Heat-labile Component Research Articles

Effect of pulsed electric field processing on microbial and enzyme inactivation in blended plant-based milk alternatives: A case study on a microbial challenge test for a non-presterilized oat-based beverage enriched with pea protein

Microbial and enzyme inactivation by pulsed electric field (PEF) treatment was assessed in a blended plant-based milk alternative (PBMA) containing oats and pea protein without the application of presterilization. This was conducted to investigate a novel approach that permits PEF process validation for PBMA containing heat-labile components (protein and starch). Continuous PEF processing at moderate field strengths (9–10 kV/cm) combined with mild preheating (30–45 °C) for 25 s was applied over a range of specific energy inputs (77–245 kJ/L). Selective plating permitted bacterial enumeration of inoculated surrogate organisms, despite the presence of natural microbial contaminants in the non-presterilized product. A minimum 5-log reduction of inoculated surrogates Escherichia coli and Listeria innocua alongside native microbiota was identified after preheating to 35–45 °C followed by PEF at 192–215 kJ/L. α-amylase activity was reduced by up to 89% during a similar PEF treatment (205 kJ/L, 40 °C preheating). Overall, continuous PEF combined with mild preheating temperature was shown to achieve microbial inactivation in the pea protein enriched PBMA in compliance with current food safety regulations. Industrial relevancePresterilization is typically applied prior to conducting microbial challenge testing on food products to validate novel pasteurization treatments according to current regulatory requirements that a minimum 5-log reduction of relevant inoculated food pathogens must be achievable. However, for a variety of blended PBMA containing heat-labile proteins, presterilization is not advisable as the occurrence of irreversible changes in the product quality linked to protein coagulation and phase separation will affect the inactivation efficacy during subsequent microbial challenge testing. Hence, an alternative approach is presented utilizing a non-presterilized PBMA and thorough microbiological analysis, combining non-selective and selective plating techniques. This allows an identification of PEF treatment parameter with a minimum 5-log reduction of inoculated surrogate organisms alongside naturally present microbial contaminants. This may serve as a valuable guideline for stakeholders in the food industry when addressing the efficacy of novel preservation treatments such as PEF in PBMA products with similar heat-induced product stability challenges.

Non-thermal techniques for microbiological safety, nutritional preservation, and enhanced efficiency in dairy processing

The ongoing era of adopted lifestyle among humans involves shortcuts in every aspect, and a similar trend can be observed in food processing and preservation, especially in dairy preparation. Thus, lots of non-thermal processes including high-pressure processing (HPP), ultrasound (US) treatment, pulsed electric fields (PEF), ultraviolet (UV) light and oscillating magnetic fields (OMF), etc. have been invented. By inactivating bacteria, these non-thermal processes keep food's sensory and nutritional quality while also preventing thermal degradation of food components near ambient temperatures. Non-thermal techniques can effectively preserve a food's nutraceuticals and functional potential, while simultaneously ensuring microbiological safety and maintaining the integrity of its bioactive components. During the thermal processing, several heat-labile components of milk and milk products may be lost In contrast, non-thermal processes are gentler compared to thermal treatments, making them preferred choices that avoid compromising nutritional value. It has been observed that non-thermal technology can increase processing efficiency and microstructure through constituent interactions, alteration of enzyme activity, and development of hypoallergenic products. However, in order to use thermal technologies profitably, the risk of operation, equipment cost, technological compatibility, and goal of processing the product must be thoroughly assessed prior to using these processes. Non-thermal processes can also be combined with other strategies like the addition of bio-preservatives or modified atmospheric packaging etc., to enhance the antimicrobial effects. Keywords: Non-thermal processes; Microbiological safety; Dairy processing; Bioactive components; Bioactive compounds; Enzyme activity; Nutritional quality; Bio-preservatives.

Interaction of γ-Polyglutamic Acid/Polyethyleneimine/Plasmid DNA Ternary Complexes with Serum Components Plays a Crucial Role in Transfection in Mice.

