Lactose Content Research Articles

Analysis of milk adulteration by means of a potentiometric electronic tongue

The adulteration of milk presents significant challenges in the food industry, promoting the need for efficient detection methods. This study introduces a potentiometric electronic tongue for rapid and accurate milk adulteration detection. Utilizing polymeric membranes integrated with various additives, the electronic tongue distinguishes between different milk types and detects common adulterants. Experimental results demonstrate its effectiveness in discriminating raw, pasteurized, and medicated cow milk, as well as goat milk. Moreover, it successfully identifies adulterants like water and bovine milk in goat milk samples. Chemometric analyses, including Principal Component Analysis and Partial Least Squares regression, correlate sensor responses with traditional milk parameters such as fat, protein, and lactose content with up to a 0.97 R2 on the validation step. Strong correlations validate the electronic tongue's potential for rapid milk quality assessment. This innovative approach offers a cost-effective, reliable solution for detecting milk adulteration in contrast with current techniques that require numerous, time consuming experiments.

Nutritional Value and Technological Parameters of Milk From Organic and Conventional Farms in Poland

Abstract The aim of the study was to assess the nutritional value and technological parameters of milk produced in organic and conventional farming systems, taking into account the breeds of cow, feeding system, and season of production in Poland. A total of 413 milk samples were analysed, of which 220 were from Simmental cows raised on organic farms and 193 were from conventional farms, including 64 from Polish Black-and-White cows fed in a traditional system, as well as 65 from Simmental cows and 64 from Holstein-Friesian cows fed in a TMR (Total Mixed Ration) system. The milk was analysed for content of fat, protein, lactose, and urea; somatic cell count; suitability for processing (active and titratable acidity, casein content, protein-to-fat ratio, heat stability, and rennet coagulation); and content of biologically active substances (whey proteins, fatty acids, and macro- and microelements). Simmental cows from organic farms had the lowest daily milk yield, with the lowest concentrations of basic nutrients. However, it was a richer source of α-lactalbumin, lactoferrin and lysozyme and had the highest content of PUFA s. It also had a favourable protein-to-fat ratio and the shortest rennet clotting time, but it contained less Ca, Mg and Zn than milk from farms using a TMR system. The season of production had a greater influence on the composition, nutritional value and technological parameters of milk from farms using traditional feeding, including organic farms, compared to those using a TMR diet. Milk from organic farms obtained in the summer season contained more dry matter, including total protein, β-lactoglobulin, α-lactalbumin, lactoferrin, and lysozyme. It was also characterised by a more preferable fatty acid profile, i.e. lower content of SFA and higher of UFA, including MUFA and PUFA . In turn, milk from the winter season contained more fat and showed better heat stability. At farms using traditional feeding regimens, both organic and conventional, the production period had a more significant impact on the differentiation of the content of mineral components in milk (mainly macroelements).

Single droplet drying of dairy‐based systems at spray drying like temperature–time trajectories

Upon spray drying of dairy powders, the distribution of components within the droplets can become nonuniform. In this study, the influence of the composition on the drying behaviour, morphological development and surface composition were studied using single droplet drying. The addition of fat was found to result in an earlier locking point (1.1 instead of 1.8 s). The fat content did not influence the morphological development, but the protein and lactose ratios did influence whether the dried particle was smooth or wrinkled. Confocal Raman microscopy revealed that the initial fat, lactose and protein contents influenced the dry surface composition. For example, fat was found on the surface of emulsions that were either rich in fat or in whey protein.

