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EN
This review focuses on advances in the synthesis and structural chemistry of zinc alkoxide compounds for use in the catalytic ring-opening polymerization (ROP) of lactides (LAs). This route was used for the preparation of lactic acid based polymers - referred to as polylactides (PLAs). These polyesters have ecofriendly properties such as renewability, biocompatibility, and biodegradability, and are therefore among the most promising green polymers. PLAs have found numerous specialty applications in the biomedical industry, such as biodegradable screws and sutures, scaffolds for tissue engineering, matrices for controlled drug delivery systems, and environmentally friendly food-packaging materials. In industry, PLAs were synthesized by bulk polymerization of LA using tin(II) alkoxides synthesized in situ from tin(II) 2-ethylhexanoate. The toxicity associated with most tin compounds is a considerable drawback in the case of biomedical applications. There has therefore been much research devoted to finding well- defined complexes of high activity containing biologically benign metals. In this context, zinc alkoxides are very attractive non-toxic initiators for the synthesis of polymers that could be used in medical and environmental fields. The most broadly applied representations of zinc initiators for ROP of LA are zinc carboxylates, ß-diketonates, ß-diketiminates, phenolates and bisphenolates, trispyrazolyl- and trisindazolyl-borates, heteroscorpionates, aminophenolates, Schiff base, and iminealkoxylates. The mentioned above initiators were classified and analyzed in the context of their coordination chemistry and revealed catalytic activity in the ROP of LA. The review contains only pioneering/groundbreaking works that allowed for setting new research paths for each of the described groups of initiators, showing how this theme has changed over the last several decades.
EN
The aim of the study presented in this paper was to evaluate the effect of lactic acid concentration in marinade on the quality of baked chicken breast fillets. Poultry fillets were marinated in 1, 2 and 4% lactic acid solution. The evaluation of physical characteristics of fillets included measuring pH, assessing color according to the L*a*b* scale, as well as water absorption and tenderness of meat. The organoleptic evaluation included the intensity and desirability of the aroma, the intensity and desirability of the flavor, as well as the juiciness and tenderness of meat. Lactic acid marinating was shown to affect the brightness (L*), as well as red a* and yellow b* color saturation of the fillets. Marinating in 1 and 2% lactic acid solution had beneficial effects on physicochemical and sensory characteristics of marinated poultry meat after baking, whereas marinating in 4% lactic acid solution caused deterioration of flavor and smell of baked meat.
PL
Celem badań przedstawionych w artykule była ocena wpływu stężenia kwasu mlekowego w marynacie na jakość pieczonych filetów z piersi kurcząt brojlerów. Filety drobiowe marynowano w 1, 2 i 4% roztworze kwasu mlekowego. W ocenie cech fizycznych filetów uwzględniono pomiar pH, ocenę barwy w skali L*a*b* oraz wodochłonność i kruchość mięsa. W ocenie organoleptycznej uwzględniono natężenie i pożądalność zapachu, natężenie i pożądalność smaku oraz soczystość i kruchość mięsa. Wykazano, że marynowanie kwasem mlekowym ma wpływ na jasność (L*) oraz wysycenie barwy czerwonej a* i żółtej b* barwy filetów. Marynowanie w 1 i 2% roztworze kwasu mlekowego miało korzystny wpływ na cechy fizykochemiczne i sensoryczne marynowanego mięsa drobiowego po pieczeniu, natomiast marynowanie w roztworze kwasu mlekowego o stężeniu 4% spowodowało pogorszenie smaku i zapachu mięsa pieczonego.
