Yenilebilir mantarın (Cordyceps militaris) potansiyel prebiyotik aktivitesinin ve süt fermantasyonu üzerine etkisinin belirlenmesi
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Date
2018-06-18
Authors
Kıyak, Berrak Delikanlı
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Publisher
Uludağ Üniversitesi
Abstract
Bu çalışmanın ilk aşamasında, Bifidobacterium bifidum, Bifidobacterium longum subsp. infantis ve Bifidobacterium animalis subsp. lactis suşlarının karbonhidrat içermeyen Tryptone Peptone Yeast Extract besi ortamına ilave edilen Cordyceps militaris mantar ekstraktını in vitro koşullarda fermente edebilme yetenekleri araştırılmıştır. Ayrıca iki kontrol grubu bulunmaktadır: hiç karbonhidrat içermeyen negatif kontrol ile %1 oranında glikoz ya da inülin içeren örnekler pozitif kontrol olarak değerlendirilmiştir. Mantar ekstraktı içeren bazal ortamda geliştirilen kültürlerden, prebiyotik fermantasyonun 0., 12., 24., 36. ve 48. saatlerinde alınan örneklerde pH, hücre yoğunluğu (OD), prebiyotik aktivite sayısı (PAS), gelişme oranı, kısa zincirli yağ asitlerinin (KZYA) miktarı, laktik asit değerlerinin toplam KZYA'ya oranı ve fenolik madde içeriği ile antioksidan kapasite belirlenmiştir. Çalışmanın ikinci aşamasında ise; Cordyceps militaris ekstraktının potansiyel prebiyotik kaynağı olarak kullanılabilirliğini araştırabilmek amacıyla mantar ekstraktı ile zenginleştirilen probiyotik yoğurt üretimi gerçekleştirilmiştir. Depolama süresinin 1., 7., 14. ve 28. günlerinde fiziko-kimyasal (pH, titrasyon asitliği, serum ayrılması, renk (L, a, b)), tekstürel ve görünüş (sıkılık, konsistens, iç yapışkanlık, viskozite indeksi) ile duyusal (kıvam (ağızla), kıvam (kaşıkla), koku, tat ve genel kabul edilebilirlik) özellikleri incelenmiştir. Elde edilen sonuçlara göre mantar ekstraktının Bifidobacterium türlerinin gelişmesini desteklediği, prebiyotik fermantasyon süresince pH değerlerinin azaldığı ve besi ortamındaki OD değerleri arttığı gözlenmiştir. En düşük pH ve en yüksek OD değerleri B. lactis varlığında tespit edilmiştir. Fermantasyon süresince üretilen KZYA'nin büyük oranda laktik ve asetik asit ile daha düşük miktarlarda propiyonik ve bütirik asidin oluştuğu belirlenirken, en yüksek KZYA değeri B. bifidum içeren besi ortamında saptanmıştır (p<0,01). Antioksidan aktivitenin yüksek olduğu örneklerde toplam fenolik maddenin de yüksek olduğu belirlenmiştir. Probiyotik yoğurt örneklerinin mantar ekstraktı ile zenginleştirilmesinin pH, titrasyon asitliği, serum ayrılması, renk değerleri ile tekstürel ve duyusal özellikler üzerine etkide bulunduğu saptanmıştır (p<0,01). Mantar ekstraktı ile probiyotik bakteri arasındaki etkileşim ve buna bağlı olarak artan asitliğin tekstürel özellikleri etkilediği belirlenmiştir. Ayrıca mantar ekstraktının tat açısından ağızda baskın bir mantar aroması ile birlikte boğazda acılık bıraktığı ve koku açısından ise probiyotik yoğurdun kendine has kokusunu baskıladığı tespit edilmiştir. Sonuç olarak, Cordyceps militaris mantar ekstraktının Bifidobacterium türlerinin gelişmesi/aktivitesi üzerine olumlu etki gösterdiği in vitro çalışmalar ve süt fermantasyonu üzerine etkisi de yoğurt modelinde denenerek prebiyotik potansiyele sahip bileşen olarak kullanılabileceği belirlenmiştir.
