Lactose Content Research Articles

The Housing System Contributes to Udder Health and Milk Composition

The aim of this study was to determine the effect of the housing system and somatic cell count (SCC) on the composition and fatty acid profile of milk. A total of 419 milk samples were collected from one herd of 210 cows; 90 cows were kept in the tie-stall system, and 120 cows were kept in the free-stall system. The cows received the same fodder. Samples were collected four times, in winter. Udder health was evaluated based on SCC. The tie-stall system, mainly due to individual care, was superior to the free-stall system. Milk from cows kept in the tie-stall system had lower (p < 0.01) SCC by 72 ths mL−1 cells than milk from cows kept in the free-stall system. An increase in SCC was accompanied by decreases in daily milk yield and lactose concentration. Milk from cows housed in the tie-stall barn had higher polyunsaturated fatty acid (PUFA) contents and a lower n-6/n-3 PUFA ratio. Milk with a higher SCC contained more PUFAs and fewer monounsaturated fatty acids (MUFAs). Tie-stall housing contributed to an increase in the proportions of acids beneficial to the health of consumers. A comparison of two housing systems for cows on one farm showed that the free-stall system was associated with a higher SCC and a less favorable milk composition and fatty acid profile.

Impedance Spectroscopy: A New Tool for Dairy Analysis

In this work, an impedimetric bioelectronic tongue (bioET) formed by an array of interdigitated microelectrodes sensors was developed and applied in the discrimination of chemical components usually found in milk samples. Few studies of impedimetric bioETs applied in the dairy industry can be found in the bibliography due to the complexity of the characterization of milk matrixes. Therefore, the development and study of the capabilities of multisensory systems containing different advanced materials such as nanomaterials combined with biological molecules is a new field of research.In order to develop an array of sensors with enhanced sensitivity and selectivity, sensors were modified with silver nanoparticles (AgNPs) and enzymes including galactose oxidase (GaOx), glucose oxidase (GOx), beta-galactosidase (β-gal), urease (Ure) and lipase (Lip) were immobilized on the sensors surface. Silver nanoparticles have proved to be an excellent option to enhance the performance of biosensors due to their electrochemical properties, their high electrical conductivity, and their ability to amplify bio electrochemical signals.Atomic force microscopy (AFM) was used to study the distribution of AgNPs and enzymes in the sensor surface. Silver nanoparticles showed a homogeneous arrangement along the entire surface, moreover after the enzyme immobilisation a pronounced increase in the sensors surface roughness was observed ensuring the process of the biological molecule (Figure 1.A and Figure 1.B).The impedance analysis of standard solutions of interest in milk (glucose, galactose, lactose, urea and triglycerides) demonstrated that sensors with a higher concentration of silver nanoparticles (AgNPs) in their structure reported higher sensitivities towards compounds found in milk with a reduction in the impedance module, indicating that there has been an improvement in electronic transfer due to the interaction of the nanomaterial and the electrode surface an example of the sensor behaviour is shown in Figure 1.C. Moreover, sensors that combined the nanomaterial with an enzyme showed a greater ability to differentiate between increasing concentrations of the enzymes target molecules (Figure 1.D). Taking as an example the case of glucose the sensor modified with AgNPs and glucose oxidase achieved a lower impedance module compared with the other sensors thanks to its lower resistance to electronic transfer in the sensor due to the enzymatic activity enhanced by the silver nanoparticles.Once all the standard solutions had been analysed, the chemometric analysis of their response was carried out applying a principal components analysis (PCA) approach which showed that the bioET developed was able to discriminate between the standard solutions (glucose, galactose, lactose, urea and triglycerides), resulting in five clusters according to their nature with a 79% of the variance of the original data obtained by the first two components of the system. Sugars appear in the positive region of the first component divided into three groups (lactose, galactose and glucose). In the negative region of the first component appears urea and the suspension of triglycerides that can be differentiated over the second component.Lastly, a first approach was made to the analysis of milk samples with different nutritional characteristics such as their fat, lactose and urea content. The utilization of the bioelectronic tongue showed how the different contents of molecules of interest was directly related with the response of the impedimetric sensors due to changes in the interaction of the sensors surface and the milk matrix. As it was expected, higher concentrations of fat caused an increase in the impedance module due to their interference in the electronic transfer process. Furthermore, it was confirmed that the biosensors developed showed specific responses towards milk samples with higher values of sugar and proteins contents ensuring a high degree of cross-selectivity in the system.Figure 1: A) Characterization by AFM of the sensor modified with AgNPs. B) Characterization by AFM of the biosensor with AgNPs and GOx. C) Nyquist diagram of sensors with 20 (orange), 30 (black) and 40 μl (blue) of AgNPs in 0.1M glucose. D) Nyquist diagram of the response of a sensor with AgNPs and GOx in glucose 0.1M (red), 0.01M (green) and 0.001M (grey). Figure 1

Effects of Nutrients on the Growth of and Free Exopolysaccharide Biosynthesis by Streptococcus thermophilus 937 in a Chemically Defined Medium.

