Differences In Total Acids Research Articles

Influence of the synthesis route on Au-Ir/Al2O3 catalysts performing the total propane oxidation reaction at low temperature

The current study highlights synthesis as a key parameter for obtaining Au-Ir/Al2O3 bimetallic catalysts using the deposition-precipitation with urea (DPU) method. Both co-deposition and sequential deposition (first by adding Au and then Ir and vice versa) were employed. These approaches were compared with the sol-gel and impregnation methods, revealing notable differences in the catalytic oxidation of C3H8 at low temperatures. The Au-Ir/Al2O3 catalysts prepared via co-deposition and sequential deposition demonstrated outstanding results, producing nanoparticles as small as 1 nm when thermally reduced in hydrogen at 400 °C; also, these catalysts exhibited greater capacity for oxidizing C3H8 below 280°C than the Ir/Al2O3 and Au/Al2O3-based catalysts. Characterization of the catalysts was conducted by employing various techniques, including in-situ DRIFTS, UV-Vis, H2-TPR, HAADF-STEM-EDS, XPS and surface acidity determinations by pyridine thermo-desorption. This last technique showed differences in total acidity (Brönsted and Lewis) provoked by the Au-Ir interaction in the different catalysts, which significantly influenced their ability to oxidize C3H8 towards CO2. The results emphasize the effectiveness of the co-deposition and sequential deposition methods using the DPU approach compared to the sol-gel and impregnation methods.

Amino acid and fatty acid compositions of Rusip from fermented Anchovy fish (Stolephorussp)

Rusip is a typical food of Bangka Belitung Indonesia made from fermented anchovy. This study aims to determine the properties of chemistry, microbiology, composition of amino acids and fatty acids from fermented fish spontaneously and non spontaneously. Spontaneous rusip treatment is done by anchovy fish (Stolephorussp) after cleaning and added salt 25% (w/w) and palm sugar 10% (w/w). While, non-spontaneous rusip is done by adding a culture mixture of Streptococcus, Leuconostoc, and Lactobacillus bacteria 2% (w/v). The materials are then incubated for 2 weeks. The data obtained were then performed t-test at the level of 5%. Spontaneous and non-spontaneous rusip fermentation process showed significant differences in total acid, reducing sugar, salt content, TVN, total lactic acid bacteria, total mold, and total microbial. The dominant amino acid content of spontaneous and non-spontaneous rusip are glutamic acid and aspartic acid, while the dominant fatty acids in spontaneous and non-spontaneous rusip are docosahexaenoic acid, palmitic acid, oleic acid, arachidonic acid, stearic acid, eicosapentaenoic acid, palmitoleic acid, and myristic acid.

효모의 종류를 달리하여 제조한 Black Raspberry 발효주의 품질 특성

시판 효모 4가지(Fermivin, FM; Saf-instant yeast red, SI; Angest wine active dry yeast, AW; Angest instant yeast high sugar, AI)를 이용하여 복분자 발효주를 제조하고, 품질 특성을 비교하였다. 환원당 함량은 FM(2.7%)과 AI(2.8%)가 SI(2.4%)와 AW(2.5%)보다 높았으며, 검출된 주요 유리당인 glucose의 함량은 AW와 AI에서 유의적으로 높았다. 알코올 함량은 AW(11.95%)에서 가장 높고, SI(11.75%)에서 가장 낮았다. pH는 FM(pH 3.73)에서 가장 낮았으며, 총 산도는 효모별로 차이가 없었다. 모든 시료에서 검출된 주요 유기산은 citric acid였으며, 효모별로 검출된 유기산 함량은 달랐다. Malic acid의 경우 SI(2.92 mg/mL)에서 가장 많았고 AI(1.83 mg/mL)에서 가장 적었다. L, a, b 값은 SI에서 높고 AI에서 낮았으며, 탁도는 효모에 따라 차이가 없었다. 복분자 발효주의 total phenolics와 total anthocyanin 함량은 효모 별로 차이가 없었으나, 국내에서 판매되는 수입산 레드 와인보다 높았다. 항산화능 역시 효모별로 차이가 없었으나 FM, AI, AW, SI 순으로 높았으며, 항산화능 지표에는 total phenolics와 anthocyanin의 함량뿐만 아니라 anthocyanin 조성도 영향을 미쳤다.

Improving olive oil quality using CO 2 evolved from olive pastes during processing

The effect of blanketing with CO2, naturally evolved during malaxation of olive pastes, on the quality of virgin olive oil was investigated at lab-scale. The O2 depletion was monitored along with CO2 emission to confirm the previously hypothesized accelerated respiration. Malaxation experiments were conducted for 180 min both in sealed (SC) and in the traditional open-to-air conditions to ascertain whether the oil quality was affected by O2 concentration as afforded by CO2 blanketing. The quality of olive oils obtained at different time intervals was monitored by total acidity, peroxide value (PV), specific extinction coefficients K232 and K270, total chlorophyll and total hydrophilic phenols, and HPLC hydrophilic phenols profile. A rapid decrease in oxygen concentration and a simultaneous increase in CO2 concentration were recorded, confirming the accelerated respiration. The oil produced in SC showed a lower PV and K232 coefficient and a higher chlorophyll (10–17 mg/kg) and hydrophilic phenols (110 mg/kg) concentration. No differences in total acidity and K270 coefficient were observed. The hydrophilic phenols profile indicated that, at least for the Frantoio cultivar and an advanced ripeness state, the maximal extraction is generally achieved already after 20 min. Most of the individual hydrophilic phenols have higher concentrations (up to 50%) in SC.

Insecticidal activity and biodegradation of the toxin from bacillus thuringiensis subsp. kurstaki bound to humic acids from soil

The equilibrium adsorption and binding of the active toxin from Bacillus thuringiensis subsp. kurstaki, toxic to lepidopteran larvae, to humic acids extracted from two forest and two cultivated soils, as well as the insecticidal activity and the biodegradation of the bound toxin, were studied. From 75 to 85% of the toxin added was rapidly adsorbed to the humic acids at equilibrium, and adsorption to a constant amount of humic acids increased with the concentration of the toxin until a plateau was reached. Differences in total acidity and in the content of phenolic groups of the humic acids appeared to be primarily responsible for differences in the amounts of toxin bound (45–80% of the adsorbed toxin) after extensive washing with distilled water. The content of carboxyl groups and the degree of polymerization (E4/E6) did not appear to influence significantly the differential binding. Bound humic acid–toxin complexes were toxic to larvae of the tobacco hornworm ( Manduca sexta). The lethal concentration necessary to kill 50% of the larvae (LC 50) of the bound toxin was comparable with that of the free toxin, indicating that the binding of the toxin to humic acids did not affect its insecticidal activity. The bound toxin did not support the growth of a mixed microbial culture from soil, although the free toxin was rapidly utilized as a carbon and energy source for growth, indicating that binding of the toxin to humic acids reduced its biodegradability. The result of these studies indicate that the toxins from B. thuringiensis introduced in transgenic plants and microbes could persist, accumulate, and remain insecticidal in soil as a result of binding to humic acids, as well as on clays, as previously described. This persistence could pose a hazard to non-target organisms and enhance the selection of toxin-resistant target species.

Effects of gamma ray radiation sterilization on chemical components of soy sauce

Soy sauce was treated with γ-ray radiation. The results indicated that there were no significant differences in total acids, total nitrogen, reduced-sugar, sodium chloride and 17 free amino acids between the treated and untreated soy sauce. Specialists from some factories tested the samples and no obvious changes in colour and lustre, flavour, sweet smell and liquid appearance could be identified after the treatment.