Physical Properties of Cocoa Butter/Vegetable Oil Blends Crystallized in a Scraped Surface Heat Exchanger

Blends of cocoa butter with soybean oil (CB/SO) or canola oil (CB/CO) were crystallized at either of two agitation rates (100 or 1,000 rpm) and at two process temperatures (14 or 17 °C) in a scraped surface heat exchanger (SSHE). The physical properties were characterized at the SSHE output and during storage (14 and 28 days) at 15 °C. At the SSHE output, the CB/CO and CB/SO systems that had been processed at 100 rpm presented a more solid-like character than systems processed at 1,000 rpm despite the fact that the former systems contained a higher solid fat content than the latter. The degree of secondary crystallization increased with increasing shear rate. Nevertheless, the polymorphic behavior of cocoa butter crystals resembled the behavior observed under static isothermal crystallization conditions. At the SSHE output, systems of either blend contained a mixture of β′ and β crystals. During storage, β′ converted to β in both blends, although it did so to a higher extent in the CB/CO systems. Crystal ripening, observed in the CB/CO blend, provided stability to the systems during storage. In contrast, the CB/SO system increased its hardness by a slow sintering process. The polymorphism and hardness evolution in the blends under study were found to be associated with the molecular compatibility of the triacylglycerols in the cocoa butter and the vegetable oils tested.     

Tailoring Crystalline Structure Using High-Intensity Ultrasound to Reduce Oil Migration in a Low Saturated Fat

The objective of this study was to use high-intensity ultrasound (HIU) to change the crystalline structure of an interesterified soybean oil (IESBO) with 33% of saturated fats and to evaluate how these changes affect oil migration. The IESBO was crystallized at different temperatures (26, 28, 30, and 32 °C) with and without HIU. Results show that oil migration was significantly affected by HIU (P < 0.05). HIU promoted crystallization and induced the formation of harder crystalline networks that were more resistant to oil migration with lower melting peak temperatures and sharper melting profiles. Samples processed with HIU had fewer crystalline clusters as observed by microscopy. Changes observed on the physical properties of the IESBO due to sonication that consequently improved oil migration were attributed to the ability of HIU to induce secondary nucleation and crystallize low-melting point triacyclglycerols (SUU) that would not crystallize without the HIU and to the stronger and stable crystalline network formed capable of entrapping liquid TAG (UUU).     

Effects of Ultrasonic Parameters on the Crystallization Behavior of Palm Oil

The crystallization behavior of palm oil (PO) without and with the application of high-intensity ultrasound (HIU) was investigated as the function of irradiation time (20, 60, 120, and 240 s), ultrasonic intensity (47.5, 95, 270, and 475 W) and temperature (20, 25, 30, and 36 °C). The effects on the crystallization behavior of PO were evaluated by ultraviolet/visible spectrophotometry, pulsed nuclear magnetic resonance and polarized light microscopy. Results indicated that all these parameters affected crystallization behavior. HIU significantly reduced the induction time and accelerated the crystallization rate at operating temperatures above 25 °C, but there was no significant difference at 20 °C due to high supercooling. The effects of HIU were more significant at higher power level and longer irradiation time, however, the thermal effect of ultrasound also increased with longer sonication time. The optimal sonication time was approximately 120 s which accelerated the crystallization rate of PO the most. The morphology studies suggested that HIU changed the growth mechanisms of crystals and generated smaller and uniformly crystals. At 36 °C, with extremely low supercooling condition, a combined effect was observed that prevented the separation of solid phase and liquid phase of the crystallized sample, and then led to a uniform distribution of crystals.     

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

The objective of this research was to evaluate the effect of high‐intensity ultrasound (HIU) and crystallization temperature (T_c) 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 T_c. SFC values were fitted using the Avrami model, and higher k_n 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.     

