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1.
Intramuscular fat (IMF) content is considered to be a key factor that affects the marbling, tenderness, juiciness and flavor of pork. To investigate the effects of myristic acid (MA) on the differentiation of porcine intramuscular adipocytes, cells were isolated from longissimus dorsi muscle (LDM) and treated with 0, 10, 50 or 100 μmol L-1 MA. The results showed that MA significantly promotes the differentiation of intramuscular adipocytes in a dose-dependent manner. MA also led to a parallel increase in the expression of peroxisome proliferator activated receptor-γ (PPARγ) and adipose-related genes, such as glucose transporter 1 (GLUT1), lipoprotein lipase (LPL), adipocyte fatty acid binding protein 4 (FABP4/aP2), fatty acid translocase (FAT), acetyl-CoA carboxylase α (ACCα), adipose triglyceride lipase (ATGL) and fatty acid synthase (FASN). However, no significant effects of MA were observed on the expression of CAAT enhancer binding protein-α (C/EBPα) or hormone sensitive lipase (HSL). The expression of pyruvate dehydrogenase kinase 4 (PDK4) was increased by MA during the early stages of differentiation (day 1-3). In addition, MA also increased the absolute content of C14 (P<0.001) and saturated fatty acids (SFA) (P<0.05) to varying degrees, but no effects were observed on other fatty acids. These results suggest that MA might be able to enhance the IMF content of pork and increase the accumulation of myristic and myristoleic acid in muscle, which might have beneficial implications for human health.  相似文献   

2.
The drying characteristics, physico-chemical and functional properties, as well as starch digestibility, of purple potato slices dried using different methods (such as, vacuum freeze-drying, VFD; hot-air drying, HAD; air-impingement jet drying, AIJD; and far-infrared assisted heat-pump drying, FIHPD) were investigated. Drying rate was the highest (3.0 g 100 g?1 min?1) using AIJD, followed by FIHPD and HAD, and the rate of VFD was the lowest one (0.3 g 100 g?1 min?1). Drying data were fitted to 12 thin-layer drying models, with the Midilli model giving the best predictions. Moreover, AIJD showed higher diffusivity (5.5×10?10 m2 s?1) and energy efficiency (55 J g?1) than any other drying method used in this study. With reference to the samples dried by VFD, the starch granules of the samples obtained by HAD, FIHPD, and AIJD exhibited different extent of disruption, which significantly increased their water absorption capacity, swelling power, and in vitro digestibility, but decreased the peak viscosity. The sample resulting from AIJD had the greatest water absorption capacity (7.9 g g?1) and solubility (21.6%), but the smallest syneresis rate (48%). Good correlation coefficients (R2>0.98) implied that the pseudo-first order kinetic model adequately described the rate and extent of starch digestion of dried potato flours. Samples from AIJD and FIHPD showed the highest digestibility percentages, reaching to 72.4 and 72.5%. Based on the drying rate, specific energy consumption, functional properties and digestibility, AIJD appeared to be quite effective and suitable to be transferred on the industry scale.  相似文献   

3.
Eleven grape cultivars were analysed to explore the variety differences of fresh grape phenolic profiles. The results showed that free phenolics were predominant in grape skins and pulps, and showed the higher antioxidant activities than bound. In 11 cultivars, Muscat Kyoho extracts had the highest total phenolic content in skins(10.525 mg GAE g~(–1) FW) and pulps(1.134 mg GAE g~(–1) FW), and exhibited the highest DPPH radical scavening capacity(EC_(50)=11.7 μg mL~(–1)) and oxygen radical absorbance capacity(ORAC) value(190.57 μmol TE g~(–1) FW) of free phenolic in skin. In addition, the most abundant phenolics in grape skins were found to be flavonoids such as kaempferol in Kyoho skin(541.2 μg g~(–1) FW), rutin, catechin and epicatechin in Muscat Kyoho skin(262.3, 86.3 and 70.0 μg g~(–1) FW, respectively). Furthermore, the principal component analysis showed a strong difference of phenolic profiles with the cultivars, existing forms and distributions. Pearson correlation coefficient analysis showed a significant linear correlation between total phenolic content and antioxidant activity(P0.05). Therefore, both skins and pulps were rich sources of bioactive phenolic compounds, and Muscat Kyoho was the ideal source among all samples.  相似文献   

