Shelf-life extension of traditional licorice root “sherbet” with a novel pulsed electric field processing

Pulsed electric field (PEF) processing of licorice root “sherbet” (LRS) by various electric field strengths (7.00, 15.50, and 24.10 kV/cm), treatment times (108, 432, and 756 µsec), and processing temperatures (6, 18, and 30°C) according to the Box–Behnken design were performed. The samples were analyzed for pH, titratable acidity, conductivity, turbidity, total reducing sugar, color (L*, a*, and b*), hue, chroma, total color difference, color intensity, color tone (yellow, red, and blue color tones), total antioxidant capacity, total phenolic substance content, and sensory properties. Results revealed that PEF processing did not adversely affect most of the physical, chemical, and sensory properties of LRS, with a maximum of 2.48, 4.04, 1.78, and 1.20 log reductions on the initial total mesophilic aerobic bacteria, total mold and yeast, Bacillus circulans, and Candida tropicalis. The response variable modeled for the PEF was found to be conductivity, with the optimum processing conditions of 6.90 kV/cm, 756.00 µs, and 7.48°C. After that, the samples were stored at 4°C and 22°C for shelf-life studies. Control samples at 4°C and 22°C were spoiled on the fifth and second days, whereas PEF-treated samples stored at 4°C began to deteriorate after the 40th day and the samples stored at 22°C after the 30th day, respectively. It was revealed that PEF is a suitable process to extend the shelf-life of licorice “sherbet” with preservation of physicochemical and sensory properties

Fındık kabuğundan mikrobiyal alkali pektinaz üretimi.

Utilization of cheap and abundant materials for enzyme production is one of the strategies that can reduce the product costs. Besides, use of renewable agro-food industrial wastes as a raw material provides not only low cost and sustainable value added products but also is a solution to waste disposal problem.In this study, fermentation medium composition and conditions for maximal production of pectinase enzyme from Bacillus subtilis in submerged fermentation were investigated. The potential use of crude enzyme for clarification of carrot juice was also evaluated. In order to enhance utilization of the hazelnut shells as carbon source in pectinase production, various pretreatment methods including dilute acid, alkaline, and ozone pretreatments were tested prior to enzymatic hydrolysis step.After conversion of hazelnut shells to fermentable sugars, the “Plackett-Burman”(PB) design was used for screening of the eight factors; pH, fermentation time,temperature, inoculum volume (%v/v) and of pectin, yeast extract (YE),magnesium sulphate [MgSO4], and dipotassium hydrogen phosphate [K2HPO4]. Five variables (pH, time, temperature, yeast extract concentration and K2HPO4), which were determined to be significant by PB design, were further optimized using Box-Behnken response surface method to maximize the PG activity.The produced crude enzyme was tested in clarification of carrot juice, highly nutritious and worldwide consumed food material, afterwards. The carrot juice was treated with different concentration of crude pectinase (0.1-0.5%), pH (4-7), and time (2-6 h) for clarification.Among the pretreatment methods tested, the dilute acid pretreatment (3.42(w/w)%acid, 31.7 min, 130 oC) was chosen the best with higher sugar conversion (62.8% saccharification yield) than sodium hydroxide and ozone pretreatment methods.The pectinase optimization results indicated that a maximal PG activity of 5.60 U/mL was achieved at pH 7.0, 72 h, and 30 oC using 0.5% (w/v) of yeast extract and 0.02% (w/v) of K2HPO4. The results of clarification revealed that 100% clarity was achieved at 0.5% (w/v)enzyme load, 7.0 pH, and 6 h of clarification yield (%) with commercial enzyme reached only 78.18±3.14 %.This study also proved that crude enzyme was equally effective as the purified commercial enzyme.Ph.D. - Doctoral Progra

Improvement of Fermentable Sugar Extraction from Hazelnut Shells through Microwave Assisted Dilute Acid Pretreatment

The most effective method for producing fermentable sugars (FSs) from biomass is thermochemical pretreatment assisted by enzymatic hydrolysis. However, the enzymatic hydrolysis-assisted thermochemical pretreatment method is limited by the formation of fermentation inhibitors, and it is time-consuming. There is growing interest in using a microwave (MW) pretreatment due to its uniform and rapid heating. This study aimed to determine, perform data-driven modeling, and optimize the effect of MW combined with dilute acid pretreatment (MW-DA) on the production of FSs from hazelnut shells. An artificial neural networks (ANNs) model based on Box-Behnken Design (BBD) was the best model described for fermentable sugar extraction (FSE). Optimization via BBD-based ANNs model was carried out for an acid concentration of 0.5 to 2% (w/w), a pretreatment time of 5 to 25 min, a pressure of 5 to 15 bar, and a temperature of 120 to 160 °C. The optimized FSE was estimated at 374 mg/g (81.4% conversion efficiency), with a severity factor of 3.61 under 1.58% H2SO4 for 13 min at 160 °C and 8.5 bar. Using the MW-DA pretreatment process lowered the costs significantly due to the decreases in acid concentration and pretreatment time

