Characterising the change rule of freshness and inorganic anions in reconstituted tobacco pulp with oscillation time

doi:10.21203/rs.3.rs-3629966/v1

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Characterising the change rule of freshness and inorganic anions in reconstituted tobacco pulp with oscillation time

https://doi.org/10.21203/rs.3.rs-3629966/v1

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In order to study the change rule of freshness and acid ions in reconstituted tobacco slurry, the content changes of 17 organic acids and 5 inorganic anions in reconstituted tobacco slurry with different residence times under confined condition were determined by on-line solid-phase extraction ion chromatography in this study. The results showed that the changes of acetic acid, nitrate ion and isovaleric acid in different reconstituted tobacco slurries with oscillation time were regular and consistent, and the trends of the changes of acetic acid, nitrate ion and isovaleric acid in different reconstituted tobacco slurries with oscillation time were correlated with each other in a highly significant way. Taking the evaluation of olfactory aroma and sensory quality qualities of reconstituted tobacco pulps with different residence times as a benchmark, it was found that the variation patterns of nitrate ions and isovaleric acid in reconstituted tobacco pulps with oscillation time were consistent with the variation patterns of olfactory and sensory qualities in the process of closed oscillation; compared with the fresh pulp, the olfactory aroma and sensory qualities of tobacco pulps had unpleasant odours appearing when the content of nitrate ions was reduced by about 50%. The selection of isovaleric acid and nitrate ion as the characteristic components of tobacco reconstituted pulp for monitoring can provide technology for optimising pulp retention time and production process.

Physical sciences/Chemistry

Physical sciences/Chemistry/Analytical chemistry

reconstituted tobacco pulp

freshness

acid ion

In order to make better use of discarded tobacco leaves and tobacco wastes, reconstituted tobacco leaf flakes are a good method, which are made from tobacco stalks and leaves with a variety of additives, such as exogenous fibres, mineral fillers, processing aids, and tobacco extracts^[1–3]. Pulping is the process of separating stem fibres and tobacco leaf fragments by a pulper under mechanical force, and is one of the key technologies in the production of reconstituted tobacco flakes by papermaking. The properties of pulp directly affect the subsequent production process and product quality^[4]. During the production process, the pulp operating temperature is generally maintained at about 50°C, and some microorganisms are carried into the pulp system along with inorganic salts, polysaccharides, and other substances^[5]. Reclaimed tobacco sheet (RTS) pulp prepared by papermaking method contains lignin and hemicellulose from raw materials, a large number of fine fibres from mechanical pulping, pectin, proteins, inorganic salts, and organic acids^[6–7]. Large amounts of fine fibres, pectin, proteins, inorganic salts, organic acids and other ions produced during the papermaking process. During RTS processing, tobacco slurry flows in closed pipes and the richness of the slurry harbours microorganisms under the right conditions leading to an increase in the number of microbial species^[8–9]. The anaerobic bacteria in the slurry undergo anaerobic digestion and denitrification in a closed environment and release volatile fatty acids with unpleasant odour^[10–13].The quality of RTS is directly related to the volatile fatty acids in the slurry. Therefore, examining the relationship between the changes of acid radical ions in reconstituted tobacco slurry and its residence time and the slurry flavour, identifying the characteristic components of the changes in the flavour of reconstituted tobacco slurry, and monitoring the changes in the characteristic components will be helpful to ensure the operational quality of the slurry and provide a means of evaluating the quality of the slurry in production.

In recent years, odour fingerprinting techniques have been used for food flavour detection ^[14–15]. The method can also be used to determine the extent of microbial infection, and approximately 1000 microbial volatile organic compounds (MVOCs) have been identified, including alcohols, aldehydes, hydrocarbons, acids, ethers, esters, ketones, terpenes, sulphur and nitrogen compounds^[16]. Anaerobic bacteria can produce soluble organic compounds and volatile fatty acids during anaerobic hydrolysis/acidification^[17–19]. These volatile fatty acids provide a carbon source for these bacteria, and subsequent biological denitrification consumes nitrate, ammonium and other components of the system^[20–21]. Therefore, the freshness of the pulp solution is highly correlated with changes in volatile fatty acids and nitrates in the pulp system^[22–24]. The determination of acid radical ions in aqueous solutions is mostly performed by ion chromatography. Most of the traditional solid-phase extraction (SPE) has the following disadvantages: manual operation is mostly performed with a negative pressure vacuum extraction device, the flow rate is difficult to control accurately, and the flow rate has a large impact on the recovery. Sample pre-treatment usually uses a variety of harmful organic solvents, and the pre-treatment of multiple batches of samples is time-consuming^[25]. Fully automated SPE systems are increasingly favoured by the majority of laboratory workers because of their advantages of high sample throughput, high work efficiency, good reproducibility and safety.

In the present study, we investigated the variation patterns of organic and inorganic acids in reconstituted tobacco pulp with residence time and the changes of isovaleric acid and nitrate content during the deterioration process of reconstituted tobacco slurry under sealed conditions in combination with sensory quality evaluation. Recombinant tobacco slurry contains inorganic salts, polysaccharides, proteins, pigments, metal ions, aromatic substances, organic small molecules and other substances, and the sample environment is complex. The contents of 17 organic acids and 5 inorganic anions in recombinant tobacco slurries with different closed retention times were determined by ion chromatography coupled with on-line solid phase extraction and regeneration.

