Lecithin Improves Texture of Reduced Fat Cheeses

Cheddar-type cheeses with 33% fat reduction were made with 0.2 or 0.5% (w/w) lecithin. Reduced fat cheeses with no lecithin and full fat cheeses were prepared as controls. Cheeses were aged 3 mo prior to instrumental and sensory evaluation. Reduced fat cheese with lecithin received higher overall texture scores from dairy judges than reduced fat control cheeses (P ≤ 0.05). Texture scores from dairy judges for cheeses with lecithin were not different from full fat cheeses. Reduced fat cheeses with lecithin were softer than reduced fat control cheeses as measured instrumentally and according to specific attribute panelists (P ≤ 0.05). Cheese wet weight yields were greater with addition of lecithin (P ≤ 0.05) which resulted in a softer more desirable texture in reduced fat cheeses.     

Sensory Evaluation of Reduced Fat Cheeses

The objectives of this research were to compare the effects of seven make-procedures on the sensory quality of reduced fat Monterey Jacktype cheeses. Modifications (decreased cook temperature, decreased ripe time, decreased starter, homogenization, added milk-solids-not-fat, added flavor cultures, and washed curd) were incorporated into standard make-procedures for 33% reduced fat (RF) Monterey Jack-type cheeses. Two controls, a standard full fat cheese, and a standard RF cheese, were also prepared. Cheeses were aged 3 and 7 mo prior to sensory evaluation. The full fat control cheese and the washed curd RF cheese received the highest flavor scores from trained dairy judges (n = 9) and the highest flavor and acceptance scores from a consumer panel (n = 125). Washed curd was an effective modification for optimum sensory quality of RF cheeses.     

乳铁蛋白-乳清分离蛋白乳状液微聚集体构建与酶交联对其流变学特性的影响

以乳清分离蛋白（whey protein isolate,WPI）与乳铁蛋白（lactoferrin,LF）乳状液形成微聚集体与转谷氨酰胺酶酶促交联微聚集体,以期提高体系流变特性。通过微射流分别制备WPI和LF乳状液,二者混合后,乳状液微滴之间发生异型聚集效应,通过转谷氨酰胺酶交联结合形成具有特定三维空间网络结构的微聚集体。研究结果表明：WPI与LF乳状液发生异型聚集,最大程度的聚集和最高物理稳定性体系发生在50% LF-50% WPI微滴形成的微聚集体。异型聚集效应改变了乳状液的流变特性,与单一WPI和LF乳状液相比,50% LF-50% WPI微聚集体流变学特性黏度值分别为单一乳状液的3.72?倍和2.2?倍,通过转谷氨酰胺酶交联,乳状液微聚集体的黏度值为原来的11.4?倍。因此,基于异型聚集效应结合酶促交联,可提高食品体系的流变特性,为开发食品脂质替代物提供了一定的理论支持。     

Thermoirreversible Characteristics of Curdlan Gels in a Model Reduced Fat Pork Sausage

Dynamic viscoelasticity and thermal characteristics of a model reduced fat pork sausage containing curdlan were investigated. Curdlan formed thermoirreversible gels during preparation of sausage at end point temperatures that were within the range in which such gels usually transform from thermoreversible to thermoirreversible. Dynamic viscoelasticity of curdlan gels and thermal characteristics of curdlan aqueous suspensions were analyzed to help explain the physicochemical behavior of curdlan gels in sausage. Once formed curdlan gels exhibited stronger thermoirreversibility with increasing concentrations. The thermoirreversibility could be attributed to the curdlan concentration being higher than the maximum theoretical curdlan to water ratio.     

Pre-Emulsified Corn Oil, Pork Fat, or Added Moisture Affect Quality of Reduced Fat Bologna Quality

Replacing fat with additional water prevented the increase in firmness normally associated with low-fat meat products. Pre-emulsifying the fat or oil also decreased the firmness of reduced-fat bologna. The color of reduced fat bologna was darker for all except the pre-emul-sified corn oil treatments. Redness values for the intact (reduced) fat were the highest of all treatments. Pre-emulsifying fats caused a reduction in redness values for bologna. Flavor and overall acceptability scores from a consumer sensory panel did not differ among bologna samples, but juiciness scores were higher in bologna containing additional water. Accumulated purge in vacuum packages increased with water content in the products and with addition of pre-emulsified oil.     

