Antioxidative factors in milk

Effects of time and temperature of storage on chemical and nutritional characteristics of raw milk for Provolone Valpadana PDO cheesemaking: a multivariate approach

We evaluated the possibility of increasing the storage temperature of raw milk for Provolone Valpadana cheesemaking, to identify the most suitable conditions of time and temperature for a pre-maturation process. We used Principal Component Analysis (PCA) to analyze the overall effects of different storage conditions on chemical, nutritional and technological characteristics of the raw milk. Four different thermal storage cycles, two at fixed temperature/time (6 and 12°C for 60 h) and two with two-phase thermal cycle (10 and 12°C for 15 h, followed by refrigeration at 4°C for 45 h) were studied. Although a moderate heterogeneity among raw milks from the 11 producers of Provolone Valpadana cheese was observed, PCA revealed the critical aspects of the extreme storage conditions (60 h of refrigeration). Some samples resulted in anomalous behaviors, probably related to unexpected fermentation phenomena occurring with increasing storage temperature. The acidification and the increase in the contents of lactic acid, soluble calcium, and degree of retinol isomerization observed in the anomalous samples can compromise the technological functionality of milk. Conversely, the storage with a two-phase thermal cycle did not lead to variations in any measured characteristic, suggesting that mild refrigeration conditions (10 or 12°C for 15 h followed by 4°C for 45 h) could be a good compromise in favoring milk pre-maturation without altering its quality characteristics.

Decrease of activity of antioxidant enzymes, lysozyme content, and protein degradation in milk contaminated with heavy metals (cadmium and lead)

The aim of this study was to evaluate the effect of added Cd and Pb to milk on its stability by determining antioxidant enzymatic activities, lysozyme content, and protein degradation. Antioxidant enzymatic activities were spectrophotometrically determined by superoxide dismutase, catalase, xanthine oxidase, and glutathione peroxidase assays; lysozyme was identified and quantified by HPLC-UV analysis, and protein degradation was investigated by spectrophotometric analysis of advanced oxidation protein products (AOPP) and dityrosine content. In this study, contaminated milk samples showed a significant reduction in activity of all studied enzymes compared with control milk. The contamination of milk also led to a significant reduction in the lysozyme content; lysozyme content was decreased about 22% and 18% in Pb milk and Cd milk, respectively, compared with control milk. The presence of the contaminants in the milk resulted in a significant increase of both dityrosine concentration and AOPP compared with the control milk. Moreover, between types of contaminated milk, dityrosine and AOPP values were significantly higher in the Pb milk than in the Cd milk. Therefore, it is important to monitor the presence of these toxic elements in milk for the damage they cause to consumer health both directly due to their ingestion and indirectly due to loss of milk stability.

Whey Protein Hydrolysates of Sheep/Goat Origin Produced by the Action of Trypsin without pH Control: Degree of Hydrolysis, Antihypertensive Potential and Antioxidant Activities

Tryptic WPHs with considerable residual whey protein content intact were developed from two sheep/goat WPCs (65% and 80% protein) without pH control. Pasteurization was used to avoid denaturation. Changes in non-protein nitrogen (DH_TCASN), free amino groups (DH_TNBS), and major whey proteins were used to investigate the degree and extent of hydrolysis. Antihypertensive potential (ACE-IA), radical scavenging (DPPH-RSA), and iron chelation (Fe-CA) were assessed. No statistically significant changes in pH (5.84−6.29) were observed during hydrolysis and storage. At the start of hydrolysis, DH_TCASN was ≅11% for both substrates whereas DH_TNBS was >10% and >5% for WP65 and WP80, respectively. After one-hour hydrolysis, DH_TCASN was ≅17% for both substrates and DH_TNBS was ≅15% and ≅11% for WP65 and WP80, respectively. The β-lactoglobulin, α-lactalbumin, and caseinomacropeptide of WP65 were hydrolyzed by 14 ± 1.3%, 73.9 ± 2.6% and 37 ± 2.6%. The respective values for WP80 were 14.9 ± 1.7%, 79.9 ± 1%, and 32.7 ± 4.8%. ACE-IA of the hydrolysates of both substrates was much higher (>80%) than that of controls (<10%). Hydrolysis, substrate type, and storage did not affect the DPPH-RSA (45−54%). Fe-CA of the WP65 and WP80 hydrolysates were ≅40% and ≅20%, respectively; a similar outcome was found in the respective controls. Refrigerated storage for 17 h did not affect the degree of hydrolysis and biofunctional activities.

Reasonableness of Enriching Cow’s Milk with Vitamins and Minerals

Milk is an exceptional nutritional product that has been used for many millennia in human nutrition. Milk is a source of many valuable nutrients, including calcium, vitamin B, an especially significant amount of vitamin B2 and fat-soluble vitamins, such as A, D and E. Milk is an attractive product for fortification as it has a high nutritional density in a small volume and a relatively low price. Research shows positive health effects of drinking milk and consuming dairy products. Even more health benefits can be obtained from consuming fortified dairy products. A literature review, current nutritional recommendations, medical recommendations and an analysis of the market situation all recommend introducing milk enriched with minerals in combination with vitamins to the market. This concept corresponds to the current market demand and may supplement the missing and expected range of fortified milk and the correct number of recipients.

Effect of Purple Corn Anthocyanin on Antioxidant Activity, Volatile Compound and Sensory Property in Milk During Storage and Light Prevention

The aim of this study was to observe the effect of purple corn anthocyanin on the light-induced antioxidant activity, free radicals, volatile compounds, color parameters, and sensory properties of milk during storage. There were four groups: (1) negative control, no addition of anthocyanins + exposure to fluorescent light (NC); (2) positive control 1, no addition of anthocyanins + protected from fluorescent light (PC1); (3) positive control 2, the addition of 0.3% (w/v) anthocyanins + exposure to fluorescent light (PC2); and (4) the addition of 0.3% anthocyanins + protected from fluorescent light (AC). The results indicated that the concentration of antioxidant activity parameters in the NC group decreased during the entire storage period, whereas antioxidant activity parameters were unchanged except for the glutathione peroxidase (GSH-Px) in the AC group. Moreover, the NC group showed lower levels of 2,2-diphenyl-1-picrylhydrazyl (DPPH) scavenging activity and higher levels of superoxide anion and hydrogen peroxide than the other groups after 1 d of storage period. The extent of malondialdehyde accumulation and lipid peroxidation in the control groups were greater than that of the AC group. Twenty-two volatile compounds were determined in milk, which consisted of eight alcohols, three ketones, five aldehydes, two esters, and four hydrocarbons by headspace gas chromatography mass spectrometer analysis. Specifically, individual aldehydes, esters and hydrocarbons in the AC group remained at relatively stable values during storage relative to the other three groups. Stronger positive correlations were detected between several antioxidant activities (superoxide dismutase, GSH-Px) and DPPH scavenging activity as well as total ketones in milk. Adding of anthocyanin did not impact on the color values of L^*, a^* and b^* in light-protected milk during the entire storage period. Some sensory evaluation parameters (flat, garlic/onion/weedy, oxidized-light, oxidized-metal, rancid) in AC group were significantly higher than that of the control group at the end of the period. In conclusion, the current study revealed that the addition of purple corn anthocyanin pigment to light-protected milk had the potential to prevent lipid oxidation, enhance antioxidant activity, maintain volatile compounds and increase the sensory scores.

