Concentration of selected heavy metals in spices,dry fruits and plant nuts

Different spices, dry fruits and plant nuts commonly consumed in Pakistan were assayed for the heavy metals cadmium, lead, copper, zinc, iron and manganese by the potentiometric stripping analysis and AA spectrophotometry. The results revealed wide variation in heavy metal content among different biological materials. Mixed spices generally exhibited higher value for trace metals specially lead (6.6–9.2 µg/g), cadmium (0.65–1.34 µg/g), iron (142.3–285.0 µg/g) and zinc (64.2–65.8 µg/g). Dry fruits contained relatively lesser amounts of heavy metals than plant nuts. Almonds contained higher levels of lead (1.02 µg/g) and cadmium (0.24 µg/g) than other nuts and dry fruits.     

Evaluation of the selenium and chromium content of plant foods

In the present study the selenium and chromium content of different plant foods such as fruits, greens, flowers, vegetables, dried fruits, spices, condiments, cereals and pulses were analysed. The selenium values for cereals indehiscent vegetables, root vegetables, stem vegetables, pulses, fleshy vegetables, greens, fleshy fruits, condiment seeds, spices and dried fruits ranged between 24.2–32.16, 2.4–18.9, 2.8–21.5, 3.0–32, 48.7–92.5, 1.25–9.5, 3.0–8.2, 2.0–9.4, 6.2–66.2, 6.2–17.5 and 3.5–16.8 g/100 g respectively. The chromium values for the same ranged between 48.2–52.6, 31.0–45, 21.2–25.7, 23.7–62.8, 15.0–43.5, 20.4–65, 14.2–42.1, 14.25–46.7, 58.4–150 and 96–168 g/100 g respectively. Thus dried fruits have the highest chromium content and pulses the highest selenium content.     

The toxicants and phosphorus content of some Nigerian vegetables

The oxalate, hydrocyanic acid, phytic acid and phosphorus contents of twelve leafy vegetables were determined. The values ranged from 47.7–194.3 mg/100 g DM, 4.32–23.8 mg/100 g DM, 90–260 mg/100 g DM and 215–1110 mg/100 g DM, respectively. The ratio of phytic acid to phosphorus ranged from 13.9–90.7. The leaves contained low levels of hydrocyanic acid, while the oxalate, phytic acid and phosphorus contents were high. The results are discussed in terms of their clinical implications and nutritive values.     

Ascorbic acid content of some Nigerian local fruits and vegetables

Plant Foods for Human Nutrition - Ascorbic acid contents of some common local fruits and vegetables was determined. The ascorbic acid contents of the fruits ranged from 21.8 to 98.0 mg per 100 g...     

Total and Soluble Oxalate Content of Some Indian Spices

Spices, such as cinnamon, cloves, cardamom, garlic, ginger, cumin, coriander and turmeric are used all over the world as flavouring and colouring ingredients in Indian foods. Previous studies have shown that spices contain variable amounts of total oxalates but there are few reports of soluble oxalate contents. In this study, the total, soluble and insoluble oxalate contents of ten different spices commonly used in Indian cuisine were measured. Total oxalate content ranged from 194 (nutmeg) to 4,014 (green cardamom) mg/100?g DM, while the soluble oxalate contents ranged from 41 (nutmeg) to 3,977 (green cardamom) mg/100?g DM. Overall, the percentage of soluble oxalate content of the spices ranged from 4.7 to 99.1% of the total oxalate content which suggests that some spices present no risk to people liable to kidney stone formation, while other spices can supply significant amounts of soluble oxalates and therefore should be used in moderation.     

Common Indian spices: Nutrient composition,consumption and contribution to dietary value

Nutrient composition of eight commonly consumed spices of South India was analysed. Spices analysed were red chillies (Capsicum annum), black pepper (Piper nigrum), coriander seeds (Coriandrum sativum), cumin seeds (Cuminum cyminum), garlic (Allium sativum), asafoetida (Ferula foetida), dry ginger (Zingiber officinale) and ajowan (Carum copticum). The nutrients analysed were proximate principles, minerals, starch, sugars, dietary fibre components, tannins, phytic acid, enzyme inhibitors and amino acids. Dry ginger, ajowan and asafoetida had high calcium (1.0–1.5%) and iron (54–62 mg/100 g) levels. The tannin content of spices was also high (0.9–1.3% DM). Dietary fibre ranged from 14–53%. Spices had appreciable amounts of essential amino acids like lysine and threonine. A survey revealed the average per capita consumption of spices to be 9.54 g and at that level, the nutrient contribution from spices ranged from 1.2 to 7.9% of an average adult Indian male's requirement for different nutrients.     

Chemical evaluation of some important varieties of onion (Allium cepa L.)

