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。     

不同包装形式对市售壳蛋新鲜度的影响

该文以罗曼粉壳蛋为研究对象,探究市售壳蛋常用包装形式对于壳蛋新鲜度的影响,研究纸托散装不重叠组、散装重叠组、泡沫缓冲组、纸盒组和塑料盒组5种常见包装组壳蛋新鲜度指标变化,25℃贮藏30 d,分别于0、10、20、30 d检测所有实验组壳蛋失重率、气室高度和气室直径、蛋黄指数、哈夫单位、浓稀蛋白比、蛋清pH。结果表明,贮藏10～30 d,纸托散装重叠组壳蛋失重率（2.33%～7.35%）、气室直径（2.46～3.17 cm）、蛋清pH(9.24～9.28)显著升高（P<0.05）,而浓稀蛋白比（0.08～0.39）、蛋黄指数（0.27～0.41）显著下降（P<0.05）。纸盒组和塑料盒组壳蛋哈夫单位下降明显（P<0.05）,泡沫缓冲组和纸托散装不重叠组壳蛋具有较低的气室高度。泡沫缓冲组壳蛋失重率（0.62%～5.46%）、气室直径（2.02～2.62 cm）、蛋清pH(9.05～9.26)较低,而蛋黄指数（0.27～0.48）较高。进一步通过主成分分析能较好区分塑料盒、泡沫缓冲包装组与其他3个包装组壳蛋,新鲜度指标贡献情况具有一定差异。因此,不改变环境条件,采用泡沫缓冲...     

壳蛋新鲜度评价、影响因素及保持的研究进展

壳蛋新鲜度是衡量壳蛋品质的关键要素,本文梳理壳蛋新鲜度的评价方法、影响因素以及延缓壳蛋新鲜度指标劣变的方法,并对未来壳蛋新鲜度的研究方向进行展望。无损检测和有损检测法相结合能客观、动态、实时评价壳蛋新鲜度。蛋鸡年龄、饲料配方、贮运和环境条件等对壳蛋新鲜度影响较大,选用年轻蛋鸡、全营养饲料配方、低温贮藏、减少贮运过程中机械损伤可较好地维系壳蛋新鲜度特性。杀菌、包装、涂膜法可延缓壳蛋新鲜度指标的劣变,部分/全部采用绿色、高效、节能型非热杀菌方式,活性、可生物降解型智慧包装/涂膜技术,可有效抑制壳蛋微生物繁殖引起的腐败变质,延缓壳蛋新鲜度指标的劣变。未来壳蛋新鲜度的研究可以围绕无损检测技术、饲料配方、模拟实际生产、贮运销售环节,优化非热杀菌-包装涂膜技术等开展,以期为实现壳蛋品质提升与蛋品产业升级提供更多思路。     

贮藏温度对绞切加工猪肉肉糜新鲜度的影响

为了考察贮藏温度对绞切加工猪肉肉糜新鲜度的影响情况,通过试验分别对5,10,15,20℃贮藏温度下肉糜的挥发性盐基氮(TVB-N)含量、pH值、持水能力和肉糜色泽进行分析。结果表明,贮藏温度对猪肉肉糜的新鲜度品质影响明显,贮藏温度越低越有利于肉糜保鲜。考虑到贮藏成本,若贮藏时间不超过2d,可选择10℃的稍高贮藏温度;若贮藏时间稍长,超过3d或3d以上时,宜采用低温贮藏方案,如5℃或更低。研究结论可以为绞切加工后猪肉肉糜的储运设计提供参考。     

温度对南极磷虾粉贮藏性的影响

以感官、色泽、酸价、TBARS和胃蛋白酶消化率为指标,探讨了温度对南极磷虾粉贮藏性的影响。结果表明,在25、30、35℃三种贮藏温度下,贮藏温度越高,南极磷虾粉各项品质指标下降越快。三组样品在贮藏第165d后均未达到货架期终点,感官指标分别为0.92、1.01、1.21;酸价分别为2.03、2.19、2.29mg/g,胃蛋白酶消化率分别为92.58%、92.09%、91.51%,均符合鱼粉国家标准特级品指标;TBARS值均未超过鱼粉的20mg/kg限值。在实验温度范围内,贮藏165d后南极磷虾粉仍有较好的品质,表明船上生产的南极磷虾粉具有较好的贮藏性。     