4.
褐藻酸寡糖诱导下大豆营养成分的变化   总被引：1，自引：0，他引：1  
【目的】探索褐藻酸寡糖诱导大豆抗毒素生成和积累过程中,特别是当大豆抗毒素累积量达到最大时,大豆的异黄酮类化合物、氨基酸、寡糖、脂肪酸等营养成分的变化,为大豆的充分开发和利用提供科学依据。【方法】采用4%（w/v）的褐藻酸寡糖溶液作为诱导剂对大豆进行诱导。分别提取不同培养时间（0-6 d）下大豆中的异黄酮化合物、氨基酸、寡糖、脂肪酸等营养成分;利用高效液相色谱（HPLC）、全自动氨基酸分析仪、气相色谱（GC）等方法检测各培养时间下大豆营养成分的含量。【结果】经褐藻酸寡糖诱导后,大豆中的异黄酮化合物、氨基酸、寡糖、脂肪酸等含量均发生了变化。异黄酮类化合物中,大豆抗毒素的累积量在培养第5天时达到最高,由诱导前的0.01 mg·g-1升高至1.72 mg·g-1,第5天时香豆雌酚含量由开始时的15.74 μg·g-1升高至664.8 μg·g-1,染料木素含量由开始时的1.58 μg·g-1升高至24.03 μg·g-1,大豆苷元则由培养开始时的54.56 μg·g-1降低至19.02 μg·g-1。诱导组大豆中的总氨基酸含量由开始时的39.38%升高至43.45%,且苏氨酸、亮氨酸等必需氨基酸含量也有所升高,非诱导组大豆中的氨基酸含量也有一定程度的提高,但含量总体低于诱导组大豆。诱导组大豆中蔗糖含量由培养开始时的53.72 mg·g-1减少至21.5 mg·g-1,棉籽糖和水苏糖分别在培养第3天和第4天即被完全消耗;非诱导组大豆中蔗糖含量由培养开始时的53.72 mg·g-1减少至23.09 mg·g-1,且仍有少量的棉籽糖和水苏糖被检出。诱导组大豆中的脂肪酸总含量由培养开始时的14.27%降低至14.01%,但其中亚油酸的含量和比例有所增加。【结论】褐藻酸寡糖在诱导大豆获得最高大豆抗毒素含量时,增加了大豆中异黄酮类化合物含量,提高了大豆蛋白质的营养价值,消除了大豆中的胀气因子,并且在一定程度上提高了大豆的油脂品质。  相似文献   

5.
【目的】探索超声波辅助食盐腌制对牛肉脂肪酸组成的影响。【方法】以秦川牛肉为研究对象,研究测定超声波结合3%和6%食盐腌制后不同部位牛肉脂肪含量及脂肪酸含量。【结果】高档牛肉部位的脂肪含量较高,处理后高档牛肉的脂肪含量显著降低（P＜0.05）。经处理,不同部位不同脂肪酸含量的排序发生了明显变化,部分脂肪酸含量也随之发生了显著变化（P＜0.05）。其中,饱和脂肪酸含量变化不显著（P＞0.05）,但显著降低了月桂酸、肉豆蔻酸、15:0、17:0的含量（P＜0.05）,以月桂酸和17:0的差异最为明显;单不饱和脂肪酸含量变化也不显著（P＞0.05）,但显著降低了肉豆蔻油酸、反式棕榈油酸、棕榈油酸、17:1trans-9、17:1cis-9、反式油酸的含量（P＜0.05）,以17:1trans-9和17:1cis-9的差异最明显;多不饱和脂肪酸含量及其脂肪酸组成均显著增加（P＜0.05）,而且超声波辅助6%食盐处理效果更佳。【结论】超声波辅助低盐腌制对于降低秦川牛各部位牛肉脂肪的含量、提高牛肉多不饱和脂肪酸含量有明显的影响,为各部位牛肉加工提供了有利的理论依据。  相似文献   