Effects of High Intensity Ultrasound Frequency and High-Speed Agitation on Fat Crystallization

The objective of this research was to examine the effect of ultrasound frequency and high-speed agitation on lipid crystallization. Interesterified soybean oil was crystallized at 44 °C without and with the application of high intensity ultrasound (HIU—20 and 40 kHz) or with high-speed agitation (6000 and 24,000 rpm). Two tip amplitudes (24 and 108 µm) and three pulse durations were evaluated (5, 10, and 15 s) for the acoustic frequencies tested. Sonication at 20 kHz of frequency significantly reduced crystal size, increased (p < 0.05) elasticity (435.9 ± 173.3–80,218 ± 15,384 Pa) and SFC (0.2 ± 0.0–4.5 ± 0.4%). No significant difference was observed in the crystallization behavior of these samples when sonicated at different amplitudes for 5 and 10 s. The crystallization behavior was significantly delayed (p < 0.05) in samples sonicated using 108 µm amplitude for 15 s. Larger crystals were formed in samples sonicated at 40 kHz compared to those obtained with 20 kHz and lower SFC (3.7 ± 0.0%) and elasticity (3943 ± 1459 Pa) values were obtained. High-speed agitation at 24,000 rpm increased SFC (5.5 ± 0.1%) and crystallized area and decreased the elasticity (42,602 ± 11,775 Pa) compared to the samples sonicated at 20 kHz.     

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.     

Application of High Intensity Ultrasound to a Zero-trans Shortening During Temperature Cycling at Different Cooling Rates

The objective of this work was to evaluate the effect of high intensity ultrasound (HIU) on the physical properties of a commercial shortening crystallized at a constant temperature and during temperature cycling at two different cooling rates (0.5 and 1 °C/min). Different ultrasound power levels and different durations were evaluated during crystallization at a constant temperature and the best conditions were used to evaluate the effect of HIU during temperature cycling. The physical properties tested were crystal microstructure, viscoelasticity, and melting profile. Results show that HIU is more efficient at changing crystal microstructure when used at 20 °C using a 1/2″ tip. No difference was found on the microstructure of the crystals formed when different durations of ultrasound exposure were tested. A significant increase (p < 0.05) was observed in the storage modulus (G′) of the lipid exposed to temperature fluctuations with the use of HIU. The G′ values increased from 662.6 ± 176.8 Pa (no HIU applied) to 3,365.5 ± 426.4 Pa (with HIU applied, 0.5 °C/min) and from 354.4 ± 49.7 Pa (no HIU applied) to 1,249.0 ± 19.8 Pa (with HIU applied, 1 °C/min).     

Sonocrystallization of Interesterified Soybean Oil With and Without Agitation

Interesterified soybean oil was crystallized at 29, 34, and 35 °C with and without the use of high‐intensity ultrasound. Samples were crystallized using either (1) continued agitation for the entire crystallization process (CA) or (2) agitation for 10 min (A10) followed by static crystallization. Sonication and agitation decreased the induction period of nucleation at higher temperatures and changed the crystal morphology, crystallization kinetics, and viscoelasticity of the sample. Sonication reduced the crystal sizes and significantly (P <0.05) increased the viscosity (5.2 ± 1.2 to 2369.6 ± 712.1 Pa s) and elastic modulus (83.2 ± 4.1 to 69,236.7 ± 26,765 Pa) of the crystalline networks obtained at 29 °C under A10 condition. An increase in viscosity and elasticity was also observed for sonicated samples crystallized at 34 and 35 °C under A10 and all CA conditions but these differences were not statistically significant (P >0.05). Sonication increased crystallization rates for all conditions tested. Kinetic constants obtained from an Avrami fit increased from1.3 × 10^?5 to 6.8 × 10^?5 min^?n for samples crystallized at 29 °C A10 without and with sonication, respectively, and from 2.6 × 10^?9 to 2.4 × 10^?7 min^?n for samples crystallized at 34 °C A10 without and with sonication, respectively. This increase in the crystallization rate was also observed for samples crystallized under the CA condition at 29 °C.     

Relationship between oil binding capacity and physical properties of interesterified soybean oil

The objective of this study was to identify the physical properties of an interesterified soybean oil (EIESOY), containing 45% saturated fatty acids (SFA), that correlates with high oil binding capacity (OBC) and low oil loss (OL). In this study, three EIESOY samples were analyzed; a 100% sample, a 50% sample diluted with 50% soybean oil, and a 20% sample diluted with 80% soybean oil. All samples were crystallized using fast (7.78°C/min) and slow (0.1°C/min) cooling rates as well as with and without high-intensity ultrasound (HIU, 20 kHz). The 100%, 50%, and 20% samples were crystallized at 38.5, 27.0, and 22.0°C, respectively. HIU was applied at the onset of crystallization and all samples were allowed to crystallize isothermally for 90 min. After 90 min, physical properties such as crystal microstructure, hardness, solid fat content (SFC), elasticity, and melting behavior were evaluated. Physical properties were also measured after storage for 48 h at 22 and 5°C. Results show that OBC was positively correlated with hardness, G′, and SFC after 48 h (r = 0.738, p = 0.006; r = 0.639, p = 0.025; r = 0.695, p = 0.012; respectively), OL was negatively correlated with hardness after 48 h (r = −0.696, p < 0.001), G′ after 90 min and 48 h (r = −0.704, p < 0.001; r = −0.590, p = 0.002), and SFC after 90 min and 48 h (r = −0.722, p < 0.001; r = −0.788, p < 0.001). Neither OBC nor OL were correlated with crystal diameter or the number of crystals.     