温度对南极磷虾粉贮藏性的影响

以感官、色泽、酸价、TBARS和胃蛋白酶消化率为指标,探讨了温度对南极磷虾粉贮藏性的影响。结果表明,在25、30、35℃三种贮藏温度下,贮藏温度越高,南极磷虾粉各项品质指标下降越快。三组样品在贮藏第165d后均未达到货架期终点,感官指标分别为0.92、1.01、1.21;酸价分别为2.03、2.19、2.29mg/g,胃蛋白酶消化率分别为92.58%、92.09%、91.51%,均符合鱼粉国家标准特级品指标;TBARS值均未超过鱼粉的20mg/kg限值。在实验温度范围内,贮藏165d后南极磷虾粉仍有较好的品质,表明船上生产的南极磷虾粉具有较好的贮藏性。      

温度和壳寡糖对海胆贮藏品质的影响

研究温度和壳寡糖质量浓度对马粪海胆(Hemicentrous pulcherrimus)冷藏过程中品质变化的影响4℃和0℃条件的贮藏特性,并采用4种不同质量壳寡糖对马粪海胆进行处理,以感官评定、细菌总数、挥发性盐基氮(totalvolatile basic nitrogen,TVB-N)、pH值为指标,对其贮藏过程中的品质变化进行测定。结果表明:与4℃相比,0℃条件各项指标均较低(P<0.05),将该温度条件与壳寡糖处理复合后,保鲜效果明显增强(P<0.05),但不同壳寡糖质量组之间的各项指标差异不大(P>0.05),与4℃对照相比,0.1g/100mL壳寡糖质量浓度浸泡处理后冰温贮藏可延长货架期5～6d。     

贮藏温度变化对食品品质影响的研究现状

分析了温度与食品品质的关系,综述了国内外贮藏温度变化对食品品质影响的实验研究成果,指出了以往研究的特点,对今后在该领域的研究方向提出了建议。     

贮藏温度对鱿鱼品质变化的影响及其货架期分析

为探讨贮藏温度对鱿鱼品质变化及货架期的影响,研究了0、5、10、25℃贮藏条件下鱿鱼的色泽、pH、TVB-N、TMA、FA及TVC和感官分值的变化。结果表明,鱿鱼高品质期终点分别为357、180、118、19h,货架期终点分别为425、234、142、28h。贮藏过程中鱿鱼b*值、pH、TVB-N、TMA、TVC都有增加,FA随着贮藏时间呈先下降后上升的趋势。0、5、10、25℃贮藏的鱿鱼高品质期终点和货架期终点时的平均pH分别为（6.78±0.01）、（6.90±0.01）,TVB-N分别为（24.47±1.74）、（31.99±0.93）mg/100g,TMA分别为（6.71±0.90）、（10.23±0.30）mg/100g,FA分别为（1.65±0.94）、（4.22±0.34）mg/kg,TVC分别为（6.28±0.69）、（7.69±0.33）lgCFU/g。因此,贮藏温度越高,鱿鱼越容易腐败,货架期也越短,反之则对鱿鱼品质有利,可延长其货架期。      