6.
We developed a microplate assay method for determining the contents of triacylglycerols(TAGs), phosphatidylcholines(PCs), and free fatty acids(FFAs) in the rice bran of one grain using enzymatic reactions. In this method, enzymes from commercially available kits were used. Optimum reaction conditions were established. It was found that Nonidet P-40 was the optimal among the three surfactants used(Triton X-100, Tween 40, and Nonidet P-40) when lipid was dissolved in a reaction solution. Using this method, it was possible to quantify TAGs, PCs, and FFAs in concentration ranges of 7–150, 5–70, and 8–200 mg L~(–1), respectively. Furthermore, when the TAG contents in the rice bran were measured, the values closely corresponded to those obtained by extracting from large amounts of rice bran. However, sufficient data on the PC and FFA contents in rice bran are not available for valid comparisons. Although this method can accurately quantify the TAG contents in the rice bran of one grain, the accuracy of the PC and FFA contents has not been verified. Hence, future study is necessary.  相似文献   

7.
The total phenolic and flavonoid contents in the fruit tissues(peels,pulp residues,seeds,and juices)of 19 citrus genotypes belonged to Citrus reticulata Blanco were evaluated and their antioxidant capacity was tested by 2,2-diphenyl-1-picrylhydrazyl radicals(DPPH)method and 2,2′-azino-bis(3-ethylbenzthiozoline-6)-sulphonic acid(ABTS)method.The total phenolic and flavonoid contents,and their antioxidant capacity varied in different citrus fruit tissues.Generally,the peel had both the highest average of total phenolics(27.18 mg gallic acid equivalent(GAE)g~(–1 )DW)and total flavonoids(38.97 mg rutin equivalent(RE)g~(–1) DW).The highest antioxidant capacity was also the average of DPPH value(21.92 mg vitamin C equivalent antioxidant capacity(VCEAC)g~(–1 )DW)and average of ABTS value(78.70 mg VCEAC g~(–1) DW)in peel.The correlation coefficient between the total phenolics and their antioxidant capacity of different citrus fruits tissues ranged from 0.079 to0.792,and from–0.150 to 0.664 for the total flavonoids.The antioxidant capacity of fruit tissues were correlated with the total phenoilc content and flavonoid content except in case of the peel.In addition,the total phenolic content and antioxidant capacity varied in different citrus genotypes.Manju and Karamandarin were better genotypes with higher antioxidation and the phenolic content,however Shagan was the poorest genotype with lower antioxidation and the phenolic content.  相似文献   

8.
鸡皮中功能性极性脂质成分的分析研究   总被引：2，自引：1，他引：1  
[目的]以鸡皮为原料,分析研究对鸡皮极性脂质的功能性成分,为提取开发利用提供理论依据.[方法]硅胶柱层析法分离总脂质中的中性和极性脂质,利用双向薄层层析法进行极性脂质成分鉴定,气相色谱法分析脂质的脂肪酸组成.[结果]蛋鸡皮及肉鸡皮中脂质含量分别为31.8; 和40.5;,其中极性脂质分别占总脂质的1.8;和3.2;,主要是磷脂酰乙醇胺(脑磷脂PE),磷脂酰胆碱(卵磷脂PC),磷脂酰丝氨酸(PS), 鞘磷脂(SM)和磷脂酰肌醇(PI).总脂质的脂肪酸组成油酸(C18:1)含量最高,其次是棕榈酸(C16:0).蛋鸡皮的亚油酸(C18:2)含量高于肉鸡皮.极性脂质中主要的脂肪酸是C18:1,C18:2和C16:0,主要的甲基缩醛是十六二甲基缩醛和十八二甲基缩醛.[结论]肉鸡皮中极性脂质含量高于蛋鸡皮,主要由磷脂酰乙醇胺、磷脂酰胆碱、磷脂酰丝氨酸、鞘磷脂和磷脂酰肌醇组成.  相似文献   