3
Content available remote Chemiczne i enzymatyczne metody estryfikacji kwasu mlekowego
PL
Szybki rozwój ważnych sektorów gospodarki, takich jak budownictwo, motoryzacja, przemysł farmaceutyczny i spożywczy, związany jest z rosnącym zapotrzebowaniem na rozpuszczalniki, powłoki, farby, półprodukty i różnego typu dodatki. Estry kwasu mlekowego, jako nietoksyczne, biodegradowalne zamienniki rozpuszczalników petrochemicznych, są bardzo ważną grupą związków doskonale wpisujących się w założenia strategii zrównoważonego rozwoju. Omówiono możliwości syntezy estrów kwasu mlekowego metodami chemicznymi i enzymatycznymi. Wskazano zalety i wady poszczególnych rozwiązań oraz możliwości ich przemysłowego zastosowania.
EN
A review, with 53 refs., of methods for lactic acid prodn. and esterification with particular emphasis on the types of catalysts used and techn. aspects.
4
Content available remote Quality of silages made from meadow sward from south-eastern Poland
EN
Weather conditions prevailing in Poland often cause that meadow sward designated for silage is harvested too late, which decreases the quality of prepared silage. The aim of the research was to assess the quality of silages from dried meadow sward. The silages were ensiled in large cylindrical bales in selected individual farms specializing in milk production. The farms where the research was carried out were located in three voivodeships: slaskie, malopolskie and podkarpackie. In the prepared plant material, the basic chemical composition was determined using the method. When comparing the mean values, it was established that silages from the investigated region had a favourable content of total protein, the highest concentration was recorded for silages from Slask, followed by Malopolska and Podkarpacie. A slightly elevated concentration of crude fibre, fraction of acid detergent fibre (ADF) and neutral detergent fibre (NDF), was recorded. This fact shows that farmers collect raw material, particularly from the first cut, too late. Nutrient value of silages from meadow sward decreases with progressing vegetation. Higher protein and energy losses during sward ensiling were also observed at considerable drying of the plant material. In most cases, silages from the studied farms had a low content of monosaccharides. The carried out chemical analyses showed that in overall assessment the studied silages are of good quality; silages prepared from meadow sward from the third cut had the highest value. Proper technology of preservation of meadow sward is one of important factors in the production of feed for ruminants.
5
Content available remote Concepts of modern technologies of obtaining valuable biomass-derived chemicals
EN
In this paper, we present the review of modern technologies for obtaining valuable biomass-derived chemicals, such as furfural, levulinic acid, adipic acid, dihydroxyacetone, lactic acid and acrylic acid. We have included our own research approach using the nano-design of zeolites for the dehydration of lactic acid into acrylic acid.
PL
W niniejszej pracy przedstawiono przegląd nowoczesnych technologii uzyskiwania cennych związków chemicznych pochodzących z biomasy, takich jak furfural, kwas lewulinowy, kwas adypinowy, dihydroksyaceton, kwas mlekowy i kwas akrylowy. Zaprezentowano również własne podejście badawcze obejmujące projektowanie w skali nanoskopowej zeolitów do odwadniania kwasu mlekowego do kwasu akrylowego.
EN
The aim of this work was to develop the method of lactic acid (LA) separation from fermented whey. CMI-7000 Cation Exchange Membrane and AMI-7001 Anion Exchange Membrane were employed in electrodialysis process. Experiments showed that the selected membranes separated organic acids effectively (including LA) from other organic ingredients present in medium. Selecting an appropriate volume of a receiving chamber could lead to LA concentration. Moreover, membrane fouling during separation was investigated. This phenomenon is negligible which is the main advantage of this process. As it was shown during batch processes, with the voltage increase, the rate of electrodialysis increases as well. It prompts to a reduction of residence time in electrodialyzer during a continuous separation.
