The simple method of vegetable oils and oleochemical products acid value determination

2021 ◽  
pp. 69-74
Author(s):  
S.O. Zubenko ◽  

Acid value is one of the key technical characteristic of vegetable oils and oleochemicals, obtaining on its basis. The existing standard methods of acid value measurement are relatively complicated and have some disadvantages. There are including utilization of the significant amounts of solvents, throwing out as wastes, and necessity in special equipment for determination. Also, a special issue is visual indication of the equivalence point of indicator transfer from acid to alkali form for intensive colored oils’ samples. Visual indication of the color transfer of phenol-phthalein as indicator (from colorless to pink) is quite difficult. The color transfer of thymolphthalein (from yellow to green) in such condition is not determined. Using of alkali blue 6B is complicated by the necessity of use ethanol and aromatic compounds mixture. In current work the rapid and simple method of acid value determination was proposed. It consists in alkali-acid titration of the sample by sodium butoxide solution in n-butanol with bromothymol blue, n-butanol is also using as solvent. The method was tested on 3 series of the mixtures of the refined sunflower oil and free fatty acids (distilled fatty acids of sunflower and rapeseed oils and chemical grade oleic acid). The fatty acid content in tested mixtures was in range 1-50 % wt. Some disadvantages of traditional methods, such as the necessity of mixed solvents’ and relatively complicated laboratory equipment use, titration in a hot state, effect of temperature changes in the laboratory and difficulties with visual indication of color transfer, were overcame. Proposed method requires only the simplest laboratory glassware (conic flasks, non-calibrated pipettes, hermetically sealed glass vessels for titrant) and technical laboratory scales (weighting accuracy ±0.01 g). The method allows to determine the acid value in wide range of samples, including the samples with intense coloration. The relatively high accuracy of acid value determination was shown. The method sensitivity is 0.02-0.10 mg KOH/g. The time for analyze is enough short (about 5-15 minutes).

2021 ◽  
Vol 903 ◽  
pp. 81-86
Author(s):  
Kristaps Māliņš ◽  
Ilze Malina ◽  
Mara Legzdina

The catalytic hydrotreatment of sunflower (SO), linseed (LO), coconut (CO), rapeseed (RO), and its soapstock derived acid oil (RS) over commercial Ni65%/SiO2-Al2O3 catalyst was investigated to evaluate utilization feasibility of various vegetable oil feedstocks with different fatty acid content, composition, and saturation for marketable hydrocarbon production. The active metal loading of catalyst was characterized by XRF and its textural properties by N2 sorption analysis. The hydrotreatment tests of different vegetable oils were carried out in solvent free medium, under initial H2 pressure 10 MPa, at operating temperature 340 oC, and residence time 15 min using catalyst amount 5%. GC-FID and GC-MS analysis were used for estimation of dominant n-pentadecane, n-hexadecane, n-heptadecane, n-octadecane, and other hydrocarbon contents in obtained samples. Under studied hydrotreatment conditions complete conversion of different vegetable oils into marketable liquid renewable hydrocarbons without presence of oxygen containing substances was achieved. Highly active Ni65%/SiO2-Al2O3 has remarkable selectivity to hydrocarbons produced by reaction pathways, where elimination of carbonyl groups occurs. The saturation of fatty acids in feedstock determines H2 consumption, but influence on produced hydrocarbon production is insignificant. Depending on the fatty acid composition different saturated linear hydrocarbons with wide range of carbon chain length C5-C19 and similar calorific value 47.16-47.34 MJ/kg were produced in process. Overall liquid hydrocarbon yields were from 44.6 % to 78.1 %. The highest overall liquid saturated linear hydrocarbon yield was observed for feedstock with high amount of long chain fatty acids – SO, LO, RO and RS. Pure hydrocarbons obtained from vegetable oils depending on hydrocarbon composition can be used in various areas.


Foods ◽  
2021 ◽  
Vol 10 (4) ◽  
pp. 881
Author(s):  
Roberta Tolve ◽  
Fernanda Galgano ◽  
Nicola Condelli ◽  
Nazarena Cela ◽  
Luigi Lucini ◽  
...  