9.
【目的】筛选具有较强脂质水解能力和抗氧化能力的发酵菌株,为研发新型发酵剂提供理论基础。【方法】在无菌猪肉浆体系中分别接种木糖葡萄球菌（Staphylococcus xylosus）YSZ11、YCC3,腐生葡萄球菌（Staphylococcus saprophyticus）YCC2,巨球菌（Macrococcus caseolyticus）YZC2、YZC3,并设立不接种发酵菌株为对照组（CK）,测定发酵4 d内猪肉浆pH、过氧化值（peroxide value,POV）、硫代巴比妥酸（thiobarbituric acid reactive substances,TBARS）值、脂肪酶活力、脂质组成和游离脂肪酸含量的变化。【结果】5株发酵菌株均可以降低猪肉浆体系的pH,POV和TBARS值分别为2.51—2.96 mmol·kg-1和0.21—0.24 mg/100 g,显著低于CK组（P<0.05）。在5组接种发酵菌株的猪肉浆中检测到了中性脂肪酶、酸性脂肪酶和磷脂酶3种酶活力,且后两者活性较高。发酵4 d后,接种发酵菌株组的磷脂含量显著降低（P<0.05）,游离脂肪酸含量增加了21.1%—73.7%,其中饱和脂肪酸总量显著降低,不饱和脂肪酸含量显著增加,尤其是棕榈油酸（C16:1）、油酸（C18:1）和亚油酸（C18:2）含量较高,并检测到亚麻酸（C18:3）。【结论】本试验中的5株菌株均可抑制脂质的氧化,同时可以分泌脂肪酶促进脂质的水解,增加游离脂肪酸特别是不饱和脂肪酸的含量。其中,腐生葡萄球菌YCC2和木糖葡萄球菌YCC3脂质水解和抗氧化能力较好,对改善发酵肉制品的品质具有更明显的促进作用。  相似文献   

10.
中华绒螯蟹在西藏高原条件下越冬期生化组分的变化   总被引：1，自引：0，他引：1  
分析了在西藏高原条件下驯养的中华绒螯蟹(Eriocheir sinensis)越冬期间生化组分及脂肪酸组成和含量的变化。结果表明:(1)越冬前后,中华绒螯蟹肝胰腺指数显著降低,由越冬前的11.72%降为越冬后的9.96%;(2)越冬后,肝胰腺中水分及干物质组分中的总脂和蛋白质相对含量显著下降;肌肉干物质中总脂和蛋白质相对含量也显著下降,但水分相对含量显著增加。肝胰腺和肌肉中的总糖相对含量在越冬前后均没有显著性差异;(3)脂类组分中,肝胰腺和肌肉中的游离脂肪酸(FA)和磷脂(PL)相对含量在越冬后都极显著降低;而肝胰腺中的甘油三酰(TG)相对含量显著升高,肌肉中磷脂的相对含量显著上升;(4)脂肪酸组分中,肝胰腺主要的饱和脂肪酸(SFA)C16∶0、C16∶1n7和单不饱和脂肪酸(MUFA)C18∶1n9和C18∶2n6在越冬期间作为主要能源物质被动员,消耗量均在10%以上;肌肉中SFA和MUFA作为能源被动员的情况和肝胰腺中的情况类似,但值得注意的是,肌肉中多不饱和脂肪酸(PUFA)中的C20∶5n3(EPA)、C22∶6n3(DHA)虽然在越冬后相对含量有明显上升,但由于肌肉中EPA和DHA的所占比例较高(分别占肌肉总脂的23.47%和12.38%),结合肌肉中总脂的消耗情况来看,在越冬期间EPA和DHA的绝对量是下降的,表明仍有较多的EPA和DHA被消耗;(5)越冬期间,肌肉中的蛋白质和肝胰腺中的脂类均被大量消耗,表明养殖的中华绒螯蟹已受到低温和饥饿的双重胁迫。如果要提高西藏高原地区养殖中华绒螯蟹越冬后的成活率,建议在越冬前做好其相关脂类和蛋白质的营养强化。  相似文献   

