Identification of Gastrointestinal Digestion Stable Antihypertensive Fish Peptides from Atlantic Mackerel (Scomber scombrus).

High blood pressure has been recognized as one of the main risk factors of cardiometabolic syndrome by health organizations. Hypertension is medicated by various classes of synthetic drugs; however, adverse effects have repeatedly been reported. Moreover, natural alternatives such as fish peptides have been effective in the treatment and prevention of hypertension. The aim of our study was to fractionate and identify antihypertensive peptides. Fractions were produced using different techniques of solid-phase extraction (SPE), pressure-driven ultrafiltration (UF), and electro04dialysis with UF membrane. According to our results, the hydrophobic fraction of SPE (IC50 5 µg) was the most potent anti-angiotensin converting enzyme (ACE) product. Findings of the study suggest that the separation technique plays an important role in the isolation efficiency of antihypertensive biopeptides. Importantly, the hydrophobic fraction's activity was retained through a static model of an in vitro gastrointestinal digestion system. In conclusion, polarity regardless of charge and size was the most important factor for anti-ACE activity of an Atlantic mackerel biopeptide. In addition, the presence of leucine at either of the extremities (C- or N-terminal) and/or leucine-rich motifs could well explain the hypotensive effect of our active fraction.

Effect of cranberry juice deacidification on its antibacterial activity against periodontal pathogens and its anti-inflammatory properties in an oral epithelial cell model.

Cranberries are widely recognized as a functional food that can promote oral health. However, the high concentration of organic acids in cranberry juice can cause tooth enamel erosion. Electrodialysis with bipolar membrane (EDBM) is a process used for the deacidification of cranberry juice. The present study investigated whether the removal of organic acids (0%, 19%, 42%, 60%, and 79%) from cranberry juice by EDBM affects its antibacterial activity against major periodontopathogens as well as its anti-inflammatory properties in an oral epithelial cell model. A deacidification rate ≥60% attenuated the bactericidal effect against planktonic and biofilm-embedded Aggregatibacter actinomycetemcomitans but had no impact on Porphyromonas gingivalis and Fusobacterium nucleatum. Cranberry juice increased the adherence of A. actinomycetemcomitans and P. gingivalis to oral epithelial cells, but reduced the adherence of F. nucleatum by half regardless of the deacidification rate. F. nucleatum produced more hydrogen sulfide when it was exposed to deacidified cranberry juice with a deacidification rate ≥42% compared to the raw beverage. Interestingly, the removal of organic acids from cranberry juice lowered the cytotoxicity of the beverage for oral epithelial cells. Deacidification attenuated the anti-inflammatory effect of cranberry juice in an in vitro oral epithelial cell model. The secretion of IL-6 by lipopolysaccharide (LPS)-stimulated oral epithelial cells exposed to cranberry juice increased proportionally with the deacidification rate. No such effect was observed with respect to the production of IL-8. This study provided evidence that organic acids, just like phenolic compounds, might contribute to the health benefits of cranberry juice against periodontitis.

Salmon peptides limit obesity-associated metabolic disorders by modulating a gut-liver axis in vitamin D-deficient mice.

OBJECTIVE: This study investigated the effects of a low-dose salmon peptide fraction (SPF) and vitamin D3 (VitD3 ) in obese and VitD3 -deficient mice at risk of metabolic syndrome (MetS). METHODS: Obese and VitD3 -deficient low-density lipoprotein receptor (LDLr)-/- /apolipoprotein B100 (ApoB)100/100 mice were treated with high-fat high-sucrose diets, with 25% of dietary proteins replaced by SPF or a nonfish protein mix (MP). The SPF and MP groups received a VitD3 -deficient diet or a supplementation of 15,000 IU of VitD3 per kilogram of diet. Glucose homeostasis, atherosclerosis, nonalcoholic fatty liver disease, and gut health were assessed. RESULTS: VitD3 supplementation increased plasma 25-hydroxyvitamin D to optimal status whereas the VitD3 -deficient diet maintained moderate deficiency. SPF-treated groups spent more energy and accumulated less visceral fat in association with an improved adipokine profile. SPF lowered homeostatic model assessment of insulin resistance compared with MP, suggesting that SPF can improve insulin sensitivity. SPF alone blunted hepatic and colonic inflammation, whereas VitD3 supplementation attenuated ileal inflammation. These effects were associated with changes in gut microbiota such as increased Mogibacterium and Muribaculaceae. CONCLUSIONS: SPF treatment improves MetS by modulating hepatic and gut inflammation along with gut microbiota, suggesting that SPF operates through a gut-liver axis. VitD3 supplementation has limited influence on MetS in this model.

