广东省3岁及以上城市居民脂肪及脂肪酸摄入状况分析

目的 分析广东省城市居民的脂肪及脂肪酸的摄入水平与食物来源.方法 2017-2018年选取广东省5个城市,采用多阶段分层整群抽样方法抽取3岁及以上居民,运用非连续3 d 24 h回顾调查法收集调查对象膳食摄入信息.结果 广东省城市居民平均每日能量摄入量为1671.9 kcal,脂肪摄入为69.2 g,脂肪供能比为39....     

油凝胶替代动物脂肪在肉制品中应用的研究进展

动物脂肪对肉制品的多汁性以及风味起着重要作用,但其含有大量的饱和脂肪酸和胆固醇,过量摄入会对人体造成潜在的危害。然而,单纯地降低肉制品中的脂肪含量会对产品的品质产生负面影响。因此,如何降低肉制品中的脂肪含量并保持产品的品质已经成为肉类工业中亟待解决的问题。以植物油为主的油凝胶具有较好的脂肪酸组成,而且油凝胶具有与动物脂肪相似的性质,能够在一定程度上赋予肉制品润滑、醇厚的口感以达到替代肉制品中动物脂肪含量并保持最终产品的品质特性的目的。因此,本文全面综述了油凝胶的制备方法和形成机理,以及不同种类的油凝胶替代动物脂肪在肉制品中的应用情况,以期为生产新型健康的低饱和脂肪酸含量和低胆固醇含量的肉制品提供理论依据。     

肠道梭菌在机体能量过度摄入中的作用

肥胖与肠道菌群对能量的过度摄入有密切的关系。目前发现人体肠道中与肥胖有关的细菌主要有厚壁菌门和拟杆菌门细菌,其中梭菌属是厚壁菌门中非常重要而且数量庞大的一类菌。研究表明肠道梭菌属细菌代谢是导致机体能量摄入过度的主要原因之一。此外,肠道菌的多糖水解酶降解膳食纤维产生短链脂肪酸提供机体额外的能量,细菌脂多糖的吸收增多促进机体能量过度摄入,饥饿诱导脂肪因子的表达受到抑制时能量更容易以脂肪的形式蓄积,这些因素均与肥胖的形成有密切关系。但是目前对肠道梭菌在以下几个方面的作用仍未被阐明:1)梭菌是否是多糖水解酶的主要来源;2)多糖水解酶产生的短链脂肪酸对能量摄入的贡献;3)梭菌占优对细菌脂多糖的产生与吸收的影响;以及4)梭菌对FIAF表达的影响等。本文提出了可能的机制,为进一步的研究提供参考。     

脂肪替代物研究及生产的发展现状

脂肪是食品的重要组成部分,但高脂肪的摄入引起肥胖和某些癌症。摄入过多的饱和脂肪酸易引起血液胆固醇增高和冠状心血管疾病。目前,肥胖病人及相关疾病在逐年增加。因而,选用脂肪代用品很有必要。一、脂肪代用品１－蔗糖脂肪酸聚酯（Ｏｌｅｓｔｒａ）　蔗糖聚酯是蔗糖与６～８个长链脂肪酸酯化的产物,产品为Ｏｌｅｓｔｒａ（美国,ＴｈｅＰｒｏｃｔｅｒ＆Ｇａｍｂｌｅ公司生产）。由于Ｏｌｅｓｔｒａ通过消化道后没有被分解吸收,其又是脂溶性的,对消化道有一定潜在的影响,如腹痛、大便变软或腹泻、减少脂溶性维生素和一些营养物质的…     

肉品中脂肪检测技术研究进展

脂肪是食品中重要的营养成分,可供给能量和必需脂肪酸,可作为脂溶性维生素载体.肉品中脂肪含量与脂肪酸种类及其组成直接影响肉品的质量和风味.本文介绍动物油脂的相关概念,重点论述肉品中脂肪的提取与检测方法,以及气相色谱法、高效液相色谱法、薄层色谱法和红外光谱法在脂肪酸分析检测中的应用现状.     

