Effect of processing on nutritive values of milk protein

Bioactive peptides in dry-cured ham: A comprehensive review of preparation methods, metabolic stability, safety, health benefits, and regulatory frameworks

Dry-cured hams contain abundant bioactive peptides with significant potential for the development of functional foods. However, the limited bioavailability of food-derived bioactive peptides has hindered their utilization in health food development. Moreover, there is insufficient regulatory information regarding bioactive peptides and related products globally. This review summarizes diverse bioactive peptides derived from dry-cured ham and by-products originating from various countries and regions. The bioactivity, preparation techniques, bioavailability, and metabolic stability of these bioactive peptides are described, as well as the legal and regulatory frameworks in various countries. The primary objectives of this review are to dig deeper into the functionality of dry-cured ham and provide theoretical support for the commercialization of bioactive peptides from food sources, especially the dry-cured ham.

Changes of the volatile compounds and odors in one-stage and three-stage infant formulas during their secondary shelf-life

The odor of infant formula changes due to alterations in its volatile composition during the shelf life. However, there is currently a lack of research on whether the odor changes in infant formula during the secondary shelf life, which refers to the period of repeated opening and usage in daily life. This study used headspace solid-phase microextraction (HS-SPME) coupled with gas chromatography-electrostatic orbitrap high-resolution mass spectrometry (GC-Orbitrap-MS) to investigate the volatile composition changes in one-stage and three-stage infant formulas during different stages (0 day, 3 days, and 7 days during the secondary shelf-life, i.e. simulated daily use). A total of 32 volatiles were identified, including nine aldehydes, seven ketones, four alcohols, three furans, two sulfur compounds, two esters, and five terpenoids. Of these, 16 compounds changed significantly in one-stage samples and 23 compounds in three-stage samples within 7 days of the secondary shelf-life. Further the odor of the three-stage infant formula samples was found changed substantially after 3 days of simulated use by using the triangle test. This study highlighted the considerable alterations in volatile compound composition and sensory changes during the simulated daily use and provided valuable insights for consumers in selecting and using infant formula products, as well as a new perspective for enterprises to improve the sensory quality of their products.

Non-thermal techniques as an approach to modify the structure of milk proteins and improve their functionalities: a review of novel preparation

BACKGROUND

Milk proteins (MPs) have been widely used in the food industry due to their excellent functionalities. However, MPs are thermal-unstable substances and their functional properties are easily affected by heat treatment. Emerging non-thermal approaches (i.e., high-pressure homogenization (HPH), ultrasound (US), pulsed electric field (PEF)) have been increasingly popular. A detailed understanding of these approaches' impacts on the structure and functionalities of MPs can provide theoretical guidance for further development to accelerate their industrialization.

SCOPE AND APPROACH

This review assesses the mechanisms of HPH, US and PEF technologies on the structure and functionalities of MPs from molecular, mesoscopic and macroscopic levels, elucidates the modifications of MPs by these theologies combined with other methods, and further discusses their existing issues and the development in the food filed.

KEY FINDINGS AND CONCLUSIONS

The structure of MPs changed after HPH, US and PEF treatment, affecting their functionalities. The changes in these properties of MPs are related to treated-parameters of used-technologies, the concentration of MPs, as well as molecular properties. Additionally, these technologies combined with other methods could obtain some outstanding functional properties for MPs. If properly managed, these theologies can be tailored for manufacturing superior functional MPs for various processing fields.

A comprehensive review on glycation and its potential application to reduce food allergenicity

Food allergens are a major concern for individuals who are susceptible to food allergies and may experience various health issues due to allergens in their food. Most allergenic foods are subjected to heat treatment before being consumed. However, thermal processing and prolonged storage can cause glycation reactions to occur in food. The glycation reaction is a common processing method requiring no special chemicals or equipment. It may affect the allergenicity of proteins by altering the structure of the epitope, revealing hidden epitopes, concealing linear epitopes, or creating new ones. Changes in food allergenicity following glycation processing depend on several factors, including the allergen's characteristics, processing parameters, and matrix, and are therefore hard to predict. This review examines how glycation reactions affect the allergenicity of different allergen groups in allergenic foods.

