Lactose Solution Research Articles

Bovine Highly Pathogenic Avian Influenza Virus Stability and Inactivation in the Milk Byproduct Lactose.

The recent incursion of highly pathogenic influenza viruses into dairy cattle opens new insights for influenza virus ecology and its interspecies transmission and may have a significant impact on public health and agriculture. The aim of this study was to determine the stability of a bovine highly pathogenic avian influenza H5N1 virus isolate in the milk byproduct lactose and to evaluate two inactivation methods using industrial procedures. The bovine isolate of the highly pathogenic avian influenza H5N1 virus was stable for 14 days in a concentrated lactose solution under refrigerated conditions. Heat or citric acid treatments successfully inactivated the virus in lactose. This study highlights the persistence of HPAIV in lactose and its efficient inactivation under industrial standards.

Bovine highly pathogenic avian influenza virus stability and inactivation in the milk byproduct lactose.

A bovine isolate of highly pathogenic avian influenza H5N1 virus was stable for 14 days in a concentrated lactose solution at under refrigerated conditions. Heat or citric acid treatments successfully inactivated viruses in lactose. This study highlights the persistence of HPAIV in lactose and its efficient inactivation under industrial standards.

Разработка технологии получения безлактозного молока методом диафильтрации

Abstract. The purpose. The research is aimed at solving the problem related to the development of technology for producing an environmentally friendly product of animal origin – lactose-free milk. This will solve the problem of consumption of milk and dairy products by people who do not tolerate milk sugar for physiological reasons. Analyzing, on the basis of a literary review, the current state of the issue of lactose-free milk production, it can be concluded that existing technologies have certain disadvantages due to changes in the composition of the initial product, or the significant complexity of the technological chain. The proposed development is based on a method of milk diafiltration consisting of several repetitive cycles. The cycle consists in the separation of milk by the ultrafiltration process into permeate (aqueous lactose solution) and concentrate (proteins, fat, lactose residues). Then pure water is added to the concentrate in a volume equal to the volume of the discharged permeate. For a scientifically based approach to the development of the proposed technology, it is necessary to conduct a study of ultrafiltration separation of milk, obtain optimal operating parameters of the process, determine the change in permeability and selectivity of membranes from lactose concentration, consider the possibility of obtaining lactose-free milk with different mass fraction of fat, determine the number of cycles of the membrane diafiltration process. Research methods. The study of the process of ultrafiltration separation of milk was carried out in laboratory conditions on a membrane installation using organic and inorganic membranes. The experiments determined the main characteristics of ultrafiltration membranes – permeability and selectivity, with varying parameters (parameter range: P = 0.15…0.5 MPa, t = 35…65 °C). Results. Based on the experimental data obtained, by processing them and optimizing the parameters, optimal modes of the milk separation process by ultrafiltration were obtained. The following parameters are defined: the velocity of the product in the supramembrane space, the operating pressure of the separation process, its temperature. The preferred ultrafiltration membranes for the membrane-milk system have been selected. Scientific novelty. To develop a technology for producing lactose-free milk, for the first time a number of studies and experiments were carried out, such as changing the permeability and selectivity of membranes from the concentration of lactose, obtaining lactose-free milk with mass fraction of fat the number of cycles of the membrane diafiltration process was determined.

Grafted calcium pectinate-whey protein isolate covalent immobilizers: Optimization, kinetics, thermodynamics, and application

