Mina Martini

The Macrostructure of Milk Lipids: The Fat Globules.

The aim of this review article is to summarize the information available related to milk fat globules (MFGs) in order to highlight their contribution to the nutritional and technological characteristics of milk and dairy products. The macrostructure of milk lipids is composed of globules made up of triglycerides with different melting points, enveloped by a biological membrane from the mammary epithelial cell. In milks of different animal species, there are different-sized MFGs, ranging from diameters of less than 0.2 μm to a maximum of 15 μm. The average diameter and the number of globules are affected by endogenous, physiological, and exogenous factors. The size of the globules in turn affects the qualitative characteristics of milk and cheese. In addition, the average diameter of the globules and their surface that is exposed to the digestive system affect fat digestibility in different ways. Finally, the components of the MFG membranes have been shown to take part in the secretion process of globules and to have a beneficial effect on human health. In conclusion, by acting on factors influencing the dimensions of the fat globules and by increasing the content of the milk membrane could help adapt milk production to specific consumer targets and improve milk nutritional properties.

Detection and genotyping of Toxoplasma gondii DNA in the blood and milk of naturally infected donkeys (Equus asinus).

BackgroundToxoplasma gondii is a worldwide zoonotic protozoan. Consumption of raw milk from infected animals is considered a risk factor for acquiring toxoplasmosis in humans. Recently, donkey milk has been indicated for therapeutic and nutritional purposes and T. gondii infection is common in donkeys. The purpose of the present paper was to detect the presence of parasite DNA in milk of T. gondii positive donkeys.FindingsAntibodies to T. gondii were found in 11 out of 44 healthy lactating donkeys by IFAT. T. gondii DNA was detected by PCR in blood of 6 and milk of 3 seropositive jennies. Results of limited RFLP-PCR genotyping indicated the presence of T. gondii genotype II or III, commonly found in Europe.ConclusionsThe occurrence of T. gondii DNA in milk suggests that the consumption of raw milk from seropositive donkeys could be a potential source of human infection.

Amiata donkeys: fat globule characteristics, milk gross composition and fatty acids

Amiata donkeys are a native breed reared in central Italy. Safeguarding native donkey breeds represents an opportunity for the development of marginal areas, especially given that donkey milk is now appearing on the market due to its potential benefits for human health. To date, only a few studies have focused on the characteristics of the milk fat globules (MFGs) in the donkey species. The aim of this study was to assess the morphometric characteristics of the fat globules, gross composition and fatty acid classes in milk from Amiata donkeys reared according to the typical farming and feeding systems of the area of origin. Individual milk samples, collected from 28 Amiata donkeys between 90 and 150 days of lactation, showed the following average composition (g/100 mL): 9.47 dry matter, 1.63 protein, 0.78 casein, 0.53 fat, 7.12 lactose, and 0.36 ash. The unsaturated:saturated fatty acids ratio in milk was close to 1. The percentage of short chains was 12.29, and the percentage of long chain fatty acids was 47.64. The donkey MFGs showed an average diameter of 1.92 μm, and a number of 2.18*109/mL. Regarding MFG distribution, 70% of the globules donkey of milk are smaller than 2 μm. In conclusion, the gross composition and fatty acids of Amiata donkey milk showed similarities with milk from other Italian donkey breeds, with the exception of the monounsaturated fatty acid values which were slightly higher. Donkey MFGs had a smaller diameter and were fewer than in the ruminant species.

Effect of forage:concentrate ratio on the quality of ewe's milk, especially on milk fat globules characteristics and fatty acids composition.

The aim of this study was to evaluate the milk quality of Massese ewes receiving diets with different forage:concentrate ratios (FC ratio), specially on milk fat globules characteristics and fatty acids composition. The diet is one of the main environmental factors that influence the lipidic content of milk. A trial was carried out on twenty ewes, which had been subdivided into two homogeneous groups and kept indoors at 25 days post partum. The experiment lasted 60 days, from 40 to 100 days post partum and the animals were fed two diets that differed in terms of the FC ratio: 60:40 and 40:60, as fed. The results obtained in this study showed that a greater proportion of forage, compared with an higher percentage of concentrate, led to an increase in the percentage of fat (+8.66%) and to a decrease in the percentage of milk fat globules with a size between 2 and 5 microm (-17.32%). However, the average diameter was not affected. There was also a decrease in the percentages of some medium chain fatty acids (C12:0, C14:0; -14.89% and -4.03 respectively) and an increase in mono and polyunsaturated ones such as trans11-C18:1 (+31.71%), total CLA (+22%), EPA (+18.18%) and DHA (+66.67%). In conclusion, a greater proportion of forage seem to improve the milk fatty acid profile by the increase of some fatty acid identified has being beneficial for human health.