Electrochemical Methods for the Analysis of Milk

The milk and dairy industries are some of the most profitable sectors in many countries. This business requires close control of product quality and continuous testing to ensure the safety of the consumers. The potential risk of contaminants or degradation products and undesirable chemicals necessitates the use of fast, reliable detection tools to make immediate production decisions. This review covers studies on the application of electrochemical methods to milk (i.e., voltammetric and amperometric) to quantify different analytes, as reported over the last 10 to 15 years. The review covers a wide range of analytes, including allergens, antioxidants, organic compounds, nitrogen- and aldehyde containing compounds, biochemicals, heavy metals, hydrogen peroxide, nitrite, and endocrine disruptors. The review also examines pretreatment procedures applied to milk samples and the use of novel sensor materials. Final perspectives are provided on the future of cost-effective and easy-to-use electrochemical sensors and their advantages over conventional methods.

Bioaccessibility of terebinth (Pistacia terebinthus L.) coffee polyphenols: Influence of milk, sugar and sweetener addition

In this study, terebinth coffee formulations were prepared with whole or skimmed milk with or without sugar/sweetener in order to study the matrix effect on the bioaccessibility of terebinth polyphenols. Quercetin glycosides and catechin were the major flavonoids identified in the terebinth formulations, whereas gallic, protocatechuic, syringic and ellagic acids were determined as the non-flavonoid compounds. The in vitro gastrointestinal digestion model results revealed that addition of whole milk to terebinth coffee increased the total bioaccessible flavonoids significantly (45%) (p < 0.05), whereas skim milk addition did not result in any significant change. Furthermore, antioxidant capacity results measured with CUPRAC assay showed that addition of milk alone or together with sugar/sweetener increases the bioaccessibility of terebinth coffee antioxidants (36-70%) (p < 0.05). Overall, terebinth coffee + whole milk + sugar formulation was found to contain the highest amount of bioaccessible flavonoid and non-flavonoid compounds (42.71-47.07 mg/100 g).

Effect of Storage and Heat Treatment of Milk Destined for Cheese Production on Its Oxidative Characteristics

The oxidative stability of milk and dairy products is a very interesting topic for the dairy industry due to the growing demand for foods containing bioactive compounds with positive health effects. The aim was to evaluate the oxidative stability of milk intended for cheese production. The effect of storage time, heat pre-treatment, and milk pasteurization temperature on the characteristics of milk and cheese was investigated. The cheese samples were produced with pasteurized milk at both 72 and 77 °C for a time of 15 s using three types of milk: raw fresh milk processed within 48 h of milking, raw stored milk processed within 96 h, and thermized milk that was heat-treated upon arrival at the dairy and processed within 96 h of milking. In total, three repetitions were carried out for each type of milk and pasteurization. Samples of milk before and after pasteurization and cheese at 14 days of storage were analyzed. Antioxidant activity decreased from starting milk to milk after pasteurization to final cheese. The longer storage time of the milk had significant effects on the antioxidant stability of the cheese (64.95 vs. 59.05% of antioxidant activity). Thermization of the milk further reduced the stability of the cheese (54.05% of antioxidant activity). The greater antioxidant stability of fresh milk and cheeses produced with fresh milk is the first result that encourages the production of cheese from a milk that best preserves its original characteristics.

Levels of Total Antioxidant Capacity, sCD14, and TGF-β2 in Breast Milk Plasma of HIV-Infected and HIV-Uninfected Lactating Women

Introduction: Breast milk provides nourishment for infants and nonnutritive bioactive factors, which possess key protective and developmental benefits essential in shaping the infant immune system. However, the impact of human immunodeficiency virus (HIV) and universal antiretroviral therapy (ART) on breast milk nutritional composition and immunity status is not well documented. Objective: The study aimed to compare breast milk immune factors; total antioxidant capacity (TAC), soluble cluster of differentiation 14 (sCD14), and transcription growth factor-beta 2 (TGF-β2) levels between HIV-infected and HIV-uninfected lactating mothers and determine the association between breast milk parameters with HIV disease progression and duration of ART. Methods: Breast milk sCD14, TAC, and TGF-β2 were quantified using enzyme-linked immunosorbent assays and spectrophotometric techniques in 57 HIV-infected breast feeding mothers on option B⁺ therapy for prevention of vertical transmission of HIV and 57 HIV-uninfected mothers at 6 weeks postpartum. The plasma HIV viral load was measured on enrollment and demographic data were recorded. Results: Mean breast milk plasma TAC levels were significantly lower in HIV-infected mothers (1,250.5 ± 280.4 μmolTE/L) compared to the HIV-uninfected participants (1,915.4 ± 326 μmolTE/L; p < 0.001). Soluble CD14 levels in HIV-infected mothers were significantly higher (7,059.3 ± 1,604.7 ng/mL) compared to the HIV-uninfected group (5,670.7 ± 1,268.3 pg/mL; p < 0.001). Similarly, TGF-β2 concentration was also significantly elevated in the HIV-infected mothers (1,426.1 ± 695.4 pg/mL) compared to the HIV-uninfected counterparts (709.2 ± 196.8 pg/mL; p < 0.001). A positive correlation was observed between breast milk plasma sCD14 concentration and the plasma viral load (r = 0.576, p < 0.001), while a significant negative correlation was observed with the duration of ART (r = -0.285, p = 0.032). TAC and TGF-β2 concentrations were inversely correlated with plasma viral load levels. Conclusion: HIV-infected mothers are at risk of oxidative stress. Nutritional intervention with antioxidant rich foods is recommended for this vulnerable group during breastfeeding.

Effect of Yellow Wine Lees Supplementation on Milk Antioxidant Capacity and Hematological Parameters in Lactating Cows under Heat Stress

Simple Summary

The yellow wine lees (YWL), a byproduct of the yellow wine brewing industry which contain high levels of crude protein and anti-oxidative substrates can be a suitable ingredient in dairy rations. Total mixed rations (TMR) containing unfermented/fermented YWL were greater in total phenolic and flavonoid concentrations. Feeding lactating cows under heat stress with TMR containing unfermented or fermented YWL mix can reduce their inflammation response and oxidative stress, as well as improve fatty acid quality and oxidative stability of their milk.

