Detailed fatty acid profile of milk, cheese, ricotta and by products, from cows grazing summer highland pastures

A point of view on human fat olfaction - do fatty derivatives serve as cues for awareness of dietary fats?

Fat (triglycerides) consumption is critical for the survival of animals, including humans. Being able to smell fat can be advantageous in judging food value. However, fat has poor volatility; thus, olfaction of fat seems impossible. What about fatty acids that comprise fat? Humans smell and discriminate medium-chain fatty acids. However, no conclusive evidence has been provided for the olfactory sense of long-chain fatty acids, including essential acids such as linoleic acid (LA). Instead, humans likely perceive the presence of essential fatty acids through the olfaction of volatile compounds generated by their oxidative breakdown (e.g., hexanal and γ-decalactone). For some people, such scents are pleasing, especially when they come from fruit. Nonetheless, it remains unclear whether the olfaction of these volatiles leads to the recognition of fat per se. Nowadays, people often smell LA-borne aldehydes such as E,E-2,4-decadienal that occur appreciably, for example, from edible oils during deep frying, and are pronely captivated by their characteristic "fatty" note, which can be considered a "pseudo-perception" of fat. However, our preference for such LA-borne aldehyde odors may be a potential cause behind the modern overdose of n-6 fatty acids. This review aims to provide a view of whether and, if any, how we olfactorily perceive dietary fats and raises future purposes related to human fat olfaction, such as investigating sub-olfactory systems for detecting long-chain fatty acids.

Major Causes of Variation of External Appearance, Chemical Composition, Texture, and Color Traits of 37 Categories of Cheeses

Cheeses are produced by many different procedures, giving rise to many types differing in ripening time, size, shape, chemical composition, color, texture, and sensory properties. As the first step in a large project, our aim was to characterize and quantify the major sources of variation in cheese characteristics by sampling 1050 different cheeses manufactured by over 100 producers and grouped into 37 categories (16 with protected designation of origin, 4 traditional cheese categories, 3 pasta filata cheese categories, 5 flavored cheese categories, 2 goat milk categories, and 7 other categories ranging from very fresh to very hard cheeses). We obtained 17 traits from each cheese (shape, height, diameter, weight, moisture, fat, protein, water soluble nitrogen, ash, pH, 5 color traits, firmness, and adhesiveness). The main groups of cheese categories were characterized and are discussed in terms of the effects of the prevalent area of origin/feeding system, species of lactating females, main cheese-making technologies, and additives used. The results will allow us to proceed with the further steps, which will address the interrelationships among the different traits characterizing cheeses, detailed analyses of the nutrients affecting human health and sensorial fingerprinting.

Alterations in health-related fatty acids in buffalo milk after processing to traditional dairy products

Milk provides some beneficial fatty acids which in dairy processing are subjected to pasteurization and fermentation. With the aim to assess such changes, aliquot parts of milk from 12 buffaloes were pooled and processed to germinated yoghurt and brined cheese, and to non-germinated curd – the respective samples of raw and dairy material subjected to lipid analysis. The results show that in cheese positive and negative changes are generally balanced, rumenic acid decreasing and other CLAs altered but not total CLA and PUFA; omega ratio and atherogenicity index worsened to little extent, due to adverse change in n-3, myristic and lauric acid. In yoghurt and curd CLA dramatically decreased, excluding rumenic acid; but vaccenic acid increased, though total trans isomers decreased; the worsened n-6/n-3 ratio and atherogenicity index is mostly because of the adverse effect on PUFAn-3 but also on myristic and lauric acid. In all products SFA and MUFA did not change, including palmitic, stearic, and oleic acid. It can be concluded that the decrease of CLA in yoghurt and curd is partially compensated by the increase in the vaccenic acid, while cheese making altered individual isomers but not groups of beneficial acids.

