大豆的几种预处理工艺

通过对大豆传统的软化、轧胚、烘胚、浸出工艺；粉碎、干式挤压膨化、浸出工艺；预热软化、轧胚、膨化、浸出工艺的实践和分析，得出“采用预热软化、轧胚、膨化、浸出工艺既能降低高水分大豆的入浸水分，又能降低生产成本，提高出油率，具有一定的经济优势”的结论。     

油料挤压膨化机的正确选用

目前 ,我国大多数油脂厂均采用浸出法制油。油脂的生产过程一般包括油料预处理、浸出、精炼等工序。其中 ,油料预处理在整个工艺中具有十分重要地位 ,对油脂的品质、提取率、生产效率等影响较大。传统的油料预处理方法由于对轧胚工艺要求高、浸出效率低逐渐被新的挤压膨化预处理技术所代替。早在 2 0世纪 60年代 ,美国、巴西已开始采用挤压膨化预处理工艺浸出制油 ,由于油料经挤压膨化后 ,容重增大 ,并呈微孔状 ,其渗透性被大大提高 ,浸出溶剂的通过料层速度也大大加快 ,由此 ,浸出器的生产能力被显著提高 ,而且大大降低了浸出溶剂回收能耗。所以 ,随着人们对油料挤压膨化技术在油脂生产中应用优势的认识 ,近年来挤压膨化技术被广泛地应用于油脂和饲料的生产 ,为此 ,本文就油料挤压膨化机合理选用及其正确使用等进行论述 ,为厂家正确应用油料挤压膨化机提供指导性意见 ,使油料膨化技术在生产中真正起到作用 ,达到增产、降耗、提高浸出效率之目的。     

玉米胚挤压膨化预处理浸油微观机理研究

应用植物显微技术,通过石蜡切片观察,对用于浸油的玉米胚挤压膨化预处理工艺的微观机理进行了探讨,结果表明,挤压膨化物比轧坯和预轧样浸提时间缩短、残油率低,主要是因为挤压膨化后油料细胞壁破坏较彻底,油脂有明显的聚集现象,以及水分瞬间汽化后形成大量的毛细孔道所造成的.     

油料挤压膨化机的正确选用

目前，我国大多数油脂厂均采用浸出法制油。油脂的生产过程一般包括油料预处理、浸出、精炼等工序。其中，油料预处理在整个工艺中具有十分重要地位，对油脂的品质、提取率、生产效率等影响较大。传统的油料预处理方法由于对轧胚工艺要求高、浸出效率低逐渐被新的挤压膨化预处理技术所代替。早在20世纪60年代，美国、巴西已开始采用挤压膨化预处理工艺浸出制油，由于油料经挤压膨化后，容重增大，并呈微孔状，其渗透性被大大提高，浸出溶剂的通过料层速度也大大加快，由此，浸出器的生产能力被显著提高，而且大大降低了浸出溶剂回收能耗。所以，随着人们对油料挤压膨化技术在油脂生产中应用优势的认识，近年来挤压膨化技术被广泛地应用于油脂和饲料的生产，为此，本文就油料挤压膨化机合理选用及其正确使用等进行论述，为厂家正确应用油料挤压膨化机提供指导性意见，使油料膨化技术在生产中真正起到作用，达到增产、降耗、提高浸出效率之目的。     

挤压膨化技术在油脂工业上的应用

本文叙述了何谓挤压膨化技术,油料经过挤压膨化处理将发生的作用,大豆膨化浸出工艺中试的情况,以及高合油油料的挤压膨化预处理。     

挤压膨化技术在油脂工业上的应用

本叙述了何谓挤压膨化技术,油料经过挤压膨化处理将发生的应用,大豆化浸出工艺中试的情况,以及高含油油料的挤压膨化预处理。     

对大豆几种预处理工艺的实践和分析

通过对大豆传统的软化、轧坯、烘坯、浸出工艺；粉碎，干式挤压膨化浸出工艺；预热软化、轧坯、膨化、浸出工艺的实践和分析、比较，得出结论：采用预热软化、轧坯、膨化工艺既能降低高水分大豆的入浸水分，又能降低生产成本，提高出油率，具有一定的经济优势     

玉米胚挤压膨化预处理浸油过程中糊底问题研究

探讨用于浸油的玉米胚挤压膨化预处理过程中的挤压系统参数对膨化物剪切强度和浸出过程中糊底程度的影响规律.研究玉米胚挤压膨化物的剪切强度、粉末度与浸出过程中糊底问题的相关性,结果表明:只要挤压膨化系统参数选择合适,可以在获得较低残油率的情况下较好的解决浸出过程中的糊底问题.     