Abstract

Fifteen multiparous lactating Chinese Holstein dairy cows were used in a replicated 3 × 3 Latin Square Design to evaluate the effect of total mixed rations (TMR) containing unfermented and fermented yellow wine lees (YWL) on the oxidative status of heat-stressed lactating cows and the oxidative stability of the milk and milk fatty acids they produced. Cows were fed with three isonitrogenous and isocaloric diets as follows: (1) TMR containing 18% soybean meal, (2) TMR containing 11% unfermented YWL (UM), and (3) TMR containing 11% fermented YWL (FM). The rectal temperature (at 1300 h) and respiratory rate were higher in control cows than in cows fed UM or FM. Both types of YWL were greater in total phenolic and flavonoid contents, reducing power, and radical scavenging abilities than soybean meal. Cows fed UM or FM had higher blood neutrophil, white blood cell, and lymphocyte counts, as well as lower plasma malondialdehyde level, higher plasma superoxide dismutase, glutathione peroxidase, and 2,2-diphenyl-1-picryl-hydrazyl-hydrate levels, and higher total antioxidant capacity in the plasma than those fed control diet. The proportion of milk unsaturated fatty acids was higher and that of saturated fatty acids was lower in UM- and FM-fed animals than in the control animals. Milk from UM- and FM-fed cows had lower malondialdehyde content but higher 2,2-diphenyl-1-picryl-hydrazyl-hydrate content than the control cows. In conclusion, feeding TMR containing UM and FM to cows reduced both the oxidative stress in heat-stressed cows and improved the oxidative capacity of their milk.

Annatto seeds as Antioxidants Source with Linseed Oil for Dairy Cows

Simple Summary

Currently, functional foods are gaining widespread attention. Polyunsaturated fatty acids (PUFA) and antioxidant compounds have beneficial effects on health. It is possible to increase the concentration of these compounds in the milk obtained from dairy cows by manipulating their diets, thereby improving milk quality and consequently the health of animals and humans who consume this milk. Annatto seed (Bixa orellana L.) is a source of antioxidants, whereas linseed oil is rich in omega 3 fatty acid. We evaluated the inclusion of annatto seeds and linseed oil in the diets of dairy cows and their effects on dry matter intake (DMI), nutrient digestibility, milk yield, milk composition and antioxidant capacity in milk and blood. There was no effect of treatment on nutrient digestibility and antioxidant capacity, but the addition of annatto seeds decreased DMI and milk production and linseed oil supplementation reduced milk fat content.

Abstract

This study aimed to evaluate the effects of annatto seeds, linseed oil and their combination on DMI, apparent total tract digestibility, antioxidant capacity and milk composition of dairy cows. Four lactating Holstein cows (120 ± 43 days in milk; 15.98 ± 2.02 kg of milk/day, mean ± SD) were allocated in a 4 × 4 Latin square with a 2 × 2 factorial arrangement (with or without annatto seeds at 15 g/kg of dry matter (DM); with or without linseed oil at 30 g/kg of DM) and provided four different diets: control (no annatto seeds or linseed oil); annatto seeds (15 g/kg of DM); linseed oil (30 g/kg of DM); and a combination of both annatto seeds and linseed oil. Annatto seeds reduced DM intake, and milk yield, protein and lactose, but increased content of fat, total solids and short chain fatty acid, with no effect on total antioxidant capacity of milk. Linseed oil supplementation decreased medium chain fatty acid proportion and n-6/n-3 ratio, conversely it increased long chain fatty acids and n-3 fatty acid content of milk, ether extract intake and total-tract digestibility. Thus, linseed oil supplementation in dairy cow diets improved the milk FA profile but decreased milk fat concentration, whereas annatto seeds did not influence antioxidant capacity and depressed feed intake and milk yield.

The impact of the oxidative status on the reproduction of cows and the calves’ health – a review

The profitability of cattle farming is largely determined by ensuring high-quality breeding animals for replacement and longevity in production. The provision of breeding animals requires adequate fertility of the cowherd and then intensive weight gain in the calf rearing period. For ensuring these demands, many management aspects must be considered. Continuous monitoring of the herd’s health status, including redox status, is essential. This review aims to provide a summary of relevant scientific data published in the last few decades regarding the role of oxidative stress (OS) in infertility of dairy cows and developmental diseases in calves, the major predisposing factors, and possible prevention.

Milk Fat Globule Membrane Proteome and Micronutrients in the Milk Lipid Fraction: Insights into Milk Bioactive Compounds

Milk lipids are composed of milk fat globules (MFGs) surrounded by the milk fat globule membrane (MFGM). MFGM protects MFGs from coalescence and enzymatic degradation. The milk lipid fraction is a “natural solvent” for macronutrients such as phospholipids, proteins and cholesterol, and micronutrients such as minerals and vitamins. The research focused largely on the polar lipids of MFGM, given their wide bioactive properties. In this review we discussed (i) the composition of MFGM proteome and its variations among species and phases of lactation and (ii) the micronutrient content of human and cow’s milk lipid fraction. The major MFGM proteins are shared among species, but the molecular function and protein expression of MFGM proteins vary among species and phases of lactation. The main minerals in the milk lipid fraction are iron, zinc, copper and calcium, whereas the major vitamins are vitamin A, β-carotene, riboflavin and α-tocopherol. The update and the combination of this knowledge could lead to the exploitation of the MFGM proteome and the milk lipid fraction at nutritional, biological or technological levels. An example is the design of innovative and value-added products, such as MFGM-supplemented infant formulas.

Antioxidative Molecules in Human Milk and Environmental Contaminants

Breastfeeding provides overall beneficial health to the mother-child dyad and is universally recognized as the preferred feeding mode for infants up to 6-months and beyond. Human milk provides immuno-protection and supplies nutrients and bioactive compounds whose concentrations vary with lactation stage. Environmental and dietary factors potentially lead to excessive chemical exposure in critical windows of development such as neonatal life, including lactation. This review discusses current knowledge on these environmental and dietary contaminants and summarizes the known effects of these chemicals in human milk, taking into account the protective presence of antioxidative molecules. Particular attention is given to short- and long-term effects of these contaminants, considering their role as endocrine disruptors and potential epigenetic modulators. Finally, we identify knowledge gaps and indicate potential future research directions.