Sonocrystallization of a Tristearin‐Free Fat

The objective of this study was to fractionate a purified interesterified fat to eliminate tristearin (SSS) and to evaluate the crystallization behavior of the tristearin‐free fat. The fractionated sample was crystallized with and without the application of high‐intensity ultrasound (HIU) by supercooling the sample at 2 °C. In the absence of SSS, the crystallization process was driven by low‐melting‐point triacylglycerols (TAG) such as OSS and OOS (O, oleic; S, stearic acid). There were no differences observed in the crystallinity in the sample based on the solid fat content (P > 0.05) along with any microstructural differences. In addition, an increase in the enthalpy of melting was observed upon sonication, indicating higher crystallinity (P < 0.05). Stronger intramolecular forces were formed in the sonicated samples as evidenced by increased viscoelastic parameters such as the elastic modulus (G′) and storage modulus (G″) (P < 0.05). G′ values increased from 138.25 ± 41.30 to 939.73 ± 277.45 Pa while the G″ values increased from 39.15 ± 8.98 to 149.77 ± 16.00 Pa (P < 0.05). Change in viscosity was not observed as a consequence of sonication (P > 0.05). This study showed that HIU was effective in changing the crystallization behavior of SSS‐free fats with low‐melting TAG.     

销钉机筒挤出机塑化段传热温度模型研究

通过建立简化的销钉机筒挤出机塑化段物理模型，从流变分析中的能量方程出发，导出销钉机筒挤出机塑化段温度的传热模型；结合试验数据，拟合出挤出温度随螺杆转速变化的曲线。结果表明，曲线可分为急速增长段、平缓增长段和稳定增长段3部分，且平缓增长段是挤出温度、质量和能耗综合指标最佳的区间。     

Effect of High Intensity Ultrasound on Crystallization Behavior of Anhydrous Milk Fat

The need to eliminate trans-fatty acids from foods’ formulation resulted in the exploration of new lipid sources and alternative processing conditions that will improve the physicochemical characteristics and nutritional qualities of lipid-based foods. In general, the physicochemical characteristics of lipid networks depend on the microstructure and crystallization behavior of the system. The objective of this work was to use high intensity ultrasound (HIU) as an additional processing condition to alter the crystallization behavior of a lipid model system (anhydrous milk fat). Results show that HIU application not only decreases the induction time of crystallization (faster crystallization) at a constant crystallization temperature, but also generates smaller crystals. In addition, higher viscosities are obtained when samples are crystallized after HIU application. The degree of supercooling, ultrasound application settings and a combination of both parameters influence the degree of ultrasound effect on the crystallization behavior.     

Sonocrystallization of Interesterified Fats with 20 and 30% C16:0 at <Emphasis Type="Italic">sn</Emphasis>-2 Position

The objective of this study was to induce crystallization in enzymatically interesterified fats (IE) with 20 and 30% palmitic acid at the sn-2 position using high intensity ultrasound (HIU). The physical blends (PB) used to prepare these two IE were consisted of tripalmitin and high oleic sunflower oil and contained 13.2 and 27.1% tripalmitin, respectively. Crystallization behavior of IE was compared with PB at supercoolings of 9, 6 and 3 °C. Results show that the melting point, SFC, and crystallization rate of PB were higher than IE and were driven mainly by tripalmitin content. HIU induced crystallization and generated small crystals in the IE samples. At 9 °C supercooling, sonication did not increase the viscosity of IE C16:0 20%, while that of the IE C16:0 30% increased significantly from 192.4 ± 118.9 to 3297.7 ± 1368.6 Pa·s. The elastic modulus (G’) for IE C16:0 30% increased from 12521 ± 2739.8 to 75076.7 ± 18259 Pa upon sonication at 9 °C supercooling, while the G’ of the IE C16:0 20% did not increase. Similar behavior was observed for the other supercoolings tested. This research suggests that HIU can improve the functional properties of IE with low content of C16:0 creating more viscous and elastic materials. These fats with low C16:0 content and improved functional properties could be used as trans-free fat alternatives.     

