| Abstract: | 為瞭解國產羊乳體細胞數與乳品質的關係，本研究自台中市西屯區之益健乳羊牧場（約400頭）及福隆鮮羊乳場（約200頭）共約600頭採取乳樣。自民國88年11月至90年10月每隔週自兩家乳羊場各採兩次總生羊乳作為樣品，並分析其體細胞數、脂肪率、乳糖含量、無脂固形分、乳固形分及各含氮化合物。結果發現，如將羊總乳體細胞數分為小於50、50-100、100-150、150-200及200萬/mL以上等五個區間時，呈現一常態自然分佈現象，其中以分佈在100-150萬/mL區間內之樣品數(36.67%)最多。收乳季節區分對總乳體細胞數高低影響並不顯著。就總乳成分而言，除無脂固形分與體細胞數關係不顯著外，乳糖於體細胞數大於200萬/mL最低，脂肪與乳固形分於150-200萬/mL最低，而蛋白質於大於200萬/mL最高，其中酪蛋白態氮（casein nitrogen；CNN）於小於100萬/mL最高，而可溶性蛋白態氮（soluble nitrogen；SN）與蛋白月示-蛋白月東（proteose-peptone；PP）於大於200萬/mL時呈現最高( P < 0.05 )。另外，隨體細胞數之增加，其血纖維蛋白溶酉每活性及凝乳所須時間亦有隨之增加之趨勢，但體細胞數小於200萬/mL者差異並不顯著，大於200萬/mL時則呈差異顯著(P<0.01)。此外，以不同體細胞數之生乳產製保久鮮乳，並於室溫貯藏一與三個月後發現，其沈澱量亦隨體細胞數之增加而有增加之趨勢。 綜合上述，當體細胞數升至200萬/mL以上時，血纖維蛋白溶酉每活性及對熱敏感而易生沈澱之可溶性氮、蛋白月示-蛋白月東量顯著增加，因此建議收購羊乳體細胞數在150萬/mL以內之生乳應可有效改善其加工品質。
The purpose of this study was to investigate the relationship between goat milk quality and somatic cell counts (SCC) in Taiwan. The milk samples were collected directly from Yi-Chang Goat Milk farm and Fu-Long Goat Milk farm from No. 1999 to Oct. 2001. The various samples were taken twice in 14 days and determined the contents of milk fat, protein, lactose, total solids and solids-not-fat by infrared milk analyzer. Kjeldahl method was also used to examine the contents of nitrogen compounds. In this study, we devided the SCC of goat milk into five levels, <50, 50-100, 100-150, 150-200 and >200?104 cells /mL, respectively. More than 36% of samples were in the group of 100-150?104 cells /mL. There was no significant difference for SCC between warm season (Mar.-Aug.) and cool season (Sep.-Feb.) milk. Among the milk composition, the relationship between solid- not-fat and SCC was no significant difference. Lactose content was lowest in SCC over 200?104 cells /mL, fat and total solid contents were lowest in SCC of 150-200?104 cells/mL, but protein content were highest in SCC over 200?104 cells /mL. Among nitrogen compounds, the casein nitrogen content was highest in SCC under 100?104 cells/mL, but soluble nitrogen and proteose-peptone contents were highest in SCC over 200?104 cells /mL( P < 0.05 ). Another, as SCC increased, the plasmin activity and the time of milk coagulation were also increase, but that was no significant different when SCC under 200?104 cells/mL, and when SCC over 200?104 cells/mL was significant difference (p<0.01). When produced the long-life fresh milk with various SCC content Raw milk, the sediments were increased as SCC increased when it storaged for 1 to 3 months. In sum, the plasmin activity and the contents of soluble nitrogen and proteose-peptone increased dramastically when SCC got up to > 200?104 cells /mL. Therefore, we suggested that the SCC under 150?104 cells /mL was better for processing of goat milk. |