Addition of milk to coffee beverages; the effect on functional, nutritional, and sensorial properties

To date, there exists a debate on the effect of milk added to coffee infusions/beverages concerning the nutritional quality of coffee and the functional properties of its phenolic compounds. Yet, the full nutritional quality and functional properties of a coffee beverage without a significant negative impact on its sensorial profile are highly desired by the consumers. Negative/masking, positive, and neutral effects of milk on the antioxidant activity and bioavailability of coffee phenolics (particularly, chlorogenic acids) have been reported. Some potential factors including the type and amount of milk added, type of coffee beverage, the composition of both milk (protein and fat) and coffee (phenolic compounds), preparation method, assays used to measure antioxidant properties, and sampling size may account for the various reported findings. Interactions between phenolic compounds in coffee and milk proteins could account as the main responsible aspect for the reported masking/negative impact of milk on the antioxidant activity and bioaccessibility/bioavailability of coffee bioactives. However, considering the interactions between milk components and coffee phenolics, which result in the loss of their functionality, the role of milk fat globules and the milk fat globule membrane can also be crucial, but this has not been addressed in the literature so far.HighlightsIn most cases, milk is added to the coffee beverages in several various ways.Effect of milk on the nutritional/functional properties of coffee is controversial.Enough evidence suggests negative effects of milk addition on properties of coffee.Interactions of coffee phenolics and milk proteins could account as the main aspect.The role of milk fat globules and milk fat globule membrane may also be crucial.

Chemical Characteristics and Oxidative Stability of Buffalo Mozzarella Cheese Produced with Fresh and Frozen Curd

Milk and dairy products can have variable contents of antioxidant compounds that contribute to counteract the oxidation of lipids and proteins during processing and storage. The content of active antioxidant compounds is closely linked to their protection by oxidation. Freezing is one of the factors that can reduce antioxidant activity. Freezing of milk or curd is frequently used in case of the seasonality of milk production and/or seasonal increased demand for some products. In this paper, the effect of using frozen curd on the oxidative stability of buffalo Mozzarella cheese was evaluated. Samples of buffalo Mozzarella with different frozen curd content (0%, 5%, 20%, and 50%) were produced and analyzed at one and nine days. Mozzarella cheese with higher frozen curd content had a significant increase in redox potential parallel to the decrease in antioxidant activity, showing less protection from oxidation. Lipid and protein oxidation, expressed respectively by malondialdehyde and carbonyl content, increased significantly with increasing frozen curd. At nine days, carbonyls significantly increased while malondialdehyde content did not vary, showing that during storage, fat was more protected from oxidation than protein. The average carbonyl levels were comparable to those of some cooked cheeses, and the malondialdehyde levels were even lower. The results of this study stimulate the investigation of new strategies to decrease the oxidative damage in cheeses produced in the presence of factors decreasing oxidative stability.

Oxidative Stress Markers and the Retinopathy of Prematurity

Retinopathy of prematurity (ROP) is a leading cause of potentially preventable blindness in low birth weight preterm infants. Several perinatal and postnatal factors contribute to the incomplete maturation of retinal vascularization, leading to oxidative stress damage. Literature data suggest that the lack of equilibrium between pro-oxidants and anti-oxidants plays a key role. In the last decade, there has been an increasing interest in identifying the antecedents of ROP and the relevant pathogenic mechanisms involved. In this context, a panel of biomarkers was investigated in order to achieve early detection of oxidative stress occurrence and to prevent retinal damage. Several nutritional elements have been found to play a relevant role in ROP prevention. At this stage, no conclusive data have been shown to support the usefulness of one biomarker over another. Recently, the Food and Drugs Administration, the European Medicine Agency, and the National Institute of Health proposed a series of criteria in order to promote the inclusion of new biomarkers in perinatal clinical guidelines and daily practice. The aim of the present review is to offer an update on a panel of biomarkers, currently investigated as potential predictors of ROP, highlighting their strengths and weaknesses.

B-Vitamins Determination in Donkey Milk

Background: Donkey milk is used in infant nutrition for the treatment of children affected by cow’s milk protein allergy, thanks to its hypo-allergenicity, mainly due to its protein profile, which is very close to that of human milk. Furthermore, donkey milk is characterized by the presence of a fair amount of bioactive proteins, that may have a positive impact on human health. Despite the presence of numerous articles that describe the chemical composition and nutraceutical properties of donkey milk, few works have been performed to determine its vitamin profile; therefore, the purpose of this work is to give further information on the B-vitamins profile of donkey milk. Methods: B-vitamins have been determined through a reversed-phase liquid chromatography analysis. Results: The results indicated that donkey milk (DM) contains thiamine 0.661 ± 0.26 μM, riboflavin 0.168 ± 0.04 μM, nicotinic acid 18.75 ± 1.92 μM, pyridoxine 5.38 ± 3.3 5μM, and folic acid 0.83 ± 0.08 μM. Conclusions: Donkey milk contains a high quantity of nicotinic acid, known for its lipid-lowering effect, and a good amount of vitamin B6 and folic acid, the latter very important for children’s growth. To notice, vitamin B6 has been determined for the first time in donkey milk.

Identification and Detection of Bioactive Peptides in Milk and Dairy Products: Remarks about Agro-Foods

Food-based components represent major sources of functional bioactive compounds. Milk is a rich source of multiple bioactive peptides that not only help to fulfill consumers 'nutritional requirements but also play a significant role in preventing several health disorders. Understanding the chemical composition of milk and its products is critical for producing consistent and high-quality dairy products and functional dairy ingredients. Over the last two decades, peptides have gained significant attention by scientific evidence for its beneficial health impacts besides their established nutrient value. Increasing awareness of essential milk proteins has facilitated the development of novel milk protein products that are progressively required for nutritional benefits. The need to better understand the beneficial effects of milk-protein derived peptides has, therefore, led to the development of analytical approaches for the isolation, separation and identification of bioactive peptides in complex dairy products. Continuous emphasis is on the biological function and nutritional characteristics of milk constituents using several powerful techniques, namely omics, model cell lines, gut microbiome analysis and imaging techniques. This review briefly describes the state-of-the-art approach of peptidomics and lipidomics profiling approaches for the identification and detection of milk-derived bioactive peptides while taking into account recent progress in their analysis and emphasizing the difficulty of analysis of these functional and endogenous peptides.

