Gıda Mühendisliği Bölümü Yayın Koleksiyonu

Bu koleksiyon için kalıcı URI

https://hdl.handle.net/20.500.12885/1715

Listeleniyor 1 - 20 / 56

Recovery of Biobutanol from Aqueous Streams by Pervaporation Using Ionic Liquid Based Membranes
(SPRINGER HEIDELBERG, 2023) Erdoğan, Derya; Hasanoğlu, Ayça
Butanol as a biofuel, can be produced by ABE (acetone-butanol-ethanol) fermentation. Pervaporation is a promising process, especially for the separation of biofuels from aqueous mixtures such as ABE mixtures which consists of 3:6:1 ratio of ABE solvents and water around 97%. In this study, ionic liquid-based membranes were developed for the recovery of butanol from aqueous mixtures. The active layer providing the selectivity was formed by using polydimethylsiloxane (PDMS) and 1-butyl-3-methylimidazolium bis(trifluoromethylsulfonyl)imide ([bmim][Tf2N]) ionic liquid (IL). Porous polyvinylidenefluoride (PVDF) and polytetrafluoroethylene (PTFE) films were used as the support layers. Two different types of membranes were prepared, in which IL was mixed into PDMS and cast as a thin film on the support layer, and IL was impregnated into the pores of the support layers. The effects of feed concentration and temperature on separation performance were investigated. In addition, the membranes were prepared with and without IL, and the effect of IL on membrane performance was investigated. In general, an increase in flux and selectivity values was observed with the addition of IL in PDMS. Butanol selectivities in pervaporation experiments with different process parameters were found between 24.7 and 61.3 when PTFE support layer was used and between 22.5 and 48.6 when PVDF support layer was used. Especially with the use of IL in the membrane, the fluxes increased 2.5-5 times, resulting in a significant increase in fluxes. As a result, it has been shown that PDMS+IL/PVDF and PDMS+IL/PTFE membranes can be used for effective butanol recovery by pervaporation.
Production of low protein and gluten-free cookies for phenylketonuria (PKU) and/or celiac patients
(Czech Academy of Agricultural Sciences, 2021) Parlak, Özen; Dündar, Ayşe Neslihan
The aim of this study was to analyse the production of gluten-free, low protein cookies, which can easily be consumed by celiac and phenylketonuria (PKU) patients. The formula was adopted to prepare the control cookies (without dried fruits) from maise starch, stabilisers, salt, sodium bicarbonate, protein-reduced milk powder, and sunflower oil. Different cookies were made by adding raisins (R), dried black currants (Cu), dried dates (D), dried apples and cinnamon (A) separately. In cookies, two different stabilisers were calculated according to starch weight [pectin (P): 0.15%, glycerol monostearate (GMS, G): 0.4%]. The effects of stabilisers and dried fruits on the physicochemical and sensory properties of cookies were investigated. The protein content was significantly higher (P < 0.05) in the cookies including R with pectin (PR), Cu with pectin (PCu), and A with pectin (PA). The amount of phenylalanine (Phe) was significantly higher (P < 0.05) in PR. The values of dietary fibre were the highest in the A cookies, while the lowest values appeared in the control (C). In the sensory evaluation (appearance, tasting properties, and affordability), it was found that PD (pectin with dries dates) was chosen as the best cookie (P < 0.05).