Effect of Fat Level and Partial Replacement of Pork Backfat with Olive Oil on the Lipid Oxidation and Volatile Compounds of Greek Dry Fermented Sausages

ABSTRACT: High- and reduced-fat Greek fermented sausages were produced with 30% and 20% total fat in the initial formulation. The same products were manufactured with a partial replacement of pork backfat with 20% olive oil. The influence of the modification of the lipid fraction on the oxidation process was evaluated after 2 mo of storage. The reduction of fat increased thiobarbituric acid (TBA) values, total aldehydes, and typical lipid oxidation compounds (hexanal, 2-hexenal, 2-octenal). A significant decrease in oxidation was detected in batches containing olive oil, particularly in the sausages with the highest olive oil content. This addition decreased, in both fat level products, TBA values and hexanal, 2-hexenal, 2,4-hexadienal, benceneacetaldehyde, tt,2,4-nonadienal, and pentadecanal. The addition of olive oil significantly increased monounsaturated fatty acids content.     

喷雾干燥法制取油脂微胶囊技术研究进展

油脂微胶囊现已广泛应用于食品工业,本文简要介绍了油脂微胶囊技术,概述了喷雾干燥法的生产工艺,总结了近年来喷雾干燥技术的发展和创新状况,以期为进一步研究提供参考.     

阿勒泰脂臀羊臀脂分提产物对小鼠肝脏脂质水平及氧化应激的影响

为探讨阿勒泰脂臀羊臀脂及其分提产物对小鼠肝脏脂质水平和氧化应激的影响,将84只昆明小鼠随机分为20 d和40 d两个批次,每批7组（n = 6）:空白组（基础饲料喂养）、菜籽油组、原脂组、2 ℃固脂、12 ℃固脂、22 ℃固脂、32 ℃固脂组,实验油脂组以基础饲料喂养+0.15 mL/10 g的油脂灌服小鼠,测定小鼠肝脏指数,进行肝脏组织病理学观察,按照试剂盒说明书测定肝脏脂质水平及氧化应激指标。结果表明:阿勒泰脂臀羊臀脂及其分提产物对小鼠肝脏指数无显著影响（P>0.05）,肝脏组织无病理性变化;与菜籽油相比,分提产物可有效降低小鼠肝脏脂质水平,其中2 ℃固脂效果更显著（P<0.05）。40 d时,菜籽油组丙二醛（Malondialdehyde,MDA）含量显著高于各组（P<0.05）;32 ℃固脂超氧化物歧化酶（Superoxide dismutase,SOD）、过氧化氢酶（Catalase,CAT）、谷胱甘肽过氧化物酶（Glutathione peroxidase,GSH-Px）活性及总抗氧化能力（Total antioxidation,T-AOC）均显著升高（P<0.05）,而MDA含量显著下降（P<0.05）。随着摄入时间的增长,菜籽油组肝指数显著升高8.21%,原脂组总胆固醇（Total cholesterol,TC）水平显著下降,高密度脂蛋白胆固醇（High density lipoprotein cholesterol,HDL-C）水平显著上升,32 ℃固脂组MDA含量显著降低,SOD活性显著升高30.85%。阿勒泰脂臀羊臀脂的不同分提产物对小鼠肝脏脂质水平、氧化应激产生不同的影响。相比菜籽油,未分提的原脂更有益于人体健康,羊臀脂分提产物中2 ℃固脂可有效控制小鼠肝脏脂质上升,32 ℃固脂提升抗氧化酶活性、减少氧化损伤的效果更优。     

Fabrication of viscous and paste-like materials by controlled heteroaggregation of oppositely charged lipid droplets

