低乳糖酸奶的研制

研究了低乳糖酸奶产品的配方组成及其生产工艺条件等。结果表明，该产品除具备有普通酸奶的营养丰富全面、口味酸甜爽口纯正以及凝固性能良好和无褐变等特点外，其乳糖的水解率高达70％以上，可以有效的预防人体乳糖不耐症的发生。     

低乳糖酸奶的研制

主要研究探讨了低乳糖酸奶产品的配方组成及其生产工艺条件等。实验研究结果表明，该产品除具备有普通酸奶的营养丰富全面、口味酸甜爽口纯正以及凝固性能良好和无褐变等特点外，其乳糖的水解率高达70％以上，可以有效地预防人体乳糖不耐症的发生。     

低乳糖酸奶的研制

本文主要研究探讨了低乳糖酸奶产品的配方组成及其生产工艺条件等。实验研究结果表明,该产品除具备普通酸奶的丰富营养、口味酸甜爽口纯正以及凝固性能良好和无褐变等特点外,其乳糖的水解率高达70％以上,     

低乳糖酸奶的研制

本文主要研究探讨了低乳糖酸奶产品的配方组成及其生产工艺条件等。实验研究结果表明,该产品除具备有普通酸奶的营养丰富全面、口味酸甜爽口纯正以及凝固性能良好和无褐变等特点外,其乳糖的水解率高达70％以上,可以有效的预防人体乳糖不耐症的发生。     

低乳糖酸奶的研制

主要研究探讨了低乳糖酸奶产品的配方组成及其生产工艺条件等。实验研究结果表明,该产品除具备有普通酸奶的营养丰富全面、口味酸甜爽口纯正以及凝固性能良好和无褐变等特点外,其乳糖的水解率高达70%以上,可以有效地预防人体乳糖不耐症的发生。     

低乳糖酸奶的研制

本文主要研究探讨了低乳糖酸奶产品的配方组成及其生产工艺条件等。实验研究结果表明，该产品除具备有普通酸奶的营养丰富全面、口味酸甜爽口纯正以及凝固性能良好和无褐变等特点外，其乳糖的水解率高达70％以上，可以有效的预防人体乳糖不耐症的发生。     

低乳糖酸奶的研制

本文主要研究探讨了低乳糖酸奶产品的配方组成及其生产工艺条件睡实验研究结果表明，该产品除具备有普通酸奶的营养丰富全面、口味酸甜爽口纯正以及凝固性能良好和无褐变等特点外，其乳糖的水解率高达70％以上，可以有效的预防人体乳糖不而症的发生。     

低乳糖酸奶的研制

本文主要研究探讨了低乳糖酸奶产品的配方组成及其生产工艺条件等。实验研究结果表明，该产品除具备有普通酸奶的营养丰富全面、口味酸甜爽口纯正以及凝固性能良好和无褐变等特点外，其乳糖的水解率高达70％以上，可以有效的预防人体乳糖不耐症的发生。     

不同温度发酵无乳糖酸奶与普通酸奶差异性比较

通过检测无乳糖酸奶与普通酸奶的酸度、黏度、活菌总数及色泽、滋味和气味的变化,系统比较无乳糖酸奶和普通酸奶的差异性。分别采用37 ℃和42 ℃发酵制备无乳糖酸奶和普通酸奶,检测其发酵和贮存期间酸度、黏度及活菌总数的变化趋势,结合电子鼻、电子舌、电子眼技术检测气味、滋味、色泽的变化。结果表明：发酵期间无乳糖酸奶的酸度增速较普通酸奶快,黏度增加值大。发酵结束后,37 ℃发酵的无乳糖酸奶的乳酸菌数量是普通酸奶的3.50 倍;42 ℃发酵的无乳糖酸奶乳酸菌数量是普通酸奶的2.30 倍。37 ℃发酵酸奶以4094色号为主;42 ℃发酵酸奶以4095色号为主;贮存21 d,酸奶的主色号比例会发生显著性变化（P＜0.05）。37 ℃发酵的无乳糖酸奶与普通酸奶贮存1 d,鲜、甜、苦味存在显著性差异（P＜0.05）;贮存21 d,酸、甜、咸、鲜、苦味均出现显著性差异（P＜0.05）。42 ℃发酵的两种酸奶,贮存1 d时酸、甜、咸、苦味存在显著差异（P＜0.05）;贮存21 d时酸、甜、咸、鲜、苦味均出现显著性差异（P＜0.05）。此外,37 ℃发酵的无乳糖酸奶与普通酸奶在2,3-丁二酮、3-羟基-2-丁酮、乙醇、2-丁酮等气味成分上存在显著性差异（P＜0.05）;42 ℃发酵的两种酸奶在乙醇及2-丁酮上存在显著性差异（P＜0.05）;4 种酸奶在气味上均存在显著性差异（P＜0.05）。综上,不同温度发酵的酸奶之间存在显著性差异,且相同温度发酵的无乳糖酸奶和普通酸奶之间也存在显著性差异。     