Five white and seven red varieties of onion were analysed for dry matter, carbohydrates, total phenols, coloring matter, lachrymatory factor and pyruvic acid content. Percent dry matter varied from 10.66 to 14.80. Total water soluble sugars, reducing sugars and total phenols ranged from 41.50 to 74.00, 12.00 to 22.25, and 1.75 to 2.95 percent (on a dry wt basis), respectively. The lachrymatory factor and pyruvic acid content ranged from 8.00 to 27.25 mg/100g and 6.18 to 13.27 micro moles/g respectively on a fresh wt basis. Red varieties contained a higher phenolic content than white ones. Varieties with higher phenolic content also had a greater amount of coloring matter in the dehydrated onions. The variety Punjab-48 was considered to be most suitable for dehydration purposes.     

Mineral composition of non-conventional leafy vegetables

Six non-conventional leafy vegetables consumed largely by the rural populace of Nigeria were analyzed for mineral composition. Mineral contents appeared to be dependent on the type of vegetables. Amaranthus spinosus and Adansonia digitata leaves contained the highest level of iron (38.4 mg/100 g and 30.6 mg/100 g dw, respectively). These values are low compared to those for common Nigerian vegetables but higher than those for other food sources. All the vegetables contained high levels of calcium compared to common vegetables, thus they could be a rich source of this mineral. Microelement content of the leaves varied appreciably. Zinc content was highest in Moringa oleifera, Adansonia digitata and Cassia tora leaves (25.5 mg/100 g, 22.4 mg/100 g and 20.9 mg/100 g dw, respectively) while the manganese content was comparatively higher in Colocasia esculenta. The concentrations of the mineral elements in the vegetables per serving portion are presented and these values indicate that the local vegetables could be valuable and important contributors in the diets of the rural and urban people of Nigeria. The mean daily intake of P, Mg, Ca, Fe, Cu and Zn were lower than their recommended dietary allowances (RDAs). However, the manganese daily intake was found not to differ significantly ( p = 0.05) from the RDA value.     

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.     

Effect of blanching on the content of antinutritional factors in selected vegetables

The effect of blanching on the antinutritional content was studied in cabbage, turnip, collard, sweetpotato and peanut leaves. All the vegetables contained various amounts of phytic acid, tannic acid and/or oxalic acid. Tannic acid was found in largest amounts ranging from 1266.00 mg/100 g in cabbage to 491.00 mg/100 g in sweetpotato. Phytic acid content ranged from 0.31 mg/100 g in sweetpotato to 3.97 mg/100 g in collard. Oxalic acid was in trace amounts in cabbage and turnip; but high concentrations were found in sweetpotato (469.67 mg/100 g) and peanut greens (407.00 mg/100 g). Levels of both tannic acid and phytic acid were significantly (p<0.05) reduced by conventional and microwave blanching methods while oxalic acid levels were not significantly (p<0.05) reduced in most of the treatments by either of the blanching methods. In general, blanching is recommended as an effective method for reducing the antinutritional factors in green vegetables, however, further investigation on the heating times for both conventional and microwave blanching methods has been suggested.     

Identification and nutrient composition of indigenous vegetables of Tanzania

Thirty types of indigenous vegetables commonly utilized in rural areas of Tanzania were collected, identified and their nutrient compositions analyzed. High values up to 249.6, 266 and 7.7 mg/100 g of vitamin C, calcium and iron, respectively, were recorded. Protein content ranged from 0.6 to 5.0 and fat content 0.1 to 1.0 percent. Generally most of the vegetables were preferred by 50 to 90 percent of the persons surveyed.     

Nutritional and toxic factors in selected wild edible plants

Nutritional (ascorbic acid, dehydroascorbic acid and carotenes); antinutritional and toxic components (oxalic acid, nitrate and erucic acid) were determined in sixteen popular species of wild edible plants which are collected for human consumption in southeast Spain. Ascorbic+dehydroascorbic acids contents were very high in several species, especially in Chenopodium album L. (155 mg/100 g). Carotenoid content ranged from 4.2 mg/100 g (Stellaria media Villars) to 15.4 mg/100 g (Amaranthus viridis L.). A range of values was found for oxalic acid from absence to 1100 mg/100 g of plant material. Nitrate contents ranged from 47 mg/100 g ( Salicornia europaea L.) to 597 mg/100 g (Amaranthus viridis L.). Low amounts of erucic acid were found in the Cruciferae family (Sisymbrium irio L. 1.73%; Cardaria draba L. 1.23%) and Plantago major L. 3.45%.     

