PASTÖRİZE KEÇİ SÜTÜNÜN DONDURULMASI VE DONDURARAK DEPOLAMASI SIRASINDA MEYDANA GELEN DEĞİŞMELER

Öz

Bu araştırmada, tam yağlı keçi sütünün pastörize edilip dondurulması esnasında ve dondurulan sütlerin12 aylık depolama süresi boyunca sütte meydana gelen değişmelerin belirlenmesine çalışılmıştır. Buamaçla, tam yağlı keçi sütü örnekleri süzüldükten sonra 65 °C’de 30 dakika pastörize edilerek farklıhacimdeki ambalajlara aktarılmış ve iki farklı sıcaklık derecesinde (-15 ve -35 °C) dondurulmuştur.Dondurulan sütler yine iki farklı depolama sıcaklığında (-18 ile -28 °C) bir yıl süre depolanmışlardır.Depolama süresince keçi sütlerinin toplam mezofilik aerobik bakteri sayısı, koliform bakteri sayısı, pH,titrasyon asitliği, viskozite, sedimantasyon, asitlik derecesi, oksidasyon, renk ve duyusal özellikleriincelenmiştir. Araştırmadan elde edilen sonuçlarına göre; keçi sütü örneklerinde koliform bakteri sayısındaazalma belirlenirken toplam mezofilik aerobik bakteri sayısında değişim gözlenmemiştir. Titrasyon asitliğimiktarlarında önemli değişme olmamış; pH, sedimentasyon, oksidasyon ve ADV değerlerinde önemliartışlar saptanmıştır. Dondurma ve depolama esnasında renk değerlerinde azalmalar tespit edilmiştir.Keçi sütlerinin koku, renk ve görünüş değerleri depolama boyunca değişmemiş, ikinci aydan sonra vizkozite değerlerinde artışla (p<0.05) hafif partiküllü yapı belirlenmiştir. Genel olarak değerlendirildiğindeproje çıktıları, pastörize keçi sütünü dondurarak saklamak suretiyle, kalitesinde hissedilir bir değişimolmadan raf ömrünün uzatılabileceğini de göstermiştir

Anahtar Kelimeler

• Keçi sütü, pastörize keçi sütü, dondurulmuş pastörize keçi sütü

THE CHANGES IN PASTEURIZED GOAT MILK DURING FREEZING AND THE FROZEN STORAGE

Öz

In this research, it was aimed to determine some properties of the pasteurized whole fat goat milk afterfreezing and the frozen storage for twelve months. For this purpose, the goat milk samples were filteredand pasteurized at 65 °C for 30 min, and transferred into two different packages, then frozen at -15 and-35 °C. The packages were stored at -18 and -28°C for one year. During storage period goat milk sampleswere investigated in terms of their microbiological (total aerobic mesophilic bacteria and coliformbacteria), chemical and biochemical properties (pH, titration acidity %, viscosity, sedimentation, aciddegree value, oxidation and colour) and sensory characteristics. According to the results obtained, whilethe effect of storage time on the counts of coliform bacteria were found to be significant, there were nodifference at total aerobic mesophilic bacteria count. At the same time, colour values were observed tobe significantly reduced during freezing and storage period. During the storage time; odour, colourand appeareance of goat milk samples were not changed, after the second month, the mild particlestructure was determined with increasing in viscosity values (P <0.05). An overall evaluation the obtainedresults showed that the freezing and keeping in the frozen storage of pasteurized goat prolonged theshelf life of pasteurized milk without any important change in the quality

Anahtar Kelimeler

• Goat milk, pasteurized goat milk, pasteurised-frozen goat milk

Kaynakça

1. Businco L, Bellantij C. 1993. Food Allergy in Chilghood, Hypersensivity to Cow’s Milk Allergens, Clin Exp Allergy, 23:481-483.
2. Park YW. 1994. Hypo-allergenic and therapeutic significance of goat milk. Small Ruminant Res.,14:151-159.
3. Haenlein GWF. 2004. Goatmilk in human nutrition. Small Ruminant Res. 51:155-163.
4. Kaiser C. 1990. Studies on the preparation of pure cow's milk proteins for immunologic differential diagnosis nutrivier allergies. Dissertation, İnst, Physiol, Und Biochem, Nutr, Bundesanstalt fuer Milchforschung, Universitaet Kiel, Kiel, Germany, 153p.
5. Guo MR, Dixon PH, Park YW, Gilmore JA, Kindstedt PS. 2001. Seasonal Changes in the Chemical Composition of Commingled Goat Milk. J Dairy Sci. 84(E, Suppl):79-83.
6. Babcock CJ, Roerig RN, Stabile JN, Dunlap WA, Randall R, 1947a. Frozen Homogenized Milk, II, Effect of Freezing and Storage Temperatures on the Chemical and Bacteriological Properties of Homogenized Milk. J Dairy Sci.30(1):49-54.
7. Babcock CJ, Stabile JN, Randall, R, Windham ES. 1947b. Frozen Homogenized Milk, III, Stability of Milk Solids Distribution in Frozen Homogenized Milk J Dairy SciVol, 30 (9): 733-736.
8. Babcock CJ, Stabile JN, Windham E, Evans LB, Randall R. 1948a. Frozen Homogenized Milk, IV, Keeping Quality of Frozen Homogenized Milk after Thawing. J Dairy Sci. 31: 805-810.