EN
Purpose: This publication provides a description of RDC Glokor’s own research into the effectiveness of the lactic fermentation process of lactose, lactic acid concentration and polylactide (PLA) production by ring-opening polymerization obtained from the condensation of two molecules of lactic acid. Furthermore, this publication sets out to determine potential applications of the PLA as a commercial material with a selection of thermal properties. Design/methodology/approach: In the described research works, a lactic fermentation process was used in which lactose is converted to lactic acid with the participation of Lactic Acid Bacteria. Polylactide was obtained indirectly by Ring Opening Polymerization and by direct polymerization, straight from lactic acid, omitting the intermediate stages. Next, the obtained lactide and polylactide were examined by spectroscopic methods (IR, NMR) to determine their purity. Thermal methods (TG, DSC) to determine thermoplastic properties, i.e. softening point, decomposition temperature and glass transition temperature. Findings: Obtained from waste whey, PLA and its copolymers are excellent biodegradable polymers that have the potential to be used in medicine as resorbable surgical strands, biopolymers for implant production, as well as in many industries including for the production of biodegradable bottles and disposable packaging, 3D printer cartridges. Research limitations/implications: The research on lactic acid and lactide polymerization described in this article is still a new issue that requires further research to optimize PLA processes with industry-specific thermoplastic and physicochemical properties. Originality/value: In the basic waste processing of milk, there is a large volume of whey sour, which is ecologically dangerous for waste treating. Due to the high content of lactose (up to 6%) this waste can be used as a raw material in the lactic fermentation process in which lactose is converted to lactic acid with the participation of lactic acid bacteria. Lactic acid can be concentrated and subjected to a dehydration process to lactide, which in the final stage is subjected to the process of ring-opening polymerization in order to produce biodegradable polylactide. The described process of carrying out the lactose contained in PLA whey is an innovative way to obtain a biodegradable usable polymer, which can be used to replace plastics such as polypropylene and polyethylene.
PL
Badano procesy kondensacji kwasów cytrynowego i mlekowego w stopie oraz metodą sprzęgania w obecności dicykloheksylokarbodiimidu. Otrzymane produkty analizowano za pomocą technik magnetycznego rezonansu jądrowego (1H NMR), spektroskopii mas (MALDI ToF) oraz chromatografii żelowej (GPC). Wykazano, że kondensacja w stopie prowadzi na ogół do skomplikowanej mieszaniny kopolimerów oraz homopolimerów kwasu mlekowego. Połączenie obu metod pozwala natomiast otrzymać, z wysoką wydajnością, kopolimery o budowie rozgałęzionej o wagowo średnich masach molowych 9–27 kg/mol i wartościach Mw/Mn = 1,3–2,0. Metodą sprzęgania uzyskano także amfifilowe kopolimery zawierające hydrofobowy rdzeń złożony z merów kwasów cytrynowego i mlekowego oraz hydrofilowe segmenty polioksyetylenowe. Produkty te tworzą w wodzie stabilne koloidalne dyspersje o średnicach cząstek rzędu 50–500 nm.
EN
The processes of condensation of citric and lactic acids carried out in melt or by coupling in the presence of dicyclohexylcarbodiimide have been investigated. The obtained products were analyzed using 1H NMR, MALDI ToF and GPC techniques. It has been shown that the condensation in melt leads generally to acomplicated mixture of lactic acid copolymers and homopolymers. However, the combining of both methods allows to obtain in high yield the copolymers with branched structure, weight-average molar masses in the range 9–27 kg/mol and Mw/Mn values between 1.3 and 2.0. By using the coupling method, amphiphilic copolymers containing ahydrophobic core composed of citric and lactic acid monomeric units and hydrophilic polyoxyethylene segments were obtained as well. These products form stable colloidal aqueous dispersions with particle diameters ranging from 50 to 500 nm.