Gıda Endüstrisi Atıklarından Alkali Pektinaz Üretimi Ve Modellenmesi

KAPSAM: Fındık atıklarından alkali pektinaz enzimi üretmek, enzim aktivite değişimini modellemek projede ulaşılmak istenen temel amaçtır.Bu proje ile hazırda kullanılan mısır, şeker pancarı, buğday kepeği, portakal kabukları vb. atıklara ilave olarak yeni bir hammadde kazandırılacak; dolayısıyla tarım ekonomisine canlılık kazandırmasının yanı sıra çevre sağlığına da olumlu etkilerinin olacağı düşünülmektedir. YÖNTEM/GEREKÇE: Projenin birinci aşamasında hammadde içerik analizi yapılacaktır. Öğütülen hammaddelerin nem, kül, yağ analizleri ve lignin analizleri ASTM standard test metodları kullanılarak yapılacaktır. Lignin içeriği asitte çözünebilen çözünemeyen lignin (Klason lignin) cinsinden ifade edilecektir. Projenin ikinci aşamasında lignin uzaklaştırılması sonucu etkili hidroliz yapılması hedeflenmektedir. Bu aşama, asit ve bazik hidroliz, toksik bileşenlerin çöktürülmesi ve bazı inhibitörlerin farklı pH değerlerinde iyonizasyonunu içermektedir. Asidik ve bazik hidrolizi incelemek için farklı asit konsantrasyonları, sıcaklık ve süreler denenecektir. Asit ve baz hidrolizi ile hemiselüloz monomer şekerlerine (arabinoz, galaktoz, mannoz ve ksiloz), selüloz da glukoza etkin bir şekilde dönüşebilmektedir. Selüloz ve hemiselüloz içerikleri HPLC ile analiz edilecektir. Önerilen projenin üçüncü aşamasında, öncelikle mikroorganizmanın aktivasyonu gerçekleştirilecek ve pektinaz enzim aktivitesi saptanacaktır. Mikroorganizma, 250 ml'lik erlenler içinde 50 ml maya ekstrakt pektin (YEP) ve fındık kabuğu veya küspesi ortamına eklenecek ve 37°C ‘de 200 rpm çalkalamalı inkübatörde 24 saat tutulacaktır. Bakteri hücrelerinin santrifüj ile çökelmesi sağlandıktan sonra sıvı kısmı alınarak pektinaz aktivitesi ölçülecektir. Bakteri biyokütlesi 600 nm'de spektrofotometre ile ölçülecektir. Kültür, 7000g'de 4°C'de ve 10 dk süreyle santrifüj edilecektir. Hücresiz supernatant aşağıda açıklanacak olan pektinaz aktivitesi için analiz edilecektir. YEP ortam bileşimi; pH 7.2'de 10.0g/l maya ekstraktı, 2.5g/l pectin içermektedir. Exo- poligalakturonaz enzim aktivitesi kalorimetrik yöntemle ölçülecektir. Exo-poligalakturonaz aktivitesini belirlemek için 0.2 mg/ml derişimindeki serbest pektinaz'ın 50 μl'si 250 μl % 1'lik pektin çözeltisi ile 50°C de 10 dk etkinleştirilecektir. Reaksiyonu durdurmak için ortama 300 μl dinitrosalisilik asit (DNSA) reaktifi eklenerek 530 nm'de absorbans değerinde ölçüm yapılacaktır. Çalışmanın son aşamasında ise, asit ve baz derişimi, sıcaklık ve hidroliz süresi optimize edilecektir. Deney planı Yanıt Yüzey Yöntemi kullanılarak hazırlanacaktır ve analiz sonucu şeker eldesi için en ideal koşullar saptanacaktır. BEKLENEN SONUÇ: 1)Yüksek şeker verimi (%80-90) ve 2)Minimum literatüre yakın enzim aktivite değerleri

Hydrolysis of Hazelnut Shells as a Carbon Source for Bioprocessing Applications and Fermentation

Hazelnut shells are generated in large amounts from hazelnut processing. Currently, it is used as fuel. However, reuse in bioprocessing can release remarkable content of sugars, which can be used for production of additives such as enzymes widely used in the food industry. Thus, the present study was undertaken to determine the effect of single and combined chemical and enzymatic hydrolysis on the production of fermentable sugars from hazelnut shells. Batch hydrolysis was carried out under various conditions to select optimal conditions. The results revealed that an optimal sugar concentration of about 19.2 g/l was achieved after 3.42% (w/w) dilute acid pretreatment conducted at 130 degrees C for 31.7 min and enzymatic load of 200 U/g for 24 h. The overall sugar yield was calculated as 72.4% (g reducing sugar/g total carbohydrate). Therefore, hazelnut shells can be considered a suitable feedstock to compete with synthetic sugars used in fermentations

Optimising clarification of carrot juice by bacterial crude pectinase

This study was undertaken to search for potential use of crude bacterial pectinase enzyme produced from Bacillus subtilis grown on hazelnut shell hydrolysate in clarification of carrot juice and to optimize the enzyme load, pH and time using the Box-Behnken response surface methodology (RSM). The carrot juice was treated with the crude pectinase enzyme (5.60 U mL(-1)) at different concentrations (0.1-0.5%), pH (4-7), and time (2-6 h). The obtained enzyme was also compared with commercial fungal pectinase at identical conditions. RSM provided optimal clarification conditions of 0.5% (w/v) enzyme load, 7.0 pH, and 6 h of time estimating 100% clarity, whose experimental counterpart was 94.47 +/- 0.01%. High values of coefficient of determination (R-2 = 0.9631), predicted R-2 (0.8989) and insignificant lack-of-fit (0.12) also showed that the model was successful in predicting % clarity for various combinations. This study also indicated that crude bacterial pectinase providing about 95% clarity is superior to commercial fungal pectinase, which gave 78% clarity under tested conditions, in terms of clarification ability for carrot juice