| Abstract: | 羊乳體細胞數與乳品質關係之研究無論在國內外均為少見。為了解羊乳體細胞數與乳汁品質的關係，本研究自台中市西屯區之益健乳羊牧場及福隆鮮羊乳場（共飼乳羊約600頭）採取乳樣。自民國88年5月至89年4月每隔2週自兩家乳羊場各採兩次總生羊乳作為樣品。分析測定體細胞數、脂肪率、乳糖含量、無脂固形分、乳固形分及含氮化合物。 結果發現，如將羊乳體細胞數分為小於50、50-100、100-150、150-200及200 萬/mL以上時，呈現一常態自然分布現象，其中以分布在100-150萬/mL區間內之樣品數最多。收乳季節區分對羊乳體細胞數高低影響並不顯著 ( P > 0.05 )。就總乳成份而言，除無脂固形分與羊乳體細胞數關係不顯著( P > 0.05 )外，乳糖於大於200萬/mL最低，脂肪與乳固形分於150-200萬/mL最低，而蛋白質與總氮量於大於200萬/mL最高，其中酪蛋白態氮於小於100萬/mL最高，而可溶性蛋白態氮與蛋白?-蛋白?於大於200萬/mL時呈現最高( P < 0.05 )。 綜合上述，如針對羊乳之熱加工而言，當體細胞數升至200萬/mL以上時，對熱敏感而易生沉澱與褐化之可溶性氮、蛋白■-蛋白■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。(關鍵語：羊乳組成份、體細胞數、含氮化合物)
The purpose of this study was to investigate the relationship between goat''s 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 May 1999 to April 2000. The various samples were taken twice in a week and determined the contents of milk fat, protein, lactose, total solids and solids-non-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''s milk into five levels, <50, 50-100, 100-150, 150-200 and >200?10,000 cells /mL, respectively. More than 36% of samples was in the group of 100-150?10,000 cells /mL. There was no significant difference (P > 0.05) for SCC between warm season (Mar.-Aug.) and cool season (Sep.-Feb.) milk. Among the milk composition, the relationship between solid- non-fat and SCC was no significant difference (P > 0.05). Lactose content was lowest in SCC of 200?10,000 cells /mL, fat and total solid contents were lowest in SCC of 150-200?10,000 cells/mL, but protein and total nitrogen contents were highest in SCC of 200?104 cells /mL. Among nitrogen compounds, the casein nitrogen content was highest in SCC of 100?104 cells/mL, but soluble nitrogen and protesose-peptone contents were highest in SCC of >200?10,000 cells /mL( P < 0.05 ). In sum, the contents of soluble nitrogen and protesose- peptone increased dramastically when SCC got up to > 200?10,000 cells /mL. Therefore, we suggested that the SCC under 150?10,000 cells /mL was better for processing of goat milk.(Keyword: goat''s milk composition, somatic cell counts, nitrogen compounds) |