棉籽膨化制油技术

油料在浸出前进行挤压膨化预处理，是一种新兴的适合于多种油料的生产工艺。６０年代美国安迪生公司率先将这一技术应用于米糠浸出前的预处理。目前美国约有６０％的大豆和５０％的棉籽采用挤压膨化预处理。九十年代初，我国已开始研究油料膨化浸出取油工艺，并应用于米糠...     

棉籽制油过程中膨化技术的应用

棉籽是我国的主要油料和蛋白质资源之一，年产量约750吨左右，居世界首位。我国对棉籽加工多采用预榨浸出法，棉仁直接浸出工艺，采用膨化浸出法也有不少。膨化预处理技术作为一种新兴技术，现已应用于大豆、米糠、菜籽等油料的膨化浸出工艺。近几年，挤压膨化技术也不断应用于棉籽制油工艺中，棉仁膨化浸出工艺大有取代棉籽预榨浸出和棉仁生坯一次浸出工艺之势。油料在浸出前进行挤压膨化预处理，是一种新兴的适合于多种油料的生产工艺。本文仅对膨化技术在棉籽制油工艺中的应用……     

Conjugated linoleic acid content of milk and cheese from cows fed extruded oilseeds

Extruded oilseeds were fed to 24 dairy cows to study the influence on the conjugated linoleic acid content of milk and cheese. Cows were fed one of three diets that contained forage and grain in a ratio of 47:53. A control diet containing 13.5% soybean meal was compared with diets containing 12% full fat extruded soybeans or 12% full fat extruded cottonseed. The control, extruded soybean, and extruded cottonseed diets contained 2.73, 4.89, and 4.56% fatty acids, respectively. Measurements were made during the last 5 wk of the 8-wk experiment. The DM intakes and 3.5% fat-corrected milk yields were higher for cows fed the extruded soybean and extruded cottonseed diets than for cows fed the control diet. A tendency for lower fat and protein contents in the milk of cows fed the extruded soybean and extruded cottonseed diets was detected. Most of the C18 fatty acids were increased in the milk and cheese when extruded soybeans and cottonseeds were fed. The conjugated linoleic acid content in milk and cheese increased a mean of 109% when full fat extruded soybeans were fed and increased 77% when cottonseeds were fed compared with the conjugated linoleic acid content when the control diet was fed. Processing the milk into cheese did not alter the conjugated linoleic acid content. The conjugated linoleic acid content of milk and cheese can be increased by the inclusion of full fat extruded soybeans and full fat extruded cottonseeds in the diets of dairy cows.     

Feeding fish meal and extruded soybeans enhances the conjugated linoleic acid (CLA) content of milk

Twelve multiparous Holstein cows averaging 65 (33 to 122) DIM were used in a 4 x 4 Latin square for 4-wk periods to determine whether feeding fish oil as fish meal would stimulate increased amounts of milk conjugated linoleic acid (cis-9, trans-11 C18:2; CLA) and transvaccenic acid (trans-11 C18:1; TVA) when the cows were fed extruded soybeans to supply additional linoleic acid. Treatment diets were 1) control; 2) 0.5% fish oil from fish meal; 3) 2.5% soybean oil from extruded soybeans; and 4) 0.5% fish oil from fish meal and 2% soybean oil from extruded soybeans. Diets were formulated to contain 18% crude protein and were composed (dry basis) of 50% concentrate mix, 25% corn silage, and 25% alfalfa hay. Intake of DM was not affected by diet. Milk production was increased by diets 2, 3, and 4 compared with diet 1 (control). Milk fat and milk protein percentages decreased with diets 3 and 4. Milk fat yield was not affected by treatments, but yield of milk protein was increased with supplemental fish meal and extruded soybeans or their blend. When diets 2, 3, or 4 were fed, concentrations of cis-9, trans-11 CLA in milk fat increased by 0.4-, 1.4-, and 3.2-fold, and TVA concentrations in milk fat increased by 0.4-, 1.8-, and 3.5-fold compared with the control milk fat. Increases in TVA and cis-9, trans-11 CLA were 91 to 109% greater when a blend of fish meal and extruded soybeans was fed than the additive effect of fish meal and extruded soybeans. This suggested that fish oil increased the production of CLA and TVA from other dietary sources of linoleic acid such as extruded soybeans.     

