蔗糖基聚合物涂膜对樱桃番茄保鲜效果的研究

以不同浓度的蔗糖基聚合物溶液作为樱桃番茄的涂膜保鲜剂,研究其对樱桃番茄采后生理的影响。结果表明,蔗糖基聚合物涂膜能降低樱桃番茄的呼吸强度,抑制VC含量以及过氧化物酶和多聚半乳糖醛酸酶活性的升高。      

聚乳酸薄共聚膜对樱桃番茄自发气调保鲜的影响

为提高自发气调包装(spontaneous control modified atmosphere packaging,SMAP)保鲜效果,采用化学改性方法制备高气体透过性及二氧化碳/氧气(CO_2/O_2)选择性的可降解聚乳酸嵌段物(PLGLx G20),制备薄膜并用于樱桃番茄的低温SMAP包装,通过对包装内气体浓度、果实的感官品质、营养成分等分析考察薄膜的保鲜效果。结果显示,储藏初期CO_2浓度迅速升高,O_2浓度迅速降低,约5 d后包装内的气体达到平衡,其CO_2浓度随着PLGLx G20的CO_2透过系数的增大呈阶梯型减小,薄膜表现出对内部气体的控制能力。与无包装和聚乳酸包装组相比,PLGLx G20包装内维持了相对低O_2高CO_2的气体环境,其中PLGL35G20包装在6 d后达到较适宜番茄保鲜的体积分数为3%～5%CO_2和3%～4%O_2平衡浓度,抑制了强烈的有氧呼吸,果实在20 d内维持了较好的感官品质和营养成分。该研究表明,PLGLx G20薄膜对果蔬具有良好的保鲜效果,对拓宽可降解材料在食品包装中应用具有一定意义。     

EBR处理对甜樱桃贮藏期间品质及生理特性的影响

以甜樱桃\     

模拟超市销售期间圣女果质构特性变化的研究

采用TPA(texture profile analysis)测试法和感官评价相结合的方法,测定模拟超市销售期间圣女果货架期质构特性和品质变化指标,并对其相关性进行分析。结果表明,TPA测试圣女果的各项质构参数能够在不同方面反映圣女果在货架期间的品质变化特性,货架期4d是圣女果质构特性及其它品质变化的拐点,货架期6d时所有质构特性及品质会急剧下降。质构参数硬度与感官评分呈极显著正相关(P<0.01),咀嚼性与感官评分呈显著正相关(P<0.05),表明主要质构参数测定可用于预测圣女果在此条件下的品质变化。     

Efficacy of dual-frequency ultrasound and sanitizers washing treatments on quality retention of cherry tomato

Refrigeration is an effective means of reducing losses in fresh fruit; however, its efficacy as a means of preservation is mostly limited to crops that are not vulnerable to chill injury. Cherry tomato is one of these crops where other supporting processes or storage alternatives are sought. The effect of 10-min post-harvest treatment of cherry tomato with individual or combined application of dual-frequency ultrasound (20/40 kHz) and chemical sanitizers was investigated. The sanitizers used are 200 mg/L sodium dichloroisocyanurate (SD), 40 mg/L peracetic acid (PAA), 40 mg/L peracetic acid with 5% H₂O₂ (PAAH), and 5% hydrogen peroxide. The results showed that the treatments significantly reduced the natural microbiota (aerobic mesophiles and yeasts and molds) within the values of 0.29–3.10 log CFU/g. The highest inactivation was observed for the PAAH and ultrasound when applied as an individual (2.08–2.32 log CFU/g) and combined (3.07–3.10 log CFU/g) treatment. Also, the ultrasound and combined treatment resulted in higher retention of the total phenolic, and flavonoid contents, but with a loss in firmness of the cherry tomato. Nevertheless, during storage, the treatments when compared with the untreated samples, impede the loss in firmness. The other quality parameters such as pH, total soluble solids, titratable acidity, and maturity index were not affected, which signified that irrespective of the treatment, similar changes take place on the fruit during storage, especially in both control and chemically treated fruit. The combination of 40 mg/L PAAH and 20/40 kHz for 10 min caused ≥3-log CFU/g reduction of the natural microbiota. It mitigated the senescence of the cherry tomato during the refrigerated storage (4 °C), which thereby increased the shelf-life. The results obtained at the end of the storage thereby indicated that the combined treatments could guarantee microbial safety and retain the quality of the cherry tomato.     

