Stearin Fractions Research Articles

Changes in Physicochemical Characteristics and Microbiological Quality of Bakery Shortening Formulated with Shea Butter and Fluted Pumpkin Seed Oil During Storage

The objective of this work was to evaluate the changes that occur in physicochemical characteristics and microbiological qualityof bakery shortening formulated with Shea stearin and fluted pumpkin seed oil blends during storage, so as to ascertain its storage stability. Edible oils were extracted from Shea nuts ( Vitellaria paradoxa Geartner) and Fluted pumpkin ( Telfairia occidentalis Hook ) seeds. The extracted Shea butter and fluted pumpkin seed oil samples were refined and modified using two methods namely fractionation and chemical interesterification to produce bakery fats. The Shea butter was fractionated, and the solid stearin fraction blended with fluted pumpkin seed oil in the following ratios: 30:70, 40:60, and 50:50, (Shea stearin: fluted pump seed oil), The blends were stabilized with recommended additives such as; distilled monoglyceride (E471) and preservatives such as; citric acid (E330), BHT (E321), and sodium benzoate (E211), homogenized by continuous stirring and plasticized by chilling to 17°C, then tempered at 23 – 25°C for 48h, to attain a stable polymorphic form, used as fractionated blends (FRBs). Another set of 30:70; 40:60; and 50:50 (Shea stearin: fluted pumpkin seed oil), were chemically interesterified with sodium methoxide (CH3ONa) as catalyst, crystalized, stabilized, and used as chemically interesterified fractionated blends (CIEFBs). The products were packed and sealed in opaque plastic cups and stored at room temperature (28±2°C) for 90 days. Changes in physicochemical properties (including solid fat content) and microbiological quality (yeast and moulds count) were determined. Peroxide value (PV) and acid value (AV) of the bakery fats formulated with fractionated blends increased slightly after 90 days of storage. There were no significant (P>0.05) increase in PV of the interesterified samples after storage for 90 days. No significant change was recorded in the iodine value, slip melting point, and smoke point of the products on storage, except the 30:70 fractionated blend which reduces in iodine value (IV) and smoke point from 94.60g/100g to 92.50g/100g, and 200.30°C – 198.00°C, respectively. The products were microbiologically stable throughout the period of storage.

Functional properties of chicken fat-based shortenings: Effects of based oils and emulsifiers

ABSTRACTIn order to broaden the use of chicken fat (CF), a new shortening was developed using stearin fractions of CF as a raw material. The CF was mixed with different base oils, and the compatibility, plasticity, and polymorphism of the mixture were analyzed. The influence of emulsifiers on the water-absorbing and air-absorbing abilities, and rheology of the CF-based shortening was studied. The mixtures of CF with palm oil at a mass ratio of 7:3 and CF with beef tallow at a mass ratio of 5:5 exhibited good compatibility, plasticity for baking, and crystal structure. By analysis of water-absorbing and air-absorbing abilities, the optimal amount of emulsifiers in both mixtures was determined as 1%, and the ratios of distilled monostearate, SPAN 60, and lecithin were determined to be 0.45:0.45:0.1 and 0.45:0.1:0.45 in the mixtures of CF with palm oil and CF with beef tallow, respectively. Different emulsifiers had significant effects on the rheological properties of CF-based shortenings. In addition, mixed emulsifiers had greater effects on the water-absorbing and air-absorbing abilities of the shortening than single emulsifier.Abbreviations: BT: Beef tallow; CF: Chicken fat; DMS: Distilled monostearate; DSC: Differential scanning calorimeter; HPO: Hydrogenated palm oil; PO: Palm oil; POO: Palm oil olein; POS: Palm oil-based shortenings; PS: Palm stearin; SFC: Solid fat content; SMP: Slip melting point; XRD: X-ray diffraction.

