不同排乳清温度对奶豆腐品质影响研究

研究不同排乳清温度对奶豆腐品质的影响,以确定其最佳排乳清温度。采用单因素试验设计,排乳清温度分别为4℃、23℃、32℃、39℃。在其他工艺条件相同的情况下,分别加工一批奶豆腐,然后测定奶豆腐的性能指标。结果表明,随着排乳清温度的增加,奶豆腐的感官评定值先增加,然后逐渐降低;奶豆腐的pH 4.6可溶性氮含量、质量分数12%TCA可溶性氮逐渐下降;游离氨基酸总量先逐渐增加后降低;而pH值和水分含量逐渐降低。以感官评定值为主指标,结合其他性能指标,确定排乳清的最佳温度为23℃。     

不同切割酸度对奶豆腐品质影响研究

研究不同切割酸度对奶豆腐品质的影响,以确定其最佳切割酸度。采用单因素试验设计,切割酸度分别为45°T～50°T、55°T～60°T、65°T～70°T、75°T～80°T、85°T～90°T。在其他工艺条件相同的情况下,分别加工一批奶豆腐,然后测定奶豆腐的性能指标。结果表明,随着切割酸度的增加,奶豆腐的感官评定值先增加,然后逐渐降低;奶豆腐的pH4.6可溶性氮含量、质量分数12%TCA可溶性氮和游离氨基酸总量都逐渐增加;而pH值和水分含量逐渐降低。以感官评定值为主指标,结合其他性能指标,确定切割酸度为65°T～70°T。     

氯化钙的添加量对半硬质干酪品质影响研究

研究氯化钙的添加量对半硬质干酪品质的影响,以确定其最佳添加量。采用单因素试验设计,氯化钙的添加量分别为0、5、10、15、20g/100kg牛奶。在其它工艺条件相同的情况下,分别加工一批干酪,然后测定成熟干酪的性能指标。结果表明,随着氯化钙添加量的增加,干酪的感官评定值逐渐降低;干酪的硬度、pH4.6可溶性氮含量、游离氨基酸总量和水分含量逐渐增加,而pH值变化不大。以感官评定值为主指标,结合其它性能指标,确定氯化钙的最佳添加量为0-5g/100kg。     

奶豆腐生产工艺的优化

在传统工艺的基础上添加发酵剂进行发酵,并筛选出最优工艺参数组合.重点研究了保温时间、发酵剂添加量、切割酸度、排乳清温度对奶豆腐感官评定的影响.结果表明,发酵剂添加量、排乳清温度对奶豆腐感官评定值影响最大,其次为保温时间、切割酸度.     

驼乳和牛乳混合干酪的研制

研究了驼乳和牛乳混合干酪的最佳配方,及成熟期间理化和微生物指标的变化。最佳工艺配方为：牛乳的添加比例为40%,发酵剂的添加量为0.06g/L,CaC12的添加量为0.08g/L,凝乳酶的添加量为0.24g/L,凝乳温度为35℃,凝乳pH为6.1。混合干酪成熟期间,蛋白质、脂肪、乳糖、水分含量降低;硬度、咀嚼性增强,黏着性和弹性下降;pH4.6-SN、12%TCA-SN和5%PTA-SN的含量均有不同程度的上升;发酵剂乳酸菌数逐渐下降,非发酵剂活菌数逐渐升高。     

苹果汁发酵乳饮料的研制

以苹果汁和牛奶为原料,以pH值和感官评分为指标,通过单因素和正交试验,确定苹果汁发酵乳的最优配方及工艺参数。产品的最佳配比:牛奶添加量55%、苹果汁添加量12%、蔗糖添加量5.5%。最佳发酵工艺条件:乳酸菌接种量3.0%、发酵时间5.0h、温度40℃。     

黑糖乌龙茶酸乳的研制及工艺条件优化

以生牛乳和乌龙茶粉为主要原料,添加L-茶氨酸、黑糖和乳酸菌等配料共同发酵,研发黑糖乌龙茶酸乳。通过单因素试验和正交试验分别考察乌龙茶粉添加量、黑糖添加量、L-茶氨酸添加量和发酵剂接种量对黑糖乌龙茶酸乳pH值、酸度、黏度、持水力和感官评分的影响。结果表明：在乌龙茶粉添加量0.3%、黑糖添加量8%、L-茶氨酸添加量0.09%、发酵剂接种量0.010%条件下,黑糖乌龙茶酸乳感官评分为96分、pH 4.54、酸度72°T、持水力67.34%、乳酸菌活菌数5.78×10⁹ CFU/g,产品乌龙茶风味浓郁、色泽明亮、质地细腻、黑糖风味突出、口感香浓顺滑、无颗粒悬浮。     

