Unexpected sources of vitamin C

Sausages are quite common in the Norwegian diet. Presently the vitamin C content in sausages is listed as zero in the Norwegian Food Composition Table as well as in several other countries’ food composition tables. In the present study, five different kinds of sausages were analysed for relevant nutrients including vitamin C. One composite sample consisting of 15–16 subsamples was analysed for each sausage type. Vitamin C was measured by high-performance liquid chromatography (HPLC) with electrochemical detection as the sum of l-ascorbic acid and dehydro-ascorbic acid. The vitamin C content in the analysed sausages varied from 11 to 40 mg/100 g. This is explained by addition of vitamin C as an antioxidant by the manufacturer mainly to preserve colour. When recalculating vitamin C intakes from the most recent Norwegian national dietary surveys in adults, children and youths using the updated vitamin C values, total vitamin C intake increased by 3–10%. Other processed meat products such as cold cuts may also contain vitamin C as an antioxidant, and a larger impact on vitamin C intake may be seen if also these products turn out to contain considerable amounts of vitamin C. When planning analytical projects for food composition databases, care should be taken to include vitamin C for products where this vitamin may have been added for antioxidant purposes.     

Assay for vitamin D2 and vitamin D3 in plasma of dairy cows: changes after massive dosing of vitamin D3.

A sensitive, precise assay for vitamin D in plasma is described. Three to five milliliters of plasma were extracted with methanol:methylene chloride (2:1). The lipid extract was chromatographed on Sephadex LH-20 and then on lipidex-5000 columns. After high pressure liquid chromatography with a reverse phase chromatographic system, vitamin D2 and vitamin D3 were quantitated by ultraviolet absorbance. We used this assay system for monitoring daily changes of vitamin D3 in plasma of two Jersey cows after four intramuscular doses (15 x 10(6) IU) of vitamin D3 administered at weekly intervals. Basal vitamin D in plasma was 3.2 +/- .99 ng/ml with a range of 1.7 to 4.9 ng/ml. Vitamin D3 in plasma remained relatively low (10 to 45 ng/ml) the week after the first vitamin D3 injection. Vitamin D3 was high (130 to 234 ng/ml) after the second, third, and fourth injections. Vitamin D3 decreased steadily to 88 ng/ml by 38 days after the fourth vitamin D3 injection. Phosphorus in plasma increased sharply to a plateau at 9.5 mg/100 ml during the week after the second vitamin D3 injection and returned to normal (4.5 mg/100 ml) at the end of the experiment. Calcium, however, gradually increased to 14.0 mg/100 ml 20 days after the fourth vitamin D3 injection. Both animals remained hypercalcemic (calcium 11.5 mg/100 ml) during the experiment.     

无花果中维生素C含量的测定

目的 采用分光光度法测定无花果和无花果干中维生素C的含量。方法 选取一定浓度维生素C标准液进行波长扫描, 确定维生素C的最大吸收波长, 将待测样品匀浆处理后在此波长下进行分光光度测定。结果 维生素C的最大吸收波长为520 nm, 校准曲线方程Y=0.0208X+0.001(r2=0.9998), 无花果和无花干果中维生素C含量分别为69.08 mg/100 g和64.06 mg/100 g, 加标回收实验中回收率均在90%以上。结论 无花果中含有较高的维生素C, 且无花果维生素C含量高于无花果干中维生素C含量。     

Seasonal vitamin D intake in Quebec preschoolers.

As a number of seasonal factors affect cutaneous synthesis of vitamin D, especially in young children, our objective was to verify if winter and summer vitamin D intakes in Quebec preschoolers reach the adequate intake of 5 microg/day. A three-month retrospective food frequency questionnaire and a 24-hour food recall were used with parents of 98 children (mean age 56 months) in summer and of 72 of these children (mean age 65 months) in winter. To ensure completeness of data, vitamin D content of foods not covered in the Canadian Nutrient File was taken from other sources. According to the food frequency questionnaire, total vitamin D intakes were 9.7 +/- 4.3 microg/day in summer and 11.6 +/- 4.8 microg/day in winter. Only 10% of children in summer and 7% in winter had an intake below 5 microg/day. The 24-hour food recall vitamin D intake estimate was lower (summer 7.0 +/- 3.8 microg/day, winter 7.2 +/- 4.2 microg/day). This difference could be partly due to a discrepancy in the estimation of multivitamin supplement intake. However, according to both estimates, vitamin D intakes appeared generally adequate in this sample of Quebec preschoolers.     

