Juice Supplementation Research Articles

Green vegetable drink consumption protects peripheral lymphocytes DNA damage in Korean smokers

Smoking increases indices of free radical-mediated damage of DNA which are potential underlying processes in the pathogenesis of many diseases. In this study, we evaluated whether 8 weeks of green vegetable drink (Angelica keiskei based juice) supplementation to smokers can be protective against lymphocytic DNA damage. Twenty smokers were given 240 ml of commercially available green vegetable drink every day for 8 weeks. The DNA damage was determined using single cell gel electrophoresis (COMET assay) and the damage was quantified by measuring tail length (TL), tail moment (TM), and percent DNA in tail. Eight weeks of green vegetable drink consumption resulted in a significant in lymphocytes DNA damage in all three measurements; TL, TM and % DNA in tail. These results support the hypothesis that green vegetable drink exerts a cancer-protective effect via a decrease in oxidative damage to DNA in humans.

Concord grape juice supplementation reduces blood pressure in Korean hypertensive men: Double‐blind, placebo controlled intervention trial

Many of the flavonoids found in grapes and grape products such as juice or wine have been known to exert antioxidant, anti-inflammatory, platelet inhibitory and arterial relaxing effects either in vitro, in animal studies and in human trials. This study was designed to test the effect of Concord grape juice consumption on altering blood pressure in hypertensive patients. Forty subjects were given 5.5 ml/kg body weight/day of either Concord grape juice (CGJ) or a calorie-matched placebo drink every day for 8 weeks. Blood pressure (BP) was measured on weeks 0, 4 and 8. Compared to baseline, in the CGJ group systolic BP was reduced on average by 7.2 mm Hg (p = 0.005) and diastolic BP was reduced on average by 6.2 mm Hg (p = 0.001) at the end of 8 weeks. Comparable changes in the group getting the placebo product were -3.5 mm Hg (NS) and -3.2 mm Hg (p = 0.05) Consuming Concord grape juice, which is high in polyphenolic compounds, may favorably affect BP in hypertensive individuals.

Orange Juice Ingestion and Supplemental Vitamin C Are Equally Effective at Reducing Plasma Lipid Peroxidation in Healthy Adult Women

Objective: To directly examine the contribution of vitamin C to the antioxidant potential of fruits and vegetables, the antioxidant effect of orange juice consumption (8 and 16 fl. oz.) was compared to the antioxidant effect of supplemental vitamin C (dosage equivalent to that supplied by 8 fl. oz. of orange juice).Methods: Subjects (n = 11; 28.6 ± 2.1 years) received each treatment in a 3 × 3 randomized crossover design, and each two-week treatment was preceded by a two-week washout. During the entire trial, subjects restricted fruit and vegetable consumption to ≤3 servings per day except the vitamin C-rich foods (items containing >20 mg/serving), which were restricted to ≤3 servings per week. A fasting blood sample was collected at the end of each washout and each treatment period.Results: Following washouts, plasma vitamin C and lipid peroxidation (plasma TBARS) were similar by treatment group and averaged 25.4 ± 3.6 μmol/L and 3.82 ± 0.10 nmol/mL respectively. Plasma vitamin C concentrations were similar following each treatment period, 37.9 ± 8.1, 45.8 ± 9.4, and 38.3 ± 12.4 μmol/L for the 8 and 16 fl. oz. orange juice treatments and the supplement treatment, respectively. All intervention treatments reduced plasma TBARS as compared to pretreatment values: −47% (p = 0.013), −40% (p = 0.083), and −46% (p = 0.015) for the 8 and 16 fl. oz. orange juice treatments and supplement treatment respectively.Conclusions:These data indicate that the regular consumption of 8 fl. oz. orange juice or supplemental vitamin C (∼70 mg/day) effectively reduced a marker of lipid peroxidation in plasma.

