High-melting Triacylglycerols Research Articles

Functional and Quality Profile Evaluation of Butters, Spreadable Fats, and Shortenings Available from Czech Market.

The aim of this study was to assess the functional properties of butters, spreadable fats, and shortenings, collected from the Czech market, in correlation with their nutritional values declared by the producers. Various methods were applied to determine relevant parameters of the products. Using penetration tests, samples were characterized by specific textural attributes according to their composition and processing type, particularly for the presence of milk/vegetable fats. Using differential scanning calorimetry (DSC), thermal peaks corresponding to medium- and high-melting triacylglycerol fractions were detected in the ranges 15-16 °C and 31.5-34.5 °C, respectively. Rheological analysis revealed that the viscoelasticity of samples was related to frequency behavior of the fat structure, characterized by the dominance of elastic modulus (G') over viscous modulus (G″) up to the frequency of 10 Hz. This indicated good emulsion stability of the products in the region of linear viscoelasticity. For spreadable fats, the structure was resistant to phase separation in the whole frequency range under study (0.1-100 Hz). The results showed that the applied techniques can be successfully used to characterize the processing and compositional quality of butters and vegetable fats.

A Review on the Fundamentals of Palm Oil Fractionation: Processing Conditions and Seeding Agents

AbstractFractionation is a well‐established process adopted in the fats and oils industries. It involves the separation of low and high melting triacylglycerol under controlled cooling conditions into olein and stearin fractions with distinct chemical and physical properties. Amongst the other vegetable oils, palm oil is one of the most fractionated oils in the past few decades mainly attributed to its semisolid properties. The various fraction of palm oil allows it to be used in different types of food products such as margarine, frying oil, and cocoa butter substitute. In fractionation, proper control of the fractionation conditions is important to produce the fractions with desirable stearin and olein quality. The purpose of this paper is to critically review the fractionation conditions (crystallization temperature, agitation, cooling rate and crystallization time) that affect the yield and quality of the oil produced. Additionally, it also provides the latest updates on the influence of seeding agents (diacylglycerol, monoacylglycerol, hard fat, phytosterol, phospholipid, lecithin, essential oil, sugar, polyglycerol ester, and talc) used in fractionation. This article is useful to provide a fundamental understanding of fractionation to scientists from the industries or academia working in the fats and oils industries.Practical Applications: This paper provides an in‐depth understanding of fractionation particularly on the parameters of fractionation in influencing the quality and yield of the stearin and olein produced. It also for the first time presents the effect of addition of various seeding agents on palm oil fractionation which can help the industry to select the appropriate seeding agents to improve the currently employed fractionation process. Thus, it can act as a guideline for the industry to understand and select the appropriate fractionation conditions when developing a new product using this approach. The fractionation conditions discussed here can also be used as a reference when fractionating other types of fats and oils as most of them share a common background.

Structural characteristics of crystals formed in palm oil using sorbitan tristearate and sucrose stearate

ABSTRACTThe formation and stabilization of fat crystals in palm oil (PO) by the templating effects of sorbitan tristearate (STS) and sucrose stearate (S-370) were examined. We observed that the crystallization mechanism occurred via heterogeneous nucleation, which was induced by co-crystallization or seeding, after the addition of STS or S-370, respectively. Overall, both emulsifiers, STS and S-370, caused an increase in the hardness of PO, which was related to changes in the microstructure. In addition, the intensity of this effect was shown to be dependent on the emulsifiers concentration. In differential scanning calorimetry analysis, S-370 proved to be associated predominantly to the crystallization of high-melting triacylglycerols (TAGs), while STS showed to actuate the crystallization of high and low-melting TAGs. Moreover, the addition of STS improved the polymorphic stability of the PO, while the use of S-370 resulted in a soft texture at lower temperatures.

