Excessive Heat During Curing Influences TSNA in Dark Fire-Cured Tobacco

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1 2014 CORESTA Congress October 13, 2014 Quebec, Canada Paper AP02 Excessive Heat During Curing Influences TSNA in Dark Fire-Cured Tobacco W. A. Bailey and W. D. Pitt University of Tennessee Highland Rim Research & Education Center Springfield TN

more than 100 F, 38 C Color Setting 100 to 115 F, 38 to 46 C

2 Fire-Curing General Fire-Curing stages and target temperatures: Yellowing initial yellowing with no heat, then low fires at no more than 100 F, 38 C Color Setting 100 to 115 F, 38 to 46 C Drying 120 to 130 F, 49 to 54 C Finishing 110 to 120 F, 43 to 49 C

3 Dark Fire-Curing Some marketing contracts for dark-fired tobacco state that maximum temperatures should not exceed 54 C, even during stem drying stage Difficult to regulate heat with wood fire Temperatures often exceed 54 C at least slightly Aggressive curing in first cures 2-fire curing management Use of green, unseasoned wood Stage and duration of excessive heat critical for quality/scorching/bluing Not uncommon for temperatures to exceed 54 C, sometimes substantially. In addition to risk of reduced quality, preliminary data suggested than excessive heat may also affect TSNA

4 nornicotine TSNA in Tobacco *conversion nicotine * nornicotine + nitrite or NO x nitrate *curing nitrite NO x *fire-curing Diagram developed by Anne Jack, adapted from ID-160, KY & TN Tobacco Production Guide. NNN wood combustion

5 Objective Determine the effect of excessive heat (>160 F, 71 C) during curing on TSNA in dark fire-cured tobacco Compare final TSNA at end of curing Compare TSNA at each stage of curing

6 Methods 4 curing research trials conducted in 2011, 2012, and 2013 at the Highland Rim Research & Education Center in Springfield TN. PD 7318LC used in each trial and grown under standard production practices. 2 Experiments: : Effect of excessive heat during drying on TSNA at end of curing : Effect of excessive heat during color setting and drying on TSNA at each stage of curing

7 Methods End-of-cure sampling experiments: Tobacco housed in 2 identical, adjacent barns (360 sticks/barn) Normal Barn : Fire as normal to not exceed 130 F (54 C) Hot Barn : Attempt to obtain > 160 F (71 C) during drying stage Other fires normal heat Tobacco sampled from each barn at end of curing 10 samples per barn (5 from east side, 5 from west side) 20 leaves per sample (4 th leaf from top of 20 plants)

Methods Sequential sampling experiments: 2012-2013 Tobacco housed in 2 identical, adjacent barns (360 sticks/barn) Normal barn : fire as normal to not exceed 130 F (54 C) Hot barn : Attempt to obtain

8 Methods Sequential sampling experiments: Tobacco housed in 2 identical, adjacent barns (360 sticks/barn) Normal barn : fire as normal to not exceed 130 F (54 C) Hot barn : Attempt to obtain > 160 F (71 C) during multiple stages of the cure (beginning early during color setting through drying) Tobacco sampled from each barn at each stage of curing 5 sample stages: Yellowing, color set, drying, finishing, end of cure (takedown) 4 samples (reps) collected at each stage (20 samples per barn) Each sample was 6 leaves, 4 th leaf from the top of 6 plants

9 Temperature (F) Excessive Heat During Fire-Curing End-of-Cure Sampling HRREC, Springfield TN Normal Barn Temp Hot Barn Temp *Excessive heat during drying fire, max. temp 190 F (88 C) Max. temp normal barn 131 F (55 C) Hours Barn Monitoring during Fire-Curing

10 Effect of Excessive Heat on Dark-Fired TSNA End-of-Cure Sampling Experiment HRREC, Springfield TN Treatment Hot Barn Max. Temp 190 F (88 C) Normal Barn Max. Temp 131 F (55 C) Sample Rep NNN (ppm) NNK (ppm) NAB (ppm) NAT (ppm) Tot TSNA (ppm) East - 1st tier East - 2nd tier East - 3rd tier East - 4th tier East - 5th tier West - 1st tier West - 2nd tier West - 3rd tier West - 4th tier West - 5th tier East - 1st tier East - 2nd tier East - 3rd tier East - 4th tier East - 5th tier West - 1st tier West - 2nd tier West - 3rd tier West - 4th tier West - 5th tier Average Tot TSNA 8.77 ppm **** 3.18 ppm

