José Ángel Rufián-Henares

Antioxidant capacity, total phenols and color profile during the storage of selected plants used for infusion.

Many plants, like tea, are widely used for preparing herbal infusions. These plants have an interesting antioxidant capacity that may change after harvesting depending on the technological processing and the storage conditions. We determined the antioxidant capacity (ABTS, DPPH and FRAP methods), total phenolic content and color analysis (reflectance) of 36 plants traditionally consumed in Spain as infusion. Green tea was the most antioxidant herb, although oregano and lemon balm showed also a very high antioxidant capacity, as well as phenolic content. The antioxidant study after 3-month storage at different temperatures showed that up to a 50% of the total antioxidant capacity could be lost. Color analysis correlated with antioxidant capacity evolution, being a quick tool to control the storage conditions. Finally, our data confirm that the intake of one serving of plant infusion could release the equivalent of up to 1,500 μmol trolox, being a good source of antioxidants for the human diet.

Relationship between HMF intake and SMF formation in vivo: an animal and human study

Scope: 5‐Hydroxymethylfurfural (HMF) is a furanic compound produced in heat‐processed foods by nonenzymatic browning reactions. HMF has been demonstrated to be hepato‐ and nephrotoxic in animals with a link to its metabolite 5‐sulfooxymethylfurfural (SMF). To date little is known about either the formation of SMF from ingested HMF or the formation of DNA adducts in animals or human beings. Methods and results: To assess SMF in vivo formation, we first performed a study in mice treated with high/low doses of oral HMF. We found increased concentrations of SMF in plasma and DNA SMF‐adducts in leukocytes, hepatic tissue, and kidneys by means of LC–MS/MS, but no spatial formation in such tissues was observed by MALDI‐MS imaging technology due to low sensitivity. In a second experiment, we measured the exposure to HMF in a Spanish preadolescent population. We analyzed the concentration of HMF metabolites (plasma, urine) and measured, for the first time, the presence of SMF in plasma and DNA SMF‐adducts in leukocytes. Conclusion: This study provides the first evidence that oral HMF is readily transformed into SMF in vivo, giving rise to the formation of DNA adducts in a direct relation with HMF intake, both in animals and human beings.

Evolution of Fatty Acid Profile and Lipid Oxidation During Enteral Formula Storage

BACKGROUND Enteral formulas can be stored for up to 2 years. Fat oxidation during storage can lead to the loss of nutritive value and generation of toxic products such as lipid peroxides. METHODS Two standard enteral formulas were stored for short periods at high temperatures (1-4 weeks at 32-55°C) or for long periods at low temperatures (12-36 weeks at 4°C, 20°C, or 30°C). The present study included the assessment of lipid oxidation by measuring related fluorescent compounds and the evolution of fatty acids profile. RESULTS Enteral formula fat was oxidized under all assayed conditions, including storage at 4°C. The loss of essential fatty acids (linoleic and linolenic acids) was always higher when time and temperature were increased. The ω6/ω3 ratio was increased by storage from 5.6 to 7.8, which could exacerbate the inflammatory response in critically ill patients. Fluorescence intensity increased with time and temperature of storage and was correlated with the decrease in essential fatty acids (lineal correlation between -0.9416 and -0.9996). CONCLUSIONS Enteral formula fat was oxidized during storage, leading to a loss of nutritional value. These formulas should be stored under refrigeration to minimize this loss. Finally, fluorescence measurement proved to be a fast and easy method to assess fat oxidation status.

Antioxidant balance after long-term consumption of standard diets including bread crust glycated compounds by adult rats

The objective of the present study was to evaluate the in vivo uptake of antioxidant capacity (AC) in rats fed on diets containing commonly consumed MRPs obtained from bread crust (BC) at long-term. Additionally we focused on understanding the effects of those compounds on the oxidative status of these animals. The global antioxidant response of the diets was measured. During 88 days, rats were fed control diet or diets containing BC or its soluble high molecular weight, soluble low molecular weight or insoluble fractions (BC, HMW, LMW and insoluble diets, respectively). In the final week, faeces from different dietary treatments were collected to determine the AC still retained in it and then calculate the uptake efficiency of AC. Animals were sacrificed and the liver and biceps brachii muscle were removed to investigate catalase (CAT), superoxide dismutase (SOD), glutathione peroxidase (GPx) and reduced glutathione (GSH) levels. The addition of BC or its derivatives in the diet led to a significantly higher AC excreted with the faeces and to a lower uptake rate (around 90% in these groups vs. 98% in the control group). The muscle and liver showed different oxidative status after consumption of experimental diets. The muscle evidenced certain oxidative damage due to the BC consumption, more pronounced when the isolated fractions were ingested. However, the BC diet, but not the rest, induced a positive effect on the antioxidant defence in the liver, the key organ for xenobiotic metabolism, with increases in the CAT and GPx activities as well as the GSH stock (56, 20 and 14% with respect to the control group, respectively). The discordance found between the antioxidant status of muscle and antioxidant status of liver highlights the importance of considering several tissues to establish the effect of glycated compounds on the redox balance in an organism.