Enhanced hydrate formation under mild conditions using a novel spiral-agitated reactor

Hydrate-based solidified natural gas (SNG) technology provides a promising approach to store and transport natural gas, but demanding formation conditions and low methane storage capacity limit its application. Here, we presented a novel spiral-agitated reactor, and hydrate formation in pure water and amino acid systems was evaluated. It is worth to highlight that spiral agitation significantly enhances initial hydrate grow kinetics, and satisfied methane uptake of 134.9 V/V was obtained under a mild condition (4.3 MPa, 275.15 K, and 30 rpm). Impressively, when amino acids were introduced, late hydrate growth was greatly improved because of secondary uptake, and a large methane uptake (145.97 V/V) was obtained under a milder condition (3.8 MPa, 275.15 K, and 60 rpm), which increases by 82.97% comparing to that in pure water systems. These findings provide a new insight (synergistic effect of spiral agitation and amino acids) on enhanced hydrate production under extremely mild conditions.     

Preparation and characterization of two-way shape memory olefin block copolymer/silicone elastomeric blends

Very few olefin block copolymer (OBC)-based shape memory polymers (SMPs) studies were reported in the literature so far. This study investigated the preparation of OBC and silicone elastomeric blends (70/30 and 50/50) using a melt-blending technique to form the first two-way OBC-based SMPs, to our best knowledge. Two phr of ((2,5-bis(tert-butylperoxy)-2,5-dimethylhexane (DHBP) was used to prepare flexible OBC/silicone D2 (D2 representing 2 phr of DHBP) networks. DHBP not only assisted the curing of OBC and silicone but also increased their compatibility in the blends. Despite the very low crystallinity of the OBC elastomer component, 10.4%, corresponding to only ~7% based on total resins in the OBC/silicone D2 70/30 blend, the rare two-way shape memory behavior at such a low crystallinity was still envisaged. Regarding two-way shape memory results at various loads, both entropy-driven and crystallization-driven contributions to the overall actuation magnitude (R_act) were at the highest level under 450 kPa, attributing to the highest orientation of molecular networks in the blends. With increasing the applied stress, the R_act of OBC/silicone (70/30) sample increased from 4.1% to 23.7% due to the increased strain-induced crystallization effect confirmed by the XRD (X-ray diffraction) evaluation, while the recovery magnitude (R_rec) was maintained at the high level, close to 90%, without the hindrance of high load on the recovery due to high elasticity of silicone rubber. Besides, the crystallization-driven contribution to the overall actuation magnitude was higher for the blends containing the higher amount of crystalline OBC elastomer in the blends. On behalf of silicone with outstanding thermal stability, high elastic behavior, and high hydrophobicity, OBC/silicone SMP blends with versatile properties could meet different applications.     

Impact of high-intensity ultrasound on physical properties and degree of oxidation of lipase modified menhaden oil with caprylic acid and/or stearic acid

The purpose of this research was to determine the effect of high-intensity ultrasound (HIU) on physical properties, degree of oxidation, and oxidative stability of structured lipids (SLs). Caprylic acid (C) and stearic acid (S) were incorporated into menhaden oil using Lipozyme® 435 lipase to obtain five samples: (1) LC 20 (menhaden oil with 20% of C), (2) LC 30 (menhaden oil with 30% C), (3) LS 20 (menhaden oil with 20% S), (4) LS 30 (menhaden oil with 30% S), and (5) Blend C (menhaden oil with 16.24% C and 13.04% S). Samples were crystallized for 90 min at the following temperatures: (1) LC 20 at 15.5°C, (2) LC 30 at 17.5°C, (3) LS 20 at 24°C, (4) LS 30 at 30°C, and (5) Blend C at 18.0°C, and HIU was applied at the onset of crystallization. Physical properties, degree of oxidation, and oxidative stability were evaluated in sonicated and nonsonicated samples. All SLs had statistically higher G′ after sonication. Sonicated LS 30, LC 30, and Blend C had a higher melting enthalpy than the nonsonicated ones, while enthalpy values in sonicated LS 20 and LC 20 samples were not statistically different than the nonsonicated ones. No significant difference between sonicated and nonsonicated samples was observed in peroxide values (1.2 ± 0.1 meq/kg, p > 0.05) and in the oxidative stability index (6.3 ± 0.2 h, p > 0.05). These results showed that HIU was effective at changing physical properties without affecting the oxidation of the samples.     

