基于火麻仁资源综合价值的蛋白提取工艺研究

火麻仁富含油脂、蛋白和微量元素,具有极高的开发价值。本研究从火麻仁油和蛋白得率、脂肪酸及氨基酸含量综合角度,建立资源价值最大化的火麻仁蛋白质提取工艺。对不同榨油方式获得的火麻仁油进行脂肪酸成分分析;比较不同榨油方式所得火麻仁粕提取蛋白的得率、纯度和氨基酸组成差异;通过单因素考察和正交实验优化火麻仁蛋白提取工艺。结果表明火麻仁油富含不饱和脂肪酸,冷榨和热榨对火麻仁油得率和脂肪酸组成无显著影响;碱提酸沉法提取冷榨粕和热榨粕粗蛋白质提取率分别为11.38%和2.23%,纯度分别为79.67%和67.33%;冷榨粕蛋白必需氨基酸含量29.87%,高于热榨粕蛋白的23.93%;通过单因素考察和正交实验研究,火麻仁蛋白最佳提取条件为温度60℃,pH为10.5,提取时间50 min,料液比1:15,在此条件下蛋白得率为20.87±3.16%。研究表明冷榨法能够获得优质火麻仁油和火麻仁蛋白,碱提酸沉法适合火麻仁蛋白的工业化生产,对火麻仁资源综合利用、火麻仁油和蛋白的开发具有借鉴意义。     

不同提取pH条件下火麻仁蛋白组分的功能性质研究

采用碱提酸沉的方法确定不同提取pH条件下得到的火麻仁蛋白组分的等电点,并对其相关的功能性质进行研究。结果表明:提取pH分别为8.5,9.5,11.0,11.5时,相应的火麻仁蛋白组分的等电点为3.5,4.0,5.0,5.5。然而pH为8.5时,蛋白质得率较低,不利于后续试验的进行;pH为11.5时,得到的蛋白质为黄褐色,气味较难闻,不利于得到优质的蛋白质。对不同pH提取得到的蛋白质进行溶解性、持水能力、起泡性和泡沫稳定性进行研究,发现提取pH为9.5和11.0时得到的蛋白质溶解性较好,而持水能力没有太大的差异。由于溶解度的不同,环境pH越接近等电点,起泡性越差,而对应的泡沫稳定性越好,这与蛋白质之间的分子排斥力有关。     

马铃薯淀粉废水中蛋白质的提取研究

实验采用碱提酸沉法与超滤相结合从马铃薯淀粉废水中提取蛋白质。通过单因素实验和响应曲面法优化碱提酸沉工艺,结果表明,碱提酸沉法提取马铃薯淀粉废水蛋白质的最佳工艺参数为:碱提pH9.35,碱提时间59min,酸沉pH3.41,酸沉时间10min。在此条件下蛋白质提取率可达54.24%。酸沉液采用10ku超滤膜进一步提取蛋白,最终总提取率可达93.42%。     

碱溶酸沉法提取梧桐子蛋白质的工艺

以梧桐子为原料,以蛋白质提取率为指标,通过单因素和正交试验,确定碱溶酸沉法提取梧桐子蛋白质的最佳工艺参数。结果表明,影响梧桐子蛋白质提取率的因素大小依次为:浸提时间、浸提温度、料液比和碱提液p H。碱溶酸沉法提取梧桐子蛋白质的最佳工艺参数为:碱提液pH 9、料液比1︰15 (g/mL)、浸提时间120 min、浸提温度40℃。此条件下,梧桐子蛋白质的提取率为31.36%;梧桐子中蛋白质提取液的最佳酸沉pH为3.8。     

超声波辅助碱法提取火麻仁蛋白的研究

本试验以火麻仁粕为原料,分别用碱法和超声波辅助碱法提取蛋白质,经试验结果分析,在固定功率200W,提取温度为25℃时,得出超声波辅助提取的最佳条件为：占空比为20∶20s/s,pH值8.5,料液比为1∶10,超声波辅助浸提时间为30min,蛋白质提取率达83.6%;而单纯碱液提取的最佳条件为：pH值8.5,料液比为1∶10,提取时间为90min,温度为50℃,提取率仅为71.0%。超声波辅助碱液提取麻仁蛋白质的提取率比碱液提高12.6%,可在室温下进行并且大大缩短提取时间。超声波辅助可能是一种有效的蛋白质提取方法。     

从花生蛋白粉中提取花生分离蛋白的条件优化

采用碱提酸沉法从脱脂花生蛋白粉中提取花生分离蛋白,通过单因素试验和正交试验优化了提取工艺条件,确定最佳工艺条件为:浸提温度60℃,料液比1∶9,pH 9.0,浸提时间90 min,酸沉pH 4.5.在此条件下,蛋白质提取率达42.5%,产品纯度为95.65%.所得花生分离蛋白具有良好的功能特性.     

