Physical and textural characteristics of some North American shortenings

A number of North American vegetable and animal fat shortenings were evaluated for their melting, crystallization, textural and polymorphic crystal characteristics and solid fat content (SFC). The majority of the dropping points and crystallization temperatures of the fats ranged from 42 to 46°C and from 27 to 31°C, respectively. Softening points of the products were higher than the dropping points of their fats, especially for the vegetable shortenings. Differential scanning calorimetry melting curves of the products were different for the various products. The animal fat shortenings were mainly in theβ-polymorphic form, while vegetable shortenings containing palm oil were in theβ′ form. Textural evaluation was carried out on the products with the cone penetrometer, constant speed penetration and constant speed compression. Constant speed compression supplied a measure of brittleness and a degree of viscosity. Lard and shortenings containing high levels of palm oil were able to withstand large deformations without breakage. The effect of tempering temperature of the fat in the SFC determination was evaluated and the values obtained were compared with the SFC of the actual product. SFC of fat and product were determined by pulse nuclear magnetic resonance. Correlation of values within textural methods was significant (P<..01), but were not significant between texture and SFC of the fat, indicating that the nature of the crystal network also plays a role in texture.     

Physico-chemical properties and performance of high oleic and palm-based shortenings

Solid fat from fractionation of palm-based products was converted into cake shortening at different processing conditions. High oleic palm stearin with an oleic content of 48.2 % was obtained from fractionation of high oleic palm oil which was produced locally. Palm product was blended with different soft oils at pre-determined ratio and further fractionated to obtain the solid fractions. These fractions were then converted into cake shortenings named as high oleic, N1 and N2 blends. The physico-chemical properties of the experimental shortenings were compared with those of control shortenings in terms of fatty acid composition (FAC), iodine value (IV), slip melting point (SMP), solid fat content (SFC) and polymorphic forms. Unlike the imported commercial shortenings as reported by other studies and the control, experimental shortenings were trans-free. The SMP and SFC of experimental samples, except for the N2 sample, fell within the ranges of commercial and control shortenings. The IV was higher than those of domestic shortenings but lower when compared to imported and control shortenings. They were also observed to be beta tending even though a mixture of beta and beta' was observed in the samples after 3 months of storage. The shortenings were also used in the making of pound cake and sensory evaluation showed the good performance of high oleic sample as compared to the other shortenings.     

Effects of Processing and Composition on the Crystallization and Mechanical Properties of Water-in-Oil Emulsions

This research investigated the role of agitation, high-melting emulsifier and water content on the crystallization process and the texture of water-in-oil emulsions produced on a pilot plant scale using a scraped surface heat exchanger (SSHE). Our results indicated that shear affected the hardness of the emulsions as they exited the SSHE, with softer emulsions processed at higher shear; once the emulsions reached equilibrium temperature, no differences in texture due to shear were observed. The added emulsifier delayed the crystallization of emulsions processed in the SSHE with no further effect on the equilibrium solid fat content (SFC) or textural properties of emulsions after 24 h of storage. The texture of the crystallized emulsions at early stages of processing was influenced by the amount of water and water droplet size; the larger the amount of water and the smaller the droplets, the higher the hardness of emulsions. Once the emulsions reached equilibrium temperature, further crystallization took place, and the texture depended only on the SFC.     

CLA‐Rich Soy Oil Shortening Production and Characterization

Conjugated linoleic acid‐rich soy oil (CLARSO) has been shown to have numerous health benefits, including anti‐obesity and anti‐carcinogenic properties. This oil was previously used to produce CLA‐rich margarine that showed physical characteristics similar to commercially available margarine. The objective of this study was to produce CLA‐rich shortening and analyze its physical properties relative to commercially available shortenings and soy oil control shortenings. The shortenings were prepared and their rheology, thermal behavior, and solid fat content (SFC) were determined and compared to the commercial samples. The CLA‐rich shortening samples showed similar rheological properties to the commercial samples and showed a better consistency (more solid‐like behavior) compared to the soy oil control samples. In addition, the CLA‐rich shortenings also have a higher SFC (% SFC) as well as higher latent heat of crystallization and melting than the soy oil controls indicating a comparatively higher crystalline fraction. Thus, CLARSO produced firmer shortenings than did conventional soy oil by interacting with the crystallizing stearin fraction and consequently increasing the crystalline mass fraction without significantly altering the microstructure kinetics of solid fat crystallization.     

