Preparation and Characterization of Human Milk Fat Substitutes Based on Triacylglycerol Profiles

Human milk fat substitutes (HMFS) having similarity in (TAG) composition to human milk fat (HMF) were prepared by Lipozyme RM IM‐catalyzed interesterification of lard blending with selected oils in a packed bed reactor. Four oil blends with high similarity in fatty acid profiles to HMF were first obtained based on the blending model and then the blending ratios were screened based on TAG composition similarity by enzymatic interesterification in a batch reactor. The optimal ratio was determined as lard:sunflower oil:canola oil:palm kernel oil:palm oil:algal oil:microbial oil = 1.00:0.10:0.50:0.13:0.12:0.02:0.02. This blending ratio was used for a packed bed reactor and the conditions were then optimized as residence time, 1.5 h; reaction temperature, 50 °C. Under these conditions, the obtained product showed high degrees of similarity in fatty acid profile with 39.2 % palmitic acid at the sn‐2 position, 0.5 % arachidonic acid (n‐6) and 0.3 % docosahexaenoic acid (n‐3) and the scores for the degree of similarity in TAG composition was increased from 58.4 (the oil blend) to 72.3 (the final product). The packed bed reactor could be operated for 7 days without significant decrease in activity. The final product presented similar melting and crystallization profiles to those of HMF. However, due to the loss of tocopherols during deacidification process, the oxidative stability was lower than that of the oil blend. This process for the preparation of HMFS from lard with high similarity in TAG composition by physical blending and enzymatic interesterification, as optimized by mathematical models in a packed bed reactor, has a great potential for industrialization.     

Interesterification of Lard and Soybean Oil Blends Catalyzed by Immobilized Lipase in a Continuous Packed Bed Reactor

Structured lipids (SL), formulated by blends of lard and soybean oil in different ratios, were subjected to continuous enzymatic interesterification catalyzed by an immobilized lipase from Thermomyces lanuginosus (Lipozyme TL IM) in a continuous packed bed reactor. The original and interesterified blends were examined for fatty acid and triacylglycerol composition, regiospecific distribution, and solid fat content. Blends of lard and soybean oil in the proportions 80:20 and 70:30 (w/w), respectively, demonstrated a fatty acid composition, and proportions of polyunsaturated/saturated fatty acids (PUFA/SFA) and monounsaturated/polyunsaturated fatty acids (MUFA/PUFA), that are appropriate for the formulation of pediatric products. These same blends were suited for this purpose after interesterification because their sn-2 positions were occupied by saturated fatty acids (52.5 and 45.4%, respectively), while unsaturated fatty acids predominantly occupied sn-1,3 positions, akin to human milk fat. Interesterification caused rearrangement of triacylglycerol species.     

Interesterification of edible oils

Types of interesterification discussed are (a) interchange between a fat and free fatty acids, in which the most important reaction is the introduction of acids of low mol wt into a fat with higher fatty acids; (b) interchange between a fat and an alcohol, e.g., with glycerol, in order to produce emulsifiers like monoglycerides; (c) rearrangement of fatty acid radicals in triglycerides, the so-called transesterification which in recent years has taken on the same importance as hydrogenation or fractionation. In natural fats, the fatty acid radicals are not usually randomly distributed but become so by rearrangement; the distinctive physical properties of natural fats and oils can be changed within limits by this transesterification. Well-known examples are cocoa butter, palm oil, and lard. More important is the transesterification of a mixture of different fats and oils; e.g., the combination of hydrogenation and interesterification allows the production of a solid fat with high linoleic acid content. The composition of glycerides after random interesterification can be calculated by formulas. Distinct from random is such directed interesterification. This is done by working at low temperatures that glycerides with higher melting point crystallize from the reaction mixture. Directed interesterification can be combined with fractionation, for instance, to get a higher yield of liquid fraction from palm oil than is obtained by fractionation alone. The transesterification process can be performed in a batch or continuously. A small amount of metallic sodium or sodium ethylate is used as catalyst, which is destroyed by water or acid and removed after the reaction.     

