Conjugated linoleic acid supplementation: lipid content and hepatic histology in healthy Wistar rats

This work aimed to evaluate the effects of the consumption of two commercial conjugated linoleic acid (CLA) mixtures on lipid content and liver histology of healthy rats. The investigation was carried out using thirty rats divided into three groups: C (control), AE (AdvantEdge®CLA), and CO (CLA One®). The concentration of CLA was 2% of feed consumption, and the animals were supplemented daily for 42 days. The total lipid content of the liver was determined, and the histology of the organ was examined by Transmission Electronic Microscopy. The results of total liver lipid contents did not exhibit significant differences between the groups. With regard to hepatic histology, it was observed that although fat globules were visibly present in higher numbers and bigger size in the CLA groups, the organ histology was considered normal since both cytoplasm and organelles showed integrity. It was concluded that even though liver microscopic images indicated the presence of fat globules in the liver, from a statistical point of view, the supplementation for 42 days did not bring about lipid accumulation, nor did it alter hepatic histology.

Glycemic profile and prebiotic potential "in vitro" of bread with yacon (Smallanthus sonchifolius) flour

The purpose of this study was to elaborate bread with yacon flour at two different levels (6% and 11%) and to analyze their proximate composition, their glycemic indices and their prebiotic potentials in vitro. Bread with 6% and 11% of yacon flour presented, simultaneously, low and moderate glycemic index. As for the prebiotic potentials, it was evident the presence of probiotic bacteria, particularly Lactobacillus. The results showed that, the addition of yacon flour on bread rendered products from low to moderate GI, with prebiotic potential, low fat and high fiber contents, according to the Brazilian food legislation.

Nutritional composition, fatty acid and tocopherol contents of buriti (Mauritia flexuosa) and patawa (Oenocarpus bataua) fruit pulp from the amazon region

Buriti and patawa are two endemic palm trees from the Amazon region. Their pulps are traditionally consumed by the local population, but are underused and lesser known worldwide. Nutritional composition, fatty acid and tocopherol contents of the two palm pulps were determined by modern analytical methods: Gas Chromatography (CG) and High Performance Liquid Chromatography (HPLC), based on the standards of AOCS (AMERICAN..., 2002) and AOAC (ASSOCIATION..., 1997), respectively. Buriti and patawa fruit pulps are highly nutritive, with respectively, high fat content (38.4% and 29.1% of dry matter (DM)), protein content (7.6% and 7.4% of DM) and dietary fibers (46% and 44.7% of DM). Buriti pulp can be considered healthy food due its high content of vitamin E (1169 µg.g-1 DM). Patawa pulp is highly oleaginous and its fatty acid composition is very similar to the ones of healthy oils, such as olive oil.

Serum lipid profile and hepatic evaluation in mice fed diet containing pequi nut or pulp (Caryocar brasiliense Camb.)

Caryocar brasiliense (popular name pequi) is widely consumed by the population of Brazilian Savannah. This fruit has a high concentration of monounsaturated fatty acids that can influence positively the lipid profile. In addition, pequi also has an important concentration of saturated fatty acids which, in turn, is associated with atherosclerosis risk. This study aimed to investigate the effect of a pequi-supplemented diet on blood lipid and glucose levels and hepatic histology. Female Albino swiss mice were divided into three groups and fed a standard chow diet (control group), chow diet supplemented with 33% pequi nut (nut group), and chow diet supplemented with 33% pequi pulp (pulp group). After 6 weeks, following an overnight fast, blood and liver were collected for posterior analyses. Serum total cholesterol and HDL-cholesterol were significantly higher in mice fed pequi-rich diets compared to the control group. Nevertheless, there was no modification in blood triglycerides, atherogenic fraction, and glucose levels. In addition, there was development of liver microvesicular steatosis related to pequi intake. In conclusion, the diets supplemented with pequi nut or pulp reduced the atherogenic risk by increasing the anti-atherogenic lipoproteins without changing the pro-atherogenic fraction in mice.