Effects of Shear and Cooling Rate on the Crystallization Behavior and Structure of Cocoa Butter: Shear Applied During the Early Stages of Nucleation

Here we investigated the effects of applied shear and temperature during the early stages of nucleation on the isothermal crystallization behavior and microstructure of cocoa butter (CB). Results showed that the composition of nucleating triacylglycerols (TAGs) as well as crystalline microstructure and polymorphism of CB were affected by mixing and temperature gradients while still in the molten state. The initial crystalline material isolated from CB after it had been subjected to shear had a similar TAG composition as native CB. However, in the absence of shear, high melting TAGs such as trisaturates (SSS) along with lower amounts of monounsaturated TAGs (SUS) were present, possibly due to fractionation. After subjecting CB to shear in its molten state, crystallization rates were faster due to the cocrystallization of different TAGs into a mixed crystal; however, the polymorphic transition into the more stable β-V form was found to be slower due to inherent complexity in TAG composition. Under static co...

Sonocrystallization of Interesterified Fats with 20 and 30% of Stearic Acid at the sn‐2 Position and Their Physical Blends

AbstractPhysical blends (PB) of high oleic sunflower oil and tristearin with 20 and 30% stearic acid and their interesterified (IE) products where 20 and 30% of the fatty acids are stearic acid at the sn‐2 position crystallized without and with application of high intensity ultrasound (HIU). IE samples were crystallized at supercooling temperatures (ΔT) of 12, 9, 6, and 3 °C while PB were crystallized at ΔT = 12 °C. HIU induced crystallization in PB samples, but not in the IE ones. Induction in crystallization with HIU was also observed at ΔT = 6 and 3 °C for IE C18:0 20 and 30% and at ΔT = 9 °C only for the 30% samples. Smaller crystals were obtained in all sonicated samples. Melting profiles showed that HIU induced crystallization of low melting triacylglycerols (TAGs) and promoted co‐crystallization of low and high melting TAGs. In general, HIU significantly changed the viscosity, G′, and G″ of the IE 20% samples except at ΔT = 12 °C. While G′ and G″ of IE 30% did not increase significantly, the viscosity increased significantly at ΔT = 9, 6, and 3 °C from 1526 ± 880 to 6818 ± 901 Pa.s at ΔT = 3 °C. The improved physical properties of the sonicated IE can make them good contenders for trans‐fatty acids replacers.

Engineering the nucleation of edible fats using a high behenic acid stabilizer

A stabilizer high in behenic acid (HBS) was used to control nucleation of edible fats. The addition of HBS led to an enhanced nucleation of anhydrous milk fat (AMF) and palm oil (PO) which had lower levels of high melting triacylglycerols (HMTs) (melting point >30°C, relative to the temperature used to crystallize samples) compared to other fats. With the addition of 1.5% HBS, there was an increase in crystallization onset temperatures and density of the microstructure in these two fats. Further studies were conducted to investigate the interactions between HBS and specific homogeneous triacylglycerols (TAGs) or a mixture of triacylglycerols. HBS displayed solid‐state incompatibility (eutectic behavior) with tripalmitin and tristearin, whereas it displayed compatibility (monotectic partial solid solution formation) behavior when mixed with the high‐melting milk fat fraction (HMF). This suggests two mechanisms for nucleation enhancement of HBS. One mechanism would involve surface nucleation on top of pre‐formed TAG surfaces, for tripalmitin and tristearin, while the other mechanism would involve additionally co‐crystallization with the nucleating agent, for the case of milkfat's HMF.Practical application: HBS may be used to accelerate the nucleation of PO, AMF, and HMF. A slow crystallization behavior of PO often leads to post‐hardening problems and a long α‐lifetime. Thus, HBS has a potential to solve these issues. Our results showed that HBS is more effective on fats with relatively low amounts of HMTs (20–50%). In addition, the nucleation enhancing mechanism of HBS was more effective in a mixture of TAGs, rather than in pure TAGs.High behenic acid stabilizers (HBS) are used to stabilize fat‐structured and oil‐rich food products. It is shown that HBS interacts with high‐melting triacylglycerols (HMTs) present in the fats and oils to be stabilized and reduces their free energy of nucleation, as shown in the graphical abstract. This leads to the formation of large numbers of smaller, stabilizing crystals in the system. Moreover, it also shown that HBS interacts differently with different HMTs. It displays incompatibility with tristearin and tripalmitin but displays compatibility with the high melting fraction of milkfat. A greater molecular compatibility is postulated to lead to greater stabilization.

