A novel emulsion coating and its effects on internal quality and shelf life of eggs during room temperature storage

Effects of mineral oil (MO), chitosan solution (CH) and their emulsions (MO:CH = 75:25, 50:50, and 25:75 ratios) as coating materials in preserving internal quality of eggs were evaluated during a 5‐weeks storage at 25 °C. Consumers (n = 109) evaluated surface properties and purchase intent of freshly coated eggs. As storage time increased, Haugh unit and yolk index values decreased whereas weight loss increased. Noncoated eggs rapidly changed from AA to B and C grades after 1 and 3 weeks, respectively. However, all emulsion‐coated eggs maintained their A‐grade quality for 4 weeks. Compared with noncoated eggs, all emulsion coatings reduced weight loss of eggs by at least seven times (0.88–1.03% vs. 7.14%). Only MO:CH = 25:75 emulsion‐coated eggs were not sensorially glossier than noncoated eggs. All emulsion‐coated eggs had >80% positive purchase intent and were negative for Salmonella. This study demonstrated that MO:CH emulsion coatings preserved internal quality and prolonged shelf life of eggs.     

Internal quality and shelf life of eggs coated with oils from different sources

Selected internal quality and shelf life of eggs coated with oils from differences sources (mineral oil, canola oil, corn oil, grape seed oil, olive oil, soybean oil, and sunflower oil) were evaluated during 5 wk of storage at 25 °C. As the storage time increased, weight loss increased whereas Haugh unit and yolk index values decreased. Throughout the 5 wk of storage, eggs coated with oils, regardless of oil sources, possessed better albumen and yolk quality than the control noncoated eggs. Oil coating minimized weight loss of eggs (<0.8%) compared with that (7.26%) of the noncoated eggs after 5 wk of storage at 25 °C. No significant differences in internal quality (weight loss, Haugh unit, yolk index, and albumen pH) were generally observed among oil-coated eggs during 5 wk of storage. Based on the Haugh unit, the grade of noncoated eggs changed from AA at 0 wk to A at 1 wk and to B after 3 wk whereas that of oil-coated eggs from AA at 0 wk to A at 4 wk and maintained A grade until 5 wk. This study demonstrated that oil coating, irrespective of oil sources, preserved the internal quality, minimized weight loss (<0.8%), and extended the shelf life of eggs by at least 3 wk longer than observed for the noncoated eggs at 25 °C storage. Soybean oil was a more practical option as a coating material for eggs due to its low cost. PRACTICAL APPLICATION: Eggs are highly perishable and susceptible to internal quality deterioration when stored above 7 °C. Refrigeration of eggs may be seldom practiced in some developing regions of the world. Therefore, an alternative method, that is inexpensive yet effective, to preserve the internal quality of eggs and to prevent microbial contamination is needed. Oil coating has been proven to preserve the internal quality, prolong shelf life, and minimize weight loss of eggs. This study demonstrated that, compared with other vegetable oils, soybean oil was a more practical option as a coating material for eggs during 5 wk of storage at 25 °C due to its low cost.     

Chitosan-soybean oil emulsion coating affects physico-functional and sensory quality of eggs during storage

Effects of soybean oil (SO) and chitosan-soybean oil (CH:SO = 40:60) emulsion as coating materials for preserving internal quality of eggs were evaluated during 7 and 15 weeks storage at 25 °C and 4 °C, respectively. Consumers (n = 150) assessed surface properties and purchase intent of freshly coated eggs. Noncoated eggs deteriorated from AA to B grade after 1 week while coated eggs retained A grade up to 5 weeks at 25 °C. Amongst coatings, CH:SO emulsion maintained a lower albumen pH while SO was better at reducing weight loss. Effect of refrigeration on albumen pH was minimal. Weight loss of coated eggs was <3% after 7 weeks at 25 °C. Emulsion capacity and emulsion viscosity were minimally affected by coating and refrigeration, and their trends were more correlated to the yolk index at 25 °C than at 4 °C. Only SO-coated eggs were not sensorially smoother than noncoated eggs; however, CH:SO emulsion-coated eggs had the least shell colour changes (ΔE^∗, values at day 0 as a reference) during storage at 25 °C. All coated eggs had 85% positive purchase intent. SO and CH:SO emulsion coatings significantly extended egg shelf-life compared to that of noncoated eggs at room and refrigerated storage.     