高原地区食物中脂肪和脂肪酸的分析研究

对海拔２０００～４５００ｍ高原动植物中脂肪和脂肪酸值进行采样分析,反映生长在高原地区牛肉、羊肉、猪肉、鸡肉等动物不同部位脂肪和脂肪酸的含量,为人们对脂肪和脂肪酸的科学膳食和合理利用提供依据。     

肉制品低能量化的技术开发

肉制品低能量化的关键在于降低脂肪含量，同时保持其与传统全脂肉制品相似的风味和质构，通过基因控制或饲养方法的调整，有助于减少动物肉质固有的脂肪，调整其脂肪酸组成，使肉制品更健康化。通过物理方法除去配料中的脂肪，同时配合使用合适的脂肪替代品及其他配料，是降低肉制品能量的重要手段。     

低脂食品影响人体健康的最新进展

体内过剩的脂肪往往是诱发部分恶性疾病的重要因素,所以人们一直都在致力于开发低脂食品。但由于脂肪是食品能量的集中来源与必需脂肪酸的唯一来源,也是脂溶性维生素的载体,单纯减少对脂肪的摄入将对人体健康带来某些不利影响。因此,应根据各年龄段机体（特别是孕妇、乳母、婴儿、儿童和青少年等）对脂肪的不同需求,精心设计食品结构,做到既有效避免了过量脂肪可能造成的危害,又保证了机体对能量与营养素的摄入。     

吃油要讲究脂肪酸平衡

吃多少油?吃什么油?怎样选购和保管油?怎样用油才科学?这是大家都关心的问题。2004年我国人均食用植物油的消费量是13·5公斤,即人均月消费量为1公斤多。加上鸡鸭鱼肉的动物性脂肪的消费,人均月膳食脂肪(从食品中所摄入的总脂肪量)为2公斤左右。从我国人民的健康状况看,我认为人均月2公斤膳食脂肪已经满足人体需要了。我国有些地方普遍食油过多,这与心血管病等疾病发病率高是有关系的。此外,吃油时脂肪酸平衡的问题也是需要重视的。脂肪酸平衡是怎么一回事呢?油脂的学名叫“甘油三酯”,由甘油和脂肪酸组成。脂肪酸的种类很多(如根据饱和程度…     

日粮中脂肪的添加

通常认为只有肉用仔鸡的日粮和幼畜的代乳料中才添加脂肪，以满足其较高的能量需求。家畜日粮中不添加脂肪，家畜的脂肪可由饲料中的脂肪酸合成（而实际上，除必需脂肪酸外，家畜体组织的脂肪酸又可由碳水化合物或其在瘤胃发酵产生的醋酸盐来合成）。然而最近一段时间，越来越多的人对在生产家畜的日粮中添加脂肪产生兴趣。为此，本文就日粮中添加脂肪的重要性、添加脂肪对动物生产性能的影响以及其应注意的问题进行探讨。１　日粮中添加脂肪的重要性日粮添加脂肪的重要性概括如下：①要提高家畜生产潜力，就需要提高日粮的消化能含量；②饲…     

Effect of calcium on fatty acid bioaccessibility during in vitro digestion of Cheddar-type cheeses prepared with different milk fat fractions

Calcium plays an important role in intestinal lipid digestion by increasing the lipolysis rate, but also limits fatty acid bioaccessibility by producing insoluble Ca soaps with long-chain fatty acids at intestinal pH conditions. The aim of this study was to better understand the effect of Ca on the bioaccessibility of milk fat from Cheddar-type cheeses. Three anhydrous milk fats (AMF) with different fatty acid profiles (olein, stearin, or control AMF) were used to prepare Cheddar-type cheeses, which were then enriched or not with Ca using CaCl₂ during the salting step. The cheeses were digested in vitro, and their disintegration and lipolysis rates were monitored during the process. At the end of digestion, lipids were extracted under neutral and acidic pH conditions to compare free fatty acids under intestinal conditions in relation to total fatty acids released during the digestion process. The cheeses prepared with the stearin (the AMF with the highest ratio of long-chain fatty acids) were more resistant to disintegration than the other cheeses, owing to the high melting temperature of that AMF. The Ca-enriched cheeses had faster lipolysis rates than the regular Ca cheeses. Chromatographic analysis of the digestion products showed that Ca interacted with long-chain fatty acids, producing Ca soaps, whereas no interaction with shorter fatty acids was detected. Although higher Ca levels resulted in faster lipolysis rates, driven by the depletion of reaction products as Ca soaps, such insoluble compounds are expected to reduce the bioavailability of fatty acids by hindering their absorption. These effects on lipid digestion and absorption are of interest for the design of food matrices for the controlled release of fat-soluble nutrients or bioactive molecules.     