Cholecalciferol Supplementation Does Not Prevent the Development of Metabolic Syndrome or Enhance the Beneficial Effects of Omega-3 Fatty Acids in Obese Mice.

BACKGROUND: Cholecalciferol (D3) may improve inflammation, and thus provide protection from cardiometabolic diseases (CMD), although controversy remains. Omega-3 fatty acids (ω-3FA) may also prevent the development of CMD, but the combined effects of ω-3FA and D3 are not fully understood. OBJECTIVES: We determined the chronic independent and combined effects of D3 and ω-3FA on body weight, glucose homeostasis, and markers of inflammation in obese mice. METHODS: We gave 8-week-old male C57BL/6J mice, which had been fed a high-fat, high-sucrose (HF) diet (65.5% kcal fat, 19.8% kcal carbohydrate, and 14% kcal protein) for 12 weeks, either a standard D3 dose (+SD3; 1400 IU D3/kg diet) or a high D3 dose (+HD3; 15,000 IU D3/kg diet). We fed 1 +SD3 group and 1 +HD3 group with 4.36% (w/w) fish oil (+ω-3FA; 44% eicosapentaenoic acid, 25% docosahexaenoic acid), and fed the other 2 groups with corn oil [+omega-6 fatty acids (ω-6FA)]. A fifth group was fed a low-fat (LF; 15.5% kcal) diet. LF and HF+ω-6+SD3 differences were tested by a Student's t-test and HF treatment differences were tested by a 2-way ANOVA. RESULTS: D3 supplementation in the +HD3 groups did not significantly increase plasma total 25-hydroxyvitamin D and 25-hydroxyvitamin D3 [25(OH)D3] versus the +SD3 groups, but it increased 3-epi-25-hydroxyvitamin D3 levels by 3.4 ng/mL in the HF+ω-6+HD3 group and 4.0 ng/mL in the HF+ω-3+HD3 group, representing 30% and 70%, respectively, of the total 25(OH)D3 increase. Energy expenditure increased in those mice fed diets +ω-3FA, by 3.9% in the HF+ω-3+SD3 group and 7.4% in the HF+ω-3+HD3 group, but it did not translate into lower body weight. The glucose tolerance curves of the HF+ω-3+SD3 and HF+ω-3+HD3 groups were improved by 11% and 17%, respectively, as compared to the respective +ω-6FA groups. D3 supplementation, within the ω-3FA groups, altered the gut microbiota by increasing the abundance of S24-7 and Lachnospiraceae taxa compared to the standard dose, while within the ω-6FA groups, D3 supplementation did not modulate specific taxa. CONCLUSIONS: Overall, D3 supplementation does not prevent CMD or enhance the beneficial effects of ω-3FA in vitamin D-sufficient obese mice.

Towards Water, Sodium Chloride and Natural Organic Matter Recovery from Ion Exchange Spent Brine.

Despite the tremendous success of the application of anion exchange resins (IX) in natural organic matter (NOM) removal over conventional removal methods, the considerable amount of brine spent during its regeneration cycle makes its sustainability questionable. This polluting saline stream can be challenging to manage and costly to discharge. Alternatively, and with the recent shift in perception of resource recovery, the produced spent brine can no longer be seen as a polluting waste but as an unconventional source of water, minerals and nutrients. In this research, for the first time, we evaluated the effectiveness of an integrated monovalent selective electrodialysis (MSED) and direct contact membrane distillation (DCMD) system in IX spent brine desalination and resource recovery. Of particular interest were the effects of operating time on the characteristics of the monovalent permselective ion exchange membranes, the impact of the DCMD stack configuration on minimizing heat loss to the ambient environment and the efficacy of the recovered NaCl in the regenerating cycle of the exhausted IXs. Our findings demonstrated that although the recovered NaCl from the stand-alone MSED can restore nearly 60% ion exchange capacity of the exhausted IXs, coupling MSED with DCMD led to minimizing the consumption of fresh NaCl (in the IX regeneration cycle) significantly, the potential application of NOM in agriculture and diminishing the risk of the IX spent brine disposal. In addition, the initial characteristics of the ion permselective membranes were maintained after 24 h of MSED and the transmembrane flux was increased when the feed/hot compartment (in the DCMD stack) was encapsulated on two outer ends with coolant/permeate compartments as a result of less heat loss to the ambient environment.

