Journal of Dairy Research最新文献

This study investigated yeast diversity and physicochemical changes during the production of Kargı Tulum cheese, a traditional Turkish cheese. Samples were collected at six key stages, from raw milk to the final product, and analysed for parameters including pH, titratable acidity, dry matter, fat, salt, protein, water-soluble protein and maturation index. During ripening, pH values ranged from 3.03 ± 0.017 to 3.70 ± 0.017, while titratable acidity increased from 0.91% ± 0.16% to 3.33% ± 0.17%. Dry matter and fat content increased significantly, reaching 50.41% ± 1.56% and 33.50% ± 5.41%, respectively. Salt content ranged from 0.58% ± 0.08% to 3.03% ± 0.58%, and protein content from 3.70% ± 0.93% to 20.63% ± 1.16%. The maturation index increased from 5.54% ± 0.71% to 16.26% ± 4.35%, indicating ongoing proteolysis. A total of 42 yeast isolates were phenotypically characterized and grouped by sugar fermentation ability, growth and salt tolerance. Internal transcribed spacer region sequencing identified key yeast species, including Kazachstania unispora, Pichia fermentans, Kluyveromyces lactis, Pichia membranifaciens and Geotrichum candidum. These species play significant roles in cheese maturation, contributing to flavour and texture. The results emphasize the importance of indigenous yeast populations in traditional cheese production and offer insights for improving fermentation and ripening processes to enhance cheese quality.

The main challenge to producing a nutritionally improved milk fat composition is to increase monounsaturated fatty acids (MUFA) and decrease saturated fatty acids (SFA) without detriment to dairy product characteristics. Our aim was to determine the optimal amount of intestinally available oleic acid (via abomasal infusion) to produce higher-MUFA milk fat with satisfactory functional characteristics for ice cream. One control and four increasing doses of free fatty acids (FA) from high oleic sunflower oil (HOSFA) were infused into the abomasa of four lactating dairy cows in a changeover design with periods of 7 d. Treatments were (1) control (no FA infused), (2) HOSFA (250 g/d), (3) HOSFA (500 g/d), (4) HOSFA (750 g/d), and (5) HOSFA (1000 g/d). All treatments included meat solubles and Tween 80 as emulsifiers. Ice cream mixes were prepared with butter oil from all treatments. Samples prepared from control and 500 g/d HOSFA infusion were evaluated by a judging panel in a triangle test. Statistical analysis of results showed linear changes in most of the variables analysed as HOSFA infusion increased. For ice cream under freezing temperatures, the 500 g/d level was optimal. Sensory evaluation analysis indicated no statistical difference between ice creams prepared from the control and 500 g/d HOSFA infusion. Changes in 23 triacylglycerol fractions were statistically correlated to functional properties at 10 min of freezing. The decrease in fractions with SFA (butyrin-caprylin-palmitin, butyrin-laurin-olein, butyrin-myristin-palmitin, butyrin-palmitin-palmitin, caproin-myristin-palmitin, butyrin-palmitin-stearin, caproin-palmitin-palmitin) and the increase in dioleyl triglycerides (with butyric, lauric, myristic and palmitic acids) and triolein were some of the most highly correlated with ice cream functional properties as the result of increasing HOSFA infusion. We were able to produce an ice cream with desirable physical and organoleptic qualities, yet containing twice as much oleic acid and two-thirds as much palmitate as a control ice cream.

This study evaluated the effect of sweet whey fermented by Lactobacillus delbrueckii subsp. bulgaricus NCFB 2772, an exopolysaccharide (EPS)-producing lactic acid bacterium (LAB), on the yield and quality of Requeson, a traditional Mexican fresh cheese, further supplemented with the probiotic strain Lactobacillus casei 431. Fermentation of the whey at 42°C for 48 hours resulted in the production of 1.126 ± 0.12 mg_eq dextran/mL of EPS. The incorporation of this EPS-rich whey led to a marked (∼230%) increase in cheese yield and significantly enhanced textural properties, including greater hardness, cohesiveness and elasticity. Furthermore, L. casei 431 maintained viability above 10⁷ cfu/g throughout 21 days of refrigerated storage (4°C), with no detectable microbial contamination. Although formulations containing EPS were slightly preferred in sensory evaluations, they exhibited improved stability and retained overall acceptable sensory quality. These results highlight the potential of EPS-producing LAB and probiotics to improve the technological, nutritional and functional attributes of fresh cheese, while contributing to the valorisation of dairy by-products.

