Functional Properties Of Milk Research Articles

Biochemical and functional characterization of milk from alpina and toggenburg goat breeds

Objective: This work aimed to evaluate the biochemical and functional properties of milk from two goat breeds (Alpina and Toggenburg) which could give goat's milk a higher added value and market, making it an attractive option for milk producers.
 Design/methodology/approach: Several biochemical analyses were performed to both breed milks: Total Fat (Gerber); Total Protein (Lowry); Lactose (reducing sugars); Fatty acid composition (Mass-mass coupled gas chromatography) and antihypertensive activity (angiotensin-converting enzyme inhibition). To determine possible applications, functional characteristics of yogurt and cheese were also evaluated. Statistical analyses were performed using NCSS software.
 Results: Fat content of Alpina breed was higher than Toggenburg’s (4.76% vs. 2.96%, α=0.00013), as was lactose (8.26% vs. 5.37%, α=0.003), while Toggenburg presented higher protein content (5.53% vs. 4.77%, α=0.00016). Potential biologically active fatty acids were found in both milks in similar concentrations. Toggenburg milk sowed higher antihypertensive activity than Alpina (100% vs 77.27%), which was maintained and in some cases increased, when fermented to obtain different derivatives such as cheese and yogurt.
 Limitations on study/implications: Further study is still needed to determine the entire biofunctionality of goat’s milk and provide milk producers with options to increase market and added value of their products.
 Findings/conclusions: Both, Alpina and Toggenburg goat’s milk showed a high Biofunctional potential due to their fat and protein fractions; The fact that biofunctionality can be transferred to derivatives such as yogurt or cheese may increase producers' interest in producing and commercializing it, since the products can be marketed as “functional foods”.

Effect of non-thermal processing on nutritional and functional properties of milk and milk products- A review

Effect of non-thermal processing on nutritional and functional properties of milk and milk products- A review

High Hydrostatic Pressure Induced Changes in the Physicochemical and Functional Properties of Milk and Dairy Products: A Review.

High-pressure processing (HPP) is a nonthermal technology used for food preservation capable of generating pasteurized milk products. There is much information regarding the inactivation of microorganisms in milk by HPP, and it has been suggested that 600 MPa for 5 min is adequate to reduce the number of log cycles by 5–7, resulting in safe products comparable to traditionally pasteurized ones. However, there are many implications regarding physicochemical and functional properties. This review explores the potential of HPP to preserve milk, focusing on the changes in milk components such as lipids, casein, whey proteins, and minerals, and the impact on their functional and physicochemical properties, including pH, color, turbidity, emulsion stability, rheological behavior, and sensory properties. Additionally, the effects of these changes on the elaboration of dairy products such as cheese, cream, and buttermilk are explored.

A comparative study on the effects of boiling and ultrasonication on radical scavenging activity, casein particle size, and whiteness of milk

Background and Aim:Different processing treatments affect the functional properties of milk. This study aimed to evaluate the effects of boiling and ultrasonication on radical scavenging activity, micellar casein particle size, and the whiteness of milk.Materials and Methods:Milk was subjected to boiling and ultrasonication treatments. Then, the micellar casein size and the whiteness of the milk were evaluated using L-Value- intensity of whiteness and the radical scavenging capacity of the milk was evaluated using 1,1-diphenyl-2-picrylhydrazyl method.Results:The radical scavenging activity of the milk was found to be reduced during the different processing treatments, but this decrease was non-significant for the ultrasonication treatment (p>0.05). However, a significant reduction in radical scavenging activity (p<0.05) was observed for the boiled milk. Micellar casein size reduction was observed after both treatments, and boiling had a significant effect (p<0.05) on the micellar casein particle size. We found that the whiteness of skim milk was significantly decreased after boiling treatment, but was not significantly decreased after ultrasonication. Ultrasonication had a non-significant effect on the whiteness of ultrasonicated milk which was observed.Conclusion:Ultrasonicated milk had a very non-significant effect on the antioxidant activity (radical scavenging activity) of milk, whereas the effect of boiling was significant. Ultrasonication treatment increases the shelf-life of milk while retaining its bioactive properties.

Compositional and functional properties of milk and dairy products derived from cows fed pasture or concentrate-based diets.

