Changes in volatile compounds, sugars and organic acids of different spices of peppers (Capsicum annuum L.) during storage

Journal Pre-proofs Changes in volatile compounds, sugars and organic acids of different spices of peppers (Capsicum annuum L.) during storage Aziz Korkmaz, Ahmet Ferit ATASOY, Ali Adnan Hayaloglu PII: DOI: Reference:

S0308-8146(19)32048-5 https://doi.org/10.1016/j.foodchem.2019.125910 FOCH 125910

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Food Chemistry

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1 June 2019 20 October 2019 13 November 2019

Please cite this article as: Korkmaz, A., Ferit ATASOY, A., Adnan Hayaloglu, A., Changes in volatile compounds, sugars and organic acids of different spices of peppers (Capsicum annuum L.) during storage, Food Chemistry (2019), doi: https://doi.org/10.1016/j.foodchem.2019.125910

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1

Changes in volatile compounds, sugars and organic acids of different spices of peppers

2

(Capsicum annuum L.) during storage

3 4

Aziz Korkmaza,*, Ahmet Ferit ATASOYb,c, Ali Adnan Hayaloglud

5

a

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University, 47200, Mardin, Turkey

7

b

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Sanlıurfa, Turkey

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c

Faculty of Health Science, Department of Nutrition and Dietetics, Mardin Artuklu

Faculty of Engineering, Department of Food Engineering, Harran University, 63010,

Pepper and Isot Research and Application Center, Harran University, 63010, Sanlıurfa,

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Turkey

11

d

12

Turkey

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*

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Artuklu University, 47200, Mardin, Turkey

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E-mail: [email protected]

Faculty of Engineering, Department of Food Engineering, Inonu University, 44000, Malatya,

Corresponding author: Health College, Department of Nutrition and Dietetics, Mardin

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Abstract

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Changes in sugars, organic acids and volatile compounds (VC) of red pepper flakes (RPF),

19

traditional (TRI), and industrial (INI) isot peppers were evaluated during one year storage at

20

the room condition. The changes in the flavor components were significantly affected by the

21

production methods and storage time. Glucose content decreased gradually along storage and

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reduced by about 21.23, 47.22 and 56.65% for TRI, INI and RPF, respectively. However,

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fructose decreased significantly only in RPF (11.29%). Citric and succinic acids exhibited

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slight changes, but malic acid showed an increasing trend, especially in RPF (4-fold). Most of

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the VC in all samples decreased or disappeared after storage. The major quantitative losses in

1

26

in these compounds were found in TRI during the first 3 months as 81.76%. The storage was

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found to be caused deterioration flavor properties in red pepper spices and revealed the

28

importance of appropriate storage conditions.

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Keywords: Red pepper, isot pepper, flavor changes, red pepper flakes, sugar and organic

31

acids, volatiles profile

32 33

1. Introduction

34

Dried red pepper (Capsicum annuum L.) is one of the most consumed spices in the world. It is

35

widely used in both food industry and different cuisines because of its color, pungency and

36

flavor. In addition to organoleptic significance, peppers have beneficial effects on human

37

health due to their high antioxidant contents and bioactive constituents (Liu, 2003).

38

There are various forms of dried red Capsicum and its products in the world, but the grinded

39

ones are the most often used types. In Turkey, red pepper flakes and isot pepper are the main

40

kinds of produced and consumed ground spices of this genus. Isot, a typical spice of Turkish

41

cuisine, is blackish red colored and crushed dried pepper. The largest amount of these spices

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in the country is obtained from southeast region. This area has a suitable climatic condition

43

for cultivation and certain productions, such as long sunny days for sunlight drying. Isot

44

pepper is produced from local Capsicum varieties and can be obtained by both traditional and

45

industrial methods (Korkmaz, Hayaloglu & Atasoy, 2017). Particularly, traditional isot is

46

among the most popular spices in Turkey for its unique flavor and a reddish purple color.

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Besides utilizing as a spice, it is also used as the main ingredient in çiğköfte that is a

48

traditional Turkish food.

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The flavor is a key factor in consumer preferences as a sensorial property. Fruit and vegetable

50

flavors derived from the association of taste and aroma (Kader, 2008; Klee, 2010). The taste

2

51

of pepper fruits is primarily represented by sugars and organic acids, whereas the aroma

52

characterized by a large number of VC. The composition and amount of flavor components in

53

pepper spices vary depending on pre- and post-harvest conditions. Production processes of

54

spices, such as drying conditions (Martin et al., 2017), applications and techniques (Korkmaz

55

et al., 2017) have crucial impacts on the flavor of final products.

56

It is well known that storage plays an important role in the overall acceptability and shelf life

57

of foodstuffs as well as the production. Pepper spices generally not consumed immediately

58

after drying and are stored in packages for months. There are several studies investigating

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changes in the quality properties of dry pepper derivatives during storage. However, most of

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these have been carried out on pungency and color (Topuz & Ozdemir, 2007) and other

61

features (Wang et al., 2018). Nevertheless, few studies have been conducted about changes in

62

flavor compounds of red pepper powder (Yu et al., 2018), dry powder herbs (Chaliha, Cusack,

63

Currie, Sultanbawa & Smyth, 2013) and other spices (Liu, et al., 2013) during storage. There

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also are some studies that investigate flavor components of various pepper spices depending

65

on different origins (Zimmermann & Schieberle, 2010), drying methods (Luning, Ebbenhorst-

66

Seller & Rijk, 1995; Martin et al., 2017) and flavored olive oil with dried pepper (Caporaso,

67

Paduano, Nicoletti & Sacchi, 2013). Although storage is a critical process on alteration in the

68

flavor of spices, the study on changes in taste and aroma compounds of dried spices pepper

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manufactured by different ways is limited. Therefore, the present work was aimed to evaluate

70

the changes in VC, organic acids and sugars of sun dried red pepper flakes and isot peppers

71

(Turkish traditional spices) stored at the room conditions for 12 months.

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2. Materials and Methods

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2.1. Production of samples

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Full ripe fresh fruits of ‘Urfa’ type pepper (Capsicum annuum L. cv. Inan3363) were used in

75

the processing. Firstly, seeds and stems of peppers were removed. Then, they were

3

76

longitudinally slices into 2-3 pieces after wasing with water. These slices were divided into

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three groups for different productinos methods. The details of the different production

78

methods are shown in Fig. S1. Each production was performed in triplicate.

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2.1.1. Red pepper flakes (RPF)

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The slices in the first group were spread out for drying under sun onto a cleaned concrete

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floor. The drying process was continued for 96 h until the moisture content reached below

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15% (w/w) in accordance with the commercial red pepper flakes of Turkey. The air

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temperatures were measured three times (00.00 a.m.; 06.00 a.m.; 12.30 p.m.) in a day during

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drying process. The average temperature of the weather in the day and night were 33±1, 21±1

85

o

86

2.1.2. Industrial isot (INI)

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The second group slices were dried for 96 h under the sun. Then, slices were ground to size 1-

88

3 mm and tempered to 25% moisture content. After that, the flakes were heated to 85 oC by

89

friction during transferring into a wooden insulated cabinet with a pilot-scale helical conveyor

90

(specifically designed). These heated flakes were kept in the cabinet at 85 oC for 36 h.

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Thereafter, the flakes were taken from the cabinet and were spread for ~2 h for less than 15%

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moisture content.

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2.1.3. Traditional isot (TRI)

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The third group of slices were dried for 48 h under the sun until the moisture content about

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30%. Then, 3000 mL brine (4 g/100 g) was sprinkled onto slices for sweating process called

96

terletme. During this process, slices were placed into polyethylene bags which thinly laid on

97

the concrete floor under the sunlight. The average temperatures inside the bag in day and

98

night were determined 50±1, 23±1 oC, respectively, during terletme processing. The bags

99

were daily turned out and also the slices were removed from the bags and covered by a cotton

C, respectively. After drying, slices were ground to size 2-3 mm by a mill in flakes.

4

100

cloth during nights. After six days, the slices were dried under the sun again for 24 h to below

101

15% moisture rate. Finally, they were ground to 1-3 mm size by a mill.

102

2.2. Storage and sampling

103

The pepper spices were stored in two-ply polyethylene (low-density polyethylene, LDPE)

104

bags. The bags were put in a carton box to prevent light and were stored at an ambient

105

temperature between 20 oC and 25 oC, and relative humidity of 45%-60 %. The oxygen

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transmission rate and water vapor permeability of LPPE film (thickness=40 µm) at 22 oC and

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55% of relative humidity are 5800-6200 cm3/m2 day atm and 9-10 g/m2 day, respectively. For

108

each sampling, 50 g spices were taken for analysis 3 months intervals (0, 3, 6, 9 and 12)

109

during a one-year storage period. Sampling was performed in triplicate per each three spice.

