Lipase‐catalyzed synthesis of structured lipids with fatty acids fractionated from saponified chicken fat and menhaden oil

In this study, free fatty acids (FFA) of chicken fat and menhaden oil, which were obtained by saponification, were dry‐fractionated and solvent fractionated. Using these fractionation processes, FFA fractions enriched in monounsaturated (MUFA) and polyunsaturated fatty acids were obtained. Chicken fat FFA fractions enriched in MUFA were modified further by lipase‐catalyzed esterification with the starting fat to produce structured lipids of high MUFA content.     

Analysis of fatty acid profile in plasma phospholipids by solid‐phase extraction in combination with GC

Phospholipids are recognised as an important source and transport form for metabolically active fatty acids. Therefore, detailed analysis of fatty acid profiles in plasma phospholipids as marker for dietary habits or interventions gains more and more importance. Appropriate analytical methods described so far are either expensive or susceptible to handling errors. We developed a method to separate plasma phospholipids by acetone fractionation combined with SPE in order to analyse the fatty acid compositions in phospholipid fractions of human plasma by GC analysis. The method has been validated in order to be applied to the routinely performed analysis of the samples of patients who will be participating in a dietary supplement study. The method presented here was successfully validated and is stable, efficient and reproducible. It can be used in a routine fashion to deliver the fatty acid profile [palmitic acid (16:0), heptadecanoic acid (17:0), stearic acid (18:0), oleic acid (18:1n‐9), linoleic acid (18:2n‐6), linolenic acid (18:3n‐3), arachidonic acid (20:4n‐6), eicosapentaenoic acid (20:5n‐3) and docosahexaenoic acid (22:6n‐3)] in plasma phospholipid samples. Using a sample volume of 500 µL, recovery of plasma phospholipids is 92 ± 11%; LOQ is 2.2 µg fatty acid/mL. A set of samples from cancer patients and healthy individuals was analysed and confirmed the applicability of the described method.     

Effect of lecithins partly replacing rumen‐protected fat on fatty acid digestion and composition of cow milk

The effects on fatty acid digestibility and milk fat composition of calcium soaps of palm oil fatty acids and of a 25% replacement of the Ca soaps by four different lecithins (raw, deoiled and deoiled/partially hydrolysed soy lecithin, raw canola lecithin) and soybean oil were investigated in six lactating cows each. The complete diets contained the lipid supplements at proportions of 30 g fatty acids/kg dry matter. Partial replacement of Ca soaps by soy or canola lecithins and soybean oil had small but significant effects on fatty acid digestion and utilisation, as well as the fatty acid profile in milk. Relative to Ca soaps alone, C 16:0 digestibility was slightly higher with lecithins, and percentage of conjugated linoleic acid and trans C 18:1 in milk fat increased while proportion of C 16:0 decreased. Deoiling of lecithins slightly reduced the effects on C 16:0 digestibility and excretion with milk. The influence of lecithin processing was higher than the differences between raw soy and raw canola lecithin. Nevertheless, most of the few effects observed may be related to the fatty acids supplied with the lecithins but, regarding C 18:1 trans‐11 and odd chain fatty acids, there is some evidence that lecithins impair rumen microbial activity less than soybean oil.     

Multivariate fatty acid and fatty alcohol profile of mullet bottarga

Mullet bottarga is a food delicacy obtained by salting and drying the intact roes of mullet (Mugil spp.). The fatty acid and fatty alcohol compositions of different samples of bottarga were studied by means of gas chromatography (GC) and multivariate analysis (MVA). High percentages of beneficial n‐3 PUFA, among which docosahexaenoic acid (DHA) (22:6n‐3, 11.9%) and eicosapentaenoic acid (EPA) (20:5n‐3, 8.6%), were detected. Differences in the concentrations of unsaturated FA and FAL were observed among samples, while saturated components showed little variations. On the other hand, the total contents of saturated, monounsaturated and polyunsaturated components were similar. The principal component analysis loadings bi‐plot showed that n‐6 PUFA concentrations were inversely correlated to those of n‐3 PUFA, except for DHA that showed no correlations. Correlations between FAL concentrations were also observed. Furthermore, integrating our GC data with those from the literature on mullet and tuna bottarga, the MVA showed that both bottarga typologies exhibit a similar trend in the FA distribution and that 16:0 and 16:1n‐7 FA are the variables with the highest discriminant power. In this work, we demonstrated the usefulness of the application of MVA to GC data to extract meaningful information otherwise hidden in the amount of data.     

