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利用木醋杆菌1.1812发酵大豆糖蜜,生产细菌纤维素(BC)。采用单因素和响应面法优化发酵培养基,通过傅里叶红外光谱、扫描电子显微镜和拉伸强度测定仪对细菌纤维的结构和性质进行表征。结果表明,木醋杆菌发酵大豆糖蜜的优化培养基配方:糖蜜可溶性固形物含量4.45°Brix、氮源(m~(蛋白胨):m_(酵母浸粉)=1∶1)24.39 g/L、硫酸镁1.42 g/L、磷酸氢二钠1.95 g/L、柠檬酸0.98 g/L。在此条件下发酵5 d,BC产量为(5.85±0.27)g/L(干基),是基本培养基BC产量【(2.72±0.16)g/L】的2.15倍。与相同条件下基本培养基BC相比,大豆糖蜜培养基不改变BC的化学基团。随着发酵时间的延长,大豆糖蜜BC纤维网状结构愈加致密,拉伸强度显著提高,持水性基本一致(P0.05)。 相似文献
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《食品研究与开发》2015,(16)
以新鲜牛乳和脱臭紫苏蛋白为主要原料,经杀菌、真空浓缩、冷却、添加乳酸菌发酵剂发酵,研发出营养和保健功效高的新型酸奶产品。以感官得分为指标,通过单因素试验,Plackett-Burman因素筛选、结合正交试验设计对生产工艺进行优化。评价了紫苏蛋白粉添加量、乳酸菌添加量、木糖醇添加量、羟甲基纤维素钠(CMC)添加量、发酵温度、发酵时间6个因素对酸奶感官得分的影响。最终确定最优生产工艺为:紫苏蛋白粉添加量5%、乳酸菌添加量0.4%、木糖醇添加量0.55%、羟甲基纤维素钠(CMC)添加量0.2%、发酵温度42℃、发酵时间4 h。该产品具有良好的感官性状,是一种营养丰富,开发前景广阔的产品。 相似文献
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为了利用植物蛋白质资源和提高其营养价值,以豆粕和玉米蛋白粉为原料,应用枯草芽孢杆菌固态发酵制备大豆玉米复配肽。基于豆粕和玉米蛋白粉配比和发酵时间的考察与确定,研究了大豆玉米复配肽的固态发酵工艺条件,又考察了发酵温度、瓶装量、料液比及接种量对蛋白水解度和肽转化率的影响。应用4因素3水平响应面法对大豆玉米复配肽的固态发酵工艺进行优化研究,并分别建立了各因素与蛋白水解度和肽转化率的回归方程。结果表明,最佳固态发酵条件为:发酵温度40℃、瓶装量8.5 g、料液比1:1.2(g/m L)、接种量3.5%(m L/g),在此条件下,蛋白水解度为(32.73±0.17)%,肽转化率为(33.23±0.13)%,与理论预测值基本相符。因此,大豆玉米复配肽的固态发酵工艺是可行的,为大豆玉米复配肽的制备提供了科学依据。 相似文献
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《食品科技》2020,(6)
通过感官评价筛选出植物乳杆菌为最优甘蔗汁发酵菌株。以胞外多糖产量为指标通过单因素试验,选取接种量、发酵温度和发酵时间3个因素进行正交试验,并以多指标综合加权评分法优化发酵工艺,通过测定发酵过程糖类和有机酸等代谢产物含量,研究底物消耗与产物积累关系。结果表明,植物乳杆菌发酵甘蔗汁的最优工艺为甘蔗汁可溶性固形物含量12%,接种量1 g/L,发酵温度35 ℃和发酵时间60 h;植物乳杆菌发酵甘蔗汁72 h期间,甘蔗汁可溶性固形物减少12.5%,蔗糖消耗19.61%,葡萄糖消耗45.36%,消耗48.88%的还原糖,发酵57 h胞外多糖含量达到(4.46±0.28)g/L。发酵过程总酸含量升高主要是由乳酸含量变化引起。 相似文献
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Fifty calves were fed a basal diet of 11.6% crude protein or one of four diets (15.5% crude protein) containing added soybean meal, corn gluten meal, cottonseed meal, or fish meal. Diets were calculated 75% total digestible nutrients. Body weight gain increased an average of 17% with added protein. Fish meal and soybean meal generated highest rates of gain. Ruminal ammonia-nitrogen was higher for soybean meal and cottonseed meal than other diets, indicating greater rates of degradability. Molar proportions of rumen volatile fatty acids were not different among diets, but concentration was lower for fish meal. Serum urea nitrogen was lowest for the basal and fish meal diets. Microbial nitrogen in the abomasum was 33.6% of total nitrogen for corn gluten meal and 42.8% for soybean meal. Apparent dry matter and nitrogen digestibilities were greater for corn gluten meal and fish meal diets than for soybean meal or cottonseed meal diets. Rumen degradability of feedstuffs, as determined by dacron bag technique, ranged from 38.1% for corn gluten meal to 71.3% for soybean meal. Degradability of mixed diets reflected those of the protein supplement present in each diet except for diet containing cottonseed meal. Fish meal and soybean meal were better protein sources for growth of ruminating calves than were corn gluten meal or cottonseed meal. 相似文献
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Twelve midlactation Holstein cows were assigned to a switchback design with 4-wk periods to compare a corn gluten meal and blood meal mixture with soybean meal as supplemental protein sources. All experimental diets contained 60% ammoniated corn silage, on a dry basis, and a corn and oats (2:1) basal concentrate mixture. Diets were: urea control (12.5% CP); soybean meal (16.1% CP); low protein (14.3% CP) corn gluten and blood meal mixture; and high protein (16.8% CP) corn gluten and blood meal mixture. Cows fed the control diet consumed less DM, and produced less milk containing a lower percentage of protein than cows fed other diets. Protein efficiency and milk fat percentage were higher for cows fed the control diet than for cows fed the natural protein diets. Fat-corrected milk and fat yields did not differ among diets. The high protein diets (16.1 and 16.8% CP) decreased protein efficiency and increased SNF percentage. Milk yield per unit of DM intake was higher when cows fed the lower degradable protein source (corn gluten-blood meal) than when they were fed soybean meal. The low degradable protein mixture produced a similar lactation response to soybean meal at both the high and low concentrations of total dietary protein. This study indicates that the dietary protein and undegradable protein concentration needed by midlactation Holstein fed complete mixed diets may be lower than generally recommended. 相似文献
