The concentrations of (E)-2-hexenal (E2H) have obvious correlation with the color change process in tomatoes during ripening. It is proposed that E2H may play a role in regulating the chloroplast degradation. In this study, the exogenous E2H was applied to tomato fruits and plants to create a higher concentration of E2H atmosphere than naturel released. A set of indices in response to E2H were detected. The color change was inhibited. The ethylene pathway and the involved genes were limited. The results of subcellular structure changes, the fatty acid profiles and the malondialdehyde (MDA) content supported that the chloroplast membranes were specifically degraded. The hydroperoxide lyase (HPL) and the lipoxygenase (LOX) pathway was activated to decompose the free fatty acids. In tomato plants at the harvest stage, E2H did not affect the ripe tomatoes, but inhibited the color changes of green tomatoes, accelerated the withering of the leaves and the branches, and made the fruits fall off easier. The chlorophagy was activated and the autophagosomes were observed to decompose the chloroplasts in leaves. In conclusion, E2H accelerated the chloroplast degradation, by which the color changes were regulated.

蒲公英是一种常见的中草药及野生蔬菜,药食兼用,含有多种功能活性物质,具有抑菌、抗氧化、抗肿瘤、抗炎等功效.目前我国蒲公英在食品中的应用研究较少,且基本停留在实验阶段和初级加工阶段,需要进行深加工来提高蒲公英活性物质的利用率.本文综述了蒲公英的功能活性物质、生理特性及在食品等领域的应用,以期为蒲公英功能活性、加工利用的深入研究和应用提供参考.

甜度是衡量冬枣商品价值的关键特征之一,目前冬枣甜度检测多采用具有破坏性的化学分析方法,不能用于商品化分级分选.本项目利用色差仪检测了冬枣的色差,利用DA-Meter检测了叶绿素含量特征,并检测了可溶性固形物含量(SSC).利用Matrix Laboratory(MATLAB)软件,以色差值L、a、b、c、h,DA值为自变量,以SSC为因变量建立了数学模型.结果表明,DA值与冬枣的甜度几乎没有相关性,而色泽与甜度存在较大相关性,且用色差预测冬枣的甜度是可行的.本研究建立了L、a、c、h与SSC之间的线性回归模型,R2为0.747,相对误差率为4.258％,为冬枣甜度的无损预测提供了新的方法,有利于冬枣分拣智能化的发展.

反式-2-己烯醛((E)-2-己烯醛)是由不饱和脂肪酸经脂肪酸氧化酶(LOX)和脂氢过氧化物裂解酶(HPL)途径催化形成的一种C6醛,并在许多植物多部位中都有较高水平的释放.(E)-2-己烯醛不仅对病原菌有良好的抑制效果,还可以直接或间接地抑制昆虫的侵害.(E)-2-己烯醛亦可诱导植物产生抗病性,并可能是信号分子在相邻植株间传导,在植物直接和间接防御系统中发挥重要作用.(E)-2-己烯醛对果蔬采后真菌具有良好的抑菌效果,能提高果蔬中相关防御酶活性,清除体内活性氧自由基并保持果蔬品质.本文就(E)-2-己烯醛的生态生理功能及在果蔬保鲜中的应用进行了归纳,展望了其潜在功能和应用前景,以期对(E)-2-己烯醛的深入研究提供参考.

In 'Crimson Seedless' grapes, the appearance of senescence caused by abnormal dark red color, the loss of crisp taste caused by the decrease in firmness, and the fading of sweetness caused by the decrease in total soluble sugar (TSS) are the main problems affecting its edible qualities after storage. In the mesocarp, burdock fructooligosaccharide (BFO) restricted sucrose export; therefore, more carbohydrates were retained directly leading to higher TSS and sweetness, and cell osmotic pressure and firmness were retained indirectly. In the exocarp, BFO restricted sucrose import; therefore, the signal molecule sucrose was reduced and the senescence-related processes were inhibited. The downregulation of SUC12 and SUC27 by BFO may play an important role in restricting sucrose transportation. The opposing effects exhibited by exogenous sucrose treatments compared to those of BFO further verified these mechanisms. Based on the above mechanisms, sucrose transportation mediates the fresh-keeping effects of BFO in 'Crimson Seedless' grapes.