The free exopolysaccharide (f-EPS) produced by Streptococcus thermophilus is a natural texture modifier with health-promoting properties and has thus become one of the most interesting metabolites for researchers. The present work aimed to further understand the nutritional requirements for the growth of and the f-EPS production by S. thermophilus. The types and concentrations of compounds in the complete chemically defined medium were changed in turn to evaluate the effects of single nutrients on the growth of and f-EPS production by S. thermophilus 937. The results showed that cysteine, glutamine, histidine, methionine, tryptophan, tyrosine, leucine, isoleucine, and valine played an important role in maintaining the rapid and stable growth of S. thermophilus 937. S. thermophilus 937 also required calcium pantothenate, niacin, pyridoxine, riboflavin, and thiamine hydrochloride as essential nutrients for growth. Increases in the concentrations of lactose, glutamate, histidine, or isoleucine significantly increased the production of free exopolysaccharide by S. thermophilus 937, and when the lactose concentration increased to 20 g·L-1 and the concentration of the three-amino-acid combination increased to 15 mM, the f-EPS yield increased to a maximum of 35.34 μg·mL-1. This finding indicated that lactose and the 3 amino acids exert synergistic effects on the promotion of f-EPS production. In addition, lactose and the three amino acids have strain specific promoting effects on f-EPS production by S. thermophilus. This study provides a further understanding of the effects of nutrients on the biosynthesis of f-EPS by S. thermophilus.

Lactational performance, rumen fermentation, nutrient use efficiency, enteric methane emissions, and manure greenhouse gas-emitting potential in dairy cows fed a blend of essential oils

The objective of this experiment was to investigate the effects of an essential oil (EO) blend on lactational performance, rumen fermentation, nutrient utilization, blood variables, enteric methane emissions and manure greenhouse gas-emitting potential in dairy cows. A randomized complete block design experiment was conducted with 26 primiparous and 22 multiparous Holstein cows. A 2-wk covariate and a 2-wk adaptation periods preceded a 10-wk experimental period used for data and sample collection. Treatments were: (1) basal diet supplemented with placebo (CON); and (2) basal diet supplemented with a blend of EO containing eugenol and geranyl acetate as main compounds. Supplementation with EO did not affect dry matter intake, milk and energy-corrected milk yields, and feed efficiency of cows, compared with CON. Milk fat and lactose concentrations were increased, and milk total solids (TS) concentration and milk fat yield tended to be increased by EO. Multiparous cows supplemented with EO tended to have slightly decreased dry matter and crude protein digestibility compared with CON multiparous cows. There was a tendency for increased ruminal pH by EO, whereas other rumen fermentation variables did not differ between treatments. Daily methane emission was not affected by EO supplementation, but methane emission intensity per kg of milk fat was decreased by 8.5% by EO. Methane emission intensity per kg of milk lactose and milk TS were decreased and methane emission intensity per kg of milk yield tended to be decreased by up to 10% in EO multiparous cows, but not in primiparous cows. The greenhouse gas-emitting potential of manure was not affected by EO supplementation. Compared with CON, fecal nitrogen excretion was increased by EO supplementation in multiparous, but not in primiparous cows, and milk nitrogen secretion (as a % of nitrogen intake) tended to be increased in EO supplemented cows. Blood variables were not affected by EO supplementation in the current study. Overall, dietary supplementation of EO did not affect lactational performance of the cows, although milk fat and lactose concentrations were increased. Most enteric methane emission metrics were not affected, but EO decreased methane intensity per kg of milk fat by 8.5%, compared with the control.

Phenotypic and genetic characterisation of methane emission predicted from milk fatty acid profile of Sarda dairy ewes

