當原淀(dian)(dian)(dian)粉(fen)加(jia)水調(diao)漿(jiang)加(jia)熱后會發(fa)生(sheng)糊(hu)化(hua)(hua)(hua)現象(xiang)，不同種類淀(dian)(dian)(dian)粉(fen)的(de)糊(hu)化(hua)(hua)(hua)溫(wen)度(du)是(shi)不相同的(de)。根據淀(dian)(dian)(dian)粉(fen)顆粒吸(xi)水膨(peng)(peng)脹(zhang)(zhang)和粘度(du)增(zeng)大．以及偏(pian)光特性(xing)的(de)改(gai)變(bian)(bian)，其(qi)糊(hu)化(hua)(hua)(hua)的(de)過程可分(fen)為粉(fen)乳中水分(fen)子被淀(dian)(dian)(dian)粉(fen)粒無定型(xing)區極性(xing)基吸(xi)附并(bing)加(jia)熱到(dao)初(chu)始糊(hu)化(hua)(hua)(hua)前的(de)可逆膨(peng)(peng)脹(zhang)(zhang)階段(duan)(duan)，淀(dian)(dian)(dian)粉(fen)粒只是(shi)稍有膨(peng)(peng)脹(zhang)(zhang)，但尚未改(gai)變(bian)(bian)原有物性(xing)，偏(pian)光十字仍然存(cun)在；繼(ji)續加(jia)溫(wen)達到(dao)糊(hu)化(hua)(hua)(hua)開始溫(wen)度(du)的(de)不可逆膨(peng)(peng)脹(zhang)(zhang)階段(duan)(duan)，這時，淀(dian)(dian)(dian)粉(fen)分(fen)子晶(jing)區發(fa)生(sheng)水合(he)作(zuo)用，大量(liang)吸(xi)水膨(peng)(peng)脹(zhang)(zhang)，變(bian)(bian)成粘稠(chou)的(de)膠體溶液，改(gai)變(bian)(bian)原有物性(xing)，偏(pian)光十字也(ye)消失；再(zai)繼(ji)續加(jia)溫(wen)，粘度(du)增(zeng)高(gao)并(bing)達到(dao)高(gao)峰值。此后，粘度(du)則(ze)開始下降。糊(hu)化(hua)(hua)(hua)初(chu)始表(biao)觀溫(wen)度(du)和糊(hu)化(hua)(hua)(hua)溫(wen)度(du)范圍與測定方法、淀(dian)(dian)(dian)粉(fen)與水比(bi)例、顆粒類型(xing)、顆粒內部分(fen)布不均勻有關(guan)。因(yin)此，研究淀(dian)(dian)(dian)粉(fen)糊(hu)性(xing)質極為重要。

從圖中(zhong)可以(yi)看出(chu)玉(yu)米(mi)(mi)淀(dian)(dian)(dian)(dian)粉(fen)(fen)(fen)凝(ning)(ning)膠(jiao)力(li)強，小(xiao)(xiao)麥粉(fen)(fen)(fen)和大米(mi)(mi)粉(fen)(fen)(fen)凝(ning)(ning)膠(jiao)力(li)較(jiao)強，糯(nuo)米(mi)(mi)淀(dian)(dian)(dian)(dian)粉(fen)(fen)(fen)沒有凝(ning)(ning)膠(jiao)力(li)；馬(ma)(ma)鈴薯(shu)(shu)和木薯(shu)(shu)淀(dian)(dian)(dian)(dian)粉(fen)(fen)(fen)凝(ning)(ning)膠(jiao)力(li)弱。是因為(wei)不同(tong)作物，其(qi)中(zhong)的(de)直鏈淀(dian)(dian)(dian)(dian)粉(fen)(fen)(fen)與支鍵(jian)淀(dian)(dian)(dian)(dian)粉(fen)(fen)(fen)的(de)比例各(ge)(ge)不相同(tong)。普通玉(yu)米(mi)(mi)淀(dian)(dian)(dian)(dian)粉(fen)(fen)(fen) 2.7:7.3．大米(mi)(mi)淀(dian)(dian)(dian)(dian)粉(fen)(fen)(fen) 1.7 :8.3，糯(nuo)米(mi)(mi)淀(dian)(dian)(dian)(dian)粉(fen)(fen)(fen) 0：10，小(xiao)(xiao)麥淀(dian)(dian)(dian)(dian)粉(fen)(fen)(fen) 2.5:7.5，馬(ma)(ma)鈴薯(shu)(shu)淀(dian)(dian)(dian)(dian)粉(fen)(fen)(fen) 2：8，木薯(shu)(shu)淀(dian)(dian)(dian)(dian)粉(fen)(fen)(fen) 1.7:8.3。直鏈淀(dian)(dian)(dian)(dian)粉(fen)(fen)(fen)在水中(zhong)加熱糊化后，是不穩定(ding)的(de)，會(hui)迅速老化而逐步形成凝(ning)(ning)膠(jiao)體。這種凝(ning)(ning)膠(jiao)體較(jiao)硬(ying)，需在 115～ 120℃ 的(de)溫度才能向反方向轉化。支鏈淀(dian)(dian)(dian)(dian)粉(fen)(fen)(fen)在水溶液中(zhong)穩定(ding)，發生(sheng)凝(ning)(ning)膠(jiao)作用(yong)的(de)速率比直鏈淀(dian)(dian)(dian)(dian)粉(fen)(fen)(fen)緩(huan)慢得多，且凝(ning)(ning)膠(jiao)柔軟。各(ge)(ge)種淀(dian)(dian)(dian)(dian)粉(fen)(fen)(fen)困直鏈淀(dian)(dian)(dian)(dian)粉(fen)(fen)(fen)的(de)含量、分子大小(xiao)(xiao)及(ji)其(qi)聚合度的(de)不同(tong)，其(qi)它特性也存(cun)在差異。