This study describes the formation of materials with novel textural characteristics by controlled heteroaggregation of oppositely charged protein-coated lipid droplets. Heteroaggregation was induced by mixing a suspension of β-lactoglobulin (β-Lg)-coated lipid droplets (ζ = −51 mV, d₄₃ ∼ 0.35 μm, 20 wt.%) with a suspension of lactoferrin (LF)-coated lipid droplets (ζ = +32 mV, d₄₃ ∼ 0.35 μm, 20 wt.%) under conditions where the two proteins had opposite charges (pH 7). The mean particle size, flow behaviour, and shear modulus of the materials depended on positive-to-negative particle ratio (0–100%), pH (3–9), ionic strength (0–400 mM), and temperature (30–90 °C). The largest particle sizes, highest viscosities, and largest gel strengths were observed at intermediate particle ratios (40% LF:60% β-Lg), which was attributed to a strong electrostatic attraction between oppositely charged droplets (0 mM NaCl, pH 7, 25 °C). A reduction in particle aggregation, viscosity, and gel strength occurred at intermediate ionic strengths due to screening of the electrostatic attraction between oppositely charged droplets. However, increased aggregation, thickening, and gelation occurred at higher ionic strengths due to screening in electrostatic repulsion between similarly charged droplets. Thermal treatment of the samples (90 °C) promoted a substantial increase in gel strength due to protein denaturation and increased droplet attraction. This study has important implications for the utilisation of controlled particle aggregation to create novel structures in foods, cosmetics, personal care, and other products.     

Influence of Lipid Content in a Corn Oil Preparation on the Bioaccessibility of β‐Carotene: A Comparison of Low‐Fat and High‐Fat Samples

Some individuals with fat maldigestion have compromised digestive systems, which causes the incomplete hydrolyzation of ingested lipids within the gastrointestinal tract (GIT). We studied the influence of high‐fat (20%) and low‐fat (4%) contents on the bioaccessibility of a highly hydrophobic nutraceutical (β‐carotene) through a simulated GIT model consisting of mouth, stomach, and small intestine phases. The low‐fat and high‐fat values were chosen to simulate low‐fat and high‐fat diets. The triglycerides in the low‐fat system were fully digested, whereas those in the high‐fat system were only partially digested, thereby mimicking the digestive systems of individuals who exhibit fat maldigestion. The carotenoids were initially solubilized within oil‐in‐water nanoemulsions prepared using a nonionic surfactant (Tween 20) as emulsifier and a long‐chain triglyceride (corn oil) as the oil phase. After digestion, the total β‐carotene concentration in the filtered micelle phase was much greater for the high‐fat group (0.072 μg/mL) than for the low‐fat group (0.032 μg/mL). Conversely, the β‐carotene bioaccessibility of the high‐fat group (39%) was much lower than that of the low‐fat group (84%), which was attributed to a fraction of the carotenoids remaining in the nondigested lipid phase of the high‐fat group. These results highlight the importance of delivering hydrophobic nutraceuticals in a form where the fat phase is fully digested.     

油脂预乳化液替代脂肪对乳化肠品质的影响

制备鱼油和玉米油预乳化液,研究油脂预乳化液替代猪背膘(质量替代比例分别为25％、50％、75％、100％)对乳化肠主要组分、蒸煮损失、色泽、质构特性、流变特性和感官特性的影响.结果 表明:随着预乳化液替代比例的增加,脂肪含量显著降低(P＜0.05);蒸煮损失也逐渐降低.油脂预乳化液处理组间硬度差异显著并明显高于对照组(...     