不同热处理无乳糖酸奶与普通酸奶品质的比较

确定合适无乳糖酸奶工艺的热处理温度,探究热处理对无乳糖酸奶在表观黏度、色度、滋味、气味、贮藏稳定性以及微观结构影响并与普通酸奶进行比较.结果表明:无乳糖酸奶的表观黏度略高于普通酸奶;在滋味方面,无乳糖酸奶的苦味、咸味、甜味要低于普通酸奶,经过75℃、15 min热处理的无乳糖酸奶风味表现最为协调;在气味和色度方面,不同...     

低乳糖牛奶生产工艺参数的研究

针对乳糖酶缺乏者的乳糖不耐受问题，研究如何生产乳糖水解率为60％以上的低乳糖牛奶。通过38，20，6℃不同水解温度，0．5，0．8，1．0，1．5g／kgN同乳糖酶添加量，不同作用时间等因素的单因素试验，确定了制作低乳糖牛奶的工艺参数。     

酶法生产低乳糖牛奶的工艺条件研究

采用正交实验考察低乳糖牛奶生产过程中乳糖酶用量、酶解时间、酶解温度以及pH值4个因素对乳糖水解率的影响,最终确定乳糖酶用量为1500NLU/L、水解时间为3h、水解温度为38℃、pH为6.8,此时乳糖水解率达到75.2%,酸度与微生物指标也符合要求。同时改进了低乳糖牛奶的后段加工工艺,解决了产品褐变严重的问题。     

延长酸奶保质期的研究进展

酸奶是一种富含营养且具有保健功能的发酵乳制品,但因其含有活性乳酸菌而保质期较短。影响酸奶保质期的主要因素有两方面,即微生物的污染和发酵后酸化。基于以上原因,文章分析了污染微生物的种类及造成的危害,从酸奶加工工艺设备和包装措施的改进以及发酵剂菌种的选育等角度综述了延长酸奶保质期的措施,并为长保质期酸奶的开发应用提供理论基础。 关键词：中图分类号：TS252.54 文献标识码：A 文章编号：0254-5071（20１5）04-0008-05 doi:     

非热处理技术控制酸奶后酸化研究进展

后酸化是影响酸奶货架期内感官品质、风味特征与稳定性的最主要因素之一。非热处理技术是控制后酸化的新兴手段,可以在有效控制酸奶后酸化的同时最大限度保持食品原有的营养特性及感官品质。文章综述了乳酸菌的后酸化机制,对高静压、超声波、脉冲电场、CO₂处理、辐照等非热处理工艺控制后酸化的机理和最新研究进展进行了阐述,并对非热处理技术后酸控制的未来发展方向进行了展望。     

超高温低乳糖牛奶的研制

超高温（UHT）低乳糖牛奶是在利用乳糖酶水解牛奶中乳糖的低乳糖牛奶乳制品，该产品有解决乳糖酶缺乏和乳糖不耐受（吸收不良）的问题。选择了合理、可行的超高温生产工艺。产品有稳定性好、口感佳、营养高等特点。     

Effect of lactose hydrolysis on the milk-fermenting properties of Lactobacillus delbrueckii ssp. bulgaricus 2038 and Streptococcus thermophilus 1131

