Eur Food Res Technol (2013) 237:801–809 DOI 10.1007/s00217-013-2053-3
ORIGINAL PAPER
Physical and chemical properties of tomato, green tea, and ginseng-supplemented corn extrudates produced by conventional extrusion and CO2 injection process M. Tugrul Masatcioglu • Erkan Yalcin Mihwan Kim • Gi-Hyung Ryu • Sueda Celik • Hamit Ko¨ksel
•
Received: 2 April 2013 / Revised: 20 June 2013 / Accepted: 22 June 2013 / Published online: 17 July 2013 Ó Springer-Verlag Berlin Heidelberg 2013
Abstract In this study, extrudates were produced from corn flour supplemented with tomato, green tea, and ginseng powder by conventional extrusion and CO2 injection methods. In conventional extrusion process, the die exit temperatures were adjusted to 80, 110, 130 °C and CO2 injection method was carried out at 80 °C. In both extrusion methods, the feed moisture, screw speed, and die diameter were kept constant at 20 %, 250 rpm, and 3 mm, respectively. Corn flour was supplemented with tomato powder at three different levels (4, 8, and 12 %), but ginseng and green tea were added only at 8 % level. The bulk density results generally had an inverse relationship with the expansion index values. Higher tomato powder supplementation levels resulted in higher total phenolic compound levels and antioxidant activities. These increases were around 11-fold as compared to control samples in 12 % tomato powder supplementation level at 130 °C extrusion temperature. The results indicated that antioxidant activity increased with increasing extrusion temperature. This increase might be due to higher amount of Maillard reaction products, with antioxidant activity, formed at higher extrusion temperatures. The color (L*, a*, b*) and hydroxymethylfurfural results proved that the rate
M. T. Masatcioglu S. Celik H. Ko¨ksel (&) Department of Food Engineering, Faculty of Engineering, Hacettepe University, Beytepe, 06800 Ankara, Turkey e-mail:
[email protected] E. Yalcin Department of Food Engineering, Abant ˙Izzet Baysal University, 14280 Go¨lko¨y, Bolu, Turkey M. Kim G.-H. Ryu Department of Food Science and Technology, Kongju National University, Gongju, Chungnam 340-802, South Korea
of Maillard reaction increased at higher extrusion temperatures during the extrusion process. Green tea supplementation resulted in higher total phenolic compounds and antioxidant activity values as compared to tomato and ginseng supplementation under the same extrusion conditions. Keywords Extrusion Total phenolic compounds Antioxidant activity HMF Maillard reaction
Introduction Epidemiological studies have strongly suggested that diets play a crucial role in the prevention of chronic diseases such as heart disease, cancer, diabetes, and Alzheimer’s disease. Antioxidants reduce oxidative damage to biomolecules by modulating the effects of reactive oxidants [1]. Antioxidants may help the body to protect itself against damage caused by reactive oxygen species (ROS), as well as those of nitrogen and chlorine [2]. In recent years, utilization of natural antioxidants to prevent quality deterioration of food products and preserve their nutritional value has been increasing. Tomatoes constitute an important agricultural crop and an integral part of the human diet worldwide [3]. Recent studies have indicated the potential health benefits of a diet rich in tomatoes and tomato products [4–6]. Ginseng and green tea are also widely used as a health supplement and they are well-known nutraceutical foods especially with their antioxidant activity. Extrusion cooking is a high-temperature, short-time (HTST) thermal process that cooks, forms, and dries the product in one integrated operation. Extrusion cooking is one of the most important processes in food development and has some unique features compared to other heat
123
802
processes. It has been observed that functional and nutritional properties of food components might change due to extrusion [7, 8]. Conventional extrusion processes may cause the loss of some of the functional nutrients, such as vitamins, antioxidants, and polyphenolics, because of high temperatures applied. It was reported by Chinnaswamy and Hanna [9] that in conventional extrusion, products expand when liquid water at high temperature and pressure in the melt is converted to vapor on pressure reduction as the extrudate exits the die (flash evaporation). Recently, a new extrusion method by injecting carbon dioxide (CO2) gas into the extruder barrel has been introduced in which CO2 is used as the blowing agent instead of steam [10, 11]. This is also called as cold-extrusion technique and the temperatures are maintained below 100 °C [10]. The most significant advantage of cold extrusion is to prevent the nutrients in foods from the effect of high temperature [12, 13]. On the other hand, the conventional extrusion process combines the application of high temperature and low moisture, which favors the development of Maillard reaction products (MRPs). The Maillard reaction is a complex series of chemical reactions that involve reducing sugars and amino acids, and MRPs are responsible for the brown color and many of the organoleptic properties of foods. MRPs are known as a major source of compounds related to antioxidant activity by heat treatment in various crude foods [14–16]. Besides this positive effect, the Maillard reaction may cause losses in the nutritional value and a variety of MRPs with potential harmful effects, such as hydroxymethylfurfural (HMF) and acrylamide, may be formed during the reaction [17, 18]. The aim of the present study was to produce functional snack foods supplemented with tomato, ginseng, and green tea powder by using conventional extrusion and CO2 injection methods at different extrusion conditions, as well as to study the influence of the supplemented materials and process variables on the total phenolic compounds and antioxidant activities of the obtained extrusion products. Moreover, the influence of heat treatment during extrusion on total antioxidant activity and HMF levels of the extrudates were investigated.
