Effects of Popping on Nutrient Contents of Amaranth Seed

Amaranth seeds can be popped by heating. The traditional method of popping in a skillet is simple, but it is difficult to control the heating time and temperature. To overcome these disadvantages, we developed a fluidized bed continuous processing system based on hot air heating for producing popped amaranth seeds in bulk. Using this system, we evaluated the effects of heat treatment at 260 °C for 15 s on the contents of B-group vitamins and essential and trace elements in amaranth seeds. The results showed that the treatment did not affect the content of B-group vitamins, and the recovery for essential and trace elements was 97–196 %. This popping system is useful for processing amaranth seeds in terms of the product quality and nutrition.     

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.     

The nutritive value of amaranth grain (Amaranthus caudatus)

The nutritional value of three pale seeded and one dark seeded variety ofAmaranthus caudatus was studied by chemical analyses and in balance experiments with growing rats. Effects of processing: popping, toasting and flaking were also examined. The pale seeds contained about 14% protein, 10% fat, 2.5% ash, 64% starch and 8% of dietary fibre. The black seeds had a much higher content of fibre (16%). The concentration of essential amino acids were high. Lysine ranged from 5.2–6.0 g/16 g N in the grains, and the limiting amino acids were leucine followed by valine or threonine. The grains contained small amounts of tannin (0.3%) and heat-labile protease inhibitor activity, at levels typical of common cereal grains. Digestibility of protein in the pale seeds was high (87%) and quite unaffected by processing. Protein digestibility of the black seeds was lower, and the digestibility was further reduced by toasting. The biological value of the protein was similar in all products, and very high. The content of minerals varied among varieties and was also affected by processing. Phytate: zinc molar ratios were high in most products, and rats fed the amaranth samples with the lowest zinc contents were in negative zinc balance. In general, femur zinc concentrations were rather low. However, amaranth is an unconventional crop which deserves further attention.     

Limiting amino acids in raw and processed amaranth grain protein from biological tests

Amino acid supplementation studies with young rats were carried out using raw and processed amaranth grain (A. cruentus) of dark- and cream- or light-colored seeds. The results of various studies repeatedly indicated that threonine is the most limiting amino acid in raw and processed, dark and cream-colored grain. Protein quality as measured either as NPR or PER was improved by threonine addition alone or with other amino acids and decreased liver fat to values similar to those measured with casein. This finding contradicts the reports that state that leucine, determined by chemical score, is the most limiting amino acid. Leucine addition alone or with other amino acids did not improve protein quality. The study confirmed cream-colored grain to be nutritionally superior to dark grain and that properly processed grain, light- or dark-colored, has higher protein quality than raw grain.INCAP Publication I-1525     

Evaluation of pumpkin seed products for bread fortification

Pumpkin seed products (raw, roasted, autoclaved,germinated, fermented, pumpkin protein concentrate and pumpkin proteinisolate) were incorporated into wheat flour to produce blends with proteinlevels of 15, 17, 19 and 21%. Dough properties were evaluated by afarinograph; loaves of breads were evaluated by a taste panel for crustcolor, crumb color, crumb texture, flavor, and overall quality. Resultsindicated that pumpkin seed products can be added to wheat flour up toa 17% protein level for raw, roasted and autoclaved pumpkin meal, 19%level for germinated, fermented and pumpkin protein concentrate and21% level for pumpkin protein isolate without a detrimental effecton dough or loaf quality. On the other hand, the addition of pumpkin seedproteins resulted in increasing protein, lysine and mineral contentscompared to the control. While lysine and tryptophan were the first andsecond limiting amino acids in the control bread, tryptophan and lysinewere the first and second limiting amino acids for raw, roasted, autoclaved,germinated and fermented pumpkin meal; valine and lysine and valine andtotal sulfur amino acids were the first and second limiting amino acids forpumpkin protein concentrate and isolate, respectively. In vitro protein digestibility improved when the pumpkin seed proteinswere added.     

Effects of Popping on the Endosperm Cell Walls of Sorghum and Maize

The structure of the vitreous endosperm of raw and popped grains of popcorn maize and sorghum has been examined by light and scanning electron microscopy. In both cereals, popping produces everted grains consisting of expanded endosperm foam attached to the pericarp and embryo tissue. As previously reported, each bubble of the foam is formed from an individual starch granule inflated by internal steam pressure. Large fissures may contribute significantly to the expansion of the endosperm foam. The cell walls of the vitreous endosperm of both cereals are shattered into small fragments, which separate slightly as the cell contents expand during popping. Despite this, the endosperm cells retain their polygonal outline. Intact cell walls of raw endosperm, wall fragments from popped endosperm foam, and fragments isolated after treatment of the foam withalpha -amylase, were visualised through the autofluorescence of their ferulic acid content. The in vitro digestibility of popped sorghum was unchanged compared to raw sorghum, whereas that of wet-cooked sorghum was greatly reduced. It is suggested that popping-induced wall fragmentation improves the accessibility of the protein and starch reserves of the endosperm to digestive enzymes.     

