In Vitro Accessibility and Intake of β-Carotene From Cooked Green Leafy Vegetables and Their Estimated Contribution to Vitamin A Requirements

Provitamin A carotenoids from green leafy vegetables constitute a major dietary source of vitamin A in Tanzania. The efficiency of different vegetable preparations in contributing to the daily safe intake level of vitamin A for children was evaluated in the present study. The amount of bioaccessible (available for absorption) all-trans--carotene from green leafy vegetable dishes prepared either traditionally in households or with an improved method was estimated by an in vitro digestion method that simulates human digestion. The median vegetable portion size consumed by 34 children (2--12 years old) in the surveyed households was determined by weighing. The amount of all-trans--carotene available for absorption from the same type of vegetables cooked without oil by traditional or a modified method ranged from 5 to 12% and 4 to 15%, respectively. Vegetables cooked with modified method with oil had 2–5 times higher amount of in vitro accessible all-trans--carotene than vegetables cooked without oil. A median portion (84 g) of such a relish then provided 88–477% of the daily safe intake level of vitamin A, while portions cooked without oil only provided between 23 and 46%. In this study, a wide variation in all-trans--carotene content and bioaccessibility among studied green leaves was obtained. Still, to supply daily safe intake level of vitamin A for children from a median vegetable relish portion it is necessary to add oil in the preparation.     

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.     

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.     

Levels of β-carotene and effects of processing on selected fruits and vegetables of the arid zone of India

Some locally available fruits and vegetables of the arid zone of Rajasthanwere analyzed for their -carotene content; the selected fruits and vegetables were: Dansra (Rhus myserensis), Kachri (Cucumis collosus), fruit Kachri (Cucumis collosus), Kair (Capparisdecidua) and Sanghri (Prosopis cineriria). The -carotene contents of the samples were estimated in fresh and various processed states (blanched, dried and roasted). The results showed the heat lability of -carotene. Among the samples, kair was found to be the richest source of -carotene. Variety, too, had an impact on the content of this fat soluble vitamin.     

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.     

Effect of alkaline treatment (‘akanwu’) and supplementary value of corn or crayfish on the protein quality of breadfruit (Treculia Africana)

The effect of treatment and supplementary value of corn (C) or crayfish (CR) on the protein quality of breadfruit (Treculia Africana) flours were studied in eighteen young rats. The 7030 or 701515 (Protein basis) combinations of breadfruit flours and corn or crayfish or both provided 1.6g N/100 g diet for the 35 day study. The addition of akanwu to the cooking water reduced cooking time and crude protein and saved fuel. The addition of akanwu and replacement of CR with C was not beneficial as judged by the parameters tested except for the wt. gain and PER. On the other hand, when crayfish was the only source of supplementary protein (30%) to breadfruit cooked without akanwu there were increases in all parameters tested over those with added akanwu except for the N intake, wt. gain, and PER.These results appear to suggest that addition of akanwu to TA was detrimental to its protein utilization and that TA appears to be an economic source of N in areas where it is a staple. Based on the results of this study, one would suggest that the use of akanwu as a tenderizer should be seriously looked into before further use.     

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.     

Some preliminary observations on treatments which increase and decrease the stability of β-carotene in preserved,moist leaf protein

-carotene in leaf protein extracted from some species is destroyed in a few days when incubated with salt as a preservative. Its shelf-life can be greatly extended by pretreatment with oxalate, ascorbate mercaptans, phenolic substances, extracts made from leaves in which carotene is more stable, and by tight compaction. Treatment with alum reverses the protective effect of these chemical pretreatments, it also increases the lability of carotene in leaf protein extracted from species which usually give a relatively stable product. In these preparations of leaf protein, which were heated to 90 °C during preparation, carotene is only partially extractable into some solvents which are miscible with water. It seems therefore to be present in more than one state, but differences in extractability could not be correlated with differences in lability.     

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.     

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.     

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.     

Retention of quality characteristics of dehydrated green leaves during storage

Green leafy vegetables are the most underexploited class of vegetablesdespite high nutritional value. Reports on nutritional composition andstorage of some of the fresh leaves are available but the storage behaviorof dehydrated leaves apparently has not been studied. Therefore, in thepresent study, two green leafy vegetables, savoy beets (Beta vulgarisvar. bengalensis) and fenugreek (Trigonella foenumgraecum) were dehydrated in a low temperature drier and stored for9 months under ambient and cold stored conditions after packaging insingle or double layers of high density polyethylene film (200 gauge). Thequality was determined on the basis of retention of -carotene,ascorbic acid and chlorophyll, and the extent of browning during storage.Retention of these quality characteristics depended on the crop and storageconditions. Double packed and cold stored samples of fenugreek retained67% -carotene, whereas savoy beet leaves retained only 57% ofthe initial -carotene under similar conditions. Similarly, higherretention of ascorbic acid and chlorophyll, and lower browning wasobserved in double packed, cold stored samples. Results indicated theefficacy of double packed and cold stored samples over other combinations.     