Polyphenol and vitamin C contents in European commercial blackcurrant juice products

Vitamin C and polyphenol contents (anthocyanins, proanthocyanidins, phenolic acids and flavonols) were analysed in commercial blackcurrant juice products purchased from various European countries (Finland, Poland, Germany, United Kingdom) using HPLC methods. The aim was to study variation between countries, as well as evaluate the intake of polyphenols from commercial juices. There was significant variation in the contents of polyphenols and vitamin C between countries. Expressed as the ready-to-drink beverages, German, Polish, Finnish and British products averaged anthocyanin contents of 38, 32, 12 and 7.5 mg/2.5 dl, proanthocyanidin contents of 27, 24, 10 and 1.2 mg/2.5 dl, flavonol contents of 16, 15, 5.2 & 1.9 mg/2.5 dl and phenolic acid contents of 12, 8.9, 3.7 and 1.5 mg/2.5 dl, respectively. The mean vitamin C content was highest in British (70 mg/2.5 dl) and lowest in Finnish products (15 mg/2.5 dl). The intake of polyphenols from German and Polish ready-to-drink beverages was clearly higher than that from Finnish, and especially, British beverages.     

A comparison of flavonoids,carotenoids and vitamin C in commercial organic and conventional marinara pasta sauce

BACKGROUND: Characterising the levels of key phytochemicals in foods commonly consumed in the Western diet is critical for database development, estimating intake and assessing the potential health benefits associated with the consumption of these products. This paper describes a market‐basket evaluation of the key flavonoids, carotenoids and vitamin C in commercial organic (five brands) and conventional (five brands) marinara pasta sauces. RESULTS: Levels of ascorbic acid ranged from undetected up to 6.87 mg per 100 g fresh weight. The levels of total vitamin C in six of the ten samples were significantly lower than the amount listed on the Nutrition Facts Panel (P < 0.001 or P < 0.01). The contents of total vitamin C, flavonoids and lycopene were not statistically different between organic and conventional samples. Conventional pasta sauces demonstrated a significantly higher level of all‐trans‐β‐carotene (P < 0.05). CONCLUSION: This suggests that any beneficial differences in levels of flavonoids, carotenoids and vitamin C gained through cultivation practices are not measurable at the consumer level in processed tomato products. Additionally, the results point to a large disparity between the actual vitamin C content of these products and the content listed on the Nutrition Facts Panel. Copyright © 2007 Society of Chemical Industry     

Technical note: forms and route of vitamin C supplementation for cows.

The purpose of this study was to compare the effect of multiple oral supplementation of two forms of vitamin C on plasma ascorbic acid concentrations in dairy cows. Vitamin C was administrated at the rate of 40 g/d during a 5-d period. The supplements were vitamin C in the form of a fine powder and vitamin C coated with ethyl cellulose. In addition, another group of cows provided with vitamin C in the form of fine powder through an abomasal fistula was enrolled in the study. The effect of vitamin C supplementation was assessed by the change in plasma ascorbic acid concentrations during a 5-d period of vitamin C supplementation. A tendency existed for cows that were dosed with vitamin C in the abomasum to have higher ascorbic acid than cows supplemented orally. In the abomasum-dosed cows, plasma ascorbic acid value varied between 3.6 and 4.4 micrograms/ml; the maximum ascorbic acid content was 4.4 micrograms/ml at 54 h. Cows dosed orally with vitamin C coated with ethyl cellulose had higher plasma ascorbic acid concentrations than did cows that received vitamin C in the form of fine powder. In the former group, the maximum ascorbic acid concentration occurred at 30 h after dosing (5 micrograms/ml).     

Vitamin C in frozen,fresh squeezed,unpasteurized, polyethylene-bottled orange juice: a storage study

A storage study of frozen, fresh squeezed, unpasteurized, polyethylene-bottled orange juice was conducted to determine vitamin C loss on a monthly basis over a period of 24 months. Vitamin C content declined from an initial value of 40.6 mg/100 ml to 32.8 mg/100 ml in the final analysis for a loss of 19.2% over the storage period. A regression analysis showed a decrease of about 0.34 mg/100 ml of the vitamin C per month at this condition. The estimated shelf-life of this juice to meet the label claim of vitamin C of 130% DV is about 22 months at −23°C.     

