【作者】 扈晓杰；

【导师】 李铎；

【作者基本信息】 浙江大学 ， 食品科学， 2013， 博士

【摘要】 肥胖已经在全球广泛盛行,威胁着全人类的健康。肥胖与许多慢性疾病密切相关,如糖尿病,心血管疾病,消化系统疾病,呼吸道疾病以及各种癌症。岩藻黄素(fucoxanthin)是海藻中特殊类胡萝卜素的重要种类之一,含有丙二烯和环氧烷的特殊结构,这种特殊结构决定了其具有抗肥胖、调节血糖、抗肿瘤、清除自由基、抗氧化、抗血管新生等多种生理活性。共轭亚油酸(conjugated linoleic acids, CLA)是必需脂肪酸-亚油酸(linoleic acid, LA)的异构体,是天然存在的十八碳二烯酸,含有共轭双键,属于多不饱和脂肪酸。近年来研究证明,CLA有多种生理活性,包括预防动脉粥样硬化,促进动物生长,提高机体免疫力,减少脂肪沉积和影响脂肪代谢、减少甘油三酯含量,抗肿瘤,改善Ⅱ型糖尿病等。豆渣是加工豆腐、豆乳等豆制品的副产品,其中含有丰富的膳食纤维,产热低,并含有钙、磷、铁、维生素等营养成分,对肥胖症、糖尿病、心血管疾病等具有一定的防治作用。膳食纤维是食品营养中的第七大营养元素,对人体健康至关重要。但是目前我国人均膳食纤维摄入量较低,而豆渣富含膳食纤维,其含量达50%～70%,却由于豆渣直接食用,口感粗糙,难以下咽,所以限制了豆渣在食品中的应用。目前我国年产约2000万吨湿豆渣,其中大部分只用作饲料。首先通过对SD大鼠的饮食干预,研究了岩藻黄素及岩藻黄素和共轭亚油酸组合对大鼠体重、脂肪湿重、血脂和组织病理等的影响,同时测定了脂肪组织中脂联素,瘦素,脂质生成,分解和转运相关的酶,UCP2等基因的表达。研究发现,岩藻黄素可以显著地降低体重,脂肪湿重和肝重,改善高脂引起的脂肪肝变性,降低游离脂肪酸在血清中的含量,同时,岩藻黄素还具有提高抵抗素,脂肪甘油三酯脂肪酶和肉碱棕榈酰转移酶1A等基因表达的作用。岩藻黄素和共轭亚油酸能够促进脂质分解代谢以及脂肪酸转运基因表达的上调,同时促进脂肪合成酶基因的下调,加速了脂肪酸的p氧化和TG的水解,抑制脂质生成和成熟脂肪细胞的分化,从而起到降低肥胖大鼠体重的作用。这为今后藻类中岩藻黄素的食(药)用开发利用和营养评价以及共轭亚油酸的进一步加工利用提供了一定的理论研究基础和科学依据。其次,研究将豆渣粉添加到饼干中,用特制的豆渣饼干对超重和肥胖者进行随机对照干预试验,探究豆渣中膳食纤维降低体重,改善血脂和体脂的作用及其机制。试验结果表明,12周后,食用豆渣膳食纤维的试验者体重,BMI和血清LDL-C水平显著降低。同时,豆渣组试验者的体重、BMI、腰围和舒张压,血清TC、LDL-C、血糖水平、体脂和躯干脂肪含量亦均显著低于干预前。膳食纤维主要是能够促进过饱状态,抑制食欲,从而减少食物摄入来降低体重和体脂。膳食纤维还有可能通过胆汁酸的排泄,继而促进胆固醇向胆汁酸的转变从而引起血清中胆固醇水平降低。这些结果说明,豆渣膳食纤维对超重和肥胖者的体重、血压、腰围、血清脂质水平和体脂具有明显的改善作用。更多还原