Determination of A1 and A2 β-Casein in Milk Using Characteristic Thermolytic Peptides via Liquid Chromatography-Mass Spectrometry

β-casein, a protein in milk and dairy products, has two main variant forms termed as A1 and A2. A1 β-casein may have adverse effects on humans. The fact that there is only one amino acid variation at the 67th position between A1 and A2 β-casein makes it difficult to distinguish between them. In this study, a novel method using characteristic thermolytic peptides is developed for the determination of A1 and A2 β-casein in milk. Firstly, caseins extracted from milk samples are thermolytic digested at 60 °C without any denaturing reagents required for unfolding proteins, which simplifies the sample pretreatment procedure. The characteristic thermolytic peptides (i.e., fragments 66-76 and 59-76 for A1 and A2 β-casein, respectively) selected to specifically distinguish A1 and A2 β-casein only have eleven or eighteen amino acid moieties. Compared with tryptic characteristic peptides with a length of 49 amino acid moieties, these shorter thermolytic characteristic peptides are more suitable for LC-MS analysis. This novel method, with the advantages of high specificity, high sensitivity, and high efficiency, was successfully applied for the analysis of six milk samples collected from a local supermarket. After further investigation, it is found that this method would contribute to the development of A2 dairy products for a company and the quality inspection of A2 dairy products for a government.

A comprehensive review on infant formula: nutritional and functional constituents, recent trends in processing and its impact on infants' gut microbiota

Human milk is considered the most valuable form of nutrition for infants for their growth, development and function. So far, there are still some cases where feeding human milk is not feasible. As a result, the market for infant formula is widely increasing, and formula feeding become an alternative or substitute for breastfeeding. The nutritional value of the formula can be improved by adding functional bioactive compounds like probiotics, prebiotics, human milk oligosaccharides, vitamins, minerals, taurine, inositol, osteopontin, lactoferrin, gangliosides, carnitine etc. For processing of infant formula, diverse thermal and non-thermal technologies have been employed. Infant formula can be either in powdered form, which requires reconstitution with water or in ready-to-feed liquid form, among which powder form is readily available, shelf-stable and vastly marketed. Infants' gut microbiota is a complex ecosystem and the nutrient composition of infant formula is recognized to have a lasting effect on it. Likewise, the gut microbiota establishment closely parallels with host immune development and growth. Therefore, it must be contemplated as an important factor for consideration while developing formulas. In this review, we have focused on the formulation and manufacturing of safe and nutritious infant formula equivalent to human milk or aligning with the infant's needs and its ultimate impact on infants' gut microbiota.

The Impact of Pulsed Electric Fields on Milk's Macro- and Micronutrient Profile: A Comprehensive Review

Consumers around the world are attracted to products with beneficial effects on health. The stability, functionality, and integrity of milk constituents are crucial determinants of product quality in the dairy industry. Milk contains macronutrients and micronutrients that aid in a wide range of physiological functions in the human body. Deficiencies of these two types of nutrients can confine growth in children and increase the risk of several diseases in adults. The influence of pulsed electric fields (PEF) on milk has been extensively reviewed, mostly concentrating on the inactivation of microbes and enzymes for preservation purposes. Therefore, the information on the variations of milk macro- and micronutrients treated by PEF has yet to be elucidated and it is imperative as it may affect the functionality, stability, and integrity of the milk and dairy products. In this review, we describe in detail the introduction, types, and components of PEF, the inactivation mechanism of biological cells by PEF, as well as the effects of PEF on macro- and micronutrients in milk. In addition, we also cover the limitations that hinder the commercialization and integration of PEF in the food industry and the future outlook for PEF. The present review consolidates the latest research findings investigating the impact of PEF on the nutritional composition of milk. The assimilation of this valuable information aims to empower both industry professionals and consumers, facilitating a thorough understanding and meticulous assessment of the prospective adoption of PEF as an alternative technique for milk pasteurization.