Nutritional composition of selected green leafy vegetables,herbs and carrots

Six green leafy vegetables and herbs – spinach, amaranth, bengal gram, cauliflower, mint, coriander and carrots – were analyzed for moisture, protein,ascorbic acid, -carotene, total iron, ionizable iron (as % of total iron) in vitro iron (% of total iron), copper, manganese and zinc. Moisture content of the leaves and carrots varied from 75.1 percent (bengal gram) to 95.4 percent (carrot) and protein from 9.83 percent (carrots) to 30.9 (mint) percent. Ascorbic acid, -carotene, total iron and ionizable iron contents were at a maximum in case of bengal gram leaves whereas level of ionizable iron and in vitro iron as a percent of total iron was highest in carrots. Copper, manganese and zinc contents were maximum in spinach.     

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.     

A study to determine an equation of enveloping curve for regional flood peaks by maximum rainfall data

In this paper, Creagers equation and Groups equation are algebraically examined to determine an equation of an enveloping curve for regional flood peaks from the viewpoint of the curve profile. The applicability of a small drainage area with little observed data on flood peak discharge was examined in comparison to specific flood peak discharge calculated by a rational formula using data of maximum rainfall. In the algebraical consideration, the Creagers equation had an extreme value at a drainage area A=1.0 km², and the specific flood peak discharge became a maximum. Flood peak discharge calculated by Groups equation had an extreme value at a drainage area A=6,568 km², and it became a maximum. Except for Hokkaido, in catchment areas not exceeding 1,178 km², Groups curve q _K was closer to the curve q _DAD of specific flood discharge than Creagers curve qc. From the above research results, the Groups equation is applicability better than the Creagers equation, as the drainage area A is 1,178 km² or less.     

Oat β-glucan-amylodextrins: Preliminary preparations and biological properties

Amylodextrins with soluble -glucan contents from 1 to 10% were prepared from oats and the hypocholesterolemic properties of the latter were evaluated. The products are called OATRIM and can lower blood cholesterol by replacing animal fats rich in cholesterol in food products and, possibly, by the action of -glucan in the body after consumption. In the chick model, decreased total blood cholesterol also resulted in increases of HDL cholesterol and decreases of LDL cholesterol. Processing conditions were found that gave the maximum amount of -glucan and desirable fat-replacement qualities with the least amount of color and flavor.The mention of firm names or trade products does not imply that they are endorsed or recommended by the US Department of Agriculture over other firms or similar products not mentioned.     

Hypolipidemic effect of coriander seeds (Coriandrum sativum): mechanism of action

The effect of the administration of coriander seeds (Coriandrum sativum) on the metabolism of lipids was studied in rats fed a high fat diet with added cholesterol. The spice had a significant hypolipidemic action. The levels of total cholesterol and triglycerides decreased significantly in the tissues of the animals of the experimental group which received coriander seeds. Significant increases in -hydroxy, -methyl glutaryl CoA reductase and plasma lecithin cholesterol acyl transferase activity were noted in the experimental group. The level of LDL + VLDL cholesterol decreased while that of HDL cholesterol increased in the experimental group compared to the control group. The increased activity of plasma LCAT, enhanced hepatic bile acid synthesis and the increased degradation of cholesterol to fecal bile acids and neutral sterols appeared to account for its hypocholesterolemic effect.     

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.     

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.     

Development and Acceptability of a Ready-to-Eat Β-Carotene Rich,Maize Based Supplementary Product

Low cost supplementary products using maize were developed and made using extrusion. -carotene rich sources like curry leaf, carrot, red palm oil were used at different level to increase vitamin A precursor Levels and, therefore, vitamin A. Incorporation of curry leaf powder and carrot powder at 30 percent level and 30:70 blend of red palm oil and groundnut oil were found to be more acceptable than the products made with other levels. These products were tasted for acceptability by preschool children and were analysed for energy, protein, fat and -carotene contents. The control, fresh and stored supplementary products contained 1.707, 1.922, 1.919 MJ, 11.0, 11.6, 10.36 g protein, 10.2, 10.4, 9.64 g fat, 0, 7.37,6.72 mg -carotene per 100g, respectively. The loss of -carotene in processing and storage of curry leaf and carrot supplemented products was 13.69, 6.25 and 20.24, 8.06 percent, respectively.