EN
The processing of Citrofortunella mircocarpa fruit juice generates large volume of solid waste, causing disposal problem. Several studies have demonstrated that wastes from agricultural and food processing industries such as fruit and vegetable peels contain high amount of polysaccharides that can be transformed into useful chemicals, including lactic acid, through fermentation. Lactic acid is widely used in various industries, such as in the manufacture of biodegradable plastic, and the demand for this chemical justifies the search of renewable feedstock for its biotechnological production. This study aimed to produce lactic acid from C. microcarpa fruit waste biomass through fermentation with Lactobacillus plantarum. The hydrolysate from C. microcarpa fruit waste was prepared, inoculated with different amounts of L. plantarum cell suspension, and incubated for three days. Lactic acid production was monitored daily. The lactic acid produced from the fermentation was recovered as calcium lactate and lactic acid crystals. The identity of the crystals was evaluated using Fourier transform infrared spectroscopy (FTIR) spectroscopy and paper chromatography. The highest lactic acid production was observed in fermentation mixtures containing the highest number of L. plantarum cells. Within three days of fermentation, the amount of lactic acid production increased with increasing period of incubation. Partial characterization of the crystals recovered from the fermentation mixtures by FTIR spectroscopy showed that the peaks in the spectrum were consistent with the chemical structure of lactate. Paper chromatography results likewise confirmed that the crystals are lactate. C. microcarpa fruit waste can afford lactic acid when fermented with L. plantarum. The results of the study may serve as basis for the development of technology for the utilization of C. microcarpa fruit waste biomass as renewable resource for industrial production of lactic acid.
EN
The efficiency of lactic acid solutions nanofiltration with dynamically formed zirconium (IV) hydrous oxide polyacrylate (ZrIV/PAA) membranes application were considered in this paper. The results of investigations on flux decline in nanofiltration of lactic acid solutions under conditions resulting in low and high lactic acid rejection are reported. In the long term experimental research on pressure driven membrane processes the main reason of permeate flux reduction is an accumulation of concentration polarization and fouling effects. The experimental permeate flux versus time curves were analyzed in the frame of resistance-in-series model with the aim to develop the characteristic fouling and concentration polarization resistances. The analysis of experimental data and results of calculations showed that both: concentration polarization and fouling phenomena in investigated system depend on hydrodynamic conditions and properties of filtered solutions and (ZrIV/PAA) membrane.
EN
In batch fermentation of whey, selection of suitable species at desired conditions such as substrate, product concentrations, temperature and inoculum size were investigated. Four Lactobacillus species and one Lactococcus species were screened for lactic acid production. Among them L. bulgaricus ATCC 11842 were selected for further studies. The optimal growth of the selected organism for variable size of inocula was examined. The results indicated that inoculum size had insignificant effect on the cell and lactic acid concentration. The effect of temperature was also studied at 32, 37, 42 and 47°C. Results showed that the concentration of cell dry weight increased with increment of temperature from 32 to 42°C. The maximum cell and lactic acid concentration was obtained at 42°C. The effect of initial substrate concentration on lactic acid production was also examined. The optimum initial lactose concentration was found to be 90 g/l.
12
Content available remote Corrosion resistance of titanium alloys in the artificial saliva solution
EN
Purpose: The purpose of this article was to characterize the corrosion behaviour and compare two biomedical titanium alloys (Ti-6Al-4V and Ti-10Mo-4Zr) in an artificial saliva solution (MAS) containing lactic acid and hydrogen peroxide (H2O2) used in dentistry. The addition of these two compounds simulate the situation, where the alloy is implanted in the human body and hydrogen peroxide is generated by the inflammatory reaction and lactic acid is release by bacterial in the oral cavity. Design/methodology/approach: In this studies were used following electrochemical techniques: Open Circuit Potential (OCP), Linear Sweep Voltamperometry (LSV), Chronoamperometry at constant potential and Electrochemical Impedance Spectroscopy (EIS). Electrochemical impedance spectra were carried out at the 0.5 V vs. Ag/AgCl potential. The EIS data were fitted using the ZViev software. Findings: The results presented in the work demonstrate that the titanium alloys have a good corrosion resistance. The corrosion behaviour was determined by surface condition of alloys and presence different chemical compounds in the solution. For Ti-10Mo-4Zr titanium alloy in MAS with different concentration of hydrogen peroxide in anodic domain it was seen more clearly. Research limitations/implications: In the future passive films of both titanium alloys will be investigated by: X-ray photoelectron spectroscopy (XPS) and scanning electron spectroscopy (SEM). Originality/value: The corrosion behaviour of biomedical titanium alloy contains molybdenum and zirconium selected as safe alloying elements for human body is presented and compared to commercial Ti-6Al-4V alloy. The corrosion resistance of the titanium alloys was investigated in the artificial saliva solution with addition of lactic acid and hydrogen peroxide.