The influence of food emulsifiers on fat and sugar dispersions in oils. III. Water content,purity of oils

The influence of water on the interactions between fat and sugar crystals dispersed in triglyceride (vegetable) oils was qualitatively estimated from sedimentation and rheological experiments. The experiments were performed both with and without food emulsifiers (monoglycerides and lecithins) present in the oil. The effects of minor natural oil components (nontriglycerides) on the interactions and on emulsifier adsorption to the crystals were examined by comparing a commercial refined oil and a chromatographically purified oil. The results show that water generally increases the adhesion between fat and sugar crystals in oils and also increases the surface activity of the oil-soluble food emulsifiers. Minor oil components give a small increase in the adhesion between fat and sugar crystals in oils, but do not influence the adsorption of food emulsifiers in any systematic way.     

<Emphasis Type="Italic">Trans</Emphasis>-Free Plastic Shortenings Prepared with Palm Stearin and Rice Bran Oil Structured Lipid

Rice bran oil structured lipid (RBOSL) was produced from rice bran oil (RBO) and the medium chain fatty acid (MCFA), caprylic acid, with Lipozyme RM IM as biocatalyst. RBOSL and RBO were mixed with palm stearin (PS) in ratios of 30:70, 40:60, 50:50, 60:40 and 70:30 v/v (RBOSL to PS) to formulate trans-free shortenings. Fatty acid profiles, solid fat content (SFC), melting and crystallization curves and crystal morphology were determined. The content of caprylic acid in shortening blends with RBOSL ranged from 9.92 to 22.14 mol%. Shortening blends containing 30:70 and 60:40 RBOSL or RBO and PS had fatty acid profiles similar to a commercial shortening (CS). SFCs for blends were within the desired range for CS of 10–50% at 10–40 °C. Shortening blends containing higher amounts of RBOSL or RBO had melting and crystallization curves similar to CS. All shortening blends contained primarily β′ crystals. RBOSL blended with PS was comparable to RBO in producing shortenings with fatty acid profiles, SFC, melting and crystallization profiles and crystal morphologies that were similar. RBOSL blended with PS can possibly provide healthier alternative to some oils currently blended with PS and commercial shortening to produce trans-free shortening because of the health benefits of the MCFA in RBOSL.     

Plastic fats with zero trans fatty acids by interesterification of mango,mahua and palm oils

Speciality plastic fats with no trans fatty acids suitable for use in bakery and as vanaspati are prepared by interesterification of blends of palm hard fraction (PSt) with mahua and mango fats at various proportions. It was found that the interesterified samples did not show significant differences in solid fat content (SFC) after 0.5 or 1 h reaction time. The blends containing PSt/mahua (1:1) showed three distinct endotherms, indicating a heterogeneity of triacylglycerols (TG), the proportions of which altered after interesterification. The SFC also showed improved plasticity after interesterification. Similar results were observed with other blends of PSt/mahua (1:2). These changes in melting behavior are due to alterations in TG composition, as the trisaturated‐type TG were reduced and the low‐melting TG increased after interesterification. The blends containing PSt/mango (1:1) showed improvement in plasticity after interesterification, whereas those containing PSt/mango (2:1) were hard and showed high solid contents at higher temperature and hence may not be suitable for bakery or as vanaspati. The blends with palm and mahua oils were softer and may be suitable for margarine‐type products. The results showed that the blends of PSt/mahua (1:1, 1:2) and PSt/mango (1:1) after interesterification for 1 h at 80 °C showed an SFC similar to those of commercial hydrogenated bakery shortenings and vanaspati. Hence, they could be used in these applications in place of hydrogenated fats as they are free from trans acids, which are reported to be risk factors involved in coronary heart disease. For softer consistency like margarine applications, the blends containing palm oil and mahua oil are suitable.     

