This study compared the effect of a snack with ingredients to slow carbohydrate digestion (Test-snack) on postprandial blood glucose and insulin concentrations and subjective appetite ratings. We hypothesized that Test-snack would lower glucose and insulin responses and reduce appetite compared with a Control-snack. Overweight or obese subjects (n = 17) completed a randomized crossover study. Glucose, insulin, and appetite ratings were measured before consuming each snack or white bread (Bread) and over a period of 4 h. Subjects received Test-snack, Control-snack, or Bread in random order at least a week apart. The a priori primary outcome was the glucose response, and the secondary outcomes were appetite ratings and insulin responses. Mixed effects statistical models were used to perform analysis of variance in terms of the area under curve (AUC) and at specific time points. The 2-h AUC for glucose was significantly lower with Test-snack compared to Control-snack and Bread (AUC and 95% confidence intervals: Test = 2186.43 [1783.36-2589.51]; Control = 3293.75 [2893.97-3693.54]; Bread = 2800.28 [2405.79-3194.77] mg/dL · min). Four-hour AUC for glucose, and insulin, followed a similar pattern except that Test-snack did not differ from Bread. The glucose concentrations peaked at 45 min under all three conditions, but Test-snack elicited a lower response than Control-snack and Bread (P < .01). Test increased fullness and satisfaction and reduced hunger and prospective intake compared to Bread (P < .02), but was not significantly different from Control-snack. Ingredients that slow carbohydrate digestion in a snack reduce the postprandial glucose and insulin responses compared to a product without these ingredients.

Background: Slowly digested carbohydrates are perceived as beneficial by some consumers, and various regulatory bodies have published specific criteria defining lower postprandial glycemic response. We developed an optimized savory cluster snack containing slowly digested starch. Objective: We compared the glucose and insulin responses elicited by the optimized (test-) cluster, a control-cluster, and an available-carbohydrate-matched portion of white bread in healthy individuals. The primary outcome was blood-glucose peak rise. Methods: We tested healthy individuals (n = 25) on 3 occasions using a randomized crossover design. On each occasion, the participants provided fasting blood samples and then consumed 1 serving of test-cluster, control-cluster, or white bread. We then measured the participants' blood-glucose and serum-insulin concentrations over the next 4 h. Results: The test-cluster elicited a significantly lower blood-glucose peak rise (mean +/- SEM: 1.24 +/- 0.09 mmol/L) and incremental area under the curve (iAUC; 67 +/- 8 mmol x min/L) than the control-cluster (2.27 +/- 0.13 mmol/L and 117 +/- 10 mmol x min/L, respectively) and white bread (2.27 +/- 0.16 mmol/L and 114 +/- 9 mmol x min/L, respectively). The serum-insulin peak rise and iAUC elicited by the test-cluster (128 +/- 13 pmol/L and 6.10 +/- 0.73 nmol x min/L, respectively) and white bread (141 +/- 20 pmol/L and 6.47 +/- 1.11 nmol x min/L, respectively) were significantly lower than those elicited by the control-cluster (205 +/- 26 pmol/L and 9.60 +/- 1.31 nmol x min/L, respectively). Conclusions: The test-cluster elicited lower glucose and insulin responses than the control-cluster. The results support the hypothesis that the carbohydrates in the test-cluster are digested and absorbed slowly in vivo.