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Effect of rumen protein degradability on milk yield of dairy cows in early lactation 总被引:1,自引:0,他引:1
Twenty-four mature Holstein cows were fed diets of 40% corn silage and 60% concentrate (dry matter) beginning at parturition through wk 16 of lactation. A control concentrate (corn, soybean meal, and barley) was fed through wk 4 followed by assignment of cows to either a concentrate of low or high rumen protein degradability. In situ trials with two fistulated cows fed similar diets yielded rumen protein degradabilities of 78.5, 70.3, 69.9, 67.3, 49.1, and 36.5% for barley, corn, corn gluten feed, soybean meal, brewer's grains, and cottonseed meal. The low degradability concentrate (corn, cottonseed meal, brewer's grains, and corn gluten feed) had an estimated rumen protein degradation of 52.9% and a total ration crude protein of 14.3%. The high degradability concentrate containing corn, barley, and soybean meal was 72.8% rumen degradable, and total ration protein for this treatment was 14.5%. Dry matter intakes were 21.0 and 22.0 kg/day for the low and high degradability diets. Milk yield, fat percent, and fat-corrected milk were not affected by treatment. Milk protein percent and protein yield decreased from 3.00 to 2.84% and 1.07 to .99 kg/day in the high and low degradability diets. Efficacy of use of degradability as a criterion for feed formulation is questioned until understanding of both feed protein breakdown and microbial synthesis is greater. 相似文献
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Nelson E. Lobos Michel A. Wattiaux Glen A. Broderick 《Journal of dairy science》2021,104(6):6620-6632
This trial tested whether rumen-protected Lys (RPL) supplementation would improve the nutritive value of rumen-undegradable protein (RUP) from corn protein. Thirty-two lactating Holstein cows were blocked by days in milk and parity into 8 squares of 4 cows each in replicated 4 × 4 Latin squares. Treatments provided all supplemental crude protein from: (1) soy protein (67% expeller soybean meal plus 33% solvent soybean meal); (2) a blend of soy and corn protein (33% expeller soybean meal, 17% solvent soybean meal, 25% corn gluten meal plus 25% distillers dried grains with solubles); (3) corn protein (50% corn gluten meal plus 50% distillers dried grains with solubles); or (4) corn protein plus RPL [diet 3 top-dressed with RPL (125 g/d of AjiPro-L Generation 1, supplying an estimated 20 g of absorbable Lys/d)]. Diets contained (dry matter basis) 22% alfalfa silage, 43% corn silage, 18% ground high-moisture and dry corn, 2.4% mineral-vitamin premix, 1.5 to 3.9% soy hulls, 15% crude protein, 30 to 32% neutral detergent fiber and predicted to contain equal rumen-degradable protein, RUP, and metabolizable protein. Cows within squares were randomly assigned to treatment sequences and fed diets for 4-wk periods before switching; production data and blood samples were collected during last 2 wk of each period. Data were analyzed using the mixed procedures of SAS. Intake was highest on diet 1, intermediate on diets 2 and 3, and lowest on diet 4; body weight gain was highest on diet 3, intermediate on diets 1 and 2 and lowest on diet 4. Intakes and body weight changes were reflected by differences in milk/dry matter intake, which was highest on diets 2 and 4 and lowest on diet 3. Milk yield was lower on diet 3 (44.3 kg/d) than on diets 1, 2, and 4 (average 45.8 kg/d) and protein yield was highest on diets 1 and 2 (average 1.35 kg/d), intermediate on diet 4 (1.30 kg/d), and lowest on diet 3 (1.25 kg/d). No effects of diet were detected on ruminal metabolites. Free nonessential amino acids and total protein AA were elevated in blood plasma on diet 3, reflecting reduced utilization for milk protein synthesis. These results indicated that 50% dilution of soybean meal RUP with that from corn protein did not reduce yield and that supplementing RPL to the corn protein-based diet increased yield 1.1 kg of milk/d and 50 g of true protein/d. 相似文献