Survey of the daily intake of nitrate and nitrite in school children by the duplicate portion method

The daily intake of nitrate and nitrite in school children (n = 100) in Hiroshima Prefecture was estimated directly by the duplicate portion method. The daily intake of nitrate was 68.42 +/- 77.49 mg. The daily intake of nitrate/kg body weight was 2.06 +/- 2.24 mg, which is about 56% of the acceptable daily intake (ADI). The daily intake of nitrite was 0.953 +/- 0.869 mg. The daily intake of nitrite/kg body weight was 0.027 +/- 0.021 mg, which is about 45% of the ADI. The daily intake of nitrite/kg body weight was significantly different between the obese group and the non-obese group in boys (p < 0.05, Mann-Whitney U-test). The rates of children whose daily intakes of nitrate and nitrite were above the ADI were 16% and 7%, respectively.     

含葡萄籽提取物的维生素C的测定

目的对3种维生素C检测方法进行比较,探索检测含葡萄籽提取物的样品中维生素C含量的适宜方法。方法用滴定法、紫外风光光度法、高效液相色谱法分别检测维生素C含量。结果以汤臣倍健祛斑胶囊为例,因葡萄籽提取物本身的强抗氧化性和颜色深的特性,用滴定法和紫外风光光度法检测维生素C的准确度偏差分别为87.73%和54.79%,用高效液相色谱法检测结果准确度偏差为0.38%,符合检测法规GB/T27404-2008中要求(当含量在1%~10%时,准确度偏差小于10%)。结论当样品中含有葡萄籽提取物时,用高效液相色谱法检测维生素C的准确性高。     

Effects of genotype and environment on vitamin C content and its heterosis in towel gourd fruits

BACKGROUND: Vitamin C is an indispensable component in the diet of humans, who lack the ability to synthesise it. Towel gourd (Luffa cylindrica L.) is a vegetable that is widely consumed in Asia, but little is known about the vitamin C content in its fresh fruits. In this study the effects of genotype and environment on the vitamin C content and its heterosis in towel gourd fruits were investigated using eight inbred lines and nine F₁ hybrids planted in two different seasons (spring and summer). RESULTS: Among the 17 cultivars studied, vitamin C content ranged from 5.94 to 12.89 mg per 100 g, suggesting the possibility of selecting new towel gourd varieties with high vitamin C content. The effects of genotype, environment (planting season) and their interaction on vitamin C content were all significant (P?0.01), with genotype having the largest effect. Five out of six hybrids showed positive heterosis over the mean values of their parents. However, it was difficult to predict the vitamin C content in F₁ fruits from that in their parents. CONCLUSION: The results of this study suggest that the vitamin C content in towel gourd fruits can be affected by genotype and environment and might be increased by crossing. This could provide a theoretical basis for selecting varieties with high vitamin C content. Copyright © 2007 Society of Chemical Industry     

Phytochemicals,vitamin C and sugar content of Thai wild fruits

The objective of the present study was to generate information about the potential health-enhancing properties of selected Thai wild fruits. Nineteen varieties of wild fruits, collected from the natural forest in north-eastern Thailand, were analysed for phytochemicals, anti-oxidant activity, vitamin C and sugar content. The results showed that Diospyros decandra Lour. exhibited the highest content of total phenolic compounds (215 mg GAE/g) and total flavonoid content (187 mg RE/g). Terminalia chebula Retz. had higher anti-oxidant activities than other fruits, as measured by 1,1-diphenyl-2-picrylhydrazyl radical scavenging (99% inhibition) and ferric reducing/anti-oxidant power assays (63 mmol FeSO₄/g). The sum of sugars (sucrose, glucose, fructose and galactose) ranged from 33 to 430 mg/g fresh weight, being dominated by glucose (ranging from 7.5 to 244 mg/g) and fructose (ranging from 5.3 to 193 mg/g). The highest content of vitamin C was found in Phyllanthus emblica Linn. (2.2 mg/g). Thai wild fruits, which were investigated in this study, have been shown to be a novel rich source of phytochemicals.     

Variations in the vitamin C content of imported tomatoes

An analysis was made of the vitamin C content of late winter tomatoes. A range of 6·8 to 31·2 mg reduced ascorbic acid per 100 g of fruit was observed in the batches of fruit examined in mid-March 1969. The mean value was 12·6 mg ascorbic acid per 100 g of fruit. It is emphasised that this mean figure was considerably lower than the 20 mg per 100 g given in McCance & Widdowson's (1967) ‘Tables of the Composition of Foods’ which are widely used in dietary surveys.     

