Antioxidative factors in milk

Short communication: Phenotypic characterization of total antioxidant activity of buffalo, goat, and sheep milk

Free radicals are reactive and unstable waste molecules produced by cells, responsible of damages and alteration on DNA, proteins, and fat. The daily intake of antioxidant compounds, acting against free radicals and their detrimental effects, is essential for human health. Milk contains several compounds with antioxidant activity, and the sum of their reducing potential blocking free radicals development is defined as total antioxidant activity (TAA). This novel trait has been described in literature both in individual and bulk cow milk, but there are no reports from other dairy species. Therefore, the present study aimed to investigate phenotypic variation of TAA in individual samples of buffalo (n = 105), goat (n = 112), and sheep (n = 198) milk. Total antioxidant activity was measured through a reference spectrophotometric method, and expressed as millimoles per liter of Trolox equivalents (TE). The greatest TAA was observed in sheep milk, averaging 7.78 mmol/L of TE and showing also the broadest phenotypic variation expressed as coefficient of variation (13.98%). Significantly lower TAA values were observed for buffalo (7.35 mmol/L of TE) and goat (6.80 mmol/L of TE) milk, with coefficients of variation of 8.18 and 8.47%, respectively. Total antioxidant activity exhibited weak correlations with milk yield and chemical composition. Phenotypic values of TAA presented in this study will be used to assess the ability of mid-infrared spectroscopy to predict this new trait and thus to collect data at the population level.

Comparison of antioxidant capacity of cow and ewe milk kefirs

This research aimed to evaluate the effects of using either grain or commercial starter culture on the antioxidative capacity of cow and ewe milk kefirs. The antioxidant capacity of kefir samples during fermentation and 21 d of storage was assessed by using 3 assays: 2,2'-azino-bis(3-ethylbenzthiazoline-6-sulfonic acid) (ABTS) radical cation decolorization; 2,2-diphenyl-1-picrylhydrazyl (DPPH^•) radical scavenging activity assay; and Fe⁺³-reducing power (ferric reducing antioxidant power assay, FRAP). Vitamin E and β-carotene contents were also quantified. All kefir samples exhibited varying values for DPPH, ABTS, and FRAP assays depending on the starter culture and milk type. Vitamin E and β-carotene contents were similar in all kefir samples during storage. The results of this study suggest that milk type (cow or ewe) and culture type (kefir grains or commercial starter) were the significant parameters for the antioxidative activity of kefir.

Addition of milk to tea infusions: Helpful or harmful? Evidence from in vitro and in vivo studies on antioxidant properties

Tea consumption is practised as a tradition, and has shown potential to improve human health. Maximal uptake of tea antioxidants and milk proteins without a negative impact on tea flavor is highly desired by consumers. There is a conflicting evidence of the effect of milk addition to tea on antioxidant activity. Differences in the type of tea, the composition, type and amount of milk, preparation method of tea-milk infusions, the assays used to measure antioxidant activity, and sampling size likely account for different findings. Interactions between tea polyphenols and milk proteins, especially between catechins and caseins, could account for a decrease in antioxidant activity, although other mechanisms are also possible, given the similar effects between soy and bovine milk. The role of milk fat globules and the milk fat globule membrane surface is also important when considering interactions and loss of polyphenolic antioxidant activity, which has not been addressed in the literature.

In vitro and in vivo antioxidant potential of milks, yoghurts, fermented milks and cheeses: a narrative review of evidence

The antioxidant potential (AP) is an important nutritional property of foods, as increased oxidative stress is involved in most diet-related chronic diseases. In dairy products, the protein fraction contains antioxidant activity, especially casein. Other antioxidants include: antioxidant enzymes; lactoferrin; conjugated linoleic acid; coenzyme Q10; vitamins C, E, A and D3; equol; uric acid; carotenoids; and mineral activators of antioxidant enzymes. The AP of dairy products has been extensively studied in vitro, with few studies in animals and human subjects. Available in vivo studies greatly differ in their design and objectives. Overall, on a 100 g fresh weight-basis, AP of dairy products is close to that of grain-based foods and vegetable or fruit juices. Among dairy products, cheeses present the highest AP due to their higher protein content. AP of milk increases during digestion by up to 2·5 times because of released antioxidant peptides. AP of casein is linked to specific amino acids, whereas β-lactoglobulin thiol groups play a major role in the AP of whey. Thermal treatments such as ultra-high temperature processing have no clear effect on the AP of milk. Raw fat-rich milks have higher AP than less fat-rich milk, because of lipophilic antioxidants. Probiotic yoghurts and fermented milks have higher AP than conventional yoghurt and milk because proteolysis by probiotics releases antioxidant peptides. Among the probiotics, Lactobacillus casei/acidophilus leads to the highest AP. The data are insufficient for cheese, but fermentation-based changes appear to make a positive impact on AP. In conclusion, AP might participate in the reported dairy product-protective effects against some chronic diseases.

