气调包装对馒头品质及保鲜效果的影响

为延长馒头的货架期,研究了气调包装对馒头品质及保鲜效果的影响。在馒头冷却过程中辅以紫外照射,采用不同的气体条件(100%N_2,80%N_2和20%CO_2,50%N_2和50%CO2,20%N2和80%CO_2)对馒头进行包装,以空气包装为对照,测定馒头在25℃贮藏过程中微生物、理化及感官评定指标的变化。结果表明:紫外照射可有效防止二次污染。贮藏过程中馒头的菌落总数整体呈现上升趋势,包装顶空CO_2浓度越大,抑菌效果越显著,20%N2和80%CO_2气调包装的馒头在贮藏8 d后,菌落总数仍低于104cfu/g;馒头的水分含量和L*值逐渐下降;a*值、b*值和硬度呈现上升的趋势,感官上保持了馒头原有的色泽、风味和质地。高浓度CO_2的气调包装是保鲜馒头的理想手段,可将馒头的货架期延长至8 d以上。     

气调包装军曹鱼片在冰温保鲜期间的品质变化分析

为了探明气调包装军曹鱼片在冰温保鲜期间的品质变化,本文以空气包装和真空包装为对照,研究了气调包装军曹鱼片在冰温贮藏期间的K值、细菌总数、TVB-N、pH值、持水性、汁液流失率、感官评价、质构等品质指标的变化规律。结果表明:气调包装鱼片的鲜度指标K值达到初期腐败值60%和细菌总数的最大限值106 CFU/g是18 d,比空气包装和真空包装分别延长了6 d和2 d,达到TVB-N含量最大限值0.30 mg/g是23 d,比空气组和真空组延长了9 d和7 d。气调包装样品的汁液流失率、pH值升高速度较对照组缓慢;气调包装鱼片的持水率、感官品质、质构参数、色泽的变化较对照组小。综合比较表明,冰温气调包装军曹鱼片比空气包装和真空包装分别延长了8~10 d和2~6 d的贮藏期,说明冰温气调包装具有较明显的延缓军曹鱼片的腐败变质,更适合应用于高品质军曹鱼片的保鲜贮藏。     

Anaerobic Microbiology of Fresh Beef Packaged Under Modified Atmosphere or Vacuum

Beef was packaged under CO₂ containing < 500 ppm O₂ (MAP), vacuum, or air and stored at 0, 2, or 4°C. Samples were analyzed weekly for bacterial numbers using anaerobic plate count (pre-reduced medium and anaerobic chamber), -aerobic plate count, and anaerobic jar plate count (MAP samples only) methods. For both MAP and vacuum packaged samples, the anaerobic plate count was consistently greater than the aerobic plate count and for MAP samples the anaerobic plate count was consistently higher than the anaerobic jar plate count. Differences between plating methods were most frequent during the latter third of 0 and 2°C storage. Anaerobic isolates from MAP samples were most often lactic acid cocci and staphylococci. No clostridia were isolated from any of the treatments.     

静电纺丝纳米纤维抑菌吸水衬垫对气调包装中冷却肉贮藏品质的影响

气调包装冷却肉在贮藏过程中会发生汁液流出现象,不仅加速微生物的滋生,缩短货架期,同时也会降低其外观品质.基于此,本文利用静电纺丝技术包埋不同浓度(0％、5％、10％、15％、20％)丁香酚制备了一种高吸湿性抑菌吸水衬垫.在4℃气调包装条件下对市售无尘纸吸水垫和抑菌纳米纤维吸水垫的保鲜效果进行验证,并与未使用吸水垫的空白...     

Microbiological and Sensorial Quality Assessment of Ready-to-Cook Seafood Products Packaged under Modified Atmosphere

ABSTRACT:  The effects of modified atmosphere packaging (MAP) (30:40:30 O₂:CO₂:N₂ and 5:95 O₂:CO₂) on the quality of 4 ready-to-cook seafood products were studied. In particular, the investigation was carried out on hake fillets, yellow gurnard fillets, chub mackerel fillets, and entire eviscerated cuttlefish. Quality assessment was based on microbiological and sensorial indices determination. Both packaging gas mixtures contributed to a considerable slowing down of the microbial and sensorial quality loss of the investigated seafood products. Results showed that sensorial quality was the subindex that limited their shelf life. In fact, based primarily on microbiological results, samples under MAP remained acceptable up to the end of storage (that is, 14 d), regardless of fish specie. On the other hand, results from sensory analyses showed that chub mackerel fillets in MAP were acceptable up to the 6th storage d, whilst hake fillets, yellow gurnard fillets, and entire cuttlefish became unacceptable after 10 to 11 d. However, compared to control samples, an increase in the sensorial shelf life of MAP samples (ranging from about 95% to 250%) was always recorded.
Practical Application: Modified atmosphere packaging (MAP) is an inexpensive and uncomplicated method of extending shelf life of packed seafood. It could gain great attention from the fish industrial sector due to the fact that MAP is a practical and economic technique, realizable by small technical expedients. Moreover, there is great attention from the food industry and retailers to react to the growing demand for convenience food, thus promoting an increase in the assortments of ready-to-cook seafood products.     

