食品中脂肪的感官机制研究进展

近年来,随着现代社会人群对健康低脂食品以及感官享受需求的增长,探索既减少食品中多余脂肪含量,又增加脂肪的感官评价的方法,成为食品工业面临的重大课题。目前对食品中脂肪感官机制的研究日渐重要。本文概述了近年来学术界对食品中脂肪的滋味和质构感官机制的研究进展,归纳脂肪感官的测评方式,以期为研究人员和食品工业界提供一些思路。

酵母抽提物成分分析及其代脂作用研究

为深入研究酵母抽提物功能成分及其酵母抽提物提升植脂末脂肪感作用,本文在分析降脂专用酵母抽提物氨基酸组分、GC-MS、肽分子量分布等成分研究基础上,开发含酵母抽提物的植脂末配方和工艺,最后利用酵母抽提物替代部分植脂末,达到降脂和口感提升的目的,结果显示酵母抽提物具有替代植脂末脂肪感的作用。

Developmental Changes of the FAS and HSL mRNA Expression and Their Effects on the Content of Intramuscular Fat in Kazak and Xinjiang Sheep

Twenty-four male Kazak sheep and 30 Xinjiang fine wool sheep at different ages were selected to investigate the development-dependent expression levels of fatty acid synthase （FAS） gene and hormone-sensitive lipase （HSL） gene in muscle and their effects on the contents of intramuscular fat （IMF）. Longissimus dorsal muscle was sampled to measure IMF and total RNA was extracted to determine FAS and HSL mRNA expression levels by real-time PCR. The results showed that： l） The IMF content increased continuously with growth and showed significant differences （P 〈 0.05） between different age groups in male Kazak sheep, but in Xinjiang fine wool sheep there was no such difference observed. Furthermore, the IMF contents in Kazak were much higher （P 〈 0.01） than that of the other breed from day 30 to 90. 2） FAS mRNA expression level was the highest （P 〈 0.05） on day 0 in Kazak sheep and then declined with growth, in the other breed the gene showed a d‘ecline-rise-decline-rise＇ expression manner as the animals grew. HSL mRNA expression level had a similar model in two breeds, in Kazak sheep it was the highest on day 0 （P 〈 0.05） and in Xinjiang fine wool sheep on day 30 （P 〈 0.01）, then both decreased after this term. 3） In male Kazak sheep, FAS and HSL mRNA expression level were both negatively related to IMF content （r= -0.485 （P = 0.02）, r= -0.423 （P = 0.05））, and the ratio of FAS/HSL expression exhibited significantly negatively related IMF contents. In male Xinjiang sheep, there were no obvious relationship between FAS and HSL expression and IMF content （P 〉 0.05）.

Fatty Acid Synthase and Hormone-sensitive Lipase Expression in Liver Are Involved in Zinc-α2-glycoprotein-induced Body Fat Loss in Obese Mice

Objective To explore the effects of zinc-0t2-glycoprotein （ZAG） on body weight and body fat in high-fat-diet （HF1））-induced obesity in mice and the possible mechanism. Methods Thirty-six male mice were fed with standard food （SF） （n=9） and HFD （n=27）, respectively. Five weeks later, 9 mice fed with HFD were subjected to ZAG expression plasmid DNA transfection by liposome transfection method, and another 9 mice to negative control plasmid transfection. Two weeks later, serum ZAG level in the mice was assayed by Western blot, and the effects of ZAG over-expression on body weight, body fat, serum biochemical indexes, and adipose tissue of obese mice were evaluated. The mRNA expressions of fatty acid synthase （FAS） and hormone sensitive lipase （HSL） in liver tissue were deterlnined by reverse transcription-polymerase chain reaction. Results Serum ZAG level significantly lowered in simple HFD-fed mice in comparison to SF-fed mice （0.51±0.10 AU vs. 0.75±0.07 AU, P〈0.01）. Further statistical analysis demonstrated that ZAG level was negatively correlated with body weight （r =-0.56, P〈0.001）, epididymal fat mass （r=-0.67, P〈O. 001）, percentage of epididymal fat （r= 0.65, P〈0.001）, and increased weight （r= 0.57, P〈0.001） in simple SF- and HFD fed mice. ZAG over-expression in obese mice reduced body weight and the percentage of epididyreal fat. Furthermore, FAS mRNA expression decreased （P〈0.01） and HSL mRNA expression increased （P〈0.001） in the liver in ZAG over-expressing mice. Conclusions ZAG is closely related to obesity. Serum ZAG level is inversely correlated with body weight and percentage of body fat. The action of ZAG is associated with reduced FAS expression and increased HSL expression in the liver of obese mice.