BackgroundConsumers are increasingly interested in snacks that supply energy over an extended period of time, potentially in the form of carbohydrates. Foods containing slowly released carbohydrates generally elicit attenuated postprandial blood glucose and insulin responses. A variety of ingredients and processing and formulation techniques were screened and applied to develop an optimized active cracker containing carbohydrates that were slowly digested in‐vitro, including a whole‐grain composite ingredient comprised of a hydrocolloid co‐processed with high‐amylose maize flour. The present study was undertaken to test the hypothesis that the active cracker, with a significantly lower ratio of rapidly available glucose to slowly available glucose in‐vitro, would elicit lower blood glucose and insulin responses than a control cracker in human subjects.MethodsHealthy men and women (n=25) were studied on 2 separate days using a randomized, double‐blind, cross‐over design. After 2 fasting finger‐prick blood samples were taken, subjects consumed 1 serving (56g) of the Active or Control Cracker and further blood samples were obtained over 4hr for serum glucose and insulin analysis. The 56g serving of Active (Control) Cracker, respectively, contained: protein, 3.9 (5.3)g; fat, 6.6 (6.5)g; carbohydrate, 42.4 (40.7)g; and fiber, 11.6 (1.7)g.ResultsCompared to the Control cracker, the Active cracker elicited a 36±3% lower glucose peak rise (1.59±0.09 vs 2.64±0.21 mmol/L, p<0.00001) and a 35±7% lower insulin peak rise (17.4±2.3 vs 31.9±4.6 uU/mL, p=0.00005). The glucose and insulin AUCs from 0–2 hr after the Active cracker were 36±4% (85±7 vs 146±15 mmol×h/L, p<0.05) and 39±10% 0.87±0.14 vs 1.79±0.33 mU×min/mL, p<0.05), respectively, lower than those after the Control cracker. The glucose AUC from 2–4hr after the Active cracker was significantly higher than Control (22.1±5.1 vs 12.9±3.6 mmol×h/L, p<0.05), whereas insulin AUC over 2–4hr was significantly less after the Active cracker compared to Control (0.15±0.05 vs 0.30±0.01 mU×min/mL, p<0.05).ConclusionsThe results support the hypothesis that the carbohydrates in the Active cracker are digested and absorbed more slowly in‐vivo than those in the Control, as predicted by the in‐vitro glucose release profile.Support or Funding InformationFunded by PepsiCo and Ingredion, Inc.

Postprandial glycemia has been implicated in the development of chronic metabolic diseases such as obesity, type 2 diabetes mellitus and cardiovascular diseases. Foods with high contents of slowly digestible starch elicit lower glycemic responses have been proposed as better choices to help decrease postprandial glucose excursions and thus to improve glycemic control and health, For this reason, there is a growing interest in developing foods with slowly digestible starch, particularly for snacks. A low moisture, low temperature process was developed to produce a savory cluster snack (test‐cluster) containing nuts and grains and bound together with wheat starch and soluble fiber which is slowly digested in‐vitro. The objective of this study was to compare the glucose and insulin responses elicited by the test‐cluster to those of a control‐cluster made with ingredients commonly used in commercially available snacks or bars including oats, peanuts, puffed rice and corn syrup and an available‐carbohydrate matched portion of white‐bread in healthy subjects. Healthy men and women (n=25) were studied on 3 occasions using a randomized, cross‐over design. After 2 fasting finger‐prick blood samples, subjects consumed 1 serving (56g) of the test‐ or control‐cluster or 47g white‐bread and had blood glucose and serum insulin measured at intervals over the next 4 hr. Each serving of test‐cluster, control‐cluster and white‐bread, respectively, contained: 5, 5 and 4g protein; 12, 11 and 0.5g fat; 24, 33 and 24g available‐carbohydrate; and 10, 2 and 1g dietary fiber. The blood‐glucose peak‐rise and incremental area under the curve (AUC) after test‐cluster were significantly lower than those after both control‐cluster and white‐bread (mean±SEM; peak‐rise, 1.24±0.09 vs 2.27±0.13 and 2.27±0.16 mmol/L; AUC, 67±8 vs 117±10 and 114±9, respectively). The serum‐insulin peak‐rise and AUC after test‐cluster, 128±13 pmol/L and 6.10±0.73 nmol×min/L, were similar to those after white bread, 141±20 pmol/L and 6.47±1.11 nmol×min/L, but significantly less than those after the control‐cluster, 205±26 pmol/L and 9.60±1.31 nmol×min/L. It is concluded that a serving of test‐cluster elicits lower glucose and insulin responses than a serving of a similar control‐cluster. The results support the hypothesis that the carbohydrates in the test‐cluster are slowly digested and absorbed in‐vivo.Support or Funding InformationThis study is funded by PepsiCo, Inc.