苦荞面包配方及工艺参数优化

以苦荞面包的感官评定为判定标准,在单因素的基础上通过正交试验对苦荞面包的配方和生产工艺条件进行了优化,正交试验结果表明苦荞面包的最佳配方为:苦荞粉15%、砂糖20%、活性干酵母2.0%、起酥油12%;苦荞面包的最佳工艺条件为:醒发时间1.5 h、醒发温度32℃、烘烤温度170℃,烘烤时间15 min。在此条件下烤制的苦荞面包色泽金黄,质地松软,口感细腻,具有很好的感官品质。     

操作参数对组织化大豆蛋白产品特性的影响

低温脱脂豆粕的组织化加工是提高豆粕利用率的有效途径.以低温脱脂豆粕为原料,应用DSE-25型双螺杆挤压实验室工作站,分析了物料含水率、机筒温度、喂料速度、螺杆转速等操作参数对组织化大豆蛋白质构特性和理化特性的影响.结果表明:随着物料含水率的增加,咀嚼性下降,组织化度(TI)提高,在较高的物料含水率(45%、50%)条件下,氮溶解指数(NSI)较低,水分保持能力(WHC)较高;随着机筒温度的升高,TI和NSI逐渐增加,WHC先下降后上升,咀嚼性在140℃有明显降低趋势;随着喂料速度的增加,咀嚼性、TI、WHC、NSI下降;随着螺杆转速的增加,WHC和TI逐渐下降,咀嚼性、NSI基本不变;从理化特性和质构特性两个角度考虑,适宜的操作参数应为物料含水率45%～50%,机筒温度为140～150℃,喂料速度在30 g/min以下,螺杆转速为90 r/min.     

Physical, Chemical and Sensory Changes in Irradiated Fresh Pork Packaged in Modified Atmosphere

The effects of irradiation dose (0, 0.5 and 1.0 kGy), headspace oxygen (0, 10 and 20% O₂, balance nitrogen) and storage temperature (5, 15 and 25°C) on the physical, chemical and sensory changes in fresh pork were studied using factorial design experiments. Irradiation in the absence of oxygen extended the sensory shelf life of pork from 9 to 26 days at 5°C and from & lt; 2 to 2 days at 25°C. Oxygen in the package headspace combined with irradiation adversely affected physical, chemical and sensory characteristics of the end product.     

Effect of Carbon Dioxide Atmosphere on Staling and Water Relations in Bread

The effect of Modified Atmosphere Packaging (MAP on staling and on water relations in bread was evaluated. Application of CO₂ in MAP delayed staling of bread. Water sorption of bread packed in CO₂ was reduced compared to fresh bread and to bread packed in air. A water activity of 0.75 was found to be the boundary between the multilayer and the free water range of the isotherm. Spoilage of bread (microbial growth and staling) took place only above this water activity. Inverse Gas Chromatography was found to be unsuitable for investigating the effect of CO₂ on bread at the higher water activities because equilibrium conditions could not be achieved at these water activities.     

Shelf Life Assessment of Modified Atmosphere Packaged Turbot (Psetta maxima) Fillets: Evaluation of Microbial, Physical and Chemical Quality Parameters

Quality and safety of turbot fillets under modified atmosphere packaging (MAP) were assessed by microbial (total viable counts), physical (drip loss, pH, colour CIE Lab) and chemical parameters (total volatile basic nitrogen (TVBN), trimethylamine nitrogen (TMAN), biogenic amine contents). Three different atmospheres (MAP 1, 10/40/50 % O₂/CO₂/N₂; MAP 2, 10/60/30 % O₂/CO₂/N₂; MAP 3, 10/80/10 % O₂/CO₂/N₂) were tested. Packaged turbot fillets were stored at 2?±?1 °C and monitored over 30 days, at intervals of 5 days. Fillets from the control group, packaged with air (AIR), were the first to present signs of degradation reaching rejection threshold values for all evaluated parameters. In MAP fillets, total bacterial count was lower than 10⁶ cfu/g for a longer period. After 10 days of storage, MAP and AIR fillets showed significant differences (p?<?0.05) on the values of TVBN, TMAN and biogenic amines. MAP fillets presented a higher drip loss, and fillets in AIR became more yellowish (upper b* values) while those in MAP looked whitish for an increased period (upper L* values). All microbial, chemical and physical traits revealed the protective effect of the different MAP studied, especially those with a higher percentage of CO₂. MAP application added, at least, 5 days to shelf life of turbot fillets.     

