High Concentrations Of Acetic Acid Research Articles

Extension of growth/no growth predictive models for the preservation of low-acid pasteurized sauces by incorporating water activity and model validation in sauces

Combined preservation methods have awakened a growing interest in low-acid pasteurized sauces under ambient storage, aiming to produce more ‘natural’ foods with enhanced microbial stability. However, limited information and predictive models are available to assess the microbial stability of this kind of products, for which the spoilage is mainly caused by acid-tolerant spore-forming spoilage bacteria (ATSSB). In this study, a set of growth/no growth (G/NG) models developed previously (Sun et al., 2021a) for spores of two ATSSB strains (Bacillus velezensis and Bacillus subtilis) from pasteurized sauces were upgraded to incorporate the effect of water activity (aw). The growth from heat-treated spores (80 °C, 10 min) was assessed during three months in Nutrient Broth under 320 combinations of storage temperatures (22 and 30 °C), aw (0.95 and 0.965), pH (4.4–5.6), total acetic acid (0.0–0.3 % (w/w)), and total lactic acid (0.00–1.00 % (w/w)). Twelve replicates were tested for each combination. After merging the dataset collected previously at aw 0.98, a set of 4-variate (4V) models were developed for each strain under a single temperature after 30, 60 and 90 days separately. Additionally, the developed models were validated by challenge tests in different industrially produced low-acid pasteurized sauces for three months.The results showed that lowering aw significantly enhanced the antimicrobial effect of decreased pH and the addition of acetic and lactic acid against the ATSSB spores, while the enhancement was less evident at high acetic acid concentrations. In the challenge tests, the developed models exhibited accurate predictions for the sauces, with the % correct-predicted values ≥90 %. The developed models can be used in microbiological risk assessments or the innovation of preservation strategies for low-acid pasteurized sauces.

Selection of Debaryomyces hansenii isolates as starters in meat products based on phenotypic virulence factors, tolerance to abiotic stress conditions and aroma generation.

Debaryomyces hansenii is a yeast widely used in meat fermentations as starter for the purpose of improving the aromatic quality of the final product. However, it has not been the subject of an extensive study regarding phenotypic characteristics important for starter selection, such as the capacity to grow at abiotic stress conditions occurring during fermentation, the ability to generate desirable aromas and the absence of virulence traits in yeasts. The aim of this study was to screen 60 strains of D. hansenii isolated from assorted foods for their potential application as starters in dry-cured fermented sausages manufacture. The abiotic stress factors tested were low aw and pH and high concentration of salt, acetic acid and lactic acid. The phenotypic virulence traits explored were growth at 37°C, pseudohyphal and biofilm generation, invasiveness and enzymatic activities present in virulent yeasts. The generation of desirable meat aromas was tested in models containing aroma precursors applying an olfactory analysis. A quantitative profiling of stress tolerance was used to test the potential performance of selected strains in meat fermentations. The results demonstrated that most strains displayed no virulence trait or were only positive for biofilm production. Moreover, the strains showed large heterogeneity regarding their tolerance to abiotic stress factors, although most of them could grow at intermediate to high levels of the traits. The sensory analysis was the criteria determining the selection of starter strains. The evaluation of the phenotypic traits demonstrates that D. hansenii is a safe yeast, it is able to tolerate the stress in meat fermentation and it is able to generate desirable aromas. The results of this study confirm the adequacy of selected D. hansenii strains to be applied as starters in meat products.

Oxidised plasma-sprayed transition metal – Reusable supported catalysts for organic waste treatment

Transition metals were plasma-sprayed onto stainless-steel substrates and further oxidised to form a surface layer of the metal oxides. Catalytic wet oxidation of glucose, a model compound for organic waste was carried out at temperature range of 150–170 °C for 60 min. Rietveld patterns showed evidence of metal oxides in the oxidised coatings of MoO3, Co3O4, CuO and CuNiIn oxide. The SEM cross-sections reveal two-layered coatings for MoO3, Co3O4 and CuO. Highest COD reduction was obtained by Co3O4 after 60 min at 160 °C for the low-oxygen screening trials. Initial screening trials detected a high concentration of metallic Mo, Co and Cu by ICP-MS. The re-oxidised MoO3 catalysts yielded the highest concentration of acetic acid (96 mg L−1) post 60 min of CWO reaction at 170 °C using 40 bar O2. The leaching of Mo metal with spallation of the top oxide layer was confirmed with the reuse trials. On contrary, CuNiIn oxide showed minimum amounts of leached Cu, Ni, and In metals into the reaction media, with the catalyst producing 67 mg L−1 of acetic acid at 170 °C using 40 bar O2. Therefore, CuNiIn oxide was selected as the best oxidised transition metal catalyst for CWO of glucose.