Fig. 1 The screw configurations of twin-screw extruder
123
Eur Food Res Technol (2013) 237:801–809
Materials and methods Materials Commercial corn flour was obtained from Shin Dong Bang Co. (Ansan, Korea), tomato powder from Jung Shin Co. (Pocheon, Korea), ginseng powder from Dongjin Pharmacy Co. Ltd. (Kumsan, Korea), and green tea from Nonghyup Agricultural Association (Ha-dong, Korea). Methods Sample preparation The tomato powder was incorporated into corn flour at three different levels (4, 8, and 12 %; w/w). The ginseng or green tea was blended with corn flour at the 8 % (w/w) level. The tomato powder, ginseng, and green tea were diluted in several steps to achieve reasonable and uniform level of mixing/blending without concentrated pockets of ingredients [19]. The extrudates without tomato powder, ginseng, or green tea were used as control for the samples produced at the same extrusion conditions (die exit temperatures and screw speed). Extrusion process Corn flour was extruded in a co-rotating twin-screw extruder (THK 31, Incheon Machinery Co., Incheon, Korea) with a 25:1 screw length-to-diameter ratio. The screw configuration is shown in Fig. 1. In conventional extrusion, the die exit temperature was adjusted to 80, 110, and 130 °C. Extrusion temperature profile was set depending on the temperature of the die exit. Extrusion temperature profiles were 30/60/80, 30/110/110, and 30/130/130 °C (increasing temperature toward die) when the temperatures of the die exit were adjusted to 80, 110, and 130 °C, respectively. Feed moisture content of 20 % was used while holding the screw speed and die hole diameter constant (250 rpm and 3 mm, respectively). In the CO2 injection process, CO2 gas injection apparatus was mounted on the extruder barrel 180 mm
Eur Food Res Technol (2013) 237:801–809
before the die exit and CO2 gas pressure was 1 MPa (10 bars). In the CO2 injection process, the die exit temperature was 80 °C, extrusion temperature profile was 30/60/80 °C, and feed moisture content was 20 %. When the extrusion system reached the steady state as indicated by constant torque, pressure, and temperature, extrudate samples were collected. The extruder was equipped with a cooling system, and the temperature of the melt was measured at the die exit with a thermocouple. The actual melt temperature was ±3 °C of the set temperature. All collected samples were oven-dried at 50 °C to adjust the moisture content to less than 10 % before grinding in a laboratory mill, followed by passing through a 212-lm sieve. The ground extrudates were stored in airtight plastic containers and held at 4 °C until analysis. The extrudates were produced in two replicates at two different times. Determination of expansion index and bulk density After drying the extrudates overnight, callipers were used to measure the diameter of extruded products. To calculate expansion index (EI), 15 measurements were taken from each replicate sample (30 measurements in total) and the average extrudate diameter was divided by die diameter (3 mm). Bulk density (BD; g/cm3) was determined according to Ryu and Ng [20] and the results are presented as average of three analyses from each replicate extrudate (6 measurements in total). Color measurement RGB values of an image captured by a digital camera were converted into device-independent L*a*b* values by using a computer algorithm. Color measurements of extrudates were determined according to Go¨kmen and Su¨gu¨t [21].