Cheese making aptitude and the chemical and nutritional characteristics of milk from Massese ewes

Abstract The purpose of this study was to determine the effects of season, locality and the different altitudes at which farms are located, on the physico-chemical composition, morphometric characteristics of fat globules, fatty acid composition and cheese making aptitude of milk of Massese ewe’s raised in 11 flocks from two provinces of north-west Tuscany (Massa Carrara and Lucca). The winter lactation shows higher percentages of casein, lactose and not fat dry matter (P≤0.01); curd firming time (k20) is significantly lower and there is a greater curd firmness (a30) (P≤0.01); while in the summer there is a higher percentage of lipids (P≤0.01). The effect of the season significantly influences (P≤0.01) the size of the fat globules and impacted significantly on the fatty acids composition of the milk. In the hills the milk has a higher percentage of dry matter, protein, casein, fat, phosphorous and not fat dry matter (P≤0.01), whereas it has a lower percentage of lactose and calcium (P≤0.05). The Somatic Cell Count (SCC) and the Total Bacterial Count (TBC) are statistically greater on the plains (P≤0.01), while milk produced in the hills shows higher quantity of α-linolenic acid and lower saturated fatty acids (P≤0.05). In the two typical rearing areas for Massese ewes we found differences amongst dry matter, fat, phosphorous and SCC, higher (P≤0.01) in the province of Massa Carrara that also had the best rheological parameters, but we found the highest cheese yield (P≤0.05) in the province of Lucca where there are also the greatest weight loss (P≤0.01). The milks produced in the winter season and in hilly areas present the best physico-chemical and nutritional characteristics. However, we found that the technological side should be improved by diversifying cheese-making techniques in relation to the characteristics of milk. In fact, currently these techniques do not fully exploit the potential to transform those milks with the best qualitative characteristics.

Amiata donkey milk chain: animal health evaluation and milk quality

This study presents an investigation of Amiata donkey health and quality of milk for human consumption. Thirty-one lactating dairy jennies were examined. The following samples were collected: faecal samples from the rectum of animals for parasitological examination; cervical swabs for the detection of bacteria causing reproductive disorders; and blood samples for serological diagnosis of main zoonotic (Brucella spp., Leptospira spp.) and donkey abortion agents (Brucella spp., Leptospira spp., Salmonella abortus equi, Equine viral arterithis virus, Equine herpesvirus type 1). In addition, individual milk samples were collected and analysed for mastitis-causing pathogens and milk quality. Regarding animal health, we detected a high prevalence of strongyle parasites in donkeys. It is very important to tackle parasitic diseases correctly. Selective control programmes are preferable in order to reduce anthelmintic drug use. For dairy donkeys, withdrawal periods from anthelmintic drugs need to be carefully managed, in accordance with EU and national regulations. The isolation of Staphylococcus aureus in milk highlights the importance of preventing contamination during milking, by adopting appropriate hygiene and safety practices at a farm level. Lysozyme activity was high compared to cow’s milk, contributing to the inhibitory activity against certain bacteria. Donkey milk was characterised by high lactose content, low caseins, low fat, higher levels of unsaturated fatty acids compared to ruminant milks. Unsaturated fatty acids and omega 3 fatty acids in particular have become known for their beneficial health effect, which is favourable for human diet. These characteristics make it suitable for infants and children affected by food intolerance/allergies to bovine milk proteins and multiple food allergies as well as for adults with dyslipidemias. It is also recommended to prevent cardiovascular diseases.