Antioxidant and hypolipidemic effects of a red grape juice supplement in hemodialysis patients

Antioxidant and hypolipidemic effects of a red grape juice supplement in hemodialysis patients

Daily grape juice consumption reduces oxidative DNA damage and plasma free radical levels in healthy Koreans

Grape contains flavonoids with antioxidant properties which are believed to be protective against various types of cancer. This antioxidative protection is possibly provided by the effective scavenging of reactive oxygen species (ROS), thus defending cellular DNA from oxidative damage and potential mutations. This study of healthy adults tested whether a daily regimen of grape juice supplementation could reduce cellular DNA damage in peripheral lymphocytes and reduce the amount of free radicals released. Sixty-seven healthy volunteers (16 women and 51 men) aged 19–57 years were given 480 ml of grape juice daily for 8 weeks in addition to their normal diet, and blood samples were drawn before and after the intervention. The DNA damage was determined by using the single cell gel (comet) assay with alkaline electrophoresis and was quantified by measuring tail length (TL). Levels of free radicals were determined by reading the lucigenin-perborate ROS generating source, using the Ultra-Weak Chemiluminescence Analyzer System. Grape juice consumption resulted in a significant decrease in lymphocyte DNA damage expressed by TL (before supplementation: 88.75±1.55 μm versus after supplementation: 70.25±1.31 μm; P=0.000 by paired t-test). Additionally, grape juice consumption for 8 weeks reduced the ROS/photon count by 15%, compared to the beginning of the study. The preventive effect of grape juice against DNA damage was simultaneously shown in both sexes. These results indicate that the consumption of grape juice may increase plasma antioxidant capacity, resulting in reduced DNA damage in peripheral lymphocytes achieved at least partially by a reduced release of ROS. Our findings support the hypothesis that polyphenolic compounds contained in grape juice exert cancer-protective effects on lymphocytes, limiting oxidative DNA damage possibly via a decrease in free radical levels.

EFFECTS OF INCREASING FLUID MILK INTAKE ON BONE MINERAL DENSITY IN RESPONSE TO RESISTANCE TRAINING IN ADOLESCENT FEMALES

Inadequate consumption of dairy products can compromise development of peak bone mass in adolescent women. PURPOSE The primary purpose of this study was to examine the effects of increasing fluid milk on bone health in girls engaged in a resistance training program. METHODS Thirty-two girls (13 to 17 yrs) who habitually consumed less than 3 servings of fluid milk per day were matched and then randomly assigned into either a milk (MG; n = 16) or juice (JG; n = 16) supplementation group. Subjects consumed 236 mL (24 oz) per day of either 1% fluid milk or juice in addition to the their habitual diet. Both groups completed a 12-wk heavy-resistance training program (3 days/wk). Whole body and regional bone mineral density (BMD) and content (BMC) were assessed at 0, 6, and 12 wks. Data were analyzed using a 2x3 ANOVA with supplement group (MG and JG) and time (weeks 0, 6, and 12) as main effects. RESULTS There were significant interaction (group × time) effects for whole body BMD (P £ 0.05) and lumbar spine BMD (P £ 0.05). The MG group demonstrated a nearly two-fold greater increase than the JG in whole body BMD (DMG = +0.013 vs. DJG = +0.007 g/cm2) and the magnitude of difference was greater for spine BMD (DMG = +0.029 vs. DJG = −0.015 g/cm2). CONCLUSION These findings indicate that providing 3 additional servings of milk per day in adolescent girls engaged in a resistance training program has favorable effects on whole body BMD, especially in the lumbar spine region. Supported by the National Dairy Council, Rosemont, IL.

Cranberry Juice to Reduce Bladder Biofilms and Infection in Geriatric and Spinal Cord Injured Patients with Dysfunctional Bladders