Food wastes are thought to be a substantial source of bioactive components with many functions and varying biological activities, therefore, numerous studies have been conducted on the use of these wastes to maximize their benefits. Nano-materials have been demonstrated that have higher bioavailability, functionality and effectiveness in the food systems. This study was conducted to determine how the nutritional value and quality characteristics of ice cream would be affected by the use of nano-powders made from apricot (Prunus sp.) and peach (Prunus persica L. Batsch) kernels, watermelon (Citrullus lanatus) rind and banana (Musa spp.) peel as functional additives (1%).The tested nano-waste powders significantly (P < 0.05) increased the total solids, protein, fat and ash contents distinctly with apricot kernels (AK) and peach kernels (PK). The physiochemical properties of ice cream mix and the final product were also affected with a significant increase of viscosity and overrun. Watermelon rind (WMR) and banana peel (BP) boosted the total phenolic content and diphenyl-1-picrylhydrazyl (DPPH) scavenging activity (%) as compared to the control and other wastes. The added nano-waste powders, except for BP, enhanced the meltability, microstructure properties and improved the sensory attributes of the resultant ice cream during 30 days of storage compared to control. The study recommends utilization of the tested nano fruit wastes as value added components to create innovative and higher-quality ice cream.

Dairy cow longevity affects production economy, climate footprint, and cow welfare. Based on data from the Danish Cattle Database, this research paper evaluates the relationship between early-life risk factors associated with the period before first calving and cow longevity, including data from all Danish dairy cows culled in 2019-2023. Explanatory variables for linear mixed models included calf size, twinning, and age at first calving. Information about the length of productive life (LPL) (mean: 1,074 days) and lifetime milk yield (mean: 32,088 kg energy-corrected milk) was available for 767,305 and 716,120 cows, respectively. Milk yield per day of life increased from 7 kg in cows culled during the first lactation to more than 20 kg in cows culled in their fifth or later lactations. For cows born as singletons, LPL was one month longer for cows born as large calves than for medium-sized calves, and 2 months longer than for small calves. Cows born as twins had 2 to 3 months shorter productive lives compared to cows born as singletons. For singletons, lifetime milk yield was 1,200 kg higher for large calves than for medium-sized calves, and 2,100 kg higher than for small calves. Lifetime milk yield was 1,500 to 3,500 kg lower in cows born as twins. Cows being among the third quartile of age at first calving had an estimated productive life 2.5 months longer, and a lifetime milk yield more than 2,600 kg higher than cows calving among the first quartile of age. The results from this study clearly demonstrate the importance of 'a good start'.

A systematic review and meta-analysis was undertaken to predict the effect of prepartum energy level on postpartum energy metabolism and milk production in dairy cows. In this systematic review, the criteria of PRISMA guidelines were followed: in vivo experimental evaluation of diets with different prepartum energy levels; presentation of initial, final, and/or total results; statement of treatment period including the last 21 days of the prepartum of period; and description of dry matter intake (DMI), milk production, blood parameters and feed efficiency data. A descriptive analysis was performed for better visualization of the data, and Pearson's correlation was used between the collected variables and the prepartum energy intake. The acquired data were subsequently analysed, employing a link function in a polynomial regression model. Prepartum energy intake does not influence DMI or energy balance in the postpartum phase. A higher-energy diet prepartum increased feed efficiency postpartum, accompanied by an increase in blood levels of BHB and NEFA. However, it also resulted in a decrease in milk production and blood glucose.

