挑選的脫皮豆類混合大米壓縮物的液流學(xué)與營養(yǎng)學(xué)的質(zhì)量 【中文4846字】【PDF+中文WORD】

挑選的脫皮豆類混合大米壓縮物的液流學(xué)與營養(yǎng)學(xué)的質(zhì)量 【中文4846字】【PDF+中文WORD】,中文4846字,PDF+中文WORD,挑選的脫皮豆類混合大米壓縮物的液流學(xué)與營養(yǎng)學(xué)的質(zhì)量,【中文4846字】【PDF+中文WORD】,挑選,脫皮,豆類,混合,大米,壓縮,液流學(xué),營養(yǎng)學(xué),質(zhì)量,中文,4846 【中文4846字】 精選的脫皮豆類混合大米壓縮物的液流學(xué)與營養(yǎng)學(xué)的質(zhì)量 S. Balasubramaian & Anjan Borah & K. K. Singh &R. T. Patil 摘要：人們通過最小成本的夾頭壓縮機(jī)對即食大米及其豆類（如黑豆，綠豆，小扁豆和豌豆）的基本壓縮物的研究。壓縮物是通過維持不變的供給率與保濕成分及其在15%的豆類混合水平下制備而成的。由壓縮面粉做成的稀飯的液流學(xué)性質(zhì)通過使用快速黏膠分析機(jī)進(jìn)行評估。大米壓縮物的最大及其最小的黏膠性是697cp.，大米混合物與15%的豌豆的黏膠性是523cp，對豆類混合物的水平增加，.黏膠的程度呈減少的趨勢。其他的快速黏膠分析機(jī)的液流學(xué)參數(shù)，像在轉(zhuǎn)折階段，中間階段及其最后階段的黏膠性 分別是266cp-226cp.,431-297cp,452-375cp.在大米壓縮物與混合15%的豆類中發(fā)現(xiàn) 最大價值的蛋白質(zhì)，脂肪，纖維和灰末成分的存在。 大米壓縮物內(nèi)加上豆類成分，營養(yǎng)值呈現(xiàn)出增加的趨勢。僅僅是大米壓縮物的膠凝程度是在29.4%，與加上豆類混合物的膠凝度上呈現(xiàn)個降低的趨勢，也只是大米混合15%的脫皮豆類的最小膠凝度。 所有的壓縮物的感官評估價值的得分呈現(xiàn)出最讓人接受的范圍：6至8.因此，脫皮豆類的豆類混合水平獲得了好的分?jǐn)?shù)，并且對低成本的膨脹壓縮物及其速溶粉的生產(chǎn)展呈現(xiàn)出很大的趨向。 關(guān)鍵詞：大米，脫皮豆類，壓縮物，感官質(zhì)量，營養(yǎng) 簡介 擠壓烹飪是生產(chǎn)膨脹消除與速溶粉的有效加工法之一。，在擠壓烹飪中，經(jīng)過高度扭曲的原材料因此允許部分的淀粉水解。 固有的擠壓系統(tǒng)需要跟高的金融投資，生產(chǎn)能力于及技術(shù)知識。，這就不適用與發(fā)展中國家。 為生產(chǎn)輔食，在20世紀(jì)八十年代初期，科羅拉多大學(xué)研發(fā)了的單個的夾頭擠壓機(jī)/干燥擠壓機(jī)除了擁有高生產(chǎn)力，但是還需要花昂貴的成本。在發(fā)展中國家，對速溶粉生產(chǎn)的擠壓烹飪加工還未被采用。因此，具有很小的生產(chǎn)力的簡單機(jī)器的使用還是具有潛在的利益的。為了研究小吃與速溶粉的生產(chǎn)，還需要對低成本的夾頭擠壓機(jī)的可能性進(jìn)行研究。大米，是制作無骨蛋白食物最常用的谷類之一。豆類是植物蛋白，卡路里及其他營養(yǎng)的主要來源。