Solvent fractionation of rambutan (Nephelium lappaceum L.) kernel fat for production of non-hydrogenated solid fat: Influence of time and solvent type

The present study performed isothermal (25°C) solvent fractionation of rambutan (Nephelium lappaceum L.) kernel fat (RKF) to obtain the fat fraction that had melting properties comparable to a commercial hydrogenated solid fat. The effect of two fractionation parameters, holding time (12, 18 and 24h) and solvent types (acetone and ethanol), on the properties of fractionated fat were investigated. The results showed that a fractionation time increase caused an increased yield and decreased iodine value for the high melting or stearin fractions. The thermal behaviors and solid fat index (SFI) of these stearin fractions were different from the original fat, especially for stearin from acetone fractionation. The major fatty acid in this stearin fraction was arachidic acid (C20:0) consisting of more than 90%. Overall, we demonstrated that acetone fractionation of RKF at 25°C for 24h is effective for producing a solid fat fraction, which has comparable crystallizing and melting properties to commercial hydrogenated fat. The fractionated rambutan fat obtained by this process may lead to its potential use in specific food products.

Fractionation of chia oil for enrichment of omega 3 and 6 fatty acids and oxidative stability of fractions.

Omega 3 and 6 fatty acids were enriched in the olein fraction of chia oil via dry fractionation at -30°C. Concentrations of C18:3 (linolenic acid, ω-3) and C18:2 (linoleic acid, ω-6) were 78.16 and 25.42% in the olein fraction. HPLC characterization indicated enrichment of caffeic and chlorogenic acids, quercetin, and phenolic glycosides in the olein fraction. Total antioxidant activities of chia oil and the olein and stearin fractions were 42.5, 53.8, and 34.6%, respectively. After 6 months of storage at 4°C, the concentration of ω-3 in the olein fraction decreased from 78.19 to 76.16%, with a 10% decrease in the ω-3 concentration when the olein fraction was stored at 25°C. The stearin fraction of chia oil exhibited the longest induction period, followed by chia oil and the olein fraction. Amounts of ω-3 and 6 fatty acids can be enriched in the olein fraction from 11.92 and 61.28% to 15.22 and 72.16%, respectively, with reasonable storage stability at low temperature.

Effect of Crystalline Structure on Oxidation of Fish Oil in Stearin:Fish Oil Mixtures

Effects of incorporation of stearin fraction into fish oil on crystallisation behaviour and oxidative stability of fish oil were examined. The stearin fraction (S25) was obtained from step-wise dry fractionation of anhydrous milk fat at 25 °C. Analysis of fatty acid composition by gas chromatography showed that unsaturated fatty acids (89.3 %) were enriched in the fish oil whereas the S25 typically comprises of saturated fatty acids (79.4 %). A series of S25:fish oil mixtures (0:100, 25:75, 50:50, 75:25; 90:10 and 100:0) was prepared by mixing the S25 and fish oil at 50 °C under flushing of nitrogen gas. Crystallisation and thermal properties and crystal structures of the mixtures were investigated by differential scanning calorimetry and small- and wide-angle X-ray scattering, respectively. The crystallisation/melting temperatures and crystallisation/melting enthalpies of the mixtures increased with increasing ratios of S25 blended into fish oil. All mixtures showed similar crystal structures (double- and triple-chain length) and crystal polymorphs (α, β’ and β) at 4 °C. A decrease in S25 fraction in the mixtures caused a higher proportion of triple-chain length crystal packing and β polymorph. Measurement of peroxide values of the mixtures upon storage at 8 °C for 42 days showed that blending as low as 25 % S25 sufficiently delayed the lipid oxidation of fish oil by about two-fold and the rancidity threshold to 16 days instead of 9 days for fish oil only. This study demonstrates that mobility of oxygen and triacylglycerol (TAG) molecules in fish oil can be restricted by crystalline state of milk fat, in turn, limiting the propagation of oxidative reaction in fish oil.

Isopropanol Fractionation of Coconut Oil into its Olein and Stearin Fractions

Isopropanol Fractionation of Coconut Oil into its Olein and Stearin Fractions

CLA‐Rich Soy Oil Shortening Production and Characterization

AbstractConjugated 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.