Effects of initial albumen quality and mineral oil–chitosan emulsion coating on internal quality and shelf‐life of eggs during room temperature storage

Effects of mineral oil (MO) and mineral oil–chitosan emulsion (MO:CH = 25:75) as coatings on internal quality and shelf‐life of eggs were evaluated during 5‐week storage at 25 °C. Eggs with three different initial albumen qualities [Haugh unit (HU): H = 87.8, M = 75.6 and L = 70.9] were evaluated. As storage time increased, HU and yolk index values decreased whereas weight loss increased. Coating with MO and/or 25:75 MO:CH emulsion could preserve the internal quality for at least 4 more weeks for H‐eggs and at least 3 more weeks for M and/or L‐eggs, all with weight losses <0.92%. All coated eggs had >70% positive purchase intent, and their colour differences at week 0 could not be detected by naked human eye (ΔE^* < 3.0, noncoated eggs as reference). Consumers significantly differentiated freshly MO‐coated from noncoated eggs on overall surface appearance. This study demonstrated that MO and 25:75 MO:CH emulsion coatings could preserve internal quality and prolong shelf‐life of eggs.     

Edible coating affects physico‐functional properties and shelf life of chicken eggs during refrigerated and room temperature storage

Effects of chitosan, whey protein concentrate (WPC), mineral oil (MO) and/or soybean oil (SO) coating on egg quality were compared at 25 and 4 °C, respectively, during 5 and 20 weeks of storage. Storage time and temperature, and type of coating significantly affected Haugh unit, yolk index, weight loss, albumen pH and emulsifying capacity. Shelf life was extended 4 weeks by MO and SO and 2 weeks by chitosan and WPC longer than that observed for noncoated eggs at 25 °C. MO‐ and SO‐coated eggs maintained AA grade for 20 weeks at 4 °C. Weight loss of SO‐coated eggs was <1% after 5 weeks at 25 °C and after 20 weeks at 4 °C. Yolk index and emulsifying capacity were more correlated at 25 °C than at 4 °C. MO and SO were more effective coating materials, with SO providing a more cost‐effective coating for extending egg shelf life.     

Selected Quality and Shelf Life of Eggs Coated with Mineral Oil with Different Viscosities

ABSTRACT:  Selected quality and shelf life of eggs coated with mineral oil having 6 different viscosities (7, 11, 14, 18, 22, and 26 cP) were evaluated during 5 wk of storage at 25 °C. As the storage time increased, weight loss and albumen pH increased whereas Haugh unit and yolk index values decreased. After 5 wk of storage, eggs coated with 11, 14, 18, 22, or 26 cP oil possessed better quality than the control noncoated eggs and eggs coated with 7 cP oil. Oil coating, irrespective of viscosities, did not improve the emulsion capacity. There was an observable trend that coating with 26 cP oil was more effective in preventing weight loss and in maintaining the Haugh unit of eggs compared with coating with other viscosities of mineral oil. Based on the Haugh unit, the grade of noncoated eggs changed from "AA" at 0 wk to "C" after 3 wk whereas that of 26 cP oil-coated eggs from "AA" at 0 wk to "A" at 3 wk and "B" at 5 wk of storage. Coating with 26 cP oil reduced the weight loss of eggs by more than 10 times (0.85% compared with 8.78%) and extended the shelf life of eggs by at least 3 more weeks compared with the noncoated eggs.     

Effectiveness of chitosan‐based coating in improving shelf‐life of eggs

Despite eggs having a natural packaging—shell—they are perishable and can lose their quality during storage. Chitosan‐based coatings were applied to shell eggs to examine potential effects on egg quality properties (weight loss, Haugh unit, yolk index) during 4 weeks of storage. Mineral amounts in yolks were also evaluated after 4 weeks of storage. Three chitosan‐based coatings produced with organic acids (acetic‐(C‐AA), lactic‐(C‐LA), and propionic (C‐PA)) were evaluated on shelf‐life enhancements of fresh egg quality. All chitosan‐coated eggs showed greater interior quality than the non‐coated eggs. The coatings significantly maintained weight loss compared to the control specimen (4.96%). Lower weight loss (3.45% for C‐PA, 3.53% for C‐LA) was observed in the coated eggs. Eggshell chitosan coat containing lactic and propionic acids maintained higher Haugh unit and yolk index than eggs coated with acetic acid. Uncoated (UC) eggs changed from grade ‘A’ to ‘B’ after 1 week of storage. Chitosan‐based coating containing lactic and propionic acids maintained eggs in grade ‘A’ for 4 weeks. Haugh unit showed that C‐LA and C‐PA effectively maintained eggs at grade ‘A’ quality for at least 3 weeks more than control and 1 week more than C‐AA. Results also indicated that the chitosan coating maintained mineral amounts at nutritional values (especially calcium, iron and magnesium concentration) in yolks after 4 weeks storage. Copyright © 2006 Society of Chemical Industry     

