羊奶牛奶混合干酪加工工艺研究

为改进羊奶牛奶混合干酪加工工艺,本实验以羊奶粉和鲜牛奶为原料,研究了牛奶添加比例、不同凝乳酶、杀菌条件、酸化条件和氯化钙添加量对混合干酪凝乳效果、出品率和感官品质的影响。结果表明,添加35% 的鲜牛奶,选用羔羊皱胃酶为凝乳酶,巴氏杀菌(63℃,30min),酸化pH6.20,氯化钙添加量为0.02% 时混
合干酪的品质较好。     

豆乳-牛乳混合型新鲜干酪加工工艺优化

将豆奶与牛奶按一定比例混合生产干酪,不仅能保留牛奶干酪的传统风味,还可实现大豆与牛奶所含蛋白质和氨基酸的互补,为人体生长发育、各种生理活动及组织修复提供所需的营养成分,适合中国消费者食用。本实验以豆乳添加量、CaCl2添加量、凝乳酶添加量、预酸化pH值为因素先进行单因素实验,并在此基础上进行L9(34)正交试验,根据凝乳效果(感官评价)进行分析,确定豆乳-牛乳混合型新鲜干酪最佳工艺参数为:豆乳添加量为15%,CaCl2添加量为0.05%,凝乳酶添加量为0.01%,预酸化pH值为5.6。     

响应面法优化“曲拉”凝乳酶干酪素凝乳工艺

以"曲拉"为原料,采用筛选的微小毛霉凝乳酶为凝乳剂,在酶添加量、凝乳温度、凝乳pH值、CaCl2添加量4个单因素试验基础上,利用响应面试验设计法进行试验设计,取得曲拉凝乳酶干酪素出品率与各单因素的函数关系,并建立曲拉凝乳酶干酪素凝乳工艺模型。回归方程和响应曲面结果表明:4个因素对曲拉凝乳酶出品率影响大小依次为:凝乳pH值>凝乳酶添加量>CaCl2添加量>凝乳温度;最佳凝乳工艺为凝乳pH6.2、凝乳酶添加量0.05g/kg、CaCl2添加量2.5%、凝乳温度42℃。在此条件下,曲拉凝乳酶干酪素的理论出品率为75.23%,实验验证出品率为73.54%。     

羊奶干酪出品率的优化

以关中奶山羊所产的鲜羊奶为原料,采用二次回归正交旋转组合设计,对影响羊奶干酪出品率的凝乳酶添加量、酸化条件和氯化钙加加量进行优化,建立了各因子与羊奶干酪出品率关系的数学回归模型,得出最佳的工艺条件为:凝乳酶添加量7259SU,原料乳酸化pH6.4,氯化钙添加量0.03%,羊奶干酪出品率可达10.47%.     

不同因素对羊奶干酪出品率的影响

对影响羊奶干酪出品率主要因素进行了研究。结果表明,原料乳浓度越大,羊奶干酪出品率越高;杀菌条件以巴氏杀菌或高温短时杀菌效果较好;CaCl2添加量以0.02%～0.03%为宜;用犊牛皱胃酶或羔羊皱胃酶为凝乳酶,羊奶干酪的出品率最高。     

工艺过程对牛奶干酪出品率的影响

目的确定提高牛奶干酪出品率的最优工艺条件。方法经三因素二次回归正交旋转组合设计试验,研究凝乳酶添加量、酸度和氯化钙添加量对牛奶干酪出品率的影响。结果建立了各影响因子与牛奶干酪出品率关系的数学回归模型,确定了干酪出品率达到最高值时主要的工艺参数。结论凝乳酶添加量7 266 SU,原料乳酸度27度T,氯化钙添加量0.03%,干酪出品率最高值可达10.04%。     

工艺过程对牛奶干酪出品率的影响

目的 确定提高牛奶干酪出品率的最优工艺条件.方法 经三因素二次回归正交旋转组合设计试验,研究凝乳酶添加量、酸度和氯化钙添加量对牛奶干酪出品率的影响.结果 建立了各影响因子与牛奶干酪出品率关系的数学回归模型,确定了干酪出品率达到最高值时主要的工艺参数.结论 凝乳酶添加量7 266 SU,原料乳酸度27度T,氯化钙添加量0.03%,干酪出品率最高值可达10.04%.     

