不同消毒剂及清洗温度对番茄货架期腐烂率的影响

针对番茄采后腐烂率较高的问题,研究了不同清洗温度〔果温（28±5）℃〕下消毒剂（100  mg·kg^-1 NaClO和5 mg·kg^-1 ClO₂）和自来水清洗处理对番茄货架期（PE包装,室温28～30 ℃,7 d）腐 烂率的影响。结果表明,与不清洗对照相比,清洗后番茄果实腐烂率由47 %下降到9 %～26 %;清洗温度 对自来水和ClO₂处理的番茄果实腐烂率影响不大,但高于果温（28 ℃）5 ℃的NaClO处理的番茄果实腐 烂率较低于果温5 ℃的NaClO处理显著降低,其货架7 d番茄果实腐烂率仅为9 %,是各清洗处理中效果最 好的。     

From waste to resource: mycoremediation of contaminated marine sediments in the SEDITERRA Project

Purpose

Port-dredging activities produce large volumes of contaminated sediments. Dredged sediments are considered a waste by national laws, but recently the desire to consider them a resource has become widespread and remedies for their contamination are being searched to allow their reuse. In this work, we studied, developed, and tested a method for remediate marine-dredged sediments contaminated by heavy metals using native fungi and a microporous membrane, in order to achieve the sediment quality and allow their reuse.

Materials and methods

Activity was carried out on port sediments from Genoa, Leghorn, Pisa, and Cagliari (Italy). Autochthonous fungi were isolated from each sediment and employed in mycoremediation tests. Two plastic boxes were prepared (for each Port) with 5 kg of sediment in each box, employed for metal bioaccumulation using a sterile polyester membrane inoculated with fungi. Membranes were analyzed at 15, 30, and 60 days after inoculums, and sediments were analyzed after 60 days at the end of the experiment to verify metal contamination degree. Recovery efficiency (RE%) and difference recovery efficiency (DRE%) were calculated for each experiment: the first shows the absorption capability of the membrane-fungi consortium; the second evidences only the fungal contribution to the metal absorption. To assess sediment contamination before and after the mycoremediation treatment, we considered chemical levels of reference L1 (the lowest chemical level of reference) and L2 (the highest chemical level of reference), and the evaluation of chemical hazard (HQ) for the chemical contaminants defined by the Italian Ministerial Decree 173/2016.

Results and discussion

Fungi from Genoa sediments increase the membrane absorption of Cu and Zn. Regarding Leghorn results, RE (%) increases and reaches the maximum value after 60 days of treatment for each considered metal. Cr tot, Ni, and Mn appear to be hyper-bioaccumulated. DRE values of Pisa sediments show that Mn is excluded by fungi and it does not bioaccumulate, while other metals and in particular Cd, Cr tot, Zn, and Sb are bioaccumulated. Cagliari DREs show that fungi are not able to bioaccumulate Cr tot, Ni, and Mn and their accumulation is due to the membrane, while As and Cd are bioaccumulated.

Conclusions

Our work evidenced that selected fungi are able to grow on a microporous support and actively reduce metal concentrations in the sediments, achieving their quality. This biomembrane system may represent an important instrument for the remediation of the residual metal contamination of port sediments.

     

Modeling farm-level adoption of deficit irrigation using Positive Mathematical Programming

Irrigated agriculture in the European Union (EU) is currently adapting to new conditions including the principle of the full recovery of water service costs, the reduction of water availability and the increasing variability in the prices of agricultural products. This has fostered an increasing number of economic analyses to investigate farmers’ behaviour by means of mathematical programming techniques including Positive Mathematical Programming (PMP) models.However PMP models generally consider only activities observed in the reference period even if, under new policies and market conditions, farmers can adopt irrigation techniques they have not used previously. In particular, under increasing water costs or decreasing water availability, farmers can introduce Deficit Irrigation (DI) techniques that might not have been profitable earlier.We propose an extension of the PMP approach to include DI techniques not observed in the reference period. These alternative techniques are identified by means of a crop growth model developed by the FAO. We apply our methodology to a Mediterranean area using three sets of simulations involving: increases in water costs, reductions in water availability, and changes in the prices of the products obtained from irrigated crops.Lacking observations of alternative irrigation techniques, our approach captures potential technology adjustments and assesses the impact of changes in water policy and market conditions in a better way.Simulation results show that increasing water costs do not motivate adoption of DI techniques. Rather, farmers are induced to save water by switching from full irrigation to deficit irrigation when water availability is reduced or the prices of irrigated crops are increased.     

Six-week consumption of a wild blueberry powder drink increases bifidobacteria in the human gut

Wild blueberries are a rich source of polyphenols and other compounds that are highly metabolized by the intestinal microbiota and may, at the same time, affect the intestinal environment itself. A repeated-measure, crossover dietary intervention on human volunteers was designed to study the effect of six week consumption of a wild blueberry ( Vaccinium angustifolium ) drink, versus a placebo drink, in modulating the intestinal microbiota. Relative to total eubacteria, Bifidobacterium spp. significantly increased following blueberry treatment (P ≤ 0.05), while Lactobacillus acidophilus increased after both treatments (P ≤ 0.05). No significant differences were observed for Bacteroides spp., Prevotella spp., Enterococcus spp., and Clostridium coccoides . Bifidobacteria, which have been largely proposed to be of benefit for the host, appeared to be selectively favored suggesting an important role for the polyphenols and fiber present in wild blueberries. Results obtained suggest that regular consumption of a wild blueberry drink can positively modulate the composition of the intestinal microbiota.