The effect of nonstructural carbohydrate and addition of full fat extruded soybeans on the concentration of conjugated linoleic acid in the milk fat of dairy cows

Conjugated linoleic acid (CLA), a naturally occurring anticarcinogen found in dairy products, is a byproduct of incomplete ruminal biohydrogenation of unsaturated fatty acids. Our objective was to determine the effect of nonstructural carbohydrate sources, addition of full fat extruded soybeans as a source of unsaturated fatty acids, and possible interactions on the milk fat content of CLA. Cows (n = 20) were assigned to a 4 x 4 Latin square involving two sources of nonstructural carbohydrate, high starch (corn) or high pectin (citrus pulp), with or without addition of extruded soybeans. Milk yield was not affected by nonstructural carbohydrate source, but milk production was increased by 7.8 to 10.5% with dietary additions of extruded soybeans. Milk fat content did not differ between treatments, but fatty acid composition was affected. Cows fed extruded soybean diets had reduced concentrations of C8 to C16 fatty acids and increased concentrations of octadecenoic acids. Diets with extruded soybeans also resulted in more than a doubling in milk fat concentration and yield of CLA. Nonstructural carbohydrate source had only minor effects on CLA, and there was no interaction with extruded soybeans. Milk fat content of trans-C18:1 and CLA were closely related (r2 = 0.77). However, variation among cows was about threefold for each of the diets and rank order of individual cows differed among diets. Overall, we demonstrated that diet modification can be used to alter CLA content of milk fat, but there was substantial individual cow variation for all diets.     

Effects of feeding lactating dairy cows diets containing extruded soybeans and calcium salts of long-chain fatty acids.

Four multiparous Holstein cows averaging 36 DIM and fitted with ruminal cannulas were utilized in a 4 x 4 Latin square design to investigate the effects of feeding extruded whole soybeans and Ca salts of long-chain fatty acids. Treatments were diets containing 1) no added fat, 2) 16% extruded whole soybeans, 3) 16% extruded whole soybeans and 3% Ca salts of long-chain fatty acids, and 4) 16% extruded whole soybeans and 6% Ca salts of long-chain fatty acids. Cows were fed for ad libitum intake a diet of alfalfa haylage, corn silage, and concentrate (35:15:50, DM basis). Intakes of DM and energy and production of milk, 4% FCM, fat, CP, and SNF were decreased by feeding extruded whole soybeans and 6% Ca salts of long-chain fatty acids, but differences were small among the other treatments. The weight percentages and yields of C18:0, C18:1, and C18:2 in milk were increased, and most shorter chain fatty acids were decreased, by feeding supplemental fat. Digestibilities of DM, OM, ADF, soluble residue, total C18 fatty acids, and total fatty acids were decreased, but digestibility of hemicellulose was increased by feeding supplemental fat. The largest decrease in digestibilities of most dietary constituents and in energy and N utilization occurred when 16% extruded whole soybeans plus 6% Ca salts of long-chain fatty acids were fed to the cows. Calcium salts of long-chain fatty acids can supply up to 3% of the dietary DM in diets containing 16% extruded whole soybeans without having deleterious effects on most variables measured in this experiment.     

Fish oil and extruded soybeans fed in combination increase conjugated linoleic acids in milk of dairy cows more than when fed separately