Whey protein isolate (WPI) was incorporated within calcium pectinate (CPT) beads in order to boost their anionic qualities and meliorate their glutaraldehyde (GA)-polyethyleneimine (PEI) grafting process. The Box-Behnken Design (BBD) verified that WPI inclusion significantly raised the GA-PEI-CPT-WPI beads immobilized β-D-galactosidase (iβ-GLD) activity. The BBD also revealed the optimal settings for WPI concentration, PEI pH, PEI concentration, and GA concentration, which were 2.91 %, 10.8, 3.5 %, and 2.24 %, respectively. The GA-PEI-CPT-WPI beads grafting process was scrutinized via FTIR, EDX, and SEM. The optimal GA-PEI-CPT-WPI immobilizers provided fine β-GLD immobilization efficiencies, which reached up to 65.28 %. The free and GA-PEI-CPT-WPI iβ-GLDs pH and temperature profiles were scrutinized. It was also unveiled that the thermal stability of the iβ-GLD surpassed that of its free compeer as it provided lesser kd and ΔS values and larger t1/2, D-values, Ed, ΔH, and ΔG values. Furthermore, the iβ-GLD provided 92.00±3.39 % activity after 42 storage days, which denoted its fine storage stability. The iβ-GLD short duration (15 min) operational stability was also inspected, and 82.70±0.78 % activity was provided during the fifteenth degradation run. Moreover, the iβ-GLD long duration (24 h) operational stability was inspected while degrading the lactose of buffered lactose solution (BLS) and cheese whey (CW). It was unveiled that 81.86±0.96 % and 73.58±2.24 % of the initial glucose were detected during the sixth degradation runs, respectively.

Designing Centrifugal Membrane Filters with uniform-pressure for UF/NF/RO separations

A novel Ortho-Centrifugal Membrane Filter (O-CMF) was designed and assessed to tackle common issues in conventional laboratory centrifugal membrane filters, e.g. non-uniform transmembrane pressure and concentration polarization, and to ease membrane replacement. The O-CMF, manufactured by additive 3D printing in acrylonitrile butadiene styrene, with membrane area of 0.95 cm2, was designed to process a maximum liquid sample of 9 mL. It was tested with nanofiltration of aqueous solutions of NaCl, MgSO4, and lactose (concentrations of 1–20 g/L) at transmembrane pressures of 6–24 bar. Complementary Computational Fluid Dynamics (CFD) simulations, employing a custom solver from the open-source OpenFOAM-2306 c++ toolbox, were also run to seek insight of the O-CMF main features.The permeation experiments displayed minimal impact of concentration polarization. CFD simulations showed that concentration polarization is nearly uniform and that concentrate chamber is homogenized by centrifugal convection. The CFD permeate flux predictions, based on the osmotic pressure model, closely matched experimental data, and a correlation for predicting concentration polarization was also developed.The O-CMF device represents a substantial breakthrough in the technology of centrifugal membrane filters, consistently maintaining uniform transmembrane pressure and effectively minimizing concentration polarization. The device was evaluated using nanofiltration, but its pressure range is versatile enough to cover conditions suitable for both ultrafiltration and reverse osmosis operations. This adaptability extends its application across a variety of laboratory experiments, including sample concentration, hydraulic permeability tests, and membrane screening.

Hubungan Lingkungan Sosial, Pengetahuan Ibu, Dan Status Gizi Terhadap Produksi ASI Pada Ibu Nifas Di Rumah Sakit Firdaus Jakarta Utara

Introduction: Mother's Milk (ASI) is an emulsion of fat in a solution of protein, lactose, and inorganic salts secreted by the mother's mammary glands and is useful as baby food. Breast milk production is the process of forming breast milk which involves the hormone prolactin and the hormone oxytocin. The purpose of this study was to determine the relationship between social environment, mother's knowledge, and nutritional status on breast milk production in post-partum mothers at Firdaus Hospital, North Jakarta in 2023. Methods: The design of this study was an analytic descriptive quantitative method with a cross-sectional approach with a total sample of 52 mothers. Post-partum who conducted an examination at Firdaus Hospital, North Jakarta. Results: The results of the chi-square statistical test showed that there was a relationship between social environment (p-value 0,011); mother's knowledge (p-value 0,011) and nutritional status (p-value 0,000) with milk production in post-partum mothers. Discussion: The conclusion in this study is that there is a significant relationship between the social environment, mother's knowledge and nutritional status on the production of breast milk in post-partum mothers at Firdaus Hospital, North Jakarta in 2023. Suggestions for post-partum mothers to be able to improve their nutritional fulfillment during the breastfeeding period by implementing good and correct eating patterns in accordance with the nutritional adequacy rates recommended by health workers.

