منبسط کنندگان کره کاکائو مقاوم به حرارت از چربی های Mahua Madhuca (لافیولیا) و کاکوم (گارسینیای هندی) Heat-Resistant Cocoa Butter Extenders from Mahua (Madhuca latifolia) and Kokum (Garcinia indica) Fats

(i) Solvent fractionation. Mahua fat (200 g) was dissolved in 200 mL of acetone by heating to 50°C. The solution was gradually cooled to 13°C and held at this temperature for about 3 h with occasional stirring. The partially crystallized mass was filtered to separate stearin and olein fractions. The solvent from the stearin fraction was removed under vacuum and the yield was 35%. Mahua and kokum fats were mixed in a 1:1 ratio (w/w) and heated to 50°C to get a clear liquid. The blend (200 g) was dissolved in 400 mL of acetone. The solution was gradually cooled to 18°C and held at this temperature for 3 h with occasional stirring and then filtered. The solvent from the stearin [yield 77–۸۰%, Fraction (Fr.) 1] was removed under vacuum. (ii) Dry fractionation. Mahua and kokum fats were mixed in equal proportions and heated to 55°C to get a clear liquid. The blend (200 g) was gradually cooled to 27°C and held at this temperature for 2 h with occasional stirring. The stearin (yield 77%, Fr. 2) was removed by filtration under vacuum by manually pressing the material from above. Differential scanning calorimetry (DSC). A Mettler (Griefensee, Switzerland) TA-3000 DSC system was used to obtain melting endotherms and melting profiles along with the percent liquids at various temperatures. The heat flow of the instrument was calibrated using indium. A PT-100 sensor was calibrated using indium, zinc, and lead. To ensure homogeneity and to destroy all crystal nuclei, the samples were heated to 60°C. About 15 mg of the sample was accurately weighed and placed in a standard aluminum crucible and the cover was crimped in place. An empty aluminum crucible with pierced lid was used as a reference. The samples in the pans were stabilized according to IUPAC method (9), which included keeping the samples at 0°C for 90 min, 26°C for 40 h, and 0°C for 90 min prior to introduction into the DSC cell. Thermograms of the samples were recorded by heating at a rate of 2°C/min from −۵ to 50°C. The peak temperatures, heat of fusion (∆H), and the percentage liquid at various temperatures were recorded directly using a TC-11A (Mettler) data processor. SFC was calculated by subtracting percent liquids from 100, and the melting profiles were drawn by plotting percent solids against temperature. DSC was also used to study the solidification characteristics of the samples. About 15 mg of the molten sample was accurately weighed and placed in standard aluminum pans and the covers crimped in place. The samples were introduced into the DSC cell, maintained at 60°C for 5 min to destroy all crystal nuclei, and immediately cooled to −۱۰°C at 5°C/min. The cooling exotherms, crystallization temperatures, and enthalpy of crystallization were recorded. Isothermal solid diagrams. Isothermal solid diagrams were constructed by plotting the SFC at various temperatures (20, 25, 30, 32.5, and 35°C) obtained by DSC against the percentage of the blends. The compatibility or miscibility of mahua fat or its stearin with kokum fat, the blends of mahua/kokum fats, mahua stearin/kokum fat, and Fr. 1 with cocoa butter were determined by constructing isothermal solid diagrams. Fatty acid composition. The fatty acid composition of the samples was determined by analyzing the fatty acid methyl esters by gas chromatography (GC). The methyl esters were prepared using 14% BF3/methanol (10) and were analyzed using a Shimadzu GC-9A (Kyoto, Japan) equipped with a flame-ionization detector operating under the following conditions: column, 2.4 m × ۰٫۳ cm, stainless steel, packed with 15% diethylene glycol succinate coated on Chromosorb W (60/80 mesh); column temperature, 180°C; injector temperature, 200°C; carrier gas, N2, 15 mL/min and hydrogen, 20 mL/min. The peaks were identified by comparing the retention times with those of authentic standards and reported as relative percentage of individual fatty acids. Triacylglycerol composition. The triacylglycerol composition of the samples was determined by high-performance liquid chromatography (HPLC) using a Shimadzu system controller LC-10A and refractive index detector RID-10A. A C18 column (3.9 × ۳۰۰ mm; 5 µm particle size) maintained at 36°C was used. The mobile phase was a mixture of acetone/ acetonitrile (63.5:36.5, vol/vol) at the flow rate of 1 mL/min (11). The samples were purified by passage through a silica gel column and elution of pure triacylglycerols with hexane. The dried samples were dissolved in chloroform and 10 µL was injected. The peaks were identified by comparing the retention times with those of authentic standards and reported as relative percentage of individual triacylglycerols in the sample. Cooling curves. Solidification characteristics of the samples were determined by cooling curves obtained using a Shukoff flask according to the procedure described by Wilton and Wode (12). The cooling curve is of great value in assessing the supercooling quality and solidification behavior of cocoa buttertype fats used in chocolate products. Supercooling property means that the liquid fat, when undisturbed, will remain in the liquid state well below its melting point. The temperature minimum reached on the curve decides the supercooling capacity of the fat; a higher temperature at the minimum point is considered to reduce the fats’ supercooling properties. Fats with reduced supercooling properties will be more sensitive to cold temperatures and will require chilling for an increased time during chocolate making (13).