110

2.3. Moisture content and water activity analyses

111

The moisture content of samples was determined according to the AOAC method (1990).

112

Water activity (aw) was measured at 25 oC using a water activity meter (LabTouc-aw,

113

Novasina, Lachen, Switzerland).

114

2.4. Sugars and organic acids analyses

115

The extractions of sugars and organic acids were performed as described by Gallardo-

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Guerrero,

117

Approximately 1 g of the samples was homogenized in 50 mL deionized water using a T25

118

basic Ultra Turrax (IKA, Staufen, Germany). 1 mL sorbitol (0.05 g100 mL) (Sigma-Aldrich

119

Co. USA) was added as an internal standard at the beginning of the extraction. After that, the

120

mixture was held in a water bath during 1 hour at 80 oC. This extract was centrifuged at 13000

121

g 10 min at 4 oC. 1 mL of supernatant was filtrated through a 0.45 µm disc filter and

122

transferred into a vial and 20 µL was used for the analysis.

123

The analyses of sugars and organic acid were carried out by an HPLC (Shimadzu LC-20AD)

124

according to Hayaloglu and Demir (2015). For sugars (sucrose, glucose, fructose and sorbitol)

Perez-Galvez, Aranda, Minguez-Mosquera and Hornero-Mendez

5

(2010).

125

analysis, separation was performed by a Rezex RCM Ca+2 sugar alcohol and monosaccharide

126

column (300 x 7.8 mm, Phenomenex Co, Torrance, Calif., U.S.A) held at 80 oC. The HPLC

127

system consisted of a pump equipped with an auto sampler, a refractive index detector, a SIL-

128

20A HT, CTO-20A column heater and a DGU-20A5 degasser. The sugars were eluted

129

isocratically with an ultrapure water (Milli-Q water, Millipore, Bedford, Massachusetts, USA)

130

at flow rate of 0.6 mL/min during 35 min. Quantification of sugars was achieved by external

131

standard method and results were expressed in gkg-1 dry weight basis. Organic acids were

132

analyzed using a Rezex ROA organic acid column (300 x7.8 mm, Phenomenex Co) at 50 oC

133

with a diode array detector model SPD-M20A set at 210 nm. The mobile phase was 0.005 N

134

H2SO4 with an isocratic flow of 0.5 mL/min during 35 min. Quantification of organic acids

135

(citric, malic and succinic) was performed with authentic standards. The results were

136

expressed as mg g-1 dry weight.

137

2.5. Ascorbic acid analysis (Vitamin C)

138

Vitamin C content in samples was determined as described by Daood, Palotas, Palotas,

139

Somogyi, Pek and Helyes (2014) method with slight modification. A 5 g of sample was

140

homogenized using a T25 basic Ultra Turrax (IKA co.) in 30 mL of 3% meta phosphoric acid

141

solution. The homogenate was sonicated with an ultrasonic bath (Sonorex RK514H, Bandelin,

142

Berlin, Germany) at room temperature for 30 min. Then, the mixture was filtrated by a 0.45

143

µm disc filter and transferred into a vial. A 20 µL of the filtrate was used for injection. The

144

used HPLC was equipped a Luna C18 column (250 x 4.60 mm, 5 µm; Phenomenex Co.) at 31

145

o

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separation of vitamin C was carried out by a gradient elution. The mobile phase was consisted

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of acetonitrile:0.01 M KH2PO4 which was 1:99 at starting, 40:60 at the changing and 1:99 at

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the returning. The flow rate was 0.75 mL/min during the elution. Peak was identified using

149

standard of L-ascorbic acid (Sigma-Aldrich Co. USA). The quantification was performed with

C and a SPD-10AV UV–Vis detector (Shimadzu, Kyoto, Japan) set at 244 nm. The

6

150

a calibration curve obtained from this standard. The results were expressed as mg g-1 dry

151

weight.

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2.6. Volatiles compounds (VC) analysis

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VC

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Divinylbenzene/Carboxen/Polydimethylsiloxane (50/30 μm coating thickness; 2 cm length;

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Supelco, Bellefonte, PA, USA) fiber. A 1 g of the sample was immediately transferred into a

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15 mL SPME vial (Supelco, Bellefonte, PA, USA), and 5 μL of a solution containing each 5

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mg kg-1 of 2-methyl pentanoic acid (1) and 2-methyl-3-heptanone (2) (Sigma-Aldrich Co.

158

USA) in methanol was added as internal standards (IS). The vial was placed on a heater (PC-

159

420D, Corning, NY, USA) at 40 oC for 30 min. Then, the fiber was exposed to head space at

160

40 oC for 30 min. Extraction was done in triplicate.

161

The VC in the samples were determined manually using the SPME fiber in a GC-MS

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(Shimadzu GC-2010 gas chromatography and QP-2010 mass spectrometry system; Shimadzu

163

Corp., Kyoto, Japan) system. Separation was achieved with DB-Wax column (60 m x 0.25

164

mm x 0.25 mm; J&W Scientific, Folsom, CA, USA) and run in splitless mode.

165

Chromatographic conditions were same as described by Korkmaz et al. (2017). Flow rate of

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He used as carrier gas was 1.0 mL/min. The heating gradient program was 40 °C for 2 min,

167

followed by increasing as a range of 3 °C per min to 80 °C kept for 1 min. Thereafter, the

168

temperature was gradually raised to 240 °C with 5 °C per min and held on this stage for 6

169

min.

170

Compounds were identified by comparing their mass spectra with those the Wiley 8 and

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NIST05 mass spectral libraries or literature data and many identifications were confirmed by

172

their retention indices (RIs). The calculation of RIs, n-alkane (C10-C26) series was used under

173

the same chromatographic conditions. Quantitative results were calculated from the peak

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areas of GC/MS with three extractions for each sample with the use of internal standard

were

extracted

by

solid

phase

microextraction

7

(SPME)

technique

with

175

method, as µg kg-1 dry weight of the sample. IS1 and IS2 were used for volatile acids and all

176

other VC, respectively.

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2.7. Statistical analysis

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Significant differences of each mean values were tested by one-way analysis of variance

179

(ANOVA) and Duncan’s multirange (p<0.05). Additionally, principal component analysis

180

(PCA) was performed on the content of VC obtained from GC-MS to explain the changes in

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the VC profile in samples during storage. All the statistical analyses were performed by using

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SPSS (version 16.0, Chicago, IL, U.S.A.) software package.

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3. Results and Discussion

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3.1. Changes in moisture content and water activity of pepper spices

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The changes in moisture content and aw of pepper spices during storage process are shown in

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Fig. 1. Although there were no differences between the initial moisture content of samples,

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the aw values were significantly different. The lowest aw values were obtained from TRI along

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the storage periods. This result is probably caused by the addition of salt during its

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production. The moisture contents of three spices did not change significantly during 12

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months of storage (Fig. 1a). The aw values of RPF and TRI exhibited an upward tendency and

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the aw of long term stored of RPF and TRI raised up to 0. 403±0.009, 0.336±0.003,

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respectively (Fig. 1b). However, aw of INI increased until the sixth months and then decreased

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to 0.451±0.002 at the end of storage. Ordonez-Santoz, Pastur-Garcia, Roero-Rodriguez and

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Vazquez-Oderiz (2014) found similar changes in aw for eight months stored paprika.

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3.2. Changes in sugars during storage

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The changes in sugars of samples during storage are depicted in Fig. 2. Initially, the total

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sugars contents of RPF, TRI and INI were 587.84±2.39, 404.21±2.64 and 279.75±3.52 mg g-1

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dw, respectively. These results indicates that the concentration of sugars in Capsicum spices

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clearly influenced by production process, as found by Gallardo-Guerrero et al. (2010) and

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Sharma, Joshi and Kaushal (2015). The lower sugar level in pepper samples may be attributed

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to the higher heat treatments during production. Drying treatments or thermal applications can

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cause non-enzymatic reactions which reduced the amount of sugars (Gogus & Eren, 1998).