Alteration of the allergenicity of cow's milk proteins using different food processing modifications

Milk is an essential source of protein for infants and young children. At the same time, cow's milk is also one of the most common allergenic foods causing food allergies in children. Recently, cow's milk allergy (CMA) has become a common public health issue worldwide. Modern food processing technologies have been developed to reduce the allergenicity of milk proteins and improve the quality of life of patients with CMA. In this review, we summarize the main allergens in cow's milk, and introduce the recent findings on CMA responses. Moreover, the reduced effects and underlying mechanisms of different food processing techniques (such as heating, high pressure, γ-ray irradiation, ultrasound irradiation, hydrolysis, glycosylation, etc.) on the allergenicity of cow's milk proteins, and the application of processed cow's milk in clinical studies, are discussed. In addition, we describe the changes of nutritional value in cow's milk treated by different food processing technologies. This review provides an in-depth understanding of the allergenicity reduction of cow's milk proteins by various food processing techniques.

Bioactive peptides from meat: Current status on production, biological activity, safety, and regulatory framework

By-products of the meat processing industry which are often discarded as waste are excellent protein substrates for producing bioactive peptides through enzymatic hydrolysis. These peptides have tremendous potential for the development of functional food products but there is scanty information about the regulations on bioactive peptides or products in various parts of the world. This review focuses on the diverse bioactive peptides identified from different meat and meat by-products, their bioactivity and challenges associated in their production as well as factors limiting their effective commercialization. Furthermore, this report provides additional information on the possible toxic peptides formed during production of the bioactive peptides, which enables delineation of associated safety and risk. The regulatory framework in place for bioactive peptide-based foods in different jurisdictions and the future research directions are also discussed. Uniform quality, high cost, poor sensory acceptance, lack of toxicological studies and clinical evidence, paltry stability, and lack of bioavailability data are some of the key challenges hindering commercial advancement of bioactive peptide-based functional foods. Absorption, distribution, metabolism and excretion (ADME) studies in rodents, in vitro genotoxicity, and immunogenicity data could be considered as absolute pre-requisites to ensure safety of bioactive peptides. In the absence of ADME and genotoxicity data, long term usage to evaluate safety is highly warranted. Differences in legislations among countries pose challenge in the international trade of bioactive peptides-based functional foods. Harmonization of regulations could be a way out and hence further research in this area is encouraged.

Nutritional Quality of Three Iron-Rich Porridges Blended with Moringa oleifera, Hibiscus sabdariffa, and Solanum aethiopicum to Combat Iron Deficiency Anemia among Children

Iron deficiency anemia has been a public health issue in children under five years of age in Cameroon. Very limited attempts have been carried out to develop an iron-rich food using local ingredients. The study aimed at developing functional porridges from local ingredients for iron-deficient children aged 6–23 months. Leaves of Moringa oleifera, Hibiscus sabdariffa, and Solanum aethiopicum were harvested as sources of iron, dried, ground into powder, and screened for their water and iron contents. Each vegetable powder was mixed with the other ingredients (dry whole milk, brown sugar, yellow maize flour, and refined soybean oil) to obtain three powdered porridges using linear programming (LP). Protein, lipid, carbohydrate, iron, energy, water, ash, crude fiber, and vitamin C contents, expressed in dry weight, were determined on powdered porridges. Powdered porridges were cooked in boiled water (ratio 2 : 7%w/w) for 5 min. Hedonic tests were conducted using cooked porridges with 50 untrained panelists. Leaf powders contained iron varying between 5.39 and 5.98 mg/100 g. LP models of the three porridges satisfied the nutritional requirements of children aged 6–23 months in terms of iron, lipid, protein, carbohydrate, and caloric daily intake. Protein, lipid, carbohydrate, iron, energy, water, ash, crude fiber, and vitamin C contents were, respectively, between 11.37 and 13.83 g/100g, 30.79 and 32.94 g/100g, 45.97 to 46.81 g/100g, 5.14 and 6.15 mg/100g, 509.93 and 517.48 kcal/100g, 6.42 to 7.62 g/100g, 2.20 and 2.88 g/100g, 1.65 and 2.44 g/100g, and 46.49 and 163.38 mg/100g. The cost of powdered porridges varied between 0.40 and 0.49 USD/100g. The sensory analysis showed that the moringa leaf-based porridge (82%) was the most appreciated followed by eggplant leaf-based porridge (80%) and folere leaf-based porridge (70%). Hence, these results showed that moringa, folere, and eggplant leaves can be used in functional foods to alleviate iron deficiency among children aged 6–23 months.