Short communication: Effect of purple corn pigment on change of anthocyanin composition and unsaturated fatty acids during milk storage

Unsaturated fatty acids (UFA) in milk give rise to radicals and lead to lipid oxidation during storage, reducing the commercial value of milk. The objective of this study was to observe the effect of anthocyanins from purple corn pigment on the oxidation of UFA in milk. Milk samples were randomly divided into 2 groups: (1) the control (without purple corn pigment) and (2) treatment (0.3% purple corn pigment), using a completely randomized design. The milk samples were placed into plastic tubes and stored at 4°C for a period of 0, 1, 3, and 7 d. Individual anthocyanin composition and UFA were detected by HPLC-mass spectrometry and gas chromatography-mass spectrometry, respectively. The results indicated that pelargonidin (0.258 vs. 0.054 µg/mL), cyanidin (5.550 vs. 1.808 µg/mL), petunidin (0.464 vs. 0.107 µg/mL), delphinidin (2.061 vs. 0.123 µg/mL), and total anthocyanin (8.332 vs. 2.091 µg/mL) significantly decreased in response to increasing storage day. Of interest, purple corn pigment had a significant effect on most of the UFA (C14:1n-5, C16:1n-7, C18:1n-9, C18:2n-6, C18:3n-3, C18:3n-6, C20:2n-6, C20:3n-3, and C20:4n-6), except for C17:1n-7 and C20:3n-6. Specifically, various stronger positive correlations were noted for anthocyanin composition and UFA (pelargonidin and petunidin with C14:1n-5, C17:1n-7, C18:2n-6, C20:2n-6, C20:3n-3, and C20:4n-6; and cyanidin and total anthocyanins with C14:1n-5, C16:1n-7, C17:1n-7). Collectively, the current study suggested that the addition of anthocyanins from purple corn pigment had the potential to maintain UFA concentrations in milk during the storage period.

Relationship between Fatty Acids Composition/Antioxidant Potential of Breast Milk and Maternal Diet: Comparison with Infant Formulas

The fatty acid composition of human breast milk is relevant for the energy, immunity and eicosanoid production in infants. Additionally, the antioxidant properties of foods are essential for human health. Therefore, in the present study we aimed to investigate the relationship between maternal diet and fatty acids composition as well as the antioxidant potential of breast milk from donors to human milk bank of Perugia's hospital, Italy. Results were compared with infant formulas. We observed increased levels of total fatty acids and, in particular, saturated and monounsaturated fatty acids in milk from mothers fed on a vegetable and fruit-rich diet compared with a Mediterranean diet. In the same milk, a reduced antioxidant potential was found. All infant formulas resulted in richer total fatty acid content than human breast milk. Only some formulas were qualitatively similar to breast milk. Of note, the antioxidant potential of the formulas was higher or lower than the human milk with the exception of one sample. The antioxidant potential of four formulas was very high. Dietary supplementation with antioxidants has been shown to have a teratogenic effect and to increase the formation of metastases in adult. There are no data on the effects of excess antioxidants in the infants, but the possibility that they can be harmful cannot be excluded.

Impact of post fermentation cooling patterns on fatty acid profile, lipid oxidation and antioxidant features of cow and buffalo milk set yoghurt

Background

In the manufacturing of set yoghurt, after reaching 4.6 pH, post fermentation cooling is applied to stop the bacterial activity. Depending upon the required textural and flavor attributes, one phase and two phase cooling patterns are accordingly selected. In one phase cooling, temperature of the yoghurt is rapidly decreased below 10 °C using blast freezing and then it is gradually dropped to 4-5 °C. In two phase cooling, temperature of yogurt is rapidly decreased to less than 20 °C and then it is gradually decreased to 4-5 °C. These cooling phases have a significant impact on textural and flavor perspectives of yoghurt. It is necessary to study the impact of industrially adopted cooling patterns on fatty acid profile, antioxidant characteristics, lipid oxidation and sensory characteristics of cow and buffalo milk set yoghurt.

Methods

This experiment was organized in a completely randomized design and every treatment was replicated five times to minimize the variation. Whole cow and buffalo milk without any standardization were converted to set yoghurt (400 g cups) using Strepotococcus thermophillus and Lactobacillus bulgaricus as starter bacteria. After reaching 4.6 pH, cow and buffalo yoghurt samples were exposed to three different cooling patterns. In first trial, samples of cow and buffalo yoghurt were cooled from 43 °C to 25 °C in 1 h and finally cooled to 4-5 °C in another hr. (T₁). In second trial, samples were cooled from 43 °C to 18 °C in 1 hr. and finally cooled down to 4-5 °C in another 1 h. (T₂). In third trial, samples were cooled from 43 °C to 4-5 °C in 2 h (T₁). Alteration in fatty acid profile, total antioxidant capacity, reducing power, free fatty acids, peroxide value, conjugated dienes, vitamin A, E, color and flavor of cow and buffalo yoghurt samples were assessed for 20 days at the frequency of 10 days.

Results

All the three cooling patterns had a non-significant effect on compositional attributes of yoghurt. Buffalo milk yogurt had higher percentage of fat, protein and total solids than yoghurt prepared from cow milk (p < 0.05). At zero day, DPPH free radical scavenging activity of T₂ and T₃ was significantly higher than T₁. This may be due to the longer exposure of T₁ at relatively higher temperature than T₂ and T₃. Effect of storage period up to 10 days was non-significant in T₂ and T_3. Reducing power of cow and buffalo milk yoghurt was also significantly affected by the cooling patterns applied. Reducing power of T₂ and T₃ was considerably higher than T₁ (p < 0.05). At zero-day, total antioxidant capacity of cow and buffalo milk yoghurt in T₃ was 42.6 and 61.4%, respectively. At zero day, total antioxidant capacity of T₂ and T₃ was significantly higher than T₁. Effect of storage on total antioxidant capacity of T₂ and T₃ remained non-significant till 10 days of storage. At zero day, the impact of cooling patterns on fatty acid profile of T₁, T₂ and T₃ was non-significant, whereas, storage period had a marked impact on fatty acid profile. After 10 days, T₁ was considerably different in fatty acids from T₂ and T₃. After 10 days of storage of cow milk yoghurt in T₁, concentration of C_4:0, C_6:0, C_8:0, C_10:0, C_12:0, C_14:0, C_16:0, C_18:0, C_18:1 and C_18:2 decreased by 0.1, 0.11, 0.09, 0.07, 0.21, 0.38, 0.28, 0.27, 0.44 and 0.06%, respectively. Cow milk yoghurt in T₁ after 10 days of storage, concentration of C_4:0, C_6:0, C_8:0, C_10:0, C_12:0, C_14:0, C_16:0, C_18:0, C_18:1 and C_18:2 decreased by 0.07, 0.15, 0.04, 0.17, 0.20, 0.34, 0.27, 0.36 and 0.04%, respectively. After 10 days of storage in T₂ and T₃, loss of fatty acids was 1.2 and 3.61% from C_4:0 to C_10:0, respectively. Milk type had no effect on peroxide value of yoghurt. Cooling of cow and buffalo yoghurt from 43 °C to 25 °C had a pronounced effect on peroxide value. At zero day, peroxide values of cow and buffalo yoghurt in T₁ were 0.32 and 0.33 (MeqO₂/kg). At zero day, peroxide value of cow and buffalo yoghurt in T₂ were 0.24 and 0.26 (MeqO₂/kg). At zero day, peroxide value cow and buffalo yoghurt in T₃ were 0.23 and 0.25 (MeqO₂/kg). Cooling patterns i.e. from 43 °C to 25, 18 and 5 °C (T₁, T₂ and T₃) had a significant effect on the amount of vitamin A and E. Concentration of vitamin A and E in T₁ were significantly less than T₂ and T₃. Cooling patterns had a significant effect on texture, T₁ had a thick texture with higher viscosity as compared to T₂ and T₃. Thickness of yoghurt was in the order of T₁ > T₂ > T₃ with no difference in color and flavor score till 10 days of storage.