2.1 Materials.

The compounds used - sodium formate, sodium acetate, sodium propionate, sodium butyrate, sodium valerate, sodium pyruvate, sodium caproate, sodium sulphate, sodium chloride, potassium dihydrogen phosphate - were obtained from the China National Institute for the Control of Pharmaceutical and Biological Products (Beijing, China). The compounds used - sodium lactate, sodium isobutenoate, sodium isovalerate, sodium 3-methylpentanoate, sodium 4-methylpentanoate, sodium benzoate, sodium tartrate, sodium oxalate, sodium malate, sodium citrate, sodium nitrate solution, nitrous acid - were purchased from Dr. Ehrenstorfer (GmbH, Germany).HPLC grade acetonitrile was purchased from Merck (Darmstadt, Germany). Ultrapure water for mobile phases and analytical stock solutions was generated by Milli-Q Water Purification System (Millipore, Bedford, MA, USA).Workshop pulp for T-1, T-2, and T-3 recombinant tobacco filaments was supplied by Henan Cigarette Industrial Reconstituted Tobacco Sheet Co., Ltd.

2.1.1 Standard solutions

An appropriate amount of standard substance was accurately weighed to 0.1 mg, and a single reserve aqueous solution of sodium organic acid and inorganic acid ions at a concentration of 1.00 mg/mL was prepared. Remove the standard reserve aqueous solution and prepare a mixed standard solution at a concentration of 100 mg/L. Working solutions containing all analytes were prepared at concentrations of 10.00, 9.00, 8.00, 7.00, 6.00, 5.00, 4.00, 3.00, 2.00, 1.00, 0.50, 0.10, and 0.05 mg/litre, respectively. All solutions were prepared at 4°C and stored in polypropylene containers. All containers were rinsed twice with purified water before use.

2.1.2 Sample Preparation

Workshop slurries of recombinant tobacco (T1, T2, and T3, with a slurry concentration of approximately 3%) were shaken well, and 100 mL of the slurries were placed into 250 mL grinding flasks to seal a total of 26 samples, which were placed in a thermostatic incubator at 50°C and a constant speed of 120 r/min. Two samples were taken as parallel samples every one hour, and then 100 µL of sodium hydroxide in aqueous (4 mol/L) was added immediately, shaken well, and the sample preparation was completed. Then 100 µL of aqueous sodium hydroxide solution (4 mol/L) was immediately added, shaken well, and centrifuged at 12000 r/min for 10 min. The supernatant was passed through a 0.22 µm needle filter, and the filtrate was stored in a refrigerator at 4 ℃ for analysis.

2.1.3 Separation process

The IC system and components were obtained from Thermo Fisher (Dionex, USA). The steps of the analysis process are shown in Fig. 1). The sample is automatically injected into the 25 µL quantitation ring (valve 2). 2) The sample is carried by pure water to the Na-type solid phase extraction column, where the heavy and transition metal ions are trapped on the Na column. After the metal ions are removed by the Na column, the entire sample enters the large quantitation ring and the AG11-HC pretreatment column (concentrator). 3) The sample is then analyzed by the Na-type solid phase extraction column. 4) The sample is then analyzed by the Na-type solid phase extraction column. 5) The sample is then analyzed by the Na column. The hydrophobic material in the sample matrix is retained on the AG11-HC column, while the negative ions are not retained and enter the subsequent AS11-HC ion exchange column (Valve 1).3) Acetonitrile rinses the sample matrix retained on the anionic preconditioning column into the waste stream, allowing for the cleaning and regeneration of the AG11-HC column (Valve 1).4) The measured components are rinsed with the eluate to the AS11-HC analyser column, which passes through the suppressor and into the electrophoresis column. column, through the suppressor, and into the conductivity detector.

2.1.4 On-line pre-treatment conditions

On-line concentration and purification of samples were performed on a Dionex ICS-6000 using a DionexInGuardTM Na SPE column (Thermo Fisher) with an internal diameter of 9 × 24 mm and a DionexIonPac AG11-HC column (Thermo Fisher) with an internal diameter of 4 × 50 mm. Mobile phases A and B were deionised water and acetonitrile, respectively. The on-line pretreatment conditions and valve switching times are shown in Table 1.