Gluten-Free Breads and Cookies of Raw and Popped Amaranth Flours with Attractive Technological and Nutritional Qualities

Gluten-free bakery foodstuffs are a challenge for technologists and nutritionists since alternative ingredients used in their formulations have poor functional and nutritional properties. Therefore, gluten-free bread and cookies using raw and popped amaranth, a grain with high quality nutrients and promising functional properties, were formulated looking for the best combinations. The best formulation for bread included 60–70% popped amaranth flour and 30–40% raw amaranth flour which produced loaves with homogeneous crumb and higher specific volume (3.5 ml/g) than with other gluten-free breads. The best cookies recipe had 20% of popped amaranth flour and 13% of whole-grain popped amaranth. The expansion factor was similar to starch-based controls and the hardness was similar (10.88 N) to other gluten-free cookies. Gluten content of the final products was around 12 ppm. The functionality of amaranth-based doughs was acceptable although hydrocolloids were not added and the final gluten-free products had a high nutritional value.     

Nutritive value of prickly pear seeds,Opuntia ficus-indica

Results are reported on the nutritional quality of prickly pear seeds,Opuntia ficus-indica. The seeds contained 16.6% protein, 17.2% fat, 49.6% fiber and 3.0% ash. The meal showed a high amount of iron (9.45 mg %). The contents of Mg, P, K, Zn and Cu were nutritionally significant contributing approximately 10–20% of the Recommended Dietary Allowances (RDA) of these elements per 100 g of dry weight. The amount of Ca represented less than 10% of the RDA for that element. Aspartic acid, glutamic acid, arginine and glycine were the most abundant amino acids making nearly half of the total amino acids content. The seeds were rich in sulfur amino acids (methionine + cystine). Lysine was the first limiting amino acid resulting in a chemical score of 62 for the protein. The in-vitro protein digestibility and the calculated protein efficiency ratio were 77% and 1.82 compared to 90% and 2.50, respectively, for ANRC casein.     

Glycemic index of grain amaranth, wheat and rice in NIDDM subjects

Glycemic index of grain amaranth, wheat and rice preparations was studied in noninsulin dependent diabetic subjects. Diets containing 50 g carbohydrate equivalent were given and post-prandial blood glucose estimated at different intervals. Glycemic index calculated for different experimental diets showed that GI of amaranth-wheat composite flour diet (25∶75) was the least (65.6%) followed by wheat diet (65.7%), rice diet (69.2%), amaranth-wheat flour 50∶50 (75.5%), and popped amaranth in milk (97.3%). Therefore 25∶75 combination of amaranth and wheat, wheat and rice can be considered low GI food, 50∶50 grain amaranth and wheat medium GI food and popped amaranth and milk combination high GI food.     

Chemical composition and nutritional quality ofCleome dolichostyla seeds

Seeds ofCleome dolichostyla were analysed for proximate composition, mineral element contents and amino acid composition, in-vitro protein digestibility (IVPD) and calculated protein efficiency ratio (C-PER). The seeds (dry basis) were rich in oil (32.1%), protein (24.6%) and fiber (17.8%) content. The contents of various mineral elements mg/100 g) were: Ca=1970, P=493, Mg=127, Na=35, K=465, Fe=71.97, Zn=2.25, Cu=0.44 and Mn=1.45. Aspartic acid, glutamic acid, glycine, arginine and histidine were the major amino acids inC. dolichostyla seed protein accounting for half of the total amino acids. Lysine was the most limiting essential amino acid (FAO/WHO, 1973 reference pattern) with a chemical score of 45 for the protein. The IVPD of cleome seed protein was 72.2% and C-PER was 1.08 relative to the IVPD and C-PER values of 90.0% and 2.50 for the Animal Nutrition Research Council casein.     

