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Subject: search.filters.subject.Acetic acid

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    Effect of lactic acid bacteria inoculation and urea on fermentation quality and aerobic stability of sugarcane top silage
    (2026-12-01)
    Bureenok, Smerjai
    ;
    Pitiwittayakul, Nittaya
    ;
    Saenmahayak, Benya
    ;
    Sun, Lin
    ;
    Lukkananukool, Achara
    The aim of this study was to investigate the effect of Lactiplantibacillus paraplantarum ST1 and Limosilactobacillus fermentum G3 and their combination with urea on the aerobic stability of sugarcane tops silages. The fermentation profile was not affected by the interaction between urea and lactic acid bacteria (LAB), except for the lactic acid content (P = 0.012). Lactic acid content was higher in LAB silage (P = 0.008). The use of urea resulted in higher levels of pH value, butyric acid, and ammonia-nitrogen compared to LAB. The addition of urea increased the crude protein, and fiber content in silage and decreased the in vitro dry matter digestibility of silage by 7.1% (P < 0.001). In the urea-treated silages, the pH values remained stable, and the yeast counts remained low during five days of air exposure. In contrast, yeast counts increased in the silages without urea treatment, irrespective of the use of LAB. Clostridium sensu stricto 12 was found exclusively in urea-treated silages. The use of LAB additives without urea appears to be advantageous for the fermentation process of sugarcane tops silage. Despite improving the aerobic stability, the addition of urea is not warranted because it results in a poor-quality silage.
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    Determination of antifungal volatile organic compounds of upland rice vinegar and their inhibition effects on Aspergillus flavus in dried chili pepper
    (2022-04-01)
    Pothimon, Ruttipron
    ;
    Krusong, Warawut
    ;
    Daetae, Pawinee
    ;
    Tantratian, Sumate
    ;
    Gullo, Maria
    Determination of volatile organic components (VOC) produced in high acid upland rice vinegar was conducted using GC-MS. Acetic acid and ethyl acetate at 9.11% and 2.69% (v/v), respectively, were major VOC found in the vinegar while the others were isobutyl acetate, isobutyl alcohol, isoamyl acetate, isoamyl alcohol, phenethyl acetate and phenethyl alcohol. Subsequently, vinegar and VOC were tested, in vitro, for their inhibition on conidia germination of 10<sup>3</sup> conidia/mL of Aspergillus flavus. The exposure with 10% (v/v) of vapor-phase vinegar and pure acetic acid completely inhibited the germination of conidia with 30 min exposure, while VOC mixture of 9.11% (v/v) acetic acid, 0.08% (v/v) isoamyl alcohol, 0.45% (v/v) phenethyl alcohol and 0.01% (v/v) isobutyl alcohol with 45 min exposure could achieve the same target. Then, vinegar vapor was tested on the inhibition of conidia germination and aflatoxin production of A. flavus during 90 d subsequent storage of dried chili pepper. Complete inhibition of conidia germination and aflatoxin production were achieved with the 40 min exposure of 1.04 ± 0.03 mmol/L of vaporized vinegar. Our results showed that fumigation of upland rice vinegar containing antifungal VOC is a simple and an economical method for commercial preservation of dried chili pepper. Upland rice vinegar is a novel bio-fumigant for prevention of mycotoxin production in dried food and feed products during storage.
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    Postharvest control of anthracnose in mangoes by fumigation with vinegar and ethanol vapours
    (2019-01-01)
    Suwapanich, Rachit
    ;
    Krusong, Warawut
    ;
    Thompson, Anthony Keith
    Anthracnose disease of mangoes is caused by Collectotrichum gloeosporioides. A control method that does not include synthetic fungicides would be beneficial therefore fumigation, in an especially designed vapour exposure box, with vapour from upland rice vinegar and ethanol were tested in vitro on C. gloeosporioides isolated from mangoes and cultured on PDA. Fumigation times were 0, 5, 6, 7, 8, 9 or 10 min for ethanol and vinegar vapours separately and in mixtures at different ratios for 0, 10, 11, 12, 13, 14 or 15 min. Exposure to either ethanol vapour or vinegar vapour controlled both mycelial growth and conidia germination during subsequent storage for seven days at 28°C–32°C, but ethanol was more effective than vinegar and ethanol was more effective alone than in any of the combinations with vinegar. These results provide a successful organic anthracnose control method, but in vivo testing is recommended before commercial application
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    Ammoximation of cyclohexanone in acetic acid using titanium silicalite-1 catalyst: Activity and reaction pathway
    (2005-07-18)
    Sooknoi, Tawan
    ;
    Chitranuwatkul, Veerachai
    The activity of titanium silicalite (TS-1) and the reaction pathway for the ammoximation of cyclohexanone to produce cyclohexanone oxime were studied using acetic acid as a solvent at 60 °C. The effect of solvent, sources of nitrogen, water content and the active site stability were also evaluated. It was found that, in the reaction using acetic acid as a solvent, the ammoximation of cyclohexanone proceeded mainly via the oxidation of imine, which was primarily formed in situ by the condensation of ketone with ammonia. In addition, the ammonium salts of weak acids, such as acetate, citrate and carbonate, can be used as nitrogen sources for the ammoximation in acetic acid. Water was shown to inhibit the formation of imine, and also prevent the side reactions. Moreover, TS-1 possessed an excellent stability, and can be reused without significant loss of activity. © 2005 Elsevier B.V. All rights reserved.
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    Activity enhancement by acetic acid in cyclohexane oxidation using Ti-containing zeolite catalyst
    (2002-07-10)
    Sooknoi, Tawan
    ;
    Limtrakul, Jumras
    Titanium silicalite (TS-1) was hydrothermally crystallised from a titanosilicate gel. The solid material was characterised by XRD, IR, and SEM, and then used as a catalyst in the liquid phase oxidation of cyclohexane with hydrogen peroxide. The reaction was carried out for 6 h, at the temperature between 40 and 80 °C. It was found that a marked increase in the catalytic activity was observed in the reaction using acetic acid as the solvent, as compared to those using no solvent and methyl ethyl ketone. Further investigation was made on the cause of activity enhancement, and it was shown that acetic acid was readily oxidised to peracetic acid. This compound was believed to facilitate the complexation of the framework titanium active sites, and subsequently serve as a better oxidising agent, as compared to the original hydrogen peroxide. However, leaching of the titanium species was also observed in small amounts, from the reaction using acetic acid as the solvent. In the mechanistic point of view, there was an evidence suggesting that cyclohexanol might be a primary product from the cyclohexane oxidation, and can be consecutively re-oxidised to form cyclohexanone. It is noted that the direct oxidation from cyclohexane to cyclohexanone cannot be excluded. © 2002 Elsevier Science B.V. All rights reserved.