Changes in lipids and their contribution to the taste of migaki-nishin (dried herring fillet) during drying

This study was conducted to investigate the changes in lipids and their effect on the taste of migaki-nishin during drying. Lipid was extracted from herring fillets following different drying stages to measure the degree of lipid oxidation and changes in lipid composition, and fatty acid profile. Peroxide value, carbonyl value and acid value of the lipids were significantly increased (P < 0.05) during the drying period. Marked increase in free fatty acids, with decreases in triglyceride and phospholipid content were observed in proportion to drying time and this result suggested that hydrolysis was induced by lipases and phospholipases. The decreases in polyunsaturated fatty acids (PUFAs), especially eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), were observed in the total lipids and phospholipid fraction. In addition, significant increase in PUFAs especially DHA was found in the free fatty acid fraction. Sensory evaluation showed that an addition of DHA to mentsuyu significantly (P < 0.05) enhances the intensities of thickness, mouthfulness and continuity. These results suggest that during drying period lipid oxidation was not only occurred but also lipolysis predominantly released DHA, which might have a contribution to kokumi enhancement of migaki-nishin.     

变温调控破囊壶菌发酵生产二十二碳六烯酸

破囊壶菌Aurantiochytrium sp.细胞生长、油脂积累及二十二碳六烯酸(docosahexaenoic acid,DHA)合成与培养温度密切相关.该研究在摇瓶中考察了不同温度对破囊壶菌发酵的影响,结果表明,20～35℃的培养温度较利于破囊壶菌细胞的生长,而25～28℃的培养温度利于油脂的积累;虽然15℃培养...     

吐温对钝齿棒杆菌产L-精氨酸代谢的影响

目的:以课题组构建的钝齿棒杆菌(Corynebacterium crenatum)MT NAGK M4 △proBANcgl1221AdtsR1(CCM01)为出发菌株,探究吐温(Tween)对该菌产精氨酸代谢的影响.方法:优化精氨酸发酵及Tween质量浓度,测定菌体生长量、L-精氨酸产量、发酵液残糖量考察Tween ...     

基于脂质组学揭示饲喂裂殖藻粉对山羊乳脂质的影响

基于气相色谱法和超高效液相色谱-四极杆-飞行时间串联质谱法探究饲喂裂殖藻粉（Schizochytrium spp.）对山羊乳脂肪酸组成及全脂质组成的影响，并与市售纯牛乳和二十二碳六烯酸（docosahexaenoic acid,DHA）牛乳进行差异性分析。结果表明，山羊乳脂肪含量显著高于牛乳，肉豆蔻酸、棕榈酸和油酸是乳中主要的脂肪酸组成。饲喂裂殖藻粉能显著增加山羊乳中DHA含量。甘油三酯是2种乳中主要的脂质成分，山羊乳中磷脂含量显著高于牛乳。DHA在乳品脂质中主要以甘油酯型DHA形式存在，山羊乳较牛乳含更丰富的磷脂型DHA。裂殖藻粉添加量50 g/d为山羊乳中DHA富集的最佳添加量。通过在日粮中添加DHA原料，能够进一步提高山羊乳的营养价值，解决目前膳食DHA来源单一的问题。本研究为婴幼儿配方奶粉及富DHA功能性乳脂产品的开发和营养调控提供有力的理论依据和参考，并为乳制品类型的鉴定提供方法与数据基础。     

MICROALGAE AS A SOURCE OF FATTY ACIDS

Microalgae are a very diverse group of organisms that consist of both prokaryotic and eukaryotic forms. Although most microalgae are phototrophic, some species are also capable of heterotrophic growth. Some species of microalgae can be induced to overproduce particular fatty acids through simple manipulations of the physical and chemical properties of the culture medium. As a result of the profound differences in cellular organization and growth modes and the ability to manipulate their fatty acid content, microalgae represent a significant source of unusual and valuable lipids and fatty acids.
The utilization of microalgal lipids and fatty acids as food components requires that these organisms be grown at large scale under controlled conditions. Several growth systems have been developed for large scale growth of phototrophic microalgae using either natural sunlight or artificial light, but their lack of control of culturing parameters or their high cost of operation have limited their utility for the production of food products. Instead, large scale cultivation of heterotrophic microalgae using classical fermentation systems provides consistent biomass produced under highly controlled conditions at low cost.
Microalgae contain many of the major lipid classes and fatty acids found in other organisms. However, they are also the principal producers in the biosphere of some polyunsaturated fatty acids, especially docosahexaenoic acid (DHA). The high DHA content found in some algae is currently being utilized to supplement infant formula to enable it to more closely resemble human breast milk. Thus, the commercialization of DHA from microalgae demonstrates the value of these organisms as a source of useful fatty acids.     