803
consisting of a diode array detector, a quaternary pump, an autosampler, and a temperature-controlled column oven. The analytical separation was performed on an Atlantis dC18 column (4.6 9 250 mm, 5 lm, Waters Corporation, Milford, MA, USA), with the mobile phase (isocratic conditions) of 0.1 % aqueous acetic acid solution: acetonitrile (90:10, v/v) at a flow rate of 1.0 ml/min. The detector wavelength was 285 nm and all separations were performed at 40 °C. The concentration of HMF was calculated by means of a calibration curve built in the range of 0.05–1.0 lg/ml. Each sample was analyzed in duplicate for HMF and the mean of two measurements was reported. Determination of total phenolic content Total phenolic compounds of the extrudates supplemented with tomato powder, ginseng, and green tea were determined according to the modified method of Gutfinger [25] and Singleton et al. [26]. Sample solutions of the extrudates (10 %, w/v) were prepared with dimethyl sulfoxide (DMSO) by extracting at room temperature for 1 h. The mixture was centrifuged and 0.5 mL of supernatant was transferred into a test tube. The concentrated extracts were diluted to tenfold with distilled water and oxidized with the addition of 0.5 mL of Folin–Ciocalteau reagent. After 3 min, the mixture was neutralized with 1 mL of saturated Na2CO3 solution. The contents were vortexed and diluted to 10 mL with distilled water. The reaction was allowed to proceed at room temperature under dark conditions for 1 h. Total phenolic compounds were determined using a spectrophotometer (UV-2101 PC, Shimadzu, Japan) at 725 nm. Gallic acid was used to prepare a standard curve, and the total phenolic content was expressed as mg gallic acid/g dry sample. All analyses were performed in duplicate.
Moisture determination
Determination of antioxidant activity
Moisture contents of raw materials and extrudates were determined according to AACC International Method No. 44-01 [22].
The antioxidant activity was determined as DPPH radical scavenging capacity using the modified method of Yu et al. [27]. Briefly, 0.1 g ground extrudate was extracted with 1 mL distilled water for 1 h at ambient temperature. The mixture was diluted with absolute ethanol (1:3 v/v), vortexed vigorously, and centrifuged at 12,5009g for 15 min. The supernatant was reacted with freshly prepared DPPH solution (the final concentration was 100 lM) at ambient temperature for 10 min in the darkness. At the end of reaction period, the absorbance was measured at 517 nm against a blank of pure ethanol. The antioxidant activity of extrudates was calculated using a calibration curve of Trolox (6-hydroxy-2,5,7,8-tetramethylchroman-2-carboxylic acid) solutions and expressed as mmol Trolox/kg dry sample.
Analysis of HMF The extraction of HMF was performed according to the slightly modified method of Go¨kmen and Senyuva [23]. The extrudates were ground and 1 g was taken for analysis. Formic acid, Carrez Solution I, Carrez Solution II, and absolute ethanol were used for the extraction of the HMF. HMF was analyzed by high-performance liquid chromatography (HPLC), using the method of Go¨kmen et al. [24]. An Agilent 1100 HPLC system (Waldbronn, Germany)
123
804
Eur Food Res Technol (2013) 237:801–809
Statistical analysis
et al. [29] reported that sugar content of tomato was approximately 48 % on dry basis. The presence of components other than starch might have a lubricating effect on the melt. This interferes with the air cell formation and limits the starch gelatinisation required for the expansion of the extrudates; as a result, the products will be less expanded. It was also previously reported that increasing level of tomato derivatives resulted in decrease in EI of extrudates and the authors suggested that this may be attributed to dilution effect of tomato derivatives on starch [28, 30]. At all tomato powder addition levels, the EI values of the samples produced by the CO2 injection process were significantly lower than those produced by conventional extrusion at the same extrusion temperature (Fig. 2). Although the EI values of the extrudates produced with CO2 injection were not larger than the conventional extrudates, these samples had more uniform expansion and their surfaces were very smooth. SEM micrograph results of a previous study by the authors gave supporting evidence that the samples produced by conventional extrusion and CO2 injection process had different expansion properties [13]. In the present study, the conventional extrudates usually consisted of irregular and open air cells, while cross-section of extrudates produced by CO2 injection had uniformly distributed enclosed air cells with thin cell walls. Earlier researchers [12, 31] were also reported lower and more uniform expansion for CO2-injected samples compared to the ones produced by conventional extrusion. As the tomato powder addition level increased, BD values of conventional extrudates generally decreased except the samples produced at 130 °C (Fig. 2). On the other hand, the BD values of CO2-injected extrudates were significantly higher than the BD values of the extrudates
Data were analyzed by using one-way analysis of variance (ANOVA). When significant (p \ 0.05) differences were found, the Duncan test was used to determine the differences among means.