气调包装酱卤鸭翅贮藏过程中菌群结构分析

运用传统细菌平板培养和聚合酶链式反应-变性梯度凝胶电脉方法研究气调包装酱卤鸭翅15 ℃贮藏过程中微生物菌群结构变化。细菌总数计数结果表明,产品生产的卫生条件较好,细菌初始污染菌数较低（小于2（lg（CFU/g）））,至贮藏第9天左右产品细菌总数超过4（lg（CFU/g））。变性梯度凝胶电脉指纹图谱结果表明,贮藏初期产品的初始污染菌主要为不动杆菌属,至贮藏末期,产品中的主要菌群有嗜冷杆菌、莫拉氏菌、链球菌等,其中嗜冷杆菌属成为产品贮藏末期的优势菌。     

Nondestructive Measurement of Oxygen in Modified Atmosphere Packaged Hams Using a Phase-Fluorimetric Sensor System

ABSTRACT: The phase-fluorimetric oxygen sensing system recently developed by our team was used for nondestructive measurement of oxygen content in the heasdspace of 4 types of ham slice products. The system allowed accurate measurement of oxygen levels in all types of ham packs in a contact-less nondestructive fashion; it worked satisfactorily under ambient light and in conditions of direct contact with packaged cooked ham slices and variation of sample temperature. A primary screening for oxygen content of the modified atmosphere packs revealed that a significant proportion of packs contained elevated levels of oxygen. The sensor demonstrated minor changes in calibration as a result of direct physical contact with food and prolonged exposure.     

包装材料对高氧气调包装冷鲜肉品质变化的影响

气调包装能有效延长冷却肉的货架期,但是不同阻隔性的包装材料对冷却肉的保质期影响差异显著,因此选用3种不同阻隔性的包装材料,对冷鲜肉进行高氧气调包装(35% CO2、65% O2),测定冷鲜肉在贮藏期的菌落总数、大肠菌群、色泽、挥发性盐基态氮、汁液流失率和pH值等指标,观察不同阻隔性的材料对冷却肉货架期品质的影响。结果表明：高氧包装条件下,高阻隔材料包装的冷却肉在贮存10d菌落总数已经超标,pH值在贮存期内处于二级鲜肉的范围内;中阻隔包装材料包装的冷却肉菌落总数对数值在保质期内未超过6(lg(CFU/g)),但是肉色保持的较好,感官评价相对较好,但是汁液流失较大;低阻隔包装材料低阻隔性的包装材料菌落变化最大,13d时菌落总数对数值达到6.46(lg(CFU/g)),肉的色泽相对较差,气味和总体可接受性也较差,因此,中阻隔性包装材料效果较好。     

鲜熟白切鸡气调锁鲜技术参数研究

为研究气调包装对白切鸡货架期及品质的影响,通过系统分析气调成分比例、顶空度对白切鸡贮藏过程中菌落总数、理化指标（质构、颜色、挥发性风味和包装盒膜凹陷程度）和感官指标（颜色、气味、滋味、组织状态）的影响,得出白切鸡最佳气调锁鲜技术参数以及对现行物流条件下新鲜度和货架期的延长效果。结果表明：最佳气调包装参数：顶空度为45%,气体比例为40% CO2+60% N2。在此条件和现行物流条件下贮藏过程中白切鸡品质降低,6~7 d时,白切鸡质构、颜色、挥发性风味、凹陷程度发生较大变化,而在11 d的贮藏过程中菌落总数和感官评价结果均在可接受水平范围。本研究结果对白切鸡的货架期延长及贮藏期间的品质保持具有重要意义,为白切鸡应用气调锁鲜技术提供了理论依据。     