Enzymatic Production of Highly Unsaturated Monoacyglycerols and Diacylglycerols and Their Emulsifying Effects on the Storage Stability of a Palm Oil Based Shortening System

MDs [monoacylglycerols (MAGs) and diacylglycerols (DAGs) mixture] are widely‐used emulsifiers in specialty fats industrial production. An enzymatic production of highly unsaturated MDs (HUSMDs) and its effects on the storage stability of a palm oil‐based shortening system are reported. Oleic acid and corn oil were used to produce HUSMDs in a bubble column reactor (BCR) system in the presence of Novozyme 435. Under the optimized reaction conditions, the content of HUSMDs in the products was above 82 wt% with 46.67 wt% of MAGs and 35.56 wt% DAGs, respectively. Moreover, in the subsequent evaluation of MDs’ effects on the storage stabilities of a palm oil‐based shortening system (IEPO), HUSMDs proved to be a potent emulsifier with decent aeration properties and a possible alternative to saturated MAGs and DAGs (SMDs) made from fully hydrogenated high erucic acid colza oil. Compared with SMDs, HUSMDs decreased the crystallization rate significantly. The microstructure of them shows improved stability of β′ crystals, and no obvious aggregation of crystals was recorded in IEPO with HUSMDs, which also demonstrated the most stable hardness.     

Interfacial Crystallization of Diacylglycerols Rich in Medium‐ and Long‐Chain Fatty Acids in Water‐in‐Oil Emulsions

The effects of diacylglycerols rich in medium‐ and long‐chain fatty acids (MLCD) on the crystallization of hydrogenated palm oil (HPO) and formation of 10% water‐in‐oil (W/O) emulsion are studied, and compared with the common surfactants monostearoylglycerol (MSG) and polyglycerol polyricinoleate (PGPR). Polarized light microscopy reveals that emulsions made with MLCD form crystals around dispersed water droplets and promotes HPO crystallization at the oil‐water interface. Similar behavior is also observed in MSG‐stabilized emulsions, but is absent from emulsions made with PGPR. The large deformation yield value of the test W/O emulsion is increased four‐fold versus those stabilized via PGPR due to interfacial crystallization of HPO. However, there are no large differences in droplet size, solid fat content (SFC), thermal behavior or polymorphism to account for these substantial changes, implying that the spatial distribution of the HPO crystals within the crystal network is the driving factor responsible for the observed textural differences. MLCD‐covered water droplets act as active fillers and interact with surrounding fat crystals to enhance the rigidity of emulsion. This study provides new insights regarding the use of MLCD in W/O emulsions as template for interfacial crystallization and the possibility of tailoring their large deformation behavior. Practical Applications: MLCD is applied in preparing W/O emulsion. It is found that MLCD forms unique interfacial Pickering crystals around water droplets, which promote the surface‐inactive HPO nucleation at the oil‐water interface. Thus MLCD‐covered water droplets act as active fillers and interact with surrounding fat crystals, which can greatly enhance the rigidity of emulsion. This observation would provide a theoretical reference and practical basis for the application of the MLCD with appreciable nutritional properties in lipid‐rich products such as whipped cream, shortenings margarine, butter and ice cream, so as to substitute hydrogenated oil. MLCD‐stabilized emulsions can also be explored for the development of novel confectionery products, lipsticks, or controlled release matrices.     

