Assessment of egg freshness by prediction of Haugh unit and albumen pH using an artificial neural network

Eggs are a good source of high quality protein and knowing their quality (physical and chemical properties) during storage is of great importance. Thus, the aim of this research was to design a computer vision system to assess egg freshness during storage time. To this end, 210 intact eggs were collected and stored for 30 days under room conditions (25?±?2 °C and 20?±?3%). After imaging, every other day, some internal and external quality characteristics including yolk height, yolk and albumen pH, yolk and albumen density and Haugh unit (HU) were measured as destructive parameters and area index (D) egg weight as non-destructive parameters. Based on Pearson correlation coefficients, area index were significantly correlated with all destructive variables (p?<?0.05). In order to predict egg freshness, artificial neural network was trained by Levenberg–Marquardt, scaled conjugate gradient, Bayesian regulation, resilient and radial basis algorithms. The best result of artificial neural network for HU and albumen pH prediction was achieved by the Levenberg–Marquardt algorithm with the correlation coefficient of 0.93 and 0.87, respectively.     

Prediction of Egg Freshness and Albumen Quality Using Visible/Near Infrared Spectroscopy

Important changes occur in egg during storage leading to loss of quality. Prediction of these changes is critical in order to monitor egg quality and freshness. The aim of this research was to evaluate application of visible (VIS) and near infrared (NIR) spectroscopy as a rapid and non-destructive technique for egg quality assessment. Three hundred and sixty intact white-shelled eggs freshly laid by the same flock of hens fed with a standard feed were obtained. They were put under controlled conditions of temperature and humidity (T = 18 °C and RH = 55%) for 16 days of storage. Forty eggs were analyzed at day 0, 2, 4, 6, 8, 10, 12, 14, and 16. Transmission spectral data was obtained in the range from 350 to 2,500 nm. The non-destructive spectral data was compared to egg sample’s Haugh unit (HU) and albumen pH in terms of quality and to the number of storage days in terms of freshness. A partial least squares predictive model was developed and used to link the destructive assessment methods and the number of storage days with the spectral data. The correlation coefficient between the measured and predicted values of HU, albumen pH, and number of storage days were up to 0.94, R ² was up to 0.90 and the root mean square error values for the validation were 5.05, 0.06, and 1.65, respectively. These results showed that VIS/NIR transmission spectroscopy is a good tool for assessment of egg freshness and albumen pH and can be used as a non-destructive method for the prediction of HU, albumen pH, and number of storage days. In addition, the relevant information about these parameters was in the VIS and NIR ranging from 411 to 1,729 nm.     

贮藏温度变化对壳蛋新鲜度的影响

该文以新鲜罗曼粉壳蛋为研究对象,研究4个贮藏温度变化处理组壳蛋新鲜度指标的变化,分别于0、10、20、30 d检测所有实验组壳蛋失重率、气室高度、哈夫单位、蛋黄指数、浓稀蛋白比和蛋清pH。结果表明,贮藏10～30 d,处理组2、处理组3、处理组4的失重率显著升高(P<0.05),而气室高度和浓稀蛋白比显著降低(P<0.05),除对照组外,所有处理组壳蛋pH呈现先升高后下降的趋势,处理组3和处理组4的蛋黄指数下降趋势更为明显。对照组和处理组1壳蛋的哈夫单位、蛋黄指数和浓稀蛋白比显著高于(P<0.05)处理组3和处理组4。在贮藏10～20 d时,处理组2的壳蛋pH显著高于(P<0.05)对照组和处理组1。因此,如果前10 d常温贮藏温度≥20℃时,引起壳蛋失重率的增加和哈夫单位的下降,与低温(4℃)贮藏相比,采用贮藏温度变化(常温-低温)贮藏壳蛋更容易引起壳蛋新鲜度指标的下降。     

