Effects of packaging materials following ethanol and benomyl treatments on chemical and microbiological changes in tomato (Lycopersicon esculentum) fruits

The effects of various post-harvest treatments on chemical changes, microbiological quality and occurrence of spoilage in ripe tomatoes (Lycopersicon esculentum L) were investigated. Fruits were pretreated in 70% ethanol or 0.2% benomyl before being packaged in low density polyethylene (LDPE), high density polyethylene (HDPE) or raffia palm basket. Fruit was stored at 27–32°C for up to 16 days. Control fruits (without pretreatment or packaging) showed the highest increase in pH; basket-packaged fruits were erratic but LDPE- and HDPE-packaged fruits showed gradual increases. Changes in titratable acidity were the inverse of those in pH. Among packagings, LDPE most effectively maintained total soluble solids (TSS) as compared with basket-packaged fruits, and the control showed the lowest TSS. Of the pretreatments, benomyl-treated fruits retained higher TSS. Aspergillus spp, Penicillium spp, Pseudomonas spp and Escherichia spp occurred most commonly in control and basket-packaged fruits, but Rhizopus spp and Leuconostoc spp predominantly occurred in LDPE- and HDPE-packaged fruits. Microbial load was lowest in benomyl-treated fruits followed by ethanol-treated and control fruits. Spoilage was higher (53.1%) in ethanol-treated than in benomyl-treated (43.8%) fruits.     

Review of flavonoids and other phenolics from fruits of different tomato (Lycopersicon esculentum Mill.) cultivars

BACKGROUND: Tomato, one of the most important vegetables worldwide, contains a range of flavonoids and phenolic acids in addition to lycopene, which are regarded as potentially useful compounds with respect to health benefits. Composition data in fresh tomatoes vary due to genetic and environmental factors and cultural practices. Breeding programs aim to produce tomatoes with enhanced levels of flavonoids and other phenolics. RESULTS: The present paper gives an overview of flavonoids, stilbenoids and other phenolics reported to occur in tomato fruits. Contents are reported for a wide range of cultivars and types. Metabolism of phenolics during fruit maturation and tissue location are described, and an overview of measured contents is given. Effects of environmental conditions and cultural practices are estimated using available literature. Recent literature on transgenic tomatoes is included, and possibilities for regulating phenolic contents in tomatoes are discussed. CONCLUSION: The literature review clearly discloses a rapidly growing interest in flavonoids and other phenolics in tomato fruits and products made thereof. This is particularly connected to the antioxidant properties of these compounds as well as other possible health effects. Choice of cultivar and effects of environment and agronomic practices are important factors with respect to phenolic qualities and quantities of tomatoes. Copyright © 2009 Society of Chemical Industry     

Quality Comparison of Hydroponic Tomatoes (Lycopersicon esculentum) Ripened On and Off Vine

There is a general belief that the quality of tomatoes ripened on vine is better than tomatoes ripened off the vine, influencing among other parameters, the price of this commodity. We compared the quality of hydroponic tomatoes ripened on and off vine by chemical, physical, and sensory evaluation to find what attributes are affected and to what extent. Lycopene, β-carotene, total and soluble solids, moisture content, ascorbic acid, acidity, pH, texture, and color were analyzed. Tomatoes ripened on vine had significantly more lycopene, β-carotene, soluble and total solids, higher a* and lower L*, and were firmer. However, a 100-judge panel rated only the color and overall liking of the vine-ripened tomatoes as more intense than the fruit ripened off vine. Therefore, the chemical and physical differences were mostly not large enough to influence the panelist's perception. The characterization of tomatoes ripened on and off vine may help to guide post-harvest handling and treatment and to improve the quality of tomatoes ripened off vine.     

