不同气体成分贮藏对大久保桃果实品质的影响

该文研究了大久保桃在不同气体成分下贮藏60 d以及出库后在20℃下货架期3 d后果实硬度、褐变指数、可溶性固形物含量、pH值、膜透性、出汁率和感官品质的变化。结果表明，1%的O₂对桃果实产生伤害，表现为表面色泽非正常变化、桃固有风味丧失并产生严重异味；(5～10)%O₂、(5～10)%CO₂气体成分能够在60 d的贮藏期内保持桃果实的品质，尤其是10%O₂＋10%CO₂处理较好地保持了果实的风味、质地和色泽，出库后果肉不褐变。与冷藏对照相比，气调贮藏能有效地延缓果实软化，抑制pH值和出汁率的升高，但对可溶性固形物的影响不大；在相同O₂浓度下，随CO₂浓度升高(<10%)，果实在货架期期间的软化程度、褐变指数下降幅度、pH值上升程度和膜透性增加幅度均增大，表明果实能够进行正常后熟。本研究推荐的大久保桃果实气调贮藏的适宜气体指标是10%O₂＋10%CO₂。     

不同组分气调包装牛肉冷藏保鲜效果的研究

为延长生鲜牛肉的货架期，保持良好色泽，该文研究了以不同比例组合的CO₂、O₂、N₂作为气调包装对低温保藏的新鲜牛臀肉品质的影响。以真空包装为对照，对保藏期间牛肉色泽、菌相变化、失重率、pH值、挥发性盐基氮等参数跟踪分析，确定最佳的气调包装组分为45% O₂、45% CO₂和10% N₂ ，温度0～4℃，在此条件下牛臀肉可以保藏20 d，并保持色泽稳定。     

不同气调包装方式对冷却猪肉在冷藏过程中的理化及感官特性的影响

冷却猪肉分别采用真空包装、CO+CO₂+N₂气调包装、高浓度O₂+CO₂+N₂气调包装和低浓度O₂+CO₂+N₂气调包装后，在(4±1)℃贮存至21 d，贮存过程中每周测定理化指标(pH值、TVB-N值、TBA值、汁液流失率)，并进行感官评定。实验结果表明：1)CO-MAP是目前冷却肉保鲜方法中比较理想的一种，采用CO-MAP的冷却猪肉在21 d的贮存过程中，不仅TVB-N值和TBA值低，红色稳定，而且无任何异味。2)真空包装的冷却猪肉TVB-N值和TBA值也比较低，但色泽呈淡紫色，汁液流失率高。3)含氧气调包装中，冷却猪肉的TVB-N值和TBA值相对较高，特别是脂肪氧化加速，鲜红色泽1周后很快变为褐色，并有不良气味产生，但汁液流失率比较低，所以含氧包装仅适合保质期在1周以内的冷却猪肉。     

气调包装技术用于虾皮保鲜的效果研究

为改进虾皮贮藏质量，延长货架期，研究了气调包装(Modified Atmosphere Packaging)对虾皮的保鲜效果。采用3种不同浓度配比的N₂和CO₂气体和真空包装等方法对虾皮进行包装，分别于5℃、室温和35℃下贮藏。检测虾皮感观、色差、菌落总数和脂肪含量。结果表明：低温有利于虾皮保鲜，高浓度CO₂气调贮藏能抑制虾皮中的微生物繁殖，减缓脂肪蚝蛤败速度，但CO₂浓度过高易使虾皮产生异味，影响感观品质。气调与低温结合可延长虾皮的保鲜期2个多月，推荐的气调气体比例为70%N₂/30%CO₂，低温冷藏。     

冷却牦牛分割肉酶嫩化技术研究

牦牛肉色泽鲜红，风味纯正，营养丰富，但肌纤维较粗，易出现“冷收缩”现象，使质地坚硬，嫩度下降。为提高冷却牦牛肉的嫩度，改善肉质，该研究将木瓜蛋白酶用于冷却牦牛分割肉嫩化，通过L₉(3⁴)正交试验选择出最佳嫩化工艺参数，即酶浓度9 mg/kg，处理温度15℃，处理时间3 h。采用注射嫩化法，真空包装、急速冷却后在0～4℃条件下贮藏。结果表明，木瓜蛋白酶可明显提高肉的嫩度，使剪切力值(48.44 N/cm²、肌纤维直径(8.03 μm)、失水率(5.91%)下降，口感改善，对冷却肉的贮藏性无影响(0～4℃，9 d)，操作方法简单，成本低，适合工厂化生产，实用性强。     

