Kırmızı biberin (capsicum annuum l.) fonksiyonel ve mikrobiyal özellikleri üzerine modifiye atmosferde paketlemenin etkisi

06.03.2018 tarihli ve 30352 sayılı Resmi Gazetede yayımlanan “Yükseköğretim Kanunu İle Bazı Kanun Ve Kanun Hükmünde Kararnamelerde Değişiklik Yapılması Hakkında Kanun” ile 18.06.2018 tarihli “Lisansüstü Tezlerin Elektronik Ortamda Toplanması, Düzenlenmesi ve Erişime Açılmasına İlişkin Yönerge” gereğince tam metin erişime açılmıştır.Bu çalışmada kırmızı biberin (Capsicum annuum L.) fonksiyonel ve mikrobiyal özellikleri üzerine modifiye atmosfer paketlemenin etkisi araştırılmıştır. Ayrıca modifiye atmosfer paketlenen örneklerde etilen emicinin etkisi de bir diğer araştırma konusu olmuştur. 10oC sıcaklıkta, %95 bağıl nemde ve karanlıkta 3 hafta depolanan örneklerin haftalık analizleri yapılmıştır. Antioksidan özelliklerini incelemek için DPPH radikalini giderme aktivitesi, toplam fenolik madde içeriği, OH● yakalama aktivitesi, FRAP yöntemi, askorbik asit içeriği ve CUPRAC analizi spektrofotometrik olarak uygulanmıştır. Ayrıca örneklerin tiyol analizi HPLC cihazıyla saptanmıştır. Mikrobiyolojik analizlerde ise toplam mezofilik aerobik bakteri, maya-küf, anaerobik bakteri sayısı belirlenmiştir. 3 haftalık depolama süresi sonunda modifiye atmosfer paketlenen ve paketlenmeyen grupların üçünde de DPPH radikalini giderme aktivitesi, toplam fenolik madde, OH● yakalama aktivitesi, askorbik asit, CUPRAC ve tiyol içeriklerinde önemli derecede azalma meydana gelirken FRAP değerlerinde etilen emici bulunmayan grubta taze örneklere göre artış görülmüştür (P<0,05). Modifiye atmosfer paketlemenin etkisi incelendiğinde ise paketlenen örneklerin DPPH radikalini giderme aktivitesi, OH● yakalama aktivitesi, askorbik asit içeriği, FRAP ve CUPRAC değerleri paketlenmeyen kontrol grubuna göre yüksek bulunmuştur. GSH ve CYS değerlerinde ise tersi bir durum ortaya çıkmıştır. Toplam fenolik madde içeriğine bakıldığında paketlenen grup ile paketlenmeyen grup arasındaki fark istatistiki açıdan önemli bulunmamıştır (P<0,05). Modifiye atmosfer paketlenen gruplar arasında etilen emicinin etkisi incelendiğinde, 2. hafta sonunda etilen emici bulunan gruplarda toplam fenolik madde, FRAP ve askorbik asit değerleri etilen emici bulunmayan gruplara göre istatistiki açıdan yüksek olduğu belirlenmiştir. Ancak 3. hafta sonunda etilen emici bulunmayan grup daha yüksek DPPH radikalini giderme aktivitesi değerlerine sahip olurken toplam fenolik madde, OH● yakalama aktivitesi, FRAP ve CUPRAC değerlerinde 2 grup arasında istatistiki açıdan fark önemli bulunmamıştır (P<0,05). Üç hafta boyunca etilen emici bulunan gruplarda GSH içeriği istatistiki açıdan yüksek olurken, CYS içeriğinde etilen emici yalnızca 1. hafta sonunda etkili olmuştur. Yapılan mikrobiyolojik analizler sonucunda depolanan hiçbir örnekte toplam mezofilik aerobik bakteri, maya-küf ve anaerobik bakteriye rastlanmamıştır. Sonuç olarak bu çalışma göstermiştir ki modifiye atmosfer paketleme yapılan kırmızı biberlerin antioksidan özellikleri paketlenmeyen örneklere göre daha yüksektir. Paketlenen örnekler arasında etilen emicinin etkisi incelendiğinde ise 2. hafta sonuna kadar etilen emici kullanımının biberlerin fonksiyonel özelliklerini daha iyi koruduğu belirlenmiştir.In this study, effects of MAP on functional and microbial properties of red pepper (Capsicum annuum L.) were investigated. Moreover, effect of ethylene absorber on MAP samples was another research topic. Samples stored at 10oC with 95% relative humidity were analyzed weekly in 21 days. To investigate antioxidant properties of samples, DPPH scavenging activity, total phenolic contents, ,OH● scavenging activity, FRAP, ascorbic acid content and CUPRAC analyses were applied spectrophotometrically. In addition, thiol contents were determined by HPLC. Total mesophilic aerobic bacteria, yeast-mold, anaerobic bacteria numbers were detected with microbiological analyses. After 3 weeks storage time, while DPPH scavenging activity, total phenolic compounds, OH● scavenging activity, ascorbic acid and CUPRAC values were decreased in all groups, FRAP values in samples not include ethylene absorbers were increased according to fresh samples (P<0,05). DPPH scavenging activity, OH● scavenging activity, FRAP, ascorbic acid content and CUPRAC values were found higher in MAP samples than the control group. However, thiol contens in MAP group were lower than controls. According to total phenolic compounds, the difference between MAP and the control group was not significant (P<0,05). As a result of microbiological analyses, total mesophilic aerobic bacteria, yeast-mold and anaerobic bacteria was not found any of the samples. When the effect of ethylene absorber was examined on MAP samples after 2 weeks, it was seen that the groups with ethylene absorber had higher total phenolic compounds, FRAP, GSH and ascorbic acid values. On the other hand, while the groups without ethylene absorber had higher DPPH scavenging activity and CYS content, there was no significant difference according to OH● scavenging activity and CUPRAC values between these two groups in statistical analysis. As a result, this study indicates that the modify atmosphere packaging of red peppers have higher antioxidant property than the control group. In addition, using ethylene absorber protects the functional properties of red pepppers better than other group at the end of 2 weeks

