International Dairy Journal最新文献

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Effects of different processing methods on physicochemical and microbiological properties of kefir ice cream 不同加工方法对克菲尔冰淇淋理化和微生物特性的影响

IF 3.1 3区农林科学 Q2 FOOD SCIENCE & TECHNOLOGY

International Dairy Journal

Pub Date : 2024-10-13 DOI: 10.1016/j.idairyj.2024.106111

In this study, kefir ice cream was produced using two different methods. In method 1, the ice cream mixture was incubated with kefir starter culture until a pH value of 6.1 or 5.5 was reached, and in method 2, the ice cream mixture was blended with kefir to reach a pH value of 5.5 or 6.1. Kefir ice cream produced by method 2 had a higher overrun and lower firmness than that produced by method 1. When comparisons were made based on the pH value of the ice cream mixture, kefir ice cream produced from the ice cream mixture with a pH of 6.1 instead of 5.5 had a higher overrun and melting rate and a lower firmness. The slightly higher counts on MRS agar, M17 agar, MSE agar, DSM 254 medium, and YGC agar were determined in the kefir ice cream samples produced by method 1 or produced from an ice cream mixture with a pH of 5.5. Although it is unknown if the number of bacteria on MRS agar detected in the samples, where the number was greater than 6 log cfu g⁻¹ even after 90 days of storage, are probiotics or not, kefir ice cream has the potential to be a probiotic product. In this study, it has been demonstrated that kefir ice creams with different physicochemical and microbiological properties can be produced by altering the ice cream production method and pH value of the ice cream mixture.

在这项研究中，使用了两种不同的方法制作开菲尔冰淇淋。在方法 1 中，冰淇淋混合物与开菲尔起始培养物一起培养，直到达到 6.1 或 5.5 的 pH 值；在方法 2 中，冰淇淋混合物与开菲尔混合，达到 5.5 或 6.1 的 pH 值。与方法 1 相比，用方法 2 制作的开菲尔冰淇淋具有更高的溢出率和更低的硬度。如果根据冰淇淋混合物的 pH 值进行比较，用 pH 值为 6.1 而不是 5.5 的冰淇淋混合物生产的开菲尔冰淇淋的溢出率和融化率较高，硬度较低。在 MRS 琼脂、M17 琼脂、MSE 琼脂、DSM 254 培养基和 YGC 琼脂上检测到的计数略高于用方法 1 或用 pH 值为 5.5 的冰淇淋混合物生产的开菲尔冰淇淋样品。样品中的 MRS 琼脂上检测到的细菌数量即使在储存 90 天后仍大于 6 log cfu g-1，虽然目前还不知道这些细菌是否是益生菌，但克菲尔冰淇淋有可能成为一种益生菌产品。这项研究表明，通过改变冰淇淋生产方法和冰淇淋混合物的 pH 值，可以生产出具有不同理化和微生物特性的开菲尔冰淇淋。

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引用次数: 0

Extracellular vesicles carrying significant amounts of microRNAs are present in goat milk powders 山羊奶粉中存在携带大量 microRNA 的细胞外囊泡

IF 3.1 3区农林科学 Q2 FOOD SCIENCE & TECHNOLOGY

International Dairy Journal

Pub Date : 2024-10-13 DOI: 10.1016/j.idairyj.2024.106104

Milk-derived extracellular vesicles (mEVs) play a crucial role in intercellular communication, mainly via their microRNAs, and could influence consumer health. Little is known about mEVs from goat milk powder (GMP) consumed as an alternative to bovine milk powder. mEVs were isolated from skimmed and whole GMP, using Size Exclusion Chromatography and their microRNA profiles (miRNomes) were established using RNA sequencing. We showed by nanoparticle tracking analysis that GMPs contained between 1.56,10⁹ and 6.63,10⁹ mEVs mL⁻¹ of reconstituted milk, ranging in size from 136.8 to 160.6 nm. Five major milk protein mRNAs were also detected within mEVs. The GMP miRNome was made of 351 microRNAs, sharing 89 % of known microRNAs with previously reported raw goat milk miRNome. Thus, we demonstrated that: i) mEVs of a typical morphology are present in GMPs; ii) mEVs survived the drying process; iii) their microRNA cargo is rather well protected from degradation during this process.