一种新型凝乳酶生产干酪工艺的研究

采用蓝色刺孢霉所产的新型凝乳酶生产干酪。研究探讨了发酵剂添加量、CaCl2添加量、凝乳酶质量浓度和pH对其凝乳特性的影响。研究确定用新型凝乳酶生产干酪的最佳工艺条件为:发酵剂添加量0.2 g/L,CaCl2添加量为0.02%,pH 5.9,新型凝乳酶添加量为2%。试验中选用的这种新型凝乳酶生产的干酪风味柔和,组织状态细腻,产品质量好。     

软质干酪凝乳特性的研究

研究探讨了软质干酪生产过程中原料乳的比重、CaCl2的添加量、凝乳酶质量浓度以及pH值对其凝乳特性的影响,结果表明:当原料乳比重为1.029g/mL、CaCl2的添加量为0.02%、凝乳酶质量浓度为2.5g/L牛乳、pH值为5.8时可以制作出风味柔和、组织状态细腻的软质干酪。     

玉米胚芽蛋白新鲜干酪的加工工艺

用玉米胚芽蛋白替代部分牛乳,制备新鲜干酪。研究了玉米胚芽蛋白添加量、发酵剂添加量、CaCl2添加量、凝乳酶添加量对新鲜干酪产率的影响。利用响应面分析法优化了工艺参数,即玉米胚芽蛋白液添加量为4%,发酵剂添加量为0.06%,CaCl2添加量为0.04%,凝乳酶添加量为0.04%。生产出的新鲜干酪产率高,质地细腻,酸味清爽。     

Mozzarella干酪内聚性的优化

研究TGase、凝乳酶、CaCl2对Mozzarella干酪内聚性的影响,以优化工艺参数。采用三因素二次正交回归设计确定TGase、凝乳酶、CaCl2的添加量水平,通过SAS软件RSREG过程,分析三因素主效应及其交互效应对成熟10 d的干酪内聚性的影响。结果表明,三因素对内聚性的影响符合Y=B0+∑BjXj+∑BijXiXj+∑BjjX2的三元二次回归模型,其关键参数主效应为TGase(P<0.05)>凝乳酶(P<0.05)>CaCl(2P<0.05);TGase、凝乳酶和CaCl2对干酪内聚性有明显的交互作用。最优工艺参数为:TGase 1.046%,凝乳酶0.817%,CaCl20.075 g/L,内聚性值最大0.628。     

发酵剂、氯化钙及凝乳酶添加量对白牦牛乳Mozzarella干酪质构的影响

以白牦牛乳为原料制作Mozzarella干酪,在单因素试验基础上采用Box-Behnken响应面法对发酵剂、CaCl_2、凝乳酶添加量进行优化,利用质构综合评分筛选最佳的工艺参数。结果表明,白牦牛乳Mozzarella干酪的最佳工艺参数为:发酵剂添加量0.24 g/L、CaCl_2添加量0.23 g/L、凝乳酶添加量0.04 g/L,此时白牦牛乳Mozzarella干酪质构综合评分为11.095,出品率为20.53%,感官评分为93.67。此工艺条件下制作的白牦牛乳Mozzarella干酪香味浓郁,质地均匀,软硬适度。     

解淀粉芽孢杆菌GSBa-1凝乳酶对羊奶干酪成熟特性的影响

为探究解淀粉芽孢杆菌GSBa-1凝乳酶制备的羊奶干酪(干酪B)成熟特性的变化,以采用商业凝乳酶和同批次羊奶制作的干酪(干酪A)为对照组,比较两组干酪在60d成熟期主要组分、质构特性、微生物指标及风味物质的变化。结果表明,两组干酪得率相差不大。成熟期间干酪的水分、蛋白质及脂肪含量呈先上升后下降趋势,干酪B始终高于干酪A;干酪游离氨基酸总量在成熟期间呈先下降后上升趋势,且干酪B中苯丙氨酸、天冬氨酸、异亮氨酸、甲硫氨酸、丝氨酸含量高于干酪A。成熟前期干酪B质构特性优于干酪A。干酪A成熟后乳酸乳球菌数量增加了(5.22±0.02)%,干酪B无显著变化(P>0.05)。成熟期内,两组干酪中挥发性风味物质种类和含量均增加,但干酪B中的壬酸、辛醇、2-庚酮、2-壬酮、二甲基砜使羊奶干酪风味独特、浓郁。因此,GSBa-1凝乳酶具备替代商业凝乳酶用于羊奶干酪生产的潜力,可对干酪风味的形成和品质的提升起到一定促进作用。     