Modifications in bacterial groups and short chain fatty acid production in the gut of healthy adult rats after long-term consumption of dietary Maillard reaction products

Bread crust (BC) is one of the major sources of Maillard reaction products (MRPs) in the Western diet. This work was designed to analyze the impact of diets containing important levels of MRPs from BC on intestinal bacterial growth and short chain fatty acids (SCFAs) production in adult rats. Additionally, the pools of compounds excreted in feces attending to their molecular weights were analyzed. Rats were fed for 88days a control diet or diets containing BC or its soluble high molecular weight (HMW), soluble low molecular weight (LMW) or insoluble fractions, respectively. Intestinal (cecum) microbiota composition was determined by qPCR analysis. Consumption of the BC diet lowered (P<0.05) Lactobacillus spp. and Bifidobacterium spp. log10 counts (8 and 14%, respectively), an effect for which soluble LMW and HMW fractions of BC seemed to be responsible. In these same animals, Escherichia/Shigella counts increased by around 45% (P<0.05), a fact which correlated with a higher production of formic acid in feces (r=0.8197, P=0.0458), and likely caused by the combined consumption of all MRPs contained in the BC. A significant 5-fold increment (P<0.05) was detected in the fecal proportion of propionic acid in the BC group, one of the products that have largely been associated with anti-inflammatory actions. Regarding the distribution of MRPs in feces, only the LMW fed group exhibited a predominance of those ranging between 90,000-1000Da, whereas the rest of the groups presented higher amounts of products above 90,000Da. It is concluded that dietary Maillard reaction products are in vivo fermented by the gut microbiota, thereby changing both the pattern of SCFAs production and the microbiota composition.

Effects of long-term consumption of standard diets including glucose-lysine model glycated compounds on the antioxidant status of adult rats

Our purpose was to evaluate the uptake of antioxidant capacity (AC) in rats fed long-term a diet containing commonly consumed Maillard reaction products (MRPs) from the glucose-lysine system. The effects on the oxidative status of liver, biceps brachii muscle and serum were also tested. The presence of model MRPs in the diet, especially melanoidins, led to a significantly higher intake (24.0μmolTrolox/day), faecal excretion (0.604μmolTrolox/day), and uptake (23.4μmolTrolox/day) of AC, although the uptake rate remained stable compared to the control group (97.5%). Consumption of the assayed MRPs did not affect the hepatic antioxidant defence while some positive modifications, like an increase in glutathione peroxidase, were detected in muscle (29%) and serum (400%). This pointed to an improved antioxidant capacity. Despite the interesting findings for these specific MRPs, attention must be paid to the overall consumption of MRPs from different sources in a conventional diet, due to their implications in the development/advance of many disorders.

Does the pelleting process affect the nutritive value of a pre-starter diet for suckling piglets? Ex vivo studies on mineral absorption†

BACKGROUND The effects of pelleting on the extent of the Maillard reaction (MR) and on calcium, magnesium and zinc solubility and absorption were analysed in a conventional pre-starter diet for suckling piglets. Development was tested measuring colour, absorbance (280/420 nm), fluorescence, residual free lysine, furosine, hydroxymethylfurfural (HMF) and furfural contents before and after pelleting. Fluorescence, absorbance and mineral solubility were also measured after in vitro digestion of diets. The effects on mineral absorption were tested using Caco-2 cells. RESULTS MR indexes confirmed the development of the reaction during the pelleting of this particular diet compared with the meal diet. The CIE-Lab colour parameters showed a decrease in luminosity (L*) and progress of the colour to the red zone (a*) in the pelleted diet. A 36% decrease in free lysine content was observed. Significant correlations were observed between fluorescence intensity and furosine levels, HMF and furfural. The pelleting process did not modify calcium and magnesium solubility after in vitro digestion, but soluble zinc increased. The efficiency of calcium and zinc transport across Caco-2 cell monolayers was greater in the pelleted diet. CONCLUSIONS Evidence of MR development is shown, resulting in various nutritional consequences. Optimisation of pelleting could result in a better formulation of diets for feedstuffs.