203

Glucose contents of RPF and INI samples showed a gradually decrease during storage, and

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finally reduced 56 and 46% for RPF and INI, respectively. The level of glucose in TRI did not

205

change significantly for the first 9 months (P>0.05), but decreased from 109.9±02.8 to

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86.7±1.2 mg g-1 dw in the last 3 months (Fig. 2a). The slow reduction in glucose during

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storage may be due to the lower aw. Water activity is a major factor affecting the stability of

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dried peppers during storage (Rhim & Hong, 2011). On the other hand, the changes in the

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content of fructose in both isot samples during storage were not significant, while it was

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dropping slightly in RPF between 9 and 12 months (Fig. 2b). The sucrose concentrations (data

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not shown) were negligible in all samples. The decreases in sugars of pepper spices during

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storage are also related to the non-enzymatic browning reactions (Bignardi, Cavazza, Rinaldi

213

& Corradini, 2016). In fact, there was a significant correlation between glucose contents and

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browning index (data not show) of samples (Pearson’s coefficient=-0.794, P<0.01). Also,

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some of the decrease in sugars, especially in TRI, may be due to microbial activity. Rico,

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Kim, Ahn, Kim, Furuta and Kwon (2010) showed that different storage conditions (4 oC and

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20 oC for 6 months) can reduce the total amount of reducing sugars. Another study on red

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pepper powder (Kwon, Byun & Cho, 1984) reported a slight decrease in the level of reducing

219

sugars in irradiated and unirradiated samples for 3 months storage.

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3.3. Changes in organic acids during storage

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The composition of organic acids of fruits is very important on sourness taste. It was seen that

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the amount of organic acid in pepper spices varied based on the methods of production. The

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changes in determined organic acids (citric, ascorbic, malic, and succinic acid) in peppers

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during storage are illustrated in Fig. 3. Citric acid was the dominant organic acid in fresh

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pepper (data not show), while the major acid in its spice form was malic acid, with 5.97±0.01,

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16.51±0.02 and 11.48±0.03 mg g-1 dw for RPF, TRI and INI, respectively. Similarly, Lunnig

227

et al. (1995) also found an increase in malic acid after hot air drying of fresh red peppers.

228

Ascorbic acid (vitamin C) disappeared after the production for both of the isot peppers,

229

whereas it was 2.72±0.03 mg g-1 dw in RPF. However, this amount has not been detected for

230

9 months of stored samples (Fig. 3a). The losses in ascorbic acid can be attributed to effects of

231

production and storage conditions such as temperature, time and relative humidity which can

232

cause its oxidation (Wang et al., 2018).

233

Citric acid did not change significantly for TRI during storage, but increased slightly between

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6-9 months and 9-12 months of storage for RPF and INI, respectively (Fig. 3b). The content

235

of malic acid in three pepper spices increased during storage. In particular, the level of this

236

organic acid in RPF raised sharply (4-fold) after storage (Fig. 3c). Therefore, malic acid was

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found as 63.07%, 66.83% and 74.37% of the total amount of organic acid in TRI, INI and

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RPF, respectively at the end of storage. These increases could be explained by the conversion

239

of glucose to malic acid via microbial actions (Chi, Wang, Wang, Khan & Chi, 2016). The

240

higher increases of malic acid in RPF during storage may be attributed to higher concentration

241

of glucose as substrate in the this spice (Dait et al., 2018). It was found a significant

242

correlation between amounts of malic acid and glucose (Pearson’s coefficient=-0.479,

243

P<0.01). Succinic acid in samples showed a little change during storage (Fig. 3d).

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3.4. Changes in volatile compounds (VC)

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The VC identified and changes in their quantity in samples during storage are listed in Table 1

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according to chemical groups. A total of 136 compounds of three pepper spices were

247

identified by SPME. In general, most of the compounds in samples decreased or disappeared

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after storage. This is probably because of the degradation or volatilization through the

249

packaging material, through the VC migration due to permeability (Chaliha et al., 2013).

10

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Moreover, VC scalping by packaging material also may have resulted in some degree of the

251

losses in VC (Sajilata, Savitha, Singhal & Kanetkar, 2007).

252

It can be seen that the majority of the disappearances occurred in the last 3 months for all

253

samples, while the decreases were observed at the different stages of storage, depended on the

254

sample type. The drastically changes in VC were found for TRI in the first 3 months of

255

storage, so that the total concentration of compounds in this sample reduced suddenly from

256

113.16±2.24 to 20.64±1.48 mg kg-1 dw in this stage. In contrast, some new compounds

257

formed in RPF during the first 3 months, also some of the initial compounds in this sample

258

increased during this period. This could be due to the enzymes that carry on activity after the

259

production of RPF, which has natural conditions, particularly the mild temperature, compared

260

to the case in both isot samples (Wang et al., 2018).

261

The results found herein were similar to previous studies on some other herbs or fruits. For

262

example, Chaliha et al. (2013) compared the changes of major VC in dried powders of three

263

commercial herbs (lemon myrtle, anise myrtle, and Tasmanian pepper leaf) stored in different

264

packages and reported that the packaging material clearly affected the losses rate of major

265

VC. They have found that the major VC in dried powders of lemon myrtle, anise myrtle and

266

Tasmanian pepper leaves packaged with polyethylene bags decreased significantly (of up to

267

87%) after 6 months of storage at ambient temperature. Liu et al. (2013) observed significant

268

decreases in main VC contents in ground pepper (Piper nigrum L.) after 6 months of storage

269

at 4 oC. However, Yu et al. (2018) reported that fewer changes in VC of irradiated and non-

270

irradiated red pepper powders stored in aluminum foil bags for 8 months. The changes in the

271

main chemical groups during storage are illustrated in Fig. 4 in terms of total concentrations

272

and numbers of compounds, and are discussed below.

273

3.4.1 Changes in terpenoids

11

274

Terpenoids are responsible for the fruity and herbal odor (The Good Scent, 2019). The

275

noticeable changes in terpenoids were observed in TRI within the first 3 months of storage. The

276

most of initial terpenoids in TRI such as β-myrecene, p-cymene and α-thujene disappeared in

277

this stage, while some others decreased, and consequently the total terpenoids content in this

278

spice dramatically decreased (by 98%) after the first period of storage (Fig. 4a1). Despite the

279

decrease in the total content of terpenes in INI during storage, these changes were not

280

significant. Unlike isot samples, in RPF, some new terpenes such as dihydrolinalool,

281

hydroxycitronellol and β-myrecene were generated in the first 3 months of storage, while α-

282

limonene (lemon, orange-like) increased. Thus the total terpenes in RPF increased after the 3

283

months of storage. α-Limonene was also the most abundant terpenoid in 3 samples during

284

storage. This compound has also been reported previously as one of the most abundant

285

monoterpenes in dried Capsicum cultivars (van Ruth, Roozen, Cozijnsen & Posthumus, 1995a;

286

Caporaso et al., 2013). Many initial terpenoids in samples disappeared after storage (Fig. 4a2).

287

3.4.2. Changes in aldehydes

288

Aldehydes were the most diverse class in 3 samples during storage. The most of aldehydes in

289

TRI reduced in the first 3 months of storage, and thus the total level of this group reduced from

290

11.52 to 4.26 mg kg-1 dw in this period, and thereafter the changes in this level were not

291

significant. The total aldehydes content in INI and RPF did not change significantly during

292

storage (Fig. 4 b1). The aldehydes losses in TRI and RPF mostly occurred in the last 3 months

293

of storage (Fig. 4b2). Among fatty acids derived aldehydes in samples, (E)-2-hexenal, heptanal

294

(Z)-2-heptenal, octanal, (E)-2-nonenal and nonanal disappeared after 6 or 9 months of storage,

295

while hexanal (fresh-grassy) remained in samples during storage. This is possible because of

296

the continuation of hexanal production during storage (Mira, Gonzalez-Benito, Hill & Walters,

297

2010). β-cyclocitral, as an oxidative product of β-carotene, remained also in samples until the

298

final stage of storage. This can be explained by a balance between its losses and generation

12

299

during storage (Yahya, Linfort & Cook, 2014). 2-methylpropanal, 2- and 3-methylbutanal (hint

300

of chocolate) increased in pepper samples studied in the last 3 months of storage in contrast

301

with other aldehydes. These compounds could be produced by Strecker degradation from

302

valine, leucine and isoleucine, respectively (van Ruth, Roozen & Cozijsen, 1995b; Mateo,

303

Aguirrezabal, Dominguez & Zumalacarregui, 1997). The increases or accumulations of these

304

aldehydes in the last period of storage could be a result of a prolonged storage time and the

305

relatively higher storage temperature ranges as between August and October (Cremer &

306

Eichner, 2000; Choi, Suh, Kozukue, Kozukue, Levin & Friedman, 2006).