Structural and chemical changes induced by temperature and pH hinder the digestibility of whey proteins

In the food and feed industry, protein extraction is commonly performed under acid or basic conditions, combined with heat, in order to increase the extraction yield. Under severe processing conditions, proteins may undergo molecular modifications. Here, the effects of heating (30, 60, 90 °C) at different pH values (2, 7, 9, 11, 13) were evaluated on commercial whey proteins, used as a simplified protein model. The main structure and chemical modifications concerning protein aggregation, hydrolysis, insolubilization, amino acid degradation and racemization were investigated in detail. Using in vitro static models, the degree of protein hydrolysis and the released peptides were determined after the digestive process. Accumulation of molecular modifications was mostly observed after basic pH and high temperatures treatments, together with a marked decrease and modification of the digestibility profile. Instead, protein digestibility increased in neutral and acidic conditions in a temperature-dependent manner, even if some modification in the structure occurs.

An updated review on food-derived bioactive peptides: Focus on the regulatory requirements, safety, and bioavailability

Food-derived bioactive peptides (BAPs) are recently utilized as functional food raw materials owing to their potential health benefits. Although there is a huge amount of scientific research about BAPs' identification, purification, characterization, and physiological functions, and subsequently, many BAPs have been marketed, there is a paucity of review on the regulatory requirements, bioavailability, and safety of BAPs. Thus, this review focuses on the toxic peptides that could arise from their primary proteins throughout protein extraction, protein pretreatment, and BAPs' formulation. Also, the influences of BAPs' length and administration dosage on safety are summarized. Lastly, the challenges and possibilities in BAPs' bioavailability and regulatory requirements in different countries were also presented. Results revealed that the human studies of BAPs are essential for approvals as healthy food and to prevent the consumers from misinformation and false promises. The BAPs that escape the gastrointestinal tract epithelium and move to the stomach are considered good peptides and get circulated into the blood using different pathways. In addition, the hydrophobicity, net charge, molecular size, length, amino acids composition/sequences, and structural characteristics of BAPs are critical for bioavailability, and appropriate food-grade carriers can enhance it. The abovementioned features are also vital to optimize the solubility, water holding capacity, emulsifying ability, and foaming property of BAPs in food products. In the case of safety, the possible allergenic and toxic peptides often exhibit physiological functions and could be produced during the hydrolysis of food proteins. It was also noted that the production of iso-peptides bonds and undesirable Maillard reaction might occur during protein extraction, sample pretreatments, and peptide synthesis.

Effect of Processing of Whey Protein Ingredient on Maillard Reactions and Protein Structural Changes in Powdered Infant Formula

The most widely used whey protein ingredient in an infant formula (IF) is the whey protein concentrate (WPC). The processing steps used in the manufacturing of both a powdered IF and a WPC introduce protein modifications that may decrease the nutritional quality. A gently processed whey protein ingredient (serum protein concentrate; SPC) was manufactured and used for the production of a powdered IF. The SPC and the SPC-based IF were compared to the WPC and the powdered WPC-based IF. Structural protein modifications were evaluated, and Maillard reaction products, covering furosine, α-dicarbonyls, furans, and advanced glycation end products, were quantified in the IFs and their protein ingredients. IF processing was responsible for higher levels of protein modifications compared to the levels observed in the SPC and WPC. Furosine levels and aggregation were most pronounced in the WPC, but the SPC contained a high level of methylglyoxal, revealing that other processing factors should be considered in addition to thermal processing.

Enzymatic hydrolysis and microbial fermentation: The most favorable biotechnological methods for the release of bioactive peptides

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Peptide release methods influence its bioactivity by generating different sequences.