壳聚糖双胍盐酸盐抑菌活性及其涂膜保鲜圣女果的研究

测定了壳聚糖双胍盐酸盐(CGH)对金黄色葡萄球菌、大肠杆菌和番茄丝核菌的抑菌能力;并通过涂膜的方法处理圣女果,测定贮藏过程中果实失重率、硬度、可溶性固形物含量(TSS)、维生素C(VC)含量、细胞膜透性和总酸含量的变化。结果表明,相对于壳聚糖(CTS),CGH对金黄色葡萄球菌、大肠杆菌具有较强的抑菌能力,其最小抑菌浓度(MIC)分别为0.31mg/mL和0.62mg/mL;当CGH浓度达到2.00mg/mL时对番茄丝核菌菌丝生长抑制率可达到100%。以质量浓度为3%的CGH涂膜处理的圣女果在(28±2)℃存放12d后,失重率仅为7.5%,硬度仍有21.121N/cm2,TSS为7.2%,VC含量为21.70mg/100g FW(鲜重),膜渗透率为27.4%,可滴定酸含量为0.35%。与对照(CK)相比,显著保持了果实的品质。      

防雾膜对低温贮藏樱桃的保鲜效果研究

以\     

甜樱桃呼吸特性及发酵阈值研究

探明不同温度下密封盒内甜樱桃的呼吸特性和发酵阈值。以‘艳阳’樱桃为试材,采用密闭系统法,研究了不同温度（0、5和20℃）条件下,樱桃包装环境内的气体浓度变化和樱桃的呼吸速率,拟合呼吸速率方程,研究樱桃的发酵阈值。结果表明,密封盒内樱桃的米氏模型参数拟合度较高,各方程决定系数（R²）值均在0.96以上。在0、5和20℃环境下,樱桃果实的最大呼吸速率分别为4.50、7.14和24.39 m L CO₂/（kg·h）,最长贮藏时间分别为156、108和24 h,0℃和5℃环境下的发酵阈值比20℃环境低。综上所述,各温度下密封盒内樱桃的米氏模型参数拟合度较高,低温可以有效地抑制果实的呼吸强度,延长贮藏期。      

丁香精油对樱桃番茄保鲜作用的研究

研究了丁香精油对樱桃番茄采后主要致病菌的抑制作用及对其采后品质和生理的影响。结果表明:丁香精油可有效抑制根霉、灰霉的生长,并可诱导樱桃番茄防御性酶POD、PPO及CAT活性的升高;丁香精油处理可降低果实的腐烂指数,120μL/L丁香精油熏蒸对樱桃番茄的防腐保鲜效果最好,贮藏19d后腐烂指数比对照降低了70.6%;20℃下贮藏19d之后,丁香精油处理后樱桃番茄的果实硬度、可溶性固形物含量、颜色及可滴定酸与对照组果实相比均无显著差异。      

Effects of light-emitting diode illumination on the quality of fresh-cut cherry tomatoes during refrigerated storage

The effects of light-emitting diode (LED) illumination on the quality of fresh-cut cherry tomatoes were investigated. Tomatoes were exposed continuously to red, green, blue and white LED light for 7 days and control samples stored in darkness. Results showed that blue light treatment significantly led to more total soluble solids, lycopene concentration and individual phenolic compounds (chlorogenic acid, caffeic acid, rutin) after 7 days of storage. On day-5, green and blue light-treated tomatoes showed relatively higher firmness than samples treated by other lights and the control. At the early stage of storage, blue light could preserve the fresh flavour of tomatoes compared to other treatments. Overall, the blue light was most effective in the quality preservation of fresh-cut cherry tomatoes and could be used as a novel strategy in the preservation of fresh-cut fruits and vegetables during shelf life.     