豆類的擠壓烹飪增加了豆類營養(yǎng)的消化。 圖1一低成本擠出機(jī)夾頭 主視圖 側(cè)視圖 圖1 在產(chǎn)品研發(fā)期間，為對加工期間與加工之后的產(chǎn)品行為的理解，最高與最后的膠凝度是最重要的參數(shù)。快速粘彈普儀可以用來調(diào)查脂肪的黏膠效應(yīng)與大米淀粉和米粉的氨基酸。擠壓加工的緊密結(jié)構(gòu)能夠構(gòu)建一個緊密的營養(yǎng)網(wǎng)，以便減少液化淀粉酶對淀粉顆粒的侵襲。 再者，由營養(yǎng)網(wǎng)創(chuàng)造的物理障礙限制了對淀粉酶的淀粉可取性，并且延誤其在試管內(nèi)的水解作用。 各種報告顯示，膠凝的特性，漿糊的流變性能，膠體和其他的淀粉功能性質(zhì)隨物種和變體的變化 而變化。淀粉的凝膠性性能取決于種類，顆粒的結(jié)構(gòu)，植物的起源和淀粉的比例。糯米和一般水稻在60至78℃時可凝膠化。許多因素影響了食物的偏好與接受性。許多因素是產(chǎn)品固有的，比如表面，味道和氣味，其他外在的因素，如社會文化因素。 圖2典型參數(shù)快速粘度分析儀粘度專為豆類混合飯擠壓 圖2 測試時間.分鐘 表1粘滯性譜參數(shù) 性狀縮寫 描述（術(shù)語參考） PV 峰值粘度（61-02，1999年） T 海槽（61-02） BD 擊穿（寶和1999年夏，61-02），降低在烹飪過程中粘度在95℃ FV 在最后時刻結(jié)束糊粘度期間在50℃ 把以上的點作為目標(biāo)，現(xiàn)在的工作是研究精選出脫皮豆類混合大米壓縮物的液流學(xué)和營養(yǎng)學(xué)的質(zhì)量。 原料與方法 不同的脫皮豆類，如黑豆，綠豆，小扁豆和豌豆與精米都是從當(dāng)?shù)厥袌鲑徺I的。通過清理與分級，原材料放在在粗超的扎板機(jī)表面是為了制成1.65-2.36mm顆粒大小的玉米片。在0，5,10與15%混合水平的不同豆類玉米片被與大米玉米片混合。為制出擠壓物，需要2KG的加濕至14%濕度的混合原料。 低成本的擠壓機(jī)，它是一個小的單個螺釘自動擠壓機(jī)，由7.5KW的電動馬達(dá)所驅(qū)動。 它 的芯管是250mm的，直徑率為6:1.，和一個4mm直徑，5mm長度的圓柱體的刀模。螺釘?shù)霓D(zhuǎn)動速度高，可允許高度扭曲。螺釘構(gòu)型有個定螺距，螺紋深度克允許摩擦力與芯管內(nèi)溫度的遞增。螺釘?shù)闹睆绞?2.5mm，根部直徑是32.5mm..含濕量保持在14%。擠壓機(jī)的芯管墻有個螺旋槽，可以增加產(chǎn)品的摩擦和烹調(diào)。為確保正常的供給率，擠壓機(jī)裝置了一個保濕螺釘，在研究中它不會被改變。 擠壓之后，壓縮物是磨碎的，并把 液流學(xué)與營養(yǎng)學(xué)的分析列為主題。 流變學(xué)性能,擠壓的粉末黏膠性能是使用第162個方法，通過粘膠分析儀 （MODEL -3 –D）的3.0版本的變溫軟件而得出的。樣品 懸浮是通過在放有蒸餾水的鋁筒里放入3g擠壓的粉末準(zhǔn)備而成的。一個程序化的加熱與冷卻系統(tǒng)在這就使用了。每種樣品在加溫至50℃的時候進(jìn)行攪拌，剩下的加工過程中保持不變的扭曲率。溫度保持在50℃，持續(xù)1分鐘。 