Production of calcium- and magnesium-enriched caseins and caseinates by an ecofriendly technology.

Finding new environmentally friendly ways of producing proteins has never been of such critical public interest, both to meet consumers' needs and to preserve the environment. Milk proteins are among the most attractive protein types due to their high nutritional value and attractive functional properties. In this work, the separation of caseins by conventional chemical acidification was compared with electrodialysis with bipolar membrane coupled to an ultrafiltration module (EDBM-UF), a green process that allows the precipitation of caseins by H+ generated in situ by the bipolar membrane and, simultaneously, the production of a separated NaOH stream from OH- electrogenerated by the bipolar membrane. Caseinate production using this NaOH stream by-product and the quantity of NaOH needed to produce caseinates from both methods were also investigated. Hence, the purity and composition of caseins and caseinates were compared in terms of protein, ash, and lactose contents as well as mineral composition. The results showed for the first time that caseinates can be produced by solubilizing caseins with NaOH stream from the EDBM process. Furthermore, the caseins and caseinates produced by EDBM-UF were equivalent in terms of lactose and protein contents to their respective caseins and caseinates that were chemically produced but presented slightly lower sodium content and 3 to 4 times higher magnesium and calcium contents. The fact that calcium and magnesium are likely bound to milk caseins would ensure their favorable absorbability. These caseins or caseinates from the new EDBM-UF process could be suitable as an improved protein-based calcium or magnesium supplement, both for their enhanced nutritional quality and because they are produced by a "green" process.

Antioxidant activity and nutrient release from polyphenol-enriched cheese in a simulated gastrointestinal environment.

Green tea polyphenols are recognized for their antioxidant properties and their effects on lipid digestion kinetics. Polyphenols are sensitive to degradation in the intestinal environment. Interactions with dairy proteins could modulate the stability and biological activity of polyphenols during digestion. The objective of this study was to evaluate the release of nutrients (polyphenols, fatty acids and peptides) and the antioxidant activity in polyphenol-enriched cheese containing different levels of calcium in a simulated gastrointestinal environment. The relationship between cheese matrix texture, matrix degradation and nutrient release during digestion was also studied. Green tea extract was added to milk at 0% or 0.1%, and cheeses were produced on a laboratory scale. The level of available calcium was adjusted to low (Ca(low)), regular (Ca(reg)) or high (Ca(high)) during the salting step of the cheese-making process. Cheeses were subjected to simulated digestion. The rate and extent of fatty acid release were 21% lower for Ca(low) cheese than for Ca(reg) and Ca(high) cheeses. The greater adhesiveness of Ca(low) cheese, which resulted in lower rates of matrix degradation and proteolysis, contributed to the reduced rate of lipolysis. The presence of green tea extract in cheese reduced the release of free fatty acids at the end of digestion by 7%. The addition of green tea extract increased cheese hardness but did not influence matrix degradation or proteolysis profiles. The formation of complexes between tea polyphenols and proteins within the cheese matrix resulted in a more than twofold increase in polyphenol recovery in the intestinal phase compared with the control (tea polyphenol extract incubated with polyphenol-free cheese). Antioxidant activity was 14% higher in the digest from polyphenol-enriched cheese than in the control. These results suggest that cheese is an effective matrix for the controlled release of nutrients and for the protection of green tea polyphenol integrity and biological activity in the gastrointestinal environment.

Low-Molecular-Weight Peptides from Salmon Protein Prevent Obesity-Linked Glucose Intolerance, Inflammation, and Dyslipidemia in LDLR-/-/ApoB100/100 Mice.