Conclusion

Results of current investigation indicated that milk type and post fermentation cooling patterns had a pronounced effect on antioxidant characteristics, fatty acid profile, lipid oxidation and textural characteristics of yoghurt. Buffalo milk based yoghurt had more fat, protein, higher antioxidant capacity and vitamin content. Antioxidant and sensory characteristics of T₁ were optimum till 10 days of storage.

Hygienic-sanitary quality and effect of freezing time and temperature on total antioxidant capacity of human milk

Abstract Knowledge of the hygienic-sanitary quality of raw human milk helps to establish the best storage conditions for the preservation of its nutritional and functional components. Therefore, this study aimed to evaluate the hygienic-sanitary quality of human milk extracted at the mothers’ homes, and to analyze the effect of freezing time and temperature on the milk’s total antioxidant capacity. Milk of five mothers was evaluated individually for Staphylococcus aureus, total aerobic mesophilic counts, mold and yeasts, total and thermotolerant coliforms. The milk pool was stored at -8 °C, -18 °C and -40 °C for 2, 4, 8 and 15 days and analyzed for the total antioxidant capacity by the 2,2-diphenyl-1-picrylhydrazyl free radical and 2,2-azino 3-ethylbenzothiazoline-6-sulfonic acid scavenging methods. The microbiological analyses of the raw human milk samples indicated counts of all the studied microorganisms above the safe limits. Related to the effect of freezing time and temperature on total antioxidant capacity, it was concluded that, regardless of the freezing temperature, a significant reduction occurred on total antioxidant capacity over time and that the lower the storage temperature, the greater its total antioxidant activity.

Changes in fatty acids composition, antioxidant potential and induction period of UHT-treated tea whitener, milk and dairy drink

Background

In developing and developed countries, several versions of safe and shelf-stable Ultra High Temperature, UHT-treated products are manufactured. Terminologies and formulations of UHT-treated tea whitener, milk and dairy drink considerably vary. Comprehensive studies have been performed on UHT-treated milk; however, fatty acids compositional changes and oxidation status of UHT-treated tea whitener and dairy drink at different storage intervals have not been reported in literature.

Methods

UHT-treated tea whitener, milk and dairy drink samples (450 each) of the same manufacturing date were purchased from the market and stored at ambient temperature (25-30 °C) for 90 days. At the time of collection, all the samples were only one week old. Samples of UHT-treated tea whitener, milk and dairy drink were regarded as treatments and every treatment was replicated five times. Chemical composition, fatty acid profile, 2, 2-Diphenyl-1-picrylhydrazyle (DPPH) radical scavenging activity, total antioxidant activity, reducing power, antioxidant activity in linoleic acid system and induction period were determined at 0, 45 and 90 days of storage.

Results

Fat content in freshly collected samples of UHT treated-tea whitener, milk and dairy drink were 6 and 3.5%. UHT treated milk had highest total antioxidant capacity, antioxidant activity in linoleic acid and 2, 2-Diphenyl-1-picrylhydrazyle (DPPH) free radical scavenging activity followed by UHT tea whitener and dairy drink. In freshly collected samples of UHT-treated milk, concentrations vitamin A and E were 0.46 μg/100 g and 0.63 mg/100 g, respectively. UHT-treated tea whitener had the lowest concentrations of vitamin A and E. With the progression of storage period, amount of vitamin A and E decreased. In freshly collected samples, amount of short, medium and unsaturated fatty acids in UHT-treated milk were 10.54, 59.71 and 27.44%, respectively. After 45 days of storage of UHT-treated milk, the loss of short, medium and unsaturated fatty acid was 7%, 7.1 and 5.8%, respectively. After 90 days of storage of UHT-treated milk, the loss of short, medium and unsaturated fatty acid was 8.53, 13.51 and 11.88%, accordingly. After 45 days of storage of UHT-treated tea whitener, the loss of medium and unsaturated fatty acid was 1.6 and 0.99%, respectively. After 90 days of storage, the loss of medium and unsaturated fatty acids were 8.2 and 6.6%, respectively. The induction period of fresh UHT-treated tea whitener, milk and dairy drink was 15.67, .74 and 7.27 h. Strong correlations were recorded between induction period and peroxide value of UHT-treated products.

Conclusion

This investigation disclosed that UHT-treated tea whitener had 6% fat content with no short-chain fatty acids. Antioxidant capacity of UHT-treated milk was higher than dairy drink and tea whitener. Due to the presence of partially hydrogenated fat, oxidative stability of UHT-treated tea whitener was better than UHT-treated milk and dairy drink. Vitamin A and E was not found in UHT-treated tea whitener. For the anticipation of oxidative stability of UHT-treated milk, dairy drink and tea whitener, induction period/ Rancimat method can be used.

Bioprospecting for Bioactive Peptide Production by Lactic Acid Bacteria Isolated from Fermented Dairy Food

With rapidly ageing populations, the world is experiencing unsustainable healthcare from chronic diseases such as metabolic, cardiovascular, neurodegenerative, and cancer disorders. Healthy diet and lifestyle might contribute to prevent these diseases and potentially enhance health outcomes in patients during and after therapy. Fermented dairy foods (FDFs) found their origin concurrently with human civilization for increasing milk shelf-life and enhancing sensorial attributes. Although the probiotic concept has been developed more recently, FDFs, such as milks and yoghurt, have been unconsciously associated with health-promoting effects since ancient times. These health benefits rely not only on the occurrence of fermentation-associated live microbes (mainly lactic acid bacteria; LAB), but also on the pro-health molecules (PHMs) mostly derived from microbial conversion of food compounds. Therefore, there is a renaissance of interest toward traditional fermented food as a reservoir of novel microbes producing PHMs, and “hyperfoods” can be tailored to deliver these healthy molecules to humans. In FDFs, the main PHMs are bioactive peptides (BPs) released from milk proteins by microbial proteolysis. BPs display a pattern of biofunctions such as anti-hypertensive, antioxidant, immuno-modulatory, and anti-microbial activities. Here, we summarized the BPs most frequently encountered in dairy food and their biological activities; we reviewed the main studies exploring the potential of dairy microbiota to release BPs; and delineated the main effectors of the proteolytic LAB systems responsible for BPs release.