Effect of Conjugated Linoleic Acid and Fatty Acid Positional Distribution on Physicochemical Properties of Structured Lipids

Specific structured lipids (SSL), previously produced by enzymatic acidolysis of coconut oil with different levels of conjugated linoleic acid (CLA) as fatty acid (FA), using a sn-1, 3 specific immobilized lipase, were used to prepare randomized structured lipids (RSL). A fraction of each SSL was subjected to chemical interesterification with sodium methoxide catalyst in order to modify the FA positional distribution and produce the corresponding RSL. Both families of structured lipids (SL) containing CLA were physicochemically characterized. Then, analysis of variance (ANOVA) was performed to evaluate the effects of CLA content (10, 20, 30 and 40%) and FA positional distribution (specific and randomized) on physicochemical properties of SL. Free fatty acids (FFA), peroxide value (PV) and p-anisidine value (p-AV) were not significantly affected by either CLA content or distribution. As expected, the iodine value (IV) and saponification value (SV) were influenced by CLA content but not by FA positional distribution, while oxidative stability index (OSI) was affected by both factors. Dropping point (DP), cloud point (CP) and solid fat content (SFC) decreased with the increase of CLA, while viscosity increased with the level of CLA. The FA positional distribution affected practically all the evaluated physical properties of SL, except CP and DP.     

The influence of chemical interesterification on the physicochemical properties of complex fat systems. 3. Rheology and fractality of the crystal network

Chemically interesterified and noninteresterified lard-canola oil (LCO) and palm oil-soybean oil blends ranging from 100% hardstock to 50%:50% hardstock/vegetable oil (w/w) were evaluated for hardness index (HI) using cone penetrometry and viscoelastic properties, such as shear storage modulus G′, using controlled-stress rheometry. The HI and G′ of palm oil decreased upon addition of soybean oil, and chemical interesterification did not affect the HI or G′ of palm oil or palm oil-soybean oil blends. The HI and G′ of lard decreased upon addition of canola oil, while chemical interesterification led to increases in both the HI and G′ of lard and LCO blends. All these effects were nonsolid fat content-related, since solid fat content did not change substantially upon chemical interesterification. The microstructure of the fat crystal network in lard and palm oil was quantified rheologically using fractal analysis. Chemical interesterification did not affect the fractal dimension of the fat crystal networks in palm oil or lard (2.82 and 2.88, respectively). The rheological properties of the macroscopic systems were not affected by the spatial distribution of mass within their fat crystal networks. Moreover, our results suggest that the increases in G′ observed in lard upon chemical interesterification are potentially due to changes in the properties of the particles which make up the network (crystal habit).     

胡萝卜片真空油炸过程用油品质研究

主要探讨了真空油炸胡萝卜片后三种炸用油的稳定性，研究了三种炸用油的酸价、过氧化值、羰基价随油炸时间的变化规律，分析了它们之间的相关性。结果显示：与大豆色拉油相比，棕榈油和猪油有更高的油炸稳定性；三种油的酸价、过氧化值、羰基价与油炸时间存在着显著的相关性。     

Preparation of Human Milk Fat Substitutes from Lard by Lipase‐Catalyzed Interesterification Based on Triacylglycerol profiles