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The absorption, toxicity and taste of peptides is influenced by the production method.

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The most used methods are enzymatic hydrolysis and microbial fermentation.

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The most used methods are biotechnological and differ in their process.

Bioactive peptides are biomolecules derived from proteins. They contain anywhere from 2 to 20 amino acids and have different bioactivities. For example, they have antihypertensive activity, antioxidant activity, antimicrobial activity, etc. However, bioactive peptides are encrypted and inactive in the parental protein, so it is necessary to release them to show their bioactivity. For this, there are different methods, where biotechnological methods are highly favorable, highlighting enzymatic hydrolysis and microbial fermentation.

The choice of the method to be used depends on different factors, which is why it is essential to know about the process, its principle, and its advantages and disadvantages. The process of peptide release is critical to generate various peptide sequences, which will produce different biological effects in the hydrolysate. This review focuses on providing extensive information on the enzymatic method and microbial fermentation to facilitate selecting the method that provides the most benefits.

Recent advancement in functional properties and toxicity assessment of plant-derived bioactive peptides using bioinformatic approaches

Nowadays, biopeptides have gained considerable interest by the food industries, given their potent biological effect on health. BPs, when released from the sequence of their precursors by proteolytic enzymes, improved the various physiological functions of the body. Diabetic and hypertension are the two most common life-threatening diseases linked to dietary patterns. Angiotensin-converting enzyme (ACE) (hypertension-responsible glycoprotein) and dipeptidyl peptidase IV (DPP-IV) (proline-specific dimeric aminopeptidase) have been widely used as molecular target sites of action of bioactive compounds possessing antihypertensive and antidiabetic effects. Although, BPs possess considerable biological properties (antioxidant, antimicrobial, antiviral, immunomodulating, antiproliferative, antidiabetic, and antihypertensive effects), most of them possess inherent lacunae such as toxicity, allergenicity, bitterness, and lack of detailed mechanistic investigation, limiting their commercial application. The present review provides an overview on various sources of bioactive peptides, conventional and modern methods of extraction, and challenges that need to be addressed before its commercial application. In addition, bioinformatics' role in exploring the functional properties of biopeptides (ACE and DPP-IV inhibitory effects) toxicity, the target site of action with special reference to plant-based peptides, and recent burgeoning proficiencies in biopeptide research have been discussed.

Enzymatic crosslinking and food allergenicity: A comprehensive review

Food allergy has become a major global public health concern. In the past decades, enzymatic crosslinking technique has been employed to mitigate the immunoreactivity of food allergens. It is an emerging non-thermal technique that can serve as a great alternative to conventional food processing approaches in developing hypoallergenic food products, owing to their benefits of high specificity and selectivity. Enzymatic crosslinking via tyrosinase (TYR), laccase (LAC), peroxidase (PO), and transglutaminase (TG) modifies the structural and biochemical properties of food allergens that subsequently cause denaturation and masking of the antigenic epitopes. LAC, TYR, and PO catalyze the oxidation of tyrosine side chains to initiate protein crosslinking, while TG initiates isopeptide bonding between lysine and glutamine residues. Enzymatic treatment produces a high molecular weight crosslinked polymer with reduced immunoreactivity and IgE-binding potential. Crosslinked allergens further inhibit mast cell degranulation due to the lower immunostimulatory potential that assists in the equilibration of T-helper (Th)1/Th2 immunobalance. This review provides an updated overview of the studies carried out in the last decade on the potential application of enzymatic crosslinking for mitigating food allergenicity that can be of importance in the context of developing hypoallergenic/non-allergenic food products.