Production responses of dairy cows when fed supplemental fat in low- and high-forage diets

Intake of net energy for lactation (NE_L) is often the limiting factor for milk production and is affected by stage of lactation and dietary concentrations of forage and fat. Because of the mechanisms involved, interactions are likely between those 2 diet components and stage of lactation. We conducted an experiment with 72 Holstein cows starting at 21 and ending at 126 d in milk (DIM). Cows were fed diets (dry matter basis) with 40 or 60% forage (67% corn silage, 33% alfalfa silage) each with 0 or 2.25% added saturated free fatty acids. The high- and low-forage diets contained 25 and 17% forage neutral detergent fiber and 30 and 33% total neutral detergent fiber, respectively; the low-forage diets contained several byproducts. Diets with and without fat contained approximately 5.2 and 3.2% long-chain fatty acids, respectively. Feeding fat or low-forage diets increased NE_L intake, but no interaction was observed. The increase in NE_L intake by cows fed low-forage diets was caused by increased dry matter intake, and the increase in NE_L intake by cows fed fat was caused by increased energy density of the diet. Interactions between fat and forage were observed for energy utilization. When high-forage diets were supplemented with fat, the increased NE_L intake went toward body energy reserves as measured by higher body condition scores with no change in milk yield. However, when low-forage diets were supplemented with fat, milk yield increased (2.6 kg/d) with no change in body condition. The differential partitioning of NE_L may have been caused by nutrients other than NE_L limiting milk production in cows fed the high-forage diets. With low-forage diets, intake of other nutrients was greater (i.e., greater dry matter intake). At 35 DIM, dietary treatments had little effect on milk fatty acids composition but in later lactation (125 DIM), feeding supplemental fatty acids or feeding low-forage diets increased long-chain fatty acids and decreased short-chain fatty acids. However, treatment did not have marked effects on concentrations of total fat or protein in milk. The amount of forage in a diet influences cow responses to supplemental fat and should be considered when diets are formulated.     

Changes in fermentation and animal performance during recovery from classical diet-induced milk fat depression using corn with differing rates of starch degradability

Diet-induced milk fat depression (MFD) is a multifactorial disorder that can be triggered by a variety of conditions. Feeding high amounts of starch and unsaturated fatty acids has been shown to reduce milk fat yield and composition, as well as alter ruminal biohydrogenation patterns. However, little is known about how starch degradability in the rumen influences recovery from diet-induced MFD and if production of milk fat–inhibiting isomers will persist following an episode of MFD. The objective of this study was to evaluate production performance and ruminal fermentation in cows recovering from MFD when corn with a low or high starch degradability is fed. Six ruminally fistulated Holstein cows were used in a crossover design with 2 periods. During each period, MFD was induced for 10 d by feeding a diet with low fiber, high starch, and high unsaturated fatty acid. The polyunsaturated fatty acid concentration of the diet during the induction phase was modified primarily through inclusion of soybean oil. Following induction, cows were switched to either a high degradable starch recovery diet (HDS) or a low degradable starch recovery diet (LDS) for 18 d. The 7-h starch degradability was 66.5% for LDS and 87.8% for HDS. Milk was collected every 3 d for component and fatty acid analysis. On d 0, 4, 7, 10, 16, 22, and 28 of each period, ruminal pH and rumen fluid were collected every 2 h. Milk fat yield and composition was reduced during MFD induction and progressively increased by day in both HDS and LDS during recovery. Dry matter intake was similar among treatments and increased steadily over time during recovery. Preformed fatty acids were greater for HDS-fed animals, and de novo fatty acid in milk fat was greater for LDS-fed animals. Milk trans-10 C18:1 tended to be greater for HDS, and trans-10,cis-12 conjugated linoleic acid was significantly greater for HDS. cis-9,trans-11 conjugated linoleic acid was not affected by starch degradability during recovery. Total volatile fatty acids, butyrate, and valerate tended to differ or differed with recovery treatment, but ruminal pH and ammonia concentration were unaffected. The HDS diet responded similarly to the LDS diet during recovery with regard to milk fat percentage, but milk and fat yield tended to consistently be lower in HDS. When considering approaches to ameliorate diet-induced MFD, the degradability of the starch within rations should be evaluated. Although animal performance was similar, some trans fatty acid isomers were persistent in the milk through the recovery phase with HDS-fed animals, suggesting that milk fat synthesis might be potentially inhibited and biohydrogenation pathways modified in the rumen following an episode of MFD.     