Ricotta cream: classification based on moisture and fat content considering general standards for cheeses and cream cheeses

Ricotta cream though an emerging product sold in Brazil, by 2021 it has no fixed quality standards, a condition that can result in products with variable composition and properties. Additionally, there are no methods of sampling or analysis for its official control. In this context, this study investigated the physicochemical quality of five Brazilian ricotta cream brands to verify the extent of differences in the composition of this product, emphasizing the characterization and classification according to the Brazilian legislation and the Codex Alimentarius standards. Significant differences between brands concerning pH, titratable acidity, moisture, ash, fat, and fat in dry matter (FDM) were observed (P < 0.05), which were probably a result of their heterogeneous ingredient composition. According to Brazilian regulatory standards, all samples fit the "very high moisture" definition, and the brands A, B, D and E achieved the classification of "high-fat cheeses" since they contained at least 60.0% of FDM. Brand C was the only product that could be classified as a "medium fat cheese" due to having FDM values between 25.0% and 44.9%. All samples fit the Brazilian and Codex Alimentarius classification for "cream cheeses" based on their moisture, dry matter content, moisture on a fat-free basis and FDM. The results reinforce the need for regulatory standards regarding the physicochemical quality and composition of this cheese variety, to guarantee more transparency for the consumers and that they have access to more homogeneous products.

Physicochemical Composition, Antioxidant Status, Fatty Acid Profile, and Volatile Compounds of Milk and Fresh and Ripened Ewes' Cheese from a Sustainable Part-Time Grazing System

We conducted the first nutritional analysis of dairy products from the traditional Roja Mallorquina sheep breed. Samples of bulk raw milk were taken twice a month from December 2015 to March 2016 from sheep fed using a part-time grazing system, and fresh soft (FC, n = 8) and ripened (RC, n = 8) cheeses were made. The variability in vitamins, total phenolic compounds (TPC), total antioxidant capacity (TAC), and fatty acid (FA) content was influenced by the cheese-making process (differences between the cheese and the original milk) and by the type of cheese-making technology (mainly related to heating, the use of starter culture, and ripening). The most notable physicochemical characteristic of the cheeses was low fat content (24.1 and 29.6 g/100 g for FC and RC). Milk and RC were characterised by major concentrations of retinol (211.4 and 233.6 μg/100 g dry matter (DM), respectively) and TPC (18.7 and 54.6 μg/100 g DM, respectively), while FC was characterised by major concentrations of retinol (376.4 μg) and α-tocopherol (361.7 μg). The fat-soluble components of the FC generally exhibited better nutritional value for human health than those of the milk and RC, with a higher level of retinol and α-tocopherol; lower values for saturated FA, atherogenic, and thrombogenic indices; and higher levels of monounsaturated FA, polyunsaturated FA, n-3, and n-6. Acids, alcohols, and ketones comprised almost 95% of the volatile compounds detected. Acetoin and products of lactose and citrate metabolism played an important role in the development of the aromatic attributes of both kinds of cheese. This preliminary study can contribute to add value to these traditional products according to healthy nutritional criteria and supports the implementation of strategies to promote their commercialisation and obtain product labelling as “pasture-fed” or specific marks.

Chemometric Analysis of Fatty Acids Profile of Ripening Chesses

The number of different types of cheese worldwide exceeds 4000 and dairy fat, composed of about 400 fatty acids (FA), is one of the most complex dietary fats. Cheeses are valuable sources of different bioactive FA, i.e., conjugated FA (CFA). The aim of present study was to determine FA profile of commercially available ripening cheeses, with the special emphasis on CFA profile. Multivariate analyses (cluster analysis (CA), principal component Analysis (PCA), and linear discriminant analysis (LDA)) of chromatographic data have been proposed as an objective approach for evaluation and data interpretation. CA enabled the differentiation of ripening cheeses from fresh cheeses and processed cheeses. PCA allowed to differentiate some types of ripening cheese whereas proposed LDA model, based on 22 analyzed FA, enabled assessing cheeses type with average predictive sensitivities of 86.5%. Results of present study clearly demonstrated that FA and CFA content may not only contribute to overall nutritional characteristics of cheese but also, when coupled with chemometric techniques, may be used as chemical biomarkers for assessing the origin and/or the type of ripening cheeses and the confirmation of their authenticity, which is of utmost importance for consumers.

Effect of forage brassicas in dairy cow diets on the fatty acid profile and sensory characteristics of Chanco and Ricotta cheeses