반응표면분석법을 이용한 초산침지처리 태극삼의 진세노사이드 성분과 함량 모니터링

The study aimed to use response surface methodology (RSM) to monitor changes in the composition and contents of ginsenosides as a result of soaking fresh ginseng in an acetic acid solution during the manufacturing process of taegeuk ginseng, resulting in investigating the dynamic changes in protopanaxadiol and protopanaxatriol ginsenosides. The R2 of ginsenoside Rb1, Rb2, Re, Rf, Rg1, and total model formulas were 0.8420 (p<0.1), 0.8422 (p<0.1), 0.9183 (p<0.05), 0.9237 (p<0.05), 0.9007 (p<0.05), and 0.9236 (p<0.05), respectively. Prolonged soaking of protopanaxadiol ginsenoside Rb1, Rb2, Rb3, and Rc in high acetic acid concentrations released all sugars from the OH at position 20 of aglycone, resulting in relatively large amount of Rg3 being formed. Under similar conditions, protopanaxatriol ginsenoside Re and Rf were also converted to Rg1, Rg2, and Rh1 due to sugars released from OH at positions 6 and 20 of aglycone. Rg2 increased on conversion from Re; however, at high acetic acid concentrations, it was immediately converted to Rh1, resulting in a relative decrease. The total ginsenoside contents decreased with increase in the acetic acid solution soaking time. Thus, RSM confirmed that specific ginsenosides were reduced and other ginsenosides formed during the manufacturing process of taegeuk ginseng.

Separating the chemical and microbial factors of oat harvested at two growth stages to determine the main factor on silage fermentation.

This work evaluated the effects of epiphytic microbiota and chemical components on fermentation quality and microbial community of ensiled oat. Oat harvested at the heading stage (HS) and the milk stage (MS) was sterilized by gamma-ray irradiation and inoculated as the following: (1) HS epiphytic microbiota + sterilized HS (H-H); (2) MS epiphytic microbiota + sterilized HS (M-H); (3) MS epiphytic microbiota + sterilized MS (M-M); and (4) HS epiphytic microbiota + sterilized MS (H-M). After 60-day fermentation, silages inoculated with the epiphytic microbiota of HS had higher acetic acid content than those inoculated with MS. Silage made from sterilized MS had lower pH, ammonia nitrogen and butyric acid contents and higher dry matter, water-soluble carbohydrates and lactic acid contents than that made from sterilized HS. The microbial communities of oat silages were similar, and they were mainly Lactobacillus. The chemical component rather than the epiphytic microbiota at harvest exerted more effects on oat silages. This work reveals the different effects of chemical and microbial factors on the fermentation of silage, which is instructive for us to produce quality silage.

Fermentation of Dairy-Relevant Sugars by Saccharomyces, Kluyveromyces, and Brettanomyces: An Exploratory Study with Implications for the Utilization of Acid Whey, Part II