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。     

Methyl jasmonate coupled with modified atmosphere packaging to extend shelf life of tomato (Lycopersicon esculentum Mill.) during cold storage

The effects of methyl jasmonate coupled with modified atmosphere packaging (MJ+MAP) on the quality and shelf life of mature green tomato ( Lycopersicon esculentum Mill.) were investigated during cold storage at 5 °C. Tomatoes were treated with 10⁻⁴  m MJ and packaged under 5%O₂/5%CO₂/90%N₂ in a plastic bag. The effects of MJ+MAP were compared with control as well as heat treated (HT) samples. Control samples were tomatoes packaged under atmospheric air. HT samples were prepared by dipping tomatoes in hot water at 50 °C for 3 min and packaged under atmospheric air. The results showed that MJ+MAP and HT could delay ethylene production during tomato ripening and consequently slowed down the softening rate. MJ+MAP tomatoes showed better quality and less chilling injury (CI) symptoms than HT and control samples. Based on a nine-point score, shelf life criteria assumed that rejection would occur when the sensory attributes declined below 5. Control and HT overall acceptance scores were shown to fall below 5 scores after 3 and 6 weeks storage, while MJ+MAP had overall acceptance scores above 5 for up to 9 weeks. Control and HT samples could be stored for about 4 and 6 weeks, respectively, while MJ+MAP tomatoes could be stored for up to 9 weeks.     

氯化钙处理对李果实贮藏冷害及营养品质的影响

为探索减轻李果实冷害的新途径,以串红李子为试材,研究了不同浓度的氯化钙处理对低温下贮藏的李果实冷害及营养成分的影响。结果表明,对照果在冷藏12d后,可滴定酸、Vc含量都呈现快速下降的趋势,还原糖、可溶性蛋白、总糖含量异常上升,冷害指数逐渐增加,说明此时冷害已经发生。而经过氯化钙处理的果实,蛋白质、还原糖、总糖含量都呈现上升、下降的趋势,Vc含量呈现缓慢下降的趋势,外观冷害指数明显降低,内部冷害指数只有处理3明显低于对照,说明氯化钙处理从外观上明显地抑制了李果实冷害的发生,而综合内外两种冷害指数来看,只有处理3抑制冷害的效果最好,保持了李果实较好的营养品质。     

不同包装方式对贮藏牛肉食用品质的影响

实验以延边黄牛腿肉为实验对象,采取托盘包装、真空包装和热收缩包装,(4±1)℃冷藏,通过检测蒸煮损失、pH、剪切力、表面颜色,研究不同包装方式对贮藏期间牛肉品质的影响。实验结果表明:贮藏时间和包装方式对延边黄牛肉品质影响显著(p<0.05),真空包装牛肉的pH上升速率较慢,表面颜色的稳定性好,真空包装保鲜效果最好,保质期可达21d,热收缩膜包装的牛肉保鲜效果次之,保质期为18d,而托盘包装的牛肉保质期仅为12d。      

水杨酸处理对梅杏采后贮藏品质的影响

以梅杏为试材,用浓度为0.3、0.5、1.0g/L水杨酸（SA）溶液（清水为对照）浸果实20min后进行冷藏,研究水杨酸处理对梅杏采后贮藏品质的影响。结果表明,0.5g/L水杨酸处理能够较好地降低梅杏的呼吸强度和失重率,抑制细胞膜透性和丙二醛含量的增加,保持较高的硬度、可溶性固形物、可滴定酸、VC含量,减少梅杏腐烂发生,从而延长贮藏期。     

Effect of sea water on biochemical properties of fruit of tomato (Lycopersicon esculentum Mill.) genotypes differing for ethylene production

BACKGROUND: Three near‐isogenic lines of cv. Gimar differing in ethylene production were used to evaluate the influence of salinity on fruit quality. Plants were grown in rockwool culture and were irrigated with nutrient solution with electrical conductivities (ECs) of 3 and 8 mS cm^?1, which corresponded to 0 and 10% of sea water. For fruits picked at ‘red‐turning’ and ‘red‐ripe’ stages physico‐chemical parameters, ethylene, ascorbate and organic acid content, and cell reductive power were analysed. RESULTS: The same response was observed in all genotypes: the higher salinity growth solution increased dry matter content, total soluble solids (TSS) and titratable acidity but reduced crop yield. Ascorbic acid and also organic acid contents showed a greater accumulation with ripening in the mutant genotypes: this might be due to a slowing of ripening. Our data confirm the lack of any relationship between the larger accumulation of TSS and ethylene production in the fruits of salt‐treated plants. CONCLUSION: These findings suggest that although salinity (10% sea water) reduces fruit yield, it does not have a negative effect on quality. So, it seems possible that controlled use of diluted sea water, combined with suitable tomato genotypes might represent a valid alternative to fresh irrigation water. Copyright © 2007 Society of Chemical Industry     

