Ultraviolet Absorbing Efficacy and Photostability of Feruloylated Soybean Oil

Feruloylated soy glycerides (FSG) are a natural‐based, ultraviolet (UV) absorbing, antioxidant vegetable oil synthesized from the lipase‐catalyzed transesterification of ethyl ferulate and soybean oil. Commercial broad spectrum UV absorbing formulations contain multiple UV absorbing compounds that absorb UV radiation in specific regions. The most commonly used compounds are avobenzone (AVO, λ_max 356 nm) and octinoxate (ONX, λ_max 310 nm), which absorb primarily ultraviolet A and ultraviolet B radiation, respectively. The FSG chromophore is chemically similar to ONX but has a λ_max of 328 nm, approximately the median λ_max of AVO and ONX. Equimolar mixtures of AVO–ONX and AVO–FSG, 50 μM:50 μM, solutions in ethanol were compared to determine whether FSG was fungible for ONX in total absorbance capacity, photostability when exposed to UV radiation, and broad spectrum absorbance coverage before and after exposure to UV radiation. While it was determined that AVO–FSG mixtures possessed statistically indistinguishable total absorbance capacity compared to AVO–ONX solutions, AVO–FSG possessed slightly better photostability after 4 hours of UV exposure based on 95% confidence interval comparisons from weighted regression equations. Substituting FSG for half of the ONX (e.g., 50 μM:25 μM:25 μM AVO–ONX–FSG) resulted in the best mixture with total absorbance capacity and photostability statistically equal to the AVO–ONX mixtures but with statistically superior broad spectrum UV absorbance compared to AVO–ONX and AVO–FSG mixtures. The natural, vegetable oil‐based FSG can be substituted on an equimolar bases for ONX in mixtures with AVO to produce formulations with similar to superior efficacy.     

高效液相色谱-蒸发光散射检测器测定脂肪酸和甘油酯的含量

建立了一种利用反相高效液相色谱-蒸发光散射检测、通过梯度洗脱测定油脂中脂肪酸、单甘酯、二甘酯与三甘酯含量的方法,色谱柱是C18反相柱,流动相为乙腈(0.05%醋酸V/V)-二氯甲烷,流速1.0 mL/min;蒸发光散射检测器漂移管温度70℃,载气流速1.7L/min.各物质色谱峰面积的自然对数与浓度的自然对数呈良好的线性关系,精密度RSD为0.43%～2.75%,最低检测限为0.02～0.04μg,回收率测定值为93.2%～104.5%.该方法不仅可以准确、快速地定量、定性分析各类混合脂肪酸甘油酯和游离脂肪酸,而且还可以分离具有立体异构的单甘酯和二甘酯.     

Mechanism of formation of chloropropanols present in protein hydrolysates

Chloropropanols are formed in protein hydrolysates by the reaction of hydrochloric acid with residual lipids associated with the proteinaceous materials used in their production. The products formed from glycerol, triolein, 1,2-diacyl-sn-glycero-3-phosphorylcholine and soya meal have been analyzed by thin-layer and gas chromatography. The yields and isomer ratios of the chloropropandiols and dichloropropanols formed are interpreted in terms of reaction mechanisms for their formation, which involve preferential nucleophilic substitution by the chloride anion at positions activated by neighboring ester groups. These provide anchimeric assistance and govern regioselectivity through steric and electronic effects.     

Chemical composition and physical properties of soft (tub) margarines sold in Malaysia

Seven samples of domestic and imported Malaysian tub margarines were analyzed for their fatty acid and triglyceride (carbon number) composition, solid fat content, dropping and softening points, crystallization temperature, polymorphic form, color, and textural attributes. Domestic margarines were formulated from palm oil or palm olein and palm kernel oil with a liquid oil but no hydrogenated oils. Two imported products contained hydrogenated palm oil product, which resulted in a high level of β′ crystals, whereas the domestic nonhydrogenated products contained more β than β′ crystals. Crystal habit was related to the fatty acid and triglyceride composition of the high-melting glycerides. Domestic products were firmer in texture, probably because they were formulated to be sold in a tropical climate.     

酶法全酯化合成富含EPA/DHA甘油酯工艺研究

以富含EPA/DHA的脂肪酸为底物,采用两步酶法合成富含EPA和DHA的甘油酯。首先,以T1脂肪酶为催化剂催化富含EPA/DHA的脂肪酸和甘油反应;在最优条件为:反应温度40℃,水分添加量为底物混合物的3%、甘油与脂肪酸摩尔比3∶1和酶添加量50 U/g底物混合物时,富含EPA/DHA的脂肪酸的转化率达到62%以上,此时产物中甘油三酯、甘油二酯、甘油单酯的质量分数分别为10.52%、38.15%、25.64%。将游离酶催化酯化反应产物中的油相回收,利用自制的固定化CALB(LipozymeCALB L固定于环氧树脂ECR8285上)为催化剂,在真空条件下继续催化未反应的脂肪酸与偏甘油酯(甘油单酯和甘油二酯)继续酯化反应12 h,此时产物中甘油三酯、甘油二酯和甘油单酯的质量分数分别达到38.34%、51.02%、10.63%,没有检测到脂肪酸的存在。     