Individual methane emissions are a potential breeding goal for selection plans aimed at improving the sustainability of ruminant farming systems. However, a large-scale recording of individual methane emissions is hampered by the high costs of the equipment and the logistics of the experiments. Equations have been developed to predict methane emissions in dairy cattle based on variables such as dry matter intake (DMI), gross energy intake, body weight and milk fatty acids (FAs) profile. No equations are currently available for dairy sheep. The aims of this study were: (i) to estimate the enteric methane yield (eMY, expressed as g/kg of DMI) and enteric methane intensity (eMI, expressed as g/kg of FPCM) of dairy sheep using equations developed for dairy cattle that consider as predictors milk FA; (ii) to evaluate the effect of stage of lactation, parity and month of lambing on eMY and eMI; (iii) to estimate the heritability of eMY and eMI. For this purpose, 964 individual milk samples from Sarda dairy ewes were analysed for milk composition and FA profile. Nine different equations were used to predict eMY and eMI. Values of eMY ranged from 19.4 g/kg to 20.4 g/kg of DMI, whereas values of eMI ranged from 15.1 g/kg to 21.0 g/kg of DMI, respectively. Stage of lactation was an important factor in the variability of eMY (p < .01). Indeed, this trait increased towards the end of lactation. Both eMY and eMI were negatively correlated with milk yield, lactose concentration and urea and positively correlated with fat concentration and NaCl, respectively. Heritability of eMI and eMY estimated using a single trait model was 0.13 ± 0.05 and 0.05 ± 0.04, respectively. The values of heritability estimated for eMY using a bivariate models ranged from 0.10 to 0.16 and they were higher than the value estimated for eMI. Results of the present study, even if based on prediction equations developed for cows, increased the knowledge about the phenotypic and genetic background of methane emissions in Sarda dairy sheep.

Postprandial metabolism and gut permeability in calves fed milk replacer with different macronutrient profiles or a whole milk powder

Significant differences exist in the composition of current milk replacers (MR) and bovine whole milk. This study investigated how the macronutrient profile of 3 different MR formulations containing varying amounts of fat, lactose, and protein, and a whole milk powder (WP), affect postprandial metabolism and gut permeability in male Holstein calves. Sixty-four calves (45.4 ± 4.19 kg [mean ± SD] and 1.8 ± 0.62 d of age) were blocked in order of arrival to the facility and within each block, calves were randomly assigned to 1 of 4 treatments. Treatments included a high-fat MR (HF: 25.0% dry matter [DM] fat, 22.5% protein, 38.6% lactose; n = 14), a high-lactose MR (HL: 44.6% lactose, 22.5% protein, 18.0% fat; n = 17), a high-protein MR (HP: 26.0% protein, 18.0% fat, 41.5% lactose; n = 17), and WP (26.0% fat, 24.5% protein, 38.0% lactose; n = 16). Calves were fed 3.0 L (135 g/L) 3 times daily at 0600, 1200, and 1800 h with a teat bucket. Milk intake was recorded daily for the first 28 d after arrival, and blood sampling and body weight measurements were performed at arrival and on d 7, 14, 21, and 27. Gut permeability was estimated from fractional urinary excretion of indigestible markers (Cr-EDTA, lactulose, and d-mannitol) administered as a single dose on d 21 instead of the morning milk meal. Digestibility was determined simultaneously from a total collection of feces over 24 h. Postprandial dynamics were measured on d 28 by sequential blood sampling over 7.5 h. Dry matter intake of MR over 28 d was slightly greater in calves fed HL and HP than in WP. Recovery of Cr-EDTA and d-mannitol over a 24-h urine collection was greater in calves fed WP and HP than HL calves. Apparent total-tract digestibility of crude ash, protein, and fat did not differ among treatments; however, DM digestibility was lower in calves fed WP than in other treatment groups. In addition, abomasal emptying, as indicated by the area under the curve (AUC) for acetaminophen, was slower in calves fed WP than in calves fed HF and HL. The AUC for postprandial plasma glucose was lower in calves fed HL than WP and HF and lower in calves fed HP than WP. The AUC for postprandial serum insulin was greater in calves fed HP than WP and HF, whereas calves fed HL did not differ from the other treatments. Postprandial triglycerides were greater in calves fed WP, and postprandial adiponectin was higher in calves fed HL than other treatments. The high content of lactose and protein in MR had a major effect on postprandial metabolism. This raises the possibility of optimizing MR formulations to maintain metabolic homeostasis and influence development.

Effects of copper, zinc, and manganese source and inclusion during late gestation on beef cow-calf performance, mineral transfer, and metabolism.