Effects of chitosan coating and storage position on quality and shelf life of eggs

Effects of chitosan coating and storage positions (small-end down, small-end up or horizontal) on internal quality and shelf life of eggs were evaluated during 5 weeks of storage at 25 °C. Compared with noncoated eggs, all chitosan-coated eggs, irrespective of storage positions, had significantly lesser weight loss, higher Haugh units and higher yolk index throughout the storage. Chitosan coating, irrespective of storage positions, extended the egg shelf life by at least 3 weeks at 25 °C compared with noncoated eggs. Noncoated and chitosan-coated eggs placed small-end down tentatively showed better quality than eggs placed small-end up after 3 and 4 weeks of storage. After 5 weeks of storage, storage positions did not significantly affect quality of noncoated and chitosan-coated eggs. There were no notable differences in total amino acid content of the albumen and fatty acid composition of the yolk between noncoated and chitosan-coated eggs after 5 weeks of storage.     

Whey protein isolate coating and concentration effects on egg shelf life

The influences of three different concentrations (6, 12 and 18%) of whey protein isolate (WPI) coatings on shelf‐life enhancements of the fresh egg quality (weight loss, pH, Haugh unit, yolk index and colors) and the shelf life were evaluated at room temperature. All coated eggs showed lower weight loss than uncoated eggs. Less weight loss (2.46 for 12% WPI and 2.38 for 18% WPI) was observed in WPI‐coated eggs. Haugh units (HU) indicated that coated eggs remained in grade ‘A’ during 3 weeks storage period, whereas uncoated (UC) changed from grade ‘A’ to ‘B’ after 1 week of storage. The HU and yolk‐index (YI) values of all WPI‐coated eggs were significantly higher than those of UC. Among the coated eggs, there were no significant differences in HU, but 12 and 18% WPI coated had higher YI than WPI 6% coated and UC. The albumen pH of the UC eggs was significantly higher than that of coated eggs. Yolk lightness (L*) and (b*); shell (a*) and (b*) of coated eggs were not different from UC after 4 weeks. Performance of WPI coatings depended on the concentration up to 12% but not between 12 and 18%. Results also indicated that WPI coatings served as protective barrier for shelf life of the eggs. Copyright © 2005 Society of Chemical Industry     

Comparison of Shelf Life of Eggs Coated with Chitosans Prepared under Various Deproteinization and Demineralization Times

Internal quality of eggs coated with chitosans prepared under various deproteinization (DP at 0, 5, 15 min) and demineralization (DM at 0, 10, 20, 30 min) times was evaluated. Chitosans prepared under DP 0 min/DM 30 min, DP 5 min/DM 30 min, and/or DP 15 min/DM 20 min conditions can be effectively used as an egg‐coating material in preserving the internal quality of eggs compared with chitosan prepared under the DP 15 min/DM 30 min condition. The Haugh unit and yolk index values suggested that the chitosan‐coated eggs can be preserved for at least 2 wk longer than the control noncoated eggs during 5 wk of storage at 25°C.     

The effect of edible eggshell coatings on egg quality and consumer perception

Effects of the various coatings (whey protein isolate, chitosan and shellac) on fresh eggs quality were evaluated based on the interior quality and sensory evaluation during 4 weeks of storage. During storage, all egg weights and albumen heights decreased and albumen pH increased. The lowest weight loss (0.75%) was observed in shellac‐coated eggs. Eggs coated with chitosan and whey protein also had significantly lower weight loss than uncoated (UC) eggs (p < 0.05). The albumen pH of the UC eggs was significantly higher than that of coated eggs and increased during storage time. The Haugh unit and yolk‐index values of all coated eggs were significantly higher than those of UC. Among the coated eggs, the shellac eggs had the highest value of Haugh unit and yolk index. Chitosan and shellac effectively maintained grade ‘A’ eggs for at least 2 weeks more than control and 1 week more than whey protein isolate. On the basis of sensory evaluation, shellac has highest glossiness, but lowest general acceptability. Eggs coated with whey protein had significantly higher general acceptability. Yolk lightness (L*)(a*) and (b*) of coated eggs were not different from UC after 4 weeks. The values of color differences were similar to controls. The study demonstrated that various coatings improved the shelf life of eggs. Copyright © 2005 Society of Chemical Industry     

Chitosan Coating Improves Shelf Life of Eggs

ABSTRACT: Internal and sensory quality of eggs coated with chitosan was evaluated during a 5-wk storage at 25 °C. Three chitosans with high (HMw, 1100 KDa), medium (MMw, 746 KDa), and low (LMw, 470 KDa) molecular weight were used to prepare coating solutions. Coating with LMw chitosan was more effective in preventing weight loss than with MMw and HMw chitosans. The Haugh unit and yolk index values indicated that the albumen and yolk quality of coated eggs can be preserved up to 5 wk at 25 °C, which is at least 3 wk longer than observed for the control noncoated eggs. Based on external quality, consumers could not differentiate the coated eggs from the control noncoated eggs. Overall acceptability of all coated eggs was not different from the control and commercial eggs.     