Optimizing semen cryopreservation in Calomys laucha: a step forward in rodent reproductive research

BACKGROUND: Examining semen cryopreservation in Calomys laucha offers valuable insights for reproductive research and species conservation. OBJECTIVE: To determine the most effective sugar for the cryopreservation of C. laucha semen. MATERIALS AND METHODS: Using 36 epididymides from C. laucha, semen samples were diluted in a 3% skimmed milk medium supplemented with one of four sugars (glucose, fructose, lactose, or sucrose) at a concentration of 0.3 M. These mixtures underwent a conditioning phase at 37°C for 10 min, cooled to −80°C for another 10 min, and were subsequently stored in liquid nitrogen. RESULTS: Upon thawing, samples treated with lactose and glucose solutions show superior sperm motility, achieving 8.2% and 10.0% respectively, in contrast to the fructose (2.0%) and sucrose (4.1%) mixtures. Furthermore, samples preserved in glucose registered the highest sperm penetration rates, reaching 44.9%. CONCLUSION: Our findings suggest that a cryopreservation medium containing 0.3 M glucose can contribute to the safeguarding C. laucha rodent semen.

Effectiveness of breast acupressure towards increasing breastmilk production in postpartum mothers

Breast Milk is an emulsion of fat in a solution of protein, lactose and inorganic salts secreted by the mammary glands which is useful as baby food. According to the 2019 Indonesian Health Demographic Survey, the achievement of exclusive breastfeeding in Indonesia was 61.33%, but not all babies were breastfed on the first day until the third day. Efforts to increase breast milk production can be done through pharmacology and non-pharmacological therapies. Pharmacological therapy can be performed by consuming breast-feeding drugs, non-pharmacological therapy can be performed by providing breast acupressure. This study aim to find out the intervention procedures, the benefits of breast acupressure intervention on the increase in breast milk production. This was a systematic literature review. Literature searching conducted for articles used electronic databases of Science Direct, Pubmed, Google Scholar, and Scopus. Articles that met the inclusion criteria were further analyzed systematically. Based on the systematic review on 10 selected article, it was explained that breast acupressure could help increase breast milk production among postpartum women. Breast acupressure could help increase breast milk production among postpartum women.

Selective anomer crystallization from aqueous solution: Monitoring lactose recovery under mutarotation limitation via attenuated total reflection Fourier-transform spectroscopy and theoretical rate analysis

Lactose is typically produced via cooling crystallization either from whey or whey permeate (edible grade) or from aqueous solution (pharmaceutical grade). While in solution, lactose is present in 2 anomeric forms, α- and β-lactose. During cooling crystallization under standard process conditions, only α-lactose crystallizes, depleting the solution of α-anomer. In practice, mutarotation kinetics are often assumed to be much faster than crystallization. However, some literature reports limitation of crystallization by mutarotation. In the present research, we investigate the influence of operating conditions on mutarotation in lactose crystallization and explore the existence of an operation regimen where mutarotation can be disregarded in the crystallization process. Therefore, we study crystallization from aqueous lactose solutions by inline monitoring of concentrations of α- and β-lactose via attenuated total reflection Fourier-transform spectroscopy. By implementing a linear cooling profile of 9 K/h to a minimum temperature of 10°C, we measured a remarkable increase in β/α ratio, reaching a maximum of 2.19. This ratio exceeds the equilibrium level by 36%. However, when the same cooling profile was applied to a minimum temperature of 25°C, the deviation was significantly lower, with a maximum β/α ratio of 1.72, representing only an 8% deviation from equilibrium. We also performed a theoretical assessment of the influence of process parameters on crystallization kinetics. We conclude that mutarotation needs to be taken into consideration for efficient crystallization control if the crystal surface area and supersaturation are sufficiently high.