Development,acceptability and nutritional value of weaning mixtures

Low cost weaning mixtures were prepared by mixing (i) malted pearl millet (Penicitum typhidium L), roasted amaranth (Amaranthus sp.); roasted green gram (Vigna radiata); jaggery and (ii) malted barley (Dehusked barley); roasted amaranth grain; roasted green gram; jaggery in proportion 60204045 wt/wt and were nutritionally evaluated. Both the blends had a nutrient composition within the range prescribed by the Indian Standard Institute (ISI) for processed weaning foods. The processing of grains resulted in lower levels of phytic acid, polyphenols and saponins and higher in vitro protein digestibility than those of the raw grains used for preparing mixtures. Both the mixtures were acceptable to trained panelists and children.     

Digestibility of protein and amino acids in selected foods as determined by a rat balance method

Values (%) for true digestibility of crude protein and individual amino acids in 20 selected foods were determined by the rat balance (fecal) method. The products were fed as the sole source of protein in diets containing 8% crude protein (N × 6.25). Lowest true protein digestibility values (79–84) were obtained for pinto beans, kidney beans and lentils; intermediate values (89–92) were obtained for chick peas, beef stew, skim milk (over heated), rolled oats, whole wheat cereal, and pea protein concentrate; and highest values (94–100) were obtained for sausage, macaroni-cheese, rice-wheat gluten cereal, skim milk, tuna, soy isolate, peanut butter, chicken frankfurters, beef salami, casein and casein + methionine. In animal foods, peanut butter and soy isolate, the differences between true digestibility of crude protein and most individual amino acids were less than 5%. However, the values for true digestibility of methionine and cystine were up to 44% lower than those of crude protein in pinto beans, kidney beans, lentils, chick peas and pea concentrate. In these legumes, digestibility of crude protein was not a good predictor of digestibility of the limiting amino acids.     

Nutritional quality of the protein in quinoa (Chenopodium quinoa,Willd) seeds

The nutritional quality of protein in quinoa seeds has been determined by amino acid assay and by animal feeding experiments. The amino acid composition of the protein in raw quinoa and washed quinoa show similar pattern. The first limiting amino acids were the aromatic amino acids thyrosine + phenylalanine giving a chemical score of 86 for protein in raw quinoa and 85 for protein in washed quinoa. Threonine was the next limiting amino acid followed by lysine. The amount of lysine and sulfur amino acids (methionine + cystine) was relatively high. In general, the content of essential amino acids in quinoa is higher than in common cereals. The animal experiments showed NPU values of 75.7, BV of 82.6 and TD value of 91.7 for the protein in raw quinoa. Results of the in-vitro enzymatic methods showed that the digestibility of the protein in quinoa is comparable to that of other high quality food proteins. The corresponding experiments carried out with samples of guinoa seeds, which have been processed to remove the saponins, showed that, the saponins do not exert any negative effect on the nutritive quality of the protein.     

The nutritive value of amaranth grain (Amaranthus caudatus)

Digestibility of dietary fibre (DF) and energy of three pale-seeded and one darkseeded variety ofAmaranthus caudatus were studied in balance experiments with growing rats. Effects of processing: popping, toasting and flaking were also examined. The pale seeds contained about 8% of DF and the black seeds about twice as much. The soluble DF fraction made up 33–44% of the total DF (TDF) fraction in the pale-seeded varieties, but only 18% in the black seeds. The monomer sugar composition of the DF was very similar in all products. However, the black seeds were very high in lignin, and DF of the black-seeded products were more resistant to digestion than that of the pale-coloured products. In the pale amaranth products digestible energy (DE) varied between 86 and 91%. In the dark-seeded products DE was lower, and there was a significant negative correlation (r=–0.92) between DE and TDF. Processing of pale seeds had only minor effects on TDF and DE, but increased the proportion of soluble DF and the digestibility of DF in one variety. The food intake tended to be lower in rats fed raw pale seeds compared with those consuming processed products, indicating the presence of heat-labile factors reducing palatability.In conclusion, the pale seeds had a lower content of DF than most cereal grains and the DF was more easily digested. As a source of energy, amaranth grains seem to be comparable to other cereals.     

Nutrient composition and biological evaluation of mesta (Hibiscus sabdariffa) seeds

Two varieties of mesta (Hibiscus sabdariffa) seeds were analysed for their proximate composition. Their protein (18.8–22.3%), fat (19.1–22.8%) and dietary fiber (39.5–42.6%) contents were found to be high. The seeds were found to be a good source of minerals like phosphorus, magnesium and calcium. Their lysine and tryptophan contents were also high. Sulphur containing amino acids were limiting in this seed protein and the chemical score of mesta seed protein was 40 and 57 for AMV-2 and Bhimili-1 varieties respectively. Mesta seed oil is rich in unsaturated fatty acids (70%), of which linoleic acid constituted 44%. Weanling rats were fed with 10% mesta seed protein before and after cooking for 4 weeks. Food intake of animals receiving raw mesta seed diets was significantly lower than those receiving cooked mesta seed diets as well as the casein control diet. Protein and dry matter digestibilities of raw and cooked mesta seed diets were lower than that of casein control diet. Cooking improved the food intake, gain in body weight, dry matter and protein digestibility of mesta seed diets. PER and NPU of cooked mesta seed diets were significantly higher than the corresponding raw diets. These results indicate that cooked mesta seed protein is of relatively good quality.     