The nutritional quality of animal products is strongly related to their fatty acid content and composition. Nowadays, attention is paid to the possibility of producing healthier foods of animal origin by intervening in animal feed. In this field, the use of condensed tannins as dietary supplements in animal nutrition is becoming popular due to their wide range of biological effects related, among others, to their ability to modulate the rumen biohydrogenation and biofortify, through the improvement of the fatty acids profile, the derivate food products. Unfortunately, tannins are characterized by strong astringency and low bioavailability. These disadvantages could be overcome through the microencapsulation in protective matrices. With this in mind, the optimal conditions for microencapsulation of a polyphenolic extract rich in condensed tannins by spray drying using a blend of maltodextrin (MD) and gum Arabic (GA) as shell material were investigated. For this purpose, after the extract characterization, through spectrophotometer assays and ultra-high-performance liquid chromatography-quadrupole time-of-flight (UHPLC-QTOF) mass spectrometry, a central composite design (CCD) was employed to investigate the combined effects of core:shell and MD:GA ratio on the microencapsulation process. The results obtained were used to develop second-order polynomial regression models on different responses, namely encapsulation yield, encapsulation efficiency, loading capacity, and tannin content. The formulation characterized by a core:shell ratio of 1.5:5 and MD:GA ratio of 4:6 was selected as the optimized one with a loading capacity of 17.67%, encapsulation efficiency of 76.58%, encapsulation yield of 35.69%, and tannin concentration of 14.46 g/100 g. Moreover, in vitro release under varying pH of the optimized formulation was carried out with results that could improve the use of microencapsulated condensed tannins in animal nutrition for the biofortification of derivates.


2020 ◽  
Vol 11 (1) ◽  
pp. 188
Author(s):  
Piotr Skałecki ◽  
Agnieszka Kaliniak-Dziura ◽  
Piotr Domaradzki ◽  
Mariusz Florek ◽  
Ewa Poleszak ◽  
...  

The aim of the study was to assess the influence of the addition of fish raw materials (roe or fish meat) on the quality and nutritional value of pork pâtés. The control group (n = 4) consisted of pork pâtés, I experimental group (n = 6) of pâtés with 20% addition of roe (perch and pike), and II group of pâtés with 20% addition of fish (perch and pike meat) (n = 6). The pâtés’ pH, color, and profiled texture analysis were instrumentally measured and water, protein, fat, ash, and fatty acid content were determined by reference methods. To assess the oxidative stability of lipids the measurement of peroxide number, thiobarbituric acid reactive substances and content of conjugated dienes and trienes was used. The degree of fat hydrolysis was determined on the basis of acid value. Sensory analysis was carried out using the scaling method, taking into account 12 unit quality characteristics. Products with roe and meat contained less fat (accordingly 15.9% and 14.1%) and showed lower calorific value (accordingly 225.6 and 208.6 kcal/100 g) compared to pork pâtés (20.2% of lipids, 267 kcal/100 g). Moreover, the addition of fish raw materials improved the index of nutritional quality for protein (from 3.2 to 3.9) and beneficially reduced the nutritional index for fat (from 2.2 to 1.9). Fish constituents modified, to a certain extent, the color, texture, and sensory properties of pâtés, while maintaining full acceptability in consumer assessment. The addition of fish roe significantly increased the healthful quality by improving the fatty acid profile of pâtés, in which the significantly highest content of n-3 fatty acids, including eicosapentaenoic and docosahexaenoic acids (accordingly 252.21, 43.17, and 107.94 mg/100 g product), as well the highest concentration of saturated branched chain fatty acids were determined (18.75 mg/100 g product).


2016 ◽  
Vol 61 (No. 3) ◽  
pp. 99-105 ◽  
Author(s):  
M. Müller ◽  
Š. Horníčková ◽  
P. Hrabě ◽  
J. Mařík

The research was performed to examine the physical, mechanical and chemical properties of seeds and kernels of Jatropha curcas. The test parameters were the dimensions of the seeds and kernels, required energy for oil extraction, determination of fatty acids in the oil by gas chromatography method, determination of the iodine value, determination of the acid value, determination of total polyphenols by the Folin & Ciocault reagent and determination of tocopherols and tocotrienols (vitamin E) by High-performance liquid chromatography. It was ascertained that the size of the seed and kernel varies considerably. Pressing of whole seeds needs more energy (50%) than pressing of kernels. From a chemical point of view it seems to be very appropriate for a production of biofuels. Jatropha curcas contains more polyphenols and vitamin E, which act as antioxidants, than the rape. Due to the low content of unsaturated fatty acids it is chemically suitable to replace the rape-seed oil with Jatropha curcas oil.