Effects of fatty acid supplements on milk yield and energy balance of lactating dairy cows

Saturated and unsaturated fatty acid supplements (FS) were evaluated for effects on yield of milk and milk components, concentration of milk components including milk fatty acid profile, and energy balance. Eight ruminally and duodenally cannulated cows and 8 noncannulated cows were used in a replicated 4 × 4 Latin square design experiment with 21-d periods. Treatments were control and a linear substitution of 2.5% fatty acids from saturated FS (SAT; prilled, hydrogenated free fatty acids) for partially unsaturated FS (UNS; calcium soaps of long-chain fatty acids). The SAT treatment did not change milk fat concentration, but UNS linearly decreased milk fat in cannulated cows and tended to decrease milk fat in noncannulated cows compared with control. Milk fat depression with UNS corresponded to increased concentrations of trans-10, cis-12 conjugated linoleic acid and trans C18:1 fatty acids in milk. Milk fat profile was similar for SAT and control, but UNS decreased concentration of short- and medium-chain FA. Digestible energy intake tended to decrease linearly with increasing unsaturated FS in cannulated and noncannulated cows. Increasing unsaturated FS linearly increased empty body weight and net energy gain in cannulated cows, whereas increasing saturated FS linearly increased plasma insulin. Efficiency of conversion of digestible energy to milk tended to decrease linearly with increasing unsaturated FS for cannulated cows only. Addition of SAT provided little benefit to production and energy balance, whereas UNS decreased energy intake and milk energy yield.     

Effects of trans-10, cis-12 conjugated linoleic acid on ovine milk fat synthesis and cheese properties

Trans-10, cis-12 conjugated linoleic acid (CLA) reduces milk fat synthesis in sheep in a manner similar to that seen in dairy cows, but its effects on cheese yield and flavor are unknown. Additionally, when dietary energy supply is restricted, CLA can increase milk and milk protein yield, which may alter cheese yield and eating quality. The objectives of the study were to examine the effects of supplementing ewe diets with a rumen-protected source of CLA at a high and low dietary energy intake on milk fat and protein synthesis and on cheese yield and eating quality. Sixteen multiparous ewes were randomly allocated to 1 of 4 dietary treatments: a high (6.7 Mcal of metabolizable energy/d) or low (5.0 Mcal of metabolizable energy/d) feeding level that was either unsupplemented or supplemented with 25 g/d of a lipid-encapsulated CLA (to provide 2.4 g/d of CLA) in each of 4 periods of 21 d duration in a 4 × 4 Latin square design. There was no effect of treatment on milk yield (g/d), but milk fat percentage and milk fat yield were reduced by 23 and 20%, respectively, in ewes supplemented with CLA. Milk fatty acid concentration (g/100 g) of chain length <C₁₆ was decreased and >C₁₆ was increased in milk and cheese following CLA supplementation, whereas decreasing the feeding level increased fatty acids ≥C₁₆. Milk fat contents of CLA were 0.01 and 0.12 g/100 g of fatty acids for the unsupplemented and CLA-supplemented treatments, respectively, whereas cis-9, trans-11 CLA was unaffected by CLA supplementation. There was no main effect of treatment on cheese yield, which was 0.11 ± 0.001 kg of cheese/kg of milk, but cheese yield was highest, at 0.12 ± 0.001 kg/kg, when made from milk of ewes fed the high feeding level + unsupplemented treatment. Cheese made from the milk of ewes supplemented with CLA, compared with the unsupplemented diet, was rated (scale 0 to 10) higher in the creaminess (2.1 vs. 1.4; SEM 0.15) and less oily (0.8 vs. 1.3; SEM 0.17) attributes, and was preferred overall (4.5 vs. 3.9; SEM 0.21). Cheese produced from sheep on the high vs. low feed level was rated less yellow (2.8 vs. 4.2; SEM 0.11), less salty (1.9 vs. 2.3; SEM 0.15), and more sour (1.5 vs. 1.1; SEM 0.13). We concluded that the effect of feeding level on animal performance and cheese characteristics was small, whereas supplementing the diets of ewes with a ruminally protected CLA source reduced milk fat yield, did not affect cheese yield, and beneficially altered the flavor characteristics of the cheese.     