Impact of salt and lipid type on in vitro digestion of emulsified lipids

This study examined the effects of oil type and NaCl addition on the micro-structural changes that occur to emulsified lipids as they pass through a model gastrointestinal tract (GIT). Oil-in-water emulsions stabilized by a non-ionic surfactant (Tween 20) were prepared using different kinds of lipids (3% soybean oil, corn oil, olive oil or lard). The emulsified lipids were passed through an in vitro digestion model that simulated the composition (pH, minerals, surface active components, and enzymes) of the human GIT. Prior to digestion, emulsified lipid droplets appear to be bridging flocculation in 1% NaCl added emulsified lipids, moreover lipid droplets of 1% NaCl added emulsified lipids seems to be more disrupted than no NaCl added emulsified lipids. Mean particle size prepared with lard was smaller than those of other emulsified lipids. Free fatty acid contents increased after in vitro digestion in all emulsified lipids. Especially, free fatty acid content of emulsified lipid made from lard and olive oil were significantly higher than those of other emulsions after in vitro digestion.     

草鱼片热风干制过程中脂质氧化特性研究

探讨热风干燥过程中青鱼片油脂的变化情况。在青鱼片的不同干燥阶段提取油脂,检测油脂氧化程度,油脂成分及脂肪酸组成的含量变化。在干燥过程中鱼片油脂的过氧化值、羰基价和酸价显著性升高(P<0.05)。随着甘油三酯和磷脂含量的下降,游离脂肪酸含量明显增加,表明在干制过程中油脂在酯酶和磷酸化酶的催化下发生了水解反应。在总油脂和总磷脂中多不饱和脂肪酸,尤其是二十碳五烯酸(EPA)和二十二碳六烯酸(DHA)含量下降。在游离脂肪酸中,除DHA以外的多不饱和脂肪酸含量均显著升高。研究结果表明,青鱼片热风干燥过程中其油脂被氧化,同时发生脂质降解,特别是不饱和脂肪酸被释放为游离态。     

Formulation of a cosurfactant-free O/W microemulsion using nonionic surfactant mixtures

ABSTRACT:  A cosurfactant-free O/W microemulsion composed of oil, a mixture of hydrophilic and hydrophobic surfactants, and water has been developed using food-grade components as a nutrient delivery system. We started our investigation to monitor the phase behavior of this system based on a hydrophilic surfactant (Tween 80). From a phase diagram, the weight ratio of 5.4:33.8:60.8 = oil:surfactant:water was selected as a combination ratio for the O/W microemulsion system. We also investigated the combination effect of different hydrophobic surfactants to Tween 80 on microemulsion formation. Use of hydrophobic surfactants with Tween 80 produced smaller droplets than Tween 80 alone. Rheological studies showed that all microemulsions followed shear-thinning behavior. The turbidity of microemulsions did not change after accelerated stability tests, indicating that this microemulsion system was stable under the given harsh conditions. When docosahexaenoic acid (DHA) oil was applied to this microemulsion system, the particle size and the turbidity were not significantly changed. Dilution with a different aqueous medium, either water or acidic fluid, did not significantly change the microemulsion turbidity. DHA oil incorporated in microemulsion showed higher oxidation stability than free DHA oil.     