In Greek-style yogurt production, every kilogram of product yields 2 to 3 kg of acid whey (YAW); this coproduct’s composition and low pH pose challenges for its proper valorization and reinsertion into the food supply chain. However, 240 mL of YAW contains over 9 g of lactose and represents a good source of minerals; these traits can be leveraged to develop nutritious fermented beverages. The purpose of this study is to investigate the aerobic fermentation of dairy sugars by different yeasts by characterizing these processes and their products. This will determine whether such methods provide viable options for the production of acetic-acid-containing beverages from YAW. To achieve this, yeast nitrogen base was used to prepare four growth media formulations, each supplemented with lactose, glucose, galactose, or a 1:1 mix of glucose and galactose (GLU:GAL), and each adjusted to a pH of 4.20. Fermentations were performed by pure cultures of S. cerevisiae, K. marxianus, B. claussenii, or B. bruxellensis, and were held at 25 °C with agitation at 185 rpm. For each treatment, density, pH, and microbial enumeration were measured over time to obtain process profiles, while ethanol, organic acids, and sugars were analyzed at the beginning and the end of each fermentation via HPLC, to determine resulting products. ANOVA and Tukey’s honest significant difference test at a significance level of 0.05 were used to compare residual sugars and fermentation products. Variable rates of sugar consumption were observed for each species. In GLU:GAL, B. claussenii consumed all of the glucose, left behind most of the galactose, and produced a high concentration of acetic acid. These results suggest the potential to develop versatile processes that target glucose for acetic acid production, while leaving available galactose to confer products with prebiotic properties. The development of processes for the conversion of YAW into beverages with organic acids and other healthful components not only aligns with consumers’ demands for better-for-you products, but also promotes the valorization of this otherwise underutilized dairy coproduct.

Mutations in degP and spoT Genes Mediate Response to Fermentation Stress in Thermally Adapted Strains of Acetic Acid Bacterium Komagataeibacter medellinensis NBRC 3288.

An acetic acid bacterium, Komagataeibacter medellinensis NBRC 3288, was adapted to higher growth temperatures through an experimental evolution approach in acetic acid fermentation conditions, in which the cells grew under high concentrations of ethanol and acetic acid. The thermally adapted strains were shown to exhibit significantly increased growth and fermentation ability, compared to the wild strain, at higher temperatures. Although the wild cells were largely elongated and exhibited a rough cell surface, the adapted strains repressed the elongation and exhibited a smaller cell size and a smoother cell surface than the wild strain. Among the adapted strains, the ITO-1 strain isolated during the initial rounds of adaptation was shown to have three indel mutations in the genes gyrB, degP, and spoT. Among these, two dispensable genes, degP and spoT, were further examined in this study. Rough cell surface morphology related to degP mutation suggested that membrane vesicle-like structures were increased on the cell surface of the wild-type strain but repressed in the ITO-1 strain under high-temperature acetic acid fermentation conditions. The ΔdegP strain could not grow at higher temperatures and accumulated a large amount of membrane vesicles in the culture supernatant when grown even at 30°C, suggesting that the degP mutation is involved in cell surface stability. As the spoT gene of ITO-1 lost a 3′-end of 424 bp, which includes one (Act-4) of the possible two regulatory domains (TGS and Act-4), two spoT mutant strains were created: one (ΔTGSAct) with a drug cassette in between the 5′-half catalytic domain and 3′-half regulatory domains of the gene, and the other (ΔAct-4) in between TGS and Act-4 domains of the regulatory domain. These spoT mutants exhibited different growth responses; ΔTGSAct grew better in both the fermentation and non-fermentation conditions, whereas ΔAct-4 did only under fermentation conditions, such as ITO-1 at higher temperatures. We suggest that cell elongation and/or cell size are largely related to these spoT mutations, which may be involved in fermentation stress and thermotolerance.

Re-ensiling and microbial inoculant use effects on the quality of maize silages exposed to air

Re-ensiling has increased worldwide due to the increase in marketing of silage between farms. However, litlle is known about the aerobic deterioration and microbial inoculants effect in this process. The aim of this study was to determine the re-ensiling and microbial inoculant use effects on the maize silage quality. Experimental treatments included maize silage exposed to air for zero or 18 h, with or without microbial inoculant use containing a mixture of Lactobacillus plantarum and Propionibacterium acidipropionici. The forage was ensiled in 20 plastic buckets (20 liters capacity) with five repetitions per treatment. The silos were opened after 116 days and the chemical composition, in vitro dry matter digestibility (IVDMD), fermentative parameters, microorganism counts, total dry matter (DM) losses and aerobic stability of silage were evaluated. Re-ensiling reduced the non-fibrous carbohydrates content by 14.8%, whereas it increased the neutral detergent fiber content by 6%. The IVDMD was reduced by 6.1% in re-ensiled silages. In addition, re-ensiling increased the losses due to gases, effluents, and total DM. Lower lactic acid content and higher acetic acid content in re-ensiled maize silages were also observed. However, IVDMD increased by 4.6% in inoculated silages. Re-ensiling reduced the nutritive value and IVDMD of maize silages and should be avoided in production systems. The microbial inoculant use was not effective in improving the re-ensiled silage quality, which does not justify its use in these conditions. Farms should avoid purchasing maize silage due to reduction in nutritional value in the re-ensiling process. However, in some cases where farms need to purchase silage for feeding planning, the time between silo opening and re-ensiling should be as short as possible to reduce nutrient loss. Furthermore, in this situation the inoculant use does not improve silage conservation, which makes its use unnecessary.