Typical examples of non-viral vectors are binary complexes of plasmid DNA with cationic polymers such as polyethyleneimine (PEI). However, problems such as cytotoxicity and hemagglutination, owing to their positively charged surfaces, hinder their in vivo use. Coating binary complexes with anionic polymers, such as γ-polyglutamic acid (γ-PGA), can prevent cytotoxicity and hemagglutination. However, the role of interactions between these complexes and serum components in in vivo gene transfer remains unclear. In this study, we analyzed the contribution of serum components to in vivo gene transfer using PEI/plasmid DNA binary complexes and γ-PGA/PEI/plasmid DNA ternary complexes. In binary complexes, heat-labile components in the serum greatly contribute to the hepatic and splenic gene expression of the luciferase gene. In contrast, serum albumin and salts affected the hepatic and splenic gene expression in the ternary complexes. Changes in physicochemical characteristics, such as increased particle size and decreased absolute values of ζ-potential, might be involved in the enhanced gene expression. These findings would contribute to a better understanding of in vivo non-viral gene transfer using polymers, such as PEI and γ-PGA.

Chlorophyll fluorescence-based high-throughput phenotyping facilitates the genetic dissection of photosynthetic heat tolerance in African (Oryza glaberrima) and Asian (Oryza sativa) rice.

Rising temperatures and extreme heat events threaten rice production. Half of the global population relies on rice for basic nutrition, and therefore developing heat-tolerant rice is essential. During vegetative development, reduced photosynthetic rates can limit growth and the capacity to store soluble carbohydrates. The photosystem II (PSII) complex is a particularly heat-labile component of photosynthesis. We have developed a high-throughput chlorophyll fluorescence-based screen for photosynthetic heat tolerance capable of screening hundreds of plants daily. Through measuring the response of maximum PSII efficiency to increasing temperature, this platform generates data for modelling the PSII-temperature relationship in large populations in a small amount of time. Coefficients from these models (photosynthetic heat tolerance traits) demonstrated high heritabilities across African (Oryza glaberrima) and Asian (Oryza sativa, Bengal Assam Aus Panel) rice diversity sets, highlighting valuable genetic variation accessible for breeding. Genome-wide association studies were performed across both species for these traits, representing the first documented attempt to characterize the genetic basis of photosynthetic heat tolerance in any species to date. A total of 133 candidate genes were highlighted. These were significantly enriched with genes whose predicted roles suggested influence on PSII activity and the response to stress. We discuss the most promising candidates for improving photosynthetic heat tolerance in rice.

A universal method of preparing high yield and N riched porous carbon by carbonizing coal tar pitch in air for supercapacitor

A universal method for the preparation of high-yield and high N content porous carbide is reported. Nine type composite salts are assisted to carbonize coal tar pitch (CTP) in muffle furnace in air atmosphere. The mechanism of composite salt assisted carbonization of CTP is studied systematically. The composite salt is consist of heat labile ammonium salts component that can decompose producing gas at low temperature and stalbe inorganic salts component that can generate molten salt at high carbonization temperature. The two components can protect CTP in the whole carbonization process in air. These composite salts play the triple role of protection CTP from oxidation and combustion, activator and heteroatom source. The carbon yield is up to 50 wt%, and the scale-up experiment can also get high yield. The porous carbide prepared by NH4Cl/(NH4PO3)n has a high N content (10.39 at%) and high yield (56.0 wt%), and it exhibits an excellent specific capacitance (374.3 F g−1). In addition, the assembled ammonium ion supercapacitor with the prepared porous carbide and (NH4)3PO4 electrolyte shows high energy density (24.1 Wh kg−1). The work uncovers a universal and feasible way to prepare high carbon yield porous carbon materials with large scale industrial production in air.

Evaluating the efficacy of non-thermal microbial load reduction treatments of heat labile food components for in vitro fermentation experiments.

Increasingly, in vitro simulated colon fermentations are being used as a pre-clinical step to assess the impacts of foods and drugs on the gut microbiota in a cost-effective manner. One challenge in such systems is that they are potentially susceptible to the influences of contaminating microbes in test materials. Simulated gastric and intestinal digestion can relieve some of these concerns, however, live microbes may remain that can confound analysis. Autoclave treatment of test materials is the surest way to eliminate these microbes but presents problems when using heat labile components such as resistant starch. In this study, liquid chemical sterilant alternatives to moist heat sterilization were explored for treating pulse flours for use during in vitro simulated colon fermentation. Key attributes considered in chemical selection were accessibility, impact on treated food components, and effectiveness of the treatments for reducing microbial load. Three chemicals were selected for evaluation, bleach, alcohol, and hydrogen peroxide, at varying concentrations. Flours chosen for testing were from green lentil, field pea, chickpea, or sprouted green lentil. All treatments significantly reduced microbial loads, though there were still detectable levels of microbes after alcohol treatments. Furthermore, in vitro simulated colon fermentations of the treated pulses showed minimal difference from the untreated control both in terms of microbial composition and short chain fatty acid production. Scanning electron microscopy showed minimal impact of sterilization treatments on the gross structure of the pulse flours. Together these results suggest that bleach and hydrogen peroxide treatments can be effective nonthermal treatments to eliminate contaminating microbes in pulse flours without causing significant damage to starch and other fermentable substrates. This is thus also a promising treatment method for other starchy food substrates, though further testing is required.