EFFECTS OF SIMVASTAIN COMBINED WITH OMEGA-3 FATTY ACIDS ON HIGH SENSITIVE C-REACTIVE PROTEIN, LIPIDEMIA, ANDFIBRINOLYSIS IN PATIENTS WITH MIXED DYSLIPIDEMIA

Objective To evaluate the effects of simvastatin combined with omega-3 fatty acids on high sensitive C-reactive protein(HsCRP), lipidemia, and fibrinolysis in coronary heart disease (CHD) and CHD risk equivalent patients with mixed dyslipi-demia. Methods A randomized, double-blind placebo controlled and parallel group trial was conducted. Patients with CHD and CHD risk equivalents with mixed dyslipidemia were treated with 10 or 20 mg simvastatin for 6-12 weeks. Following with the treatment of patients whose low-density lipoprotein cholesterol (LDL-ch) reaching goal level (< 100 mg/dL) or close to the goal (< 130 mg/dL), while triglyceride (TG) ≥200 mg/dL and < 500 mg/dL, was combined with omega-3 fatty acids (3 g/d) or a placebo for 2 months. The effects of the treatment on HsCRP, total cholesterol (TC), LDL-ch, high-density lipoprotein cholesterol (HDL-ch), TG, lipoprotein (a) [LP (a)], apolipoprotein A1 (apoA1), apolipoprotein B (apoB), plasminogen activator inhibitor-1 (PAI-1), and tissue plasminogen activator (tPA) were investigated. Forty patients finished the study with each group consisting of twenty patients. Results (1) There were significant reductions of HsCRP, TG, TC, and TC/HDL-ch, which decreased by 2.16 ±2.77 mg/L (38.5%), 94.0 ±65.4 mg/dL (31.1%), 13.3 ±22.3 mg/dL (6.3%), 0.78 ±1.60 respectively in the omega-3 fatty acids group (P< 0.01, < 0.001, < 0.05, < 0.05) compared to the baseline. HsCRP and triglyceride reduction were more significant in omega-3 fatty acids group compared to the placebo group (P=0.021 and 0.011 respectively). (2) In the omega-3 fatty acids group, the values and percentage of TG reduction had a significantly positive relation with HsCRP reduction (r=0.51 and 0.45, P=0.021 and 0.047 respectively). Conclusion In CHD and CHD risk equivalent patients with mixed dyslipidemia, dyslipidemia’s therapeutic effect using simvastatin and omega-3 fatty acids may result from not only the combination of lipid adjustment, but also enhancement of their own nonlipid influences.

The Related Research of the Genes of Gibberellin Receptor(GID1) in Plant

The hormone gibberellin(GA) plays an important role in modulating diverse processes throughout plant development.Gibberellin(GA) perception is mediated by GID1(GA-INSENSITIVE DWARF1),a receptor that shows similarity to hormone-sensitive lipases.It has been postulated that plants have two types of GA receptors,including soluble and membrane-bound forms.In recent years,significant advances have been made in the research of Gibberellin Receptor(GID1).This article highlights recent advances in the molecular structure of Gibberellin Receptor(GID1),Molecular Interactions between the Gibberellin Receptor(GID1) with DELLA,Cloning and expression of GA receptors(GID1),function identification of GA receptor gene(GID1).These discoveries open new prospects for the understanding mechanism of GA receptors(GID1) in plants.