Worldwide milk production is predominantly founded on indoor, high-concentrate feeding systems, whereas pasture-based feeding systems are most common in New Zealand and Ireland but have received greater attention recently in countries utilizing conventional systems. Consumer interest in 'pasture-fed' dairy products has also increased, arising from environmental, ethical, and nutritional concerns. A substantial body of research exists describing the effect of different feeding strategies on the composition of milk, with several recent studies focusing on the comparison of pasture- and concentrate-based feeding regimes. Significant variation is typically observed in the gross composition of milk produced from different supplemental feeds, but various changes in the discrete composition of macromolecular components in milk have also been associated with dietary influence, particularly in relation to the fatty acid profile. Changes in milk composition have also been shown to have implications for milk and dairy product processability, functionality and sensory properties. Methods to determine the traceability of dairy products or verify marketing claims such as 'pasture-fed' have also been established, based on compositional variation due to diet. This review explores the effects of feed types on milk composition and quality, along with the ultimate effect of diet-induced changes on milk and dairy product functionality, with particular emphasis placed on pasture- and concentrate-based feeding systems.

Characterization of the physical, microbiological, and chemical properties of sonicated raw bovine milk

Innovative processing technologies, such as ultrasonication, can change the properties of milk, allowing for the improvement or development of dairy foods. Yet taking bench-scale equipment to pilot plant scale has been challenging. Raw milk, standardized to 3% fat and warmed to inlet temperatures of 42 or 54°C, was exposed to continuous, high-intensity, low-frequency ultrasonication (16/20 kHz, 1.36 kW/pass) at flow rates of 0.15, 0.30, and 0.45 L/min that resulted in resident times within the reaction cell of 6, 3, and 2 min per pass, respectively. Multiple passes (3, 5, and 7, respectively) were required to obtain a total exposure time of 14 to 18 min. Evaluation of fat droplet sizes, enzyme coagulation properties, and microstructure of milk and milk gels, as well as determining compositional and lipid properties, were conducted to determine the potential of the ultrasound system to effectively modify milk. Laser scanning particle sizing and confocal microscopy showed that the largest droplets (2.26 ± 0.13 µm) found in raw milk were selectively reduced in size with a concomitant increase in the number of submicron droplets (0.37 ± 0.06 µm), which occurred sooner when exposed to shorter bursts of ultrasonication (0.45 L/min flow rates) and at an inlet temperature of 54°C. Ultrasound processing with milk entering at 42°C resulted in faster gelling times and firmer curds at 30 min; however, extended processing at inlet temperature of 54°C reduced curd firmness and lengthened coagulation time. This showed that ultrasonication altered protein-protein and protein-lipid interactions, thus the strength of the enzyme-set curds. Scanning electron microscopy revealed a denser curd matrix with less continuous and more irregular shaped and clustered strands, whereas transmission electron microscopy showed submicron lipid droplets embedded within the protein strands of the curd matrix. Processing at inlet temperature of 54°C with flow rates of 0.30 and 0.45 L/min also reduced the total aerobic bacterial count by more than 1 log cfu/mL, and the number of psychrophiles below the limit of detection (10 cfu/mL) for this study. Ultrasonication exposures of 14 to 18 min had minimal effect on the milk composition, fatty acid profiles, and lipid heat capacity and enthalpy. The findings show that this continuous ultrasound system, which is conducive to commercial scale-up, modifies the physical and functional properties of milk under the parameters used in this study and has potential use in dairy processing.

Development of nutricereals and milk‐based beverage: Process optimization and validation of improved nutritional properties

AbstractThe present study was conducted to develop finger millet and oats based functional beverage. The nutricereals were ground into coarse flour and blended in various proportions (90:10–50:50) to prepare the drink. The functional drink, optimized using response surface methodology, was prepared using malt‐drink (diluted formulation of finger millet: oat in the ratio 60:40) and double toned milk (40:60–60:40). The final optimized product was found to be rich in dietary fibers (1.23%) viz. β‐glucan (101.33 mg/100 mL), and the antioxidants like total polyphenols (52.33 mg/100 mL). The drink was low in fat (1.26%), cholesterol (3.10 mg/100 mL), and lactose (1.75%). Sensory acceptability of the selected beverage (7.21) was at par with the sweetened cattle milk (7.52) on a 9‐point hedonic scale. The overall cost of ready to serve drink was INR 10 (serving size 200 mL), ensuring the economic feasibility of the drink.Practical applicationsFinger millet is a rich source of calcium, iron and zinc; and oats are rich in beta‐glucan. Incorporation of finger millet and oats improve the overall functional properties of milk. The complementation of the finger millet with oats can further enhance the physical as well as the functional properties of the milk. The dietary fiber content of the nutricereal based beverage was also increased, which makes it a potential prebiotic. The drink also provides an improved way for the introduction of millets in futuristic food products.

