Ekşi hamur tozu eldesi ve ekmek üretiminde kullanılabilme olanakları
Production of sourdough powder and its potential use in bread production
Yazar: FATMA BURCU AKGÜN
Danışman: YRD. DOÇ. DR. YUSUF YILMAZ
Pamukkale Üniversitesi / Fen Bilimleri Enstitüsü / Gıda Mühendisliği Ana Bilim Dalı
Derece: Yüksek Lisans, 2007
Konu: Gıda Mühendisliği = Food Engineering
Dizin: Ekmek = Bread

Özet:
Bu çalmann amac, frnclk sektöründe üretimi hzlandrmak ve günlük ekmekkapasitesini arttrmak amacyla yaygn olarak kullanlan eki hamura alternatif olarakeki hamur tozunun üretilmesi ve ekmek üretiminde kullanlabilirliininaratrlmasdr. Bu amaçla un üzerinden %1 S.cerevisiae, %1 L.brevis ve her ikimikroorganizmadan %1'er orannda kullanlarak hamurlar hazrlanm, fermantasyonyaplmtr. Elde edilen eki hamurlar kurutulup öütülmek suretiyle eki hamur tozlarelde edilmitir. Elde edilen tozlar, una %0, %2, %4 ve %6 oranlarnda ikame edilerekekmek üretiminde kullanlabilirlii test edilmitir.Elde edilen sonuçlara göre, maya ve laktik starter kullanm, hamur ve ekmeközelliklerine, pH ve asitlik geliimine etkide bulunmutur. En düük pH 3.86 ve enyüksek toplam asitlik % 1.71 olarak L.brevis starter kültürlü örnekte ölçülmütür. Ekihamurlardan üretilen tozlarnda ise benzer sonuçlar bulunmu, en düük pH ve enyüksek toplam asitlik L.brevis'li örnektedir.Ekmek yapmnda eki hamur tozu ikamesi ya gluten, gluten indeksi,sedimantasyon ve gecikmeli sedimantasyon deerlerini düürmütür. Protein deerinietkilemezken, kül miktarn arttrmtr. Eki hamur tozunun unun su absorbsiyonunuve hamurun gelime süresini etkilemedii hamur stabilitesini ve yourma toleransnazaltt görülmütür. Hamurlarn yumuama dereceleri ise eki hamur tozu ikameoran arttkça art göstermitir. Eki hamur tozlu ekmek hamurlarnda hamurmukavemeti ve maksimum direnç etkilenmemi, uzayabilirlik ve enerji deerlerindedüme görülmütür.Eki hamur tozu ikame orannn yourma sonras ve son fermantasyon sonrashamur pH'larn etkiledii görülmü, ikame oran arttkça yourma sonras pH genelolarak düerken, ikame oran %6'ya çktnda ise pH sadece EHT(SL) örnei içinyükselmitir. )kame oran %2'ye çkarldnda fermantasyon sonras pH EHT(SC)örnei için hemen hemen deimezken dier iki örnek için hzl bir biçimde dümütür.)kame oran %4 olduunda ise pH'larda azalma devam etmi, %6 ikame oran için iseyine EHT(SC) örneinde önemli bir azalma görülmemitir.Eki hamur tozu ikamesi ile spesifik hacim deeri artm, en yüksek spesifik hacimEHT(SL) örneinde ve %6 ikameli ekmekte ölçülmütür. Eki hamur tozu ikamesininekmekte kabuk ve iç renk L, a, b deerlerini etkiledii görülmü, renk intensitesinisarya doru yöneltmitir. Duyusal deerlendirmede kontrol ekmei, %6 EHT (SC) veEHT (SL) ikame oranl ekmek ile %2 ve %4 EHT (LB) ikame oranl ekmeklerkullanlm, ekmekler arasnda fark hissedilememitir (p>0.05).Anahtar Kelimeler: Ekmek, Eki hamur, Eki Hamur Tozu

Abstract:
The aims of this study are to produce sourdough powder and to evaluate potentialuse of sourdough powder in bread making industry, which is alternative to sourdoughthat has been used to speed up the bread production and to increase the daily breadproduction capacity of bakeries. For this purpose, sourdough samples with 1%S.cerevisiae, 1% L.brevis or an equal mixture of these two microorganisms based onflour in the formulations were prepared and fermented. By drying and grindingsourdough samples produced, sourdough powder samples were obtained. Potential useof sourdough powder in bread production was tested by substituting flour informulations with 0%, 2%, 4% or 6%.Results indicated that the use of yeast and lactic starter culture had an effect onvarious properties of dough and bread sample, pH and acid production. The lowest pHof 3.86 and the highest total titratable acidity of 1.71% was obtained with the starterculture of L.brevis. Sourdough powder samples with this starter culture also showedsimilar properties with the lowest pH and the highest total titratable acidity.The substitution of flour with sourdough powder in breadmaking reduced wetgluten, gluten index, and sedimentation and delayed sedimentation values. Whilesubstitution increased the ash content of breads, it showed no effect on protein content.Addition of sourdough powder to flour had no effect on the water absorption ability offlour and dough recovery period while reducing both dough stability and kneadingtolerance. Softening degrees of dough samples raised with the increased substitutionrate with sourdough powder. Dough and maximum dough resistances were not affectedin bread dough samples prepared with sourdough powder while extensibility andenergy values reduced.Sourdough powder substitution had an effect on the post kneading and finalfermentation pH values of dough samples, and overall pH values reduced by theincrement in substitution ratio while pH of EHT(SL) sample increased with increasingthe ratio to 6%. When the substitution ratio increased to 2%, post fermentation pH ofEHT(SC) sample remained almost unchanged, but reduced rapidly for other twosamples. At the substitution ratio of 4%, pH continued to reduce, at 6%, pHsignificantly reduced for EHT(SC) samples.Sourdough powder substitution increased specific volumes of dough and breadsamples, and the highest specific volumes were observed with EHT(SL) dough sampleand bread samples with 6% substitution rate. Sourdough substitution significantlyaffected bread crust and interior color values of Hunter L, a and b, increasing the colorintensity towards yellow color space. In sensory evaluation of bread samples, controlbread, 6% EHT(SC) and EHT(SL) and 2% and 4% EHT(LB) substituted bread sampleswere used, and differences among the bread samples were insignificant (p>0.05).Keywords: Bread, Sourdough, Sourdough powder