Sodium Chloride versus Lactose as a Carrier for House Dust Mite Allergen in Allergen Chamber Studies: A Clinical Study to Assess Noninferiority

Introduction: In the Fraunhofer allergen challenge chamber (ACC), a standardized, universal, good manufacturing practice-conforming technology using a spray dried solution of lactose (L) and allergen extract has been established. In this study, we investigated the noninferiority of hypertonic sodium chloride (S) versus L as a carrier for house dust mite (HDM) allergen to simplify manufacturing, reduce costs, and allow for wider use. Methods: Using a participant-blinded, sham exposure-controlled, single-arm, sequential intervention study, we challenged adults with HDM allergic rhinitis five times in the ACC. Participants were first exposed to S, L, and clean air (block 1), followed by S + HDM and L + HDM (block 2). Primary endpoints were mean total nasal symptom score (TNSS) and mean nasal secretion weight. Results: 19 participants were enrolled in the study (10 females; mean age 32 years [22–49], 4 with mild allergic asthma). The safety profile of S + HDM and L + HDM was similar; eight participants experienced mild procedure-related adverse events including tiredness, cough, and dyspnea. Due to dropouts, 13 participants completed the study and were evaluated. Mean TNSS and nasal secretion were as follows: S 0.98, 0.28 g; L 1.1, 0.20 g; clean air 1.1, 0.23 g; S + HDM 5.7, 4.8 g; L + HDM 5.1, 5.1 g. Separate block 1/block 2 MANOVAs with TNSS and nasal secretion as dependent variables revealed no significant differences between the carriers, neither alone and compared with clean air (p = 0.2059, Wilk’s λ = 0.78) nor combined with HDM (p = 0.3474, Wilk’s λ = 0.89). Noninferiority of S was established using a meta-analysis-based minimal clinical important difference of −0.55: mean TNSS difference between S + HDM and L + HDM was 0.62 (90% CI: −0.51 to 1.74). Conclusion: S as an HDM carrier was safe and well tolerated. It was noninferior to L which makes it an adequate and easy-to-use carrier substitute.

Recovery of lactose from simulated delactosed whey permeate by a low-temperature crystallization process

Delactosed whey permeate is the mother liquor/by-product of lactose manufacture, but it still contains around 20 wt% lactose. The high mineral content, stickiness, and hygroscopic behavior prevent further recovery of lactose in the manufacturing process. Therefore, its use is currently limited to low-value applications such as cattle feed, and more often it is seen as waste. This study investigates a new separation technique operating at sub-zero conditions. At low temperature, precipitation of calcium phosphate is expected to be reduced and the lower solubility at sub-zero temperature makes it possible to recover a large portion of the lactose. We found that lactose could be crystallized at sub-zero conditions. The crystals had a tomahawk morphology and an average size of 23 and 31 µm. In the first 24 h, the amount of calcium phosphate precipitated was limited, whereas the lactose concentration was already close to saturation. The overall rate of crystallization was increased compared with the crystals recovered from a pure lactose solution. Mutarotation was rate limiting in the pure system but it did not limit the crystallization of lactose from delactosed whey permeate. This resulted in faster crystallization; after 24 h the yield was 85%.

Optical bi-enzyme-titania biosensor system: A new way to detect lactose

Lactose concentration is a key parameter for assessing the quality of raw and processed milk and identifying abnormal milk. Current methods for lactose determination are laborious, time-consuming and oftentimes require skilled lab workers, expensive equipment, and special reagents. In this study, an optical biosensor system based on nanosized titanium dioxide (TiO2) is presented for routine measurement of lactose in milk without sample preparation. TiO2 was obtained via sol-gel synthesis and characterized using dynamic light scattering, microelectrophoresis, X-ray diffraction, transmission electron microscopy, and nitrogen adsorption-desorption analysis. The system, whose colorimetric response was based on the chromogen-free TiO2-based detection of hydrogen peroxide (H2O2), used β-galactosidase and/or glucose oxidase as the biorecognition elements. The selectivity and sensitivity of the biosensors for lactose and glucose was investigated by diffuse reflectance spectroscopy using standard aqueous lactose and glucose solutions and whole milk samples. The results showed that the proposed biosensors had high optical signal reproducibility (RSD = 5–6%), high sensitivity (LOD = 0.005 wt%), and high selectivity. The linear dynamic ranges of lactose and glucose detection were from 0.005 wt% to 0.100 wt%, and the optimal response time of the biosensor was 25 min. The listed features and advantages of label-free detection make the biosensor attractive for simple, inexpensive, sensitive, and selective determination of lactose in milk.