A novel heat treatment protocol for human milk.

Human milk (HM) is the recommended nutrition for premature infants, but it may require processing to ensure microbial safety. The current standard is Holder pasteurisation (HoP), i.e. heating milk at 62.5 ± 0.5°C for 30 min, which eliminates bacteria but destroys heat labile bioactive HM components. We aimed to test an alternative thermal method, high-temperature short-time (HTST) pasteurisation using a modified Holder pasteurisation platform as this method has shown to preserve proteins in experimental HM flow pasteurisers. We analysed the ability of this batch process to eliminate bacterial species and to retain alkaline phosphatase, secretory immunoglobulin A and lactoferrin in HM. HTST at 81°C/5 s was as effective as HoP in bacterial count reduction while the retention of bioactive components was only improved at 62°C/5 s as compared to 72°C/5 s and HoP. HTST is a promising alternative to HoP but an optimal temperature-time combination needs to be determined for each technical platform separately.

Shiitake dermatitis: experience of the Poison Control Centre Network in France from 2014 to 2019

Objective Shiitake mushrooms (Lentinus edodes) are an edible fungus, initially grown in Japan and China that are increasingly marketed in Europe. We previously presented 15 shiitake dermatitis cases reported to Poison Control Centres (PCCs) in France from January 2000 to December 2013. The aim of this study was to describe changes in the number of shiitake dermatitis cases since 2014, and to better describe the clinical characteristics and risk factors of this reaction. Case series This observational study is a retrospective review of cases in the French PCCs database between 1 January 2014 and 31 December 2019. Out of 125 shiitake exposures, we identified 59 cases of dermatitis: sex ratio of 1.80 M/F; ages ranging from 19 to 69 years (median: 39 years). Dermatitis occurred after raw or undercooked shiitake consumption (e.g., from the wok, in soup, or on pizza). The rash appeared 1–168 h (median: 48 h) after shiitake ingestion. Linear, erythematous, urticarial papules and plaques developed across the trunk, arms, and legs within a few hours and persisted for 1–40 d (median 10 d). The amount of shiitake eaten (low vs. medium vs. high) significantly increased the duration of dermatitis (median days 4 vs. 7 vs. 15, respectively; p = .007). In all, 38 patients received corticosteroids, antihistamine drugs, or both without demonstrated benefit. All patients made a complete recovery. Conclusions The mechanism of shiitake dermatitis is thought to involve lentinan, a heat-labile polysaccharide component. Inadequate cooking clearly seems to be a driver of the occurrence of shiitake dermatitis. This study highlighted a dose-dependent response, suggesting a partial toxic mechanism or a th1-type hypersensitivity mechanism. Treatment is focused on symptom management. Health professionals and the general population should be aware of both the risk associated with inadequately cooked shiitake consumption and the favourable prognosis of this still poorly known toxic dermatitis.

Characterization and functional analysis of hybrid pearl gentian grouper (Epinephelus lanceolatus♂ × Epinephelus fuscoguttatus♀) complement C3 against Cryptocaryon irritans infection

Pearl gentian grouper is a new aquacultural hybrid resulted from breeding of female tiger grouper (Epinephelus fuscogutattus) and male giant grouper (E. lanceolatus). Our preliminary study found that pearl gentian grouper exhibits less susceptible to the primary infection of Cryptocaryon irritans, which is an important parasitic ciliate in marine aquaculture, indicated that pearl gentian grouper might own a strong innate immune system. Complement system play key roles in innate immunity, whether pearl gentian grouper's complement component contribute for the defensing against the C. irritans infection remain unclear. In the present study, we found that C. irritans can be immobilized by untreated serum but not heat-treated serum from pearl gentian grouper, suggested that the heat-labile components in serum are responsible for the immobilization of C. irritans. Moreover, we cloned and characterized the encoding sequence of pearl gentian grouper complement C3 (PGC3), a key component in complement system. We also found that the expression level of PGC3 was increased in infected grouper serum when compared with that of control grouper. Furthermore, the binding of PGC3 on the surface of C. irritans trophonts located on the grouper skin was detected. These data suggested that pearl gentian grouper's complement system indeed play roles in the immune response against the C. irritans infection.