Protein,calcium, iron,and amino acid content of selected wild and domesticated cultivars of finger millet

Two wild and eight domesticated cultivars of finger millet were analyzed to determine their proximate composition and calcium, iron, and amino acid content. Wide variations were observed in the protein (mean values ranged from 7.5 to 11.7%), calcium (376 to 515 mg/100 g), and iron (3.7 to 6.8 mg/100 g) content of the wild and domesticated cultivars. A wild progenitor of finger millet, Ecoracana subsp.africana was significantly higher in protein than four of the six domesticated accessions analyzed. The calcium and iron content of the wild progenitor was also significantly greater than that of two domesticated cultivars. The wild species was also found to be higher in lysine and five other essential amino acids. These results indicate that the nutritional value of finger millet may be significantly improved by selective crossbreeding of the cereal's wild and domesticated cultivars.     

Proximate composition and mineral content of selected Tanzanian vegetables and the effect of traditional processing on the retention of ascorbic acid,riboflavin and thiamine

Proximate composition, mineral content and the effect of traditional processing practices on the retention of ascorbic acid, riboflavin and thiamine were studied using amaranth, cowpea, peanut, pumpkin and sweetpotato leaves. Results of this study indicated that, crude protein, crude fat, carbohydrate and ash contents were in the range of 20.64–46.56 percent, 2.57–4.34 percent, 35.43–63.50 percent and 8.92–15.69 percent respectively. The mineral content per 100 g of fresh vegetables was in the range of 83.64–229.34 mg, 145.97–780.19 mg, 11.56–21.31 mg, 43.02–110.30 mg, 0.96–5.90 mg and 0.40–2.24 mg for Ca, K, Na, Mg, Fe and Zn respectively. For ascorbic acid, riboflavin and thiamine, concentrations in 100 g of fresh vegetables were in the range of 43.78–89.00 mg, 0.62–1.71 mg and 0.09–0.30 mg respectively. The traditional processing practices of sun/shade drying and storing in ventilated containers resulted in a significant (P<0.05) decrease in ascorbic acid, riboflavin and thiamine for all vegetables. Conventional blanching and cooking for up to 15 minutes resulted in a significant (P<0.05) increase in riboflavin content in cowpea, peanut and pumpkin greens while in amaranth and sweetpotato leaves, thermal processing resulted in a significant (P<0.05) decrease in the vitamin. Based on the results of this study, the vegetables were good dietary sources of minerals, carbohydrate and protein.     

Effect of processing and storage on the ascorbic acid (vitamin C) content of some pineapple varieties grown in the Rivers State of Nigeria

Ascorbic acid contents of the juice of four different pineapples species grown in the Rivers State of Nigeria were determined before and after storage of whole pineapple and processing and storage of the juice for two months. Ascorbic acid of the fresh juice ranged from 22.5 mg to 33.5 mg/100 g sample. After storage at room temperature (30–32 °C) of whole pineapple for two weeks, ascorbic acid was reduced to between 59 and 65 percent of the fresh juice. Processing the juice by pasteurisation reduced the ascorbic acid to between 28 and 46 percent while storage in plastic bottles for two months further reduced the ascorbic acid content to between 10 and 21 percent.     

Chemical composition of two semi-aquatic plants for food use

The seasonal variation in the nutrient composition ofEnhydra fluctuans andMarsilea quadrifolia, two edible semi-aquatic plants, was studied in order to promote their consumption as green leafy vegetables. Both plants had a high crude protein content throughout all harvesting seasons.Enhydra fluctuans had a low ash content and was a good source of -carotene (3.7 to 4.2 mg/100 g on a fresh weight basis).Marsilea quadrifolia exhibited wide fluctuations between seasons and was not very promising in nutrient composition when compared to other commonly used green leafy vegetables.     

Evaluation of mineral elements and ascorbic acid contents in fruits of some wild plants

The fruits of some wild plants were examined for their contents of mineral elements and ascorbic acid.High levels of ascorbic acid were found in fruits ofSclerocarya birrea (403.3 mg/100 g) andAdansonia digitata (337 mg/100 g). In nine of the fruits examined, the mineral contents (Ca, P) were comparable with average values found in common fruits. The iron contents were however 2–5 times higher than the values for common fruits.     

Nutritive value and effect of blanching on the trypsin and chymotrypsin inhibitor activities of selected leafy vegetables