牛奶衍生的细胞外囊泡（mEVs）主要通过其微核糖核酸（microRNAs）在细胞间通信中发挥着重要作用，并可能影响消费者的健康。我们利用尺寸排阻色谱法从脱脂羊奶粉和全脂羊奶粉中分离出了 mEVs，并利用 RNA 测序建立了它们的 microRNA 图谱（miRNomes）。我们通过纳米粒子跟踪分析表明，GMP 含有 1.56,109 至 6.63,109 mEVs mL-1 的重组牛奶，大小从 136.8 纳米到 160.6 纳米不等。在 mEVs 中还检测到了五种主要的牛奶蛋白 mRNA。GMP miRNome 由 351 个 microRNA 组成，与之前报道的生羊奶 miRNome 共享 89% 的已知 microRNA。因此，我们证明了：i) GMP 中存在典型形态的 mEV；ii) mEV 在干燥过程中存活下来；iii) 其 microRNA 货物在此过程中受到很好的保护，不会降解。

引用次数: 0

The effect of variations in cold plasma conditions on the detoxification of Aflatoxin M1 and degradation products 冷等离子体条件的变化对黄曲霉毒素 M1 及其降解产物解毒的影响

IF 3.1 3区农林科学 Q2 FOOD SCIENCE & TECHNOLOGY

International Dairy Journal

Pub Date : 2024-10-09 DOI: 10.1016/j.idairyj.2024.106103

The aim of this study was to explore the chemical reactive species of different operating gases, and their effect on the degradation of aflatoxin M1 (AFM1) by cold plasma by measuring the reactive species concentration. Helium, at 80, 90 or 95%, was used mixed with oxygen, nitrogen and air. The efficacy of cold plasma on aflatoxin M1 (AFM1) reduction was improved when decreasing the ratio of helium in the gas mixture. The ratio of the gas mixtures changed the cold plasma chemistry believed to be due to the differences in the concentrations of the reactive species. The degradation products of AFM1 after cold plasma treatment using a helium/air gas mixture and the degradation pathway were identified by LCMS. AFM1 was oxidised by reactive species in the cold plasma to produce degradant products with, theoretically, lower toxicity than AFM1.

本研究旨在通过测量反应物的浓度，探讨不同工作气体中的化学反应物及其对冷等离子体降解黄曲霉毒素 M1（AFM1）的影响。氦气（80%、90%或 95%）与氧气、氮气和空气混合使用。当混合气体中的氦气比例降低时，冷等离子体减少黄曲霉毒素 M1（AFM1）的效果就会提高。混合气体的比例会改变冷等离子体的化学性质，这可能是由于反应物的浓度不同造成的。使用氦气/空气混合气体进行冷等离子处理后，AFM1 的降解产物及其降解途径已通过 LCMS 鉴定。AFM1 在冷等离子体中被活性物种氧化，产生理论上毒性低于 AFM1 的降解产物。

引用次数: 0

Effect of packaging technology on ripening events occurring during storage of portioned PDO Italian semi-hard cheese 包装技术对分装的 PDO 意大利半硬质奶酪储存过程中发生的成熟事件的影响

IF 3.1 3区农林科学 Q2 FOOD SCIENCE & TECHNOLOGY

International Dairy Journal

Pub Date : 2024-10-09 DOI: 10.1016/j.idairyj.2024.106109

The aim of the present study was to assess the ability of the packaging technology (vacuum, VAC, and modified atmosphere, MAP) to preserve the microbiological, physicochemical, and sensorial properties of already ripened and portioned PDO Italian semi-hard cheese during 120 days of storage at 8 °C. Results were compared with those obtained by analyzing the original not-packed cylindrical wheel stored at 8 °C (NP). Samples packed under MAP showed yeasts’ proliferation with a final count of 4.68 Log cfu g⁻¹, similar to that detected in the NP cheese wheels at 120 days of storage. In VAC samples yeasts did not proliferate, maintaining constant levels during time. Differently from the original wheels which showed a hardness increase in concomitant with a moisture loss during storage, packed samples under both VAC and MAP did not lose water preserving the original hardness of the product. At the same time, the packaging technology did not influence the proteolysis index in comparison to NP cheese. However, in MAP samples already at 30 days of storage different volatile compounds were produced in comparison with NP and VAC cheeses, suggesting that the modified atmosphere into the MAP pack promoted alternative microbial metabolisms and final products characterized by different volatile profiles. The study clearly demonstrated that the choice of packaging technology has an impact on the development of peculiar attributes of PDO cheeses, that are required by specific regulations in order to preserve their typicality and satisfy the consumers.

