To isolate and identify antioxidant peptides from enzymatically hydrolysed whey protein, whey protein isolate was hydrolysed by different protease (trypsin, pepsin, alcalase 2·4L, promatex, flavourzyme, protease N). The hydrolysate generated by alcalase 2·4L had the highest antioxidant activities on 1,1-diphenyl-2-picrylhydrazyl (DPPH) radicals, superoxide radicals and in a linoleic acid peroxidation system induced by Fe2+. The IC50 values of DPPH and superoxide radical scavenging activities of the hydrolysate decreased significantly (6·89 and 38·88%, respectively) after treatment with macroporous adsorption resin. Seven different peptides showing strong antioxidant activities were isolated from the hydrolysate using consecutive chromatographic methods including gel filtration chromatography and high-performance liquid chromatography. The molecular mass and amino acids sequences of the purified peptides were determined using a Quadrupole time-of-flight mass spectrometer (Q-TOF MS). One of the antioxidative peptides, Trp–Tyr–Ser–Leu, displayed the highest DPPH radical scavenging activity (IC50=273·63 μm) and superoxide radical scavenging activity (IC50=558·42 μm). These results suggest that hydrolysates from whey proteins are good potential source of natural antioxidants.

The overall objective of this study was to evaluate agreement between rectal (RT) and vaginal temperature (VT) measured with the same temperature loggers in dairy cows. Three experiments were conducted. The study began with a validation in vitro of 24 temperature loggers comparing them to a calibrated liquid-in-glass thermometer as a reference method. The association and agreement between the 24 temperature loggers with the reference method was r=0·996 (P<0·001) with a negligible coefficient of variance (0·005) between the loggers. In-vivo temperature loggers were tested in 11 healthy post-partum cows (Experiment 2) and 12 early post-partum cows with greater body temperature (Experiment 3). Temperature loggers were set to record VT and RT at 1-min intervals. To prevent rectal and vaginal straining and potential expulsion of temperature logger an epidural injection of 2·5 ml of 2% Procain was administered. Association between RT and VT was r=0·92 (P<0·001; Experiment 2) and r=0·94 (P<0·001; Experiment 3) with a negligible difference of −0·1 and 0·01 °C. Bland-Altman plots demonstrated agreement between RT and VT for healthy and early post-partum cows with greater body temperature in Experiments 2 and 3, respectively. Furthermore the intra-class correlation coefficient between RT and VT measured with identical loggers within cows of Experiments 2 and 3 also demonstrated greater agreements (P<0·001). Therefore, continuous VT monitoring with temperature loggers can be used as a measure of body temperature in dairy cows.

The robustness of in-line raw milk analysis with near-infrared spectroscopy (NIRS) was tested with respect to the prediction of the raw milk contents fat, protein and lactose. Near-infrared (NIR) spectra of raw milk (n = 3119) were acquired on three different farms during the milking process of 354 milkings over a period of six months. Calibration models were calculated for: a random data set of each farm (fully random internal calibration); first two thirds of the visits per farm (internal calibration); whole datasets of two of the three farms (external calibration), and combinations of external and internal datasets. Validation was done either on the remaining data set per farm (internal validation) or on data of the remaining farms (external validation). Excellent calibration results were obtained when fully randomised internal calibration sets were used for milk analysis. In this case, RPD values of around ten, five and three for the prediction of fat, protein and lactose content, respectively, were achieved. Farm internal calibrations achieved much poorer prediction results especially for the prediction of protein and lactose with RPD values of around two and one respectively. The prediction accuracy improved when validation was done on spectra of an external farm, mainly due to the higher sample variation in external calibration sets in terms of feeding diets and individual cow effects. The results showed that further improvements were achieved when additional farm information was added to the calibration set. One of the main requirements towards a robust calibration model is the ability to predict milk constituents in unknown future milk samples. The robustness and quality of prediction increases with increasing variation of, e.g., feeding and cow individual milk composition in the calibration model.

Ovarian steroids, oestradiol and progesterone, are required for normal mammary growth at puberty and during pregnancy. They contribute to mammary parenchyma development by stimulating mammary epithelial cell (MEC) proliferation. However several studies demonstrate that oestradiol negatively affects milk production during the declining phase of lactation, but the oestradiol effect on MEC in lactating mammary gland remains unclear. The objective of this study was to investigate the differential effect of oestradiol on bovine MECs mimicking two physiological statuses: active and early apoptotic MECs. We demonstrated that oestradiol has a major effect on early apoptotic MECs and might accelerate MEC apoptosis by activation of caspases rather than by inducing apoptosis in active MECs. Early apoptotic MECs could be compared with senescent cells in the late-lactation mammary gland. These results suggest that the negative effect of oestradiol on milk production during the declining phase of lactation would be due to an enhancement of apoptotic processes in MECs.