Quality retention in pumpkin powder dried by combined microwave-convective drying
(Springer, 2021) İzli, Gökçen; Yildiz, Gulcin; Berk, Senel Ecem
Three distinct drying methods, microwave drying (MWD), convective drying (CVD) and microwave-convective drying (MWCVD) with a grinding process were applied to obtain pumpkin powder. The effects of CVD (60, 70 & 80 °C), MWD (100 & 200 W) and MWCVD (100 W-60 °C, 100 W-70 °C, 100 W-80 °C, 200 W-60 °C, 200 W-70 °C, and 200 W-80 °C) applications on the physicochemical properties (water activity, bulk, tapped & particle densities, porosity, flowability, cohesiveness, swelling capacity, water holding capacity and water solubility index), color values (L*, a*, b*, C, αo and Δe), bioactive compounds (5-Hydroxymethyl-2-furfural (HMF), total phenolic content (TPC) and antioxidant capacity (DPPH and ABTS)) of the eleven pumpkin fruit powders were compared. The MWCVD, namely pumpkin powders dried at 200 W–80 °C resulted in shorter drying times with high‐quality dried pumpkin powders. The bulk, tapped and particle densities of pumpkin powders at 200 W-80 °C by MWCVD were 0.56, 0.66 and 1.74 g/cm3, respectively. These values are indicators of the good porosity (61.82%) of pumpkin powders. In addition, the highest TPC (1277.08 mg GA/100 g dw) and ABTS (126.99 ± 3.31 µmol Trolox/g dw) was observed for microwave-convective dried pumpkin powders at 200 W-80 °C. On the other hand, the lowest HMF level (10.12 ± 1.78 mg/kg dw) was found for the pumpkin poowders dried by MWCVD at 200 W-80 °C. In overall, dried pumpkin powders by a MWCVD method can be employed to acquire a high-quality food material along with an enhanced physicochemical properties, color and bioactive components.
Physicochemical and Morphological Properties of European Cranberrybush Powder Manufactured by Freeze Drying
(Taylor and Francis Ltd., 2021) Taskin, Onur; İzli, Gökçen; Izli, Nazmi
This study investigated the rehydration, water activity, pH, Brix, color, bulk density, tapped density, flowability, cohesiveness, wettability, solubility values, and microstructures of freeze-dried European cranberrybush powders. Additionally, experimental freeze-drying data were coupled to nine thin-layer models, and the logarithmic model was chosen to estimate the moisture ratio of European cranberrybush. The pH and Brix values were measured between 3.0–3.2 and 40.33–52.00 for different powder sizes, respectively. A significant difference was observed for the water activity values of different powders that were classified into different powder sizes (P [removed]500 µm” powder size. According to the all scanning electron microscopy images, skeletal-like structures formed on the surfaces.
Monitoring environmental microbiological safety in a frozen fruit and vegetable plant
(Sociedade Brasileira de Ciencia e Tecnologia de Alimentos, SBCTA, 2021) Cinar, Aycan; Onbaşı, Elif
Ensuring food safety is becoming progressively important in frozen foods due to increased demand and consumption worldwide. The Environmental Monitoring Program (EMP) shall support daily operational activities and monitor the lack of process hygiene & sanitation actions to achieve food safety. The aim of this study was implementation of EMP in the frozen fruit and vegetable factory to identify the place that allows for pathogen/indicator microorganism growth and create preventive actions to reduce or eliminate the risk of cross-contamination. A total of 400 swab samples, Zone 1 (n = 228), Zone 2 (n = 90), Zone 3 (n = 52), Zone 4 (n = 30) were examined for E. coli and Coliform, Total Plate Count (TPC), yeast and mold and environmental Listeria spp. The percentage of satisfying target value before vs after the implementation of EMP was 82% vs. 100% for E. coli, 61% vs. 86% for Coliforms, 48% vs. 77% for TPC and 63% vs. 80% for yeast & mold respectively for Zone 1. Environmental Listeria was not determined in any of the zones. Integration of EMP to food safety management systems is essential to prevent outbreaks, recalls and economic losses. In addition to depending on the developing technologies, EMP should be supported with new corrective actions.
Total phenolic and antioxidant bioaccessibilities of cookies enriched with bee pollen
(John Wiley and Sons Inc, 2021) Dündar, Ayşe Neslihan
The purpose of this study was to investigate the use of bee pollen (BP; 5%, 10%, 15%) as a functional ingredient in cookies. Evaluation of physicochemical and sensory properties with total phenolic content (TPC) and antioxidant capacities in extractable, hydrolyzable, and bioaccessible fractions of enriched cookies was studied. With the addition of BP, carbohydrate content of the cookies decreased, while ash, total protein and total fat content, spread ratio (SR), the browning index, and hardness of the cookies increased. TPC of the enriched cookies were determined as 352.70–401.13 mg/100 g, of which 92.27%–93.16% were hydrolyzable phenolic content, and only 8.55%–9.26% of the TPC were bioaccessible. In addition, the cookies produced with the addition of BP were accepted in terms of their sensory properties. In the light of the information obtained, it can be said that BP is an ingredient that can improve the quality criteria while improving the functional properties of the cookies. Practical applications: There is limited information about functional and physico-chemical properties of pollen-fortified cookies. There are scarcely any studies in the literature on the hydrolyzable and bioaccessible of TPC and antioxidant capacity in pollen (none in products with pollen). In this study, the cookies were fortified with BP and the physico-chemical, sensory attributes, extractable, hydrolyzable, and bioaccessible of TPC, antioxidant capacities (two different methods; ABTS and DPPH) of the developed products were evaluated.
