Food Engineering / Gıda Mühendisliği
Permanent URI for this collectionhttps://hdl.handle.net/11147/12
Browse
8 results
Search Results
Article Tarıma Dayalı Sanayi Atıklarının Katı Kültür Fermantasyonu ile Değerlendirilmesi: Sürece Etki Eden Faktörlere Genel Bakış(Gıda Teknolojisi Derneği, 2015) Demir, Hande; Tarı, CananKatı-kültür fermantasyonu (KKF) batı ülkelerinin son yıllarda ilgisini çekmiş olan fakat doğu ülkeleri tarafından çok eski zamanlardan beri kullanılagelen bir teknolojidir. KKF, mühendislik ve çevresel açıdan bakıldığında birçok ürün ve biyolojik işlemin gelişimi için uygun bir yöntem olmakla birlikte, hâlihazırda derin kültür fermantasyonu ile rekabeti devam etmektedir. Bu derleme makalede KKF’nin tanımı, kısa tarihçesi, tarıma dayalı sanayi atık kullanımının avantajları ve kısıtları ile birlikte inert yataklar hakkında bilgi verilmektedir. Derlemenin önemli bir bölümünde ise inokülüm oranı, inkübasyon süre ve sıcaklığı, nem içeriği ve su aktivitesi, başlangıç pH’ı, parçacık büyüklüğü, karıştırma ve inokülüm türü gibi KKF işlemlerini etkileyen etkenler özetlenmiştir. Her bir etkenin KKF işlemleri üzerindeki etkisi teorik olarak detaylandırılmakla kalmayıp, aynı zamanda literatürde yer alan çalışmalar yardımıyla da tartışılmıştır. Bu makale KKF işlemleriyle ilgilenen araştırmacılara ışık tutacağı gibi tarıma dayalı sanayi atıklarına katma değer kazandırılması konusunda da üreticilere yol gösterecektir.Article Citation - WoS: 3Citation - Scopus: 5Assessing the Impact of Non-Thermal and Thermal Treatment on the Shelf-Life of Onion Juice(Czech Academy of Agricultural Sciences, 2018) Demir, Hande; Yıldız, Mustafa Kemal; Becerikli, İsmail; Ünlütürk, Sevcan; Kaya, ZehraOnion (Allium cepa L.) juice is a marinating agent for meat and fish marination and readily usable sauce for any meal that has onion in its formulation. This study aims to assess the microbiological and physicochemical changes in the onion juice processed by UV-C irradiation (0.5 mm sample depth, 30 min exposure time, 7.5 mW/cm(2) UV incident intensity) and conventional heat treatment (74.5 degrees C, 12 min) during its storage. Microbiological results showed processing by UV-C irradiation or heat treatment under optimum conditions extended the microbial shelf-life of untreated onion juice by minimum 6-times. Total colour change of heat-treated samples was lower than that of untreated and UV-C treated samples for 12 weeks. Also, pH, total titratable acidity, total soluble solids content, turbidity, NEBI and total phenolic content were monitored for 12 weeks. The results of this study will form scientific infrastructure for onion juice manufacturers to decide on the processing method with respect to its shelf-life.Article Citation - WoS: 13Citation - Scopus: 18Effect of Physicochemical Parameters on the Polygalacturonase of an Aspergillus Sojae Mutant Using Wheat Bran, an Agro-Industrial Waste, Via Solid-State Fermentation(John Wiley and Sons Inc., 2016) Demir, Hande; Tarı, CananBACKGROUND: Polygalacturonases (PGs) are valuable enzymes of the food industry; therefore it is of great importance to discover new and GRAS PG-producing microbial strains. In this study, PG enzyme produced from a high PG activity producer mutant Aspergillus sojae using wheat bran at the flask scale under pre-optimized conditions of solid-state fermentation (SSF) was biochemically characterized. RESULTS: The crude PG enzyme showed optimum activity in the pH range 4.0–5.0 and was stable in the pH range 3.0–7.0. The optimum temperature for the PG was 40 °C and it retained 99% of its activity at 50 °C. The mutant A. sojae PG could preserve more than 50% of its stability between 25 and 50 °C, both for 30 and 60 min, and was found to be stable in the presence of most of the tested compounds and metal ions. The inactivation energy (Ed) was determined as 125.3 kJ mol−1. The enthalpy (ΔH*), free energy (ΔG*) and entropy (ΔS*) of inactivation were found to be stable with increasing temperature. CONCLUSION: The mutant A. sojae PG could be suitable for the clarification (depectinization) of orange and grape juices and wine. © 2015 Society of Chemical Industry.Article Citation - WoS: 28Citation - Scopus: 38Bioconversion of Wheat Bran for Polygalacturonase Production by Aspergillus Sojae in Tray Type Solid-State Fermentation(Elsevier Ltd., 2016) Demir, Hande; Tarı, CananWheat bran was tested as the solid substrate for the tray-type solid-state fermentation (SSF) production of polygalacturonase (PG) enzyme by A. sojae mutant strain - a high-PG activity producer. PG production of A. sojae was found to reduce as the thickness of the substrate increase from 8 mm to 14 mm at 90% relative humidity. An interaction between the thickness of the bed and relative humidity of the environment was determined with the help of experimental design and statistical analysis tools. As a result, the PG activity could be enhanced by 31% as the process conditions optimized. Additionally, 11 mm thickness and 70% relative humidity were selected as the PG production favoring conditions with the maximum PG activity of 298 U/g substrate in tray type of SSF without the addition of any nutritive or inducing supplements into wheat bran. The kinetic study conducted in the trays revealed the presence of reduction in the water activity on the 4th day of the SSF process under stated conditions. The productivity of the process conducted under optimized conditions was 3.41 U/g substrate-1 h-1 for the 4th day of the SSF. © 2015 Elsevier Ltd.Article Citation - WoS: 13Citation - Scopus: 14Evaluation of Orange Peel, an Industrial Waste, for the Production of Aspergillus Sojae Polygalacturonase Considering Both Morphology and Rheology Effects(TUBITAK, 2014) Gögüş, Nihan; Hakgüder