applied sciences

Article The Effect of on the Quality Properties of Tarhana

Nermin Ta¸so˘gullarıand Ömer ¸Sim¸sek*

Department of Engineering, University of Pamukkale, 20017 Denizli, Turkey; [email protected] * Correspondence: [email protected]; Tel.: +90-258-296-3015

 Received: 27 May 2020; Accepted: 3 July 2020; Published: 10 July 2020 

Featured Application: Irradiation is a useful application to preserve tarhana by preventing microbiological risks and pest formation. An irradiation dose of 5 kGy and below can be applied for the preservation of the tarhana without quality loss.

Abstract: Tarhana is a traditional food produced by the fermentation, drying and grinding of dough prepared with wheat flour, yoghurt, various vegetables and spices. Microbiological risks and pest formation are the major problems encountered during the storage of tarhana. In this study, the effect of irradiation was determined in order to eliminate microbiological risks and pest formation while preserving the quality features during the storage of tarhana. Depending on the irradiation dose, microbial inhibition occurred in tarhana samples, and the maximum protection was achieved with 10 kGy. Nevertheless, doses of 2.5 and 5 kGy inhibited the growth of Bacillus cereus. Additionally, all irradiation doses prevented pest formation. The consistency coefficient of soups prepared with irradiated tarhana samples decreased depending on the irradiation doses. There was no difference in 2,2-diphenyl-1-picrylhydrazyl radical scavenging activity and total phenol content in the control with irradiated tarhana samples. However, the 10 kGy irradiated tarhana sample included higher thiobarbituric acid reactive substances. In conclusion, irradiation was applied for the first time to preserve tarhana by reducing the microbiological risk and preventing pest formation. Accordingly, a 5 kGy irradiation dose was recommended, with which the tarhana rheology was affected slightly.

Keywords: tarhana; food irradiation; microbiological safety; pest control;

1. Introduction Traditional fermented are a precious resource as they provide inexpensive, practical and convenient nutrients in the modern world under the threat of . Tarhana is a traditional fermented food that is prepared to consume as an instant soup by cooking a quantity of a dough powder in hot water [1,2]. It has nutritious and easy-to-digest properties, as well as having gained importance for infant nutrition in recent years [2,3]. Although there are slight differences in the production of tarhana, the tarhana dough is prepared by mixing wheat flour, yoghurt, sourdough and various vegetables and spices (tomato, red pepper, onion, mint, salt, etc.), and the dough is subsequently dried and ground after fermentation [1,4]. This fermented food is traditionally stored in a textile pouch, but plastic packages are preferred to avoid volatile loses [5]. However, it is difficult to keep the tarhana from moisture absorption, resulting in microbiological risks and pest formation problems during storage [6]. In fact, Turantas and Kemahlıoglu [7] showed the survival of the molds and some pathogenic such as E. coli O157:H7, S. aureus, S. typhimurium and B. cereus during the fermentation and storage period of tarhana. Additionally, aflatoxins ranging from 0.7–16.8 µg/kg were determined at 23.2% of 138 collected tarhana samples, whereas 29 samples contained Aflatoxin B1 (AFB1) ranging from

Appl. Sci. 2020, 10, 4749; doi:10.3390/app10144749 www.mdpi.com/journal/applsci Appl. Sci. 2020, 10, 4749 2 of 10

0.2–13.2 µg/kg [8]. Irradiation may be one of the possible solutions to reduce the risk of microbiological and pest encroachment during the storage of tarhana [9]. The use of irradiation [9–11], which involves the exposure of food to gamma and X rays to ensure quality and safety, has gained importance in recent years due to the large increase in foodborne diseases. Food irradiation is one of the prescribed methods for the control of the significant losses that can occur during the storage and distribution of products due to , parasites and insects [9,11]. The high-energy rays applied to food systems stop the vitality of microorganisms or larvae in food by causing damage to their DNA. This sterilization of the food without the use of heat has led to the technique being referred to as “cold sterilization” [9]. The International Atomic Energy Agency (IAEA) concluded that energy beams emitted from food irradiated with doses below 60 kGy, with gamma rays from -60 and cesium 137, were less than 5 MeV in strength and could be considered insignificant [12]. The present study aims to determine the effect of irradiation on the quality and characteristics of tarhana to avoid microbiological risks and pest formation. Accordingly, the microbiological, chemical and physical effects of irradiation applied to packaged dried tarhana to prevent microbiological, physical and chemical losses during its storage is investigated.

2. Materials and Methods

2.1. Material Five different flour type tarhana samples were purchased from local markets located in Denizli, Turkey in October 2015, which were blended and subsequently packaged in 5 kg plastic bags (LDPE, 30 52 cm, 60 micron thickness) for storage. × 2.2. Irradiation and Storage Conditions of Tarhana Samples The tarhana samples were irradiated by the GAMMAPAK Sterilization Ind. & Trd. Inc. (Tekirda˘g, Turkey) with three different doses: 2.5, 5 and 10 kGy. Three packages of tarhana were irradiated for each dose, and three packages of tarhana were used as controls without irradiation. All the irradiated and control tarhana samples were stored in their packages at 25 ◦C for 5 months.

2.3. Microbiological and Pest Formation Analysis The microbial analysis of tarhana samples (10 g) was carried out at the end of every month over 5 months of storage. The total aerobic mesophilic bacteria (TAMB) counts during the storage of tarhana samples were enumerated [13] on Plate Count Agar (PCA; Merck Co. Darmstadt, Germany) after 48 h incubation at 30 ◦C. The yeast grown in the tarhana samples was determined with a Dichloran Rose Bengal Chlortetracycline agar (DRBC; Merck Co., Darmstadt, Germany) at 25 ◦C after 5 days [14], and the Bacillus cereus was enumerated on Bacillus cereus agar (Merck Co., Darmstadt, Germany) supplemented with polymyxin B and trimethoprim at 30 ◦C after 72 h [15]. Pest analysis was performed by periodically observing the remaining material after 100 g of tarhana samples were sieved through a 2500 micron mesh during storage.

