Increasing Conjugated Linoleic Acid Content in Milk and Cheese after Supplementing a Blend of Crude Soybean Oil Sediment Combined with Fish Oil to Grazing Dairy Cows

The aim of the work was to improve the healthy value of milk and cheese fatty acids (FA) by feeding a mix of crude soybean oil sediment (CSOS) combined with fish oil (FO) to grazing dairy cows. The CSOS is a by-product commonly discarded after oil extraction containing 3.3% moisture, 6% total ash and 70.7% oil, locally available, comparatively economic and easy to mix with other feed ingredients. The experiment lasted 55 days from September 30th to November 23th 2018 and was carried out at the dairy farm “Gacef” provider of milk to the dairy industrial plant “Capilla Del Señor” (CDS) located at the Villa María City, Córdoba Province, Argentine. A herd of 80 multiparous Holstein cows producing 24 kg-1 milk·cow-1·day-1 was used. The cows grazed an alfalfa and an oat pasture that represented about 47% of total dry matter (DM) intake supplemented at 8.5 kg DM·cow-1·day-1 with a total mixed ration (TMR) composed (DM basis) by cracked corn grain (35.18%), whole plant corn silage (31.98%), pelletized soyben meal (17.99%), the CSOS supplement (13.85%) and FO (0.99%). The TMR was supplied by halves after each milking time in groupal feeders yielding 1.4 kg·cow-1·day-1 of the CSOS and 0.1 kg·cow-1·day-1 of FO. Before the start of lipid supplementation, milk samples (5) were obtained from the farm-tank representing the standar or reference milk (Ref-Milk). After 21 days of supplementary lipid supply, additional milk samples (5) were obtained representing the modified milk (Mod-Milk). Milk samples were analyzed for chemical composition and milk FA profile. At each time, sufficient quantities of both (Ref- and Mod-Milk) were collected for manufacturing six types of cheeses. The results were analyzed through the Student-T test for independent observations. Oil supplementation did not modify (P > 0.05) the chemical composition of milk. Concentration of butyric acid (C4:0) in milk was not affected (P < 0.858). Concentration of total saturated FA (SFAs) in Ref-Milk averaged 58.83 g 100 g-1 FA and was decreased to 49.67 g 100 g-1 FA in Mod-Milk (P < 0.0001). Monounsaturated FA (MUFAs) increased (P < 0.001) from 32.03 g 100 g-1 FA in Ref-Milk to 38.13 g 100 g-1 FA in Mod-Milk (+19.07%) whereas polyunsaturated FA (PUFAs) increased (+36.1%) from 4.71 to 6.41 (P < 0.004). The Mod-Milk showed a significant (P < 0.002) reduction (-15.3% or 5.9 g 100 g-1 FA) for the total concentration of the potentially atherogenic fraction of milk FA (C12:0 to C16:0). The atherogenic index (AI) also decreased (P < 0.012) from 1.98 in Ref-Milk to 1.42 in Mod-Milk (-28.4%). Concentration of vaccenic acid (VA, trans-11 C18:1) in Mod-Milk averaged 7.77 g 100 g-1 FA which represented a 162 % increase (P < 0.0001) over that observed in Ref-Milk (2.95 g 100 g-1). Concentration of conjugated linoleic acid (CLA, cis-9, trans-11 C18:2) in Ref-Milk averaged 1.47 g 100 g-1 FA and showed an important increase (P < 0.002) in the Mod-Milk (3.86 g 100 g-1 FA, +163%). The omega 6/3 ratio resulted lower (P < 0.012) in the Ref-Milk (2.28) compared to the Mod-Milk (2.83). Milk and cheese FA composition were highly correlated (R2 = 0.99, P < 0.0001). The Mod-Cheeses showed similar results in AI, total concentration of SFAs, MUFAs and PUFAs compared to the milk of origin. Differences in FA composition between the cheeses made with the Ref- and Mod-Milk were equivalent to those described for milks. It is concluded that supplementation with a blend of CSOS supplement and FO was an effective way to improve the healthy value of dairy products by reducing contents of SFAs, atherogenic FAs and the atherogenicity index with a concomitant increase in VA and CLA. Modifications induced in the Mod-Milk were recovered in the Mod-Cheeses. The results obtained may help to reduce saturated fat intake and fight or prevent incidence of non-communicable, cardiovascular and chronic diseases.

大豆油脚浸出油制备生物柴油及性能研究

大豆油脚浸出油与甲醇在催化剂KOH作用下通过酯交换反应制得生物柴油(BDF)。用气相色谱法跟踪研究醇油摩尔比、反应温度、反应时间及催化剂用量对产物生物柴油浓度的影响,正交实验得到大豆油脚浸出油制备生物柴油最佳工艺条件为:反应温度45℃、催化剂用量1%、醇油摩尔比6∶1、反应时间45 min,生物柴油含量为96.8%。生物柴油的主要性能指标符合0#柴油标准(GB 252-1994)。考察了大豆油脚浸出油酯交换反应的动力学,由实验数据绘制的动力学曲线呈现出酯交换反应在开始阶段为二级反应,并逐步转变为一级反应,反应后期为零级反应。由动力学实验数据求出酯交换反应的动力学参数,酯交换反应的活化能为47.71 kJ/mol,频率因子为6.01×107L/(mol.min)。