Inhibition of Streptococcus mutans biofilms with bacterial-derived outer membrane vesicles

BackgroundBiofilms are microbial communities surrounded by a self-produced extracellular matrix which protects them from environmental stress. Bacteria within biofilms are 10- to 1000-fold more resistant to antibiotics, making it challenging but imperative to develop new therapeutics that can disperse biofilms and eradicate infection. Gram-negative bacteria produce outer membrane vesicles (OMV) that play critical roles in communication, genetic exchange, cargo delivery, and pathogenesis. We have previously shown that OMVs derived from Burkholderia thailandensis inhibit the growth of drug-sensitive and drug-resistant bacteria and fungi.ResultsHere, we examine the antibiofilm activity of Burkholderia thailandensis OMVs against the oral biofilm-forming pathogen Streptococcus mutans. We demonstrate that OMV treatment reduces biofilm biomass, biofilm integrity, and bacterial cell viability. Both heat-labile and heat-stable components, including 4-hydroxy-3-methyl-2-(2-non-enyl)-quinoline and long-chain rhamnolipid, contribute to the antibiofilm activity of OMVs. When OMVs are co-administered with gentamicin, the efficacy of the antibiotic against S. mutans biofilms is enhanced.ConclusionThese studies indicate that bacterial-derived OMVs are highly effective biological nanoparticles that can inhibit and potentially eradicate biofilms.

Therapeutic Targeting of the Complement System: From Rare Diseases to Pandemics.

The complement system was discovered at the end of the 19th century as a heat-labile plasma component that “complemented” the antibodies in killing microbes, hence the name “complement.” Complement is also part of the innate immune system, protecting the host by recognition of pathogen-associated molecular patterns. However, complement is multifunctional far beyond infectious defense. It contributes to organ development, such as sculpting neuron synapses, promoting tissue regeneration and repair, and rapidly engaging and synergizing with a number of processes, including hemostasis leading to thromboinflammation. Complement is a double-edged sword. Although it usually protects the host, it may cause tissue damage when dysregulated or overactivated, such as in the systemic inflammatory reaction seen in trauma and sepsis and severe coronavirus disease 2019 (COVID-19). Damage-associated molecular patterns generated during ischemia-reperfusion injuries (myocardial infarction, stroke, and transplant dysfunction) and in chronic neurologic and rheumatic disease activate complement, thereby increasing damaging inflammation. Despite the long list of diseases with potential for ameliorating complement modulation, only a few rare diseases are approved for clinical treatment targeting complement. Those currently being efficiently treated include paroxysmal nocturnal hemoglobinuria, atypical hemolytic-uremic syndrome, myasthenia gravis, and neuromyelitis optica spectrum disorders. Rare diseases, unfortunately, preclude robust clinical trials. The increasing evidence for complement as a pathogenetic driver in many more common diseases suggests an opportunity for future complement therapy, which, however, requires robust clinical trials; one ongoing example is COVID-19 disease. The current review aims to discuss complement in disease pathogenesis and discuss future pharmacological strategies to treat these diseases with complement-targeted therapies.Significance StatementThe complement system is the host’s defense friend by protecting it from invading pathogens, promoting tissue repair, and maintaining homeostasis. Complement is a double-edged sword, since when dysregulated or overactivated it becomes the host’s enemy, leading to tissue damage, organ failure, and, in worst case, death. A number of acute and chronic diseases are candidates for pharmacological treatment to avoid complement-dependent damage, ranging from the well established treatment for rare diseases to possible future treatment of large patient groups like the pandemic coronavirus disease 2019.