Eight multiparous Holstein and four multiparous Brown Swiss (78 +/- 43 DIM) cows were used in a 4 x 4 Latin square with 28-d periods to evaluate if feeding fish oil with a source of linoleic acid (extruded soybeans) would stimulate additional amounts of conjugated linoleic acid in milk. Four treatments consisted of a control diet with a 50:50 ratio of forage to concentrate (DM basis), a control diet with 2% added fat from either menhaden fish oil or extruded soybeans, or a combination of fish oil and extruded soybeans each adding 1% fat. DM intake (24.3, 21.6, 24.5, and 22.5 kg/d, for control, fish oil, extruded soybeans, and combination diets, respectively), milk production (32.1, 29.1,34.6, and 31.1 kg/d), and milk fat content (3.51, 2.79, 3.27, and 3.14%) were lower for cows that consumed either fish oil-containing diet, especially the 2% fish oil diet. The proportion of n-3 fatty acids in milk fat increased similarly among all three fat-supplemented diets. Concentrations of transvaccenic acid (1.00, 4.16, 2.17, and 3.51 g/100 g of fatty acids) and cis-9, trans-11 conjugated linoleic acid (0.60, 2.03, 1.16, and 1.82 g/100 g of fatty acids) in milk fat increased more with fish oil than with extruded soybeans. When fed the combination diet, these fatty acids were approximately 50% higher than expected for Holsteins, whereas concentrations were similar for Brown Swiss compared with feeding each fat source separately. These data indicated that fish oil modifies ruminal or systemic functions, stimulating increased conversion of linoleic acid into transvaccenic and conjugated linoleic acids.     

Composition and flavor of milk and butter from cows fed fish oil, extruded soybeans, or their combination.

Milk was collected from eight multiparous Holstein and four multiparous Brown Swiss cows that were distributed into four groups and arranged in a randomized complete block design with four 4-wk periods. The four treatments included a control diet of a 50:50 ratio of forage-to-concentrate; a fish oil diet of the control diet with 2% (on dry matter basis) added fat from menhaden fish oil; a fish oil with extruded soybean diet of the control diet with 1% (on dry matter basis) added fat from menhaden fish oil and 1% (on dry matter basis) added fat from extruded soybeans; and an extruded soybean diet of the control diet with 2% (on dry matter basis) added fat from extruded soybeans. Milk from cows fed control, fish oil, fish oil with extruded soybean, and extruded soybean diets contained 3.31, 2.58, 2.94, and 3.47% fat, respectively. Concentrations of conjugated linoleic acid in milk were highest in the fish oil (2.30 g/100 g of fatty acids) and fish oil with extruded soybean (2.17 g/100 g of fatty acids) diets compared with the control (0.56 g/100 g fatty acids) diet. Milk, cream, butter, and buttermilk from the fish oil, fish oil with extruded soybean, and extruded soybean diets had higher concentrations of transvaccenic acid and unsaturated fatty acids compared with the controls. Butter made from the extruded soybean diet was softest compared with all treatments. An experienced sensory panel found no flavor differences in milks or butters.     

Fatty acid profiles of milk and rumen digesta from cows fed fish oil,extruded soybeans or their blend

Four fistulated primiparous cows (two Holstein and two Brown Swiss) averaging 102 DIM were used in a 4 x 4 Latin square with 3-wk periods to determine the effect of feeding fish oil, extruded soybeans, or their combination on fatty acid profiles of milk and rumen digesta. Experimental diets consisted of: 1) control diet; 2) a diet with 2% (DM basis) added fat from menhaden fish oil; 3) a diet with 2% added fat from extruded soybeans; and 4) a diet with 1% added fat from fish oil and 1% fat from extruded soybeans. All diets consisted of 25% corn silage, 25% alfalfa hay, and 50% concentrate. Milk yields (28.6, 29.7, 29.2, and 28.1 kg/d for control, fish oil, extruded soybeans, and combination diets, respectively) were similar for all fat supplements and control. Milk fat and protein percentages (3.49, 3.08; 3.25, 2.96; 3.47, 3.01; 3.48, 2.99 for diets 1, 2, 3, and 4, respectively) were not affected by fat supplements compared with control. Dry matter intake (23.0, 21.6, 22.7, and 21.6 kg/d) was reduced when diets containing fish oil were fed. Concentrations of conjugated linoleic acid [CLA; cis-9, trans-11 CLA, 0.40, 0.88, 0.87, and 0.80 g/100 g fatty acids (FA)] and transvaccenic acid (TVA, 1.02, 2.34, 2.41, and 2.06 g/100 g of FA) were increased in milk fat by all fat supplements, with no differences in milk CLA and TVA observed among fat supplements. As with milk fat, proportions of ruminal CLA (0.09, 0.26, 0.18, and 0.21 g/100 g of FA) and TVA (2.61, 4.56, 4.61, and 4.39 g/100 g of FA) increased with fat supplements. The effects of fat supplements on ruminal TVA and CLA concentrations were also reflected in rumen FA-salts, free fatty acids, and neutral lipids. The higher TVA to CLA ratio in the rumen compared with milk indicated that fat supplements increased milk CLA concentration mainly by increasing ruminal production of TVA, which also implied the significant role that mammary delta-9 desaturase plays in milk CLA concentrations.     