Postharvest Application of Thiol Compounds Affects Surface Browning and Antioxidant Activity of Fresh-Cut Potatoes

The aim of this study was to compare the effects of sodium metabisulphite and the thiol compounds, glutathione (GSH), L-cysteine (CYS), and N-acetylcysteine (NAC), on the enzymatic browning, antioxidant activities, total phenolic, and ascorbic acid content of potatoes after 1, 24, and 48 hr. Three different concentrations (0.5%, 1.0%, and 2.0%) of each thiol compound were tested. While sulphite solution inhibited polyphenol oxidase as expected, NAC and CYS also decreased its activity. CYS-treated samples exhibited the highest residual thiol content, while the amount of residual thiol in GSH-treated samples was the lowest. The 2.0% NAC and 2.0% CYS solutions were the most effective at increasing antioxidant activity and ascorbic acid content; however, the results of total phenolic content assays were complicated. In summary, solutions containing 2.0% NAC, 1.0% CYS, and 2.0% CYS prevented enzymatic browning and increased the residual thiol content, ascorbic acid, and antioxidant activities of fresh-cut potatoes significantly, but GSH did not significantly inhibit browning. Practical applications: Fresh-cut potatoes are susceptible to enzymatic browning, which significantly reduces their commercial value. In literature, there have been several methods to protect the enzymatic browning of fruits and vegetables. Among these methods, thiols are good inhibitors of enzymatic browning. So, GSH, CYS, and NAC were used in this study. The outcomes of current work may help to inhibit polyphenol oxidase activity and increase the ascorbic acid content, residual thiol content, and antioxidant activity of fresh-cut potatoes. Both CYS and NAC may be useful alternatives to sulphite anti-browning agents, which may have adverse health effects

Thiols and Their Uses in the Food Industry

Yapılan çalışmalar gıdalara farklı amaçlar doğrultusunda eklenen sentetik katkı maddelerinin_x000D_ birçoğunun insan sağlığını olumsuz yönde etkilediğini ortaya koymaktadır. Bu sebeple,_x000D_ araştırmacılar hem sentetik katkı maddelerinin yerini alabilecek hem de çeşitli fonksiyonları ile_x000D_ sağlığı olumlu etkileyecek doğal katkı maddeleri üzerine yoğunlaşmıştır. Biyotiyoller, gıdalarda_x000D_ renk, tat ve aroma üzerinde etkileri bulunan aynı zamanda antioksidan ve koruyucu etkileriyle_x000D_ oksidatif hasarı engelleyerek kanser, Alzheimer, Parkinson, akciğer ve kalp hastalıklarının_x000D_ önlenmesinde çeşitli fonksiyonlara sahip olan bileşiklerdir. Bu derlemede, gıdaların tiyol içerikleri,_x000D_ fonksiyonları ve gıda sektöründe sentetik katkı maddelerinin yerine kullanım olanakları üzerine_x000D_ yapılmış çalışmalar bir araya getirilmiştir. _x000D_ _x000D_Studies have shown that many of the synthetic additives which are added to food for different_x000D_ purposes have negative impacts on human health. For this reason, researchers have focused on_x000D_ natural additives that can replace with synthetic ones and positively affect health through their_x000D_ various functions. Biothiols have effects on color, taste and aroma in foods. In addition, they possess_x000D_ various functions in the prevention of cancer, Alzheimer's, Parkinson's, lung and heart diseases by_x000D_ decreasing oxidative damage with their antioxidant and protective effects. In this review, the studies_x000D_ about thiol contents of food, their functions and the possibilities of using thiols in the food industry_x000D_ instead of synthetic additives have been brought together

Enrichment of cookies with glutathione by inactive yeast cells (Saccharomyces cerevisiae): Physicochemical and functional properties