Effect of biofilm on the survival of Staphylococcus aureus isolated from raw milk in high temperature and drying environment

Microbial contamination in dairy products is a momentous factor affecting food safety. Studies have shown that Staphylococcus aureus, which is an important causative agent of a range of infectious and foodborne diseases, may remain in raw milk after a series of complex processing processes. Although most S. aureus possess biofilm formation capacity, there are few studies concerning the role of biofilm formation of this bacterium in stress tolerance and longtime survival in the dairy products. In this study, we selected 5 S. aureus (RMSA1, RMSA2, RMSA3, RMSA4 and RMSA5) isolates from raw milk and investigated their virulence and biofilm characteristics. Results from biofilm assays showed that all 6 S. aureus strains (5 dairy isolates and 1 human-derived model strain NCTC8325) could form complete biofilms in vitro. The reverse transcription-PCR experiments confirmed that multiple genes related to virulence factors and biofilm formation were expressed in the 6 strains. Furthermore, we simulated the high temperature (at 60 °C for 30 min) and drying pressure (at 37 °C for 24 h) during dairy processing to detect the survival rate of strains culturedunderbiofilm or planktonic condition. The data showed that under high temperature and dry conditions, the survival rates of strains cultured under biofilm conditions were much higher than that of strains cultured under planktonic conditions. In addition, the adversity resistance associated with biofilm formation was more obvious in the milk-isolated strains compared with strain NCTC8325. This study provides evidence regarding the mechanisms of stress resistance of S. aureus strains isolated from raw milk and contribute to prevention of dairy product contamination caused by this bacterium.

Influence of Ultra-Heat Treatment on Properties of Milk Proteins

Milk can be considered one of the primary sources of nutrients for the mammalian neonate. Therefore, milk and milk-based products, such as infant formula, whey protein isolate, different varieties of cheese, and others are prepared to meet the nutritional requirements of the consumer. Due to its significant nutritional components and perishable nature, a variety of pathogenic microorganisms can grow and multiply quickly in milk. Therefore, various heat treatments can be employed for the improvement of the shelf life of milk. In comparison to pasteurized milk, due to excessive and severe heating, UHT milk has a more cooked flavor. During storage, changes in the physicochemical properties of milk can lead to off-flavors, undesirable browning, separation of fat, sediment formation, or gelation during the subsequent storage. Several important factors such as processing parameters, time-temperature abuse (storage condition), and packaging type also influence the quality characteristics and consumer acceptance of the milk; however, the influence of heat treatments on milk protein is inconstant. The major protein modifications that occur during UHT treatment are denaturation and aggregation of the protein, and chemical modifications of its amino acids. These UHT-induced protein alterations can change digestibility and the overall biological influence of the intake of these proteins. Therefore, this review is focused on the influence of UHT on the physicochemical and structural attributes of milk proteins during storage. There are many indications of milk proteins present in the UHT milk, and milk products are altered during processing and storage.

A comparative study on the effects of boiling and ultrasonication on radical scavenging activity, casein particle size, and whiteness of milk

Background and Aim

Different processing treatments affect the functional properties of milk. This study aimed to evaluate the effects of boiling and ultrasonication on radical scavenging activity, micellar casein particle size, and the whiteness of milk.

Materials and Methods

Milk was subjected to boiling and ultrasonication treatments. Then, the micellar casein size and the whiteness of the milk were evaluated using L-Value- intensity of whiteness and the radical scavenging capacity of the milk was evaluated using 1,1-diphenyl-2-picrylhydrazyl method.

Results

The radical scavenging activity of the milk was found to be reduced during the different processing treatments, but this decrease was non-significant for the ultrasonication treatment (p>0.05). However, a significant reduction in radical scavenging activity (p<0.05) was observed for the boiled milk. Micellar casein size reduction was observed after both treatments, and boiling had a significant effect (p<0.05) on the micellar casein particle size. We found that the whiteness of skim milk was significantly decreased after boiling treatment, but was not significantly decreased after ultrasonication. Ultrasonication had a non-significant effect on the whiteness of ultrasonicated milk which was observed.

Conclusion

Ultrasonicated milk had a very non-significant effect on the antioxidant activity (radical scavenging activity) of milk, whereas the effect of boiling was significant. Ultrasonication treatment increases the shelf-life of milk while retaining its bioactive properties.