Experimental and molecular dynamics simulation of organic structure of bituminous coal in response to acetic acid

To investigate the effect of acetic acid on the organic structure of coal, experimental studies and molecular dynamics simulations were used to jointly characterize the response mechanism of the organic structure of coal to acetic acid. The functional groups of coal after the dissolution of different concentrations of acetic acid were tested using Fourier infrared spectroscopy, and the results showed that: the sensitivity of functional groups in coal to different concentrations of acetic acid differs, and acetic acid mainly acts to break the linkage bonds between molecules and hydroxyl groups, producing a large amount of –OH; high concentrations (100% and 75%) of acetic acid react with CH2 alkanes to produce new CH2 alkanes, but low concentrations (50% and 25%) acetic acid does not undergo this reaction. In this paper, we model the solid–liquid system of coal-acetic acid reaction, simulate and characterize the reaction of bituminous coal organic structure to acetic acid, and find that: water molecules can help acetic acid molecules adsorb on the surface of coal molecules, but water molecules will occupy a large amount of space, thus affecting the adsorption of coal molecules. Most of the coal molecules have water molecules and acetic acid molecules adsorbed on the benzene ring and oxygen-containing functional group structures, while the functional groups associated with aliphatic groups in coal molecules are difficult to adsorb due to their hydrophobicity.

Crystalline silicon photovoltaic module degradation: Galvanic corrosion and its solution

Corrosion is a significant cause of degradation of silicon photovoltaic modules. In this study, the corrosion of multicrystalline passivated emitter and rear cells (PERC) was investigated using both experimental and numerical approaches to identify high-corrosion locations and their effect on cell parameters. Corrosion environments were simulated by immersing the device in acetic acid solution at various dwell times. The impact of the acetic acid concentration and relative humidity was examined. Thermodynamic and kinetic analyses of corrosion were performed using a Pourbaix diagram and finite element analysis, respectively. The results indicate that the device power reduces slowly in pure water but is faster in acidic environments at dwell times below 96 h. The power loss was over 60% in all environments at a dwell time of 144 h. In particular, a rapid power loss over 40% was observed at a high acetic acid concentration of 20 wt% after a dwell time of merely 48 h. The power loss in the water environment can essentially occur due to the formation of a surficial metal oxide layer, while in an acidic environment, it may be due to corrosion and/or metal electrode dissolution. The simulation and experimental results demonstrate that the rear aluminum around the silver contact suffers crucially from corrosion; thus, it is the main cause of device power losses. A polymer (EPDM) efficiently prevents water penetration into the electrode areas, thus minimizing power loss due to corrosion, and effectively solves the problem without impacting the production cost.

Trickle-Bed Bioreactors for Acetogenic H2/CO2 Conversion

Acetic acid is an essential industrial building block and can be produced by acetogenic bacteria from molecular hydrogen (H2) and carbon dioxide (CO2). When gasses are supplied as substrates, bioreactor design plays an important role for their availability. Trickle-bed bioreactors (TBs) have an enhanced gas-to-liquid mass transfer and cells remain in the system by forming a biofilm on the carriers. So far, TBs have been investigated extensively for bio-methanation processes, whereas studies for their use in acetic acid production are rare. In this study, we evaluated the reproducibility of two parallel TBs for acetic acid production from H2:CO2(= 70:30) by a mixed culture with a gas flow rate of 3.8 mL min−1and a medium flow rate of 10 mL min−1. Additionally, the effect of glucose addition during the starting phase on the resulting products and microbial composition was investigated by setting up a third TB2. Partial medium exchanges to decrease the internal acetic acid concentration (AAC) combined with recycling of withdrawn cells had a positive impact on acetic acid production rates with maxima of around 1 g L−1d−1even at high AACs of 19–25 g L−1. Initial glucose addition resulted in the accumulation of unwanted butyric acid up to concentrations of 2.60 ± 0.64 g L−1. The maximum AAC of 40.84 g L−1was obtained without initial glucose addition. The main families identified in the acetogenic TBs were Peptococcaceae, Ruminococcaceae, Planococcaceae, Enterobacteriaceae, Clostridiaceae, Lachnospiraceae, Dysgonomonadaceae and Tannerellaceae. We conclude that a TB is a viable solution for conversion of H2/CO2to acetate using an anaerobic enrichment culture.