測試時間（秒） 測試時間（秒） 圖3典型的快速粘混紡不同糙大米儀積擠壓 圖4 度糊化大米混合不同糙擠壓 豆類團(tuán)的水平，％ 然后樣品加熱在95℃，持續(xù)2分30秒。，之后，樣品冷卻至50℃，持續(xù)2分鐘。一個粘性坐標(biāo)曲線的快速黏膠分析儀的繪圖被用于決定最高的粘性，低谷期的粘性，衰落期的粘性以及最后的粘性。每種分析都進(jìn)行過兩次。 營養(yǎng)學(xué)的分析。不同豆類混合大米壓縮物決定了營養(yǎng)成分，脂肪與灰末和纖維。擠壓物的粘膠性的程度 被Wootton 研究。 感官評價。由11個成員主城的辦培訓(xùn)的專家小組評估擠壓物。如顏色，氣味，表面處理，氣味，松脆性和所有的擠壓物的可接受性等感官的特性被用9點的快感標(biāo)度來評價（1—4點，非常不喜歡至輕微的不喜歡，5點，即喜歡也不喜歡。6-9點喜歡至稍微喜歡。樣品在經(jīng)過加溫至105℃，持續(xù)三分鐘，后供給評價小組服用。 數(shù)據(jù)分析所報告出來的數(shù)據(jù)是10中觀察的平均數(shù)，并是以MS EXCEL 2000 為準(zhǔn)的。 結(jié)果與討論 低成本的擠壓機(jī)對擠壓物表面的粘性的作用，所有的粘性參數(shù)決定著與單個的大米擠壓物相比下的豆類的混合水平增長與降低。但是，綠色谷物的一般擠壓物的粘性減弱不是很明顯。在低谷期的粘性，豌豆最大，因此變化范圍在288-297cp，是所有品種中比較低的。最后的粘性在所有的品種中都在下降，但是，降低的程度比綠豆高，從437cp變至404cp。在最高階段的粘性的相似的觀察已經(jīng)被記錄。 當(dāng)擠壓粉末懸浮液加溫至以上一定的溫度，水?dāng)z入顆粒內(nèi)，減弱了淀粉段內(nèi)的氫鍵，由于機(jī)械的輸入，與它一致的原材料相比，反射出一個趨向下降的快速黏膠性分析儀輪廓。這種粘性在加溫至95℃時會加強(qiáng)，在冷卻時繼續(xù)降低，最后圖像顯示：不同豆類與混合水平呈現(xiàn)出穩(wěn)定的趨勢，單在加工的最后階段顯示出稍微的上升趨向。所有研究系統(tǒng)的粘性溫度圖像都是簡單的模式。 表2 營養(yǎng)分析不同糙豆類混合擠壓大米 豆類 豆類% 蛋白質(zhì)% 脂肪% 纖維% 灰分% 黑豆 0 8.6 0.86 0.19 0.56 5 9.2 0.90 0.25 0.62 10 9.8 0.96 0.27 0.78 15 10.5 1.03 0.29 0.96 綠豆 0 8.6 0.86 0.19 0.56 5 9.7 0.90 0.24 0.74 10 10.1 0.96 0.26 0.88 15 10.9 1.02 0.28 0.98 小扁豆 0 8.6 0.86 0.19 0.56 5 9.7 0.90 0.23 0.66 10 10.1 0.96 0.25 0.76 15 11.2 1.03 0.27 0.88 豌豆 0 8.6 0.86 0.19 0.56 5 9.0 0.90 0.32 0.66 10 9.6 0.96 0.39 0.78 15 10.2 1.03 0.50 0.86 當(dāng)顆粒在其最腫脹的狀態(tài)時，它的粘性最大，在最高的粘性時任然保持完好的在這個階段可堅持加熱，然而，顆粒的破碎便會使得粘性降低。粘性在冷卻階段的第二次增加和衰減現(xiàn)象及其所觀察到的淀粉成分有關(guān)。 粘性程度的影響。