1999 ◽  
Vol 58 (2) ◽  
pp. 363-370 ◽  
Author(s):  
J. D. Wood ◽  
M. Enser ◽  
A. V. Fisher ◽  
G. R. Nute ◽  
R. I. Richardson ◽  
...  

Meat quality describes the attractiveness of meat to consumers. The present paper focuses on two major aspects of meat quality, tenderness and flavour. Both aspects of quality can be influenced by nutrition, principally through its effects on the amount and type of fat in meat. In several countries, high levels of intramuscular fat (marbling fat), i.e. above 30 g/kg muscle weight inlongissimus, are deemed necessary for optimum tenderness, although poor relationships between fat content and tenderness have generally been found in European studies, where fat levels are often very low, e.g. below 10 g/kg in UK pigs. Muscle lipid may be a marker for red oxidative (type 1) muscle fibres which are found at higher concentrations in tender muscles and carcasses. Nutritional treatment can be used to manipulate the fatty acid content of muscle to improve nutritional balance, i.e. increase the polyunsaturated (PUFA) : saturated fatty acid value and reduce then−6 :n−3 PUFA value. Increasing PUFA levels may also change flavour because of their greater susceptibility to oxidative breakdown and the generation of abnormal volatile compounds during cooking. This situation particularly applies to then−3 PUFA which are the most unsaturated meat lipids. In pigs, a concentration of 3 mg α-linolenic acid (18 : 3)/100 mg in muscle and fat tissue fatty acids can easily be achieved by including whole linseed in the diet. This level has led to abnormal odours and flavours in some studies, but not in others. In cattle and sheep, feeding whole linseed raised 18 : 3 concentrations in muscle fatty acids from about 0.7 mg/100 mg to > 1 mg/100 mg. As with pigs, this diet also increased levels of long-chainn−3 PUFA formed from 18 : 3, including eicosapentaenoic acid (20 : 5). Although this increase led to greater oxidative breakdown of lipids during storage and the generation of large quantities of lipid-derived volatile compounds during cooking, there were no deleterious effects on odour or flavour. When 18 : 3 levels are raised in lamb and beef because of grass feeding, the intensity of the flavours increases in comparison with grain-fed animals which consume and deposit relatively more linoleic acid (18 : 2). In ruminants, very high levels of 18 : 2 produced by feeding protected oil supplements cause the cooked beef to be described as oily, bland or pork-like.


1998 ◽  
Vol 81 (4) ◽  
pp. 873-879 ◽  
Author(s):  
Ilya Kuselman ◽  
Yakov I Tur’yan ◽  
Oleg Y Berezin ◽  
Lina Kogan ◽  
Avinoam Shenhar

Abstract The acid value (AV) of vegetable oils is determined without titration by using a new reagent consisting of triethanolamine in a solution of water and isopropyl alcohol. When the oil sample is mixed with the reagent in the pH-metric cell, free fatty acids from the sample are extracted into the reagent ( 3 - 4 min). The initial pH, called conditional pH´, is measured, a standard acid (HC1) is added, and the final pH, pH´2, is measured. AV is calculated from the difference between pH´! and pH´2. The method is applicable for quality control of vegetable oils during their production, trade, and use


2000 ◽  
Vol 63 (2) ◽  
pp. 216-221 ◽  
Author(s):  
MANUELA E. PINTADO ◽  
F. XAVIER MALCATA

Vacuum packaging was assayed at 4°C and was tested in comparison to unpackaged counterparts, in both microbiological and physicochemical terms, in studies pertaining to the preservation of Requeijão, a traditional Portuguese whey cheese. Bacteria were absent (i.e., <10 CFU/g) in whey cheeses on the day of manufacture as a result of thermal processing. After storage, both unpackaged and packaged cheeses exhibited high viable counts of Bacillus, Pseudomonas, Enterobacteriaceae, and lactic acid bacteria (especially lactococci). Yeasts, staphylococci, enterococci, and spore-forming clostridia were severely inhibited by the package vacuum combined with the increasing acidification developed therein. Whey cheeses packaged under vacuum underwent substantial acidification, slight depletion of lactose, and no significant variation in moisture content or texture; conversely, unpackaged whey cheeses exhibited substantial loss of water and a concomitant increase in rigidity. Vacuum packaging strongly inhibited lipolysis (even if viable counts of some microbial groups were high); saturated fatty acids (mainly C16:0 and C14:0) accounted for ca. 73% of the total free–fatty acid content, whereas the most concentrated unsaturated fatty acids were C18:1 and C18:2 (ca. 14% each). The conclusions generated in our study are, in general, useful for a wide range of whey cheeses worldwide: i.e., Requéson (Spain), Ricotta (Italy), Broccio (France), and Anthotyro (Greece). In addition, our conclusions are particularly helpful in terms of improving the safety of Requeijão, a widely acclaimed dairy specialty.