Dynamics of carob flour contents and palm stearin/palm olein ratios in cocoa carob cream production‒a new product development
(John Wiley and Sons Inc, 2021) Aydemir O.; Sarıcaoğlu, Furkan Türker; Atalar İ.
A new cocoa carob cream was developed and textural, rheological, and sensorial characteristics of the product were investigated. Three different carob flour (7.5%, 10%, and 12.5%) and palm stearin/palm olein mixture ratios (3.5/96.5%, 5/95%, and 6.5/93.5%) were used in laboratory-scale model manufacturing. The accelerated oil separation (AOS), water activity, spreadability and stickiness values in cocoa carob creams ranged from 6.27% to 12.80%, 0.274 to 0.309, 113 to 1,122 gs, −77.5 to −436 gs, respectively. As the palm stearin content increased and palm olein content decreased, spreadability, stickiness, apparent viscosity, yield stress K′, K″, G′, G″, Aα values increased, however, AOS, Casson plastic viscosity and n′ and n″ values decreased. The palm oil mixture ratio had more effect on the characteristics of the cocoa carob cream than carob flour content. It is concluded that the most preferred cocoa carob cream by panelists has 10% carob flour and 5/95% palm stearin/palm olein ratio. Novelty impact statement: Cocoa carob cream has been developed as a new product. Cocoa carob creams were acceptable by panelists based on sensory evaluation. Ten percent carob flour and 5/95% palm stearin/palm olein ratio provided the best textural, rheological, and sensory results in the production of cocoa carob cream.
Evaluation of high intensity ultrasound pre-treatment effects on the physical properties and bioactive compounds of convective dried quince samples
(Bellwether Publishing, Ltd., 2021) İzli, Gökçen; Yildiz G.
This work was undertaken to evaluate the impact of high-intensity ultrasound (HUS) pre-treatment on some quality characteristics of convective-dried (CVD) quince fruit pieces at different temperatures (50, 60, 70, and 80 °C). CVD quince samples at 70°C with a 15 min HUS pre-treatment showed the lowest water activity (0.36 ± 0.02). On the other hand, the quince fruit samples exposed to 15 min HUS pre-treatment shrank significantly (P < .05) especially when combined with convective drying at 70°C. The dried quince samples with no HUS pre-treatment exhibited the most condense and denser porous texture. While the lowest antioxidant capacity (AOC) was described for dried quince samples at 50°C with no HUS pre-treatment (2.58 μmol TE/g dry–weight), the highest AOC was determined for the dried quince samples exposed to HUS pre-treatment for 15 min at 70 °C (7.08 μmol TE/g on dry basis). Among the HUS-treated quince samples, the highest vitamin C content was found for the CVD quince samples at 70°C with 15 min HUS pre-treatment (43.79 mg/100 g on dry weight.). In overall, HUS is a promising pre-treatment as shown in current work by its efficiency for better preservation of CVD quince quality in terms of physical and chemical characteristics.
Effects of chia seed on chemical properties and quality characteristics of regular and low-fat crackers
(Sociedade Brasileira de Ciencia e Tecnologia de Alimentos, SBCTA, 2021) Dündar, Ayşe Neslihan; Aydin E.; Yildiz E.; Parlak O.
