Chemical composition and some plant characteristics in relation to quality of some promising cultivars of carrot (Daucus carota L.)

Twenty three cultivars of carrot (Daucus carota L.) roots consisting of fifteen local and eight exotic cultivars were analysed for various chemical constituents including dry matter, total soluble solids (TSS), -carotene, total and reducing sugars, phenolics, phosphorus, zinc, manganese, copper, iron, sodium potassium and ash. In addition other characteristics such as days to maturity, root weight and length, flesh thickness, core diameter, number of forked and cracked roots per plot have been studied. Yellow carrots were found to have maximum root length, water soluble carbohydrates and minimum -carotene content. The exotic cultivars were found to have higher TSS content than the local cultivars, while the latter cultivars had higher mineral contents than the former. However, on the average, dry matter content, total water soluble sugars, reducing and non-reducing sugars were found to be greater in exotic cultivars than in local ones, but -carotene, phenols and phosphorus contents were greater in local cultivars. A significant positive correlation between -carotene content, ash percentage and days to maturity was observed. A wide variation in chemical constituents and plant characteristics was observed indicating a high genetic variability in the material under study.     

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.     

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 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.     

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.     

Reversed phase HPLC analysis of α- and β-carotene from selected raw and cooked vegetables

Traditional AOAC colorimetric procedures for carotenoid analysis are known to lack specificity and accuracy. Newer HPLC methods provide the investigator with a more precise tool for carotenoid quantification in foods and tissues. In the present studies, reverse phase HPLC was utilized to evaluate the - and -carotene content in raw and cooked leaves of lettuce, spinach and winged bean as well as in the carrot root. The vegetables were boiled or steamed and the true retention of - and -carotene in the cooked products was determined. Boiling for 30 minutes resulted in a 53 and 40% loss of -carotene from lettuce and carrots, respectively. Full retention or even an increase in -carotene content in boiled winged bean leaves and spinach was noted. Steaming resulted in very good retention of - and - carotene in all vegetables (83–139% retention). Thus, although cooking procedures (especially boiling) may result in oxidative loss of carotenoids in some vegetables, heat treatment increases the chemical extractability of - and -carotene in others. The presence of carotenoproteins in some vegetables may effect the heat stability of extractability of - and - carotene.     

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 different levels of nitrogen and farmyard manure on yield and quality of spinach (Spinacea oleracea L.)

The effect of different levels of nitrogen N₀(0kg/ha), N₁(30 kg/ha), N₂ (60 kg/ha), and N₃ (90 kg/ha) and farmyard manure F₀ (0 tonnes/ha), F₁ (10 tonnes/ha), and F₂ (20 tonnes/ha) on the yield and nutrient composition of spinach and its uptake was investigated on a sandy loam soil. Yield; phosphorus, iron, manganese, zinc, and copper uptakes; and ascorbic acid content increased with the application of both the inorganic nitrogen fertilizer and the farmyard manure, with a maximum at the N₃F₂ level, i.e. at 90 kg N/ha with 20 tonnes FYM/ha. However, the contents of protein, -carotene, and reducing sugars were maximum at the highest dose of nitrogen without the application of farmyard manure.     

Nutritional value of some non-conventional plant foods of India

Thirteen non-conventional foods including fruits, leaves and grains consumed in various parts of the Indian subcontinent were analysed for their nutritional value. Khejri beans (Prsopsis cineria), Pinju (Capparis decidua) and Kachri (Cucumis species) contained considerable amounts of protein (15–18%). Kachri was rich in fat (13%). Bhakri (Tribulus terristris), Gullar (Ficus glomerata) and Peehl (Salvadora oleoides) were found to be rich sources of calcium; Gullar contained about 15 times the amount of calcium present in wheat. Phosphorus content of Santhi (Boernavia diffusa), Khejri beans, Bhakri, Pinju and Lehsora (Cordia dichotoma) were noticeable. Zinc was present in high amounts in Peepalbanti (Ficus religiosa) and Gullar; as was iron in Santhi and Bhakri and manganese in Santhi. Besides iron, zinc and calcium, Pinju contained appreciable amounts of -carotene and vitamin C. However, Santhi contained high amounts of oxalic acid.     

Proximate composition and mineral content of two edible species of Cnidoscolus (tree spinach)

Proximate composition and mineral content of raw and cooked leaves of two edible tree spinach species (Cnidoscolus chayamansa and C. aconitifolius), known locally as chaya, were determined and compared with that of a traditional green vegetable, spinach (Spinicia oleraceae). Results of the study indicated that the edible leafy parts of the two chaya species contained significantly (p<0.05) greater amounts of crude protein, crude fiber, Ca, K, Fe, ascorbic acid and -carotene than the spinach leaf. However, no significant (p>0.05) differences were found in nutritional composition and mineral content between the chaya species, except minor differences in the relative composition of fatty acids, protein and amino acids. Cooking of chaya leaves slightly reduced nutritional composition of both chaya species. Cooking is essential prior to consumption to inactivate the toxic hydrocyanic glycosides present in chaya leaves. Based on the results of this study, the edible chaya leaves may be good dietary sources of minerals (Ca, K and Fe) and vitamins (ascorbic acid and -carotene).     

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.     

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.     

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.     

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.     

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.     

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.     

On determination of chitin content in mushrooms

Nitrogen compounds constitute the greatest proportion of the dry weight of mushrooms. These nitrogen compounds are partly protein and partly non-protein. A modified Heneberg-Stohman's method was used to separate non-protein from protein nitrogen, as well as to determine raw fiber content in mushrooms, since the methods used previously for this purpose are time-consuming and complicated. Elemental analysis of crude fiber was performed to confirm the uniformity of isolated products. The content of total crude fiber (fungin) and the proportion of chitin and cellulose in it were determined. The chitin content of 15 species of field grown edible mushrooms was in the range of 1.87–6.93% of total dry mass and 34.51–67.72% of isolated fungin.     

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.