Effect of pulsed ultrasound treatment compared to continuous mode on microbiological and quality of Mirabelle plum during postharvest storage

The effects of pulsed and continuous ultrasound treatment on microbiological and physiological quality of Mirabelle plum fruit were investigated. Freshly harvested Mirabelle plum was treated with 30‐kHz pulsed and continuous ultrasound at 20 °C for 0, 15, 30, 45 and 60 min and subsequently stored at 4 °C for 10 days. The total count of bacteria, total fungi, decay index, titratable acidity (TA), total soluble solids (TSS), colour, texture, ascorbic acid content and total phenolics was measured. The results showed that pulsed and continuous ultrasonic treatment significantly (P < 0.05) reduced the number of microorganisms and improved the quality of Mirabelle plums during storage. Increasing pretreatment time enhanced the positive effects of pulsed and continuous ultrasound. Also, in terms of the total count of bacteria, total fungi, titratable acidity and total phenolics, the pulsed and continuous ultrasound did not show a significant difference (P < 0.05). However, pulsed ultrasound was better compared to continuous mode in preservation of TSS, colour, texture and ascorbic acid content of the fruit during storage. Our results demonstrated that pulsed ultrasound is an appropriate method for improving safety and maintaining the quality of Mirabelle plum fruit.     

Investigation of UV-A light irradiation on tomato fruit injury during storage

We investigated the effect of UV-A light (wavelength 315 to 400 nm) irradiation during storage on tomato fruit injury. Mature green tomato fruit (cv. House Momotaro) were exposed to UV-A at doses of 0.02, 0.5, and 2 mW x cm(-2) throughout storage at 25 degrees C. The physiological disorders, fruit ripening, superoxide dismutase (SOD) activity, and increases in fruit temperature were evaluated. All UV-A-irradiated and nonirradiated tomatoes developed a full red color at the same time (2 weeks). Irradiated fruit ripened normally, and exposure of tomato fruits to UV-A did not lead to the discoloration of ripe tomato fruit at any dosage. The fruit temperature did not increase in response to various UV-A light doses and exposure times, and none of the UV-irradiated fruits showed physiological disorders (dull skin blemish, pitting). The SOD activity of UV-A-irradiated fruit exposed to the various UV-A doses did not significantly (P = 0.05) differ from that of fruit stored in dark conditions. The SOD results imply that UV-A light might not induce reactive oxygen species in UV-A-irradiated fruit.     

壳聚糖/纳米ZnO涂膜对圣女果的保鲜作用

通过溶液共混制备得到不同纳米ZnO含量的壳聚糖/纳米ZnO涂液,观测了该涂膜的微观结构,并考察了其对圣女果的保鲜性。结果发现:当纳米ZnO含量较低(1%和2%)时,纳米粒子较均匀的分散于壳聚糖膜中。但当纳米ZnO含量增加到3%时,纳米ZnO出现了团聚。保鲜实验发现,纳米ZnO含量为1%的壳聚糖/纳米ZnO涂膜能够最大程度的提高圣女果的感官品质、降低其失重率,并减少其在贮藏过程中Vc及可滴定酸含量的损失。而纳米ZnO含量为2%和3%的壳聚糖/纳米ZnO涂膜的保鲜效果不明显。     

不同品种甜樱桃贮藏保鲜技术研究

本文研究不同品种甜樱桃贮藏保鲜技术，结果表明：不同品种甜樱桃耐藏性顺序为美早＞佳红＞红灯＞菊红。     

Using survival analysis to investigate the effect of UV-C and heat treatment on storage rot of strawberry and sweet cherry

