Total antioxidant capacity and phenolic content of pasteurized and UHT-treated cow milk samples marketed in Turkey

Peer reviewe

Drying of tomato pomace in daylight simulated photovoltaic-assisted drying system: Effects of daylight intensity and application mode

It was aimed to dry a by-product of tomato paste production (tomato pomace) by minimizing the losses valuable components and reducing energy consumption. In this concept, a daylight simulated photovoltaic-assisted dryer (DPVD) applying the daylight in different modes and intensities during drying was custom-designed. The effects of daylight applications on the change of some quality characteristics of tomato pomace and system performance characteristics were investigated, and the optimum drying condition was determined. The process conditions included the combination of three different daylight application modes (UV-blocked daylight via solar tube-DLST, DLST + LED, and LED) and three different daylight intensities (2,500, 7,500, and 10,000 lux). The drying was applied for 240 min at constant air temperature (60 degrees C) with an air velocity of 2 m/s. The moisture content and the water activity values of dried tomato pomace were 8.86 +/- 2.00% and 0.57 +/- 0.10%, respectively. The lycopene and beta-carotene losses after drying were determined as 68.36 +/- 4.32% and 65.66 +/- 4.33%, respectively. The energy and exergy efficiencies of the system were in the range of 19.56%-35.73% and 5.10%-17.05%, respectively. The optimum condition meeting the criteria of superior quality and high-performance characteristics was obtained by applying DLST at 7,500 lux (desirability 0.728). In the performance improvement studies, it has been concluded that all the energy required for the process could have been fulfilled as 100% from solar energy with the support of photovoltaic panels. In other words, it was demonstrated that the developed DPVD system could be used to dry the tomato pomace not only in terms of providing high food quality and safety, but also in terms of having high energy efficiency.The authors thank TUBTAK TOVAG and Ege universitesi BAP for financial supports to this study. This study was a part of the PhD thesis Sunlight Simulated and Photovoltaic Assisted Drying System Configuration, Performance Assessment and Investigation of Using for Drying of Tomato Pulp. The drying system was designed and set up in Project TUBITAK 119O132. The experimental design was applied within the scope of the Ege universitesi BAP project FDK-2019-20627. Author (Damla Bayana) thank to TUBTAK fellowship support of BIDEB 2211C program and YOK 100/2000 Renewable Energy Sources and Technologies fellowship program.TUBTAK TOVAG; Ege universitesi BAP; TUBTAK; TUBITAK [119O132]; Ege universitesi BAP project [FDK-2019-20627

Total Antioxidant Capacity and Phenolic Content of Pasteurized and UHT-Treated Cow Milk Samples Marketed in Turkey

In this study, UHT-treated (a total of 39 samples with 17 full-fat, 17 semi-fat and 5 skim milk) and pasteurized (5 full-fat) milk samples from different trademarks were obtained from national market chains, which constitute the majority of the Turkey’s pasteurized and UHT milk market. Total antioxidant capacities and phenolic contents of milk samples were determined by the 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and Folin-Ciocalteu (FC) methods, respectively. Mean total phenolic contents of milk samples ranged from 505.46±16.66 to 982.14±168.42 mg gallic acid equivalents (GAE)/L. Statistical results of the ABTS assay indicated that total antioxidant capacities in decreasing order were pasteurized [280.25±7.71 µM Trolox® Equivalent (TE)] > full-fat (240.30±15.71 µM TE) > skim (216.78±4.90 µM TE) > semi-fat (209.81±7.03 µM TE) milk samples. In general, total antioxidant capacity of milk samples determined by the Folin-Ciocalteu method increased with an increase in milk fat content. Antioxidant capacity of pasteurized milks determined by both methods was higher than UHT processed milks

Türkiye’de Satışa Sunulan UHT ve Pastörize İnek Sütü Örneklerinin Toplam Antioksidan Kapasitesi ve Fenolik Madde İçeriği