Electro-digestion of food waste and chemically enhanced primary treated sludge

The aim is to develop an optimized electro-digestion (ED) process for production of organic acids from food waste (FW) and chemically enhanced primary treated sludge (CEPT) under 10% semi-solid conditions. The FW (100 g) and CEPT sludge (1000 mL) were mixed under pre-optimized conditions (1:10 ratio) in a four identical stirred tank reactors (CSTRs) operated as ED system (i.e., 0.3, 0.6 and 0.9 V) at room temperature for 20 days at 150 rpm. By adding alkali, pH was maintained near neutral and the samples were collected intermittently for physio-chemical and bacterial community analysis. From the results, ED under 0.3 V favored 60% higher organic acid production over control. The ED system enriched with distinct bacterial diversity such as Bifidobacterium, Anaerofilum and Paracoccus whereas the control enriched with Pseudomonas, Eneterococcus and Tepidomicrobium. To conclude, the ED of FW with CEPT sludge under semi-solid conditions is recommended to produce high concentrations of acetic acid.

Ethanolic Stem Bark Extract of Boswellia dalzielli H Promotes the Healing of Acetic Acid Induced Chronic Gastric Ulcer by Down-Regulation of Tumor Necrosis Factor (TNF) -Αlpha in Wistar Albino Rats

The present study determines the effects of the ethanolic stem bark extract of Boswellia dalzielii H on gastric homogenate and serum levels of TNF-α and vascular endothelial growth factor (VEGF), during the healing of chronic gastric ulcer induced by acetic acid in Wistar albino rats. Round and deep chronic gastric ulcers were induced by a high concentration of acetic acid in Wistar albino rats. 75 rats with gastric ulcers were randomly assigned to five treatment groups (2-5). Rats in group 1 had no gastric ulcer and were administered with vehicle 5ml/kg. Rats in group 2, negative control had gastric ulcers and were treated with vehicle 5ml/kg. Rats in group 3 were treated with ranitidine (50mg/kg) while rats in groups 4, 5, and 6 were treated daily with 100, 200, and 400mg/kg of ethanolic stem bark extract of Boswellia dalzielli H respectively. Treatment in all the groups was by intragastric administration. Five rats from groups (2-6) were euthanized on days 3, 7, and 9 along with the control group (1). Blood was collected, serum prepared, and assayed for TNFα and VEGF using ELISA. The stomach of each animal was evaluated for gastric ulcer, assessed for histopathologic changes, and preparation of gastric tissue homogenates. Intragastric administration of graded doses of ethanolic stem bark extract of Boswellia dalzielli H and ranitidine (50mg/kg) respectively, down-regulated serum and gastric tissue levels of TNF–α significantly (p<0.05), up-regulated VEGF significantly (p<0.05), and increased gastric ulcer healing rate in a significant manner (p<0.05). The increase was time and Dose and time dependent manner when compared to control. Attenuation of TNFα and up-regulation of VEGF by graded intragastric administration of the ethanolic stem bark extract of Boswellia dalzielli promotes the healing of chronic gastric ulcer induced by acetic acid in Wister albino rats.

