Quality and acceptability of a set-type yogurt made from camel milk

Camel milk (CM) set yogurts were formulated with gelatin, alginate (ALG), and calcium (Ca). Titratable acidity, pH, sensory properties, and acceptability of CM yogurts were studied. Twelve treatments were prepared; 3 using gelatin at 0.5, 0.75, and 1% levels and 9 with combinations of ALG and Ca at different levels. Titratable acidity and pH of fresh yogurt were not affected by the addition of gelatin or the ALG and Ca combinations. Trained sensory panel results showed that CM yogurt containing 1% gelatin or 0.75% ALG + 0.075% Ca had the highest intensities for firmness and body. Consumer results indicated that the hedonic ratings of the sensory attributes and acceptability of CM yogurt containing 0.75% ALG + 0.075% Ca were similar to that of cow's milk yogurt. The CM yogurts containing ALG + Ca and flavored with 4 different fruit concentrates (15%) had similar hedonic ratings and acceptability. Addition of 0.75% ALG + 0.075% Ca could be used to produce acceptable plain or flavored CM yogurt.     

消费者感官评价对酸奶品质提升的导向研究

消费者感官评价为产品开发和工艺改良提供实际依据。本文以酸奶为例,结合消费者感官测试完成其品质提升。分别收集消费者的基本信息,以及他们对酸奶整体喜好度、香气喜好度；香气、甜味、酸味、稠度接受度；和酸奶所需要提升的感官属性的主观建议等。结合喜好度分析、惩罚分析、词云频率等数据分析方法,得到消费者对酸奶的品评结果。实验结果表明四种酸奶的整体喜好度与香气喜好度平均值都在5分以下,说明消费者的认可度不高；且酸奶的香气与整体喜好度之间有正相关性。酸奶661和467的产品更受消费者的欢迎。由于这两者目前的喜好度分值仍较低(<5.0),需要进一步优化其配方,以期获得更好的市场价值。消费者关注的酸奶品质主要包括酸度、甜度、香气和稠度。喜好度分析和接受度惩罚分析的结果发现酸奶467是目前消费者喜好度较高的产品,后期通过降低其酸度,可以更好地提高它的接受度,从而获得更多消费者的青睐。以消费者为导向探究乳制品的风味感官品质,为产品的优化升级提供指导意义。未来通过调试酸奶的风味性质可生产出深受消费者喜爱的产品。     

红枣多糖对乳酸菌发酵及酸奶品质的影响

以红枣多糖为研究对象,通过测定酸奶中乳酸菌活菌数、酸奶酸度、乳清析出率、持水力及感官等指标,研究红枣多糖对乳酸菌发酵酸奶在发酵、贮藏过程中品质的影响。研究结果表明:当红枣多糖添加量为1.0%时,可促进乳酸菌的生长,红枣多糖酸奶的酸度在贮藏期间的变化最小,持水力高、可达77%,乳清析出率最低,为4.40%;在不同温度贮藏的过程中,红枣多糖酸奶的p H、乳清析出率、持水力以及感官品质的变化均低于未添加红枣多糖的酸奶。红枣多糖一定程度上可延长酸奶的酸化过程、延长保质期。本实验通过探索红枣多糖对乳酸菌发酵和酸奶品质的影响,以期为红枣多糖酸奶的制作提供理论和技术依据。      

搅拌型猕猴桃、红枣汁复合保健酸奶的研制

以猕猴桃、红枣汁和鲜乳为主要原料,对搅拌型果汁酸乳的生产工艺进行了系统研究.通过鲜乳发酵,然后再加入果汁,得出搅拌型酸乳的最佳工艺条件为采用90～95℃、10min热处理牛乳,接种量2%,在42℃下培养3.5h,加8%蔗糖、5%猕猴桃汁、10%红枣汁,以0.2%耐酸CMC-Na作为稳定剂,在72～75℃、5～10min对成品进行杀菌.     

不同发酵剂对黑枣酸奶品质的影响

使用不同益生菌组合制备黑枣酸奶,并探究不同益生菌组合对发酵和质构特性的影响。结果表明,不同益生菌组合会显著影响黑枣酸奶的理化指标和质构特性（P＜0.05）;相比传统酸奶发酵剂,强化植物乳杆菌、嗜酸乳杆菌和乳双歧杆菌（1∶1∶1）发酵可显著提高黑枣酸奶的可滴定酸度（46.48%）、持水力（4.75%）、可溶性固形物含量（3.85%）和胞外多糖含量（12.63%）。此外,益生菌强化发酵可使黑枣酸奶中乳酸菌活菌数达到9.63 lg CFU/mL,且有效改善黑枣酸奶的质构特性,其硬度值、弹性、内聚性和回复性分别为151.24 g、1.04 mm、0.96 g·s和0.28。     

黑豆酸奶工艺条件的研究

以牛奶、黑豆为主要原料,通过单因素试验和正交试验,确定了黑豆酸奶的最佳工艺参数,即牛奶、豆汁比7:3,黑豆汁浓度10％,蔗糖添加量80g/L,复合稳定剂添加量1.5g/L,混合菌种接种量50g/L,发酵温度46℃.此条件下发酵的黑豆酸奶具有清香纯净的乳酸味,组织状态细腻,质地均匀,无气泡,硬度适中,少量乳清析出,具有黑豆特有的豆香味且酸甜适口.     

