UHT(超高温灭菌)朱古力牛乳的研制

本文介绍了UHT朱古力牛乳的制作方法及其合理、可行的超高温杀菌生产工艺 ,其主要由牛乳、朱古力、白砂糖、稳定剂等调制而成 ,经长时间观察和尝试发现该产品具有稳定性好、口感佳等特点。     

巧克力风味牛奶的研制与开发

通过选用巧克力香精替代巧克力,以鲜牛奶为主要原料,选用L9(33)正交表,通过正交实验筛选最佳配方。结果表明,鲜牛奶85.0%,复合稳定剂0.16%,巧克力香精0.07%,食用色素0.106%,AK糖0.02%,可可粉0.4%,白砂糖2.0%(均为质量分数,下同)。产品经分析检测符合国家质量卫生标准,口感细腻,巧克力风味浓郁,奶香突出,色泽诱人,是一种很有发展前途的风味牛奶。     

Vitamin A degradation and light-oxidized flavor defects in milk

To determine the effects of light exposure on vitamin A degradation and on light-oxidized flavor development, samples of whole, reduced fat, and nonfat milk were exposed to fluorescent light (either 1000 or 2000 lx) at time intervals of 2, 4, 8, or 16 h. Measurable vitamin A losses occurred at 2, 4, and 16 h at 2000 lx for nonfat, reduced fat and whole milk, respectively. Moderate light-oxidized flavors were detected after 4 h of light exposure (2000 lx) in the whole and reduced fat milk and after 8 h in nonfat milk. The different types of milk show a significant difference in relative flavor scores. By 16 h at 2000 lx, relative light-oxidized flavor development was lower in nonfat milk than in whole or reduced fat milk. The presence of milk fat appears to protect against vitamin A degradation in fluid products, but adversely affects the flavor quality of milk after exposure to light. In summary, these findings demonstrate that even a brief, moderate light exposure (2 h; 2000 lx) can reduce the nutritional value and flavor quality of fluid milk products.     

巧克力风味牛奶的研制与开发

近年来市场上出现的巧克力牛奶一般都是用巧克力加牛奶直接配制而成的,由于巧克力热量高,易导致肥胖、高血脂等疾病,因此在市场上的销售受到了一定的限制。本课题通过选用巧克力香精替代巧克力,以鲜牛奶为主要原料,选用L9(33)正交表,通过正交实验筛选最佳配方。试验结果表明鲜牛奶85.0%,复合稳定剂0.16%,巧克力香精0.07%,食用色素0.106%,AK糖0.02%,可可粉0.4%,白砂糖2.0%。产品经分析检测符合国家质量卫生标准,口感细腻,巧克力风味浓郁,奶香突出,色泽诱人,是一种非常有发展前途的新型风味牛奶。     

Effects of milk powders in milk chocolate

The physical characteristics of milk powders used in chocolate can have significant impact on the processing conditions needed to make that chocolate and the physical and organoleptic properties of the finished product. Four milk powders with different particle characteristics (size, shape, density) and "free" milk fat levels (easily extracted with organic solvent) were evaluated for their effect on the processing conditions and characteristics of chocolates in which they were used. Many aspects of chocolate manufacture and storage (tempering conditions, melt rheology, hardness, bloom stability) were dependent on the level of free milk fat in the milk powder. However, particle characteristics of the milk powder also influenced the physical and sensory properties of the final products.     

HPLC法测定婴儿配方奶粉中维生素A含量的不确定度评定

参照GB5413.9-2010测定婴儿奶粉中维生素A的含量。通过对测定过程中的不确定度来源进行分析,评定出各不确定度分量,最后计算出合成标准不确定度和扩展不确定度,结果表明试样中维生素A含量为15.013μg/g,扩展不确定度为1.496μg/g。不确定度分量结果显示,标准曲线拟合产生的不确定度在不确定度合成中贡献最大,因此在对婴儿配方奶粉中维生素A进行测定时,应对标准曲线的拟合过程加强控制,确保结果的准确性。      

UHT乳贮存过程中V_A和V_C的变化

选择市场上3种UHT乳通过25、37℃和45℃恒温进行贮存温度加速实验比较VA和Vc含量的变化。结果表明,对于VA在3个不同的贮存温度下随贮存时间延长均不断下降,下降速率最高为45℃贮存,最高下降率达到82%,且随贮存温度升高下降越快;贮存中Vc含量变化在3种产品间无差异,且随贮存时间延长略下降,不同贮存温度间变化无差异。对于贮存中UHT乳的品质变化可以选择VA作为指标之一。     