Correlation between Thermal Properties and Chemical Composition of Palm Oil Top Olein Fractions

AbstractA multistep dry fractionation method for modification of palm oil was adopted to achieve a high iodine value (IV) of the obtained palm olein, herein denoted as top olein. The effect of the composition of palm oil top olein on the IV and on the crystallization properties was analyzed in detail. Thermal properties of a series of olein and stearin fractions were evaluated by means of differential scanning calorimetry upon cooling. The composition of triacylglycerols in the products was investigated by high‐performance liquid chromatography. IV analysis was carried out to measure the degree of unsaturation in these oil samples. Finally, an innovative and reliable method was developed to determine the IV of palm oils by relating the thermal properties with IV. The results agree well with those obtained by the traditional American Oil Chemists' Society method.

Effect of High‐Intensity Ultrasound on the Crystallization Behavior of High‐Stearic High‐Oleic Sunflower Oil Soft Stearin

AbstractThe objective of this research was to evaluate the effect of high‐intensity ultrasound (HIU) and crystallization temperature (Tc) on the crystallization behavior, melting profile, and elasticity of a soft stearin fraction of high‐stearic high‐oleic sunflower oil. Results showed that HIU can be used to induce and increase the rate of crystallization of the soft stearin with significantly higher SFC values obtained in the sonicated samples, especially at higher Tc. SFC values were fitted using the Avrami model, and higher kn and lower n values were obtained when samples were crystallized with sonication, suggesting that sonicated samples crystallized faster and through an instantaneous nucleation mechanism. In addition, the crystal morphology, melting behavior, and viscoelasticity were significantly affected by sonication.

Characterisation and use of single and double low temperature dry-fractionated olein and stearin from virgin olive oil

Single and double-fractionated olein and stearin were obtained by successive cooling of the virgin olive oil at 10 and 6 °C. Characteristics of the obtained fractions were compared with those of the virgin parent oil. Single-fractionated stearin (first stearin) constituted 65% (w/w) of the virgin oil, while double-fractionated stearin (second stearin) constituted 55% (w/w) of the single-fractionated olein (first olein). The fractionation process resulted in minor changes in the peak temperature and enthalpy change of the differential scanning calorimetry thermograms, and in minor changes in the physical, chemical sensory attributes of the oil fractions. The virgin oil and the stearin fractions were significantly (P≤0.05) more stable to oxidation as evaluated by the Rancimat method than the olein fractions. Mayonnaise and Italian salad dressing prepared from the double fractionated stearin had significantly (P≤0.05) superior consistency, smoothness and overall acceptability to those produced from the other...

Characterisation of high 1,3‐distearoyl‐2‐oleoyl‐sn‐glycerol content stearins produced by acidolysis of high oleic sunflower oil with stearic and palmitic acids

Nine different stearin fractions with 1,3‐distearoyl‐2‐oleoyl‐sn‐glycerol (StOSt) contents ranging from 69–84% were obtained via fractionation from fats produced by acidolysis of high oleic sunflower oil (HOSO) with various mixtures of stearic (either 95 or 98% pure) and palmitic acids (98% pure). Samples were further treated with silica to reduce the oxidised glyceride and DAG content. Isothermal crystallisation at 20°C showed a single main peak, but evidence of crystallisation during the initial DSC transient was also apparent for high StOSt content samples. This was confirmed as the α form by stop‐and‐return DSC and XRD. The main crystallisation event was generally faster (including a shorter induction time) for samples with higher StOSt levels (lower POSt levels). Silica treatment generally accelerated transformations to higher polymorphs (γ, β′ and β). Raman microscopy experiments showed that crystallisation of the β‐form was achieved after 7 days storage at 20°C but only in the silica treated stearin samples. This is consistent with higher solid fat content (SFC) values that were obtained with silica treated samples, which also increased with higher levels of StOSt. The results suggest that such stearins could potentially replace shea stearin in cocoa butter equivalents (CBE) formulations.Practical applications: This paper has two main practical applications: (i) Provides knowledge and understanding of the crystallisation and polymorphic behaviour of isolated hard stearins, obtained from enzymatic acidolysis of high oleic sunflower oil, which can be further used in CBE formulations. (ii) The presence of minor components significantly delays the crystallisation of the stearins, confirming the desirability of higher quality (less oxidised/hydrolysed) fat ingredients.