贮藏温度对草莓浆理化成分和品质变化的影响

探明贮藏条件对草莓浆理化成分和品质的影响。研究了常温(25℃)、0、4、-18℃冷冻贮藏期间草莓浆花色苷、V_C、可滴定酸、可溶性固形物、风味的变化。结果表明,贮藏60 d,常温和4℃冷藏草莓浆花色苷保留率为12.56%和70.6%,0℃和-18℃冷冻贮藏草莓浆花色苷保留率仍在88%以上,常温和4℃贮藏V_C保留率分别为42.26%和73.21%,0℃和冷冻贮藏V_C保留率均为90%以上;可滴定酸和可溶性固形物在0℃和冷冻贮藏60 d内无显著变化;0℃和冷冻贮藏草莓浆的色泽明显优于常温贮藏;-18℃冷冻贮藏可以较好的保持草莓浆的酸味、甜味等味觉感官品质。经综合评价,0℃和-18℃冷冻环境条件有利于草莓果浆品质的保持,可显著延缓花色苷和V_C的降解,是较合适的草莓浆保藏温度,为草莓浆加工与保藏提供了参考。     

Effect of Shell Eggs Storage on Ovomucin Extraction

Ovomucin, one of the major egg white proteins, has wide potential applications in food, functional food and nutraceutical industries due to its unique physicochemical properties and bioactivities. A new two-step method was recently developed to prepare high purity ovomucin; in this study, effect of shell egg storage on ovomucin extraction was investigated. The composition of ovomucin extracts from egg white was determined by gel filtration chromatography. Both storage temperature and time could significantly (p < 0.05) affect the purity and yield of the ovomucin. After 9 weeks of storage at 4 °C, the content of the ovomucin in the extract decreased from 92.5% to 82.4%, and the yield of ovomucin decreased from 214 to 120 mg/100 g of egg albumen (egg white). After 5 weeks of storage at 22 °C, the content of ovomucin extract decreased from 92.5% to 73.0%, and the yield of ovomucin decreased from 214 to 112 mg/100 g of egg albumen. Increase in egg white pH during prolonged storage leading to degradation of ovomucin is very likely responsible for the decreased extractability of ovomucin.     

不同处理对鸡蛋保鲜效果的研究

采用加热、钙制剂涂膜以及二者复合对鸡蛋处理,然后将其在30℃高温下放置40d;以新鲜度中的哈夫单位和感官评定等为指标,研究加热处理、钙制剂涂膜处理以及二者复合处理对其保藏效果的影响。实验结果表明：加热处理的最佳条件是温度50℃、加热时间20min,此时保鲜效果好;复合涂膜组的哈夫单位变化低干加热处理组、钙制剂涂膜组和空白对照组,保鲜效果最好。此外复合涂膜组蛋清透明度、表面色泽、光亮度等一些感官指标均好于加热处理组、钙制剂涂膜组和空白组。3种方法处理的鸡蛋在30℃下贮藏40d,其哈夫单位仍具有比较大的值,保留在A级水平上。     

不同贮藏温度对鸡蛋呼吸强度及品质的影响

研究贮藏温度对鸡蛋呼吸强度和品质的影响。将鸡蛋样品置于不同温度的恒温贮藏库内贮藏一个月,进行呼吸强度和品质测定。结果表明：鸡蛋呼吸强度随贮藏温度升高而升高,4℃能有效地抑制鸡蛋的呼吸强度;4℃和25℃贮藏30d时,鸡蛋均有呼吸高峰出现,且冷藏蛋呼吸高峰值比25℃贮藏低约40%,峰期延迟3d;贮藏时间延长,鸡蛋质量损失率和气室直径增加,且高温下质量损失率增加幅度大于气室直径增加幅度;鸡蛋4℃条件冷藏哈夫单位降低较慢,第30天仍保持AA级,而25℃条件贮藏哈夫单位急速下降,第6天降到A级蛋下限。     