This research paper evaluated the effects of different concentrations of pitanga (Eugenia uniflora L.) bagasse (PB) on the chemical, technological, and sensory properties of Petit Suisse. Petit Suisse cheeses were formulated without PB (control) and with the enrichment of 0.5%, 1.0%, and 1.5% PB, respectively. The cheeses were evaluated over a 21-day storage period. PB significantly increased Petit Suisse cheeses' fibre content and yield. There was also an increase in antioxidant activity. Higher levels of PB resulted in lower hardness and greater syneresis. In rheological measurements, the cheeses showed typical behaviour of a viscoelastic solid; However, the inclusion of PB altered the casein network, making the structure softer than the control. The PB does not affect the viability of Lactococcus and Streptococcus, maintaining the probiotic character of the product. The Petit Suisse with 1% PB resulted in greater sensory acceptance. In conclusion, adding pitanga bagasse to Petit Suisse cheese has been demonstrated to provide attractive, functional characteristics and sensory properties, opening new possibilities for product development in the dairy industry.

Probiotics, defined as live microorganisms that confer health benefits when administrated in adequate amounts, including genera such as Lactobacillus, Bifidobacterium, Bacillus, Enterococcus, Escherichia, Streptococcus and the fungal strain Saccharomyces boulardii. Extensive research has demonstrated their beneficial effects, including vitamin synthesis, inhibition of pathogenic bacterial colonization, antimicrobial activity through bacteriocins and other bioactive compounds, and modulation of immune responses via secretory IgA antibodies. These attributes render probiotics promising candidates for managing antibiotic-associated colitis, post-surgical recovery and various diarrhoeal conditions. However, concerns regarding the safety of probiotics have emerged, with reports of Bacillus clausii sepsis in immunocompromised individuals and neonates, emphasizing the need for rigorous risk assessment. Similarly, postbiotic bioactive metableelites and components derived from probiotics have gained the attention of the scientific community all over the globe as potential alternatives to live probiotics. The International Scientific Association of Probiotics and Prebiotics defines postbiotics as 'a preparation of inanimate microorganisms and/or their components that confers a health benefit on the host'. Unlike probiotics, postbiotics do not require viability to exert their effects and include bioactive compounds such as short-chain fatty acids, peptides and exopolysaccharides. These molecules exhibit immunomodulatory, anti-inflammatory and antimicrobial properties, making them promising candidates for clinical applications, particularly in immunocompromised patients where live probiotics may pose risks. Despite their recognized benefits, both probiotics and postbiotics require further investigation to optimize their therapeutic potential while mitigating associated risks. This review critically evaluates the advantages, limitations and emerging applications of probiotics and postbiotics, emphasizing the necessity of rigorous scientific validation to ensure their safety and efficacy.

The pros and cons of probiotic microorganisms.

This research article aimed to evaluate the effect of a commercial nutraceutical additive in milk replacer on the health and weight gain of dairy calves during the pre-weaning phase. A total of 126 female Holstein calves were randomly assigned to two groups: a treatment group (TRT, n = 63) receiving a commercial nutraceutical additive in the milk replacer, and a control group (CON, n = 63) receiving only the milk replacer. Health assessments included clinical diagnosis, Wisconsin scores and lung ultrasonography to assess the incidence and severity of respiratory and enteric diseases, as well as the average daily gain (ADG). The TRT group showed a reduction in the number of antibiotic treatments for respiratory diseases compared to the CON group. However, calves in the TRT group exhibited greater lung consolidation scores at 75 days of age and lower odds of recovery from pulmonary lesions. No differences were observed between groups in ADG and weaning weight. Additionally, the use of the product did not reduce the incidence or severity of diarrhoea. In fact, calves in the TRT group experienced the first episode of diarrhoea earlier than those in the CON group. These findings indicate that the nutraceutical additive did not contribute to improved enteric or respiratory health. Under real farm conditions, the use of the applied nutraceutical does not consistently lead to beneficial or additive effects across health parameters. These results underscore the importance of context-specific evaluation, as well as the consideration that formulation and environmental factors can significantly influence the outcomes of such interventions.