大豆乳清中分离干酪乳杆菌GJ00412的种子培养基优化

从大豆乳清中分离得到一株菌GJ00412,经16SrRNA基因测序、比对,初步鉴定为干酪乳杆菌,为降低种子培养基成本并提高其生物量,以便进一步应用,在传统乳酸杆菌(MRS)培养基基础上,采用响应面法对培养基组分进行优化。首先通过Plackett-Burman实验设计,从葡萄糖、大豆蛋白胨、酵母浸粉、胰蛋白胨、MgSO4、MnSO4、吐温80、p H等因素中,筛选出葡萄糖、酵母浸粉、MgSO4,吐温80和pH等5个对菌体生物量有显著影响的因子。采用响应面实验设计对上述5个因素进一步优化。优化后的培养基组成(w/v)如下:2.5%葡萄糖,1.8%大豆蛋白胨,0.4%酵母浸粉,0.08%MgSO4,0.04%MnSO4,0.08%吐温80,pH7.17。优化后的培养基与MRS培养基相比,降低成本,生物量无显著差异。     

Use of algae or algal oil rich in n-3 fatty acids as a feed supplement for dairy cattle

Fish oil is used as a ration additive to provide n-3 fatty acids to dairy cows. Fish do not synthesize n-3 fatty acids; they must consume microscopic algae or other algae-consuming fish. New technology allows for the production of algal biomass for use as a ration supplement for dairy cattle. Lipid encapsulation of the algal biomass protects n-3 fatty acids from biohydrogenation in the rumen and allows them to be available for absorption and utilization in the small intestine. Our objective was to examine the use of algal products as a source for n-3 fatty acids in milk. Four mid-lactation Holsteins were assigned to a 4×4 Latin square design. Their rations were supplemented with 1× or 0.5× rumen-protected (RP) algal biomass supplement, 1× RP algal oil supplement, or no supplement for 7 d. Supplements were lipid encapsulated (Balchem Corp., New Hampton, NY). The 1× supplements provided 29g/d of docosahexaenoic acid (DHA), and 0.5× provided half of this amount. Treatments were analyzed by orthogonal contrasts. Supplementing dairy rations with rumen-protected algal products did not affect feed intake, milk yield, or milk component yield. Short- and medium-chain fatty acid yields in milk were not influenced by supplements. Both 0.5× and 1× RP algae supplements increased daily milk fat yield of DHA (0.5 and 0.6±0.10g/d, respectively) compared with 1× RP oil (0.3±0.10g/d), but all supplements resulted in milk fat yields greater than that of the control (0.1±0.10g/d). Yield of trans-18:1 fatty acids in milk fat was also increased by supplementation. Trans-11 18:1 yield (13, 20, 27, and 15±3.0g/d for control, 0.5× RP algae, 1× RP algae, and 1× RP oil, respectively) was greater for supplements than for control. Concentration of DHA in the plasma lipid fraction on d 7 showed that the DHA concentration was greatest in plasma phospholipid. Rumen-protected algal biomass provided better DHA yield than algal oil. Feeding lipid-encapsulated algae supplements may increase n-3 content in milk fat without adversely affecting milk fat yield; however, preferential esterification of DHA into plasma phospholipid may limit its incorporation into milk fat.     

不同前体物质对破囊弧菌合成DHA影响的研究

DHA作为多不饱和脂肪酸系列中重要的一种,现已发现其对人类的许多疾病的治疗和预防有着重要的意义。目前它的分离纯化主要来自海洋鱼油,存在着许多不利因素限制其生产及应用,研究表明微生物具有大规模工业化生产DHA的能力。本文研究了不同植物油以及油酸、棕榈酸和硬脂酸对破囊壶菌D8发酵生产DHA的影响,发现棕榈酸对DHA的合成有明显的促进作用,发酵液中添加2％的棕榈酸可使破囊弧菌D8的DHA产量提高36．8％,达1554．01mg／L。     