Results and discussion Expansion index (EI) and bulk density (BD) results of corn extrudates supplemented with different levels of tomato powder are shown in Fig. 2. In conventional extrusion, as the die exit temperature (extrusion temperature) increased from 80 to 110 °C, EI values did not change significantly if the samples are compared at the same tomato powder addition levels. On the other hand, significant decreases were observed in expansion index values of both 8 and 12 % (w/w) tomato powder-supplemented samples as the die exit temperature increased from 110 to 130 °C. At 130 °C extrusion temperature, EI values of conventional extrudates supplemented with 8 and 12 % tomato powder were significantly lower than the ones supplemented with 0 and 4 % levels. On the other hand, at 110 °C, EI value of extrudate was significantly lower only at 12 % supplementation level. Huang et al. [3] also reported that too low or too high tomato powder addition level had a negative effect on EI. The consumer acceptability of extrusion products depends mainly on the properties such as expansion ratio, density, and texture. These properties are related to the proportion of starch that affects the number and size of air cells in the extrudates [28]. Incorporation of tomato derivatives into extruded snacks changes the chemical composition of the melt by reducing the starch content and adding sugar and probably other constituents. Davoodi 5.0
0.15
4.0
Bulk density
a
0.12
ab bc c
3.0
C
C
bc
AB
C
A
A
A
AB
d CD
2.0
A
A
A
A 0.09
BC
d de def
bdef
C de ef
ef ef
d D
f
1.0
0.03
0.0
0 0
4
8
12
80°C CO2 injection method
123
0.06
0
4
8 80°C
12
0
4
8
12
0
110°C Conventional extrusion
4
8
130°C
12
Bulk density (g/cm^3)
Expansion index
Expansion index
Fig. 2 Expansion index and bulk density results of corn extrudates supplemented with different levels of tomato powder. Values marked with different letters are significantly different (p \ 0.05). The values 0, 4, 8, and 12 indicate tomato powder addition levels (%) and 80, 110, and 130 °C indicate die exit temperature
Eur Food Res Technol (2013) 237:801–809
805
Table 1 Expansion index and bulk density values of corn extrudates supplemented with 8 % green tea or ginseng powder Die exit temperature (°C)
Supplementation level (%)
Green tea
Ginseng 3
Expansion index
Bulk density (g/cm )
Expansion index
Bulk density (g/cm3)
Conventional extrusion 80
0
3.43b
0.121a
3.43b
0.121a
80
8
2.97c
0.134a
3.20bc
0.122a
110
0
3.78a
0.080bc
3.78a
0.080bc
110
8
2.91c
0.097b
3.23bc
0.096b
130
0
3.79a
0.069c
3.79a
0.069c
130 CO2 injection method
8
2.62d
0.079bc
3.14c
0.090bc
80
0
2.63d
0.128a
2.63d
0.128a
80
8
2.47d
0.125a
2.67d
0.120a
Values followed by the different letter in the same column are significantly different (p \ 0.05). Means are based on 30 measurements for expansion index and 6 measurements for bulk density
8
4.0 Antioxidant Activity
7
A
B
C D
6
3.5 3.0
E
5
2.5 a
4
F d
3
G
I J
g
I
i
J
2.0
b
c
e H
2 1
F
h
J
f
hi
G
1.5
f
1.0
J
Antioxidant activity (mmol Trolox/kg sample)
Total Phenolic Compounds
Total phenolic compounds (mg gallic acid/g sample)
Fig. 3 Total phenolic compounds and antioxidant activity (DPPH scavenging capacity) results of corn extrudates supplemented with different levels of tomato powder. Values marked with different letters are significantly different (p \ 0.05). The values 0, 4, 8, and 12 indicate tomato powder addition levels (%) and 80, 110, and 130 °C indicate die exit temperature
0.5
j 0
k
k 0
4
8
12
80°C CO2 injection method
produced by conventional extrusion at the same die exit temperature and tomato powder addition level. As indicated in Fig. 2, the present study confirmed the results of the earlier studies that also reported an inverse relationship between BD and EI values [32, 33]. The BD values of green tea and ginseng powder-added (8 %, w/w) extrudates produced by conventional extrusion at different die exit temperatures (80, 110, and 130 °C) were higher than respective control samples, but the differences were not significant. In contrast, their expansion values significantly decreased as compared to those of respective control samples except the ginseng-added one produced by conventional extrusion at 80 °C die exit temperature (Table 1). Total phenolic compounds and antioxidant activity (DPPH) results of corn extrudates supplemented with different levels of tomato powder are demonstrated in Fig. 3. As
k
k 0
4
8
12
80°C
0
4
8
12
0
110°C
0.0 4
8
12
130°C
Conventional extrusion