红富士苹果自发气调保鲜技术研究

采用5种不同保鲜膜包装，在0℃和10℃条件下，研究不同改性聚乙烯保鲜膜和聚氯乙烯保鲜膜、包装量对红富士苹果自发气调贮藏保鲜效果与原理，为红富士苹果冷藏保鲜和保鲜膜筛选提供依据。结果表明：不同红富士苹果保鲜膜包装内10 d左右O₂和CO₂浓度达平衡值。0℃条件下不同包装的O₂平衡值为12%～19%，CO₂为1.8%～5.0%，10℃条件下不同包装的O₂平衡值为5%～16%，CO₂为3.5%～8.0%。同样条件下2#保鲜膜包装内O₂最低、CO₂最高。各保鲜袋内虎皮病发生率高低顺序为：2#＞1#＞3#＞5#。包装量越大，温度越高，虎皮病发生率越大、乙醇和乙醛含量越高。利用富士专用保鲜膜和适宜的PE保鲜膜包装贮藏7个月，红富士苹果质量商品价值基本不变。     

厨余堆肥污染气体减排的工艺参数优化

好氧堆肥处理厨余垃圾具有规模灵活、参数易调整、工艺适配性高等优点,但存在发酵周期长且易产生污染气体等问题,严重限制了就近就地处理利用的推广。污染气体产生与堆体内氧气供应与利用直接相关,为提高发酵速率、减少污染气体排放,优化厨余垃圾堆肥的工艺参数,该研究采用三因素三水平正交堆肥试验L₉（3⁴）,探究粒径、含水率和通风速率三大因素对堆体温度、O₂、pH值、EC值、GI值以及污染气体（H₂S、NH₃、N₂O及CH₄）的影响。结果表明,当初始物料粒径为0.5～10 mm时能够显著加快堆肥进程,在第11 天时GI值即可达80%以上,有效地缩短了堆肥周期。通过对污染气体做极差以及方差分析发现,物料粒径对H₂S排放影响显著,含水率和通风速率对H₂S和N₂O排放影响显著。综合堆肥周期以及污染气体减排效果,厨余垃圾堆肥最优的工艺参数组合为：初始物料粒径为0.5～10 mm、初始含水率为60%、通风速率为0.2 L/（min·kg⁻¹）,研究结果可为厨余垃圾利用提供参考。     

干燥过程气体成分对蔬菜干制品质的影响

采用自制的QTM试验装置对蔬菜进行气调干制试验，研究了不同温度条件下气体成分对苦瓜片、萝卜丝和香葱干制品质量的影响。结果表明：采用N₂或CO₂进行气体调节，降低干燥过程气体的O₂含量，可明显提高蔬菜干制品叶绿素含量和降低干制过程维生素C质量分数的损失。用指数函数拟合蔬菜干制品的叶绿素含量与O₂含量间的关系，用幂函数拟合维生素C质量分数损失率与O₂含量间的关系，回归方程置信水平都大于95%。     

高氧处理对草莓采后腐烂和品质的影响

为探索高氧处理对草莓防腐保鲜的效果，该试验研究了40%、60%、80%和100% O₂及空气气流连续处理对“丰香”草莓在5℃、16 d贮藏期间果实腐烂和主要品质指标变化的影响。结果表明，高氧处理对果实总酸、可溶性固形物含量及果实表面色泽无明显影响。但60%～100%高氧处理可显著抑制草莓果实贮藏期间的腐烂，且O₂浓度越高，果实腐烂率越低，以100% O₂处理对果实防腐的作用最大。60%～100%高氧处理还可显著抑制果实失重，保持较高的果肉硬度和维生素C含量。40% O₂处理对草莓果实腐烂无显著影响。这些结果表明，高氧处理在草莓果实采后防腐保鲜中具潜在的应用前景。     

