Jaime Amaya-Farfan

Rnai-mediated silencing of the myo-inositol-1-phosphate synthase gene (GmMIPS1) in transgenic soybean inhibited seed development and reduced phytate content

Inositol plays a role in membrane trafficking and signaling in addition to regulating cellular metabolism and controlling growth. In plants, the myo-inositol-1-phosphate is synthesized from glucose 6-phosphate in a reaction catalyzed by the enzyme myo-inositol-1-phosphate synthase (EC 5.5.1.4). Inositol can be converted into phytic acid (phytate), the most abundant form of phosphate in seeds. The path to phytate has been suggested to proceed via the sequential phosphorylation of inositol phosphates, and/or in part via phosphatidylinositol phosphate. Soybean [Glycine max (L.) Merrill] lines were produced using interfering RNA (RNAi) construct in order to silence the myo-inositol-1-phosphate (GmMIPS1) gene. We have observed an absence of seed development in lines in which the presence of GmMIPS1 transcripts was not detected. In addition, a drastic reduction of phytate (InsP6) content was achieved in transgenic lines (up to 94.5%). Our results demonstrated an important correlation between GmMIPS1 gene expression and seed development.

State of Knowledge on Amaranth Grain: A Comprehensive Review

Amaranth grain is a highly nutritional pseudocereal with a superior amount of proteins when compared to true cereals. It is a reasonably well-balanced food with functional properties that have been shown to provide medicinal benefits. The health benefits attributed include decreasing plasma cholesterol levels, stimulating the immune system, exerting an antitumor activity, reducing blood glucose levels and improving conditions of hypertension and anemia. In addition, it has been reported to possess anti-allergic and antioxidant activities. The present article provides a comprehensive overview of amaranth grain that focuses on recent research reporting its use in the clinical practice and its possible benefits to human health.

Probiotic yogurts manufactured with increased glucose oxidase levels: Postacidification, proteolytic patterns, survival of probiotic microorganisms, production of organic acid and aroma compounds

We investigated the effect of increased glucose oxidase concentration as a technological option to decrease oxidative stress during the processing of probiotic yogurts. Probiotic yogurts were produced with increased concentrations of glucose oxidase (0, 250, 500, 750, or 1,000 mg/kg) and submitted to physicochemical and microbiological analysis at 1, 15, and 30 d of refrigerated storage. Higher concentrations of glucose oxidase (750 and 1,000 mg/kg) and a longer storage time were found to have an influence on the characteristics of the probiotic yogurt, contributing to more extensive postacidification, an increase in the dissolved oxygen level, and higher proteolysis. In addition, increased production of aroma compounds (diacetyl and acetaldehyde) and organic acids (mainly lactic acid) and a decrease in the probiotic bacteria count were reported. The use of glucose oxidase was a feasible option to minimize oxidative stress in probiotic yogurts. However, supplementation with excessive amounts of the enzyme may be ineffective, because insufficient substrate (glucose) is present for its action. Consumer tests should be performed to evaluate changes in the sensory attributes of the probiotic yogurts with increased supplementation of glucose oxidase. In addition, packaging systems with different permeability to oxygen should be evaluated.

Performance of quinoa (Chenopodium quinoa Willd) flour in the manufacture of gluten-free spaghetti

The objective of this work was to assess the performance of mixtures of corn and quinoa (Chenopodium quinoa Willd) flours in the development of a spaghetti-type product. Cooking quality (loss of solids, volume increase, weight increase), texture (adhesiveness, elasticity), peak and final viscosities and moisture content of the pre-gelatinised flour mixtures were the physical parameters studied. The mean values for loss of solids, weight increase, volume increase, adhesiveness and moisture were 162 g kg−1, 2.3 times, 2.6 times, 2090.7 g and 384 g kg−1 respectively. Peak viscosity and elasticity provided information relevant, yet not definitive, to both formulation and processing of the product. However, the model developed was predictive for final viscosity. The combination of independent variables that resulted in higher elasticity values, desirable for spaghetti, were short thermal treatment and low-to-medium quinoa additions. All peak viscosities were low with respect to the untreated flour. For final viscosity, however, the best combinations were short heat treatments across the entire range of quinoa contents. Sensory acceptability testing of the spaghetti by a consumer panel was also included. © 2000 Society of Chemical Industry

Effect of the inoculation level of Lactobacillus acidophilus in probiotic cheese on the physicochemical features and sensory performance compared with commercial cheeses.

