鲜切马铃薯复合褐变抑制剂组合的筛选

利用二次旋转组合设计筛选能取代亚硫酸盐的鲜切马铃薯复合褐变抑制剂组合,分析其对鲜切马铃薯贮藏期间PPO活性和褐变度的影响。结果表明,马铃薯切片最佳复合防褐剂配方组合为0.005%曲酸＋0.045%异抗坏血酸钠＋0.045%半胱氨酸(L-Cys)＋0.01% CaCl2＋0.2992% EDTA-2Na。该褐变抑制剂能够显著抑制鲜切马铃薯贮藏期间PPO活性,整个贮藏期间推迟PPO活性高峰时间6d以上;对鲜切马铃薯组织的褐变有明显延缓作用,处理组感官效果明显优于亚硝酸盐处理组和蒸馏水对照组,可以替代亚硫酸盐作为防褐剂用于鲜切马铃薯的生产和流通环节。     

辐照对峰甘板栗货架品质的影响

研究~(60)Co-γ射线辐照对真空包装峰甘板栗货架期指标的影响及其机制,初步确定延长货架期的最佳辐照剂量。通过~(60)Co-γ射线以0、0.5、1.0、3.0、3.5、4.0、4.5、5.0 kGy剂量辐照峰甘板栗,分别在贮存0、10、15、20、30 d时检测样品的微生物指标(菌落总数、霉菌及酵母数、大肠菌数、沙门氏菌数)、感官指标和理化指标。结果表明:辐照处理对峰甘板栗能够起到很好的杀菌作用;结合峰甘板栗感官品质评定及生理生化数据分析,辐照剂量为4.0 kGy时,可改善峰甘板栗感官质量并保持理化营养指标。初步认为,在4℃条件下,辐照剂量为4.0 kGy时,在微生物安全限量方面,使货架期延长至少20 d。     

热烫、温度及包装对鲜切芋艿品质及货架期的影响

对影响鲜切芋艿品质及货架期的主要因素热烫、贮藏温度和包装方式进行了初步研究。结果表明,热烫不利于贮藏;4℃为鲜切芋艿的最佳贮藏温度;真空包装对延长鲜切芋艿的货架期有明显效果。     

超声-ε-聚赖氨酸盐酸盐复合处理对鲜切苹果的保鲜作用

为提高鲜切苹果品质、延长货架期,探究超声-ε-聚赖氨酸盐酸盐复合处理鲜切苹果的最优参数及其保鲜效果。采用Box-Behnken设计,以菌落增长数为响应值,通过响应面法确定超声-ε-聚赖氨酸盐酸盐复合处理鲜切苹果的最佳参数。根据菌落总数、霉菌和酵母、色差、V_C含量结果,评价超声-ε-聚赖氨酸盐酸盐复合处理对鲜切苹果贮藏期间的保鲜作用。结果表明,超声-ε-聚赖氨酸盐酸盐复合处理鲜切苹果的最优参数为:超声时间为10 min、超声温度为40 ℃、ε-聚赖氨酸盐酸盐浓度为0.2 g/L,切分前与切分后处理实际测定值分别为1.59 lg CFU/g、1.71 lg CFU/g,与预测值相对误差分别为3.92%、5.59%,拟合度高,模型可靠。利用优化的条件处理的鲜切苹果在4 ℃贮藏期间,细菌、霉菌和酵母增长速度显著低于（P<0.05）对照,V_C未受到明显破坏,切分前超声-ε-聚赖氨酸盐酸盐复合处理组色差上升速度低于对照组。响应面法优化的超声-ε-聚赖氨酸盐酸盐复合处理鲜切苹果是可行的,其中切分前超声处理效果较好,货架期比对照组延长4 d。     

姜蒜浸提液与壳聚糖复合保鲜切分莲藕护色效果的研究

以新鲜莲藕为试材,采用单因素实验和正交实验方法,研究了不同浓度的生姜汁、大蒜提取液、壳聚糖及三者不同浓度复合的保鲜剂对鲜切莲藕贮运品质及保鲜效果的影响。结果表明:所试浓度的生姜汁、大蒜浸提液及壳聚糖处理切分莲藕贮藏15d后,多酚含量均有所降低,而丙二醛(MDA)含量有所上升;2.0%和4.0%的生姜汁、4.0%和6.0%的大蒜浸提液及2.0%的壳聚糖能显著抑制鲜切莲藕贮藏期间多酚的氧化和MDA的积累,在2℃下贮藏15d后无褐变和不良风味变化;复合保鲜剂的最佳配比是2.0%生姜汁、5.0%大蒜浸提液、2.0%壳聚糖、最佳浸泡时间为10min,复合保鲜剂处理的切分莲藕可在2℃下贮藏28d而不会出现风味劣变。     