高氧对巨峰葡萄冷藏和货架期品质的影响

本文研究了高氧气调冷藏对巨峰葡萄品质、质构、贮藏性和货架寿命的影响。结果表明,与空气冷藏相比,高氧气调抑制了葡萄可溶性固形物、可滴定酸、维生素C含量和果柄耐拉力的降低,改善了葡萄的硬度、弹性、凝聚性、咀嚼性、风味和外观,减少了水分损失、腐烂、落果率和果梗褐变。与40%O₂+30%CO₂气调相比,除弹性、凝聚性、水分损失、落果和外观无显著差异外,80%O₂处理葡萄的保鲜效果更好。     

Irradiation and modified atmosphere packaging effects on residual nitrite,ascorbic acid,nitrosomyoglobin, and color in sausage

The present study was undertaken to evaluate the irradiation and modified atmosphere packaging effects on emulsion-type cooked pork sausage during storage for 4 weeks. CO(2) (100%), N(2) (100%), or 25% CO(2)/75% N(2) packaged sausage were irradiated at 0, 5, and 10 kGy, and residual nitrite, residual ascorbic acid, nitrosomyoglobin (NO-Mb), color values, and their correlation were observed. Irradiation significantly reduced the residual nitrite content and caused partial reduction of NO-Mb during storage. No difference was observed in ascorbic acid content by irradiation. Irradiation decreased the Hunter color a value of sausage. CO(2) or CO(2)/N(2) packaging were more effective for reducing residual nitrite and inhibiting the loss of the red color of sausage compared to N(2) packaging. Results indicated that the proper combination of irradiation and modified atmosphere packaging could reduce the residual nitrite in sausage with minimization of color change.     

气调和真空包装对腌制海鳗货架期的影响

该文主要考察25℃下气调和真空包装对腌制海鳗货架期的影响.4个样品分别是M1:空气包装(对照),M2:真空包装,M3:CO2/N2,40%/60%,M4:100%CO2,以挥发性盐基氮,三甲胺,pH值,硫代巴比妥酸值,菌落总数和感官为指标.结果表明,气调包装的货架期为20 d,真空包装为19 d,对照为16 d.对照组细菌增加很快,而M4增加最慢.挥发性盐基氮和三甲胺都随着储存时间延长而增加,在气调包装下的感官质量明显好于对照组.气调和真空包装,特别是100%CO2包装是保藏腌制海鳗的最有效方法.     

L-galactono-gamma-lactone dehydrogenase aand vitamin C content in fresh-cut potatoes stored under controlled atmospheres

L-galactono-gamma-lactone dehydrogenase (GLDH) activity and vitamin C content as ascorbic acid (AA) plus dehydroascorbic acid (DHA) were evaluated in five potato tuber cultivars (Agata, Altesse, Franceline, Manon, and Monalisa). The effect of fresh-cutting and subsequent refrigerated storage of Manon potato under different atmospheres (air, 20% CO(2) + air, 100% N(2), and vacuum packaging) on GLDH activity and vitamin C content was also determined. GLDH from the five potato tuber cultivars showed typical inhibition kinetics by high substrate concentration in the synthesis of AA from its physiological precursor L-galactonic acid-gamma-lactone (GL). GLDH activity was not correlated with the corresponding vitamin C content in any potato tuber cultivar. GLDH from all the cultivars presented a major isoform with isoelectric point (IEP) 5, which changed to IEP = 4.3 after minimal processing. In addition, the GLDH-catalyzed synthesis of AA by the new isoform showed typical Michaelis kinetics, in which the enzyme became more efficient to catalyze the reaction. Whether the change in the isoform pattern was due to either post-translational modifications or de novo synthesis of a new isoenzyme remains unanswered. Fresh-cutting increased GLDH activity from 4.7-fold (vacuum packaging) to 11-fold (air) after 6 days. In addition, 100% of vitamin C content was retained in air and decreased in the rest of atmospheres after this storage period, following the sequence vacuum packaging (89%) > 100% N(2) (78%) > 20% CO(2) + air (63%). This tendency was correlated with the corresponding GLDH activity detected in each storage atmosphere, except in the case of 20% CO(2) + air. Vacuum packaging proved to be the best storage condition, because fresh-cut potatoes did not turn brown and retained 89% of initial vitamin C content.     