Taze, Bengi; Demir, Hande; Tarı, Canan; Ünlütürk, Sevcan; Lahore, Marcelo FernandezOrange peel is an agroindustrial waste rich in pectin and known to be an inducer for pectinase production. The use of this low-cost substrate for the production of an industrially important enzyme, polygalacturonase (PG), can be an alternative way to turn this waste into a value-added product, contributing to the reduction of environmental waste disposal problems. Enzyme productions by fungal microorganisms are affected by environmental and nutritional factors, demanding the determination of optimum conditions for maximum enzyme production with the desired fungal morphology and broth rheology. Therefore, complex and additional carbon sources were optimized with respect to PG production by Aspergillus sojae using statistical approaches. Effect of pH, another significant parameter affecting the rheology and morphology of the strain, was investigated in the serial bioreactor system using the optimized medium composition. Highest PG enzyme yield and productivity together with the maximum PG enzyme production (93.48 U/mL) were obtained under uncontrolled pH conditions. Under these conditions, morphologically, pellet sizes exhibited a normal distribution ranging between 0.5-1.0 mm and 1.0-1.5 mm, and rheological measurements revealed that fermentation broths showed non-Newtonian flow. The low pH trend observed during the course of the fermentation was another important positive outcome for industrial fermentations, prone to contamination problems.Article Citation - WoS: 48Citation - Scopus: 58Valorization of Wheat Bran for the Production of Polygalacturonase in Ssf of Aspergillus Sojae(Elsevier Ltd., 2014) Demir, Hande; Tarı, CananWheat bran, among various agro industrial by products, screened for the production of polygalacturonase (PG) in solid-state fermentation of Aspergillus sojae mutant strain, was found to be the most suitable substrate without the addition of any nutritive or inducing supplement. It was further characterized for its physicochemical composition and particle size distribution. The process conditions that favored the PG production using this substrate were determined as; 107 spore/g substrate inoculum concentration, 4 days of fermentation, 37°C of incubation temperature, 62% initial moisture content, water as the moistening agent, 100-250μm particle size of wheat bran, 3 times/day agitation and spore solution as the inoculum type which resulted into maximum PG activity of 535.4U/g substrate. Overall, this optimization process resulted in 7.3 and 3.9 fold of significant enhancement in the PG activity and productivity, respectively.Article Citation - WoS: 13Citation - Scopus: 16Dilute-Acid Hydrolysis of Apple, Orange, Apricot and Peach Pomaces as Potential Candidates for Bioethanol Production(American Scientific Publishers, 2013) Üçüncü, Can; Tarı, Canan; Demir, Hande; Büyükkileci, Ali Oğuz; Özen, BanuChemical composition of four selected fruit pomaces (agro-industrial wastes) was evaluated. The effect of temperature, time, acid concentration and solid:liquid (S:L) ratio on dilute-acid hydrolysis of selected pomaces were investigated using 24 factorial and central composite design and optimum hydrolysis conditions were determined. A preliminary study was initiated using apple hydrolysate and the fungus Tricoderma harzianum in order to explore and demonstrate their potential uses in bioethanol production. Chemical composition of pomaces was promising as fermentation media. The highest reducing sugar yield from the optimization step was 31%, 49%, 56% and 52% for apple, apricot, orange and peach pomaces, respectively under optimum hydrolysis conditions. Neither furfural nor hydroxmethylfurfural (HMF) were detected in hydrolysates. The highest bioethanol production (1.67 g/L) was obtained in 6 days in a non-static incubator using Tricoderma harzianum pregrown in minimal medium. It was demonstrated that selected pomaces holds potential for bioethanol production and can be eliminated without being potential waste problem to the environment, with economical return. Although, this work is an initial study in showing the potential of these pomaces and T. harzianum in bioethanol production, an extensive study on the optimization of fermentation parameters is recommended for further increase of bioethanol production. Copyright © 2013 American Scientific Publishers All rights reserved.Article Citation - WoS: 28Citation - Scopus: 32Optimization of the Process Parameters for the Utilization of Orange Peel To Produce Polygalacturonase by Solid-State Fermentation From an Aspergillus Sojae Mutant Strain(TUBITAK, 2012) Demir, Hande; Göğüş, Nihan; Tarı, Canan; Heerd, Doreen; Lahore, Marcelo FernandezThe effect of orange peel concentration, HCl concentration, incubation time and temperature, and inoculum size on the spore count and activity of polygalacturonase (PG) enzyme produced from Aspergillus sojae M3 by solidstate fermentation was screened using 2k factorial design. Orange peel and HCl concentrations and incubation time were significant factors affecting the responses. Optimum conditions favoring both PG and spore production from Aspergillus sojae M3 were determined as 2% orange peel and 50 mM HCl concentrations at 22 °C and 4.3 days of incubation. An overlay plot was constructed for use as a practical chart for production of high enzyme activity (>35.0 U/g substrate) and spore count (9.0 × 108 to 2.0 × 109 spore/mL) by superimposing the contours of PG activity and spore count responses. The accuracy and reliability of the constructed models on the responses was validated with the maximum calculated error rate between the predicted and actual activities at 14.1% and 22.4%, respectively. © TÜBİTAK.