Identification of Quinone Degradation as a Triggering Event for Intense Pulsed Light-Elicited Metabolic Changes in Escherichia coli by Metabolomic Fingerprinting

Intense pulsed light (IPL) is becoming a new technical platform for disinfecting food against pathogenic bacteria. Metabolic changes are deemed to occur in bacteria as either the causes or the consequences of IPL-elicited bactericidal and bacteriostatic effects. However, little is known about the influences of IPL on bacterial metabolome. In this study, the IPL treatment was applied to E. coli K-12 for 0–20 s, leading to time- and dose-dependent reductions in colony-forming units (CFU) and morphological changes. Both membrane lipids and cytoplasmic metabolites of the control and IPL-treated E. coli were examined by the liquid chromatography-mass spectrometry (LC-MS)-based metabolomic fingerprinting. The results from multivariate modeling and marker identification indicate that the metabolites in electron transport chain (ETC), redox response, glycolysis, amino acid, and nucleotide metabolism were selectively affected by the IPL treatments. The time courses and scales of these metabolic changes, together with the biochemical connections among them, revealed a cascade of events that might be initiated by the degradation of quinone electron carriers and then followed by oxidative stress, disruption of intermediary metabolism, nucleotide degradation, and morphological changes. Therefore, the degradations of membrane quinones, especially the rapid depletion of menaquinone-8 (MK-8), can be considered as a triggering event in the IPL-elicited metabolic changes in E. coli.

Identification of circRNA-Associated-ceRNA Networks Involved in Milk Fat Metabolism under Heat Stress

Summer temperatures are generally high in Southern China, and cows are likely to suffer a heat stress reaction. Heat stress will have a negative impact on the performance of dairy cows; however, the mechanism by which high temperature affects lactation is not clear. CircRNA is a type of non-coding RNA discovered in recent years, which performs a crucial function in many biological activities. However, the effects of circRNA on lactation function of dairy cows under heat stress is unknown. The present study aimed to explore the expression levels of circRNA in the mammary gland tissue of cows under heat stress. Firstly, we collected blood and milk samples of summer and winter cows and evaluated lactation performance using serum indicators, milk production, and milk composition. Incorporating the calculation of the temperature and humidity index, we conformed the heat stress status of cows in summer. Heat stress increased the concentration of HSP70 and decreased the concentration of SOD and PRL. Heat stress not only reduced milk yield but also affected milk quality, with milk lactose and milk protein decreasing with increased temperature. The analysis of the fatty acid composition in summer milk found significantly reduced concentrations of unsaturated fatty acids, especially long-chain unsaturated fatty acids. Sequencing of the cow's mammary gland transcriptome revealed that compared to the appropriate temperature (ST) group, the heat stress (HS) group had a total of 2204 upregulated and 3501 downregulated transcripts. GO enrichment and KEGG pathway analysis showed that these genes were mainly related to milk fat metabolism. In addition, 19 upregulated and 19 downregulated circRNA candidates were found in response to heat stress. We used Pearson's test to establish the correlation of circRNA-mRNA and identified four pairs of circRNA-miRNA networks between four circRNAs, six miRNAs, and the CD36 gene. In this study, we revealed the possible role of circRNAs in lactation of dairy cows and identified that circRNA-miRNA-mRNA networks might exist in the cow's mammary glands, providing valuable experience for dairy lactation and milk quality.

Effects of the vat pasteurization process and refrigerated storage on the bovine milk metabolome

This study is the first to investigate the evolution of cow milk metabolites throughout the vat pasteurization process and storage using untargeted metabolomics based on a multiplatform approach. Nuclear magnetic resonance and ultraperformance liquid chromatography-quadrupole time-of-flight mass spectrometry were used for fingerprinting water-soluble nutritional compounds, and headspace gas chromatography-mass spectrometry was used to fingerprint the volatile organic compounds. This study demonstrated that vat pasteurization was an efficient and mild means of milk preservation resulting in only minor changes to the metabolites. The pasteurized milk samples exhibited a stable metabolome during the first 8 d of refrigerated storage. However, at the latter stage of storage, the concentrations of pantothenic acid and butyrylcarnitine decreased, whereas some fatty acids, organic acids, α-AA, peptides, and ketones increased. These selected metabolites that changed during milk storage could be used as potential biomarkers to track the storage conditions of pasteurized cow milk.