Effects of High-Pressure Technology on the Functional Properties of Milk and Fermented Milk Products

Effects of High-Pressure Technology on the Functional Properties of Milk and Fermented Milk Products

Practical consequences of calcium addition to and removal from milk and milk products

Calcium in milk is significant for both its nutritive value and its key role in many functional properties of milk and milk products. Manipulating its concentration, particularly of the ionic form, alters the properties of the products and facilitates or hinders certain processing operations. Stability to thermal treatment is the major property affected, but several others such as gelation, coagulation and foaming are influenced by either adding or removing calcium. This article reviews the manipulation of the calcium content of several products and its practical consequences for dairy processing.

Which Milk is Fresh?

The different heat treatments to which milk is subjected and their effects on milk were reviewed. Pasteurized and UHT milk which is mislabelled as 'fresh milk' in the Philippines were compared. The commercial heat treatment processes applied to milk are: pasteurization, ultra high temperature (UHT), ultra pasteurization or super pasteurization, sterilization, and innovative steam injection (ISI). It was shown that commercial heat treatment processes alter the heat sensitive nutrients, physico-chemical and functional properties of milk. Higher amounts of lysinoalanine were found in UHT milk than in pasteurized milk. Further reduction in nutritional value of UHT milk occurs in supermarket shelves where it is kept until sold and consumed. While UHT treatment is suitable for tropical countries with high ambient temperatures and are unable to afford refrigeration during marketing and distribution, the nutritional quality of protein is very important because in these countries, protein intake is generally low due to poverty. The Philippine food regulatory agency allows the 'fresh milk' label on UHT milks marketed in the country. This practice does not properly inform the consumers about the product because such milks may have been in the supermarket shelves for 6 months or more and is therefore, no longer fresh. It also puts the locally produced fresh, pasteurized milk at a disadvantage. Although liquid milk for direct consumption is not covered by Codex commodity standards, use of terms like 'natural', 'pure', 'fresh', 'home made', and 'artisan' needs to be regulated in order to protect the consumers.

Effect of Asparagus racemosus (shatavari) extract on physicochemical and functional properties of milk and its interaction with milk proteins

The effects of interaction of Asparagus racemosus (shatavari) with milk constituents and physico-chemical and functional characteristics of milk was studied. Addition of freeze dried aqueous shatavari extract at a concentration of 1 g /100 ml of milk showed a decrease in pH, rennet coagulation time and an increase in acidity, viscosity and heat stability at maximum. The extract also imparted brown colour to milk and showed an increase in a* (redness) and b* (yellowness) values but a decrease in L* (lightness) value. Proteins in milk were modified by reaction with shatavari extract. The derivatives formed were characterized in terms of SDS-PAGE. Electrophoretic pattern of sodium caseinate and whey containing 1% shatavari herb extract did not show any difference in band pattern i.e. there was no difference in mobility based on size of the proteins, but the intensity (width) of bands differed.

Candidate genes affecting sheep and goat milk quality

The candidate gene approach is now exploited in sheep and goats, aiming to identify the molecular mechanisms, which make milks of different quality. In this paper, the relevant literature on this topic is reviewed. The most intensively analysed genes are milk protein genes, where, up to now, major effects were assessed for the α s1-casein, in both sheep and goats. For the α s2-casein, only in goats it was possible to associate the detected alleles with different casein synthesis levels: normal, low or null. For the β-casein, several variants were detected in goats, some of which are associated with a very low casein content, but extensive studies on the frequency and the effect of such variants are still to be conducted. The k-casein was thoroughly analysed at the genomic level in many breeds of goats, and 16 alleles were identified. However, no positive association of any allele with milk characteristics was so far reported. Conflicting results were obtained on the effect of β-lactoglobulin in sheep, while, in goats, variants were also extensively studied, but a positive association was found only with milk yield. Also the structure of the α-lactalbumin gene was partially investigated, but its possible effect on milk quality is still uncertain either in sheep or goats. Other candidate genes, that are being now extensively studied, are the genes encoding enzymes directly involved in fatty acid metabolism: ACACA in sheep; SCD in sheep and goats; LPL and DGAT1 in sheep, for which preliminary results of their effect on milk quality are given. The list of the studied candidate genes, that are being investigated according to their function, include FABP3, AMY, CGN, ACP6, ANAXA9, AMY2, gGH and Lactoferrin, although research on these genes is still at the beginning. It is expected, that new candidate genes will be identified by microarray analysis on total mRNA of the mammary gland, and that further field studies will be carried on, to demonstrate the association between genetic variants and milk quality. Nutritional and functional properties of milk still need to be more deeply investigated.

