Fatty Acid Content, Lipid Quality Indices, and Mineral Composition of Cow Milk and Yogurts Produced with Different Starter Cultures Enriched with Bifidobacterium bifidum

This study aimed to analyze the composition of fatty acids, with particular emphasis on the content of cis9trans11 C18:2 (CLA) acid, the content of minerals, and lipid quality indices in raw milk, pasteurized milk, and in yogurts produced with selected starter cultures enriched with Bifidobacterium bifidum. The GC-FID method was used to determine the fatty acid composition of those dairy products. To analyze the contents of microelements (copper, manganese, iron, and zinc) and macroelements (magnesium, calcium) flame atomic absorption spectrometry was used. The content of phosphorus was determined with the usage of the colorimetric method and the contents of sodium and potassium with emission method. Data analysis showed that such technologies as milk pasteurization and milk fermentation had a significant impact on the fatty acid profile and contents of micro- and macroelements. The lipid quality indices: atherogenicity index (AI), index thrombogenicity (TI), hypocholesterolemic/hypercholesterolemic index (H/H), and (n − 6)/(n − 3) ratio, were at similar levels in raw and pasteurized milk and yogurts produced. Starter culture type affected the content of cis-9, trans-11 CLA C18:2 acid in yogurts. Out of the starter cultures applied in the study, only the FD-DVS YC-X16 Yo-Flex starter culture with BB-12 caused a significant (p < 0.05) increase in CLA content. The CLA content of the yogurts produced using this starter culture was 2.67 mg/g fat. In raw milk, pasteurized milk, and the second batch of yogurts, the content of cis-9, trans-11 C18:2 acid was significantly lower and reached 2.26 mg/g fat, 2.17 mg/g fat, and 2.30 mg/g fat, respectively. The study indicated that, when it comes to being a source of minerals, yogurts were better than milk. Yogurts were also characterized by significantly (p < 0.05) higher contents of all micro- and macroelements taken into account in this study than the raw milk used to produce them.

Fatty Acid Profile, Conjugated Linoleic Acid Content, and Lipid Quality Indices in Selected Yogurts Available on the Polish Market

The aim of the present study was to determine the fatty acid composition, the content of cis9trans11 C18:2 acid (CLA), and lipid quality indices in yogurts made of cow's milk, available on the Polish market. The test material consisted of: natural yogurts, natural yogurts with additives (muesli, cereal grains), bio yogurts, bio yogurts with additives (millet groats, quinoa, chestnuts), probiotic yogurts, and eco yogurts. All the products were bought in the period from May to June 2021. The conducted research showed that the analyzed yoghurts were characterized by a varying content of fatty acid groups, different values of the calculated lipid quality indices, as well as a different content of conjugated linoleic acid cis9trans11 C18: 2 (CLA). Natural yogurts with additives had the highest content of polyunsaturated fatty acids (PUFAs) and n-3 PUFAs. Natural and bio yogurts with additives had a higher content of n-6 PUF than the other analyzed yogurts. The n-6/n-3 ratio was lower in bio yogurts and eco yogurts. Natural yogurts with additives featured the lowest index of atherogenicity (AI) and index of thrombogenicity (TI) and the highest hypocholesterolemic/hypercholesterolemic ratio (H/H). The fat extracted from the bio yogurts had the highest (0.90% of total fatty acids) mean content of cis9trans11 C18:2 (CLA). In fat of the other analyzed yogurts, mean CLA content in total content of fatty acids varied from 0.48% in natural yogurts with additives to 0.81% in bio yogurts with additives.