Introduction:The His-Purkinje system activates ventricular myocardium through Purkinje-Myocardial Junctions (PMJs).It has been suggested that most PMJs are normally non-functional at baseline due to source-sink mismatches at these junctions.We hypothesised that gap junctional uncoupling at the PMJs during acute ischaemia facilitates propagation across a greater number of functional PMJs, thereby leading to accelerated but more complex activation patterns.Methods: In aortic-perfused rabbit hearts (n ¼ 8), the right ventricles (RV) were exposed, preserving the Purkinje system (Figure ), and the endocardium optically mapped.Activation of the RV endocardium during atrial pacing was recorded during 40 minutes of global ischemia followed by 30 minutes reperfusion.A corresponding detailed 3D computer model of rabbit ventricles incorporating the Purkinje system was constructed to test the hypothesis.Results: Optical mapping studies revealed that the percentage of RV area activated within the first 5ms decreased from baseline 53 + 6% to 43 + 8% during early ischemia (,20 min), and paradoxically then increased to 59 + 8%, with more complex activation (p , 0.001).This coincided with more surface breakthroughs at more PMJs during late ischaemia (Figure).Activation normalised after reperfusion.In the computer model, a 6% reduction in conductivity was sufficient to render quiescent PMJs active.Increasing the fraction of functioning PMJs from 5% to 100% accelerated endocardial activation from 27.1 to 15.8 ms, compensating for reduced conduction velocity.Surface breakthroughs increased, as did the complexity of activation, matching the experiments.Conclusion: At baseline, most PMJs are quiescent.Ischaemia-induced closure of gap junction channels reduces conduction velocity, but as the uncoupling progresses, more PMJs become functional due to reduced source-load mismatch.The altered, more complex, activation patterns during ischaemia may be pro-arrhythmic as they increase the pathways for meandering wavefronts and the likelihood of wave collision.

A three-year study was conducted to investigate the accumulation of yeast assimilable nitrogen (YAN) during the final weeks of ripening in seven winegrape cultivars grown in New York State and to assess the feasibility of predicting harvest YAN using linear regression models. Berry samples of Vitis vinifera cvs. Cabernet franc, Chardonnay, Merlot, Pinot noir, and Riesling and interspecific hybrid cvs. Noiret and Traminette were collected weekly from 49 vineyard sites across the Finger Lakes, Hudson Valley, Lake Erie, and Long Island growing regions from August through harvest. YAN concentrations in Cabernet franc, Riesling, and Traminette were generally low, averaging <100 mg/L annually, while Chardonnay and Pinot noir had average YAN concentrations >200 mg/L. During the ripening period, linear regression models predicted harvest YAN up to five weeks before harvest (R-2 = 81.6%). A decrease in YAN during ripening was observed across cultivars, caused primarily by decreases in ammonia (AMM), as primary amino nitrogen levels remained stable. Population distributions were used to estimate appropriate prophylactic nitrogen additions for each cultivar, minimizing the risk of deficiency or excess; this was most difficult with Chardonnay, Noiret, and Pinot noir, which had the highest and most variable YAN concentrations and subsequently run the greatest risk of oversupplementation with prophylactic additions.

Many fermentation volatiles important to wine aroma potentially arise from yeast metabolism of hexose sugars, but assessing the relative importance of these pathways is challenging due to high endogenous hexose substrate concentrations. To overcome this problem, gas chromatography combustion isotope ratio mass spectrometry (GC-C-IRMS) was used to measure high-precision (13)C/(12)C isotope ratios of volatiles in wines produced from juices spiked with tracer levels (0.01-1 APE) of uniformly labeled [U-(13)C]-glucose. The contribution of hexose to individual volatiles was determined from the degree of (13)C enrichment. As expected, straight-chain fatty acids and their corresponding ethyl esters were derived almost exclusively from hexoses. Most fusel alcohols and their acetate esters were also majority hexose-derived, indicating the importance of anabolic pathways for their formation. Only two compounds were not derived primarily from hexoses (hexanol and isobutyric acid). This approach can be extended to other food systems or substrates for studying precursor-product relationships.

