醋是(shi)酸性(xing)(xing)物質，卻(que)是(shi)堿性(xing)(xing)食(shi)(shi)品，的確(que)，醋是(shi)PH值小(xiao)于(yu)7的酸性(xing)(xing)物質，但(dan)作(zuo)為食(shi)(shi)品他確(que)是(shi)堿性(xing)(xing)的。酸性(xing)(xing)物質和酸性(xing)(xing)食(shi)(shi)品是(shi)兩個概念。

世(shi)界的真實面目并(bing)不總(zong)是你(ni)從(cong)它(ta)表(biao)面感知到的那樣，比如我們熟知的酸醋(cu)。

酸(suan)醋(cu)的學名(ming)叫乙酸(suan)，分子式為CH3COOH。在被人體(ti)吸收代謝之前，它是(shi)不折不扣的酸(suan)性物質(zhi)。

所(suo)謂(wei)酸(suan)(suan)性(xing)物(wu)(wu)質(zhi)(zhi)，根據阿瑞(rui)尼士( S. Arrhenius) 的酸(suan)(suan)堿學說，是指(zhi)該物(wu)(wu)質(zhi)(zhi)水(shui)溶液中(zhong)游離(li)(li)出，或與水(shui)作(zuo)用后(hou)產生的氫(qing)離(li)(li)子(H+)數(shu)量比氫(qing)氧根離(li)(li)子(OH-)數(shu)量多的物(wu)(wu)質(zhi)(zhi)。反之(zhi)，如果OH-的數(shu)量占(zhan)主(zhu)導(dao)量，則該物(wu)(wu)質(zhi)(zhi)為(wei)堿性(xing)。酸(suan)(suan)醋溶解于水(shui)后(hou)，產生的H+離(li)(li)子占(zhan)據了主(zhu)導(dao)量，此時它(ta)呈酸(suan)(suan)性(xing)。如果用酸(suan)(suan)堿指(zhi)標pH值衡量，氫(qing)離(li)(li)子(H+)數(shu)量越多，pH值越低;(OH-)數(shu)量多，則pH值越高。一般(ban)而(er)言，所(suo)有酸(suan)(suan)味的物(wu)(wu)質(zhi)(zhi)都是酸(suan)(suan)性(xing)物(wu)(wu)質(zhi)(zhi)。

然(ran)(ran)(ran)而自(zi)然(ran)(ran)(ran)界的(de)(de)造(zao)化(hua)是(shi)神奇的(de)(de)。這(zhe)種奇妙的(de)(de)造(zao)化(hua)最(zui)集中(zhong)地體現在生(sheng)命的(de)(de)新陳代謝(xie)(xie)上。大自(zi)然(ran)(ran)(ran)將宇宙中(zhong)最(zui)復(fu)雜(za)的(de)(de)化(hua)學反(fan)(fan)應給予(yu)了生(sheng)命，于(yu)是(shi)自(zi)然(ran)(ran)(ran)態下原本單一(yi)的(de)(de)判斷(duan)標(biao)準在生(sheng)命體那里變得(de)不(bu)再單一(yi)，這(zhe)是(shi)化(hua)學反(fan)(fan)應變成高級的(de)(de)生(sheng)命反(fan)(fan)應的(de)(de)過程。當酸(suan)(suan)(suan)醋從化(hua)學領域(yu)步入(ru)食(shi)物(wu)(wu)(wu)營養領域(yu)之(zhi)后(hou)(hou)(hou)，酸(suan)(suan)(suan)醋成了堿(jian)(jian)性(xing)(xing)(xing)(xing)(xing)食(shi)品。酸(suan)(suan)(suan)/堿(jian)(jian)物(wu)(wu)(wu)質和酸(suan)(suan)(suan)性(xing)(xing)(xing)(xing)(xing)/堿(jian)(jian)性(xing)(xing)(xing)(xing)(xing)食(shi)品是(shi)兩對不(bu)同的(de)(de)概念(nian)。酸(suan)(suan)(suan)性(xing)(xing)(xing)(xing)(xing)/堿(jian)(jian)性(xing)(xing)(xing)(xing)(xing)食(shi)品的(de)(de)酸(suan)(suan)(suan)堿(jian)(jian)度(du)與(yu)進入(ru)人(ren)體之(zhi)前(qian)的(de)(de)物(wu)(wu)(wu)質酸(suan)(suan)(suan)堿(jian)(jian)度(du)沒(mei)有(you)必然(ran)(ran)(ran)的(de)(de)聯(lian)系。判斷(duan)食(shi)物(wu)(wu)(wu)的(de)(de)酸(suan)(suan)(suan)性(xing)(xing)(xing)(xing)(xing)和堿(jian)(jian)性(xing)(xing)(xing)(xing)(xing)，主(zhu)要看(kan)食(shi)物(wu)(wu)(wu)中(zhong)所(suo)含(han)(han)的(de)(de)堿(jian)(jian)性(xing)(xing)(xing)(xing)(xing)元(yuan)(yuan)素、酸(suan)(suan)(suan)性(xing)(xing)(xing)(xing)(xing)元(yuan)(yuan)素和有(you)機酸(suan)(suan)(suan)在人(ren)體內代謝(xie)(xie)后(hou)(hou)(hou)的(de)(de)結果。通(tong)常，簡單的(de)(de)判定方法為：凡含(han)(han)氯、硫、磷(lin)等(deng)非金屬元(yuan)(yuan)素較(jiao)高的(de)(de)食(shi)物(wu)(wu)(wu)，因其(qi)被攝(she)(she)入(ru)人(ren)體后(hou)(hou)(hou)最(zui)終的(de)(de)代謝(xie)(xie)產(chan)物(wu)(wu)(wu)呈酸(suan)(suan)(suan)性(xing)(xing)(xing)(xing)(xing)，多為酸(suan)(suan)(suan)性(xing)(xing)(xing)(xing)(xing)食(shi)物(wu)(wu)(wu); 含(han)(han)鈣、鉀、鈉、鎂等(deng)金屬元(yuan)(yuan)素較(jiao)高的(de)(de)食(shi)物(wu)(wu)(wu)，因其(qi)被攝(she)(she)入(ru)人(ren)體后(hou)(hou)(hou)最(zui)終代謝(xie)(xie)產(chan)物(wu)(wu)(wu)呈堿(jian)(jian)性(xing)(xing)(xing)(xing)(xing)，多為堿(jian)(jian)性(xing)(xing)(xing)(xing)(xing)食(shi)物(wu)(wu)(wu)。