Human milk fat substitutes (HMFSs) with triacylglycerol profiles highly similar to those of human milk fat (HMF) were prepared from lard by physical blending followed by enzymatic interesterification. Based on the fatty acid profiles of HMF, different vegetable and single‐cell oils were selected and added to the lard. Blend ratios were calculated based on established physical blending models. The blended oils were then enzymatically interesterified using a 1,3‐regiospecific lipase, Lipozyme RM IM (RML from Rhizomucor miehei immobilized on Duolite ES562; Novozymes A/S, Bagsværd, Denmark), to approximate HMF triacylglycerol (TAG) profiles, particularly with respect to the distribution of palmitic acid in the sn?2 position. The optimized blending ratios were determined to be: lard:sunflower oil:canola oil:palm kernel oil:palm oil:algal oil:microbial oil = 1.00:0.10:0.50:0.13:0.12:0.02:0.02. The optimized reaction conditions were determined to be: enzyme load of 11 wt%, temperature of 60 °C, water content of 3.5 wt%, and reaction time of 3 hours. The resulting product was evaluated for total and sn?2 fatty acids, polyunsaturated fatty acids, and TAG composition. A high degree of similarity was obtained, indicating the great potential of the product as a fat alternative for use in infant formulas.     

Influence of lipase-catalyzed interesterification on the oxidative stability of melon seed oil triacylglycerols

Melon seeds are rich in oil. However, the stability of melon seed oil (MSO) is low because of its high content of the essential fatty acid, linoleic acid (18:2n-6). MSO was physically blended or enzymatically interesterified with higholeic sunflower oil (HOSO). The fatty acid composition of MSO was remarkably changed after interesterification. Palmitic (16:0), stearic (18:0), and oleic (18:1n-9) acid contents increased at the sn-2 position of triacylglycerols, whereas 18:2n-6 decreased due to interesterification. The oxidative stability of the physical and Pseudomonas sp. (PS30) lipase-interesterified blends was assessed with the Oxidative Stability Instrument, peroxide value, and conjugated diene methods. The stability of MSO increased with increased proportions of HOSO, which was the source of 18:1n-9 in the blends. The ratio of 18:1n-9/18:2n-6 improved from 0.18 in MSO to 1.47 in the enzymatically interesterified blend. Calculated oxidizability and the results of oxidation tests of the blends confirmed the improvement in MSO stability by both physical blending and enzymatic interesterification.     

Influence of lipase-catalyzed interesterification on the oxidative stability of melon seed oil triacylglycerols

Melon seeds are rich in oil. However, the stability of melon seed oil (MSO) is low because of its high content of the essential fatty acid, linoleic acid (18:2n-6). MSO was physically blended or enzymatically interesterified with higholeic sunflower oil (HOSO). The fatty acid composition of MSO was remarkably changed after interesterification. Palmitic (16:0), stearic (18:0), and oleic (18:1n-9) acid contents increased at the sn-2 position of triacylglycerols, whereas 18:2n-6 decreased due to interesterification. The oxidative stability of the physical and Pseudomonas sp. (PS30) lipase-interesterified blends was assessed with the Oxidative Stability Instrument, peroxide value, and conjugated diene methods. The stability of MSO increased with increased proportions of HOSO, which was the source of 18:1n-9 in the blends. The ratio of 18:1n-9/18:2n-6 improved from 0.18 in MSO to 1.47 in the enzymatically interesterified blend. Calculated oxidizability and the results of oxidation tests of the blends confirmed the improvement in MSO stability by both physical blending and enzymatic interesterification.     

Detection of lard and randomized lard as adulterants in refined-bleached-deodorized palm oil by differential scanning calorimetry

A study was conducted to assess the use of differential scanning calorimetry (DSC) for detecting the presence of lard/randomized lard as adulterants in refined-bleached-deodorized (RBD) palm oil. Lard extracted from the adipose tissues of pig was chemically interesterified using sodium methoxide as catalyst. DSC thermal profiles of both genuine lard and randomized lard were compared with those of other common animal fats such as beef tallow, mutton tallow, and chicken fat. Lard and randomized lard were then blended with RBD palm oil in two series, in proportions ranging from 0.2 to 20%, and DSC analyses were obtained. The DSC cooling profiles of adulterated RBD palm oil samples showed an adulteration peak corresponding to lard/randomized lard in the low-temperature region. This peak was confirmed as an indicator of the presence of lard in RBD palm oil since similar experiments carried out using other common animal fats such as mutton tallow, beef tallow, and chicken fat showed that the lard adulteration peak could be distinctly identified. Using this method, a detection limit of 1% lard/randomized lard was reached (P<0.0001).     