火麻仁蛋白的提取分离及理化性质研究

以脱脂火麻仁粉(defatted hemp seed meal,HPM)为原料,采用两种方法进行火麻仁蛋白(hemp seed protein isolate,HPI)的提取分离,碱提/酸沉法制备得到碱提蛋白(hemp seed protein isolate-alkaline extraction,HPI-AE),盐溶/盐析法制备得到盐提蛋白(hemp seed protein isolate-salt extraction,HPI-SE)。HPI-SE的蛋白含量(94.8%)高于HPI-AE的蛋白含量(85.9%);并且HPI-SE的外观色泽更加亮白。蛋白质凝胶电泳(sodium dodecyl sulfate polyacrylamide gel electrophoresis,SDS-PAGE)结果表明,两种方法提取的火麻仁蛋白主要成分均为火麻仁球蛋白,二者氨基酸组成相似,均含有丰富的精氨酸。不同pH值条件下,HPI的溶解性曲线均呈U型,但是在相同pH值条件下,二者的溶解性存在较大的差异。火麻仁蛋白的起泡性和蛋白质的溶解性呈现出正相关,当pH值远离等电点时,同种电荷的静电斥力提高了蛋白质的溶解性,从而改善了蛋白质的起泡性。荧光光谱显示,在不同pH值条件下,HPI的蛋白构象不随pH值变化发生明显改变,但HPI-SE的荧光强度高于HPI-AE的荧光强度,显示HPI-SE的蛋白质聚集程度高于HPI-AE。     

碱提酸沉法提取牡丹籽饼中蛋白质的研究

以牡丹籽饼为原料,采用单因素试验和正交试验优化碱提酸沉法提取牡丹籽饼中蛋白质的工艺条件。结果表明:牡丹籽饼中蛋白质的最佳提取工艺条件为料液比1∶12、碱液pH 8. 5、提取时间60 min、提取温度45℃,在此条件下牡丹籽蛋白提取率为(78. 23±0. 04)%;牡丹籽蛋白最佳酸沉条件为pH 4. 0,此时蛋白沉淀率达(90. 90±0. 11)%。     

豆制品废水中蛋白质提取与纯化工艺研究

用碱溶酸沉法纯化蛋白质粗品,通过单因素试验和正交试验优化提取工艺。试验得到:在碱溶pH9.0,料液比1∶20(g/mL),提取温度40℃,提取时间1.5h,酸沉pH为3.7的条件下,以10 000 r/min离心蛋白质沉淀率达到89.8%。蛋白质得率为75.5%,纯化后蛋白质纯度达到90.5%,灰分含量为3.76%。     

文冠果油渣中蛋白质的提取工艺研究

分析了文冠果蛋白的氨基酸组成,并以文冠果压榨油渣为原料,采用单因素实验和正交实验优化了碱溶酸沉法提取文冠果蛋白的工艺条件。结果表明：文冠果蛋白含有18种氨基酸,其中谷氨酸(14.25%)、精氨酸(6.00%)和天门冬氨酸(5.08%)的含量较高;采用碱溶酸沉法提取文冠果蛋白的最佳工艺条件为料液比1∶30、提取pH 9、提取时间150 min、提取温度60℃,在此条件下提取2次,蛋白质得率为22.58%;酸沉分离蛋白质的最佳pH为4.6,此条件下蛋白质沉降率为94.67%;通过碱溶酸沉法可使文冠果蛋白的纯度从38.46%提高到84.03%。     

HPLC法测定不同产地火麻仁中五种脂肪酸含量

目的:采用高效液相色谱法对不同产地火麻仁药材中五种主要脂肪酸(α-亚麻酸、亚油酸、油酸、棕榈酸、硬脂酸)进行含量测定,据此对不同产地火麻仁的优劣进行评价。方法:采用Agilent EclipseXDB-C18色谱柱(150mm×4.6mm,5μm),以甲醇-水(85∶15)为流动相,流速1.0mL.min-1,检测波长210nm,柱温30℃。在此条件下,该五种脂肪酸的甲酯化产物与其他组分得到良好的分离,α-亚麻酸甲酯、亚油酸甲酯、油酸甲酯、棕榈酸甲酯和硬脂酸甲酯的进样量分别在42 168μg(r=0.9998)、67267μg(r=0.9995)、9.7 39μg(r=0.9995)、23 94μg(r=0.9996)和14 56μg(r=0.9997)范围内与各自峰面积积分值呈良好线性关系;平均加样回收率分别为99.5%(RSD=0.65%,n=6)、99.5%(RSD=1.20%,n=6)、99.2%(RSD=0.41%,n=6)、99.0%(RSD=0.60%,n=6)和99.5%(RSD=0.61%,n=6)。结论:该法操作简便,结果可靠。不同产地火麻仁油脂中的脂肪酸含量的确具有一定差异,以保定地区的脂肪酸含量为最高,可为火麻仁油脂的合理开发利用提供相关借鉴。     