2.4. Acidity Degree, pH and Moisture Analysis The acidity degree of the tarhana doughs was measured according to the TS2282 [5]. Accordingly, 10 g tarhana was homogenized with WiseStir mixer (HS-50A, DAIHAN, Korea) with 50 mL of 67% neutralized ethanol (Sigma-Aldrich, St. Louis, MO, USA). Then, the mixture was filtered (cellulose filter paper, Fisher Scientific, Loughborough, UK) and finally titrated with 0.1 M NaOH (Sigma-Aldrich, USA). The spent NaOH amount was multiplied by 5 to reach the acidity value of the tarhana dough samples. The pH value of the dough samples was determined as follows: 25 mL of distilled water was added to a 5 g sample and homogenized using a WiseStir mixer (HS-50A, DAIHAN, Korea). Distilled water was added to make a homogenous mixture of 50 mL, and the pH values were measured Appl. Sci. 2020, 10, 4749 3 of 10 using a pH meter (Eutech Instruments, Singapore). The moisture contents of tarhana samples during storage were measured according to AOAC (Association of Official Analytical Chemists) [16].

2.5. Color and Viscosity Analysis The color properties of the tarhana samples were determined with using the Hunter-Lab Mini Scan XE color measurement device (Reston, VA, USA, ABD). In order to determine the viscosity values of tarhana, 10 g of tarhana sample was weighed and a 10% (w/v) tarhana–water mixture was prepared by adding 90 mL of pure water. This mixture was heated in a mechanical shaker and boiled for 20 min. The consistency coefficient (K) and flow behavior index (n) values of the tarhana–water mixtures were measured by a Brookfield programmable DV-II+ (Middleboro, MA, USA) viscometer. Samples were transferred to the sample container (Brookfield Accessories, SC4-13R) connected to a circulating water bath at 70 ◦C at 19 different speeds (5, 8, 10, 15, 17, 20, 25, 30, 35, 40, 50, 60, 70, 90, 105, 120, 140, 160 and 180 rpm) and K and n values were determined.

2.6. 2,2-Diphenyl-1-Picrylhydrazyl (DPPH) Radical Scavenging Analysis The ability to scavenge the DPPH radical of tarhana samples was estimated by the methods of Wang et al. [17] and Fratianni et al. [18], respectively, with slight modifications. Aliquots of 0.1 mL tarhana extracts obtained from 1 g tarhana with 10 mL methanol (Sigma-Aldrich, USA) were mixed with 5 mL of 0.1 mM (prepared in methanol) DPPH radical in a test tube. The mixture was allowed to stand for 20 min at room temperature before the absorbance was measured at 517 nm spectrophotometrically (PG Instruments, Lutterworth, UK). The scavenging activity was calculated by the following equation:

Scavenging activity% = ((Absorbance of Blank Absorbance of Sample))/(Absorbance of Blank) 100 − × The “absorbance of blank” is the absorbance of the control reaction (containing all reagents except the test compound), and the “absorbance of sample” is the absorbance of the read test compound (517 nm).

2.7. Total Phenolic Content (TPC) Analysis The tarhana samples were analyzed for total phenolic content by using the Folin–Ciocalteus assay after 1 g of tarhana sample was homogenized with 10 mL of methanol (Sigma-Aldrich, USA) and kept overnight for extraction at refrigeration temperature. The results were expressed in mg gallic acid (Sigma-Aldrich, USA) in 100 g of tarhana. [19].

2.8. Thiobarbituric Acid Reactive Substances (TBARS) Analysis TBARS were determined using the extraction method described by Witte et al. [20]. TBARS numbers were calculated as mg of malonaldehyde per kg of tarhana (mg malondialdehyde/kg).

2.9. Statistical Analysis All the experiments were carried out in triplicate. The microbiological, chemical and physical analyses of the tarhana samples, as well as the irradiation dose application, storage duration and intergroup differences, were determined a one-way analysis of variance using the MINITAB 17.1.0 program (State College, PA, USA).

3. Results and Discussion

3.1. Viable Organism Content of Tarhana Samples during Storage In all irradiation doses applied, the formation of pests in tarhana samples could be prevented. However, in the control group without irradiation, a significant number of pests were found (Figure1a). These results showed that irradiation was effective at preventing pest formation. The major problem Appl. Sci. 2020, 10, 4749 4 of 10