Activity of pectinmethylesterase,pectin content and vitamin C in acerola fruit at various stages of fruit development

In order to know which stage of fruit development is better for acerola industrialization, we studied the PME specific activity, pectin content and vitamin C at various stages of development. The acerola fruits were classified according to colour and weight in five stages: immature green (2.62–3.21 g), green (4.04–4.83 g), mature green/yellow (5.03–5.88 g), pale-red (6.16–6.77 g) and ripe mature (6.92–8.37 g). The results showed that the highest content of pectin and vitamin C occurred at the immature green stage, 4.51±0.1% yield, 2424 mg/100 g of pulp and decreased as fruit ripened, 2.99±0.03% yield, 957±0.0 mg/100 g of pulp, respectively. However, at the same stages, the values of PME specific activity were lowest, 0.61±0.01 and 0.55±0.0 units g⁻¹/g of pulp, respectively. The highest value of PME activity was 2.08±0.01 units g⁻¹/g of pulp in the green stage.     

Effect of cooking on total vitamin C contents and antioxidant activity of sweet chestnuts (Castanea sativa Mill.)

In this work the total vitamin C contents (ascorbic acid + dehydroascorbic acid) and antioxidant activity of raw and cooked chestnuts was evaluated. The vitamin C contents of raw chestnuts varied significantly between the different cultivars (cv) studied and it varied from 400 mg/kg dry weight (cv Lada) to 693 mg/kg dry weight (cv Martaínha). The different cultivars behave differently during the cooking process concerning the loss of vitamin C. A significant decrease in the vitamin C content of the chestnuts was observed, 25–54% for the boiling process and 2–77% for the roasting process. Boiled and roasted chestnuts can be good sources of vitamin C since it may represent 22.4%, 16.2%, 26.8% and 19.4%, respectively, of the recommended dietary intake for an adult man and woman. The cooking process significantly changed the antioxidant activity of the chestnuts. A difference was observed between the cultivars during the cooking processes, concerning the antioxidant activity. For the raw chestnuts the variation in vitamin C content of the chestnuts explains 99% of the antioxidant activity variation but for the roasted and boiled chestnuts this percentage significantly decreases to 51% and 88%, respectively. Although a high antioxidant activity is still present in the cooked chestnuts, the cause for this antioxidant activity is less dependent on the vitamin C content of the chestnuts, probably due to the conversion of ascorbic acid to dehydroascorbic acid. The increase in gallic acid during the cooking process, presumably transferred from the peels to the fruit, also contributes to the high antioxidant activity observed for the cooked chestnuts.     

Red palm oil supplementation: a feasible diet-based approach to improve the vitamin A status of pregnant women and their infants

This double-blinded, randomized, controlled study was designed to study the effect of dietary supplementation with red palm oil during pregnancy on maternal and neonatal vitamin A status. A total of 170 women were recruited at 16 to 24 weeks of gestation and randomly assigned to an experimental group that received red palm oil to supply approximately one recommended dietary amount (RDA) (2,400 micrograms) of beta-carotene or to a control group that received an equivalent volume of groundnut oil. The women received the oils for a period of 8 weeks, starting at 26 to 28 weeks of gestation and extending to 34 to 36 weeks of gestation. The mean postintervention (34 to 36 weeks) levels of serum retinol were 1.20 +/- 0.22 (SD) mumol/L (95% CI, 1.15-1.25) in women receiving red palm oil and 0.73 +/- 0.15 mumol/L (95% CI, 0.69-0.77) in their infants; these levels were significantly higher than those in women receiving groundnut oil (1.07 +/- 0.26 mumol/L; 95% CI, 1.01-1.13; p < .01) and their infants (0.62 +/- 0.17 mumol/L; 95% CI, 0.57-0.67; p < .001). A significantly lower proportion of women in the red palm oil group than in the control group had vitamin A deficiency (serum retinol levels < 0.7 mumol/L) after intervention (1.5% vs. 9.7%). The proportion of women having anemia was significantly lower (p < .01) in the red palm oil-supplemented group (80.6%) than in the control group (96.7%). The mean birthweight and gestational age of the infants did not differ significantly between the two groups. An increased risk of low birth-weight (p = .003) and preterm delivery (p = .000) was observed with decreasing serum retinol levels in the third trimester of pregnancy. These results show that red palm oil supplementation significantly improved maternal and neonatal vitamin A status and reduced the prevalence of maternal anemia. Maternal vitamin A status in the later part of pregnancy is significantly associated with fetal growth and maturation. Hence red palm oil, a rich source of bioavailable vitamin A, could be used as a diet-based approach for improving vitamin A status in pregnancy.     