There is evidence to suggest that cranberry juice supplements improve the health of the urinary tract by inhibiting the binding of fimbriated uropathogenic E. coli to the bladder mucosa. In patients with neurogenic bladders, urinary tract infections (UTI) are particularly common and often poorly managed by antibiotic treatment. A double-blind, randomized, placebo-controlled trial was undertaken on 29 geriatric and spinal cord injured patients with dysfunctional bladders. They received three times daily at mealtimes a 4 oz bottle of cranberry juice (Ocean Spray Cranberries, USA) or a specially prepared synthetic placebo drink. Two episodes of UTI arose in week one of cranberry intake and none thereafter, compared to four episodes of UTI in 4 placebo patients in weeks four, six and 10. Mean bacterial adhesion counts on bladder cells of the patients rose during the first month of treatment in 71% of the placebo patients compared to only 31% of cranberry patients (p＜0.001). The difference persisted to some extent for the second and third months. Bacterial adhesion levels correlated with culture findings (higher adhesion and higher viable counts in urine) (p＜0.001), positive leukocyte nitrite tests (136±131 bacteria per cell versus 52±86 in negative tests) (p＜0.001), and higher white blood cell counts (＞10) per high power field (126±125 versus 48±85 bacteria per cell) (p＜0.001). E. coli was the most frequently isolated organism (40% samples) followed by K. pneumoniae (17%) and a number of other uropathogens. Group B Streptococci, and coagulase negative Staphylococcus were recovered from urine in 4 samples but were not associated with any red blood cell presence. The daily intake of cranberry juice, in amounts which are not detrimental to long term compliance, appeared to have a role in reducing the risk of bladder colonization and infection in a highly susceptible patient population.

Fruit juice consumption modulates antioxidative status, immune status and DNA damage

Polyphenolic compounds exert a variety of physiological effects in vitro including antioxidative, immunomodulatory and antigenotoxic effects. In a randomized crossover study in healthy men on a low-polyphenol diet, we determined the effects of 2 polyphenol-rich juices (330 ml/d) supplemented for 2 weeks on bioavailability of polyphenols, markers of antioxidative and immune status, and reduction of DNA damage. Juices provided 236 mg (A) and 226 mg (B) polyphenols with cyanidin glycosides (A) and epigallocatechin gallate (B) as major polyphenolic ingredients. There was no accumulation of plasma polyphenols after two weeks of juice supplementation. In contrast, plasma malondialdehyde decreased with time during juice interventions. Moreover, juice consumption also increased lymphocyte proliferative responsiveness, with no difference between the two juices. Interleukin-2 secretion by activated lymphocytes and the lytic activity of natural killer cells were significantly increased by both juices. Juice intervention had no effect on single DNA strand breaks, but significantly reduced oxidative DNA damage in lymphocytes. A time-delay was observed between the intake of fruit juice and the reduction of oxidative DNA damage and the increase in interleukin-2 secretion. We conclude that consumption of either juice enhanced antioxidant status, reduced oxidative DNA damage and stimulated immune cell functions. However, fruit juice consumption for 2 weeks did not result in elevated plasma polyphenols in subjects after overnight fasting. Further studies should focus on the time-delay between juice intake and changes in measured physiological functions, as well as on active polyphenolic metabolites mediating the observed effects.

EFFECTS OF INCREASING FLUID MILK INTAKE ON BODY COMPOSITION RESPONSES TO RESISTANCE TRAINING IN TEENAGE BOYS

Data from animal and human epidemiological and longitudinal studies provide a link between increased availability of calcium with increased lipolysis and decreased fat mass. The purpose of this study was to examine the effects of increasing fluid MILK intake on body composition after a 12-week resistence training program in teenage boys. Twentyeight teenage boys (aged 13–17 yrs) who habitually consumed less than 3 serving of fluid MILK per day were matched and then randomly assigned into either a MILK (n = 14) or JUICE (n = 14) supplementation group. Subjects consumed 240 mL (24 oz) per day of either 1% fluid MILK or JUICE in addition to the their habitual diet. Both groups completed a 12-week periodized heavy-resistance training program consisting of supervised one-hour exercise sessions three days per week utilizing all major muscle groups. Body composition was assessed at 0, 6, and 12 weeks using dual-energy X-ray absorptiometry. Body mass significantly increased in the MILK and JUICE groups from Week 0 to Week 6 (+1.2 and +1.1 kg, respectively) with no further significant changes from Week 6 to Week 12 (−0.1 and +0.7 kg, respectively). Percent body fat significantly decreased in the MILK and JUICE groups from Week 0 to Week 6 (−1.2 and û1.5%, respectively) and there was a further significant decrease in the MILK group from Week 6 to Week 12 (−1.0%) while the JUICE group demonstrated no significant change from Week 6 to Week 12 (+0.1%) Similar to percent body fat, fat mass decreased at Week 6 in both groups but only the MILK group continued to lose fat mass at Week 12. Lean body mass significantly increased to the same extent in the MILK and JUICE groups from Week 0 to Week 6 (+1.9 and +1.9 kg, respectively) with no further significant changes from Week 6 to Week 12 (+0.5 and +0.5 kg, respectively). These findings indicate that heavy resistance training has favorable effects on body composition in teenage males. In addition, increasing fluid milk intake in teenage boys engaged in a resistance training program may lead to further reductions in fat mass, possibly due to higher intake of dietary calcium. Supported by the National Dairy Council, Rosemont, IL.