【Abstract】 The prevalence of obesity is increasing all over the world, posing a threat to human health. Obesity has close correlation with many chronic diseases, such as diabetes mellitus, cardiovascular diseases, digestive system diseases, respiratory tract diseases and various cancers.Fucoxanthin (Fc) is one of the important marine carotenoids that is characterized by a unique structure including an allenic bond and5,6-monoepoxide, exerting many benefits, such as antiobesity, modulation of glucose, anticancer, antioxidant, angiogenesis, and radical free radical scavenging. Conjugated linoleic acid (CLA), a natural octadecadienoic acid containing conjugated double bond, refers to a group of polyunsaturated fatty acids that exists as the isomer of linoleic acid (LA). CLA possess many beneficial physiologic effects including reducing the development of atherosclerosis, enhancing growth, improving immunity of organisms, decreasing accumulation of body fat, reducing the concentration of triglyceride, anticancer, and improving type II diabetes.The soybean dregs are the byproducts of tofu and soymilk manufacturing, rich in dietary fiber and low-caloric, besides containing nutritional components, such as calcium, phosphorus, ferrum and vitamins, which is beneficial for obesity, diabetes, and cardiovascular diseases. The dietary fiber is called the seventh nutritional element which has significant function to human health. Nowadays, the intake of dietary fiber in China is relatively low, though dietary fiber is rich in soybean dregs (approximately50%-70%of total masses), the application in food industry of soybean dregs is restricted due to the rough taste. The production of soybean dregs is approximately20million tons per year, most of which are used as feed. The part of research the powder of soybean dregs supplemented with the biscuits, which are used to conduct the randomized controlled trial on overweight and obese subjects. The aim of this part was to explore the effects of dietary fiber in soybean dregs on weight loss, fat loss and the improvement of lipid profile.First of all, Fc and Fc plus CLA supplemented in the diet were prepared for Sprague Dawley (SD) rats. Body weight, weight of white fat tissue and liver, histological observation of liver and white adipose tiuuse (WAT), serum lipid profile and the mRNA expression of Adi, leptin, enzymes of lipogenesis, transportation and lipolysis, and UCP2in WAT of SD rats were determined. The results showed that body weight, weight of white fat tissue and liver, and accumulation of hepatic lipid droplets, were significantly decreased by Fc and Fc+CLA. In addition, the mRNA expression of adiponectin, adipose triacylglycerol lipase, carnitine palmitoyltransferase1A was remarkably up-regulated in Fc and Fc+CLA groups. Fc and CLA up-regulated the expression of lipolysis genes, down-regulated the expression of lipogenesis genes, accelerate β-oxidation and the hydrolysis of TG, inhibited the lipogenesis and differentiation of mature adipocytes, thus exerting the effects on antiobesity of high-fat diet-induced rats. In summary, Fc and CLA were beneficial for the antiobesity though exhibiting different mechanisms. The present research provide theoretical and scientific basis for the exploitation of nutraceutical or medicinal food and nutritional evaluation.In the next part, thirty nine overweight and obese college adults (aged19-39y, BMI=23-30kg/m2) were randomly assigned to consume control biscuits or biscuits supplemented with soy fiber for12wks (approximately100g/d). There were significant differences in changes on body weight, body mass index (BMI) and low density lipoprotein cholesterol (LDL-C) between the two groups after12wk intervention. Body weight, body mass index (BMI), waist circumference, diastolic blood pressure, serum levels of total cholesterol, low density lipoprotein cholesterol, glucose, body fat and trunk fat of participants in soy fiber group were decreased significantly over the study period compared with the baseline. Soy fibers may help prevent weight gain by promoting satiety, inhibiting appetite and decreasing spontaneous food intake. Soy fiber might accelerate fecal bile acid excretion and the subsequent increase in conversion of cholesterol to bile acid, finally resulting in a decrease in the serum cholesterol levels. Soy fiber had favorable effects on body weight, blood pressure, fasting lipid levels and body fat in overweight and obese adults.更多还原