11.
This experiment was conducted to evaluate the effects of Bupleurum extract(BE) on blood metabolites, antioxidant status, and immune function in dairy cows under heat stress. Forty lactating Holstein cows were randomly assigned to 1 of 4 treatments. The treatments consisted of 0, 0.25, 0.5, and 1.0 g of BE kg–1 dry matter. Supplementation with BE decreased(P0.05) blood urea nitrogen(BUN) contents and increased blood total protein(TP) and albumin(ALB) levels compared with control cows, but it had no effects(P0.05) on blood glucose(GLU), nonesterified fatty acid(NEFA), total triglyceride(TG), low-density lipoprotein cholesterol(LDL-C), and high density lipoprotein cholesterol(HDL-C). Compared with control cows, cows fed BE had higher(P0.05) superoxide dismutase(SOD) and glutathione peroxidase(GSH-Px) activity. However, supplementation with BE had no effect(P0.05) on total antioxidant capacity(T-AOC) or malondialdehyde(MDA) levels. The immunoglobulin(Ig) A and G contents increased(P0.05) in cows fed 0.25 or 0.5 g of BE kg–1. Interleukin(IL)-2 and IL-4 levels were higher(P0.05) in cows fed 0.5 and 1.0 g of BE kg–1, and IL-6 was significantly elevated(P0.05) in cows fed 0.5 g of BE kg–1. There were no treatment effects(P0.05) on the CD4+ and CD8+ T lymphocyte ratios, CD4+/CD8+ ratio, or tumor necrosis factor-α(TNF-α) level among the groups. These findings suggest that BE supplementation may improve protein metabolism, in addition to enhancing antioxidant activity and immune function in heat-stressed dairy cows.  相似文献   

12.
对安康市木瓜属3个种（光皮木瓜［C. (Thouin.) Koehne．］、皱皮木瓜［C． speciosa (Sweet.) Nakai．］、毛叶木瓜［C．Cathayensis (Hemsl.) Schneid．］）果实含水量、粗蛋白质、粗脂肪、可滴定酸、可溶性固形物、粗纤维等主要营养物质进行测定。结果表明：安康市木瓜属3个种果实含水,差异不显著,均超过71%,变异系数小;粗蛋白质差异极显著,皱皮木瓜最大（3.95 g·100 g-1）,光皮木瓜最小（2.05 g·100 g-1）;粗脂肪差异极显著,毛叶木瓜最大（0.67 g·100 g-1）,光皮木瓜最小（0.37 g·100 g-1）;可滴定酸差异不显著,但变异系数大,毛叶木瓜可滴定酸含量最大（2.82 g·100 g-1）,光皮木瓜最小（1.84 g·100 g-1）;可溶性固形物差异显著,光皮木瓜可溶性固形物最大（12.67 g·100 g-1）,毛叶木瓜最小（8.67 g·100 g-1）;粗纤维差异极显著,光皮木瓜最大（19.68 g·100 g-1）,毛叶木瓜最小（1.02 g·100 g-1）。对安康市木瓜属3个种果实主要营养成分测定分析,为木瓜属植物选育和产品加工提供依据,对木瓜属植物开发利用具有十分重要的意义。  相似文献   

13.
血液和组织标本中脂肪酸组成的毛细管柱气相色谱分析   总被引：3，自引：0，他引：3  
用氯仿甲醇抽提、三氟化硼－乙醚甲醇酯化，然后利用毛细管柱和程序升温的方法进行气相色谱分析，建立了血浆和红细胞膜总脂以及组织磷脂和中性脂脂肪酸组成的毛细管柱气相色谱分析法。图谱表明各峰间分离效果良好、峰形尖锐、干扰少。各种脂肪酸的最小检测限均可达１０－（－１１）ｇ／ｓ，ＦＩＤ对各脂肪酸的响应均呈线性。实验重复性好，回收率达定量分析要求．  相似文献   