Amaranthus spinosus L. inhibits spontaneous and dexamethasone-induced apoptosis in murine primary splenocytes

Amaranthus spinosus L. (thorny amaranth) is traditionally selected to be an anti-diabetic herb in Taiwan. This study assessed the immuno-modulatory effects of wild A. spinosus water extract (WASWE) on spontaneous and dexamethasone (DEX)-induced apoptosis in murine primary splenocytes. The cultured splenocytes treated with WASWE products were harvested and analyzed to assess their apoptotic status according to DNA fragmentation by flow cytometry and agarose gel electrophoresis. The results showed WASWE inhibited the spontaneous and DEX-induced apoptosis of splenocytes. Furthermore, both WASWE and its activated charcoal-treated sample administered at concentration of 1.250 mg/mL inhibited intracellular protein levels of p53 (an apoptotic inducer protein) and p80 (a form of tumor necrosis factor (TNF) receptor), which are involved in apoptosis. The present study suggested the existence of a heat-labile anti-apoptotic component with high molecular weight in WASWE.

The Beneficial Effect of Farm Milk Consumption on Asthma, Allergies, and Infections: From Meta-Analysis of Evidence to Clinical Trial

The low prevalence of asthma and allergies in farm children has partially been ascribed to the consumption of raw cow's milk. A literature search identified 12 publications on 8 pertinent studies. A meta-analysis corroborated the protective effect of raw milk consumption early in life (<1 to 5 years, according to study) on asthma (odds ratio [OR], 0.58; 95% CI, 0.49-0.69), current wheeze (OR, 0.66; 95% CI, 0.55-0.78), hay fever or allergic rhinitis (OR, 0.68; 95% CI, 0.57-0.82), and atopic sensitization (OR, 0.76; 95% CI, 0.62-0.95). The effect particularly on asthma was observed not only in children raised on farms (OR, 0.62; 95% CI, 0.58-0.82) but also in children living in rural areas but not on a farm (OR, 0.60; 95% CI, 0.48-0.74). This demonstrates that the effect of farm milk consumption is independent of other farm exposures and that children not living on a farm can theoretically profit from this effect. Because of the minimal but real risk of life-threatening infections, however, consumption of raw milk and products thereof is strongly discouraged. Raw farm milk and industrially processed milk differ in many instances including removal of cellular components, manipulation of the fat fraction, and various degrees of heating. Preliminary evidence attributes the effect to heat-labile molecules and components residing in the fat fraction. The Milk Against Respiratory Tract Infections and Asthma (MARTHA) trial is currently testing the protective effect of microbiologically safe, minimally processed cow's milk against standard ultra-heat-treated milk in children from 6 months to 3 years with the primary outcome of an asthma diagnosis until age 5 years. If successful, this approach might provide a simple but effective prevention strategy.

Effect of Blanching on Enzyme Activity and Bioactive Compounds of Blackberry

ABSTRACT The inactivation of peroxidase and polyphenol oxidase and the degradation of phenolic compounds, anthocyanins, and antioxidant activity in blackberry were investigated during blanching in water at 80-90 °C, and in steam, from 0 to 10 minutes. The enzyme kinetics indicated the presence of two isoenzymes with different thermal stability, following two-phase model, in which the reaction rate constant increased with increasing temperature for both the heat labile and heat resistant component. The phenolic compounds also followed a biphasic pattern, indicating a more heat resistant fraction, and the rate constants increased with increasing temperature. For the antioxidant activity and anthocyanins, the first order kinetic model (R2>0.982) indicated an increase in degradation rate constants with temperature, from 0.050 to 0.137min-1 for DPPH, 0.085 to 0.285min-1 for ABTS, and 0.017 to 0.052 min-1 for anthocyanins.

Elaboration of orange juice concentrate by vacuum‐assisted block freeze concentration

Vacuum-assisted freeze concentration is a technology allows produces high-quality concentrates and thus achieves the protection of heat-labile components in fresh samples. The aim of this study was to investigate the use of vacuum-assisted block freeze concentration in the elaboration of orange juice. Fresh juice was unidirectional frozen at −20 °C for 12 hr and vacuum was performed at 80 kPa. The results showed, 20 min of suction, an increased in concentrated fraction and ascorbic acid content by 4.4 and 4.1 times, respectively, compared with the fresh juice. The cryoconcentrates were darker than the initial sample, with ΔE* values >10 CIELAB units in all treatments. In addition, achieved high values with 84% in efficiency and 35% of concentrate. It was concluded that vacuum in freeze concentration of orange juice was effective for obtaining a high-quality concentrate with a higher concentration of solids and ascorbic acid content compared with the fresh sample. Practical applications The block freeze concentration assisted by vacuum allows producing an orange juice concentrate with excellent physicochemical properties (increase solid content, darker color, and higher ascorbic acid content compared with the initial sample), which can draw attention to consumers looking foods rich in bioactive components for a healthy life. The vacuum as an assisted technique improve the process parameters of block freeze concentration, obtaining promissory results for adaptability to commercial scale in the elaboration of concentrated orange juice.