不同种类脂肪替代物对软冰淇淋浆料流变特性及产品品质和口感的影响

分别利用浓缩牛乳蛋白（milk protein concentrate,MPC）、菊粉、葡聚糖及其复合物（浓缩牛乳蛋白-菊粉（MPC-inulin,M-I）、浓缩牛乳蛋白-葡聚糖（MPC-dextran,M-D））作为脂肪替代物制作无脂软质冰淇淋。通过仪器分析和感官评价综合分析其替代脂肪效果。结果表明,不同实验组冰淇淋在pH值、滴定酸度和膨胀率方面无明显差异,葡聚糖及菊粉的添加增加了体系稳定性,MPC可以增加体系黏度并延缓融化速率。葡聚糖组冰淇淋具有与对照组冰淇淋相似的粒径分布,而MPC组、菊粉组和M-D组的粒径更小且分布更为集中。M-I组和M-D组的频率扫描和温度扫描的动态流变学参数与对照组更为接近。感官评价分析表明,M-I和M-D组具有较好脂肪类似的口感。回归分析进一步得到整体口感与温度依赖的动态流变学参数的回归模型,为模拟低脂软冰淇淋顺滑细腻的口感提供可行的评价方法。     

猪脂肪诱导氧化过程及添加迷迭香精油的抗氧化活性

分析猪脂肪的氧化过程,绘制猪脂肪在90℃、高氧条件下的诱导氧化过程曲线,并就添加迷迭香精油的抗氧化活性进行分析。结果表明:添加0、0.05、0.10、0.15、0.20、0.25、0.30 g/kg迷迭香精油和添加0.30 g/kg复合抗氧化剂(迷迭香精油0.25 g/kg+VE 0.05 g/kg)的猪脂肪,其氧化反应诱导时间分别为190、228、301、344、393、408、467、497 min,猪脂肪的氧化过程呈现明显的线性关系,在实验条件下,猪脂肪迅速发生氧化反应,迷迭香精油对猪脂肪的氧化作用具有一定的抑制作用,迷迭香精油对猪脂肪的抗氧化作用主要发生在氧化反应的前期,且抑制作用的大小与添加量存在显著的量效关系,同时复合抗氧化剂的作用效果优于单一抗氧化剂,说明不同抗氧化剂之间存在协同增效的作用。     

植物油预乳状液替代猪脂肪对法兰克福香肠品质特性的影响

将1 g/100 mL氧化绿原酸添加到以猪血浆蛋白水解物作为乳化剂所制备的水包油型乳状液中,以此获得高稳定性的植物油预乳状液。然后将该预乳状液以15%、30%、45%和60%的比例替代猪脂肪加入到法兰克福香肠中,探讨替代脂肪比例对香肠品质特性的影响。测定香肠的蒸煮损失、质构、色度以及水分迁移规律,同时测定肉糜的乳化稳定性和流变特性。结果表明,随着预乳状液替代比例的增加,香肠的蒸煮损失显著降低（P＜0.05）,硬度、咀嚼性、L*值和b*值显著增加（P＜0.05）,而弹性、黏结性、感官评价无显著变化（P＞0.05）。低场核磁研究结果发现,预乳状液替代比例的增加能够显著缩短香肠的弛豫时间（P＜0.05）,说明其能增强蛋白质网络对水分子的束缚能力。与此同时,随着预乳状液替代比例的增加,肉糜的乳化稳定性显著增加（P＜0.05）。另外,肉糜的流变学测定结果表明,随着预乳状液替代比例的增加能够显著提高肉糜在加热终点的储能模量（G’）和损失模量（G′′）,而且显著降低了相位角正切值（tanδ）（P＜0.05）。在法兰克福香肠的制作中猪脂肪能够被预乳状液部分替代,而且对香肠的感官无显著影响,尤其以45%的替代量为最佳。     

真空法降低油炸制品含油量

以圆柱形土豆条为研究对象,对油炸和冷却过程中样品表面和内部温度、水蒸气压力以及不同阶段吸油量变化规律进行测量与分析,发现油炸过程中由于水蒸气持续从多孔壳层逸出,阻碍了油进入食品中,土豆样品中70%左右油是在冷却阶段进入食品壳层中的,而且导致吸油的动力--蒸汽冷凝形成的壳层内外压差对环境气压很敏感。在油炸样品冷却阶段,将油炸土豆条置于不同真空环境进行冷却,发现绝对压力80kPa的条件下冷却时,总吸油率从40%降至13.6%,说明冷却过程的真空条件能降低壳层内、外压差驱动力,有效促进表面附着油滴落,阻碍其被吸入食品结构中,从而降低油含量。     