Galacto-oligosaccharides (GOS) are prebiotics that have a beneficial effect on human health by promoting the growth of probiotic bacteria in the gut. GOS are commonly produced from lactose in an enzymatic reaction catalysed by β-galactosidase, named transglycosylation. Lactose is the main constituent of whey permeate (WP), normally wasted output from the cheese industry. Therefore, the main goal of this work was to optimise the synthesis of GOS in WP using β-galatosidase from Aspergillus oryzaea. WP and whey permeate enzymatically treated (WP-GOS) were used as culture media of Lactobacillus plantarum 299v. Lb. plantarum 299v attained the stationary phase in approximately 16 h, reaching 3·6 and 4·1×108 CFU/ml in WP and WP-GOS, respectively. The in situ synthesised GOS were not consumed during growth. No significant differences were observed in the growth kinetics of microorganisms in both media. After fermentation, microorganisms were dehydrated by freeze-drying and spray-drying and stored. The recovery of microorganisms after fermentation, dehydration and storage at 4 °C for at least 120 d was above 108 CFU/g. These studies demonstrated that WP is an appropriate substrate for the synthesis of GOS and the obtained product is also adequate as culture medium of Lb. plantarum 299v. The coexistence of GOS and dehydrated viable probiotic microorganisms, prepared using an effluent as raw material, represents the main achievement of this work, with potential impact in the development of functional foods.

Calcium-fortified foods, especially milk and dairy products are recommended to be consumed daily for groups in risk of nutritional deficiency, including children, young adults, menopausal women, pregnant women and the elderly, however Ca-supplementation promotes gallstone formation because Ca is a nucleating factor. The objective of the current study was to assess the influence of cow or goat milk-based diets, either normal or Ca-supplemented, on bile composition, biochemical parameters and hepatic antioxidant status. Weanling male rats were randomly divided into six groups, fed standard, goat or cow milk-based diets, either with normal Ca content (5·0 g/kg), or Ca-supplemented (10·0 g/kg), for 2 weeks. Bile cholesterol concentration and output was higher in rats fed goat milk in comparison with those fed with standard and cow-milk-based diet. Ca-supplementation increased lithogenic index with the standard and cow-milk based diets, this change was not observed with the goat milk diet. Activities of plasma transaminases were also lower in the animals fed Ca-supplemented goat milk, in comparison with the other diets assayed. In general, Ca-supplement in the diet led to an increase in the hepatic oxidative damage, with an increase in the activities of all the antioxidant enzymes studied in the standard and cow milk diet, but not with goat milk. The habitual consumption of goat milk has positive effects on the plasma lipid profile, biliary composition and hepatic antioxidant defence. In addition, under our experimental conditions, Ca-supplementation of this type of milk does not increase the lithogenic index, or hepatic oxidative damage.

The aim of the study was to identify the species of Enterobacteriaceae present in Montasio cheese and to assess their potential to produce biogenic amines. Plate count methods and an Enterobacterial Repetitive Intergenic Consensus Polymerase Chain Reaction (ERIC-PCR) approach, combined with 16S rDNA sequencing, were used to investigate the Enterobacteriaceae community present during the cheesemaking and ripening of 6 batches of Montasio cheese. Additionally, the potential decarboxylation abilities of selected bacterial isolates were qualitatively and quantitatively assessed against tyrosine, histidine, ornithine and lysine. The most predominant species detected during cheese manufacturing and ripening were Enterobacter cloacae, Escherichia coli and Hafnia alvei. The non-limiting physico-chemical conditions (pH, NaCl% and aw) during ripening were probably the cause of the presence of detectable levels of Enterobacteriaceae up to 120 d of ripening. The HPLC test showed that cadaverine and putrescine were the amines produced in higher amounts by almost all isolates, indicating that the presence of these amines in cheese can be linked to the presence of high counts of Enterobacteriaceae. 44 isolates produced low amounts of histamine (<300 ppm), and four isolates produced more than 1000 ppm of this amine. Only 9 isolates, belonging to the species Citrobacter freundii, Esch. coli and Raoultella ornithinolytica, appeared to produce tyramine. These data provided new information regarding the decarboxylase activity of some Enterobacteriaceae species, including Pantoea agglomerans, Esch. fergusonii and R. ornithinolytica.