Quality of cow’s milk as a raw material in the dairy industry from the Pelagonian region in North Macedonia

This scientific work provides a comparison and analysis of the quality and hygiene requirements of raw cow’s milk obtained from individual producers of large and small farms in three regions of Pelagonia in accordance with the Rulebook on requirements for quality, safety and hygiene of milk. The examinations include analysis of the parameters of the chemical composition, determination of the number of somatic cells and total number of bacteria from milk samples taken throughout the year from small and large farms. The best results (p<0.05) for the protein content are observed in the milk coming from small and large farms from the Southern part of the Pelagonia region, compared to the Northern part of the Pelagonia region and Prilep region. The amount of dry fat-free matter in the milk from small farms in all three regions did not show a statistically significant difference (p<0.05). The results for the lactose content of milk from all three examined regions are within the limits of the Rulebook for raw milk. A significant difference (p<0.01) was found for the content of somatic cells in small farms. It is noteworthy that small farms deviate significantly from the safety and hygiene requirements outlined in the Rulebook, primarily due to the hygiene practices concerning dairy cows. The results obtained will be valuable for the dairy industry, as they will identify weaknesses among domestic producers. Professional services will implement measures and activities to help farmers meet EU standards in milk production. Additionally, these findings will provide a significant basis for establishing strategies in this agricultural sector.

Effects of Different Seasons on Milk Quality: A Study on Two Cattle Breeds in Rainy and Drought Contexts

The primary focus of dairy farming in the central region of Peru centers on producers. However, there is limited information on how different altitudinal zones, particularly during rainy and dry seasons, affect milk production. The present study aimed to investigate the effects of the rainy and dry seasons on the physicochemical properties of milk from Brown Swiss and Holstein cattle. A total of sixty cows were selected for the study, comprising 30 Brown Swiss and 30 Holstein. The study was conducted across two distinct seasons, including rainy and dry seasons. All animals received the same semi-intensive management and were fed ryegrass and balanced feed. Each animal provided 500 ml of milk for analysis in the morning. The milk was transported at a temperature of 2 °C, where they were analyzed with the Lactoscan equipment to evaluate protein, lactose, fat, total solids, milk density, freezing point, salts, and pH. Significant differences were observed in the interaction between Brown Swiss and Holstein breeds across different seasons, including rainy and dry periods. Significant differences were observed in protein content, showing a positive effect in the interaction “rain: Brown” a value of 3.50 ± 0.36, while “rain: Holstein” showed 3.14 ± 0.05. Statistical differences were observed in the interactions for lactose content, with rain: Brown at 4.82% and dry: Holstein at 4.37%. Similarly, there were significant differences in fat content and total solids for rain interaction of rain: Holsten, and dry: Brown. Nevertheless, no differences were observed in terms of milk density, freezing point, salts, and pH. It is concluded that there was an influence of the interaction between breed physiology and seasonal conditions on milk composition. The results also highlight the impact of season-specific environmental factors on the quality of milk.

The Main Features and Microbiota Diversity of Fermented Camel Milk.

Fermented camel milk, named shubat in Central Asia, is historically and culturally important because it is mainly consumed by Kazakh people who live not only in Kazakhstan but also in close neighboring countries. However, despite its cultural and dietetic significance for this local population, research on its composition and processing technology and the richness of its microflora is relatively scarce. The present review of this product, which is an important beverage in the Kazakh culture, provides up-to-date information regarding its main components and their variability according to different factors, surveys recent changes in the processing technologies for making it using modern techniques, and explores the biodiversity of its microflora. It was reported that the protein, vitamin C, and calcium contents in shubat vary between 1.19 and 5.63%, 28 and 417 mg L-1, and 1.03 and 1.88 g L-1. The lactose content totally disappears. Shubat contains a complex microbial consortium that contributes to its strong reputation for health benefits, but a scientific demonstration of these claims has only been partially achieved.

Study of Continuous Ohmic Heating on Quality Attributes of Paneer and Its Shelf Life

The study was aimed to compare the quality attributes of paneer prepared by milk heated using a two-stage continuous ohmic heating system was compared with convectional method. The comparison was based on compositional and textural analysis of conventionally prepared paneer. The changes occurred in sensory, acidity and microbial profile during storage at refrigeration temperature was studied . Desired temperature of milk (80°C) was achieved by applying voltage of 137.7 V in stage-1 and 72.2 V in stage-2, whereas steam was used as a heating medium in conventional method. The composition of paneer was not affected significantly and showed similar values for moisture, fat, protein, lactose and ash content at par. Moreover, the values of hardness, cohesiveness, springiness and adhesiveness were slightly lower compared to samples heated using conventional methods, indicating better textural profile of ohmically prepared paneer.