ADVERTISEMENT RETURN TO ISSUEPREVAddition/CorrectionORIGINAL ARTICLEThis notice is a correctionCorrection to Quantifying the Contribution of Grape Hexoses to Wine Volatiles by High-Precision [U13C]-Glucose Tracer StudiesMark A. Nisbet, Herbert J. Tobias, J. Thomas Brenna, Gavin L. Sacks*, and Anna Katharine MansfieldCite this: J. Agric. Food Chem. 2014, 62, 35, 8919Publication Date (Web):August 25, 2014Publication History Published online25 August 2014Published inissue 3 September 2014https://pubs.acs.org/doi/10.1021/jf503995vhttps://doi.org/10.1021/jf503995vcorrectionACS PublicationsCopyright © 2014 American Chemical Society. This publication is available under these Terms of Use. Request reuse permissions This publication is free to access through this site. Learn MoreArticle Views282Altmetric-Citations-LEARN ABOUT THESE METRICSArticle Views are the COUNTER-compliant sum of full text article downloads since November 2008 (both PDF and HTML) across all institutions and individuals. These metrics are regularly updated to reflect usage leading up to the last few days.Citations are the number of other articles citing this article, calculated by Crossref and updated daily. Find more information about Crossref citation counts.The Altmetric Attention Score is a quantitative measure of the attention that a research article has received online. Clicking on the donut icon will load a page at altmetric.com with additional details about the score and the social media presence for the given article. Find more information on the Altmetric Attention Score and how the score is calculated. Share Add toView InAdd Full Text with ReferenceAdd Description ExportRISCitationCitation and abstractCitation and referencesMore Options Share onFacebookTwitterWechatLinked InRedditEmail PDF (110 KB) Get e-Alertsclose Get e-Alerts

A three-year study was conducted to determine if regression models could be developed to predict yeast assimilable nitrogen (YAN) before harvest, using Riesling in the New York Finger Lakes region as a model. Berry samples were taken from 62 commercial Riesling vineyards around the Finger Lakes at veraison, two weeks before harvest, and harvest. Samples were measured for berry weight, Brix, pH, titratable acidity, ammonia, primary amino nitrogen, and yeast assimilable nitrogen (YAN). The average YAN concentration at harvest was 91.8 mg/L, and there were no significant differences in harvest YAN concentration among years. Linear regression models created using preharvest YAN concentrations (p < 0.05) had a cross-validated R-2 (Q(2)) of 70%. Models using only preharvest ammonia had less predictive power (Q(2) = 63%) but may allow winemakers more analytical flexibility than those requiring complete YAN measurements. Models created using multiple linear regression provided better predictive power (Q(2) = 73.6%). Finally, a multivariate approach using partial least squares regression was used to create models with the highest predictive power (Q(2) = 74.2%). The additional analysis required to obtain values for additional prediction variables may limit the practicality of multiple linear regression and partial least squares approaches. Because many winemakers are not able to perform the analyses required to calculate YAN during the busy time of harvest, the development of these regression models as predictive tools may allow winemakers to use preharvest analysis to calculate accurate supplemental nitrogen additions, allowing targeted supplementation and lowering the risk of excessive prophylactic additions.

# Quantitative Analysis of Phytic Acid in Grape Seeds, Stems, and Berries of Cabernet franc and Petit Verdot {#article-title-2} Phytic acid is a strong chelator and antioxidant naturally present in plant seeds. It has been shown to help prevent metal cation catalyzed oxidation and improve protein