本研究的目的是评估包装技术（真空包装、VAC 和改良气氛包装）在 8 °C 下贮藏 120 天期间对已成熟和分装的 PDO 意大利半硬质奶酪的微生物、物理化学和感官特性的保护能力。结果与分析在 8 °C（NP）条件下储存的原始未包装圆柱形奶酪所获得的结果进行了比较。在 MAP 下包装的样品显示出酵母菌的增殖，最终计数为 4.68 Log cfu g-1，与在 NP 存放 120 天的奶酪中检测到的计数相似。在 VAC 样品中，酵母菌没有增殖，在一段时间内保持恒定水平。与原始奶酪在储存过程中水分流失导致硬度增加不同，在 VAC 和 MAP 条件下包装的样品不会失水，从而保持了产品的原始硬度。同时，与 NP 奶酪相比，包装技术对蛋白水解指数没有影响。不过，与 NP 和 VAC 奶酪相比，MAP 样品在储存 30 天后就会产生不同的挥发性化合物，这表明 MAP 包装中的改良气氛促进了其他微生物的新陈代谢，并使最终产品具有不同的挥发性特征。这项研究清楚地表明，包装技术的选择会影响到 PDO 奶酪特殊属性的发展，而这些属性是特定法规所要求的，以保持其典型性并满足消费者的需求。

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引用次数: 0

Assessment of the impact of pasteurisation on protein denaturation in sheep sweet whey by asymmetrical flow field-flow fractionation according to sampling period 通过非对称流场-流分馏法评估巴氏杀菌对绵羊甜乳清中蛋白质变性的影响

IF 3.1 3区农林科学 Q2 FOOD SCIENCE & TECHNOLOGY

International Dairy Journal

Pub Date : 2024-10-05 DOI: 10.1016/j.idairyj.2024.106105

Whey recovery is limited in artisanal cheese manufacture. This by-product of cheese manufacture was traditionally considered as waste and is highly polluting. However, interest in the nutritional properties of native whey and its proteins has recently increased. Pretreatment is required to preserve highly perishable whey for processing. Only a few studies have focused on sheep whey, despite its considerable nutritional and technological potential. Here, we investigated the effect of heat treatment on the denaturation and formation of protein aggregates in sweet sheep whey collected in January, April and July. Two pasteurisation protocols were studied (72 °C for 1 min and 80 °C for 15 s). Microbiological quality was assessed by checking for the presence of microbes after five days of storage at 4 °C. Asymmetrical flow field-flow fractionation (AF4) coupled to UV detector, multiangle light scattering (MALS) and refractometer (dRi) is a mild, non-naturing technique for determining the extent of denaturation of whey proteins and the size of whey protein aggregates. Greater whey protein denaturation and larger whey protein aggregates were observed for the 80 °C/15 s protocol than for the 72 °C/1 min protocol, for the January and April samples. A decrease in Immunoglobulin G (IgG) content was observed after heat treatments in the samples from July but not significantly for the other proteins. Moreover, the retention times of the monomeric whey protein peaks on the AF4 fractogram were higher for this period, indicating that the proteins were larger. Microbiological testing showed that both pasteurisation treatments were sufficiently effective to ensure good sanitary quality. The pasteurisation schedule best preserving native proteins was heating at 72 °C for 1 min.