Table 1

On-line pretreatment conditions and valve switching time
Time/min	Initial	-0.85	0	1	1	8	8	50	50	63	63	65
A/%	100	100	100	100	0	0	0	0	100	100	100	100
B/%	0	0	0	0	100	100	100	100	0	0	0	0
Flow rate /(mL/min)	1	1	1	1	1	1	0.2	0.2	0.2	0.2	1	1
Valve 1	load	load	inject	inject	load	load	load	load	load	load	load	load
Valve 2	load	inject	inject	inject	inject	inject	inject	inject	inject	inject	inject	inject

2.1.5 Ion Chromatograph Conditions

The hardware consisted of an ICS-6000 IC system equipped with a gradient pump, an ED160 mA conductivity detector, and a high-capacity anion-exchange analytical column (IonPac AS11-HC, 250 mm × 4 mm). All experiments were carried out at a flow rate of 1.5 ml/min and an oven temperature of 30°C. The cuvette temperature was 35°C. The sample temperature was set at 1.5 ml/min. The cuvette temperature was 35°C and the injection volume was 25 µl (full cycle). The mobile phase KOH solution was generated by an ADRS600 automatic on-line electrolyte eluent generator (Thermo Fisher). The separation was completed within 65 min according to the gradient elution profile. 0.8 mmol/L KOH solution concentration was maintained for 15 min, rising to 4.0 mmol/L in 8 min, 8 mmol/L in 1 min and maintained for 23 min, 45 mmol/L in 5 min and maintained for 7 min, and falling to 0.8 mmol/L in 1 min and maintained for 2 min.

2.1.6 Preparation of Sensory Evaluation Samples

The pulp at 3% consistency was made into paper at 100°C and − 0.9 kPa using the "rapid-koethen" system (ESTANIT, Germany).

2.1.7 Sniffing method

Sniffing was carried out when the conical flasks were opened. According to the process monitoring method, the first 5 hours were the critical testing period and tests were performed every 1 hour. The olfactory characteristics included 11 indicators such as Virginia tobacco aroma, sun tobacco aroma, freshness aroma, fruit aroma, roasted aroma, sweet aroma, woody, stemmy, dry yeast, fatty acid spoilage and mouldy.

3.1 Variation of acid radical ion content in slurry with residence time.

Most of the water used in the pulping process is recycled water from the pulping system during RTS production. The recycled water is rich in starch, inorganic salts, polysaccharides and other chemical components, and also accumulates metabolic by-products such as lactic acid, formic acid, acetic acid and isovaleric acid. As a result, the concentrations of lactic acid, formic acid, acetic acid, isovaleric acid, tartaric acid, chloride ions, sulfate ions, phosphate ions, and citrate ions in the mud are much higher than those of other organic acids (e.g., butyric acid, valeric acid, hexanoic acid, etc.).

High concentrations of lactic acid, acetic acid, formic acid, etc. result in poor chromatographic peak shapes and quantitative accuracy if the sample is not diluted. In order to achieve accurate quantification, the samples were diluted in different ratios according to the different concentrations of lactic acid, acetic acid and formic acid. The concentration of acid ions was plotted as a function of residence time (Fig. 2).

The results showed that when the recombinant tobacco slurry was placed in an incubator at 50 ℃, the concentrations of isovaleric acid and valeric acid in the recombinant tobacco slurry firstly increased and then gradually decreased with the prolongation of the residence time, in which the concentration of isovaleric acid reached the maximum value at the residence time of 3 h, and then there was no obvious change after 9 h. The concentration of valeric acid reached the maximum value at the residence time of 9 h, and then gradually decreased. The concentration of pyruvic acid did not change significantly within 5 h of mud retention, and then increased gradually, and did not change significantly after 7 h. The concentrations of acetic acid, tartaric acid and formic acid increased gradually with the increase of slurry residence time, and the content of acetic acid did not change significantly after 6 h of residence. The concentrations of nitrite ion and nitrite ion in the slurry did not change significantly within 3 h of residence time, and then decreased sharply after 4–5 h of residence time, after which there was no significant change. The concentration of benzoic acid in the slurry decreased gradually with the prolongation of retention time, and the concentration decreased sharply after 6–7 h, and then there was no obvious change. The concentrations of lactic acid, phosphoric acid, citric acid and propionic acid in the slurry decreased gradually with the extension of residence time, while the concentration of 4-methylpentanoic acid did not change significantly during the residence time of 8h, and then decreased gradually. The content of oxalic acid in the slurry changed irregularly with the increase of residence time, while the concentrations of butyric acid, sulphate, chloride and malic acid in the slurry did not change significantly with the increase of residence time.

The reconstituted tobacco slurry was operated in a closed pipe, and the anaerobic bacteria in the slurry underwent two stages of hydrolytic acidification and denitrification reactions during anaerobic digestion. In the hydrolytic acidification reaction stage, the concentration of some organic acids gradually increased, and some acids, nitrate ions and nitrate ions were consumed in the denitrification reaction stage ^[24]. The above analyses showed that the concentrations of acetic acid, isovaleric acid, valeric acid, pyruvic acid, benzoic acid, nitrate ions and nitrite ions in the slurry changed regularly with the prolongation of the residence time, and the contents of isovaleric acid, nitrite ions and nitrate ions began to decrease sharply after 4 h of residence.

3.2 Correlation analysis of the trends of acid ions in different slurries with residence time

The concentrations of acetic acid, isovaleric acid, valeric acid, pyruvic acid, benzoic acid, nitrate ion and nitrite ion in the recombinant tobacco slurries changed significantly with increasing residence time.

Valeric acid and nitrite ions were not detected in some slurries. Therefore, only the concentrations of acetic acid, isovaleric acid, pyruvic acid, benzoic acid and nitrate ions in different brands of reconstituted tobacco slurries (T1, T2 and T3) were correlated with the increase in residence time, and the results are shown in Table 2.