Oxidative changes in lipids, proteins, and antioxidants in yogurt during the shelf life

Oxidation processes in milk and yogurt during the shelf life can result in an alteration of protein and lipid constituents. Therefore, the antioxidant properties of yogurt in standard conditions of preservation were evaluated. Total phenols, free radical scavenger activity, degree of lipid peroxidation, and protein oxidation were determined in plain and skim yogurts with or without fruit puree. After production, plain, skim, plain berries, and skim berries yogurts were compared during the shelf life up to 9 weeks. All types of yogurts revealed a basal antioxidant activity that was higher when a fruit puree was present but gradually decreased during the shelf life. However, after 5–8 weeks, antioxidant activity increased again. Both in plain and berries yogurts lipid peroxidation increased until the seventh week of shelf life and after decreased, whereas protein oxidation of all yogurts was similar either in the absence or presence of berries and increased during shelf life. During the shelf life, a different behavior between lipid and protein oxidation takes place and the presence of berries determines a protection only against lipid peroxidation.

Therapeutic potential of dairy bioactive peptides: A contemporary perspective

Dairy products are associated with numerous health benefits. These are a good source of nutrients such as carbohydrates, protein (bioactive peptides), lipids, minerals, and vitamins, which are essential for growth, development, and maintenance of the human body. Accordingly, dairy bioactive peptides are one of the targeted compounds present in different dairy products. Dairy bioactive compounds can be classified as antihypertensive, anti-oxidative, immmunomodulant, anti-mutagenic, antimicrobial, opoid, anti-thrombotic, anti-obesity, and mineral-binding agents, depending upon biological functions. These bioactive peptides can easily be produced by enzymatic hydrolysis, and during fermentation and gastrointestinal digestion. For this reason, fermented dairy products, such as yogurt, cheese, and sour milk, are gaining popularity worldwide, and are considered excellent source of dairy peptides. Furthermore, fermented and non-fermented dairy products are associated with lower risks of hypertension, coagulopathy, stroke, and cancer insurgences. The current review article is an attempt to disseminate general information about dairy peptides and their health claims to scientists, allied stakeholders, and, certainly, readers.

Investigation on the pitting of potato starch granules during high frequency ultrasound treatment

In this paper, the pitting of potato starch granules in aqueous suspensions (1%) by high-frequency high-power ultrasound (850kHz at a power of 0.2W, 2W or 3.7W; and also 500kHz and 1MHz at a power of 2W) is reported. The number of pits per starch granules was found to be independent of the amylose content of starches, and the surface properties of starch granules as modified through SDS and ethanol washing. At 850kHz, the maximum number of pits per starch granule, for both normal and waxy starches, did not exceed 11. However, a close inspection of fractionated starch granules based on their sizes showed that there is an optimum granule size for which a maximum pit number is obtained. For example, starch granules with diameter size range of ∼15 to ∼30μm had a maximum pit number (between 10 and 20 pits per granule) when sonicated (2W, 850kHz and 30min); while sonication of small (<10μm) and very large (>45μm) granules resulted in a smaller number of pits per granule (∼5). Further, the maximum number of pits per granules is also found to be proportional to the ultrasound frequency, with values of approximately 7, 10 and 11 at 0.50, 0.85, and 1MHz, respectively. FTIR measurements did not show any breakup of starch molecules.

Camel milk ameliorates hyperglycaemia and oxidative damage in type-1 diabetic experimental rats

