Mustafa Şengül

The effect of storage conditions (temperature, light, time) and variety on the glycoalkaloid content of potato tubers and sprouts

The effects of variety, tuber group, storage period and storage type on glycoalkaloid levels of potato tubers and sprouts were investigated. Normal, wounded and greened tubers and sprouts from potatoes of varieties Marfona and Granola were analysed for α-solanine, α-chaconine and total glycoalkaloid concentration by using HPLC. The potatoes were stored in normal store light, normal store dark, retail refrigerator light, and retail refrigerator dark. Analyses were carried out at the beginning, 3rd and 6th months for the potatoes, and at 6th month for the sprouts. The tubers had an α-solanine content ranging from 0.01 to 6.46 mg/kg FW, α-chaconine content from 0.35 to 28.12 mg/kg FW and total glycoalkaloid content from 0.66 to 32.76 mg/kg FW.

Effect of thermosonication on physicochemical, microbiological and sensorial characteristics of ayran during storage

The aim of the study was to determine whether thermosonication extends the shelf life of ayran, an acidic milk drink. The effect of thermosonication at different temperatures (60, 70 and 80 °C) and times (1, 3 and 5 min) on the physicochemical and microbiological characteristics, and sensorial properties of ayran during storage were investigated. According to the results, thermosonication applied at 60 °C decreased lower the bacteria counts, although the Streptococcus thermophilus and Lactobacillus delbrueckii subsp. bulgaricus counts decreased as the temperature and time increased. The yeast and mold levels in samples treated with thermosonication were <1 log CFU mL(-1) during storage period. The ayran samples had non-Newtonian behavior, and the consistency coefficients of the thermosonicated samples were significantly higher than that of the heat-treated samples. Regarding serum separation, the most effective thermosonication treatment was applied at 70 °C for 3 min. The sensory properties of the thermosonicated samples were better than the thermal-treated samples after storage.

Kivi İlaveli Dondurmaların Bazı Fizikokimyasal, Reolojik ve Duyusal Özelliklerinin Belirlenmesi

Bu calismada farkli oranlarda (%4, %8, %12, %16 ve %20) kivi meyvesi ilave edilerek uretilen dondurmalarin bazi fiziksel, kimyasal, reolojik ve duyusal ozellikleri arastirilmistir. Kivi oraninin artmasi ile dondurma orneklerinin kurumadde (%), kul ve pH degerlerinin azaldigi, ilk damlama ve tamamen erime zamanlari ile asitlik (%) degerlerinin yukseldigi belirlenmistir. Dondurmalarin C vitamini icerikleri ise kivi ilavesinden onemli derece etkilenmis (P<0.01) ve kivi oraninin artisina bagli olarak C vitamini icerigi de artmistir. Dondurma ornekleri reolojik acidan incelendiginde, kontrol orneginin kivam katsayisi kivi ilave edilen dondurma orneklerine gore daha dusuk bulunmustur. Tum dondurma ornekleri psodoplastik davranis sergilemistir. Duyusal acidan, %4 oraninda kivi ilave edilmis dondurma orneginin renk, sakizimsi yapi, tekstur, lezzet, agizda erime, erimeye dayaniklilik ve genel kabul edilebilirlik puanlarinin diger orneklere gore daha yuksek oldugu ortaya konulmustur. Arastirma sonucunda, dondurma uretiminde kivi kullaniminin dondurmanin C vitamini icerigi ve kivami uzerine olumlu bir etkiye sahip oldugu tespit edilmistir.

Changes in Some Quality Properties of Kefir during Storage and Inhibition Effect of Water Soluble Extracts on Angiotensin-I Converting Enzyme Purified by Human Plasma

Abstract Angiotensin converting enzyme (ACE)-inhibitory activity in water soluble extracts (WSEs) of kefir was investigated. Kefir was produced traditionally using kefir grains and stored at refrigerated temperature for 20 days. During storage period (on 1, 5, 10, 15 and 20 days) in vitro ACE-inhibitory activity in WSEs was determined. ACE was purified from human plasma to determine kinetic parameters. Purified ACE had a specific activity of 20.75 EU.mg−1, a yield of 16.6% with a factor of 22100. The inhibition effects of kefir on ACE increased at 15 storage days than other storage days. Some microbiological and physicochemical characteristics of kefir were also studied. Counts of presumptive LAB on M-17 and presumptive LAB on MRS in the kefir were about 108 CFU.ml−1 throughout the storage period. Yeast counts were lower than lactic acid bacteria counts and the average of the counts was approximately 106 log CFU.ml−1. Storage period had a significant effect (P < 0.05) on titratable acidity and pH values. On the contrary, it had no significant effect (P > 0.05) on viscosity and serum separation values of kefir.

Çiğ ve Pastörize Sütten Üretilen Kaşar Peynirlerinin Olgunlaşma Süresince Bazı Mikrobiyolojik Özelliklerinin Karşılaştırılması

Bu calismada, cig ve pastorize sutten Kasar peyniri uretilerek 90 gunluk olgunlasma periyodu boyunca peynirlerin bazi mikrobiyolojik ozellikleri arastirilmistir. Pastorize sutun (65 oC’de 30 dak.) kullanildigi peynir uretiminde %1.5 oraninda starter kultur (Streptococcus thermophilus ve Lactobacillus bulgaricus) kullanilmistir. Olgunlasma suresince peynirlerin (0, 30, 60 ve 90. gunler) bazi mikrobiyolojik ozellikleri ortaya konulmustur. Arastirma sonuclarina gore, starter kultur ilavesinin Laktokok, Laktobasil ve maya ve kuf sayilari uzerine etkisi istatistiki olarak onemli (P 0.05) bulunmustur. Diger taraftan olgunlasma suresince, peynirlerin Laktokok, Laktobasil, maya-kuf ve TAMB sayilarindaki degisim istatistiki olarak onemli (p