云南乳饼加工技术及品质影响因素

云南乳饼作为具有少数民族特色的传统发酵乳制品,其品质优良且工艺简单,极具市场发展前景,但目前仍处于传统手工作坊式阶段,急需实现乳饼的标准化生产.本文首先总结分析了目前乳饼的生产工艺,对其中关键工艺进行阐述,为工艺产业化提供参考;其次综述了影响乳饼品质的因素,包括鲜乳稀释比、凝乳温度和pH、凝乳剂、挤压强度和时间以及外源...     

果蔬乳饼配方及加工工艺研究

乳饼是云南少数民族地区的一种传统山羊奶制品,但产品单一,工艺陈旧,难以满足更多消费者需求。为了丰富乳品市场、开发新型山羊奶制品,本研究在传统乳饼加工的基础上,选用新鲜山羊奶和果蔬汁为原料。采用正交和单因素对比试验筛选果蔬乳饼配方以及加工工艺,结果表明:(1)果蔬乳饼的工艺流程:山羊乳→过滤杀菌→加热→添加CaCl_2→添加果蔬汁→添加白醋→充分搅拌→凝乳→静置→排乳清→压榨→成品;(2)乳饼制作工艺参数:凝乳温度为80℃,CaCl_2添加量为0.025%,点酸水后的pH值为3.8;(3)黄瓜乳饼最佳配方为:羊奶80%,黄瓜汁18%g,糖2%;(4)草莓乳饼最佳配方为:羊奶80%,草莓汁20%,糖适量;西瓜乳饼最佳配方为:羊奶77%,西瓜汁23%,糖适量;(5)桑葚不适宜用于制作紫色乳饼。     

不同凝乳剂对羊奶乳饼质量的影响

通过3种凝乳剂添加量、凝乳温度、时间及成型压力、时间对乳饼工艺和质量的影响研究,筛选了3种乳饼最佳工艺.其中新型凝乳剂(NC)乳饼评分最高,植物凝乳剂(PC)乳饼的香气、口感较好,成品率最高;而传统酸凝荆(TAC)乳饼的硬度较大,但质构较好.NC乳饼钙含量最高(P<0.05),PC乳饼的水分含量较高(P<0.05).凝乳剂对氨基酸、脂肪酸含量以及不饱和脂肪酸所占比例有较大影响(P<0.05).凝乳剂对乳饼蛋白质降解有促进作用,但3种凝乳剂乳饼问差异不明显.     

即食玫瑰再制乳饼的研制

本研究以云南民族特色传统乳制品乳饼为原料,以感官评分为指标,通过单因素试验和响应面优化玫瑰再制乳饼的工艺参数,并分析了产品的感官、理化及微生物指标。结果表明:即食玫瑰再制乳饼最佳工艺参数为:奶粉添加量14%、麦芽糊精添加量3.5%、玫瑰花添加量0.2%、卡拉胶添加量0.3%。玫瑰再制乳饼产品富有独特的奶香味和玫瑰风味,弹性、内聚性、胶着性以及咀嚼性都显著高于作为参照的酸水乳饼(P0.05);其蛋白质含量(24.62±0.62%)、脂肪含量(28.79±0.43%)、水分含量(36.6±0.27%)及微生物指标均符合标准。即食玫瑰再制乳饼产品风味独特、营养丰富、卫生安全、便于携带及食用,可为云南乳饼产业的发展提供参考依据。     

功能型水牛奶乳饼制作工艺的研究

本试验以水牛奶为原料,利用贯筋藤蛋白酶制作乳饼,以Tricine-SDS-PAGE对乳饼蛋白肽进行检测并研究乳饼蛋白肽的抗氧化性。结果表明,酶解辅助酸凝乳乳饼最佳工艺为:加酶量0.03g/kg、酶解时间60min、加酸量20mL/kg,成品率达(23.3±2.54)%。电泳检测酶解辅助酸凝乳(MS-RB)乳饼中有肽水解出来,且该蛋白肽的清除ABTS自由基、DPPH自由基活力和还原能力均高于酸凝乳饼(S-RB)。研制具有功能活性肽的乳饼对云南特色乳制品的开发利用具有一定意义。     