BACKGROUND: We previously reported that fish proteins can alleviate metabolic syndrome (MetS) in obese animals and human subjects. OBJECTIVES: We tested whether a salmon peptide fraction (SPF) could improve MetS in mice and explored potential mechanisms of action. METHODS: ApoB(100) only, LDL receptor knockout male mice (LDLR(-/-)/ApoB(100/100)) were fed a high-fat and -sucrose (HFS) diet (25 g/kg sucrose). Two groups were fed 10 g/kg casein hydrolysate (HFS), and 1 group was additionally fed 4.35 g/kg fish oil (FO; HFS+FO). Two other groups were fed 10 g SPF/kg (HFS+SPF), and 1 group was additionally fed 4.35 g FO/kg (HFS+SPF+FO). A fifth (reference) group was fed a standard feed pellet diet. We assessed the impact of dietary treatments on glucose tolerance, adipose tissue inflammation, lipid homeostasis, and hepatic insulin signaling. The effects of SPF on glucose uptake, hepatic glucose production, and inducible nitric oxide synthase activity were further studied in vitro with the use of L6 myocytes, FAO hepatocytes, and J774 macrophages. RESULTS: Mice fed HFS+SPF or HFS+SPF+FO diets had lower body weight (protein effect, P = 0.024), feed efficiency (protein effect, P = 0.018), and liver weight (protein effect, P = 0.003) as well as lower concentrations of adipose tissue cytokines and chemokines (protein effect, P ≤ 0.003) compared with HFS and HFS+FO groups. They also had greater glucose tolerance (protein effect, P < 0.001), lower activation of the mammalian target of rapamycin complex 1/S6 kinase 1/insulin receptor substrate 1 (mTORC1/S6K1/IRS1) pathway, and increased insulin signaling in liver compared with the HFS and HFS+FO groups. The HFS+FO, HFS+SPF, and HFS+SPF+FO groups had lower plasma triglycerides (protein effect, P = 0.003; lipid effect, P = 0.002) than did the HFS group. SPF increased glucose uptake and decreased HGP and iNOS activation in vitro. CONCLUSIONS: SPF reduces obesity-linked MetS features in LDLR(-/-)/ApoB(100/100) mice. The anti-inflammatory and glucoregulatory properties of SPF were confirmed in L6 myocytes, FAO hepatocytes, and J774 macrophages.

Effect of commercial grape extracts on the cheese-making properties of milk.

Grape extracts can be added to milk to produce cheese with a high concentration of polyphenols. Four commercial extracts from whole grape, grape seed, and grape skin (2 extracts) were characterized and added to milk at concentrations of 0, 0.1, 0.2, and 0.3% (wt/vol). The effect of grape extracts on the kinetics of milk clotting, milk gel texture, and syneresis were determined, and model cheeses were produced. Whole grape and grape seed extracts contained a similar concentration of polyphenolic compounds and about twice the amount found in grape skin extracts. Radical scavenging activity was directly proportional to the phenolic compounds content. When added to milk, grape extracts increased rennet-induced clotting time and decreased the clotting rate. Although differences were observed between the extracts, the concentration added to milk was the main factor influencing clotting properties. With increasing concentrations of grape extracts, milk gels showed increased brittleness and reduced firmness. In addition, syneresis of milk gels decreased with increasing concentrations of grape extracts, which resulted in cheeses with a higher moisture content. The presence of grape extracts in milk slightly increased protein recovery in cheese but had no effect on fat recovery. With whole grape or grape seed extracts added to milk at 0.1% (wt/vol), the recovery coefficient for polyphenols was about 0.63, and decreased with increasing extract concentration in milk. Better polyphenol recovery was observed for grape seed extracts (0.87), with no concentration effect. Commercial extracts from whole grape, grape seed, or grape skin can be added to milk in the 0.1 to 0.3% (wt/vol) concentration range to produce cheese with potential health benefits, without a negative effect on cheese yield.

Deacidification of cranberry juice by electrodialysis with bipolar membranes.

Cranberry is recognized for its many benefits on human health; however, its high acidity may be a limiting factor for its consumption. This study aimed to investigate the deacidification of cranberry juice using a two simultaneous step electrodialysis with bipolar membranes (EDBM) process. In step 1 (deacidification), during the 6 h treatment, the pH of the juice increased from 2.47 to 2.71 and a deacidification rate of 22.84% was obtained, whereas in step 2 (pH lowering) the pH of juice 2 was almost stable. Citric, quinic, and malic acid were extracted with a maximum of 25% and were mainly transferred to the KCl 2 fraction. A significant loss of anthocyanins in juice 2 (step 2) was observed, due to their oxidation by oxygen incorporated by the centrifugal pump. This also affected its coloration. The first step of the EDBM process was successful for cranberry juice deacidification and could be improved by increasing the number of membranes stacked.

Interaction of green tea polyphenols with dairy matrices in a simulated gastrointestinal environment.

