Practical and theoretical aspects of determining the sulfite-binding capability of white table wines

Работа посвящена совершенствованию методологических основ оценки сульфитосвязывающей способности сухих белых столовых вин. Предложена и экспериментально подтверждена математическая модель связывания сернистой кислоты компонентами вина. Разработана оригинальная методика оценки сульфитосвязывающей способности белых столовых вин и методология ее применения для технологических расчетов при сульфитации вин. The work is concerned with improving the methodological basis for assessing the sulfite-binding capability of dry white table wines. A mathematical model of binding the sulfurous acid by wine components has been proposed and experimentally confirmed. An original method for assessing the sulfite-binding capability of white table wines and a methodology of its application for technological calculations in the process of wine sulfiting has been developed.

The Mechanisms of Thiosulfate Toxicity against Saccharomyces cerevisiae

Elemental sulfur and sulfite have been used to inhibit the growth of yeasts, but thiosulfate has not been reported to be toxic to yeasts. We observed that thiosulfate was more inhibitory than sulfite to Saccharomyces cerevisiae growing in a common yeast medium. At pH < 4, thiosulfate was a source of elemental sulfur and sulfurous acid, and both were highly toxic to the yeast. At pH 6, thiosulfate directly inhibited the electron transport chain in yeast mitochondria, leading to reductions in oxygen consumption, mitochondrial membrane potential and cellular ATP. Although thiosulfate was converted to sulfite and H2S by the mitochondrial rhodanese Rdl1, its toxicity was not due to H2S as the rdl1-deletion mutant that produced significantly less H2S was more sensitive to thiosulfate than the wild type. Evidence suggests that thiosulfate inhibits cytochrome c oxidase of the electron transport chain in yeast mitochondria. Thus, thiosulfate is a potential agent against yeasts.

Hydrometallurgical Leaching of Copper Flash Furnace Electrostatic Precipitator Dust for the Separation of Copper from Bismuth and Arsenic

Flash furnace electrostatic precipitator dust (FF-ESP dust) is a recycle stream in some primary copper production facilities. This dust contains high amounts of copper. In some cases, the FF-ESP dust contains elevated levels of bismuth and arsenic, both of which cause problems during the electrorefining stages of copper production. Because of this, methods for separation of copper from bismuth and arsenic in FF-ESP dust are necessary. Hydrometallurgical leaching using a number of lixiviants, including sulfuric acid, sulfurous acid, sodium hydroxide, and water, were explored. Pourbaix diagrams of copper, bismuth, and arsenic were used to determine sets of conditions which would thermodynamically separate copper from bismuth and arsenic. The data indicate that water provides the best overall separation between copper and both bismuth and arsenic. Sodium hydroxide provided a separation between copper and arsenic. Sulfurous acid provided a separation between copper and bismuth. Sulfuric acid did not provide any separations between copper and bismuth or copper and arsenic.

Use of Filled Bioplastics in Construction

Polymers and associated composite materials play an increasingly prominent role among structural materials. The relevance of the use of bioplastics as an alternative to synthetic polymers increases year by year. In this regard, the paper describes the production of a ligno-filled polymer material based on polyhydroxyalkanoates to be used in the production of building materials. The studies allowed us to produce the material from wood hydrolyzates. The highest yield of reducing substances in course of pine sawdust hydrolysis with 4% sulfurous acid occurred at 170°C. To obtain a biopolymer in liquid wood hydrolyzate medium, the Cupriavidus necator strain was used, which after 50 hours of cultivation gave a biopolymer yield of up to 15 g/l. The studies of the strength characteristics of the composite based on the obtained bioplastic and dried solid wood hydrolysates allowed us to produce a balanced composition for subsequent use in construction.

Differential Metabolites Markers from Trunking and Stressed NonTrunking Sago Palm (Metroxylon sagu Rottb.)

Background: Sago palm is an important agricultural starch-producing crop in Malaysia. The trunk of sago palm is responsible for the production of the starch reaching maturity for harvesting after ten years. However, there are sago palms that failed to develop its trunk after 17 years being planted. This is known as a stressed “non-trunking” sago palm, which eliminates the economic value of the palms. Objective: The study was initiated to compare the differences in metabolite expression between trunking and non-trunking sago palm and secondly to determine the potential metabolite-makers that are related to differential phenotypes of sago palms. Method: Metabolites were extracted using various solvents and analysed using NMR spectroscopy and GC-MS spectrometry. Data obtained were subjected to principal component analysis. Results: The study determined that differential metabolites expression were detected in the leaf extracts of normal trunking sago palm compared to the non-trunking palms. Metabolite groups which are differently expressed between trunking and non-trunking sago palm are oils and waxes, haloalkanes, sulfite esters, phosphonates, phosphoric acid, thiophene ester, terpenes and tocopherols. GC-MS analysis of Jones & Kinghorn extraction method determined two sets of metabolite markers which explains the differences in metabolites expression of trunking and non-trunking sago palm in ethyl acetate and methanol extract of 89.55% comprising sulfurous ester compounds and 87.04% comprising sulfurous ester, sulfurous acid and cyclohexylmethyl hexyl ester respectively. Conclusion: Two sets of metabolite markers were expressed in the trunking and non-trunking sago palm. These metabolites can potentially be used as markers for identifying normal and stressed plants.

Chemical Biopreservative Effects of Red Seaweed on the Shelf Life of Black Tiger Shrimp (Penaeus monodon)

Hypnea musciformis (HM) and Acanthophora muscoides (AM) red seaweeds were evaluated for their antioxidant properties and efficacy to extend the chemical shelf life of black tiger shrimp (Penaeus monodon) during 14-daystorage. Treated shrimp were soaked in five percent ethanolic solution with 500 µg/mL of AM or HM powder for 30 min. HM had more phenols and flavonoids, increased radical scavenging activity, and greater H2O2 reducing power than AM in vitro. Biochemical quality indicators were significantly higher in the control group, followed by HM- and AM-treated samples during storage. On day 14 of storage, controls contained significantly higher amounts of biogenic amines than HM- or AM-treated samples. The shelf life of chilled stored shrimp increased due to the presence of compounds of butylated hydroxytoluene, sulfurous acid, heptadecane, mono (2-ethylhexyl), and 1,2-propanediol found in AM extract and sulfurous acid and 1,2-propanediol found in HM extract. A control group was soaked in the same ethanolic solution as treated samples without algae powder for 30 min. Each group was kept ice-cold during the soaking period. The results obtained demonstrate the usefulness of two seaweed extracts, Hypnea musciformis and Acanthophora muscoides, combined with ice by decreasing the formation of toxic biogenic amines in shrimp, enhancing its shelf life during ice storage.