Amaranth as a rich dietary source of β-sitosterol and other phytosterols

The analysis of 4 commonly available amaranth varieties (Amaranthus K343, RRC1011, K433, K432) revealed the presence of all three major phytosterols (beta-sitosterol, campesterol, stigmas-terol) with a total sterol content being several fold higher than those found in other studied plants. Substantial differences in total phytosterol content and beta-sitosterol content were found between the amaranth varieties. The most commonly cultivated amaranth variety in the United States, i.e., Amaranthus K343 was found to possess the highest levels of phytosterols of the varieties tested. The possibility of screening for superior amaranth varieties with various health properties is outlined.     

Growth and lipid metabolism as affected by feeding of hull-less barleys with and without supplemental β-glucanase

Three hull-less barleys, Washonupana (WSNP), Waxbar (WXB), and Bangsa (BGS), were fed to broiler chicks in 21% protein diets containing 0.5% cholesterol in replicate trials. A corn-based diet, with added cholesterol, served as a control. Alternate diets were supplemented with -glucanase (ENZ). -glucan content ranged from 4.9% to 6.1% and soluble dietary fiber (SDF) from 3.6% to 7.5% in the barleys. Data from the two trials were pooled for statistical analysis by the SAS General Linear Models procedure. In body weight gain, chicks fed WSNP — ENZ were lower (P<0.05) than all other treatments. The -glucanase supplement to the WXB and BGS barley tended to improve gains, but the differences were not significant for either barley. Feed to gain ratios were lowest (P<0.0001) for corn fed chicks and lower (P<0.05 toP<0.0001) for those fed the barley+ENZ diets compared to barley –ENZ. Chicks fed barley diets had lower (P<0.05) total serum cholesterol (TSC) and LDL-cholesterol than those fed corn diets, regardless of ENZ supplementation. For chicks on barley –ENZ diets, TSC levels for WSNP, WXB, and BGS were 146, 152, and 142 mg/dl respectively and for chicks on barley +ENZ diets, 218, 200, and 178 mg/dl. LDL-cholesterol levels followed the same trend and there was little difference in serum triglycerides. The BGS+ENZ lowered TSC 30% from the corn control compared to 10.7% and 18% for WSNP+ENZ and WXB+ENZ, suggesting additional hypocholesterolemic factors, possibly tocotrienol and SDF other than 13, 14 -D-glucans.Contribution No. J-2487, Montana Agricultural Experiment Station. This research was supported, in part, by a grant from the Montana Wheat and Barley Committee, Great Falls, MT, U.S.A.     

Changes in carbohydrate and nitrogenous components and amylase activities during germination of grain amaranth

Grain amaranth (Amaranthus hypochondriacus), Yercaud local variety, was soaked overnight and germinated for 192 h taking the soaked grains as the zero time (0 h) sample. The changes in the activities of - and -amylases, starch, sugar, protein and lysine contents during germination are reported. Activity of -amylase was high in the 0 h soaked grains, while -amylase activity was high in 72 h germinated grains. The joint action of the amylases resulted in a decrease of starch content from 0 to 192 h in germinated grains and an increase in total sugars during the initial period of germination.Protein nitrogen was found to decrease from 48 h to 192 h accompanied by an increase in free amino acid and non-protein nitrogen contents. Total lysine content was found to be increased by 31% in 24 h germinated grain amaranth. Protein fractionation of raw, soaked and 24 h germinated grain amaranth showed that the distribution of different types of proteins varied during germination of the grains. An increase of water soluble protein content was noticed in 24 h germinated grains.     

Influence of grain quality,heat, and processing time on the reduction of aflatoxin B1 levels in ‘tuwo’ and ‘ogi’: Two cereal-based products

During the production of tuwo from laboratory-contaminated corn (AFB₁:150 mcg/kg) and sorghum (AFB₁:87.5 mcg/kg) grains, reductions in the aflatoxin-B₁ levels of pastes boiled for 30 min and 60 min were found to be 68.0% and 80.8%, respectively. In the preparation of ogi from contaminated corn and sorghum grains, reductions of about 72.5% and 71.4%, respectively, were obtained after fermentation at ambient conditions. Reconstitution of ogi paste into a porridge (akamu) considerably reduced the AFB level.     

