Ohmic heating assisted vacuum evaporation of pomegranate juice: Electrical conductivity changes

İçıer, Fılız; Yıldız, Hasan; Sabancı, Serdal; Çevik, Mutlu; Çokgezme, Ömer Faruk

doi:10.1016/j.ifset.2016.12.014

Cited by 79 publications

(55 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Unclassified

Order By: Relevance

“…The results indicated that the electric conductivity varied from 0.49 to 0.98 to 0.38 to 0.80 S/m for orange and grapefruit samples, respectively. At the vacuum pressure of −77.3 kPa, Icier, Yildiz, Sabanci, Cevik, and Cokgezme () stated that electrical conductivity of the pomegranate juice varied from 0.56 to 0.74 when voltage gradient changed from 7.5 to 12.5 V/cm (Icier et al., ). At this pressure, Sabanci and Icier () indicated that during the heating‐up period, the average electrical conductivity values of sour cherry juice changed from 0.67 to 0.70 S/m when voltage gradient changed from 10 to 14 V/cm (Sabanci & Icier, ).…”

Section: Resultsmentioning

confidence: 99%

“…The modeling of electrical conductivity of pacific whiting surimi paste (Yongsawatdigul, Park, & Kolbe, ), apple, and sour cherry juices (Icier & Ilicali, ) and orange juice concentrate (Icier & Ilicali, ) showed that voltage gradient did not affect the conductivity significantly. A linear model with temperature is commonly presented for electrical conductivity in the literature; this type of modeling has been recently reported even in vacuum conditions with a high value of R 2 (Icier et al., ).…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Ohmic Heating of Lemon and Grapefruit Juices Under Vacuum Pressure— Comparison of Electrical Conductivity and Heating Rate

Fadavi

Salari

2019

Journal of Food Science

View full text Add to dashboard Cite

Ohmic heating fundamentally depends on electrical conductivity. In this study, grapefruit and lemon juices were ohmically heated under vacuum conditions. The electrical conductivity was measured at voltage gradients (10, 20, and 30 V/cm) and vacuum pressure (0 [atmospheric pressure], −30, and −60 kPa) for four temperature ranges (30, 40, 50, and 60 °C), meanwhile the heating rate was also reported at the same level of pressure and voltage gradient. The electrical conductivity and heating rate considerably vary by voltage gradient relative to pressure. Grapefruit had considerably lower electrical conductivity (about 20%) relative to lemon juice for the same pressure–voltage gradient treatment, while the percent reduction of heating rate (grapefruit relative to lemon) varied from 19 to 32%. The multivariate linear regression of electrical conductivity, including temperature and voltage, was found to be a more suitable model. pH assessments showed that pressure significantly affected the pH of grapefruit and lemon juices (P < 0.01). The combination of different treatments, which created a shorter residence time, caused a greater decrease in pH.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Resultsmentioning

confidence: 99%

Ohmic Heating of Lemon and Grapefruit Juices Under Vacuum Pressure— Comparison of Electrical Conductivity and Heating Rate

Fadavi

Salari

2019

Journal of Food Science

View full text Add to dashboard Cite

show abstract

“…Temperature, current and voltage values were recorded by custom made microprocessor. Measurement methods of pH and TSS content are provided by Icier et al . in detail.…”

Section: Methodsmentioning

confidence: 99%

“…They reported that optimum voltage gradient determined by taking into account evaporation time, pH, colour and energy consumption was 14 V cm −1 . In a recent study of our group, ohmic heating was integrated to vacuum conditions for the purpose of using in evaporation process. They have applied the ohmic heating assisted vacuum evaporation (OVE) (180 mmHg absolute pressure) process at different voltage gradients (7.5, 10 and 12.5 V cm −1 ) to concentrate the pomegranate juice from 17.5% TSS content to 40% TSS content.…”

Section: Introductionmentioning

confidence: 99%

Quality characteristics of pomegranate juice concentrates produced by ohmic heating assisted vacuum evaporation