The consumption of polyphenols in green tea has been associated with beneficial health effects. Although polyphenols are unstable in the intestinal environment, they may be protected by interactions with dairy proteins during digestion. The objectives of this study were to evaluate the effect of a green tea extract on the digestibility of different dairy matrices and to monitor the antioxidant activity of these matrices with or without the green tea extract during digestion in a simulated gastrointestinal environment. Milk, yogurt and cheese with similar fat-to-protein ratios were subjected to simulated digestion. Matrix degradation, protein and fat hydrolysis, polyphenol concentration and radical scavenging activity were analyzed during gastric and intestinal digestion phases. Cheese was the matrix most resistant to protein and fat digestion. The addition of the green tea extract significantly decreased proteolysis in the gastric phase but had no effect in the intestinal phase. The kinetics of fatty acid release was reduced by the presence of the green tea extract. Transition from the gastric phase to the intestinal phase induced a 50% decrease in the antioxidant activity of the control (tea extract dispersed in water) due to the degradation of polyphenols. The presence of dairy matrices significantly improved polyphenol stability in the intestinal phase and increased the antioxidant activity by 29% (cheese) to 42% (milk) compared to the control. These results suggest that simultaneous consumption of green tea and dairy products helps to maintain the integrity and antioxidant activity of polyphenols during digestion.

Rapid HPLC-MS method for the simultaneous determination of tea catechins and folates.

An effective and rapid HPLC-MS method for the simultaneous separation of the eight most abundant tea catechins, gallic acid, and caffeine was developed. These compounds were rapidly separated within 9 min by a linear gradient elution using a Zorbax SB-C18 packed with sub 2 µm particles. This methodology did not require preparative and semipreparative HPLC steps. In fact, diluted tea samples can be easily analyzed using HPLC-MS as described in this study. The use of mass spectrometry detection for quantification of catechins ensured a higher specificity of the method. The percent relative standard deviation was generally lower than 4 and 7% for most of the compounds tested in tea drinks and tea extracts, respectively. Furthermore, the method provided excellent resolution for folate determination alone or in combination with catechins. To date, no HPLC method able to discriminate catechins and folates in a quick analysis has been reported in the literature.

Promising results of cranberry in the prevention of oral Candida biofilms.

In the context of dental caries prevention by natural foodstuff sources, antifungal and antibiofilm activities of dry commercial extracts of cranberry fruit (Vaccinium macrocarpon Aiton) and two other red fruits (Vaccinium myrtillus L. and Malpighia punicifolia L.) were assessed on Candida albicans and Candida glabrata yeasts. When added to the culture medium, the cranberry extract displayed a significant anti-adhesion activity against Candida spp. when used at low concentrations. In addition, the pretreatment of surfaces with this extract induced an anti-adhesion activity mainly against C. glabrata yeasts and an antibiofilm activity against C. albicans. This activity was dependent on concentration, species, and strain. A phytochemical investigation bioguided by anti-adhesion tests against the two Candida species was carried out on crude cranberry juice to determine the active fractions. Three subfractions enriched in proanthocyanidins showed an anti-adhesion activity at low concentrations. This study investigated for the first time the interest of crude extracts of cranberry and cranberry juice fractions to prevent biofilms of C. glabrata. It highlighted the potency of consuming this fruit and using it as a source of anti-adhesion agents.

A two-stage, single-arm, phase II study of EGCG-enriched green tea drink as a maintenance therapy in women with advanced stage ovarian cancer.

OBJECTIVES: A two-stage, single-arm, phase II study was conducted to assess the effectiveness and safety of an epigallocatechin gallate (EGCG)-enriched tea drink, the double-brewed green tea (DBGT), as a maintenance treatment in women with advanced stage serous or endometrioid ovarian cancer (clinicaltrials.gov, NCT00721890). METHODS: Eligible women had FIGO stage III-IV serous or endometrioid ovarian cancer. They had to undergo complete response after debulking surgery followed by 6 to 8 cycles of platinum/taxane chemotherapy at the Centre Hospitalier Universitaire de Québec. They all had to drink the DBGT, 500 mL daily until recurrence or during a follow-up of 18 months. The primary endpoint was the absence of recurrence at 18 months. Statistical analyses were done according to the principle of intention to treat. Using a two-stage design, the first stage consisted of 16 enrolled patients. At the end of the follow-up, if 7 or fewer patients were free of recurrence, the trial stopped. Otherwise, accrual would continue to a total of 46 patients. RESULTS: During the first stage of the study, only 5 of the 16 women remained free of recurrence 18 months after complete response. Accordingly, the clinical trial was terminated. Women's adherence to DBGT was high (median daily intake during intervention, 98.1%, interquartile range: 89.7-100%), but 6 women discontinued the intervention before the end of their follow-up. No severe toxicity was reported. CONCLUSIONS: DBGT supplementation does not appear to be a promising maintenance intervention in women with advanced stage ovarian cancer after standard treatment.

