竹汁联合壳聚糖对鸡蛋涂膜保鲜效果的影响

用竹汁和壳聚糖制成的复合涂膜液对鸡蛋进行涂膜处理,以失重率、蛋黄指数、蛋清pH值、哈夫单位、相对密度为质量指标定期取样分析测定,研究复合涂膜在室温条件下对鸡蛋生理和品质的影响。结果表明,含竹汁的壳聚糖涂膜液能较好地保持鸡蛋的新鲜度和品质,尤其以1.5%的壳聚糖溶液联合100%的原竹汁制得的涂膜液保鲜效果最好,经此涂膜液处理后的鸡蛋室温下贮存35 d,失重率为1.89%,蛋黄指数为0.3,哈夫单位为61.559,蛋清pH值为8.23,相对密度为1.064 g/mg。     

含茶多酚的壳聚糖涂膜对鸡蛋保鲜效果的影响

用茶多酚和壳聚糖制成的复合涂膜液对鸡蛋进行涂膜处理,以感官指标、失重率、蛋黄指数、蛋清pH值、哈夫单位为质量指标定期取样分析测定,研究所制成的涂膜液在室温条件下对鸡蛋的保鲜效果。结果表明,和对照相比,含茶多酚的壳聚糖涂膜液能较好地保持鸡蛋的新鲜度和品质,尤其以1.5%的壳聚糖溶液联合200mg/kg茶多酚制得的涂膜液保鲜效果最好,经此涂膜液处理后的鸡蛋室温下贮存35d,失重率为1.89%,蛋黄指数为0.26,哈夫单位为60.109,蛋清pH值为8.20。     

不同涂膜保鲜法对鸡蛋保鲜效果的研究

分别采用壳聚糖涂膜、壳聚糖-玉米油复合涂膜、海藻酸钠-冰醋酸复合涂膜处理鸡蛋,以感官指标、蛋黄指数、蛋白系数、哈夫单位、气室直径和蛋白pH变化为评价指标,研究壳聚糖、壳聚糖-玉米油复合涂膜剂、海藻酸钠-冰醋酸复合涂膜剂处理鸡蛋,在30℃下贮藏21 d后对鸡蛋的保鲜效果。结果表明,壳聚糖-玉米油复合涂膜组优于壳聚糖涂膜组和海藻酸钠-冰醋酸复合涂膜组,贮藏21 d后其失重率为0.23%,蛋黄系数为0.167,蛋白系数为0.92,哈夫单位为62.8,气室直径为26.6 mm,蛋清pH为8.54。其中壳聚糖-玉米油复合涂膜处理组在贮藏21 d后失重率、气室直径、蛋黄指数、蛋白系数、哈夫单位都优于其他处理组。     

虫胶涂膜对鸡蛋保鲜效果的研究

以新鲜鸡蛋为原料,虫胶为保鲜膜材料,在温度为(20±2)℃,相对湿度为50%±10%的条件下,研究不同浓度的虫胶涂膜对鸡蛋的失重率、哈夫单位、蛋黄指数、蛋清pH、蛋黄pH的影响。结果表明:经过21d的储存后,虫胶涂膜处理后的鸡蛋比未处理鸡蛋保鲜效果好,其中以3.00%的虫胶涂膜效果最佳,其失重率为3.04%,哈夫单位为69.03,蛋黄指数为0.31,蛋清pH为9.45,蛋黄pH为7.07。     

木醋液复合保鲜膜对鸡蛋保鲜的影响

文章研究了木醋液、壳聚糖、海藻酸钠以及蔗糖酯4种复合保鲜剂对鲜鸡蛋保鲜效果的影响,以鸡蛋感官品质、哈夫单位、蛋黄指数、失重率、p H值、菌落总数为评价指标,通过单因素试验及响应面试验,得出木醋液复合保鲜膜最佳配方工艺为：1.0%木醋液、1.0%壳聚糖、1.5%海藻酸钠、1.5%蔗糖酯,其余为纯净水。在此条件下涂膜鲜鸡蛋后,36℃贮藏25 d,鸡蛋哈夫单位为65.74,蛋黄指数为0.31,失重率为2.67%,p H值为8.8,菌落总数为3.5×102 cfu/mL。以上指标与对照组相比,涂膜组鸡蛋的鲜度指标显著优于对照组。结果表明木醋液复合保鲜膜有效延长了鸡蛋的贮藏期。     