Viability of the Lactobacillus rhamnosus HN001 probiotic strain in Swiss- and Dutch-type cheese and cheese-like products.

The objective of this study was to determine the viability of the probiotic Lactobacillus rhamnosus HN001 in Swiss-type and Dutch-type cheese and cheese-like products (milk fat is substituted by stearin fraction of palm fat) during manufacture, ripening, and storage. The use of the probiotic L. rhamnosus HN001 in Dutch-type cheese and cheese-like products significantly (P = 0.1) changed their chemical composition (protein and fat content) and an insignificant increase (approximately 1.6% in cheese-like products and approximately 0.3% in cheese) in yield. L. rhamnosus HN001 did not affect the rate of changes in the pH of ripened cheese and cheese-like products. A minor increase in probiotic counts was observed in initial stages of production and were partially removed with whey. Ripened cheese and cheese-like products were characterized by high survival rates of probiotic bacteria which exceeded 8 log CFU/g after ripening. An insignificant reduction in the number of viable probiotic cells was noted during storage of Swiss-type and Dutch-type cheese, whereas a significant increase in probiotic cell counts was observed in cheese-like products during storage.

Antioxidant Activity of Sesame (Sesamum indicum L.) Cake Extract for the Stabilization of Olein Based Butter

AbstractThis study investigated the effect of ethanolic sesame cake extract on oxidative stabilization of olein based butter. Fractionation of cream was performed by the dry fractionation technique at 10 °C, ethanolic sesame cake extract (SCE) was incorporated into olein butter at three different concentrations; 50, 100, 150 ppm (T1, T2, T3) and compared with a control. The total phenolic content of SCE was 1.72 (mg gallic acid equivalent g−1 dry weight). The HPLC characterization of ethanolic sesame cake revealed the presence of antioxidant substances viz. sesamol, sesamin and sesamolin in higher extents. The DPPH free radical scavenging activity of SCE was 83 % as compared to 64 and 75 % in BHA and BHT. Fractionation of milk fat at 10 °C significantly (p < 0.05) influenced the fatty acid profile of olein and stearin fractions from the parent milk fat. Concentration of oleic acid and linoleic acid in olein fraction was 29.62 and 33.46 % greater than the parent milk fat. The loss of C18:1 in 90 days stored control and T3 was 24.37 and 3.58 %, respectively, 58 % C18:2 was broken down into oxidation products over 8.55 % loss in T3. The peroxide value of control, T1, T2, BHT and T3 in the Schaal oven test was 8.59, 8.12, 5.34, 4.52 and 2.49 (mequiv O2/kg). The peroxide value and anisidine value of 3 months stored control and T3 were 1.21, 0.42 (mequiv O2/kg) and 27.25, 13.25, respectively. The concentration of conjugated dienes in T3 was substantially less than the control. The induction period of T3 was considerably higher than BHT with no difference in sensory characteristics (p > 0.05). Ethanolic SCE can be used for the long‐term preservation of olein butter, with acceptable sensory characteristics.