PL
Od wielu lat bakterie fermentacji mlekowej cieszą się dużym uznaniem w przemyśle spożywczym, głównie ze względu na syntezę charakterystycznych metabolitów. Produkowane związki pełnią funkcję naturalnych konserwantów, nadają produktom unikatowe cechy organoleptyczne oraz wpływają na zwiększenie wartości odżywczej żywności. Istnieje wiele metabolitów bakterii LAB, jednakże na szczególną uwagę zasługują: kwas mlekowy, bakteriocyny, kwas foliowy, aldehyd octowy i diacetyl, których zastosowanie w przemyśle omówiono w niniejszym artykule.
EN
For many years, lactic acid bacteria are widely recognized in the food industry, mainly due to the synthesis of typical metabolites. Produced compounds act as natural preservatives, give unique organoleptic characteristics and increase the nutritional value of food. There is a wide range of LAB metabolites which should be pointed out: lactic acid, bacteriocins, folic acid, acetaldehyde and diacetyl. Their industrial application is discussed in this article.
PL
Obecność mikotoksynotwórczych grzybów pleśniowych w żywności stanowi poważny problem, nie tylko z punktu widzenia bezpieczeństwa zdrowotnego, ale również ze względów ekonomicznych. Opracowanie skutecznego sposobu kontroli poziomu pleśni oraz ich mikotoksyn jest od wielu lat przedmiotem licznych badań naukowych. Stosowane techniki chemiczne i fizyczne, nie są w pełni efektywne, dlatego duże nadzieje pokłada się w metodach biologicznych. Wśród nich, coraz większe zainteresowanie budzi wykorzystanie bakterii fermentacji mlekowej. Odpowiednio wyselekcjonowane szczepy bakteryjne mają zdolność hamowania wzrostu pleśni oraz tworzenia przez nie mikotoksyn, a ponadto detoksyfikacji środowiska z mikotoksyn.
EN
Presence of mycotoxigenic fungi in food is a serious problem, not only from the point of view of health security, but also for economic reasons. Develop an effective way to control mold growth and mycotoxins for many years is the subject of numerous scientific studies. The chemical and physical techniques used are not fully effective, which is why big hopes for the bioassays. Among them, more and more interest is the use of lactic acid bacteria. Appropriately selected bacterial strains have the ability to inhibit the growth of molds and mycotoxins formation, and further environmental detoxification of mycotoxins.
PL
Serwatka kwaśna jest groźnym ekologicznie odpadem, będącym produktem ubocznym powstającym w przemyśle mleczarskim. Z uwagi na wysoką zawartość laktozy, odpad ten może być wykorzystywany jako surowiec w procesie fermentacji mlekowej, w którym ulega dalszej przemianie do kwasu mlekowego, przy udziale bakterii fermentacji mlekowej. Niniejsza publikacja stanowi przegląd literaturowy dotyczący procesu fermentacji mlekowej oraz opis badań własnych nad efektywnością procesu fermentacji mlekowej laktozy, pozyskanej z serwatki poprodukcyjnej, do kwasu mlekowego.
EN
Acid whey is an environmentally hazardous waste which is a by-product produced in the dairy industry. Due to the high lactose content, the waste can be used as a raw material for lactic fermentation process, where it is converted further to lactic acid using lactic acid bacteria. This publication is a literature review on lactic acid fermentation process and includes description of own research on efficiency of lactic acid fermentation of lactose, obtained from spent whey, to lactic acid.