The results showed that with the extension of residence time, the trends of acetic acid content in T1, T2 and T3 pulps showed highly significant positive correlation (P༜0.01) with the trends of acetic acid content in T1, T2 and T3 pulps, respectively, and the trends of acetic acid content in T2 and T3 pulps showed highly significant positive correlation (P༜0.01) with the trends of acetic acid content in T1, T2 and T3 pulps, respectively. .

The trends of isovaleric acid content in T1 and T3 pulps with residence time were highly significantly correlated (P < 0.01), and the trends of isovaleric acid content in T1 and T2 pulps were significantly correlated (P < 0.05).There was no significant correlation between the trends of isovaleric acid content in T2 pulp and T3 pulp.

Table 2

Correlation analysis of changes of acetic acid, iso-valerate and nitrate ion in different pulps during oscillation①
		acetic acid			iso-valerate			nitrate ion
		T1	T2	T3	T1	T2	T3	T1	T2
acetic acid	T2	0.919**	1
acetic acid	T3	0.889**	0.940**	1
iso-valerate	T1	-0.718**	-0.765**	-0.831**	1
	T2	0.045	-0.191	-0.301	0.578*	1
	T3	-0.734**	-0.678*	-0.749**	0.897**	0.453	1
nitrate ion	T1	-0.871**	-0.700*	-0.744**	0.756**	0.032	0.894**	1
	T2	-0.913**	-0.813**	-0.825**	0.805**	0.162	0.911**	0.962**	1
	T3	-0.868**	-0.884**	-0.931**	0.940**	0.438	0.913**	0.843**	0.923**
Note: ①* represents significant correlation (P < 0.05), and ** represents extremely significant correlation (P < 0.01).

The trends of nitrate ion content in T1 pulp, T2 pulp and T3 pulp were highly significantly and positively correlated (P < 0.01) with the trends of nitrate ion content with residence time, and the trends of nitrate ion content in workshop T2 pulp and T3 pulp were highly significantly and positively correlated (P < 0.01). The trend of nitrate ion content in workshop pulp was highly significantly correlated with the trend of acetic acid content (P < 0.01), and highly significantly correlated with the trend of isovaleric acid content in workshop T1 pulp and T3 pulp (P < 0.01).

3.3 Changes in aroma style of sheet base prepared from pulp with different dwell times

Fresh reconstituted tobacco pulps of T-1 and T-2 and pulps with different residence times were prepared according to the method of sensory evaluation sample preparation. After equilibrium, the samples were evaluated according to the visual sensory evaluation method, and the results are shown in Fig. 3.

The results showed that the fresh pulps of TS-2 and ZY-2 were mainly characterised by virgin tobacco, fruity and sweet aromas, and the tobacco, fruity and sweet aromas gradually diminished with the increase of pulp residence time. In TS-2 and ZY-2 recombinant tobacco flake bases, the xylem odour gradually decreased and the stem odour gradually appeared with the prolongation of the pulping oscillation time.

In the TS-2 slurry, the dry yeast odour and the fatty acid degradation odour appeared after 5 hours of oscillation, and the aroma of the recombinant tobacco tablets after 7 hours was unchanged compared with that at 5 hours. The tablet base prepared from ZY-2 slurry showed dry yeast odour and small amounts of fruity and sweet aroma after 6 hours of shaking. Tablets prepared from TS-2 ZY-2 slurry showed a slight increase in dry yeast odour after 9 hours of shaking, but no fruity or sweet notes.

3.4 Changes of isovaleric acid and nitrate ions in reconstituted tobacco pulp during closed oscillation process

In the process of remanufactured tobacco flaking, most of the water used for pulping is recycled water, which contains a large amount of starch, inorganic salts, polysaccharides, and other components such as volatile fatty acids. The organic and inorganic acid ion contents of different reconstituted tobacco pulps were determined by on-line solid phase extraction (SPE) ion chromatography during 12 h of oscillation. Isovaleric acid and nitrate ions, which varied regularly with oscillation time, were further determined.

Table 3

Contents of iso-valeric acid and nitrate ions in different pulp
oscillation time	nitrate ions (mg/L)				Iso-valeric acid (mg/L)
(h)	TS-1	TS-2	ZY-1	ZY-2	TS-1	TS-2	ZY-1	ZY-2
0	94.98	110.53	110.56	102.56	338.59	186.83	457.02	523.63
1	128.61	109.21	111.79	101.27	408.85	190.24	750.53	869.52
2	158.73	114.55	113.47	103.81	437.61	258.87	836.4	901.23
3	151.68	114.9	115.02	104.92	558.39	552.14	890.94	1010.1
4	83.37	98.03	113.36	97.56	446.76	1129.38	921.65	1115.6
5	1.02	20.84	79.13	70.01	403.22	836.98	381.2	456.52
6	1.98	17.42	52.67	53.14	313.71	691.6	288.34	356.45
7	5.13	18.34	32.65	30.13	241.77	326.94	247.71	268.29
8	5.31	13.47	11.97	13.42	161.3	193.22	203.32	234.12
9	9.33	13.12	5.01	6.26	95.69	154.02	164.66	153.26
10	11.52	9.06	5.94	5.32	83.05	149.68	153.88	142.15
11	1.44	4.47	5.91	5.75	75.51	147.94	131.72	123.21
12	6.48	0.29	4.45	2.61	79.28	91.28	135.57	122.01