To determine effects of Cu, Zn, and Mn source and inclusion during late gestation, multiparous beef cows [n = 48; 649 ± 80 kg body weight (BW); 5.3 ± 0.5 body condition score (BCS)] were individually-fed hay and supplement to meet or exceed all nutrient recommendations except Cu, Zn, and Mn. From 91.2 ± 6.2 d pre-calving to 11.0 ± 3.2 d post-calving, cows received: no additional Cu, Zn, or Mn (control, CON), sulfate-based Cu, Zn, and Mn (inorganic, ITM) or metal methionine hydroxy analogue chelates (MMHAC) of Cu, Zn, and Mn at 133% recommendations, or a combination of inorganic and chelated Cu, Zn, and Mn (reduce and replace, RR) to meet 100% of recommendations. Data were analyzed with treatment and breeding group (and calf sex if P < 0.25 for offspring measures) as fixed effects, animal as experimental unit, and sampling time as a repeated effect for serum, plasma, and milk measures over time. Post-calving cow liver Cu was greater (P ≤ 0.07) in MMHAC compared with all other treatments. Calves born to RR had greater (P ≤ 0.05) liver Cu than ITM and CON, and MMHAC had greater (P = 0.06) liver Cu than CON. Liver Mn was less (P ≤ 0.08) for RR calves than all other treatments. Calf plasma Zn was maintained (P ≥ 0.15) from 0 to 48 h of age in ITM and MMHAC but decreased (P ≤ 0.03) in CON and RR. Gestational cow BW, BCS, and metabolites were not affected (P ≥ 0.13) by treatment, but gestational serum thiobarbituric acid reactive substances (TBARS) were greater (P = 0.01) for CON than MMHAC. Treatment did not affect (P ≥ 0.13) calf birth size, vigor, placental size and minerals, or transfer of passive immunity. Neonatal calf serum Ca was greater (P ≤ 0.05) for MMHAC than all other treatments; other calf serum chemistry and plasma cortisol were not affected (P ≥ 0.12). Pre-suckling colostrum yield, and lactose concentration and content, were greater (P ≤ 0.06) for MMHAC compared with ITM and RR. Colostral triglyceride and protein concentrations were greater (P ≤ 0.08) for RR than MMHAC and CON. Cow lactational BW and BCS, milk yield and composition, and pre-weaning calf BW and metabolism were not affected (P ≥ 0.13) by treatment. Lactational serum TBARS were greater (P = 0.04) for RR than CON at day 35 and greater (P ≤ 0.09) for MMHAC at day 60 than all other treatments. Source and inclusion of Cu, Zn, and Mn altered maternal and neonatal calf mineral status, but calf size and vigor at birth, passive transfer, and pre-weaning growth were not affected in this study.

The Effect of Using Crude Papain as Coagulant on Chemical Characteristics and Energy Value of Susu Goreng Made from Cow’s Milk

This study aimed to determine the effect of crude papain on the chemical characteristics and energy value of fried milk made from cow’s milk. A completely randomized design (CRD) was used in this experiment with 4 treatments and 4 replicates. The levels of crude papain tested were P1 = 0.5%, P2 = 1%, P3 = 1.5% and P4 = 2.0%, of milk volume. The variables studied included protein content, total sugar, lactose, calcium and energy value. The collected data were processed according to the variance analysis procedure. The fried milk produced had protein content; 9.9 – 11.87%, fat 6.59 – 9.59%, lactose 4.84 – 8.72%; total sugar 28.25 – 36.75%; calcium 0.23 – 0.26% and energy value 2712.47 – 3388.25 calories/100g. The results of variance analysis showed that the treatment had a very significant effect (P&lt;0.01) on fat content, total sugar, and a significant effect (P&lt;0.05) on lactose content, but not significant (P&gt;0.05) on protein, calcium, and energy value of fried milk. It was concluded that the use of crude papain produced fried milk with varying levels of fat, total sugar and lactose but protein, calcium and energy value tended to be the same. The best results were obtained with the use of crude papain 0.5%.

The Effect of Crude Papain as Coagulant on Chemical Characteristics and Energy Value of Susu Goreng Based On Goat’s Milk

Experiment aimed was determined the influence of using crude papain as coagulant on the chemical properties and energy value of susu goreng based on goat milk. The completely randomized design (CRD) with 4 treatments and 4 replications was applied in this experiment. The crude papain levels tested consist of P1= 0.5%, P2= 1.0%, P3= 1.5% and P4= 2.0% of milk volume. The variables measured was moisture, protein, fat, total sugar, lactose, calcium and energy value. Susu goreng obtained has moisture ranged of 52.99 to 54.08%; protein 24.88 to 29.05%; fat 22.30 to 25.75%; lactose 0.69 to 1.38%; total sugar 2.72 to 4.4%; calcium 0.68 to 0.77% and energy value 1989.28 to 2507.09 kcal/100 g. Analysis of variance showed that treatment had close significant effect (P&lt;0.01) on total sugar, calcium and lactose, significant (P&lt;0.05) on energy value but had no significant (P&gt;0.05) on moisture, protein and fat. It can be concluded that the use of crude papain as a coagulant with a level of 0.5 to 2% produces susu goreng with varying chemical characteristics. The use of crude papain level 0.5% is the best where the susu goreng produced has the characteristics of the higher protein content, calsium and energy value, the lowest lactose content and total sugar.

Influence of multiple parameters on the crystallinity of dairy powders

Caking in powdered foods causes practical difficulties in solubilising the powder and interrupts the free flow from the container during manufacture and final use. This research investigated the caking tendency of cheese and milk powders stored at different relative humidity environment by low field, time domain 1H NMR, Magic Sandwich Echo sequence. The caking tendency of cheese powders was higher than milk powders. On the other hand, surface fat content of whole fat milk powder had an abrupt change due to lactose crystallisation at 60% relative humidity, which corresponded to a critical moisture content of 10%. As an overall conclusion, the lactose content was more dominant than fat content to trigger caking. However, it was inferred that the effect of the salt amount, which differed due to the nature of the samples, was more significant for caking development in milk and cheese powders.