在手工奶酪生产中，乳清的回收很有限。这种奶酪生产的副产品传统上被视为废物，污染严重。然而，最近人们对本地乳清及其蛋白质的营养特性越来越感兴趣。为了保存极易变质的乳清以供加工，需要对其进行预处理。尽管羊乳清具有相当大的营养和技术潜力，但只有少数研究关注羊乳清。在这里，我们研究了热处理对 1 月、4 月和 7 月收集的甜绵羊乳清中蛋白质变性和聚合体形成的影响。我们研究了两种巴氏杀菌方案（72 °C 1 分钟和 80 °C 15 秒）。在 4 °C 下储存五天后，通过检查是否存在微生物来评估微生物质量。不对称流场-流动分馏（AF4）与紫外线检测器、多角度光散射（MALS）和折射仪（dRi）相结合，是一种温和的非变性技术，用于确定乳清蛋白变性的程度和乳清蛋白聚集体的大小。在一月份和四月份的样品中，80 °C/15秒方案比72 °C/1分钟方案观察到更大的乳清蛋白变性和更大的乳清蛋白聚集。七月份的样品经热处理后，免疫球蛋白 G (IgG) 含量有所下降，但其他蛋白质的下降并不明显。此外，这一时期 AF4 分馏图上单体乳清蛋白峰的保留时间较长，表明蛋白质较大。微生物测试表明，两种巴氏杀菌处理方法都足以确保良好的卫生质量。最能保存原生蛋白质的巴氏杀菌程序是在 72 °C 下加热 1 分钟。

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引用次数: 0

Levels of three natural milk antimicrobial proteins during the manufacture of Cheddar cheese 切达奶酪生产过程中三种天然牛奶抗菌蛋白的含量

IF 3.1 3区农林科学 Q2 FOOD SCIENCE & TECHNOLOGY

International Dairy Journal

Pub Date : 2024-10-05 DOI: 10.1016/j.idairyj.2024.106106

Variations in cheese quality are explained by many factors. Among them, some influence the microbiota of cheeses such as native milk antimicrobial proteins. This project aimed to determine the concentration and activity of lactoferrin (LF), lactoperoxidase (LP) and lysozyme (LZ) during cheesemaking. Each antimicrobial protein was analyzed by two methods. An enzyme-linked immunosorbent assay (ELISA) technique was utilized to analyze each antimicrobial protein. In addition, LP was measured by spectrometry and LZ by fluorescence. Despite the lack of correlation between the results obtained by ELISA and the other methods, the measurement of LF, LP and LZ in raw milk and thermized milk showed no significant differences. The ELISA methods were selected to determine the retention of LF, LP and LZ in fresh cheese made from thermized milk. A total of 12 independent assays of cheddar cheese made commercially by a Canadian Dairy processor and at a pilot plant were evaluated. The concentration and activity of the three antimicrobial proteins were higher in cheese than in milk by an average factor of 3.5. These results allow a better understanding of the transition of the antimicrobial proteins present in milk when making cheese and to potentially, be able to control their concentration.

奶酪质量的变化是由许多因素造成的。其中，有些因素会影响奶酪的微生物群，如原生乳抗菌蛋白。本项目旨在确定奶酪制作过程中乳铁蛋白（LF）、乳过氧化物酶（LP）和溶菌酶（LZ）的浓度和活性。每种抗菌蛋白都用两种方法进行了分析。使用酶联免疫吸附试验（ELISA）技术分析每种抗菌蛋白。此外，LP 和 LZ 分别用光谱法和荧光法测量。尽管 ELISA 和其他方法得出的结果之间缺乏相关性，但生牛奶和热牛奶中 LF、LP 和 LZ 的测量结果显示没有显著差异。选择 ELISA 方法是为了确定热牛奶制成的新鲜奶酪中 LF、LP 和 LZ 的保留情况。对加拿大一家乳品加工商和一家试验工厂生产的商业切达奶酪进行了总共 12 次独立检测评估。奶酪中三种抗菌蛋白的浓度和活性比牛奶中高，平均高出 3.5 倍。这些结果使人们能够更好地了解牛奶中的抗菌蛋白在奶酪制作过程中的转变，并有可能控制它们的浓度。

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引用次数: 0

Influence of β-lactoglobulin and κ-casein genotype on whey protein denaturation in heated bovine milk and rennet whey β-乳球蛋白和κ-酪蛋白基因型对加热牛乳和凝乳酶乳清中乳清蛋白变性的影响

IF 3.1 3区农林科学 Q2 FOOD SCIENCE & TECHNOLOGY

International Dairy Journal

Pub Date : 2024-10-05 DOI: 10.1016/j.idairyj.2024.106107

Whey proteins provide nutritional and functional properties in many dairy products, and their denaturation induced by heat has drawn attention in dairy research and industry. Denatured whey proteins have functional properties that are beneficial for certain applications, such as yogurt, while uncontrolled denatured protein aggregation can impair certain processes, such as rennet coagulation. The possible effect of genetic polymorphism of β-lg and κ-CN on heat-induced denaturation of whey proteins in milk and in rennet whey was investigated in this study. No effect of κ-CN genotype on the denaturation of β-lg and α-lac was detected, while the A variant of β-lg was more heat-stable than the B variant. More denatured β-lg B was shown to interact with casein micelles to form insoluble aggregates compared to the A variant. These results may provide guidance for selection of specific milk genotypes for applications where whey protein denaturation needs to be minimised or else preferred, such as foaming and emulsification.

