Effect of Co γ-irradiation on postharvest quality and selected enzyme activities of Pleurotus nebrodensis

Freshly harvested Pleurotus nebrodensis fruit bodies were exposed to four different doses (0.8-2.0 kGy) of ⁶⁰Co γ-irradiation and various physiological changes associated with postharvest deterioration, as well as the activities of selected enzymes (proteinase, polyphenoloxidase, superoxide dismutase, catalase) thought to play a role in the process of deterioration, were monitored during 22 days of subsequent storage at 4 °C and 65-70% relative humidity. An irradiation dose of 1.2 kGy significantly delayed (by 6-9 days) the onset of fruit body softening, splitting and browning compared with non-irradiated controls and test samples subjected to lower or higher irradiation doses. Irradiation with 1.2 and 1.6 kGy also had a positive effect on other indicators of mushroom tissue senescence, resulting in smaller decreases in soluble protein levels and more protracted increases in proteinase activity. Peak levels of polyphenoloxidase activity, widely recognized as causing postharvest browning of mushroom tissue, were also significantly lower (P < 0.05) in fruit bodies exposed to 1.2 kGy compared with non-irradiated controls. Our data increase our understanding of the effects of γ-irradiation on the biochemical changes associated with postharvest deterioration in P. nebrodensis, and improve the prospects of more targeted strategies for extending the shelf life of both this and other mushrooms.     

Evaluation of Antioxidant Activity,and Nutritional and Chemical Composition of Ficus amplissima Smith Fruit

The present study was evaluated using the following in vitro antioxidant methods: 2,2′-azinobis (3-ethyl-benzothiozoline)-6-sulfonic acid disodium salt, phosphomolybdenum, ferric reducing antioxidant power, metal ion chelating activity, super oxide anion radical scavenging, hydrogen peroxide, and hydroxyl radical. Among these assays, acetone extract showed maximum free radical scavenging activity in 2,2′-azinobis (3-ethyl-benzothiozoline)-6-sulfonic acid disodium salt, phosphomolybdenum, metal ion chelating, superoxide anion, hydrogen peroxide, and hydroxyl radical assays. Moreover, the physiochemical, nutritional, and anti-nutritional parameters were analyzed. Its qualitative and quantitative composition was studied by gas chromatography-mass spectroscopy and out of 27 peaks, 27 compounds were identified. These compounds have the property of antioxidant, antimicrobial, and anti-inflammatory activity.     

Effects of high hydrostatic pressure processing and subsequent storage on phenolic contents and antioxidant activity in fruit and vegetable products

Fresh fruits and vegetables have been reported to possess a variety of bioactivities partly due to their high abundance of phenolics. However, traditional thermal pasteurisation during fruit and vegetable processing typically induces a pronounced loss of phenolic compounds. In contrast, nonthermal pasteurisation techniques, especially high hydrostatic pressure (HHP) processing, are beneficial to the retention of phenolics. In addition to more effectively keeping original freshness, flavour and colour of fruit and vegetable products to the greatest extent, in most cases, HHP processing and subsequent storage more effectively sustain the levels of phenolic compounds and antioxidant activity in fruit and vegetable products compared with thermal pasteurisation. Therefore, HHP processing has a huge potential to preserve fruit and vegetable products rich in phenolic compounds.     

Antioxidant Capacity and Phenolic Content of the Aqueous Extract of Commonly Consumed Cucurbits

The antioxidant capacity of commonly consumed cucurbits vegetable was determined by the DPPH, FRAP, Fe³⁺ reducing power, and hydrogen peroxide scavenging assay. The aqueous extract of Luffa cylindrica showed the highest value of phenolic content and antioxidant capacity based on FRAP, Fe³⁺ reducing power, and hydrogen peroxide scavenging assay. However, Laginaria siceraria extract showed the highest flavonoid and DPPH scavenging activities among all three cucurbits used in this study. Phenolic content in aqueous extracts of Luffa cylindrica and Laginaria siceraria was almost equal. Cucurbita maxima exhibited the lowest phenolic, flavonoid content, and exhibited the lowest power of antioxidant scavenging. The antioxidant capacity of cucurbits was significantly correlated (P < 0.05) with the phenolic content of their extracts. The antioxidant capacity of Luffa cylindrica and Laginaria siceraria have also shown a significant correlation (P < 0.05).     

乙酰水杨酸对番茄果实内各部位糖分含量的影响

采用不同浓度乙酰水杨酸处理番茄果实,对在不同发育阶段果实各部位组织中的糖分含量变化进行了测定,结果表明:在番茄果实不同发育期,果实果皮、胶质胎座和心室隔壁中果糖、葡萄糖和蔗糖含量均表现不同程度的增加,但对果实维管束中糖分含量影响不大,说明乙酰水杨酸具有提高番茄糖分含量的作用。     

猕猴桃加工过程中绿色保持方法的探讨

对野生和栽培猕猴桃品种加工过程中果肉绿色保持方法进行了研究，结果表明，叶绿素的变化和降解与果实中酸度和加工热处理密匹相关，在酸环境以Cu^2 替代mg^2 生成较为稳定的叶绿素铜盐的方法很适合猕猴桃的扩绿，并提出转色的工艺参数。     

吴茱萸花和果实的发育形态学研究

本文报道栽培吴茱萸[Evodia rutaecarpa(Juss.)Benth.]花和果实的发育形态学研究结果雌花的花程式为K_(5)C_5A_5(退化)G(5:5:2)。雌花各部分原基发生顺序是:花萼原基→花瓣原基→雄蕊原基→雌蕊群原基。一般为单性结实,无发育正常的种子。花各部分和果皮均具有油细胞和分泌腔。     

Etude des facteurs d'intensification de l'échange de chaleur dans le refroidissement des fruits et légumesInvestigating the factors for intensifying fruit and vegetable cooling

Increasing the rate of fruit and vegetable cooling is of economic significance for the following reasons: biochemical and microbiological processes are quickly suppressed; surface mass-exchange with ambient air is slowed down; power consumption is reduced, and the freezing output of cooling equipment and installations is increased.It was assumed that the fruits and vegetables in crates were arranged regularly and covered with thin paper of a negligible small thermal resistance in order to eliminate the infiltration of cold air within the layers. Crates were arranged on a pallet so that they touched horizontally. Thus, the packages form plates above and below the cooling air flow. Heat-exchange with a one-dimensional temperature field is established.It was found that intensification of cooling can be achieved by increasing the speed of cooling air as well as by stopping the process at a higher final temperature. Increasing the speed up to 5 m s^?1 shortens the time of the process by a factor of two compared with the low speeds (0.3–0.5 m s^?1) which are normally used. The product can be cooled until the temperature in the layer centre reaches 5°C, and the surface temperature about 2°C, which is low enough. Afterwards the cooled product is transferred to a freezing chamber or to a van-freezer. This factor results in a further halving of the cooling time. The combined effect of the two factors shortens the duration of the process by about 75% and increases the output of the cooling equipment from 3.5 to 4 times.