原生态与人工添加二十二碳六烯酸羊乳制品贮藏期脂肪酸稳定性比较

通过饲喂奶山羊富含二十二碳六烯酸（docosahexaenoic acid，DHA）的微藻粉，获得原生态DHA羊乳（DHA含量为30 mg/100 g原料乳），然后将其制作成超高温瞬时灭菌（ultra-high temperature instantaneous sterilization，UHT）乳及全脂乳粉，同时设立人工添加富含DHA微胶囊粉的UHT乳及全脂乳粉作为对照组，在常温（25 ℃）和高温（37 ℃）下进行为期28 d的贮藏实验，研究原生态与人工添加DHA羊乳制品贮藏期脂肪酸稳定性。结果表明，与人工添加组相比，贮藏期间原生态UHT乳及全脂乳粉的DHA含量下降速率明显减缓，在UHT乳中，人工添加组乳制品DHA含量降低率在37 ℃下最高达（40.92±3.52）%（贮藏第28天），此时原生态组DHA降低率为（36.70±4.84）%。贮藏期间，原生态与人工添加DHA的UHT乳及全脂乳粉中多不饱和脂肪酸相对含量总体均下降，且与人工添加DHA的乳制品相比，原生态组中多不饱和脂肪酸相对含量更高，更易氧化生成碳链更短的脂肪酸。此外，随着贮藏期的延长，原生态DHA乳制品组中的油脂氧化指标过氧化值和酸价上升速率明显低于人工添加DHA乳制品组。综上，本实验可为制备富含DHA的天然奶制品提供理论参考。     

Effect of Non-Ionic Surfactants and Beta-Ionone on the Morphology of Blakeslea trispora and Carotenoids Production from Cheese Whey in Submerged Aerobic Growth: A Statistical Approach

The effect of non-ionic surfactants and β-ionone on morphology of Blakeslea trispora and carotenoids production from deproteinized hydrolyzed whey in submerged aerobic growth was investigated. Also, a central composite design was employed to determine the maximum carotenoids concentration at optimum values for the process variables (Tween 80, Span 80, β-ionone). The fit of the model was found to be good. Tween 80 and Span 80 had a strong linear effect on carotenoids production. The concentration of carotenoids was significantly affected by Tween 80 – Span 80 and Span 80 – β-ionone interactions as well as by the negative quadratic effect of β-ionone. The optimum medium composition for the maximum carotenoids production (100.0 ± 5.0 mg/g biomass dry weight) was found in deproteinized hydrolyzed whey supplemented with Tween 80 (33.6 g/L), Span 80 (68.7 g/L), and β-ionone (2.6 g/L). This result indicated that the optimization strategy led to an increase in carotenoids production by 33-fold. The carotenoids content in B. trispora were β-carotene, γ-carotene, and lycopene. The composition of carotenoids depends of the amount of nonionic surfactants and β-ionone added to the cheese whey. The medium composition influenced the morphogenesis of B. trispora and product formation. The addition of surfactants into the medium changed the morphology of the microorganism from solid aggregates to loose aggregates and resulted in a substantial increase in pigment production. B. trispora growing in submerged aerobic growth is able to develop complex morphologies which have been classified into three major groups: freely dispersed hyphae, clumps, and pellets. These parameters are responsible for the production of carotenoids.     

Effect of marination and smoking on lipid and fatty acid composition of thornback ray (Raja clavata) and spiny dogfish (Squalis acanthias)

The effects of different processing methods (marinated and smoked) on proximate compositions and fatty acids of thornback ray (Raja clavata) and spiny dogfish (Squalis acanthias) were investigated. Total lipid content was 3.39% in thornback ray and 5.90% in spiny dogfish. The lipids of raw fish consisted mainly of polyunsaturated fatty acids in thornback ray and saturated fatty acid in spiny dogfish. The n?3/n?6 ratio of thornback ray (3.78) was higher compared to spiny dogfish (2.87). After processing, water content decreased significantly while crude protein, lipid, and ash contents increased in both fishes. In general, processing techniques significantly (p?<?0.05) affected fatty acid fractions; in both species, SFA content increased, MUFA and PUFA content decreased. In addition, after processing n?3/n?6 ratios increased although total n?3 and n?6 contents decreased. The results indicated that heat treatment and acidic medium during processing had considerable affects on the proximate and fatty acid composition of the final products. Marinated and smoked products prepared from both fish species offer a balanced fatty acid composition for human nutrition. In terms of fresh and processed products, while the spiny dogfish appears to have a higher PUFA content, the thornback ray is a richer source of EPA?+?DHA.     