酒精浸泡冷藏鲜印度块菌货架期评估、挥发性物质与细菌群落变化及其相关性

为探索延长鲜印度块菌货架期的简单有效的冷藏保鲜技术,本实验以我国产量最高的鲜印度块菌为对象,对其在4℃冷藏过程中的感官指标、菌落总数、主要营养组分质量损失率和挥发性物质含量进行研究,进一步采用高通量测序技术分析细菌群落变化,探究对鲜印度块菌香气贡献程度较大的挥发性物质和主要营养组分与细菌群落变化的相关性,通过16S rRNA测序测定鲜印度块菌冷藏过程中的优势腐败菌。结果表明,采用体积分数75%食用酒精速泡、真空包装后4℃冷藏,鲜印度块菌货架期可到30 d;在冷藏的38 d内鲜印度块菌的总糖、总蛋白、粗纤维相对含量与0 d相比明显下降,质量损失率明显上升,挥发性芳香物质含量明显下降,挥发性异味物质含量也明显增加。经高通量测序的细菌群落分析结果表明鲜印度块菌冷藏期间的优势菌门为Proteobacteria、Bacteroidetes、Actinobacteria、Firmicutes和Verrucomicrobia。基于属水平的冗余分析结果表明,在0～15 d营养组分（总糖、总蛋白和粗纤维）相对含量和特征性芳香物质（1-辛烯-3-醇、正戊酸正戊酯、乙酸乙酯、3-甲基丁酸乙酯、2-辛酮、1-...     

温度对鲜切马铃薯品质影响及货架期预测模型的建立

探究鲜切马铃薯在贮藏流通过程中品质的变化以及预测其货架期,将经二氧化氯（chlorine dioxide, ClO2）、柠檬酸、D-异抗坏血酸钠、氯化钙浸泡并真空包装的鲜切马铃薯分别置于 4 ℃、7 ℃、10 ℃条件下贮存,在贮藏期内对其进行感官评分,并对褐变度、失重率、菌落总数、硬度进行测定,在此基础上利用Arrhenius方程建立货架期预测模型。结果表明：鲜切马铃薯在 4 ℃、7 ℃、10 ℃下贮藏,其褐变度、失重率、菌落总数、硬度指标都随贮藏时间的延长而变化。其中褐变度,菌落总数以及硬度构建的货架期预测模型精确度都较高,决定系数R2都在 0.90以上,实测值与预测值的相对误差都低于10%,可有效预测鲜切马铃薯在4~10 ℃温度范围内的货架期。     

不同处理对鲜切茄子的保鲜性研究

采用电解水、壳聚糖、电解水+壳聚糖3种方式对鲜切茄子浸泡处理,并经真空包装装袋,室温下贮藏,比较3种处理方式对鲜切茄子的保鲜性。结果发现,随着贮藏时间的增加,各组鲜切茄子均发生不同程度的褐变;与对照组相比,经过壳聚糖处理的鲜切茄子的感官分值、失重率、褐变度、硬度和可溶性固形物的变化最快,而经过电解水处理的鲜切茄子保鲜效果最好。     

生物保鲜剂对提高鲜切荔枝果肉冰温贮藏品质的效果

研究了冰温贮藏条件下,乳酸链球菌素Nisin和溶菌酶2种生物保鲜剂对鲜切荔枝果肉冰温贮藏品质的影响。通过测定2种生物保鲜剂不同浓度及组合对鲜切荔枝果肉菌落总数、霉菌和酵母数、褐变度及多酚氧化酶活性变化可知,与对照组相比,经0.05%乳酸链球菌素和溶菌酶浸泡预处理可显著降低鲜切荔枝果肉贮藏期间菌落总数及霉菌和酵母的增加幅度;乳酸链球菌素对细菌的抑制效果优于溶菌酶,而溶菌酶对霉菌和酵母菌的抑制效果优于乳酸链球菌素,且溶菌酶对果肉有一定的护色作用。2种生物保鲜剂复配处理的综合效果优于单独处理,其中0.025%nisin+0.025%溶菌酶复合处理的抑菌效果和保持鲜切荔枝果肉色泽的效果均优于其他处理。     