乳饼副产物乳清液制备乳清粉的工艺研究

目的 为了提高云南乳饼副产物乳清液的附加值,使用喷雾干燥技术获得一种新型的高营养价值乳清粉。方法 以乳清液为原料,将溶解度和感官评分作为评价指标,利用单因素结合正交试验确定乳清粉研制最佳工艺条件。结果 当碳酸氢钠用量为0.7%,离心条件3 600 r/min,凝乳pH为6.5,喷雾干燥进风温度180 ℃,蠕动泵数值70 Hz时,研制出的乳清粉中蛋白质13.9%,乳糖49.4%,水分3.3%,灰分6.8%,理化指标及微生物检测结果均符合国标,该乳清蛋白粉溶解性95.18 g/100 g,乳化性72.07%,具有诱人的奶香味,无酸味、异味,色泽呈现均一的淡黄色,口感丝滑,复水性较好。结论 此试验研究为乳饼副产物乳清液的利用提供了途径,为乳清粉的深加工提供了一定的理论依据和参考。     

水牛乳乳饼发酵菌种筛选及工艺优化

为研究水牛乳乳饼发酵菌种筛选及工艺优化,从自然发酵的水牛乳乳清和云南采集乳清样品中分离乳酸菌,并通过产酸、分解蛋白和脂肪能力筛选,获得一株鼠李糖乳杆菌,37℃发酵48 h可使乳清pH值从6.20降至3.60以下,乳清游离脂肪酸110.34μmol/L,蛋白水解度0.180;通过比较乳饼制作过程中原料乳的预热情况、凝乳温...     

云南乳饼、乳扇副产物主要成分及加工特性分析

乳饼、乳扇是云南民族特色乳制品,以二者的加工副产物乳清为原料,通过冷冻干燥技术制得乳清蛋白粉,分析其主要成分及加工特性.结果表明:乳饼副产物获得的乳清蛋白粉中主要成分蛋白质含量39.0％、脂肪含量6.0％、水分含量4.1％、总灰分含量7.7％、酸度23.2?°T、pH?5.61,其加工特性为溶解性99.52％,沉淀率在...     

乳饼酸凝剂的标准化工艺研究

本试验对乳饼加工常用凝乳剂——酸水的理化、微生物指标及乳饼最佳工艺条件进行了研究。通过分析不同地区5家乳饼加工户提供的酸水的理化、微生物指标,研究了酸水的标准化生产参数。结论为:酸水在pH值3.3时,乳饼的成品率最高;酸水与乳清体积比达到5:1以上时,新酸水达到pH值3.3所用的时间较短,适合工厂化循环使用,而且干净卫生。加工乳饼的最佳工艺条件为:牛奶杀菌温度为95℃,酸水添加量为10%,凝乳时间为5min。     

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。     

红枣山羊乳乳扇配方及加工工艺研究

本研究建立了红枣山羊乳乳扇的加工工艺,并对其配方及加工的工艺参数进行了优化。结果表明:(1)红枣山羊乳乳扇的加工工艺:加入食用白醋→加热至65℃→加入灭菌山羊乳→迅速搅拌→形成絮状凝乳→揉搓成团→洗涤→加入白砂糖、大枣粉→混合均匀→制成饼状→入模成型→自然干燥24～48 h→成品。(2)红枣山羊乳乳扇的配方为:食用白醋使用量占鲜羊乳的12%,大枣粉、白砂糖质量分别占凝乳块的10%,5%。     