Changes in the Folate Content and Fatty Acid Profile in Fermented Milk Produced with Different Starter Cultures during Storage

The application of bacterial cultures in food fermentation is a novel strategy to increase the “natural” levels of bioactive compounds. The unique ability of lactic acid bacteria (LAB) to produce folate, B vitamins, and conjugated linolenic acid cis9trans11 C18:2 (CLA) during cold storage up to 21 days was studied. Although some species of LAB can produce folates and other important nutrients, little is known about the production ability of yogurt starter cultures. Pasteurized milk samples were inoculated with four different combinations of commercially available yogurt vaccines, including starter cultures of Bifidobacterium bifidum. Both the type of vaccine and the time of storage at 8 °C had a significant effect on the folate and CLA contents in the tested fermented milks. The highest folate content (105.4 µg/kg) was found in fresh fermented milk inoculated with Lactobacillus delbrueckii, Streptococcus thermophilus, and Bifidobacterium bifidum. Only the mix of Lactobacillus delbrueckii subsp. bulgaricus, Streptococcus thermophilus, and Bifidobacterium bifidum showed potential (59% increase) to synthesize folate during seven days of storage. A significant increase in the content of CLA, when compared to fresh fermented milk, was observed during cold storage for up to 21 days in products enriched with Bifidobacterium bifidum.

Milk Fatty Acid Profiles in Different Animal Species: Focus on the Potential Effect of Selected PUFAs on Metabolism and Brain Functions

Milk contains several important nutrients that are beneficial for human health. This review considers the nutritional qualities of essential fatty acids (FAs), especially omega-3 (ω-3) and omega-6 (ω-6) polyunsaturated fatty acids (PUFAs) present in milk from ruminant and non-ruminant species. In particular, the impact of milk fatty acids on metabolism is discussed, including its effects on the central nervous system. In addition, we presented data indicating how animal feeding—the main way to modify milk fat composition—may have a potential impact on human health, and how rearing and feeding systems strongly affect milk quality within the same animal species. Finally, we have presented the results of in vivo studies aimed at supporting the beneficial effects of milk FA intake in animal models, and the factors limiting their transferability to humans were discussed.

The Comparison of Fatty Acid Composition and Lipid Quality Indices in Hard Cow, Sheep, and Goat Cheeses

This study aimed to evaluate the fatty acid composition, including the contents, of conjugated linoleic acid cis9trans11 C18:2 (CLA) and trans C18:1 and C18:2 isomers in hard cow, sheep, and goat cheeses found on the Polish market and to compare lipid quality indices in these cheeses. The gas chromatography method was used to determine the fatty acid profile. The study demonstrated various contents of cis9trans 11 C18:2 (CLA), trans C18:1, and C18:2 isomers and the values of lipid quality indices in the cheeses. Sheep and goat cheeses were richer sources of short-chain fatty acids (SCFA) (14.73 ± 2.55% and 14.80 ± 2.80%, respectively) than the cow cheeses (9.38 ± 0.87%). The cow cheeses had a significantly higher (p < 0.05) content of monounsaturated fatty acids (MUFA), the lowest n-6/n-3 ratio, and the highest content of fatty acids, inducing a desirable dietary effect in humans (DFA) compared to the sheep and goat cheeses. Significantly higher (p < 0.05) contents of polyunsaturated fatty acids (PUFA) were found in sheep cheeses. Goat cheeses had the highest n-3 PUFA content and the lowest values of the thrombogenicity index (TI) (2.67 ± 0.44) compared to the sheep and cow cheeses (3.14 ± 0.29 and 3.13 ± 0.13, respectively). The cow, sheep, and goat cheeses were characterized by similar values of the hypocholesterolemic/hypercholesterolemic (H/H) ratio. Sheep cheeses had the highest levels of cis9trans11 C18:2 (CLA) and the highest total content of trans C18:1 and trans C18:2 isomers. The research showed that sheep, cow, and goat cheeses offered various health benefits. The differences in fatty acid composition and the different values of the lipid quality indices found in the cheeses may be due to differences in both the composition of milk used to produce them and the cheese-making technology. Studies conducted by many authors have indicated that the feeding system of the ruminants has a significant impact on the quality and chemical composition of milk, as well as its applicability for cheese production.