纳他霉素处理对鲜切双孢菇褐变的抑制机理

为研究纳他霉素对鲜切双孢菇褐变的抑制机理,本实验分别采用去离子水（对照）、0.1?g/kg纳他霉素和复合试剂（0.1?g/kg纳他霉素＋10?g/kg?D-异抗坏血酸钠）浸泡处理鲜切双孢菇5?min,并于4?℃下贮藏,分析贮藏过程中多酚氧化酶（polyphenol oxidase,PPO）、酪氨酸酶（tyrosinase,TYR）活力和自由基清除率等多项生理指标。结果表明：纳他霉素和复合试剂处理均能抑制鲜切双孢菇贮藏过程中硬度下降及质量损失率、呼吸强度和相对电导率的上升,降低霉菌和酵母总数,延缓PPO和TYR活力的上升,维持双孢菇子实体VC、还原性谷胱甘肽、总酚和羟脯氨酸含量及谷胱甘肽还原酶和苯丙氨酸解氨酶的活力,有利于双孢菇保持较高的抗氧化酶活力、自由基清除率和总抗氧化能力,从而减轻双孢菇的褐变程度,延长其货架期,其中复合试剂处理的效果更佳。     

Effects of Soaking with Natural Additives in Combinations with Vacuum or Modified Atmosphere Packaging on Microbial Populations and Shelf Life of Fresh Truffles (Chinese Tuber Indicum)

The objective of this study was to evaluate the relative effects and interactions of combined soaking treatment using citric acid (CTA) and apple polyphenol (APP) at mild heating temperatures for the inactivation of the external and internal microflora (mesophilic aerobic bacteria, mesophilic anaerobic bacteria, and fungi) in Chinese Tuber indicum, as well as to analyze the microbiological and sensory changes under modified atmosphere packaging (MAP)‐ and vacuum atmosphere packaging (VAC)‐packed Chinese T. indicum stored at 4 °C for up to 55 d. Chinese T. indicum was soaked with CTA and APP alone or in combination for 10, 20, and 30 min at 35, 45, and 55 °C. A disinfection method using CTA and APP (3% CTA + 3% APP for 20 min at 45 °C) was obtained. Under this set of combination, the experimental values of microbial counts of mesophilic aerobic bacteria, mesophilic anaerobic bacteria, and fungi were 2.31 ± 0.4 log CFU/g, <1.0 log CFU/g, and <1.0 log CFU/g, respectively. Through the analysis of sensory qualities and microbial populations for MAP‐ or VAC‐packed Chinese T. indicum, the shelf life of soaked truffles was prolonged to 45 or 40 d, respectively. The synergistic effect of CTA and APP may provide valuable insight into the reduction of microorganisms on fresh truffles.     

Combination of high-intensity pulsed electric fields with natural antimicrobials to inactivate pathogenic microorganisms and extend the shelf-life of melon and watermelon juices

The effect of high-intensity pulsed electric field (HIPEF) combined with citric acid (0.5-2.0%, w/v) or cinnamon bark oil (0.05-0.30%, w/v) against populations of Escherichia coli O157:H7, Salmonella Enteritidis and Listeria monocytogenes in melon and watermelon juices were evaluated. Microbiological shelf-life and sensory attributes were also determined. Populations of E. coli O157:H7, S. Enteritidis and L. monocytogenes were reduced by more than 5.0log(10)CFU/ml in HIPEF-processed melon (35kV/cm for 1709 micros at 193Hz and 4 micros pulse duration) and watermelon (35kV/cm for 1682 micros at 193Hz and 4 micros pulse duration) juices containing 2.0% and 1.5% of citric acid, respectively, or 0.2% of cinnamon bark oil. In addition, these treatments were also able to inactivate mesophilic, psychrophilic and, molds and yeasts populations, leading to a shelf-life of more than 91 days in both juices stored at 5 degrees C. Hence, the microbiological quality and safety of these fruit juices by combining HIPEF and citric acid or cinnamon bark oil were ensured. However, the taste and odor in those HIPEF-treated melon and watermelon juices containing antimicrobials were significantly affected. Therefore, further studies are needed to decrease the impact on the sensory attributes by using antimicrobials.     

不同气调包装结合冰温贮藏对羊肉保鲜效果的影响

为延长鲜羊肉的保鲜时间,研究不同气体组分的气调包装对羊肉冰温贮藏过程中品质的影响。以真空包装为对照,比较75% O2＋25% CO2、75% N2＋25% CO2气调包装羊肉在－1 ℃冰温条件下贮藏过程中感官品质、色泽、汁液流失率、嫩度、挥发性盐基氮、pH值、微生物等品质指标的变化。结果表明：真空包装羊肉的汁液流失率显著高于2 种气调包装,而75% N2＋25% CO2气调包装羊肉的色泽和感官评分最差。75% O2＋25% CO2气调包装的保鲜效果最好,其色泽和感官评分最高,汁液流失率较小,pH值最低,－1 ℃冰温条件下贮藏42 d时,羊肉的菌落总数、假单胞菌菌数、乳酸菌菌数的对数值分别为5.91、5.95、5.23 （lg（CFU/g））,其中菌落总数指标符合国家二级鲜肉标准。因此,－1 ℃冰温条件下结合75% O2＋25% CO2气调包装可以使羊肉有效保鲜42 d,是较好的鲜羊肉保鲜方法。     