Bioavailability of a novel rumen protected methionine supplement and its effect on milk production and body composition in dairy cows

Our objective was to evaluate the bioavailability of a rumen-protected Met product (EMT 3.4) using milk selenium (Se) marker method and its impact on milk production and body composition in dairy cows. Twelve multiparous Holstein cows (82 ± 27 days in milk, 38.7 ± 3.4 kg/d of milk; mean ± SD) were used in a replicated 3 × 3 Latin-square design with 21 d periods. Prior to the study, cows were fed Se-yeast for 2 wk to reach stable milk Se concentration. Treatments were 1; a negative control diet (NCT) providing 100% of the metabolizable protein (MP) requirement and 90% of the metabolizable Lys and Met requirements, 2; a positive control diet (PCT) providing 101% of the MP, and 110% of the Met and Lys requirements (Met supplied by Smartamine M, Adisseo), and 3; an experimental Met treatment (EMT; Met supplied by EMT 3.4, Ajinomoto Inc.) that was formulated to provide 101% of the MP, and 110% of the metabolizable Met and Lys requirements (AMTS.Cattle.Professional utilizing CNCPS 6.5.5 models). The NCT cows were not supplemented with additional Met or Lys, whereas supplemental Lys for both the EMT and PCT diets was supplied by Aji-Pro L (Ajinomoto). The PCT and EMT treatments decreased milk Se-to-N ratio (i.e. bioavailability; Se:N), by 11% and 9.5% respectively compared with NCT (P < 0.05). The PCT increased DMI and tended to increase milk yield compared to NCT and EMT. The PCT treatment increased yields of milk protein, solids, lactose, and milk lactose concentration compared to NCT and EMT treatments. The EMT treatment increased milk urea nitrogen (MUN) concentration compared with NCT and PCT. However, the potential for milk Se to be inconsistently diluted due to differences in MUN and DMI poses challenges with interpretation. The lack of measurable production responses when supplementing EMT compared to NCT, may indicate less bioavailable Met than the bioavailability calculation assumes.

Physico-Chemical and Bacteriological Qualities of Raw Milk from Collection Centers and Hawking Activity in the Rabat-Salé-Kenitra Region (Morocco)

The study aims to analyze the two circuits of the dairy chain: authorized and unauthorized, by studying the parameters influencing the physico-chemical and bacteriological quality of milk in both networks. Samples of raw milk (n=22), collected from nine collection centers (CCL): four authorized and five unauthorized in the region of Kenitra, and four hawking points in the region of Rabat, during a period between March and May 2022, were analyzed to evaluate their physicochemical and bacteriological qualities. The physicochemical quality of the milk included the measurement of chlorides, lactose and fat content, and the determination of titratable acidity and freezing point. The bacteriological quality was assessed by counting the total aerobic mesophilic flora (TAMF), total and fecal coliforms, presumed pathogenic staphylococci and searching for Salmonella. The fat content varies considerably depending on where the milk samples are collected; the average is 4.13% for licensed collection centers, versus 2.94% for unlicensed collection centers and 2.82% for hawking activity. In terms of hygienic quality, the average bacterial load of TAMF in milk from the authorized collection centers is 3.8×108 CFU/ml. Total coliforms (TC) are present with an average rate of 9.37 ×105 CFU/ml with an average portion of 7.87 ×103 CFU/ml in fecal coliforms (FC), and 1.03 ×106 CFU/ml for presumed pathogenic staphylococci. On the other hand, milk samples from unauthorized collection centers and hawking activity showed higher levels of microbial contamination than those from licensed collection centers. Salmonella was not detected in any of the samples analyzed. The non-compliance with hygiene practices and the late application of cold during the milking, the collection, and the transportation of raw milk, partly explain the origin of this finding.

Evaluation of the Metabolic Relationship between Cows and Calves by Monitoring Calf Health and Cow Automatic Milking System and Metabolic Parameters.