Developing a strawberry yogurt fortified with marine fish oil

Fortified dairy products appeal to a wide variety of consumers and have the potential to increase sales in the yogurt industry and help increase intake of long-chain n-3 fatty acids. The objectives of this study were to develop a strawberry yogurt containing microencapsulated salmon oil (MSO; 2% wt/vol) and evaluate its characteristics during 1 mo of storage. Unpurified salmon oil (USO) was purified (PSO) and both USO and PSO were analyzed for peroxide value (PV), anisidine value (AV), total oxidation, free fatty acids (FFA), and moisture content. A stable emulsion was prepared with 7% PSO, 22% gum arabic, 11% maltodextrin, and 60% water. The emulsion was spray-dried to produce MSO. The MSO was added to strawberry-flavored yogurt (SYMSO) before pasteurization and homogenization, and a control (SY) without MSO was produced. Both yogurts were stored for 1 mo at 4°C and we determined the quality characteristics including acidity (pH), syneresis, thiobarbituric acid (TBA), fatty acid methyl ester composition, color, and lactic acid bacteria (LAB) count. The entire experiment was replicated 3 times. Total oxidation (unitless) of USO, PSO, and MSO was calculated to be 20.7 ± 1.26, 10.9 ± 0.1, and 13.4 ± 0.25, respectively. Free fatty acid contents were 1.61 ± 0.19%, 0.59 ± 0.02%, and 0.77 ± 0.02% for USO, PSO, and MSO, respectively. Eicosapentaenoic acid and docosahexaenoic acid were the predominant polyunsaturated fatty acids in MSO and in SYMSO, but neither was detected in SY. Fortification of SY with MSO had no significant effect on yogurt pH or syneresis. A decrease in concentration of lactic acid bacteria was observed during the storage of all yogurts. Thiobarbituric acid values significantly increased as storage time increased and SY had a significantly lighter (higher L*) and less yellow (lower b*) color than SYMSO. Although some slight differences were observed in the color and oxidation of SYMSO compared with SY, the study demonstrated that SY could be fortified with salmon oil.     

姜汁酸奶饮料的研制

以药食兼用的保健食品一生姜作为原料,和酸奶调配研制营养风味俱佳的姜汁酸奶保健饮料。通过单因素实验,正交实验和配方组合的优化既确定了该饮料的最佳生产工艺,又筛选出了较好的饮料配方组合,制作出的产品风味口感和稳定性均较好。实验对生姜的处理方法和出汁率,饮料配方,糖酸比,饮料稳定性等关键因素进行了较详细的研究和探讨。经多次实验和感官鉴评确定,饮料的最佳配方为酸奶35％,姜汁8％,白糖11％,并调节糖酸比至26左右时酸甜适度,口感良好。单一的稳定剂稳定效果很差,选用配比为（黄原胶：羧甲基纤维素钠：海藻酸钠=1：2：1）的复合稳定剂,总用量为0.3％时稳定效果良好。85℃杀菌10min时,既可获的满意的杀菌效果又对饮料的稳定性影响较小。     

大豆多肽豆酸奶的的研制

研究使用不同直投式发酵剂以及添加大豆多肽作为促进剂对豆酸奶产品感官品质和酸度的影响,初步探讨大豆多肽在豆酸奶中的应用.实验结果表明,在200mL的豆酸奶中选择Hansen YF-L811作为发酵剂,其添加量为0.02 g,蔗糖添加量为5～7 g,大豆多肽为1 g时,可获得感官品质较好的大豆多肽酸奶产品.制品中酸度的变化与大豆多肽添加量存在密切联系.添加大豆多肽作为促进剂,在豆酸奶的应用中具有一定的可行性.     