大米壓縮物的粘性程度是%29.4.粘性變化范圍是：22.4至29.4%。 豆類混合壓縮物同大米壓縮物相比，粘性稍低。在15%的水平時的豆類混合壓縮物之間的粘性程度沒有太大的差異，黑豆和綠豆的粘性卻是稍低的 （22.4%和22.6%），隨之在后的是豌豆（23.3%）與小扁豆（（23.2%）。部分的淀粉糊化是合適的，因為在糊化準(zhǔn)備時減少了腫脹，因此為維持在較高的濃度可允許合適的半液體稠度。也就是，高能量密度。這個也就指明 擠壓烹飪已經(jīng)提高了壓縮物的膠凝程度。根據(jù)LIN et.al. 壓縮物的脂肪成分 嚴(yán)重影響了淀粉膠凝度。因此，同大米一樣，豆類混合的膠凝度減低是由于 營養(yǎng)和脂肪的增加水平。 營養(yǎng)價值的影響。大米，黑豆，綠豆，小扁豆及其豌豆分別是6%，8%，24%，19.7%，25.1%與19.7%的營養(yǎng)值。大米和豆類的混合形成了一種營養(yǎng)豐富的食物。豆類混合大米壓縮物的營養(yǎng)成分范圍是：8.6%至11.15%。在壓縮物中，同豆類相比，大米的營養(yǎng)成分低。營養(yǎng)成分的高低取決于豆類的種類。這也許是應(yīng)為豆類本身就有很高的營養(yǎng)成分。小扁豆混合大米壓縮物呈現(xiàn)最高的營養(yǎng)成分。僅僅是由大米做成的壓縮物，或是單獨的豆類混合大米壓縮物都呈現(xiàn)出低的脂肪百分?jǐn)?shù)：0.86%至1.03%，而玄米是：（0.5%）和豆類：如：黑豆，綠豆，小扁豆，豌豆。在豆類之間脂肪沒有很大的差別，綠豆除外，呈現(xiàn)出較低的價值。大米和豆類混合大米壓縮物的纖維成分范圍是0.19%至0.5%。 隨著豆類成分的增加，壓縮物的纖維成分呈現(xiàn)出增長的趨勢：因為豆類的纖維成分比大米的高。 豌豆在水平上混合大米壓縮物顯示出更高的纖維價值。 灰末壓縮物成分隨著豆類水平的增加而增加?；夷┏煞址秶牵?.56%至0.98%。黑豆和綠豆混合壓縮物呈現(xiàn)出高點的灰末成分（0.96%和0.98%），小扁豆（0.88%）和豌豆（0.86%）在其后。 感官特性的影響。在所有的例子中，感官屬性也明顯地被豆類水平影響。 然而，同綠豆和小扁豆基本壓縮物為相比，黑豆和豌豆混合壓縮物在整體的范圍內(nèi)并沒有顯示出太多的變化，這也許是應(yīng)為豆類的內(nèi)在顏色特征。 表5 擠壓由不同粗糙度混合而成的大米享樂分?jǐn)?shù) 黑豆 綠豆 顏色 顏色 脆度 表面處理 脆度 表面處理 味道 味道 顏色 顏色 脆度 表面處理 脆度 表面處理 味道 味道 然而，同單單的大米壓縮物相比，在沒有變化整體可接受性分?jǐn)?shù)，黑豆（15%），豌豆（15%）綠豆（10%）及其小扁豆（10%）的混合水平是可以接受的。 結(jié)論 帶有小生產(chǎn)力的低成本擠壓機(jī)適合加工和生產(chǎn)豆類混合大米膨脹小吃食物與帶有低水分和低液體成分的速溶粉。在經(jīng)過加工中，被部分糊化和膠化的擠壓粉，可縮性的速溶粉顯示了高能量密度顆粒的制備范圍。壓縮粉的低粘性圖像與原始成分的粉，高營養(yǎng)及其高感官價值相比，揭示出產(chǎn)品發(fā)展的用處和可能性，尤其是為正餐和輔食。 參考文獻(xiàn) 科隆納磷，Doublier巨浪，Melcion太平紳士，德Monredon樓名士的c（1984）擠壓蒸煮小麥淀粉和滾筒干燥。