Infantile scurvy: a historical perspective.

Scurvy, a disease of dietary deficiency of vitamin C, is uncommon today. Among diseases, scurvy has a rich history and an ancient past. The Renaissance (14th to 16th centuries) witnessed several epidemics of scurvy among sea voyagers. In 1747, James Lind, a British Naval surgeon, performed a carefully designed clinical trial and concluded that oranges and lemons had the most antiscorbutic effect. Eventually, with the provision of lemon juice to the sea voyagers, scurvy became rare at sea. Infantile scurvy appeared almost as a new disease toward the end of the 19th century. The increased incidence of infantile scurvy during that period was attributed to the usage of heated milk and proprietary foods. Thomas Barlow described the classic clinical and pathologic features of infantile scurvy in 1883. Between 1907 and 1912, Holst and Frolich induced and cured scurvy in guinea pigs by dietary modification. In 1914, Alfred Hess established that pasteurization reduced the antiscorbutic value of milk and recommended supplementation of fresh fruit and vegetable juices to prevent scurvy. Such pioneering efforts led to the eradication of infantile scurvy in the United States. A brief history of infantile scurvy is provided.

Pomegranate Juice Supplementation to Atherosclerotic Mice Reduces Macrophage Lipid Peroxidation, Cellular Cholesterol Accumulation and Development of Atherosclerosis

Inhibition of lipid peroxidation contributes to the attenuation of macrophage cholesterol accumulation, foam-cell formation and atherosclerosis. Evidence suggests that nutritional antioxidants such as pomegranate juice (PJ) can contribute to the reduction of oxidative stress and atherogenesis. The goals of the present study were to determine whether such beneficial effects of PJ exist when supplemented to apolipoprotein E-deficient (E(0)) mice with advanced atherosclerosis and to analyze the antiatherosclerotic activity of a tannin-fraction isolated from PJ. Mice (4-mo-old) were supplemented with PJ in their drinking water for 2 mo and compared with age-matched placebo-treated mice, as well as to young (4-mo-old) control mice, for their mouse peritoneal macrophage (MPM) oxidative state, cholesterol flux and mice atherosclerotic lesion size. PJ supplementation reduced each of the proatherogenic variables determined in the present study compared with age-matched placebo-treated mice. It significantly induced serum paraoxonase activity and reduced MPM lipid peroxide content compared with placebo-treated mice and control mice. PJ administration to E(0) mice significantly reduced the oxidized (Ox)-LDL MPM uptake by 31% and MPM cholesterol esterification and increased macrophage cholesterol efflux by 39% compared with age-matched, placebo-treated mice. PJ consumption reduced macrophage Ox-LDL uptake and cholesterol esterification to levels lower than those in 4-mo-old, unsupplemented controls. PJ supplementation to E(0) mice with advanced atherosclerosis reduced the lesion size by 17% compared with placebo-treated mice. In a separate study, supplementation of young (2-mo-old) E(0) mice for 2 mo with a tannin fraction isolated from PJ reduced their atherosclerotic lesion size, paralleled by reduced plasma lipid peroxidation and decreased Ox-LDL MPM uptake. PJ supplementation to mice with advanced atherosclerosis reduced their macrophage oxidative stress, their macrophage cholesterol flux and even attenuated the development of atherosclerosis. Moreover, a tannin-fraction isolated from PJ had a significant antiatherosclerotic activity.