Bu çalışmada, Türkiye'deki pastörizasyon veya ultra yüksek sıcaklık (UHT) işlemi uygulanmış süt pazarının önemli bir bölümünü oluşturan farklı ticari markalardan UHT (17 tam yağlı, 17 yarım yağlı ve 5 yağsız olmak üzere toplam 39 numune) ve pastörize süt (5 tam yağlı) örnekleri ulusal market zincirlerinden toplanmıştır. Süt örneklerinin toplam antioksidan kapasiteleri ve fenolik içerikleri, sırasıyla 2,2'-azino-bis 3-etilbenzotiazol-6-sülfonik asit (ABTS) ve FolinCiocalteu (FC) yöntemleriyle belirlenmiştir. Süt örneklerinin toplam fenolik içeriği 505.46±16.66 ile 982.14±168.42 mg gallik asit eşdeğeri (GAE)/L arasında değişmiştir. ABTS yöntemiyle elde edilen verilerin istatistiksel analizi sonucunda örneklerin toplam antioksidan kapasitelerinin azalan sırayla pastörize (280.25±7.71 ?M Trolox®eşdeğeri, TE)> tam yağlı (240.30±15.71 ?M TE)> yağsız (216.78±4.90 ?M TE)> yarım yağlı (209.81±7.03 µM TE) süt örnekleri şeklinde olduğu belirlenmiştir. Genel olarak, süt yağı içeriğinin artışı Folin-Ciocalteu yöntemi ile belirlenen toplam antioksidan kapasite değerinin de artmasıyla sonuçlanmıştır. Her iki yöntemle belirlenen sütlerin antioksidan kapasite değerleri pastörize sütlerde UHT ile işlenmiş sütlere göre daha yüksek bulunmuşturIn this study, UHT-treated (a total of 39 samples with 17 full-fat, 17 semi-fat and 5 skim milk) and pasteurized (5 fullfat) milk samples from different trademarks were obtained from national market chains, which constitute the majority of the Turkey’s pasteurized and UHT milk market. Total antioxidant capacities and phenolic contents of milk samples were determined by the 2,2'-azino-bis (3-ethylbenzothiazoline-6-sulphonic acid) (ABTS) and Folin-Ciocalteu (FC) methods, respectively. Mean total phenolic contents of milk samples ranged from 505.46±16.66 to 982.14±168.42 mg gallic acid equivalents (GAE)/L. Statistical results of the ABTS assay indicated that total antioxidant capacities in decreasing order were pasteurized [280.25±7.71 µM Trolox® Equivalent (TE)] > full-fat (240.30±15.71 µM TE) > skim (216.78±4.90 µM TE) > semi-fat (209.81±7.03 µM TE) milk samples. In general, total antioxidant capacity of milk samples determined by the Folin-Ciocalteu method increased with an increase in milk fat content. Antioxidant capacity of pasteurized milks determined by both methods was higher than UHT processed milk

Mathematical modelling of vacuum ohmic evaporation process

Ohmic evaporation is a complex process in which heat and mass transfers take in place simultaneously. In this study, finite difference-FD and finite volume-FV models simulating the changes of temperature and water removed from tomato juice during the vacuum ohmic evaporation process (VOEP) were developed. Models considering the heat and mass transfer equations were combined. Experimental effective electrical conductivity and specific heat capacity relations were taken into account. For heating period, final temperature was predicted with errors of 3.4 ? 1.3 ?C and 0.7 ? 1.3 ?C, while the evaporation time prediction errors were 1.3 ? 1.6 min and - 2.1 ? 1.6 min for FV and FD models, respectively. It was concluded the effect of mixing was not important on temperature distribution for such a high consistency tomato paste compared to the heat generation effect during the ohmic evaporation process. The developed models could be used to predict process time, temperature history, and volume fraction at any time during the ohmic evaporation process.This research was supported financially by the Scientific and Technical Research Council of Turkey, TUBITAK, Project No: 217O069.Scientific and Technical Research Council of Turkey, TUBITAK [217O069

Comparative performance analysis of ohmic thawing and conventional thawing of spinach puree

Nowadays dietary habits of consumers have changed to more quick and easier but at the same time healthier meals. Therefore, ready-to-eat food production and home processing of such foods are gaining importance. Spinach is one of the main ingredients used in ready-to-eat baby foods, and it is produced in chopped, blanched, juice, and powder forms. Commonly ready-to-eat meals are sold frozen. Therefore, thawing process becomes an important processing step. Conventional thawing (CT) methods require a long process time and high-energy consumption. In the present study, frozen blanched spinach puree samples were thawed by ohmic thawing (OT) (10 V/cm, 15 V/cm). The thawing at 4 degrees C (refrigerator thawing) was selected as the control thawing method. The energetic and exergetic evaluations were compared. Accordingly, thawing times were shortened by about 70-80% with OT. The energy loss during the CT method was higher than the OT method. The most energy-efficient (64.2% +/- 4.0%) thawing condition was determined as 15 V/cm OT. In case of exergetic evaluation, the destroyed exergy value of the CT method was highest (19.0 +/- 2.0 kJ) while those of thawed with 10 and 15 V/cm were 5.8 +/- 0.7 and 3.8 +/- 0.4 kJ, respectively. Similar to energetic efficiency, OT with 15 V/cm had the highest exergy efficiency value (40.5% +/- 2.6%) while that of the CT method was 11.6% +/- 1.0%. The result of the present study indicated that the OT process could be an alternative thawing method to CT to improve energy efficiency. Practical applications As the ready-to-eat meal habit is becoming more common, processing of such foods is becoming more important. While preparing food, it is desired that the process to be done quickly, homogeneously, and efficiently. Usage of current food technologies to provide fast and homogeneous heating is becoming widespread. However, examining and evaluating their efficiency also emerges as an important issue. In this study, the use of OT, which is one of the current methods, for the thawing of spinach puree was investigated and the efficiency of OT in different voltage gradients was evaluated. In this way, it is thought that important data about the efficiency of the ohmic heating process, which utilization is increasing day-by-day, during the thawing process are obtained. It is thought that these data will contribute to future studies and contribute to the widespread dissemination of OT.Turkiye Bilimsel ve Teknolojik Arastirma Kurumu [2209-A]Turkiye Bilimsel ve Teknolojik Arastirma Kurumu, Grant/Award Number: 2209-