Mechanisms and significance of liver steatosis in hepatitis C virus infection

The pathogenesis of liver damage associated with chronic hepatitis C virus （HCV） infection is thought to be largely immunomediated. However, some frequent histoo pathological features, such as steatosis, suggest a direct cytopathic effect of HCV. The direct responsibility of HCV in the pathogenesis of steatosis is shown by： （1） the association with HCV genotype 3 infection, suggesting that some viral sequences are involved in the intracellular aco cumulation of lipids; （2） the correlation between severity of steatosis and HCV replication levels; （3） association between response to treatment and disappearance of steatosis. Experimental studies have shown that the nuo cleocapsid protein of HCV （core protein） is capable and sufficient to induce lipid accumulation in hepatocytes. Moreover, the observation that chronic hepatitis C pao tients have reduced serum levels of ApoB suggests an interference with the very-low density lipoprotein （VLDL） assembly, although other mechanisms are possible. In patients with sustained virological response induced by antiviral therapy, such levels are normalized. Other obo servations suggest that the pathogenesis of steatosis in chronic hepatitis C is not solely due to HCV. The origin of the mild steatosis observed in most patients may be metabolic, since its severity correlates with body mass index and insulin resistance. Most studies have shown a correlation between presence and/or severity of steatosis and fibrosis stage, but it is unclear whether this effect is direct or mediated by the associated insulin resistance, increased susceptibility to apoptosis, or by inflammao tory cytokines. Finally, steatosis negatively influences the rate of response to antiviral treatment, as confirmed by large clinical trials. Management of steatosis in chronic hepatitis C requires knowledge of its pathogenesis and may involve both life-style changes and pharmacological interventions, although the latter remain largely experio mental.

Effect of Various Sources of Fat Ingredients on the Properties of Goat Milk Ice Cream

Goat milk ice cream was made with various sources of fat ingredients such as cream, soybean oil, rice bran oil and butter with the purpose of seeking the fat ingredient source instead of fat source from cow origin. The physical properties and the sensory evaluation of ice cream were then investigated. The firmness of goat milk ice cream mixed with rice bran oil, butter and cream were not significantly different before aging at 4 ℃ for 8 h. All of them gave the overrun between 51%-63% and the one with butter was the highest. The meltdown rate of all types of fat ingredients are not significantly different, being in the range of 0.86-0.88 g/min. According to sensory evaluation, the cow milk ice cream with cream was mostly accepted in all attributes such as appearance, smoothness, whiteness, melting in mouth and odor while the goat milk with cream and butter are the second and third. Nevertheless, the goat milk ice cream with soybean oil and rice bran oil were moderately accepted in overall preferences.

Effect of Dietary Fat Sources on the Fatty Acid Composition and Sensory Characteristics of Chicken Meat

The research was carried out in two experiments on Ross 308 male hybrid chickens. Chickens were divided into five groups （five dietary treatments differing in source and concentration of plant oil and fish oil）. Feeding chickens with diets of determined composition from 22nd to 42nd day of fattening resulted in altered fatty acid profile in white meat and dark meat, and in significantly lowered n-6/n-3 polyunsaturated fatty acids （PUFA） ratio in white meat. Increase of n-3 PUFA concentration in diets resulted in statistically significant （P = 0.001） increase of n-3 PUFA, as well as in decrease （P = 0.02） of n-6 PUFA in white and dark chicken meat in the 1 st experiment. The 2nd experiment resulted in statistically significant increase of n-3 PUFA concentration in white and dark chicken meat （P 〈 0.001）, and n-6 PUFA concentration decreased only in dark chicken meat （P 〈 0.001）. The increase of PUFA in both experiments was accompanied with decrease of saturated fatty acids （SFA） concentration in chicken meat. Although all experimental treatments were assessed as having more fishy odour and flavour than the control sample, statistically significant difference between samples was found only for fishy flavour in dark meat （P 〈 0.05）. In the 2nd experiment, where the feeding treatment was altered seven days before chickens＇ slaughtering （fish oil was omitted）, the intensity of fishy odour and flavour was assessed with ＂none＂ to ＂slightly noticeable＂ （P 〉 0.05）. In order to produce chicken meat as functional product, it is possible to reach balance between high n-3 PUFA concentration and satisfactory sensory traits characteristics of chicken meat.