Proximate composition, energy, mineral and vitamin contentsand the effect of blanching methods and times on the trypsinand chymotrypsin inhibitor activities were studied usingcabbage, collard, turnip, peanut, and sweet potato leaves.Results of this study indicated that, crude protein, crudefat, carbohydrate and ash contents were in the range of 15.5–25.6%, 1.4–6.5%, 60.4–73.1% and 6.8–7.5%,respectively. Total dietary fiber was lowest in cabbage (28.2 g/100 g) and highest in the collard leaves (43.1%)while energy content per 100 g of vegetables was highestin sweet potato leaves (402 kcal) and lowest in cabbage(379 kcal). The mineral content per 100 g of vegetableswere in the range of 33.4–249.8 mg, 241.2–471.2 mg,12.1–75.1 mg, 14.9–98.9 mg, 0.5–3.5 mg and 0.9–3.1 mgfor Ca, K, Na, Mg, Fe and Zn, respectively. For ascorbicacid, riboflavin, thiamin and total carotenoids, concentrations in 100 g of vegetables were in the range of45.1–112.7 mg, 0.2–0.3 mg, 0.3–0.8 mg and 2.0–7.3 mg,respectively. The trypsin inhibitory activity per gram ofthe vegetables was highest in collard (60.1 TIU/g) andlowest in peanut leaves (41.0 TIU/g). Chymotrypsin inhibitoractivity was highest in the peanut (69.6 CIU/g) but lowestin the collard leaves (48.0 CIU/g). Both trypsin and chymotrypsin inhibitor activities were significantly (p<0.05) reduced by most of the treatments in eitherthe conventional or microwave blanching methods. In the conventional blanching method, trypsin inhibitor activitywas reduced by 0.5, 6.8, 11.9, 9.0 and 19.3 percent in cabbage, collard, turnip, sweet potato and peanut leaves,respectively, when the vegetables were blanched for 2.5 minutes but after blanching for 10 minutes, the trypsininhibitor activity was reduced by 29.7, 34.9, 54.3, 52.3and 65.6 percent in cabbage, collard, turnip, sweet potatoand peanut greens, respectively. For the microwave ovenblanching, trypsin inhibitor activity was reduced by 3.8,3.3, 32.7, 5.0 and 9.5 percent in cabbage, collard, turnip,sweet potato and peanut leaves, respectively when thevegetables were blanched for 30 seconds. When blanched for60 seconds, trypsin inhibitor activity was reduced by 16.2,45.8, 46.2, 51.0 and 42.4 percent in cabbage, collard, turnip, sweet potato and peanut greens, respectively.Similar trends in the reduction of chymotrypsin inhibitoractivity were observed when the vegetables were conventionally blanched for 2.5, 5 and 10 minutes andwhen blanched by microwave oven for 30, 45 and 60 seconds.Based on the results of this study, the vegetables weregood dietary sources of minerals, vitamins, carbohydrateand proteins. Also, blanching was an effective method forreducing the trypsin and chymotripsin inhibitor activitiesin the leafy vegetables, however, further investigation onthe heating times for both conventional and microwaveblanching methods is suggested.     

Fatty Acids and Carotenes in Some Ber (<Emphasis Type="Italic">Ziziphus jujuba Mill</Emphasis>) Varieties

Several jujube varieties from the southeast of Spain were analyzed for fatty acid and carotene contents. Triglycerides having medium-chain fatty acids were most abundant in all samples. The main fatty acids were 12:0 (18.3 ± 9.97), 10:0 (12.5 ± 19.0), 18:2n6 (9.27 ± 7.26), 16:1n7 (8.50 ± 5.77), 16:0 (7.25 ± 4.35), and 18:1n9 (5.34 ± 2.52) on total saponifiable oil. The fruits yield 1.33 ± 0.17 g/100 g saponifiable oil on a dry weight basis. Fatty acid profiles of fruits were found to be influenced by their developmental stage. Multivariable data analyses show that the samples could be grouped on the basis of their fatty acid content. Carotenes were found to be in good agreement with other fruits, varying from 4.12 to 5.98 mg/100 g on a dry weight basis. The contribution to vitamin value reach a mdium of 38 g RE/100 g on a fresh weight basis.     

Effect of Spinacia oleraceae L. and Perilla frutescens L. on Antioxidants and Lipid Peroxidation in an Intervention Study in Healthy Individuals

Daily consumption of fruits and vegetables is frequently recommended to prevent several diseases. This health-promoting effect is considered to be in part due to the antioxidant content of fruits and vegetables and their ability to decrease oxidative stress. To investigate whether the ingestion of preparations from spinach or perilla, two carotenoid-rich leafy vegetables, is followed by an increase in carotenoid concentration and/or affects parameters of oxidative stress in human blood plasma. 12 healthy volunteers ingested a perilla- or spinach preparation for 10 days (5 mg lutein/d). We quantified antioxidant levels in plasma, kinetics of lipid peroxidation, MDA concentration, and total antioxidative capacity of plasma. We observed a significant increase in lutein content and a moderate increase (n.s.) in β-carotene content in human blood plasma after consumption of spinach or perilla. The markers of lipid peroxidation tended to decrease, but no influence on antioxidative capacity of plasma could be detected. The high lutein content of perilla caused a more pronounced increase of lutein compared to spinach. Both vegetables seem to be able to influence lipid peroxidation in a beneficial manner.