Interesterification of Soybean Oil and Methyl Stearate Catalyzed by Guanidine‐Functionalized SBA‐15 Silica

The main purpose of this study was to develop a heterogeneous interesterification catalyst for the modification of edible oils to enhance their physicochemical and functional performances. To achieve this, 1,3‐dicyclohexyl‐2‐octylguanidine was covalently immobilized on the SBA‐15 (Santa Barbara Amorphous 15) material and then used as solid catalysts for the interesterification between soybean oil and methyl stearate. The characterization of the guanidine‐functionalized SBA‐15 material included Fourier transform infrared spectra, scanning electron microscopy, elemental analysis, and nitrogen adsorption–desorption techniques. It was shown that the solid base catalyst could efficiently catalyze the interesterification reaction. After the interesterification, the fatty acid profiles and triacylglycerol compositions of interesterified products were substantially varied. The influence of interesterification parameters, such as the substrate ratio, reaction time, reaction temperature and catalyst loading, on the interesterification reaction was investigated regarding the percentage of stearic acid in interesterified triacylglycerols. The stearic acid percentage of 27.9 % was achieved at 100 °C within 4 h when the methyl stearate/soybean oil molar ratio of 6:1 was employed. The catalyst could be recovered easily by filtration and reused without significant loss of activity.     

Synthesis of water‐reducible acrylic–alkyd resins based on modified palm oil

Water‐reducible acrylic–alkyd resins were synthesized from the reaction between monoglycerides prepared from modified palm oil and carboxy‐functional acrylic copolymer followed by neutralization of carboxyl groups with diethanolamine. Modified palm oil was produced by interesterification of palm oil with tung oil at a weight ratio of 1 : 1, using sodium hydroxide as a catalyst, whereas carboxy‐functional acrylic copolymer was prepared by radical copolymerization of n‐butyl methacrylate and maleic anhydride. The amount of acrylic copolymer used was from 15 to 40% by weight, and it was found that homogeneous resins was obtained when the copolymer content was 20–35 wt %. All of the prepared water‐reducible acrylic–alkyd resins were yellowish viscous liquids. Their films were dried by baking at 190°C and their properties were determined. These films showed excellent water and acid resistance and good alkali resistance. © 2005 Wiley Periodicals, Inc. J Appl Polym Sci 96: 1170–1175, 2005     

Stability of Interesterified Fats

Stability study carried out with interesterified (i) refined cottonseed oil (CSO), blends of (ii) vanaspati and refined groundnut oil (40:60 w/w) (vanaspati-GNO), (iii) refined and bleached sal (Shorea robusta) fat and refined groundnut oil (30:70) (Sal-GNO) and (iv) edible grade sheep tallow and refined groundnut oil (30:70) (ST-GNO) indicated that rearranged CSO and ST-GNO were more and sal-GNO less prone to oxidative rancidity compared to their corresponding starting stocks. Vanaspati-GNO was more or less similar to its starting stock. In other words, the process of interesterification had different effects on different starting stocks vis-à-vis oxidative rancidity. Addition of antioxidant (BHA) improved the stability of interesterified products to a large extent. Development of oxidative rancidity as measured by peroxide value in all the interesterified products during storage was faster than that observed with vanaspati. All the interesterified products were stable towards hydrolytic rancidity during storage. When the linoleic content of a blend was about 25%, the process of interesterification had no or marginal adverse effect on the development of oxidative rancidity. Higher linoleic acid (about 50%) made the stock more unstable as a result of interesterification. Comparatively more instability of interesterified blend containing sheep tallow cannot be explained on the basis of its linoleic acid content and its migration as a result of rearrangement.     