Biochemistry of Fruit Ripening of Guava (Psidium guajava L.): Compositional and Enzymatic Changes

Changes in chemical composition and the activities of hydrolytic enzymes during four different stages of maturity, viz. mature green (MG), color turning (CT), ripe (R), and overripe (OR), have been studied in guava fruits cv. Banarsi Surkha. Chlorophyll content decreased while carotenoid content increased during ripening. Starch content decreased with concomitant increase in alcohol-soluble sugars. Cellulose, hemicellulose, and lignin also decreased up to ripe stage, while pectin continued to decrease up to OR stage. PG (polygalacturonase) and cellulase exhibited progressive increase in activity throughout ripening, whereas pectin methyl esterase (PME) activity increased up to CT stage and decreased at R stage. The activities of alpha-amylase and beta-amylase decreased significantly with ripening. The most notable metabolic changes occurred between MG and CT stage, implying that for improved postharvest handling, guava fruits may be harvested at CT stage.     

Effect of traditional open sun-drying and solar cabinet drying on carotene content and vitamin A activity of green leafy vegetables

Dried green leafy vegetables constitute a major dietary source of provitamin A carotenoids for people living in semi-arid areas of Tanzania. In the present study, eight vegetable varieties commonly consumed in these areas were either traditionally sun-dried or solar-dried, and the amount of provitamin A carotenoids were determined by HPLC. In the fresh blanched leaves, the contents of -carotene, -carotene, 9-cis--carotene and 13-cis--carotene were in the range of 526–917, 12–39, 80–136 and 16–40 g/g dry matter/basis; dmb, respectively. The average amounts of all-trans--carotene in the leaves after blanching, solar drying and open sun-drying were 662, 502 and 353 g/g dmb, respectively, all significantly different from each other (p <0.001). The average amounts of all-trans--carotene were 21, 15 and 8 g/g dmb (p <0.05) and of 9-cis--carotene 101, 82 and 63 g/g dmb (p <0.05) in the blanched, solar-dried and open sun-dried samples, respectively. Estimation of the amount of retinol equivalents provided by the dried vegetables for preparation of an edible portion of 100 g relish showed that solar-dried vegetables contributed more (between 120–275%) than the recommended level of vitamin A, and on average 43% more retinol equivalents than relishes of open sun-dried vegetables.Thus, it is concluded that the amount of provitamin A-carotenes in traditionally treated vegetables were highly reduced by open sun-drying while solar drying resulted in significantly more retention of the carotenes. All-trans--carotene and 9-cis--carotene were similarly affected as all-trans--carotene by the two drying methods. Consumption of a 100 g portion of solar-dried vegetable relish could provide the recommended daily intake of vitamin A.     

Effect of home processing on ascorbic acid and β-carotene content of spinach (Spinacia oleracia) and amaranth (Amaranthus tricolor) leaves

The present investigation was conducted to study the concentration of ascorbic acid and -carotene in spinach and amaranth leaves as affected by various domestic processing and cooking methods which included storage of leaves in polythene bags or without packing for 24 and 48 hours in refrigerator at 5 °C; at 30 °C in polythene bags; drying (sun and oven); blanching (5, 10, 15 min); open pan and pressure cooking. Ascorbic acid content of fresh leaves was 624.1 to 629.0 mg and -carotene content was 35.3 to 53.1 mg/100 g dry weight. The percent loss of ascorbic acid ranged from 1.1 to 6.3 and 55.3 to 65.9 while lower losses (0.0 to 1.3 and 1.5 to 2.1) of -carotene were observed in leaves stored in refrigerator and at 30 °C, respectively. A markedly greater reduction in ascorbic acid and -carotene was observed in dried, blanched and cooked leaves. The study recommended the storage of leaves in refrigerator, drying in oven, blanching for shorter time and cooking in pressure cooker for better retention of these two vitamins.     

α and β-galactosidase activities and oligosaccharide content in peanuts

Thirty-three peanut cultivars were examined for their alpha-1,6 and beta-1,4 galactosidase activities and oligosaccharide contents along with proximate compositions. The average moisture, protein, fat, ash, and carbohydrate contents were: 4.9%, 26.6%, 43.1%, 2.3% and 23.1%, respectively. The corresponding coefficients of variation were: 5.2%, 10.1%, 7.2%, 7.8% and 15.7%, respectively. Raffinose and stachyose contents (%) ranged from 0.05 to 0.12 and 0.31 to 0.61, respectively. The specific activity (micromol product/min/mg protein) of crude preparation of alpha-galactosidase for the 33 cultivars ranged from 1.096 to 2.784 for the non-germinated seeds and from not being detected in some samples up to 2.432 for the germinated seeds; the mean values for non-germinated and germinated seeds were: 1.781 and 1.410, respectively. The specific activity of beta-galactosidase ranged from 0.101 to 1.727 in the non-germinated seeds and from not being detected in some samples up to 0.898 in the germinated seeds. Germination decreased the activity of both galactosidases significantly (p < or = 0.05).     