Physical properties of palm‐based diacylglycerol and palm‐based oils in the preparation of shelf‐stable margarine

Ternary mixtures containing palm olein (POL), palm kernel oil (PKO) and palm oil‐based diacylglycerol (PO‐DAG) were designed using mixture design. The corresponding physical properties such as solid fat content (SFC) as well as deviation from SFC (ΔSFC) using nuclear magnetic resonance (NMR) and melting and crystallization properties using differential scanning calorimetry (DSC) were studied. Ternary phase behaviour was analysed using isosolid diagrams. The most intensive eutectic interaction among the three binary blends studied was observed along the binary line of PKO/PO‐DAG followed by POL/PKO and POL/PO‐DAG. The higher ΔSFC did not always lead to the more intensive eutectic behaviour among the blends. Addition of pure POL, 33.33 and 66.66% POL, and no POL to 50/50 mixture of PKO/PO‐DAG decreased heat of crystallization (ΔHc) as well as crystallization onset (T_O). However, as the same amounts of PO‐DAG and PKO were added to the 50/50 mixtures of POL/PKO and POL/PO‐DAG, respectively, blend containing the equi‐mixture of POL, PKO and PO‐DAG (33.33/33.33/33.33) was found to have the lowest ΔHc. This was also reflected in the corresponding eutectic effect observed at 20–25 and 5–10°C, respectively. Palm‐based DAG‐enriched shelf‐stable margarine consisting of POL/PKO/PO‐DAG (42.5/42.5/15 w/w) was optimally formulated through analysis of multiple isosolid diagrams and was found to have quite similar SFC profile with commercial shelf‐stable margarine. Practical applications: In this study, valuable information about complicated interactions among the palm oil‐based diacylglycerol (PO‐DAG) and palm‐based oils with different FA chain length was obtained in the ternary system. These informative data may be useful in future exploitation of solid fat‐based DAG in blend with natural fats for various DAG‐enriched plastic fat products. Furthermore, Design Expert software was found to be a valuable tool to optimize the new fat blend formulation using the minimum number of blend preparation. By using this tool, assessment of complicated behaviour among the blend components through construction of the corresponding phase diagrams which are critical for optimization purposes as well as fat product development, would also be possible.     

Application of palm olein in the production of zero‐trans Iranian vanaspati through enzymatic interesterification

The utilization of palm olein in the production of zero‐trans Iranian vanaspati through enzymatic interesterification was studied. Vanaspati fat was made from ternary blends of palm olein (POL), low‐erucic acid rapeseed oil (RSO) and sunflower oil (SFO) through direct interesterification of the blends or by blending interesterified POL with RSO and SFO. The slip melting point (SMP), the solid fat content (SFC) at 10–40 °C, the carbon number (CN) triacylglycerol (TAG) composition, the induction period (IP) of oxidation at 120 °C (IP₁₂₀) and the IP of crystallization at 20 °C of the final products and non‐interesterified blends were evaluated. Results indicated that all the final products had higher SMP, SFC, IP of crystallization and CN 48 TAG (trisaturated TAG), and lower IP₁₂₀, than their non‐interesterified blends. However, SMP, SFC, IP₁₂₀, IP of crystallization and CN 48 TAG were higher for fats prepared by blending interesterified POL with RSO and SFO. A comparison between the SFC at 20–30 °C of the final products and those of a commercial low‐trans Iranian vanaspati showed that the least saturated fatty acid content necessary to achieve a zero‐trans fat suitable for use as Iranian vanaspati was 37.2% for directly interesterified blends and 28.8% for fats prepared by blending interesterified POL with liquid oils.     

Relationship between characteristics of oil droplets and solidification of thermally treated creams

The relationship between the characteristics of oil droplets and the change in appearance of cream was investigated. The model creams (40 wt% oil-in-water emulsion), similar to commerical products, were prepared with vegetable fat, milk protein, and emulsifier. The thermal treatment, in which the cream was exposed to a certain temperature and subsequently recooled, was performed on the assumption that the temperature was temporarily elevated during transportation and storage of commercial products. Solidification of the cream was observed when it was exposed to a temperature where there was a small percentage in solid fat content (SFC) of fat in oil droplets and recooled, whereas the cream remained in the liquid state when it was exposed to the temperature where SFC was zero and recooled. When the SFC of oil droplets was 0% at the treated temperature, greater supercooling prior to fat crystallization occurred and the crystallization rate after the initial formation of crystals was much higher. On the other hand, the polymorphism of fat in the droplets was not directly affected by the thermal treatment. These results indicate that the crystallization in oil droplets at the heating temperature may be closely connected with the destablization of oil droplets via a partial coalescence mechanism, which will cause the solidification of cream.     

