Dairy, Volume 4, Issue 3 (September 2023) – 10 articles

This work analyzed the antidiabetic activity of peptides from whey proteins after hydrolysis by Lactobacillus rhamnosus GG and Streptococcus thermophilus SY-102, emphasizing the differences between the proteolytic systems of both bacteria. Peptide fractions from whey proteins may have biological functions, such as antidiabetic functions, which inhibit the DPP-IV enzyme, and lactic acid bacteria could release them. A whey solution of 10% was fermented with selected lactic acid bacteria in monoculture and coculture, analyzing kinetic parameters and the proteolytic profile, using the 2,4,6-trinitrobenzene sulfonic acid technique for free amino groups’ determination and Tris-tricine polyacrylamide gel electrophoresis. An in vitro inhibition assay of the DPP-IV enzyme was used. The kinetic parameters showed a faster duplication rate in the monoculture with L. rhamnosus GG than in the co-culture, which was related to lactic acid production. Co-culture does not have the highest production of free amino groups and peptides. Still, peptide fractions with lower molecular weight (<2 kDa) were found and showed a high DPP-IV inhibitory capacity that was maintained from the middle of the fermentation to the end (55.4%). In comparison, the monoculture of L. rhamnosus GG increased from 0 to 63.3%. This demonstrates that the proteolytic capacity and the proteolytic system of each lactic acid bacteria determine the structure of the released peptides. Full article

Cheese and milk are stapled dairy products consumed globally. However, adulterants in these products pose significant health risks and compromise their quality. Analytical techniques are crucial in detecting and quantifying adulterants to combat adulteration. This opinion explores the problem of cheese and milk adulteration, highlights the role of spectroscopic techniques (fluorescence spectroscopy, nuclear magnetic resonance (NMR) spectroscopy, and infrared (IR) spectroscopy) in adulteration detection, and compares their effectiveness with the well-established high-performance liquid chromatography (HPLC) method. The advantages and limitations of each technique are discussed, providing valuable insights into their applications to ensure the authenticity and safety of cheese and milk products. Full article

Essential oils are bioactive compounds, originating from the secondary metabolism of plants, recognized for their ability to modify rumen fermentation, gut health, and to function as antioxidant molecules in small ruminants. Indeed, small ruminant-derived products, such as milk, dairy, and meat can benefit from the utilization of essential oils, that have demonstrated antimicrobial, antioxidant and anti-inflammatory affects, in the animals’ diet. This review reports on the findings that demonstrates the possible role of essential oils in controlling greenhouse gas emissions from ruminants through the modulation of ruminal microbial populations, in sustaining animal health and welfare by affecting the gut microbiota, and in ameliorating animals’ products through enhancement of their nutritional composition from a human diet perspective. However, the current review highlighting the inconclusive findings related to the use of essential oils in small ruminant nutrition, supports the need of further studies to better understand the administration of how essential oils and to explore their specific actions at the molecular level. Full article

A study was undertaken on milk and caciocavallo cheese from Podolica cattle in the Basilicata Region (Southern Italy), with a view of the possible identification of specific traits useful to protect them from imitations. More than 800 individual milk samples and 29 bulk milk samples were taken in spring–early summer from cows registered in the genealogical book of the breed; moreover, 18 samples of caciocavallo cheese were taken in the same geographical area, 9 of which had been manufactured from Podolica milk. The obtained results confirmed the high aptitude of Podolica milk to cheesemaking, even though the exceptional dry weather in the period of sampling decreased the fat content with respect to the literature data. The presence of the variant A of α-lactalbumin, a characteristic trait of Podolica milk, was ascertained in only 14% of the animals considered in the study, indicating that this feature is disappearing in the population under study. The results on caciocavallo gave useful indications, because some possible peculiar characteristics were identified, such as the lower protein to fat ratio and some aroma descriptors. More research is needed to assess if these characteristics can be used for developing a multi-functional protocol, to be extended to all Italian Podolica populations, able to discriminate the cheese from imitations. In this perspective, the application of selection strategies for increasing the frequency of the variant A of α-lactalbumin should be carefully evaluated. Full article

Dairy proteins are potential and multipurpose ingredients used to prepare various food products. It exhibits many beneficial functionalities and bioactivities in the processing of food products. All the functionalities of different dairy proteins depend on their peculiar structural characteristics. So, the present study aimed to characterize high-protein powders with different matrices (milk protein concentrate (MPC), rennet casein (RCN), micellar casein concentrate (MCC), whey protein isolate (WPI), and native whey concentrate (NWC)) for their composition, handling, and reconstitution properties, and microstructure and compared them with whole milk powder (WMP) and skim milk powder (SMP). The bulk density of the high-protein powders was significantly (p < 0.05) lower than WMP and NFDM. Due to the low bulk density of the high-protein powders, the wettability of these powders in the water was very high. Microstructural analysis of powders by scanning electron microscopy reveals that the high-protein powder had tetrahedron-to-polyhedron-shaped particles depending on the protein level. The idea regarding the powder’s morphology might be helpful for further improvement in the production processes to modify the functional properties of high-protein milk powders. Full article