Enhancing Omega-3 Long-Chain Polyunsaturated Fatty Acid Content of Dairy-Derived Foods for Human Consumption

Omega-3 polyunsaturated fatty acids (n-3 PUFA) are termed essential fatty acids because they cannot be synthesized de novo by humans due to the lack of delta-12 and delta-15 desaturase enzymes and must therefore be acquired from the diet. n-3 PUFA include α-linolenic acid (ALA, 18:3n-3), eicosapentaenoic (EPA, 20:5n-3), docosahexaenoic (DHA, 22:6n-3), and the less recognized docosapentaenoic acid (DPA, 22:5n-3). The three long-chain (≥C20) n-3 PUFA (n-3 LC-PUFA), EPA, DHA, and DPA play an important role in human health by reducing the risk of chronic diseases. Up to the present time, seafood, and in particular, fish oil-derived products, have been the richest sources of n-3 LC-PUFA. The human diet generally contains insufficient amounts of these essential FA due largely to the low consumption of seafood. This issue provides opportunities to enrich the content of n-3 PUFA in other common food groups. Milk and milk products have traditionally been a major component of human diets, but are also among some of the poorest sources of n-3 PUFA. Consideration of the high consumption of milk and its processed products worldwide and the human health benefits has led to a large number of studies targeting the enhancement of n-3 PUFA content in dairy products. The main objective of this review was to evaluate the major strategies that have been employed to enhance n-3 PUFA content in dairy products and to unravel potential knowledge gaps for further research on this topic. Nutritional manipulation to date has been the main approach for altering milk fatty acids (FA) in ruminants. However, the main challenge is ruminal biohydrogenation in which dietary PUFA are hydrogenated into monounsaturated FA and/or ultimately, saturated FA, due to rumen microbial activities. The inclusion of oil seed and vegetable oil in dairy animal diets significantly elevates ALA content, while the addition of rumen-protected marine-derived supplements is the most effective way to increase the concentration of EPA, DHA, and DPA in dairy products. In our view, the mechanisms of n-3 LC-PUFA biosynthesis pathway from ALA and the biohydrogenation of individual n-3 LC-PUFA in ruminants need to be better elucidated. Identified knowledge gaps regarding the activities of candidate genes regulating the concentrations of n-3 PUFA and the responses of ruminants to specific lipid supplementation regimes are also critical to a greater understanding of nutrition-genetics interactions driving lipid metabolism.

Enhancement of dairy sheep cheese eating quality with increased n-3 long-chain polyunsaturated fatty acids

This study investigated the effect of different plant oil-infused and rumen-protected wheat-based pellets containing eicosapentaenoic acid (EPA, 20:5n-3) and docosahexaenoic acid (DHA, 22:6n-3) on n-3 long-chain (≥C₂₀) polyunsaturated fatty acid (LC-PUFA) content, fatty acid recovery, and sensory attributes of ripened cheese from dairy sheep. During a 10-wk supplementary feeding trial, 60 dairy ewes balanced by live weight, milk yield, parity, and sire breed were randomly divided into 6 groups that were (1) supplemented with on-farm existing commercial wheat-based pellets without oil inclusion (control) or supplemented with wheat-based pellets infused with 50 mL/kg dry matter of oils from (2) canola, (3) rice bran, (4) flaxseed, (5) safflower, and (6) rumen-protected EPA + DHA. Milk samples from each treatment were collected separately by sire breed during the experimental period for cheese processing at the end of the experiment. Twelve batches of cheese (2 batches per treatment) were processed and ripened for 120 d. Three cheese samples were collected and analyzed for each cheese making session (total of 36 cheese samples) at d 120 of ripening. Processed cheese of rumen-protected EPA + DHA had the most efficiency at elevating total n-3 LC-PUFA [total EPA + DHA + docosapentaenoic acid (DPA, 22:5n-3] content compared with the control (0.49 vs. 0.28%). Flaxseed elicited the greatest enhancement of α-linolenic acid (ALA, 18:3n-3), whereas safflower was the most effective diet in enhancing the level of linoleic acid (18:2n-6) in cheese (1.29 vs. 0.71% and 4.8 vs. 3.3%, respectively). Parallel recoveries of n-3 and n-6 LC-PUFA were observed across all treatments except for α-linolenic acid and EPA. Cheese eating sensory traits were also highly affected by oil supplementation, with the highest score of 7.5 in cheese from the rice bran and flaxseed treatments. These results provide new insights into the biological mechanisms and processes that determine dairy ewe milk productivity by underpinning the vital biological role of n-3 LC-PUFA in not only enhancing the healthy composition of cheese from ewes but also translating it into consumer acceptability.