s are in the approximate order as noted in the conference program. Abstracts here are those submitted and accepted through the 2012 ASEV-ES Annual Meeting Call for Abstracts. * Indicates corresponding author; † indicates presenting author. doi: 10.5344/ajev.2012.ea Quantitative Analysis of Phytic Acid in Grape Seeds, Stems, and Berries of Cabernet franc and Petit Verdot Zhiyu He† and Brent Trela.* Department of Plant and Soil Science, Texas Tech University, Lubbock, TX 79409 (trelab@alertaesthetics. com) Phytic acid is a strong chelator and antioxidant naturally present in plant seeds. It has been shown to help prevent metal cation catalyzed oxidation and improve protein stability in wine, although it is not a permitted additive in wine. This research was undertaken to quantify phytic acid content in grape stems and berry parts, those parts involved in the winemaking process that might contribute phytic acid to the resulting wine, and thus provide evidence that phytic acid may be an appropriate wine additive. Phytic acid was measured in grape berries and stems of Cabernet franc and Petit Verdot. There were significant differences in concentration between the two varieties and among stem and berry parts. Cabernet franc and Petit Verdot phytic acid contents ranged from ~14.6 to 23.4 mg in 1 gram of fresh berry at veraison to 9.8 to 6.9 mg/g at harvest (23.6 to 24.1 Brix), respectively. More than 80% of the phytic acid content in the grape berries for both varieties was found in the seeds, 3 to 9% was found in the skins, and the remainder in the pulp. Phytic acid content on a fresh weight basis in Cabernet franc stems decreased from 36.1 mg/g at veraison, to 28.7 mg/g at the middle of maturation, and then increased to 50.5 mg/g at harvest. Results on a dry weight basis also showed similar changes in phytic acid content. Although not measured, these changes may be due to transportation and utilization of phytic acid as a phosphorous source. Understanding the Relationship between FermentationDerived Aromas and Juice Nitrogen Composition Mark Nisbet,† Anna Katharine Mansfield,* Tim Martinson, and Gavin Sacks. Department of Food Science, New York State Agriculture Experiment Station, Cornell University, Geneva, NY 14456 (akm87@ cornell.edu) Fusel alcohols and their acetate esters are important components of a wine’s sensory profile. Their final concentration is a function of the nitrogenous compounds found in grape must, such as ammonia (AMM) and primary amino acids (PAN), known collectively as yeast assimilable nitrogen (YAN). The YAN content of New York grapes varies widely, often not meeting the concentrations required for efficient fermentation. Low nitrogen is associated with the production of sulfur off-odors, so supplementation is common. Inorganic nitrogen, added as diammonium phosphate, is the simplest and least expensive. Complex nitrogen sources are costly and consist of hydrolyzed yeast extracts containing PAN. Fusel alcohols can arise from two different pathways: catabolism of amino acids via the Ehrlich pathway and metabolism of sugar through anabolic pathways. The relative contribution of each pathway is currently unknown. This project aims to elucidate the contribution of volatiles from catabolic and anabolic pathways under variable nitrogen concentrations using gas chromatography–isotope ratio mass spectroscopy. The results will be modeled using partial least squared regression techniques to predict the concentration of fusel alcohols and esters based on PAN concentration. The model will be validated in Riesling musts gathered from sites around New York State. This method is new to wine applications and has the potential to allow enhancement of aroma compounds through targeted nutrition. A clearer understanding of this system will allow winemakers to finetune the amount and types of nitrogen supplements used, reducing costs and enhancing wine quality. Effect of Cold Soak and On-Skin Fermentation on the Phenolic Content of Aromatic White Wines Diane M. Schmitt,† David C. Manns, and Anna Katharine Mansfield.* New York State Agriculture Experiment Station, Cornell University, Geneva, NY 14456 (akm87@cornell.edu) In aromatic white wines produced from Vitis vinifera and hybrid grape cultivars, phenolic compounds may contribute to color and taste. In an effort to determine the impact on phenolic concentration in aromatic white wines, replicates of Riesling, Gewüztraminer, and Valvin Muscat were cold-soaked for 2, 4, 24, and 48 hr, and fermented on the skin for 7 days. Samples were collected after rushing, pressing, and at the end of fermentation for quantitative analysis of phenolic compound composition using HPLC. HPLC analysis revealed that gallic acid, protocatechuic acid, catechin, epicatechin, grape reaction product, t-caftaric acid, c-coutaric acid, t-coutaric acid, t-fertaric acid, and quercetin-3-glucoside were the most prevalent phenolic compounds observed. In addition, coumaric acid, ferulic