Comparison of Oxidative Status of Human Milk, Human Milk Fortifiers and Preterm Infant Formulas

Preterm and low birth weight infants require specific nutrition to overcome the accumulated growth deficit, and to prevent morbidities related to postnatal growth failure. In order to guarantee an adequate nutrient-intake, mother’s own milk, when available, or donor human milk, are usually fortified with additional nutrients, in particular proteins. Fortification with processed ingredients may result in additional intake in oxidative compounds, deriving from extensive heat treatments, that are applied during processing. The aim of the present work was to compare the in vitro antioxidant activity and oxidative compound content conveyed by different preterm infant foods and fortifiers, namely raw and pasteurized human milk, two different preterm infant formulas, three bovine milk-based fortifiers and two experimental donkey milk-based fortifiers. Univariate and multivariate statistical analyses revealed significant differences between the different products. The use of human milk minimizes the intake of dietary oxidative compound in comparison to infant formulas, irrespective of pasteurization or fortification, especially as far as malondialdehyde content is concerned. The addition of fortifiers to human milk increases its antioxidant capacity, and the choice of the protein source (hydrolysed vs. whole proteins) differently impacted the resulting total antioxidant capacity of the diet.

Cow Milk Lactoferrin Possesses Several Catalytic Activities

Lactoferrin (LF) is a Fe³⁺-binding glycoprotein, that was first recognized in milk and then in other epithelial secretions and barrier body fluids to which many different functions have been attributed to LF including protection from iron-induced lipid peroxidation, immunomodulation, cell growth regulation, DNA and RNA binding, as well as transcriptional activation, еtс. The polyfunctional physiological role of LF is still unclear, but it has been suggested to be responsible for primary defense against microbial and viral infections. It was shown previously that human milk LF possesses several enzymatic activities: DNase, RNase, ATPase, phosphatase, and amylase. Analysis of human, cow, horse, buffalo and camel LF showed a highly conserved three-dimensional (3D) structure including only detail differences in the species. Recently, it was shown that similar to human cow LF possesses DNase and RNase activities. Using different methods here we have shown for the first time that LFs from the milk of seven cows of different breeds possess high peroxidase, protease, amylase, protease, and phosphatase activities. Protease activity of cow LFs was activated by Mg²⁺ and Ca²⁺ ions. In contrast to human LFs, ATPase activity was revealed only in three of seven cow LF preparations. The discovery that LF possesses these activities may contribute to understanding the multiple physiological functions of this extremely polyfunctional protein including its protective role against microbial and viral infections.

Color stability of fruit yogurt during storage

This article describes the evaluation of the anthocyanins stability in yogurts with strawberry, sour cherry, and blueberry fruit preparation during 8-week storage period under refrigerated condition. The differences in anthocyanin degradation rate and color changes between stirred yogurts and fruit-on-the-bottom yogurts (fruit preparation was on-the-bottom of package) were compared. Anthocyanin content in fruit yogurts showed a significant decreased during the storage, especially for the first 2 weeks. There were differences in the rate of pigment degradation between yogurt obtained from a different species of fruit. The half-life of the pigments in stirred yogurt with the preparation of strawberry, sour cherry, and blueberry was found to be 5.5, 6.7, and 19.0 weeks, respectively. The addition of fruit preparation on the bottom of yogurt could be used to reduce the pigment degradation during storage. The half-life of anthocyanin in fruit-on-the-bottom yogurts was 39-63% higher than in the blending samples. A significant alteration in the pigment profile during storage of blueberry yoghurt was observed. The proportion of malvidin-glucosides and acylated anthocyanins increased with time of storage, with a concomitant decrease in proportion of petunidin, delphinidin and peonidin derivatives.

Inclusion of Sunflower Oil in the Bovine Diet Improves Milk Nutritional Profile

Milk and its derivatives are important foods that contribute to daily nutrient requirements and improve consumers' health. This study evaluated the effects of supplementing the diet of lactating dairy cows with sunflower oil (SFO), selenium, and vitamin E on the milk's fatty acid profile and fat oxidative stability as well as the acceptability of the milk by consumers. For this purpose, 32 Jersey dairy cows were allocated to four treatment groups for 60 days, as follows: C (control diet); A (3.5 mg/kg DM (dry matter) organic selenium + 2000 IU vitamin E/cow per day); O (4% SFO DM); OA (equal doses of A and O treatments). The inclusion of SFO decreased the contents of 10:0, 10:1, 11:0, 12:0, 12:1, 14:0, and 9c-14:1 fatty acids as well as odd- and branched-chain fatty acids (13:0, iso 13:0, anteiso 13:0, 15:0, iso 15:0, and 17:0). There was also a tendency for 8:0 and 16:0 fatty acid concentrations to decrease when SFO was included in the cows´ diet. SFO decreased the concentration of 10:0 to 15:0 fatty acids in milk. The sum of the conjugated linoleic acids (CLAs), conjugated alpha-linolenic acid intermediates (CLnAs; 18:3 ω6 + 18:3 ω3), and 22:0 fatty acids in milk tended to increase, and there were significant increases in 18:0 and 9c11t-18:2 with SFO. In terms of the effects of SFO on the health-related lipid indices, the atherogenicity index tended to decrease and h/H tended to increase. When cows were supplemented with antioxidants, the concentration of 20:2 fatty acids decreased, the 6 + 7 + 8 + 9t-18:1, 16t-18:1, 20:0, 22:2, and 24:0 fatty acid concentrations increased, and there was a trend for the 22:1 ω9 fatty acid concentration to increase with antioxidants plus oil. There was a tendency for ω6 fatty acids and ω6/ω3 to increase with milk treated with antioxidants plus oil. The oxidative stability of milk was not influenced by the presence of SFO or antioxidants in the diet of dairy cows. Consumers desired the color and mouthfeel of the milk that was treated with SFO. Cows fed with 4% sunflower oil produced milk with an improved fatty acid profile for human nutrition, containing a higher CLA content and an improved ratio of hypocholesterolemic and hypercholesterolemic fatty acids, without increasing the milk's susceptibility to oxidation. The milk was also rated as being more acceptable by consumers.