14.
茶籽中油脂的脂肪酸组成测定(英文)   总被引：2，自引：0，他引：2       下载免费PDF全文
选取24个茶树品种的茶籽,研碎,用甲醇和氯仿提取其中的脂肪,将提出的脂肪甲基化,用100m×0.25 mm的CP-Sil88毛细管柱测定脂类中的脂肪酸组成.结果显示:茶籽的脂肪中主要含有20种脂肪酸,不饱和脂肪酸为主要成分;单不饱和脂肪酸的平均含量为51.06%,其中油酸占单不饱和脂肪酸量的96.4%,多不饱和脂肪酸平均含量为27.86%,主要为亚油酸,占多不饱和脂肪酸量的98.6%;饱和脂肪酸平均含量为20.67%,主要为棕榈酸和硬脂酸,分别占饱和脂肪酸的78.3%和19.3%;此外还含有0.144%18:1-11t酸,该种脂肪酸在人体内可能是9c,11t-CLA(顺-9,反-11-共轭亚油酸)的前体.说明茶籽油的脂肪酸组成较符合保健食用油标准.  相似文献   

15.
Fat tissue is the most important energy depot in vertebrates. The release of free fatty acids (FFAs) from stored fat requires the enzymatic activity of lipases. We showed that genetic inactivation of adipose triglyceride lipase (ATGL) in mice increases adipose mass and leads to triacylglycerol deposition in multiple tissues. ATGL-deficient mice accumulated large amounts of lipid in the heart, causing cardiac dysfunction and premature death. Defective cold adaptation indicated that the enzyme provides FFAs to fuel thermogenesis. The reduced availability of ATGL-derived FFAs leads to increased glucose use, increased glucose tolerance, and increased insulin sensitivity. These results indicate that ATGL is rate limiting in the catabolism of cellular fat depots and plays an important role in energy homeostasis.  相似文献   

16.
Two experiments, a Petri dish assay and a pot experiment were carried out to evaluate possible allelopathic effects of water extracts (0, 10 and 20 g L?1) of sugar beet (Beta vulgaris) and eucalyptus (Eucalyptus camaldulensis) on germination and growth of purslane (Portulaca oleracea). Results showed that germination percentage of purslane seeds was not inhibited by concentration of water extract of test plants. However, seed vigour and seedling growth strongly influenced by aqueous extracts of test plants. Maximum inhibitions on seedling growth were recorded when using the highest concentration of the aqueous extract (20 g L?1). It was apparent that sugar beet had a greater inhibitory effect than eucalyptus. Shoot length of purslane seedlings significantly decreased at 10 and 20 g L?1 aqueous extract concentration of sugar beet by 65.5 and 92.1% respectively compare to control, while eucalyptus decreased seedling shoot length of target weed at 10 and 20 g L?1 extract concentration by 29.8% and 52.9% respectively. Root length was more affected than shoot so that low aqueous extract concentration (10 g L?1) of sugar beet and eucalyptus decreased root length of target weed by 79.8% and 46% respectively. Foliar sprays with both 10 and 20 g L?1 of test plants extracts significantly decrease leaf area, leaves, stem and root dry weight of Portulaca oleracea. Maximum leaf area (1010 cm2) was obtained from the untreated plants (0% extract), while the lowest value (166.6 cm2) occurred with 20 g L?1 water extract of sugar beet. High aqueous extract concentration (20 g L?1) of sugar beet decreased leaves, stem and root dry weight of purslane plants by 96%, 86.7% and 91.9% respectively.  相似文献   

17.
为探究即食虾干加工过程中脂质的变化情况，以凡纳滨对虾为研究对象，分别取鲜虾、煮后、干燥2 h、干燥4 h的样品，对总脂含量、脂质组成、脂肪酸组成、酸价（Acid value, AV）、过氧化值（Peroxide value, POV）、硫代巴比妥酸反应值（Thiobarbituric acid reactive substances, TBARS）进行了检测分析。结果表明，鲜虾总脂含量为8.74 g/100 g（干基计），在煮制和干制过程中变化不显著（P>0.05）。脂质组成发生明显变化，煮后甘油三酯和游离脂肪酸的比例显著降低（P＜0.05），而磷脂比例显著升高（P＜0.05）。在干制过程，磷脂比例呈下降趋势，游离脂肪酸比例呈上升的趋势，而胆固醇比例相对稳定。脂肪酸组成在加工过程总体变化较小，其中多不饱和脂肪酸在干制阶段含量有所减少，相对的提高了饱和脂肪酸含量。虾干加工过程中，POV呈先上升后下降的变化趋势，AV在煮后急剧下降，而干制后增加，TBARS一直上升。由此，虾干加工过程中煮制和热风干燥会影响脂质组分的比例，同时引起脂质的氧化分解。本研究为即食虾干加工工艺的优化、品质控制及风味形成提供了理论参考。  相似文献   