In humid temperate regions, forage turnip (Brassica rapa ssp. rapa) and forage rape (Brassica napus ssp. biennis) are common fodder crops used for dairy cattle during the summer season. However, there is little scientific information regarding the use of brassicas and their effect on the fatty acid (FA) profile in blood, milk, and milk products. The aim of this study was to evaluate the effect of forage brassica supplementation in dairy cows on the FA profile of blood plasma, milk, and cheese, and on the sensory characteristics of Chanco and Ricotta cheeses. Twelve multiparous dairy cows (Holstein Friesian) were housed and submitted to a 3 × 3 replicated (n = 3) Latin square design with 3 treatments (control, turnip, or rape) in 3 periods of 21 d each (14 d of diet adaptation and 7 d of measurements). The control diet consisted of 16.20 kg of grass silage (Lolium perenne), 2.25 kg of soybean bran, and 2.25 kg of commercial concentrate, all on a dry matter (DM) basis. In the treatments with forage brassicas, 24.15% of the total DM was replaced by turnip or rape; thus, they consisted of 12.25 kg of silage, 2.25 kg of soybean bran, 1.2 kg of concentrate, and 5 kg of turnip or rape (DM basis). A principal components analysis was performed on the results of the cheese sensory evaluation. Supplementation with turnip or rape modified the profile of FA in blood plasma and milk, increasing the saturated fraction, mainly short- and medium-chain FA, and decreasing the mono- and polyunsaturated FA. In the sensory evaluation, diet did not affect any of the 18 attributes evaluated. However, in the principal components analysis, cheeses made with milk from animals fed turnip and rape were differentiated by increased odor, flavor, spiciness, bitterness, and acidity. Overall, brassicas can be used as an alternative forage source with no negative effects on sensory characteristics of cheeses.

Enteric Methane Emissions of Dairy Cows Predicted from Fatty Acid Profiles of Milk, Cream, Cheese, Ricotta, Whey, and Scotta

Enteric methane emissions (EME) of ruminants contribute to global climate change, but any attempt to reduce it will need an easy, inexpensive, and accurate method of quantification. We used a promising indirect method for estimating EMEs of lactating dairy cows based on the analysis of the fatty acid (FA) profile of their milk. The aim of this preliminary study was to assess milk from four single samplings (morning whole, evening whole, evening partially skimmed, and vat milks) as alternatives to reference whole milk samples from two milkings. Three fresh products (cream, cheese, and ricotta), two by-products (whey and scotta), and two long-ripened cheeses (6 and 12 months) were also assessed as alternative sources of information to reference milk. The 11 alternative matrices were obtained from seven experimental cheese- and ricotta-making sessions carried out every two weeks following the artisanal Malga cheese-making procedure using milk from 148 dairy cows kept on summer highland pastures. A total of 131 samples of milk, dairy products, and by-products were analyzed to determine the milk composition and to obtain detailed FA profiles using bi-dimensional gas-chromatography. Two equations taken from a published meta-analysis of methane emissions measured in the respiration chambers of cows on 30 different diets were applied to the proportions of butyric, iso-palmitic, iso-oleic, vaccenic, oleic, and linoleic acids out of total FAs to predict methane yield per kg of dry matter ingested and methane intensity per kg of fat and protein corrected milk produced by the cows. Methane yield and intensity could be predicted from single milk samples with good accuracy (trueness and precision) with respect to those predicted from reference milk. The fresh products (cream, cheese and ricotta) generally showed good levels of trueness but low precision for predicting both EME traits, which means that a greater number of samples needs to be analyzed. Among by-products, whey could be a viable alternative source of information for predicting both EME traits, whereas scotta overestimated both traits and showed low precision (due also to its very low fat content). Long-ripened cheeses were found to be less valuable sources of information, although six-month cheese could, with specific correction factors, be acceptable sources of information for predicting the methane yield of lactating cows. These preliminary results need to be confirmed by further study on different dairy systems and cheese-making technologies but offer new insight into a possible easy method for monitoring the EME at the field level along the dairy chain.

Effects of Summer Transhumance of Dairy Cows to Alpine Pastures on Body Condition, Milk Yield and Composition, and Cheese Making Efficiency

Simple Summary

Summer transhumance of dairy cows is a seasonal pastoral system practiced in many European countries from ancient times. This practice provides additional forage supply for mountain dairy farms and plays a role in the preservation of landscape, biodiversity, and natural habitats and conservation of local traditional dairy products, but it may affect cows’ physiological and nutritional status. This study aimed to investigate the effects of transhumance of Brown Swiss cows to summer pastures on the yield, composition, and coagulation properties of milk, and on cheese yield. For this study, twelve multiparous cows from a mountain lowland permanent farm were divided into two groups of six cows: One group stayed at the permanent farm while the other moved to the alpine pasture (1860 m above sea level). Cows at the alpine pasture had reduced milk yield and body condition, and greater fat and lower protein contents in milk compared to cows at the permanent farm. Conversely, neither milk coagulation properties nor cheese yield were affected by summer transhumance. In conclusion, summer transhumance did not affect the cheese making efficiency of milk compared to permanent farm, but the negative effect on milk yield depressed daily cheese yield, which was 2 kg/d lower in cows moved to Alpine pasture.