Physico‐chemical composition,fractionated glycerides and fatty acid profile of chicken skin fat

Skin is one of the several co‐products of chicken meat industries, considered as waste, being rarely utilized or underutilized. Brazil is the world leader in chicken exports (3.6 million tons) and the third largest producer with 10.9 million tons, from which 440 000 ton/year are residues. This work aimes at characterizing chicken skin fat (CSF), comparing it with soybean oil, a well‐known and abundant compound, evaluating the physico‐chemical composition, fractionated glycerides and fatty acid profile, searching for CSF use in interesterification reactions. For that, determination of peroxide and p‐anisidine values, as well as thiobarbituric acid, iodine, saponification, acidity, unsaponified matter and refraction indexes were accomplished, besides the glycerides fractionation, followed by FAME derivatization and identification by GC. The nutritional quality indexes were calculated from the lipid profile. CSF showed satisfactory quality due to low acidity (0.65 g oleic acid/100 g), peroxide (2.14 meq/kg), p‐anisidine (0.70 absorbance units/g) values, besides presenting high proportion of MUFA (40%). However, due to CSF low hypocholesterolemic/hypercholesterolemic value (HH = 2.72), it may be difficult to use it for nutritional purposes the way it is found, once it tends to increase cholesterol. CSF it is a promising residue for different purposes including interesterification reactions and biodiesel production.     

Epoxidation of karanja (Pongamia glabra) oil catalysed by acidic ion exchange resin

Karanja oil with an iodine value of 89 g/100 g was epoxidised in situ with aqueous hydrogen peroxide and acetic acid in the presence of Amberlite IR‐120 acidic ion exchange resin as catalyst. The effect of the operating variables on the oxirane oxygen content, as well as on the oxirane ring stability and the iodine value of the epoxidised karanja oil, were determined. The variables studied were stirring speed, hydrogen peroxide‐to‐ethylenic unsaturation molar ratio, acetic acid‐to‐ethylenic unsaturation molar ratio, temperature, and catalyst loading. The effects of these parameters on the conversion to the epoxidised oil were studied and the optimum conditions for the maximum oxirane content were established. The proposed kinetic model takes into consideration the two side reactions, namely, epoxy ring opening involving the formation of hydroxy acetate and hydroxyl groups, and the reaction between the peroxyacid and the epoxy group. The kinetic and adsorption constants of the rate equations were estimated by the best fit using Marquardt's algorithm. Good agreement between experimental and predicted data validates the proposed kinetic model. From the estimated kinetic constants, the apparent activation energy for the epoxidation reaction was found to be 11 kcal/mol.     

Trans‐free fats through interesterification of canola oil/palm olein or fully hydrogenated soybean oil blends

Binary blends of canola oil (CO) and palm olein (POo) or fully hydrogenated soybean oil (FHSBO) were interesterified using commercial lipase, Lypozyme TL IM, or sodium methoxide. Free fatty acids (FFA) and soap content increased and peroxide value (PV) decreased after enzymatic or chemical interesterification. No difference was observed between the PV of enzymatically and chemically interesterified blends. Enzymatically interesterified fats contained higher FFA and lower soap content than chemically prepared fats. Slip melting point (SMP) and solid‐fat content (SFC) of CO and POo blends increased, whereas those of CO and FHSBO blends decreased after chemical or enzymatic interesterification. Enzymatically interesterified CO and POo blends had lower SMP and SFC (at some temperatures) than chemically interesterified blends. The status was reverse when comparing chemically and enzymatically interesterified CO and FHSBO blends. The induction period for oxidation at 120°C of blends decreased after interesterification. However, chemically interesterified blends were more oxidatively stable than enzymatically interesterified blends. Interesterified blends of CO and POo or FHSBO displayed characteristics suited to application as trans‐free soft tub, stick, roll‐in and baker's margarine, cake shortening and vanaspati fat.     