Effect of composition and total solids content of dairy samples on acoustic transmission and impedance signals

Laboratory scale experiments were carried out under static conditions using an acoustic flowmeter to investigate the effect of composition and total solids (TS) content of dairy samples on acoustic transmission (AT) and acoustic impedance (AI). Dairy samples studied included skim milk (4–40% TS), whole milk (4–40% TS), milk protein concentrate samples (4–20% TS) and lactose solutions (4–20% TS).This study demonstrated that AT and AI are influenced by the composition of dairy samples. Linear and non-linear concentrate-specific regression models were developed (R2 > 0.93) using AT to predict the apparent viscosity and AI to predict the TS content of dairy samples. One non-linear model (R2 > 0.99) was sufficient to predict dairy sample density for all concentrates investigated. This study developed a new emerging process analytical technology tool that demonstrated the potential to provide new product and process insights in dairy processing as well as facilitate process efficiencies and consistent final product quality.

Glutaraldehyde-copper gelled chitosan beads: Characterization and utilization as covalent immobilizers

The robust chitosan (CHS)–Cu2+ interactions were utilized to prepare CHS beads. Glutaraldehyde (GA) was also added to the gelling medium to provide the functional entities needed for β-d-galactosidase (βG) covalent immobilization. The preparation of the GA-Cu-CHS beads was honed with respect to the concentrations of the utilized CuSO4, CHS, and GA solutions. A CHS concentration of 2% was favored. The optimal gelling medium comprised 0.2% CuSO4-1.12% GA. The beads were characterized via SEM and EDX. The beads enhanced mechanical traits were verified. The GA-Cu-CHS beads immobilized βG, and the immobilization efficiency reached 47.67% when 2.56 Ug−1 βG loading activity was adopted. The immobilized βG (iβG) experienced an acidic shift in its optimal pH range from 4.4 to 5.5 to 3.6–4.4. Moreover, its optimal temperature was slightly shifted following immobilization from 55-60 °C–60 °C. The Km and Vmax values of βG were reduced from 84.4 mM to 19.0 μmol/min mg enzyme to 64.9 mM and 5.6 μmol/min mg enzyme following immobilization. The operational stability of iβG was also studied while performing the 15 min lactose hydrolytic reaction at 37 °C, and 81.79% activity was obtained throughout the 15th hydrolytic cycle. Moreover, the iβG provided 97.30% activity after 77 days of storage in distilled water in the fridge. Finally, the iβG was utilized to degrade lactose in cheese whey and also in buffered lactose solution (BLS) at 45 °C and at pH 4.4. Each degradation cycle lasted 24 h and 78.52% of the inceptive released glucose was released during the BLS 5th degradation cycle.

Protective influence of heat treatment on the light-induced riboflavin (vitamin B2) degradation in dairy products

Milk is the most important source of riboflavin (Vitamin B2) in many nations. Riboflavin absorbs light in the ultraviolet region and generates singlet oxygen in milk leading to the oxidation of nutrient components and affects the sensory quality of dairy products. The purpose of this work was to elucidate the effect of heat-treatment on the light-induced riboflavin degradation in the model solution of milk bases and milk samples. Although the photo-degradation of riboflavin in all samples was decreased with the increasing of illumination time, the reductions of riboflavin light oxidation were found in all milk model samples and heated milks in according to the formation of Maillard reaction products during heating. The amount of riboflavin remained in control sample (1.5 mg/l riboflavin) was 1.67 % after 2.5 hour illumination. But, it was 34 % and 60 % in the heated lactose and casein solution and milk at 120oC, 45 min, respectively. The increasing of heating time leaded to the increasing of protective ability of milk and model samples against riboflavin photo-degradation. The study clarified that heat treatment of whey proteins, casein and milk might induce the formation of Maillard reaction products that enhanced the protective ability against photo-degradation of riboflavin.