Chemical composition and physical properties of soft (tub) margarines sold in Malaysia

Seven samples of domestic and imported Malaysian tub margarines were analyzed for their fatty acid and triglyceride (carbon number) composition, solid fat content, dropping and softening points, crystallization temperature, polymorphic form, color, and textural attributes. Domestic margarines were formulated from palm oil or palm olein and palm kernel oil with a liquid oil but no hydrogenated oils. Two imported products contained hydrogenated palm oil product, which resulted in a high level of β′ crystals, whereas the domestic nonhydrogenated products contained more β than β′ crystals. Crystal habit was related to the fatty acid and triglyceride composition of the high-melting glycerides. Domestic products were firmer in texture, probably because they were formulated to be sold in a tropical climate.     

Properties of Oleogels Formed With High‐Stearic Soybean Oils and Sunflower Wax

In an effort to develop alternatives for harmful trans fats produced by partial hydrogenation of vegetable oils, oleogels of high‐stearic soybean (A6 and MM106) oils were prepared with sunflower wax (SW) as the oleogelator. Oleogels of high‐stearic oils did not have greater firmness when compared to regular soybean oil (SBO) at room temperature. However, the firmness of high‐stearic oil oleogels at 4 °C sharply increased due to the high content of stearic acid. High‐stearic acid SBO had more polar compounds than the regular SBO. Polar compounds in oil inversely affected the firmness of oleogels. Differential scanning calorimetry showed that wax crystals facilitated nucleation of solid fats of high‐stearic oils during cooling. Polar compounds did not affect the melting and crystallization behavior of wax. Solid fat content (SFC) showed that polar compounds in oil and wax interfered with crystallization of solid fats. Linear viscoelastic properties of 7% SW oleogels of three oils reflected well the SFC values while they did not correlate well with the firmness of oleogels. Phase‐contrast microscopy showed that the wax crystal morphology was slightly influenced by solid fats in the high‐steric SBO, A6.     

Comparison of lipase-transesterified blend with some commercial solid frying shortenings in Malaysia

A transesterified experimental solid frying shortening was prepared from a palm stearin/palm kernel olein blend at 1∶1 ratio (by weight) by using Rhizomucor miehei lipase at 60°C for 6 h. The fatty acid (FA) and triacylglycerol compositions, polymorphic forms, melting and cooling characteristics, slip melting point (SMP), and solid fat content (SFC) of the transesterified blend were then compared with five commercial solid frying shortenings (three domestic and two imported) found in Malaysia. All the domestic shortenings contained nonhydrogenated palm oil or palm olein and palm stearin as the hard stock, whereas the imported frying shortenings were formulated from soybean oil and cottonseed oil and contained high level of β′ crystals. Trans FA were also found in these samples. The lipase-transesterified blend was found to be more β′-tending than the domestic samples. The SMP of the transesterified blend (47.0°C) fell within the range of the domestic samples (37.8–49.7°C) but was higher than the imported ones (42.3–43.0°C). All samples exhibited similar differential scanning calorimetry cooling profiles, with a narrow peak at the higher temperatures and a broad peak at the lower temperatures, even though their heating thermograms were quite different. Imported samples had flatter SFC curves than both the experimental and domestic samples. The domestic samples were found to have better workability or plasticity at higher temperatures than the imported ones, probably because they were formulated for a tropical climate.     