expected, higher tomato powder ratios resulted in higher total phenolic compound levels and antioxidant activity values. It is generally expected that higher extrusion temperature applications might have a deteriorative effect on the nutritional composition of the extruded products. However, the results of the present study indicated that the antioxidant activity increased with increasing extrusion temperature (Fig. 3; Table 4). This increase might be due to higher amount of MRPs formed at higher extrusion temperatures. Therefore, color (L*, a*, b*) and HMF values were determined in order to follow the formation of MRPs. Color values (L*, a*, b*) of corn extrudates supplemented with different levels of tomato powder are presented in Table 2. As shown in Table 2, L* values generally decreased as tomato powder addition level was increased. In conventional extrusion, as the extrusion temperature increased from 80 to 110 °C, L* values
123
806 Table 2 Color values (L*, a*, b*) of corn extrudates supplemented with different levels of tomato powder
The feed moisture content, screw speed, and die hole diameter were kept constant at 20 %, 250 rpm, and 3 mm, respectively. Values followed by the different letter in the same column are significantly different (p \ 0.05). Means are based on duplicate analyses L* brightness, a* redness, b* yellowness
Eur Food Res Technol (2013) 237:801–809
Die exit temperature (°C)
L*
a*
b*
Conventional extrusion 80
0
71.50b
-1.80h
80
4
63.67c
9.08f
80
8
59.54d
14.77bcd
60.82bcd
80
12
52.42e
19.24a
55.08fgh
61.58bc 62.22b
110
0
64.59c
-1.22gh
59.32bcde
110
4
54.67e
11.95def
56.36efgh
110
8
53.39e
16.88ab
57.73cdef
110
12
48.75f
19.23a
51.04ijk
130
0
61.81cd
1.91g
50.03jk
130
4
54.62e
9.90ef
53.46ghij
130
8
51.97e
13.05cde
52.61hij
130
12
46.94f
15.60bc
47.71k
0 4
79.76a 62.38cd
-8.53i 12.68cde
68.72a 62.70b
80
8
54.14e
16.82ab
57.05defg
80
12
51.99e
17.23ab
54.64fghi
CO2 injection method 80 80
significantly decreased as the samples compared at the same tomato powder addition levels, while L* values did not change significantly as the extrusion temperature increased from 110 to 130 °C. The a* values (redness) significantly increased by the addition of tomato powder (p \ 0.05). However, b* values of the extrudates were similar at 0, 4, and 8 % tomato powder addition levels but significantly decreased at 12 % addition level. The color values of the samples produced by the CO2 injection process were generally comparable to the ones produced by conventional extrusion at the same extrusion temperature (80 °C) at all tomato powder addition levels. In this study, HMF values were determined to follow the formation of MRPs. The corn extrudates supplemented with 8 % tomato powder were used to investigate the effects of different extrusion temperatures on HMF formation. The extrudate samples without tomato powder were used as control produced at the corresponding extrusion temperatures. As shown in Table 3, the HMF levels were significantly higher in tomato powder-added extrudates than that of the respective control at each extrusion temperature. Davoodi et al. [29] reported that sugar content of tomato was approximately 48 % on dry basis and Liu et al. [34] stated that around 60 % of the total sugar in tomato is reducing sugar. Therefore, Maillard reaction might have been occured between the reducing sugars and some amino compounds during extrusion cooking process. The HMF values of the samples produced by the CO2 injection process were significantly higher than the ones produced by conventional extrusion at the same extrusion temperature (80 °C). This is probably due to the increased rate of HMF
123
Supplementation level (%)
Table 3 Hydroxymethylfurfural values of corn extrudates supplemented with 8 % of tomato powder and without tomato powder Die exit temperature (°C)
Supplementation level (%)
Hydroxymethylfurfural (lg/g)
Conventional extrusion 80
0
0.72f
80 110
8 0
77.20d 1.61ef
110
8
117.61b
130
0
2.86e
130
8
146.21a
CO2 injection method 80
0
0.75f
80
8
92.00c
The feed moisture content, screw speed, and die hole diameter were kept constant at 20 %, 250 rpm, and 3 mm, respectively. Values followed by the different letter in the same column are significantly different (p \ 0.05). Means are based on duplicate analyses
production at higher acidic conditions resulting from the dissolution of CO2 in the aqueous phase of the feeding material during the CO2 injection process. It is known that CO2 dissolves in water forming carbonic acid and this is expected to increase acidity. It is also known that the rate of HMF production increases at acidic conditions [17]. Degradation of starch during extrusion is mainly due to shear in the barrel as well as dissolution of CO2 in the aqueous phase of the feeding material and thus increased acidity. Higher level of HMF in the samples produced with carbon dioxide injection as compared to the ones produced without carbon dioxide injection is a supporting evidence.