Effect of whey protein concentrate on texture of fat-free desserts: sensory and instrumental measurements

It is important to understand how changes in the product formulation can modify its characteristics. Thus, the objective of this study was to investigate the effect of whey protein concentrate (WPC) on the texture of fat-free dairy desserts. The correlation between instrumental and sensory measurements was also investigated. Four formulations were prepared with different WPC concentrations (0, 1.5, 3.0, and 4.5 wt. (%)) and were evaluated using the texture profile analysis (TPA) and rheology. Thickness was evaluated by nine trained panelists. Formulations containing WPC showed higher firmness, elasticity, chewiness, and gumminess and clearly differed from the control as indicated by principal component analysis (PCA). Flow behavior was characterized as time-dependent and pseudoplastic. Formulation with 4.5% WPC at 10 °C showed the highest thixotropic behavior. Experimental data were fitted to Herschel-Bulkley model. The addition of WPC contributed to the texture of the fat-free dairy dessert. The yield stress, apparent viscosity, and perceived thickness in the dairy desserts increased with WPC concentration. The presence of WPC promotes the formation of a stronger gel structure as a result of protein-protein interactions. The correlation between instrumental parameters and thickness provided practical results for food industries.

Physicochemical and sensory profile of rice bran roasted in microwave

The purpose of this study was to evaluate the physical, chemical, and sensory changes in bran from three rice cultivars according to microwave roasting time. This study analyzed three rice cultivars, BRS Sertaneja (S), BRS Primavera (P), and IRGA 417 (I) determining the color parameters (L*, a*, and b *) at 6, 9, 12, 15, and 18 minutes of roasting time. After applying the difference from control test, the rice brans with different characteristics aroma and flavor were selected: S and P roasted for 9 and 15 minutes and IRGA 417 roasted for 9, 12, and 15 minutes. These samples were characterized by Free-Choice Profile descriptive sensory analysis, and their chemical composition was also determined. The longer the roasting process, the higher the roasted flavor intensity and aroma. The IRG 417 cultivar roasted for 12 minutes showed a sweeter flavor and aroma. After roasting, the brans remained rich in protein and lipid and presented higher fiber content and lower reducing sugar and phytic acid content. Microwave roasting for 12 minutes can be a viable option for improving the sensory functional and nutritional characteristics of the rice bran considering its use in food products.

Deep-fat frying of meat products in palm olein

This study investigated the discontinuous frying of breaded meat products in palm olein in a 28 L-electric fryer maintained at 182 ºC for 8 hours a day. Three 400-500 g batches of meat products were fried for 4.5 minutes daily. For comparison purpose, thermoxidation tests were performed using inert material with added moisture and without the addition of f ood (heating only). The total polar compound content did not reach the 25% limit, and nor did the formation of polymerized products exceed 5%, which indicates the good frying performance of palm olein for frying. Other analytical parameters and rapid tests were also evaluated. The sensory attributes, such as odor, colour, and foam formation determined when the frying oils should be discarded. The addition of water to the inert material contributed to the final value of 1.00 ± 0.01% (in palmitic acid), while the oil subjected only to heating reached respectively 0.26 ± 0.02%, and the oils used to fry breaded meat and breaded chicken reached 0.38 ± 0.00% and 2.35 ± 0.01%, respectively. This suggests a protective effect of the water during frying since the oil subjected only to heating was more prone to degradation.