Chemical Properties of Virgin Coconut Oil

A study on the commercial virgin coconut oil (VCO) available in the Malaysian and Indonesian market was conducted. The paper reported the chemical characteristics and fatty acid composition of VCO. There was no significant difference in lauric acid content (46.64–48.03%) among VCO samples. The major triacylglycerols obtained for the oils were LaLaLa, LaLaM, CLaLa, LaMM and CCLa (La, lauric; C, capric; M, myristic). Iodine value ranged from 4.47 to 8.55, indicative of only few unsaturated bond presence. Saponification value ranged from 250.07 to 260.67 mg KOH/g oil. The low peroxide value (0.21–0.57 mequiv oxygen/kg) signified its high oxidative stability, while anisidine value ranged from 0.16 to 0.19. Free fatty acid content of 0.15–0.25 was fairly low, showing that VCO samples were of good quality. All chemical compositions were within the limit of Codex standard for edible coconut oil. Total phenolic contents of VCO samples (7.78–29.18 mg GAE/100 g oil) were significantly higher than refined, bleached and deodorized (RBD) coconut oil (6.14 mg GAE/100 g oil). These results suggest that VCO is as good as RBD coconut oil in chemical properties with the added benefit of being higher in phenolic content.     

Chemical Properties and Fatty Acid Composition of Thunbergia fragrans Roxb. Seed Oil

The physicochemical and fatty acid compositions of seed oil extracted from Thunbergia fragrans were determined. The oil content, free fatty acids, peroxide value, saponification value and iodine value were 21.70 %, 2.25 % (as oleic acid), 9.6 (mequiv. O₂/kg), 191.71 (mg KOH/g) and 127.84 (g/100 g oil) respectively. The fatty acid profiles of the methyl esters showed the presence of 90.16 % unsaturated fatty acids and 9.84 % saturated fatty acids. Palmitoleic acid, which is usually found in marine foods and is unique in seed oils of botanical origin, was the major component (79.24 %). The oil can also be used in industries for the preparation of liquid soaps, shampoos and alkyd resin.     

橡籽油的酸催化水解工艺研究

以橡籽油为原料进行常压一次酸催化水解反应。研究了反应温度、反应时间、催化剂用量、油水比和乳化剂用量对水解反应的影响,得出橡籽油水解的最优条件:反应温度为95℃,反应时间为9 h,催化剂浓硫酸用量为10%,油水比为1∶2,乳化剂十二烷基磺酸钠用量为1%,此时橡籽油的水解产物酸值为189.41mg KOH/g,水解率为94.71%。     

Physicochemical Properties and Fatty Acid Profile of Phoenix Tree Seed and its Oil

Various components of Phoenix tree (Firmiana simplex) seed were determined. Oil, protein, moisture, ash, and fiber accounted for 27.8 ± 0.3, 19.7 ± 0.4, 7.5 ± 0.2, 4.4 ± 0.3, and 31.23 ± 0.93 % (w/w) of the seed, respectively. The acid value, peroxide value, saponification value, and unsaponifiable matter content of Phoenix tree seed oil extracted using the Soxhlet method were 3.73 ± 0.02 mg KOH/g, 1.97 ± 0.21 mmol/kg, 183.74 ± 2.37 mg KOH/g, and 0.90 ± 0.05 g/100 g, respectively. The total tocopherol content was 54.5 ± 0.5 mg/100 g oil, which consisted mainly of δ‐tocopherol (29.5 ± 0.6 mg/100 g oil) and γ‐tocopherol (13.8 ± 0.8 mg/100 g oil). Linoleic acid (L, 30.2 %), oleic acid (O, 22.2 %), and sterculic acid (S, 23.2 %) were the main unsaturated fatty acids of Phoenix tree seed oil. The saturated fatty acids included palmitic acid (17.4 %) and stearic acid (St, 2.9 %). The work shows the first report of sterculic acid in seeds of this species. This oil can be used as a raw material to produce sterculic acid.