Effects of nutrition and management on the production and composition of milk fat and protein: a review

The composition and functional properties of cow’s milk are of considerable importance to the dairy farmer, manufacturer, and consumer. Broadly, there are 3 options for altering the composition and/or functional properties of milk: cow nutrition and management, cow genetics, and dairy manufacturing technologies. This review considers the effects of nutrition and management on the composition and production of milk fat and protein, and the relevance of these effects to the feeding systems used in the Australian dairy industry. Dairy cows on herbage-based diets derive fatty acids for milk fat synthesis from the diet/rumen microorganisms (400–450 g/kg), from adipose tissues (&lt;100 g/kg), and from de novo synthesis in the mammary gland (about 500 g/kg). However, the relative contributions of these sources of fatty acids to milk fat production are highly dependent upon feed intake, diet composition, and stage of lactation. Feed intake, the amount of starch relative to fibre, the amount and composition of long chain fatty acids in the diet, and energy balance are particularly important. Significant differences in these factors exist between pasture-based dairy production systems and those based on total mixed ration, leading to differences in milk fat composition between the two. High intakes of starch are associated with higher levels of de novo synthesis of fat in the mammary gland, resulting in milk fat with a higher concentration of saturated fatty acids. In contrast, higher intakes of polyunsaturated fatty acids from pasture and/or lipid supplements result in higher concentrations of unsaturated fatty acids, particularly oleate, trans-vaccenate, and conjugated linoleic acid (CLA) in milk fat. A decline in milk fat concentration associated with increased feeding with starch-based concentrates can be attributed to changes in the ratios of lipogenic to glucogenic volatile fatty acids produced in the rumen. Milk fat depression, however, is likely the result of increased rates of production of long chain fatty acids containing a trans-10 double bond in the rumen, in particular trans-10 18 : 1 and trans-10-cis-12 18 : 2 in response to diets that contain a high concentration of polyunsaturated fatty acids and/or starch. Low rumen fluid pH can also be a factor. The concentration and composition of protein in milk are largely unresponsive to variation in nutrition and management. Exceptions to this are the effects of very low intakes of metabolisable energy (ME) and/or metabolisable protein (MP) on the concentration of total protein in milk, and the effects of feeding with supplements that contain organic Se on the concentration of Se, as selenoprotein, in milk. In general, the first limitation for the synthesis of milk protein in Australian dairy production systems is availability of ME since pasture usually provides an excess of MP. However, low concentrations of protein in milk produced in Queensland and Western Australia, associated with seasonal variations in the nutritional value of herbage, may be a response to low intakes of both ME and MP. Stage of lactation is important in determining milk protein concentration, but has little influence on protein composition. The exception to this is in very late lactation where stage of lactation and low ME intake can interact to reduce the casein fraction and increase the whey fraction in milk and, consequently, reduce the yield of cheese per unit of milk. Milk and dairy products could also provide significant amounts of Se, as selenoproteins, in human diets. Feeding organic Se supplements to dairy cows grazing pastures that are low in Se may also benefit cow health. Research into targetted feeding strategies that make use of feed supplements including oil seeds, vegetable and fish oils, and organic Se supplements would increase the management options available to dairy farmers for the production of milks that differ in their composition. Given appropriate market signals, milk could be produced with lower concentrations of fat or higher levels of unsaturated fats, including CLA, and/or high concentrations of selenoproteins. This has the potential to allow the farmer to find a higher value market for milk and improve the competitiveness of the dairy manufacturer by enabling better matching of the supply of dairy products to the demands of the market.

Genetic polymorphism of the caprine kappa casein gene.

Polymorphism in the goat kappa casein gene was studied using the base excision sequence scanning (BESS) method and sequencing. Seven polymorphic sites, corresponding to single nucleotide transversions were detected. Three of these were silent mutations while the other four produced amino acid substitutions. The association between these polymorphic sites was investigated, which resulted in the identification of three goat kappa casein alleles, designated A, B, and C. Protocols for rapid genotyping of the C variant were developed by polymerase chain reaction-restriction fragment length polymorphism using Alw44I and BseNI restriction endonucleases. The occurrence of this allele was found to be very low in Spanish breeds but more frequent in the French Saanen goat. Further studies among different goat populations are necessary to establish the distribution of these alleles and their effects on the quality and functional properties of milk.