Characterization of Coconut Oil Fractions Obtained from Solvent Fractionation Using Acetone.

This work was aimed to study the solvent fraction of coconut oil (CNO). The fatty acid and triacylglycerol compositions, solid fat content (SFC) and the crystallization properties of CNO and its solid and liquid fractions obtained from fractionation at different conditions were investigated using various techniques. CNO was dissolved in acetone (1:1 w/v) and left to crystallize isothermally at 10°C for 0.5, 1 and 2 h and at 12°C for 2, 3 and 6 h. The solid fractions contained significantly lower contents of saturated fatty acids of ≤ 10 carbon atoms but considerably higher contents of saturated fatty acids with > 12 carbon atoms with respect to those of CNO and the liquid fractions. They also contained higher contents of high-melting triacylglycerol species with carbon number ≥ 38. Because of this, the DSC crystallization onset temperatures and the crystallization peak temperatures of the solid fractions were higher than CNO and the liquid fractions. The SFC values of the solid fractions were significantly higher than CNO at all measuring temperatures before reaching 0% just below the body temperature with the fraction obtained at 12°C for 2 h exhibiting the highest SFC. On the contrary, the SFC values of the liquid fractions were lower than CNO. The crystallization duration exhibited strong influence on the solid fractions. There was no effect on the crystal polymorphic structure possibly because CNO has β'-2 as a stable polymorph. The enhanced SFC of the solid fractions would allow them to find use in food applications where a specific melting temperature is desired such as sophisticated confectionery fats, and the decreased SFC of the liquid fractions would provide them with a higher cold stability which would be useful during extended storage time.

Characterization of the nanoscale structure of milk fat

The nanoscale structure of milk fat (MF) crystal networks is extensively described for the first time through the characterization of milk fat-crystalline nanoplatelets (MF-CNPs). Removing oil by washing with cold isobutanol and breaking-down crystal aggregates by controlled homogenization allowed for the extraction and visualization of individual MF-CNPs that are mainly composed of high melting triacylglycerols (TAGs). By image analysis, the length and width of MF-CNPs were measured (600nm×200nm–900nm×300nm). Using small-angle X-ray scattering (SAXS), crystalline domain size, (i.e., thickness of MF-CNPs), was determined (27nm (d001)). Through interpretation of ultra-small-angle X-ray scattering (USAXS) patterns of MF using Unified Fit and Guinier-Porod models, structural properties of MF-CNPs (smooth surfaces) and MF-CNP aggregations were characterized (RLCA aggregation of MF-CNPs to form larger structures that present diffused surfaces). Elucidation of MF-CNPs provides a new dimension of analysis for describing MF crystal networks and opens-up opportunities for modifying MF properties through nanoengineering.

효소적 반응을 이용한 비대칭형 1,2-Distearoyl-3-Oleoyl-rac-Glycerol 혼합물의 생성 및 융점 특성

본 연구는 대두극도경화유(fully hydrogenated soybean oil, FHSBO)와 oleic ethyl ester를 사용하여 코코아버터 대체유지(CBR)로서 사용가능한 비대칭 유지를 개발하고자 하였다. 생산된 비대칭 유지는 위치별 지방산 및 TAG 조성분석, 흡열 및 발열곡선 분석을 수행하여 특성연구를 진행하였으며, TAG 이성질체 분석과 solid fat index(SFI), slip melting point 측정 결과는 코코아버터와 비교 분석하였다. 위치별 지방산 및 TAG 조성 분석 결과, 최종적으로 생산된 비대칭 유지의 주요 TAG 조성은 SSO/SOS, PSO/POS로분석되었으며 sn-2 위치의 지방산은 62.5~68.4 area%의 범위로 주로 stearic acid로 구성되어 있음을 확인하였다. 이는 최종 생성물의 TAG 조성이 SOS, POS보다 주로 SSO, PSO와 같은 비대칭형 TAG로 구성되어 있음을 나타내는 결과인 것으로 생각된다. 또한 RP-HPLC/APCI-MS를 이용하여 SSO와 SOS의 TAG 이성질체 분석한 결과, [SS]+ : [SO]+의 비율이 0.54로 분석된 최종 생성물은 0.37로 분석된 코코아버터에 비하여 비대칭형 TAG인 SSO의 함량이 높으나, 대칭형 TAG인 SOS와 함께 공존하여 존재하는 것으로 나타났다. 코코아버터와 최종 생성물 모두 30~35°C의 온도 구간에서 급격한 흡열곡선을 나타내어 코코아버터 대체유지로서의 특성을 가지고 있었으나, 최종 생성물은 코코아버터보다 조금 높은 SFI와 slip melting point를 가지는 것으로 분석되었다. 이는 최종 생성물의 stearic acid 함량이 코코아버터보다 높은 것에 기인된 것으로 판단된다.