Effect of various refrigeration temperatures on quality of shell eggs

BACKGROUND: The objective of this study was to evaluate the effects of low storage temperatures on shell egg quality. RESULTS: Approximately 2100 shell eggs were collected and stored at ? 1.1, 0.6, 2.2, 3.9, 5.6 and 7.2 °C for up to 4 weeks. Eighteen eggs at each storage temperature were evaluated after 0, 2, 7, 14, 21 and 28 days of storage. Haugh units (HU), yolk index (YI), albumen pH (pHA), yolk pH (pHY) and angel food cake density (CD) were measured. Shell egg quality tended to be preserved better at below 2.2 °C, as high HU and YI values relative to eggs stored at 7.2 °C were determined on day 28. However, storage at ? 1.1 °C tended to cause the opposite effect, especially highly declined HU values over time. Significantly different HU values of shell eggs were measured after 14 days of storage, with eggs stored at 0.6 and 2.2 °C having the highest HU values, 80.42 and 77.97 respectively. CONCLUSION: A lower temperature limit for shell egg storage could be established between 0.6 and 2.2 °C, as both temperatures showed the highest HU values, 77.88 and 77.60 respectively, after 28 days of storage. Copyright © 2011 Society of Chemical Industry     

The effect of mincing method on the quality of refrigerated whiting burgers

Different mincing methods in the preparation of refrigerated whiting burgers had a significant effect on the products' quality during storage ( P  < 0.05). The burgers containing pre-cooked mince products (PCMP) had the lowest microbial load with longest sensory shelf life (10 days). Oven drying of dry ingredients with subsequent hygienic practices markedly decreased microbial load in final products, from 5.30 to <1.47 log CFU g⁻¹ for PCMP, 5.80–2.45 log CFU g⁻¹ for washed mince products (WMP), 5.65–2.14 log CFU g⁻¹ for unwashed mince products. The lowest trimethylamine and total volatile basic nitrogen (TVB-N) were observed with WMP reaching 14.7 and 42.03 mg per 100 g, respectively, at the end of storage. The differences in average surface colours of samples with different preparations and different additives were significant after mincing, but decreased after addition of ingredients, and after cooking. This study indicates the possibility of using pre-cooking as a method for formulated fish mince-based products as it had the highest consumer acceptance as well as longer sensory shelf life despite its higher values of trimethylamine and TVB-N compared with WMP.     

Mineral oil-chitosan emulsion coatings affect quality and shelf-life of coated eggs during refrigerated and room temperature storage

Effects of mineral oil (MO) and 4 emulsions (prepared with different emulsifier types) of MO and chitosan solution (CH) at a fixed ratio of MO:CH = 25:75 as coating materials in preserving the internal quality of eggs were evaluated during 5 wk at 25 °C and 20 wk at 4 °C. Generally, as storage time increased, Haugh unit and yolk index values decreased whereas weight loss increased. However, MO and/or 4 emulsion coatings minimized the weight loss (<1.5%) and preserved the albumen and yolk quality of eggs (with the final B grade) for at least 3 wk longer than those observed for noncoated eggs at 25 °C. At 4 °C, all coated eggs changed from AA to A grade after 5 wk and they maintained this grade for 10 wk (5 wk longer than that of noncoated eggs). Although refrigeration (4 °C) alone could maintain the B grade of noncoated eggs for up to 20 wk, coating treatments were necessary to keep the weight loss below 2%. Compared with 4 °C, the increasing weight loss showed stronger negative correlation (P < 0.01) with the decreasing Haugh unit (-0.46 to -0.89) and yolk index (-0.36 to -0.89) at 25 °C. The emulsifier type used in this study generally did not affect the internal quality of eggs. Salmonella spp. detection was negative for all coated and noncoated eggs. This study demonstrated that MO and MO:CH emulsion coatings preserved the internal quality, prolonged the shelf-life, and minimized weight loss (<2%) of eggs.     