去除冷却猪肉辐照异味方法初探

为了探索去除冷却猪肉辐射后异味的方法,研究了气调处理,吸附剂处理及气调与吸附剂组合处理对异味去除的效果,对吸附剂种类,添加量,吸附进程也作了分析。结果表明,预冷猪肉经60% O2 30% CO2 10% N2气调包装,或内置0.01 g/(50 g)肉小包装吸附剂（氯化锌/氧化锌）的薄膜包装后,辐照2.8 kGy,辐照后及冷藏期感觉不出辐照异味,猪肉品质正常。二者组合处理经4.2 kGy辐照后异味达不可察觉程度。     

样本预处理方式对罗氏沼虾碳和氮稳定同位素比值检测的影响

为研究样本预处理方式对罗氏沼虾碳和氮稳定同位素比值检测的影响,分别选用3种保存温度(常温23℃/15 d、冷藏2℃/90 d、冷冻-18℃/360 d)、2种取样方式(虾仁取样、整虾取样),以新鲜沼虾样本为对照组,对比不同样本预处理方式对罗氏沼虾碳稳定同位素比值(δ¹³C)、氮稳定同位素比值(δ¹⁵N)、碳氮比(C/N)的影响。结果表明,不同保存温度和不同取样方式对罗氏沼虾δ¹³C、δ¹⁵N、C/N的影响明显。与对照组相比,常温保存条件下的δ¹⁵N偏移量最大(1.31‰~13.16‰,平均值为6.02‰),冷冻保存条件下的δ¹³C偏移量最大(2.34‰~2.84‰,平均值为2.57‰),室温保存条件下的C/N显著增加(P<0.05),冷藏和冷冻保存条件下的C/N显著减少(P<0.05)。不同取样方式对罗氏沼虾δ¹⁵N、δ¹³C的影响还取决于保存温度,在冷冻保存条件下,整虾取样的δ¹⁵N、δ¹³C显著高于虾仁取样,而在常温保存条件下,整虾取样的δ¹⁵N偏移量显著低于虾仁取样。因此,常温(23℃)和冷藏(2℃)条件不适合保存罗氏沼虾、冷冻(-18℃)保存罗氏沼虾的时间不宜超过60 d,建议新鲜沼虾采集后应立即干燥并开展碳和氮稳定同位素检测。本研究结果为水产品碳和氮稳定同位素比值检测的样本预处理方式提供了参考。     

Effect of storage process on the sugars, polyphenols, color and microbiological changes in cracked Manzanilla-Aloreña table olives

The green cracked "seasoned" Manzanilla-Alore?a table olive is a specialty with a high demand when prepared from fresh fruits; however, when stored fruits are used, the product loses its green color, presents a brownish tone, and loses demand. Different alternative storage systems for preventing such changes and preserving the freshness of the fruits were studied, and their effects on sugar, polyphenol, color, and microbiological changes were analyzed. The application of two washing waters in the presence of different compounds before brining markedly decreased the sugar and polyphenol contents in the flesh, without negatively influencing the color; it also caused the inhibition of yeasts and lactic acid bacteria (except in treatments using sodium metabisulfite and saturated carbon dioxide (CO(2)) in the storage olive brines. Salicylic acid inhibited microbial growth during washings and storage. The best long-term color was achieved in the presence of sodium metabisulfite. A combination of two washing waters (containing 5% sodium chloride (NaCl) and 0.1% sodium metabisulfite or saturated CO(2)), followed by immersion of the fruits in 15% NaCl brine with 0.1% sodium metabisulfite or brine under saturated CO(2) added, led to the best storage conditions.     