Effect of Temperature on the Crystalline Form and Fat Crystal Network of Two Model Palm Oil-Based Shortenings During Storage

Fat products experienced undesirable microstructural property changes due to the temperatures during transportation and storage. In this study, the lipid composition and solid fat content (SFC) of two model palm oil-based shortenings, which are denoted as shortening A (melting point of 35.1°C) and shortening B (melting point of 51.2°C), were evaluated, and their crystallization behavior and polymorphism during storage at various temperatures (−10 °C to 30 °C) was examined by X-ray diffraction (XRD) and polarized light microscopy (PLM). The fractal dimension (D b) was calculated to qualify the change in the crystal network during storage. The aggregation of high-melting triacylglycerols (TAGs) nanostructure and the formation of the most stable β polymorph were observed in shortening at higher temperatures (≥0 °C) during storage. At the same temperature, the intensity of β crystals in the two samples increased as the storage time increased, and this trend was obvious at high temperatures (≥10 °C). In addition, the intensity of the β crystals in the two samples gradually increased as the temperature increased, and the size of the crystalline particles became larger. The crystal size in shortening A was larger than that in shortening B at high temperatures (≥10 °C). The crystal network of shortening B was denser than that of shortening A. The D b value reached a maximum at 10 °C and 30 °C for shortening A and B, respectively. These findings have important implications on the storage stability and functional properties of palm oil-based shortenings.

Comparative Analysis of Lipid Composition and Thermal, Polymorphic, and Crystallization Behaviors of Granular Crystals Formed in Beef Tallow and Palm Oil

Six rectangular block all beef tallow (BT)-based and all palm oil (PO)-based model shortenings prepared on a laboratory scale, respectively denoted BTMS and POMS, were stored under temperature fluctuation cycles of 5-20 °C until granular crystals were observed. The lipid composition and thermal, polymorphic, and isothermal crystallization behaviors of the granular crystals and their surrounding materials separated from BTMS and POMS, respectively, were evaluated. The changes of nanostructure including the aggregation of high-melting triacylglycerols (TAGs) and polymorphic transformation from β' form of double chain length structures to complicated crystal structures, in which the β and β' form crystals of triple and double chain length structures simultaneously coexist, had occurred in granular crystals compared with surrounding materials, whether in BTMS or in POMS. Consequently, a slower crystallization rate appeared in granular crystal parts of both model shortenings noted above, which would yield larger and fewer crystals indicated by the Avrami model analysis that would further aggregate to form large granular crystals.

Effect of Blending and Emulsification on Thermal Behavior, Solid Fat Content, and Microstructure Properties of Palm Oil‐Based Margarine Fats