열처리 조리방법이 마늘의 항산화 활성과 이화학적 특성에 미치는 영향

한국인이 마늘을 섭취할 때 주로 사용하는 조리방법으로 8종의 마늘을 준비하여 조리 조건이 마늘의 항산화 활성과 이화학적 특성에 미치는 영향을 살펴보았다. 열처리 강도가 높은 조리법일수록 마늘의 수분 손실이 컸으며, 명도는 낮아지고 황색도는 높아지는 전형적 갈변 현상을 나타내었다. 특히 명도가 가장 낮았던 프라잉과 팬 프라잉으로 조리된 마늘에서는 수용성 고형분 함량 역시 유의적으로 낮아 조리온도가 높을수록 수용성 저분자 물질로부터 불용성 고분자 중합물질을 형성하는 비효소적 갈변반응이 더 가속화되었음을 시사해주었다. 한편 조리된 마늘은 생마늘보다 thiosulfinates 함량이 낮았으며, 이는 열처리에 의해 thiosulfinates가 polysulfides로 분해되었거나, 열전달 매체를 사용한 삶기, 프라잉, 팬 프라잉으로 조리된 마늘에서는 이들 물질이 열전달 매체로 용출되었을 가능성을 시사해주었다. 전자레인지로 조리된 마늘은 다른 마늘보다 유기산과 thiosulfinates, 플라보노이드 성분들이 상대적으로 많이 보유되어 있었으며, 이는 에너지가 낮고 조리시간이 짧은 전자레인지 가열방식에 의해 마늘 속 열에 약한 성분들이 상대적으로 덜 분해된 결과로 볼 수 있다. 높은 온도에서 조리된 마늘들은 총 환원력과 금속 소거능이 높은 경향을 나타내었으며, 이는 색도 결과에 의해 시사된 것과 같이 환원력을 지닌 갈변반응의 중간물질과 최종물질들이 고온 조리 시 더 활발히 생성된 결과로 해석되었다. 물과 기름을 열전달 매체로 하여 조리된 마늘에서는 총 환원력과 플라보노이드 함량이 상대적으로 낮은 경향을 나타내었다. 그러나 생마늘과 조리된 마늘에서 측정된 총 환원력과 플라보노이드 정량 결과는 DPPH 라디칼 소거능 결과와는 다소 일치하지 않았다. 이는 환원성 물질들의 총량이 증가하였음에도 불구하고 우수한 항산화 활성을 지닌 일부 열에 불안정한 플라보노이드와 페놀 화합물들이 조리 중 감소하였을 가능성을 말해준다. 따라서 조리 중 마늘 내부에서 분해 혹은 새로이 생성될 수 있는 개별 환원성 물질들의 조성과 항산화 활성 비교에 대한 후속연구가 필요할 것으로 생각한다.

Study the possibility of use of extracts of the mushroom Boletus edulis in the production of functional dairy products

Fruiting bodies of mushrooms are rich in proteins. The most rich in proteins is Boletus edulis (white mushroom), and total protein contains all the essential amino acids. The low bioavailability of proteins Boletus edulis stimulates the search for ways to improve. One way to improve the bioavailability of nutrients of Boletus edulis is an extraction. This article presents the results of studies of extracts of white mushroom (Boletus edulis), obtained using different methods of processing the chopped dry fruiting body. The effect of physical and biotechnological parameters on the efficiency of the extraction of proteins was studied. The spectral characteristics and protein content of the obtained extracts were determined. It is shown that the ultrasonic extraction activation leads to the most efficient protein extraction(an increase of 9.5%). It is also significantly affected by the duration of extraction. The use of the enzyme preparation in the investigated ratios do not have a positive impact, however, enzymatic treatment in conjunction with ultrasound treatment increased the efficiency of 13.5%, showing the complex diffusion processes in the fruiting bodies of mushrooms. Increasing the length of the extraction, despite the high content of protein in the extract, is impractical because of the risk of bacterial contamination of high-nutritive extract. Increasing the temperature of the process has no significant effect on the protein content, but it reduces the value of the extract, due to the destruction of heat-labile components, which include vitamins and secondary metabolites. The extract application rate for curd product was determined. For the test samples organoleptic characteristics and titratable acidity were determined. The most appropriate dose of the extract in the manufacture of making curd product is 15% by weight of the finished product.