Exploring the Addition of Herbal Residues on Fermentation Quality, Bacterial Communities, and Ruminal Greenhouse Gas Emissions of Paper Mulberry Silage

This study aimed to investigate the influence of herbal residues on the fermentation quality and ruminal fermentation of paper mulberry silage. Clove, mint, and purple perilla residues were used as additives. Silage treatments were designed as control (no additives), 5% of clove, 5% of mint, and 5% of purple perilla. After 21 and 75 days of fermentation, the fermentation characteristics, bacterial communities, and ruminal greenhouse gas emissions in vitro incubation of paper mulberry were analyzed. The results showed that the used herbal residues could reduce the protein losses in paper mulberry silage based on the lower contents of ammoniacal nitrogen and nonprotein nitrogen. Compared with control, higher lactic acid and propionic acid contents were observed in the silages treated with mint and purple perilla but with a higher acetic acid content in clove treatment. Real-time sequencing technology (single-molecule real-time) revealed that Lactobacillus was the dominant bacteria in all silages at the genus level, whereas the bacterial abundance in the treated silages differed greatly from control at the species level. Lactobacillus hammesii abundance was the highest in control, whereas Lactobacillus acetotolerans was the first predominant in the treated silages. All the additives enhanced the digestibility of in vitro dry matter significantly. However, purple perilla decreased the production of total gas, methane, and carbon dioxide. The findings discussed earlier suggested that herbal residues have potential effects in improving fermentation quality, reducing protein loss, and modulating greenhouse gas emissions in the rumen of paper mulberry silage by shifting bacterial community composition.

Quality of haylage ofBrachiaria brizanthawith different contents of dry matter in the storage

AbstractThe purpose of this study was to evaluate the quality of Marandu grass (Brachiaria brizantha) haylage according to different dry matter (DM) contents in storage. The design adopted was completely randomized with four treatments and five replications. The treatments were DM contents of the plant at the moment of storage (in natura, 30–40, 40–50 and 50–60% DM). The analyses to assess the quality of the haylage were performed after 90 days of storage. The chemical composition, microbiological population, gas quantification, pH, N-NH3, volatile fatty acids, soluble carbohydrates (CHO) and the aerobic stability were evaluated. The means were compared through the Tukey's test and linear regression. The treatment with 50–60% DM presented the highest DM and CHO contents which were 563.8 and 42.0 g/kg, respectively. There was a higher presence of oxygen in the haylage ofin naturamaterial, which was 4.8%. There was no difference between treatments for the population of lactic acid bacteria; however, the treatment with 50–60% DM had the highest concentration of enterobacteria. The haylage with 30–40% DM and 50–60% DM presented high concentrations of acetic acid. There was no break in aerobic stability for any treatment within 120 h after opening the bales. There was a smaller amount of N-NH3in treatments with 40–50% DM and 50–60% DM. The Marandu grass with a DM content of 50–60% for haylage making demonstrated better quality characterization of conserved forage.

Anti-phytopathogenic and plant growth promoting potential of endophytic fungi isolated from Dysoxylum gotadhora

Phytopathogens have negative impact on crop growth and production. Biological control of plant pathogens, is a safer alternative to chemical treatments, and may also provide additional advantages through plant-growth promotion activities. Recently, endophytes have received due attention to be used as biocontrol agents and plant growth promoters. The present study was designed to determine the antagonistic potential of endophytic fungi isolated from Dysoxylum gotadhora (Buch. Ham.) Mabb. against soil borne phytopathogens, Verticillium dahliae and Fusarium oxysporum, as well as to identify their plant growth promoting features. Dual culture method was used to assess the growth inhibition of phytopathogens in vitro. Results showed that Aspergillus sp. and Porostereum sp. reduced the growth of the phytopathogens with 40–70% inhibition and also produced high indole acetic acid (IAA) content with 19.237 ± 0.253 µg/mL and 18.60 ± 0.098 µg/mL, respectively. This signifies that fungal endophytes can be effectively used as biological control agents and growth promoters. Supplemental data for this article is available online at https://doi.org/10.1080/03235408.2022.2027674 .

Chicken manure-based bioponics: Effects of acetic acid supplementation on nitrogen and phosphorus recoveries and microbial communities.

Bioponics has the potential to recover nutrients from organic waste streams, such as chicken manure and digestate with high volatile fatty acid (VFA) contents through crop production. Acetic acid, a dominant VFA, was supplemented weekly (0, 500, 1000, and 1500mg/L) in a chicken manure-based bioponic system, and its effect on the performance of bioponics (e.g., plant yield and nitrogen and phosphorus availabilities) was examined. Microbial communities were analyzed using 16S rRNA gene sequencing, and the functional gene abundances were predicted using PICRUSt. Although acetic acid negatively affected plant yield, no significant difference (p>0.05) was noted in the average nitrogen or phosphorus concentration. In terms of nutrient recovery, the bioponic systems still functioned well, although higher concentrations of acetic acid decreased plant yield and altered the bacterial communities in plant roots and chicken manure sediments. These data suggest that an acetic acid concentration of<500mg/L or a longer loading interval is recommended for the effective operation of chicken manure and digestate-based bioponics.

