Not any type of rice performs equally to improve lactose-induced diarrhea characteristics in rats: is amylose an antidiarrheal factor?

The effectiveness of different types of rice in relation to their ability to accelerate diarrhea recovering was evaluated in a rat model of osmotic diarrhea (OD). Animals (90-100 g) received protein free diet until reaching up to 20% weight loss, followed by lactose rich diet (LRD) to induce osmotic diarrhea. Rats presenting osmotic diarrhea were divided into 4 groups, which received lactose rich diet for 4 days from 8 am to 8 pm, and one of three experimental products containing 6% rice flour differing in amylose content during the night: high (HA), intermediate (IA), and low (LA). A group fed stock diet containing equivalent amount of lactose was taken as control and allowed to recover spontaneously. Amylose and viscosity (cp at 25 °C, 10 rpm) of final products were determined. Effectiveness was expressed as the ratio between percentages of normal vs. diarrheic stools during the treatment. Fecal characteristics in this rat model improved only as result of feeding high amylose content (HA) type of rice. In this experimental model of osmotic diarrhea in young rats, the antidiarrheal effects of rice were strongly dependent on the type of diet used and appear to be related to its amylose content.

Use of ascorbic and citric acids to increase dialyzable iron from vinal (Prosopis ruscifolia) pulp

Vinal (Prosopis ruscifolia) is an ecologically important wild leguminous tree that grows spontaneously in Argentine deforested lands, the fruit of which is consumed by humans and animals. Because considerable iron content with low to intermediate availability has been previously reported in vinal pulps, its enhancement would be of interest. Iron availability was determined as iron dialyzability using an in vitro technique. Response surface methodology was used to evaluate iron availability increase after adding ascorbic and/or citric acids to vinal pulp at different mM acid/mM Fe ratios. Those ratios ranged from 0.05:1 to 9.95:1 and from 0.5:1 to 99.5:1 for ascorbic acid/Fe (AA:Fe) and citric acid/Fe (CA:Fe), respectively. The obtained second- and first-order polynomial equations showed that AA:Fe and CA:Fe molar ratios linear terms had a significant effect on iron dialyzability increase (P < or = 0.05). It was possible to enhance iron availability to a maximum of 4.6 times. Additional confirmatory experiments were made adding the same organic acids to different vinal pulps and to a traditional cake prepared with vinal pulp called "patay." There were no significant differences (p > 0.05) between predicted values obtained by the model and experimental results.

Inulin determination for food labeling

Inulin and oligofructose exhibit valuable nutritional and functional attributes, so they are used as supplements as soluble fiber or as macronutrient substitutes. As classic analytical methods for dietary fiber measurement are not effective, several specific methods have been proposed. These methods measure total fructans and are based on one or more enzymatic sample treatments and determination of released sugars. To determine inulin for labeling purposes, we developed an easy and rapid anion-exchange high-performance liquid chromatography (HPLC) method following water extraction of inulin. HPLC conditions included an Aminex HPX- 87C column (Bio-Rad), deionized water at 85 degrees C as the mobile phase and a refractive index detector. The tested foods included tailor-made food products containing known amounts of inulin and commercial products (cookies, milk, ice creams, cheese, and cereal bars). The average recovery was 97%, and the coefficient of variation ranged from 1.1 to 5% in the food matrixes. The obtained results showed that this method provides an easier, faster and cheaper alternative than previous techniques for determining inulin with enough accuracy and precision for routine labeling purposes by direct determination of inulin by HPLC with refractive index detection.

[In vitro analysis of the iron availability in fortified rice]

Cereals are rich in fiber but also in phytate which is considered the principal inhibitor of mineral availability. On this basis, iron availability of fortified rice, and the inhibitory effect of bran phytate was studied in: white rice fortified with electrolytic iron (ABF) from commercial origin; and mixtures of ABF plus 4.76% and 9.09% of rice bran (ABF2 and ABF3 respectively) to simulate brown rice. Samples were analysed before and after phytic acid hydrolysis with phytase: Dietary fiber and phytic acid were assessed according AOAC; iron availability, expressed as dialisable iron by the in vitro method of Kapsokefalou and Miller modified by Valencia et al.; iron content was assessed by AAS. Results showed that added bran depressed iron availability, 9.65%; 4.04% and 1.82% as expected (ABF, ABF2 and ABF3 respectively). After phytic acid hydrolysis iron availability reached 28.20%; 27.95% and 25.30% for the same samples. These values were not different. After phytic acid hydrolysis, fiber content of ABF2 and ABF3 were lower than before. However multiple regression analysis of the data showed that fiber had not influence on iron availability and that phytic acid would be the principal responsible of it. These results indicate that brown rice should have a higher level of iron fortification than in white rice or be combined with other foods that improve iron availability as meats, vegetables or fruits.

Lactoferrin levels in term and preterm milk

OBJECTIVE

Even though there is no doubt that human milk is the best nourishment for the neonate, there is still controversy regarding its suitability for preterm infants. The aim of this study was to contribute to the knowledge of the anti-infective properties of preterm milk, measuring lactoferrin levels, which are a non-specific protective factor.

METHODS

Samples from 26 preterm and 20 term mothers (mean gestational age +/- standard deviation, 30.9+/-2.6 and 39.5+/-1.1 weeks, respectively) were collected during the first month post-partum. Milk samples were obtained by total expression of one breast between 10 a.m. and noon. An aliquot was kept at -20 degrees C until analyzed by SDS-PAGE (sodium dodecyl sulfate-polyacrylamide gel electrophoresis). Each sample was run in duplicate.