上(shang)海保圣(sheng)快速粘(zhan)度(du)(du)分(fen)析儀（Rapid Visco Analyzer，RVA）可用于(yu)淀粉(fen)糊(hu)化粘(zhan)度(du)(du)的測(ce)定。從(cong)RVA可讀出(chu)峰值(zhi)(zhi)粘(zhan)度(du)(du)（Peak Viscosity，PV）、熱糊(hu)粘(zhan)度(du)(du)（Hot Paste Viscosity，HPV）、冷糊(hu)粘(zhan)度(du)(du)（Cool Paste Viscosity，CPV），并(bing)可進一(yi)步計算(suan)出(chu)崩解值(zhi)(zhi)（Breakdown）、回升值(zhi)(zhi)（Setback）等參數(shu)。峰值(zhi)(zhi)粘(zhan)度(du)(du)是(shi)由于(yu)充分(fen)吸水膨(peng)脹(zhang)(zhang)后(hou)(hou)淀粉(fen)粒(li)（膨(peng)潤粒(li)）相互摩擦而(er)(er)使糊(hu)液(ye)粘(zhan)度(du)(du)增大，反(fan)映(ying)淀粉(fen)膨(peng)脹(zhang)(zhang)能力(li)。熱糊(hu)粘(zhan)度(du)(du)是(shi)由于(yu)淀粉(fen)粒(li)膨(peng)脹(zhang)(zhang)后(hou)(hou)破(po)裂而(er)(er)不再相互摩擦，糊(hu)液(ye)粘(zhan)度(du)(du)急劇下降(jiang)，能反(fan)映(ying)淀粉(fen)在(zai)高溫下耐(nai)剪切能力(li)，是(shi)影(ying)響食品加工操作難(nan)易重要因素。冷糊(hu)粘(zhan)度(du)(du)是(shi)由于(yu)溫度(du)(du)降(jiang)低后(hou)(hou)直(zhi)鏈淀粉(fen)和支鏈淀粉(fen)所包圍水分(fen)子運動減弱(ruo)，糊(hu)液(ye)粘(zhan)度(du)(du)再度(du)(du)升高，反(fan)映(ying)淀粉(fen)回生(sheng)特性。

對使(shi)用上海保(bao)(bao)圣(sheng)快速(su)粘(zhan)度(du)(du)(du)分析儀RVA測試(shi)(shi)淀粉質試(shi)(shi)樣所得(de)到糊化曲線作簡要解釋和說(shuo)明。采(cai)用典型“加(jia)熱→保(bao)(bao)持→冷卻(que)"測試(shi)(shi)循環。快速(su)粘(zhan)度(du)(du)(du)分析儀RVA是一(yi)種由微(wei)處理器控制，能對試(shi)(shi)樣施(shi)加(jia)可(ke)(ke)改變溫(wen)度(du)(du)(du)和剪切力，同時還能連續檢測試(shi)(shi)樣粘(zhan)度(du)(du)(du)的(de)儀器，且具備便捷的(de)操作軟(ruan)件，如可(ke)(ke)設定測試(shi)(shi)程序、測試(shi)(shi)溫(wen)度(du)(du)(du)、攪拌(ban)器轉(zhuan)速(su)、時間和pH值等(deng)，能很好與(yu)實際加(jia)工(gong)(gong)工(gong)(gong)藝擬合(he)。快速(su)粘(zhan)度(du)(du)(du)分析儀RVA工(gong)(gong)作原理是將產(chan)品復煮，測定淀粉轉(zhuan)化程度(du)(du)(du)來分析熟化度(du)(du)(du)，可(ke)(ke)用于在線工(gong)(gong)藝控制、產(chan)品開發、計量、輸送、故障排除和競爭性(xing)產(chan)品分析。快速(su)粘(zhan)度(du)(du)(du)分析儀RVA測定所需時間一(yi)般(ban)不超過(guo)20 min，需要樣品量為2~4 g，獲(huo)得(de)信(xin)息結果為糊化溫(wen)度(du)(du)(du)、粘(zhan)度(du)(du)(du)及粘(zhan)度(du)(du)(du)間關系。