Table 3 shows the content of isovaleric acid and nitrate ions in different reconstituted tobacco pulps. Table 3 shows the contents of isovaleric acid and nitrate ions in different recombinant tobacco pulps. It can be found that the content of isovaleric acid in the pulps increased gradually and then decreased sharply with the extension of the oscillation time. the content of isovaleric acid in the TS-1 pulp decreased sharply in the oscillation cycle of 3–9 h, while the content of isovaleric acid in the TS-2, ZY-1 and ZY-2 pulps decreased sharply in the oscillation cycle of 4–5 h. The results showed that the isovaleric acid and nitrate ion contents in the different recombinant tobacco pulps were significantly lower than those in the TS-2, ZY-1 and ZY-2 pulps. The nitrate ions in different recombinant tobacco pulps showed obvious regular changes during 3–4 h of oscillation, so nitrate ions were chosen as the characteristic components for the characterisation of pulp freshness.

3.5 Percentage changes of isovaleric acid and nitrate ions in recombinant tobacco pulps during closed oscillations

Table 4 summarises the percentage changes of isovaleric acid and nitrate ions in different pulps with oscillation time relative to their fresh pulp. Table 4 (Fresh pulp is the operating pulp freshly prepared in the workshop). The results showed that the nitrate ion content in TS-1 and TS-2 pulps decreased by about 80–98% after 5 h of closed oscillation, and the nitrate ion content in ZY-1 and ZY-2 pulps decreased by about 50% after 6 h of closed oscillation. The isovaleric acid content in ZY-1 and ZY-2 pulps decreased by about 12–16% after 5 h of closed shaking, and decreased by about 7% in TS-1 pulp after 6 h of shaking and by about 17% in TS-2 pulp after 9 h of shaking. After about 6 h of pulp shaking, the nitrate ion content in the pulp decreased by more than 50% compared to fresh pulp of reconstituted tobacco. Therefore, a 50% change in nitrate content can be used as a characteristic value for pulp freshness characterisation.

Table 4

Percentage change of isovaleric acid and nitrate ions in different pulps with oscillation time relative to their fresh sizes
oscillation time	nitrate ions (%)				iso-valeric acid (%)
(h)	TS-1	TS-2	ZY-1	ZY-2	TS-1	TS-2	ZY-1	ZY-2
1	35.41	-1.19	1.11	-1.26	20.75	1.83	64.22	66.06
2	67.12	3.64	2.63	1.22	29.25	38.56	83.01	72.11
3	59.70	3.95	4.03	2.30	64.92	195.53	94.95	92.91
4	-12.22	-11.31	2.53	-4.88	31.95	504.50	101.67	113.05
5	-98.93	-81.15	-28.43	-31.74	19.09	347.99	-16.59	-12.82
6	-97.92	-84.24	-52.36	-48.19	-7.35	270.18	-36.91	-31.93
7	-94.60	-83.41	-70.47	-70.62	-28.60	74.99	-45.80	-48.76
8	-94.41	-87.81	-89.17	-86.91	-52.36	3.42	-55.51	-55.29
9	-90.18	-88.13	-95.47	-93.90	-71.74	-17.56	-63.97	-70.73
10	-87.87	-91.80	-94.63	-94.81	-75.47	-19.88	-66.33	-72.85
11	-98.48	-95.96	-94.65	-94.39	-77.70	-20.82	-71.18	-76.47
12	-93.18	-99.74	-95.98	-97.46	-76.59	-51.14	-70.34	-76.70

3.6 Changes in the odour style of recombinant tobacco pulp with oscillation time

According to the method of evaluation of appearance and sensory quality, the pulp samples prepared from TS-2 pulp in the production workshop with different oscillation times were evaluated, and the odour aroma styles of the pulps within 7 h of oscillation were plotted, and the results are shown in Fig. 4. The results showed that the fresh pulps of TS-2 and ZY-2 mainly exhibited the characteristics of Virginia tobacco aroma, fruity aroma and sweet aroma, and these aromas gradually weakened with the extension of the oscillation time. At 5 h of oscillation, the pulp of TS-2 showed dry yeast smell and fatty acid failure, and at 7 h of oscillation, there was almost no fruity and sweet smell and only a little mouldy smell; at 6 h of oscillation, the pulp of ZY-2 had almost no fruity and sweet smell, and at 7 h of oscillation, there was almost no fruity and sweet smell, but only a little mouldy smell; at 7 h, there was a dry yeast smell and fatty acid failure, and at 9 h, there was a slight mouldy smell, in addition to the dry yeast smell and fatty acid failure. At 9 h, in addition to the dry yeast odour and the fatty acid scum, there was also a slight mouldy odour.

3.7 Effects of pulping oscillation time on the aroma style of reconstituted tobacco flakes

Fresh pulp of TS-2 and ZY-2 and pulp with different pulping oscillation times were prepared according to the method of sensory evaluation sample preparation. After equilibration, the samples were evaluated according to the visual sensory evaluation method.