The effect of filleting and ice application on the quality and safety of Atlantic bonito (Sarda sarda) at refrigerated storage

Filleting effect of refrigerated bonito with and without ice on the quality changes and food safety was investigated. Significant variations occurred (P < 0.05) in sensory, chemical and microbiological values amongst groups. The best sensory results were found for filleted bonito with ice (FBRI) with a shelf‐life of 13 days. While sensory values decreased significantly during storage, opposite situation occurred for both chemical and microbiological results (P < 0.05). The lowest total volatile basic nitrogen value was also observed with FBRI and was within the acceptable levels for 15 days as 17.86 mg 100 g^?1. All samples contained acceptable trimethylamine levels for 15 days despite unacceptable sensory values after certain days. Although filleting seemed to increase the lipid oxidation, ice application resulted in lowering thiobarbituric acid content. Histamine results closely supported sensory values in terms of legally permitted levels usually by set FDA. While WBR contained histamine value over EU permitted level as 113.78 ppm on the 7th day, the value for FBRI was 56.13 ppm on the 15th day. Histamine‐forming bacteria counts supported histamine formation in most groups, while total bacteria counts were in agreement with sensory results. This study suggests that using ice and filleting can improve shelf‐life of bonito stored at refrigerated temperatures in terms of food quality and safety.     

Effect of gelatin coating incorporated with cinnamon oil on the quality of fresh rainbow trout in cold storage

Cinnamon essential oil was used in gelatin coatings to maintain the quality of refrigerated rainbow trout fillets over a period of 20 days. Fish fillets were coated with a solution of 4% gelatin incorporated with cinnamon essential oil and then stored in refrigerator (4 ± 1 °C). Coating’s preservative effect was assessed periodically (every 5 days) by microbial analyses (aerobic plate count and psychrotrophic count), chemical determinations (total volatile basic nitrogen, thiobarbituric acid, free fatty acid) and sensory characteristics. When gelatin coating with cinnamon applied to the preservation of trout fillets, a reduction in the growth of total bacteria was observe after 15 days of storage. Fish fillets with gelatin coating containing 1%, 1.5% and 2% v/v cinnamon oil produced significantly lower (P < 0.05) total volatile basic nitrogen then gelatin‐coated fillets and control until 15 days of storage period (35, 22.86, 30.33, 57.76 and 53.26 mg per 100 g of fillet, respectively). The obtained results indicate that gelatin in the form of coating enriched with cinnamon oil is suitable for the preservation of rainbow trout fresh fillets and to efficiently maintain the quality attributes to an acceptable level during storage.     

The effect of chitosan coating incorporated with ethanolic extract of propolis on the quality of refrigerated chicken fillet

Chitosan is considered as a functional packaging component for maintaining the quality and increasing the shelf life of perishable foods include meat, poultry, fish, dairy products, and all cooked leftovers. The present study was conducted to evaluate edible coating of chitosan (2%) containing ethanolic extract of propolis (1% and 2%) on microbiological (mesophilic aerobic, psychrotrophic, lactic acid bacteria, coliforms, and Staphylococcus aureus counts), chemical (TBARS, TVN and Peroxide values) and sensory (odor, color, texture, taste, and overall acceptance) properties of chicken fillet. Microbial analysis showed that coating had a significant reducing effect on growth of bacteria during 12 days at 4 °C. Besides, the increase of TBARS, Total volatile nitrogen, and peroxide value of samples coated by chitosan and ethanolic extract of propolis was less than control group. According to our results, chitosan and propolis can be used to enhance the shelf life of fillet and maintain its quality.

Practical applications

Propolis is used for infections caused by bacteria, viruses, fungus, and by single‐celled organisms called protozoans. Propolis is also used as an antioxidant and anti‐inflammatory agent. Ethanol extract of propolis improve the properties of chitosan edible coating in chicken fillet preservation. The chitosan coating incorporated with ethanolic extract of propolis can improve the microbial, chemical, and sensory quality of food and enhance the shelf life of them by synergistic effects.     

Effects of pasteurisation and storage on quality characteristics of table olives preserved in olive oil

Two types of products obtained from the processing of Olea europaea cv ‘Taggiasca’ were monitored: pitted olives and olive paste preserved in monovarietal extra‐virgin olive oil of the same variety. The aim of this study was to follow the trends in the main physico‐chemical and sensory parameters related to the quality of these table olives and their covering oils, for simulation of the shelf‐life conditions. From all of the analyses carried out, it can be concluded that the optimum time of storage of these two products packaged in glass jars at room temperature (between 18 and 25 °C) and under artificial light and away from heat sources is approximately 9 months. After 9 months of storage, the covering oils were greatly affected by the contact with the broken fruit, which was accompanied by reductions in their antioxidant content due to the thermal treatment. The oxidative effects seen through physico‐chemical analyses are in agreement with the organoleptic analysis.