微贮和氨化处理对西藏主要农作物秸秆饲用品质的影响

文章旨在探究微贮和氨化处理对西藏主要农作物秸秆饲用品质的影响。试验通过选取effective?microorganisms(EM)菌种、秸秆发酵剂,益加益秸秆发酵剂、微贮秸秆发酵剂和2%、4%、8%尿素梯度分别对青稞、油菜秸秆进行处理,并设置无处理对照组,比较不同处理下对微贮秸秆的营养成分、发酵品质的影响。结果表明,青稞秸秆添加秸秆发酵剂和益加益秸秆发酵剂显著降低了中性洗涤纤维（NDF）和酸性洗涤纤维（ADF）含量（P <0.05）,粗脂肪（EE）含量显著提高（P <0.05）。秸秆发酵剂组pH显著低于对照组和EM菌种组（P <0.05）,青稞秸秆添加菌剂组的乳酸、乙酸和丙酸含量显著高于对照组（P <0.05）。添加4%和8%尿素组感官评分较对照组和2%尿素添加组提高;4%和8%尿素添加组pH显著高于对照组（P <0.05）;油菜秸秆4%和8%尿素添加组粗蛋白质（CP）含量显著高于对照组（P <0.05）,青稞秸秆CP含量随尿素添加量的增加显著提高（P <0.05）。结论 ：在本试验条件下,添加秸秆发酵剂和益加益秸秆发酵剂降低了青稞秸秆pH、N...     

葛根酸乳加工工艺

以葛根和复原乳为实验原料,加工制备葛根酸乳。针对影响产品加工的四因素（葛根浆液添加量、发酵剂接种量、发酵时间、发酵温度）进行研究。以产品的感官评分和葛根黄酮含量为指标,通过单因素试验确定较优的四因素加工条件,并在此基础上,进一步通过正交试验,确定葛根酸乳最佳的加工工艺参数为原葛根浆液添加量14%、接种量2.5%、发酵时间4.5h、发酵温度41℃,此时葛根黄酮含量为1.71mg/mL。     

添加不同水平玉米粉对杞柳皮青贮品质的影响

试验旨在研究添加不同水平玉米粉对杞柳皮青贮品质的影响,探讨玉米粉最佳添加量。采用单因素完全随机分组设计,在杞柳皮中分别添加0%(对照组)、5%(Ⅰ组)、10%(Ⅱ组)和15%(Ⅲ组)玉米粉进行青贮,60 d后取样分析青贮常规营养成分和发酵品质,对青贮发酵品质进行综合评分。结果表明:随玉米粉添加量的增加,青贮料粗蛋白质(CP)含量先升高后降低,中性洗涤纤维(NDF)和酸性洗涤纤维(ADF)含量逐渐降低。对照组杞柳皮青贮料pH和NH₃-N/TN最高,分别为4.76和11.09%,显著高于其他3组(P<0.05),分别高18.70%和98.75%、18.11%和96.63%、16.95%和85.76%,水溶性碳水化合物(WSC)含量分别低53.21%(P<0.05)、54.61%(P<0.05)、58.26%(P<0.05)。青贮饲料现场感官鉴定评分和发酵品质综合评价得分顺序均为试验Ⅰ组>试验Ⅱ组>试验Ⅲ组>对照组。在本试验条件下,根据现场感官鉴定以及综合评价青贮饲料发酵品质的各项指标,杞柳皮青贮以添加5%玉米粉效果最佳。     

Evaluation of the nutritional value of glycerol for nursery pigs

In Exp. 1, a total of 144 pigs (BW, 6.68 ± 0.17 kg) were weaned at 21 d, blocked by BW, and allocated to 48 pens with 3 pigs per pen. Pens were randomly assigned to 1 of 6 dietary treatments (0, 2.5, 5, 7.5, and 10% glycerol supplemented to replace up to 10% lactose in a basal starter 1 diet containing 20% total lactose, which was fed for 2 wk), and a negative control diet with 10% lactose and 0% glycerol. A common starter diet was fed for the next 2 wk. In Exp. 2, a total of 126 pigs (BW, 6.91 ± 0.18 kg) were weaned at 21 d of age, blocked by BW, and allocated to 42 pens with 3 pigs per pen. Pigs were assigned to 1 of 6 treatments in a 2 × 3 factorial arrangement in a randomized complete block design with factors being 1) glycerol inclusion in replacement of lactose in starter 1 diets (0 or 5%) fed for 2 wk, and 2) glycerol inclusion in starter 2 diets (0, 5, or 10%) fed for 3 wk. In Exp. 1, glycerol supplementation at 10% improved (P=0.01) ADG (266 vs. 191 g/d) and G:F (871 vs. 679 g/kg) during the starter 1 period when compared with the negative control. Incremental amounts of glycerol linearly (P<0.05) increased ADG and ADFI, but did not affect G:F during starter 1. There was no effect of feeding glycerol during the starter 1 phase on subsequent performance during the starter 2 phase or overall. Serum glycerol concentrations increased linearly (P=0.003) with increasing dietary glycerol, and serum creatinine (P=0.004) and bilirubin (P=0.03) concentrations decreased with increasing glycerol. In Exp. 2, glycerol did not affect performance during starter 1, but it linearly increased (P≤0.01) ADG and ADFI during starter 2 (464, 509, and 542 and 726, 822, and 832 g/d, respectively) and overall (368, 396, and 411 and 546, 601, and 609 g/d, respectively). At the end of the study, pigs were 1.0 and 1.5 kg heavier when fed 5 and 10% glycerol, respectively (linear, P<0.01). Serum glycerol concentrations increased linearly during starter 2 (P<0.001), but were not affected during starter 1. Glycerol supplementation increased serum urea N quadratically (P<0.001) and decreased creatinine linearly (P<0.05) in the starter 2 phase. Overall, data indicate that glycerol can be added to nursery pig diets at 10%, while improving growth performance.     