低温液氮粉碎对绿茶粉品质影响

为减少茶叶粉碎过程中热敏性物质损失,提出茶叶低温液氮粉碎的新方法。该论文以绿茶为原料,在粉碎过程中添加液氮,比较常规粉碎与低温液氮粉碎方法处理对绿茶粉品质的影响。结果表明,与常规粉碎法相比,液氮粉碎法的出粉率高,所得的茶粉泡制成的茶汤在色泽、滋味和品质评分上明显占优,其水浸出物中茶多酚、咖啡碱、游离氨基酸、可溶性蛋白、可溶性糖等功效成分的质量分数分别高出25.12%、10.12%、9.50%、6.75%、12.63%、9.05%;2种茶粉的香气成分组成基本相同,但液氮粉碎法所得茶的茶粉中法呢烯、橙花叔醇、1H-吲哚、己酸-3-己烯酯、五甲基庚烷、苦杏仁苷、3-甲基丁酸2-甲基丙酯质量分数分别高出10.88%、13.70%、14.06%、5.61%、2.08%、24.39%、5.68%。表明液氮粉碎能较好的保留茶粉的品质,为液氮粉碎在绿茶加工中的应用提供参考。     

Characterization of the interaction between two food aroma components, alpha-pinene and ethyl butyrate, and ethylene-vinyl alcohol copolymer (EVOH) packaging films as a function of environmental humidity

The ethylene-vinyl alcohol copolymers (EVOHs) are well-known high oxygen barrier materials that are being used successfully in the design of packaging structures for oxygen-sensitive food or pharmaceutical products. Recently, there has been increasing interest in using EVOH materials to provide a high barrier to organic compounds as a means to reduce food aroma scalping. However, the barrier function of this family of materials diminishes significantly in humid environments, and it is supposed that so does the organic vapor barrier. In this work, a new sorption-based method to characterize the interaction between food aroma and polymer films for packaging as a function of relative humidity is presented and is used to determine the barrier to ethyl butyrate and alpha-pinene of EVOH at 23 degrees C. The results show that although EVOH is an excellent barrier to food aroma when dry, a property that even improves at low relative humidity (RH), the solubility and diffusivity of the compounds tested increase dramatically with humidity at medium to high water activities. However, even in the worst case (100% RH), EVOH outperforms low-density polyethylene (LDPE) as a barrier to organic vapors at least 500,000-fold.     

不同氮水平下CO2浓度升高对小麦土壤可溶性C、N和P的影响

采用FACE(Freeaircarbondioxideenrichment)技术,研究了不同N施肥水平下,大气CO2浓度升高对稻/麦轮作小麦季土壤可溶性C、N、P的影响。结果表明,高CO2使土壤可溶性C在小麦前期和0~5cm土层降低,成熟期增加,对水稻和小麦不同轮作季土壤可溶性C的影响不同。在低N和常规N处理下,高CO2使小麦分蘖期土壤可溶性N含量分别增加17.2%和18.9%,在其他生长期,土壤可溶性N含量降低9.8%~63.0%,拔节期降低幅度最大分别为63.0%和50.4%,土层0~5cm降低幅度>5~15cm土层;小麦季和水稻季一样需要增加N肥施用量。CO2浓度升高增加了土壤可溶性P的含量,其中低N处理增加幅度高于常规N处理,研究表明小麦生长不会受到P养分的限制。     

秸秆还田和免耕对土壤养分及碳库管理指数的影响研究

在四川盆地两种不同母质的土壤上,通过4年7季作物的田间试验研究了作物秸秆还田对稻田土壤NPK、土壤活性碳(CA)、微生物碳(CMB)、矿化碳(CM)和碳库管理指数(CPMI)的影响。结果表明,与对照相比,秸秆还田免耕和旋耕均可提高土壤全氮、全钾、碱解氮和速效钾,但各个处理间土壤磷素变化没有明显规律性。秸秆还田免耕、旋耕提高了土壤不同形态碳素含量和碳库管理指数;秸秆还田旋耕比秸秆还田免耕更能改善土壤有效碳库质量,CA、CMB、CM和CPMI分别提高4.33%～52.88%、8.69%～86.62%、20.64%～60.79%和18.41%～57.12%。相关性分析表明,运用土壤碳库管理指数表征土壤养份及碳素动态变化比土壤有机碳更具灵敏性。