Glutathione affects rheology and water distribution of wheat dough by changing gluten conformation and protein depolymerisation

The effects of reduced glutathione (GSH) on dough rheology, water state and distribution, gluten conformation, and protein molecular weight distribution were investigated. Addition of GSH (0.02−0.04%) resulted in a more viscous and less elastic dough with decreased G′ and increased tanδ values, which suggested decreased cross-links in gluten network and a weakened dough structure. The molecular weight of proteins was reduced by the GSH-induced cleavage of intermolecular disulphide bonds. Fourier transform infrared spectroscopy showed a high fraction of β-sheet formation at the expense of α-helix and β-turns, indicating a destabilised secondary structure and protein depolymerisation. GSH increased water release from the gluten network in dough resulting in an increase in freezable water content and caused water redistributed from bound water to weakly bound water. This study provided insights into correlation between wheat dough rheological properties and gluten structure influenced by GSH.     

木质素调控制备果糖基碳微球及其电化学性能研究

本研究使用果糖作为碳源,木质素磺酸盐协同三嵌段共聚物P123作为模板剂,经过水热碳化法和高温碳化法制备果糖基碳微球材料。探究了木质素磺酸盐对果糖在水热条件下的组装过程及调控机制,并分析果糖基碳微球材料在电化学领域的应用。结果表明,木质素磺酸盐的加入是微球表面形成波纹状突起的决定因素。经高温碳化处理过后得到中空多孔的Yolk-Shell果糖基碳微球材料具有良好的电化学性能,其比表面积为535. 04 m~2/g,孔容为0. 26 cm~3/g;在电流密度为0. 1 A/g时,其比电容为96 F/g,能量密度为3. 16 Wh/kg,功率密度为28. 06 W/kg。     

响应面试验优化两步酶法合成母乳脂替代品工艺及脂肪酸组成分析

采用两步酶法合成母乳脂替代品。以油茶籽油和棕榈酸为原料,在有机相体系中利用脂肪酶Novozym 435催化合成Sn-2位富含棕榈酸的甘油三酯,通过单因素试验和响应面设计,获得了最佳合成条件为反应溶剂正己烷、溶剂用量10 m L/g、底物(棕榈酸-油茶籽油)质量比1.1∶1、脂肪酶用量(以底物质量计)10.1%、反应时间16.5 h、反应温度50℃,Sn-2位棕榈酸含量达到66.08%;以第一步酸解反应得到的甘油三酯和鱼油为底物,经Sn-1,3专一性脂肪酶Lipozyme TL IM催化酯交换制备母乳脂替代品。制品检测结果表明,其不仅棕榈酸的含量和分布与母乳脂相似,而且具有较高含量的二十碳五烯酸、二十二碳六烯酸等多不饱和脂肪酸,亦可作为婴儿配方奶粉的脂肪来源。     

A Comparative Study of the Characteristics of French Fries Produced by Deep Fat Frying and Air Frying

Air frying is being projected as an alternative to deep fat frying for producing snacks such as French fries. In air frying, the raw potato sections are essentially heated in hot air containing fine oil droplets, which dehydrates the potato and attempts to impart the characteristics of traditionally produced French fries, but with a substantially lower level of fat absorbed in the product. The aim of this research is to compare: (1) the process dynamics of air frying with conventional deep fat frying under otherwise similar operating conditions, and (2) the products formed by the 2 processes in terms of color, texture, microstructure, calorimetric properties, and sensory characteristics. Although, air frying produced products with a substantially lower fat content but with similar moisture contents and color characteristics, it required much longer processing times, typically 21 min in relation to 9 min in the case of deep fat frying. The slower evolution of temperature also resulted in lower rates of moisture loss and color development reactions. Differential scanning calorimetry (DSC) studies revealed that the extent of starch gelatinization was also lower in the case of air fried product. In addition, the 2 types of frying also resulted in products having significantly different texture and sensory characteristics.