Straw-thawing method interacts with sire and extender to influence sperm motility and conception rates of dairy cows

Influence of interactions of straw-thawing method with sire and extender type (milk or egg yolk-based) on postthaw sperm motility and conception rates of dairy cows was assessed. In experiment 1, sperm from 10 Holstein sires were frozen in egg yolk citrate and heated whole-milk extenders using a split-ejaculate technique. Straws were thawed in a 37°C water bath with or without 3 min of exposure to a 37°C warming plate while wrapped in a paper towel (air-thaw). Percentage of motile sperm was assessed after 1 min and 3 h of incubation at 37°C. In experiment 2, sperm from 3 Holstein sires were frozen in egg-yolk citrate and a nonheated whole milk extender using a split-ejaculate technique. Straws were thawed and motility was assessed as in experiment 1. Conception rates (n = 475) were compared in a single herd of Holstein cows after thawing straws in 35°C water for 45 s or after air-thawing by wiping straws with a paper towel upon removal from the storage vessel and placing directly into the insemination gun. In each experiment, interactions between thaw method and sire, extender type, or both, indicated that conditions may be created that facilitate sperm tolerance of air-thaw procedures. When a significant thaw method effect was detected in either experiment, air-thaw was consistently associated with the lesser measure of sperm motility, conception, or both. In conclusion, although some sire × extender combinations seem to be tolerant of air-thaw procedures, other combinations are more sensitive, resulting in reduced postthaw sperm survival, conception rates of cows, or both, in response to air-thaw.     

Economic opportunities for using sexed semen and semen of beef bulls in dairy herds

Dairy farmers can increase the number of dairy heifer calves born in their herd by using sexed semen. They can reduce the number of both dairy bull and heifer calves by using beef semen. Long before sexed semen became commercially available, it was believed that it would provide opportunities for increasing genetic level in both herds and populations. In this study, we studied the potential for increasing the genetic level of a herd by using beef semen in combination with sexed semen. We tested the hypothesis that the potential of increasing the genetic level and the overall net return would depend on herd management. To test this hypothesis, we simulated 7 scenarios using beef semen and sexed semen in 5 herds at different management levels. We combined the results of 2 stochastic simulation models, SimHerd and ADAM. SimHerd simulated the effects of the scenarios and management levels on economic outcomes (i.e., operational return) and on technical outcomes such as the parity distribution of the dams of heifer calves, but it disregarded genetic progress. The ADAM model quantified genetic level by using the dams' parity distributions and the frequency of sexed and beef semen to estimate genetic return per year. We calculated the annual net return per slot as the sum of the operational return and the genetic return, divided by the total number of slots. Net return increased up to €18 per slot when using sexed semen in 75% genetically superior heifers and beef semen in 70% genetically inferior, multiparous cows. The assumed reliability of selection was 0.84. These findings were for a herd with overall high management for reproductive performance, longevity, and calf survival. The same breeding strategy reduced net return by €55 per slot when management levels were average. The main reason for the large reduction in net return was the heifer shortage that arose in this scenario. Our hypothesis that the potential for beef semen to increase genetic level would be herd-specific was supported. None of the scenarios were profitable under Danish circumstances when the value of the increased genetic level was not included. A comparable improvement in genetic level could be realized by selectively selling dairy heifer calves rather than using beef semen.     