acid, caffeic acid, and quercetin-3-galactosidase where found in select samples of both Riesling and Gewürztraminer wines. Ethyl esters of caffeic and coumaric acid where also found in select Riesling samples, while dihydroxybenzoic acid, sinapic acid, coumaric acid, quercetin3-rhamnoside, and quercetin were found in select Gewürztraminer samples. Skin fermentation treatments showed the greatest increase in gallic acid, catechin, and epicatechin concentrations compared to the controls. Of the compounds analyzed, the flavan-3-ols and hydroxycinnamic acids, which contribute to bitterness and browning, are the most likely to affect wine sensory profiles. Composition of Enological Nutrients and Their Effect on Malolactic Fermentation Alison M. Sudano† and Ramón Mira de Orduña.* Department of Food Science and Technology, New York State Agricultural Experiment Station, Cornell University, Geneva, NY 14456 (rm369@cornell.edu) In current enology, it is customary to supply musts with nutrients to prevent sluggish and stuck fermentations. Enological nutrients may be legally added in most winemaking countries and may contain yeast and yeast-derived ingredients, ammonium salts, and vitamins. A recent market analysis reveals over 100 different commercial brands claiming varying compositions and enological advantages. However, in contrast to microbiological media used in laboratories, 580A – 2012 ASEV Eastern Section Abstracts Am. J. Enol. Vitic. 63:4 (2012) detailed compositional data about these nutrients are rarely available, which makes it difficult to evaluate their suitability to support wine microorganisms. In this study, six enological nutrients were subjected to a comprehensive analysis. Moisture, amino acid and vitamin profiles, elemental composition, and concentrations of inorganic ammonium, primary amino nitrogen, and glutathione were measured. Considerable differences were encountered among the nutrients. The elemental contents differed several-fold for some nutrients (Li, K, Ca, P, Mg, Zn, Fe, and Cu) and exceeded one order of magnitude for others (Na, S, and Mn). Significant differences were also found with regard to the vitamin and amino acid profiles and glutathione concentration. Because of their tedious nutritional requirements, wine lactic acid bacteria were chosen as test microorganisms to study the nutritional quality of the products. Two Oenococcus oeni and one Lactobacillus strain were grown in a hydroalcoholic test solution with added nutrients at two different titers (1 x 105 and 1 x 106 cfu/ mL). The extent of growth stimulation by individual nutrients was strain-dependent. The growth-supporting effect of nutrients was more pronounced at low inoculation densities. Hence, the ability of nutrients to stimulate growth seems more relevant for spontaneous MLF. At high inoculation rates, significant malic acid had already been depleted at the onset of growth. Amino Acid Profiles and Yeast Assimilable Nitrogen in Hybrid Winegrapes from the Eastern United States Amanda C. Stewart† and Christian E. Butzke.* Department of Food Science, Purdue University, 745 Agriculture Mall Drive, West Lafayette, IN 47907 (butzke@purdue.edu) Yeast assimilable nitrogen (YAN) is an important consideration in fermentation management. The two main sources of YAN are ammonium ions and α-amino acids. The impact of prefermentation amino acid profile and concentration on aroma and flavor development in wine is an area of current research and products have been designed to alter the amino acid profile to increase production of fruity esters by certain strains of Saccharomyces cerevisiae. This research operates largely under the assumption that proline and arginine are the most prevalent amino acids in winegrapes. Notwithstanding, we have observed substantially different amino acid profiles in winegrapes common to the Eastern United States. Comparison of profiles from hybrid varieties with Vitis labrusca parentage against profiles of Vitis labrusca varieties suggests that amino acid profile is heritable. We are also investigating this relationship for Vitis riparia hybrids and Vitis rotundifolia (Muscadine). Amino acid profile should be considered when designing yeast nutrients for hybrid and native winegrape applications. We have also surveyed YAN in winegrapes across several Midwest and Southern states, observing a range of 89 to 938 mg/L across one vintage, over 30 grape varieties, and four states. For some varieties, average YAN far exceeds our previous recommendations for YAN based on initial sugar content (200, 250, or 300 mg/L at 21, 23, or 25 Brix, respectively). Understanding the differences in amino acid profile and total YAN concentration between hybrids and Vitis vinifera is essential to developing targeted fermentation management strategies. Validation Study of Stir Bar Sorptive Extraction of Ultratrace Volatile Compounds in Wines Yanmei Zhang† and Brent Trela.* Department of Plant and Soil Science, Texas Tech Univers