Fourier transform infrared spectroscopy analysis of Lactose hydrolysis by beta-galactosidase from Lactiplantibacillus plantarum GV54 and Lactiplantibacillus sp. GV66

Introduction and Aim: The enzyme beta-galactosidase is extremely important in the food and pharmaceutical industries. The goal of this work was to improve the lactose hydrolysis process employing beta-galactosidase to convert glucose and galactose for alleviating lactose intolerance. Methods: Intracellular beta-galactosidase was extracted from Lactiplantibacillus spp. (GV54 and GV66) by cell permeabilized method using toluene/acetone solvents. Lactose hydrolysis was performed using 50 g/L of lactose with partially purified beta-galactosidase enzyme at different time intervals 2, 4, 6 and 12 h. Fourier transforms infrared spectroscopy (FTIR) was used to evaluate the degree of hydrolysis at different time intervals and lactose hydrolysis was high at 6 h of incubation. Results: The FTIR peak of lactose molecules hydrolysis by beta-galactosidase (GV54 and GV66) with different time intervals (2h, 4h, 6h, and 12h) indicates similarities in bond lengths and vibrational modes. The amide I group of beta-galactosidase is uniformly bound to lactose at 1634 per cm and C-H group of glucose and galactose was observed at 1386 per cm. In the range of 2000-800 per cm, we could identify variations in the shape and strength of these peaks, compared with control (lactose solution). Conclusion: The precise and direct measurement of individual carbohydrates such as glucose and galactose in lactose solution hydrolyzed by beta-galactosidase enzyme was successfully accomplished using FTIR spectrometry. Comparing FTIR analysis to traditional procedures, the time required is drastically decreased. These findings have the analytical power to follow the dynamics of in vitro enzymatic activity of naturally occurring substrates rich in natural carbohydrate polymers.

Determination of native lactoferrin and other whey proteins at different pH conditions after UHT using reverse phase HPLC

Whey proteins such as lactoferrin are high value components in milk; however, under UHT conditions they can denature and lose their functionality and bioactivity. The heat stability of these proteins in water suspensions was investigated at different pH conditions using a pilot scale UHT plant. An RP-HPLC method was used to quantify β-lactoglobulin, α-lactalbumin and lactoferrin simultaneously. In a pH 3.0–5.0 lactoferrin-in-water suspension, at least 48% of undenatured lactoferrin remained after UHT. The highest level of undenatured lactoferrin was 81%, observed at pH 4.0; the iron binding capacity for this sample was 78%. In addition, mixtures of whey protein concentrate and lactoferrin in a lactose solution were investigated, which showed 84% and 70% nativity for whey at pH 3.0 and pH 3.5, respectively, and 78% nativity for lactoferrin at pH 3.5. These results provide useful information in product research and development to maintain bioactive protein nativity through UHT processing.

Quantitation of trace protein in lactose for injection using SensiNanoOrange fluorescence assay

Lactose is an important pharmaceutical excipient in the drug industry. Residual protein in lactose derived from cow milk can cause acute allergic reactions in some patients, especially when lactose-containing drugs are administered via the intravenous route. The aim of this study was to develop an accurate and reliable method for quantitating trace amount of residual protein in lactose using simple instrumentation. In this work, we developed a new method called SensiNanoOrange that is based on the NanoOrange protein quantitation assay. 1. Compared with the original NanoOrange method, the sample volume was increased from ≤4% to 90% in the final test solution. 2. Using the SensiNanoOrange method, the sensitivity of the test was significantly improved. In this work, an LOQ of 0.6 μg/mL in sample solution was achieved, which is 4.2 times lower than the value reported in the original NanoOrange protocol. The calibration curve was linear from 0.5 to 5 μg/mL. 3. The accuracy and precision of the method for quantitation of protein in lactose solution were confirmed. The results showed that for the accuracy test, all recovery values ranged from 81.45 to 100.85% with RSD ≤ 11.33% in each group. The RSD for the precision test was less than 10.08%. 4. The SensiNanoOrange method was used to indicate that treatment by activated carbon can remarkably reduce the protein content in lactose solution. Our data suggested that this method is not only highly suitable for the characterization of lactose used for injections in the pharmaceutical industry but also may be useful for other biochemical and clinical applications.

