Patricio Hevia

Value of a tomato byproduct as a source of dietary fiber in rats.

A residue consisting of tomato peel and seeds is a byproduct of thetomato paste industry. This product had, after drying and grinding,101.4 g water, 175.6 g protein, 95.9 g lipids, 36.4 g ash and590.7 g total carbohydrates per kilogram of residue. The carbohydratesin the residue were mainly dietary fiber (495.3 g) from which 405.4 gwere insoluble fiber. Additionally, the residue had ascorbic acid 0.25 g, P 3 g, Ca 1.7 g, K 13.1 g, Mg 2.4 g, Cu 0.013 g, Fe0.248 g, Mn 0.018 g and Zn 0.174 g per kilogram of residue. Theresidue fed to rats at increasing concentrations in the diet (0, 134, 263and 387 g/kg diet) over 18 days had no effect on body weight gain;caused an increase in food intake and slightly reduced feed efficiency.Incorporation of the residue in the diet caused a substantialincrease in fecal mass, which was proportional to the dietary fiber providedby the residue (r = 0.89); apparent absorption of protein, energy,Ca, Mg, Fe, Zn and Cu present in the diets was reduced. These reductions were proportional to the amount of dietary fiber provided by the residueand became substantial when the residue was included at 263 or 387g/kg. However, when the residue was included at 134 g/kg, little effect onthe apparent absorption of the dietary nutrients was noted. Because thisconcentration provided the rats with approximately 10 times more fiberthan that recommended for humans, one can expect that if this tomatoresidue were consumed at concentrations recommended for humans, itshould have no effect on nutrient availability. These results indicate that thistomato residue represents an attractive source of fiber, which in rats had alow apparent absorption (52–56%). In addition, it was very effective inincreasing fecal mass with no negative effects on growth performance.

Application of a colorimetric method to the determination of the protein content of commercial foods, mixed human diets and nitrogen losses in infantile diarrhoea

Recently we reported on the application of a method for protein determination which measures nitrogen in Kjeldahl digests colorimetrically. This procedure has the advantage of eliminating the distillation and titration steps of the Kjeldahl method and it is ideal for nutritional studies, since many samples can be run in a single day. Accordingly, the purpose of the present report was to extend the application of this method to the determination of the protein content of commercially available foods such as dairy products, dry cereals or cereal based products and legumes and also to evaluate this method in the determination of the protein content of the mixtures of cooked foods served during lunch at the cafeteria of the Universidad Simón Bolívar, Caracas. In both cases the results of the colorimetric nitrogen agreed very well with those obtained by the macro Kjeldahl, indicating that the colorimetric method may be used in monitoring the protein content of commercial foods and in evaluating the protein offered in institutional food services. Finally, to further demonstrate the value of this method in clinical trials, we used it to monitor the daily nitrogen intake and nitrogen losses in 43 male young children with acute diarrhoea, and 15 with persistent diarrhoea fed liquid formulae, and showed that protein digestibility and retention were higher in persistent than in acute diarrhoea. The severity of acute diarrhoea affected negatively (r = -0.62) the percentage of protein absorbed, whereas the protein absorbed (r = 0.70) and retained (r = 0.55) correlated positively with protein consumption.(ABSTRACT TRUNCATED AT 250 WORDS)

Quantitative determination of nitrogen content in plant tissue by a colorimetric method

Abstract This study was to evaluate the applicability of a colorimetric method in measuring the nitrogen (N) concentration in samples of vegetable origin. In order to do this, the same samples were analyzed with a colorimetric, and macro‐ and microKjeldahl methods. The colorimetric method has been used successfully in the determination of N in nutritional studies with rats and humans. The present procedure has the advantage of eliminating the distillation and titration steps of the Kjeldahl method and it is practical for nutritional studies, since many samples can be run in a single day. The N concentration was measured in leaves of two tropical grasses: Paspalum fasciculatum Willd. ex Flugge and Hyparrhenia rufa (Nees) Stapf, and a Standard Reference Material (SRM 1547 Peach Leaves). In all cases, there were no significant difference (P>0.05) in N concentration in these plant materials using the colorimetric, and micro‐ and macroKjeldahl methods. There was a good agreement between the N concentration of ...

Effect of food intake on protein quality measured in chicks by traditional or biochemical methods

Previous studies have shown that the activities of the hepatic enzymes xanthine dehydrogenase and nucleoside phosphorylase, as well as the uric acid excreted, can be used to determine the quality of the protein consumed in chickens, in a short time and using a small amount of the test protein. A common observation in protein quality evaluation is that the food intake of the control animals is considerably greater than that observed in those receiving proteins of low quality. Since this can affect the results, this study measured the quality of garbanzo bean and black bean proteins in chickens fed these beans ad libitum, feeding the bean diets at the level observed in the controls (soy protein+methionine) by enteral intubation or pair feeding the controls with the amount of food consumed by the chickens receiving the bean diets. In every case, protein quality was determined by protein efficiency ratio, net protein utilisation or the biochemical methods used in this study. The results showed that, when fed ad libitum, the animals assigned to the bean diets exhibited a lower food intake than the controls but, by tube feeding, food intake was made equal in both groups. Equal consumption, between these groups, was also obtained by reducing the amount of food offered to the controls to the levels measured in the groups assigned to the bean diets (pair feeding). These feeding strategies had a marked effect on growth, carcass protein content, protein catabolism and also in the results of protein quality. Thus, the control whose intake was reduced grew less, accumulated less protein in tissues and catabolised more of the protein consumed than the control fed ad libitum. In contrast, the chickens assigned to the bean diets, but whose food intake was increased by tube feeding, grew better, accumulated more protein in tissues and catabolised less protein. In general, the results of these experiments confirm the effectiveness of the biochemical methods for estimating protein quality and indicate that the protein quality of both garbanzo beans and black beans increased when it was measured at a food intake equivalent to that measured in the control animals. Since the overall purpose of this study was to evaluate techniques for protein quality determination meant to be applicable to humans nutrition rather than poultry nutrition, single proteins were used instead of combinations of proteins.

Nutritional evaluation of the soy-whey milk analogLa colina

The milk analogLa colina is a product which contains mainly whey, soy protein isolate and vegetable oil, designed for infants since one year, children, adolescents and adults of all ages. The concept behind this product is to offer an alternative to milk consumption which during the last decade has decreased dramatically in Venezuela mainly due to its high price and low availability. Accordingly, the purpose of this study was to evaluate nutritionally this new product in order to determine if from a nutritional stand point it could represent a valid alternative to milk consumption. The results showed thatLa Colina offers the same amount of protein, energy, vitamin A, calcium, phosphorus and potassium as whole milk powder and more sodium, iron and zinc. In addition, a rat assay showed that the energy in these two products is equally available and even though the proteins inLa colina are 3.9% less digestible, their quality determined by growth, PER or the nitrogen retained are excellent and identical to the quality of the proteins in milk. These results agreed with the theoretical chemical score of the proteins of this new product, which indicated that the amino acid profile of the mixture can fulfill the amino acid requirements of children, adolescents an adults. Both milk andLa colina are products with a high fat content. The fat in this new product however, is vegetable oil and therefore it has a more convenient fatty acid profile than whole milk and about one third of its cholesterol. In short, these results showed thatLa Colina from a nutritional point of view is an excellent alternative to milk consumption.