The ability of palm oil (PO) to crystallize as beta prime polymorph has made it an attractive option for the production of margarine fat (MF). Palm stearin (PS) expresses similar crystallization behavior and is considered one of the best substitutes of hydrogenated oils due to its capability to impart the required level of plasticity and body to the finished product. Normally, PS is blended with PO to reduce the melting point at body temperature (37 °C). Lipid phase, formulated by PO and PS in different ratios were subjected to an emulsification process and the following analyses were done: triacylglycerols, solid fat content (SFC), and thermal behavior. In addition, the microstructure properties, including size and number of crystals, were determined for experimental MFs (EMFs) and commercial MFs (CMFs). Results showed that blending and emulsification at PS levels over 40 wt% significantly changed the physicochemical and microstructure properties of EMF as compared to CMF, resulting in a desirable dipalmitoyl-oleoyl-glycerol content of less than 36.1%. SFC at 37 °C, crystal size, crystal number, crystallization, and melting enthalpies (ΔH) were 15%, 5.37 μm, 1425 crystal/μm(2), 17.25 J/g, and 57.69J/g, respectively. All data reported indicate that the formation of granular crystals in MFs was dominated by high-melting triacylglycerol namely dipalmitoyl-oleoyl-glycerol, while the small dose of monoacylglycerol that is used as emulsifier slowed crystallization rate. Practical Application: Most of the past studies were focused on thermal behavior of edible oils and some blends of oils and fats. The crystallization of oils and fats are well documented but there is scarce information concerning some mechanism related to crystallization and emulsification. Therefore, this study will help to gather information on the behavior of emulsifier on crystallization regime; also the dominating TAG responsible for primary granular crystal formations, as well as to determine the best level of stearin to impart the required microstructure properties and body to the finished products.

Characterization of Graininess Formed in All Beef Tallow-Based Shortening

A batch of all beef tallow (BT)-based model shortening (divided into six rectangular block samples) was stored under temperature fluctuation cycles of 5-20 °C until granular crystals were observed. The lipid composition, thermal properties, and polymorphism of the granular crystals and their surrounding materials were evaluated. Furthermore, the isothermal crystallization behavior of two parts noted above was also examined by pulsed nuclear magnetic resonance (pNMR), rheology, and polarized light microscopy (PLM). The changes of nanostructure including the aggregation of high-melting triacylglycerols (TAGs) and transformation into the most stable β polymorph occurred in granular crystals compared with surrounding materials. Concomitantly, a slower crystallization rate with a simultaneous increase in crystal growth led to the formation of large crystals and further aggregated to larger granular crystals when the size ultimately exceeded the sensory threshold.

Contribution to the study of camel milk fat globule membrane

The camel milk fat globule membrane has been characterized according to several approaches. Compared with the cow milk fat globule membrane, various specificities have been revealed. Its physicochemical composition showed a poor content in proteins, and a higher content in neutral lipids and in phospholipids. The mechanical properties measured at low (4°C, 20°C) and high temperatures (40°C, 45°C and 50°C) using a film balance are different when the camel milk fat globule membrane is spread at the air–water interface. The thermal study revealed an important proportion of high-melting triacylglycerols that involves fatty acids with long chains.

PALM OIL CRYSTALLIZATION: EFFECTS OF COOLING TIME AND OIL CONTENT

ABSTRACT Isothermal crystallization behavior of fluid shortening formulation from blends of palm oil and palm olein was investigated. The oil blends filled in nuclear magnetic resonance (NMR) tubes to a height of 2.5 cm were melted at 70C for 30 min crystallization time. A set of 11 tubes for each temperature was placed at selected crystallizing time and the solid fat content (SFC) measured in a Bruker pulse NMR spectrometer. Crystal distribution of the same blend was observed under polarized microscope at the same time interval. A correlation was developed between SFC and crystal distribution. The crystallization curves demonstrated two distinct steps corresponding to two crystallization stages as a result of the occurrence of mixed crystallization. Crystallization was selective to the high melting triacylglycerols (TAG) at all temperatures as shown by shorter induction periods in blends with more than 41.8% palmitic acid. High melting TAG crystallized first and acted as nuclei for recrystallization of the low melting TAG. However, the low melting TAG at the same time could also solubilize the formed crystals. The average SFC as a function of time was 50% lower than the SFC profile. Slow crystallization temperature was able to promote large crystal formation that influences SFC of palm‐based shortenings. Blends of 40–60% palm oil showed promising formulations of stable fluid palm‐based shortening.