高效液相色谱法测定水果和蔬菜中维生素C含量的不确定度评定

通过分析维生素C测定过程中不确定度的来源,建立数学模型,评定出各不确定度分量,计算出合成标准不确定度和扩展不确定度。结果表明,当样品中维生素C含量为33.7 mg/100 g时,扩展不确定度为1.4 mg/100 g （k=2）;标准储备溶液的配制和测量重复性是不确定度的主要来源。     

Influence of different dietary vitamin C levels on vitamin E and C content and oxidative stability in various tissues and stored m. longissimus dorsi of growing pigs

Both vitamin E and C have antioxidative properties and may act synergistically. To examine a possible interaction between vitamin E, C and oxidative stability in various tissues, 40 barrows (25–105 kg body weight) were allocated to four cereal-based diets (13.4 MJ digestible energy/kg, 168 g crude protein/kg, 140 mg dietary dl-α-tocopheryl acetate) which were supplemented with 0 (B), 150 (C100), 300 (C200) or 600 (C400) mg/kg crystalline ascorbic acid. The influence of storage time on these factors in m. longissimus dorsi samples (LD) was investigated. Samples of liver (LI), heart (HT), spleen (SP), backfat outer layer (BF) and LD were obtained. Dry matter, vitamin E, vitamin C and thiobarbituric acid reactive substances (TBARS) were analyzed in all investigated tissues and in addition color (L^∗, a^∗, b^∗ values) and drip loss measurements in LD at day 0, 1, 2, 3, 4 and 8 were collected. The treatments did not influence growth performance and slaughter data of the pigs. Neither the vitamin E nor the vitamin C content of investigated tissues showed differences due to feeding treatments. There was also a lack of response to the amount in TBARS. Parameters in LD samples were only affected by storage time and not by diets. The results show that dietary use of both vitamins simultaneously did not further improve qualitative characteristics of the investigated pork tissues.     

Consumption of vitamin A by breastfeeding children in rural Kenya

Vitamin A deficiency remains a significant health risk in developing countries, affecting infants and children in particular. To counter child malnutrition, mothers are encouraged to breastfeed to ensure that their children receive adequate macro- and micronutrients, including vitamin A. However, this assumes that the mother has sufficient vitamin A intake to provide enough vitamin A to her child. This study investigates maternal and infant intakes of locally available foods of high vitamin A content in a rural agricultural community in Kenya. The study aims to establish the community risk for vitamin A deficiency and to assess whether breast milk is adequate to maintain and build retinol reserves of the breastfed infant. The study assesses 62 mother-child pairs and employs several methods to support its objectives, including the Helen Keller International food-frequency survey, maternal and infant anthropometric measurements, and maternal breast-milk and blood samples to determine breast-milk and serum retinol levels. We found that mothers with marginal (< 0.700 micromol/l) serum retinol and breast-milk deficient (< 1.05 micromol/l) in retinol accounted for 45.2% and 77.4%, of our sample, respectively. A significant (p < 0.05) proportion (40.3%) of mothers had breast milk deficient in retinol and marginal levels of serum retinol. The risk of vitamin A deficiency in breastfed infants older than six months was high, because 89.5% of them did not consume foods high in vitamin A content three times weekly. The primary source of vitamin A for infants younger than six months was breast-milk deficient in retinol vitamin A. This study suggests that in this rural community, breastfed infants may not receive appropriate foods with high vitamin A content and that although exclusive breastfeeding is advocated, most breast milk is deficient in retinol, further heightening the risk of vitamin A deficiency.     

Effects of UV‐B on vitamin C,phenolics, flavonoids and their related enzyme activities in mung bean sprouts (Vigna radiata)

In this study, ultraviolet‐B radiation (UV‐B) was used to effect the accumulation of vitamin C, phenolics and flavonoids in mung bean sprouts. Results indicate that the content of vitamin C and flavonoids increased during the initial period, and after a brief decline, reached peak levels of 25.29 ± 1.02 mg/100 g FW and 726.67 ± 7.35 mg/100 g DW, respectively, at 2.5 h (1.845 kJ m^?2), while the peak levels of the phenolics were 10741.33 ± 68.04 mg/100 g DW. The thiobarbituric acid reactive substances (TBARS) content decreases with the increase in irradiation time. The activities of the related enzymes, including phenylalanine ammonia‐lyase (PAL), L‐galactono‐1, 4‐lactone dehydrogenase (GalLDH), peroxidase (POD), polyphenol oxidase (PPO) and chalcone isomerase (CHI) were determined, which showed strong correlations with the change in the content of vitamin C, phenolics and flavonoids. In conclusion, the accumulation of vitamin C, phenolics and flavonoids in mung bean sprouts can be promoted by a low‐dose UV‐B irradiation.