气改贮藏对桑果生理的影响

研究了气改(MA)贮藏对桑果生理的影响,结果表明:MA贮藏可显著地降低桑果的腐烂率,延缓VC的下降,抑制桑果呼吸强度、乙烯释放量、O_2生成速率和MDA含量,延缓SOD和CAT活性的下降,但对果实POD活性没有明显影响。     

Shelf-Life Extension of American Fresh Ginseng by Controlled Atmosphere Storage and Modified Atmosphere Packaging

American ginseng roots were treated with an antimicrobial agent, and stored under various CA (2,5, and 8% CO₂) or MA conditions to extend the shelf-life. Changes in respiration rates during CA storage, gas composition in packages, saponin and free sugar content, and other quality factors were monitored during storage. The respiration rate of ginseng increased rapidly during the first month of high CO₂ CA storage and then slowly decreased to stable levels after 3 mo storage. In MA studies, the equilibrium CO₂ concentration was attained after 20 days. There were no noticeable changes in appearance, saponin content and free sugars after 3 mo CA (5% CO₂) storage and MA packages.     

Modified Atmosphere Storage of Dungeness Crab (Cancer magister)

A modified atmosphere (MA) of 80% CO₂ and 20% air coupled with refrigerated storage was effective in extending shelf life of cooked whole Dungeness crab. Aerobic plate counts were lower over the storage period tested (25 days) for samples held in MA compared to controls held in air. Tissue pH decreased in MA samples, but increased in samples held as air controls (AC). There were significant differences in redox potential between groups, but these did not appear large enough to affect bacterial growth. Trimethylamine and ammonia values were similar for 14 days, then became higher in controls. There were no differences between treatment groups in thiobarbituric acid values, in textural properties as determined by Instron or in reflectance measurements. After removal from MA storage, the crab had a microbial shelf life that mimicked that of a fresh product.     

冰箱气调贮藏对水果的保鲜效果

为研究冰箱（5℃）气调贮藏对水果保鲜效果的影响,本研究选取了四种水果车厘子、草莓、红元帅苹果、蓝莓,在对照冰箱（常氧21%）和气调冰箱（O₂含量18~18.5%）中冷藏7 d,通过测定贮藏期间失重率、维生素C含量、花青素含量及果实表层细胞形态来检测气调冰箱的保鲜效果。结果表明：冰箱低温气调贮藏的四种水果保鲜效果最好,均能够显著（P<0.05）降低失重率,提高维生素C和花青素的保留率,改善果实的表观品质,减缓水果的感官品质劣变,维持水果的新鲜度,并维持水果良好的表皮细胞形态。因此,冰箱低温气调贮藏更有利于水果的保鲜。     

微环境气调对蓝莓贮藏期软化的调控作用

为探讨微环境气调对蓝莓贮藏期果实软化的影响,采用自发气调(mMAP)、1-甲基环丙烯(1-MCP)、微环境气调(mMAP+1-MCP)处理蓝莓,以未经处理的蓝莓为对照。将处理过的蓝莓置冰温库(-0.5±0.3) ℃贮藏,分别于贮藏0,20,40 d和60 d时测定果实硬度、细胞壁多糖含量、细胞壁降解酶活性和关键降解酶基因表达量。结果表明:与对照组相比,3个处理组均能显著降低果实的软果率(P < 0.05),其中mMAP+1-MCP处理效果最佳。贮藏60 d时果实硬度显著高于其它处理组(P < 0.05),维持较高的纤维素和原果胶含量,半纤维素在贮藏前期高于其它处理,而可溶性果胶含量在贮藏中前期保持较低水平。分析细胞壁降解酶,mMAP+1-MCP处理组贮藏40 d时纤维素酶(Cx)、多聚半乳糖醛酸酶(PG)和果胶甲酯酶(PME)活性最低,贮藏60 d时β-半乳糖苷酶(β-Gal)和α-L-阿拉伯呋喃糖苷酶(α-Af)活性显著低于其它处理组(P < 0.05)。正交偏最小二乘判别分析(OPLS-DA)表明,mMAP+1-MCP与其它处理组差异性指标为Cx和β-Gal活性。对这两种细胞壁降解酶基因的表达分析结果:mMAP+1-MCP处理可有效延缓蓝莓贮藏过程中Cx和β-Gal基因表达量峰值的出现时间。结论:mMAP+1-MCP形成的微环境气调环境通过延缓Cx和β-Gal基因表达量出峰时间,抑制贮藏后期Cx和β-Gal活性,保持果实的纤维素和原果胶含量,进而减缓果实的软化。     