11 Temperature (F) Excessive Heat During Fire-Curing End-of-Cure Sampling Experiment 2012 HRREC, Springfield TN Normal Barn Hot Barn *Excessive heat during drying fires, max. temp 166 F (74 C) Max. temp normal barn 122 F (50 C) Hours Barn Monitoring during Fire-Curing

12 Effect of Excessive Heat on Dark-Fired TSNA End-of-Cure Sampling Experiment HRREC, Springfield TN Treatment Hot Barn Max. Temp 166 F (74 C) Normal Barn Max. Temp 122 F (50 C) Sample Rep NNN (ppm) NNK (ppm) NAB (ppm) NAT (ppm) Tot TSNA (ppm) East - 1st tier East - 2nd tier East - 3rd tier East - 4th tier East - 5th tier West - 1st tier West - 2nd tier West - 3rd tier West - 4th tier West - 5th tier East - 1st tier East - 2nd tier East - 3rd tier East - 4th tier East - 5th tier West - 1st tier West - 2nd tier West - 3rd tier West - 4th tier West - 5th tier Average Tot TSNA ppm **** 4.46 ppm

13 Temperature (F) Excessive Heat During Fire-Curing Sequential Sampling Experiment 2012 HRREC, Springfield TN Normal Barn Hot Barn *Excessive heat during late yellowing, color setting, and drying, max. temp 180 F (82 C) Max. temp normal barn 95 F (35 C) Hours Barn Monitoring during Fire-Curing

14 Total TSNA (ppm) Effect of Excessive Heat during Fire-Curing on TSNA Sequential Sampling Experiment - HRREC, Springfield TN Normal Barn Hot Barn ** ** ** 15.22*** **** Yellowing Color Setting Stem Drying Finishing Takedown

15 Temperature (F) Excessive Heat During Fire-Curing Sequential Sampling Experiment 2013 HRREC, Springfield TN Normal Barn Hot Barn *Excessive heat during color setting and drying, max. temp 170 F (77 C) Max. temp normal barn 119 F (48 C) Hours Barn Monitoring during Fire-Curing

16 Total TSNA (ppm) Effect of Excessive Heat during Fire-Curing on TSNA Sequential Sampling Experiment - HRREC, Springfield TN Normal Barn 5.27* Hot Barn ** 3.12 Yellowing Color Setting Stem Drying Finishing Takedown

17 Summary Excessive heat did not reduce quality enough to render tobacco unmarketable in any experiment Excessive heat resulted in major increases in TSNA in all 4 experiments. End-of-cure sampling experiments: TSNA in hot barn approximately 3 X higher in 2011 and 2 X higher in 2012 than normal barns. Sequential sampling experiments: TSNA in hot barn approximately 5 X to 11 X higher throughout cure in 2012 and 2 X to 4 X higher in 2013.

18 Summary In end-of-curing experiments, magnitude of TSNA differences between hot barn and normal barn appeared to reflect relative differences in temperatures during drying. In sequential sampling experiments, magnitude of TSNA differences appear to reflect duration of excessive heat 3 hot firings during late yellowing to drying in hot firings during color setting and drying in 2013

19 Questions? Appreciation to Altria Client Services/U.S. Smokeless Tobacco Co. for support of this research

Test was abandoned as the 4-inch submersible pump (rated for 5 gpm) was clogged right after the pump was turned on.

Test was abandoned as the 4-inch submersible pump (rated for 5 gpm) was clogged right after the pump was turned on. # Test Purpose Date Duration Result Comments 1 BW6 constantrate pumping test; 7/31 Target duration: 48 hours Target rate= 5 pgm 1) Estimate large scale equivalent T and S interval of BW6; 2) Start a series