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

Physical 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.     

Use of High-Intensity Ultrasound to Change the Physical Properties of Oleogels and Emulsion Gels

The objective of this work was to evaluate the effect of high-intensity ultrasound (HIU) on the physical properties of a soft oleogel (2% of candelilla wax, 2% of monoacylglycerol, and 2% of hardfat) and of water-in-oil (W/O) emulsion gels (EG) with various amounts of water (0%, 5%, and 25%). Physical properties of these systems such as thermoresistance, microstructure, melting profile, hardness, rheology, and oil loss were measured. When HIU was applied to the oleogel for 3 min using a 3.2 mm-diameter tip at an amplitude of vibration of 216 μm, a reduction in crystal size and crystal area (P < 0.05) was observed with an increase in hardness and no change in G′ nor in oil loss compared to the nonsonicated oleogel. Other sonication conditions (lower power levels, shorter durations, and bigger tips) tested in this study reduced the hardness and elasticity of the sample and increased oil loss. When HIU (3.2 mm-diameter tip, 216 μm, 3 min) was used in emulsions, harder and more elastic (P < 0.05) samples were obtained only in the samples with 25% water. This study shows that the texture of oleogels and EG with 25% of water can be improved by using HIU. The impact of these results is that the fat content of an EG can be reduced by 25% by adding water and HIU can be used to recover the structure lost due to water addition.     

Influence of Processing Conditions on the Physicochemical Properties of Complex Fat Systems

Three blends of soybean oil (SBO), coconut oil (CO), and palm stearin (PS) were crystallized at different shear rates (100 and 1,000 rpm) and processing temperatures (low and high) in a scraped surface heat exchanger. The SBO/CO/PS proportions (w/w) tested were 50/0/50 %, 33/33/33 %, and 16.7/16.7/66.6 %. The physicochemical properties of the blends were analyzed by differential scanning calorimetry, texture analysis, microscopy, and the released oil (Ro) technique. The blends crystallized at 100 rpm developed two endotherms, which were associated with β and co-crystallized β′. In contrast, only the β′ polymorph was observed in blends processed at 1,000 rpm. After 28 days, the presence of β crystals and medium-chain TAG in the blends appeared to stimulate a transition of phase from β′ to β. In general, the hardness of the blends was directly related to the concentration of PS. The systems that were crystallized at 1,000 rpm demonstrated higher hardness, adhesiveness, and crystalline stability than those crystallized at 100 rpm. At both processing temperatures investigated, the blends with the highest Ro and permeability were obtained at 1,000 rpm. These characteristics were associated with the agglomeration of saturated TAG and were promoted by the initial crystallization conditions and migration of TAG during storage. At shear rates of 1,000 rpm and a PS concentration range of 50–66.6 %, the Ro of the blends was 2–10 % with a lower solid fraction, an important signal of good stability.     

Effect of Lactose Monolaurate and High Intensity Ultrasound on Crystallization Behavior of Anhydrous Milk Fat

Crystallization behavior of anhydrous milk fat (AMF) was studied with the addition of 0.025 and 0.05 % lactose monolaurate (LML). The crystallization behavior was studied at low (ΔT = 3 °C) and high supercooling (ΔT = 6 °C). Polarized light microscopy and laser turbidimetry indicated a delay in crystallization on addition of 0.025 % and 0.05 % LML or Tween 20 to AMF. High intensity ultrasound (HIU) was applied to AMF samples with 0.05 % LML and lower supercooling (T _c = 31 °C; ΔT = 3 °C). HIU application in AMF and AMF + 0.05 % LML induced crystallization (p < 0.05) changing the induction time (τ) at 31 °C from 34.20 ± 1.67 min (AMF) and 47.07 ± 1.27 min (AMF + 0.05 % LML) to 23.23 ± 3.26 min (AMF) and 25.00 ± 0.87 min (AMF + 0.05 % LML). Melting enthalpies (ΔH) of AMF were significantly higher (p < 0.05) than the ones observed for AMF + 0.05 % LML when crystallized without HIU, while enthalpy values increased significantly in AMF + 0.05 % LML samples when crystallized with HIU reaching similar values to the ones obtained for AMF without LML. The viscosity of AMF significantly decreased (p < 0.05) on addition of 0.05 % LML and significantly increased on HIU application.