Protein digestibility and protein quality of common beans (Phaseolus vulgaris) fed alone and with maize, in adult humans using a short-term nitrogen balance assay.
Various experiments using young human adults were carried out to measure the protein digestibility of common beans, fed alone and in different forms and fed together with maize as tortillas. In all, 36 young men were used. Common bean protein digestibility was significantly lower than that observed from meat, and similar to the digestibility of a textured vegetable protein soy protein product. It was also observed that forms of consumption may affect protein digestibility of beans. Using a short-term multiple intake protein quality assay method, it was found that feeding beans alone, N equilibrium was reached with an intake of 114 mg N/kg/day, while when fed with maize in a 87:13 ratio, N equilibrium was reached with 98 mg N/kg/day. This was attributed to both a complementary protein effect and an increase in protein digestibility.
Protein quality evaluation of amaranth in adult humans
This study was carried out to determine the nutritional quality of the protein of amaranth grain submitted to extrusion and popping processes, using cheese protein as reference. For the biological evaluation, the short-term nitrogen balance index method was followed with 12 experimental adult male human subjects. A Latin square series 3×3 was used (three periods, three subjects) as an experimental design balanced to minimize residual effects by randomly ordering treatments, columns and rows. The study consisted of three periods of nine days each.The first period started by feeding all subjects a low nitrogen diet, followed by increases of the protein level every two days. The levels were 0.2, 0.4, 0.6/g protein/kg/day, keeping other nutritional elements constant and adequated, including calories, minerals and vitamins. All subjects received all their meals using as a sole source of protein extruded amaranth, popped amaranth or processed cheese. Water intake was kept at a rate of 0.8–1.0 ml per calories consumed. During the study, the subjects maintained regular physical activity.Amaranthus cruentus was utilized. The extruded amaranth was prepared with the Brady Crop Cooker under conditions previously established in other studies. The popped amaranth was prepared at a 250°C temperature during 15–20 sec.The extruded and popped amaranths were provided as a sweet puree and, as all the other foods conforming the diets of each subject, they were weighed with 0.1 g of accuracy. Diet samples, as well as faeces and urine, were collected daily, which were ordered according to period and level of protein, conforming pools to determine their nitrogen content by the Kjeldahl method. True digestibility results of the protein were 101.4, 89.8 and 85.5% for cheese, extruded amaranth and popped amaranth, respectively. The statistical analysis according to the Tukey test showed that the true digestibility of the protein was the same for the two products of amaranth and different than the digestibility of cheese. Nitrogen balance index values from the equation between nitrogen intake and nitrogen retained, were 0.97, 0.86 and 0.79 for cheese, extruded amaranth and popped amaranth, respectively. The respective values between nitrogen absorbed and nitrogen retained were 0.97, 0.98 and 0.96. The Tukey test indicated that for NI to NR cheese was statistically different for the two amaranth products, which were similar between them. For the relationship NA to NR all values were statistically the same. The calculation of nitrogen intake for nitrogen equilibrium indicated that the amaranth protein is among the highest in nutritive quality of vegetable origin and close to those of animal origin products.
Dickens and the Popular Radical Imagination
List of illustrations Acknowledgements Note on editions and abbreviations used Introduction: Dickens and the popular radical imagination 1. Popular radical culture in Regency England: Peterloo and The Queen Caroline Affair 2. Dickens and nineteenth-century show trials 3. Dickens, popular culture and popular politics in the 1830s: Oliver Twist 4. Christmas is cancelled: Dickens and Douglas Jerrold writing the 1840s 5. Popular and political writing in the radical press: from Douglas Jerrold to Ernest Jones, Chartist 6. Household Words, politics and the mass market in the 1850s 7. Flunkeyism and toadyism in the age of machinery: from Bleak House to Little Dorrit Notes Bibliography Index.