乳清蛋白在许多乳制品中都具有营养和功能特性，其受热变性已引起乳制品研究和工业界的关注。变性乳清蛋白具有对酸奶等某些应用有益的功能特性，而不受控制的变性蛋白聚集则会损害凝乳酶凝固等某些过程。本研究调查了β-lg和κ-CN的基因多态性对牛奶和凝乳酶乳清中乳清蛋白受热变性可能产生的影响。没有发现κ-CN基因型对β-lg和α-lac的变性有影响，而β-lg的A变体比B变体更热稳定。与 A 变体相比，更多变性的 β-lg B 与酪蛋白胶束相互作用，形成不溶性的聚集体。这些结果可为选择特定的牛奶基因型提供指导，以用于需要尽量减少乳清蛋白变性或优先选择变性的应用，如发泡和乳化。

引用次数: 0

Effect of protein polymorphisms on milk composition, coagulation properties, and protein profile in dairy sheep 蛋白质多态性对奶羊牛奶成分、凝结特性和蛋白质概况的影响

IF 3.1 3区农林科学 Q2 FOOD SCIENCE & TECHNOLOGY

International Dairy Journal

Pub Date : 2024-10-02 DOI: 10.1016/j.idairyj.2024.106102

The objective of this study was to quantify the effect of protein polymorphisms on milk composition, coagulation properties, and protein profile in dairy sheep from a New Zealand flock. A total of 470 test-day records, from 147 lactating ewes, were used in the statistical analyses. Protein polymorphisms observed in the RP-HPLC were self-named for purposes of the present study. Data were analyzed using a mixed linear model, including the fixed effects of ewe age, litter size, coat-colour, and stage of lactation, and, as a covariate, deviation from the median lambing date of the flock. The effects of protein polymorphisms were added to the model, one at a time. Protein polymorphisms were significantly (p < 0.05) associated with milk composition and protein profile. Polymorphisms of β-lactoglobulin were significantly associated with milk heat stability, being AB type more heat stable than AA. The other processability traits were not significantly affected by protein polymorphisms. Further studies are required to confirm the protein variants and the properties of individual protein polymorphisms.

本研究的目的是量化蛋白质多态性对新西兰羊群中奶羊的牛奶成分、凝结特性和蛋白质概况的影响。统计分析共使用了 147 只泌乳母羊的 470 个测试日记录。在 RP-HPLC 中观察到的蛋白质多态性在本研究中自行命名。数据采用混合线性模型进行分析，其中包括母羊年龄、产仔数、被毛颜色和泌乳阶段的固定效应，以及作为协变量的羊群产羔日期中位数偏差。蛋白质多态性的影响被逐一加入到模型中。蛋白质多态性与牛奶成分和蛋白质谱有显著相关性（p < 0.05）。β-乳球蛋白的多态性与牛奶的热稳定性显著相关，AB 型比 AA 型更热稳定性。蛋白质多态性对其他加工性能没有明显影响。要确认蛋白质变体和单个蛋白质多态性的特性，还需要进一步的研究。

引用次数: 0

The single-step operation for enzyme-modified cheese production: Influence and importance of process parameters 酶改性奶酪生产的单步操作：工艺参数的影响和重要性

IF 3.1 3区农林科学 Q2 FOOD SCIENCE & TECHNOLOGY

International Dairy Journal

Pub Date : 2024-09-27 DOI: 10.1016/j.idairyj.2024.106101

Enzyme-modified cheeses (EMCs) are natural flavour ingredients with intense cheese flavour. This study utilized a single-step process to produce an EMC; a single step process offers benefits such as shorter processing time, reduced equipment needs, and lower costs. However, product development and optimization are challenging due to multiple influencing factors. The study investigated incubation parameters (temperature, time, agitation speed), enzyme concentrations (proteolytic and lipolytic ratios), and homogenisation pressures to determine the important factors. The proteolytic ripening parameters, free fatty acid profiles, and volatile compounds of EMCs were examined. Key findings indicate that incubation conditions and protease concentration significantly influence EMC properties. Proteolytic enzyme concentration and incubation time were the main contributors to proteolytic ripening, while lipolytic ripening was primarily influenced by incubation temperature and agitation speed. Notably, incubation temperature was the most critical factor affecting the variation of volatile compounds in EMC production.