Effects of hybrid,environment, oil addition,and microwave wattage on popped popcorn morphology

The objective of this study was to understand what factors influence the formation of different shapes of popped popcorn through the development of statistical models. Microwave popcorn popping was conducted across a range of microwave wattages (750–1240 W) and oil additions (0–30%) using a set of three popcorn hybrids grown in three environments. After popping, expansion volume was measured and the relative proportion of different popped shapes was enumerated by visual characterization of popped flakes, namely: unilateral, bilateral, or multilaterally expanded. The percentage of flake morphologies varied from 1 to 24% unilateral, 20 to 55% bilateral, and 31 to 68% multilateral across all runs. The relative percentage of each shape was influenced by hybrid, growing location, corn:oil ratio, and microwave wattage. The proportion of unilateral flakes was positively correlated to oleic acid in the kernel and negatively correlated to kernel sphericity, while bilateral flakes were positively correlated to dietary fiber in the kernel. Expansion volume was positively correlated to occurrence of bilaterally expanded flakes and negatively correlated to unilateral shape. These data may support the development of new hybrids or varieties of popcorn that produce the most desirable amounts of popped shapes in order to optimize consumer liking or create differentiated products and market new usages for popcorn.     

Relationship between the corneous and floury endosperm content and the popped sorghum quality

Popcorn is a healthy snack suggested by nutritionists. However, some countries in Europe, Asia, and South America have evaluated the use of sorghum as a popped cereal. Therefore, this study aims to evaluate the content of corneous and floury endosperm of sorghum and its influence in the popped sorghum quality. Five red varieties and three white varieties were evaluated. The physical and microstructural characteristics of the raw varieties were evaluated. The correlation matrix showed that physical properties such as the pericarp thickness, the hectoliter weight, and the type of endosperm are crucial to obtain popped sorghum. A high percentage of corneous endosperm and the size distribution of starch granules in the floury endosperm determine the popping ability of sorghum. The analysis of the principal components showed that the Paloma variety was the most suitable to obtain popped sorghum.     

Characterization of Amaranthus cruentus L. seed proteins by 2-DE and LC/MS–MS: Identification and cloning of a novel late embryogenesis-abundant protein

Amaranth is taking great attention as an important cereal crop that could fulfill food requirements for the growing population, especially in developing countries. However, the protein composition of these seeds is not well known yet. We have used the proteomics tools to characterize amaranth seed proteome. About 400 proteins spots were resolved on two-dimensional gel electrophoresis (2-DE) and protein spots were analyzed by LC-MS/MS (liquid chromatography tandem mass spectrometry). Identified proteins were related to stress and defense responses, metabolic, respiratory, and oxide-reduction processes. One abundant spot was identified as a Late Embryogenesis Abundant (LEA) protein and the gene was cloned and characterized. The AcLEA cDNA contains a 418 bp open reading frame (ORF) encoding a polypeptide of 139 amino acids. Bioinformatics analysis showed that AcLEA belongs to LEAs Group 5. Proteomics is a powerful technique that could be used even in non-sequenced organisms such as amaranth. The obtained information reveals that amaranth seed, beyond the classical seed storage proteins, contains proteins related to protection against stress. The identification of these proteins opens the door to the application of new strategies to improve the quality of amaranth production.     

球形花爆裂玉米爆花品质影响因子研究

以国产球形花爆裂玉米佳球105为试材,对影响爆花品质的多种因子进行研究。结果表明,含水量和成熟度是影响膨爆倍数、爆花率、花形及玉米花大小的主要因子,其中,膨爆倍数、花形对水分含量和成熟度反应最为敏感。在含水量13.4%～13.8%范围内膨爆倍数达到27.4～27.5倍,继续增加或降低水分含量则膨爆倍数下降;含水量在13.8%左右时玉米花最大、花形好且球形率较高,继续降低含水量时花形更加圆滑、美观但玉米花变小。成熟度与子粒体积、粒重、爆花率、膨爆倍数、球花率均呈正相关关系,同等重量的子粒,成熟度越高、子粒体积越小,粒重、爆花率、膨爆倍数、球花率越高。