water loss, shell strength, and microbial permeability through the shell. The results showed that the coating maintained a higher yolk index and albumen carbon dioxide content, reduced the weight loss and increased both albumen and yolk pH values with respect to the uncoated eggs. All coated eggshells showed greater strength than those of uncoated eggs. Moreover, by using Blue Lake dye penetration method we demonstrated that the coating reduced the Blue Lake dye penetration confirming the effectiveness of the coating on the reduction of post-wash bacterial penetration. These results suggest that the studied coating can be useful to preserve internal egg quality but also to reduce the breakage of eggshell and egg microbial contamination. Based on this result we can conclude that the coating made with whey protein–pectin crosslinked by TGase could be an effective strategy to increase the shelf life of eggs preserved in environmental conditions and to reduce economic losses due to the eggs breakage during their marketing.

Challenges and opportunities related to the use of chitosan as a food preservative

Chitosan has attracted a growing attention as a food preservative due to its versatility, nontoxicity, biodegradability and biocompatibility. This review aims to provide a critical appraisal of the limitations and opportunities of the use of chitosan as a food preservative. The application of chitosan as a food preservative necessitates insights into mechanisms of chitosan-mediated cell death and injury, factors affecting chitosan activity and effects of chitosan on food safety and quality. Chitosan exerts antimicrobial activity by perturbing the negatively charged cell envelope of micro-organisms with its polycationic structure. Intrinsic characteristics, including molecular weight and degree of deacetylation (DD), and other ambient conditions, including pH, temperature and neighbouring components, affect chitosan activity. Because the antimicrobial activity of chitosan is mainly based on ionic interactions with negatively charged components of the bacterial cell envelope, the food matrix can strongly interfere with the antimicrobial activity of chitosan. Despite its limited antimicrobial efficacy, chitosan demonstrates both bactericidal and bacteriostatic effects in specific food products. Moreover, chitosan can also enhance the efficacy of commercial intervention technologies, such as heat and pressure treatment, and aid the preservation of food quality, including retardation of lipid oxidation, weight loss and deterioration in sensory attributes.

Effects of Chitosan Coating Structure and Changes during Storage on Their Egg Preservation Performance

To explore the influences of chitosan coating structure and structure changes during storage on egg preservation, eggs coated by chitosan solution for single time (CS1), two times (CS2), and three times (CS3) were prepared separately and stored with untreated eggs (CK1), eggs washed by water (CK2) and eggs treated by acetic acid solution (CK3) at 25 °C, 80% RH. The weight loss, Haugh unit, yolk index, albumen pH, eggshell morphologies and infrared (FTIR—Fourier Transform Infrared) spectra of all the samples were monitored. CS2 and CS3 presented the lowest weight loss, highest Haugh unit and yolk index, stabilized pH, and the highest thickness of chitosan coating layers (>2 μm) among all the groups, which extended egg shelf life for 20 days longer compared to CK1 and CK2. CS1 with very thin chitosan coating showed similar egg qualities with CK3, which are second only to CS2 and CS3. Furthermore, destructions were found on chitosan coatings during storage as revealed by the eggshell morphologies and FTIR spectra, which caused the quality deterioration of eggs. The results demonstrated that eggs with the thickest coating showed the best qualities during storage, while destructions on coating layers led to the quality drop of eggs.