9. Babcock CJ, Stabile JN, Windham E, Evans LB, Randall R. 1948b. Frozen Homogenized Milk, V, Effect of Age Before Freezing on the Keeping Quality of Frozen Homogenized Milk. J Dairy Sci. 31(9): 811-815.
10. Babcock CJ, Windham E, Randall R. 1950. Homogenized Milk VII, Effect of Agitation during Freezing on the Keeping Quality of Frozen Homogenized Milk. J Dairy Sci. 32 (9): 812-816.
11. Weese SJ, Thayne WY, Butcher DF. 1973. Effect of Freezing Rare and Thawing Rate on Milk Properties. J Dairy Sci. 56 (2):168-170.
12. Katsiari MS, Voutsinas LP, Kondyli E. 2002. Manufacture of yoghurt from stored frozen sheep’s milk. Food Chemistry. 77(4):413-420.
13. Samuelson, EG, Thomas KE, Borgstrom G, Hjalmdahl, M. 1957. The manufacture and storage of frozen milkand cream, J Dairy Sci. 19:875.
14. Winder WC. 1962. Physical-Chemical Stability of Frozen Whole and Concentrated Milks. J Dairy Sci. 45 (8): 1024-1027.
15. Kurt A, Çakmakçı S, Çağlar A. 1996. Süt ve Mamülleri Muayene ve Analiz Metotlari Rehberi, A.Ü. Ziraat Fak. Yay. No:18, Erzurum, 238s.
16. Miller GL. 1959. Use of Dinitrosalicylic Acid Reagent for Determination of Reducing Sugar. Anal. Chem. 1959. 31(3):426-428.
17. Antifantakis E, Kehagias C, Kotouza I, Kalatzopoulos G. 1980. Frozen stability of sheeps milk under various conditions. Milchwissenschaft. 35:80-82
18. Case RA, Bradley RL, Williams RR. 1985. Che- mical and Physical Methods, Standard Methods for the Examination of Dairy Products. In: G,H, Richardson (Editor) APHA, Washingthon, D.C. 327-329.
19. Messer JW, Behney HM, Leudecke LO. 1985. Microbiological count methods, Standart Methods For The Examination of Dairy Products. (Editor: GH Richardson), 15th edt, American Public Health Association. Washington D.C. p, 133-141, 20. Metin M, 1977, Süt ve Mamüllerinde Kalite Kontrolü. Ankara Ticaret Borsası Yayınları No:1, Ankara.
20. Devore J, Peck R. 1993. Statistics-the exploration and analysis of data. Duxpury Press, an Imprint of Wadsworth Publishing Company, Belmont, California.
21. Zhang RH, Mustafa AF, Ng-Kwai-Hang KF, Zhao X. 2006.Effects of freezing on composition and fatty acid profiles of sheep milk and cheese. Small Ruminant Res, 64(3), 203-210.
22. Doan FJ, Warren FG. 1947. Observations on the Instability of the Protein Phase of Frozen Concentrated Milk. J Dairy Sci. 30 (11):837-848.
23. Webb BH, Hall SA. 1935. Some Physical Effects of Freezing upon Milk and Cream. J Dairy Sci. 18: 275.
24. Bell RW, Mucha TJ. 1951. Means of preventing an oxidized flavor in milk. J Dairy Sci.34: 432-437. 26. Bell RW. 1939.Effects of the Cold Storage Temperature, Heat Treatment, and Homogenization Pressure on the Properties of Frozen Condensed Milk. J Dairy Sci. 22(2): 89-100.
25. Van Den Berg, L. 1961. Changes in pH of Milk During Freezing and Frozen Storage, J Dairy Sci, 44 (1):26-31.
26. Wendorff WL, Rauschenberger SL. 2001. Effect of Freezing on Milk Quality, Proceedings of the 7th great lakes Dairy sheep symposium November 1-3, 2001 EAU Claire Wisconsin.
27. Ünlütürk A, Turantaş F. 1999. Gıda Mikrobiyolojisi. Mengi Tan Basımevi. İzmir, Türkiye 598s.
28. Winder WC. 1962. Physical-Chemical Stability of Frozen Whole and Concentrated Milks, J Dairy Sci, 45 (8): 1024-1027.
29. Doan FJ, Baldwin FB. 1936. Observations on the Freezing of Milk and Cream, II, The Destruction of the Fat Emulsion in Frozen Cream. J Dairy Sci, 19: 225.