2017 ◽  
Vol 63 (12) ◽  
pp. 1009-1024 ◽  
Author(s):  
Parveen K. Sharma ◽  
Riffat I. Munir ◽  
Teresa de Kievit ◽  
David B. Levin

Pseudomonas chlororaphis PA23 was isolated from soybean roots as a plant-growth-promoting rhizobacterium. This strain secretes a wide range of compounds, including the antibiotics phenazine-1-carboxylic acid (PCA), pyrrolnitrin, and 2-hydroxyphenazine. We have determined that P. chlororaphis PA23 can synthesize medium-chain-length polyhydroxyalkanoate (PHA) polymers utilizing free fatty acids, such as octanoic acid and nonanoic acid, as well as vegetable oils as sole carbon sources. Genome analysis identified a pha operon containing 7 genes in P. chlororaphis PA23 that were highly conserved. A nonpigmented strain that does not synthesize PCA, P. chlororaphis PA23-63, was also studied for PHA production. Pseudomonas chlororaphis PA23-63 produced 2.42–5.14 g/L cell biomass and accumulated PHAs from 11.7% to 32.5% cdm when cultured with octanoic acid, nonanoic acid, fresh canola oil, waste canola fryer oil, or biodiesel-derived waste free fatty acids under batch culture conditions. The subunit composition of the PHAs produced from fresh canola oil, waste canola fryer oil, or biodiesel-derived free fatty acids did not differ significantly. Addition of octanoic acid and nonanoic acid to canola oil cultures increased PHA production, but addition of glucose did not. PHA production in the phz mutant, P. chlororaphis PA23-63, was greater than that in the parent strain.


2021 ◽  
Author(s):  
Emily Morris

Climate change will produce a wide range of challenges for grassland ecosystems, including increased global surface air temperature. Increased temperature can increase cell membrane fluidity in plants and other organisms; a response known as homeoviscous adaptation. However, this phenomenon has not been extensively studied in grassland plant species and has not been widely observed in plants from a climate warming perspective. I exposed seven species of agricultural forage plants to a temperature gradient consistent with climate change estimates for Southern Ontario. I compared relative fatty acid composition between temperature conditions, paying particular attention to the relative content of saturated, monounsaturated, and polyunsaturated fatty acids, and essential fatty acids. For most species, I found saturated fatty acid content decreased with increasing temperature, while polyunsaturated fatty acid content and essential fatty acid content increased with increasing temperature. My thesis provides insights into the effects of climate warming on pasture ecosystems.


Animals ◽  
2020 ◽  
Vol 10 (5) ◽  
pp. 778
Author(s):  
Piotr Skałecki ◽  
Agnieszka Kaliniak-Dziura ◽  
Piotr Domaradzki ◽  
Mariusz Florek ◽  
Monika Kępka

The aim of the study was to compare the fatty acid profile and content and the oxidative stability of the lipid fraction of Prussian Carp (Carassius gibelio) fillets with and without skin. Carp specimens were obtained in spring from a fish farm located in the Lublin Voivodeship. The research material consisted of skin-on (n = 12) and skinless (n = 12) fillets (hand-filleted). Their chemical composition (water, ash, protein, and fat content), calorific value, and nutritional quality index (NQI) were analysed, as well as their fatty acid content and profile. The oxidative stability of the lipids was assessed on the basis of the peroxide value (PV), thiobarbituric acid reactive substances (TBARS) value, and the content of the conjugated dienes and trienes (CD and CT), while determination of the degree of fat hydrolysis was based on the acid value (AV) and free fatty acids (FFA). The Carp fillet with skin contained significantly (p ≤ 0.01) more fat (by 2.69 pp) and calories (by 92.16 kJ∙100 g−1) than the skinless fillet, and over three times as much n-3 polyunsaturated fatty acids (n-3 PUFA), including eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids. In the skin-on fillet, the lipid oxidation and hydrolysis parameters were significantly higher, but did not deviate from the values specified for fresh fish and/or fish fit for consumption.


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