307

3.4.3. Changes in alcohols

308

The most of alcohols in TRI such as as etanol, 3-methylbutanol (fermented-like), (E)-2-octen-

309

1-ol, (Z)-2-penten-1-ol and 2-ethyl-1-hexanol decreased rapidly or disappeared completely

310

during the first stage of storage. Hence the total concentration of alcohols in TRI decreased

311

from 5.71 to 0.56 mg kg-1 dw in this duration. Conversely, of these alcohols, ethanol, 3-

312

methylbutanol and 1-penten-3-ol (probably formed from fatty acids) were newly formed in

313

RPF at this stage and therefore the total alcohol content in this sample increased initially (Fig.

314

4c1). However, most of the alcohols in this sample were not detected till the end of storage as

315

well as in INI (Fig. 4c2). 1-pentanol was not detected initially all samples, but appeared after

316

3 months of storage, and then disappeared again in INI and RPF in the last 3 months of

317

storage. Aromatic alcohols phenylmethanol (floral) and 2-phenylethanol (rose) initially

318

detected in all samples and disappeared during the last stage of storage. These alcohols are

319

thought to derived from probably degradation of phenylalanine (Bellincontro, Santis, Botondi,

320

Villa& Mencarelli, 2004).

321

3.4.4. Changes in ketones

322

All ketones in TRI decreased in the first 3 months of storage. Therefore, the total ketones content in

323

this sample clearly decreased during this period, thereafter insignificant changes were determined

13

324

until the end of storage. Total ketones in RPF exhibited an increasing trend between 3 and 9 storage

325

months, whereas it did not change significantly for INI during storage (Fig. 4d1). 3-Hydroxy-2-

326

butanone (acetoin) (creamy) had the highest content among ketones in all samples during storage.

327

Similarly, Aragon et al. (2005) also reported that 3-hydroxy-2-butanone was one of the most

328

abundant ketones in dried red pepper. Some ketones as the Maillard reactions products in INI were

329

found more than TRI and RPF. For instance, cyclotene (sweet caramel) was found only in INI

330

during storage. On the other hand, some degradation products of carotenoids such as 6-methyl-3,5-

331

heptadien-2-one and ketoisophorone (woody) increased till 9 months of storage for RPF, however

332

the latter was not detected in INI. The changes in the composition of ketones in RPF were more than

333

TRI an INI during storage (Fig. 4d2). Many ketones identified in samples have been reported by

334

previous studies on peppers (van Ruth et al., 1995a; Zimmermann & Schieberle, 2000; Martin et al.,

335

2017).

336

3.4.5. Changes in esters

337

Esters usually have pleasant odors and are responsible for the fruity aroma. The total content

338

and number of compounds of esters in TRI dramatically decreased during the first 3 months

339

of storage, while increased in RPF (Fig. 4e1). Total concentration of esters in RPF were

340

higher than other samples during the storage. Changes in the total ester level in INI during

341

storage were not significant, and the total numbers of esters in this sample were lower than

342

two others (Fig. 4e2). Methyl esters of carboxylic acids were the common ester compounds in

343

pepper spices during storage. Among the most abundant esters in the prior TRI, n-butyl

344

isobutyrate and isobutyl butyrate was not detected at the first stage of storage, while methyl

345

caproate decreased markedly. Methyl acetate (ethereal, fruity) as the most important ester in

346

samples at all stages of storage (except for the initial TRI), was found as 74.9%, 667% and

347

93.8% of total esters in the final TRI, INI and RPF, respectively. Methyl cinnamate (balsamic,

348

spicy) was generated in 3 samples at the last stage of storage.

14

349

3.4.6. Changes in acids

350

The total concentrations of volatile acids in samples were higher than all other groups during

351

storage. It increased for all samples after storage (Fig. 4f1). It was found that only acetic acid

352

(vinegar-like) represented substantially the total amount of VC, constituting 12.6-52.2%, 30.3-

353

61.7% and 44.4-68.3% of total VC content in TRI, INI and RPF during storage, respectively.

354

This acid decreased in TRI up to 6 months of storage, but then increased until the end of

355

storage, whereas increased in INI during the whole period of storage. Its concentration in RPF

356

increased up to 3 months, and increased again during the latter 9 months of storage. Mateo et al.

357

(1997) and Martin et al. (2017) have previously described acetic acid as the main VC in red

358

pepper spices produced by different drying methods. Acetic acid may be produced by

359

catabolism of carbohydrates (Mateo et al., 1997) and by microbial activities during drying

360

(Caporaso et al., 2013). Number of acids during storage were lower than other groups (Fig.

361

4f2).

362

3.4.7. Changes in furans

363

The total furans content in TRI decreased distinctly during the first 3 months of storage,

364

thereafter was stable up to the end of storage. The total furans content in INI during storage

365

decreased and was higher than in other samples (Fig. 4g1). Unlike others this difference is

366

probably related to the ‘kepertme’ process used in INI producing as the application of higher

367

temperature range. The changes in this content in RPF were not significant during storage. The

368

distribution of furans in TRI and INI during storage was relatively similar in RPF. Furthermore,

369

the numbers of furans in isot samples were more than in RPF during storage. The numbers of

370

furans in INI decreased linearly during storage, whereas these numbers in TRI and RPF have

371

not changed after the first 3 months of storage (Fig. 4g2). 2-Methyldihydro-3(2H)furanone (nut-

372

like) in both isot samples primarily decreased and disappeared during the first and second 3

373

months of storage, respectively, but then appeared and increased again. Increasing of furans and

15

374

the others during the storage was due to non-enzymatic browning reactions, which are

375

caramelization of sugars or Maillard reactions between sugars and amino acids (Kebede et al.,

376

2013).

377

Besides the changes in groups mentioned above, other groups (including alkanes, aromatic

378

hydrocarbons, pyrazines, sulfur compounds and miscellaneous) in samples also showed notable

379

changes during storage (Table 1).

380

3.5. Principal component analysis (PCA)

381

The results of PCA of VC in TRI, INI and RPF during storage are presented in Fig. 5. The

382

first two components (PC1 and PC2) explained 67.17% of the total variance. PC1 and PC2

383

explained 56.05% and 12.12% of the total variance, respectively. The TRI sample before

384

storage (TR0) that clearly separated from other samples along PC1 in score plot, changed

385

remarkably during 3 months storage. The TRI samples from this stage (TRI3, TRI6, TRI9 and

386

TRI12) clustered with RPFs in the same region (Fig. 5a). The separations or changes in this

387

isot pepper are driven by many compounds listed in Table 1, which are shown in loading plot

388

(Figure 5b). On the other hand, INIs separated from RPFs by PC2, and also clustered

389

separately as the initial INI (INI0) and others (INI3, INI6, INI9 and INI12). PCA confirmed

390

the major changes in VC profile of both isot peppers, especially in TRI, during the first 3

391

months storage. The evidently least changes were found in VC of these samples on

392

subsequent storage months.

393

4. Conclusion

394

Based on this study, it can be concluded that behavior of the changes in sugars, organic acids

395

and VC profile of dried red pepper types during storage significantly affected by the used

396

production methods. The results also indicate that lower temperature treatments or mild

397

drying conditions during production can cause more biochemical alterations in pepper spices

398

through storage. Thus, glucose and fructose displayed decreases in RPF compared to both the

16

399

in isot samples after storage. Malic acid in this sample increased a distinctly. Although the

400

decreases in glucose of samples may be due to non-enzymatic browning reactions, the further

401

decreases in glucose for RPF also likely to be its conversion into malic acid through

402

enzymatic pathways. This possibility supported by Pearson coefficient between the two

403

components. On the other hand, the data showed that VC in pepper spices exhibited different

404

changes during storage. The decreases or disappearances in VC of TRI that were the major

405

changes, occurred in the first 3 months storage. In contrast, some new VC were detected in

406

RPF in this stage. Eventually, many compounds in all samples were not detected within the

407

last 3 months period. Therefore, the differences between VC composition of sample have

408

been less compared to the initial situation. As a conclusion, the flavor constituents of dried red

409

pepper spices can be deteriorated significantly during storage. Hence, further studies are

410

needed on appropriate storage conditions and packaging material for flavor stability of red

411

pepper spices.

