黄精酸奶降脂作用的实验研究

目的 探讨黄精酸奶对摄食高脂饲料大鼠的降脂作用。方法 SD大鼠64只,雌雄各半,随机为正常组,高脂血症模型组,黄精组,普通酸奶组,阿托伐他汀组,黄精酸奶高、中、低剂量组。正常组喂基础饲料,其余各组喂养高脂饲料并给予相应的药物灌胃,每天1次,连续8周。分别在实验4周、8周后,眼眶釆血,检测血中三酰甘油（TG）、总胆固醇（TG）、低密度脂蛋白（LDL-C）、高密度脂蛋白（HDL-C）水平。结果 4周、8周后测试结果都显示,与模型组相比,黄精酸奶可降低TC、TG、LDL-C,升高HDL-C（P<0.05或P<0.01）,黄精酸奶组的降脂作用优于黄精组、普通酸奶组（P<0.05或P<0.01）。结论 黄精酸奶具有降脂作用,其效果优于单纯食用黄精或酸奶。     

新型复合酸羊乳饮品配方及工艺研究

为确定新型复合酸羊乳饮品的加工工艺、方法及最佳配方。研究选用枸杞、核桃、杏仁、花生和羊奶为原料,采用正交试验研究了新型复合酸羊乳饮品各原料的加工工艺、最佳配方比例、及饮品的稳定性。结果表明:采用枸杞浸提液中枸杞和水的比例为1:8,80℃浸提3次,每次30 min,磨浆后八层纱布过滤;核桃汁中核桃与水的比例是1:2.5,磨浆,八层纱布过滤,胶体磨均质;花生汁、杏仁汁中花生,杏仁和水的比例分别为1:2和1:4,磨浆,八层纱布过滤,胶体磨均质。同时参照酸牛奶的加工工艺,发酵期延长2 h制作酸羊奶。得出新型复合酸羊乳最佳配方为:酸羊奶35%,核桃乳9%,枸杞汁3.5%,杏仁乳3%,花生乳10%,白砂糖5%,纯净水34%,稳定剂CMCNa:0.5%。     

可传一代应用于饮用型酸奶的直投式菌种筛选

利用来源于丹麦科汉森(Chr.Hansen)公司、美国杜邦丹尼斯克(DANISCO)公司和荷兰帝斯曼(DSM)公司的16个混合型直投式菌种,通过传一代前后的菌株比例、发酵活力表现、产品稳定性及感官特性、传一代发酵剂在饮用型酸奶中应用后产品的后酸特性、后风味特性及乳酸菌活菌数稳定性的综合评价,最终筛选出适宜用于传一代应用的最优菌种为DSM公司的CY-124。其传一代后仍然含有较高数量的杆菌,发酵时间在3.5h以内,对发酵活力有着明显改善,且在饮用型酸奶中应用后产品的后酸化特性、后风味特性及菌株数量稳定性良好。     

植物乳杆菌Lactobacillus plantarum（FJAT-7926）生物学特性研究

分离到1株植物乳杆菌FJAT-7926,并对其进行生物学特征研究,结果表明：该乳酸菌的最适生长温度为37℃,最适pH为6。接种量为3％,培养36h后,pH达到3.98,产乳酸量为25.4g·L-1。应用该菌株发酵大豆豆浆,研究发酵后的植物性乳酸菌饮品特性,结果显示：饮品乳酸菌含量高达1×10^9cfu·mL-1,感官评价良好。     

菊粉保健酸奶的研制

菊粉是由D-呋喃果糖以β-2,1-糖苷键连接的多聚果糖,具有改善人体的脂肪代谢,提高矿物质吸收等生理活性。本实验以菊粉为原料,以木糖醇为甜味剂,通过单因素试验和正交试验对菊粉功能性酸奶进行研制。得到的最佳配方为菊粉6%、甜味剂8%、发酵剂2.0%、发酵时间2h。     