Studies on the influence of temperature,relative humidity and microenvironment on the natural fermentation of African oil bean seeds to ‘Ugba’

Studies on the enhancement of the traditional production of Ugba (a protein-rich fermented food) from African oil bean seeds were undertaken by fermenting the bean seeds at different temperatures, relative humidities (RH) and microenvironments. Fermentation was monitored by pH, texture, amino-nitrogen content and the viable cell count of the substrate. The 40 °C, 98% RH or the 130 m high density polyethylene (HDPE) treatment increased the fermentation microflora from ca. 106 CFU/g to ca. 108 CFU/g with high initial changes in pH (5.8–ca. 7.9) and texture (2.0 kg/cm2 to between 1.4 kg/cm2 and 0.9 kg/cm2) in 24 hours. Products with amino-nitrogen contents of between 12.00 mg N/100 g dry matter and 14.00 mg N/100 g dry matter were obtained in 3 days. The cell count of the 30 °C, 80% RH or 70 m treatment increased from 106 CFU/g to ca. 107 CFU/g and the pH increased from 5.8 to about 6.7 with a coincident decrease in the texture value from 2.0 kg/cm2 to about 1.7 kg/cm2 in 24 hours. Products with amino-nitrogen contents between 15.00 mg N/100 g dry matter and 19.2 mg N/100 g dry matter were obtained after 3 days. Changes in the fermentation indicators were not significant at p0.05 (pH and texture) and at p0.01 (amino-nitrogen) after 3 days for the 25 °C, 59.9% RH or 50 m low density polyethylene (LDPE) treatment. Products of fermentation at the combined optimal conditions (80% RH, 35 °C and 70 m HDPE) compared very well with the traditionally fermented products in terms of pH, texture and amino-nitrogen content.     

Utilization of β-carotene fromSpirulina platensis by rats

The availability of -carotene from Spirulina as compared to standard all trans -carotene was studied by the liver and kidney vitamin A storage method. After 21 days of vitamin A depletion, the rats were repleted with -carotene from Spirulina and a standard source at two dietary levels (60 and 120 µg/day) for a 10 day period. At lower levels, the liver storage levels of vitamin A and the percent of -carotene absorption were comparable to those of the standard. At higher levels both these parameters of the Spirulina fed group were significantly (P<0.01) inferior to the standard source fed group. However, the Spirulina fed group showed better (P<0.05) growth than the standard fed group did at both low and high levels of feeding.     

Comments on the importance of green vegetables

Green, especially leafy, vegetables are widely underesteemed because few horiticultural research institutes publish figures demonstrating that they can give unusually large annual yields of edible dry matter, including protein and carotene (provitamin A). It is also not realised that they supply many communities with as much protein as is supplied by fish, and that more communities used to eat them on that scale. Before leafy vegetables gain proper nutritional attention it will be necessary to convince consumers that they are not merely sources of vitamin C and minerals, or decorative adjuncts to a meal. It will also be necessary to persuade those who compile dietary and production statistics to separate leafy vegetables from other horticultural products which, although they may yield more profit per hectare, are of much less nutritive value.     

Alpha amylase inhibitors in sorghum (Sorghum bicolor)

Forty varieties of sorghum grown locally and four cereals were screened for inhibitory activity against human salivary amylase. Three varieties of sorghum (IS-22422, Nagi Monadi and Ngd Marnm) had maximum inhibitory activity of 124 units. Among the cereals rice had the lowest inhibitory activity. Amylase inhibitory activity was lost on germination and heating the seeds.     

Changes in β-carotene and ascorbic acid content of fresh amaranth and fenugreek leaves during storage by low cost technique

Leafy vegetables are highly perishable and their shelf life depends on duration and conditions of storage. A low cost storage structure was used to extend the shelf life of amaranth and fenugreek and their quality was evaluated on the basis of retention of -carotene, ascorbic acid and chlorophyll during storage. Losses of -carotene ranged from 46.5 to 85.0% for amaranth and 24.0 to 73.0% for fenugreek depending on duration and conditions of storage. Similarly ascorbic acid retention varied from 9–32% for amaranth and 23–80% for fenugreek. Results showed that the degradation of quality parameters was faster at ambient conditions and packaging of leaves in low density polyethylene bags was beneficial in improving shelf life and nutritive value. Low cost storage structure was similar to low temperature storage for retention of -carotene, ascorbic acid, chlorophyll content and enhancement of shelf life.     