412

Acknowledgments

413

This research was supported by The Southeastern Anatolia Project Regional Development

414

Administration, Republic of Turkey Ministry of Development (Project: GAP-ISOT) and

415

Harran University Scientific Research Institutions (HUBAK Project No: 14010). The authors

416

thank Experimental Station of GAP Agricultural Research Institute for providing the pepper

417

used fruits (Capsicum annuum L. cv. Inan3363) for the study.

418

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419

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22

Table(s)

Table 1. Changes in volatile compounds (mg kg-1 dry weight) in red pepper flakes, industrial isot and traditional isot during storage Storage samples (months) Compounds TRI INI RI* 0 3 6 9 12 0 3 6 9 12 Terpenoids 33.37aA 1.37bA 1.10bA 0.51bA 0.04bA 1.16aB 0.94aB 0.86aA 0.43aA 0.25aA 1 α-Thujene 1014 1.61aA nd nd nd nd nd nd nd nd nd 2 δ -3-Carene 1.143 1.11aA nd nd nd nd nd nd nd nd nd 3 β-Myrecene 1.156 3.80aA nd nd nd nd 0.12aB 0.08abA 0.04abA 0.02bA 0.05abA 4 α-Limonene 1196 14.80aA 0.99bA 0.73bA 0.06bA 0.03bA 0.36aB 0.52aA 0.59aA 0.07aA 0.15aA 5 1,8-Cineole 1206 2.40aA nd nd nd nd nd nd nd nd nd 6 cis-Ocimene 1229 nd nd nd nd nd 0.07aA nd nd nd nd 7 α-Terpinene 1244 2.64aA 0.02bA 0.01bA nd nd 0.02aB 0.01abA trbcA nd nd 8 β-Ocimene 1246 1.13aA nd nd nd nd 0.09aB nd nd 0.05abA nd 9 p-Cymene 1269 4.26aA nd trbA nd nd nd nd nd nd nd aA 10 Dihydrolinalool 1422 0.04 nd 0.02abA nd nd 0.02aA 0.02aA 0.01aA nd nd 11 Hydroxycitronellol 1454 nd nd 0.07aA nd nd 0.07aA nd nd nd nd 12 α-Copaene 1500 0.77aA 0.04bA 0.05bA 0.03bA nd 0.07aB nd nd 0.02bA nd 13 Linalool 1534 0.62aA 0.08bAB 0.07bA 0.06bA 0.01b 0.17aB 0.16aA 0.11aA 0.06aA 0.04aA aB aA aA aA 14 β-Elemene 1594 0.08± 0.04 0.04 0.02 nd 0.06aB 0.05aA 0.02abA 0.02abA nd aA bcA bA 15 α-Terpineol 1692 0.61 0.12 nd 0.18 nd 0.08aB 0.05aA nd 0.05aB nd aA 16 α-Muurolene 1715 0.21 nd nd nd nd nd nd nd nd nd 17 (Z)-Geranylacetone 1851 0.07aA 0.01bcA 0.03bcA 0.04bA nd 0.01aB 0.01aA 0.02aA 0.03aA nd 18 (E)-α-Ionone 1858 0.06aA 0.01bA 0.01bA 0.02bA nd nd nd nd nd nd 19 (E)-8-Hidroxylinalool 1917 0.04aA nd nd nd nd nd nd nd nd nd 20 (E)-β-Ionone 1947 0.08aA 0.03abA 0.05abA 0.07abA nd 0.01aA 0.02aA 0.041aA 0.05aA nd 21 5,6-epoxy-β-Ionone 2002 0.02abA 0.01abA 0.03abA 0.04aA nd nd nd 0.02aA 0.03aA nd aA bA bcA cA bcAB bB bB Aldehydes 11.52 4.26 2.99 1.34 3.29 2.57 1.96 1.99bAB 0.73bB 6.22aA 22 Acetaldehyde 706 0.16aA 0.04bA 0.02bA 0.02bA 0.03bA nd 0.01bA 0.021bA 0.01bA 0.05aA 23 Propanal 756 0.08aA 0.04bA 0.01cA trcA trcA nd nd traA nd nd aA cA cA cA bAB bB bA 24 2-Methylpropanal 777 2.93 0.20 0.14 0.22 2.05 0.25 0.18 0.27bA 0.40bA 3.62aA 25 3-Methylbutanal 895 0.17 bB 0.34abA 0.28bA 0.29bA 0.58aB 0.70abA 0.26bA 0.33bA 0.10bA 1.72aA 26 2-Metilbütanal 890 0.15bB 0.14bB 0.12bA 0.15bA 0.39aA 1.01aA 0.57bA 0.08cA 0.08cA 0.36bA 27 Pentanal 962 0.14aA 0.09bA 0.05cA 0.02dA 0.03cdA 0.06aB 0.05abA 0.04abA 0.01bA 0.03abA 28 Hexanal 1071 1.97bA 2.47aA 1.49cA 0.26dA 0.15dA 0.17aC 0.42aB 0.66aB 0.10aA 0.42aA 29 (E)-2-Pentenal 1123 0.37aA 0.04bA 0.02bA nd nd nd nd nd nd nd 30 Heptenal 1180 0.60aA 0.08bA 0.08bA nd nd 0.03abB 0.04abA 0.06aA 0.02abA nd 31 (E)-2-Hexenal 1215 0.46aA 0.07bA 0.04bcA 0.01cA nd 0.02aB 0.02aA 0.02aA nd nd aA bA bA bA 32 Octanal 1285 0.34 0.05 0.05 0.02 nd 0.03abB 0.03abA 0.04aA 0.04aA nd 33 (Z)-2-Heptenal 1324 0.47aA 0.12bA 0.03bA nd nd 0.02aB 0.02aB 0.01aB nd nd

0 0.56bB nd nd nd 0.29bB nd nd nd nd nd nd nd 0.08abB 0.04aB 0.15aA nd nd trbcB nd nd traA nd 1.07aB 0.08aAB 0.01aB 0.13bB nd 0.04bB trbC 0.39aB 0.03aA 0.07aB 0.03aB nd 0.03aB

3 0.94aB nd nd nd 0.70aA nd nd 0.01aA nd nd 0.02aA 0.02aA 0.03abA 0.02abB 0.11bA nd nd trabcA nd nd 0.01aA traA 0.89aC 0.01bA nd 0.17bA 0.16bA 0.08bB nd 0.04bB 0.01bAB 0.07aA 0.03aA 0.04aA 0.01bB

RPF 6 1.11aA nd nd 0.01aA 0.80aA nd nd 5 bA tr nd nd 0.02aA 0.03aA 0.09aA 0.04abA 0.09bA nd nd trabB 0.01aA nd 0.01aA nd 0.97aB 0.01bA nd 0.14bA 0.16bA 0.09bA nd 0.16abC nd 0.04bA 0.01aA 0.04aA nd

9 0.39bA nd nd nd 0.12bcA nd nd nd nd nd 0.01abA 0.03aA 0.07abA 0.04aA 0.02cA nd nd 0.01aA 0.02aA nd 0.03aA 0.02aA 2.04aA 0.02abA nd 0.50aA 040aA 0.15abA nd 0.20abA nd 0.03cA nd 0.053A nd

12 0.05cA nd nd nd 0.03cA nd nd nd nd nd nd nd nd nd 0.02cA nd nd nd nd nd nd nd 1.73aB 0.04abA 0.01aA 0.67aB 0.47aB 0.31aA 0.02aA 0.14abA nd nd nd nd nd

34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 67 68 69 70

Nonanal Decanal (E,E)-2,4-Heptadienal Phenylmethanal (E)-2-Nonenal β-Cyclocitral 2,5-Dimethylbenzaldehyde 2-Phenyl-2-butenal Alcohols Ethanol 1-Penten-3-ol 3-Methylbutanol 1-Pentanol 2-Metilpentanol (Z)-2-Penten-1-ol 1-Hekzanol 2-Ethyl-1-hexanol (E)-2-Octen-1-ol Phenylmethanol 2-Phenylethanol Ketones 2,3-Butanedione 2,3-Pentanedione (E)-3-Penten-2-one 2-Heptanone 3-Hydroxy-2-butanone 1-Hydroxy- 2-propanone 6-Methyl-5-hepten-2-one (E)-3-Octen-2-one 3,5-Octadien-2-one 6-Methyl-3,5-heptadien-2-one Ketoisophorone Cyclotene Esters Methyl acetate Ethyl acetate Methyl propanoate Methyl butyrate Isobutyl isobutyrate Isopropyl valerate