自发气调包装对火龙果采后贮藏品质的影响

为探究不同自发气调包装对火龙果采后贮藏品质的影响,以火龙果为试验材料,采后通过4种不同的自发气调包装处理,对贮藏期品质指标进行定期测定。结果表明:自发气调包装能够有效地抑制火龙果贮藏期失重率、腐烂率、丙二醛(malondialdehyde,MDA)含量、相对电导率、多酚氧化酶(polyphenol oxidase,PPO)活性的增加,能较好地保持果实的可溶性固形物、还原糖、可滴定酸、VC含量,能较好地维持高CO_2低O_2的贮藏微环境,且PE40的保鲜效果好于PE20和PE30。总之,自发气调包装延缓了火龙果采后果实的衰老进程,保持较好地果实品质,其中,PE40的保鲜效果最好。     

不同气调包装对核桃仁贮藏品质的影响

将生核桃仁原料分别采用低O2高CO2的聚乙烯(PE)及复合材料(KNY17//CPE80)材料包装密封后,置于(2±1)℃冷库贮藏;以普通聚乙烯(PE)包装为对照,通过定期检测相关品质指标,研究不同气调方法对核桃仁的影响。结果表明：纳米包装和低O2高CO2的PE包装保鲜效果最好,两者均能显著抑制核桃仁过氧化值、酸价升高,保持良好外观品质,而且两种方法贮藏的生核桃仁加工成琥珀核桃仁后,经高温加速贮藏试验,过氧化值、酸价、羰基价都显著低于对照组。     

调味即食龙须菜去腥工艺及气调包装

目的：研究龙须菜调味即食海洋蔬菜的加工工艺。方法：以龙须菜为原料,分别采用甘草浓缩汁和臭氧水浸泡法去腥、醋酸软化、ZnCl2护色、CaCl2保脆等方法处理海藻,再经复合调味、杀菌、气调包装并运用一级动力学模型预测产品的货架期。结果：去腥最优工艺条件为甘草浓缩汁质量分数4%、浸泡15min、臭氧水质量浓度0.2mg/L、浸泡15min;研究出4种口味的复合调味龙须菜即食产品;最佳常温气调包装的复合气体组成为CO2:O2:N2=6:1:3;常温下,调味即食龙须菜产品的货架期为7个月。结论：研究的4种龙须菜即食产品各项品质指标良好,符合国家相关海藻即食食品标准规定。     

气调包装对百香果贮藏品质的影响

为探讨不同气调包装材料对百香果贮藏品质的影响,以‘紫香1号’百香果为试材,对其进行活性袋包装和普通聚乙烯袋包装两种处理,包装好后封口,并于温度（25±1）℃、相对湿度70%～80%的条件下贮藏;相同成熟度未进行包装的果实于相同条件下贮藏作为对照,监测贮藏期间百香果的质量损失率、可溶性固形物与可滴定酸含量、果皮的L*、a*、b*值、果皮缺陷指数及贮藏寿命。结果表明,与对照相比,两种气调包装均减缓了果实质量损失率的上升,延缓了果皮缺陷指数及其他与百香果后熟有关的物理化学变化,能延长贮藏寿命至少6 d;采用活性包装的百香果品质保持得更好,货架期更长。     

小麦气调储藏环境中氮气传递规律的研究

本实验在长9 m,宽6 m,高9 m的模拟中试仓,设计装粮线6.0 m,实储小麦高度5.7 m,N_2流量为30 L/m~3,恒定通入仓内。粮情测控智能终端测定18 min/次,当各点N_2浓度最高且持续稳定,停止向仓内通入N_2。结果表明:通过从离送气口的对称点位测得N_2在仓内传递速度均匀,因此可以均匀布点进行。水平方向距离送气口越远,N_2传递速度越慢。垂直方向距离越远,N_2浓度上升的越慢;离送气口越近,点之间N_2浓度差越大;离送气口越远,检测点之间浓度变化越相似。各点时间-N_2浓度均成显著正相关(p0.01),且检测点越接近,相关性越强,随着检测点之间距离的增加,相关性系数越来越小,说明N_2逐层传递,相邻检测点之间影响较大。通过对距离相同的水平与垂直检测点N_2浓度变化的分析,由显著性p=0.02(p0.05)得到垂直方向N_2浓度变化显著快于水平方向N_2浓度变化。     

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。     

气调储存对醇化环境及库存白肋烟品质的影响

为探索密封降氧对醇化环境及库存白肋烟品质的影响,以自然醇化42个月的湖北恩施成品白肋烟为材料,运用新型气调法,设置T1（1.5%～2%）和T2（7.5%～8%）2个低氧处理及1个常规处理CK,对其温、湿度及烟叶内在品质进行周期性对比。结果表明,与CK处理相比,T1和T2处理对温度影响不显著,但显著降低了相对湿度的变幅和变异系数。CK处理烟叶外观质量缓慢下降,而T1和T2处理则缓慢上升;T1、T2处理在12个月后,均显著提升了总糖含量,处理6个月后均显著提升了烟碱、钾、氯含量（除T1处理第12个月外）;T1处理烟叶感官质量总分在周期内呈现缓慢上升趋势,T2处理呈现先上升后缓慢下降趋势,CK处理呈现短暂上升后快速下降趋势;其中T1处理显著降低了烟叶NNN、NAT含量及TSNAs总量,而T2、CK处理间无显著差异。两低氧气调处理均对库存白肋烟的品质提升具有一定效果,且以T1处理综合提升效果更优。     