分子蒸馏法从大豆油脚中提取辅酶Q_(10)的研究

采用分子蒸馏法从大豆油脚中提取辅酶Q10,提取分离辅酶Q10最佳工艺条件为:真空度0.01Pa,蒸馏温度190℃,刮板转速600 r/min,物料流量1.0 mL/min。最佳条件下轻相得率为85.12%,轻相中辅酶Q10含量为1.85 mg/g。轻相经纯化后辅酶Q10结晶纯度为92.5%。研究证明此方法提取大豆油脚中的辅酶Q10是可行的。

分离和鉴定大豆油脚中甾醇及副产物成分

从大豆油脚中提取的粗甾醇,经丙酮洗涤,乙醇反复萃取,抽滤烘干得精制甾醇,再通过结晶,干燥得结晶甾醇。在乙醇萃取过程中分离出大豆甾醇和两种副产物———醇热溶絮状析出物和醇不溶物。经等离子发射光谱和气质联机分析表明,结晶甾醇中大豆总甾醇含量为94%,其中β-谷甾醇44.1%、豆甾醇28.0%、菜籽甾醇21.7%;精制甾醇中大豆总甾醇含量为85%,其中β-谷甾醇42.3%、豆甾醇18.1%、菜籽甾醇24.5%。醇热溶絮状析出物分离出15种化合物,多数为脂类化合物。醇不溶物中矿物质约占30%,Al、Fe、Ca、Mg、P、Mn、Zn、Sr、Ti等含量较高。

超声波对大豆水化油脚-磷脂酶A_2反应体系的影响

大豆磷脂酶改性可以明显改善其O/W乳化性能,磷脂酶改性反应时间一般需要7h,而超声波处理则可明显缩短反应时间。以大豆水化油脚为原料,研究了超声波处理对磷脂酶A2制备酶改性大豆磷脂的影响。结果表明,在pH7.5,55℃反应条件下,采用超声波辅助反应40min后,所制备的溶血磷脂HLB值达到8,与未采用超声波溶血磷脂HLB值相同。超声波促进磷脂酶改性效果明显。

大豆油脚生产脂肪酸的工艺研究及经济效益评价

通过对大豆油脚生产脂肪酸的试验 ,研究了大豆油脚常压条件下水解的主要工艺条件和影响因素 ,为油脚水解脂肪酸工业生产中最佳工艺条件的选定提供了依据 。

柱色谱法制备大豆脑磷脂和肌醇磷脂

采用溶剂萃取法和柱色谱法相结合的工艺,从大豆油脚中制备肌醇磷脂,研究了不同洗脱剂对柱色谱分离脑磷脂和肌醇磷脂效果的影响。结果表明,大豆油脚先经脱水、脱油,再经95%乙醇浸提后粗分为粗卵磷脂和粗脑磷脂。以硅胶为吸附介质,以粗脑磷脂为原料用V(氯仿)∶V(甲醇)=2∶1的混合溶剂等度洗脱,可获得纯度为80.1%的大豆脑磷脂和90.6%的肌醇磷脂产品。

大豆水化油脚生物柴油的研制

介绍了从大豆水化油脚中提取制备生物柴油原料的方法和相应的生物柴油制备方法。其主要过程是对油脚进行酸化脱水,选用有机溶剂充分萃取其中的油脂,再用减压装置回收溶剂,油脂则作为酸催化酯交换法制备生物柴油的原料。结果表明,油脂的萃取率达95%以上,萃取剂的回收率达98%;酸法酯交换法制备生物柴油的反应条件为:反应时间4h,反应温度65℃,催化剂的加入量1.5%,醇油的摩尔比约6∶1。

大豆油脚提取磷脂及卵磷脂的工艺研究

考察了从大豆油脚中提取磷脂和卵磷脂的最佳工艺条件。采用正交实验的方法、产品性状分析和磷脂产品含量测定三个方面综合考虑,确定粉末磷脂的最佳提取工艺为脂溶比1∶3,浸提温度45℃左右,浸提时间30 min,浸提3次。通过单因素实验,从粉末磷脂中提取卵磷脂。对卵磷脂的性质、乙醇回收率进行了考察。最佳提取条件为:提取温度60℃,脂溶比1∶3,提取2次。本工艺流程简单、成本低廉,溶剂回收率高,磷脂和卵磷脂含量较高,具有一定的现实意义。

大豆油脚中大豆磷脂的提取

通过离心提取新鲜大豆油脚的中层分离物,将其与丙酮充分混合,经减压抽滤、真空干燥得到大豆磷脂并对该过程提取条件进行了优化.结果表明,最佳提取条件为离心转数5 000 r/min,磷脂与丙酮的体积比为1∶6,丙酮洗涤3次,得到相对质量分数为86.78%的大豆磷脂.

大豆油脚中混合脂肪酸提取工艺的研究

以大豆油脚为原料,盐酸水解后用索式提取器和真空旋转蒸发仪提取,研究大豆油脚中混合脂肪酸的提取工艺。通过正交实验确定索氏提取的最佳工艺条件是:加热时间为45 min,加热温度为75℃,盐酸浓度为22%;采用真空旋转蒸发的最佳工艺条件为:加热时间为45 min,加热温度为75℃,真空度为91.9 kPa。在两种最佳工艺条件下,采用真空旋转蒸发仪提取的脂肪酸含量(98.8%)比采用索式提取器提取的脂肪酸含量(90.18%)高。两种工艺中,真空度、盐酸浓度对提取的脂肪酸含量有一定影响,而加热时间和加热温度对脂肪酸含量影响不大。