Dangfei Liganning Capsules (当飞利肝宁胶囊) Attenuate the Susceptibility of Rat Nonalcoholic Fatty Liver to Carbon Tetrachloride Toxicity

Objective: To test whether nonalcoholic hepatic steatosis sensitizes carbon tetrachloride (CCl4)-induced liver injury, and to assess the therapeutic effect of Chinese medicine extracts of Dangfei Liganning capsules (当飞利肝宁胶囊) and their potential underlying mechanisms. Methods: Male Wistar rats were fed a high-fat diet to induce nonalcoholic fatty liver disease (NAFLD) or a normal diet (N). Eight weeks later, a nonlethal dose of CCl4 was applied intraperitoneally. From the start, HF-CCl4 rats were administered daily Dangyao extracts (D), Dangfei Liganning capsules (DF), or Diammonium Glycyrrhizinate (G) intragastrically. Rats were sacrificed 48 h after CCl4 administration. In addition to serum biochemistry, liver histopathology was observed using hematoxylin-eosin (HE) and oil red O staining, and hepatic levels of triglyceride (TG), malondialdehyde (MDA), glutathione (GSH), superoxide dismutase (SOD), caspase-3 activation and cytochrome P450 (CYP2E1) expression were assessed. Results: There was almost no response to the nonlethal dose of CCl4 in the N control group. However, the HF group demonstrated massive steatosis, and elevated levels of serum ALT and AST, liver MDA, CYP2E1, and caspase-3 activation, whereas the levels of GSH and SOD were significantly decreased. All indexes assessed were dramatically worse in the HF-CCl4 group compared to the HF group, in addition to the more severe steatosis, hepatocyte ballooning, and inflammatory infiltration apparent in the centrilobular area. The medicines we tested affected the pathological changes in HF-CCl4 rats to differing degrees: DF and G led to improvements in all of the above examined indexes, including an obvious improvement in histopathology, and DF improved serum ALT and MDA levels more markedly than G, whereas D extracts produced only mild liver injury attenuation. Conclusion: Liver with NAFLD is more sensitive to hepatotoxicity; furthermore, the disrupted balance of oxidative stress and anti-oxidant defense contributes to the underlying mechanisms. Dangfei Liganning capsules potentially decrease this toxic susceptibility and alleviate liver injury in non-alcoholic fatty liver.

The role of visceral adipose tissue on improvement in insulin sensitivity following Roux-en-Y gastric bypass:a study in Chinese diabetic patients with mild and central obesity

Background:Most Chinese patients with type 2 diabetes mellitus(T2DM)have mild obesity and central obesity.Central obesity is combined with insulin resistance.The aim of this study was to assess the effect of abdominal adipose tissue on insulin-sensitivity improvement after Roux-en-Y gastric bypass(RYGB)in Chinese diabetic patients with mild and central obesity.Methods:Seventeen T2DM patients with a mean body mass index of 30.3 kg/m^(2) were scheduled for laparoscopic RYGB.A hyperinsulinemic-euglycemic clamp and dual-energy X-ray absorptiometry were performed prior to surgery and 3 months after RYGB.The primary end points were the correlations between insulin sensitivity and abdominal adipose tissue,including visceral adipose tissue(VAT)and subcutaneous adipose tissue(SAT),before and 3 months after RYGB.Results:Indices of peripheral insulin sensitivity,including glucose-disposal rate(M value)and glucose infusion rate,were significantly increased after RYGB.Body-fat mass,VAT and SAT were significantly reduced after RYGB.The pre-operative M value was significantly correlated with VAT mass(r=–0.57,P=0.02),but not correlated with SAT mass.M value changes after RYGB were highly correlated with changes in VAT mass(r=–0.59,P=0.01),percentage of VAT mass(r=–0.66,P<0.01),VAT area(r=–0.56,P=0.02)and percentage of VAT area(r=–0.57,P=0.02).Conclusions:A significant correlation was observed between increased peripheral insulin sensitivity and decreased VAT following RYGB in Chinese patients with mild and central obesity.VAT and SAT were significantly decreased with improved insulin sensitivity after RYGB.VAT mass may be considered as an indication for gastric bypass during patient selection.