Comparing the effect of homogenization and heat processing on the properties and in vitro digestion of milk from organic and conventional dairy herds

We compared the effects of homogenization and heat processing on the chemical and in vitro digestion traits of milk from organic and conventional herds. Raw milk from organic (>50% of dry matter intake from pasture) and conventional (no access to pasture) farms were adjusted to commercial whole and nonfat milk fat standards, and processed with or without homogenization, and with high-temperature-short-time or UHT pasteurization. The milk then underwent in vitro gastrointestinal digestion. Comparison of milk from organic and conventional herds showed that the milks responded to processing in similar ways. General composition was the same among the whole milk samples and among the nonfat milk samples. Protein profiles were similar, with intact caseins and whey proteins predominant and only minor amounts of peptides. Whole milk samples from grazing cows contained higher levels of α-linolenic (C18:3), vaccenic (C18:1 trans), and conjugated linoleic acids, and lower levels of palmitic (C16:0) and stearic (C18:0) acids than samples from nongrazing cows. Processing had no effect on conjugated linoleic acid and linolenic acid levels in milk, although homogenization resulted in higher levels of C8 to C14 saturated fatty acids. Of the 9 volatile compounds evaluated, milk from grazing cows contained lower levels of 2-butanone than milk from nongrazing cows, and milk from both farms showed spikes for heptanal in UHT samples and spikes for butanoic, octanoic, nonanoic, and N-decanoic acids in homogenized samples. At the start of in vitro digestion, nonfat raw and pasteurized milk samples formed the largest acid clots, and organic milk clots were larger than conventional milk clots; UHT whole milk formed the smallest clots. Milk digests from grazing cows had lower levels of free fatty acids than digests from nongrazing cows. In vitro proteolysis was similar in milk from both farms and resulted in 85 to 95% digestibility. Overall, milk from organic/grass-fed and conventional herds responded in similar ways to typical homogenization and heat processing used in United States dairy plants and showed only minor differences in chemical traits and in vitro digestion. Findings from this research enhance our knowledge of the effect of processing on the quality traits and digestibility of milk from organic/pasture-fed and confined conventional herds and will help health-conscious consumers make informed decisions about dairy selections.

Influence of the addition of Lactobacillus acidophilus La-05, Bifidobacterium animalis subsp. lactis Bb-12 and inulin on the technological, physicochemical, microbiological and sensory features of creamy goat cheese

We evaluated the effects of addition of probiotic cultures and inulin on the quality of creamy goat cheese.

Compositional and biochemical changes in Genestoso cheese, a Spanish raw cow's milk variety, during ripening

BACKGROUND

Physicochemical characteristics, proteolysis and lipolysis were studied throughout the ripening of eight batches of a traditional Spanish variety made from raw cow's milk, in order to establish a basis for its industrial production.

RESULTS

The main compositional characteristics of this cheese after 60 days of ripening were its high proportion of total solids (TS; 752 g kg⁻¹ of cheese), an average content of protein (452.8 g kg⁻¹ TS) and fat (475.1 g kg⁻¹ TS) and the presence of residual lactose (12.5 g kg⁻¹ TS). Its pH value (4.04) was extremely low. Phosphorus (5.13 g kg⁻¹ TS) and sodium (8.29 g kg⁻¹ TS) were the most abundant mineral elements in cheese, whereas calcium levels (1.92 g kg⁻¹ TS) were very low. Proteolysis extension and depth were very low, which resulted in almost zero degradation of αs1- and β-casein. Fat acidity increased during ripening, reaching final values of 50.1 mg KOH kg⁻¹ of fat. The main free fatty acid was C16:0, followed by C18:1 and C14:0.

CONCLUSION

These results suggest that this variety undergoes a limited proteolysis and moderate lipolysis during ripening. The low pH, low calcium content and limited proteolysis led to a crumbly texture in this cheese variety.