Short communication: Monitoring nutritional quality of Amiata donkey milk: Effects of lactation and productive season

Milk nutritional characteristics are especially interesting when donkey milk is aimed at consumption by children and the elderly. The aim of this study was to monitor the nutritional quality of Amiata donkey milk during lactation and productive season to provide information on the milk characteristics and to study action plans to improve milk yield and quality. Thirty-one pluriparous jennies belonging to the same farm were selected. Individual samples of milk from the morning milking were taken once per month starting from the d 30 of lactation until d 300. Milk yield and dry matter, fat, and ash content were constant throughout the experimental period. Milk total protein content showed a progressive decrease during the first 6 mo of lactation; after this period, the protein percentages remained constant (1.50%). Caseins and lactose were lower until d 60 of lactation and remained constant thereafter. During summer and autumn, milk yield and casein and lactose contents were higher, whereas during the spring season, higher protein and ash contents were found. The percentages of fat and dry matter were stable as were most of the minerals in the milk, except for calcium, which was higher in the spring. In conclusion, Amiata donkey milk was found to be relatively stable during lactation. This is an advantage in terms of the production and trade of a food product with consistent characteristics. The different milk yield and quality during the productive seasons were probably related to better adaptability of the animals to warm and temperate periods.

Faba bean (Vicia faba minor) and pea seeds (Pisum sativum) as protein sources in lactating ewes’ diets.

Abstract 18 Massese lactating ewes, divided into 3 homogeneous groups for parity and milk yield, were used to evaluate the replacement effects of soybean meal by Faba bean (Vicia faba minor) and Pea (Pisum sativum) seeds. During a 70 days trial (beginning after weaning: 30±1.5 days after lambing) animals were fed three isonitrogenous and isocaloric diets. Each diet was characterised by the presence of only one protein feed. The diets consisted of alfalfa hay (1.1 kg/head/d) and a decreasing amount of mixed feed (from 1.1 to 0.7 kg/head/d) to fit animals’ requirements. Milk yield, milk chemical composition, animals live weight and BCS, health state and hematochemical parameters were regularly monitored. No diets palatability problems were detected. No significant differences resulted for live weight, BCS, milk yield and milk chemical composition, except for milk protein: higher for faba bean (6.54%) and soybean (6.39%) respect pea (5.66%) diets, P<0.05. No differences resulted for blood parameters too and no clinical signs of illness were observed. Therefore faba bean and pea seeds seem to be able to replace the soybean well.

Genetic variability of the ovine αs1-casein

Riassunto Variabilità genetica dell’αs1-caseina ovina. La variabilità genetica dell’ αs1-caseina ovina è stata valuta con particolare attenzione alla presenza delle varianti A, C, e D e del polimorfismo nell’esone 17 che determina una transizione T →C a cui corrisponde la sostituzione aminoacidica Ile186 →Thr186. La variante C è stata suddivisa in due tipi, C’ e C’’, in base all’aminoacido presente in posizione 186. L’aplotipo ancestrale è C’ (Pro13-Ser68-Thr186) mentre C’’ (Pro13-Ser68-Ile186) è risultato il più frequente in 5 razze ovine italiane.

Morphometric analysis of fat globules in ewe's milk and correlation with qualitative parameters

Abstract In this study the morphometric characteristics of fat globules from ewe’s milk have been correlated with the chemical and technological parameters of the milk. Milk samples were taken from twenty-five Massese ewes, subdivided according to the parity; the animals were homogeneous for lactation phase and diet. The morphometric analysis of fat globules (n./ml, diameter, surface area/volume), the standard chemical analysis, SCC and determination of the rheological parameters were performed on milk samples obtained during the morning milking. The mean number of fat globules/ml was 3.09 x 109, with a mean diameter of 3.93 µm, ranging from 1.20 µm to 12.30 µm. For all parities, a fat globule diameter ranging from 3.21 to 4.20 µm was found most frequently. Animals in the first lambing order showed a significantly lower percentage (5.26%) of large globules (>5.21µm), while animals in the fifth lambing order showed a higher percentage (20.75%). The number of globules/ml was negatively correlated to milk production (P≤0.01) and curd firmness at 45 min (P≤0.05); whereas it was positively correlated to protein content, non-fat dry matter, and curd firming time (P≤0.05). Fat globule dimensions varied according to the parity of the animals and influenced various qualitative parameters of the milk.