The first part of the present work was intended to assess the growth stimulation and fermentation capacity (digestibility) of Cordyceps militaris, added to non-carbonhydrate containing Tryptone Peptone Yeast Extract nutrient media, by Bifidobacterium bifidum, Bifidobacterium longum subsp. infantis, and Bifidobacterium animalis subsp. lactis under in vitro conditions. Moreover, two controls were used: a negative control containing basal medium without carbohydrate, and a positive control containing basal medium supplemented either with 1%glucose (w/v) or inulin (w/v). The samples were taken at the 0th, 12th, 24th, 36th, and 48th hours of prebiotic fermentation from cultures grown on basal media including mushroom extract to analyse the pH, optic density (OD), prebiotic activity score (PAS), growth rate, amount of short chain fatty acids (SCFA), ratio of lactic acid values over total short chain fatty acids (LA:SCFA), and total phenolic content and antioxidant activity. The next step of our study was the production of the probiotic yoghurt enriched with the mushroom extract and its evaluation to gain insight about the prebiotic potential of Cordyceps militaris. On the 1st, 7th, 14th and 28th days of storage period physico-chemical (such as pH, titritable acidity, syneresis, color (L, a, b)), textural and visual (such as firmness, consistency, cohesiveness, index of viscosity), and sensorial (such as consistency (in-mouth), consistency (with spoon), odor, taste and general acceptability) properties were investigated. The results obtained indicated that mushroom extract stimulated the growth of Bifidobacterium species. During prebiotic fermentation the OD values in nutrient media increased whereas pH values decreased. The lowest pH and highest OD values were observed with B. lactis. It was observed that SCFAs produced during fermentation were predominantly lactate and acetate with lower amounts of propionate and butyrate. The highest SCFA values were in the nutrient media with B. bifidum (p<0,01). Furthermore, antioxidant activity was positively correlated with the total phenolic content; the higher phenolic content the higher antioxidant activity. The enrichment of probiotic yoghurt with mushroom extract was influential on values of pH, titritable acidity, syneresis, color, and textural and sensorial attributes (p<0,01). The interaction between mushroom extract and probiotic culture, and hence increased acidity, had an impact on textural properties. In addition, in terms of taste the mushroom extract left a dominant aroma in-mouth and bitterness in throat, and in terms of odor it suppressed the characteristic flavor of prebiotic yoghurt. Consequently, the results suggested that Cordyceps militaris mushroom extract showed a positive stimuli on growth and activity of Bifidobacterium species in vitro, and it could be considered as potential prebiotic source as its impact had been evaluated on milk fermentation by a yoghurt model.
The first part of the present work was intended to assess the growth stimulation and fermentation capacity (digestibility) of Cordyceps militaris, added to non-carbonhydrate containing Tryptone Peptone Yeast Extract nutrient media, by Bifidobacterium bifidum, Bifidobacterium longum subsp. infantis, and Bifidobacterium animalis subsp. lactis under in vitro conditions. Moreover, two controls were used: a negative control containing basal medium without carbohydrate, and a positive control containing basal medium supplemented either with 1%glucose (w/v) or inulin (w/v). The samples were taken at the 0th, 12th, 24th, 36th, and 48th hours of prebiotic fermentation from cultures grown on basal media including mushroom extract to analyse the pH, optic density (OD), prebiotic activity score (PAS), growth rate, amount of short chain fatty acids (SCFA), ratio of lactic acid values over total short chain fatty acids (LA:SCFA), and total phenolic content and antioxidant activity. The next step of our study was the production of the probiotic yoghurt enriched with the mushroom extract and its evaluation to gain insight about the prebiotic potential of Cordyceps militaris. On the 1st, 7th, 14th and 28th days of storage period physico-chemical (such as pH, titritable acidity, syneresis, color (L, a, b)), textural and visual (such as firmness, consistency, cohesiveness, index of viscosity), and sensorial (such as consistency (in-mouth), consistency (with spoon), odor, taste and general acceptability) properties were investigated. The results obtained indicated that mushroom extract stimulated the growth of Bifidobacterium species. During prebiotic fermentation the OD values in nutrient media increased whereas pH values decreased. The lowest pH and highest OD values were observed with B. lactis. It was observed that SCFAs produced during fermentation were predominantly lactate and acetate with lower amounts of propionate and butyrate. The highest SCFA values were in the nutrient media with B. bifidum (p<0,01). Furthermore, antioxidant activity was positively correlated with the total phenolic content; the higher phenolic content the higher antioxidant activity. The enrichment of probiotic yoghurt with mushroom extract was influential on values of pH, titritable acidity, syneresis, color, and textural and sensorial attributes (p<0,01). The interaction between mushroom extract and probiotic culture, and hence increased acidity, had an impact on textural properties. In addition, in terms of taste the mushroom extract left a dominant aroma in-mouth and bitterness in throat, and in terms of odor it suppressed the characteristic flavor of prebiotic yoghurt. Consequently, the results suggested that Cordyceps militaris mushroom extract showed a positive stimuli on growth and activity of Bifidobacterium species in vitro, and it could be considered as potential prebiotic source as its impact had been evaluated on milk fermentation by a yoghurt model.
Description
Keywords
Cordyceps militaris mantar ekstratı, Prebiyotik, Bifidobacterium, Cordyceps militaris mushroom extract, Prebiotic
Citation
Kıyak, B. D. (2018). Yenilebilir mantarın (Cordyceps militaris) potansiyel prebiyotik aktivitesinin ve süt fermantasyonu üzerine etkisinin belirlenmesi. Yayınlanmamış doktora tezi. Uludağ Üniversitesi Fen Bilimleri Enstitüsü.