Abstract

Summer transhumance to alpine pastures (ALP) is widespread in dairy systems of alpine regions. This study aimed to investigate the effects of transhumance of Brown Swiss cows to ALP on the yield, composition, and coagulation properties of milk (MCP), and on cheese yield (CY). The study involved 12 multiparous cows kept at a mountain lowland permanent farm (PF), which were divided into two equal groups: One remained at the PF, the other was moved to the ALP (1860 m above sea level) from July to September. Every month (June to October), daily milk yield (MY) and body condition score (BCS) were recorded, and individual milk samples (n = 60, 2000 mL each) were collected to assess milk composition, MCP, and CY. Compared with PF, ALP cows had a reduced MY and BCS, which was maintained on return to the PF, greater fat and lower protein contents of milk. Neither MCP nor CY were affected by summer transhumance. In conclusion, summer transhumance did not affect the cheese making efficiency of milk but depressed MY and consequently daily cheese yield, which was nearly 2 kg/d lower for the ALP than the PF cows and was only partially recovered after returning to the PF in autumn.

Total and Free Fatty Acids Analysis in Milk and Dairy Fat

Dairy fat is one of the most complex natural fats because of its fatty acid (FA) composition. Ruminant dairy fat contains more than 400 different FA varying in carbon chain length, and degree, position and configuration of unsaturation. The following article reviews the different methods available to analyze FA (both total and free) in milk and dairy products. The most widely used methodology for separating and analyzing dairy FA is gas chromatography, coupled to a flame ionization detector (CG-FID). Alternatively, gas chromatography coupled to a mass spectrometer (GC-MS) is also used. After lipid extraction, total FA (TFA) are commonly converted into their methyl esters (fatty acid methyl esters, FAME) prior to chromatographic analysis. In contrast, free FA (FFA) can be analyzed after conversion to FAME or directly as FFA after extraction from the product. One of the key questions when analyzing FAME from TFA is the selection of a proper column for separating them, which depends mainly on the objective of the analysis. Quantification is best achieved by the internal standard method. Recently, near-infrared spectroscopy (NIRS), Raman spectroscopy (RS) and nuclear magnetic resonance (NMR) have been reported as promising techniques to analyze FA in milk and dairy products.

Evaluation of autochthonous lactic acid bacteria as starter and non-starter cultures for the production of Traditional Mountain cheese

Lactococcus lactis subsp. lactis 68, Streptococcus thermophilus 93 and Lactobacillus rhamnosus BT68, previously isolated from Traditional Mountain (TM) cheese, were tested for the production of four experimental mountain cheeses, with the aim to assess their effectiveness in leading the TM-cheese-making process. Lactococcus lactis subsp. lactis 68 and Streptococcus thermophilus 93 were used as starter cultures, whereas Lactobacillus rhamnosus BT68 was used as non-starter culture. Three control (CTRL) cheeses were manufactured without adding any starter, according to the traditional cheese-making process; nine, cheeses were produced inoculating the vat milk with the starters (ST), starter and low concentration of non-starter culture (STLC), starter and high concentration of non-starter culture (STHC). Samples of vat milk, cheese after 24 h and 7 months ripening were processed for microbiological counts. Mesophilic cocci were dominant in all 24 h-cheese samples, while a dominance of both cocci and lactobacilli was observed after 7 months ripening. The total genomic DNA was extracted, and a fragment of V1-V3 region was amplified and pyrosequenced. Lactococci and streptococci were the most abundant species, and Lc. lactis ssp. lactis 68 affected the proliferation of milk-resident Lc. lactis ssp. cremoris, during the early fermentation. Lb. rhamnosus BT68 showed to be responsible in reducing the abundance of other Lactobacillus species. Moreover, it likely competed against Sc. thermophilus 93 for the same energetic sources, when added in concentration higher than 5 × 10³ CFU/mL milk. The sensorial and fatty acid (FA) composition analysis were performed on cheese samples at the end of ripening, demonstrating that the inoculated cheeses had better sensorial characteristics (aspect, smell, taste, texture) than CTRL cheeses, and that Lb. rhamnosus BT68 at high concentration is related to the increase of short chain fatty acids and conjugated linoleic acid in cheese after 7 months ripening.