RESULTS

Lactoferrin levels (X +/- SD) in colostrum and mature milk varied from 575.0+/-218.2 mg/dL to 459.4+/-190.7 mg/dL in preterm samples and from 970.6+/-288.6 mg/dL to 292.0+/-167.4 mg/dL in term samples. No significant differences were observed between preterm and term groups, in spite of the trend observed in colostrum, where term milk tended to show higher levels than preterm milk. Decreasing values were observed in both groups along time (ANOVA, p<0.05). However, in the preterm group, lactoferrin levels seemed to maintain rather constant values from the eighth post-partum day onwards.

CONCLUSIONS

The trend to higher levels of lactoferrin in preterm mature milk would allow maintenance of the protective effect of human milk in preterm infants in spite of the small volumes ingested by these neonates. These findings support the practice of feeding premature infants with their own mothers' milk at a time when their immune systems have not completely developed.

[Nutrient content in raw and processed foods derived from cereals and legumes. I: Centesimal composition and energetic value]

Proximate composition and metabolizable energy of raw and processed foods derived from cereals and legumes, were determined. Results can be used to revise the out of day national composition table, to incorporate data of ash, new data of dietary fiber obtained by an enzimatic hydrolysis method, asimilable carbohydrates and metabolizable energy. They also replace the composition of various foods which were compiled from foreing tables. Difference observed on values of lipids in those foods with low lipid content, are imputed to the solvents used in the extraction.

Casein to whey protein ratio in rat and human milks: effects of maternal protein intake

Maternal diet may affect milk composition quantitatively and qualitatively. The aim of this study was to assess the effects of different dietary protein quality and quantity on total milk protein concentration and on possible changes in casein:whey protein ratio as a result of differences in maternal nutritional status. Milk samples were obtained from Wistar rats fed either wheat gluten or supplemented casein at different percentages. A similar analytical scheme was applied to milk samples from lactating women belonging to different socioeconomic classes. Total milk protein in rat milk was related closely to protein quality and, to a lesser extent, to protein quantity, showing significant differences among treatment groups. Relative proportions between milk proteins were significantly affected by diet: casein: whey protein ratio was related positively to protein quality and quantity. In human milk, even though total protein content did not differ, the relative proportions between milk proteins were altered, but in a way opposite to that observed in rat milk: the whey protein:casein ratio was related positively to maternal protein intake. These modifications might influence the nutritive value or anti-infectious properties of the milk ingested by the neonate.

[Effect of lactose on the evaluation of the nutritive value of casein]

The biological evaluation of protein from dairy products such as normal and modified powdered milks where lactose is present, poses difficulties. It is known that when this sugar is contained in high concentrations, and due to its osmotic effect, it causes serious intestinal disorders in rats, thus obstructing the determination of the protein nutritional quality. In the study described herein, efforts were made to determine how lactose affects determination of the nutritional value of casein when this is evaluated by the Net Protein Utilization (NPU) procedure, and by the Relative Net Protein Ratio (RNPR) method. Thirty, and 21-day-old rats were fed with diets containing 10% and 8% of casein respectively, and lactose concentrations varying from 20% to 50%. All experiments lasted 10 days. The results demonstrated that casein's nutritional value did not differ significantly (p greater than 0.05) with lactose concentrations up to 40% in any of both methods, even though intestinal disorders were observed with more frequency and duration as lactose concentration increased.

Immunoglobulin A level in human milk from mothers delivering preterm

Little information is available on immunoglobulin content of milk from mothers of preterm babies. In this study we have measured IgA levels in samples from preterm and term mothers during the 1st month postpartum. The concentration of IgA tended to be constant in the preterm group (about 251 mg/dl) while it showed a decreasing trend in the term group (from 212.8 +/- 19.9 to 171.6 +/- 12.8 mg/dl). From day 10 onward IgA levels in preterm milk were significantly higher than in term milk (p less than 0.002). These findings support the idea that premature infants fed their own mothers' milk would benefit from more stable levels of IgA, at a time when their mucosal immune system is poorly developed.

[Enrichment of wheat flour with sunflower and soya flour for bakery products]

In order to improve the nutritive value of wheat protein, with a wheat flour, defated soybean flour and sunflower seed flour were mixed on the basis of their amino acid composition. The highest nutritive value, 86 expressed as CS, was obtained with 60% wheat flour + 28% defatted soybean flour + 12% defatted sunflower seed flour. The mixture was used to prepare: a) sea-biscuits, baked in a traditional bakery oven, and b) crackers, baked in an electric endless oven. Similar products, baked with wheat flour alone, were studied as controls. Chemical composition, total lysine, methionine, cystine, threonine and available lysine content were determine on the raw flours and mixture. Protein, fats and available lysine were determined on the bakery products. The nutritive value of the latter was assessed by their NPUop from which NPUst was calculated. The results showed an increase in the protein content of the enriched bakery products up to 60% over the controls. The nutritive value of the products was lower than the calculated figure for the raw mixture. Products b had the highest NPUst (56.4), surpassing the figures for the control (33.3) and also for product a (53.5). These values agreed with the figures for lysine availability which decreased with heat according to the cooking process. These data and the good acceptability of the crackers suggest that their enrichment with soybean and sunflowers seed concentrates asayed, could help to fulfill protein requirements in children.