This study was designed to assess anti-diabetic potential of goat, camel, cow and buffalo milk in streptozotocin (STZ) induced type 1 diabetic albino wistar rats. A total of 48 rats were taken for the study where one group was kept as non-diabetic control group (8 rats) while others (40 rats) were made diabetic by STZ (50 mg/kg of body weight) injection. Among diabetic rats, a control group (8 rats) was kept and referred as diabetic control whereas other four groups (8 rats each) of diabetic rats were fed on 50 ml of goat or camel or cow or buffalo milk for 4 weeks. All the rats (non-diabetic and diabetic) were maintained on standard diet for four weeks. STZ administration resulted in enhancement of glucose, total cholesterol, triglyceride, low density lipoprotein, HbA1c and reduction in high density lipoprotein in plasma and lowering of antioxidative enzymes (catalase, glutathione peroxidase and superoxide dismutase) activities in pancreas, kidney, liver and RBCs, coupled with enhanced levels of TBARS and protein carbonyls in pancreas, kidney, liver and plasma. OGTT carried out at the end of 4 week milk feeding indicated that all milks helped in early maintenance of glucose level. All milks reduced atherogenic index. In camel milk fed diabetic group, insulin concentration enhanced to level noted for non-diabetic control while goat, cow and buffalo milk failed to restore insulin level. HbA1c level was also restored only in camel milk fed diabetic group. The level of antioxidative enzymes (catalase, GPx and SOD) in pancreas enhanced in all milk fed groups. Camel milk and to a reasonable extent goat milk reduced formation of TBARS and PCs in tissues and blood. It can be concluded that camel milk ameliorates hyperglycaemia and oxidative damage in type-1 diabetic experimental rats. Further, only camel milk completely ameliorated oxidative damage in pancreas and normalised insulin level.

Use of Onion Extract as a Dairy Cattle Feed Supplement: Monitoring Propyl Propane Thiosulfonate as a Marker of Its Effect on Milk Attributes

Onion extract is used as a feed supplement for the diet of dairy cows, acting as inhibitor of methane production; however, its properties could alter sensory attributes of milk. In this work, we propose a method to evaluate the influence of this extract on milk properties, using propyl propane thiosulfonate (PTSO) as a marker. PTSO is extracted using a quick, easy, cheap, effective, rugged, and safe procedure and monitored by high-performance liquid chromatography with ultraviolet detection. The method was applied to milk samples obtained from 100 dairy cows fed during 2 months with enriched feed. In addition, a milk tasting panel was established to evaluate the PTSO residue that should not be exceeded to guarantee milk sensory attributes. It was established that a value of PTSO lower than 2 mg kg^-1 does not alter milk organoleptic properties. This fact makes onion extract an interesting alternative as a feed supplement to control the methane emissions without any influence on milk attributes.

The protective effect of Buffalo's milk against toluene induced-nephrotoxicity in rats

Background:

Toluene is widely used in different activities of industrial, commercial and household applications. It can cause damage to the human body. Buffalos’ milk has a good nutritive value.

Objectives:

The aim of this study is to examine the negative effects of toluene on kidney tissues and to investigate the protective effects of buffalo’s milk against toluene-induced nephrotoxicity in rats.

Materials and Methods:

Forty adult male Wistar rats (180-220 g weight) were randomly assigned to eight groups (n = 5). Animals in groups I to IV received oral gavage 1 mL distilled water (DH₂O) and groups V to VIII received oral gavage 1 mL buffalo’s milk. Ten minutes later, animals were received toluene (i.p) at doses of 300 mg/kg (groups I and V), 600 mg/kg (groups of II and VI), and 900 mg/kg (groups of III and VII), respectively. The animals in groups IV (control) and VIII were injected vehicle (corn oil) only. The experiment repeated for seven consecutive days. Twenty-four hours after the last administration, animals were killed with overdose of sodium pentobarbital. Blood samples were analyzed for blood urea nitrogen (BUN) and creatinine (Cr). One part of the kidney tissues were excised for measuring the activities of superoxide dismutase (SOD), glutathione reductase (GR) and catalase (CAT) and the level of malondialdehyde (MDA). Another parts were excised for histopatholgical examination.

Results:

Administration of toluene to male rats produced dose-dependent damage in the kidney. This was noted by elevation of BUN, Cr and MDA levels. In contrast, diminished the CAT, GR and SOD enzyme activities in rats treated with toluene when compared to those in control animals. Histopathological manifestations were also observed in dose related manner in toluene-treated rats. Buffalo’s milk had no effect on the biochemical parameters and kidney morphology when compared to those in control. However, it was able to prevent rat kidney against toluene toxicity.

Conclusions:

The results of this study demonstrated that toluene damages kidney tissue and is a nephrotoxic substance. Buffalo’s milk was able to prevent the renal damage as an antioxidant and a nephroprotective agent.

Melatonin Concentrations and Antioxidative Capacity of Human Breast Milk According to Gestational Age and the Time of Day

BACKGROUND

While changes in the composition of breast milk throughout the lactation period are well known, little is known about the antioxidative capacity of breast milk and its regulation as a function of time of day.

OBJECTIVE

The aim of this study was to evaluate the antioxidative capacity in breast milk and its regulation by time of day.