箱式气调对甜樱桃贮藏及货架品质的影响

为研究自发气调保鲜技术对甜樱桃贮藏效果的影响,以莎米托、菊红、拉宾斯、雷尼为试材,分析它们贮藏期及货架2 d后果实品质变化规律。试验结果表明,应用塑料箱式气调保鲜技术后,甜樱桃果实贮藏期延长,莎米托、菊红贮藏56 d,拉宾斯、雷尼贮藏49 d时,货架期果实品质仍呈缓慢下降趋势,尚具有商品及食用价值,之后果实硬度、可滴定酸度下降迅速,果柄保鲜指数、果皮褐变指数加重。     

箱式气调贮藏对巨峰葡萄果实质地变化的调控

以巨峰葡萄为试材,采用质构仪质地多面分析(TPA)方法对(0±0.5)℃贮藏条件下葡萄果实果肉质地参数变化规律进行研究,比较塑料薄膜和箱式气调贮藏对巨峰葡萄果实质地变化的调控效果。贮藏过程中葡萄果肉质地的变化直接影响其贮藏品质的优劣。气调箱内通入10%的CO2处理可以较好地调节适宜巨峰葡萄贮藏的气体环境,保持贮藏期间巨峰葡萄果实的硬度,有效延缓葡萄果实弹性、凝聚性、咀嚼性、回复性和黏着性的下降,提高葡萄果实的好果率。     

Monitoring the Egg Freshness During Storage Under Modified Atmosphere by Fluorescence Spectroscopy

A total of 207 intact brown-shelled eggs of the same flock (29 weeks of age) belonging to two treatment groups were stored in daylight at 12.2 °C and 87% relative humidity (RH): (1) 108 eggs and (2) 99 other eggs were kept in an atmosphere containing 2 and 4.6% of CO₂, respectively. The 18 remaining eggs have also been analysed directly when they were available in our laboratory to check the degree of freshness (aged of 1 day or less). Eggs of the two groups were analysed after 6, 8, 12, 15, 20, 22, 26, 29, 33, 40, 47 and 55 days of storage using front face fluorescence spectroscopy. The emission fluorescence spectra of aromatic amino acids and nucleic acids (AAA+NA; excitation, 250 nm; emission, 280–450 nm), fluorescent Maillard reaction products (excitation, 360 nm; emission, 380–580 nm) and the excitation spectra of vitamin A (emission, 410 nm; excitation, 270–350 nm) were scanned on thick albumen and egg yolk. For each treatment, the principal component analysis applied on the vitamin A fluorescence spectra allowed a good discrimination of eggs according to both their storage time and conditions, while more overlapping between egg samples was observed when the other intrinsic probes were investigated. These results showed that vitamin A fluorescence spectra could be considered as a good indicator of egg freshness kept only in 2% of CO₂.     

Storage Potential of Tomatoes Harvested at the Breaker Stage using Modified Atmosphere Packaging

Breaker tomatoes sealed in polymeric film (MAP) were stored at 15°C 23 days. A steady state of about 3.5-4.0 % O₂ and CO₂ was established. Mean concentrations of the gases within 24 hr of packaging were minimum 2.5 % O₂ and maximum 8.0% CO₂- Thereafter gas concentration moved gradually to a steady state; no evidence of anoxic conditions occurred. After 23 days of MAP storage fruit ripened normally under ambient conditions. Quality evaluations demonstrated that 15°C MAP storage permitted harvesting of breaker stage of ripeness tomatoes without reducing storage life to an unacceptable duration. MAP delayed changes in acidity, soluble solids, texture, color and polygalacturonase activity and resulted in substantial reduction in fruit weight loss and spoilage as compared to breaker fruit without film packaging.     

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。     

MA贮藏对采后茭白糠心和品质的影响

为了探讨MA贮藏对茭白保鲜的效果,研究(1±1)℃下MA贮藏对采后茭白品质和生理的影响.结果表明:采后茭白叶绿素酶活性增加1.4倍,使叶绿素含量下降43%;苯丙氨酸解氨酶(PAL)和过氧化物酶(POD)活性增加,导致茭肉纤维素和木质素含量分别增加32%和36%.MA贮藏不仅可显著降低茭白的呼吸强度和乙烯释放量,还可延缓叶绿素酶、PAL和POD活性的增加,茭白的总糖含量和叶绿素含量分别比对照高21%和34%,而空心指教、纤维素和木质素含量分别为对照的66%、92%和81%.表明MA贮藏可抑制茭白的黄化和糠心进程.