Single-Cell Protein and Ethanol Production of a Newly Isolated Kluyveromyces marxianus Strain through Cheese Whey Valorization.

The present work examined the production of single-cell protein (SCP) by a newly isolated strain of Kluyveromyces marxianus EXF-5288 under increased lactose concentration of deproteinized cheese whey (DCW) and different temperatures (in °C: 20.0, 25.0, 30.0 and 35.0). To the best of the authors' knowledge, this is the first report examining the ability of Kluyveromyces marxianus species to produce SCP at T = 20.0 °C. Different culture temperatures led to significant differences in the strain's growth, while maximum biomass and SCP production (14.24 ± 0.70 and 6.14 ± 0.66 g/L, respectively) were observed in the cultivation of K. marxianus strain EXF-5288 in shake-flask cultures at T = 20.0 °C. Increased DCW lactose concentrations (35.0-100.0 g/L) led to increased ethanol production (Ethmax = 35.5 ± 0.2 g/L), suggesting that K. marxianus strain EXF-5288 is "Crabtree-positive". Batch-bioreactor trials shifted the strain's metabolism to alcoholic fermentation, favoring ethanol production. Surprisingly, K. marxianus strain EXF-5288 was able to catabolize the produced ethanol under limited carbon presence in the medium. The dominant amino acids in SCP were glutamate (15.5 mg/g), aspartic acid (12.0 mg/g) and valine (9.5 mg/g), representing a balanced nutritional profile.

Recovery of lactose from acid whey by nanofiltration: An experimental study

The flowsheet of an overall process to recover valuable products from raw acid whey is proposed. It considers typical pretreatments, an ultrafiltration step to remove proteins, a decalcification step to remove calcium and magnesium by precipitation, and a nanofiltration/diafiltration step for demineralization and deacidification of lactose. The performance of each step is evaluated and the characteristics of the main streams are estimated. The feasibility of lactose recovery after the decalcification step by nanofiltration is demonstrated by using a spiral wound module. Membrane characterization was performed at pH 4 and 50 °C, with an artificial solution containing lactose, lactic acid and sodium chloride, prepared to mimic the clarified supernatant from the decalcification unit. The feasibility of the simultaneous concentration and deacidification of lactose is finally validated by processing a real solution. With the real solution, the maximum removal of lactic acid, close to 87%, is obtained by operating with a nanofiltration (NF) step (at a concentration factor of 3.5) followed by a NF step operated in diafiltration mode (DF) at constant volume (at a dilution factor of 1.8). A lactic acid/lactose ratio of 0.018 g/g is achieved, with an overall lactose purity and yield of 93.6% and 98.2%, respectively, when operating at low pressure values (up to 12–14 bar). A preliminary process simulation is finally performed to identify the premises for process optimization of the NF+DF configuration. The success of the integrated NF+DF process is contingent upon the correct balance between the choice of the membrane and the operating conditions, which ensure lactose rejections exceeding 98.5% and lactic acid rejections falling below 20–30%, while maintaining transmembrane fluxes between 8 and 15 dm3/(hm2).

Improving the physicochemical and sensory properties and volatile profile of goat ricotta cream with Limosilactobacillus mucosae CNPC007 supplementation

This study assessed the effects of the autochthonous strain Limosilactobacillus mucosae CNPC007 on the techno-functional characteristics, physicochemical properties, volatile profile, and sensory aspects of goat ricotta cream during refrigerated storage. Three cheese formulations were tested: CRC (without probiotic), RCLM (with L. mucosae CNPC007), and RCLA (with commercial probiotic Lactobacillus acidophilus La-5). L. mucosae CNPC007 influenced color, adhesiveness, lactose content, acidity, and proteolysis depth index in goat ricotta cream. RCLA and RCLM maintained a probiotic viable cell count >6 log CFU g−1. RCLM had the highest proteolysis depth index and free amino acid release. Seventeen distinct volatile compounds were identified in the formulations. Probiotic supplementation did not affect global acceptance or purchase intention. RCLA and RCLM were preferred over CRC in the ranking test and considered ideal for goat aroma in the JAR test. L. mucosae CNPC007 supplementation has the potential to improve the nutritional, functional, aromatic, and sensory aspects of goat ricotta cream.