Influence of packaging information on consumer liking of chocolate milk

Chocolate milk varies widely in flavor, color, and viscosity, and liking is influenced by these properties. Additionally, package labels (declared fat content) and brand are some of the extrinsic factors that may influence consumer perception. The objective of this study was to evaluate the effects of packaging labels and brand name on consumer liking and purchase intent of chocolate milk. A consumer acceptance test, conjoint analysis survey, and Kano analysis were conducted. One hundred eight consumers evaluated 7 chocolate milks with and without brand or package information in a 2-d crossover design. A conjoint analysis survey and Kano analysis were conducted after the consumer acceptance test. Results were evaluated by 2-way ANOVA and multivariate analyses. Declared fat content and brand influenced overall liking and purchase intent for chocolate milks to differing degrees. A subsequent conjoint analysis (n = 250) revealed that fat content was a driver of choice for purchasing chocolate milk followed by sugar content and brand. Brand name was less important for purchase intent of chocolate milk than fat or sugar content. Among fat content of chocolate milk, 2 and 1% fat level were most appealing to consumers, and reduced sugar and regular sugar were equally important for purchase intent. Kano analysis confirmed that fat content (whole milk, 1, or 2% fat chocolate milk) was an attractive attribute for consumer satisfaction, more so than brand. Organic labeling did not affect the purchase decision of chocolate milk; however, Kano results revealed that having an organic label on a package positively influenced consumer satisfaction. Findings from this study can help chocolate milk producers as well as food marketers better target their product labels with attributes that drive consumer choice of chocolate milk.     

Tanker milk variability according to farm feeding practices: vitamins A and E, carotenoids, color, and terpenoids

The aim of this work was to study the variability in the composition of bulk milk mixtures of fat-soluble compounds (vitamins A and E, carotenoids, and terpenoids) and assess the links with milk production conditions. Milk from 10 collection trips in the French department of the Haute-Loire (10 to 36 herds per trip) was sampled in the tanker twice during the winter period and 3 times during the grazing season. The collection trips differed in their altitude (440 to 1,150 m) and the forage system (grass or based on corn silage). Vitamins A and E, carotenoids, and terpenoids of the 50 tanker loads of milk were analyzed. Data of milk production conditions in the 204 farms made it possible to constitute indicators for the collection trip and to define 50 mean herds. The relationships between mean herd characteristics (breed, stage of lactation, and feed) and milk characteristics were investigated. The constituents of tanker loads of milk were comparable to those observed in milk produced by groups of animals receiving contrasting diets (rich in concentrate or corn silage vs. pasture). The characteristics of the milk differed according to the period; those produced at grazing were more yellow (1.02 ± 0.4; mean of difference) and richer in β-carotene, lutein, vitamin E (2.0 ± 1.2, 0.23 ± 0.12, and 6.1 ± 5.0 μg/g of fat, respectively), and sesquiterpenes (2.7 ± 2.5) than winter. The variations observed for β-carotene, lutein, and vitamin E were linked to the proportion of grazed grass or grass silage in the forage (r = 0.66, 0.69, and 0.51, respectively), unlike the vitamin A content. During grazing, 20 of the 32 terpenoids identified were associated with the proportion of permanent grassland available for grazing or cut. These results show that feeding is an effective way to modify the quality of dairy products, even in the case of bulk tank milk mixtures. Dairy plants could market different milks, which would contain specific compositions.     

Sensory Characteristics of Milk Chocolate with Lactose from Spray-Dried Milk Powder

Dry whole-milk powders with 0-70% nominal lactose prepared by spray-drying alone (containing amorphous lactose) or combined with post-drying crystallization (containing crystalline lactose) were incorporated into milk chocolate to give 0-50% substitution of lactose for sucrose. No significant differences occurred in sweet, bitter, and thickness of melt (P > 0.10) based on milk powder preparation method or lactose concentration. As lactose increased, hardness and onset of melt increased regardless of milk powder preparation method; but, chocolates containing crystalline lactose were softer than those containing amorphous lactose. Higher chocolate, milk and caramel flavors were perceived in milk chocolates containing crystalline lactose. Graininess of milk chocolate increased at the highest level of added lactose.     

Influence of temperature and fat content on ideal sucrose concentration,sweetening power,and sweetness equivalence of different sweeteners in chocolate milk beverage

The introduction of new products catering to specific dietary needs and the corresponding changes in the consumer profile reflect a growing demand for diet and “light” products. However, little information is available regarding the sensory effects of different sweeteners in products consumed at different temperatures and with varying fat contents. In this regard, this study aimed to determine the influence of temperature and fat content on the ideal sucrose concentration and the sweetness equivalence and sweetening power of different sweeteners: Neotame (NutraSweet Corp., Chicago, IL), aspartame, neosucralose, sucralose, and stevia (95% rebaudioside A), with sucrose as reference, in a chocolate milk beverage using a just-about-right (JAR) scale and magnitude estimation. Increasing temperature of consumption had an inverse effect on the ideal sucrose concentration in whole milk beverages, whereas no difference was noted in beverages made skim milk. In addition, a decrease in sweetening power was observed for all of the sweeteners analyzed considering the same conditions. The findings suggest that different optimal conditions exist for consumption of chocolate milk beverage related to sweetness perception, which depends on the fat level of milk used in the formulation. This information can be used by researchers and dairy processors when developing chocolate milk beverage formulations.