With this study, we investigated the relationship between a cow's and calf's metabolic state, and its effect on health status. To achieve this, 20 calves of primiparous and 20 calves of multiparous cows were selected. The calves were monitored for 30 days and scored for signs of disease, as described in McQuirk (2008); according to score, they were divided into healthier calves; the Low calf score group (LCS, 5-8), Medium calf score group (MCS, 9-12) and High calf score group (HCS, 14-17); or calves most prone to disease. Their mothers were monitored for the same period with a Lely Astronaut 3 herd management system (Lely, Maassluis, The Netherlands) for rumination time, milk yield, milk fat, protein, lactose concentrations and milk fat to protein ratio. Both cows and calves were sampled for blood, and concentrations of glucose with β-hydroxybutyrate were registered. The results indicate that primiparous cows had a 16% higher blood glucose concentration (3.03 mmol/L SE = 0.093) compared with multiparous cows (2.61 mmol/L, SE = 0.102) (p < 0.01), but no difference in calf glucose was recorded. Β-hydroxybutyrate levels did not differ significantly between cows and calves by parity group. Rumination time was longest in the HCS group at 550.79 min/d. and was 16% longer compared with the LCS group (461.94 min/d.; p < 0.001) and 8% longer compared with the MCS group (505.56 min/d.; p < 0.001). The MCS group rumination time mean was statistically significantly higher compared with the LCS group by 8% (p < 0.001). Milk yield was also highest in the HCS group (44.8 kg/d.): 19% higher compared with the MCS group (36.31 kg/d., p < 0.001) and 13% higher than the LCS group (38.83 kg/d., p < 0.001). There was also a significant difference between the MCS and LCS groups of 6% (p < 0.001). The HCS group had the highest milk fat concentration (4.47%): it was 4% higher compared with the LCS group (4.28%, p < 0.001) and 5% higher than the MCS group (4.25%, p < 0.001). Milk fat to protein ratio was highest in the HCS group (1.21) and was 7% higher than in the MCS group (1.12, p < 0.001) and 8% higher than in the LCS group (1.11, p < 0.001). The LCS group was determined to have the highest concentration of milk lactose (4.66%). It was 1% higher compared with the MCS group (4.62%, p < 0.001) and 1.07% higher than the HCS group (4.61%, p < 0.001). We can conclude that parity did not affect calf health status and that cows of the HCS group showed symptoms of negative energy balance expressed through higher milk yield, higher milk fat concentration and higher milk fat to protein ratio, with lower milk lactose concentration. Further and more thorough research is needed to evaluate the relationship between pregnant cows and calves.

Fermentation and Quality Characteristics of Yogurt Treated with Bifidobacterium longum.

The fermentation and quality characteristics of yogurt were investigated according to the inoculation concentration of Bifidobacterium longum. The total sugar content of yogurt decreased as the fermentation time increased, and with an increased concentration of B. longum treatment the fermentation time decreased rapidly. As fermentation progressed, the lactose content decreased rapidly at the beginning and gradually decreased as the pH decreased. Depending on the B. longum treatment concentration, the lactose content varied from 0.29 ± 0.01 to 0.47 ± 0.01% and was 0.5% or less in all experimental groups. The experimental group inoculated with 0.0015% of B. longum displayed the best results in all categories, including pH, total acidity, lactic acid content, solid non-fat content, and total lactic acid bacteria count, which are factors that determine the quality of yogurt. In summary, the experimental group inoculated with 0.0015% of B. longum was determined to be the highest quality yogurt.

RAW COW MILK QUALITY: PHYSICOCHEMICAL, MICROBIOLOGICAL, AND SEASONAL VARIATION

Milk serves as a vital source of essential nutrients in human diets and must be safe for consumption. In the dairy industry, it is crucial to analyze the physicochemical and microbiological properties of raw cow milk (RCM) throughout the year to gather fundamental information, as milk quality significantly influences the final quality of dairy products. This study aimed to investigate the physicochemical and microbiological properties of 60 RCM samples collected from 15 primary milk collection centers in Qazvin, Iran, and assess the impact of seasonal variation on these properties. The study discovered that the RCM samples contained &gt;7 Log10 cfu/mL of Staphylococcus aureus, total coliform count, aerobic mesophilic plate count, and mold and yeast in 15%, 30%, 37%, and 28% of the samples, respectively. The results indicated that aerobic mesophilic plate count, mold and yeast, total coliform count, and Staphylococcus aureus were higher in warmer seasons compared to colder seasons. Furthermore, the study revealed that the average pH, freezing point, solid-not-fat, and protein content were higher in warm seasons, while the average acidity, lactose, and fat content were higher in cold seasons. The physicochemical and microbiological properties of RCM in the Qazvin region were found to be below the acceptable quality value. Although seasonal variation throughout the year affected the microbial and physicochemical quality of RCM, the differences were not statistically significant (p&gt;0.05), except for the solid-not-fat value in winter (p&lt;0.05).