METHODS

Melatonin, superoxide dismutase (SOD), glutathione peroxidase 3 (Gpx3) concentrations, and the total antioxidative capacity (TAOC) were analyzed in 105 breast milk samples and 12 maternal serum samples from 21 healthy nursing mothers.

RESULTS

Comparison between daytime breast milk (collected from 1000-2200 h) and nighttime breast milk (collected from 2200-1000 h) revealed significantly higher concentrations of melatonin and Gpx3 in nighttime milk (melatonin: 1.5 pg/mL [1.0-2.1] day vs 7.3 pg/mL [3.8-13.6] night, median [quartiles], with an estimated mean night-to-day ratio of 5.2 [3.9, 7.1], P < .001; Gpx3: 1436 ng/mL [765-2060] day vs 1800 ng/mL [1242-2297] night, night-to-day difference 192.1 [0.6, 383.7], P = .049). Subgroup analysis showed that melatonin had a circadian rhythm in both preterm and term milk, with a significantly higher nighttime concentration ( P < .001), while antioxidant enzymes had a circadian rhythm only in preterm milk, with a significantly higher nighttime concentration for Gpx3 and a significant higher daytime concentration for SOD and TAOC ( P = .041 and P = .049, respectively). We found no significant correlation between the concentration of melatonin and the concentration of SOD, Gpx3, or TAOC. Moreover, there were no significant correlations observed between gestational age and the concentration of melatonin and antioxidant enzymes.

CONCLUSION

Because of its higher melatonin and Gpx3 content, future research is needed to determine if preterm nighttime milk ought to be the first choice in the feeding of high-risk preterm infants.

Systematic review and meta-analysis of human milk intake and retinopathy of prematurity: a significant update

OBJECTIVE

Two recent meta-analyses have studied the association of exclusive or mainly human milk intake (HMI) on retinopathy of prematurity (ROP). One of these meta-analysis found a protective effect of only or mainly HMI on Severe ROP but not on any stage ROP. However, both these meta-analyses did not find protection from any stage ROP or Severe ROP with any amount of HMI. The objective of this study was to study the association between any amount of HMI and the development of All ROP and Severe ROP in very-low birth weight infants (VLBWI) and extremely low birth weight infants (ELBWI) by systematic review using PRISMA-P guidelines and meta-analysis.

STUDY DESIGN

Exposure, controls and outcomes studied were any amount of HMI vs no HMI and All ROP/Severe ROP in VLBWI/ELBWI. All ROP was defined as all stages of ROP pooled together, and Severe ROP as ⩾stage 3 ROP and ROP requiring intervention. Results and effect sizes are expressed as odds ratio (OR), relative risk (RR), risk difference (RD) and number needed to treat (NNT) with 95% confidence intervals (95% CI). Data sources used were PubMed, MEDLINE, EMBASE, Cochrane Central Register of Clinical Trials, Scopus and CINAHL until 24 April 2015. Extracted data were pooled using a fixed effects model. Heterogeneity was assessed. Sensitivity analysis was performed.

RESULTS

Five hundred nine of 1701 infants who received any amount of HMI developed All ROP vs 310 of 760 infants without HMI developed All ROP with a pooled OR 0.63* (0.51,0.78), RR 0.76* (0.67,0.86) and RD -0.09* (-0.13,-0.05). The NNT with any amount of HMI was 11* (8,20) (*P<0.0001) to prevent one case of All ROP. 204 of 2465 infants who received any amount of HMI developed Severe ROP vs 85 of 764 infants without HMI developed Severe ROP with a pooled OR 0.74* (0.56,0.98), RR 0.77* (0.60,0.98) and RD -0.03* (-0.05,-0.00). The NNT with any amount of HMI was 33* (*P=0.04) to prevent one case of Severe ROP.

CONCLUSION

Any amount of HMI is strongly associated with the protection from All ROP and Severe ROP.

Anti-stress activity of Sargassum polycystum extracts using a cold restraint stress model

Anti-stress effects of polyphenol extracts of Sargassum polycystum were evaluated. Polyphenol extracts of S. polycystum and diazepam were compared for anti-stress activities using a cold restraint animal stress model. S. polycystum extracts were administered orally at dosages of 150 and 450 mg/kg. Diazepam, an anti-stress agent, was used as a standard drug at 0.18 mg/kg p.o. Both dosages of S. polycystum extracts showed good anti-stress effects. Due to cold restraint stress there was an imbalance in levels of biochemical parameters, including glucose, triglycerides, cholesterol, alkaline phosphatase (ALP), alanine aminotransferase (ALT), and aspartate amino transferase (AST), which were near normalized following adminstration of S. polycystum extracts. Polyphenol extracts of S. polycystum at oral dosages of 150 and 450 mg/kg exerted anti-stress effects.