Nutritional value and fatty acid composition of some traditional Argentinean meat sausages

The aim of this study was to determine the nutritional composition (moisture, protein, carbohydrates, and total fat) of some meat products produced in the northeastern Argentina, analyzing fatty acids composition, polyunsaturated/saturated fatty acid ratio PUFA/SFA ratio (polyunsaturated/ saturated fatty acids), n-6/n-3 ratio, and CLA (conjugated linoleic acid) content. Thirty traditional meat products produced by different processes were used. The samples were classified into 4 different categories as follows: salamín (dry cured and fermented sausage), chorizos (raw sausage), chorizo ahumado (cooked and smoked sausage), and morcilla (cooked sausage). From the results obtained it can be said that the total carbohydrate contents of the salamín studied were slightly lower; fat content of raw chorizo was significantly lower, and protein content of chorizo ahumado was significantly higher than those comparison from databases from other regions of Argentina, USA, and Spain. Except for chorizo, which has a value lower than 0.4, the PUFA/SFA-stearic ratio of the other products were a little higher than those reported by other researchers. CLA (Conjugated linoleic acid) contents between 0.03% and 0.19% were detected. The results obtained indicate that salamín produced in northeastern Argentina, Chaco state, shows high protein and PUFA (Polyunsaturated fatty acids) contents, and low atherogenic and thrombogenic indexes, which makes it a more healthful product than those of similar composition produced in other countries.

Sesame and flaxseed oil: nutritional quality and effects on serum lipids and glucose in rats

This study evaluated the nutritional value of sesame and flaxseed oils and their effects on the lipid and glucose profile of rats fed diets containing different fat combinations. Fatty acid composition, refractive index, and iodine and saponification values were analyzed to characterize the oils. In the biological assay, Wistar rats were fed different diets, whose fat composition consisted of varying combinations of flaxseed oil, sesame oil, and animal fat. The primary constituents of the sesame oil were oleic (28.6%), linoleic (28.4%), and lauric acid (14.6%); for the flaxseed oil they were alpha-linolenic (39.90%), oleic (17.97%) and linoleic acid (12.25%). The iodine and saponification values of the oils were within the reference range. Rats fed flaxseed oil-based diets had the lowest serum cholesterol values, whereas rats fed diets with flaxseed oil + sesame oil + animal fat had the highest glucose levels. HDL levels decreased significantly with flaxseed oil. Sesame and flaxseed oils are sources of polyunsaturated fatty acids (PUFA), and the flaxseed oil-based diet had a hypocholesterolemic effect, whereas sesame oil showed oxidative stability since it contains high levels of monounsaturated and saturated fatty acids.

Incorporation and profile of fatty acids in tilapia fillets (Oreochromis niloticus) fed with tung oil

The acceptance of tung oil enriched diet and the incorporation of conjugated linolenic acid - CLnA into fillets of Genetically Improved Farmed Tilapia (GIFT) were investigated. The diet was well accepted, and after 10 days CLnA was incorporated into the fillets with a 1.02% content of total fatty acids (FA). In addition, biosynthesis of the conjugated linoleic acid isomers - CLA (0.31% of fillet total FA content) from CLnA, and the presence of alpha-linolenic acid - LNA (1.08% of fillet total FA content), eicosapentaenoic acid - EPA (2.85% of fillet total FA content) and docosahexaenoic acid - DHA (3.08% of fillet total FA content) were observed. Therefore, the consumption of this fish can increase the intake of different FA (CLnA, CLA, LNA, EPA and DHA), which play an important role in human metabolism.

Okara, a soymilk industry by-product, as a non-meat protein source in reduced fat beef burgers

Okara is a by-product generated during the manufacture of soymilk and tofu. Wet okara was added to beef burgers at 0%, 20%, and 25%. The effects of okara on certain physicochemical, textural, and sensory properties of reduced fat beef burgers were investigated. The beef burgers formulated with okara (104.0-106.0 kcal/100 g) had 60% less calories than commercial beef burgers (268.8 kcal/100 g). The texture profile analysis showed that the addition of wet okara led to a significant increase in hardness (p < 0.05) and a concomitant reduction in the values of chewiness, springiness, and cohesiveness. Lower sensory scores (p < 0.05) of flavour were observed in the beef burgers containing 25% wet okara. However, the sensory evaluation results showed that juiciness, appearance, tenderness, and overall acceptability of beef burgers formulated with okara did not differ statistically from that of the control (0% okara). Wet okara (20%) can be used as a non-meat protein source in the production of reduced-fat beef burgers without changing their sensory quality.