Textural and sensory characteristics of whole and skimmed flavored set-type yogurt during long storage

A study of refrigerated storage (10°C for 91 d) of whole and skimmed flavored set-type yogurt was made. Comparison with storage at 20°C for 21 d and 30°C for 3 d (accelerated) was also carried out. Refrigerated storage yogurts were assessed by a trained panel and by a consumer panel. Trained-panel scores were correlated to instrumental data, and the acceptability data for long storage were studied using consumer criteria. In all cases, after-storage pH values barely changed over storage time, indicating that the yogurt samples did not develop much acidity under any of the storage conditions studied. The profile of the instrumental texture curves obtained corresponded to a firm gel, which broke after a plunger penetrated the sample, and the firmness values of the whole yogurt were lower than for the skimmed yogurt under all the storage conditions studied. From a microbiological point of view, the viability of the yogurts was adequate at the different storage times and temperatures studied, although those stored at 10°C for long periods would not comply with some countries’ minimum requirements. Logistic regression of the data from a 50-consumer sensory evaluation showed that the probability of the whole yogurt being accepted after 91 d storage at 10°C was around 40%, whereas for the skimmed yogurt it was only 15%, largely because the skimmed yogurt developed certain negative attributes at an earlier stage of storage than the whole yogurt.     

Fortification of sweetened plain yogurt with insoluble dietary fiber

 Seven types of insoluble dietary fiber from five different sources (soy, rice, oat, corn and sugar beet) were used to fortify sweetened plain yogurt. Fiber addition caused an acceleration in the acidification rate of the experimental group yogurts, and most of the fortified yogurts also showed increases in their apparent viscosity. Soy I and sugar beet fibers caused a significant decrease in viscosity due to partial syneresis. In general, fiber addition led to lower overall flavor and texture scores. A grainy flavor and a gritty texture were intense in all fiber-fortified yogurts, except in those made with oat fiber. Oat II fiber gave the best results; differences with controls in terms of flavor quality scores not being statistically significant. The evolution of organic acids during the fermentation and cold storage of control and oat-II-fiber-fortified yogurts showed a similar pattern; only acetic and propionic acids were found in significantly higher amounts in the fiber- fortified product. Received: 27 June 1996/Revised version: 2 September 1996     

高纤高粘搅拌型刺梨酸奶的加工工艺

以新鲜优质牛奶为原料,添加刺梨果酱与水溶性膳食纤维,将保加利亚乳杆菌及嗜热链球菌以1:2混合作为发酵剂,研制出具有浓郁刺梨风味的高纤高粘搅拌型酸奶。     

Fortification of sweetened plain yogurt with insoluble dietary fiber

 Seven types of insoluble dietary fiber from five different sources (soy, rice, oat, corn and sugar beet) were used to fortify sweetened plain yogurt. Fiber addition caused an acceleration in the acidification rate of the experimental group yogurts, and most of the fortified yogurts also showed increases in their apparent viscosity. Soy I and sugar beet fibers caused a significant decrease in viscosity due to partial syneresis. In general, fiber addition led to lower overall flavor and texture scores. A grainy flavor and a gritty texture were intense in all fiber-fortified yogurts, except in those made with oat fiber. Oat II fiber gave the best results; differences with controls in terms of flavor quality scores not being statistically significant. The evolution of organic acids during the fermentation and cold storage of control and oat-II-fiber-fortified yogurts showed a similar pattern; only acetic and propionic acids were found in significantly higher amounts in the fiber- fortified product. Received: 27 June 1996/Revised version: 2 September 1996     

Physical properties of yogurt fortified with various commercial whey protein concentrates

The effects of whey protein concentrates on physical and rheological properties of yogurt were studied. Five commercial whey protein concentrates (340 g kg^?1 protein nominal) were used to fortify milk to 45 g protein kg^?1. Fermentation was performed with two different starters (ropy and non‐ropy). Resulting yogurts were compared with a control yogurt enriched with skim milk powder. The water‐holding capacity of the yogurt fortified with skim milk powder was 500 g kg^?1 and ranged from 600 to 638 g kg^?1 when fortified with whey protein concentrates. Significant rheological differences have been noticed between the yogurts fortified with different whey protein concentrates, independent of the starter used. Three whey protein concentrates generated yogurts with a behavior similar to the control. The two others produced yogurt with lower firmness (15 g compared with 17 g), lower Brookfield viscosity (6 Pa s compared with 9 Pa s), lower yield stress (2 Pa compared with 4 Pa), lower complex viscosity (13 Pa s compared with 26 Pa s), and lower apparent viscosity (0.4 Pa s compared with 1 Pa s) than the control, respectively. The yogurts with the lowest firmness and viscosity were produced with concentrates which contained the highest amount of non‐protein nitrogen fraction (160 g kg^?1 versus 126 g kg^?1 of the total nitrogen), and the highest amount of denaturation of the whey protein (262 versus 200 g kg^?1 of the total nitrogen). Copyright © 2004 Society of Chemical Industry     