Physiological properties of milk ingredients released by fermentation

The demand for health-promoting food ingredients rises within an increasing market worldwide. Different milks fermented with bacteria, yeasts, moulds or enzymes from animal, plant and microbial sources offer a broad range of possibilities to cover different health aspects with new bioactive components. By the fermentation process interesting ingredients are enriched and released from the matrix, like lactoferrin, micro-nutrients, CLA and sphingolipids or synthesized, such as exo-polysaccharides and bioactive peptides. In particular, milk derived bioactive peptides exert several important health-promoting activities, such as anti-hypertensive, anti-microbial, anti-oxidative, immune-modulatory, opioid and mineral-binding properties. Milk-fermentation processes with probiotic bacteria synergistically combine health supporting bacterial and milk ingredient aspects which include new therapeutic solutions concerning hypercholesterolemia, carcinogenic intoxications, treatment of diarrhea, reduction of intestine pathogens, and supporting natural immune defense. Especially, milk-proteins and associated bioactive peptides released during microbial or enzymatic fermentation of milk offer a broad spectrum of new functional properties, for instance anti-hypertensive, anti-microbial, anti-oxidative, immuno-modulatory, opioid and mineral-binding properties. This review aimed at discussing recent research activities on physiological purposes and technical process aspects of functional components from fermented milk with a specific focus on biofunctional peptides released from fermented milk proteins.

Differences in whey protein content between cow's milk collected in late pasture and early indoor feeding season from conventional and organic farms in Poland

BACKGROUND

The aim of the study was to investigate bioactive whey protein concentrations in cow's milk collected in late pasture (LP) and early indoor feeding (EIF) season from conventional and organic farms in Poland.

RESULTS

Results showed that in the LP somatic cell count (SCC) was higher under organic farming conditions. However, percentages of protein and fat were higher under conventional farming conditions. In EIF, milk from conventional dairy farms had a higher percentage of fat and lactose and a lower concentration of protein and SCC in comparison to milk from organic farms. Organic milk in LP had higher concentrations of beneficial whey proteins than conventional milk, including β-lactoglobulin (β-Lg, 4.12 vs. 2.68 g L⁻¹), lactoferrin (Lf, 334.99 vs. 188.02 mg L⁻¹), and lysozyme (Lz, 15.68 vs. 12.56 µg L⁻¹). However, conventional milk in EIF had higher concentrations of bovine serum albumin (146.47 vs. 118.65 mg L⁻¹), Lf (49 vs. 185.27 mg L⁻¹), and Lz (16.63 vs. 13.22 µg L⁻¹).

CONCLUSIONS

The results show significant differences in the investigated parameters between organic milk and milk from conventional system during EIF and LP. Moreover, extending the pasture season during EIF in organic farms decreases concentration of bioactive compounds of milk.

Especies ibéricas de los géneros <i>Lithurgus</i> Berthold, 1827, <i>Creightonella</i> Cockerell, 1908 y <i>Chalicodoma</i> Lepeletier, 1841 (Hymenoptera, Megachilidae): claves de identificación y nuevos datos de distribución

El presente trabajo, dentro de la revisión que se está realizando sobre la familia Megachilidae en la fauna ibérica, incluye las claves de identificación y aporta nuevos datos de distribución para las especies de tres géneros: Lithurgus (tres especies), Creightonella (una) y Chalicodoma (ocho). Las claves se acompañan de dibujos y fotografías ilustrativos que permiten el reconocimiento tanto de las especies como de las subespecies.

Conjugated linoleic acid (CLA) and fatty acid composition of milk, curd and Grana Padano cheese in conventional and organic farming systems

CLA levels and fatty acid composition were measured to compare the fat composition in organic bulk milk, destined to the production of Grana Padano cheese, with those produced by conventional system. The curds and Grana Padano cheeses were also analysed to evaluate the effects of the production technology on the CLA content. All analysed organic samples were characterized by higher annual means of CLA, vaccenic acid (TVA) and linolenic acid (LNA) in comparison with conventional samples (with P<0·05). Nevertheless, no particular effect of the production technology was seen on the CLA content. The animal diet appears to be the factor which has the highest effect on the CLA concentration in milk and milk products and an organic diet based on fresh or dried forage, that is rich in CLA precursory fatty acids, may improve the yield of fatty acids with beneficial effects on health.