# Cluster Thinning Affects Fruit Composition and Economic Sustainability of Riesling {#article-title-2} Cluster thinning (CT) is applied to reduce grapevine crop load and advance ripening parameters, but it also increases production costs and lowers yields. Riesling vines were subjected to four

AbstractIn order to determine which tobacco constituents give rise to reducing compounds in smoke as well as to find out what factors affected the reducing property of the latter, modifications of flue-cured tobacco by solvent extraction and chemical impregnations were carried out. While no unequivocal evidence has been obtained as to the main source of reducing activity, all the evidence suggests that lignin and phenolic compounds derived therefrom, are the main contributors to reducing activity. A number of cigarette parameters, strand width, expansion of tobacco, paper porosity and burn control additives were studied and found to have no significant effect, within the Iimits tested, on the reducing power of the smoke. On the other hand, additives such as glycerol, ethylene glycol, polyethylene glycol, polypropylene glycol and carbowax gave distinctly lower reducing activities. Examination of tobacco products showed Iower reducing activities in smoke from Cuban, Latakia and Turkish tobaccos, as well as in smoke from cigarettes made from Indian sun-cured and French dark, fermented tobaccos. The lowest reducing activity was recorded for the highly fermented Perique tobacco. Indian ''bidis'' have specific reducing activities similar to those of standard flue-cured cigarettes. Freshly harvested, rapidly dried green tobacco as well as dried beech leaves, gave specific reducing activities close to those obtained for regular cigarettes. On the other hand, commercially available lettuce cigarettes, which undergo a fermentation step in their manufacture, gave distinctly lower specific activity

AbstractCigarette smoke has been shown to contain free radicals in both the vapour and particulate phases. The present investigation was undertaken to find out whether these radicals could initiate or promote the formation of radical peroxides which might in turn lead to lipid peroxidation. To investigate this, a system involving the coupled oxidation of b-carotene and linoleic acid was utilized. In this coupled reaction, b-carotene is destroyed through oxidation by free peroxy radicals. The system can therefore be used as a convenient detector of auto-oxidative mechanisms in which peroxide radicals participate, as well as provide an assay for antioxidants, since in their presence oxidative destruction of b-carotene is blocked. Our results show that smoke did not contribute to the oxidative destruction of b-carotene but rather behaved as an antioxidant. Both smoke vapour and particulate matter were found to be highly antioxidant. A number of pure vapour phase components were tested and the bulk of antioxidant activity was found to be due to HCN. Smoke condensates from different tobacco types were compared and differentiated according to their relative efficiencies of antioxidant activities. For comparison, units of antioxidant activity were expressed as rate of change of optical density with time. The highest antioxidant activities were obtained with air-, flue-cured (cut) and perique tobaccos. Pipe tobacco had the least activity while cigar and flue-cured (granulated), stem and sheet tobaccos had intermediate values. Tests done on smoke fractions derived from the fractionation of total condensate revealed that antioxidant activity resided largely in the neutral and water-insoluble acid fractions with virtually no activity in the basic fractions. The mode of antioxidant action of tobacco smoke is discussed in terms of free-radical mechanisms.

AbstractBoth the vapour and particulate phases of tobacco smoke have been shown to retard benzoyI-peroxide-initiated polymerisation of vinyl acetate by interception of the radicals involved in the polymerisation process. The extent of inhibition of polymerisation by test compounds is estimated by measuring time taken for a mixture of monomer and benzoyl peroxide, immersed in a water-bath at 70°C, to reach a spontaneous boil and comparing it with the time required for a similar mixture with added retarder to reach boiling point. Units are expressed as minutes of inhibition per part per million of inhibitor × 10