贮藏温度-时间变化对壳蛋新鲜度影响研究

该文以新鲜罗曼粉壳蛋为研究对象,研究5个贮藏温度-时间变化组壳蛋新鲜度指标变化,分别于0、10、20、30 d检测所有实验组壳蛋失重率、气室高度、哈夫单位、蛋黄指数、浓稀蛋白比、蛋清pH。结果表明,贮藏期间壳蛋失重率、气室高度和蛋清pH显著升高（P<0.05）,哈夫单位、蛋黄指数和浓稀蛋白比显著下降（P<0.05）。贮藏20 d时,处理组5壳蛋哈夫单位和蛋黄指数显著高于（P<0.05）对照组1、处理组1、处理组2和处理组3,而失重率、气室高度、蛋清pH较低（P<0.05）。贮藏30 d时,处理组5壳蛋失重率和气室高度显著低于对照组1、处理组1和处理组3（P<0.05）,蛋黄指数显著高于对照组1、处理组2、处理组3、处理组4（P<0.05）。除失重率、哈夫单位外,对照组2与处理组5壳蛋新鲜度指标整体差别不大。因此,除了壳蛋自身品质外,需要尽可能延长低温（4 ℃）贮藏时间,延缓壳蛋新鲜度指标劣变。     

Prediction of Poultry Egg Freshness Using Vis-Nir Spectroscopy with Maximum Likelihood Method

Crucial physio-chemical changes occuring in eggs during storage after laying lead to loss of egg freshness. In this research, a new method for prediction of egg freshness using transmission visible near infrared spectroscopy was investigated. For this purpose 300 eggs were stored at two control conditions: refrigerator (4–5°C, 75%RH) and room (24–25°C, 40%RH) then by special egg holder, transmission spectroscopy was measured. For two eggs groups, 25 eggs in each group, in six days were tested by spectroscopy, after that Haugh unit and air cell height was measured directly. The non-destructive visible near infrared spectroscopy spectral measurements from 300 to 1100 nm (832 length of wave) were done as well as Haugh unit, air cell height for each egg and created the database for both environments. Finally a maximum likelihood latent root regression algorithm was developed to predict Haugh unit and air cell height by spectrum observation. The database was randomly divided into two parts. Training data, was used for maximum likelihood latent root regression parameter tuning and training of the model and testing data, was used just for model evaluation. Results indicated that maximum likelihood latent root regression method showed good prediction ability with coefficient of determination (R²) value up to 0.82 and 0.86 for Haugh unit and air cell height, respectively for testing data set. The results showed this method was better in comparison with partial least square regression (R² up to 0.79 and 0.72 for air cell height and Haugh unit) which was already used for this prediction.     

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。     

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.     

Storage effects on dielectric properties of eggs from 10 to 1800 MHz

ABSTRACT:  The dielectric constant and loss factor of egg albumen and egg yolk over the frequency range from 10 to 1800 MHz were measured at 24 °C at weekly intervals during 5-wk storage at 15 °C. Moisture and ash contents of albumen and yolk, as well as Haugh unit and yolk index, were also measured. The dielectric constant and loss factor of albumen were higher than those of yolk. Linear relationships were evident between the log of frequency, below about 1000 MHz, and the log of loss factor of albumen as well as that of yolk. The dielectric constants of albumen and yolk at 10 MHz were lower than those of fresh albumen and yolk when eggs were stored at 15 °C for 1 wk. However, after 2 wk in storage these dielectric constants rose and remained at higher levels for the rest of the 5-wk period. At frequencies of 100 MHz and higher, the dielectric constant was essentially constant during the entire storage period. Storage had much less influence on the loss factor of either albumen or yolk. In general, the moisture content and ash content of albumen and yolk decreased slightly as eggs aged. The moisture content of yolk increased somewhat with storage, and there was a corresponding decrease in albumen moisture content. The freshness qualities, Haugh unit and yolk index, also decreased as eggs aged. No obvious correlation between dielectric properties and moisture content, ash content, Haugh unit, or yolk index was observed.     