Genetic consequences of terminal crossbreeding,genomic test,sexed semen,and beef semen in dairy herds

The development of breeding tools, such as genomic selection and sexed semen, has progressed rapidly in dairy cattle breeding during the past decades. In combination with beef semen, these tools are adopted increasingly at herd level. Dairy crossbreeding is emerging, but the economic and genetic consequences of combining it with the other breeding tools are relatively unknown. We investigated 5 different sexed semen schemes where 0, 50, and 90% of the heifers; 50% of the heifers + 25% of the first-parity cows; and 90% of the heifers + 45% of the first-parity cows were bred to sexed semen. The 5 schemes were combined in scenarios managing pure-breeding or terminal crossbreeding, including genomic testing of all newborn heifers or no testing, and keeping Swedish Red or Swedish Holstein as an initial breed. Thus, 40 scenarios were simulated, combining 2 stochastic simulation models: SimHerd Crossbred (operational returns) and ADAM (genetic returns). The sum of operational and genetic returns equaled the total economic return. Beef semen was used in all scenarios to limit the surplus of replacement heifers. Terminal crossbreeding implied having a nucleus of purebred females, where some were inseminated with semen of the opposite breed. The F₁ crossbred females were inseminated with beef semen. The reproductive performance played a role in improving the benefit of any of the tools. The most considerable total economic returns were achieved when all 4 breeding tools were combined. For Swedish Holstein, the highest total economic return compared with a pure-breeding scenario, without sexed semen and genomic test, was achieved when 90% sexed semen was used in heifers and 45% sexed semen was used for first-parity cows combined with genomic test and crossbreeding (+€58, 33% crossbreds in the herd). The highest total economic return for Swedish Red compared with a pure-breeding scenario, without sexed semen and genomic test, was achieved when 90% sexed semen was used in heifers combined with genomic test and crossbreeding (+€94, 46% crossbreds in the herd). Terminal crossbreeding resulted in lower genetic returns across the herd compared with the corresponding pure-breeding scenarios but was compensated by a higher operational return.     

全秆大麻制浆批量生产的实践

在实验室小试和生产试验的基础上,对全秆大麻进行了批量制浆生产, 研究了其纤维形态、化学组成、蒸煮工艺条件、漂白工艺条件等.     

火麻仁饮料的研制

以火麻仁为原料,经热烫、打浆、过滤、调配、均质、杀菌等工艺,制作火麻仁饮料。采用单因素试验和正交设计试验,对火麻仁用量、糖用量、稳定剂种类及用量对火麻仁饮料稳定性的影响进行了探讨。结果表明:在火麻仁5%、白砂糖4%、黄原胶0.1%、CMC-Na0.2%、蒸馏单硬脂酸甘油酯0.06%、蔗糖脂肪酸酯0.2%的条件下,生产的火麻仁饮料风味及稳定性最佳。     

Characterization of semen type prevalence and allocation in Holstein and Jersey females in the United States

Our objective was to characterize semen type prevalence and allocation to inseminate US Holstein and Jersey females by year, parity, service number, and herd size. A secondary objective was to identify the prevalence of beef breed sires selected to create beef × Holstein and beef × Jersey crossbred calves. The final data set included 8,244,653 total inseminations of 4,880,752 Holstein females across 9,155 herds, and 435,267 total inseminations of 266,058 Jersey females across 2,759 herds from October 2019 to July 2021. This data set represents approximately 42 and 27% of the total dairy cows and heifers, respectively, across approximately 40% of the total licensed dairy herds in the continental United States. Holstein and Jersey females were inseminated with 1 of 4 semen types: (1) beef, (2) conventional, (3) sexed, or (4) other dairy. The top 4 beef breeds used to produce beef × Holstein and beef × Jersey crossbred calves, respectively, were Angus (55.1 and 39.1%), Limousin (13.9, and 23.5%), Simmental (11.7 and 20.5%), and Crossbreed Beef (11.3 and 4.8%). From 2019 to 2021, the use of sexed semen to inseminate Holstein and Jersey females increased from 11.0 and 24.5% to 17.7 and 32.1%, respectively, and the use of beef semen to inseminate Holstein and Jersey females increased from 18.2 and 11.4% to 26.1 and 21.2%, respectively. The use of beef semen to inseminate Holstein and Jersey females increased with increasing parity and service number, whereas the use of sexed semen decreased with increasing parity and service number supporting that farmers used sexed semen more aggressively in higher fertility and younger females with greater genetic merit. Overall, the increase in sexed and beef semen inseminations was driven primarily by larger herds. In conclusion, sexed and beef semen inseminations in US Holstein and Jersey females increased from 2019 to 2021 and was allocated differentially based on parity and service number. This increase was driven primarily by larger dairy herds possibly due to differences in reproductive performance and economies of scale.     

