Pekmez is a concentrated syrup-like food conventionally produced by vacuum evaporation process from sugar-rich fruits. In this study, the applicability of grape pekmez production by ohmic heating assisted vacuum evaporation (ΩVE) method was investigated. Conventional vacuum evaporation (CVE) and ΩVE methods were compared in terms of physicochemical properties, HMF (5-hydroxymethylfurfural) contents, rheological properties, and energy consumptions. ΩVE was run at four different voltage gradients (17.5, 20, 22.5, and 25 V/cm). Total process times for grape pekmez production were determined as 57, 28.5, 32, 39, and 50 minutes for CVE, ΩVE (25 V/cm), ΩVE (22.5 V/cm), ΩVE (20 V/cm) and ΩVE (17.5 V/cm), respectively. Energy consumption of CVE method was higher than ΩVE method for all voltage gradients. Energy efficiency increased as the voltage gradient increased. There was no significant difference between CVE and ΩVE methods for HMF contents. The results show that the ΩVE method could be an alternative to the CVE process for grape pekmez production.
AkbulutMÖzcanM. (2008).
Some physical, chemical, and rheological properties of sweet sorghum (Sorghum Bicolor (L) Moench) pekmez (molasses). International Journal of Food Properties11(1): 79–91.
2.
Aliyazicioglu R, Kolayli S, Kara M, Yildiz O, Sarikaya AO, Cengiz S, et al. (2009). Determination of chemical, physical and biological characteristics of some pekmez (molasses) from Turkey. Asian Journal of Chemistry 21(3): 2215–2223.
3.
AllaliHMarchalLVorobievE. (2009).
Effect of blanching by ohmic heating on the osmotic dehydration behavior of apple cubes. Drying Technology27(6): 739–746.
4.
AltanAMaskanM. (2005).
Rheological behavior of pomegranate (Punica granatum L.) juice and concentrate. Journal of Texture Studies36(1): 68–77.
5.
Ames JM. (1992). The Maillard Reaction. In: Hudson, BJF (Ed.) Biochemistry of Food Proteins. Boston, MA: Springer US; pp. 99–153.
6.
Anonymous. (2017). Türk Gıda Kodeksi Üzüm Pekmezi Tebliği. Başbakanlık Basımevi.
Ankara:
Resmi Gazete.
7.
AOAC. (2000). Official Methods of Analysis.
Gaithersburg, MD:
AOAC.
8.
BatuAAktanN. (1993).
Üzüm pekmezlerinde asit ve pH değerleri üzerinde bir araştırma. Gıda ve Yem4(1993): 38–43.
9.
BerkZ. (2018). Food Process Engineering and Technology.
Cambridge, MA:
Academic Press.
10.
BogdanovSMartinPLullmannC. (2002). Harmonised methods of the international honey commission. Swiss Bee Research Centre, FAM, Liebefeld.
11.
BoldajiMTBorgheiAMBeheshtiB, et al. (2015).
The process of producing tomato paste by ohmic heating method. Journal of Food Science and Technology52(6): 3598–3606.
12.
BozkurtHIcierF. (2009).
Rheological characteristics of quince nectar during ohmic heating. International Journal of Food Properties12(4): 844–859.
13.
BozkurtHIcierF. (2012).
Ohmic thawing of frozen beef cuts. Journal of Food Process Engineering35(1): 16–36.
14.
BrochierBMercaliGDMarczakLDF. (2016).
Influence of moderate electric field on inactivation kinetics of peroxidase and polyphenol oxidase and on phenolic compounds of sugarcane juice treated by ohmic heating. LWT74: 396–403.
CokgezmeO FSabanciSCevikMYildizHIcierF. (2017).
Performance analyses for evaporation of pomegranate juice in ohmic heating assisted vacuum system. Journal of Food Engineering207: 1–9.
17.
DarvishiHHosainpourANargesiFFadaviA. (2015).
Exergy and energy analyses of liquid food in an Ohmic heating process: a case study of tomato production. Innovative Food Science & Emerging Technologies31: 73–82.
18.
DarvishiHKhostaghazaMHNajafiG. (2013).
Ohmic heating of pomegranate juice: Electrical conductivity and pH change. Journal of the Saudi Society of Agricultural Sciences12(2): 101–108.