for dried tarhana during storage is pest formation, which is a spontaneous biological problem due to the developmentAppl. Sci. 2020, 10, x of FOR larval PEER eggsREVIEW over time if the tarhana is stored under unsuitable conditions4 of 10 with high moisture and temperature. This problem is recognized to cause economic losses for many dried 133 problem due to the development of larval eggs over time if the tarhana is stored under unsuitable 134foods conditions [3]. In this with study, high moisture to test the and eff temperatureectiveness of. This irradiation, problem is irradiated recognized and to cause control economic tarhana loss sampleses 135were for observed many dried at a foods constant [3]. In high this temperaturestudy, to test (25the effectiveness◦C). Normally, of irradiation, it is advised irradiated that tarhana and control should be 136stored tarhana under samples 20 ◦C withwere lowobserved humidity at a constant [2,6]. high temperature (25 °C). Normally, it is advised that 137 tarhanaThe irradiation should be store widelyd under and 20 distinctly °C with low reduced humidity the [2,6]. microbial load. However, microbiological 138activity increasedThe irradiation with extended widely and storage distinctly time reduced dependent the on microbial the irradiation load. However, dose applied, microbiological meaning that 139higher activity doses increased retarded with the extend microbialed storage growth time for dependent longer. The on TAMBthe irradiation amounts dose of tarhanaapplied, samplesmeaning were 140closely that related higher withdoses the retard applieded the irradiation microbial growth dose. Thefor longer TAMB. The content TAMB at amounts approximately of tarhana 7 log samples CFU/gr for 141control were samples closely wasrelated reduced with the substantially applied irradiation after irradiation dose. The (Figure TAMB1 contentb). However, at approximately the TAMB 7 amounts log 142 CFU/gr for control samples was reduced substantially after irradiation (Figure 1b). However, the significantly increased during storage (p < 0.05) for the 2.5 and 5 kGy irradiated tarhana samples. 143 TAMB amounts significantly increased during storage (p < 0.05) for the 2.5 and 5 kGy irradiated In 10 kGy irradiated samples, the TAMB counts remained below 1 log CFU/gr until the fifth month 144 tarhana samples. In 10 kGy irradiated samples, the TAMB counts remained below 1 log CFU/gr until 145of storage.the fifth Similarly,month of storage. the yeast Similarly, mold contentthe yeastof mold tarhana content samples of tarhana was samples considerably was considerably reduced at all 146irradiation reduced doses.at all irradiation Only the doses. 2.5 kGy Only irradiated the 2.5 kGy sample irradiated remained sample above remained 1 log above CFU /1gr. log Although CFU/gr. the 147yeast Although mold content the yeast of mold the 2.5content kGy of tarhana the 2.5 kGy sample tarhana reached sample the reached same the level same as level the as control the control group at 148the endgroup of at storage the end (p of >storage0.05), (p the > 0 amount.05), the a ofmount yeast of mold yeast remainedmold remained below below 3 log 3 log CFU CFU/gr/gr for for the the 5 kGy 149irradiated 5 kGy tarhana irradiated sample. tarhana The sample. lowest The amount lowest of yeastamount mold of wasyeast found mold inwas the found 10 kGy in irradiated the 10 kGy sample 150(Figure irradiated1c). After sample irradiation, (Figure 1 thec). AfterBacillus irradiation cereus (BC), the Bacillus content cereus was (BC) able content to be reduced was able below to be reduced 1 log CFU /gr 151at allbelow doses 1 applied.log CFU/gr For at the all doses control applied. tarhana For sample, the control the BCtarhana content sample reached, the BC 5 log content CFU /reachedgr after 5 log months. 152However, CFU/gr the after BC 5 contentmonths. increasedHowever, abovethe BC 1content log CFU increased/gr after above the first 1 log month CFU/gr of after storage the forfirst both month 2.5 and 153 of storage for both 2.5 and 5 kGy irradiated samples as well as after the third month of storage for the 5 kGy irradiated samples as well as after the third month of storage for the 10 kGy irradiated sample; 154 10 kGy irradiated sample; however, the BC content was significantly below 2.5 log CFU/for at both however, the BC content was significantly below 2.5 log CFU/for at both irradiated tarhana samples 155 irradiated tarhana samples (Figure 1d). These results indicate that irradiation is important for 156(Figure ensuring1d). These microbiological results indicate safety that in tarhana. irradiation In addition, is important while for a ensuringsimilar level microbiological of microbiological safety in 157tarhana. protection In addition, was provided while in a tarhana similar at level 2.5 ofand microbiological 5 kGy doses, more protection effective wasprotection provided was achieved in tarhana at 1582.5 andin the 5 kGy10 kGy doses, irradiated more tarhana effective sampl protectione. The effectiveness was achieved of irradiation in the 10 kGyis related irradiated with the tarhana microbial sample. 159The load effectiveness of foods [9,11] of irradiation. Indeed, tarhana is related is a fermented with the food microbial which includes load of substantial foods [9,11 amount]. Indeed,s of lactic tarhana 160is a fermentedacid bacteria food and yeast which, although includes some substantial of this flora amounts are reduced of lactic during acid drying bacteria [1,2]. and However, yeast, some although 161some spore of this-forming flora are bacteria reduced and during molds drying could be [1 ,2 contaminated]. However, some according spore-forming to the traditional bacteria drying and molds 162could conditions be contaminated [6–8]. These according microbiological to the results traditional suggested drying that conditions a minimum [ 65 –kGy8]. Thesedose is microbiologicalrequired to 163results eliminate suggested the majority that a minimum of fermenting 5 kGy and dose contaminating is required flora to eliminatein dried tarhana. the majority of fermenting and 164contaminating flora in dried tarhana.

16 8 Aa Aa Aa Aa Aa Aa 14 7 Ab ABb 12 6 ABb 10 5 Ab ABc 8 4 Bb Bc 6 3

TAMB log CFU/g logTAMB Cb

4 2 d Pest Formation (pcs/100 g) (pcs/100 Formation Pest Ba Ab 2 Cb Bb Bb Ab Ac 1 0 0 0 1 3 5 0 1 3 5 Storage (months) Storage (months)

Control 2,5 kGy 5 kGy 10 kGy Control 2,5 kGy 5 kGy 10 kGy

(a) (b)

Figure 1. Cont. Appl.Appl. Sci. 2020 Sci. ,201020,, 4749 10, x FOR PEER REVIEW 5 of 105 of 10

7 6

6 Aa 5 Aa Aa Aa Ba Ab Ba

5 4 Ba Log CFU/g Log 4 3 Bb Ca Ac Ab Ab Cb Ab Ac

Yeast Log CFU/g LogYeast 3 2 Bc

Db cereus Bacillus 2 Bc 1 d

1 0 0 1 3 5 0 1 3 5 Storage (months) Storage (months)

