Fractionation of tomato fruit chromoplasts

Chromoplast differentiation involves an active synthesis of carotenoids associated with the remodeling of the preexisting plastid membrane systems to form specialized structures involved in the sequestration and storage of the synthesized carotenoids. These subplastidial structures show remarkable morphological differences and seem to be adapted to the accumulation of particular carotenoids in some plant species and organs. At present, very little is known about chromoplast biogenesis and the role of the different suborganellar structures in the synthesis and storage of carotenoids. The combination of classical fractionation methods with the use of biochemical and -omics techniques represents an attractive approach to unravel novel aspects related with the biochemical and cellular mechanisms underlying the biogenesis of the structures involved in the biosynthesis and storage of carotenoids during chromoplast differentiation. Here we describe a combined protocol for the isolation, lysis and fractionation of tomato fruit chromoplast. The fractions obtained are suitable for metabolomics and proteomics analysis.We acknowledge the financial support of AGAUR-Generalitat de Catalunya (Grant 2017 SGR 710), the CERCA Programme of the Generalitat de Catalunya and the Severo Ochoa Programme for Centres of Excellence in R&D 2016–2019 to CRAG (SEV-2015-0533). AB is member of the Spanish Carotenoid Network (CaRed) funded by the Spanish Ministry of Economy and Competitiveness (Grants BIO2015-71703-REDT and BIO2017-90877-REDT).Peer reviewe

Aceitabilidade de flocos desidratados de abóbora Dehydrated pumpkin flakes acceptability

OBJETIVO: Avaliar a aceitabilidade de flocos desidratados de abóbora, uma vez que tal produto pode constituir uma alternativa no combate à hipovitaminose A. MÉTODOS: Os flocos foram avaliados quanto às características microbiológicas, por meio das análises de coliformes a 45ºC, Escherichia coli, Staphylococcus aureus, Salmonela sp, contagem de bolores e leveduras, e características físico-químicas, por meio da análise de umidade, proteínas, lipídios, cinzas, fibra alimentar, carboidratos, carotenóides, estabilidade ao longo do tempo de armazenamento e aceitabilidade dos flocos adicionados ao feijão e ao pirão de 188 adultos e 67 crianças, respectivamente. RESULTADOS: Os flocos estavam adequados quanto às características microbiológicas e físico-químicas e os percentuais de aceitação de 95,21% para os adultos e 95,52% para as crianças. CONCLUSÃO: Os flocos desidratados de abóbora podem ser utilizados em larga escala para o estudo do efeito deste produto no combate à hipovitaminose A.<br>OBJECTIVE: The objective of this study was to evaluate the acceptability of flakes since this product can be an alternative in the fight against hypovitaminosis A. METHODS: The flakes were evaluated through analyses of coliforms at 45ºC, Escherichia coli, Staphylococcus aureus, Salmonela sp; counting of yeasts and molds; analysis of moisture, proteins, lipids, ash, dietary fibers, carbohydrates and carotenoids; storage stability; and acceptability of flakes added to beans and "pirão" (a widely consumed Brazilian dish consisting of meat and vegetable broth and cassava flour) by 188 adults and 67 children. RESULTS: The microbiological and physical-chemical characteristics of the flakes were adequate and the acceptability percentages were 95.21% for adults and 95.52% for children. CONCLUSION: Dehydrated pumpkin flakes can be used in large scale to determine its effectiveness in the fight against hypovitaminosis A

Insight into β-Carotene thermal degradation in oils with multiresponse modeling

The aim of this study was to gain further insight into b-carotene thermal degradation in oils. Multiresponse modeling was applied to experimental highperformance liquid chromatography–diode array detection (HPLC–DAD) data (trans-, 13-cis-, and 9-cis-b-carotene concentrations) during the heat treatments (120–180 C) of two b-carotene-enriched oils, i.e., palm olein and copra. The test of different reaction schemes showed that b-carotene isomerization reactions were dominant and reversible. The resulting cis isomers and trans-b-carotene simultaneously underwent oxidation and cleavage reactions at the same rate constant. From the kinetic analysis, it appeared that—contrary to oxidation and cleavage reactions—isomerization rate constants did not follow the Arrhenius law. However, the isomerization equilibrium constant increased with temperature, favoring isomer production, particularly 9-cis-b-carotene. Its production was shown to be concomitant with oxidation and cleavage reactions, indicating that 9-cis-b-carotene could be a good degradation indicator during oil storage or processing

Established and proposed roles of xanthine oxidoreductase in oxidative and reductive pathways in plants

Xanthine oxidoreductase (XOR) is among the most-intensively studied enzymes known to participate in the consumption of oxygen in cells. However, it attracted the attention of researchers due its participation in free radical production in vivo, mainly through the production of superoxide radicals. In plants, XOR is a key enzyme in purine degradation where it catalyzes the oxidation of hypoxanthine to xanthine and of xanthine to uric acid. Both reactions are accompanied by electron transfer to either NAD+ with simultaneous formation of NADH or to molecular oxygen, which results in formation of superoxides. Characterization of plant XOR mutants and isolated XOR proteins from various plant species provided evidence that the enzyme plays significant roles in plant growth, leaf senescence, fruit size, synthesis of nitrogen storage compounds, and plant-pathogen interactions. Moreover, the ability of XOR to carry out redox reactions as NADH oxidase and to produce reactive oxygen species and nitric oxide, together with a possible complementary role in abscisic acid synthesis have raised further attention on the importance of this enzyme. Based on these established and proposed functions, XOR is discussed as regulator of different processes of interest in plant biology and agriculture.The authors acknowledge the support of the research grants AGL2010-16167 to J.F.M. from the Spanish Ministry of Science and Innovation and Bi 1075/5-1 to F.B. by the Deutsche Forschungsgemeinschaft. R.E. received a JAE-Doctor grant from the Spanish Research Council (CSIC).