Effect of Milk Fat Concentration on Fat Crystallization of Palm Oil-Based Shortenings

The effect of different dosages of anhydrous milk fat (AMF) (25%, 50% and 75%, w/w) on shear-crystallization of fat blends made of refined palm oil, refined palm stearin, and rapeseed oil was studied. Classical techniques as differential scanning calorimetry (DSC), pulsed field gradient nuclear magnetic resonance (pfg-NMR), rheometer, and X-ray diffraction (XRD) were applied to evaluate the crystallization kinetics of fat blends as well as the fat compatibility between components in rapid cooling (15 °C min⁻¹), isothermal crystallization (at 15 °C), and storage (5 °C). Obtained results revealed that the mixtures of palm oils and milk fat had a low compatibility. The co-crystallization between triacylglycerols (TAG) of milk fat and of palm oil occurred during isothermal crystallization and storage resulting in slower crystallization kinetics and the formation of some eutectic mixtures.     

Crystallization Rates of Palm Oil and Modified Palm Oils

Differential scanning calorimetry and pulsed nuclear magnetic resonance were used in the estimation of crystallization kinetics of palm oil and modified palm oils. Differential scanning calorimetry was found to be more sensitive and could differentiate between crystallization during cooling and crystallization during isothermal conditions. Hydrogenated palm oils crystallized quickly and completely when cooled from 60° to 20°C, while palm oil and fractionated palm stearin continued to crystallize when held isothermally at 20°C.     

Zero‐Trans Cake Shortening: Formulation and Characterization of Physicochemical,Rheological, and Textural Properties

Cake shortening is an important ingredient that imparts taste and texture in the cake as the final product. Hydrogenated shortenings contain high amounts of trans fatty acids, which is considered a risk factor for obesity, cancers, and cardiovascular diseases. In this research, chemically interesterified blends of canola oil (CO) and palm stearin (PS) were recruited in order to formulate zero‐trans shortening, specifically for cake application. The optimization of shortening formulation was performed by Design‐Expert software, considering melting, congelation, textural, and rheological properties of cake shortening as responses. The formulated shortening in the weight ratio of 66.41:33.58 (PS:CO) (%, w/w) was analyzed and compared with two commercial cake shortenings in terms of fatty acid and triacylglycerol composition, slip melting point (SMP), solid fat content (SFC), and rheological and textural properties. The results showed that the formulated zero‐trans cake shortening with 0.2% trans, 47.2% saturated fatty acids, SMP of 40.9 °C, SFC of 10.51% at 37 °C, firmness of 1522.5 g, and linear viscoelastic range of 0.035% had the most acceptable criteria among cake‐shortening samples. The findings of this study offer insights into the relationship between shortening functionality and physicochemical properties and serve as a base for future studies on zero‐trans shortenings formulation.     

Influence of Different Factors on the Particle Size Distribution and Solid Fat Content of Water-in-Oil Emulsions

The influence of the variation of different parameters on the particle size distribution and solid fat content (SFC) of water‐in‐oil emulsions was studied. The use of solid fat instead of liquid oil, higher polyglycerol polyricinoleate (PGPR) concentration, or higher homogenization energy led to smaller mean particle sizes. The decrease of the emulsifier/water ratio turned the particle size distribution of the emulsions from bimodal to trimodal. The increase of PGPR concentration increased the SFC of the fat in the absence of water, but it did not produce the same effect in the emulsion. This result suggested that the presence of dispersed aqueous phase prevented the modifying action of the emulsifier on the crystallization of the continuous lipid phase. The experimentation indicated that the adsorption of the surfactant at the interface would reduce its availability to affect crystallization in bulk fat, as the SFC in lipid phase decreased with increasing interfacial area.     

Accelerated Fat Bloom in Chocolate Model Systems: Solid Fat Content and Temperature Fluctuation Frequency

Chocolate model systems were designed with high‐melting fat (cocoa butter stearin, CB‐S) mixed with low‐melting fats (sunflower oil, canola oil, cottonseed oil, peanut oil) to give 45, 55, and 65 % solid fat content (SFC). Defatted cocoa powder provided a 50 % particulate level in the model chocolates. The effects of SFC, low‐melting fat type and storage temperature fluctuation frequency on bloom whiteness were investigated. Both SFC and storage condition had significant influences on bloom whiteness (p < 0.0001), although the type of low‐melting fat did not (p = 0.1223). Increasing the SFC significantly reduced bloom formation, as did more rapid temperature fluctuations.