Control 2,5 kGy 5 kGy 10 kGy Control 2,5 kGy 5 kGy 10 kGy

(c) (d)

165 FigureFigure 1. The 1. The microbiological microbiological changes changes and and pestpest formation during during the the storage storage of irradiated of irradiated and andcontrol control 166 tarhanatarhana samples. samples. (a )(a Pest) Pest formation, formation, ((bb)) totaltotal aerobic mesophilic mesophilic bacteria bacteria (TAMB (TAMB),), (c) y (ceast) yeast and and(d) (d) 167 BacillusBacillus cereus cereuscounts. counts. Capital Capital letters letters represent represent thethe p < 0.050.05 level level of of statistical statistical difference difference between between the the 168 storagestorage times times of the of the tarhana tarhana samples, samples, while while the the lower-caselower-case letters letters show show the the p < p 0<.050.05 level level of statistical of statistical 169 differencedifference between between the the irradiation irradiation doses. doses.

1703.2. Physical3.2. Physical Changes Changes in Tarhanain Tarhana Samples Samples during During Storage Storage 171 TheThe irradiation irradiation doses doses applied applied had had a aslight slight eeffectffect on on the the pH, pH, acidity acidity degree degree and and moisture moisture content content 172of tarhanaof tarhana samples samples (Table (Table1). 1 However,). However, significant significant changes changes were were observed observed in in these these parameters parameters 173independent independent of irradiationof irradiation with with storage storage time.time. The pH pH of of the the tarhana tarhana samples samples increased increased during during the the 174 storage (p < 0.05). There were no differences between tarhana samples at the beginning of storage, storage (p < 0.05). There were no differences between tarhana samples at the beginning of storage, 175 but the pH increase was slower (p < 0.05) in the 5 and 10 kGy irradiated tarhana samples for later but the pH increase was slower (p < 0.05) in the 5 and 10 kGy irradiated tarhana samples for later 176 storage times. In contrast to the pH increase, the acidity degree of the tarhana samples decreased 177storage during times. storage In contrast(p < 0.05); to in theparticular, pH increase, in the thi therd month acidity of degree storage, of there the was tarhana a significant samples decrease decreased 178during in the storage acidity (p degree< 0.05); of inall particular,tarhana samples in the (p third < 0.05) month. There of w storage,as no difference there was during a significant storage for decrease the 179in theacidity acidity degree degree of tarhana of all tarhana samples samples with different (p < 0.05). irradiation There dose wass. noAs expected, difference the during moisture storage content for the 180acidity of tarhana degree increased of tarhana depending samples on with the di storagefferent time irradiation; in particular doses., in As the expected, third month, the the moisture amount content of 181of tarhanamoisture increased was increased depending significantly on the storagein the tarhana time; in samples particular, (p < in 0. the05). thirdMoreover, month, the the moisture amount of 182moisture content wass of increased 5 and 10 significantlykGy irradiated in tarhana the tarhana samples samples were (p low< er0.05). from Moreover, the beginning themoisture to the end contents of 183of 5storage. and 10 kGyDried irradiated tarhana is tarhanahygroscopic samples and has were a rapid lower moisture fromthe absorption beginning ability to the[2,3]. end Although of storage. 184Dried tarhana tarhana is traditionally is hygroscopic stored and in pouches has a rapid or commercial moisture absorptionpolyethylene ability bags [1 [,4],2,3 the]. Although pH increase tarhana and is 185 decreased acidity in addition to the increased moisture content might be the cause of microbial traditionally stored in pouches or commercial polyethylene bags [1,4], the pH increase and decreased 186 development and pest formation, as shown above. acidity in addition to the increased moisture content might be the cause of microbial development and 187pest formation,Table as 1 shown. The pH, above. acidity degree* and moisture content changes during the storage of 188 irradiated and control tarhana samples. 189 Table 1. The pH, acidity degree * and moisture content changes during the storage of irradiated and control tarhanaSamples samples.Months pH Acidity Value* Moisture Content (%) SamplesControl Months0 4.28 pH ± 0.00Da 23 Acidity.25 ± 4.11 ValueAa * Moisture17.17 ± 0.05 ContentCa (%) Ca Aa Bab Control 01 4.284.87 ±0.00 0.28Da 1823.25.40 ± 2.524.11 Aa 16.9517.17 ± 0.24 0.05 Ca ± ± ± 13 4.875.46 ±0.28 0.57CaDb 1118.40.71 ± 0.822.52Aa Aa 18.4416.95 ± 0.24Bc0.24 Bab ± Db ± Aa ± Bc 3 5.46 0.57 Db 11.71 0.82Aa 18.44 Bbc0.24 5 6.16± ± 0.51 11.40 ± 1±.67 18.98 ± 0.15± 5 6.16 0.51 Db 11.40 1.67 Aa 18.98 0.15 Bbc 2,5 kGy 0 4.20± ± 0.00Ca 20.92 ± 2±.86Aa 17.14 ± 0.21±Ca 2.5 kGy 0 4.20 0.00 Ca 20.92 2.86 Aa 17.14 0.21 Ca 1 5.08± ± 0.16Ca 17.20 ± 0±.85Aa 16.97 ± 0.25±Ba 1 5.08 0.16 Ca 17.20 0.85 Aa 16.97 0.25 Ba ± ± ± 3 5.57 0.03 Cb 12.45 1.32 Aa 18.16 0.42 Bb ± ± ± 5 5.88 0.56 Cb 10.43 0.36 Aa 18.32 0.36 Bbc ± ± ± Appl. Sci. 2020, 10, x FOR PEER REVIEW 6 of 10