Bioavailability trials of β-carotene from fresh and dehydrated drumstick leaves (Moringa oleifera) in a rat model

Male albino rats (Charles Foster, n = 40) were fed a synthetic diet deficient in vitamin A for 4 weeks. Six rats died during the depletion period. Of the 34 surviving, 5 rats were continued on the vitamin A deficient diet for 4 more weeks and 24 were repleted with vitamin A (4000 IU/kg diet) in the form of vitamin A acetate (group A, n = 8), fresh drumstick leaves (group B, n = 8) or dehydrated drumstick leaves (group C, n = 8) for 4 weeks. The remaining 10 rats were continued on the vitamin A adequate diet for 4 (n = 5) and 8 weeks, respectively (n = 5). A marked reduction in food intake, body weight, accompanied by clinical signs of vitamin A deficiency and a decline in serum vitamin A (29.2 to 19.1 g/dL) and liver vitamin A (3.7 to 2.0 g/dL) were seen at the end of 4 weeks of feeding a vitamin A deficient diet. On repletion significant improvements in clinical signs, food intake and body weights were noted in the three groups compared to the baseline (n = 5) and at the end of 4 weeks of depletion. The gain in body weight was highest for the group repleted with dehydrated drumstick leaves. Among the repleted groups, the serum vitamin A was highest for group A (34.7 g/dL) given synthetic vitamin A, compared to group B (25.8 g/dL) and group C (28.2 g/dL) given drumstick leaves. All these were significantly higher than the serum vitamin A values seen at the end of 4 weeks of depletion (19.1 g/dL). A significant improvement was also observed in the liver retinol levels on repletion for 4 weeks in the three groups, compared to the vitamin A depleted rats. These results imply that -carotene from drumstick leaves was effective in overcoming vitamin A deficiency although serum vitamin A levels remained somewhat lower compared to the group repleted with vitamin A acetate. In terms of growth parameters, the fresh and dehydrated drumstick leaves were better than the synthetic vitamin A. It is therefore concluded that in the developing countries like India, sources of vitamin A such as drumstick leaves are valuable in overcoming the problem of vitamin A deficiency.     

Gibberellic acid (GA3) induced changes in proanthocyanidins and malt quality of two and six-row husked barleys

Analysis of husked barleys for proanthocyanidins and malt qualityattributes has shown that not a single variety is free ofproanthocyanidins. The proanthocyanidins in barley grains variedfrom 3.85 to 4.94 mg/g as catechin equivalent. The concentrationof proanthocyanidins decreased, while total soluble sugars, reducingsugars, diastatic power and -amylase activity increasedduring maltings as well as with exogenous gibberellic acid (GA₃)application. Alfa 93 (two-row) and RD2560 (six-row) varietiesappeared to be superior for malting and brewing purposes on thebasis of proanthocyanidins, total phenols, diastatic power and-amylase activity. It is suggested that exogenous applicationof GA₃ at 15 ppm may be useful for producing good quality maltfrom barley grains.     

Food potentials of some unconventional oilseeds grown in Nigeria — A brief review

A brief review of literature on kernels ofCitrullus andCucumeropsis (egusi melon) species,Telfairia occidentalis (fluted pumpkin),Lagenaria (gourd) species all of Cucurbitaceae family and other oilseeds such asPentaclethra macrophylla (African oil bean),Parkia spp. (African locust bean) both of Mimosaceae family andButyrospermum paradoxum (shea butter) of Sapotaceae family which are grown and widely used as food in Nigeria is presented. The kernels of species of Cucurbitaceae form the bulk of unconventional oilseeds used for food in Nigeria. The nutritional value of some of the kernels and the physicochemical properties and storage stability of the oils obtained from them are discussed. The various consumable forms in which they exist are also described. The problems and prospects of these neglected oilseeds in Nigeria are highlighted.     