19.
DarvishiHKoushesh SabaMBehroozi-KhazaeiNNourbakhshH. (2020).
Improving quality and quantity attributes of grape juice concentrate (molasses) using Ohmic heating. Journal of Food Science and Technology57(4): 1362–1370.
20.
DarvishiHMohammadiPFadaviAKoushesh SabaMBehroozi-KhazaeiN. (2019).
Quality preservation of orange concentrate by using hybrid ohmic – Vacuum heating. Food Chemistry289: 292–298.
21.
DemirciSKM. (2006).
Effects of storage time and condition on mineral contents of grape pekmez produced by vacuum and classical methods. Tekirdağ Ziraat Fakültesi Dergisi3(1): 1–7.
22.
ErdoğrulÖ. (2008).
Pesticide residues in liquid pekmez (grape molasses). Environmental Monitoring and Assessment144(1–3): 323–328.
23.
FadaviAYousefiSDarvishiH, et al. (2018).
Comparative study of ohmic vacuum, ohmic, and conventional-vacuum heating methods on the quality of tomato concentrate. Innovative Food Science & Emerging Technologies47: 225–230.
24.
FazaeliMHojjatpanahGEmam-DjomehZ. (2013).
Effects of heating method and conditions on the evaporation rate and quality attributes of black mulberry (Morus nigra) juice concentrate. Journal of Food Science and Technology50(1): 35–43.
25.
GallyTRouaudOJuryVHavetMOgéALe-BailA, et al. (2017).
Proofing of bread dough assisted by Ohmic heating. Innovative Food Science & Emerging Technologies39: 55–62.
26.
HaldenKDe AlwisAAPFryerPJ. (2007).
Changes in the electrical conductivity of foods during ohmic heating. International Journal of Food Science & Technology25(1): 9–25.
27.
HosainpourADarvishiHNargesiFFadaviA. (2014).
Ohmic pre-drying of tomato paste. Food Science and Technology International20(3): 193–204.
28.
IcierF. (2009).
Influence of Ohmic heating on rheological and electrical properties of reconstituted whey solutions. Food and Bioproducts Processing87(4): 308–316.
29.
IcierFYildizHBaysalT. (2006).
Peroxidase inactivation and colour changes during Ohmic blanching of pea puree. Journal of Food Engineering74(3): 424–429.
İçierFYildizHBaysalT. (2008).
Polyphenoloxidase deactivation kinetics during ohmic heating of grape juice. Journal of Food Engineering85(3): 410–417.
32.
KarababaEDeveli IsikliN. (2005).
Pekmez: A traditional concentrated fruit product. Food Reviews International21(4): 357–366.
33.
KayaA. (2001).
Rheology of mulberry pekmez. Journal of Texture Studies32(5–6): 335–342.
34.
KayaABelibağlıKB. (2002).
Rheology of solid gazıantep pekmez. Journal of Food Engineering54(3): 221–226.
35.
KayaAKoSGunasekaranS. (2011).
Viscosity and color change during in situ solidification of grape pekmez. Food and Bioprocess Technology4(2): 241–246.
36.
KnirschMCAlves dos SantosCMartins de Oliveira Soares VicentAAVessoni PennaTC. (2010).
Ohmic heating–a review. Trends in Food Science & Technology21(9): 436–441.
37.
KocaIHasbayIKaradenizBKocaAF. (2014).
Changes in the physicochemical and antioxidant characteristics of watermelon during pekmez production. Quality Assurance and Safety of Crops & Foods6(4): 411–418.
38.
KuşçuABulantekinÖ. (2016).
The effects of production methods and storage on the chemical constituents of apple pekmez. Journal of Food Science and Technology53(7): 3083–3092.
39.
LeizersonSShimoniE. (2005a).
Effect of ultrahigh-temperature continuous ohmic heating treatment on fresh orange juice. Journal of Agricultural and Food Chemistry53(9): 3519–3524.
40.
LeizersonSShimoniE. (2005b).
Stability and sensory shelf life of orange juice pasteurized by continuous ohmic heating. Journal of Agricultural and Food Chemistry53(10): 4012–4018.