Treatment analysis of acute fatty liver of pregnancy complicated with hematogenous infection of CRKP

Acute fatty liver of pregnancy(AFLP)is an idiopathic disease with acute and critical onset.Although the incidence of AFLP is relatively low,its mortality remains high.When AFLP is complicated with multi-organ dysfunction syndrome(MODS)and severe infection,especially hematogenous infection caused by multidrug-resistant pathogens,treatment becomes extremely difficult with an even lower survival rate.In the present work,we reported a 31-year-old primipara woman who developed AFLP complicated with MODS and severe infection at 37+5 weeks of gestation and received treatment in our hospital.The result of fast blood culture was positive for carbapenem-resistant Klebsiella pneumonia(CRKP).Based on this finding in combination with the results of drug sensitivity test,the quadruple regime using scheme imipenem cilastatin sodium,tigecycline,polymyxin and fosfomycin was implemented,and the patient was successfully cured.Successful treatment of pregnant women with AFLP complicated with MODS and/or hematogenous infection of CRKP can be achieved by using individualized combined antibiotic therapies on the basis of fast blood culture and combined drug sensitivity test.In this case,the patient was in a critical situation.In the treatment process,clinicians,clinical pharmacists and microbiologists should cooperate with each other and discuss the treatment plan together according to the pathophysiological characteristics of the patient,which was one of the key factors for successful treatment of the patient.

Ultrasensitive detection of aliphatic nitro-organics based on“turn-on”fluorescent sensor array

The broad class of explosives includes nitro aromatics as well as challenging aliphatic nitro-organics whose detection is important from counter-terrorism and national security perspectives.Here we report a turn-on fluorescent sensor array based on aggregation-induced emission(AIE)fluorophores as receptors.To achieve a good sensing system with fast response,good sensitivity and low detection limit,three receptors with abundant chemical diversities for target analytes were synthesized.The turn-on response of the individual receptor showed highly variable and cross-reactive analyte-dependent changes in fluorescence.The excellent ability to identify a variety of explosives,especially the challenging aliphatic nitro-organics(2,3-dimethyl-2,3-dinitrobutane(DMNB),1,3,5-trinitro-1,3,5-triazinane(RDX),cyclotetramethylene tetranitramine(HMX)and entaerythritol tetranitrate(PETN)),was demonstrated in qualitative and quantitative analyses with 100%accuracy.The fluorescence signal amplification in the presence of explosives allows for application of these receptors in a sensor microarray suitable for high-throughput screening.These results suggested that the cross-reactive sensor array based on AIE fluorophores could find a wide range of applications for sensing various analytes or complex mixtures.

Activating transcription factor 5 regulates lipid metabolism in adipocytes

Activating transcription factor 5(ATF5) is a member of the activating transcription factor/cA MP response element binding protein(ATF/CREB) family, and is highly expressed in liver and adipose tissue. Previous reports have shown that ATF5 promoted 3T3-L1 preadipocytes differentiation. In this study, we found that ATF5 was highly expressed in mature adipocytes, suggesting a potential role of ATF5 in mature adipocytes, which has not been reported previously. To understand the function of ATF5 in mature adipocytes, we knocked down the expression of ATF5 in 3T3-L1 mature adipocytes and observed decreased lipid droplets. Consistent with the in vitro experiment, the knockdown of ATF5 in white adipose tissue led to less adipose tissue and smaller adipocytes size. Further research revealed that the inhibition of ATF5 diminished the adipocytes size via the inhibition of fatty acid synthetase, stearyl coenzyme A desaturation enzyme 1, and the induction of carnitine palmitoyl transferase 1, one key enzyme of lipid metabolism. In addition, ATF5 knockdown in inguinal white adipose tissue improved whole body insulin sensitivity.Our work provides a new understanding of ATF5 function in mature adipocytes and a potential therapeutic target of diabetes.