18.
龙眼乳酸菌发酵工艺条件优化及其挥发性风味物质变化   总被引：1，自引：0，他引：1  
【目的】建立龙眼乳酸菌发酵的优化工艺条件,明确乳酸菌发酵前后其挥发性风味物质的变化,为龙眼功能性饮料的开发提供指导。【方法】采用梯度浓度驯化法将乳酸菌（保加利亚乳杆菌﹕嗜热链球菌=1﹕1）依次接入到含60%、70%、80%、90%（质量分数）龙眼果浆和10%脱脂乳的混合物中进行驯化,分析驯化过程中龙眼果浆酸度和pH的变化;以总酸为指标,通过Box-Benhnken中心组合试验设计优化乳酸菌发酵龙眼果浆的工艺条件,建立包括发酵时间、发酵温度、脱脂奶粉添加量和接种量的4因素回归模型;采用顶空固相微萃取和气相色谱-质谱联用的方法分析龙眼果浆发酵前后主要挥发性风味物质变化。【结果】（1）经过梯度浓度驯化后,得到了能在高浓度龙眼果浆中发酵的乳酸菌,经过12 h发酵,90%龙眼果浆的酸度由9.5 ºT升至104.4 ºT,pH由7.12降至4.44,其酸度显著高于60%和70%的龙眼果浆（P<0.05）,而pH与60%、70%和80%龙眼果浆无显著差异（P>0.05）。（2）经回归模型并结合验证试验,确定乳酸菌发酵龙眼果浆的最佳工艺条件为：发酵时间12 h、发酵温度45℃、脱脂奶粉添加量5%、接种量3%。在该条件下,龙眼果浆的酸度由发酵前的9.5 ºT升为105.1 ºT,与模型预测值的相对误差为1.2%,可用于实际生产中预测。（3）龙眼果浆经乳酸菌发酵后其挥发性风味物质发生了显著变化。共有53种挥发性物质被检测出,其中萜烯烃类15种、醇类6种、酯类18种、酮类7种、醛类3种、酸类2种以及其他类2种。与发酵前相比,龙眼果浆发酵后新产生了18种挥发性风味物质。发酵后醇类、醛类、酯类、酮类和酸类挥发性风味物质的含量呈增加趋势,而萜烯烃类含量呈降低趋势。乳酸菌发酵龙眼果浆主要挥发性风味物质为乙醇25.68 μg·g-1、4-（1-甲基乙基）-苯甲醇2.42 μg·g-1、乙醛1.95 μg·g-1、苯甲醛1.25 μg·g-1、乙酸乙酯2.19 μg·g-1、苯甲酸甲酯1.05 μg·g-1、水杨酸甲酯1.93 μg·g-1、3-羟基-2-丁酮1.085 μg·g-1、反式-罗勒烯97.81 μg·g-1、别罗勒烯1.923 μg·g-1、乙酸1.84 μg·g-1,其中苯甲醛和乙酸乙酯由发酵产生,乙醇、乙醛、别罗勒烯及乙酸经发酵后含量增加。【结论】乳酸菌发酵显著增加龙眼果浆的总酸及挥发性风味物质,通过优化控制发酵条件,可以开发风味独特的龙眼乳酸菌饮料新产品。  相似文献   