The effect of acid hydrolysis on the technological functional properties of pinhão (Araucaria brasiliensis) starch

Technological functional properties of native and acid-thinned pinhão (seeds of Araucária angustifolia, Brazilian pine) starches were evaluated and compared to those of native and acid-thinned corn starches. The starches were hydrolyzed (3.2 mol.L-1 HCl, 44 ºC, 6 hours) and evaluated before and after the hydrolysis reaction in terms of formation, melting point and thermo-reversibility of gel starches, retrogradation (in a 30-day period and measurements every three days), paste freezing and thawing stability (after six freezing and thawing cycles), swelling power, and solubility. The results of light transmittance (%) of pastes of native and acid-thinned pinhão starches was higher (lower tendency to retrogradation) than that obtained for corn starches after similar storage period. Native pinhão starch (NPS) presented lower syneresis than native corn starch (NCS) when submitted to freeze-thaw cycles. The acid hydrolysis increased the syneresis of the two native varieties under storage at 5 ºC and after freezing and thawing cycles. The solubility of NPS was lower than that of native corn starch at 25, 50, and 70 ºC. However, for the acid-thinned pinhão starch (APS), this property was significantly higher (p < 0.05) when compared to that of acid-thinned corn starch (ACS). From the results obtained, it can be said that the acid treatment was efficient in producing a potential fat substitute from pinhão starch variety, but this ability must be further investigated.

Characterization of goat milk and potentially symbiotic non-fat yogurt

Combining prebiotics and probiotic microorganisms improve quality in the formulation of foods. In this paper, the characteristics of goat milk and symbiotic yogurt were studied. Raw goat milk was analyzed and the skimming process was optimized. For the formulation of a potentially non-fat symbiotic yogurt made with skimmed goat milk, inulin, gelatin, sugar, and Streptococcus salivarius subsp. thermophilus, Lactobacillus delbrueckii subsp. bulgaricus and Lactobacillus casei subsp. rhamnoshus. Chemical characteristics, acceptability, and viability of lactic acid bacteria and probiotic culture were assessed. The protein and fat content of the raw milk was 2.90 and 3.56 g/100 mL, respectively. The optimum skimming process was obtained at 9,800 rpm and 4 °C for 15 minutes. The product formulated had a protein and fat content of 4.04 to 0.04 g/100 mL, good sensory properties, and acceptability of 95%. The lactic bacteria count was 9 × 10(7) CFU mL- 1, and probiotic culture count was higher than 1 × 10(6) CFU mL- 1, which guarantees their effect and capacity to survive in the digestive tract and spread in the intestine. The yogurt was stable during the 21 days of storage. Therefore, this study shows that goat milk yogurt is an adequate delivery vehicle of the probiotic culture L. casei and inulin.

Effect of a high fat maternal diet on body composition and bone development in male offspring

Direct high fat (HF) feeding has adverse effects on body composition and bone development in rodents. However, it is unclear whether maternal HF feeding has similar effects in male rat offspring. The objectives of this thesis were to determine if maternal HF feeding altered body composition, plasma hormones, bone development, and bone fatty acid composition in male offspring at weaning and 3 months of age. Maternal HF feeding increased bone mass and altered femur fatty acid composition at weaning, without differences in fat mass, lean mass, plasma hormones, or bone mass (femur or lumbar vertebrae). However, early differences did not persist at 3 months of age or contribute to lower bone strength – following consumption of a control diet post-weaning. These findings suggest that maternal HF feeding can alter body composition and bone development in weanling male offspring, without long-lasting effects if a healthy control diet is consumed post-weaning.