Eur Food Res Technol (2013) 237:801–809
807
Although Maillard reaction is responsible for developing color, taste, and flavor in thermally processed foods, it might have both detrimental and beneficial effects in terms of health and nutrition [15, 18, 35]. In the present study, color and HMF results indicated that the rate of Maillard reaction occurring at higher extrusion temperatures was higher. Higher extrusion temperatures also increased the level of antioxidant activity; however, potential harmful effects of the MRPs such as HMF formed at higher temperatures should also be taken into consideration. Total phenolic compounds and antioxidant activity (DPPH) results of corn extrudates supplemented with 8 % of green tea powder are shown in Table 4. Total phenolic compounds of control samples produced by conventional extrusion did not changed significantly with increasing extrusion temperature. Total phenolic compounds of corn extrudates significantly increased by green tea supplementation (8 %, w/w) in both conventional extrusion and the CO2 injection process. As the extrusion temperature increased, total phenolic compounds significantly increased. These results might be due to higher extractability as a result of the transformation of phenolic compounds from the bound to released form as the extrusion temperature increased. Supporting results are also reported by various other investigators [36–39]. In addition, the antioxidant activity of green tea-supplemented extrudates produced by conventional extrusion increased with increasing extrusion temperature (Table 4). This increase might be caused by two reasons: The first might be the increased extractability of total phenolic compounds, and the second might be the higher amount of MRPs that have antioxidant activity formed during extrusion cooking. Wang et al. [40] reported that reducing sugar
content of green tea was approximately 1.5 %. Hence, Maillard reaction might have been occured between the reducing sugars and some amino compounds during extrusion cooking process. The antioxidant activity of the green tea-supplemented extrudates produced by the CO2 injection process was significantly higher than the ones produced by conventional extrusion at the same extrusion temperature. The dissolution of CO2 in the aqueous phase of the feed during the CO2 injection process is expected to decrease pH, which might increase the extractability of antioxidants from the matrix of extrudates. Yoshida et al. [41] also reported that the amounts of the major catechins (epicatechin, EC; epigallocatechin, EGC; epicatechin gallate, ECg; epigallocatechin gallate, EGCg) extracted from green tea were increased at lower pH conditions. However, the effect of pH on the extractability of antioxidants can be positive or negative, as it depends on the interaction of these compounds with raw material. Therefore, inconsistent results might be encountered in the literature related to the extractability of antioxidants at different pH conditions. Total phenolic compounds and antioxidant activity (DPPH) results of corn extrudates supplemented with 8 % of ginseng powder are illustrated in Table 4. Total phenolic compounds of ginseng-supplemented extrudates produced by both extrusion processes were significantly higher than the respective control samples except the ones produced at 80 °C by conventional extrusion method. The antioxidant activities of the extrudates supplemented with ginseng were significantly higher than respective control samples (p \ 0.05). Moreover, antioxidant activity of corn extrudates supplemented with 8 % of ginseng powder produced by conventional extrusion increased with increasing extrusion temperature (p \ 0.05). The probable reasons of
Table 4 Total phenolic compounds and antioxidant activity (DPPH scavenging capacity) results of corn extrudates supplemented with 8 % of green tea or ginseng powder Die exit temperature (°C)
Supplementation level (%)
Green tea Total phenolic compounds (mg gallic acid/g sample)
Ginseng Antioxidant activity DPPH (mmol Trolox/kg sample)
Total phenolic compounds (mg gallic acid/g sample)
Antioxidant activity DPPH (mmol Trolox/kg sample)
Conventional extrusion 80
0
0.58e
0.17d
0.58d
0.17d
80
8
4.48d
15.89c
0.76d
0.58c
110
0
0.58e
0.18d
0.58d
0.18d
110
8
5.39c
16.57b
1.10c
0.81b
130
0
0.59e
0.23d
0.59d
0.23d
130
8
6.98b
19.48a
1.76b
0.95a
CO2 injection method 80
0
0.55e
0.24d
0.55d
0.24d
80
8
9.73a
19.72a
2.06a
0.71b
The feed moisture content, screw speed, and die hole diameter were kept constant at 20 %, 250 rpm, and 3 mm, respectively. Values followed by the different letter in the same column are significantly different (p \ 0.05). Means are based on duplicate analyses
123
808
Eur Food Res Technol (2013) 237:801–809
this result were discussed previously. Jeon and Lee [42] reported that reducing sugar content of ginseng was approximately 4.5 % on dry basis. Maillard reaction might have been occured between the reducing sugars and some amino compounds during extrusion cooking process as previously mentioned for green tea- and tomato powdersupplemented extrudates. In both extrusion processes, as the corn extrudates supplemented with 8 % tomato powder, green tea and ginseng powder are compared; the green tea-supplemented ones resulted in the highest total phenolic compounds and antioxidant activity values.
