Dissertation > Industrial Technology > Light industry,handicrafts > Food Industry > Beverage cold manufacturing industry > Cocoa, chocolate,malted milk

Biosythesis of Cocoa Butter Improvers

Author WangLingYan
Tutor WangXingGuo
School Jiangnan University
Course Cereals, Oils and Vegetable Protein Engineering
Keywords Cocoa butter improver 1, 3-regiospecific lipase enzymatic acidolysis molecular distillation fractionation
Type Master's thesis
Year 2011
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Cocoa butter improver (CBI) is defined to be harder version of cocoa butter equivalent (CBE) due to the high content of 1, 3-distearoyl-2-oleoylglycerol (SOS). To date, CBI has been used to improve hardness of some softer qualities of cocoa butter or to improve fat bloom resistance or higher temperature resistance of chocolate products. The preparation, purification and physiochemical properties of CBI were studied in the present study.Product rich in SOS was produced vice acidolysis reactions of stearic acid and high oleate sunflower seed oil by Lipozyme RM IM in free solvent. The impact factors of water content, enzyme load, ratio of stearic acid to high oleate sunflower seed oil, reaction time, reaction temperature on SOS, SSO and SSS content were investigated. High content of SOS was expected, as well as the low contents of SSO and SSS. The results showed that the optimum conditions were water content 1%, enzyme load 10% of substrate, ratio of stearic acid to high oleate sunflower seed oil 4.46:1, reaction time 2h, and reaction temperature 70℃. Under these conditions, the content of SOS, SSO and SSS in reaction products was 41.05%, 0.63%, respectively.Product rich in SOS was purified by molecular distillation, and the optimum conditions were obtained: distillation temperature 220℃, scraper rotation rate 100r/min, feed materiel quantity 2mL/min, preheating temperature 80℃and vaccum pressure 3Pa.By the first and second-class, acid value of heavy phase was reduce to 0.26mgKOH/g. Removal of DAG extraction by solvent extraction was studied, and the optimum conditions were obtained: extraction temperature 60℃, when solid-liquid radio 1:4, re-extraction 1 time and when solid-liquid radio 1:2, re-extraction 2 times, the content of DAG was removed to 1.33% and the recovery rate of triacylglycerols was 89.83%.In the process of solvent fractionation, the optimum conditions were: crystallization temperature 13.79℃, crystal growth time 4.63h, liquid-solid ratio 4.47:1, the purity and recovery rate of SOS in stearin was 87.92% and 99.72%, respectively. What is more, the physiochemical properties of CBI were obtained: content of SOS 87.16%, color Y15R2.0, AV 0.07mgKOH/g, PV 0.35mmol/kg, p-AV 1.17, IV 33.6gI/100g, SV 199.0mgKOH/g. It showed similar triacylglycerols composition and DSC melting thermograms and cooling thermograms. As well, the content of SOS, SFC and the slope of the isothermal crystallization curves were slight higher than the foreign CBI. So, it proved that self-made CBI is similar to the foreign CBI in the physiochemical properties.

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