Plasmalogens,fatty acids and alkyl glyceryl ethers of marine and freshwater clams and mussels

Shelled molluscs constitute an excellent source of protein, sugars and lipids, and the demand for various mollusks species is increasing. We analysed lipid composition of different bivalves, quite important in the diet of East Mediterranean inhabitants. Plasmamlogens, glyceryl ethers, and diacyl phospholipid forms as well as their fatty aldehydes, fatty alcohols, and fatty acid derivatives were examined. PE of clams and mussels, containing aldehydes C16 (variations from 4% to 31%), C18 (29–46%), C9–18:1(6–32%), C11–20:1 (3–19%), and several minor aldehydes, were detected. The major saturated 1-O-alkyl glycerol ethers C16 and C18. Eicosapentaenoic (EPA) and docosahexaenoic (DHA) acids in both PE and PS plasmalogens were dominated acids. The sum of these acids in PE varied from 33% to 43%, and in PS, from 45% to 66%. EPA levels in PE (30–37%) and PS (39–57%) of marine species were higher than those in freshwater species (PE, 13–16%; PS, 23–29%), and levels of DHA were higher in freshwater than in marine mollusks. A series of saturated fatty aldehydes C12–C24, with major C18:0 in all studied species (over 40%) and C16:0 (10–25%), as well as of unsaturated C16:1 (1–7%) and 18:1 (18–36%) species were isolated from neutral plasmalogens. Predominant fatty acids in neutral plasmalogens were found to be 16:0 (12–17%), 20:5n−3 (9–27%), and 22:6n−6 (9–18%). Distribution of plasmalogens, alkyl glyceryl ethers, and their fatty aldehydes and fatty alcohols in mollusks and other invertebrates is discussed.     

Esterification of fatty acids with glycerol over Fe–Zn double-metal cyanide catalyst

Solid Fe–Zn double-metal cyanide (DMC) complex exhibits high catalytic activity for esterification of fatty acids (FA) with glycerol. DMC catalysts with varying acidities were prepared by synthesizing the material at four different temperatures (10, 25, 50 and 80 °C). The catalyst prepared at 50 °C exhibited highest catalytic activity. Catalytic activity of DMC was influenced by both acidity and surface area. Complete conversion of FA was achieved at 140–200 °C under atmospheric pressure. Chain length of FA was found to influence the rate of reaction and product selectivity.     

抗氧化剂对共轭亚油酸甘油酯氧化稳定性的影响

采用了强化氧化实验条件,以过氧化值为指标,研究了维生素C、维生素E、柠檬酸三钠、甘草抗氧化剂对共轭亚油酸甘油酯氧化稳定性的影响．由过氧化值的一元线性回归方程得出它们对共轭亚油酸甘油酯均有抗氧化作用,甘草抗氧化剂抗氧化效果最好．单独添加质量分数为0．5％VC、0．1％VE、0．05％柠檬酸三钠、0．7％甘草抗氧化剂时,共轭亚油酸甘油酯的氧化稳定性最好．     

Minor constituents of vegetable oils during industrial processing

We report the effects of individual steps of industrial refining, carried out in Brazil, on the alteration of selected minor constituents of oils, such as corn, soybean, and rapeseed oils. Total sterols, determined by capillary gas chromatography (GC), decreased by 18–36% in the fully refined oils, compared with the crude oils. The total steradienes, dehydration products of sterols, were determinedvia a simple clean-up on a short silica gel column, followed by high-performance liquid chromatography (HPLC) with ultraviolet detection. The level of steradienes, normally not present in crude oils, increased after each refining step, especially after deodorization. Thus, the content of steradienes increased after deodorization by about 15- to 20-fold in corn and soybean oils, and by about 2-fold in rapeseed oil. The total steryl esters were also determinedvia clean-up on a short silica gel column, followed by HPLC with evaporative light scattering mass detection. A minor decrease in the level of steryl esters was observed after complete refining. The individual tocopherols and tocotrienols were determined by HPLC with a fluorescence detector. The level of total tocopherols and tocotrienols decreased by about 2-fold after complete refining of corn oil and by about 1.5-fold in soybean and rapeseed oils. In all three cases, maximum reduction of tocopherols was observed after the deodorization step. The level of polymeric glycerides, determinedvia clean-up on a short silica gel column followed by size-exclusion HPLC, increased to some extent (0.4–1%) during refining. The level oftrans fatty acids, determined by capillary GC, also increased to a substantial extent (1–4%) after refining. Part of doctoral thesis of Roseli Ap. Ferrari to be submitted to Faculdade de Engenharia de Alimentos, Universidade de Campinas, Campinas, Brazil.     

分子蒸馏精炼MCT工艺的研究

研究了二级分子蒸馏法精炼MCT的工艺方法.通过进料量、压力、温度的控制得到了纯度为97%的MCT.其最佳的操作条件为:一级分子蒸馏进料量1.6 L/h,温度105～110℃,压力10 Pa;二级分子蒸馏进料量1.2 L/h,温度200～210℃,压力1 Pa.