3 5.57 ± 0.03Cb 12.45 ± 1.32Aa 18.16 ± 0.42Bb 5 5.88 ± 0.56Cb 10.43 ± 0.36Aa 18.32 ± 0.36Bbc 5 kGy 0 4.18 ± 0.01Ba 22.57 ± 1.66Ba 16.87 ± 0.13Ba Appl. Sci. 2020, 10, 4749 1 4.83 ± 0.04Ba 19.35 ± 1.80Ba 16.76 ± 0.21Aab 6 of 10 3 5.11 ± 0,03Bb 12.33 ± 0.66Ba 17.65 ± 0.22Ac 5 5.45 ± 0.14Bb Table 1.10Cont..70 ± 0.04Ba 17.70 ± 0.38Abc 10 kGy 0 4.15 ± 0.01Aa 21.36 ± 0.59Ba 16.98 ± 0.17Aa Samples Months pH Acidity Value * Moisture Content (%) 1 4.54 ± 0.06Aa 21.71 ± 1.01Ba 16.64 ± 0.25Aab 5 kGy 0 4.18 0.01 Ba 22.57 1.66 Ba 16.87 0.13 Ba ± ± ± 31 5.21 4.83 ± 0.360.04Ab Ba 13.4319.35 ± 0.46Ba1.80 Ba 18.0916.76 ± 0.190.21Ac Aab ± ± ± 3 5.11 0,03 Bb 12.33 0.66 Ba 17.65 0.22 Ac 5 5.68 ± 0±.25Ab 10.55 ± 0.62±Ba 18.36 ± 0.13±Abc 5 5.45 0.14 Bb 10.70 0.04 Ba 17.70 0.38 Abc 190 ± ± ± 10 kGy 0 4.15 0.01 Aa 21.36 0.59 Ba 16.98 0.17 Aa 191 Capital letters represent the p < 0.05 level± of statistical difference± between the storage ±times of the 1 4.54 0.06 Aa 21.71 1.01 Ba 16.64 0.25 Aab ± ± ± 192 tarhana samples, while3 the lower-case 5.21 letters0.36 showAb the p <13.43 0.05 level0.46 ofBa statistical difference18.09 0.19 betweenAc ± ± ± 193 the irradiation doses. 5 5.68 0.25 Ab 10.55 0.62 Ba 18.36 0.13 Abc ± ± ± 194 *: TheCapital acidity letters values represent of the the tarhana p < 0.05 levelsamples of statistical were given difference according between to the the storage standard times TS8222 of the tarhana [5] due samples, to 195 thewhile amount thelower-case of NaOH letters used showto neutraliz the p < 0.05e the level acidity of statistical of 10 g difference tarhana between extracted the with irradiation 67% doses.ethanol. *: The acidity values of the tarhana samples were given according to the standard TS8222 [5] due to the amount of NaOH used to neutralize the acidity of 10 g tarhana extracted with 67% ethanol. 196 3.3. Color Changes in Tarhana Samples During Storage

197 3.3.The Color effect Changes of irradiation in Tarhana on Samplesthe color during of tarhana Storage is also of interest. In this sense, the effect of strong 198 should be evaluated in terms of the color components. The L value of the tarhana The effect of irradiation on the color of tarhana is also of interest. In this sense, the effect of strong 199 samples increased at the initial storage and stabilized after the third month. The rate of L value of ionizing radiation should be evaluated in terms of the color components. The L value of the tarhana 200 tarhana increased depending on the irradiation dose applied, but there was no significant difference samples increased at the initial storage and stabilized after the third month. The rate of L value of 201 in the L value between the samples in terms of doses and storage time (Figure 2a). The whitening at tarhana increased depending on the irradiation dose applied, but there was no significant difference 202 the end of the first month observed in this study is a common problem encountered in the storage of in the L value between the samples in terms of doses and storage time (Figure2a). The whitening at 203 tarhana. The main factor here may be the loss of color due to the effect of light. The “a” value slightly the end of the first month observed in this study is a common problem encountered in the storage 204 decreased during the storage. This might be related to oxygen or light contact rather than the effect of tarhana. The main factor here may be the loss of color due to the effect of light. The “a” value 205 of irradiation. However, the decline rate of the “a” value of tarhana samples was dependent on slightly decreased during the storage. This might be related to oxygen or light contact rather than the 206 radiation dose, where the 10 kGy dose did reduce faster than the other doses (Figure 2b and c). In effect of irradiation. However, the decline rate of the “a” value of tarhana samples was dependent on 207 contrast, the “b” value of the tarhana samples increased in the first month and remained stable for a radiation dose, where the 10 kGy dose did reduce faster than the other doses (Figure2b,c). In contrast, 208 further four months. Tarhana has a characteristic yellowish color resulting from the paprika used in the “b” value of the tarhana samples increased in the first month and remained stable for a further four 209 the ingredients, which is important for consumer perception [2]. These results clearly showed that months. Tarhana has a characteristic yellowish color resulting from the paprika used in the ingredients, 210 irradiation has no detrimental effect on the color quality of tarhana samples, especially in terms of which is important for consumer perception [2]. These results clearly showed that irradiation has no 211 whitening, due to the loss of pigments arising from the paprika used in the production. detrimental effect on the color quality of tarhana samples, especially in terms of whitening, due to the 212 loss of pigments arising from the paprika used in the production.

