辛烯基琥珀酸淀粉酯对人造奶油品质的影响

研究了辛烯基琥珀酸淀粉酯作为脂肪替代品对奶油品质的影响,研究不同添加量对人造奶油的搅打起泡率、脂肪部分聚结率、触变性、质构特性、晶体特性的影响。结果表明:随着辛烯基琥珀酸淀粉酯添加比例的增大,人造奶油的感官品质、搅打起泡率、脂肪部分聚结率和质构强度逐渐下降,其触变环逐渐变大,当添加量超过12%时各项指标变化趋于明显。综合考虑人造奶油的感官品质、搅打性能、晶体结构的稳定性及触变环面积与质构特性的适宜范围等因素,辛烯基琥珀酸淀粉酯在人造奶油中的最适脂肪替代率为12%。      

Preparation and properties of zeroTrans soybean oil margarines

Experimental margarines were prepared in the pilot plant from interesterified soybean oil-soybean trisaturate blends and compared to a product made from hydrogenated soybean oil. Penetration, yield values, and water/oil off-data were determined. Margarine prepared from an interesterified soy-soy trisaturate blend (80:20) tended to crystallize slowly after votation and resulted in a somewhat harder than desirable product. However, addition of 20% liquid soybean oil to the interesterified oil yielded a softer product. The experimental products showed excellent oil and water loss properties under accelerated storage conditions.     

Storage of commercial margarine at different temperatures

The effect of storage temperature on the consistency of commercial margarine was analyzed by viscometry, differential scanning calorimetry (DSC), microscopy at low temperature and X-ray diffraction. The results obtained show that samples harden at 13°C and soften at 4°C. The greater strength of samples was apparently associated with crystals of higher melting points. Recrystallization takes place during storage leading to more stable solid solutions with higher melting points.     

Development of an analytical method for the simultaneous analysis of MCPD esters and glycidyl esters in oil-based foodstuffs

Substantial progress has been recently made in the development and optimisation of analytical methods for the quantification of 2-MCPD, 3-MCPD and glycidyl esters in oils and fats, and there are a few methods currently available that allow a reliable quantification of these contaminants in bulk oils and fats. On the other hand, no standard method for the analysis of foodstuffs has yet been established. The aim of this study was the development and validation of a new method for the simultaneous quantification of 2-MCPD, 3-MCPD and glycidyl esters in oil-based food products. The developed protocol includes a first step of liquid–liquid extraction and purification of the lipophilic substances of the sample, followed by the application of a previously developed procedure based on acid transesterification, for the indirect quantification of these contaminants in oils and fats. The method validation was carried out on food products (fat-based spreads, creams, margarine, mayonnaise) manufactured in-house, in order to control the manufacturing process and account for any food matrix–analyte interactions (the sample spiking was carried out on the single components used for the formulations rather than the final products). The method showed good accuracy (the recoveries ranged from 97% to 106% for bound 3-MCPD and 2-MCPD and from 88% to 115% for bound glycidol) and sensitivity (the LOD was 0.04 and 0.05 mg kg^?1 for bound MCPD and glycidol, respectively). Repeatability and reproducibility were satisfactory (RSD below 2% and 5%, respectively) for all analytes. The levels of salts and surface-active compounds in the formulation were found to have no impact on the accuracy and the other parameters of the method.     

基料油相容性及乳化剂对人造奶油结晶行为的影响

利用低场脉冲核磁共振仪和偏振光显微镜、粉末X-射线衍射等分析手段分别对棕榈油基混合体系的相容性以及乳化剂种类对以此为基料油制备的人造奶油结晶行为的影响进行了研究。结果表明:经混料回归设计的1号(POs∶PMF∶PKO,0.8∶0.1∶0.1)、4号(POs∶PMF∶PKO,0.45∶0.45∶0.1)配方相容性最好,6号(POs∶PMF∶PKO,0.1∶0.45∶0.45)配方出现严重共晶现象,且在20℃左右共晶最为严重;向1号配方添加丙二醇酯及向4号配方添加聚甘油酯所得产品b和c均为β’晶型;产品c的晶体形态最易受温度波动的影响。     

核磁共振代谢组学技术鉴别天然奶油与人造奶油

采用核磁共振(nuclear magnetic resonance,NMR)代谢组学技术对天然奶油和人造奶油的氘代氯仿(CDCl_3)提取物进行了鉴别研究。结果表明:与麦淇淋相比,黄油中甾醇、丁酸、1-戊烯、共轭亚油酸含量较高,而总不饱和脂肪酸、亚油酸的含量较低;与植脂奶油相比,稀奶油中甾醇、丁酸、亚麻酸、亚油酸、1-戊烯、共轭亚油酸、总不饱和脂肪酸含量较高,而总饱和脂肪酸含量较低,并且都具有显著性差异(P0.05)。其中脂肪酸的代谢组学分析结果与气相色谱法所得结果一致。建立的基于NMR代谢组学技术对天然奶油与人造奶油快速、简便的鉴别方法,可以鉴定不同种类奶油的差异化学成分,为奶油制品的品质鉴别和质量控制研究提供分析方法。     