Effect of milking frequency and α-tocopherol plus selenium supplementation on sheep milk lipid composition and oxidative stability

The aim of this research was to study the effect of milking frequency [once-daily milking (ODM) vs. twice-daily milking (TDM)] and antioxidant (AOX) supplementation on fatty acid (FA) profile and oxidative stability in sheep milk. Sixteen Assaf ewes were used; 8 did not receive any vitamin-mineral supplement (control), and the other 8 received an oral dose of 1,000 IU of α-tocopherol and 0.4 mg of Se daily. The experiment consisted of 2 consecutive periods; the first was 3 wk with TDM of both mammary glands. The second period was 8 wk and consisted of ODM of one mammary gland and TDM of the other gland. All ewes were fed ad libitum the same total mixed ration from lambing and throughout the experiment. There were no differences in plasma or milk Se concentrations between control and AOX ewes. However, plasma and milk α-tocopherol concentrations and AOX capacity were increased in ewes receiving the AOX supplement. Milk FA profile was practically unaffected after 21 d of AOX supplementation. However, after 77 d, AOX supplementation increased the relative percentage of C16:0 and cis-9 C18:1 and reduced the proportions of some saturated FA with less than 16 carbons and cis-9 C12:1. Antioxidant supplementation had no effect on the proportions of conjugated linoleic acid or total polyunsaturated FA (PUFA) but decreased the proportion of trans-7,cis-9 C18:2 and increased that of n-6 C20:3. Once-daily milking did not affect α-tocopherol, Se, or fat resistance to oxidation in milk. Total monounsaturated FA, cis-9 C16:1, and several cis and trans isomers of C18:1 were increased and total saturated FA were decreased in milk from ODM glands. Compared with TDM, ODM increased the proportions of cis-9,cis-12 C18:2 and several isomers of C18:2 and reduced those of cis-9,cis-12,cis-15 C18:3 and some PUFA of 20 and 22 carbons, but total proportion of PUFA was unaffected. Once-daily milking and AOX supplementation modified milk FA profile, but the effects of ODM could be considered of little biological relevance for consumer health. Supplementing ewes with α-tocopherol plus Se could be considered an effective strategy to improve plasma AOX status and reduce milk fat oxidation without substantial changes in the milk FA profile.

Antioxidant properties of Milk and dairy products: a comprehensive review of the current knowledge

Milk and dairy products are integral part of human nutrition and they are considered as the carriers of higher biological value proteins, calcium, essential fatty acids, amino acids, fat, water soluble vitamins and several bioactive compounds that are highly significant for several biochemical and physiological functions. In recent years, foods containing natural antioxidants are becoming popular all over the world as antioxidants can neutralize and scavenge the free radicals and their harmful effects, which are continuously produced in the biological body. Uncontrolled free radicals activity can lead to oxidative stresses, which have been implicated in breakdown of vital biochemical compounds such as lipids, protein, DNA which may lead to diabetes, accelerated ageing, carcinogenesis and cardiovascular diseases. Antioxidant capacity of milk and milk products is mainly due to sulfur containing amino acids, such as cysteine, phosphate, vitamins A, E, carotenoids, zinc, selenium, enzyme systems, superoxide dismutase, catalase, glutathione peroxidase, milk oligosaccharides and peptides that are produced during fermentation and cheese ripening. Antioxidant activity of milk and dairy products can be enhanced by phytochemicals supplementation while fermented dairy products have been reported contained higher antioxidant capacity as compared to the non-fermented dairy products. Literature review has shown that milk and dairy products have antioxidant capacity, however, information regarding the antioxidant capacity of milk and dairy products has not been previously compiled. This review briefly describes the nutritional and antioxidant capacity of milk and dairy products.

Micronutrient content and antioxidant enzyme activities in human breast milk

Breast milk contains micronutrients that function as cofactors of antioxidant enzymes. High concentrations of iron (Fe) and copper (Cu) can increase the production of reactive oxygen species (ROS). This study aimed to assess the relationship between the activity of antioxidant enzymes (superoxide dismutase (SOD), catalase, glutathione peroxidase (GPx), glutathione reductase (GR) and glutathione S-transferase (GST)) and the concentration of the micronutrients Fe, Cu and zinc (Zn) in breast milk. Breast milk samples were collected from 108 mothers (7-10 days postpartum, transitional milk). The samples were grouped into three groups according to the number of pregnancies (one, two and three or more pregnancies), also grouped according to the body mass index (BMI) suggested by the World Health Organization (WHO) in underweight, normal weight, overweight and obese. Breast milk Fe, Cu and Zn concentrations were determined by atomic absorption spectrophotometry and the activity of the antioxidant enzymes was determined by spectrophotometry. An increase in GPx, SOD and GST activities in relation to the number of pregnancies was found (p = 0.05, p = 0.04 and p < 0.01, respectively). An inverse relationship between GST activity and BMI was found (p = 0.05). A positive correlation was observed between Cu and Zn concentrations (r = 0.52, p < 0.05). A negative correlation was found between Cu concentration and catalase activity (r = -0.22, p < 0.05); Fe content was negatively correlated with GPx and GST activities (r = -0.32, r = -0.22, respectively, p < 0.05). The activities of antioxidant enzymes (GPx, SOD and GST) may be affected by the number of pregnancies and contribute to prevent oxidation of nutritional molecules in breast milk.

Removal of antibiotics from water and waste milk by ozonation: kinetics, byproducts, and antimicrobial activity

The use of antibiotics in the dairy farming for curing and growth promotion results in the production of massive quantities of non-recyclable wastewater by the conventional purification techniques. Additionally, waste milk is produced during the drug withholding periods, which is not suitable for human or animal consumption and cause huge economic loss as well as present serious environmental waste. This study was designed to investigate the decomposition of various antibiotic compounds in un-buffered aqueous solutions and milk samples by ozonation process. Commonly administered broad-spectrum antibiotics such as amoxicillin, doxycycline, ciprofloxacin, and sulphadiazine were selected as model examples in the current investigation. Gradual exposure of these antibiotics to increasing ozone gas concentration induced increasing removal percentages of the antibiotics in spiked water and milk samples. The removal reached 95% across all the tested treated antibiotics with ozone dose as low as 75 mg L^-1. It was noted that the removal of antibiotics in milk samples is more efficient with faster rate constants. This was attributed to the self-buffering characteristic of milk that maintains the neutral pH, keeping the amine groups un-protonated and more reactive towards the electrophilic attack by the molecular ozone. ¹H NMR as well as HPLC experiments support the near complete removal of antibiotics and indicated the break down to simpler and more soluble fragments of acidic nature. Bacterial growth experiments, conducted with E. coli, and milk ageing experiments provided clear evidences that the resulting decomposition byproducts lack both toxicity effect and antimicrobial activity. This study provides a viable route to remove hazardous materials, which contribute to a growing issue of antibiotic resistance of pathogenic bacteria.