Conclusion The effects of the tomato, ginseng, and green tea supplementation on the total phenolic compounds and antioxidant activities of snack foods produced by conventional extrusion and the CO2 injection process were investigated at different extrusion conditions. HMF levels of 8 % tomato powder-supplemented extrudates were also determined to observe the effects of heat treatment on Maillard reaction during extrusion cooking. Higher tomato powder supplementation levels resulted in higher total phenolic compound levels and higher antioxidant activity values. The green tea-supplemented extrudates resulted in the highest total phenolic compounds and antioxidant activity values. A deteriorative effect on the nutritional properties might be expected at higher extrusion temperatures during extrusion; however, in the present study, antioxidant activity increased with increasing extrusion temperature. This might be due to higher amount of MRPs formed. This is supported by lower L* and higher a* values. The formation of MRPs is also supported by increased HMF levels at higher extrusion temperatures. Although extrusion cooking carried out at high extrusion temperatures increased the level of antioxidant activity, potential detrimental effects of the MRPs formed at higher temperatures should also be taken into consideration. Acknowledgments This work was supported by a joint research project between TUBITAK (The Scientific and Technological Research Council of Turkey) and KRF (The Korea Research Foundation) Project No. 106 O 534. The authors thank Professor Vural Go¨kmen for his support in HMF analysis. Conflict of interest
None.
Compliance with Ethics Requirements Physical and chemical properties of tomato, green tea, and ginseng-supplemented corn extrudates produced by conventional extrusion and CO2 injection process. This article does not contain any studies with human or animal subjects.
123
References 1. Adom KK, Liu RH (2002) Antioxidant activity of grains. J Agric Food Chem 50:6182–6187 2. Shahidi F (2000) Antioxidants in food and food antioxidants. Nahrung 44:158–163 3. Huang RC, Peng J, Lu FJ, Lui WB, Lin J (2006) The study of optimum operating conditions of extruded snack food with tomato powder. J Food Process Eng 29:1–21 4. Choi SH, Lee SH, Kim HJ, Lee IS, Kozukue N, Levin CE, Friedman M (2010) Changes in free amino acid, phenolic, chlorophyll, carotenoid, and glycoalkaloid contents in tomatoes during 11 stages of growth and inhibition of cervical and lung human cancer cells by green tomato extracts. J Agric Food Chem 58:7547–7556 5. Tang FY, Shih CJ, Cheng LH, Ho HJ, Chen HJ (2008) Lycopene inhibits growth of human colon cancer cells via suppression of the Akt signaling pathway. Mol Nutr Food Res 52:646–654 6. Erhardt JG, Meisner C, Bode JC, Bode C (2003) Lycopene, b-carotene, and colorectal adenomas. Am J Clin Nutr 78: 1219–1224 7. Harper JM (1989) Food extruders and their applications. In: Mercier C, Linko P, Harper JM (eds) Extrusion cooking. American Association of Cereal Chemists Inc, Minnesota, pp 1–15 8. Moscicki L, van Zuilichem DJ (2011) Extrusion-cooking and related technique. In: Moscicki L (ed) Extrusion-cooking techniques: applications, theory and sustainability. Wiley, Weinheim, pp 1–24 9. Chinnaswamy R, Hanna MA (1988) Relationship between amylose content and extrusion–expansion properties of corn starch. Cereal Chem 65:138–143 10. Ryu GH, Kim BS, Mulvaney SJ (2002) Optimization of extrusion process for dairy ingredient fortification of cornmeal puffed via CO2 gas injection. Food Sci Biotechnol 11:552–556 11. Cho KY, Rizvi SSH (2010) New generation of health snack food by supercritical fluid extrusion. J Food Process Pres 34:192–218 12. Schmid AH, Dolan KD, Ng PKW (2005) Effect of extruding wheat flour at lower temperatures on physical attributes of extrudates and on thiamin loss when using carbon dioxide gas as a puffing agent. Cereal Chem 82:305–313 13. Bilgi Boyaci B, Han JY, Masatcioglu MT, Yalcin E, Celik S, Ryu GH, Koksel H (2012) Effects of cold extrusion process on thiamine and riboflavin contents of fortified corn extrudates. Food Chem 132:2165–2170 14. Lee W, Park SH, Lee S, Chung BC, Song MO, Song KI, Ham J, Kim SN, Kang KS (2012) Increase in antioxidant effect of ginsenoside Re-alanine mixture by Maillard reaction. Food Chem 135:2430–2435 15. Morales FJ, Martin S, Acar OC, Arribas-Lorenzo G, Gokmen V (2009) Antioxidant activity of cookies and its relationship with heat-processing