Novel O-linked methylated glycan antigens decorate secreted immunodominant glycoproteins from the intestinal nematode Heligmosomoides polygyrus

Glycan molecules from helminth parasites have been associated with diverse biological functions ranging from interactions with neighbouring host cell populations to down-modulation of specific host immunity. Glycoproteins secreted by the intestinal nematode Heligmosomoides polygyrus are of particular interest as the excretory–secretory products (termed HES) of this parasite contain both heat-labile and heat-stable components with immunomodulatory effects. We used MALDI-TOF-MS and LC–MS/MS to analyse the repertoire of N- and O-linked glycans released from Heligmosomoides polygyrus excretory–secretory products by PNGase A and F, β-elimination and hydrazinolysis revealing a broad range of structures including novel methylhexose- and methylfucose-containing glycans. Monoclonal antibodies to two immunodominant glycans of H. polygyrus, previously designated Glycans A and B, were found to react by glycan array analysis to a methyl-hexose-rich fraction and to a sulphated LacDiNAc (LDN; GalNAcβ1–4GlcNAc) structure, respectively. We also analysed the glycan repertoire of a major glycoprotein in Heligmosomoides polygyrus excretory–secretory products, VAL-2, which contains many glycan structures present in Heligmosomoides polygyrus excretory–secretory products including Glycan A. However, it was found that this set of glycans is not responsible for the heat-stable immunomodulatory properties of Heligmosomoides polygyrus excretory–secretory products, as revealed by the inability of VAL-2 to inhibit allergic lung inflammation. Taken together, these studies reveal that H. polygyrus secretes a diverse range of antigenic glycoconjugates, and provides a framework to explore the biological and immunomodulatory roles they may play within the mammalian host.

Influence of heat-labile serum components in the presence of OmpA on the outer membrane of Salmonella gallinarum.

Salmonella gallinarum is the causative agent of fowl typhoid. Being a Gram-negative bacteria, its outer membrane proteins (OMP) can be regulated by different microenvironments. S. gallinarum was cultured under the following conditions: nutrient broth (NB), NB supplemented with serum from specific pathogen-free birds (NBS) and NB with serum incubated at 56 °C prior to incubation with the bacteria (NBSD); OMP were subsequently extracted. Several changes were observed in the apparent expression of OMP, mainly a decrease in an OMP with a size of 30 kDa, approximately, under the NBS condition. In contrast, the same event was not observed in NB and NBSD when using one- and two-dimensional polyacrylamide gels (SDS-PAGE). Using the OMP with a size of 30 kDa, approximately, as antigen in indirect ELISA, we were able to differentiate serum from healthy and vaccinated birds, as well as birds infected with S. gallinarum and S. enteritidis. The amino-terminal of this protein was sequenced, showing 100 % identity with OmpA of S. typhimurium. Subsequently, we designed primers to amplify the gene by PCR. The partial sequence of the amplified gene showed 100 % identity with OmpA of S. gallinarum. (1) Heat-labile serum components influence the presence of OmpA in the OM of S. gallinarum; (2) by the way of ELISA, OmpA allows to specifically differentiate healthy from diseased birds.

Pulsed electric field processing of egg products: a review.

Thermal processing ensures safety and enhances the shelf-life of most of the food products. It alters the structural-chemical composition, modifies heat labile components, as well as affects the functional properties of food products. This has driven the development of non-thermal food processing techniques, primarily for extending the shelf-life of different food products. These techniques are currently also being evaluated for their effects on product processing, quality and other safety parameters. Pulsed electric field (PEF) is an example of non-thermal technique which can be applied for a variety of purpose in the food processing industry. PEF can be used for antimicrobial treatment of various food products to improve the storability or food safety, for extraction and recovery of some high-value compounds from a food matrix or for stabilization of various food products through inactivation of some enzymes or catalysts. Research on the application of PEF to control spoilage or pathogenic microorganisms in different egg products is being currently focused. It has been reported that PEF effectively reduces the activity of various microorganisms in a variety of egg products. However, the PEF treatment also alters the structural and functional properties to some extent and there is a high degree of variability between different studies. In addition to integrating findings, the present review also provides several explanations for the inconsistency in findings between different studies related to PEF processing of egg products. Several specific recommendations for future research directions on PEF processing are well discussed in this review.