Molecular nutrition: Interaction of nutrients, gene regulations and performances

Nutrition deals with ingestion of foods, digestion, absorption, transport of nutrients, intermediary metabolism, underlying anabolism and catabolism, and excretion of unabsorbed nutrients and metabolites. In addition, nutrition interacts with gene expressions, which are involved in the regulation of animal performances. Our laboratory is concerned with the improvement of animal productions, such as milks, meats and eggs, with molecular nutritional aspects. The present review shows overviews on the nutritional regulation of metabolism, physiological functions and gene expressions to improve animal production in chickens and dairy cows.

Antioxidant capacity of different cheeses: Affecting factors and prediction by near infrared spectroscopy

In this study, we analyzed antioxidant capacity of 224 cheese samples prepared using 16 varied mixtures of milk from cows, ewes, and goats, in 2 manufacturing seasons (winter and summer), and over 6mo of ripening. Antioxidant capacity was evaluated using the spectrophotometric 2,2-azinobis(3-ethylenebenzothiazoline-6-sulfonic acid) (ABTS) method. Total antioxidant capacity was significantly correlated with season of manufacturing and time of ripening but not with animal species providing the milk. Moreover, statistically significant correlations between the total antioxidant capacity and retinol (r=0.399), fat percentage (r=0.308), protein percentage (r=0.366), K (r=0.385), Mg (r=0.312), Na (r=0.432), and P (0.272) were observed. We evaluated the use of near infrared spectroscopy technology, together with the use of a remote reflectance fiber-optic probe, to predict the antioxidant capacity of cheese samples. The model generated allowed us to predict antioxidant capacity in unknown cheeses of different compositions and ripening times.

Cavitation and non-cavitation regime for large-scale ultrasonic standing wave particle separation systems--In situ gentle cavitation threshold determination and free radical related oxidation

We here suggest a novel and straightforward approach for liter-scale ultrasound particle manipulation standing wave systems to guide system design in terms of frequency and acoustic power for operating in either cavitation or non-cavitation regimes for ultrasound standing wave systems, using the sonochemiluminescent chemical luminol. We show that this method offers a simple way of in situ determination of the cavitation threshold for selected separation vessel geometry. Since the pressure field is system specific the cavitation threshold is system specific (for the threshold parameter range). In this study we discuss cavitation effects and also measure one implication of cavitation for the application of milk fat separation, the degree of milk fat lipid oxidation by headspace volatile measurements. For the evaluated vessel, 2 MHz as opposed to 1 MHz operation enabled operation in non-cavitation or low cavitation conditions as measured by the luminol intensity threshold method. In all cases the lipid oxidation derived volatiles were below the human sensory detection level. Ultrasound treatment did not significantly influence the oxidative changes in milk for either 1 MHz (dose of 46 kJ/L and 464 kJ/L) or 2 MHz (dose of 37 kJ/L and 373 kJ/L) operation.

Milk derived bioactive peptides and their impact on human health - A review

Milk-derived bioactive peptides have been identified as potential ingredients of health-promoting functional foods. These bioactive peptides are targeted at diet-related chronic diseases especially the non-communicable diseases viz., obesity, cardiovascular diseases and diabetes. Peptides derived from the milk of cow, goat, sheep, buffalo and camel exert multifunctional properties, including anti-microbial, immune modulatory, anti-oxidant, inhibitory effect on enzymes, anti-thrombotic, and antagonistic activities against various toxic agents. Majority of those regulate immunological, gastrointestinal, hormonal and neurological responses, thereby playing a vital role in the prevention of cancer, osteoporosis, hypertension and other disorders as discussed in this review. For the commercial production of such novel bioactive peptides large scale technologies based on membrane separation and ion exchange chromatography methods have been developed. Separation and identification of those peptides and their pharmacodynamic parameters are necessary to transfer their potent functional properties into food applications. The present review summarizes the preliminary classes of bioactive milk-derived peptides along with their physiological functions, general characteristics and potential applications in health-care.