Green vegetable juice increases polyunsaturated fatty acid of erythrocyte membrane phospholipid in hypercholesterolaemic patients

Treatment with green vegetable juice rich in dark-green leafy and cruciferous vegetables, such as cabbage, was tested in 31 hypercholesterolaemic patients for three weeks. Green vegetable juice supplementation significantly increased the content of polyunsaturated fatty acids (PUFA; P); 18:2n-6, 20:3n-6, 20:4n-6, 20:5n-3, 22:4n-6, 22:5n-3 and 22:6n-3 of erythrocyte membrane phospholipid and decreased saturated fatty acids (SFA; S): 14:0 and 18:0, and therefore increased the polyunsaturated fatty acids/saturated fatty acids (P/S) ratio markedly from 0.26 ± 0.01 to 0.49 ± 0.01 (p<0.001). Green vegetable juice supplementation increased both n-6 and n-3 PUFA, but the increase of n-3 PUFA was greater than that of n-6 PUFA. Therefore, the n-6/n-3 ratio decreased significantly from 4.29 ± 0.42 to 3.00 ± 0.16 (p<0.05). Plasma thiobarbituric acid reactive substance production decreased, following the green vegetable juice supplementation. These results suggest that green vegetable juice may protect the erythrocyte membrane from oxidative stress, and the decrease in n-6/n-3 and increase in P/S ratio in the erythrocyte membrane phospholipid may be accompanied by rheological and functional changes in erythrocytes in hypercholesterolaemic patients.

Pomegranate juice consumption reduces oxidative stress, atherogenic modifications to LDL, and platelet aggregation: studies in humans and in atherosclerotic apolipoprotein E–deficient mice

Dietary supplementation with nutrients rich in antioxidants is associated with inhibition of atherogenic modifications to LDL, macrophage foam cell formation, and atherosclerosis. Pomegranates are a source of polyphenols and other antioxidants. We analyzed, in healthy male volunteers and in atherosclerotic apolipoprotein E-deficient (E(0)) mice, the effect of pomegranate juice consumption on lipoprotein oxidation, aggregation, and retention; macrophage atherogenicity; platelet aggregation; and atherosclerosis. Potent antioxidative effects of pomegranate juice against lipid peroxidation in whole plasma and in isolated lipoproteins (HDL and LDL) were assessed in humans and in E(0) mice after pomegranate juice consumption for </=2 and 14 wk, respectively. In humans, pomegranate juice consumption decreased LDL susceptibility to aggregation and retention and increased the activity of serum paraoxonase (an HDL-associated esterase that can protect against lipid peroxidation) by 20%. In E(0) mice, oxidation of LDL by peritoneal macrophages was reduced by up to 90% after pomegranate juice consumption and this effect was associated with reduced cellular lipid peroxidation and superoxide release. The uptake of oxidized LDL and native LDL by mouse peritoneal macrophages obtained after pomegranate juice administration was reduced by 20%. Finally, pomegranate juice supplementation of E(0) mice reduced the size of their atherosclerotic lesions by 44% and also the number of foam cells compared with control E(0) mice supplemented with water. Pomegranate juice had potent antiatherogenic effects in healthy humans and in atherosclerotic mice that may be attributable to its antioxidative properties.

Carotenoids in human buccal mucosa cells after 4 wk of supplementation with tomato juice or lycopene supplements

Lycopene has been identified as a phytochemical with potentially protective health benefits. Our objective was to monitor lycopene changes in buccal mucosa cells (BMCs) in response to 3 vehicles for oral delivery of lycopene. Fifteen healthy subjects ingested lycopene-rich tomato juice, tomato oleoresin, lycopene beadlets (each containing 70-75 mg lycopene) and a placebo for 4 wk each in a randomized crossover design while consuming self-selected diets. A 6-wk washout period separated the treatment periods. BMCs were collected at baseline and after 4 wk of supplementation. Lycopene in BMCs increased significantly ( approximately 2-fold) after 4 wk of ingestion of oleoresin and of beadlets to 4.95 (P < 0.001) and 3.75 microg/g protein (P = 0.053), respectively, but was not significantly affected by tomato juice treatment. The placebo treatment produced a significant decrease in BMC lycopene concentrations (P = 0.018). We observed significant treatment differences between oleoresin and tomato juice, oleoresin and placebo, and beadlets and placebo. BMC concentrations of phytofluene and beta-carotene, which were present in small amounts in the lycopene-containing treatments, increased significantly with ingestion of these products. Strong correlations were found between plasma and BMC concentrations of lutein, beta-cryptoxanthin, alpha-carotene, and beta-carotene. In contrast, correlations between lycopene concentrations in plasma and in BMCs were weak and not significant for any treatment. The cellular content of lycopene and other tomato-related carotenoids with proposed beneficial health effects can be increased through prolonged supplementation.