Chemical and thermal characteristics of buffalo butter oil fractions obtained by multi-step dry fractionation

Buffalo butter oil was fractionated by stepwise crystallization at several temperatures between 15–40°C using slow cooling of melted butter oil (80°C) with agitation (10 rpm) in conjunction with vacuum filtration to produce five solid and five liquid fractions. Fractions were analysed for fatty acid (FA) composition, acyl-carbon profile and evaluated for solid fat content (SFC) by pulsed nuclear magnetic resonance and thermal profile by differential scanning calorimeter (DSC). Based on chemical and thermal properties, the fractions were divided into three main groups: high-melting fractions (HMF), middle-melting fractions (MMF) and low-melting fractions (LMF). HMF (slip melting point (SMP) 36.5–45°C) were enriched in saturated long-chain fatty acids and reduced in short-chain fatty acids and unsaturated fatty acids. Conversely, LMF (SMP 12.6°C) were reduced in saturated-long chain fatty acids and enriched in short-chain fatty acids and unsaturated fatty acids. FA composition of MMF (SMP 24.2–29.8°C) lie between those of LMF and HMF. Likewise, high-melting triacylglycerol (HMTAG) were concentrated in HMF (44.17–59.67 mg/100 mg), whereas low-melting triacylglycerol (LMTAG) were predominately in LMF (17.51 mg/100 mg). MMF were enriched in middle-melting triacylglycerol (MMTAG) (44.10–51.67 mg/100 mg). Multi-step dry fractionation caused substantial differences in the thermal profile of the obtained fractions. SFC of HMF and MMF was 17.7–31.5 g/100 g and 4.0–20.5°C g/100 g at 25°C, respectively while LMF was entirely liquid at this temperature. HMF have a significantly higher ( P<0.05) melting characteristics compared with LMF as analysed by DSC with melting enthalpies of 48.46–71.28 J/g for the former and 15.81 J/g for the latter. Melting peak temperature increased from 9.25°C in LMF to 33.54–40.46°C in HMF.

Physical and chemical properties of a lipase-transesterified palm stearin/palm kernel olein blend and its isopropanol-solid and high melting triacylglycerol fractions

Abstract Palm stearin and palm kernel olein at 1:1 (w/w) ratio was transesterified using 1.0% w/w lipase from Rhizomucor miehei (Lipozyme IM60, Novo Nordisk). The transesterified blend, as well as its isopropanol-solid (fat solid fractionated using isopropanol at 5 °C) and high melting glycerides (HMG, fat solid fractionated using acetone at 10 °C) were studied. Low carbon number triacylglycerols (TG), ranging from C32 to C38, and high carbon number TG (C48 and C50) were used to produce TG ranging from C40 to C46. Transesterification did not much alter the fatty acid (FA) composition of the mixture, but it increased the level of C12:0 (lauric acid) and reduced the C16:0 (palmitic acid) level in the isopropanol-solid and HMG fractions compared to the control. Transesterification also did not much alter the polymorphic forms of the mixture. However, the HMG fraction of the transesterified mixture had more tendency to form β′ crystals than the control. Slip melting point of transesterified fat was lower than the control. Heating thermograms of differential scanning calorimetry (DSC) illustrated that the high-melting TG peaks in the transesterified blend were reduced in size while the low-melting TG peaks were broadened, mainly due to the rearrangement of FA to form lower-melting TG. The temperature of the high-melting TG peaks of all samples showed a good correlation (correlation coefficient, r=0.9899; P

FUNCTIONALITY OF PALM OIL IN FOODS

ABSTRACTThe functional properties of commercial solid fats such as shortening and margarine are closely related to their fatty acid and triacylglycerol compositions. Plastic fats produced from hydrogenated seed oils may suffer from undesirable crystal structure changes during handling and storage. It has been demonstrated that this problem increases with increasing chain length uniformity of the component fatty acids. This is also evidenced by the carbon number composition of the high melting triacylglycerols of the plastic fats. Triacylglycerols with carbon numbers 48 and 54 promote β crystallization, those with carbon numbers 50 and 52 promote β′ crystallization. Since palm oil and its products contain high levels of C50 and C52 triacylglycerols they are useful for improving the functional properties of plastic fats.