Combined Effect of Pressure-Assisted Thermal Processing and Antioxidants on the Retention of Conjugated Linoleic Acid in Milk

The effect of pressure-assisted thermal processing (PATP) in combination with seven synthetic antioxidants was evaluated on the retention of conjugated linoleic acid (CLA) in enriched milk. Milk rich in CLA was first saturated with oxygen, followed by the addition of either catechin, cysteine, ascorbic acid, tannic acid, gallic acid, caffeic acid or p-coumaric acid (500 mg kg⁻¹ untreated milk). Samples were treated at 600 MPa and 120 °C up to 15 min of holding time. During PATP, CLA not only oxidized at a slower rate, but also less oxygen was consumed compared to the control (0.1 MPa and 120 °C). In addition, phenolic antioxidants were able to quench dissolved oxygen in samples treated with PATP. For those samples added with gallic acid and catechin, 85% and 75% of the CLA was retained after 15 min of holding time at 600 MPa and 120 °C, respectively. The retention of CLA was enhanced by the application of PATP in combination with gallic acid.

Bioavailability of the flavonol quercetin in neonatal calves after oral administration of quercetin aglycone or rutin

Polyphenols, such as flavonoids, are secondary plant metabolites with potentially health-promoting properties. In newborn calves flavonoids may improve health status, but little is known about the systemically availability of flavonoids in calves to exert biological effects. The aim of this study was to investigate the oral bioavailability of the flavonol quercetin, applied either as quercetin aglycone (QA) or as its glucorhamnoside rutin (RU), in newborn dairy calves. Twenty-one male newborn German Holstein calves were fed equal amounts of colostrum and milk replacer according to body weight. On d 2 and 29 of life, 9 mg of quercetin equivalents/kg of body weight, either fed as QA or as RU, or no quercetin (control group) were fed together with the morning meal. Blood samples were taken before and 0.5, 1, 1.5, 2, 2.5, 3, 4, 5, 6, 12, 24, and 48 h after feed intake. Quercetin and quercetin metabolites with an intact flavonol structure (isorhamnetin, tamarixetin, and kaempferol) were analyzed in blood plasma after treatment with glucuronidase or sulfatase by HPLC with fluorescence detection. Maximum individual plasma concentration was depicted from the concentration-time-curve on d 2 and 29, respectively. Additional blood samples were taken to measure basal plasma concentrations of total protein, albumin, urea, and lactate as well as pre- and postprandial plasma concentrations of glucose, nonesterified fatty acids, insulin, and cortisol. Plasma concentrations of quercetin and its metabolites were significantly higher on d 2 than on d 29 of life, and administration of QA resulted in higher plasma concentrations of quercetin and its metabolites than RU. The relative bioavailability of total flavonols (sum of quercetin and its metabolites isorhamnetin, tamarixetin, and kaempferol) from RU was 72.5% on d 2 and 49.6% on d 29 when compared with QA (100%). Calves fed QA reached maximum plasma concentrations of total flavonols much earlier than did RU-fed calves. Plasma metabolites and hormones were barely affected by QA and RU feeding in this experiment. Taken together, orally administrated QA resulted in a greater bioavailability of quercetin than RU on d 2 and 29, respectively, and quercetin bioavailability of quercetin and its metabolites differed markedly between calves aged 2 and 29 d.

Contribution of n-3 long-chain polyunsaturated fatty acids to human milk is still low in Hungarian mothers

Maternal diet has decisive influence on the fatty acid composition of human milk. Fifteen years ago, we found outstandingly low contribution of docosahexaenoic acid (DHA) to human milk in a small group of Hungarian mothers. The major aim of the present study was to investigate whether DHA status in human milk in Hungary changed during the last 15 years. We aimed to examine the fatty acid composition of human milk at three different stages of lactation (3rd day, 6th week, and 6th month) in healthy Hungarian mothers. Fatty acid composition of human milk lipids was determined by gas chromatograph with flame ionization detector. Contribution of arachidonic acid to the fatty acid composition of human milk significantly decreased during lactation (0.91 [0.38] in colostrum, 0.53 [0.17] at 6th week, and 0.46 [0.13] at 6th month, p < 0.01). The contribution of DHA significantly decreased from colostrum to the 6th week of lactation (0.29 [0.12] and 0.14 [0.04], p < 0.01), without further changes by 6 months (0.12 [0.10]).

CONCLUSION

The contribution of DHA to the fatty acid composition of mature human milk in Hungarian mothers is still among the lowest values ever reported in the literature.