et al. 2018

Self Cite

View full text Add to dashboard Cite

BACKGROUND: Vacuum evaporation (VE) process is widely utilized in fruit juice evaporation to preserve quality attributes of final product. However, it has some disadvantages such as possible degradation of aroma components or volatile fatty acids due to long process time, and low energy efficiency of process. Pomegranate juice having 17.5% total soluble solid (TSS) content was evaporated to 40% TSS by ohmic heating assisted vacuum evaporation (OVE; 7.5, 10 and 12.5 V cm −1 ) and VE in the present study. The effects of the evaporation methods on pH, titratable acidity and colour values, antioxidant activity (AA), total monomeric anthocyanin (TMA), total phenolic content (TPC), hydroxymethylfurfural (HMF) and invert sugar content of pomegranate juice concentrates were compared. RESULTS:The colour properties, TMA, TPC and AA values of pomegranate juice concentrates evaporated by OVE were more influenced than those evaporated by VE. The degradation of sugars was minimized for OVE processes at high voltage gradients (10 and 12.5 V cm −1 ), and HMF content of pomegranate juice concentrated by OVE was lower than VE. CONCLUSION: It is thought that electrochemical reactions occurred because of the use of titanium electrodes during the OVE process caused these quality changes in pomegranate juice concentrates having high acidity. Hence, it was concluded that the utilization of relatively more electrochemically inert electrodes should be investigated in further studies to better evaluate the of influence of OVE method on quality attributes of different fruit juices.where subscript '0' indicated colour properties of raw material, and subscript 'i' indicated colour properties of juice concentrates. Statistical evaluationStatistical evaluations were performed by using SPSS 16.0 (IBM, USA) program. The difference between the effects of evaporation methods on colour properties, TPC, total and invert sugar content, TMA, HMF and AA were determined by using analysis of variance (ANOVA) test. The confidence interval was chosen as 95%.

show abstract

“…Ohmic heating can be used for different purposes in processing of food materials such as heating, pasteurization, cooking, sterilization, blanching, thawing, etc. (Bozkurt & Icier, 2010a, 2010b, 2010c; Içier et al, ; Icier, Yucel Sengun, Yildiz Turp, & Arserim, ; Icier, Cokgezme, & Sabanci, ; Icier, Yildiz, Sabanci, Cevik, & Cokgezme, ; Ozkan, Ho, & Farid, ; Palaniappan & Sastry, 1991a, 1991b; Roberts, Balaban, & Luzuriaga, ; Sensoy & Sastry, ; Wang & Sastry, ).…”

Section: Introductionmentioning

confidence: 99%

Effects of voltage gradient and fat content on changes of electrical conductivity of frozen minced beef meat during ohmic thawing

Çevik

İçıer

2018

J Food Process Engineering

Self Cite

View full text Add to dashboard Cite

Frozen minced beef meat samples having different fat contents of 2, 10, and 18% were thawed until their center temperature reached −1 °C in the ohmic thawing system. Ohmic thawing was conducted by applying different voltage gradients (10, 13, and 16 V/cm) at ambient temperature of 4 ± 0.5 °C. Effective electrical conductivity (EEC) values of the samples at −1 °C were 0.5774 ± 0.0558, 0.4231 ± 0.0510, and 0.3933 ± 0.0693 S/m for 2, 10, and 18% fat contents, respectively. The change of effective electrical conductivity with temperature was linear for temperature range of −18 °C/−9.5 °C while it was exponential for temperature range of −9.5 °C/−4 °C. Above −4 °C, the polynomial model was best model describing the change of EEC with temperature. Ohmic thawing process could be applied as an alternative novel technology for thawing of meat and meat products. It is thought that the results of present study would contribute valuable information to open literature. Practical applications Researchers have given attention on investigation of alternative thawing methods for foods in recent years. Ohmic thawing has high energy efficiency, causes low drip loss and does not produce any waste water. Since it is controlled by heat generation caused due to passing of alternative current through food, the information on change of its electrical conductivity is crucial. The minced beef sample has heterogeneous structure such as muscle, connective, and adipose tissues. Thus, its effective electrical conductivity (EEC) varies depending on its composition. In this study, the relations between temperature and EEC of minced beef samples having different fat contents were determined for four different temperature ranges existed during ohmic thawing at different voltage gradients. EEC was very low at temperatures below −4 °C, and then it sharply increased above this temperature. Results of present study would give valuable information to food industry for setting up industrial scale ohmic thawing systems for meat and meat products.

show abstract

Ohmic heating assisted vacuum evaporation of pomegranate juice: Electrical conductivity changes

Cited by 79 publications

References 31 publications

Ohmic Heating of Lemon and Grapefruit Juices Under Vacuum Pressure— Comparison of Electrical Conductivity and Heating Rate

Ohmic Heating of Lemon and Grapefruit Juices Under Vacuum Pressure— Comparison of Electrical Conductivity and Heating Rate

Quality characteristics of pomegranate juice concentrates produced by ohmic heating assisted vacuum evaporation

Effects of voltage gradient and fat content on changes of electrical conductivity of frozen minced beef meat during ohmic thawing

Contact Info

Product

Resources

About