Ulcerative Colitis and Crohn’s Disease Are Associated with Decreased Serum Selenium Concentrations and Increased Cardiovascular Risk

The incidence of inflammatory bowel disease (IBD) and associated oxidative stress is increasing. The antioxidant mineral selenium (Se) was measured in serum samples from 106 IBD patients (53 with ulcerative colitis (UC) and 53 with Crohn’s disease (CD)) and from 30 healthy controls. Serum Se concentrations were significantly lower in UC and CD patients than in healthy controls (p < 0.001) and significantly lower in CD patients than in UC patients (p = 0.006). Se concentrations in patients were significantly influenced by sex, body mass index (BMI), the inflammatory biomarker α-1-antitrypsin, surgery, medical treatment, the severity, extent, and form of the disease and the length of time since onset (p < 0.05). Se concentrations in IBD patients were positively and linearly correlated with nutritional (protein, albumin, prealbumin, cholinesterase and total cholesterol) and iron status-related (hemoglobin, Fe and hematocrit) parameters (p < 0.05). A greater impairment of serum Se and cardiovascular status was observed in CD than in UC patients. An adequate nutritional Se status is important in IBD patients to minimize the cardiovascular risk associated with increased inflammation biomarkers, especially in undernourished CD patients, and is also related to an improved nutritional and body iron status.

Evolution of the Maillard Reaction in Glutamine or Arginine-Dextrinomaltose Model Systems

Enteral formulas are foods designed for medical uses to feed patients who are unable to eat normally. They are prepared by mixing proteins, amino acids, carbohydrates and fats and submitted to sterilization. During thermal treatment, the Maillard reaction takes place through the reaction of animo acids with reducing sugars. Thus, although glutamine and arginine are usually added to improve the nutritional value of enteral formulas, their final concentration may vary. Thus, in the present paper the early, intermediate, and advanced states of the Maillard reaction were studied in model systems by measuring loss of free amino acids through the decrease of fluorescence intensity with o-phtaldialdehyde (OPA), 5-Hydroximethylfurfural (HMF), furfural, glucosylisomaltol, fluorescence, and absorbance at 420 nm. The systems were prepared by mixing glutamine or arginine with dextrinomaltose (similar ingredients to those used in special enteral formula), and heated at 100 °C, 120 °C and 140 °C for 0 to 30 min. The recorded changes in the concentration of furanic compounds was only useful for longer heating times of high temperatures, while absorbance and fluorescence measurements were useful in all the assayed conditions. In addition, easiness and sensitivity of absorbance and fluorescence make them useful techniques that could be implemented as indicators for monitoring the manufacture of special enteral formulas. Glucosylisomaltol is a useful indicator to monitor the manufacture of glutamine-enriched enteral formulas.

Relationship between Glycation and Polyphenol Content and the Bioactivity of Selected Commercial Soy Milks

Soy milk is a health-promoting beverage of which consumption is steadily expanding. Different bioactivities have been associated with soy products such as antioxidant capacity, anti-inflammatory properties, or decrease of cancer development risk. These activities have been related to the presence of several compounds, including polyphenols and serine protease inhibitors, although factors influencing such activities have been scarcely studied. In this study, we have determined the antioxidant capacity (ABTS and FRAP methods measured with the global antioxidant response, GAR protocol), total phenolic content, serine protease inhibitory activity, and presence of heat damage indicators in commercial soy milks. Polyphenols were primarily responsible for the antioxidant capacity of soy milks, increasing their concentration after digestion. Glycation under heat treatment might be responsible for decreasing protease inhibitory activities in soy milks. The results obtained support a role for furosine, a known marker of Maillard reaction and glycation, as a potential indicator to monitor both thermal treatment and effects on protease inhibitory activities in soy milk. The contribution of soy milk consumption to the daily intake of antioxidants and serine protease inhibitory activities is discussed.