高氧气调包装贮藏牛排肉色稳定性的蛋白质组学

为进一步了解高氧气调包装牛排贮藏过程中肉色稳定性变化的机理,本研究比较了腰背最长肌牛排在各贮藏时间点（0、5、10、15?d）的肉色指标变化以及蛋白质组学变化。结果发现高氧气调包装牛排的肉色稳定性随贮藏时间延长不断降低,这可能是贮藏期间牛排的高铁肌红蛋白还原能力和氧气消耗率显著下降所致;通过蛋白质组学分析,共发现了20?个在贮藏过程中发生显著变化的差异蛋白,其中有15?个蛋白与肉色密切相关,它们主要是一些参与糖酵解和能量代谢的酶类（丙酮酸激酶、3-磷酸甘油醛脱氢酶、果糖-二磷酸醛缩酶、果糖-1,6-二磷酸酶同工酶2、苹果酸脱氢酶和黄素还原酶）,这些代谢酶的表达量随贮藏时间延长发生了不同程度的下调,减少了烟酰胺腺嘌呤二核苷酸和还原型烟酰胺腺嘌呤二核苷酸磷酸的产生,进而降低了肉色稳定性;另外,高氧气调包装贮藏过程中肉色稳定性的降低可能也与肌红蛋白的表达量下调有关;高氧环境还可能会促使抗氧化蛋白2、热休克蛋白以及DJ-1蛋白的表达量上调以抵御肉品的氧化应激反应,这些蛋白也都与肉色指标紧密相关。这些发现表明贮藏期间高氧气调包装对牛排蛋白质组的影响将直接决定其肉色稳定性的变化。     

Development of Botulinal Toxin and Sensory Deterioration During Storage of Vacuum and Modified Atmosphere Packaged Fish Fillets

Toxin production by C. botulinum type E was studied in cod, whiting, and flounder filets packaged in air-permeable film, vacuum packages and packages flushed with N₂ or CO₂ during storage at 8°, 12° or 26°C. Cod and whiting filets were flushed with CO₂ and stored continuously at 4°C or cycled between 4° or 8° and 26°C. Cod and whiting fillets were flushed with gas mixtures and stored at 8°C or 26°C. Flounder deteriorated rapidly and was rejected by sensory evaluation prior to toxin detection during vacuum or modified atmosphere storage at 12°C and 8°C but after toxin detection at 26°C. Toxin was present either prior to or simultaneously with sensory rejection of cod and whiting fillets for all vacuum or modified atmosphere treatments and temperature regimens.     

Overall Quality and Shelf Life of Minimally Processed and Modified Atmosphere Packaged "Ready-to-Eat" Pomegranate Arils

ABSTRACT:  Minimally processed ready-to-eat pomegranate arils have become popular due to their convenience, high value, unique sensory characteristics, and health benefits. The objective of this study was to monitor quality parameters and to extend the shelf life of ready-to-eat pomegranate arils packaged with modified atmospheres. Minimally processed pomegranate arils were packed in PP trays sealed with BOPP film under 4 atmospheres including low and super atmospheric oxygen. Packaged arils were stored at 5 °C for 18 d and monitored for internal atmosphere and quality attributes. Atmosphere equilibrium was reached for all MAP applications except for high oxygen. As a general trend, slight or no significant change was detected in chemical and physical attributes of pomegranate arils during cold storage. The aerobic mesophilic bacteria were in the range of 2.30 to 4.51 log CFU/g at the end of the storage, which did not affect the sensory quality. Overall, the pomegranate arils packed with air, nitrogen, and enriched oxygen kept quality attributes and were acceptable to sensory panelists on day 18; however, marketability period was limited to 15 d for the low oxygen atmosphere. PP trays sealed with BOPP film combined with either passive or active modified atmospheres and storage at 5 °C provided commercially acceptable arils for 18 d with high quality and convenience.     

Headspace Volume and Percentage of Carbon Monoxide Affects Carboxymyoglobin Layer Development of Modified Atmosphere Packaged Beef Steaks

ABSTRACT:  Carboxymyoglobin (COMb) development of beef  Longissimus lumborum  as related to molecular CO availability and package headspace volume was evaluated. Steaks from six pairs of USDA Select strip loins were packaged in modified atmosphere packages with 0.2%, 0.4%, or 0.8% CO and 30% CO₂ and balanced with N₂ to obtain meat-to-gas ratios of 0.4, 0.7, and 1.1, and CO molar concentrations of 0.07, 0.10, and 0.20 mMol. Steak redness (CIE  a *), COMb layer thickness, percentage of CO in the headspace, visual display color, and bloom intensity scores were evaluated 4 and 7 d after packaging. Greater concentration of CO in a smaller headspace resulted in a thicker COMb layer compared with lesser concentration of CO in a larger headspace, regardless of moles CO available. The combined effects of concentration of CO and headspace volume had a greater impact on COMb development than millimoles of CO in the package headspace. Package headspace can be reduced and the concentration of CO can be increased without detriment to fresh beef color or consumer safety.