预酸化对云南乳扇凝乳的影响

本研究利用热处理的酸乳清对牛乳进行预酸化处理,研究酸乳清对乳扇凝乳效果的影响,根据热烫拉伸工艺的需要,控制凝乳的pH值,分析不同的温度和pH值对凝乳效果的影响。结果表明:凝乳温度34℃、凝乳pH值5.2时,酪蛋白流失最少,凝乳效果最好。乳扇加工工艺中通过酸乳清对牛乳进行预酸化处理,可以解决凝乳过程中凝块pH值不固定的问题。     

Milk production,nutrient digestibility and nitrogen balance in lactating cows fed total mixed ration silages containing steam‐flaked brown rice as substitute for steam‐flaked corn,and wet food by‐products

The objective of this study was to evaluate the effect of substituting brown rice grain for corn grain in total mixed ration (TMR) silage containing food by‐products on the milk production, whole‐tract nutrient digestibility and nitrogen balance in dairy cows. Six multiparous Holstein cows were used in a crossover design with two dietary treatments: a diet containing 30.9% steam‐flaked corn (corn TMR) or 30.9% steam‐flaked brown rice (rice TMR) with wet soybean curd residue and wet soy sauce cake. Dietary treatment did not affect the dry matter intake, milk yield and compositions in dairy cows. The dry matter and starch digestibility were higher, and the neutral detergent fiber digestibility was lower for rice TMR than for corn TMR. The urinary nitrogen (N) excretion as a proportion of the N intake was lower for rice TMR than for corn TMR with no dietary effect on N secretion in milk and fecal N excretion. These results indicated that the replacement of corn with brown rice in TMR silage relatively reduced urinary N loss without adverse effects on feed intake and milk production, when food by‐products such as soybean curd residue were included in the TMR silage as dietary crude protein sources.     

奶皮子和奶豆腐的制作工艺及营养价值的研究

奶皮子和奶豆腐是蒙古族地区的两种传统乳制品，研究了奶皮子和奶豆腐的加工工艺，并分析其营养成分。为进一步研制开发民族乳制品奠定了基础。     

Performance of dairy cows fed an entirely organic diet containing cold-pressed rapeseed cake

Abstract

Organic dairy production will be based entirely on organically grown feeds as of 2008, and thereby a demand is created to find suitable feeds that are possible to grow locally. The aim of this experiment was to investigate whether milk yield and milk composition were maintained when cows were fed a 100% organic diet, with around 15% of dietary DM from cold-pressed organic rapeseed cake, compared to a 95% organic diet, in which a conventional protein source was used. Two experimental groups included 20 cows each and the study was carried out during two indoor periods. For cows fed the rapeseed cake diet, milk yield increased by 3.0 kg/day, but contents of milk fat and milk protein of multiparous cows decreased, resulting in similar yields of energy-corrected milk in early lactation. Milk from cows fed rapeseed cake had increased content of unsaturated fatty acids, including conjugated linoleic acid. In conclusion, it is possible to maintain milk production of dairy cows fed 100% organic feedstuffs using cold-pressed rapeseed cake as the main protein source compared to a 95% organic ration.     

The evaluation of the curd forming ability of milk replacers

Inadequate milk curd formation in the abomasum of newborn calves causes malnutrition and diarrhea. In order to define the factors of inadequate curd formation, we compared the curd forming ability among 9 kinds of milk replacers, bulk milk (raw milk), and skim milk both in vitro and in vivo . When rennet was added, the raw milk and one milk replacer formed firm curds. The rest of the milk replacers and skim milk did not form any curd. When a solution of HCl was added, raw milk, three milk replacers and skim milk formed the curd at pH 4.5, but the other milk replacers did not. When HCl was added following the rennet, raw milk, one milk replacer and skim milk formed the curd. In vivo , raw milk, two milk replacers and skim milk showed good curd formation whereas the other milk replacers showed poor curd formation inside the abomasums of the calves. This study showed that most of the milk replacers sold in Japan could not form the curd with rennet.