1390 1494 1495 1530 1536 1629 1741 1937 907 1146 1193 1238 1264 1308 1341 1478 1603 1869 1909 957 1046 1119 1177 1285 1294 1334 1406 1518 1594 1697 1821 786 851 876 968 1081 1128

0.45aA nd 0.65aA 1.08aA 0.24aA 1.18aA 0.06aA 0.06aA 5.71aA 2.35aA nd 1.55aA nd 0.05aA 0.24aA nd 0.31aA 0.71aA 0.07aA 0.42aA 6.47aA 0.20aA 0.06aB 0.30aA 0.07aA 3.53aA nd 0.76aA 0.10aA nd 1.07aA 0.40aA nd 17.80aA 0.23bB 0.64aA nd 0.07aA nd nd

0.10bA nd 0.13bA 0.13bA 0.05bA 0.17bA 0.02aAB nd 0.56bA nd 0.18aA nd 0.20aA nd 0.08bA 0.04aA nd 0.02bB 0.01bAB 0.03bA 1.13bA 0.04bB 0.02aB 0.02bA 0.01bA 0.54bA nd 0.15bA 0.07abA 0.14aA 0.03bB 0.10cdA nd 0.40cB 0.13bB nd nd nd 0.04aA 0.03aA

0.14bA nd 0.08bA 0.13bA 0.05bA 0.24bA 0.03aA nd 0.60bA 0.07bA 0.14aA nd 0.16aA 0.01bA 0.08bA 0.04aA 0.04bA nd 0.02bA 0.03bA 1.10bAB 0.04bA 0.04aA 0.01bA trbA 0.41bB 0.01bB 0.13bA 0.10aA 0.15aA 0.06bB 0.14bcA nd 0.37cB 0.13bB nd trbA trbA trcA 0.01aA

0.07bA nd nd 0.11bA 0.05bA 0.05bA 0.07aA nd 0.25bA 0.04bcA 0.06bA nd 0.06bA nd nd 0.02abA 0.02bA nd 0.02bA 0.03bA 1.00bB 0.04bA 0.02aA 0.01b nd 0.35bB nd 0.07bA 0.03bcA 0.06bA 0.17bAB 0.30abA nd 0.43cB 0.21bB nd trbB nd 0.02bcAB nd

nd nd nd 0.03bA nd 0.01bA nd nd 0.18bA 0.02cA 0.03bA nd 0.04bA nd 0.09bB 0.01abA nd nd nd nd 0.84bA 0.07bA 0.02aA trbB nd 0.56bA 0.13aA 0.03bA nd nd 0.03bA nd nd 1.99bAB 1.49aAB nd 0.04aA 0.02bA 0.03abA 0.03aA

0.08aB 0.01abA nd nd 0.06aB 0.09aB 0.03aA 0.01aB 0.25aB 0.07abB nd 0.03aB nd traB 0.05aB 0.02aA nd nd 0.03aB 0.05aB 1.24aB 0.06aA 0.13aA 0.02abA nd 0.42aC 0.37aA 0.07aB nd 0.02aA 0.05aB nd 0.05aA 0.64aB 0.40aB nd nd nd 0.04aA 0.05aA

0.11aA 0.02abA nd nd 0.05aA 0.12aA 0.05aA nd 0.22aB 0.07abA nd trbB 0.05abB nd 0.05aA 0.02aA nd nd 0.01bA nd 1.08aA 0.05aB 0.06abA 0.01bB nd 0.40aA 0.34abA 0.09aA nd 0.03aB 0.05aB nd 0.04aA 0.60aB 0.27aB nd nd nd 0.26aA 0.04aA

0.14aA 0.06aA nd nd 0.04aAB 0.14aA 0.07aA nd 0.37aA 0.09aA nd nd 0.08aB nd 0.09aA 0.02aA 0.03aA nd trabcA 0.03abA 0.97aB 0.05aA 0.02abA 0.01bA nd 0.32aB 0.31abA 0.10aA nd 0.05aB 0.05aB nd 0.02aA 0.47aB 0.37aB nd 0.01aA traA 0.03aA 0.03aA

0.12aA 0.03abA nd nd nd 0.11aA 0.08aA nd 0.19aA 0.01abA nd nd 0.03bcA nd 0.09aA nd 0.03aA nd trbcB 0.02abA 0.65aB 0.03aA 0.01bA 0.01bB nd 0.13aB 0.25bB 0.04aA nd 0.03aA 0.10aB nd 0.04aA 0.49aB 0.23aB nd nd nd 0.02aA 0.02aA

nd nd nd nd nd 0.02aA nd nd 0.16aA nd nd nd nd nd 0.16aA nd nd nd nd nd 0.69aA 0.04aA 0.07abA 0.04aA nd 0.30aA 0.11cA nd nd nd 0.12aA nd nd 0.78aB 0.52aB nd nd nd nd 0.03aA

0.04aB 0.08aA aAB 0.01 traAB aB 0.06 nd 0.03aB 0.04aB aB 0.02 0.02aB aB 0.10 0.10aA nd nd nd nd 0.21cB 0.45abAB nd 0.02bcB nd 0.06aB nd 0.02abA nd 0.06aB nd traA nd 0.11abA aA 0.02 0.02aA nd 0.06aA aB 0.15 0.08bA aB 0.01 nd 0.03abB 0.02abA 1.99abB 1.11bA 0.10aA 0.15aA 0.03aB trcB aA 0.03 trabC nd traA aB 1.70 0.64cA nd nd 0.07aB 0.09aA abB 0.01 0.03aAB nd nd 0.03cB 0.14bA aB 0.02 0.03aAB nd nd 1.22cB 6.21aA cA 1.06 5.45aA nd nd nd 0.05aA nd 0.04aA bA 0.02 0.09aA abA 0.03 0.06aA

0.09aA 0.01aAB 0.01bB 0.03aB 0.02aB 0.15aA nd nd 0.47aA 0.15aA nd 0.03aA 0.04aB traB 0.10abA 0.02aA 0.07aA 0.01cA nd 0.04aA 1.69bA 0.15aA nd nd nd 1.15bcA nd 0.08aA 0.02abB nd 0.25aA 0.03aB nd 3.73bA 3.27bA 0.14aA nd 0.01cA 0.03bA 0.02bA

0.09aA 0.02aA 0.02abA 0.07aAB 0.07aA 0.33aA 0.04aA nd 0.38bA 0.03bA nd 0.02aA 0.05aA trabA 0.15aA 0.03aA 0.06aAA nd nd 0.03abA 2.82aA 0.17aA 0.02bA 0.02ab nd 1.56abA 0.50aA 0.08aA nd nd 0.33aA 0.14aA nd 5.52abA 5.18aA nd 0.04aA 0.02bA nd 0.03bA

nd nd nd 0.03aAB nd 0.06aA nd nd 0.03dB nd 0.01bA 0.01abA nd nd nd nd nd nd nd nd 1.26bA 0.09aA trbcA nd nd 0.90cA 0.21bA 0.03aA nd nd 0.02cA nd nd 3.44bA 3.23bA nd 0.03aA 0.01cAB 0.03bA 0.01bA

71 72 73 74 75 76 77 78 79 80

n-Butyl isobutyrate Isobutyl butyrate n-Amyl acetate Methyl caproate 1-Hexyl acetate n-Butyl n-butyrate Methyl octanoate Methyl salicylate β-Phenethyl acetate Methyl cinnamate Acids 81 Acetic acid 82 Propionic acid 83 Isobutyric acid 84 Butyric acid 85 Isovaleric acid 86 3-Methyl-2-butenoic acid 87 Hexanoic acid 88 Heptanoic acid 89 (E)-2-Hexenoic acid Alkanes 90 Nonane 91 Isododecane 92 2,6-Dimethyloctane 93 Decane 94 3-Methyldecane 95 5-Methyldecane 96 Dodecane 97 2-Methyltridecane Aromatic hydrocarbons 98 Toluene 99 m-Xylene 100 o-Xylene 101 Mesitylene 102 Styrene 103 p-Xylene 104 4-Ethyl-o-xylene 105 Azulene Furans 106 2-Methylfuran

1139 1152 1165 1179 1265 1212 1386 1787 1817 2079 1434 1524 1554 1613 1658 1782 1826 1932 1953 865 941 947 984 1017 1034 1193 1350 1031 1138 1183 1223 1255 1362 1370 1759 832