Comparison of poly(o‐anisidine) and poly(o‐anisidine‐co‐aniline) copolymer synthesized by chemical oxidative method

In this study, poly(o‐anisidine) [POA], poly(o‐anisidine‐co‐aniline) [POA‐co‐A], and polyaniline [PANi] were chemically synthesized using a single polymerization process with aniline and o‐anisidine as the respective monomers. During the polymerization process, p‐toluene sulfonic acid monohydrate was used as a dopant while ammonium persulfate was used as an oxidant. N‐methyl‐pyrolidone (NMP) was used as a solvent. We observed that the ATR spectra of POA‐co‐A showed features similar to those of PANi and POA as well as additional ones. POA‐co‐A also achieved broader and more extended UV–vis absorption than POA but less than PANi. The chemical and electronic structure of the product of polymerization was studied using Attenuated Total Reflectance spectroscopy (ATR) and UV–visible spectroscopy (UV–vis). The transition temperature of the homopolymers and copolymers was studied using differential scanning calorimetry and the viscosity average molecular weight was studied by using dilute solution viscometry. © 2010 Wiley Periodicals, Inc. J Appl Polym Sci, 2010     

The fatty acid composition of small and large naturally occurring milk fat globules

Native milk fat globules of various mean diameters, ranging from d₄₃ = 1.5 to 7.3 μm, were obtained using microfiltration of raw whole milk acquired in winter and spring. After total lipid extraction, fatty acid composition was characterized by methyl and butyl ester analysis using gas chromatography. The oleic and linoleic acid content of milk obtained in winter increased with fat globule size, whereas myristic and palmitic acid decreased. There was significantly more lauric, myristic and palmitoleic acid, and less stearic acid in small fat globules compared to large fat globules in milk obtained in both winter and spring. The relative content of oleic and linoleic acids were found to depend on fat globule size and season. Results are interpreted on the basis of the relative content of milk fat globule membrane depending on fat globule size, and on consequences of compositional variations on milk fat globule melting behavior.     

Enzyme-assisted extraction of chicken skin protein hydrolysates and fat: Degree of hydrolysis affects the physicochemical and functional properties

Enzyme-assisted extraction (EAE) of oils/fats involves the disruption of the cell wall of source material using enzymes to facilitate the release of oil. When proteases are used as the enzyme, EAE ends in the extracted oil as well as the protein hydrolysates. Herein, the EAE (using a commercial protease, Alcalase) was exploited to obtain fat and protein hydrolysates from chicken skin. Degree of hydrolysis (DH, the percentage ratio of cleaved peptide bonds), which showed a logarithmic correlation with the reaction time, was found to affect the properties of the products. As the DH increased, the peptide chain length of protein hydrolysates decreased which was confirmed by SDS-PAGE analysis. With the increase of DH, the emulsifying activity index, foaming capacity, and oil holding capacity of the hydrolysates decreased but the solubility and emulsion stability index increased (p < 0.05). The DPPH free radical scavenging activity of the hydrolysates increased with the DH up to DH = 39.62% but decreased thereafter (p < 0.05). EAE resulted in a rise in fat yield and the fat contained a higher amount of unsaponifiables and lower free fatty acids (FFA) content, as compared to the control treatment (No enzyme, 80°C, 2 h, p < 0.05). DH affected the fat yield and the unsaponifiables content of the fat, positively (p < 0.05). However, it did not affect the fat FFA content and iodine value (p > 0.05). Results obtained here showed DH can be used as an effective measure for controlling the physicochemical and functional properties of chicken skin protein hydrolysates and fat in the EAE process.     

Differently sized native milk fat globules separated by microfiltration: fatty acid composition of the milk fat globule membrane and triglyceride core

The aim of this study was to characterize the fatty acid composition of the core and membrane of differently sized milk fat globules separated by microfiltration, which can now be used to manufacture dairy products. Native milk fat globules of various mean diameters, ranging from d₄₃ = 2.3 µm to 8.0 µm, were obtained using microfiltration of raw whole milk. After milk fat globule washing, the milk fat globule membrane (MFGM) and the triglyceride core (TC) were separated by manual churning. After total lipid extraction from each fraction, their fatty acid composition was characterized using methyl ester analysis by gas chromatography. Regardless of season, no significant differences were observed in the fatty acid composition of the MFGM phospholipids. Conversely, significant differences were found in the fatty acid composition of TC; particularly, small fat globule TC contained more medium‐chain fatty acids and less stearic acid than large fat globule TC. These results show that the previously observed differences in total fatty acid composition among differently sized milk fat globules are due to their triglyceride composition and MFGM amount rather than to the composition of the MFGM.     