Yogurt is a well-known nutritious and probiotic food and is traditionally fermented from milk using the symbiotic starter culture of Streptococcus thermophilus and Lactobacillus delbrueckii ssp. bulgaricus. However, yogurt consumption may cause health problems in lactose-intolerant individuals, and the demand for lactose-free yogurt has been increasing. The standard method to prepare lactose-free yogurt is to hydrolyze milk by lactase; however, this process has been reported to influence the fermentation properties of starter strains. This study aimed to investigate the fermentation properties of an industrial starter culture of L. bulgaricus 2038 and S. thermophilus 1131 in lactose-hydrolyzed milk and to examine the metabolic changes induced by glucose utilization. We found that the cell number of L. bulgaricus 2038, exopolysaccharide concentration, and viscosity in the coculture of L. bulgaricus 2038 and S. thermophilus 1131 was significantly increased in lactose-hydrolyzed milk compared with that in unhydrolyzed milk. Although the cell number of S. thermophilus 1131 showed no difference, production of formic acid and reduction of dissolved oxygen were enhanced in lactose-hydrolyzed milk. Further, in lactose-hydrolyzed milk, S. thermophilus 1131 was found to have increased the expression of NADH oxidase, which is responsible for oxygen reduction. These results indicated that glucose utilization promoted S. thermophilus 1131 to rapidly reduce the dissolved oxygen amount and produce a high concentration of formic acid, presumably resulting in the increased cell number of L. bulgaricus 2038 in the coculture. Our study provides basic information on the metabolic changes in starter strains in lactose-hydrolyzed milk, and demonstrates that lactose-free yogurt with increased cell number of L. bulgaricus can be prepared without delay in fermentation and decrease in the cell number of S. thermophilus.     

马铃薯酸奶加工工艺优化

为探讨马铃薯酸奶的加工技术,研究发酵剂接种量、发酵时间、培养温度等工艺参数对发酵效果的影响,并优化发酵工艺条件。结果表明,马铃薯酸奶最佳发酵工艺为:马铃薯浸提液与鲜牛奶体积比20∶70,蔗糖4%(m/V),发酵剂添加量8%(V/V),发酵时间6h。该条件下加工的产品质量最佳。     

Evaluation of lactose oxidase as enzymatic antifungal control for Penicillium spoilage in yogurt

In this study, we investigated the antifungal activity of lactose oxidase (LO) as a potential biopreservative in dairy products. Our study objectives were to screen antifungal activity of LO against common mold strains, to detect the minimum inhibitory level of LO against the same strains, and to understand how LO affects the pH and lactic acid bacteria (LAB) counts in set yogurt. Five mold strains (Penicillium chrysogenum, Penicillium citrinum, Penicillium commune, Penicillium decumbens, and Penicillium roqueforti) were used throughout study. These strains were previously isolated from dairy manufacturing plants. Throughout the study, yogurts were stored at 21 ± 2°C for 14 d. Antifungal activity of LO was screened using 2 enzyme levels (1.2 and 12 g/L LO) against selected strains on the surface of a miniature laboratory set-yogurt model. For all tested strains, no visible mold growth was detected on the surface of yogurts covered with LO compared with control yogurt without LO. The minimum inhibitory level of LO against each strain was further investigated using 4 enzyme levels (0.12, 0.48, 0.84, and 1.2 g/L LO) on the miniature laboratory set-yogurt model. We detected 0.84 g/L LO as the minimum level inhibiting visible hyphal growth across strains. The minimum inhibitory level of LO varied for each individual strain. To study the effect of LO on the pH of yogurt, miniature laboratory set-yogurt models were covered with different enzyme levels (0.12, 0.48, 0.84, 1.2, and 12 g/L LO). At d 14, a difference was detected comparing pH values of treatments to control with no LO. Commercial low-fat set yogurt was used to study the effect of LO on LAB survival when yogurt surface was covered with 0.84 g/L LO under the same experimental conditions. Control with no LO was included. At d 14, 3 levels of catalase were added (0, 0.01, and 0.1%) to each treatment. To enumerate LAB, homogenized samples were plated on de Man, Rogosa, and Sharpe agar and incubated. Yogurts with 0.84 g/L LO had lower LAB counts compared with control yogurts, and catalase level did not have a significant effect on LAB counts. Our results demonstrated potential antifungal efficacy of LO against common spoilage organisms in dairy products with residual lactose and relatively low pH. Manufacturers should establish efficacy of LO against mold strains of interest and determine the effects of LO on organoleptic properties and LAB survival in set yogurt.