100 50 90 80 40

70 AaAa AaAaAaAa AaAaAaAa AaAa 60 Ba Ba Ba Ba 30 50 AaAa Aab Ab Ba Ba Aa Bb BCa 40 20 BCaBabBCc Ca Ca Ca

Redness Redness (a) Cb Lightness (L)Lightness 30 20 10 10 0 0 0 1 3 5 0 1 3 5 Storage (months) Storage (months)

Control 2,5 kGy 5 kGy 10 kGy Control 2,5 kGy 5 kGy 10 kGy

(a) (b)

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50

50 40

40 30 Aa AaAaAa AaAbAbAb AaAbAbAb AaAaAaAa 30 20 Aa AaAaAa AaAbAbAb AaAbAbAb Yellowness (b)Yellowness AaAaAaAa 20

10 Yellowness (b)Yellowness

10 0 0 1 3 5 Storage (months)0 0 1 3 5 Storage (months) Control 2,5 kGy 5 kGy 10 kGy

Control 2,5 kGy 5 kGy 10 kGy (c)

213 (c)

214 FigureFigure 2. 213The 2. Thecolor color changes changes during during the the storage storage of irradiatedof irradiated and and control control tarhana tarhana samples. samples. (a ()a Lightness) Lightness L, 215 (b) rednessL, (b) redness+a, (c )+a yellowness, (c) yellowness+b. +b Capital. Capital letters letters represent represent the the p p< <0.05 0.05 levellevel ofof statistical difference difference 216 betweenbetween the214 storagethe storage times timesFigure of the of 2 the tarhana. The tarhana color samples, changessamples, while during while the the lower-casethe lower storage-case letters of lettersirradiated show show the and the p control< p 0.05< 0.05 level tarhana level of samples. (a) Lightness 217 statisticalof statistical215 difference difference betweenL, between(b the) redness irradiation the +airradiation, (c doses.) yellowness doses. +b. Capital letters represent the p < 0.05 level of statistical difference 216 between the storage times of the tarhana samples, while the lower-case letters show the p < 0.05 level 2183.4. 3.4. Rheological Rheological217 Properties Properties ofof Tarhanaof statistical Tarhana Samples differenceSamples during During between Storage Storage the irradiation doses. 219 TheThe consistency consistency coe coeffifficientscients of of soups soups prepared prepared with with tarhana tarhana powderspowders decreaseddecreased dramatically dramatically 218 3.4. Rheological Properties of Tarhana Samples During Storage 220depending depending on theon the irradiation irradiation dose dose applied applied because because the the consistency consistency coecoefficientfficient of the unirradiated 221tarhana tarhana sample sample219 was was higher higherThe than thanconsistency the the irradiated irradiated coeffi samples cientssamples of during during soups storage. storage.prepared However,However, with tarhana 10 kGy kGy powders irr irradiatedadiated decreased dramatically 222tarhana tarhana samples samples220 were weredepend less less viscousing viscous on (pthe (p< irradiation0.05)< 0.05) than than otherdose other applied 2.5 2.5 and and 5b5ecause kGykGy irradiatedirradiated the consistency tarhana coefficientsamples samples of the unirradiated 223(Figure (Figure3). However, 3).221 However, theretarhana wasthere nosample was significantly no was significant higher consistent thanly consisten the behavior irradiatedt behavior between samples between the 2.5 during and the 5 2storage. kGy.5 and irradiated 5However, kGy 10 kGy irradiated 224samples. irradiated The222 consistencysamples. tarhana The coe consistencyffi samplescient of coefficient unirradiatedwere less ofviscous unirradiated samples (p < increased 0 sample.05) thans in increased other contrast 2. 5in with and contrast the5 kGy irradiated with irradiated the tarhana samples 225tarhana irradiated samples.223 tarhana Briefly, (Figuresamples. the irradiation 3 Briefly). However,, the destructively irradiation there was destructively aff noected significant theviscosity affectedly consisten the ofthe viscosity tarhanat behavior of samplesthe tarhana between ina the 2.5 and 5 kGy 226dose-dependent samples in224 a manner. doseirradiated-dependent This mightsamples. manner be relatedThe. This consistency might with the be coefficient relateddegradation with of theunirradiatedof the degradation chain structuressample of thes increased chain of the in contrast with the 227 structures of the amylose and amylopectin fractions of starch, which are mainly responsible with amylose and amylopectin225 irradiated fractions tarhana of starch, samples. which Briefly are mainly, the irradiation responsible destructively with hydration affected in tarhana. the viscosity of the tarhana 228 hydration in tarhana. It was commented that gamma radiation may contribute to molecular changes It was commented226 thatsamples gamma radiationin a dose may-dependent contribute manner to molecular. This mightchanges be and related the fragmentation with the degradation of of the chain 229 and the fragmentation of starch, leading to a progressive reduction in the molecular size of amylose starch, leading227 to a progressivestructures reduction of the amylose in the molecular and amylopectin size of amylose fractions and of amylopectin starch, which by randomare mainly responsible with 230 and amylopectin by random cleavage of the glycosidic chains and consequently changes to the cleavage of the228 glycosidic hydration chains in andtarhana. consequently It was commented changes tothat the gamma structural radiation and physicochemical may contribute to molecular changes 231 structural and physicochemical characteristics of starch [21]. However, the consistency coefficient of characteristics229 of starch and [21 the]. However, fragmentation the consistency of starch, coeleadingfficient to ofa progressive tarhana samples reduction was in in the the range molecular size of amylose 232 tarhana samples was in the range reported by Ibanoglu and Ibanoğlu [22] except for the 10 kGy reported by Ibanoglu and Ibano˘glu[22] except for the 10 kGy irradiated tarhana sample. 233 irradiated230 tarhana andsample. amylopectin by random cleavage of the glycosidic chains and consequently changes to the 231 structural and physicochemical characteristics of starch [21]. However, the consistency coefficient of 16 232 tarhana samples was in the range reported by IbanogluAa and Ibanoğlu [22] except for the 10 kGy 14 Ba

233) irradiated tarhana sample. n 12 Ca Da 16 10 Ab Aa Ab ABbBa Bb 14 Bc 8 ) Bb Bb n Bb 6 12 Ca Ac Da 4 10 Bc Bd Ab Ab Bc ABb Consistency Consistency (Pa.Scoefficient Bb Bb Bc 2 8 Bb Bb