As can be seen in Fig. 5, the tobacco aroma, fruity aroma and sweet aroma of the TS-2 and ZY-2 restored tobaccos gradually decreased with the increase of pulp oscillation time, and the results were consistent with those in Fig. 4. In TS-2 and ZY-2 recombinant tobacco flakes, the xylem odour gradually decreased and the stem odour gradually appeared with the extension of pulp oscillation time. At 5 h of oscillation, the matrix of TS-2 pulp began to show dry yeast odour and fatty acid defeat, and the aroma of recombinant tobacco flakes at 7 h was unchanged compared with that at 5 h. At 6 h of oscillation, dry yeast odour and a small amount of fruity-sweet aroma appeared in the flakes of ZY-2 pulp, and the dry yeast odour of the matrix of ZY-2 pulp was slightly increased but no fruity-sweet aroma was present at 9 h of oscillation.

3.8 Variation of characteristic styles of recombinant tobacco flakes with pulping oscillation time

The prepared pulp flake base samples were evaluated according to the sensory evaluation method and the results are shown in Fig. 6. The results showed that the oral irritation/tongue burning sensation, oral mucous membrane/dryness sensation and nasal irritation of the reconstituted tobacco flakes tended to increase with the increase of pulping and oscillation time, the aroma amount tended to decrease, and the smoke density, richness and smoothness/softness/mellowness tended to decrease. There was no change in oral irritation/tongue burning, oral mucous membrane/dryness and nasal irritation of TS-2 recombinant tobacco flakes after 5 hours of swinging. After 7 h of oscillation, the smoke density of TS-2 flakes increased slightly, which might be due to the microbial decomposition of proteins and starch. There was no significant change in the richness and smoothness/softness/mellowness of ZY-2 recombinant tobacco flakes after 6 h of oscillation, and the smoke density of ZY-2 recombinant tobacco flakes did not change significantly during 9 h of oscillation.

The above analyses showed that the sensory quality of TS-2 and ZY-2 pulp decreased significantly after 5 or 6 hours of oscillation, mainly in terms of decreased aroma, increased odour, increased irritation and poor oral comfort. According to the production experience, the pulp was judged to be unqualified.

3.9 Determination of indexes of reconstituted tobacco fresh pulp

The content of nitrate ions in TS-1 and TS-2 pulps did not change much during the 3-h oscillation cycle, but decreased sharply during the 4-h to 5-h oscillation cycle, and the content of nitrate ions in ZY-1 and ZY-2 pulps did not change much during the 4-h oscillation cycle, but decreased sharply during the 5-8-h oscillation cycle. The nitrate ion content in TS-1 and TS-2 pulps decreased by about 80–98% after 5 h of closed oscillation, and the nitrate ion content in ZY-1 and ZY-2 pulps decreased by about 50% after 6 h of closed oscillation. With the prolongation of the oscillation time, the isovaleric acid content in TS-0006, TS-0002 and ZY-02 pulps gradually increased and then decreased, reaching the highest value at 4 h of oscillation.

According to the correlation analysis of the changes of isovaleric acid and nitrate ions, the trend of nitrate ions in TS-1 pulp was significantly correlated with that in TS-2, ZY-1 and ZY-2 pulp (P < 0.01), respectively, and the trend of isovaleric acid in TS-1 pulp was significantly positively correlated with that in TS-2 pulp (P < 0.05), whereas the trend of isovaleric acid in TS-2 pulp was significantly positively correlated with that of TS-0006, TS-0002 and ZY-02 pulp (P < 0.05), whereas that of TS-2 pulp was significantly positively correlated with that of TS-0006, TS-0002 and ZY-02 pulp (P < 0.05). ), while the trend of isovaleric acid content in TS-2 pulp was not significantly positively correlated with the trend of isovaleric acid content in ZY-2 pulp in the workshop.

After 5 h and 6 h of oscillation, the sensory quality of TS-2 and ZY-2 pulp in the workshop decreased significantly, mainly in terms of decreased aroma, increased odour, increased irritation, and poor oral comfort. This is consistent with the change rule of nitrate ions in pulp with oscillation time. The sensory quality of TS-1 and ZY-1 sizing was analysed by the same method, and the results were consistent with the sensory evaluation results of TS-2 and ZY-2 sizing.

Therefore, nitrate ions in pulp were chosen to be monitored as the characteristic ions to characterise pulp freshness. When the nitrate ion content of reconstituted tobacco pulp was reduced by about 50% compared to fresh pulp, it indicated that the pulp was not usable. This helps to monitor the quality of reconstituted tobacco pulp and ensure the stability of the quality of reconstituted tobacco products.

The sample matrix of the reconstituted tobacco pulp was complex and an on-line purification process was established. The contents of 17 organic acids and 5 inorganic anions in the reconstituted tobacco pulp with different closed retention times were determined by ion chromatography using an on-line solid phase extraction (SPE) column, anion pretreatment and concentration column, a valve switching technique and a regenerative purification column.