8.37aA 3.45aA 0.25aA 4.47aA 0.04aA nd nd 0.21aA 0.07aA nd 17.40bA 14.26bA 0.27abA 0.24abA nd 2.41aA nd 0.42bA 0.02aA nd 4.10aA 0.27aA 0.80aA 0.07aA 1.91aA 0.10aA 0.16aA 0.28aA 0.51aA 4.59aA 1.88aA 0.02aB 0.07aA 0.12aA 1.80aA 0.18aA 0.26aA 0.25aA 6.50aA 0.04aA

nd nd nd 0.15bAB trbA nd nd 0.04bA nd nd 10.74cdA 8.99cdB 0.17bA 0.17bA 0.02bcB 0.77cA 0.03abA 0.57bA nd 0.02bA 0.76bA 0.05bA 0.58bA nd 0.03bA nd nd 0.03aA 0.08bA 0.13bB 0.06bA 0.05aB nd nd 0.02bA nd nd nd 0.68bB trbA

trbAB nd nd 0.10bA trbA nd 0.04aA 0.05bA 0.01bAB nd 8.78dB 6.70dB 0.17bA 0.14bA 0.04abA 0.76cB trbA 0.92abA 0.02aA 0.02bA 0.23cAB 0.04bA 0.07cB nd 0.02bA nd nd 0.04aA 0.06bA 0.06cB 0.01bA 0.03aB nd nd 0.01bA nd nd traA 0.83bB trbA

trbB nd nd 0.08bA nd nd 0.02aA 0.08bA 0.01bA nd 13.09cB 10.09cB 0.24abA 0.19bA 0.06aAB 1.09bcA nd 1.36aA 0.03aA 0.03bA 0.15cA 0.02bA 0.02cA nd 0.07bA nd nd 0.02aA 0.03bA 0.05cB nd 0.03aB nd nd nd nd nd 0.02aA 1.30bB nd

0.01bA nd nd 0.08bA nd nd nd nd nd 0.28aA 22.12aB 18.35aB 0.66aB 0.62aA 0.05abB 1.84abA 0.05aA 0.48bA nd 0.07aA 0.11cA 0.06bA 0.02cA nd 0.01bA nd nd 0.02aA nd 0.06cB 0.01bA 0.01aB nd nd nd nd nd nd 0.49bB trbA

nd nd nd nd nd nd nd nd nd nd 0.01aA nd nd nd 0.14aA 0.04bA nd nd nd nd 9.97cB 11.97bcA 8.66bB 9.844bB 0.25bA 0.308bA 0.10bA 0.163bA 0.14aA 0.10aA 0.61bB 1.24bA nd nd 0.15aB 0.23aA nd nd 0.04aA 0.03abA 0.32aB 0.21abB nd 0.03aA aB 0.18 0.08bB aA tr nd 0.05aB 0.04aA nd nd nd nd nd nd 0.08aB 0.05abcA 1.86aB 0.59bA 0.05aB 0.05aB 1.56aA 0.39bA 0.01aB nd nd nd 0.09aB 0.052abA nd nd nd nd 0.15aA 0.10aA 8.10aA 5.53bA traB traA

nd nd nd nd nd nd nd 0.02bB nd nd 13.98bA 11.05bA 0.38bA 0.29abA 0.09aA 1.59abA 0.16aA 0.41aAB nd 0.02abA 0.17bcB 0.04aA 0.03bB nd 0.03aA nd nd nd 0.06abA 0.63bA 0.02aA 0.48bA nd nd 0.02bA nd nd 0.11aA 4.26bcA traA

nd nd nd 0.17aA nd nd 0.06aA nd nd nd 12.81bB 9.92bB 0.53abA 0.30abA 0.11aA 1.62abA 0.16aA 0.18aB nd nd 0.08bcA 0.02abA trbA nd 0.03aA nd nd nd 0.02cA 0.47bA traA 0.31bA nd nd nd nd nd 0.15aA 2.72cdA nd

nd nd nd nd nd nd nd nd nd 0.22aA 31.04aA 25.69aA 1.36aA 0.6aA 0.1aA 2.95aA 0.08aA 0.15aB nd 0.01bB 0.06cA nd 0.04bA nd 0.01aA nd nd nd nd 0.92bA 0.13aA 0.652bA nd nd nd nd nd 0.14aA 2.45dA 0.03aA

nd nd nd 0.08bB nd nd nd 0.01bA 0.01bB nd 9.10cB 8.46cB 0.03aA 0.07bA nd 0.45bB nd 0.08bB nd 0.01aAB 0.12bB nd 0.04bC 0.04aA 0.03aB nd nd nd nd 0.24aC 0.21aB nd nd nd 0.03aB nd nd nd 0.22bB nd

0.05aA 0.04aA nd 0.40aA nd 0.02aA 0.04aA trbcA nd nd 14.06bA 12.47bA 0.13aA 0.17abA 0.05aB 0.92bA nd 0.33aA nd nd 0.17bB 0.02cA 0.07bB traA 0.03aA nd nd 0.02aA 0.02bcA 0.04aB 0.02aA 0.01aB nd nd 0.02aA nd nd nd 0.23bB 0.01aA

0.01bcA trbA nd 0.15abA traA nd 0.01aA 0.04aA 0.02aA nd 9.11cB 8.17cB 0.09aA 0.16abA 0.03bA 0.50bB 0.02bA 0.14abB nd nd 0.39aA 0.04bA 0.20aA traA 0.04aA nd nd 0.03aA 0.07aA 0.04aB 0.01aA traB nd nd 0.02aA nd nd nd 0.23bC nd

0.02bA nd nd 0.18abA nd nd 0.05aA nd nd nd 16.98bA 14.97bA 0.44aA 0.26abA nd 0.87bA 0.18aA 0.27abB nd nd 0.18bA 0.04bA 0.05bA nd 0.03aA nd nd 0.02aA 0.03bA 0.02aB nd 0.02aB nd nd nd nd nd nd 0.80aC nd

nd nd nd nd nd nd nd nd nd 0.13aA 25.62aAB 22.93aAB 0.38aB 0.41aA nd 1.73aA 0.05bA 0.07bB nd 0.01aB 0.13bA 0.06aA 0.02bA nd 0.03aA nd nd 0.02aA nd 0.02aB 0.02aA nd nd nd nd nd nd nd 0.54abB nd

