不同条件下乌桕类可可脂结晶行为之研究

液化后的CTCBE如果在室温下自然缓慢冷却凝固则导致容器以横向力炸裂，而以冷冻方式使之快速冷却固化，则容器完好无损，CB则不会出现类似情况。为了解这一现象与CTCBE结晶行为的关系，拟用X粉末衍射和差示扫描量热法对乌桕类可可脂和天然可可脂在不同条件下的结晶行为进行了研究。结果表明过 冷度和诱导晶核对乌桕类可可脂和天然可可脂的结晶行为有不同的影响。对乌桕类可可脂而言，过冷度对有诱导晶核存在的结晶行为无明显影响，相反对无诱导晶核的结晶行为则有较大影响。天然可可脂则不然，过冷度的变化对有或没有诱导晶核存在的结晶行为均有很大影响；如果过冷度相同，则有或没有诱导晶核存在的结晶行为无太大差异。     

月桂酸类代可可脂巧克力脂霜组成及形态学研究

通过气相色谱分析和显微镜观察对起霜前后月桂酸类代可可脂巧克力的脂肪酸组成以及形态学特征进行了研究。结果表明,与新鲜巧克力相比,脂霜中C12∶0、C18∶0、C18∶1含量明显增加,而C14∶0含量相对减少;原子力显微镜结果显示,新鲜巧克力表面相对平滑,起霜后平滑表面破坏,形成明显凹凸面;扫描电镜观察发现新鲜巧克力表面结晶网络结构疏松,起霜巧克力表面油脂晶体形成致密网络结构;偏光显微镜显示脂霜中晶体颗粒明显大于新鲜巧克力晶体颗粒,发生了向更稳定晶体的转变。     

牛油与菜籽油、氢化菜籽油混合应用于起酥油的研究

在两种氢化条件下:温度160℃、H2压力2.5×105Pa,温度200℃、H2压力1.0×105Pa,首先对菜籽油进行氢化。后将牛油与菜籽油、氢化菜籽油以各个比例混合,通过脉冲式核磁共振仪对物系的固体脂肪含量(SFC)进行测量,利用实测SFC与理想SFC之间的偏差曲线来研究二元物系的相容性情况。得到牛油与160℃氢化60min菜籽油以1∶1比例混合时,相容性较好,20℃条件下结晶细腻,满足起酥油的SFC分布和塑性要求。     

Effect of the Addition of a Cocoa Butter–Like Fat Enzymatically Produced from Olive Pomace Oil on the Oxidative Stability of Cocoa Butter

ABSTRACT:  A cocoa butter (CB)–like fat was produced in a packed bed enzyme reactor using sn -1,3 specific lipase, and its blends with CB were prepared at different ratios (CB: CB-like fat; 100: 0, 90: 10, 80: 20, 70: 30, 60: 40, 50: 50, 0: 100). The oxidation kinetics of CB: CB-like fat blends was studied by differential scanning calorimeter (DSC). Samples were heated in DSC at different temperatures (130, 140, 150, 160 °C) under 100 mL/min oxygen. From DSC exotherms, oxidation induction times (OIT) were determined and used for the assessment of the oxidative stabilities of the blends. Oxidation kinetics parameters (activation energy, E_a ; preexponential factor, Z ; and oxidation rate constant, k ) were calculated. In general, it has been observed that above 110 °C increasing the ratio of CB-like fat in the blend increased the k value with increasing temperature. It has been observed that for all blends the increase in k value with temperature was significant ( P < 0.05). Increasing CB-like fat ratio in the blend decreased the content of major TAGs (1,3-dipalmitoyl-2-oleoyl-glycerol [POP]; 1[3]-palmitoyl-3[1]stearoyl-2-oleoyl-glycerol [POS]; 1,3-distearoyl-2-oleoyl-glycerol [SOS]), and decreased the oxidative stability of the blends.     

改善牛肉脂肪品质替代品的研究

以植物油为溶剂,水为溶质,添加卵磷酯、单硬脂酸甘油酯、山梨醇酐单油酸酯(Span80)、乳清蛋白等其他添加成分,研制肥牛脂肪替代品,采用了4因子二次通用旋转组合设计,得出最佳配比为单硬脂酸甘油酯0.434%,山梨糖醇酐脂肪酸酯0.110%,卵磷酯0.504%,乳清蛋白0.410%。用冲淡法检测乳状液类型为W/O型。乳状液稳定性的检测结果,测其体积比率为0.59%,达到了稳定体系的要求。     

Transaminase (AST/GOT and ALT/GPT) Activity in Ground Beef as a Means of Determining End-point Temperature

Thermal processing conditions [rate of temperature increase, 0.35°C or 3.5°C/min; end-point temperature (EPT), 57.2, 71.1, and 79.4°C; dwell time, 0 and 30 min; and enzyme extraction medium (deionized water, 0.9% saline, and pH 7 buffer)] affected glutamic oxalacetic transaminase (GOT; aspartate aminotransferase, E.C. 2.6.1.1) and glutamic pyruvic transaminase (GPT; alanine aminotransferase; E.C. 2.6.1.2) activity in thermal treated ground beef samples. There was greater loss of GOT activity in samples heat processed at 0.35°C/min than samples heat processed at 3.5°C/min with depletion nearly to zero between 71.1 and 79.4°C. More GOT activity was noted when samples were extracted with 0.9% saline solution. GPT activity was low in all samples and was present after heating to 79.4°C.