Characteristics of lactose-free/low-lactose fermented dairy products containing microorganisms that are part of the kefir grain consortium: Scoping review

Introduction: There are a significant number of scientific publications dedicated to the analysis of lactose-free and low-lactose fermented milk products, primarily in the context of studying specific microorganisms or starter cultures and their functioning under conditions of limited lactose content. Nevertheless, the synthesis of accumulated data has not been sufficiently highlighted, considering that a large part of the research was conducted over the past 10 years, and an intensive examination of this issue has only begun in the recent past.Purpose: To systematically and critically analyze scientific research that sheds light on the specifics of fermented milk products with a reduced lactose level, focusing on a comparative study of standard fermented milk products and their low-lactose or lactose-free modifications. Special attention is paid to fermented milk products containing microorganisms that are part of the kefir fungus consortium.Materials and Methods: Sources for the review were selected from the Scopus, ScienceDirect, RISC (Russian Index of Science Citation), and Google Scholar databases. Out of 208 publications relevant in terms of keywords, 34 were selected for analysis. The main criterion for selecting articles was a description in them of studies on the use of low-lactose or lactose-free milk as a medium for cultivating starter cultures. This review of the subject area is based on the PRISMA-ScR protocol.Results: Many scientific studies indicate that the prepared low-lactose or lactose-free fermented milk products exhibited similar or improved physicochemical and organoleptic characteristics compared to standard fermented milk products. In experiments aimed at evaluating microbiological characteristics, it was observed that the concentration of lactic acid bacteria in the analyzed products either matched, was lower, or was higher than in traditional fermented milk products. In some publications, scientists found that the final fermented milk product had deteriorated organoleptic and physicochemical parameters. However, all reviewed low-lactose or lactose-free fermented milk products met the standards and regulatory requirements of the countries in which the respective research was conducted.Conclusion: The development of low-lactose and lactose-free fermented milk products is a relevant direction in the food industry, considering their similarity to conventional products and adaptability for consumption by individuals with varying degrees of lactose intolerance. There are nuances related to the duration of the fermentation process, organoleptic characteristics, acidity level, syneresis, preservation, and growth dynamics of microorganisms. These features can be dictated by specific strains of microflora used in the starter and, most often, their influence remains minimal. The results obtained in this study may be useful for selecting starter cultures when designing various fermented milk products, including yogurt, fortified yogurt, kefir, ayran, ryazhenka, and acidophilus. For a deeper understanding of the interaction of the modified glucose-galactose medium with various strains and species of lactic acid bacteria, further experimental work is needed, considering that the activity of these bacteria directly determines the quality characteristics of the final fermented milk product.

Nutritional, physical and sensorial properties of food-grade emulsion powder enriched with soy milk and whey protein permeates

Protein deficiency is a common chronic malnutrition in Bangladesh, and it is linked to low socio-economic status. The study was to develop a high calorie powder based on soy milk (SM) and whey protein permeates (WPP). Soy milk was extracted soaking it at 55ºC and 60ºC for 1 h and blanching it at 80ºC for 10 min. The chemical composition of extracted SM and WPP along with developed high calorie emulsion (HCE) powder was analyzed. The result suggested that soaking at 60ºC for 1 h and blanching at 80ºC for 10 min had higher solid content. The moisture, ash, protein, fat, lactose and carbohydrate content in SM at 60ºC were 90.02 %, 1.20 %, 5.38 %, 2.15 %, 0.0 % and 1.25 % respectively, whereas WPP contained 8.18 %, 7.85 %, 16.1 %, 0.0 %, 42.92 % and 24.95 %, respectively. Four emulsions were formulated to develop HCE powder to supply 1 Kcal /ml. Nutritional analysis suggested that formula C (70 % SM and 30 % WPP) shows the highest amino acid and mineral contents except zinc. The sensory analysis showed that formula D (50 % SM and 50 % WPP) and formula C were equally acceptable. Only formula A (100 % SM) was less accepted by the panelists because of the deep brown color and off flavor of soy milk liquid. However, high calorie powder can be prepared by using SM and WPP to supply a sufficient amount of nutrition.

Ulasan Ilmiah: Karakteristik Mutu Nutrisi, Organoleptik dan Mikrobiologis Kefir Susu Kambing

Kefir is a beverage product obtained through the fermentation process of pasteurized milk using a starter from kefir grain. Kefir can be made using goat's milk. Processing of goat milk into kefir is a method used to increase the fat, protein and carbohydrate content of goat milk. There are many factors that affect the quality of kefir. This study aims to determine the potential of of goat's milk kefir based on nutritional, organoleptic and microbiological parameters. The method used is a literature study that comes from various data sources. The selection of cited journals has gone through a screening process based on inclusion, special and exclusion criteria. The results showed, making goat milk kefir requires 12-36 hour of fermentation proces and using a concentration of kefir grains ranging from 2.5 – 5%. This proces, produces a kefir product with good organoleptic characteristics with a white color, distinctive aroma of kefir, sour taste, and soft texture. Goat milk kefir generally has a protein content of 2.96 – 3.66%, fat 2.02 – 5.35%, carbohydrates 2.45 – 5.6%, ash 0.42 – 0.80, ethanol 0.72% with an acidic pH. Goat's milk kefir has a lower lactose concentration of 0.2-0.5% than cow's milk. It also contains various types of microorganisms, including LAB and yeast, which are present in kefir grains which vary widely, with an amount of around 6.4 x 104 to 8.5 x 108 and 1.5 x 105 to 3.7 x 108 cfu/ml. The number of microbes in the kefir has met the standard as a functional food.