As a direct consequence of understanding the importance of the relationship between health and food, the interest in healthy recipes has increased. In the present study, wheat flour was used to replace chia seed (CS) in the cracker formulation (control) at levels of 10, 20, and 30% (w/w) and fat content was reduced by 25, 50, and 75% for the production of low-fat crackers. The physicochemical, textural, sensorial properties of the crackers were investigated. It was determined that CS had high a dietary fiber (38.7%), protein (21.78%), and fat (28.69%) content. The cracker sample containing 25% fat and 30% chia seed had the highest amounts of protein (14.49%) and dietary fiber (16.70%). CS could provide positive effects on health in terms of its high fiber content and low carbohydrate value. Six different fatty acids (FAs) were determined in the cracker samples. By reducing fat and increasing chia seed amount; oleic, linoleic, α-linolenic increased compared to the control sample, whereas the palmitic acid amount decreased significantly. According to the sensorial evaluation, the crackers were acceptable. It was also determined that CS was a suitable supplementation for low-fat products.
Mechanical, barrier, thermal, and microstructural properties of poly (lactic acid) and gelatin–beeswax emulsion bi-layer films
(John Wiley and Sons Inc, 2021) Pirinç, Fatma Tuba; Dağdelen, Adnan Fatih; Sarıcaoğlu, Furkan Türker
In this study, biodegradable bi-layer films from poly (lactic acid) (PLA) and bovine gelatin (BG)–beeswax emulsion were produced. PLA film was used as first layer, while BG containing beeswax at 0, 0.25, 0.50, 0.75, and 1% was the second layer, and optical, mechanical, barrier, thermal, and microstructural properties were characterized. The increasing beeswax concentration significantly increased the color difference (ΔE) and opacity of films, whereas decreased the light transmittance. Although tensile strength (TS) values decreased with the addition of beeswax, elongation at break (EAB) values increased. The highest oxygen permeability was observed from PLA film and production of bi-layer film significantly decreased the oxygen permeability. Microstructural images of bi-layer films containing 0.25 and 0.50% beeswax had good compatibility; however, increasing beeswax concentration to 0.75 and 1% weakened the interfacial adhesion of layers. PLA coated with BG–beeswax emulsions enhances the suitability of PLA films for food packaging applications. Novelty impact statement: Poly (lactic acid) film was coated with gelatin–beeswax emulsion films to produce bi-layer films with low oxygen permeability. Gelatin–beeswax emulsion as outer layer improved the oxygen barrier properties of inner PLA layer. The production of PLA–gelatin/beeswax emulsion bi-layer films could be valuable for food packaging applications due to low water vapor and oxygen permeability.
Farklı Kurutma Uygulamalarının Armut Meyvesinin Bazı Kalite Özellikleri Üzerine Etkileri
(2018) İzli, Gökçen
Bu çalışmada; mikrodalga-sıcak hava kombinasyonu kurutma yönteminin küp ve halka şeklinde hazırlanan armut meyvelerinin renk parametreleri, toplam fenolik madde miktarı ve antioksidan kapasitesi değerleri üzerine etkileri tespit edilmiştir. Laboratuvar tipi mikrodalga-sıcak hava fırını kullanılarak gerçekleştirilen denemelerde iki farklı mikrodalga gücü (90W ve 160W) ve üç farklı kurutma sıcaklığı (55, 65 ve 75?C) uygulanmıştır. Tüm kurutma koşullarından elde edilen örneklerin renk değerleri istatistiksel açıdan önemli ölçüde farklı bulunmuştur. Uygulanan mikrodalga gücü ve kurutma sıcaklığının artması ile armut örneklerinin L* (parlaklık) değerlerinde azalma, a* (yeşillik(-)/kırmızılık(+)) değerinde ise artış meydana gelmiştir. Taze armut örneklerinin renk parametrelerine en yakın değerler halka şeklinde hazırlanıp 160W-55?C uygulaması ile kurutulan örneklerden (?e=9,90) elde edilmiştir. En yüksek toplam fenolik madde miktarı (164,75 mg GA/100g K.M.) halka kesim şekli ve 160W-65?C uygulamasında belirlenirken, en yüksek antioksidan kapasite değeri taze örnekte (5,13 ?mol trolox/g K.M.) saptanmıştır. Bu çalışmada, uygulanan kurutma parametreleri ve kesim şeklinin ürün kalitesini doğrudan etkilediği belirlenmiştir. Özellikle halka şeklinde kesilerek kurutulan armut örneklerinden hem renk değerleri hem de toplam fenolik madde miktarı açısından daha başarılı sonuçlar elde edilmiştir.