0 6 Ac 0 1 3 5 4 Bc Bd

Storage (months) Bc Consistency Consistency (Pa.Scoefficient 2

0 Control 2,5 kGy 5 kGy 10 kGy 234 0 1 3 5 Figure 3. The consistency coefficient of soups prepared with using irradiatedStorage (months) and control tarhana samples. Capital letters represent the p < 0.05 level of statistical difference between the storage times Control 2,5 kGy 5 kGy 10 kGy 234 Appl. Sci. 2020, 10, x FOR PEER REVIEW 8 of 10

235 Figure 3. The consistency coefficient of soups prepared with using irradiated and control tarhana 236 Appl.samples. Sci. 2020 Capital, 10, 4749 letters represent the p < 0.05 level of statistical difference between the storage times 8 of 10 237 of the tarhana samples, while the lower-case letters show the p < 0.05 level of statistical difference 238 between the irradiation doses. of the tarhana samples, while the lower-case letters show the p < 0.05 level of statistical difference 239 3.5. Antioxidantbetween theProperties irradiation of T doses.arhana Samples During Storage 240 3.5.The Antioxidant DPPH radical Properties scavenging of Tarhana activity Samples of tarhana during Storage samples, which were administered at 5 and 10 241 kGy irradiationThe DPPH doses radical at the scavenging beginning activityof storage, of was tarhana found samples, to be higher which than were that administered of the control at and 5 and 242 2.510 kGy kGy irradiated irradiation tarhana doses samples at the beginning (p < 0.05). of With storage, continuing was found months to be of higher storage, than no that difference of the controlwas 243 observedand 2.5 betweenkGy irradiated irradiated tarhana and samples control (p samples< 0.05). in With terms continuing of DPPH months radical of scavenging storage, no activity. difference 244 However, the scavenging activity of tarhana samples decreased with the storage time; in particular, was observed between irradiated and control samples in terms of DPPH radical scavenging activity. 245 a significant decrease in scavenging activity was observed in the third month (Figure 4a). Similarly, However, the scavenging activity of tarhana samples decreased with the storage time; in particular, 246 there was no significant difference in the total phenol content between tarhana samples after a significant decrease in scavenging activity was observed in the third month (Figure4a). Similarly, 247 irradiation and during storage. In the analyzes performed at the third and fifth months, only the 10 there was no significant difference in the total phenol content between tarhana samples after irradiation 248 kGy irradiated tarhana sample had a lower total phenol content (p < 0.05, Figure 4b). As expected, and during storage. In the analyzes performed at the third and fifth months, only the 10 kGy 249 the amount of TBARS in tarhana samples increased contrary to the decrease in antioxidant properties. irradiated tarhana sample had a lower total phenol content (p < 0.05, Figure4b). As expected, 250 After irradiation, the 5 and 10 kGy irradiated tarhana samples contained higher amounts of TBARS the amount of TBARS in tarhana samples increased contrary to the decrease in antioxidant properties. 251 (p < 0.05). During storage, the amount of TBARS in tarhana samples increased and more TBARS were After irradiation, the 5 and 10 kGy irradiated tarhana samples contained higher amounts of TBARS 252 detected in 10 kGy irradiated tarhana sample each time (Figure 4c). The major concern regarding the (p < 0.05). During storage, the amount of TBARS in tarhana samples increased and more TBARS were 253 adverse effect of irradiation in food systems is that it can trigger oxidation [9,11]. When evaluated in detected in 10 kGy irradiated tarhana sample each time (Figure4c). The major concern regarding the 254 this respect, it was seen that irradiation did not cause a decrease in the antioxidant capacity of adverse effect of irradiation in food systems is that it can trigger oxidation [9,11]. When evaluated in 255 tarhana. Even at the beginning of storage, higher levels of antioxidant properties were observed. This this respect, it was seen that irradiation did not cause a decrease in the antioxidant capacity of tarhana. 256 might be due to the effect of irradiation resulting in the release of the antioxidant substances. On the Even at the beginning of storage, higher levels of antioxidant properties were observed. This might be 257 other hand, irradiation did not significantly affect oxidation in tarhana samples. Higher oxidative due to the effect of irradiation resulting in the release of the antioxidant substances. On the other hand, 258 products were formed only when 10 kGy doses were applied. irradiation did not significantly affect oxidation in tarhana samples. Higher oxidative products were 259 formed only when 10 kGy doses were applied.

60 140

a a 120 a a 50 a a ab a b a b ab 100 40 a a abab 80 a 30 ab ab b 60 a a a a a 20 b b a a a b 40

b DPPH Scavenging (%)Scavenging DPPHActivity 10 TPC (mg Gallıc Acıd/100 g Tarhaha) Tarhaha) Acıd/100 g Gallıc TPC (mg 20

0 0 0 1 3 5 0 1 3 5 Storage (months) Storage (months)

Control 2,5 kGy 5 kGy 10 kGy Control 2,5 kGy 5 kGy 10 kGy

(a) (b)

Figure 4. Cont. Appl. Sci. 10 2020, , 4749 Appl. Sci. 2020, 10, x FOR PEER REVIEW 9 of 10 9 of 10

1.6 a ab 1.4 b b

1.2 a ab ab b 1 a 0.8 b b b a malondialdehyde/kg) malondialdehyde/kg) a 0.6 b b 0.4

TBARS (mg TBARS 0.2

0 0 1 3 5 Storage (months)

Control 2,5 kGy 5 kGy 10 kGy

(c)