The complex metabolism of probiotic bacteria requires several technological options to guarantee the functionally of probiotic dairy foods during the shelf life. This research aimed to evaluate the effect of the supplementation of increasing amounts of Lactobacillus acidophilus (0, 0.4, or 0.8 g/L of milk) on the physicochemical parameters and sensory acceptance of Minas fresh cheese. In addition, the sensory acceptance of probiotic cheeses was assessed using a consumer test and compared with commercial cheeses (conventional and probiotic). High counts (9.11 to 9.42 log cfu/g) of L. acidophilus were observed throughout the shelf life, which contributed to the maintenance of its probiotic status and resulted in lower pH values and greater production of organic acids. The probiotic cheeses presented lower scores for appearance, aroma, and texture compared with conventional cheeses. Internal preference mapping explained almost 60% of the total variation of the data and showed a large number of consumers concentrated near the conventional cheeses, demonstrating greater preference for these samples. The findings indicated that some negative sensory effects could occur when high level of supplementation with L. acidophilus is used in probiotic cheese processing.

Dietary reference intakes: aplicabilidade das tabelas em estudos nutricionais

Diet planning and food intake evaluation are professional activities classically performed by comparing mean values of ingestion against reference values of nutrient and energy intakes, for either groups or individuals. Without considering certain intrinsic limitations of the reference values, such task may render equivocal conclusions with regard to nutritional adequacy. The nutritional recommendations, prepared as a joint effort between the US Institute of Medicine and Health Canada published since 1997 and known as Dietary Reference Intakes, offer a new model by establishing indices of nutrient intake and refining the concept of risk associated with diet evaluation. Errors of both intra and interindividual nature, due to the variability of an individuals feeding pattern, the uneven distribution of requirements within a population, respectively, and the small number of days of observation, are factors that together can have a large impact on the confidence of the analysis. For these reasons, only the judicious selection of the reference values, published in the form of tables from 1997 through 2005, should enable the user to reach the proper assessment. This paper had the objective of highlighting various critical characteristics of application and compiling the values in order to facilitate their use by both professionals and students of the area.Diet planning and food intake evaluation are professional activities classically performed by comparing mean values of ingestion against reference values of nutrient and energy intakes, for either groups or individuals. Without considering certain intrinsic limitations of the reference values, such task may render equivocal conclusions with regard to nutritional adequacy. The nutritional recommendations, prepared as a joint effort between the US Institute of Medicine and Health Canada published since 1997 and known as Dietary Reference Intakes, offer a new model by establishing indices of nutrient intake and refining the concept of risk associated with diet evaluation. Errors of both intra and interindividual nature, due to the variability of an individuals feeding pattern, the uneven distribution of requirements within a population, respectively, and the small number of days of observation, are factors that together can have a large impact on the confidence of the analysis. For these reasons, only the judicious selection of the reference values, published in the form of tables from 1997 through 2005, should enable the user to reach the proper assessment. This paper had the objective of highlighting various critical characteristics of application and compiling the values in order to facilitate their use by both professionals and students of the area.

Hypertension parameters are attenuated by the continuous consumption of probiotic Minas cheese

The aim of this study was to investigate the effects of ingestion of probiotic Minas Frescal cheese (PMFC) on hypertension parameters in spontaneously hypertensive rats (SHRs). Twenty-eight animals were divided into four groups fed with different experimental diets: control initial (CI), control final (CF), traditional Minas Frescal cheese (CMFC), and PMFC. The latter two groups were fed with 20g of cheese per day for 15days. All groups were assessed for blood pressure and health parameters. The results show that the group fed with PMFC exhibited significantly lower blood pressure when compared to the group fed with CMFC, CI, and CF. Regarding the other health parameters, an improvement in blood lipids (triglycerides and cholesterol) was observed for the group fed with PMFC as compared with CMFC. No significant differences were observed in renal function parameters. Our findings suggest that consumption of probiotic cheese can be potentially useful to improve the cardiovascular health parameters.