Convective Drying Kinetics and Quality Parameters of European Cranberrybush
(2018) Taşkın, Onur; İzli, Gökçen; İzli, Nazmi
In this research, the effects of convective drying (60, 70, 80 and 90 °C) techniques on the drying kinetics, color, antioxidant capacity and total phenolic content of European cranberrybush were investigated in detail. To choose the best thin-layer drying models for the drying treatments, 10 mathematical models were compared for the experimental data. Depending on the evaluation by statistical tests, the Midilli et al model was determined to be the best suitable model to explain the drying behavior of European cranberrybush samples. All of the colorimetric parameters were influenced by drying temperatures. Antioxidant capacity and total phenolic content values of European cranberrybush samples displayed a significant reduction at low-temperature levels (60 and 70 °C) with regard to those at high-temperature levels (80 and 90 °C). In addition, the correlation analysis between antioxidant capacity and total phenolic content exhibited a high degree of correlation (R2 = 0.8656).
GIDA İŞLEME TESİSLERİNDE LISTERIA MONOCYTOGENES VE MÜCADELEDE YENİ YAKLAŞIMLAR
(2018) Altuntaş, Seda; Korukluoğlu, Mihriban
Listeria monocytogenes, bağışıklığı baskılanmış bireylerde gastrointestinal problemler, nörolojik bozukluklar ve sepsis gibi ciddi semptomlara ve yüksek ölüm oranına sahip bir gıda patojenidir. Listeriosisin ölümle sonuçlanma oranı yaklaşık %25, hastaneye kaldırılma oranı ise %95'in üzerindedir. Bu nedenle günümüzde hâlâ artan bir gıda güvenliği sorununu teşkil etmektedir. Olumsuz koşullarda uzun süre hayatta kalabilme ve biyofilm oluşturabilme yeteneği nedeniyle gıda işleme ortamlarının en önemli sorunlarından biri L. monocytogenes ile mücadeledir. Bu mücadelede başlangıç olarak, mikroorganizmanın kontaminasyon yollarını ve yayılmasına katkıda bulunan faktörleri bilmek, antilisterial uygulamalar için gerekli olmaktadır. Bu bilgiler doğrultusunda, doğru tasarlanan tesis, ekipman, temizlik ve sanitasyon programları, personel eğitimi ve sürekli izleme sistemleri ile etkili bir mücadele sağlanabilmektedir. Ancak artan bilinç ve önlemlere rağmen, bazı gıda işletmelerinde ve gıdalarda L. monocytogenes tespit edilmektedir. Bu durum Listeria ile mücadelede antimikrobiyel bileşiklerin kullanımı, ohmik ısıtma, yüksek basınç uygulaması ve soğuk plazma tekniği gibi birçok yeni yaklaşımların gerekliliğini ortaya koymaktadır. Bu derlemede, L. monocytogenes in gelişme koşulları, olası kontaminasyon kaynakları, gıda işleme tesislerinde yapılması gereken uygulamalar ve mücadelede yeni yaklaşımların verilmesi amaçlanmıştır
A response surface methodology study on the efects of some phenolics and storage period length on vegetable oil quality: change in oxidation stability parameters
(2014) Karaman, Safa; Toker, Ömer Said; Öztürk, İsmet; Yalçın, Hasan; Kayacıer, Ahmed; Doğan, Mahmut; Sağdıç, Osman
In the present study, response surface methodology was conducted for the determination of efects of some phenolics (gallic acid, ellagic acid, and quercetin) on some stability parameters of mixed oil prepared with sunfower and hazelnut oils (50:50, v/v). In this respect, peroxide value (PV), free fatty acids (FFAs), p-anisidine value, induction period, and refractive index of mixed oil were investigated. Predictive regression equations were constructed for the estimation of each studied parameter (R2 > 0.861). Te storage period caused a signifcant increase in the peroxide value, FFAs, p-anisidine, and refractive index values of the mixed oil, while it decreased the induction period value of oil (P < 0.01). Te addition of gallic acid signifcantly retarded oxidation (P < 0.05), and in general gallic acid and quercetin were found to be efective for preserving oil against oxidation.