Direct Evidence That Maltose Transport Activity Is Affected by the Lipid Composition of Brewer's Yeast

A brewer's yeast strain was grown with maltose as sole carbon source under strictly anaerobic conditions with and without ergosterol and/or unsaturated fatty acid (Tween 80) supplements. Under all these conditions the MALx1 genes for maltose transporters were strongly expressed during growth. The fatty acid unsaturation indices of growing and stationary phase yeast were increased from about 20% to 56–69% by supplementation with Tween 80. Ergosterol contents were increased up to at least 4‐fold by supplementation with ergosterol and Tween 80. Maltose transport activity measured at 20°C was not increased by supplementation with Tween 80 alone, but was increased 2‐fold and 3‐fold, respectively, in growing and stationary phase yeast by supplementation with ergosterol together with Tween 80. The stimulation of maltose transport by ergosterol was greater when the transport was measured at temperatures (10°C and 0°C) lower than 20°C. The results show that proper function of maltose transporters requires adequate amounts of ergosterol in the yeast. This effect may partly explain the low maltose (and maltotriose) uptake rates both in the second half of brewery fermentations, when the sterol content of yeast has fallen, and when fresh wort is pitched with sterol‐deficient cropped yeast.     

On the Utilization of Microalgae for Brewery Effluent Treatment and Possible Applications of the Produced Biomass

The effluent of a brewery, complete or diluted with deionised water or with normal culture medium, was used as the growth nutrient medium for Chlorella vulgaris and for a consortium obtained from the autochthonous flora of that effluent (microalgae, cyanobacteria and bacteria). The cultures were exposed to continuous light and aeration, at 25°C, and growth was evaluated by direct counting (C. vulgaris) or by chlorophyll determination (autochthonous flora). Total protein and lipid content, and amino acid and fatty acid profiles in the produced biomass were determined. The highest removal rate of nutrients present in the effluent was obtained when the complete effluent was used as the culture medium for the autochthonous flora — up to 5,855 g kg^?1 biomass d^?1 of nitrogen and up to 805 g kg^?1 biomass d^?1 of phosphate. A reduction of up to 27% in biological oxygen demand (BOD5, initial level of 2,172 mg O₂ L^?1) and up to 15% in chemical oxygen demand (COD, initial level of 1,340 mg O₂ L^?1) was observed in cultures of the autochthonous flora grown in different loads of effluent. A significant increase in aspartic acid, glutamic acid and valine content, and a higher level of the ramified fatty acids, of the 14:0isobr, 18:4ω3, and the eicosapentaenoic acid, were found in the final biomass obtained from cultures grown with different loads of effluent, compared with the results obtained for the cultures grown in normal nutrient medium. The final microalgae biomass obtained, considering its protein and fatty acid content and the absence of heavy metals in significant amount, can be appropriate for use as animal feed or for biofuel production.     

Enriching the egg yolk in n − 3 fatty acids by feeding hens with diets containing horse fat produced in Uruguay

The present study was conducted to evaluate the ability of horse fat produced in Uruguay, compared with other lipid sources supplemented in the diet of laying hens, to modify the lipid composition and the n − 6/n − 3 fatty acid ratio of the produced eggs. For this purpose, 60 laying hens (Gallus domesticus) were fed for 30 days with five experimental diets (12 hens/diet) containing 3% sunflower oil (SO), rice oil (RO), beef tallow (BT), pressed-fat (PF), obtained by pressing fat from bovine viscera, and horse fat (HF) obtained from horse bone medulla. Throughout the trial, feeding rate, shell index, weight and total lipid contents of eggs, were not affected by the different diets. Feeding on the SO and RO diets significantly increased the amount of linoleic acid of the egg, although it was lower in the RO than in the SO eggs. Diet BT did not affect the saturated fatty acid content of the yolks. The diets with animal fats containing 18:3n − 3 (diets PF and HF), resulted in a significant increase in the n − 3 fatty acid contents of the eggs, through an increase of linolenic (18:3n − 3) and docosahexaenoic acid (DHA, 22:6n − 3) contents. Eggs from hens fed the HF diet showed increased linolenic acid (46 mg/yolk) and DHA (71 mg/yolk, 1.7% of total fatty acids) contents. These levels were obtained after two weeks of feeding. Moreover, the fatty acid profiles of eggs from treatment HF were not significantly affected by thermal treatment of the yolks. In conclusion, the fat from horse bone medulla, as produced in Uruguay, can be considered as a suitable lipid source for diets of laying hens, to modify the nutritional composition of the eggs in n − 3 PUFA content, especially DHA, and consequently, the n − 6/n − 3 fatty acid ratio.     