Chronic ingestion of lycopene-rich tomato juice or lycopene supplements significantly increases plasma concentrations of lycopene and related tomato carotenoids in humans

The bioavailability of lycopene from tomato juice and 2 dietary supplements, each containing 70–75 mg lycopene, was studied in 15 healthy volunteers in a randomized, crossover design. Subjects ingested lycopene-rich tomato juice, tomato oleoresin, lycopene beadlets, and a placebo for 4 wk each while consuming self-selected diets. Treatment periods were separated by 6-wk washout periods. Plasma lycopene concentrations, assessed at baseline and weekly throughout the treatment periods, were significantly higher during tomato juice, oleoresin, and lycopene beadlet ingestion than during placebo ingestion. Mean (±SEM) increases in plasma lycopene at week 4 of tomato juice, oleoresin, and lycopene beadlet ingestion were not significantly different: 0.24 ± 0.07, 0.23 ± 0.05, and 0.24 ± 0.06 mmol/L, respectively. Plasma concentrations of phytofluene and phytoene, which were present in small amounts in tomato juice, oleoresin, and lycopene beadlets, increased significantly with ingestion of these 3 products. b-Carotene, z-carotene, and 2,6- cyclolycopene-1,5-diol (a metabolite of lycopene)—also present in tomato juice and supplements—were significantly increased with consumption of the tomato juice and lycopene beadlets, but not with oleoresin consumption. A marked increase in plasma concentrations of an unknown compound was observed; it was detected in trace amounts in tomato juice, oleoresin, and lycopene beadlets, and had a maximum absorbance at 448 nm and a molecular weight of 556. Concentrations of plasma lycopene and other carotenoids with potential for enhancing human health can be increased by ingestion of realistic amounts of tomato juice. Lycopene appears to be equally bioavailable from tomato juice and the supplements used in this study. Am J Clin Nutr 1998;68:1187–95.

A Low-Viscosity Soluble-Fiber Fruit Juice Supplement Fails to Lower Cholesterol in Hypercholesterolemic Men and Women

This study was designed to determine whether a soluble dietary fiber supplement containing gum arabic and pectin in apple juice would lower serum lipids in 110 hypercholesterolemic men and women. Subjects were stabilized on an American Heart Association Phase I Diet for 8 wk. Those with elevated low density lipoprotein cholesterol levels, despite dietary modification, continued to follow the diet and were randomly assigned to receive 720 mL/d of apple juice containing 0 (control), 5, 9 or 15 g of gum arabic and pectin (4:1 ratio) for 12 wk, followed by a 6-wk apple juice-only washout phase. Serum lipid profiles, body weight and 3-day diet records were collected at 3-wk intervals. No significant differences among groups were observed in serum lipid responses during treatment or washout. During the treatment phase, mean serum total cholesterol and triglyceride concentrations increased by 3.5 and 28.5%, respectively (all groups combined, P < 0.0001). The high density lipoprotein cholesterol level did not change significantly from baseline in any group. During washout, mean total cholesterol concentration rose by an additional 2.4% (P < 0.05) compared with the value at the end of the treatment period, suggesting that the apple juice used to deliver the fiber supplement may have contributed to the adverse changes observed in the serum lipid profile. These findings do not support the hypothesized hypocholesterolemic effect of the gum arabic/pectin (4:1) mixture studied, but do underline the importance of selecting appropriate vehicles for delivery of dietary fiber mixtures.