Presence of pathogen DNA in milk harvested from quarters is associated to changes in cows’ milk yield and composition

BackgroundIntramammary infection is the result of invasion and multiplication of microorganisms in the mammary gland and commonly leads to mastitis in dairy animals. Although much has been done to improve cows’ udder health, mastitis remains a significant and costly health issue for dairy farmers, especially if subclinical. In this study, quarter milk samples from clinically healthy cows were harvested to detect pathogens via quantitative PCR (qPCR) and evaluate changes in individual milk traits according to the number of quarters infected and the type of microorganism(s). A commercial qPCR kit was used for detection of Mycoplasma bovis, Mycoplasma spp., Staphylococcus aureus, coagulase-negative staphylococci (CNS), Streptococcus agalactiae, Streptococcus dysgalactiae, Streptococcus uberis, Prototheca spp., Escherichia coli, Klebsiella spp., Enterococcus spp. and Lactococcus lactis ssp. lactis. Quarter and pooled milk information of 383 Holstein, 132 Simmental, 129 Rendena, and 112 Jersey cows in 9 Italian single-breed herds was available.ResultsAmong the cows with pathogen(s) present in at least 1 quarter, CNS was the most commonly detected DNA, followed by Streptococcus uberis, Mycoplasma bovis, and Streptococcus agalactiae. Cows negative to qPCR were 206 and had the lowest milk somatic cell count. Viceversa, cows with DNA isolated in ≥ 3 quarters were those with the highest somatic cell count. Moreover, when major pathogens were isolated in ≥ 3 quarters, milk had the lowest casein index and lactose content. In animals with pathogen(s) DNA isolated, the extent with whom milk yield and major solids were impaired did not significantly differ between major and minor pathogens.ConclusionsThe effect of the number of affected quarters on the pool milk quality traits was investigated in clinically healthy cows using a commercial kit. Results remark the important negative effect of subclinical udder inflammations on milk yield and quality, but more efforts should be made to investigate the presence of untargeted microorganisms, as they may be potentially dangerous for cows. For a smarter use of antimicrobials, analysis of milk via qPCR is advisable – especially in cows at dry off - to identify quarters at high risk of inflammation and thus apply a targeted/tailored treatment.

Electronic tongue made of gelatin self-supporting films on printed electrodes to detect lactose

An electronic tongue was developed for the detection of lactose content in commercial foods. This was accomplished by employing optimized detection units comprised of gelatin films and information visualization methods for data analysis. The films incorporating gelatin, tannic acid, and zein, served as the basis for the sensors, whose electrodes were screen printed using carbon black ink. Self-supporting films were produced using various combinations of these materials, some of which had limited solubility in water (from 33% to 36%). They were hydrophobic and yielded reproducible electrical impedance spectra to be used as sensing units. Lactose detection experiments were conducted using various standard concentrations and commercial food samples. Capacitance decreased with lactose concentration at low frequencies, with films lacking a hydrophobic coating showing higher capacitance signals (exceeding 200 nF). Low limits of detection were obtained for the most sensitive films, as low as 2.03 × 10−19 mol/L, comparable to existing biosensors to detect lactose. Combining data from four sensing units in an electronic tongue allowed for the differentiation of lactose concentrations ranging from 1 × 10−20 mol/L to 1 × 10−6 mol/L using the interactive document mapping (IDMAP) projection technique, leading to a silhouette coefficient of 0.716. The discriminatory power of the electronic tongue was validated by distinguishing between lactose-containing and lactose-free food products. These findings highlight the potential of electronic tongues made with sustainable materials for applications in food quality assessment and lactose intolerance management.

Influence of supplemental choline on milk yield, fatty acid profile, and weight changes in postpartum ewes and their offspring.