Assessment of the effects of sex and harvesting season on lipid and fatty acid composition of Sparidae species

In the present study, the lipid amount and fatty acid profile of different Sparidae species, including gilthead seabream, juvenile gilthead seabream, annular seabream, white seabream, common two-banded seabream were evaluated. Fish were seasonally collected from Köyceğiz Lagoon (Muğla, South Western Turkey) from June 2018 to June 2019 and after collection, the sex of each specimen was recorded. According to the results of the study, the highest lipid amount was found in female annular seabream individuals as 8.09 ± 0.78% in November and the lowest lipid amount was found in male juvenile gilthead seabream as 0.98 ± 0.12% in March. Palmitic acid and oleic acid were determined as the most abundant SFA and MUFA for all species, respectively. The highest value of DHA, which was the predominant PUFA was assessed as 15.33 ± 0.26% in female white seabream in November whereas the lowest value (3.83 ± 0.36%) was found in gilthead seabream in December. The n-6/n-3 ratio was determined between 0.27 ± 0.00 (for male common two-banded seabream in July)-1.20 ± 0.03 (for male gilthead seabream in December) and it followed within the range of healthy values for all species. As a conclusion, it was found that values of lipid and fatty acid profiles among the examined Sparidae species vary among the season of collection. The results of the study gave the seasonal nutritional values of four economically-important Sparidae species that being rich in healthy polyunsaturated fatty acids such as DHA, have beneficial in human nutrition.     

Determination of the fatty acid profile by 1H‐NMR spectroscopy

The common unsaturated fatty acids present in many vegetable oils (oleic, linoleic and linolenic acids) can be quantitated by ¹H‐nuclear magnetic resonance spectroscopy (¹H‐NMR). A key feature is that the signals of the terminal methyl group of linolenic acid are shifted downfield from the corresponding signals in the other fatty acids, permitting their separate integration and quantitation of linolenic acid. Then, using the integration values of the signals of the allylic and bis‐allylic protons, oleic and linoleic acids can be quantitated. The procedure was verified for mixtures of triacylglycerols (vegetable oils) and methyl esters of oleic, linoleic and linolenic acids as well as palmitic and stearic acids. Generally, the NMR (400 MHz) results were in good agreement with gas chromatographic (GC) analyses. As the present ¹H‐NMR‐based procedure can be applied to neat vegetable oils, the preparation of derivatives for GC would be unnecessary. The present method is extended to quantitating saturated (palmitic and stearic) acids, although in this case the results deviate more strongly from actual values and GC analyses. Alternatives to the iodine value (allylic position equivalents and bis‐allylic position equivalents) can be derived directly from the integration values of the allylic and bis‐allylic protons.     

Muffins made with monoglyceride oleogels: Impact of fat replacement on sensory properties and fatty acid profile

Most shortenings used in baked products are solid fats high in saturated fatty acids that may also contain trans fatty acids, which are nutritionally unhealthy. Successful solid fat replacement requires maintaining not only the physicochemical properties, but also the sensory quality of the products. In this study, the sensory properties and lipid profile of muffins formulated with a previously optimized monoglyceride oleogel were compared with those of muffins made with a commercial margarine (Control). Untrained consumers (n = 130) evaluated the effect of the fat replacement on several sensory attributes using a 5-point hedonic scale. In comparison with the Control, the oleogel-based muffin (M_o) scored similarly for flavor and sponginess, but rated significantly higher for appearance and color. Based on overall quality score, consumers liked M_o more than the Control. The reformulated muffins had a significantly improved lipid profile, with a 68% reduction in saturated fats and an almost 4-fold increase in monounsaturated fats. This study supports the use of monoglyceride oleogels as full-fat substitutes to develop healthier bakery products, maintaining or improving consumer acceptance. It is expected that the promising results presented here will help the food industry to accelerate the transition from conventional solid fats to oleogels.     

Thermal decomposition kinetics of thermotropic copolyesters made from trans‐p‐hydroxycinnamic acid and p‐hydroxybenzoic acid

A series of thermotropic copolyesters were synthesized by direct thermal melt polycondensation of p‐acetoxybenzoic acid (PHB) with trans‐p‐acetoxycinnamic acid (PHC). The dynamic thermogravimetric kinetics of the copolyesters in nitrogen were analyzed by four single heating‐rate techniques and three multiple heating‐rate techniques. The effects of the heating rate, copolyester composition, degradation stage, and the calculating techniques on the thermostability and degradation kinetic parameters of the copolyesters are systematically discussed. The four single heating‐rate techniques used in this work include Friedman, Freeman–Carroll, Chang, and the second Kissinger techniques, whereas the three multiple heating‐rate techniques are the first Kissinger, Kim–Park, and Flynn–Wall techniques. The decomposition temperature of the copolyesters increases monotonically with increasing PHB content from 40 to 60 mol %, whereas their activation energy exhibits a maximal value at the PHB content of 50 mol %. The decomposition temperature, activation energy, the order, and the frequency factor of the degradation reaction for the thermotropic copolyester with PHB/PHC feed ratio of 50/50 mol % were determined to be 374°C, 408 kJ/mol, 7.2, and 1.25 × 10²⁹ min^?1, respectively. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 91: 445–454, 2004     