Probiotic cheese attenuates exercise-induced immune suppression in Wistar rats.

Intense physical activity results in a substantial volume of stress and hence a significant probability of immunosuppression in athletes, with milk proteins being, perhaps, the most recommended protein supplements. Consumption of a probiotic cheese can attenuate immune suppression induced by exhausting exercise in rats. A popular Brazilian fresh cheese (Minas Frescal cheese) containing Lactobacillus acidophilus LA14 and Bifidobacterium longum BL05 was fed for 2wk to adult Wistar rats, which then were brought to exhaustion on the treadmill. Two hours after exhaustion, the rats were killed and material was collected for the determination of serum uric acid, total and high-density lipoprotein cholesterol fraction, total protein, triacylglycerols, aspartate aminotransferase, alanine aminotransferase, creatine kinase, and blood cell (monocyte, lymphocyte, neutrophil, and leukocyte) counts. Exercise was efficient in reducing lymphocyte counts, irrespective of the type of ingested cheese, but the decrease in the group fed the probiotic cheese was 22% compared with 48% in the animals fed regular cheese. Monocyte counts were unaltered in the rats fed probiotic cheese compared with a significant decrease in the rats fed the regular cheese. Most importantly, ingestion of the probiotic cheese resulted in a >100% increase in serum high-density lipoprotein cholesterol and a 50% decrease in triacylglycerols. We conclude that probiotic Minas Frescal cheese may be a viable alternative to enhance the immune system and could be used to prevent infections, particularly those related to the physical overexertion of athletes.

Carbohydrate-energy restriction may protect the rat brain against oxidative damage and improve physical performance.

Chronic energy restriction, alpha-tocopherol supplementation and their interaction with exhaustive exercise were investigated. Eleven-week-old male Wistar rats (n 6x 10) were fed either a control (C), a 30 % carbohydrate-energy-restricted control (R) or an alpha-tocopherol-supplemented (S) diet for 5 months. The animals in each diet were divided into exercised (E) and non-exercised (NE) groups. Before killing, the exercised rats were required to run to exhaustion (39 (se 6), 69 (se 11) and 18 (se 2) min for the C, R and S groups, respectively). Lipid peroxidation (thiobarbituric acid-reactive substances; TBARS), protein damage (reactive carbonyls) and alpha-tocopherol were determined in gastrocnemius, liver, brain and/or plasma. There was no difference in lipid peroxidation between the R and C groups, but in liver and muscle peroxidation appeared significantly lower in the S than the other two diets. TBARS in the brain were similar in all groups. On the other hand, reactive carbonyls showed that both the R and S diets reduced protein damage in the brain, while exhaustive exercise increased it. For liver and muscle, however, reactive carbonyl levels were similar in all groups. alpha-Tocopherol supplementation increased the vitamin concentrations in liver, muscle and plasma, but exercise decreased them in plasma and brain. Carbohydrate-energy restriction increased (P=0.0025) resistance to exhaustive exercise considerably without depleting stores of alpha-tocopherol or exacerbating oxidative damage in monitored tissues. It is concluded that while exhaustive exercise promotes a tissue-specific oxidative damage detectable only in brain proteins, both experimental diets tended to ameliorate this condition.

Prevalência de hipovitaminose a em crianças da periferia do município de Campinas, São Paulo, Brasil

The prevalence of hypovitaminosis A among children of the peripheral districts of the city of Campinas, S o Paulo, Brazil, was estimated by determining serum retinol levels by High Performance Liquid Chromatography (HPLC) in a sample of 131 children aged between three and ten years, between April 1991 and February 1992. A prevalence of 17.6% and retinol concentrations in the range of 0.35 to 0.70 micromol/L were found (CI=11.1-24.1; 95%), indicating the existence of public health risk Ophthalmological examinations, however, failed to detect any cases of xerophthalmy. Additional characterization of the sample was obtained from 341 children. The per capita income of the average household was surprisingly high for low-income areas. According to FAO-WHO standards, food consumption was adequate only for protein (133.96%). Adequacy levels were low for energy (87.76%) and particularly for vitamin A (66.13%) and iron (42.14%). Height for-age and weight-for-height anthropometric indices revealed that many children were located below -1 standard deviation.