Ultraviolet light and heat treatment are proposed as alternative techniques for the use of chemicals to reduce the development of the spoilage fungi Botrytis cinerea and Monilinia fructigena on strawberry and sweet cherry, respectively, during storage. In order to investigate the effect of both physical techniques on microbial inactivation and on fruit quality, inoculated berries were subjected to different temperatures (40-48 degrees C) and UV-C doses (0.05-1.50 J/cm2). For each condition, 20 berries were used. After the treatment, fungal growth, visual damage (holes, stains) and fruit firmness were evaluated during a period of 10 days. The experimental data were analysed statistically using survival analysis techniques. Fungal growth on strawberries was significantly retarded using UV-C doses of 0.05 J/cm2 and higher. The same treatment had no significant effect when applied to cherries. The highest doses (1.00 and 1.50 J/cm2) had a negative effect on the calyx of the strawberry, causing browning and drying of the leaves. No beneficial effect of a low temperature treatment (40-48 degrees C) on the shelf life of strawberries was observed, but fungal development on cherries was retarded at temperatures of 45 and 48 degrees C. These temperatures caused severe damage on strawberries (soft stains, holes, decreased firmness), but had no influence on the quality of sweet cherries.     

番茄果实采后贮藏的颜色动力学研究

研究了番茄采后成熟过程中果皮颜色的变化规律,建立了多种颜色指标的动力学模型。认为番茄采后成熟过程中色泽角(H0)、色泽比(a/b)、色泽总量(La/b)和a值、明度等颜色参数的动力学变化模型符合一级动力学方程。番茄采后成熟过程中最佳颜色指标是色泽角(H0)。根据实验数据采用数理统计的方法分别确定了各颜色模型的参数：参考变化速率常数(Kref)和反应活化能(Ea)。     

不同气调方式对甜樱桃贮后货架期芳香物质的影响

为明确不同气调方式对甜樱桃贮后货架期芳香物质的影响,以砂蜜豆甜樱桃为试材,运用HSSPME-GC-MS和电子鼻2种技术,对冷库贮藏30 d后的甜樱桃果实进行低温货架[(10±1)℃]期间挥发性物质的检测,并探讨快速气调(FA)、二段仿生气调(SBA)和自发气调(MA)对甜樱桃挥发性成分的影响。结果表明:甜樱桃的挥发性成分主要由醛类和醇类组成,其中己醛、(E)-2-己烯醛和(E)-2-己烯醇是甜樱桃的主要风味物质;在贮后货架0 d时,FA、SBA及MA处理醛类和醇类含量分别为50.38%和40.58%、53.04%和38.57%、61.47%和32.80%,到贮后货架8 d,含量变为48.21%和46.52%、56.30%和37.71%、54.29%和38.76%;整个贮后货架期,FA和MA处理的醛类物质相对含量呈缓慢下降趋势,而SBA处理较为平稳的保持了醛类和醇类物质的含量。电子鼻分析结果显示:主成分分析法(PCA)和线性判别分析法(LDA)可以快速有效地区分不同气调处理的甜樱桃果实;并且利用负荷加载分析法(LA)得出,W1W(硫化氢、萜烯类)、W2S(乙醇)、W5S(氨氧化物)传感器对甜樱桃芳香物质的贡献相对较大,与气质联用分析结果相一致。因此,HS-SPME-GC-MS结合电子鼻技术对不同气调处理甜樱桃贮后货架期的芳香物质判别具有可行性。     

交变电场处理对番茄贮藏效果的影响

以"上合219"番茄为试材,比较了经交变电场(-150~150kV/m)和静电场(-150kV/m)一次性短时(15、30min)预处理后番茄果实的贮藏效果。结果表明,交变电场处理效果好于静电场,能够显著降低番茄失重率和腐烂指数。进一步研究了番茄经交变电场(-150~150kV/m)预处理15min后在贮藏过程中生理指标的变化规律。结果发现,交变电场处理15min能显著抑制番茄果实的转红过程,延缓可滴定酸和番茄红素含量的上升,并且促进了脯氨酸的积累。