Digestible lysine requirement of starter and grower pigs

Three experiments were conducted to determine the digestible lysine requirement of starter (6 kg BW initially) and of grower (21 kg BW initially) pigs. Experiment 1 used 294 starter pigs and lasted 28 d; Exp. 2 used 182 grower pigs and lasted 35 d. Protein and total lysine contents of the basal corn-peanut meal diets were 20 and .8% for Exp. 1 and 16 and .54% for Exp. 2. Basal diets were fortified with five incremental additions of lysine.HCl to provide lysine contents ranging from .8 to 1.3% in Exp. 1, and .54 to .94% in Exp. 2. Diets contained crystalline tryptophan, threonine and isoleucine (Exp. 1 only) to provide dietary concentrations equal to 18, 70 and 60% of the highest lysine level fed. Average daily gain and gain/feed of both starter and grower pigs increased (P less than .05) linearly and quadratically as dietary lysine level increased. For starter pigs, ADG and gain/feed were optimized at 1.1 to 1.2% total lysine. For grower pigs, ADG and gain/feed were optimized at .86% total lysine. In Exp. 3, barrows fitted with an ileal T-cannula were used in a 4 X 4 Latin square design. Basal diets and diets with added lysine were evaluated. Apparent lysine digestibility of the basal starter and grower diets and lysine.HCl were 79.9, 74.1 and 96.7%, respectively. Based on these values and the total lysine contents found to optimize performance, the digestible lysine requirements of starter and grower pigs are 1.03 and .71%, respectively.     

Subsequent bone and metabolic responses of broilers to high-non-phytate phosphorus diets in the starter period

1. An experiment was performed to elucidate the subsequent effects of high-non-phytate phosphorus (NPP) diets on growth performance, blood metabolites, bone characteristics and P retention of broilers fed on low-NPP grower diets. The 42-d study was designed as a 2 × 2 × 2 + 1 factorial, which included two starter NPP concentrations (4.5 and 5.5 g/kg; d 0–21), two grower NPP concentrations (1.5 and 2.3 g/kg; d 22–42), with or without phytase (1000 FTU/kg), with a reference diet containing an adequate NPP concentration over the course of the trial.

2. In the starter period, growth performance and P retention were not affected by experimental diets. The high-NPP diet increased plasma P concentration, increased tibia ash and tibia P contents and decreased plasma alkaline phosphatase (ALP) activity at d 21.

3. No significant interaction was observed between NPP concentrations in the starter and grower periods and phytase. The main effect data indicated that the increase in NPP concentration in the starter diets had no effects on growth performance in the grower period and overall. The high-NPP diet in the early stage of growth reduced plasma P concentration, plasma ALP activity and tibia ash content at d 42. The main effect data also showed that exogenous phytase increased body weight gain in the grower period and overall.

4. It can be concluded that feeding increased NPP diets have no effects on growth performance in the starter period. This feeding strategy results in negative effects on plasma P concentration and bone ash content at d 42. Also, exogenous phytase is effective in improving growth performance, bone characteristics and apparent P retention of growing broilers fed diets that are inadequate in phosphorus.     

Influences of wet feeding and supplementation with ascorbic acid on performance and carcass composition of broiler chicks exposed to a high ambient temperature.