Prediction modelling of storage time and quality measurements using visible-near infrared spectra of pasteurized shell eggs

A 12 week study was conducted on the egg albumen from both pasteurized and non-pasteurized shell eggs using visible-near infrared spectroscopy. Prediction models of the chemical changes detected in the spectra to the measurement of Haugh units (measure of interior egg quality) were calculated using principal component regression analysis. Additionally, the study sought to determine how pasteurization affects both shelf life and egg quality. 84 dozen eggs were involved in this study, with 12 dozen eggs scanned initially and biweekly for the remainder of the study. Eggs were stored at 4 °C throughout the study. Haugh unit measurements were conducted followed by the visible/near infrared spectra of the albumen. The changes in the spectra over the 12 week period were very subtle and consisted mainly of an approximately 10 % decrease in transmission across the 400–1,200 nm range. The 400–550 nm region can be used to distinguish between the spectra of control eggs and pasteurized eggs. The results suggest that spectral data can be used to confirm and/or predict the storage time of eggs. The correlation coefficients of the spectra models for storage time are 0.97 and 0.98 for the control (untreated) and pasteurized eggs, respectively. Correlation values for predicting Haugh units from the spectra of the samples resulted in less useful predictive models in this study, especially for pasteurized samples.     

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     

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.     

鸡蛋新鲜度指标与贮藏天数相关性研究

目的 分析鸡蛋新鲜度指标与贮藏天数的相关性, 确定新鲜度指标数值显著变化的时间, 建立新鲜度与贮藏时间相关性模型。方法 2 d为一个时间点, 设立12个实验组, 每组5枚鸡蛋, 按照标准中鸡蛋新鲜度评定指标重复3次测定鸡蛋相对密度、气室高度、哈夫单位、蛋黄指数、pH值、失重率。根据Pearson相关系数评价贮藏天数与鸡蛋新鲜度各指标之间的相关程度, Duncan法评价贮藏天数与鸡蛋新鲜度各指标之间的差异显著程度。结果 鸡蛋新鲜度各指标与贮藏天数之间显著相关(P<0.05), 各新鲜度指标数值出现显著变化的时间各不相同, 各天数之间的鸡蛋失重量、失重率差异显著(P<0.05)。结论 本研究所建立的鸡蛋新鲜度与贮藏时间的相关性模型, 可作为鸡蛋新鲜度评价模型。     

Prediction of Poultry Egg Freshness Using Ultrasound

A non-destructive ultrasound based method was used to develop a model for poultry egg freshness assessment. The proposed model can predict the Haugh unit, albumen thickness, air-cell height, and a number of other egg quality parameters by computing the ultrasound phase velocity within the egg material. For this purpose, the effect of the storage time on the ultrasound phase velocity within the poultry eggs together with the peak values of the transmitted ultrasound signals in the time and frequency domains were considered as indicators of egg freshness. Tests were conducted on eggs that were stored for five weeks in different storage conditions. The computed parameters were used to develop different models to predict the number of storage days for the egg samples. The results showed that the amplitude of the main peaks of the ultrasound signal in the time domain increased by the number of storage days. Moreover, there was a significant difference between the mean values of the phase velocities obtained at different times during the storage period. Comparing the results obtained for the eggs kept at the room temperature to those refrigerated showed that these variations were more significant for the eggs kept at room temperature.     

阻抗法检测鸡蛋新鲜度

鸡蛋在贮存过程中会发生一系列物理化学变化。在实际生活中,多以感官来衡量鸡蛋的新鲜度。本实验通过设立不同贮存条件,对不同温度(4、25℃)、不同相对湿度(75%、85%、98%)组合下的6组不同条件贮存过程中鸡蛋的哈夫单位、蛋黄指数、pH值以及相对应的阻抗进行检测。结果表明,在不同条件贮存过程中鸡蛋新鲜度指标哈夫单位、蛋黄指数、pH值与阻抗之间表现出了较好的相关性,建立标准曲线,通过阻抗值的大小对应标准曲线可计算鸡蛋新鲜度。阻抗法检测鸡蛋新鲜度具有操木作简便、快速、结果准确等优点,可为蛋品企业鸡蛋的保存提供一定的理论依据。     