Dietary arachidonic acid in perinatal nutrition: a commentary

Arachidonic acid (AA) is supplied together with docosahexaenoic acid (DHA) in infant formulas, but we have limited knowledge about the effects of supplementation with either of these long-chain polyunsaturated fatty acids (LCPUFA) on growth and developmental outcomes. AA is present in similar levels in breast milk throughout the world, whereas the level of DHA is highly diet dependent. Autopsy studies show similar diet-dependent variation in brain DHA, whereas AA is little affected by intake. Early intake of DHA has been shown to affect visual development, but the effect of LCPUFA on neurodevelopment remains to be established. Few studies have found any functional difference between infants supplemented with DHA alone compared to DHA+AA, but some studies show neurodevelopmental advantages in breast-fed infants of mothers supplemented with n-3 LCPUFA alone. It also remains to be established whether the AA/DHA balance could affect allergic and inflammatory outcomes later in life. Disentangling effects of genetic variability and dietary intake on AA and DHA-status and on functional outcomes may be an important step in the process of determining whether AA-intake is of any physiological or clinical importance. However, based on the current evidence we hypothesize that dietary AA plays a minor role on growth and development relative to the impact of dietary DHA.

Phenolic content and ferric reducing-antioxidant power of cow's milk produced in different pasture-based production systems in southern Brazil

BACKGROUND

Phenolic compounds are widely present in forage. However, few studies have been carried out to investigate the presence of these compounds in animal products such as milk. In this study, the total phenolic content (TPC) and ferric reducing-antioxidant power (FRAP) of milk produced under agroecological and conventional management systems in southern Brazil were determined. Three systems were compared: (a) agroecological, with intensive rotational grazing, also known as Voisin grazing (ECO); (b) semi-intensive conventional (SIC); and (c) conventional grazing (CGR) (n = 8 per group). Pastures with distinct and more diverse botanical composition were observed on the ECO farms.

RESULTS

Significantly (P < 0.05) lower amounts of TPC were found in agroecologically produced milk in autumn and summer and the CGR system showed the highest FRAP value (P < 0.05) for the samples collected in autumn. Positive correlations where found between the TPC and FRAP values obtained for the milk samples (0.198, P < 0.05), milk FRAP and forage TPC values (0.344, P < 0.05), and the TPC and FRAP values obtained for the forage (0.70, p < 0.01). PCA applied to the UV spectra dataset (200-350 nm) clearly distinguished the samples collected from the ECO system in the winter.

CONCLUSION

Our results revealed that, under the conditions prevalent in southern Brazil, since the cows were allowed to graze in all of the systems, the TPC and antioxidant capacity of the milk samples showed minimal variation. However, since the forage TPC and FRAP values for the milk were correlated, TPC appears to be a promising variable for the purpose of monitoring forage prior to its selection aimed at enhancing the antioxidant activity of milk.

Inactivation of Enterobacter aerogenes in reconstituted skim milk by high- and low-frequency ultrasound

The inactivation of Enterobacter aerogenes in skim milk using low-frequency (20kHz) and high-frequency (850kHz) ultrasonication was investigated. It was found that low-frequency acoustic cavitation resulted in lethal damage to E. aerogenes. The bacteria were more sensitive to ultrasound in water than in reconstituted skim milk having different protein concentrations. However, high-frequency ultrasound was not able to inactivate E. aerogenes in milk even when powers as high as 50W for 60min were used. This study also showed that high-frequency ultrasonication had no influence on the viscosity and particle size of skim milk, whereas low-frequency ultrasonication resulted in the decrease in viscosity and particle size of milk. The decrease in particle size is believed to be due to the breakup of the fat globules, and possibly to the cleavage of the κ-casein present at the surface of the casein micelles. Whey proteins were also found to be slightly affected by low-frequency ultrasound, with the amounts of α-lactalbumin and β-lactoglobulin slightly decreasing.

Temperature effects on the ultrasonic separation of fat from natural whole milk

This study showed that temperature influences the rate of separation of fat from natural whole milk during application of ultrasonic standing waves. In this study, natural whole milk was sonicated at 600kHz (583W/L) or 1MHz (311W/L) with a starting bulk temperature of 5, 25, or 40°C. Comparisons on separation efficiency were performed with and without sonication. Sonication using 1MHz for 5min at 25°C was shown to be more effective for fat separation than the other conditions tested with and without ultrasound, resulting in a relative change from 3.5±0.06% (w/v) fat initially, of -52.3±2.3% (reduction to 1.6±0.07% (w/v) fat) in the skimmed milk layer and 184.8±33.2% (increase to 9.9±1.0% (w/v) fat) in the top layer, at an average skimming rate of ∼5g fat/min. A shift in the volume weighted mean diameter (D[4,3]) of the milk samples obtained from the top and bottom of between 8% and 10% relative to an initial sample D[4,3] value of 4.5±0.06μm was also achieved under these conditions. In general, faster fat separation was seen in natural milk when natural creaming occurred at room temperature and this separation trend was enhanced after the application of high frequency ultrasound.