壳聚糖-玉米油复合涂膜剂对清洁鸡蛋的保鲜效果

为改善单一组分的植物油与壳聚糖涂膜剂的缺陷,将壳聚糖与玉米油以（CH-CO）0∶100、30∶70、40∶60、50∶50混合,并加入VE、柠檬酸、牛至精油、蔗糖酯复合成新型涂膜剂,分别在22 ℃和4 ℃进行贮藏研究。结果表明,相比于对照组、A组（CH∶CO＝30∶70）、C组（CH∶CO＝50∶50）,B组（CH∶CO＝40∶60）涂膜剂对鸡蛋保鲜效果更优。22 ℃贮藏45 d后,B组鸡蛋新鲜度仍为A级,质量损失率为0.39%,哈夫单位降低20.95,蛋黄指数下降22.08%,蛋清pH值上升0.63,挥发性盐基氮（total volatile basic nitrogen,TVB-N）含量增加1.01 mg/100 g。4 ℃贮藏10 周后,鸡蛋新鲜度相当于22 ℃贮藏33 d的效果;4 ℃贮藏结束时,B组鸡蛋质量损失率为0.54%,哈夫单位下降21.56,蛋黄指数降低9.97%,蛋清pH值下降0.46,TVB-N含量增加0.2 mg/100 g。因此,B组即以40%壳聚糖、60%玉米油、0.1%牛至精油、0.03% VE、0.015 g/100 mL柠檬酸、0.2 g/100 mL蔗糖酯组合的新型涂膜剂对鸡蛋的保鲜效果最优。     

鸡蛋内部品质与其呼吸强度的关系

贮藏期鸡蛋品质的变化与呼吸作用息息相关,为了进一步明确鸡蛋内部品质与其呼吸强度之间的关系,本研究选取同一品种的鸡蛋作为实验样本,利用呼吸测定仪测定鸡蛋的二氧化碳呼吸强度,通过SPSS 19.0软件分别分析鸡蛋哈夫单位、蛋白高度、pH值、黏度、蛋黄指数、蛋黄比例以及蛋黄色度与呼吸强度间的关系。结果表明：鸡蛋哈夫单位、蛋白高度及黏度与呼吸强度之间呈极显著正相关（P＜0.01）;pH值与呼吸强度之间呈极显著负相关（P＜0.01）;蛋黄指数、蛋黄色度与呼吸强度之间呈极显著正相关（P＜0.01）;而蛋黄比例与呼吸强度间相关性较小;此外,pH值与黏度、蛋黄指数、蛋黄色度间均存在极显著负相关（P＜0.01）;黏度与蛋黄指数、蛋黄色度之间呈极显著正相关（P＜0.01）;蛋黄比例与其他参数相关性较小。总之,在鸡蛋内部品质参数中,鸡蛋哈夫单位、蛋白高度、蛋黄指数、pH值、黏度及蛋黄色度对呼吸强度影响较大。     

可食性纳米TiO2-壳聚糖膜的制备及性能研究

以壳聚糖、苯甲酸钠、纳米二氧化钛为主要原料制备壳聚糖膜和可食性纳米TiO₂-壳聚糖复合膜，研究2种膜的性能及对鸡蛋保鲜效果的影响。结果表明：当苯甲酸钠浓度为0.4%、壳聚糖浓度为2.5%时，壳聚糖膜的性能最优，成膜效果最好；当纳米二氧化钛的添加量为2%时所制复合膜的性能最优。用制得的壳聚糖溶液和复合溶液对鸡蛋涂膜并进行理化性质检测，发现复合膜对鸡蛋有较好的保鲜效果。第14天时复合膜组的感官评价为浓蛋白较多，不散流，蛋黄呈扁球形，系带变细，鸡蛋气室高度为6.58 mm，失重率为7.23%，蛋黄指数为0.28，蛋清哈夫单位为72.4，蛋清pH值为8.63，鸡蛋总菌数为1.6×10⁴ cfu/mL。研究制备的复合膜对鸡蛋保鲜效果显著，为纳米二氧化钛在禽蛋保鲜领域的应用奠定了基础。     