壳聚糖涂膜对鸡蛋品质的影响

通过对新鲜鸡蛋涂擦不同质量浓度的壳聚糖溶液,旨在研究壳聚糖对鸡蛋品质的影响。试验将300 枚新鲜鸡蛋随机分成6 组,分别涂上0、0.5、1.0、1.5、2.0g/100mL 和2.5g/100mL 壳聚糖溶液,25℃条件下贮存5周。每周从每个处理中取10 枚鸡蛋测定鸡蛋失重率、哈夫单位、蛋黄指数和蛋清pH 值。结果表明,第5 周与第1 周相比,不涂壳聚糖的鸡蛋失重率和蛋清pH 值显著升高(P ＜ 0.05)、哈夫单位和蛋黄指数显著低(P ＜ 0.05) 。5 周时,与不涂壳聚糖的鸡蛋相比,所有涂壳聚糖的鸡蛋失重率显著降低(P ＜ 0.05),蛋黄指数显著升高(P ＜ 0.05);涂1.0、1.5、2.0g/100mL 和2.5g/100mL 壳聚糖的鸡蛋哈夫单位显著升高(P ＜ 0.05),蛋清pH 值显著降低(P ＜ 0.05);涂1.5、2.0g/100mL 和2.5g/100mL 壳聚糖的鸡蛋间比较,蛋质量损失率、哈夫单位、蛋黄指数和蛋清pH 值差异均不显著(P ＞ 0.05)。用0.5g/100mL 壳聚糖涂擦的鸡蛋5 周时降到C 级,相当于不涂壳聚糖的鸡蛋3 周时的级别;用1.0、1.5、2.0g/100mL 和2.5g/100mL 壳聚糖处理的鸡蛋5 周时降到B 级,相当于不用壳聚糖处理的鸡蛋2 周时的级别。该实验证明壳聚糖能够延长鸡蛋货架期。     

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     

MAP storage of shell hen eggs, Part 1: Effect on physico-chemical characteristics of the fresh product

The aim of this study was to compare some physico-chemical properties (O₂ and CO₂ in the package headspace, weight loss, pH, albumen and yolk water content and colour, Haugh unit) of non packed eggs and eggs packed in high barrier plastic pouches with three atmospheres (air, 100% N₂, 100% CO₂) during 28 days of storage at 25 °C. Modified atmosphere packaging (MAP) permitted a strong reduction of the weight loss from the product. While the greatest quality decline was observed for the control eggs (not packed), eggs packed in CO₂ maintained the initial values of Haugh unit during storage and the albumen pH was about 2 units lower than in the control group. Nevertheless, the light yellow colour of CO₂ sample albumen deepened and the shell gradually developed a powdery surface. MAP with 100% N₂ did not promote any additional benefits to the eggs in comparison with the product packed in air.     

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.     

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     

Quality Assessment of Poultry Egg Based on Visible–Near Infrared Spectroscopy and Radial Basis Function Networks

In this research the possibility of a non-destructive prediction of two main quality parameters of poultry egg using principle component analysis and radial basis function network by the transmission visible–near infrared spectroscopy method was investigated. The studied parameters include Haugh unit and air cell height as a function of a 5-week storage duration at room (25°C and 40% relative humidity) and refrigerator (5°C and 75% relative humidity) conditions. The spectra were interpreted and a radial basis function network model was developed for both storage conditions at wavelength ranges of 300–1100 nm. The developed models yielded a good prediction accuracy of Haugh unit for intact egg (R² value 0.745 and 0.76) as well as air cell height (R² value 0.835 and 0.844) for room and refrigerator conditions, respectively. Results of the experiment showed the developed model can be used in the prediction of egg freshness indices satisfactorily.