In this study, the microbiological quality of traditionally fermented milk from Northern Uganda and Western Kenya was analysed. Six samples of typical traditionally fermented milk were collected randomly from traditional cattle keepers in Karamojong (UG 1) and Acholi (UG 2) in Northern Uganda and Kalenjin in Western Kenya (KE). The microbial quality of the collected samples was assessed through the use of conventional methods for total aerobic mesophilic bacteria, total coliform, lactic acid bacteria, Staphylococcus aureus, Listeria monocytogenes, yeasts, and mould counts. The mean aerobic mesophilic bacterial counts were 5.14 × 10⁹ coliform forming units (cfu)/mL. The mean counts for mesophilic lactobacilli ranged from 10⁶ to 10⁸ cfu/mL. The mean thermophilic lactobacilli count ranged from 10⁷ to 10⁹ cfu/mL, while the mean thermophilic lactococci counts ranged from 10⁶ to 10⁹ cfu/mL. On the other hand, the Streptococci counts were between 10⁶ and 10⁸ cfu/mL. The mean count for the non-sorbitol E. coli was 3.87 × 10³ cfu/mL. These results suggest that although the pH of the traditional yoghurt in this study was low, the acidity was not sufficient to inhibit growth of microorganisms in the product. Although it is difficult to avoid the microbial contamination of milk during milking, it is of the utmost importance to maintain a very high level of hygiene in dairy farming practices, and the correct cleaning of teats during milking is very important for good udder health and optimum milk quality, and to ensure safety. The results regarding microbial contamination pose public health concerns, and therefore the appropriate government agencies must pay attention to ensure that the environment in which yoghurt is produced is in the best condition to reduce contamination. Full article

The study examined the relationship between milk yield and udder morphology traits in White Fulani cows. Fifty-eight apparently healthy cows in early lactation at 2nd, 3rd, and 4th parity were used in the study. The data obtained from the cows were test day milk yield (TDMY) from single milking and udder morphology traits comprising udder length (UL), udder width (UW), udder depth (UD), fore teat length (FTL), rear teat length (RTL), fore teat diameter (FTD), and rear teat diameter (RTD). There was no significant effect of parity on TDMY or the udder morphology traits. Phenotypic correlations between TDMY, UL, UW, and UD were positive and significant. Notably, phenotypic correlations between UL and TDMY at different parities were the strongest. Teat measurements had no significant correlation with TDMY. Stepwise and principal component regressions were implemented to assess the relationship between milk yield and udder morphology traits. Interestingly, UL was the only trait that entered the reduced models. The results suggest a probable genetic correlation between milk yield and udder length. Therefore, since udder conformation traits are heritable, when selecting for udder length in White Fulani cows, a correlated response in milk yield is expected. Full article

The objective of this three-treatment, 12-week study (involving 69 dairy cows) was to test three methods of concentrate allocation on milk production efficiency. All treatments were offered a basal mixed ration of grass silage and concentrates, with additional concentrates offered to individual cows based on either milk yield alone (Control), milk energy output (Precision 1) or energy intake and milk energy output (Precision 2). Concentrate requirements were calculated and adjusted weekly. Control cows had lower concentrate dry matter intake (DMI; p = 0.040) and milk protein content (p = 0.003) but yield of milk and energy-corrected milk (ECM), energy balance, bodyweight and condition score were unaffected by treatment. Efficiency measures such as ECM/DMI and ECM/metabolizable energy intake were also unaffected by treatment. Less concentrates were used per kg ECM yield in the Control compared to the Precision treatments (p < 0.001). In conclusion, accounting for individual cow milk composition or milk composition combined with individual cow energy intake did not improve production efficiency compared to an approach based on individual cow milk yield only. Full article

Blue cheeses are those whose matrix is veined with a blue, blue-grey, or blue-green colour due to the development of Penicillium roqueforti. There are more than 45 varieties of blue cheese produced worldwide, with some distinct features, although the manufacture process is similar. In addition to P. roqueforti, complex microbial populations interact and succeed throughout the manufacturing and ripening at the cheese’s surface (the rind) and interior (matrix). The microbiota of blue cheeses is made up of a vast array of both prokaryotic and eukaryotic microorganisms. Acidification of the curd relies on the action of lactococci and other lactic acid bacteria (LAB) species. The ripened cheeses’ final quality and shelf-life properties largely depend on the enzymatic systems of the components of the microbiota, particularly on those of LAB, P. roqueforti, and yeast species. Proteolysis is the most complex and important primary biochemical process involved in blue-veined cheeses during ripening, with P. roqueforti being considered the main proteolytic agent. Lipolysis is also strong, originating, among other compounds, ketones, which are the main aroma compounds in blue-veined cheeses. In addition, several bioactive compounds are produced during ripening. The biochemical activities, mainly of microbial origin, are responsible for the sensory characteristics of these very appreciated cheese varieties worldwide. Full article

The ability to measure and capture real-time unit operational data has significant benefits during dairy processing, whether it is the basics, such as measuring temperature, pressure, and flow rates, or more recent developments in the case of in-line viscosity and product-compositional measurements. This rapid data collection has helped increase profitability by reducing energy costs, minimizing product loss, and allowing automated control. Advances in technology have allowed for in-line measurements of the composition and some physical attributes such as particle size and viscosity; however, an attribute that spans both compositional and physical attributes is pH, directly influenced by composition but also environments, such as temperature and dry matter content. pH is measured for a plethora of reasons, such as a measure of milk quality (microbial spoilage), acidification of casein, cheese production, maintaining optimum conditions during protein hydrolysis, etc. However, very little is published on the fundamentals of pH and pH measurement in dairy processing; rather, it is usually a cause-and-effect phenomenon. This review visits one of the oldest analytical considerations in the dairy industry and re-examines how it is affected by product composition and processing conditions. Full article