PL
Ze względu na powszechne wykorzystanie stopów tytanu w stomatologii, w pracy podjęto badania elektrochemiczne stopów tytanu: Ti-10Mo-4Zr i Ti-6Al-4V, których celem było określenie właściwości korozyjnych podczas ekspozycji w fizjologicznym roztworze sztucznej śliny, w temperaturze 37 °C, pH = 8,0 i swobodnym dostępie tlenu, a następnie modyfikacji roztworu poprzez dodatek kwasu mlekowego oraz fluorku sodu. Odporność korozyjną obu stopów porównano na podstawie badań potencjału korozyjnego i potencjodynamicznych krzywych polaryzacyjnych wykonanych techniką liniowej woltamperometrii (LSV).
EN
Titanium alloys are used in medicine and dentistry due to perfect combination of their high strength, corrosion resistance and biocompatibility. Currently, titanium alloys are among the most attractive metallic materials used to manufacture such implants as artificial hip joints, knee joints, intervertebral discs, screws securing the fracture. Most kinds of screws used in dentistry for basic fixing of ceramic dental prostheses are made from titanium alloys. Widespread use of titanium alloys in dentistry is the reason for electrochemical research on two titanium alloys: Ti-6Al-4V and Ti-10Mo-4Zr. The aim of the research was to determine the corrosion when the alloy is exposed to physiological artificial saliva solution at the temperature of 37 °C, pH = 8.0 and in aerated solution and modification of saliva solution: added lactic acid and sodium fluoride.
PL
W pracy wykazano wpływ stosowanych dodatków do kapusty: buraka ćwikłowego, jabłka, marchwi na zwiększenie zawartość witaminy C i kwasu mlekowego, a dodatek nasion kminku, powodował wzrost zawartości witaminy C. Proces pasteryzacji kwaszonej kapusty przechowywanej w pomieszczeniu (z temperaturą 15°C), w porównaniu z próbami przetrzymywanymi w piwnicy (10°C) i w lodówce (5°C), spowodował większe straty zawartość witaminy C i kwasu mlekowego. Najniższe straty witaminy C odnotowano w próbach przechowywanych w piwnicy.
EN
It was proved that the additives of horseradish, apple and carrot to cold beetroot sauerkraut caused the increase of vitamin C and lactic acid content, also the addition of caraway seeds caused the rise of vitamin C content. The pasteurization of pickled cabbage stored in a room (at temperature 15°C), compared with those stored in a basement (10°C) and in a refrigerator (5°C) caused greater losses of vitamin C and lactic acid. The lowest losses of vitamin C were noticed in samples stored in the basement.
EN
The decrease of seed quality during storage is strongly associated with damage caused by free radicals. Some compounds of natural origin, known due to their antioxidative and antifungal properties, may be potentially used in organic production for seed treatment as an alternative to pesticides. The aim of the experiment was to study an ability of hydrogen peroxide and organic acid to improve germination, vigour and health of non-deteriorated and deteriorated zinnia seeds. Two seed samples, cv. Illumination and Orys, varying in initial infestation with fungi were tested. For deterioration seeds were kept at 30°C and 80% RH for 30 days. Seed quality tests were performed before and after deterioration for controls and seeds soaked in 3.0% hydrogen peroxide solution and in 1.0 and 5.0% solutions of ascorbic and lactic acids for 10, 30 and 60 min. The controls were untreated seeds, seeds soaked in 0.2% solution of Kaptan zawiesinowy 50 WP for 30 min and seeds soaked in distilled water for 10, 30 and 60 min. Treating zinnia seeds with organic acids more significantly affected seed germination and health after deterioration than before, and improvement of germination capacity was usually correlated with decrease of the percentage of abnormal diseased seedlings. Deterioration had no influence on mean germination time, whereas in particular cases treating seeds with hydrogen peroxide and organic acids negatively affected this parameter. After deterioration regardless of treatment increased number of seeds free from fungi. Lactic acid followed by hydrogen peroxide and ascorbic acid effectively limited growth of A. alternata, A. zinnia and Fusarium spp. on zinnia seeds, however at higher concentration negatively affected seed germination and vigour. Moreover, treating seeds with hydrogen peroxide and organic acids many a time increased seeds infestation with B. cinerea.