复合生物保鲜剂结合冰温贮藏对南美白对虾的保鲜效果

目的：研究复合保鲜剂结合冰温贮藏对南美白对虾的保鲜作用,避免其腐败变质,从而延长其货架期。方法：将复合生物保鲜剂处理过的南美白对虾贮藏在不同温度（4 ℃和－2.2～－1 ℃）条件下,通过pH值、感官评分、菌落总数、挥发性盐基氮含量、Ca2+-ATP酶比活力和硫代巴比妥酸含量指标的测定,对实验结果进行方差分析,确定最佳保鲜贮藏组合。结果：复合生物保鲜剂结合冰温贮藏延长了南美白对虾的货架期。结论：复合生物保鲜剂结合冰温贮藏对南美白对虾保鲜效果更佳,能使南美白对虾货架期达到21 d。     

Effects of electron-beam irradiation on the shelf life, microbial populations and sensory characteristics of summer truffles (Tuber aestivum) packaged under modified atmospheres

The effects of two doses of electron-beam irradiation (1.5 kGy and 2.5 kGy) on the microbial populations (total mesophilic aerobes, Pseudomonas genus, Enterobacteriaceae family, molds and yeasts) and sensory characteristics of Tuber aestivum packaged under modified atmospheres were monitored immediately after treatment, and weekly during 42 days of storage at 4 °C. Treatment with 1.5 and 2.5 kGy reduced the pseudomonads populations by 4.3 and 5.5 logs, respectively. Enterobacteriaceae counts decreased by 5.4 logs with the 1.5 kGy dose and counts below the detection limit (<1.0 log cfu/g) were obtained with the 2.5 kGy dose. Lactic acid bacteria and yeasts were less affected by the ionizing radiation treatments and they became the dominant microbial populations throughout storage with microbial counts up to 7.1 log cfu/g. The carbon dioxide levels inside the packages containing irradiated truffles were lower than those of the non-irradiated ones, suggesting a decrease in the respiration rate of the treated ascocarps. The treatments with 1.5 and 2.5 kGy e-beam did not negatively affect the sensory characteristics of truffles, but a visible superficial yeast growth was detected in truffles irradiated with 1.5 kGy at the end of their shelf life (day 28). Treatment with 2.5 kGy e-beam has prolonged the shelf life to 42 days, compared with 21 days for the untreated samples.     

生鲜鲩鱼片货架期预测模型的建立与评价

以生鲜鲩鱼片为对象,研究在15.0、10.0、5.0、-0.7℃贮藏的鲩鱼片在贮藏期间其细菌总数、挥发性盐基氮(TVB-N)和感官评定变化,以探讨鲩鱼片贮藏过程中的品质变化并建立其剩余货架期的预测模型。结果表明,随着贮藏时间的延长,鱼片肌肉的感官指标呈下降趋势,而细菌总数和TVB-N值呈上升趋势。用修正的Gompertz模型描述各温度下细菌总数的增长规律,优于一级化学反应动力学模型和Logistic模型。贮藏温度对细菌最大比生长速率μm和延滞时间λ的影响,采用Arrhennius方程描述,呈现良好线性关系,R2分别为0.956和0.990。在-0.7～15.0℃贮藏时,以细菌总数为标准建立货架期预测模型,所预测货架期分别为1.0、1.9、4.6、17.5d,与实测值的相对误差均小于12.5%,表明该模型可以快速可靠地预测-0.7～15℃贮藏生鲜鲩鱼片的剩余货架期。     

复合磷酸盐、谷氨酰胺转氨酶、大豆分离蛋白对新型鸭肉火腿保水特性和感官品质的影响

为研究复合磷酸盐、谷氨酰胺转氨酶、大豆分离蛋白对新型鸭肉火腿保水特性和感官品质的影响,通过单因素和L9（34）正交试验,以蒸煮损失、低场核磁共振自旋-自弛豫时间（T2）和感官品质为参考指标,确定最适添加量。结果表明：单独添加复合磷酸盐或大豆分离蛋白可以显著改善新型鸭肉火腿的蒸煮损失（P＜0.05）,添加大于0.5%的谷氨酰胺转氨酶会显著降低鸭肉火腿的保水性（P＜0.05）。通过正交试验优化得出的最佳添加量为：复合磷酸盐0.3%、谷氨酰胺转氨酶0.4%、大豆分离蛋白4%。应用此工艺,能够明显改善鸭肉火腿的保水特性和感官品质。     