运输过程中振动条件对西红柿贮藏品质影响

根据运输过程中实际情况,实验研究了运输过程中振动频率和振动加速度对西红柿贮藏品质的影响,分别研究了西红柿果实在10、20、30、40、50 Hz五种振动频率以及2.5、5、7.5 m/s23种振动加速度下硬度、可溶性固形物、可滴定酸、维生素C变化。结果表明,在不同的振动条件下,西红柿果实硬度、可滴定酸、维生素C含量均下降,MDA含量上升,内部可溶性物质先上升后下降,但根据其速率及含量变化得出在20 Hz的振动频率、2.5 m/s2的振动加速度下的损伤最小。      

SRE处理对采后番茄贮藏效果的影响

研究乙醇的新型固体缓释剂(slow-release ethanol,SRE)对采后番茄贮藏效果的影响。以番茄‘粉太郎’为试材,破色期采收,在20℃、相对湿度85%的条件下贮藏,用SRE处理,以不做任何处理为对照,测定番茄贮藏期间品质特性、乙烯释放量及多聚半乳糖醛酸酶(polygalacturonase,PG)和纤维素酶活性。结果表明:SRE处理可以提高果实亮度,延缓果实质量损失率降低,减少可溶性固形物含量损失,保持一定硬度,同时提高了果实贮藏后期糖酸比,比对照果实延缓变红6 d。SRE处理显著降低乙烯释放量和PG、纤维素酶活性。综上,SRE处理可以延缓采后番茄果实成熟衰老,从而延长货架期,使番茄更长久保持风味品质。     

不同包装材料对半干青鱼常温贮藏过程中品质的影响

以半干青鱼为研究对象,测定感官评分、水分含量、pH、菌落总数、硫代巴比妥酸(thiobarbituric acid,TBA)值、挥发性盐基氮(total volatile basic nitrogen content,TVB-N)等指标,探究了普通聚乙烯包装和乙烯-乙烯醇共聚物(ethylene-vinyl alcoh...     

The effects of 1-methylcyclopropene treatment on the shelf life and quality of cherry tomato (Lycopersicon esculentum var. cerasiforme) fruit

The use of 1‐methylcyclopropene (1‐MCP) to extend the shelf life of cherry tomato (Lycopersicon esculentum var. cerasiforme) was investigated. Higher concentrations of 1‐MCP delayed the ethylene induced climacteric peaks in mature green (MG) and breaker (BR) fruits. Thirteen days after treatment, control fruits were 55% as firm as fruit treated with 0.11 μL L^?1 1‐MCP. The initiation of fruit softening, chlorophyll degradation and accumulation of lycopene and carotenoids was delayed in treated fruits. Higher 1‐MCP concentrations inhibited the accumulation of lycopene and carotene such that the colour of the fruit did not reach that of control fruit. Treatment of MG cherry tomatoes with 1‐MCP enhanced shelf life optimally, while treatment of BR fruits was beneficial where full colour and high content of lycopene and carotenoids is important. Differentiation of the different stages of ripening before application of 1‐MCP is needed in order to succeed in accomplishing different postharvest objectives.     