contaminants: a risk/benefit approach. Eur Food Res Technol 228:345–354 16. Yanagimoto K, Ochi H, Lee KG, Shibamoto T (2004) Antioxidative activities of fractions obtained from brewed coffee. J Agri Food Chem 52:592–596 17. Capuano E, Fogliano V (2011) Acrylamide and 5-hydroxymethylfurfural (HMF): a review on metabolism, toxicity, occurrence in food and mitigation strategies. LWT Food Sci Technol 44:793–810 18. Somoza V (2005) Five years of research on health risks and benefits of Maillard reaction products: an update. Mol Nutr Food Res 49:663–672 19. Wesley AS (2005) Small and medium scale milling and fortification background paper. http://www.micronutrient.org/CMFiles/ PubLib/SSF-background-paper-Annie1NRA-3242008-8511.pdf. Accessed Feb 2013
Eur Food Res Technol (2013) 237:801–809 20. Ryu GH, Ng PKW (2001) Effects of selected parameters on expansion and mechanical properties of wheat flour and whole cornmeal extrudates. Starch/Sta¨rke 53:147–154 21. Go¨kmen V, Su¨gu¨t I (2007) A non-contact computer vision based analysis of color in foods. Int J Food Eng 3(5):5 22. AACC International (2000) Approved methods of the American Association of Cereal Chemists, 10th edn. American Association of Cereal Chemists, St. Paul, MN 23. Go¨kmen V, Senyuva HZ (2006) Improved method for the determination of hydroxymethylfurfural in baby foods using liquid chromatography-mass spectrometry. J Agric Food Chem 54:2845–2849 24. Go¨kmen V, Acar OC, Serpen A, Morales FJ (2008) Effect of leavening agents and sugars on the formation of hydroxymethylfurfural in cookies during baking. Eur Food Res Technol 226:1031–1037 25. Gutfinger T (1981) Polyphenols in olive oils. J Am Oil Chem Soc 58:966–968 26. Singleton VL, Orthofer R, Lamuela-Raventos RM (1999) Analysis of total phenols and other oxidation substrates and antioxidants by means of Folin–Ciocalteu reagent. Methods Enzymol 299:152–178 27. Yu L, Haley S, Perret J, Harris M, Wilson J, Qian M (2002) Free radical scavenging properties of wheat extracts. J Agri Food Chem 50:1619–1624 28. Dehghan-Shoar Z, Hardacre AK, Brennan CS (2010) The physico-chemical characteristics of extruded snacks enriched with tomato lycopene. Food Chem 123:1117–1122 29. Davoodi MG, Vijayanand P, Kulkarni SG, Ramana KVR (2007) Effect of different pre-treatments and dehydration methods on quality characteristics and storage stability of tomato powder. LWT Food Sci Technol 40:1832–1840 30. Altan A, McCarthy KL, Maskan M (2008) Evaluation of snack foods from barley–tomato pomace blends by extrusion processing. J Food Eng 84:231–242
809 31. Ferdinand JM, Lai-Fook RA, Ollett AL, Smith AC, Clark SA (1990) Structure formation by carbon dioxide injection in extrusion cooking. J Food Eng 11:209–224 32. Chaiyakul S, Jangchud K, Jangchud A, Wuttijumnong P, Winger R (2009) Effect of extrusion conditions on physical and chemical properties of high protein glutinous rice-based snack. LWT Food Sci Technol 42:781–787 33. Singh N, Singh B, Sandhu KS, Bawa AS, Sekhon KS (1996) Extrusion behaviour of wheat, rice and potato blends. J Food Sci Technol 31:291–294 34. Liu F, Cao X, Wang H, Liao X (2010) Changes of tomato powder qualities during storage. Powder Technol 204:159–166 35. Henle T (2007) Dietary advanced glycation end products—a risk to human health? A call for an interdisciplinary debate. Mol Nutr Food Res 51:1075–1078 36. Peleg H, Naim M, Rouseff RL, Zehavi U (1991) Distribution of bound and free polyphenolic acids in oranges (Citrus sinensis) and grapefruit (Citrus paradise). J Sci Food Agric 57:417–426 37. Dewanto V, Wu X, Liu RH (2002) Processed sweet corn has higher antioxidant activity. J Agri Food Chem 50:4959–4964 38. Jeong SM, Kim SY, Kim DR, Jo SC, Nam KC, Ahn DU, Lee SC (2004) Effect of heat treatment on the antioxidant activity of extracts from citrus peels. J Agri Food Chem 52:3389–3393 39. Choi Y, Lee SM, Chun J, Lee HB, Lee J (2006) Influence of heat treatment on the antioxidant activities and polyphenolic compounds of Shiitake (Lentinus edodes) mushroom. Food Chem 99:381–387 40. Wang HF, Tsai YS, Lin ML, Ou AS (2006) Comparison of bioactive components in GABA tea and green tea produced in Taiwan. Food Chem 96:648–653 41. Yoshida Y, Kiso M, Goto T (1999) Efficiency of the extraction of catechins from green tea. Food Chem 67:429–433 42. Jeon BS, Lee CY (1999) Shelf-life extension of American fresh ginseng by controlled atmosphere storage and modified atmosphere packaging. J Food Sci 64:328–331
123