DHA营养强化鸡蛋与普通鸡蛋蛋黄脂质组成对比分析

以DHA营养强化鸡蛋及普通鸡蛋为原料,将鸡蛋煮熟后取出蛋黄,以体积比2∶1的氯仿-甲醇提取其中的脂质,分析总脂质含量、磷脂含量、总脂质的脂肪酸组成、磷脂的脂肪酸组成及分布以及中性脂(甘三酯和甘二酯)的脂肪酸组成及分布。结果表明:DHA营养强化鸡蛋蛋黄中的总脂质含量((29.28±1.70)%)与普通鸡蛋((32.46±0.34)%)无显著性差异(P> 0.05),总脂质中磷脂含量((102.13±1.57) mg/g)与普通鸡蛋((96.44±2.44) mg/g)无显著性差异(P> 0.05),DHA营养强化鸡蛋总脂质中DHA含量((11.14±0.18)%)远超普通鸡蛋((0.14±0.00)%),且DHA在磷脂中的含量((13.60±0.64)%)高于总脂质,在甘三酯((5.09±0.18)%)及甘二酯((1.88±1.13)%)等中性脂中含量较少;从空间位置分布来看,DHA在磷脂中各位置的分布无显著性差异,且DHA营养强化鸡蛋具有更佳的ω-3/ω-6比值。     

外源油脂的添加促进卷枝毛霉脂肪酸的积累

卷枝毛霉（Mucor circinelloides）可利用多种碳源实现脂质积累,不同的碳源对其脂质积累的影响不同。在不改变其它发酵培养条件和碳氮比的情况下,以100%葡萄糖为对照,添加不同比例的外源油脂（大豆油）作为另一种碳源,对其细胞生长和脂质生成的影响进行了研究。采用氯仿-甲醇法提取脂质,通过气相色谱技术（gas chromatography,GC）测定其脂肪酸组成及含量。同时,采用实时荧光定量PCR法检测了与脂肪酸合成相关的脱饱和酶基因在菌株中的表达情况。结果表明：碳氮比不变的情况下,最佳碳源混合比例为葡萄糖35 g/L,大豆油24.3 g/L,该培养基中生长的卷枝毛霉的生物量、脂质含量和脂质产量在发酵前期迅速增长,在发酵后期的增长趋势逐渐平缓,在发酵72 h之后略有下降,其最高生物量、脂质含量和产量分别为19.60 g/L、42.62%和8.35 g/L,而对照组（以葡萄糖为单一碳源）仅为14.72 g/L、34.41%和5.06 g/L。与对照组相比,经混合碳源培养的卷枝毛霉的生物量、脂质含量和产量分别提高了33.15%、23.8%和65.10%,且可以将大豆油中的α-亚麻酸...     

Effects of Tween 80 on the liquid fermentation of <Emphasis Type="Italic">Lentinus edodes</Emphasis>

This paper explored the effects of Tween 80 on the biomass, intracellular polysaccharide (IPS) content, fermentation parameters, the pellets size of mycelium, and the antioxidant activity of IPS in Lentinus edodes liquid fermentation. With adding to Tween 80, the outputs of biomass and IPS increased during the L. edodes fermentation, respectively, while the reducing sugar content was decreased, as well as, the time courses of pH value were different. It was also shown that the addition of Tween 80 could protect the intact of pellets from breaking down. The effects of Tween 80 on the main structure of IPS were no obvious, and the IPS were revealed similar infrared spectrum, as was indicated by the infrared spectrum analysis. Improvements in the scavenging capacity of DPPH radicals of IPS were observed in Tween 80 treated group compared with the control group. Tween 80 exerts impacts on the liquid fermentation of L. edodes.