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Effects of source and amount of protein on ruminal fermentation and passage of nutrients to the small intestine of lactating cows 总被引:6,自引:0,他引:6
Four Holstein cows fitted with ruminal and duodenal cannulas were used in a 4 x 4 Latin square to investigate the effects of source (corn gluten meal or soybean meal) and amount (14.5 or 11.0%) of CP on ruminal fermentation, passage of nutrients to the small intestine, and animal performance. Cows wee fed for ad libitum intake a diet of 60% corn silage and 40% concentrate on a DM basis. The treatments, arranged in a 2 x 2 (source x amount of CP) factorial, were 1) 14.5% CP, soybean meal; 2) 11.0% CP, soybean meal; 3) 14.5% CP, corn gluten meal; and 4) 11.0% CP, corn gluten meal. Digestion in the rumen of OM, starch, ADF, and NDF was not affected by source or amount of CP in the diet. Total VFA and NH3 concentrations in ruminal fluid were increased by feeding diets that contained 14.5% CP or soybean meal. FLows of non-NH3 N and amino acids to the duodenum were greater in cows fed the 14.5% CP diets because of a greater flow of non-NH3 nonmicrobial N to the duodenum. Larger amounts of lysine passed to the duodenum when cows were fed soybean meal compared with corn gluten meal. Microbial N flow to the duodenum and efficiency of microbial growth were not affected by treatments, suggesting that ruminal NH3 concentration was not limiting for maximal microbial protein synthesis. Feeding 14.5% CP diets increased the production of milk (29.5 vs. 26.8 kg/d) and milk protein compared with 11.0% CP diets, possibly because of greater passage of amino acids to the small intestine. Feeding soybean meal to cows increased production of milk protein compared with feeding corn gluten meal, possibly because more lysine passed to the small intestine. 相似文献
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中国拟青霉(Paecilomyces sinensis sp nov,PS)属于冬虫夏草中的一个无性型菌株,研究表明其与冬虫夏草在生物活性成分方面十分接近。该文通过单因素和正交试验对中国拟青霉液体深层发酵进行条件优化。对中国拟青霉进行发酵培养,选取菌丝体生物量为指标,确定碳源、氮源和无机盐的最佳比例和最优发酵条件。中国拟青霉液体深层发酵的最佳培养基配比为:玉米粉4.0%、葡萄糖1.5%、黄豆粉2.0%、酵母粉0.3%、KH2PO40.2%、MgSO40.1%、CaSO40.1%、ZnSO40.03%。优化后的菌丝体生物量比优化前提高了1.22倍,而胞内糖肽产量与优化前相比提高了54.0%。 相似文献
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Effect of nitrogen source on mycelial morphology and arachidonic acid production in cultures of Mortierella alpina 总被引:3,自引:0,他引:3
Park EY Koike Y Higashiyama K Fujikawa S Okabe M 《Journal of Bioscience and Bioengineering》1999,88(1):61-67
The effects of nitrogen source on arachidonic acid (AA) production and morphological changes during the culture of Mortierella alpina were investigated using an image analysis system. When yeast extract, gluten meal, or corn steep liquor was used, a circular pellet morphology was obtained. However, when Pharmamedia, fish meal, or soybean meal was used, M. alpina formed radial filamentous mycelia. The radial filamentous area in the case of soybean meal was 75% of the total mycelial area. In a jar fermentor culture, M. alpina morphology varied with the cultivation period: (i) at 0-6 h culture, the inoculated pellet-like mycelia were adapted to the new environment, (ii) at 6 h-1 d culture, filamentous mycelia grew exponentially which yielded a feather-like morphology, (iii) at 1-2 d culture, the filamentous mycelia became disentangled as a result of the mechanical agitation; consequently, the proportion of filamentous mycelia was increased, (iv) at 2-4 d culture, mycelia showed stationary growth, but the AA concentration increased rapidly, and (v) at 4-6 d culture, hyphae grew thick radially with the AA concentration continuing to increase gradually. In the case of the cultures with feather-like morphology obtained using soybean meal, the AA yield was 0.14 g/g dry cell weight, which was two times higher than that in cultures grown using yeast extract. These results suggest that the feather-like morphology of culture of M. alpina is suitable for AA production. 相似文献
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碱性蛋白酶水解脱脂玉米蛋白粉,采用Fenton反应和罗丹明B显色法揭示玉米蛋白粉水解产物(hydrolysate of corn gluten meal,HCGM)对羟自由基的清除活性。以HCGM和蜂蜜为主要原料,添加柠檬酸、苹果酸及明胶,制作可吸果冻。采用单因素试验和正交试验对影响果冻品质的各因素进行研究与分析,通过感官评定确定HCGM蜂蜜可吸果冻的最佳工艺配方为HCGM 2%、蜂蜜8%、柠檬酸0.1%、苹果酸0.05%、明胶2%,所得产品口感爽滑、酸甜可口。 相似文献