In two experiments was investigated whether feeding with an air-dry feed mixed with different amounts of water and/or supplemental ascorbic acid affect performance and carcass compositions of broilers exposed to a high ambient temperature (35 to 37 degrees C for 8 h/d and thermoneutral for 16 h/d). In the first trial, 64 one-week-old male broiler chicks were fed ad libitum in four dietary treatment groups for a 6-week period. Experimental mash diets were prepared by mixing a maize-soybean based standard broiler starter or finisher with tap water in the ratios of 0.0:1.0, 0.5:1.0, 1.0:1.0 and 1.5:1.0 (water:air-dry feed, w/w). More water in the diet increased BWG, DMI, abdominal fat and carcass weight, carcass CP, crude fat, but it deteriorated DM conversion efficiency. In the second experiment, 64 one-week-old male broiler chicks were given air-dry or wet (water:feed, 1.5:1) starter or finisher diets without or with ascorbic acid supplementation (0 and 250 mg/kg air-dry feed, resp.) ad libitum for a 6-week period. Ascorbic acid supplementation increased BWG, carcass weight and carcass CP significantly, while reducing carcass crude fat content. However, feeding broilers with a diet mixed with water in a ratio of 1.5:1.0 increased BWG, DMI, carcass weight and carcass lipid markedly, but deteriorated DM conversion efficiency. There was also a significant interaction between ascorbic acid and wet feeding, whereby ascorbic acid supplementation induced a significant reduction in carcass lipid contents of broilers fed on air-dry diets but not on wet diets. It is concluded that wet feeding, especially an addition of 150% water to produce a porridge like consistency, improved growth performance by increasing fat, ash and protein deposition in the body, while reducing DM conversion efficiency. It is also concluded that under heat stress supplemental ascorbic acid in air-dry diets stimulates broiler performance but not in wet diets.     

Effect of dietary levels of rapeseed meal and polyethylene glycol on the performance of male broiler chickens

1. In a 5 × 2 factorial experiment, the performance of male broiler chickens given starter (1 to 21 d) and finisher (21 to 42 d) diets containing five concentrations (0, 74.5, 149.0, 223.5 and 298.0 g/kg) of rapeseed meal (RSM) and two concentrations (0 and 15 g/kg) of polyethylene glycol (PEG) was measured.

2. Bodyweight gain and food intake decreased (P<0.01) with increasing dietary RSM both in the starter and finisher phases.

3. The relative weights of thyroid glands, liver, heart and the ratio of water to food intake increased (P<0.01) while the dressing percentage, abdominal fat‐pad weight and the feather condition score decreased (P<0.01) with increasing dietary RSM.

4. The mortality rate was increased (P<0.05) on diets containing 149 g/kg or more of RSM. The main causes of deaths and culling on the high RSM diets were enlarged livers and hearts, liver haemorrhage and leg disorders.

5. The inclusion of 15 g/kg PEG in the starter diets increased (P<0.01) bodyweight gains and food intake. It also increased (P<0.05) water consumption between 37–39 d, faecal moisture content at 40 d and the haemoglobin content in blood.

6. There were no interactions between the dietary concentrations of RSM and PEG on growth and other variables measured.     

The use of barley in choice feeding of the Turkey

1. Two‐choice feeding of the male turkey from 50 d of age was investigated using pelleted barley and a turkey starter diet, whole barley and the starter diet, a ground barley‐based turkey finisher diet and the starter diet, pelleted barley and a series of complete diets and compared with feeding the series of complete diets alone.

2. For turkeys on the first four treatments on average 21%, 21%, 42% and 5% by weight, respectively, of food consumed was the barley alternative.

3. There were no significant differences in final body weight between turkeys on choice treatments and those receiving the series of complete diets alone.     

The nutritive effect of avilamycin in swine breeding and fattening

During a total period of treatment of 141 days, divided into starter grower and fattening period, the efficacy of avilamycin in a dosage of 80 mg/kg (starter grower) and 20 mg/kg (fattening) rsp. 40 mg/kg and 20 mg/kg was investigated in comparison with a negative control group and the additive tylosin. Growth was partially significantly increased by avilamycin at a dosage of 40 mg/kg/20 mg/kg compared to the control. Average daily weight gains of the starter grower period were improved for about 12%, feed conversion ratio for about 14%. In spite of a clear decrease in the efficacy of the additive during fattening period, a superiority of the avilamycin-group over the control- and the tylosin-group could be saved when avilamycin was added till the end of the fattening period. So addition of avilamycin in a dosage of 40 mg/kg during starter grower and 20 mg/kg during fattening period can be recommended.     

Growth performance of broilers fed on diets containing processed poultry wastes

1. Broilers were grown on diets containing processed poultry wastes: dehydrated broiler litter, with (DBLA) or without (DBLN) arsenical residues, “in‐house” dried waste (IHDW) and dehydrated layer waste (DLW), all from commercial poultry houses.

2. Wastes were included at 100 g/kg in starter and finisher diets given, in most cases, from 0 to 8 weeks. In formulation the contents of true protein and of experimentally‐determined metabolisable energy values were used to ensure nutritional balance.

3. Body weight at 8 weeks with inclusion of wastes was equivalent to control (DLW) or increased (DBLA, DBLN). The gain: food ratio was reduced by the two layer wastes because of increased food consumption. Litter moisture was increased by the feeding of wastes.