不同包装对甜椒贮后货架期挥发性物质及理化品质的影响

以甜椒鲜果为原料,运用电子鼻结合顶空固相微萃取-气相色谱质谱（head space solid-phase microextractionand gas chromatography mass spectrometry,HS-SPME-GC-MS）联用技术,对甜椒10 ℃冷藏15 d后进行常温贮后货架期间挥发性成分进行测定,探究不同包装（无包装对照、微孔袋、20 μm聚乙烯袋包装）对其挥发性物质的影响,通过测定果实质量损失率、VC含量、糖酸比等指标分析不同包装对甜椒理化品质的影响。结果表明,电子鼻能够区分不同包装方式、不同贮后货架期的甜椒整体挥发性物质;GC-MS分析得出,甜椒的挥发性成分主要为酯类和醇类物质,且随着贮后货架时间的延长,酯类物质不断减少,而醇类物质则不断上升,对照、微孔袋、20 μm聚乙烯袋3 组酯类相对含量分别下降了47.33%、23.43%和51.39%,醇类相对含量分别上升了68.73%、56.80%和72.96%,说明微孔袋包装可以有效延缓酯类物质的损失以及延缓醇类物质的增加,有效改善甜椒常温货架期间的香气成分,其保鲜作用优于对照和20 μm聚乙烯袋组;相同贮后货架期下微孔袋组的VC含量和糖酸比均最高,微孔袋、20 μm聚乙烯袋包装组之间质量损失率差异不显著（P＞0.05）,但明显小于对照组（P＜0.05）,说明微孔袋包装对甜椒贮后货架期理化品质的保鲜作用优于对照和20 μm聚乙烯袋组。     

丁香精油-壳聚糖复合可食性膜对生肉糜保鲜效果的影响

研究丁香精油-壳聚糖复合可食性膜对生肉糜冷藏期间感官品质和货架期的影响。测定生肉糜样品在（4±1）℃冷藏期间细菌总数、pH值、硫代巴比妥酸反应物值、高铁肌红蛋白含量以及感官品质随时间的变化情况。结果表明：添加丁香精油可提高壳聚糖可食性膜的抗菌和抗氧化活性。包裹丁香精油-壳聚糖复合可食性膜可有效抑制生肉糜菌落总数和高铁肌红蛋白含量的增加;同时还可抑制贮藏过程中的脂肪氧化,对感官品质具有良好的保持作用,在（4±1）℃条件下贮藏期可达10～12 d,明显提高了生肉糜贮藏过程中的品质和货架期。丁香精油-壳聚糖复合膜可作为可食性包装膜延长生肉糜冷藏期间的货架期。     

Effects of electron-beam and gamma irradiation treatments on the microbial populations, respiratory activity and sensory characteristics of Tuber melanosporum truffles packaged under modified atmospheres

The effects of electron-beam or gamma irradiation (doses of 1.5 kGy and 2.5 kGy of either one) on the microbial populations, respiratory activity and sensory characteristics of Tuber melanosporum packaged under modified atmospheres were monitored immediately after treatment, and subsequently every seven days during 35 days of storage at 4 °C. Treatments with 1.5 and 2.5 kGy reduced the total mesophilic aerobes counts respectively by 4.3 and 5.6 log cfu/g for electron-beam treatment, and by 6.4 and 6.6 log cfu/g for gamma irradiation. Other microbial groups studied (Pseudomonas genus, Enterobacteriaceae family, lactic acid bacteria, mesophilic aerobic spores, molds and yeasts) were not detected after the treatments. A decrease in the respiratory activity was detected in all the irradiated batches, indicating that the carbon dioxide levels were lower and the oxygen levels higher than those of the non-irradiated ones. Two species of yeasts, Candida sake and Candida membranifaciens var. santamariae, survived the irradiation treatments and became the dominant microbial populations with counts of up to 7.0 log cfu/g. The growth of these microorganisms was visible on the surface of irradiated truffles from day 21 onwards, affecting the flavor and the general acceptability of the ascocarps. Moreover, a watery exudate was detected in the treated truffles from the third week onwards, so the application of irradiation treatments in doses equal to or above 1.5 kGy did not preserve the quality characteristics of T. melanosporum truffles beyond 28 days.