Physiochemical and oxidative stability of interesterified structured lipid for soft margarine fat containing Δ5-UPIFAs

Structured lipid (SL) was synthesized from pine nut oil (PNO) and palm stearin (PS). In SL, 8.81% of Δ5-unsaturated polymethylene interrupted fatty acids (Δ5-UPIFAs) were intentionally incorporated into the sn-2 position through acyl migration. The obtained SL contained mostly the β′ form and a wide plastic range with solid fat index of 26.5% at 10 °C to 2.29% at 35 °C, indicating that the obtained SL (containing zero-trans fatty acid) may be desirable for soft (tub) margarine fat. Subsequently, the antioxidative effects of α-tocopherol (α-TOH), ascorbyl palmitate (AP), quercetin (Qu), and combinations thereof on SL were investigated. Results showed that Qu (500 μg/g) showed the most effective antioxidant activity, followed by AP (500 μg/g); while α-TOH with any concentrations (100, 200 and 500 μg/g) did not show significant protective activity in the obtained SL. Each mixture of AP + Qu and α-TOH + AP + Qu also showed effective antioxidant activity in the obtained SL.     

Monitoring hydrogenation in the margarine industry by low resolution pulsed NMR

An N M R method has been developed to monitor the hydrogenation of various oils used as raw materials in the margarine industry. The method is based on the determination of a monoexponential approximation of the longitudinal relaxation time, T1, which is shown to be highly correlated with the iodine number.     

Storage stability of margarines produced from enzymatically interesterified fats compared to those prepared by conventional methods – Chemical properties

In this study, four margarine hardstocks were produced, two from enzymatically interesterified fats at 80 and 100% conversion, one from chemically randomized fat and one from physically mixed fat. These four hardstocks, blended with 50% sunflower oil, were mainly used for the production of table margarines in a pilot plant. Storage stability studies were carried out at storage temperatures of 5 and 25 °C for 12 wk. Margarines from the enzymatically interesterified fats were compared to the margarines produced by the conventional methods (chemical interesterification and physical blending) and to selected commercial margarines. The changes in the chemical properties of the products, including peroxide values (PV), tocopherols, free fatty acids, volatile oxidation products, and sensory evaluation, were examined during storage. It was observed that the margarine produced from the chemically interesterified fat had higher PV in weeks 4, 8 and 10 than the margarines produced from the enzymatically interesterified fats and the physically blended fat. These differences were not caused by different contents of tocopherols in the hardstocks. The differences between the processes for chemical and enzymatic interesterification, including further treatment stages, might be responsible for the development of a high PV in the margarine produced from the chemically interesterified fat. However, the contents of volatiles did not show the same tendency as observed for PV for the margarines stored at 25 °C during 12 wk. Storage at 25 °C accelerated oxidation compared to storage at 5 °C. The content of δ‐ and γ‐tocopherols decreased faster than the content of α‐ and β‐tocopherols during storage. This phenomenon was only affected by storage time, not by storage temperature. Sensory analysis did not show consistent differences between the produced margarines and commercial margarines, and no hydrolysis occurred for these four margarines during storage. The margarines produced from the enzymatically interesterified fats had low PV and a similar taste and smell compared to the margarine produced from the chemically interesterified fat.     

Potential margarine oils from genetically modified soybeans

Genetically modified soybeans were processed into finished, refined, bleached, and deodorized oils. Fatty acid composition was determined by gas-liquid chromatography. Glyceride structure was characterized according to degree of unsaturation by high-performance liquid chromatography, lipase hydrolysis, and gas-liquid chromatography. Compared to common varieties with 15% saturated acids, genetically modified soybeans yielded oils containing 24–40% saturated acids. Several varieties were examined, including the Pioneer A-90, Hartz HS-1, and Iowa State A-6 lines. Pioneer A-90 contained 17% stearic acid, had a solid fat index (SFI) of 6.0 at 10°C (50°F) and zero from 21.1 to 40°C (70 to 104°F), and therefore lacked sufficient solids for tub-type margarine. To improve its plastic range, the Pioneer oil was blended with palm oil, randomized palm oil, or interesterified palm/soy trisaturate basestock. After blending with 10–40% of these components, the high-stearic acid oil had an SFI profile suitable for soft tube margarine. The A-6 varieties, 32–38% saturates, showed SFI profiles with sufficient solids at 10°C (50°F) and 21.1°C (70°F) to qualify as a stick-type margarine oil, but lacked sufficient solids at 33.3°C (92°F); however, after small amounts (2–3%) of cottonseed or soybean hardstocks were added, the A-6 oils qualified as stick margarine oil. The HS-1 variety, when blended with small amounts (2–3%) of hardstock, possessed sufficient solids at 10°–33.3°C (50–92°F) to prepare soft tub margarine oil. Presented at the AOCS Annual Meeting & Expo, San Antonio, Texas, May 8–12, 1995.