A comparison of effects of lard and hydrogenated vegetable shortening on the development of high-fat diet-induced obesity in rats.

BACKGROUND: Obesity is associated with increased consumption and preference for dietary fat. Experimental models of fat-induced obesity use either lard or vegetable shortening. Yet, there are no direct comparisons of these commonly used fat sources, or the influence of their fatty acid composition, on the development of diet-induced obesity. OBJECTIVE: To compare the effects of lard and hydrogenated vegetable-shortening diets, which differ in their fatty acid composition, on weight gain and the development of obesity and insulin resistance in rats. METHODS AND DESIGN: Male Wistar rats were fed ad libitum for 14 weeks high-fat diets containing either (1) high vegetable fat (HVF, 60 kcal% from vegetable shortening) or (2) high lard fat (HLF, 60 kcal% from lard). Rats fed normal-fat (NF, 16 kcal% from vegetable shortening) diet served as control. Body weight, food intake, adipose tissue mass, serum 25[OH]D3, glucose, insulin and fatty acid composition of diets were measured. RESULTS: Rats fed either of the two high-fat diets had higher energy intake, weight gain and fat accretion than rats fed normal-fat diet. However, rats fed the HLF diet consumed more calories and gained more weight and body fat with greater increases of 32% in total (158.5±8.2 vs 120.2±6.6 g, P<0.05), 30% in visceral (104.4±5.2 vs 80.3±4.2 g, P<0.05) and 36% in subcutaneous fat mass (54.1±3.6 vs 39.9±3.1 g, P<0.05), compared with rats fed the HVF diet. Higher visceral adiposity was positively correlated with serum insulin (r=0.376, P<0.05) and homeostatic model assessment insulin resistance (r=0.391, P<0.05). CONCLUSION: We conclude that lard-based high-fat diets accentuate the increase in weight gain and the development of obesity and insulin resistance more than hydrogenated vegetable-shortening diets. These results further point to the importance of standardizing fatty acid composition and type of fat used in determining outcomes of consuming high-fat diets.

Toxicidad medular secundaria a primoinfección por virus de Epstein-Barr en paciente con enfermedad de Crohn en tratamiento con tiopurínicos / Bone marrow toxicity secondary to a primary Epstein-Barr infection in a patient with Crohn's disease on thiopurines treatment

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Obesogenic phenotype of offspring of dams fed a high multivitamin diet is prevented by a post-weaning high multivitamin or high folate diet.

BACKGROUND: High multivitamin (10-fold AIN-93G, HV) diets fed during pregnancy to Wistar rats increase characteristics of metabolic syndrome in offspring when weaned to the recommended vitamin (RV) diet. OBJECTIVE: To determine whether the effects of HV gestational diets on obesogenic phenotypes in the offspring arise as a consequence of altered hypothalamic control of feeding behavior and if their increased food intake could be prevented by feeding them HV or high folate (10-fold folate, HFol) diets. METHODS: Male offspring of dams fed HV diet during pregnancy weaned to RV, HV or HFol diets were compared with those born to RV dams and weaned to RV diet for 29 weeks. Food intake over 72 h and body weight were measured bi-weekly and weekly, respectively. Glucose response to a glucose load was measured at 18 weeks post weaning. Hypothalamic gene expression of feeding-related neuropeptides including neuropeptide Y, pro-opiomelanocortin (POMC), insulin receptor, leptin receptor, brain-derived neurotrophic factor (BDNF), receptors for dopamine (DopaR1/2/5) and serotonin (SeroR1A/2A/2C), as well as global DNA methylation and brain and plasma folate concentrations were measured at 29 weeks post weaning. RESULTS: HV or HFol pup diets increased brain and plasma folate concentrations and prevented the increase in food intake (5%, P=0.03), body weight (8%, P=0.0006) and glucose response to a glucose load (36%, P=0.02) found in those fed the RV diet. Expression of anorexigenic POMC (P=0.004) and BDNF (P=0.02) was higher, and DopaR1 was lower (P=0.06) in pups fed the HV diet. The HFol pup diet partially brought BDNF to the control level (P=0.02) and lowered SeroR2A (P=0.008). Expression of other genes was unaffected. Global DNA methylation was similar among the diet groups. CONCLUSION: The obesogenic phenotype in offspring from HV-fed dams is prevented by feeding HV or HFol pup diets, possibly due to post-weaning modulation of food intake regulatory mechanisms.

Pressure-aided microwave rubber vulcanization in a ridged three-zone cylindrical cavity

The characteristics of pressure-assisted microwave vulcanization of rubber were studied in a monomode cavity. For this purpose a modified cylindrical cavity was designed taking into account the external pressure of dielectric molds at the same time that heating was taking place. The monitoring of dielectric properties of rubber sample during the vulcanization process was demonstrated to be of the utmost importance to correlate the evolution of the rubber when is heated with microwaves with the main processing parameters (viscosity and degree of cure). The results obtained looked promising as the vulcanization rates were accelerated giving vulcanized samples comparable in quality to conventional treatment methods.

Thermal inactivation of mushroom polyphenoloxidase employing 2450 MHz microwave radiation.

Browning reactions in fruits and vegetables are a serious problem for the food industry. In mushrooms, the principal enzyme responsible for the browning reaction is polyphenoloxidase (PPO). A microwave applicator has been designed and used for studying mushroom PPO inactivation. The effects of microwaves and conventional heating on the kinetics of the monophenolase and diphenolase activities of PPO were studied. Conventional and microwave treatments produce different enzyme intermediates with different stability and kinetic properties. We describe how considerable time can be saved during microwave inactivation of the enzyme compared with the time needed when conventional hot-water treatment is used, resulting in greater profitability and enhanced quality. The short exposure time required for samples irradiated with microwaves is very important for maintaining the quality of mushrooms. The fast microwave treatment used resulted in an increase in antioxidant content and a considerable decrease in browning.

Enzyme inactivation analyses for industrial blanching applications employing 2450 Mhz monomode microwave cavities.

Browning reactions in fruits and vegetables are recognized as a serious problem for the European food industry, particularly for the mushroom sector. The major enzyme responsible for the browning reaction is polyphenoloxidase (PPO). In this paper considerable reduction has been achieved in both the time and temperature required for complete microwave enzyme inactivation compared to conventional hot-water treatments, which can be translated into both increased benefits and enhanced quality products for the food industry. Furthermore, the short exposure time required for complete inactivation of aqueous solutions of PPO irradiated with microwaves within monomode cavities is very important to reduce the browning rate of mushroom extracts, and could lead to a much greater product profitability when treating whole processed mushrooms.