19.
Five lactating Holstein cows in a 5×5 Latin square experiment were fed five high-concentrate total mixed rations(TMRs) to investigate the effects of step-wise improvement of forage combination on ruminal and milk fatty acid profiles. The ratio of concentrate to forage was fixed as 61:39, and the step-wise improvement of forage combination was applied as: TMR1, a ration containing corn stover; TMR2, a ration containing corn stover and ensiled corn stover; TMR3, a ration containing ensiled corn stover and Chinese wild ryegrass hay(Leymus chinensis); TMR4, a ration containing the ryegrass hay and whole corn silage; TMR5, a ration containing the ryegrass hay, whole corn silage and alfalfa hay. The TMRs were offered to the cows twice daily at 0700 and 1900 h. The entire experiment was completed in five periods, and each period lasted for 18 days. Diurnal samples of rumen fluids were collected at 0100, 0700, 1300 and 1900 h(day 16); 0300, 0900, 1500 and 2100 h(day 17); and 0500, 1100, 1700 and 2300 h(day 18). The step-wise improvement of forage combination increased energy and crude protein contents and decreased fibre content. As a result, the step-wise improvement of forage combination increased dry matter intake and milk yield(P0.05). The step-wise improvement increased dietary content of linolenic acid(C18:3 n-3), but did not alter dietary proportions of palmitic acid(C16:0), stearic acid(C18:0), oleic acid(C18:1 cis-9), linoleic acid(C18:2 n-6) and arachidic acid(C20:0). In response to the forage combination, ruminal concentration of C16:0, C18:2 n-6 and C18:3 n-3 linearly increased against their dietary intakes(P0.10). The step-wise improvement increased milk contents of C10:0, C12:0, C14:0, C16:0, C18:2 n-6 and C18:3 n-3(P0.10) and decreased milk contents of C18:0 and C18:1 cis-9(P0.05). Milk yields of C16:0, C18:1 cis-9, C18:2 n-6 and C18:3 n-3 were linearly increased by the increase of these fatty acids in the rumen(R2≥0.79, P0.05), and milk yields of C18:2 n-6 and C18:3 n-3 were also positively correlated with dietary intake of these fatty acids(R2≥0.85, P0.05). The step-wise improvement increased the transfer efficiencies from feed to milk for C18:2 n-6 from 11.8 to 14.2% and for C18:3 n-3 from 19.1 to 22.3%. In a brief, along with the step-wise improvement of forage combination, more dietary linoleic and linolenic acids might escape microbial hydrogenation in the rumen and consequently accumulated in milk fat though these fatty acids were present in low concentrations in ruminal fluids. The step-wise improvement of forage combinations could be recommended as a dietary strategy to increase the transfer efficiency of linoleic and linolenic acids from feed to milk.  相似文献   

20.
In this study, the characteristic of three transformants named as B1 C106-1, B1 C106-2, and B1 C106-3 were studied that carried three innate resistant genes Bph14, Bph15, and Xa23, and two enthetic resistant genes Cry1 Ca# and Bar. The five resistant genes were all verified by PCR and the two enthetic genes were identified in single copy insertion by Southern blot. At tillering stage, the Cry1 C and PAT(phosphinothricin acetyl transferase) protein contents in leaf, sheath, and stem of T2 generation were in the similar pattern: leafstemsheath, and showed significant difference(P0.01) among three organs. The average contents of Cry1 C protein in plant of B1 C106-1, B1 C106-2, and B1 C106-3 were 12.95, 6.57, and 11.30 μg g–1, respectively, and showed significant difference(P0.01) among them. However, the average contents of PAT in plant of B1 C106-1, B1 C106-2, and B1 C106-3 were 28.54, 27.66, and 28.02 μg g–1, respectively, and there were no significant difference among three transformants. The glufosinate tolerable concentration of three transformants of T3 generation reached at least 6 g L–1, and the mortality of rice leaf rollers were above 97.4% in 5 days after being fed with fresh transformants' leaves. The Cry1 C protein toxicity was also assessed by silkworms, and the mortality of silkworms feeding mulberry leaves smeared with Cry1 C protein extracts of leaves of B1 C106-1, B1 C106-2, and B1 C106-3 were 90, 67.8, and 87.8%, respectively, that were positive correlation(r=0.993) with Cry1 C protein contents in plant of three transformants. The three transformants also maintained high resistance to brown planthopper and bacterial blight as the original version. The above results indicate the tetra-resistant rice germplasm was well-developed by pyramiding innate and enthetic resistant genes in an elite line to provide with resistances of glufosinate, rice leaf roller, brown planthopper, and bacterial blight.  相似文献   

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