酶改性奶酪（EMC）是一种具有浓郁奶酪风味的天然风味配料。本研究采用单步工艺生产 EMC；单步工艺具有加工时间短、设备需求少和成本低等优点。然而，由于影响因素众多，产品开发和优化具有挑战性。本研究调查了培养参数（温度、时间、搅拌速度）、酶浓度（蛋白分解和脂肪分解比率）和均质压力，以确定重要因素。研究还考察了 EMC 的蛋白分解成熟参数、游离脂肪酸概况和挥发性化合物。主要研究结果表明，培养条件和蛋白酶浓度对 EMC 的特性有重大影响。蛋白水解酶浓度和培养时间是蛋白水解成熟的主要因素，而脂肪水解成熟主要受培养温度和搅拌速度的影响。值得注意的是，培养温度是影响 EMC 生产中挥发性化合物变化的最关键因素。

引用次数: 0

Influence of different genotype combinations of β-lactoglobulin and β-casein in cow milk on physicochemical and sensory properties of stirred yoghurt 牛奶中β-乳球蛋白和β-酪蛋白不同基因型组合对搅拌酸奶理化和感官特性的影响

IF 3.1 3区农林科学 Q2 FOOD SCIENCE & TECHNOLOGY

International Dairy Journal

Pub Date : 2024-09-26 DOI: 10.1016/j.idairyj.2024.106099

In this study, stirred yoghurts were produced from Turkish Holstein cow milk with different genotype combinations of β-lactoglobulin and β-casein. The distribution of AA, AB, and BB genotypes of β-lactoglobulin and A1A1, A1A2, and A2A2 genotypes of β-casein was determined in a total of 135 cow milk samples. Raw cow milk samples containing AA genotype of β-LG exhibited higher non-fat total solids, protein, and fat contents in comparison to milk containing AB and BB genotypes of β-LG. Compared to the samples made from milk with other β-LG genotypes, the stirred yoghurt made from milk with β-LG AA genotype showed lower degree of syneresis and higher for hardness, apparent viscosity, and consistency coefficient. The lowest number of grains, the perimeter of grains, and the visual roughness values were obtained in the stirred yoghurts made from milk with BB genotype of β-LG and A2A2 genotype of β-CN. The sensory analysis revealed that β-CN genotypes of milk significantly influenced the overall acceptability scores of the stirred yoghurts, while β-LG genotypes did not significantly influence these scores except for the visual grainy score. The findings of this study showed that the selection of specific milk protein genotypes resulted in substantial differences in the physicochemical and sensory properties of stirred yoghurt.

本研究用土耳其荷斯坦牛乳生产了搅拌酸奶，其中含有不同基因型组合的β-乳球蛋白和β-酪蛋白。在总共 135 份牛奶样本中，测定了 β-乳球蛋白的 AA、AB 和 BB 基因型以及 β-酪蛋白的 A1A1、A1A2 和 A2A2 基因型的分布情况。与含有 AB 和 BB 基因型 β-LG 的牛奶相比，含有 AA 基因型 β-LG 的生牛奶样品的非脂总固体、蛋白质和脂肪含量更高。与用β-LG 其他基因型的牛奶制成的样品相比，用β-LG AA 基因型的牛奶制成的搅拌酸奶的粘滞度较低，硬度、表观粘度和稠度系数较高。用基因型为 β-LG 的 BB 型牛奶和基因型为 β-CN 的 A2A2 型牛奶制成的搅拌型酸奶的颗粒数、颗粒周长和视觉粗糙度值最低。感官分析表明，牛奶的 β-CN 基因型对搅拌酸奶的总体可接受性评分有显著影响，而 β-LG 基因型除视觉颗粒感评分外，对这些评分没有显著影响。这项研究的结果表明，选择特定的牛奶蛋白基因型会导致搅拌酸奶的理化和感官特性产生巨大差异。

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