Effect of Storage Conditions on the Quality Attributes of Shell (Table) Eggs

In tropical countries like Nigeria, egg preservation is a serious problem. The common practice is to store under ambient condition due to lack of refrigeration facilities and erratic power supply. Four crates of fresh table eggs were bought from the University of Agriculture, Makurdi farm and preliminary investigations of egg weights, Haugh unit, pH and yolk index were carried out before storage and found to be within standard. Thirty eggs were stored under ambient condition with and without application of oil respectively. The other group of thirty eggs was refrigerated. The initial weights were in the range of 60 – 69 g which reduced drastically. All other quality indices like the Haugh unit, the yolk index and pH declined drastically within the four weeks of the storage especially those that were stored under the ambient conditions. Those stored under refrigeration and those that were oiled and stored under ambient conditions (32 + 2 °C) maintained high quality standards in all the quality indices evaluated. The microbiological result also showed higher bacteria, yeast and mould count on those stored under ambient condition with the initial count of 5.0 × 10³ at first week and 2.8 × 10⁷ at the fourth week while the oiled and refrigerated eggs had values of 5.0 × 10³ at week zero and 7.2 × 10⁴ at week four of storage respectively. It is suggested that application of oil on eggs before storage can be practised to ensure retention of good quality eggs especially in the tropics and most developing nations of the world.     

Combination of Super Chilling and High Carbon Dioxide Concentration Techniques Most Effectively to Preserve Freshness of Shell Eggs during Long-Term Storage

ABSTRACT:  This study was made to examine the combined effects of stored temperature and carbon dioxide atmosphere on shell egg quality. The shell eggs were packed into polyethylene terephthalate/polyethylene (PET/PE) pouches and stored at 0 °C (super chilling), 10 °C, and 20 °C, respectively for 90 d. The atmospheric carbon dioxide concentration was controlled to obtain the 3 concentration levels of high (about 2.0%), medium (about 0.5%), and low (below 0.01%). Changes in Haugh unit (HU) values, weakening of vitelline membranes, and generation of volatiles were analyzed to evaluate the freshness of shell eggs. Results showed that, compared with the other combinations, the technique of super chilling and high carbon dioxide concentration enabled shell eggs to be most effectively stored for 90 d, based on estimations of the statistical significances of differences in HU values, and on maintaining the initial HU values during storage. In addition, the storage of shell eggs using this combination technique was found to significantly prevent the weakening of the vitelline membrane based on the estimations of numbers of eggs without vitelline membrane breakage when eggs broke, and significantly lowered the incidence of hexanal in the yolk from exposure to the gas chromatographic-mass spectrometric analyses of volatiles. Thus, these results confirmed that the combination of super chilling and high carbon dioxide concentration was the most effective technique for preserving shell eggs during a long term of 90 d compared with other combination techniques.     

Storage of Shell Eggs Influences the Albumen Gelling Properties

Eggs from hens at 42 and 65 wk of age, respectively, were stored for time and temperature combinations of 0, 7, 10, and 14 d at 4, 12, 20, 28, and 37 °C in two experiments. The egg albumen was analysed for raw albumen quality parameters and dry matter content. Albumen gels prepared at either 85 °C or 90 °C were analysed for the textural properties corrected stress σ and Hencky strain ε at fracture point, σ_fandε_f , respectively, by uniaxial compression. The denaturation temperature, T_D, of ovalbumin in albumen samples was analysed by differential scanning calorimetry, DSC, and related to standards of N-ovalbumin and S-ovalbumin. Fresh egg albumen was characterised by the formation of gritty gels of poor water-holding capacity with lowσ_f and ε_fvalues. The stress and strain of gels at fracture were maximal after 14 d at 4 °C, and ε correlated significantly with ovalbumin T_Dfor gels prepared at 85 and 90 °C. The grouping of egg albumen samples with respect to the form of ovalbumin present (N-, intermediate, or S-) correlated with the egg mass loss during storage. Within the study, the storage temperature was more determining for the conversion of N-ovalbumin into S-ovalbumin than storage time.     