Nitrogen Supplementation of Grape Juice. I. Effect on Amino Acid Utilization During Fermentation

The effect of supplementation of grape juice with diammonium phosphate (DAP) and arginine on consumption of amino acids during grape juice fermentation was examined in two commercial yeast strains, UCD 522 (Montrachet) and Prise de Mousse. Both strains displayed similar patterns of amino acid uptake during fermentation and seemed to be affected similarly by nitrogen supplementation. Nitrogen supplementation increased fermentation rate of both strains, and had a significant effect on biomass production for Prise de Mousse but not for UCD 522. The correlation between juice nitrogen content and fermentation rate was stronger in UCD 522 as compared to Prise de Mousse. Supplementation with low levels of DAP (0.23 g/L, the legal allowable limit for nitrogen supplementation) had very little impact on amino acid utilization in this juice. Very high levels of DAP (2.0 g/L) greatly decreased both the consumption and degradation of arginine provided in the medium. The presence of the polyamines putrescine, spermine, and spermidine decreased utilization and degradation of arginine significantly, but less strongly. The combination of polyamines and DAP at high concentration did not completely prevent degradation of arginine.

Nitrogen Supplementation of Grape Juice. II. Effect on Amino Acid and Urea Release Following Fermentation

The effect of nitrogen supplementation on the release of nitrogen-containing compounds post-fermentation was investigated in two commercial yeast strains, UCD 522 (Montrachet) and Prise de Mousse. Added nitrogen influenced both the total amount of nitrogen compounds released in the finished wine and their relative amounts. While the total nitrogen present in the finished wine was not significantly different for the two strains, Prise de Mousse released or failed to consume added arginine, leaving higher concentrations of this amino acid in the wine than found in wine fermented by UCD 522. UCD 522 also produced wines with higher urea levels than Prise de Mousse, and in both strains, supplementation with arginine resulted in higher post-fermentation levels of urea. Supplementation with diammonium phosphate reduced urea production by UCD 522 in juices high in arginine, but had no impact on urea levels in juices with a lower arginine content. Diammonium phosphate did not affect urea release in Prise de Mousse under any of the conditions tested. The effect of limited aeration on release of urea and amino acids post-fermentation was also investigated. Aeration of the fermentations resulted in higher levels of most amino acids post-fermentation compared to unaerated controls. However, urea levels were lower in the aerated samples as compared to the control fermentations for UCD 522. Aeration had no significant impact on urea production in Prise de Mousse.

Biological Assay of Nitrogen Content of Grape Juice and Prediction of Sluggish Fermentations

A bioassay based upon final culture absorbance was developed and utilized to estimate nitrogen content of grape musts. Amino acid analyses of grape musts were run for comparison to the values obtained from the bioassay. In Chenin blanc and French Colombard musts, there was a good correlation between nitrogen content as measured by biomass yield with that determined from amino acid analysis. The nitrogen content of Grenache musts showed a positive correlation with cell yield in the bioassay, but was not as strongly correlated as in the other two varieties. The amino acids generally recognized as good yeast nitrogen sources were more highly correlated with biomass yield than were poorer nitrogen sources. Ammonium ion supplementation of nutrient-deficient Chenin blanc juices either stimulated fermentation rate or had no effect, depending upon the juice. Ammonium utilization was found to be dependent upon the pH and ethanol concentration of the medium. Fermentation of nitrogen deficient musts was found to be stimulated by a variety of growth factors in addition to nitrogen.

Problems with folacin status with use of orange juice substitutes in a geriatric institution

An increased range of orange drinks is now available with varying proportions of orange juice. These have begun to appear in institutions for the care of elderly people. With evidence of folacin deficiency in such elderly people, we evaluated the effect of either 100% orange juice or an orange drink (at least 5% juice) on folacin status in 19 institutionalized elderly people over a 13‐week period. Serum folacin increased from 8.5 ± 0.8 to 13.2 ± 0.8 nmol/l (P &lt; 0.001) in 13 weeks, with 100 ml orange juice daily, but did not change from baseline (8.9 ± 0.8 nmol/l) to 13 weeks (8.5%± 0.7 nmol/l) with orange drink. By 6 weeks the difference between orange juice (11.0 ± 1.0 nmol/l) and orange drink (8.6 ± 0.7 nmol/l) was significant. Thus, not only is the choice of orange drink important, but small regular orange juice supplements can produce a significant increase in biochemical folacin status.