The results showed that the content of acetic acid in T1, T2 and T3 pulps increased gradually with the increase of residence time, and then there was no obvious change trend. The content of isovaleric acid in pulp increased gradually with the increase of residence time, and then decreased gradually, and reached the highest value at the residence time of 3 h or 4 h. The content of isovaleric acid in T1 pulp decreased rapidly during the residence time of 3–9 h, and then showed no obvious change after 9 h. The content of isovaleric acid in T2 and T3 pulp decreased sharply during the residence time of 4–5 h, and then decreased gradually after 5 h, with no obvious trend of change. The content of nitrate ions in T3 pulp did not change significantly within 4 h, and then decreased sharply within 4–8 h, and then did not change significantly. The content of nitrate ions in T1 pulp increased gradually within 2 h, and then decreased sharply within 3–5 h, and then did not change significantly.

Nitrate ion content in T1, T2 and T3 pulps showed a highly significant positive correlation with residence time (P < 0.01), and isovaleric acid content in T1 and T3 pulps showed a highly significant positive correlation with residence time (P < 0.01).

The anaerobic bacteria in the pulp produced dissolved organic compounds and volatile fatty acids during anaerobic hydrolysis/acidification, so the content of acetic acid and isovaleric acid gradually increased during the residence process. Denitrification occurs during anaerobic digestion by anaerobic bacteria [13], and these volatile fatty acids can provide a carbon source for biological denitrification, and at the same time, the denitrification process consumes nitrate, ammonium salts and other components contained in the system. As a result, the content of isovaleric acid and nitrate ions in the pulp decreases with increasing residence time.

During the production of reliquefied tobacco, the pulp is usually run in closed pipes for no more than 5 h. The organic acids and inorganic anions vary slightly with the season and the temperature of the plant. Isovaleric acid and nitrate were selected as the characteristic components of pulp for monitoring to support the use of pulp in production.

The nitrate ion content in TS-1 and TS-2 pulps decreased by about 80–98% after 5 h of closed shaking, and the nitrate ion content in ZY-1 and ZY-2 pulps decreased by about 50% after 6 h of closed shaking. There was a significant correlation between the content of nitrate ions in different pulps and the oscillation time. The changes of nitrate ion content in pulp with oscillation time were consistent with the changes of olfactory and sensory quality of pulp with oscillation time. Based on the production of reconstituted tobacco, nitrate ions in pulp were chosen to be monitored as the characteristic ions characterising pulp freshness. When the nitrate ion content of reconstituted tobacco pulp decreased by about 50% compared to fresh pulp, it indicated that the pulp was no longer fresh and should not be used.

Compliance with ethical standards: The authors adhered to ethical standards.

Conflict of interest: The authors declare that they have no conflicts of interest.

Ethical approval: No studies involving human participants or animals were conducted.

Acknowledgments: The authors acknowledge the financial support from Henan Tobacco Industry Co., LTD (Yuyan Technology [2020] No. 13)

STATEMENT OF DATA AVAILABILITY

All data generated or analysed during this study are included in this published article.

