Jorge Jiménez-Castro

Oral fat perception is related with body mass index, preference and consumption of high-fat foods

Oral sensory perception may play an important role in food preferences, driving food intake and energy balance. Fat perceived in oral cavity has been associated with satiety and homeostatic signals. The purpose of this study was to test the hypothesis that fat oral-intensity perception may be associated with BMI, food preferences and consumption of fat-rich foods. The ability to perceive linoleic acid at different concentrations by intensity scaling was measured in young adults (n=121), characterized by anthropometric measurements such as body mass index (BMI), waist circumference (WC) and total body fat (TBF) percentage. Additionally, dietary habits were recorded online during 35days using a questionnaire designed according to the 24-hour recall and the food diary methods. Finally, food preferences were evaluated online using a nine-point hedonic scale. Taste sensitivity (intensity scaling with suprathreshold concentrations) was estimated with different linoleic acid concentrations using a linear scale of 150mm labeled at the ends. Four groups were established after the ratings for oral-intensity perception of linoleic acid: quartile high ratings (QH), quartile medium-high ratings (QMH), quartile medium-low ratings (QML) and quartile low ratings (QL). Participants with high-intensity ratings for linoleic acid (QH) had lower BMI (p=0.04) and waist circumference (WC) (p=0.03) values than participants in the QL group. High-fat foods (foods with more than 20% of energy from lipids such as fast foods and Mexican street foods) were less preferred by participants with high-intensity ratings for linoleic acid (QH) than by participants with medium- (QMH, QML) and low-(QL) intensity ratings (p<0.01). Also, participants with high-intensity ratings for linoleic acid (QH) presented lower consumption of high-fat foods like fast foods (p=0.04) and Mexican street foods (p=0.03) than subjects with medium- (QMH, QML) and low-(QL) intensity ratings. Overall, these data suggest that the participants intensity ratings for oral perception of linoleic acid were inversely correlated with BMI, WC, preference and consumption of high-fat foods such as fast foods and Mexican street foods, and it may serve as a predisposing factor for fat consumption in humans.

Contamination of the Conchos River in Mexico: does it pose a health risk to local residents?

Presently, water contamination issues are of great concern worldwide. Mexico has not escaped this environmental problem, which negatively affects aquifers, water bodies and biodiversity; but most of all, public health. The objective was to determine the level of water contamination in six tributaries of the Conchos River and to relate their levels to human health risks. Bimonthly samples were obtained from each location during 2005 and 2006. Physical-chemical variables (temperature, pH, electrical conductivity (EC), Total solids and total nitrogen) as well as heavy metals (As, Cr, Cu, Fe, Mn, Ni, V, Zn, and Li) were determined. The statistical analysis considered yearly, monthly, and location effects, and their interactions. Temperatures differed only as a function of the sampling month (P < 0.001) and the pH was different for years (P = 0.006), months (P < 0.001) and the interaction years x months (P = 0.018). The EC was different for each location (P < 0.001), total solids did not change and total nitrogen was different for years (P < 0.001), months (P < 0.001) and the interaction years x months (P < 0.001). The As concentration was different for months (P = 0.008) and the highest concentration was detected in February samples with 0.11 mg L−1. The Cr was different for months (P < 0.001) and the interaction years x months (P < 0.001), noting the highest value of 0.25 mg L−1. The Cu, Fe, Mn, Va and Zn were different for years, months, and their interaction. The highest value of Cu was 2.50 mg L−1; for Fe, it was 16.36 mg L−1; for Mn it was 1.66 mg L−1; V was 0.55 mg L−1; and Zn was 0.53 mg L−1. For Ni, there were differences for years (P = 0.030), months (P < 0.001), and locations (P = 0.050), with the highest Ni value being 0.47 mg L−1. The Li level was the same for sampling month (P < 0.001). This information can help prevent potential health risks in the communities established along the river watershed who use this natural resource for swimming and fishing. Some of the contaminant concentrations found varied from year to year, from month to month and from location to location which necessitated a continued monitoring process to determine under which conditions the concentrations of toxic elements surpass existing norms for natural waters.

Effect of breed type and ionophore supplementation on growth and carcass characteristic in feedlot hair lambs

The effects of supplementing feedlot diets with ionophores and breed type were assessed on growth rate and carcass characteristics in hair lambs. Twenty four intact males, 12 Pelibuey × Dorper (PDo) and 12 Pelibuey × Damara (PDa) lambs, 17.9 ± 3.7 kg initial weight, were housed in individual pens for a 60-d feeding trial. The lambs were assigned randomly into four diets: control without additives (C); 25 µg/g monensin (M); 28 µg/g salinomycin (S); 28 µg/g S for 20 d, and 25 µg/g M for the next 40 d (SM). Each diet was supplied to six lambs. Data were analyzed as a randomized complete block design in a 4 × 2 factorial arrangement, with four diets and two breed types of hair lambs (PDo and PDa). All diets were formulated to contain 14% CP and 2.6 Mcal ME/kg dry matter. At the end of the feeding trial carcass images were recorded in the last intercostal space (12th and 13th ribs) using ultrasound equipment to measure the Longissimus dorsi muscle area and subcutaneous fat (SF). The average daily gain (ADG), daily dry matter intake, feed:gain ratio, subcutaneous fat and Longissimus dorsi area were not affected by ionophore supplementation.. The Pelibuey × Dorper group tended to show better average daily gain than Pelibuey × Damara (262 g/d and 235 g/d, respectively). Daily dry matter intake, feed:gain ratio and subcutaneous fat were not affected by breed type. The Pelibuey × Dorper lambs had greater Longissimus dorsi area (16.74 cm2) than the Pelibuey × Damara (14.29 cm2) lambs. The growth rate was not influenced by the inclusion of ionophores. Pelibuey × Dorper lambs showed better average daily gain and carcass characteristics than Pelibuey × Damara lambs.Avaliaram-se os efeitos da suplementacao de dietas de confinamento com ionoforos e da raca do animal na taxa de crescimento e nas caracteristicas de carcaca de cordeiros deslanados. Vinte e quatro machos nao-castrados – 12 cordeiros Pelibuey × Dorper (PDo) e 12 cordeiros Pelibuey × Damara (PDa), com 17.9 ± 3.7 kg de peso inicial – foram confinados em baias individuais, em um experimento de 60 dias. Os cordeiros foram distribuidos aleatoriamente em quatro dietas (D): controle sem aditivos; 25 [...]

Physicochemical Changes and Resistant-Starch Content of Extruded Cornstarch with and without Storage at Refrigerator Temperatures

Effects of extrusion cooking and low-temperature storage on the physicochemical changes and resistant starch (RS) content in cornstarch were evaluated. The cornstarch was conditioned at 20%–40% moisture contents and extruded in the range 90–130 °C and at screw speeds in the range 200–360 rpm. The extrudates were stored at 4 °C for 120 h and then at room temperature. The water absorption, solubility index, RS content, viscoelastic, thermal, and microstructural properties of the extrudates were evaluated before and after storage. The extrusion temperature and moisture content significantly affected the physicochemical properties of the extrudates before and after storage. The RS content increased with increasing moisture content and extrusion temperature, and the viscoelastic and thermal properties showed related behaviors. Microscopic analysis showed that extrusion cooking damaged the native starch structure, producing gelatinization and retrogradation and forming RS. The starch containing 35% moisture and extruded at 120 °C and 320 rpm produced the most RS (1.13 g/100 g) after to storage at low temperature. Although the RS formation was low, the results suggest that extrusion cooking could be advantageous for RS production and application in the food industry since it is a pollution less, continuous process requiring only a short residence time.