The most intensive nutritional requirements occur during milk production's peak. Ewe milk contains more protein and fat than cow milk. The nutritional factors significantly determine the composition. The liver undergoes high stress during lactation but is relieved by essential nutrients. Choline acts metabolically as a lipotrope. This compound functions in cell structure construction, maintenance, and acetylcholine synthesis. The animal nutrition industry provides choline from various sources, such as synthetic and natural kinds. This study evaluated the influence of two distinct choline sources on dairy ewes' peripartum and postpartum milk production, composition, and offspring growth. Twenty-four Rambouillet ewes, each weighing around 63.7 ± 1.7 kg, aged three with two previous births, spent 30-day pre-partum and post-partum in individual pens (2 × 2 m). They were given different experimental treatments 30 days before and after birth according to a randomized design; no choline (a), 4 g/day rumen-protected choline (RPC) (b), or 4 g/day thiocholine (c). Milk samples for milk composition and long-chain fatty acid (FA) analysis were taken every 30 days during milk collection. Significant differences (p < 0.05) in ewe body weight, lamb birth weight, and 30-day-old lamb body weight were observed at lambing and on day 30 of lactation due to choline treatment. Milk yield was significantly higher (1.57 kg/day) compared to the control (1.02 kg/day) and RPC (1.39 kg/day), due to the herbal choline source. There was no significant difference in the milk's protein, lactose, fat, non-fat solids, and total milk solids content between the treatments. Herbal choline lowers (p < 0.05) the concentrations of caproic, caprylic, capric, lauric, and myristic acids while boosting (p < 0.05) those of oleic and cis-11-eicosenoic acid, the changes influencing long-chain FA levels (p < 0.05). Providing choline from both sources to ewes enhanced milk production and body weight at lambing and on 30-day post-lambing. The herbal choline supplement altered short-chain milk FAs, while representative concentration pathways affected medium-chain ones.

Energy and protein levels in dairy cow diets to recover milk ethanol stability

The objective of this study was to evaluate the effect of energy and protein in the diet on the recovery of milk ethanol stability (MES) induced by feed restriction. Twelve Holstein and Holstein x Jersey crossbred cows with an average of 146 ± 50 d in milk, 575.4 ± 70 kg of body weight, and 18.93 ± 5.46 kg/d of milk yield were distributed in a 3x3 Latin square design with 3 treatments and 3 experimental periods. Each experimental period lasted 24 d, comprising 3 phases: a 13-d adaptation phase (100E+100P), a 4-d induction phase for milk ethanol instability (50E+50P), and a 7-d recovery phase for MES (3 treatments). The 3 treatments during the recovery phase consisted of 3 diets aiming to meet the requirements of energy and protein (100E+100P), only energy (100E+50P), or only protein (50E+100P). The diet during the adaptation and induction phases was common for all cows. The energy and protein levels to meet each cow's requirements were based on the group average. Restriction of energy and protein reduced dry matter, crude protein, and total digestive nutrient intake for cows fed 100E+50P and 50E+100P. The lowest body weight was observed for cows fed 50E+100P, with no difference for body condition score. During the induction phase, MES "was" reduced by 9 percentage units. Cows fed 100E+100P recovered MES in the first days of the recovery phase, while 100E+50P slightly improved MES, and 50E+100P had a constant decrease in MES. Cows fed 100E+50P and 50E+100P produced, respectively, 3.6 and 5.9 kg less milk than those fed 100E+100P. The 50E+100P treatment exhibited the highest milk fat content and somatic cell score, along with the lowest milk lactose content. Protein content was higher in the 100E+100P treatment. Cows fed 50E+100P showed higher serum albumin levels compared with those on the 100E+100P treatment, not differing from the 100E+50P treatment. We concluded that the complete recovery of MES in cows with feed restrictions is possible only by supplying both the energy and protein requirements in the cows' diet. However, restricting energy intake poses a greater limitation on MES recovery compared with restricting protein.