Sex-sorted semen for dairy heifers: Effects on reproductive and lactational performances

The objectives of this study were to evaluate the effects of using sex-sorted semen for first AI of heifers on health and productivity during first lactation. Holstein heifers (herd A = 227 and herd B = 1,144) received first artificial insemination (AI) with sex-sorted semen (SX; n = 343) or conventional semen (CS; n = 1,028), and all heifers that displayed estrus after first AI were reinseminated with conventional semen up to 11 times before being culled. Age at first AI was 13.1 ± 0.1 and 13.8 ± 0.1 mo for SX and CS heifers, respectively, in herd A and 12.9 ± 0.1 mo for both SX and CS heifers in herd B. Pregnancy per AI after first AI was greater for CS heifers than for SX heifers (51.8 vs. 40.2%). From heifers initially enrolled, 70.2% calved in herds A (n = 188) or B (n = 774) and first-lactation data were collected. Interval from first AI to calving was greater for SX heifers than for CS heifers (10.2 ± 0.1 vs. 9.9 ± 0.1 mo). Among heifers conceiving to first AI, SX heifers were more likely than CS heifers to deliver a female calf (85.7 vs. 47.7%), but because SX heifers were more likely to deliver a dead calf (8.8 vs. 3.4%), the difference in proportion of SX and CS heifers delivering a live female calf was smaller than expected (SX = 79.1%; CS = 47.2%). Rearing cost from first AI to calving was greater for SX heifers than for CS heifers ($775.3 ± 6.7 vs. $750.0 ± 5.9), but calf revenue tended to be greater for SX heifers ($142.0 ± 7.2 vs. $126.7 ± 6.4) and cost per female calf produced was smaller for SX heifers than for CS heifers ($−809.4 ± 10.8 vs. $−1,249.7 ± 10.9). Treatment did not affect calving difficulty, proportion of heifers needing assistance, and incidence of retained fetal membranes or metritis. Among heifers that conceived to first AI, however, SX heifers were more likely to be culled within 30 DIM (3.3 vs. 1.6%) and tended to be more likely to be culled within 60 DIM (5.5 vs. 3.4%) than CS heifers, but overall replacement cost was not different ($136.8 ± 13.4). Total milk yield (9,245.5 ± 84.7 kg) and income over feed cost ($554.7 ± 5.1) were not different. Overall economic return was greater for SX heifers than CS heifers ($−83.7 ± 36.7 vs. −175.3 ± 33.4). Use of sex-sorted semen for first insemination of virgin heifers reduced the cost per female calf produced and increased the economic return during the first lactation.     

芡实果皮中栲胶提取的初步研究

芡实果皮中栲胶提取的初步研究结果表明：在使用65％的乙醇水溶液,粒度为0.3cm方法,浸提温度选择在60℃,浸出时间选择在2h,乙醇水溶液中的水应使用蒸馏水,加入适量的表面活性剂,浸提液的酸碱性为中性等条件下可得到栲胶9％。     

Exploring the impact of sexed semen on the structure of the dairy industry

Widespread commercial application of sexed semen is expected within the next decade because of continued improvements in fertility of sexed semen and sorting capacity. The objective of this study was to explore the potential impact of widespread application of sexed semen on the structure of the dairy industry in the United States. Historically, female offspring from all heifers and cows were needed to produce enough dairy replacement heifers to replace culled cows. The use of sexed semen allows for a decoupling of breeding decisions necessary to obtain an adequate supply of dairy replacement heifers from those needed to achieve pregnancies needed to start new lactations. Application of sexed semen allows dairy producers to select among their herds’ potential dams and produce dairy replacement heifers from only the genetically superior animals. The rate of genetic progress is expected to increase, but not more than 15% of the rate of gain accomplished through sire selection achieved through conventional (nonsexed) artificial insemination breeding. The supply of dairy replacement heifers is expected to grow to meet and temporarily exceed current demand, resulting in reduced prices for dairy replacement heifers. Consequently, herd turnover rates are expected to increase slightly, and herd expansions may accelerate. The rate of consolidation of dairy farms is expected to increase. Widespread application of sexed semen may temporarily increase the supply of milk, which would result in lower milk prices. The cost of milk production will be reduced as well. Many breeding options exist for the genetically poorer cows in the herd. The optimal breeding mix depends on the value of the various kinds of calves that could be produced. More crossbred calves for beef production may be produced; however, a market for these crossbred calves is not well established. Increased specialization is expected with more dairy producers deciding not to raise their own heifers but to purchase replacements. Other dairy farms might specialize in producing genetically superior dairy replacement heifers for sale. Depending on the value of calves not raised for replacements, artificial insemination organizations might market beef conventional semen or beef male sexed semen to dairy farms. The use of sexed semen should lower the cost of progeny-testing programs and embryo transfer and enhance the value of genetic markers. Eventually, the economic benefits from the use of sexed semen will be passed on to consumers.