Investigation of fatty acid composition and trans fatty acid formation in extracted oils from French-fried potatoes and classifcation of samples using chemometric approaches
(2015) Yıldırım, Elif; Toker, Ömer Said; Karaman, Safa; Kayacıer, Ahmed; Doğan, Mahmut
The present study investigates fatty acid composition and trans fatty acid formation in oils extracted from French-fried potatoes, which were produced in the laboratory and collected from diferent restaurants. Potatoes were fried at 180 °C at diferent frying periods (1, 7, 13, 19, 25, and 31 min) and the fatty acid composition of the extracted oils was determined. Principal component analysis and hierarchical cluster analysis were used to characterize and classify the samples. Four major fatty acids were identifed in the samples, namely palmitic acid, stearic acid, oleic acid, and linoleic acid. Linolelaidic acid (C18:2 trans) was detected in the oil samples extracted from potatoes fried in margarine. Tree principal components (PCs) and 4 main clusters were obtained from the chemometric analysis, which characterized the samples. Tree PCs were found to be explanatory of more than 84.96% of the total variability in the data set.
Probiyotik Escherichia coli Suşu Nissle 1917
(2017) Altuntaş, Seda; Korukluoğlu, Mihriban; Altuntaş, Volkan
Probiyotikler yeterli miktarda alındıklarında, konakçının sağlığı üzerine olumlu etkileri bulunan, patojen olmayan canlı mikroorganizmalardır. Probiyotik mikroorganizmalar genellikle fermente süt ürünleri veya gıda takviyeleri gibi gıda maddelerinin bileşenleridir. Gıda endüstrisinde, yaygın olarak Laktik Asit Bakterileri (LAB) kullanılmaktadır. Hayvan besleme, yem endüstrisi ve ilaç sanayiinde ise laktik asit bakterilerinin yanı sıra diğer patojen olmayan ve sağlık üzerine olumlu etkileri bulunan mikroorganizmalar da (Sacchromyces boulardii ve Escherichia coli Nissle 1917 ) kullanılır. Bu çalışmada; probiyotik E. coli suşu Nissle 1917'nin kökeni, tıbbi tarihi, mikrobiyolojik ve genetik özellikleri, biyolojik aktiviteleri, güvenirliliği ve toksikolojik yönü ele alınmıştır. Bunlara ek olarak EcN (E.coli Nissle 1917) ile yapılan klinik deneyler de özetlenecektir
Sıcaklık ve Farklı Kıvam Verici Maddelerin Ketçabın Reolojik Özellikleri Üzerine Etkileri
(2018) Bıldır, Büşra; Demircan, Hüseyin; Oral, Rasim Alper
Bu araştırmada, ketçap formülasyonuna üç farklı (guar gam, ksantan gam ve modifiye mısır nişastası) hidrokolloid ayrı ayrı ilave edilerek laboratuvar ortamında ketçap üretimi yapılmıştır. Hidrokolloid eklenerek üretilen ketçap numunelerinin reolojik davranışları, Anton Paar MCR 302 marka/model reometre cihazı kullanılarak 1-100 s-1 kayma hızı aralıklarında ve geniş bir sıcaklık aralığında (10- 50 °C) incelenmiştir. Elde edilen sonuçlar, reometre cihazının yazılım programı (RheoCompass 1.21) kullanılarak Power Law ve Herschel–Bulkley modellerine uygun olarak modellenmiştir. Ön denemeler sonucunda ketçabın salçadan üretilmesi durumunda ideal kıvam değerinin sağlanmasında (guar gam ve ksantan gam için) kıvam arttırıcının %1 oranında eklenmesinin uygun olduğu görülmüştür. Modifiye mısır nişastasının %1’lik ilavesinin ise yapısal bütünlüğü ve sürekliliği sağlamadığı da görülmüştür. Sıcaklığın ketçabın reolojik özellikleri üzerine en iyi etkinin guar gam tarafından sağlandığı belirlenmiştir. Bu sonuçlar ketçap üretiminde üretim koşullarını belirlemek ve standardizasyonu sağlamak için önem arz etmektedir.