Boya Luo, Xingye An, Jian Yang, et al. Isolation and utilization of tobacco-based cellulose nanofiber (TCNF) for high performance reconstructed tobacco sheet (RTS). Carbohydrate Polymers, 2021, 261, 117865.
Haoyue Liu, Zhong Liu, Hongbin Liu, et al. Using cationic nanofibrillated cellulose to increase the precipitated calcium carbonate retention and physical properties during reconstituted tobacco sheet preparation. Industrial Crops and Products, 2019, 130, 592–597.
Maoshen Chen, Zhiqiang Xu, Gang Chen,et al. The influence of exogenous fiber on the generation of carbonyl compounds in reconstituted tobacco sheet. Journal of Analytical and Applied Pyrolysis, 2014, 105, 227–233.
Jiarui Li, Jing Hu, Shanshan Li, et al. The effect of guar gum and chitosan on fiber and fiber fine micromorphology in paper-process reconstituted tobacco pulp. Carbohydrate Polymers, 2018, 196, 102–109.
Wenhua Gao, Kefu Chen. Physical properties and thermal behavior of reconstituted tobacco sheet with precipitated calcium carbonate added in the coating process. Cellulose, 2017, 24, 2581–2590.
Chen, MS, Xu, ZQ, Chen, G, Wang, H, Yin, CY, Zhou, ZL, Sun WF, Li Y, Zhong F. The influence of exogenous fiber on the generation of carbonyl compounds in reconstituted tobacco sheet. Journal of Analytical and Applied Pyrolysis. 2014; 105: 227–233.
Nakagaito AN, yano H. The effect of morphological changes from pulp fiber towards nano-scale fibrillated cellulose on the mechanical properties of high-strength plant fiber based composites. Applied Physics A. 2004; 78: 547–552.
Veluchamy, C., Kalamdhad, A.S. Biochemical methane potential test for pulp and paper mill sludge with different food / microorganisms ratios and its kinetics. International Biodeterioration & Biodegradation. 2017; 117:197–204..
Amani T, Nosrati M, Mousav SM. Response surface methodology analysis of anaerobic syntrophic degradation of volatile fatty acids in an upflow anaerobic sludge bed reactor inoculated with enriched cultures. Biotechnology and Bioprocess Engineering. 2012; 17:133–144.
Amani T, Nosrati M, Mousavi SM, Elyasi S. Study of microbiological and operational parameters in thermophilic syntrophic degradation of volatile fatty acids in an upflow anaerobic sludge blanket reactor. Journal of Environmental Chemical Engineering. 2015; 3: 507–514.
Zhu ZH, Guo YY, Zhao YC, Zhang RN, Yu Y, Zhang ML, Zhou T. Sewage denitrification performance and sludge properties variation with the addition of liquid from perishable organic anaerobic fermentation. Bioresource Technology. 2021; 341: 125821.
Wang L, Chen LD, Wu S, Ye JF. Non-airtight fermentation of sugar beet pulp with anaerobically digested dairy manure to provide acid-rich hydrolysate for mixotrophic microalgae cultivation. Bioresource Technology. 2019; 278: 175–179.
Veluchamy C, Kalamdhad AS. Influence of pretreatment techniques on anaerobic digestion of pulp and paper mill sludge: A review. Bioresource Technology. 2017; 245: 1206–1219.
Wahia H, Zhou CS, Mustapha AT, Amanor-Atiemoh R, Mo L, Fakayode OA, et al. Storage effects on the quality quartet of orange juice submitted to moderate thermosonication: Predictive modeling and odor fingerprinting approach. Ultrasonics - Sonochemistry 2020; 64: 104982.
Ren LY, Ma J, Lv Y, Tong QG, Guo HY. Characterization of key off-odor compounds in thermal duck egg gels by GC-olfactometry-MS, odor activity values, and aroma recombination. LWT - Food Science and Technology 2021; 143: 111182.
Venugopal V. Biosensors in fish production and quality control. Biosens. Bioelectron. 2002, 17: 147–157.
Tantayotai P, Pornwongthong P, Muenmuang C, Phusantisampand T, Sriariyanun M. Effect of Cellulase-producing Microbial Consortium on Biogas Production from Lignocellulosic Biomass. Energy Procedia 2017; 141: 180–183.
Shao Y, Xia MJ, Liu J, Liu XY, Li ZS. Composition and profiles of volatile organic compounds during waste decomposition by the anaerobic bacteria purified from landfill. Waste Management 2021; 126: 466–475.
Sawayama S, Tsukahara K, Yagishita T. Organic acid consumption of phototrophic bacteria in a lighted upflow anaerobic sludge blanket reactor. J. Biosci. Bioeng. 2000; 90: 241–246.
Wang L., Chen LD, Wu S, Ye JF. Non-airtight fermentation of sugar beet pulp with anaerobically digested dairy manure to provide acid-rich hydrolysate for mixotrophic microalgae cultivation. Bioresource Technology 2019; 278:175–179.
Veluchamy C., Kalamdhad A. Influence of pretreatment techniques on anaerobic digestion of pulp and paper mill sludge: A review. Bioresource Technology 2017; 245: 1206–1219.
Doreya S, Gastona F, Dupuyb N, Barbaroux M, Marque SRA. Reconciliation of pH, conductivity, total organic carbon with carboxylic acids detected by ion chromatography in solution after contact with multilayer films after γ-irradiation. European Journal of Pharmaceutical Sciences. 2018; 117: 216–226.
Zhong YY, Zhou WF, Hu ZZ, Chen ML, Zhu Y. Novel additives for the separation of organic acids by ion-pair chromatography. Chinese Chemical Letters. 2010; 21: 453–456.
Shelor CP, Dasgupta PK. Automated programmable pressurized carbonic acid eluent ion exclusion chromatography of organic acids. J. Chromatogr. A. 2017; 1523: 300.
Zhang C, Xing HF, Yang LR, Fei PF, Liu HZ. Development trend and prospect of solid phase extraction technology. Chinese Journal of Chemical Engineering. 2021; 2333.

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Characterising the change rule of freshness and inorganic anions in reconstituted tobacco pulp with oscillation time

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Abstract

Figures

1 Introduction

2 Materials and Methods

2.1 Materials.

2.1.1 Standard solutions

2.1.2 Sample Preparation

2.1.3 Separation process

2.1.4 On-line pre-treatment conditions

2.1.5 Ion Chromatograph Conditions

2.1.6 Preparation of Sensory Evaluation Samples

2.1.7 Sniffing method

3 Results and Discussion

3.1 Variation of acid radical ion content in slurry with residence time.

3.2 Correlation analysis of the trends of acid ions in different slurries with residence time

3.3 Changes in aroma style of sheet base prepared from pulp with different dwell times

3.4 Changes of isovaleric acid and nitrate ions in reconstituted tobacco pulp during closed oscillation process

3.5 Percentage changes of isovaleric acid and nitrate ions in recombinant tobacco pulps during closed oscillations

3.6 Changes in the odour style of recombinant tobacco pulp with oscillation time

3.7 Effects of pulping oscillation time on the aroma style of reconstituted tobacco flakes

3.8 Variation of characteristic styles of recombinant tobacco flakes with pulping oscillation time

3.9 Determination of indexes of reconstituted tobacco fresh pulp

4 Conclusion

Declarations

References

Additional Declarations

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