Altering palmitic acid and stearic acid ratios in the diet of early-lactation Holsteins under heat stress: Feed intake, digestibility, feeding behavior, milk yield and composition, and plasma metabolites

The objective of this study was to evaluate the effects of varying the ratio of dietary palmitic (C16:0; PA) and stearic (C18:0; SA) acids on nutrient digestibility, production, and blood metabolites of early-lactation Holsteins under mild-to-moderate heat stress. Eight multiparous Holsteins (body weight = 589 ± 45 kg; days in milk = 51 ± 8 d; milk production = 38.5 ± 2.4 kg/d; mean ± standard deviation) were used in a duplicated 4 × 4 Latin square design (21-d periods inclusive of 7-d data collection). The PA (88.9%)- and SA (88.5%)-enriched fat supplements, either individually or in combination, were added to diets at 2% of dry matter (DM) to formulate the following treatments: (1) 100PA:0SA (100% PA + 0% SA), (2) 66PA:34SA (66% PA + 34% SA), (3) 34PA:66SA (34% PA + 66% SA), and (4) 0PA:100SA (0% PA + 100% SA). Diets offered, in the form of total mixed rations, were formulated to be isonitrogenous (crude protein = 17.2% of DM) and isocaloric (net energy for lactation = 1.69 Mcal/kg DM), with a forage-to-concentrate ratio of 40:60. Ambient temperature-humidity index averaged 72.9 throughout the experiment, suggesting that cows were under mild-to-moderate heat stress. No differences in DM intake across treatments were detected (mean 23.5 ± 0.64 kg/d). Increasing the dietary proportion of SA resulted in a linear decrease in total-tract digestibility of total fatty acids, but organic matter, DM, neutral detergent fiber, and crude protein digestibilities were not different across treatments. Decreasing dietary PA-to-SA had no effect on the time spent eating (340 min/d), rumination (460 min/d), and chewing (808 min/d). As dietary PA-to-SA decreased, milk fat concentration and yield decreased linearly, resulting in a linear decrease of 3.5% fat-corrected milk production and milk fat-to-protein ratio. Feed efficiency expressed as kg 3.5% fat-corrected milk/kg DM intake decreased linearly with decreasing the proportion of PA-to-SA in the diet. Treatments had no effect on milk protein and lactose content. A linear increase in de novo and preformed fatty acids was identified as the ratio of PA to SA decreased, while PA and SA concentrations of milk fat decreased and increased linearly, respectively. A linear reduction in blood nonesterified fatty acids and glucose was detected as the ratio of PA to SA decreased. Insulin concentration increased linearly from 10.3 in 100PA:0SA to 13.1 µIU/mL in 0PA:100SA, whereas blood β-hydroxybutyric acid was not different across treatments. In conclusion, the heat-stressed Holsteins in early-lactation phase fed diets richer in PA versus SA produced greater fat-corrected milk and were more efficient in converting feed to fat-corrected milk.

Physicochemical, microbiological, and sensory properties of low-lactose yogurt using Streptococcus thermophilus with high β-galactosidase activity.

Lactose maldigestion or intolerance affects a large number of individuals worldwide. If lactose is hydrolyzed by the β-galactosidase enzyme during the fermentation process, lactose-intolerant individuals can consume milk products without experiencing diarrhea, flatulence, or other symptoms. We isolated and characterized Streptococcus thermophilus, which exhibits high β-galactosidase activity. This was then used as a starter culture with Lactobacillus delbrueckii subsp. bulgaricus in yogurt to determine the effects of different starter ratios and fermentation temperatures on its organoleptic and physical properties. The β-galactosidase activity of the isolated strain was 2.60 units mg-1 . The optimal temperature was 42 °C for St. thermophilus to acidify yogurt faster than at other temperatures and it was effective in hydrolyzing the lactose in the media and yogurt. The lactic acid bacteria (LAB) population in 37 °C fermented yogurt was higher than in the other samples, but the starters St. thermophilus and Lb. bulgaricus with a ratio of 2:1 used lactose more effectively than other sample ratios. The lactose content decreased significantly at 37 °C, where it was ~50% hydrolyzed. The acceptability of the sensory properties of yogurt was unaffected by relative lower fermentation temperatures (30 and 37 °C), despite using different ratios of St. thermophilus and Lb. bulgaricus as starter cultures. © 2023 Society of Chemical Industry.