不同包装方法下大米储藏品质的变化研究

我国是大米的主要生产和消费大国,但由于经过加工后的大米失去了皮壳的保护层,在储藏期间常因呼吸、氧化和酶的作用而发生若干化学变化,从而导致其品质发生变化。因此,寻求一种利用现代科学技术加强保鲜效果,以延长大米保质期的包装方法迫在眉睫。研究了在自然、充CO2、充N2和抽真空包装方法下大米储藏品质的变化,结果表明,在4种包装方式中,真空包装的品质变化幅度最小,是延缓大米品质变化最好的一种包装方式。     

不同品种番茄对发酵番茄酱品质的影响

为了丰富番茄加工品种,开发一种发酵番茄酱。以四种新鲜的番茄品种为原料,添加凯里红酸汤来制作发酵型番茄酱并跟踪发酵过程中总酸、pH值、亚硝酸盐、番茄红素、可溶性固形物含量变化以及对成品感官评价。结果显示：美宝、奥宝番茄感官评价较好,品种间pH值变化无显著差异（P＞0.05）,美宝总酸含量、亚硝峰峰值最高,发酵结束后美宝总酸比市售番茄酱高出34%。美宝、经典欧卡番茄其与市售番茄酱番茄红素含量相近。美宝可溶性固形物含量最高为42%,各品种可溶性固形物含量均大于市售番茄酱。不同品种番茄酱发酵后成分具有一定的差异,结合不同品种的发酵番茄酱之间的特点,美宝番茄发酵后风味比市售番茄酱更佳。     

充气包装对青菜冷藏品质的影响

充气包装已成为一种有效的延长小包装蔬菜货架期的保鲜技术。目的是选择最合适的环境气调贮藏包装青菜,研究贮藏在4℃,不同的气体浓度(空气对照组、10%CO2+20%O2+70%N2、10%CO2+5%O2+85%N2、10%CO2+1%O2+89%N2、5%CO2+5%O2+90%N2、15%CO2+10%O2+85%N2)对其感官品质、叶绿素、亚硝酸盐、可溶性固形物、电导率等指标的影响。结果表明:4℃下,延长青菜货架期和保持其营养品质的最佳的气体组成为10%CO2+5%O2+85%N2。     

Antimicrobial efficacy of gaseous chlorine dioxide against Salmonella enterica Typhimurium on grape tomato (Lycopersicon esculentum)

The aim of this study was to investigate the effects of gas level and treatment condition on antimicrobial efficacy of ClO₂ gas against Salmonella enterica Typhimurium on grape tomato (Lycopersicon esculentum). Grape tomatoes were dip‐inoculated with inoculum of S. enterica Typhimurium TISTR 292 (ATCC 13311) (9.79 ± 0.39 log CFU mL^?1) and allowed to dry before treatments. The pre‐inoculated samples were exposed to 0.15–0.85 mg of ClO₂ gas, for up to 58 min. The treatments at 4 and 25 °C resulted in population reductions of S. enterica Typhimurium of up to 3.95 ± 0.22 and 7.37 ± 0.39 log CFU per fruit, respectively. The population reduction results were used to construct statistical models to predict efficacy of ClO₂ gas. The second‐order equations for treatments at 4 and 25 °C had R² of 0.87 and 0.95, respectively, and indicated that efficacy of ClO₂ gas was significantly influenced by ClO₂ gas level, exposure time and treatment temperature.     

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)。     

包装处理对阿克苏地区鲜食核桃贮藏品质的影响

为探索南疆新2核桃鲜食果仁最佳的物理保鲜方式及贮藏条件,以果仁的氧化品质变化作为评价指标,采用铝箔包装、充气包装、真空包装方式并以自然裸放作为对照,贮藏于低温(4℃)和室温(25℃)条件下,并测定贮藏过程中核桃仁酸价、过氧化值、皂化价、碘值、丙二醛含量、过氧化氢酶、过氧化物酶、超氧化物歧化酶活性指标的变化,运用方差分析研究不同贮藏条件下各指标变化的差异性。结果表明:核桃仁的酸价、皂化价、过氧化值和SOD酶活性随着贮藏时间的延长,呈现整体上升趋势,而碘值呈下降趋势,MDA值和CAT酶活性变化规律呈现先上升后下降趋势,POD酶活性呈现先下降后上升趋势;随着贮藏时间的延长,核桃仁各评价指标之间存在显著差异性(P0.05),包装处理对核桃品质的评价指标影响差异性显著(P0.05),从而得出新2核桃仁经过真空包装,在低温条件(4℃),可贮藏80d,并能有效维持核桃的鲜食特性。