壳聚糖/纳米银复合涂膜对鸡蛋的保鲜效果

将橘皮提取液还原制备的纳米银,按照0.5%,1.0%,2.0%的质量分数分别添加到壳聚糖溶液中,制成复合涂膜液,对鸡蛋进行涂膜,分别记为CS/Ag 0.5、CS/Ag 1.0、CS/Ag 2.0,纯壳聚糖涂膜组记为CS。将涂膜组与未处理组(CK1)、清水清洗组(CK2)置于温度25℃、相对湿度70%的条件下贮藏。定期对鸡蛋内容物的外观、失重率、气室高度、相对密度、哈夫单位(HU)、蛋清pH、蛋黄指数(YI)、鸡蛋内容物菌落总数以及蛋壳外表面微观形貌等指标进行测定。结果表明,纳米银在涂膜中的质量分数为1.0%时,涂膜鸡蛋可维持较低的失重率和气室高度,稳定的蛋清pH值,较高的相对密度、哈夫单位和蛋黄指数值。同时,该复合涂膜可显著抑制鸡蛋内容物中微生物的滋生,并能有效维持涂膜结构在贮藏期间的稳定性,从而提高保鲜效果的持续性。因此,CS/Ag 1.0组鸡蛋在25℃时的货架期可长达79d,相较于CS组延长了至少34d,而相较于CK1和CK2则至少延长了69d。     

气调包装、清洗涂膜及紫外杀菌处理对鸡蛋品质影响的比较分析

为研究不同贮藏方式对鸡蛋品质的影响,采用气调包装、清洗涂膜和紫外杀菌的组合处理方式,将新鲜鸡蛋分为6组,对其进行贮藏保鲜实验。在室温下贮藏42 d,测定鸡蛋失重率、哈夫单位、蛋黄指数、蛋清p H以及菌落总数的变化,并对蛋壳表面的真菌情况进行了初步的分析。结果显示:各气调包装组均能有效抑制失重率和蛋清p H的上升,并能有效抑制鸡蛋哈夫单位和蛋黄指数的降低,与对照组差异显著(p≤0.05);清洗涂膜能在一定程度上保鲜鸡蛋,但与对照组相比,鸡蛋的失重率、哈夫单位、蛋黄指数、蛋清p H等指标差异不显著;清洗涂膜和紫外处理对蛋壳表面的细菌具有良好的抑制作用;PCR测序结果显示蛋壳表面的真菌共计13种,以赛氏曲霉(Aspergillus sydowii)为主,占蛋壳表面真菌总量的80.91%。结论:经过清洗涂膜、紫外杀菌和气调包装复合处理的鸡蛋在贮藏期(42 d)内,失重率、哈夫单位、蛋黄指数、蛋清p H和细菌菌落总数等品质指标均优于其他处理组,能最大程度抑制鸡蛋腐败变质。     

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 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     

Efficacy of Antimicrobial Pullulan‐Based Coating to Improve Internal Quality and Shelf‐Life of Chicken Eggs During Storage

There has been a growing interest in the use of natural materials as a delivery mechanism for antimicrobials and coatings in foods. The aim of the present study was to evaluate the effectiveness of pullulan coatings to improve internal quality and shelf‐life of fresh eggs during 10 wk of storage at 25 and 4 °C. Three treatments of eggs were evaluated as follows; non‐coated (control; C), coated with pullulan (P), and coated with pullulan containing nisin (N). The effects of the pullulan coatings on microbiological qualities, physical properties, and freshness parameters were investigated and compared with non‐coated eggs. For non‐coated eggs, as storage time increased, yolk index, albumen index, and Haugh unit value decreased and weight loss increased. However, pullulan coatings (P or N) minimized weight loss (<1.5%) and preserved the albumen and yolk quality of eggs (with a final B grade) 3 wk longer than non‐coated eggs at 25 °C. At 4 °C, both P‐ and N‐coated eggs went from AA to A grade after 9 wk and maintained the grade for 10 wk (4 wk longer than that of non‐coated eggs). This study is the first to demonstrate that pullulan coatings can preserve the internal quality, prolong the shelf‐life, and minimize weight loss of fresh eggs.     