41.
LoypimaiPMoongngarmAChottanomPMoontreeT. (2015).
Ohmic heating-assisted extraction of anthocyanins from black rice bran to prepare a natural food colourant. Innovative Food Science & Emerging Technologies27: 102–110.
42.
MercaliGDJaeschkeDPTessaroICMarczakLDF. (2012).
Study of vitamin C degradation in acerola pulp during ohmic and conventional heat treatment. LWT - Food Science and Technology47(1): 91–95.
43.
NguyenHTvan der Fels-KlerxHJIvan BoekelMAJS. (2017).
Acrylamide and 5-hydroxymethylfurfural formation during biscuit baking. Part II: Effect of the ratio of reducing sugars and asparagine. Food Chemistry230: 14–23.
44.
ParmarPSinghAKMeenaGSBoradSRajuPN. (2018).
Application of ohmic heating for concentration of milk. Journal of Food Science and Technology55(12): 4956–4963.
45.
RouxSCourelMBirlouez-AragonIMunicinoFMassaMPainJ-P. (2016).
Comparative thermal impact of two UHT technologies, continuous ohmic heating and direct steam injection, on the nutritional properties of liquid infant formula. Journal of Food Engineering179: 36–43.
46.
Ruan R, Ye X, Chen P, Doona CJ and Taub I. (2001). Ohmic heating. In: Richardson P. (Ed.) Thermal Technologies in Food Processing. Woodhead Publishing; pp. 241–265.
47.
SabanciSCevikMCokgezmeO FYildizHIcierF. (2019).
Quality characteristics of pomegranate juice concentrates produced by ohmic heating assisted vacuum evaporation. Journal of the Science of Food and Agriculture99(5): 2589–2595.
48.
SabanciSIcierF. (2017).
Applicability of ohmic heating assisted vacuum evaporation for concentration of sour cherry juice. Journal of Food Engineering212: 262–270.
49.
SabanciSIcierF. (2020).
Rheological behavior of sour cherry juices concentrated by ohmic and conventional evaporation processes under vacuum. Journal of Food Processing and Preservation44(10): e14832.
50.
SakrMLiuS. (2014).
A comprehensive review on applications of ohmic heating (OH). Renewable and Sustainable Energy Reviews39: 262–269.
51.
SengülMFatih ErtugayMSengülM. (2005).
Rheological, physical and chemical characteristics of mulberry pekmez. Food Control16(1): 73–76.
52.
SilvaRRochaRSGuimarãesJTBalthazarCFPimentelTCNetoRPC, et al. (2020).
Advantages of using ohmic heating in Dulce de Leche manufacturing. Innovative Food Science & Emerging Technologies65: 102475.
53.
SimsekAArtıkN. (2002).
Değişik meyvelerden üretilen pekmezlerin bileşim unsurları üzerine araştırma. Gıda27(6).
54.
SingletonVLRossiJA. (1965).
Colorimetry of total phenolics with phosphomolybdic-phosphotungstic acid reagents. American Journal of Enology and Viticulture16(3): 144–158.
55.
TokerOSDoganMErsözNBYilmazMT. (2013).
Optimization of the content of 5-hydroxymethylfurfural (HMF) formed in some molasses types: HPLC-DAD analysis to determine effect of different storage time and temperature levels. Industrial Crops and Products50: 137–144.
56.
VargheseKSPandeyMCRadhakrishnaKBawaAS. (2014).
Technology, applications and modelling of ohmic heating: A review. Journal of Food Science and Technology51(10): 2304–2317.
57.
VeríssimoMISGamelasJAFEvtuguinDVGomesMTSR. (2017).
Determination of 5-hydroxymethylfurfural in honey, using headspace-solid-phase microextraction coupled with a polyoxometalate-coated piezoelectric quartz crystal. Food Chemistry220: 420–426.
58.
YildizHBozkurtHIcierF. (2009).
Ohmic and conventional heating of pomegranate juice: Effects on rheology, color, and total phenolics. Food Science and Technology International15(5): 503–512.
59.
YoğurtçuHKamışlıF. (2006).
Determination of rheological properties of some pekmez samples in Turkey. Journal of Food Engineering77(4): 1064–1068.