Figure 4. 260The antioxidantFigure properties 4. The andantioxidant changes properties of irradiated and and changes control of tarhanairradiated samples and control during tarhana samples during storage. (a) 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, (b) total phenolic content 261 storage. (a) 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, (b) total phenolic (TPC), (c) thiobarbituric acid reactive substances (TBARS). Capital letters represent the p < 0.05 level 262 content (TPC), (c) thiobarbituric acid reactive substances (TBARS). Capital letters represent the p < of statistical difference between the storage times of the tarhana samples, while the lower-case letters 263 0.05 level of statistical difference between the storage times of the tarhana samples, while the lower- show the p < 0.05 level of statistical difference between the irradiation doses. 264 case letters show the p < 0.05 level of statistical difference between the irradiation doses. 4. Conclusions 265 4. Conclusions In this study, the use of irradiation for the preservation of tarhana was evaluated for the first time. Irradiation266 was successfullyIn this study, applied the to use reduce of irradiation microbiological for the risks preservation as well as pestof tarhana formation was in evaluated for the first tarhana during267 storage. time. Although Irradiation irradiation was successfully showed no applied adverse to eff reducect one the microbiological color and antioxidation risks as well as pest formation properties of268 tarhana, in it tarhana reduced during the consistency storage. Although coefficient irradiation of the soups showed prepared no fromadverse tarhana. effect on the color and Accordingly,269 instead antioxidation of the 10 kGy properties dose, it is recommendedof tarhana, it reduced to use 5the kGy consistency or lower dosescoefficient in order of the to soups prepared from preserve the quality270 featurestarhana. of Accordingly, tarhana. instead of the 10 kGy dose, it is recommended to use 5 kGy or lower doses in 271 order to preserve the quality features of tarhana.

Author Contributions:272 AuthorConceptualization, Contributions: Ö.¸S.;methodology, Conceptualization N.T.;, Ö.Ş. validation,.; methodology, N.T., N.T formal.; validat analysis,ion, N.T.;N.T., formal analysis, N.T.; investigation, N.T; resources, Ö.¸S.;data curation, N.T.; writing—original draft preparation, N.T.; writing—review 273 investigation, N.T; resources, Ö.Ş.; data curation, N.T..; writing—original draft preparation, N.T.; writing— and editing, Ö.¸S.;visualization, N.T.; supervision, Ö.¸S.;project administration, Ö.¸S.;funding acquisition, Ö.¸S. 274 review and editing, Ö.Ş.; visualization, N.T.; supervision, Ö.Ş.; project administration, Ö.Ş..; funding acquisition, All authors have read and agreed to the published version of the manuscript. 275 Ö.Ş. All authors have read and agreed to the published version of the manuscript. Funding: This research was funded by the University of Pamukkale, Scientific Research Projects Coordination Unit, grant number276 2016FEBE024.Funding: This research was funded by the University of Pamukkale, Scientific Research Projects Coordination 277 Unit, grant number 2016FEBE024. Conflicts of Interest: The authors declare no conflict of interest. 278 Conflicts of Interest: The authors declare no conflict of interest. References 279 References 1. Da˘glıo˘glu,O. Tarhana as a traditional Turkish fermented cereal food. Its recipe, production and composition. Nahrung 2000280, 44, 85–88.1. Dağlıoğlu, [CrossRef ] O. Tarhana as a traditional Turkish fermented cereal food. Its recipe, production and 2. Özdemir,281 S.; Gocmen, D.;composition. Kumral, A.Y. Nahrung A traditional 2000, 44 Turkish, 85–88. fermented cereal food: Tarhana. Food Rev. Int. 2007, 23, 107–121.282 2. [CrossRef Ö zdemir,] S.; Gocmen, D.; Kumral, A.Y. A traditional Turkish fermented cereal food: Tarhana. Food Rev. Int. 3. Kabak, B.;283 Dobson, A.D.W.2007, An 23,introduction 107–121. to the traditional fermented foods and beverages of Turkey. Crit. Rev.284 Food Sci.3. Nutr. Kabak,2011, 51 B.;, 248–260. Dobson, [A.D.W.CrossRef An][PubMed introduction] to the traditional fermented foods and beverages of Turkey. 4. Siyamo˘glu,B.285 Türk TarhanalarınınCrit. Rev. Food Yapılı¸sıve Sci. Nutr. Terkibi 2011 Üzerine, 51, 248 Ara¸stırma–260. ; Ege University, Faculty of Agriculture Press: Izmir,˙ 286 Turkey, 4. 1961;Siyamoğlu, pp. 1–75. B. Türk Tarhanalarının Yapılışı ve Terkibi Üzerine Araştırma; Ege University, Faculty of 5. Anonymous.287 TS 2282 TarhanaAgriculture Standard Press:; Turkish İzmir, Standard Turkey, 1961; Institute: pp. 1 Ankara,–75. Turkey, 2004. 6. Dalgic, A.C.;288 Belibagli,5. Anonymous. K.B. Hazard TS analysis 2282 Tarhana critical Standard control points; Turkish implementation Standard Institute in traditional: Ankara, Turkey, foods: 2004. A case study289 of tarhana6. D processing.algic, A.C.;Int. Belibagli, J. Food Sci.K.B. Technol.Hazard 2008analysis, 43, 1352–1360.critical control [CrossRef points] implementation in traditional foods: A 7. Turanta¸s,F.;290 Kemahlıoglu,case K.study Fate of oftarhana some processing. pathogenic Int. bacteria J. Food and Sci. moldsTechnol. in 2008 Turkish, 43, 1352 tarhana–1360. during fermentation291 and storage7. Turantaş, period. J. F.; Food Kemahlıoglu, Sci. Technol. K. Mysore Fate of2012 some, 49, 601–607.pathogenic [CrossRef bacteria][ andPubMed molds] in Turkish tarhana during 292 fermentation and storage period. J. Food Sci. Technol. Mysore 2012, 49, 601–607. Appl. Sci. 2020, 10, 4749 10 of 10

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