高密度菌种发酵酸奶品质变化研究

为了比较高密度与非高密度两种菌种发酵的酸奶的感官性状及理化指标,对两种菌种发酵酸奶的菌落总数、pH值、黏度、稳定性、滴定酸度、保水性进行对比,并采用气相色谱-质谱（GC-MS）法对挥发性风味物质进行对比。结果表明,高密度菌种发酵制备的酸奶菌落总数（8.23～8.70 lgCFU/mL）、滴定酸度（88～92 °T）及感官评分（76～78分）分别高于非高密度菌种发酵制备的酸奶（7.98～8.53 lgCFU/mL）、（82.3～91.1 °T）、（68～70分）,而二者pH值、黏度、稳定性、保水性相差不大。高密度与非高密度菌种发酵酸奶中共检测风味化合物分别为24、20种,其中酯类物质的相对含量分别为0.52%、0.41%,酮类物质的相对含量分别为0.048%、0.012%。因此,高密度菌种发酵所得酸奶品质指标较优。     

椰子油基酸奶的品质及体外消化特性研究

为开发新型酸奶,给消费者提供更多的选择,以脱脂奶粉、水、椰子油为原料,经高速剪切、高压均质制备富含椰子油的复原乳,再经灭菌、冷却、接种、发酵后制得椰子油基酸奶。探究了椰子油添加量(0%、2%、4%、6%、8%、10%和12%)对复原乳粒径的影响,对酸奶酸度、色度、持水性、感官特性、质构特性的影响,并研究了感官得分最高的椰子油基酸奶的消化特性。结果表明：椰子油添加量在2%～8%时,复原乳的平均粒径和粒径分布均无显著性差异;椰子油添加量为6%时,酸奶感官评分最高,为89.1分,此时酸奶的持水力为87.1%、pH为4.25、色度L*为89.42;体外肠消化模拟实验证明,椰子油基酸奶(椰子油添加量为6%)的甘油三酯水解率及脂肪酸释放率分别比相同含油量的传统酸奶高25.99%及13.85%。综上,添加椰子油有利于酸奶的消化吸收,且椰子油添加量为6%时制得的酸奶整体品质最好。     

市售酸奶与传统酸奶传代发酵的比较研究

目的研究酸奶中乳酸菌群在传代发酵过程中对成品酸奶的品质影响。方法市售酸奶和传统酸奶在13%的脱脂乳中连续传代发酵10次,对酸奶的乳酸菌数和理化指标进行检测,对其凝乳状态、品质滋味进行分析评价。结果随着传代次数的增加,市售酸奶和传统酸奶的乳酸菌菌落数、持水力、总酸度值均显著增加(P0.05),pH值呈现先升高再降低的变化趋势,总体变化显著(P0.05);由感官评价结果可知,传统酸奶总酸度整体高于市售酸奶,所以口感上稍逊于市售酸奶,但其质地醇厚、香味浓郁而优于市售酸奶。结论 2种酸奶中的乳酸菌群在传代过程中没有出现衰退现象,传统酸奶随着传代次数的增加,凝乳状态、风味品质都有所提升。     

蓝靛果酒渣抗氧化膳食纤维酸奶的研制及性质分析

本研究以蓝靛果酒渣为原料,制备抗氧化性膳食纤维酸奶,并对其品质及抗氧化能力进行评价。实验结果表明:蓝靛果酒渣膳食纤维含量为63.32%,多酚含量27.01 mg/g,总黄酮含量42.82 mg/g,每克蓝靛果酒渣对DPPH自由基清除能力相当于1.89 g V_E,符合抗氧化膳食纤维标准。蓝靛果酒渣抗氧化膳食纤维酸奶的适宜工艺条件为蓝靛果酒渣1.0 g/100 g、白砂糖8 g/100 g、果胶0.1 g/100 g、脱脂奶粉1.0 g/100 g、发酵时间7 h。酒渣酸奶中多酚和黄酮的保留率分别为80.21%,84.34%。与对照酸奶相比酒渣酸奶的滴定酸度、持水率、乳清析出率、质构无显著变化(p>0.05),而酒渣酸奶对DPPH自由基清除能力、·OH自由基清除能力和总还原能力均显著高于对照酸奶(p<0.05)。蓝靛果酒渣适合作为抗氧化膳食纤维在乳品中应用。      

市售酸奶与传统酸奶传代发酵的比较研究

【目的】为了研究酸奶中乳酸菌群在传代发酵过程中对成品酸奶的品质影响,【方法】以市售酸奶和传统酸奶在13%的脱脂乳中连续传代发酵10次,对酸奶的乳酸菌数和理化指标进行检测,对其凝乳状态、品质滋味进行分析评价。【结果】随着传代次数的增加市售酸奶和传统酸奶的乳酸菌菌落数、持水力、总酸度值均显著增加(P<0.05),pH值呈现先升高再降低的变化趋势,总体变化显著(P<0.05);由感官评价结果可知,传统酸奶总酸度整体高于市售酸奶,所以口感上稍逊于市售酸奶,但其质地醇厚、香味浓郁而优于市售酸奶。【结论】两种酸奶中的乳酸菌群在传代过程中没有出现衰退现象,传统酸奶随着传代次数的增加,凝乳状态、风味品质都有所提升。