Economic feasibility assessment of one and two stages dry fractionation of palm kernel oil

Palm kernel oil can be fractionated into stearin and olein fractions. Traditionally, industrial players only fractionate the softer stearin fraction and harden it through complete hydrogenation. One stage dry fractionation yielded 37% of softer or 24% of harder stearin fraction. Two stages dry fractionation yielded 24% harder and 11% softer stearin fractions. Even though two stages dry fractionation salvaged up to 14% of the softer stearin fraction from the normally discounted palm kernel olein fraction, the double fractionation process was not always commercially feasible. Deciphering actual price statistics revealed that on a per metric tonne basis, the refining premium ranged from MYR90 to 250. Palm kernel olein discount was as high as 9% but could command premium over crude PKO by up to 2.5%. Due to the intrinsic relationship, the corresponding palm kernel stearin breakeven value could range from discount of MYR90 to premium of MYR1260 over crude PKO. The actual 60 months average market premium for palm kernel stearin stood at MYR870, promising an average MYR430 returns to refiners and processors. By incorporating two stages dry fractionation when the PKL discount was greater than 2.43%, refiners and processors could boost their net margins. When the PKL discount was 9%, the net margin could be boosted by up to 16%.

Physicochemical properties and crystallisation behaviour of bakery shortening produced from stearin fraction of palm-based diacyglycerol blended with various vegetable oils

The stearin fraction of palm-based diacylglycerol (PDAGS) was produced from dry fractionation of palm-based diacylglycerol (PDAG). Bakery shortening blends were produced by mixing PDAGS with either palm mid fraction, PMF (PDAGS/PMF), palm olein, POL(PDAGS/POL) or sunflower oil, SFO (PDAGS/SFO) at PDAGS molar fraction of XPDAGS=0.4%, 0.5%, 0.6%, 0.7%, 0.8%, 0.9%. The physicochemical results obtained indicated that C16:0 and C18:1 were the dominant fatty acids for PDAGS/PMF and PDAGS/POL, while C18:1 and C18:2 were dominant in the PDAGS/SFO mixtures. SMP and SFC of the PDAGS were reduced with the addition of PMF, POL and SFO. Binary mixtures of PDAGS/PMF had better structural compatibility and full miscibility with each other. PDAGS/PMF and PDAGS/SFO crystallised in β′+β polymorphs in the presence of 0.4–0.5% PDAGS while PDAGS/POL resulted in β polymorphs crystal. The results gave indication that PDAGS: PMF at 50%:50% and 60%:40% (w/w) were the most suitable fat blend to be used as bakery shortening.

Palm-based diacylglycerol fat dry fractionation: effect of crystallisation temperature, cooling rate and agitation speed on physical and chemical properties of fractions

Fractionation which separates the olein (liquid) and stearin (solid) fractions of oil is used to modify the physicochemical properties of fats in order to extend its applications. Studies showed that the properties of fractionated end products can be affected by fractionation processing conditions. In the present study, dry fractionation of palm-based diacylglycerol (PDAG) was performed at different: cooling rates (0.05, 0.5, 1.0, 1.5, 2.0, 2.5 and 3.0°C/min), end-crystallisation temperatures (30, 35, 40, 45 and 50°C) and agitation speeds (30, 50, 70, 90 and 110 rpm) to determine the effect of these parameters on the properties and yield of the solid and liquid portions. To determine the physicochemical properties of olein and stearin fraction: Iodine value (IV), fatty acid composition (FAC), acylglycerol composition, slip melting point (SMP), solid fat content (SFC), thermal behaviour tests were carried out. Fractionation of PDAG fat changes the chemical composition of liquid and solid fractions. In terms of FAC, the major fatty acid in olein and stearin fractions were oleic (C18:1) and palmitic (C16:0) respectively. Acylglycerol composition showed that olein and stearin fractions is concentrated with TAG and DAG respectively. Crystallization temperature, cooling rate and agitation speed does not affect the IV, SFC, melting and cooling properties of the stearin fraction. The stearin fraction was only affected by cooling rate which changes its SMP. On the other hand, olein fraction was affected by crystallization temperature and cooling rate but not agitation speed which caused changes in IV, SMP, SFC, melting and crystallization behavior. Increase in both the crystallization temperature and cooling rate caused a reduction of IV, increment of the SFC, SMP, melting and crystallization behaviour of olein fraction and vice versa. The fractionated stearin part melted above 65°C while the olein melted at 40°C. SMP in olein fraction also reduced to a range of 26 to 44°C while SMP of stearin fractions increased to (60–62°C) compared to PDAG.