Propriedades físico-químicas do glucomanano heterogeneamente acetilado de A. oncophyllus e seu desempenho para encapsulamento de ferro

Abstract Well-known as a food additive, glucomannan has excellent biocompatibility and biodegradability properties. However, glucomannan is easily gelled, which limited its use in high concentration. To reduce the gel formation ability of glucomannan, acetylation was conducted. This work aims to study the effect of acetylation on physicochemical properties of glucomannan. Acetylation was performed in heterogeneous system which glucomannan was immersed in ethanol (96%) with various concentrations of glucomannan (5-25%) and acetic acid (5-99%). This modified glucomannan was subsequently used as an encapsulation matrix for producing iron beads. The results showed that higher concentration of acetic acid in acetylation impacted on higher solubility and viscosity of glucomannan. The transmittance intensity of Infrared (IR) spectra and morphology of glucomannan were changed due to the acetylation and encapsulation process. The highest viscosity of the matrix (484.33 cP) led to the highest Encapsulation Yield (EY) (53.3%). Gompertz’s model fitted to describe the release profile of iron in all samples (R2&gt;0.92) that showed the burst phenomena in the initial release. This work found that acetylated glucomannan had higher solubility and has a potency to protect the iron taste during oral consumption as it releases slower in neutral pH solution.

Thermoresistant, Ethanol-Resistant and Acid-Resistant Properties of Acetic Acid Bacteria Isolated from Fermented Mango Alcohol

Vinegar production is seriously affected by the sensitivity of acetic acid bacteria (AAB) to high temperature, high ethanol concentrations, and high acetic acid concentrations. The aim of this study was to investigate the thermo-ethanol-acid tolerance characters of five AAB strains (VMA1, VMA5, VMA7, VMAM, VMAO) previously isolated from fermented mango alcohol and belonging to Gluconoacetobacter genera. As result, the five AAB strains exhibited good growth and acid production at temperatures up to 45°C; they could tolerate and produce acetic acid at ethanol concentrations up to 20% (v/v). In addition, the studied strains showed growth at acetic acid concentrations up to 4.5% (w/v). Strains VMA7 and VMAO showed the highest resistance properties: they demonstrated acid production at 50°C and VMAO could even grow at 60°C; they tolerated and produced acetic acid at 25% (v/v) ethanol concentration; they showed resistance to acetic acid concentrations up to 6% (w/v). Considering all these properties, the use of these strains would seriously contribute to improving the quality of the vinegar produced and help to reduce the cooling water feeds in vinegar production especially in hot countries in the context of global warming.

Prebiotic effect of porang oligo-glucomannan using fecal batch culture fermentation

Porang glucomannan is a polysaccharide extracted from Amorphophallus oncophylus and its degradation product is porang oligo-glucomannan (POG). It contains glucomannan, which has been used as an emulsifier, thickener, or as a nutritional supplement to counter many diseases. While it is believed to have health benefits, there are only limited studies exploring this aspect of porang glucomannnan (PGM). It was hydrolyzed using β-mannanase to obtain POG under optimal conditions: reaction temperature of 37 °C, reaction time of 4 h, pH 5.5 and E/S of 1:1,000 (w/w). The study aimed to evaluate the fermented POG, which might also generate short-chain fatty acids (SCFA) and to estimate the prebiotic activity score of POG fermented in vitro. The results show that SCFA profiles of POG fermentation gave a high acetic acid concentration (32.64 mM) and butyric acid (6.68 mM) at 12 h, having butyrogenic effects after a rapid fermentation. Mostly the beneficial bacteria grew faster on POG and KOG (konjac oligo-glucomannan) than on PGM or control at the beginning of incubation. Among the substrates screened, POG showed a highly positive prebiotic index of 10.29, increasing bifidobacteria and lactobacilli but reducing bacteroides population. So, POG is a candidate prebiotic since it has bifidogenic, butyrogenicity, and fermentability.