Modalities of exercise training on liver fat accretion and inflammatory markers in ovariectomized rats

Les facteurs de risque des maladies cardiovasculaires, telle, que la détérioration du profil lipidique, deviennent plus prononcés après la ménopause, ce qui fait de la maladie coronarienne, l’une des principales causes de décès chez les femmes ménopausées. Une proportion importante de femmes prennent du poids après la ménopause en particulier dans la région abdominale entraînant par conséquent des perturbations métaboliques. Des données récentes suggèrent également que l’absence des œstrogènes observée à la ménopause favorise le développement de la stéatose hépatique. Cette dernière a été incriminée pour incriminée dans le développement de la résistance à l'insuline, et est de ce fait considérée comme une composante hépatique du syndrome métabolique. Il est impératif d'établir des stratégies visant à contrecarrer l'accumulation de graisse dans le foie et l’accroissement du tissu adipeux chez les femmes ménopausées, en tenant compte que l'utilisation de l'hormonothérapie substitutive est de nos jours moins soutenue. Les quatre études de la présente thèse ont été conduites pour tenter de fournir des informations sur le traitement et la prévention de l’augmentation de la masse graisseuse et de la stéatose hépatique qu’entraîne la suppression des œstrogènes, à travers les modifications du mode de vie (diète et exercice physique) chez la rate ovariectomizée (Ovx); un modèle animal de la ménopause. Dans les deux premières études nous nous sommes concentrés sur l’augmentation de la masse graisseuse et sa reprise suite à une perte de poids. Dans la première étude, nous avons montré que les rates Ovx qui ont suivi un programme de restriction alimentaire (FR) ont diminué significativement (P < 0.01) leur poids corporel, leur contenu en graisses intra-abdominales ainsi que leurs triacylglycérols (TAG) hépatiques, comparativement aux rates Ovx nourries à la diète normale. De plus, l’entraînement en résistance (RT) a prévenu la reprise de poids corporel ainsi que l’accroissement du tissu adipeux et l’accumulation de lipides dans le foie des rates Ovx, après l’arrêt du régime amaigrissant. Les résultats de la deuxième étude ont confirmé l'efficacité de la restriction alimentaire associée à l’entraînement en résistance (FR + RT) dans la réduction du poids corporel, des lipides dans le foie et le tissu adipeux chez les rates Ovx. Tenant compte des résultats de notre première étude, l’entraînement en résistance seulement a constitué un atout pour atténuer le poids corporel et la masse grasse reprise par les rates Ovx suite à un programme de perte de poids (FR + RT); bien que l'impact ait été moindre comparé au maintien seul de la restriction alimentaire. De la même manière que la supplémentation en œstrogènes, les résultats de la troisième étude indiquent que l'entraînement en endurance mené concurremment avec l’ovariectomie a significativement atténué l'accumulation de lipides dans le foie ainsi que dans le tissu adipeux. Toutefois, l’entraînement en endurance effectué avant l'ovariectomie n'a pas protégé contre l'accumulation des graisses qu’entraîne l'ovariectomie, si celui-ci est interrompu après l'ovariectomie. Enfin, pour compléter les résultats antérieurs, nous avons montré dans la quatrième étude que l’expression des gènes impliqués dans la synthèse de lipide; SREBP-1c, SCD-1, ChREBP, et ACC dans le foie a augmenté après le retrait des œstrogènes, tandis qu’une diminution (P < 0.01) des niveaux d'ARNm de PPAR-α a été observée. De plus, l'expression hépatique des gènes des cytokines pro-inflammatoires incluant IKKβ, IL-6 ainsi que le contenu protéinique de NF-кB étaient augmentés (P < 0.01) chez les rates Ovx par rapport aux rates ayant subi une Ovx simulée (Sham). Toutes ces perturbations ont été améliorées avec la supplémentation en œstrogènes seulement, ainsi qu'avec l'entraînement en endurance seulement. Dans l'ensemble, nos résultats indiquent que l'exercice physique (en résistance ou en endurance) a un impact significatif sur la réduction de l'accumulation des lipides dans le foie et dans le tissu adipeux des rates Ovx. De plus, chez les rates Ovx, l’entraînement en endurance mimerait les effets des œstrogènes sur l'expression des gènes impliqués dans l'accumulation de lipides et l’inflammation préclinique dans le foie.