Multivariate Characterization of Milk Fat Fractions by Gas Chromatography

A high-speed gas chromatography method has been developed to separate the fatty acids in different milk fat fractions obtained via the dry fractionation deodorization process (TIRTIAUX method). Exploratory data techniques, namely cluster analysis and principal component analysis (PCA), were applied to gas chromatographic data for fatty acids composition in these milk fractions. Cluster analysis allowed the authors to visualize natural groupings corresponding to milk fat cracking achieved via the TIRTIAUX method. Principal component plots showed that six fractions are grouped in different classes, each group being clearly distinguished. Furthermore, a relationship was established between these classes and fatty acids through PCA analysis. A discriminant linear model for predicting milk fat classes from fatty acid composition was computed; 99 % of the criterion variable (milk fat class) variance was explained by the constructed model. Enrichment in unsaturated cis-fatty acids in the olein fractions and in the saturated and unsaturated trans-fatty acids in the stearin fractions was visualized from chemometric analysis. This differentiation of the milk fat fractions on the basis of fatty acids composition will enable food industries to use these fractions in both an efficient and safe way to enrich dairy products, or other foods, for healthy consumption.

Characterization of the Stearin Obtained by Thermal Fractionation of Anhydrous Milk Fat

Thermal fractionation of anhydrous milk fat with high initial content of low molecular weight TAGs was performed based on a 2 2 factorial experimental design with three central and two axial points. The independent variables were the crystallization temperature and the cooling rate. A 2.0 L agitated glass reactor was used and the rotation was kept at 20 rpm. The filtration was performed under vacuum (500 mmHg), using a 14 μm average pore diameter filter paper. Curves of isothermal crystallization of the stearin fraction showed that increasing the crystallization temperature, increases the induction period and decreases the maximum solid content of stearin. An increase of the crystallization temperature resulted in an increase in solid fat content. All runs achieved an efficient fractionation using a single separation step and stearin with defined characteristics can be obtained adapting the process conditions.

Calorimetric study of milk fat/rapeseed oil blends and their interesterification products

AbstractMilk fat (MF) and rapeseed oil (RO) blends were analyzed by differential scanning calorimetry (DSC). It was shown that peak and onset temperatures can be used to determine the percentage of each fat in the blend and that the relative enthalpy of one peak assigned to low‐melting triacylglycerols (TAG) can also be used to determine the percentage of RO in the blend. A linear relation was also established between MF content of the blend and its dropping point (DP), indicating that DP can be linearly related with the above DSC data. A blend of MF/RO 70 : 30 (wt/wt) was then chosen as a model system for enzymatic interesterification (EIE). The applicability of DSC analyses to EIE products was checked and a correct correlation could be established between DSC values and the interesterification degree and DP. Among the data from the DSC profiles, the peak associated with low‐melting TAG was the best indicator of the reaction course. In the same way, a high‐melting MF stearin fraction was interesterified with RO. In that case, onset temperatures and peak “a” were better reaction indicators than for the interesterified MF/RO blend. We therefore suggest that values from DSC endotherms could be used to monitor EIE of fat blends.

Chicken fat dry fractionation: Effects of temperature and time on crystallization, filtration and fraction properties

AbstractA surface response experimental design was used to quantify the effects of the final cooling temperature and the residence time at this temperature on the filtration characteristics of the crystal suspension and the quality of the fractions during chicken fat dry fractionation. The crystal morphology was monitored to gain insight into the observed effects. Temperature affected crystallization and the characteristics of the olein and stearin fractions. The crystals became fragmented as the residence time increased, thus leading to a decrease in the filterability of the crystal suspension and an increase in the proportion of the entrained liquid phase. The residence time only affected the quality of the stearin fraction. This time effect was noted at high cooling temperatures in the investigated experimental domain. At low temperatures, increasing the residence time enhanced crystal growth and increased the extent of unsaturation of both fractions without modifying the filtration features.