How the heat treatment affects the constituents of infant formulas: a review

Abstract Breast milk as the children’s primary source of nutrition fulfills the babies’ needs and can also provide immune protection. In some cases, when mothers are not able to breastfeed, an equivalent substitute is required. Nowadays, the best substitutes of the human breast milk are infant formulas. Different technological routes may be designed to produce infant formulas according to the main challenges: the compromise between food safety and heat treatment damage. This article aimed to review the current scientific knowledge about how heat treatment affects the macro and micronutrients of milk, extrapolating the expected effects on infant formulas. The covered topics were: The definition and composition of infant formulas, industrial methods of infant formulas production, the effects of heat treatment on milk macro and micronutrients.

Amino Acid and Secondary Structure Integrity of Sonicated Milk Proteins

This study investigated the effect of low-frequency (20kHz) and high-frequency (414kHz) ultrasound treatment on the amino acid and secondary structural integrity of dairy proteins. Sonicated skim milk proteins were hydrolysed and analysed with reverse-phase high-performance liquid chromatography to investigate the amino acid content of the processed samples. It was successfully demonstrated that both low-frequency and high-frequency ultrasound did not adversely affect the amino acid content, even after prolonged extreme processing conditions (6h, 355kHz). This finding was supplemented with protein secondary structure data (Fourier-transform (FT)-IR secondary derivatives of the amide I band, 1700–1600cm−1) that showed that ultrasound was capable of causing structural modifications to the dairy proteins. This study shows that ultrasound can be used to influence protein–protein interactions in skim milk via alterations to the secondary structure without degrading the amino acids in the proteins.

Higher Polygenetic Predisposition for Asthma in Cow's Milk Allergic Children

Cow’s milk allergy (CMA) is an early-onset allergy of which the underlying genetic factors remain largely undiscovered. CMA has been found to co-occur with other allergies and immunological hypersensitivity disorders, suggesting a shared genetic etiology. We aimed to (1) investigate and (2) validate whether CMA children carry a higher genetic susceptibility for other immunological hypersensitivity disorders using polygenic risk score analysis (PRS) and prospective phenotypic data. Twenty-two CMA patients of the Dutch EuroPrevall birth cohort study and 307 reference subjects were genotyped using single nucleotide polymorphism (SNP) array. Differentially genetic susceptibility was estimated using PRS, based on multiple P-value thresholds for SNP inclusion of previously reported genome-wide association studies (GWAS) on asthma, autism spectrum disorder, atopic dermatitis, inflammatory bowel disease and rheumatoid arthritis. These associations were validated with prospective data outcomes during a six-year follow-up in 19 patients. We observed robust and significantly higher PRSs of asthma in CMA children compared to the reference set. Association analyses using the prospective data indicated significant higher PRSs in former CMA patients suffering from asthma and related traits. Our results suggest a shared genetic etiology between CMA and asthma and a considerable predictive sensitivity potential for subsequent onset of asthma which indicates a potential use for early clinical asthma intervention programs.

Application of ohmic heating for concentration of milk

The concentration of milk through evaporation is the most commonly employed unit operation for the production of a wide array of traditional and industrial dairy products. Major problems associated with thermal evaporation are a loss of aroma, flavor and color change. Ohmic heating (OH) has an immense potential for rapid and uniform heating of liquid, semi-solid and particulate foods, yielding microbiologically safe and high-quality product. The effect of ohmic heating on physico-chemical, rheological, sensorial and microbial properties during concentration of cow milk, buffalo milk and mixed milk (50:50) was studied and compared to conventional evaporation. OH significantly increased free fatty acids (FFA), apparent viscosity, hydroxymethylfurfural (HMF) content, instrumental color values i.e. redness (a*) and yellowness (b*) values. However, pH value and whiteness (L*) of the concentrated milk decreased significantly. OH caused a drastic reduction in microbiological counts and treated milk can be kept for a longer period.