PL
Pogorszenie jakości nasion podczas przechowywania jest ściśle związane z powstawaniem wolnych rodników. Niektóre związki o naturalnym pochodzeniu, znane ze swych właściwości antyoksydacyjnych i antygrzybowych, można potencjalnie wykorzystać do traktowania nasion w produkcji organicznej jako alternatywę dla pestycydów. Celem doświadczenia było określenie zdolności nadtlenku wodoru i kwasów organicznych do poprawy kiełkowania, wigoru i zdrowotności nasion cynii przed starzeniem i po starzeniu. Badano dwie próbki nasion cynii, odm. Illumination i Orys, różniące się wyjściowym zasiedleniem przez grzyby. W celu starzenia przetrzymywano nasiona przez 30 dni w temperaturze 30°C i w warunkach 80% wilgotności względnej powietrza. Testy określające jakość nasion przeprowadzono przed i po starzeniu dla kontroli oraz nasion moczonych przez odpowiednio 10, 30 i 60 min w 3,0% roztworze nadtlenku wodoru oraz 1,0 i 5,0% roztworach kwasów askorbinowego i mlekowego. Kontrole stanowiły nasiona nietraktowane, nasiona moczone w 0,2% roztworze preparatu Kaptan zawiesinowy 50 WP przez 30 min oraz nasiona moczone w wodzie destylowanej przez odpowiednio 10, 30 i 60 min. Traktowanie nasion kwasami organicznymi w większym stopniu wpływało na nasiona po starzeniu niż przed, a poprawa zdolności kiełkowania związana była na ogół ze zmniejszeniem liczby kiełków anormalnych chorych. Starzenie nie miało wpływu na średni czas kiełkowania nasion, jakkolwiek w poszczególnych przypadkach traktowanie nasion nadtlenkiem wodoru i kwasami organicznymi niekorzystnie wpływało na ten parametr. Po starzeniu, bez względu na traktowanie, wzrastała liczba nasion wolnych od grzybów. Kwas mlekowy, a następnie nadtlenek wodoru i kwas askorbinowy efektywnie ograniczały wzrost A. alternata, A. zinnia i Fusarium spp. na nasionach cynii, jednak 5% kwas mlekowy zastosowany dłużej niż 30 min negatywnie wpływał na kiełkowanie i wigor nasion. Traktowanie nasion nadtlenkiem wodoru i kwasami organicznymi niejednokrotnie zwiększało zasiedlenie nasion przez B. cinerea.
PL
Badano proces ultrafiltracji modelowych roztworów koncentratu białkowego serwatki z dodatkiem kwasu mlekowego. Przeprowadzono analizę wpływu ciśnienia oraz ci/f-p//'membrany na wydajność i selektywność procesu separacji membranowej. Wynika z niej, że z punktu widzenia możliwości zastosowania w bioprocesie wspomaganym membranami do otrzymywania kwasu mlekowego z odpadowej serwatki w procesie ciągłym, lepszą charakterystykę posiada membrana o cut-off 1 kDa w warunkach ciśnienia transmembranowego 0,3 MPa.
EN
The ultrafiltration of model protein conccntratc solutions of whey with lactic acid addition was investigated. An influence of pressure and membrane cutoff on yield and selectivity of membrane separation process was analyzed. From a point of view of membrane-supported continuous bioprocess in the production of lactic acid from waste whey, it can be stated that the better characteristic represents the membrane of 1 kDa cut-off at transmembrane pressure of 0.3 MPa.
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