Lactational response to soybean meal, heated soybean meal, and extruded soybeans with ruminally protected methionine

Seventy-three high producing Holstein cows were arranged in a 3 X 2 factorial to evaluate three protein supplements (soybean meal, heat-treated soybean meal, and extruded blend of soybeans and soybean meal) without or with 15 g/head/d of ruminally protected DL-methionine during wk 4 through 16 postpartum. Total mixed diets contained (DM basis) 30% corn silage, 15% alfalfa hay, and 55% of the respective concentrate mix. Milk production was higher when cows were fed either heated soybean product instead of soybean meal. Methionine supplementation increased production when fed with soybean meal (32.2 and 33.8 kg/d) but not when fed with heat-treated soybean meal (34.5 and 33.0 kg/d) or extruded soybeans (36.2 and 34.4 kg/d). Milk fat percentages were lower with extruded soybeans (3.01, 2.93, and 2.66) and were similar without (2.83) or with (2.90) supplemental methionine. Milk protein percentages were highest when fed soybean meal, lowest with extruded soybeans (3.02, 2.92, and 2.87), and higher with supplemental methionine (2.91 and 2.96). Dry matter intake was higher when fed supplemental methionine (20.0 and 21.3 kg/d). Production of milk in early lactation high producing dairy cows was increased by supplementing a soybean meal diet with ruminally protected methionine or by replacing the soybean meal with heat-treated soybean meal, soybeans, or a mixture of the two.     

Lactational response of dairy cows to increased dietary crude protein with added fat.

Thirty-six Holstein cows were assigned to one of three diets containing soybean meal (16% CP), added fat from extruded soybeans (16% CP), and added fat and protein from extruded soybeans plus soybean meal (18% CP) to determine whether feeding additional protein would prevent the depression in milk protein percentages usually experienced when cows are fed additional fat. Total mixed diets containing 25% corn silage, 25% alfalfa hay, and 50% of respective concentrate mixtures were fed individually wk 4 through 16 postpartum; pretreatment (wk 3 postpartum), milk production, and composition data were used as covariates. Milk production (33.0, 35.8, and 34.2 kg/d) was higher for cows fed added fat. Milk protein (2.92, 2.88, and 2.83%) and casein (2.16, 2.13, and 2.09%) tended to decrease for cows fed added fat and did not increase with higher dietary protein. Dry matter intakes (20.9, 20.7, and 19.8 kg/d) and BW were similar for all diets. Supplementing additional CP to a diet containing added fat did not prevent depression in milk protein percentage.     

Protein degradation in rumen and amino acid absorption in small intestine of lactating dairy cattle fed heat-treated whole soybeans

Four lactating Holstein cows fitted with rumen cannulae and T-type cannulae in proximal duodenum and terminal ileum were used to measure protein degradation in the rumen and amino acid flow and absorption in the small intestine. Soybean meal, whole soybeans, and whole soybeans extruded at 132 and 149 degrees C provided 50% of the protein in diets that contained 51% grain, 36% corn silage, and 13% alfalfa hay (dry matter). Spot samples of digesta were collected from duodenum and ileum during 96 h, and lanthanum was an indigestible marker to estimate flow and digestibility of nutrients. With diaminopimelic acid as a microbial marker, apparent degradations of dietary crude protein in the rumen were 73, 80, 66, and 60% for diets containing soybean meal, whole soybeans, and whole soybeans extruded at 132 and 149 degrees C. Because of the extensive degradation of protein with the raw soybean diet, less total amino acids reached the duodenum, and because of decrease of availability, absorption from the small intestine (g/day) was lowest with this diet. Feeding diets containing extruded whole soybeans increased availability of total essential amino acids in the small intestine compared with diets containing soybean meal and whole soybeans. Absorption from the small intestine (g/day and percent entering) of individual amino acids was generally higher for extruded whole soybean diets.