嗜酸乳杆菌发酵生产低脂干酪凝乳工艺的优化

以脱脂乳为原料,采用嗜酸乳杆菌发酵进行预酸化,对其生产的低脂干酪凝乳工艺条件进行了研究。实验选取凝乳pH、氯化钙添加量、凝乳酶添加量、凝乳温度4个影响因素,以干酪产率、乳清中非脂乳固体物质残留量、嗜酸乳杆菌活菌数为指标,采用L₉（3⁴）正交实验进行优化。结果表明,凝乳的最佳工艺参数为凝乳pH6.0,氯化钙添加量0.02%（w/w）,凝乳酶添加量0.01%（w/w,酶活20000u/g）,凝乳温度35℃,以此条件生产的低脂干酪脂肪含量小于5%,干酪产率29.41%,乳清中非脂乳固体物质残留量5.66%,嗜酸乳杆菌活菌数在10⁹cfu/mL以上。     

半硬质干酪加工工艺条件的研究

通过单因素试验和正交优化试验,研究发酵剂添加量、CaCl2添加量、凝乳酶添加量、凝乳温度和盐水浓度对半硬质干酪感官品质的影响,从而得出加工半硬质干酪的最佳工艺条件。结果表明,其最佳工艺参数为发酵剂添加量5%、CaCl2添加量0.02%、凝乳酶添加量3.0 g/100 L、凝乳温度36 ℃、盐水质量分数18%。此最佳工艺条件下得到干酪的感官评分最高为93.25分,干酪产率为10.37%,含盐量为0.74%,含水量为43.58%。香味浓郁、组织细腻、软硬适度、呈现乳白色且有光泽。     

Effect of artisanal kid rennet paste on lipolysis in semi-hard goat cheese

This study examined the use of hygienised kid rennet pastes in model cheese systems and also in goat milk semi-hard cheeses to promote lipolysis. The results obtained indicated that the use of rennet paste caused greater lipolysis and increased, mostly, the short-chain free fatty acid (FFA) content. The model systems made with whole goat’s milk using rennet paste and commercial rennet mixture exhibited a higher FFA content than did the rennet paste-free controls (31,600 vs. 25,600 μmol/kg cheese). For the pilot cheeses made with bovine rennet and rennet paste mixture, the increase in FFA level after 45 days of ripening compared with the cheeses prepared only with commercial rennet was as much as 6600 (μmol/kg cheese) and the increase in the butyric acid content was also 1650 (μmol/kg cheese). Moreover, after 15 days of ripening, industrially prepared cheeses made with rennet paste exhibited greater levels of FFA than did the cheeses made with commercial rennet (11,500 μmol/kg at 45 days of ripening). Their flavour was stronger and the organoleptic characteristics were better accepted, which implies less ripening time for commercial cheese manufacture.     

Short communication: Sensory profile of raw goat milk cheeses made with artisan kid rennet pastes from commercial-weight animals: Alternative to farmhouse goat cheeses

The loss of traditional kid rennet pastes in the Canary Islands (Spain), as in many other regions, is most likely due to the custom of using abomasa from very young animals killed below desirable commercial weight. In addition, the reasonable price of commercial rennets (CR) has resulted in the loss of typical sensory characteristics for most farmhouse raw goat milk cheeses, placing them at a disadvantage when local and international markets are full of different cheeses, often with aggressive marketing strategies. This paper analyzes the sensory characteristics of raw goat milk cheeses made with rennet pastes prepared from commercial kid abomasa in 2 ways: dried while full of ingested milk [full, commercial, artisan kid rennet (FCKR)], or dried after being emptied of ingested milk and refilled with raw goat milk [empty, commercial, artisan kid rennet (ECKR)]. This latter practice allows the use of empty abomasa, or abomasa with grass, soil, and so on. Sensory profiles of cheeses made with FCKR and ECKR rennets were compared with those made with CR by an expert panel (n = 7). The FCKR and ECKR cheeses had similar sensory profiles. Although scores for FCKR cheeses were somewhat higher than for ECKR cheeses, they were in the range found for traditional cheeses made with rennet prepared with abomasa from very young animals. The sensory profile of CR cheeses was very different. Almost 90% of consumer panelists (n = 90) preferred cheeses made with the experimental rennet pastes. These results demonstrate the possibility to prepare artisan rennet pastes from commercial-weight kids in an easy way for farmhouse cheese makers using local resources that would otherwise be destroyed in abattoirs.