Red palm oil as a source of β-carotene for combating vitamin A deficiency

Twenty four school children of 7–9 years of age were divided into two groups of six boys and six girls each. One group was given a daily supplement of Suji halwa, a sweet snack made with semolina and red palm oil, supplying 2400 µg of -carotene and the second group was the control group which was given 600 µg of oral vitamin A palmitate, for 60 days. Vitamin A status before and after supplementation was assessed by the Modified Relative Dose Response Assay (MRDR). Results indicated that serum vitamin A levels increased from the basal level of 0.86±0.13 µmol/l to 1.89±0.23 µmol/l in the Red Palmoil (RPO) group and from 0.74±0.09 to 1.94±0.21 µmol/l in the control vitamin A group. Dehydroretinol/Retinol (DR/R) ratio decreased from 0.073±0.025 to 0.023±0.004 in the RPO group and from 0.090±0.023 to 0.023±0.004 in the vitamin A group, indicating liver saturation with vitamin A after feeding RPO snacks, comparable to synthetic vitamin A. This study indicates that RPO is an efficient source of -carotene which is found to be bioavailable in all the subjects tested, hence it can be used for supplementary feeding programmes to combat vitamin A deficiency in target population.     

Fatty acid and amino acid composition of groundnut mutants

Groundnut mutants TG-8, TG-9, TG-17 and TG-18 induced by -irradiation differed in fatty acid composition from their parent Spanish Improved. All the mutants had lower linoleic and higher oleic than Spanish Improved. TG-18 had lower oleic and higher linoleic as compared with TG-8, TG-9 and TG-17. Palmitic acid in TG-18 and Spanish Improved was higher than other mutants. Oil stability as judged by oleic to linoleic ratio was substantially higher for mutants as compared with their parent.Amino acid composition of groundnut mutant proteins differed from Spanish Improved. In general mutants had higher contents of lysine, histidine, proline, phenylalanine and tryptophan and lower contents of threonine, serine and methionine. The first limiting amino acid was tryptophan in Spanish Improved, threonine in TG-8, TG-9 and TG-17 and Valine in TG-18. Essential amino acid contents for all except methionine, valine and threonine per grain flour were higher in all the mutants as compared with their parent.     

Protein quality and digestibility of new high-lysine barley varieties in growing rats

Four new high-lysine barley mutants, the variety Lysimax, with the high-lysine genelys3a and the mutants mother variety Sultan were grown in a field trial in 1993 at Risø, Denmark. Mutants 609, 1242, 1385 and 1405 yielded in the range of 89 to 98 percent and cv Lysimax yielded 102 percent of cv Sultan (100 percent). One-thousand kernel weights for the mutants were in the range of 87 to 97 percent and cv Lysimax 83 percent of cv Sultan (100 percent). Protein contents of the mutants were slightly higher, in the range of 13.2 to 13.6 percent, than of cv Sultan (13.1 percent) and Lysimax which had a protein content of 12.6 percent. Fat content was higher in Lysimax and in the mutants except for mutant 1385 than in cv Sultan while dietary fibre contents of the barleys were similar. The levels of -glucans and starch were usually lower in Lysimax and in the mutants. The highest lysine levels: 4.6, 4.0 and 3.7 g/16 g N occurred in cv Lysimax and mutants 609 and 1405 compared to 3.3, 3.3 and 3.2 for cv Sultan and mutants 1242 and 1385, respectively. Mutants 609 and 1405 and cv Lysimax also had higher levels of threonine, histidine and valine. The increased lysine contents resulted in large, at most 20 percent, increases in biological value; 88.8, 81.7 and 78.3 percent for cv Lysimax and mutants 609 and 1405 compared to 74.2 percent for cv Sultan. True protein digestibilities and energy digestibilities were slightly lower in Lysimax than in Sultan, 5.3 and 4.3 percentage units, respectively. It is concluded that the development of high-lysine barley varieties is very beneficial for meeting the requirements of indispensable amino acids for humans and monogastric animals. In addition, nitrogen excretion into the environment is drastically reduced due to the higher biological values of the mutants.     

Factors affecting β carotene destruction in moist preserved leaf protein

Leaves are, and will probably remain, an important dietary source of carotene (provitamin A). There is enough of it in extracted leaf protein (LP) to make that a useful source. carotene is rapidly destroyed when LP, especially from young leaves, is preserved with salt. Destruction can be partly prevented by avoiding contamination with iron during preparation, by coagulating LP by heating rather than acidification, and by treatment with chelating agents. The unsaturated fatty acids in leaf lipids seem not to be involved in the destruction.