Effect of Plasticizer Concentration and Solvent Types on Shelf-life of Eggs Coated with Chitosan

ABSTRACT:  Effects of plasticizer concentrations (0, 0.5, 1.0, 1.5, and 2.0% glycerol) and solvent types (1% acetic and 1% lactic acid) on internal quality of eggs coated with 2% chitosan solution were evaluated during 5 wk of storage at 25 °C. In comparison of plasticizer concentrations, eggs coated with chitosan dissolved in acetic acid containing 2% glycerol showed significant reduction in weight loss compared with the noncoated eggs during 5 wk of storage. At 2% glycerol, the Haugh unit and yolk index values suggested that chitosan-coated eggs can be preserved for at least 3 wk longer than the control noncoated eggs during 5 wk of storage at 25 °C. Use of acetic acid rather than lactic acid as a chitosan solvent was more advantageous in view of shelf-life extension of eggs.     

Plasticizer types and coating methods affect quality and shelf life of eggs coated with chitosan

ABSTRACT:  Effects of different plasticizer types (glycerol, propylene glycol, and sorbitol) and coating methods (brushing, dipping, and spraying) on the internal quality and shelf life of chitosan-coated eggs were evaluated during 5 wk of storage at 25 °C. The Haugh unit and yolk index values suggested that chitosan coating, irrespective of the plasticizer types, extended the shelf life of eggs by almost 3 wk at 25 °C compared with noncoated eggs. After 5 wk of storage, plasticizer types did not significantly affect the quality (weight loss, Haugh unit, and yolk index) of chitosan-coated eggs. However, there was an observable trend indicating that use of sorbitol rather than propylene glycol and glycerol as a plasticizer was better in reducing weight loss (whole egg) of chitosan-coated eggs during a 5-wk storage. After a 5-wk storage, there were no significant differences in weight loss and weight of albumen and yolk among chitosan-coated eggs, regardless of the coating methods. However, both brushing and dipping methods yielded chitosan-coated eggs with better yolk (higher yolk index values) and albumen (lower pH) qualities than did the spraying method. During 3 to 5 wk of storage, the Haugh unit values of chitosan-coated eggs by the brushing method were higher than or comparable to those by dipping or spraying. Therefore, coating of eggs with chitosan using sorbitol as a plasticizer and by the brushing method may offer a protective barrier in preserving the internal quality and thus extending shelf life of eggs.     

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.     

Quality of eggs coated with oil–chitosan emulsion: Combined effects of emulsifier types,initial albumen quality,and storage

Effects of mineral oil:chitosan (MO:CH at 25:75) emulsions prepared with four different emulsifiers (2 water- and 2 oil-miscible) as coatings on the internal quality (weight loss, Haugh unit, yolk index, and albumen pH) of coated eggs were evaluated during 5 weeks at 25 ± 2 °C and 20 weeks at 4 ± 2 °C. Eggs with two initial albumen qualities [Haugh unit (HU): H = 87.8 and L = 70.9] were used. At 25 ± 2 °C, Haugh unit, yolk index, and albumen pH of all coated eggs decreased with increased storage time. Coated H- and L-eggs maintained an A-grade up to 4 weeks and 1 week, respectively. Weight loss of all coated eggs remained below 1.35% after 5 weeks of storage at 25 ± 2 °C. All coated eggs maintained an A-grade with less than 2.5% weight loss during 20 weeks of storage at 4 ± 2 °C. Emulsifier types marginally affected the internal quality of coated eggs regardless of storage temperatures.     

Effects of mineral oil coating on internal quality of chicken eggs under refrigerated storage

The selected internal qualities (weight loss, Haugh unit, yolk index, and albumen pH) of noncoated and mineral oil‐coated chicken eggs during 15 weeks of storage at 4 °C and/or during 5 weeks of storage at 25 °C were evaluated. Results indicated that, without refrigeration, the noncoated and mineral oil‐coated eggs rapidly changed from AA to C and B grades as measured by Haugh unit, respectively, after 5 weeks of storage. However, the AA quality of the noncoated eggs could be maintained under refrigerated storage (4 °C) for at least 5 weeks. The mineral oil coating and refrigerated storage (4 °C) synergistically minimised weight loss and preserved the albumen and yolk qualities of chicken eggs during a long‐term storage. At 4 °C, the mineral oil‐coated eggs preserved the initial AA grade for at least 15 weeks with l.19% weight loss.     

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     

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.