Design parameters for the separation of fat from natural whole milk in an ultrasonic litre-scale vessel

The separation of milk fat from natural whole milk has been achieved by applying ultrasonic standing waves (1 MHz and/or 2 MHz) in a litre-scale (5L capacity) batch system. Various design parameters were tested such as power input level, process time, specific energy, transducer-reflector distance and the use of single and dual transducer set-ups. It was found that the efficacy of the treatment depended on the specific energy density input into the system. In this case, a plateau in fat concentration of ∼20% w/v was achieved in the creamed top layer after applying a minimum specific energy of 200 kJ/kg. In addition, the fat separation was enhanced by reducing the transducer reflector distance in the vessel, operating two transducers in a parallel set-up, or by increasing the duration of insonation, resulting in skimmed milk with a fat concentration as low as 1.7% (w/v) using raw milk after 20 min insonation. Dual mode operation with both transducers in parallel as close as 30 mm apart resulted in the fastest creaming and skimming in this study at ∼1.6 g fat/min.

Mode of delivery changes oxidative and antioxidative properties of human milk: a prospective controlled clinical investigation

OBJECTIVE

To evaluate the influence of delivery mode on oxidative stress in human breast milk.

METHODS

Thirty-three women who delivered by vaginal birth and 55 women who underwent cesarean section (CS) were included in this study. Colostral samples were collected on the second day after delivery. Total antioxidative status (TAS), total oxidative status (TOS), oxidative stress index (OSI), malonyldialdehyde (MDA), and glutathione peroxidase (GSH-Px) levels were determined and compared.

RESULTS

Colostrum TAS was significantly higher in women of vaginal birth, than in women with CS (p < 0.001). Milk TOS and OSI were found to be significantly increased in women with CS under general anesthesia. A marked increase in colostral GSH-Px levels after vaginal delivery was also noticed (p < 0.001).

CONCLUSION

This study revealed that vaginal birth is associated with decreased oxidative stress in colostrum than CS, which suggest that mode of delivery plays an important role in the antioxidative production of breast milk.

Nitrite and catalase levels rule oxidative stability and safety properties of milk: a review

This review focuses on recent evidence showing that various types of udder inflammation (mastitis) are associated with increased concentration of NO˙-derived metabolites, nitrite and nitrate, and oxidatively modified organic components under commercial farming and experimental conditions.

Effect of Sicilian pasture feeding management on content of α-tocopherol and β-carotene in cow milk

This study was performed to evaluate α-tocopherol and β-carotene contents of pasture milk under ordinary Sicilian farming conditions. Fourteen dairy farms were allocated into 2 balanced groups on the basis of cultivated (CULT) or spontaneous (SPO) pasture type feeding. Bulk milk per farm was collected 4 times from February through April at 3-wk intervals. Pasture botanical and diet composition, diet nutritional quality, milk yield and composition were estimated each time. Pasture intake levels were calculated based on feed analyses, hay and concentrate amounts fed, and milk yield and chemical composition. According to pasture intake, the farms were split into low pasture intake (LPI; <29.5% of dry matter) and high pasture intake (HPI; >29.5% of dry matter) groups. Milk samples per farm were analyzed for α-tocopherol and β-carotene contents by HPLC. The SPO group had higher levels of α-tocopherol and β-carotene in milk (0.7 and 0.3 mg/L, respectively) and milk fat (19.0 and 7.5 mg/kg fat, respectively) compared with the CULT group in milk (0.5 and 0.2 mg/L, respectively) and milk fat (14.6 and 4.9 mg/kg, respectively). High pasture intake compared with LPI increased α-tocopherol in milk fat (18.0 and 16.0 mg/kg of fat, respectively). However, only in the SPO (not in CULT), HPI compared with LPI increased milk α-tocopherol (0.8 vs. 0.6 mg/L, respectively), milk β-carotene (0.3 vs. 0.2 mg/L, respectively), and milk fat β-carotene (8.4 vs. 6.6 mg/kg, respectively). Results may be related to the different botanical composition of the respective pasture types and pasture intake. Spontaneous pasture compared with CULT contained a higher mass proportion of Asteraceae, Fabaceae, Cruciferae, Euphorbiaceae, and Malvaceae plants. Milk and milk fat α-tocopherol levels were higher on test-days (TD)-1, TD-2, and TD-4 compared with TD-3. For HPI farms, milk fat β-carotene content was higher on the first 2 TD compared with the last 2 TD. These differences could be related to plant biological stage. On Sicilian dairy farms, the highest milk α-tocopherol and β-carotene contents may be obtained feeding high levels of SPO pasture in the spring.