The value of different fat supplements as sources of digestible energy for lactating dairy cows

The effects of fat supplements that differed in fatty acid composition (chain length and degree of saturation) and chemical form (free fatty acids, Ca salts of fatty acids, and triacylglyceride) on digestible energy (DE) concentration of the diet and DE intake by lactating cows were measured. Holstein cows were fed a control diet [2.9% of dry matter (DM) as long-chain fatty acids] or 1 of 3 diets with 3% added fatty acids (that mainly replaced starch). The 3 fat supplements were (1) mostly saturated (C18:0) free fatty acids (SFA), (2) Ca-salts of fatty acids (CaFA), and (3) triacylglyceride high in C16:0 fatty acids (TAG). Cows fed CaFA (22.8 kg/d) consumed less DM than cows fed the control (23.6 kg/d) and TAG (23.8 kg/d) diets but similar to cows fed SFA (23.2 kg/d). Cows fed fat produced more fat-corrected milk than cows fed the control diet (38.2 vs. 41.1 kg/d), mostly because of increased milk fat percentage. No differences in yields of milk or milk components were observed among the fat-supplemented diets. Digestibility of DM, energy, carbohydrate fractions, and protein did not differ between diets. Digestibility of long-chain fatty acids was greatest for the CaFA diet (76.3%), intermediate for the control and SFA diets (70.3%), and least for the TAG diet (63.3%). Fat-supplemented diets had more DE (2.93 Mcal/kg) than the control diet (2.83 Mcal/kg), and DE intake by cows fed supplemented diets was 1.6 Mcal/d greater than by cows fed the control, but no differences were observed among the supplements. Because the inclusion rate of supplemental fats is typically low, large differences in fatty acid digestibility may not translate into altered DE intake because of small differences in DM intake or digestibility of other nutrients.     

Influence of dietary fat on pork eating quality

This study compared the influence of dietary fat sources on meat quality, fatty acid composition and sensory attributes in pork. The experiment was conducted with 43 entire male pigs (Pietrain×(Landrace×Large White)) which were fed a basal diet without added fat (control diet) or supplemented with different sources of fat: animal fat (1%, AF1; 3%, AF3), soyabean oil (1%, SBO1) and calcium soaps of palm oil (1%, CaSPO1). Dietary fat supplementation did not significantly affect ultimate pH, colour, Warner-Bratzler shear force values, sensory attributes or SFA. Pigs fed SBO1 had the lowest proportion of MUFA and the highest of PUFA. In conclusion, these dietary fat sources could be recommended for inclusion in diets, at these levels, with no detrimental effect on eating quality. Despite finding no significant differences, the PCA afforded a comprehensive view of the predominating attributes of pork from animals fed the different fats.     

Effect of fatty acids or calcium soaps on rumen and total nutrient digestibility of dairy rations

Two trials ascertained whether feeding fatty acids as preformed calcium soaps would permit normal digestibility of fiber without reducing availabilities of fatty acids or energy. Six diets contained no added fat (control) or the equivalent of 4.5% added fatty acids as tallow or soy fatty acids, tallow or soy calcium soaps, or tallow combined with the nonnutritive carrier verxite. Six cows were fed each diet in trial 1 to ascertain digestibilities of total nutrients, whereas control, tallow fatty acid, and tallow soap diets were fed to steers with duodenal cannulae in trial 2 to evaluate effects of fat source on rumen fermentation. Digestibility of total fiber in trial 1 was reduced 13% by tallow fatty acids. In trial 2, tallow fatty acids markedly reduced digestibility of dry matter and fiber in the rumen. Diets supplemented with tallow calcium soaps had normal digestibilities of fiber in the rumen and totally, but digestibility of fatty acids was reduced 6% and digestibility of energy reduced 3% compared to feeding tallow fatty acids. Efficiency of synthesis of microbial protein was 39% higher for tallow fatty acids than for control. Feeding tallow verxite also permitted normal digestibility of fiber in trial 1 but caused reduced availabilities of fatty acids and energy.(ABSTRACT TRUNCATED AT 250 WORDS)