臭氧水杀菌对冰温贮藏牡蛎新鲜度和品质的影响

为明确臭氧水杀菌处理对生食水产品新鲜度和品质的影响,以新鲜牡蛎为研究对象,分析不同质量浓度(2,4,6,8 mg/L和10 mg/L)臭氧水作用不同时间(1,2,3,4 min和5 min)后,冰温贮藏牡蛎pH值、色差、感官指标、挥发性盐基氮(TVB-N)值和挥发性化合物等的变化情况。结果表明,质量浓度为4 mg/L的臭氧水作用2 min后,牡蛎肉的菌落总数(TVC)降至最低(3.58 CFU/g)。随着贮藏时间的增加,未处理组在第6天后TVB-N值>10 mg/(100 g),且增长速度显著大于处理组(P<0.05)。感官评定中,未被臭氧处理组在第7天感官评分低于8分,为不合格,而4 mg/L以上的臭氧水处理组,在第8天感官评分仍为合格,且未处理组牡蛎感官评分下降速度显著大于处理组(P<0.05)。各组牡蛎肉pH值在冷藏期间呈先下降后上升趋势,其中未处理组pH值由6.60下降至6.34后上升至6.86,上升趋势明显。冰藏期间,牡蛎肉的L值逐渐下降,a和b上升,与对照组相比,臭氧水杀菌处理保持了牡蛎肉的亮度。臭氧处理后牡蛎肉挥发性主成分贡献率为90.057%,能够反映牡蛎贮藏期间的主要特征信息及总体风味轮廓。结论:臭氧质量浓度4 mg/L为牡蛎适合的臭氧水杀菌浓度(作用时间2 min),且对风味无影响。臭氧处理是适用生食水产品加工的一种良好的非热杀菌处理方式。     

贮藏温度对大平顶枣品质的影响

为探究贮藏环境对大枣品质的影响,以朝阳大平顶枣为原料,在0℃、4℃、10℃、20℃温度下进行贮藏试验。通过测定贮藏过程中失重率、硬度、还原糖含量、可滴定酸含量的变化。结合低场核磁共振技术测定贮藏中水分的迁移,研究大枣的水分动态s变化的微观过程。结果表明:0℃和4℃低温贮藏能显著延缓大枣硬度的变化,抑制大枣贮藏期间失重率的增加。随着贮藏温度的降低,还原糖含量开始下降的时间延后。贮藏35 d时,0℃贮藏的大枣中可滴定酸含量分别比4℃、10℃、20℃的含量高9.90%、44.10%、54.50%。采用低场核磁共振技术检测大枣中水分迁移情况,测得自由水幅度下降顺序为20℃>10℃>4℃>0℃,温度越高,自由水在贮藏中的损失越多,下降的速率越快,从微观角度初探了大枣贮藏过程中变化机理。     

原料蛋的新鲜度对腌制期皮蛋品质的影响

为明确原料蛋的新鲜度对皮蛋腌制期间凝胶品质与蛋壳膜超微结构的影响,本实验以不同新鲜度的鸭蛋为原料,采用相同方法腌制皮蛋。通过扫描电子显微镜观察获取蛋壳膜的超微结构图像,并利用Image J软件进行处理获取蛋壳膜数据,同时测定皮蛋凝胶理化和质构指标,探究蛋壳膜孔隙度、凝胶pH值及含水率与凝胶质构参数硬度及弹性的变化规律及相关性。结果表明,在腌制的过程中,皮蛋蛋清的pH值呈现先下降后缓慢升高再急剧降低的趋势;皮蛋凝胶的硬度及弹性均呈现波动变化的趋势。原料蛋新鲜度越低,蛋壳膜孔隙度越高,腌制皮蛋成品的周期越短。蛋壳膜孔隙度与原料蛋新鲜度存在极显著负相关关系（P＜0.01）,与凝胶硬度呈现极显著正相关（P＜0.01）,与凝胶弹性呈现显著正相关（P＜0.05）。原料蛋新鲜度的降低对作为腌制液渗透通道的蛋壳膜产生影响,进而使皮蛋的品质产生差异,同时皮蛋的成品率也随原料蛋新鲜度的降低而下降。因此,原料蛋新鲜度与皮蛋品质存在紧密联系,本实验可为皮蛋腌制过程的品质变化提供新的研究思路,有利于皮蛋加工过程中的品质控制。