Cookie is one of the favorite cereal products which could be formulated by using various ingredients for enrichment. The aim of this study was to determine the effects of the inactivate yeast cells addition to cookie formulation in terms of glutathione (GSH) content, antioxidant activities, physicochemical and sensorial properties. Also, the cookies were produced with GSH (pure, 98%) addition to compare the effects of inactive yeast GSH with pure GSH on revealed properties. According to results, The GSH contents and the antioxidant activities increased in dough and cookie samples with inactive yeast addition compared to control and pure GSH added dough and cookie samples. The increases in GSH contents and antioxidant activities were observed after baking in all samples. The pure GSH addition increased the moisture content, spread ratio and L* value while decreased the hardness and b* values of the cookies. The contrary results were obtained by inactive yeast addition in terms of the physicochemical properties where the protein content of the cookies increased with inactive yeast addition by approximately 25%. The loss of GSH content decreased while the antioxidant activities and nutritional value increased in cookies by inactivate yeast addition. (C) 2017 Elsevier Ltd. All rights reserved

Comparative study of functional properties of eight walnut (Juglans regia L.) genotypes

Eight walnut (Juglans regia L.) genotypes were assessed for the glutathione (GSH) and total phenolic contents (TPC), as well as their antioxidant capacities. The GSH contents were between 1.1 and 7.2 mg 100 g(-1). The TPC contents ranged from 33 to 50.3 mg GAE g(-1), while the ferric ion reducing antioxidant power (FRAP) values ranged from 156 to 302 mg FeSO4 g(-1). A strong correlation (r(2) = 0.8258) was determined between the FRAP values and the TPC. Cupric ion reducing antioxidant capacity (CUPRAC) values ranged from 13 to 35 mg trolox g(-1). The correlation between the CUPRAC values and the GSH contents was weak (r(2) = 0.2069). The walnut extracts (0.2 mg mL(-1) concentration) showed 16.2-40% DPPH (2,2-diphenyl-1-picrylhydrazyl) scavenging activity. A strong correlation between DPPH-TPC was determined (r(2)= 0.8538), and it was concluded that the TPC makes the most important contribution to the antioxidant capacity of the walnut. Additionally, the walnut may be appraised, in view of its nutritional value and health benefits, by considering the GSH content revealed in the current study

Comparative study of functional properties of eight walnut (Juglans regia L.) genotypes

Abstract Eight walnut (Juglans regia L.) genotypes were assessed for the glutathione (GSH) and total phenolic contents (TPC), as well as their antioxidant capacities. The GSH contents were between 1.1 and 7.2 mg 100 g-1. The TPC contents ranged from 33 to 50.3 mg GAE g-1, while the ferric ion reducing antioxidant power (FRAP) values ranged from 156 to 302 mg FeSO4 g-1. A strong correlation (r2=0.8258) was determined between the FRAP values and the TPC. Cupric ion reducing antioxidant capacity (CUPRAC) values ranged from 13 to 35 mg trolox g-1. The correlation between the CUPRAC values and the GSH contents was weak (r2=0.2069). The walnut extracts (0.2 mg mL-1 concentration) showed 16.2-40% DPPH (2,2-diphenyl-1-picrylhydrazyl) scavenging activity. A strong correlation between DPPH-TPC was determined (r2=0.8538), and it was concluded that the TPC makes the most important contribution to the antioxidant capacity of the walnut. Additionally, the walnut may be appraised, in view of its nutritional value and health benefits, by considering the GSH content revealed in the current study

Estimation of antioxidant activity of foods using artificial neural networks

The aim of this study was to demonstrate that artificial neural networks (ANN) is an economical and rapid method to estimate antioxidant activity of foods. Phenolic content of different food varieties (red pepper and grape seeds) was used as two input variables, and ferric ion reducing antioxidant power (FRAP) values were estimated as output. The number of total experimental data was 150 (70 % for train, 30 % for test). The developed ANN was able to reveal the relationship between phenolic compounds and antioxidant activity of food with the feed-forward model. The estimated FRAP values calculated by ANN correlated with experimental FRAP values with high correlation coefficients. In addition, error rate was found to be approximately 10 %, which corresponds to approximately 90 % of success. The relationship between antioxidant substances and antioxidant activity demonstrated that ANN can be used to determine the antioxidant properties of foods and results of this study showed that this was possible. By this way, it was demonstrated that ANN is a reliable software-based method to estimate antioxidant capacities of foods with savings of time, labour and experimental costs

Estimation of antioxidant activity of foods using artificial neural networks

The aim of this study was to demonstrate that artificial neural networks (ANN) is an economical and rapid method to estimate antioxidant activity of foods. Phenolic content of different food varieties (red pepper and grape seeds) was used as two input variables, and ferric ion reducing antioxidant power (FRAP) values were estimated as output. The number of total experimental data was 150 (70 % for train, 30 % for test). The developed ANN was able to reveal the relationship between phenolic compounds and antioxidant activity of food with the feed-forward model. The estimated FRAP values calculated by ANN correlated with experimental FRAP values with high correlation coefficients. In addition, error rate was found to be approximately 10 %, which corresponds to approximately 90 % of success. The relationship between antioxidant substances and antioxidant activity demonstrated that ANN can be used to determine the antioxidant properties of foods and results of this study showed that this was possible. By this way, it was demonstrated that ANN is a reliable software-based method to estimate antioxidant capacities of foods with savings of time, labour and experimental costs