可可、咖啡酸奶

可可型、咖啡型酸奶试制成功,在我国加味酸奶中填补了一项空白。特别是搅拌型酸奶,由于易贮运和工业化生产,值得大力推广。     

香菇酸奶的工艺研究

以鲜牛乳和提取的香菇汁为主要原料,加入蔗糖、稳定剂等辅料进行调配,经杀菌后接种乳酸菌进行乳酸发酵,制成香菇酸奶,通过正交试验确定出发酵温度在42℃,接种量为4%,发酵时间4 h,鲜奶与香菇汁的比为2：1,制得的酸奶效果最佳。     

乳铁蛋白及其水解物对直投式乳酸菌发酵剂生长的影响

以直投式乳酸发酵剂为实验菌,研究乳铁蛋白及其水解产物对发酵剂各生长阶段的影响。实验条件为乳铁蛋白质量浓度范围0.5～2.5mg/mL,乳铁蛋白水解物的质量浓度范围0.05～0.3mg/mL,无氧条件下37℃培养。结果表明,37℃恒温培养,乳铁蛋白在0.5～2.0mg/mL范围内对乳酸菌生长有促进作用,最适添加质量浓度为1.0mg/mL,抑菌质量浓度为大于2.5mg/mL;乳铁蛋白水解物在0.05～0.25mg/mL范围内对乳酸菌生长有促进作用,最适添加质量浓度为0.1mg/mL,抑菌质量浓度为大于0.3mg/mL。     

仙人掌酸奶的开发

以鲜牛奶和仙人掌冻干粉为主要原料,再配合其它辅料进行乳酸菌发酵,制成仙人掌酸奶,产品中最大限度地保留仙人掌的各种有效成分。通过正交试验选择出最佳配方,并探讨了生产仙人掌酸奶的工艺条件。     

Influence of preservation methods on the quality of colostrum sourced from New Zealand dairy farms

Abstract

AIMS: To assess the effect of two temperatures (ambient temperature and 4°C), three preservation methods (no preservative, yoghurt and potassium sorbate), and two periods of storage (3 and 7 days) on Brix and total bacterial and coliform counts of colostrum collected from New Zealand dairy farms.

METHODS: One litre of colostrum destined to be fed to newborn calves was collected from 55 New Zealand dairy farms in the spring of 2015. Six aliquots of 150 mL were obtained from each colostrum sample, with two aliquots left untreated, two treated with potassium sorbate and two with yoghurt, and one of each pair of aliquots stored at ambient temperature and the other at 4°C. All samples were tested for Brix, total bacterial counts and coliform counts before treatment (Day 0), and after 3 and 7 days of storage. The effect of preservation method and storage temperature on the change in Brix, bacterial and coliform counts after 3 or 7 days of storage was analysed using multivariable random effects models.

RESULTS: For all outcome variables there was a temperature by preservation interaction. For aliquots preserved with potassium sorbate, changes in Brix and bacterial counts did not differ between aliquots stored at ambient temperature or 4°C, but for aliquots preserved with yoghurt or no preservative the decrease in Brix and increase in bacterial counts was greater for aliquots stored at ambient temperature than 4°C (p<0.001). For aliquots preserved with potassium sorbate, coliform counts decreased at both temperatures, but for aliquots preserved with yoghurt or no preservative coliform counts increased for aliquots stored at 4°C, but generally decreased at ambient temperatures (p<0.001). There was also an interaction between duration of storage and temperature for bacterial counts (p<0.001). The difference in the increase in bacterial counts between aliquots stored at 4°C and ambient temperature after 3 days was greater than between aliquots stored at 4°C and ambient temperature after 7 days.

CONCLUSIONS AND CLINICAL RELEVANCE: Use of potassium sorbate to preserve colostrum for 3 or 7 days resulted in little or no reduction in Brix and a lower increase in total bacterial counts than colostrum stored without preservative or with yoghurt added. Colostrum quality was not affected by storage temperature for samples preserved with potassium sorbate, but storage at 4°C resulted in better quality colostrum than storage at ambient temperatures for colostrum with no preservative or yoghurt added.