Isolation and characterization of a β-galactosidase from Lactobacillus helveticus for industrial processing

In this study, a thermostable β-galactosidase from Lactobacillus helveticus (Lb. helveticus) OSU-PECh-4A has been isolated through diafiltration and size-exclusion chromatography. The enzyme consists of a heterodimer with a molecular mass of 110 kDa, with a small and large subunit of 36 kDa and 74 kDa, respectively. The Km and Vmax values for lactose and o-nitrophenyl-β-D-galactopyranoside (oNPG) hydrolysis were, respectively, 29.87 ± 1.05 mM, 1.88 ± 0.02 μmol D-glucose released per min per mg of protein, and 0.067 ± 0.003 mM, 1.70 ± 0.05 μmol o-nitrophenol (oNP) released per min per mg of protein. This β-galactosidase is significantly activated by Mg+2 (2–10 mM) and slightly inhibited by D-Glucose. The enzyme can also hydrolyze 57 ± 3% of lactose after 12 h of reaction at 45°C and under high lactose concentration. We propose that this enzyme provides a significant advantage from a practical and consumer point of view due to its origins as a probiotic source and improved features for important industrial applications, such as lactose hydrolysis and the potential to produce galacto-oligosaccharides (GOS).

Simultaneous production of d-allulose and d-tagatose from lactose

The high-demand rare sugars d-tagatose and d-allulose may be produced from lactose in a combined process, though this dual conversion has not yet been demonstrated. Four enzymes from thermophilic organisms were cloned and expressed in Escherichia coli to synthesize d-tagatose and d-allulose from lactose: β-galactosidase (Geobacillus stearothermophilus), l-arabinose isomerase (G. stearothermophilus US100), d-glucose isomerase (Weizmannia coagulans) and d-allulose epimerase (Arthrobacter globiformis). A single-pot reaction mixture yielded 9.9 ± 1.5 mg mL−1d-allulose and 10.7 ± 1.1 mg mL−1d-tagatose after 24 h at 70 °C. Enzyme addition order did not have an impact on yields (p = 0.3527). Higher lactose concentrations resulted in higher d-tagatose concentrations (p ≤ 0.001) regardless of when the lactose was added, however, specific yields for d-allulose were higher without adding additional lactose during the reaction (p ≤ 0.001). These experiments demonstrate that a single pot synthesis of d-tagatose and d-allulose is feasible and with more optimization could be used in industrial applications.

Kinetics and products of Thermotoga maritima β-glucosidase with lactose and cellobiose

Galacto-oligosaccharides (GOS) are prebiotic compounds that are mainly used in infant formula to mimic bifidogenic effects of mother’s milk. They are synthesized by β-galactosidase enzymes in a trans-glycosylation reaction with lactose. Many β-galactosidase enzymes from different sources have been studied, resulting in varying GOS product compositions and yields. The in vivo role of these enzymes is in lactose hydrolysis. Therefore, the best GOS yields were achieved at high lactose concentrations up to 60%wt, which require a relatively high temperature to dissolve. Some thermostable β-glucosidase enzymes from thermophilic bacteria are also capable of using lactose or para nitrophenyl-galactose as a substrate. Here, we describe the use of the β-glucosidase BglA from Thermotoga maritima for synthesis of oligosaccharides derived from lactose and cellobiose and their detailed structural characterization. Also, the BglA enzyme kinetics and yields were determined, showing highest productivity at higher lactose and cellobiose concentrations. The BglA trans-glycosylation/hydrolysis ratio was higher with 57%wt lactose than with a nearly saturated cellobiose (20%wt) solution. The yield of GOS was very high, reaching 72.1%wt GOS from lactose. Structural elucidation of the products showed mainly β(1 → 3) and β(1 → 6) elongating activity, but also some β(1 → 4) elongation was observed. The β-glucosidase BglA from T. maritima was shown to be a very versatile enzyme, producing high yields of oligosaccharides, particularly GOS from lactose.Key points• β-Glucosidase of Thermotoga maritima synthesizes GOS from lactose at very high yield.• Thermotoga maritima β-glucosidase has high activity and high thermostability.• Thermotoga maritima β-glucosidase GOS contains mainly (β1-3) and (β1-6) linkages.Graphical