Physico‐chemical parameters for the characterization of pure beeswax and detection of adulterations

Pure beeswaxes produced in different climatic regions of Spain have been characterized by the determination of nine physico‐chemical parameters: density, acid, saponification, ester, ratio number, iodine, peroxide, melting point and ash content values. The official methods of analysis to determine density and saponification values in fats and oils were not suitable for beeswaxes; alternative methods are proposed in this work for both parameters. After verifying the precision of the methods and the value guidelines, the usefulness of the physico‐chemical parameters to detect adulterations with paraffin, stearic acid, carnauba wax and tallow was tested: adulteration percentages of 5%, or higher, were commonly detected. Marketed foundation beeswax sheets, rejected or badly accepted by the bees, were also analyzed to discuss their quality; 25 out of 27 beeswax sheets show anomalous values for at least one parameter.     

Modelling lipase‐catalysed transesterification of fats containing n‐3 fatty acids monitored by their solid fat content

Transesterification of fat blends rich in n‐3 polyunsaturated fatty acids (n‐3 PUFA), catalysed by a commercial immobilised thermostable lipase from Thermomyces lanuginosa, was carried out batch‐wise. Experiments were performed, following central composite rotatable designs (CCRDs) as a function of reaction time, temperature and media formulation. Mixtures of palm stearin, palm kernel oil and a commercial concentrate of triacylglycerols rich in n‐3 PUFA (“EPAX 2050TG” in CCRD‐1 and “EPAX 4510TG” in CCRD‐2) were used. The time‐course of transesterification was indirectly followed by the solid fat content (SFC) values of the blend at 10 °C, 20 °C, 30 °C and 35 °C. A decrease in all SFC values of the blends at 10 °C, 20 °C, 30 °C and 35°C was observed upon transesterification. The SFC_{10 °C} and SFC_{20 °C} of transesterified blends varied between 18 and 48 and SFC_{35 °C} between 6 and 24. These values fulfil the technological requirements for the production of margarines. Under our conditions, lipid oxidation may be neglected. However, the accumulation up to 8.3% free fatty acids in reaction media is a problem to overcome. The development of response surface models, describing both the final SFC value and the SFC decrease, will allow predicting results for novel proportions of fats and oils and/or a novel combination time‐temperature.     

Effect of TAG composition on the solid fat content profile,microstructure, and hardness of model fat blends with identical saturated fatty acid content

TAGs play an important role in determining the functional properties of fat‐based food products such as margarines, chocolate, and spreads. Nowadays, special attention is given to the role of the TAG structure and how it affects functional properties such as mouth feel, texture, and plasticity. Key to this research is the need to develop more healthy fats with a reduced level of trans and saturated fatty acids (SFAs), while maintaining the desired properties. In this study, fat blends with identical levels of SFA (50%) but differing in the ratio asymmetric/symmetric blends were evaluated by pulsed NMR and texturometry as a function of storage time and storage temperature. A higher trisaturated TAG content gave rise to a higher solid fat content (SFC) at higher temperature and a lower SFC at lower temperature for both palmitic and stearic based blends. On the other hand, the effect of symmetry on the SFC‐profile of the blends was only clear for the stearic based blends. At lower temperatures, the SFC of symmetric TAG based blend (blend SM) was markedly lower than that of asymmetric TAG based blend (blend iS). However, from 30°C onwards, the SFC of blend SM was clearly higher than that of blend iS. The microscopic analyses revealed a denser crystal network for a higher degree of trisaturated TAG and for symmetric stearic based blends. Moreover, some blends showed a clear evolution of the microstructure during storage with smaller crystals transforming into larger ones. Finally, texture analyses demonstrated the importance of the crystallization and storage temperature on the hardness of the blends.     

TAG composition and solid fat content of palm oil, sunflower oil, and palm kernel olein belends before and after chemical interesterification

Modification of the characteristics of palm oil (PO), sunflower oil, and plam kernel olein (PKOo) according to conventional three-component mixture designs was undertaken by a combination of blending and chemical interesterification (CIE) techniques. TAG composition and solid fat content (SFC) profile of the starting blends were analyzed and compared with those of the interesterified blends. Upon CIE, extensive rearrangement of FA among TAG was evident. Concentrations of several TAG were increased, some were decreased, and several new TAG were formed. The resulting changes in TAG profile were reflected in the SFC of the blends. The SFC values of the chemically interesterified blends, except binary blends of PO/PKOo, revealed that they were softer than their respective starting blends. SFC data also indicated that eutectic interaction occurred between PO and PKOo in the starting blends and that this interaction was diminished after CIE.