Characterization and fat migration of palm kernel stearin as affected by addition of desiccated coconut used as base filling centre in dark chocolate

The characterization and fat migration of palm kernel stearin (PKS) and desiccated coconut, used as base filling centre in dark chocolate were studied. C36 and C38 triglycerides of PKS decreased by 11% and 9.6% respectively, whereas C32 and C34 increased by 97% and 48% respectively. The change in the triglycerides composition of PKS shift the melting point of PKS from 33.2 to 31.4°C. Solid fat content (SFC) of PK reduced by 40% at 30°C. The rate of fat migration was very slow at 18°C storage compared to 30°C. The rate of change of C36 in the chocolate layer was 0.1% week-1 and 1.2% week-1 at 18 and 30°C respectively. Chocolate stored at 18°C showed post hardening during storage period and withstood bloom during the storage period, whereas that stored at 30°C became soft and bloomed faster after 3 weeks of storage

Use of palm mid-fraction in dark chocolate as base filling centre at different storage temperatures

Dark chocolates filled with palm mid-fraction (PMF) were stored at different temperatures to evaluate the physical and chemical changes. Storage at low temperature (18°C) reduces the PMF migration to negligible extent. Higher storage temperatures (30 and 35°C) increased the PMF migration from the filling centre into the chocolate coating. As a consequence of fat migration, fatty acid composition, triglyceride composition, hardness, solid fat content, melting point and polymorphic structure changed, leading to bloom formation, which started by fat migration and was influenced by recrystallization tendency within the chocolate coating

Effect of storage temperature on texture, polymorphic structure, bloom formation and sensory attributes of filled dark chocolate

The effects of 18 and 30°C storage temperatures on texture, polymorphic structure, bloom formation and sensory attributes of dark chocolate, stored for 8 weeks were studied. Results showed that storage at 18°C for 8 weeks, significantly retarded changes in filled chocolates; the chocolates were free from bloom during the storage period. In contrast, at 30°C there was an increase in the rate of fat migration and rate of change of C36 and C50, and also a decrease in texture and the polymorph structure in the coating changed to β and β′ polymorphs. However, the chocolates bloomed in the third week of storage (2 cycles). Sensory evaluation indicated that, storage at 18°C is better than 30°C, and desiccated coconut gives a pleasant flavour to the chocolate

Monitoring crystal development in palm oil-based fluid shortening production by FT-IR spectroscopy

The extent of crystal development of palm oil-based fluid shortening was determined using attenuated total reflectance (ATR) of Fourier transform infrared (FT-IR) spectroscopy. The molten fat was cooled, heated and cooled again while agitating at constant speed. Samples for solid fat content (SFC) measurements by nuclear magnetic resonance (NMR) and FT-IR spectroscopy were taken during the crystallization process at 20C and heating process at 30C. Standards producing the best coefficient of determination (R. 2) and standard error of estimation for each temperature, calibrated with the spectrum obtained by FT-IR spectroscopy using partial least square (PLS) chemometric analysis, were selected as the PLS model. The model was independently validated by the " leave one out" method. The model accuracy and repeatability was good with a R. 2> 0.9 at 20 and 30C, thus providing good SFC estimates during the production of palm oil-based fluid shortening. The advantage of this method is that it mainly reduces the tedious sample preparation needed for the NMR measurement

Oxidative stability of palm - and soybean-based medium- and long-chain triacylglycerol (MLCT) oil blends

BACKGROUND: Medium- and long-chain triacylglyerols (MLCT) enzymatically esterified using Lipozyme RM IM lipase has very low oxidative stability as it does not contain any antioxidants. The aim of this work was to study the ability of various antioxidants to increase the oxidative stability of palm- and soybean-based MLCT blends which assist to bring up the oxidative stability of both MLCT blends. In this study, the effectiveness of rosemary extracts, sage extracts, tert-butylhydroquinone (TBHQ) and mixtures of tert-butyl-4-hydroxyanisole (BHA) and tert-butyl-p-hydroxytoluene (BHT) in protecting against oxidation of various MLCT blends was investigated. RESULTS: Blending of MLCT oil with either palm olein or soybean oil improved its smoke point values and oxidative stability. TBHQ addition to both palm- and soybean-based MLCT blends increased oxidative stability. Combination of BHA and BHT showed no significant improvement (P > 0.05) in ability to protect blends from oxidation compared to natural antioxidants such as sage or rosemary extracts. CONCLUSION: Blended oils with 500 g kg−1 MLCT and 500 g kg−1 palm olein (MP5) were the most suitable for use at high temperature based on the fatty acid composition of the MLCT blends, which subsequently had an effect on thermal oxidative stability. In general, addition of either natural or synthetic antioxidant assisted in improving the antioxidative strength of both MLCT blends. MLCT blends with added TBHQ showed the highest thermal oxidative stability among the antioxidants used. Copyright © 2008 Society of Chemical Industr