Heat treatment and homogenization of bovine milk loosened gastric curd structure and increased gastric emptying in growing pigs

During gastric digestion, bovine milk forms a curd, which consists largely of proteins and lipids. However, it is unknown how processing-induced changes to curd structure affects the gastric emptying of milk proteins and lipids. This study aimed to determine the impact of heat treatment and homogenization on gastric curd formation, and gastric emptying of dry matter (DM), proteins and lipids from bovine milk fed to pigs as a human model. Growing pigs (n = 180, mean ± standard error of the mean (SEM) bodyweight 22.4 ± 0.13 kg) consumed raw, or pasteurized non-homogenized (PNH), or pasteurized homogenized (PH), or ultra-high temperature treated homogenized (UHT) milk diets. A protein-lipid-free lactose (PLFL) solution was also fed as a test diet. At 0, 20, 60, 120, 180 and 300 min postprandially the entire gastrointestinal tract was dissected out. The gastric chyme (curd and liquid) fractions were collected after separation using a mesh screen. The DM, protein, and lipid contents of these fractions were quantified. Confocal, transmission electron microscopy, cryo-scanning electron microscopy and rheological analyses were conducted to determine the micro- and macrostructure of the curd. Overall, both heat treatment and homogenization influenced the in vivo gastric curd structure formed of bovine milk, although to different extents. The gastric emptying of DM, proteins, and lipids increased with the extent of processing. Gastric emptying rates of DM and proteins followed the pattern UHT > PH > PNH = raw, while emptying rates of lipid also differed between PNH and raw milk. Curd structure was the main gastric parameter affected in PNH milk.

Role of dairy proteins in the reduction of capsaicin-induced oral burning pain

Capsaicin-induced burning sensation in the oral mucosa can be relieved by skimmed and whole milk. The mechanism behind this effect, however, is unknown. This study aimed to asses the role of milk proteins in reducing capsaicin-induced oral burning sensation. 24 healthy participants were included in this single-blinded cross-over study consisting of four sessions. In each sessions, mucosal burning sensation was evoked by having the participants dip their tongues in a cup containing 0.1% capsaicin gel for a total of 8 min. The perceived levels of unpleasantness and burning intensity were scored on two different numerical rating scales. After capsaicin exposure, the participants rinsed their mouth for 10 s with a different solution in each session (3.5% casein, 3.5% whey, 3.5% lactose (non-protein control) and skimmed milk (active/positive control)). Mechanical (64, 128 and 256 mN pinprick) and thermal (5, 40, 45 and 50 ̊C) sensitivity of the tongue was measured using semi-quantative sensory testing at baseline, immediately after capsaicin exposure and when the scores for unpleasantness and burning intensity reached the minimum value of 0. Thermographic images of the tongue were taken at the same time-points. Overall, no statistically significant difference in unpleasantness and burning intensity was found between the four sessions (P ≥ 0.070). Explorative pair-wise comparisons, however, showed slight short-term reduction in unpleasantness and burning intensity when comparing the casein solution with the lactose solution (P ≤ 0.020). Scores for burning intensity and unpleasantness varied over time (P ≤ 0.001). Statistically significant changes in heat and mechanical sensitivity was observed between time-points (P < 0.001) but not sessions (P ≥ 0.410). An increased sensitivity towards heat and a decreased sensitivity towards mechanical stimuli was observed after capsaicin exposure compared with baseline (P < 0.001). Similarly, changes in thermographic temperature of the tongue was observed between time-points (P < 0.001), but not sessions (P ≥ 0.827). An increased maximum, minimum and average temperature of the tongue was observed immediately after capsaicin exposure compared with baseline (P < 0.001). In conclusion, short-term rinsing with room temperature milk proteins did not robustly alter capsaicin-induced oral burning sensation, unpleasantness, somatosensory changes or tongue temperature compared with control. Further studies exploring the effects of increased rinsing time and concentrations are needed in the future.