The presence of mold in chestnut honey: Is a risk factor to health?
(Parlar Scientific Publications, 2020) Cinar, Aycan
In this study, 45 chestnut honey obtained from five different locations in Turkey were examined. The mycological results recovered 11 mold genera consisting of 79 isolates including Absidia spp., Alternaria spp., Aspergillus spp., Aureobasidium spp., Byssochlamys spp., Cladosporium spp., Eurotium spp., Fusarium spp., Mucor spp., Paecilomyces spp., Penicillium spp. The most predominant genera were Penicillium with 41.77 % followed by Aspergillus spp., 26.59 %, Cladosporium spp., 12.66 %. Among Penicillium spp. on chestnut honey, the predominantly isolated species were P. echinulatum, P. glabrum and P. variable, respectively. The presence of molds such as Aspergillus, Alternaria, Fusarium and Penicillium isolated from chestnut honey, which are potential mycotoxin producers, might cause a risk to public health. Also, these molds may trigger indigestion, allergic respiratory illness and adverse effects on the immune system. On the other hand, the total number of mold ranged from 0 to 61 CFU/g. Our results show that Chestnut honey samples in this study have good microbiological and hygienic quality. © 2020 Parlar Scientific Publications. All rights reserved.
Determination of antimicrobial activities of different flower honeys
(Bursa Uludag University, 2020) Cinar, Aycan
Honey is highly nutritious, and a functional food rich in bioactive components. The biological activity of honey differs according to its botanical origin, geographic properties, and climate characteristics. Therefore, it is necessary to handle the monofloral and multifloral honey produced in our country in a comprehensive manner. Adopting the understanding of displacement of natural preservatives with synthetic ones enables the exploration of alternative uses of honey. For this purpose, in our study, the antimicrobial activity of lavender, lemon, thyme and multifloral honey were determined and compared with each other. According to the results obtained, it was found that multifloral honey has higher antimicrobial activity than monofloral honey, but lemon honey which is one of the monofloral honey types, shows strong inhibition against microorganisms tested, and thyme honey had the weakest antibacterial effect. Antimicrobial activity (except for Bacillus cereus DSM 4312) was found to be strongest against bacterial then yeast and then mold in all honey varieties. In addition, we found that that the most resistant bacteria statistically was B. cereus DSM 4312, while the most sensitive bacteria was Klebsiella pneumoniae ATCC 700603 and Pseudomonas aeruginosa ATCC 35032. © 2020 Uludag Aricilik Dergisi. All rights reserved.
Effect of high pressure homogenization on microstructure and rheological properties of hazelnut beverage cold-set gels induced glucono-δ-lactone
(Academic Press, 2021) Gul, O.; Sarıcaoğlu, Furkan Türker; Atalar, I.
In this study, high pressure homogenized (HPH) hazelnut beverage samples were acidified with glucono-?-lactone (GDL) and rheological, structural and gel strength properties of the cold-set gels were characterized. Hazelnut beverage at a concentration of 10 g 100 mL?1 was treated with HPH up to 150 MPa pressure and then mixed with GDL (2 g 100 mL?1). Gelation of hazelnut beverages was observed with small deformation oscillatory measurements during 150 min. Hazelnut beverages acidified with GDL displayed shear thinning behavior due to decreasing viscosity with increasing shear rate, however, HPH led to an increase in apparent viscosities of cold set hazelnut beverage gels. Cold set hazelnut beverages were characterized as weak gel-like macromolecular dispersions due to storage modulus (G?) was higher than loss modulus (G?). Angular frequency dependence of complex modulus (G*) was studied to measure the strength of the cross-linking protein network of suspension systems by calculating a constant order of relaxation function (?) and concentration-dependent stiffness parameter (A?). This study revealed for the first time that hazelnut proteins can form good gel structures with acidification, and gel properties can be improved by HPH treatment. © 2021 Elsevier Ltd

Güncel Gönderiler