Deep frying performance of enzymatically synthesised palm-based medium- and long-chain triaclyglycerols (MLCT) oil blends

The main aim of this work was to assess the frying strength of the enzymatically synthesized palm-based medium- and long-chain triacylglycerols (MLCT) oil with the aid of different antioxidants under deep-frying conditions. Palm-based MLCT oil in the presence of synthetic or natural antioxidants showed significantly better(P0.05) in the saturated/unsaturated fatty acids ratio across frying periods indicated good oxidative stability of the palm-based MLCT oil. Due to the polarity of medium- and long-chain triacylglycerols in palm-based MLCT oil, total polar compounds determination may not be a suitable oil quality measures. Sensory evaluation of fried chips showed no significant differences (P>0.05) between chips fried in RBD palm olein and palm-based MLCT oil over the 3-month storage period

The use of enzymatically synthesized medium– and long-chain triacylglycerols (MLCT) oil blends in food application

The potential use of medium- and long-chain triacylglycerols (MLCT) oil blends in food applications such as frying oil and salad dressings were investigated. The frying strength of palm-based MLCT oil with different antioxidants under deep frying conditions was assessed. Palm-based MLCT oil showed better thermalresistant oxidative strength than refined, bleached and deodorized (RBD) palm olein throughout the five consecutive days of frying. Sensory evaluation and rancidity assessment on fried chips showed no significant differences (P > 0.05) between chips fried in RBD palm olein and palm-based MLCT oil. MLCT-based salad dressings treated with different antioxidants showed similar rheological behaviors as compared to soybeanbased salad dressings. The overall quality of the physical appearance and organoleptic acceptability based on quantitative descriptive analysis showed no significant differences (P > 0.05) in all salad dressings. These findings indicated that MLCT-based oil blends can be used as healthy functional oil for daily consumption

Rheological properties, oxidative stability and sensory evaluation of enzymatically synthesized medium- and long-chain triacylglycerol-based salad dressings

The rheological properties of various oil-based salad dressings were investigated. The shear rate-shear stress study based on Power Law's model indicated pseudoplastic fluid behaviors of dressings prepared in this study. Soybean- and medium- and long-chain triacylglycerols (MLCT)-based dressings treated with different antioxidants showed similar rheological behaviors based on the changes in the storage modulus, loss modulus, viscosity profile and loss tangent in the frequency, amplitude and temperature sweep study. The time-dependent study revealed similar thixotrophic properties between soybean- and MLCT-based dressings. Addition of synthetic or natural antioxidants reduced the rate of oil deterioration in oil-in-water emulsion as a function of time. No significant differences (p >0.05) in hydrolytic reaction of all dressing systems were observed throughout the 3 months of storage at 20 °C. Quantitative descriptive analysis using trained panelists revealed no significant differences (p >0.05) either in salad oils or salad dressings except for MLCT-based oils/dressings treated with oleoresin sage extracts, which showed darker and stronger odor intensity than other oil systems. Nevertheless, the overall quality of the physical appearance and organoleptic acceptability showed no significant differences (p >0.05) in all systems, indicating that MLCT-based blends can be used as healthy functional oils to replace soybean oil in food dressing applications

Diacylglycerol and Triacylglycerol as Responses in a Dual Response Surface-Optimized Process for Diacylglycerol Production by Lipase-Catalyzed Esterification in a Pilot Packed-Bed Enzyme Reactor

Diacylglycerol (DAG) and triacylglycerol (TAG) as responses on optimization of DAG production using a dual response approach of response surface methodology were investigated. This approach takes the molecular equilibrium of DAG into account and allows for the optimization of reaction conditions to achieve maximum DAG and minimum TAG yields. The esterification reaction was optimized with four factors using a central composite rotatable design. The following optimized conditions yielded 48 wt % DAG and 14 wt % TAG: reaction temperature of 66.29 °C, enzyme dosage of 4 wt %, fatty acid/glycerol molar ratio of 2.14, and reaction time of 4.14 h. Similar results were achieved when the process was scaled up to a 10 kg production in a pilot packed-bed enzyme reactor. Lipozyme RM IM did not show any significant activity losses or changes in fatty acid selectivity on DAG synthesis during the 10 pilot productions. However, lipozyme RM IM displayed higher selectivity toward the production of oleic acid-enriched DAG. The purity of DAG oil after purification was 92 wt %