Redox properties of catechins and enriched green tea extracts effectively preserve L-5-methyltetrahydrofolate: assessment using cyclic voltammetry analysis.

A cyclic voltammetry (CV) study was performed in pH 5.5 Britton-Robinson buffer at room temperature to study the stability of 1mM l-5-methyltetrahydrofolate (l-5-MTHF) in combination with epigallocatechin-gallate-enriched extract (EGCGe) and epigallocatechin-enriched extract (EGCe). The combination of l-5-MTHF with enriched catechin extracts provided enhanced stability of l-5-MTHF over a period of 12h under ambient air conditions at pH 5.5. CV experiments showed that increasing the concentrations of EGCGe or EGCe extracts from 80 to 400mg/L produced a decrease in the second oxidation peak of l-5-MTHF. Thus, we calculated that l-5-MTHF remained at nearly 90% when in the presence of enriched tea extracts, compared to 74% without the tea antioxidants. The catechins responsible for this preservation were EGCG and C, confirmed by LC-MS. Compared to covalent link only low interaction (hydrogen bonds) between the different catechins present in the tea extract would stabilise l-5-MTHF. Rather, it was hypothesised that EGCGe and EGCe were effective agents to preserve l-5-MTHF, through a mechanism that also involved the redox potential of catechins to maintain l-5-MTHF in its reduced form.

Separation of bioactive peptides by membrane processes: technologies and devices.

Although many patents reported bioactive peptides with numerous demonstrated bioactivities and potential applications, there exist some limitations to the production of large quantities to satisfy the growing market demands. Indeed, considering that most functional peptides are present in complex matrices containing a large number of hydrolyzed protein fractions, their separation and purification are required. Some advances have been made in the use of conventional pressure-driven processes for the continuous production and separation of peptides, however, most of these patented technologies are not scalable and demonstrate a low selectivity when separating similar sized biomolecules. To improve the separation efficiency, the use of an external electric field during pressure-driven filtration was proposed and patented. However, whatever the claims, the pressure gradient brings about the accumulation of peptides at the nearby membrane surface and affects the membrane transport selectivity. To overcome these drawbacks, a recent patent proposed the simultaneous fractionation of acidic and basic peptides, using a conventional electrodialysis cell, in which some ion exchange membranes are replaced by ultrafiltration ones. The perspectives in the field of peptide separation will be the development of new membrane materials and new equipments such as microfluidic devices to improve selectivity and yield of production.

Green tea for ovarian cancer prevention and treatment: a systematic review of the in vitro, in vivo and epidemiological studies.

OBJECTIVE: This systematic review was conducted to examine the effects of green tea or green tea components on the prevention and progression of epithelial ovarian cancer. METHODS: Using Medline, EMBASE and SciVerse (last researched: July 2011), we retrieved 22 articles including 5 epidemiological studies. RESULTS: In epithelial ovarian cancer cell lines, green tea and green tea components have been shown to downregulate the expression of proteins involved in inflammation, cell signalization, cell motility and angiogenesis. Green tea and green tea components would induce apoptosis and could potentiate the effects of cisplatin, a chemotherapeutic agent. In human observational studies, significant associations between green tea intake and both decreased ovarian cancer occurrence and better prognosis were reported. CONCLUSIONS: Available literature suggests potential molecular targets for green tea in ovarian cancer treatment and also provides data supporting the clinical evaluation of the role of green tea or green tea components in ovarian cancer prevention and treatment.

Thermal oxidation studies on reduced folate, L-5-methyltetrahydrofolic acid (L-5-MTHF) and strategies for stabilization using food matrices.

The thermal stability of L-5-methyltetrafolic acid (L-5-MTHF) was investigated in model/buffer systems and food systems. L-5-MTHF degradation followed first-order reaction kinetics with relatively greater (P < 0.01) stability at pH 4 compared to pH 6.8 in the buffer systems. This was confirmed using cyclic voltammetry. The stability (for example, k-values) of L-5-MTHF in an oxygen controlled environment improved (P < 0.001) proportionally when in the presence of increasing molar ratios of sodium ascorbate (NaAsc). The addition of NaAsc to L-5-MTHF after heat treatment was also effective at returning thermally oxidized L-5-MTHF back to its original form. A scheme was developed to explain the degradation and regeneration of L-5-MTHF. The importance of antioxidant protection of L-5-MTHF from thermal oxidation was extended using 2 distinct food systems; namely skim milk and soy milk, both with known antioxidant capacities. We conclude that the antioxidant activity of food components can enhance the stability of L-5-MTHF.