Performance in dairy cows and calves with or without cow-calf contact on pasture

Interest in dairy cow-calf contact (CCC) systems is growing, yet limited research had been focused on CCC in a pasture setting. Our study aimed to evaluate the performance of pastured dairy cows and calves with or without CCC through machine milk yield and composition, cow body condition score (BCS) and body weight (BW) decrease, and calf body weight gain (BWG). We also examined calf intake of concentrates, artificially reared calves’ milk intake, and the health of both cows and calves. Conducted on a commercial dairy freestall farm and summer farm in Norway from May to August 2021, the study included twenty cow-calf pairs: 17 Norwegian Red (NRF) and three NRF × Holstein crossbreeds. They were divided into two treatments: cow-calf contact (CC, n = 10) or early separation (ES, n = 10), each with two groups of five cow-calf pairs. CC pairs had full CCC on pasture until 6 weeks postpartum and part-time contact in weeks 7 and 8 (weaning). ES pairs were separated 1–3 h after birth, kept on separate pastures with no contact between ES cows and calves. ES calves’ received daily milk allowances of 12–14 L (weeks 0–6), reduced to 8 L (week 7) and further to 4 L (week 8). From week 9, all calves were denied access to any milk (ES) or cows (CC). During weeks 0–6, CC cows had a daily machine milk yield 23.7 kg lower/cow than ES cows. The difference was likely affected by nursing and other factors (parity and inhibited milk ejection), and persisted during weaning, with CC cows delivering 8.3 kg less/cow/day in weeks 10 and 11 postpartum. Fat and protein content in machine milk showed no significant difference, while lactose content was lower in milk from CC cows than ES cows (week 5 postpartum). CC cows had a lower BW decrease compared to ES cows (CC: 913 g/day, ES: 1415 g/day from pasture day one through week 9). ES calves had an average milk intake of 10.7 L/calf/day (weeks 0–6), and consumed more concentrates than CC calves. Calves’ daily BWG did not differ between treatments in weeks 0–6 (CC: 1340 and ES: 1250 g/day) and decreased for both treatments during weaning (CC: 1050 g/day, ES: 920 g/day in weeks 6–9). Inhibited milk ejection during machine milking was a challenge in CC cows, prompting oxytocin injections to prevent mastitis. Allowing calves full CCC or providing whole milk near ad libitum can result in similar BWG and health in calves. Further research should explore strategies to enhance milk ejection in pastured CCC cows.

Influence of Kluyveromyces lactis and Enterococcus faecalis on Obtaining Lactic Acid by Cheese Whey Fermentation

Cheese whey is a byproduct of the cheese industry that causes high levels of pollution in the environment, but its high lactose content means that it can be used as a source to obtain lactic acid. In this study, two strains, one belonging to a yeast and the other one to a bacteria (Kluyveromyces lactis and Enterococcus faecalis), were isolated from cheese whey and molecularly characterized, and the optimal growth conditions were determined. Then, using proteinized and deproteinized cheese whey, batch fermentation was carried out with the strains arranged in suspension and immobilized. The consumption of lactose and the production of lactic acid were measured through Brix degrees and acidity analysis. Afterwards, the lactic acid was purified, and its yield and physical and chemical characteristics were determined. It was proven that there were differences between each of the strains; arranged in free or encapsulated cells, the proteinized and deproteinized cheese wheys, under the same purification conditions, achieved different yields, colors, and densities of lactic acid. Immobilized Enterococcus faecalis had the highest yield (50.61 ± 34.94 g/L) using the deproteinized cheese whey compared to the immobilized Kluyveromyces lactis (35.70 ± 0.15 g/L) using the proteinized cheese whey.

Study of Milk Souring Using Raman Scattering

The possibility of using Raman spectroscopy for diagnosing cow’s milk during its souring was investigated. Statistically reliable linear dependences of IR (pH) were obtained at high sensitivity. The use of the spectral range 1000-1130 cm-1 will make it possible to obtain statistically reliable linear dependences of the integral parameters of Raman scattering on the content of fat, protein and lactose in milk, as well as milk solids.