107 2,3,5-Trimethylfuran 1043 0.36aA nd nd nd nd nd nd nd nd nd 108 2-Pentylfuran 1227 1.36aA 0.08bA 0.09bA 0.05bA 0.01bA 0.04aB 0.05aA 0.05aAB 0.02bA nd 109 2-Methyldihydro-3(2H)furanone1261 0.22aB 0.01cB nd 0.03cB 0.15bB 0.60bA 0.343cA nd 0.14cdA 0.99aA aB bB bB bA aA bA cA 110 Furfural 1458 0.86 nd 0.09 0.11 0.04 2.91 1.86 1.04 0.34dA 0.04dA aA bB bA bA bA aA bA bA 111 2-Acetylfuran 1490 0.82 0.12 0.13 0.30 0.09 0.97 0.61 0.55 0.41bA 0.15cA aA bA 112 Furfuryl formate 1492 nd nd nd nd nd 0.17 0.05 nd nd nd 113 Furfuryl acetate 1528 nd nd nd nd nd 0.18aA 0.15aA 0.15aA 0.12aA 0.10aA 114 5-Methylfurfural 1575 0.59aA 0.02aB 0.02aB 0.02aB nd 1.03aA 0.59abA 0.25bcA 0.29bcA nd aA bB bB bB bB 115 2-Furanmethanol 1647 1.23 0.20 0.22 0.27 0.11 1.95aA 1.68abA 2.06aA 1.32abA 1.09cA abA bA abA aA bA 116 5-Methyl-2(3H)-furanone 1685 0.15 0.07 0.13 0.24 0.06 0.04abAB 0.06aA 0.04aA nd nd aA abA abA bA cA 117 5-Methylfurfuryl alcohol 1707 0.91 0.17 0.16 0.27 0.01 0.18aB 0.13aA 0.11aA 0.09aA 0.06aA Pyrazines 1.05aA nd 0.02bB 0.02bB nd 0.07aB 0.04abB nd 0.02bB nd aA aB abA 118 2,6-Dimethylpyrazine 1326 0.59 nd nd nd nd 0.02 tr nd nd nd 119 2,3-Dimethylpyrazine 1344 0.04aA nd nd nd nd nd nd nd nd nd 120 2-Ethyl-6-methylpyrazine 1383 0.13aA nd nd nd nd nd nd nd nd nd 121 2,3,5-Trimethylpyrazine 1403 0.29aA nd 0.02bA 0.02bA nd 0.03aB trbB nd nd nd 122 Tetramethylpyrazine 1472 nd nd Nd nd nd 0.02aB 0.02aB nd 0.02aA nd 123 2-Isobutyl-3-methoxypyrazine 1522 nd nd nd nd nd nd nd nd nd nd Sulfur compounds 0.53aA 0.05bA 0.05bA 0.06bA 0.08bA 0.08aB 0.03bA 0.02bB trbB 0.08aA bA 124 Methanethiol 697 0.02 nd nd nd nd nd nd nd nd 0.03aA aA bB bA bA bA aB aB aB aB 125 Dimethyl sulfide 728 0.41 0.05 0.05 0.06 0.08 0.03 0.02 0.02 tr 0.05Aa aA aB bA 126 Dimethyl disulfide 1065 0.10 nd nd nd nd 0.03 tr nd nd nd 127 Dimethyl trisulfide 1389 nd nd nd nd nd 0.02aA trbA nd nd nd Miscellaneous 3.47aA 0.65bA 0.85bAB 1.40bB 0.64bB 2.30bA 1.33bA 1.86bA 2.32bA 4.21aA 128 1-Methylpyrrole 1134 0.15aA 0.03bA 0.02bA 0.02bA 0.01bA nd nd nd 0.01aA 0.04aA abA abA aA abA bB aB aA aA 129 Unknown 1607 0.32 0.21 0.34 0.26 0.07 0.04 0.05 0.26 0.22A 0.16a aA bA bA bB bB bA bA bA bB 130 γ-Butyrolactone 1639 1.05 0.17 0.23 0.25 0.18 0.39 0.29 0.25 0.37 1.42aA aA bA bA bA bA aB abA 131 Dimethylmaleic anhydride 1738 0.14 tr 0.02 0.04 tr 0.03 0.01 nd nd nd 132 Dihydromaltol 1859 nd nd nd nd nd 0.28aA 0.15abA 0.06bA 0.07bA 0.02bA 133 2-Acetylpyrrole 1968 1.10aA 0.16bA 0.17bB 0.51bB 0.29bB 1.13bA 0.49cA 1.13bA 1.55bA 2.50aA 134 Pantolactone 2026 0.04aA nd nd 0.02aA nd 0.03aA nd nd 0.05aA nd aA bA bA bAB bA aAB abA abA 135 Pyranone 2246 0.42 0.02 0.02 0.03 0.04 0.40 0.17 0.11 0.04bA 0.02bAB aA 136 Isoeugenol 2321 0.26 nd nd nd nd nd nd nd nd nd Total 113.16aA 20.64cA 16.90cB 19.32cB 29.75bB 28.55bB 24.10bA 25.47bA 20.86bB 46.76aA * Calculated retention indices on DB-Wax column. TRI, Traditional Isot; RPF, Red pepper flakes; INI, Industrial Isot; nd, notdetected; tr, trace; Three replicates of each sample were analyzed. a-d Means with different letters in the same row were significantly different between storage times in same sample (P < 0.05). A-D Means with different letters in the same row were significantly different between same storage times in different sample (P < 0.05).

nd 0.04aB nd 0.01aC traB nd nd nd 0.17aB nd traB 0.18aB nd traAB nd 0.05aB 0.10aA 0.03aA 0.05bB traA 0.05bB nd nd 0.3bB 0.07aA 0.06aB 0.22bA nd nd nd nd nd nd 15.10cC

0.04aA 0.02abA nd 0.04aB 0.04aB nd nd nd 0.08aB nd nd 0.11bA traA traA 0.01aA 0.02bA 0.07aA nd 0.24aA nd 0.21aA nd nd 0.72bA 0.05aA 0.20aA 0.14bA nd nd nd nd nd nd 24.83bA

0.01abA 0.02abB nd traC 0.08aA nd nd nd 0.10aB nd nd 0.09bA nd traA nd 0.02abA 0.06aA nd 0.04bAB nd 0.04bAB nd nd 0.62bB 0.01aAB 0.21aA 0.30bA nd nd nd nd nd nd 18.39cAB

nd 0.02abA 0.04abB 0.08aB 0.30aA nd nd nd 0.27aB nd 0.08aA 0.11bA nd nd nd 0.03abA 0.08aA nd 0.05bA nd 0.05bA nd nd 1.40aAB 0.07aA 0.46aA 0.71aA nd nd 0.07bC nd 0.02aB nd 30.62aA

nd trbA 0.18aB 0.04aA 0.06aA nd nd nd 0.22aB nd 0.02aA 0.01cA nd nd nd nd 0.01aA nd 0.05bA nd 0.04bA nd nd 0.73bB 0.04aA 0.09aB 0.38abB nd nd 0.18aB nd nd nd 33.58aB

Figure(s) Click here to download Figure(s): Figures.docx

(b)

(a)

Fig. 1. Changes in moisture (a) content and aw (b) of TRI, RPF and INI during the storage. TRI: Traditional Isot; RPF: Red Pepper Flakes; INI: Industrial Isot. a-c Different lowercase letters were significantly different during storage periods (P < 0.05); A-C Different uppercase letters were significantly different among samples of the similar storage times (P < 0.05).

(a)

(b)

Fig. 2. Changes in glucose (a) and fructose (b) contents in TRI, RPF and INI during the storage. TRI: Traditional Isot; RPF: Red Pepper Flakes; INI: Industrial Isot. a-c Different lowercase letters were significantly different during storage periods (P < 0.05); A-C Different uppercase letters were significantly different among samples of the similar storage times (P < 0.05).

(a)

(b)

(c)

(d)

Fig. 3. Changes in organic acids in TRI, RPF and INI during the storage: (a) ascorbic; (b) citric; (c) malic; (d) succinic. TRI: Traditional Isot; RPF: Red Pepper Flakes; INI: Industrial Isot. a-c Different lowercase letters were significantly different during storage periods (P < 0.05); A-C Different uppercase letters were significantly different among samples of the similar storage times (P < 0.05).

(a1))

(a2)

(b1) )

(b2) )

(c1)

(c2)

(d1)

(d2)

(e1)

(f1)

(g1)

(e2)

(f2)

(g2)

Fig. 4. Changes in total concentration and number of compounds of VC groups in TRI, RPF and INI. TRI: Traditional Isot; RPF: Red Pepper Flakes; INI: Industrial Isot. a-c Different lowercase letters were significantly different during storage periods (P < 0.05); A-C Different uppercase letters were significantly different among samples of the similar storage times (P < 0.05).

(a)

(b)

Fig. 5. Scores plot (s) loadings plot (b) in rotated space of the two first components of PCA for TRI, RPF and INI samples during storage. Abbreviations: i= identified and compounds codes were numbered from 1 to 135 as given in Table 1. TRI: Traditional Isot; RPF: Red Pepper Flakes; INI:Industrial Isot.

Fresh ripe red pepper (~200 kg, C. annum L. cv Inan3363, moisture 90.49%) Washing Removing seeds and stems

Cutting into 2-3 pieces by hand

Sun drying, 55 kg slices (on a concrete floor, ~48 h) (moisture < 30%)

Sun drying, 55 kg slices (on a concrete floor, ~96 h) (till moisture <15%)

4% brine sprinkling (adding 300 mL)

Sun drying, 55 kg slices (on a concrete floor, ~96 h) (till moisture <15%)

Grinding (by a mill, size 1-3 mm

Putting in transparent PE bags Grinding (by a mill, size 1-3 mm

Exposuring sun light (Terletme) Airing break (covered cotton cloth, night time)

6 days

Heating (from 30 to 85 oC by friction force)

Holding (85 oC, ~36 h)

Sun drying (~24 h, till moisture <15%) Grinding (by a mill, size 1-3 mm) Traditional isot, TRI

Tempering (adding water, moisture 25-27%)

Spreading (~2 h, till moisture < 15%) Red pepper flakes, RPF

Industrial isot, INI

Fig. S1. Production scheme of TRI, RPF and INI. TRI: Traditional Isot; RPF: Red pepper flakes; INI: Industrial Isot.

    

Changes in flavor components of pepper spices during storage were evaluated The changes in the flavor components affected by the production methods and storage Glucose decreased in all samples during storage, but fructose reduced only in Red Pepper Flakes (RPF) Malic acid increased during storage, especially in RPF. Volatiles in samples decreased both qualitatively and quantitatively after storage