一，物理和大分子的修改。谷物化學(xué)61:538-544 Deliza001麥菲小時，Hedderley D類（1996）信息影響消費者評估甜和苦的解決方案。 ?食品科學(xué)61:1080-1083 Fardet甲，Abecassis J號，Hoebler?，鮑德溫下午，Buleon甲，Berot S（1999年）的影響蛋白質(zhì)的技術(shù)修改從面食網(wǎng)絡(luò)對體外淀粉降解。?谷物科技30:133-145 Gopalan?，拉瑪沙斯特里法國BV，Balasubramanian資深大律師（1991）營養(yǎng)印度食品的價值。國家營養(yǎng)研究所，印度醫(yī)學(xué)研究理事會，海得拉巴，頁47-48-95-96 哈珀雜志（1995年）的低成本擠壓：非洲的可能性。該南部非洲?食品科學(xué)Nutr7:142-147 哈珀J號，揚森克（1985）預(yù)煮食品的生產(chǎn)中營養(yǎng)發(fā)展中國家的低成本擠壓技術(shù)的國家。食品 馮詮釋1:27-97 哈特佛羅里達(dá)州，菲舍爾黃建忠（1971）變遷探析moderno德洛斯alimentas。在：Acribia，薩拉戈薩 Hoebler?，Karinthi一個契諾小時，冠軍男，巴里巨浪（1999）生物利用度的淀粉在面包中含有豐富的淀粉酶：代謝正常人的反應(yīng)和淀粉的結(jié)構(gòu)。歐元?臨床Nutr53:360-366 國際刑事法院（1995）快速粘貼方法使用快速粘紐波特分析儀。國際刑事法院的第162號標(biāo)準(zhǔn)草案，國際交流協(xié)會谷物科學(xué)與技術(shù) 詹金斯女士，詹金斯鋁，Wolever訓(xùn)練管理系統(tǒng)，Vuksan五，饒影音，湯普森陸，若斯的RG（1994）低血糖指數(shù)：Lente碳水化合物和改變飲食頻率的生理影響。上午?臨床Nutr 59:706的S - 709S基爾斯利兆瓦，西卡德pj的（1989）淀粉及糖類的化學(xué)存在于食物。見：Dobbing雜志（ED）的淀粉和糖的飲食男子：一比較。斯普林格，倫敦，頁1-34 金涌，Wiesenborn DP的，奧爾PH值，格蘭特洛杉磯（1995年）篩選馬鈴薯新型淀粉用差示掃描量熱性能。?食品科學(xué)60:1060-1065 賴陛下（2001年）的理化處理對水熱物業(yè)預(yù)糊化米粉。食品化學(xué)72:455-463 梁訓(xùn)明，王譯（2003）糊化和結(jié)晶性能的差異商業(yè)和孤立的大米淀粉，并補充氨基酸酸。?食品科學(xué)68:832-838 梁訓(xùn)明，王謨，施法郎（2002年）糊化特性差異商業(yè)和孤立添加了大米血脂和β淀粉環(huán)糊精。谷物化學(xué)79:812-818 林秒，Hseih樓吞吐他（1997年）對血脂和加工條件對淀粉糊化度擠壓干寵物食品。Lebens Wiss Technol 30:754-761 Sadasivam秒，一馬尼卡姆（1992）農(nóng)業(yè)生物化學(xué)方法科學(xué)。威利，新德里，頁20-21 說凈重（2000）干擠出機(jī)。見：里亞茲百萬（ED）的擠出機(jī)在食品申請。Technomic，德州，頁51-62 Sajilata爵，阿密特遙感，庫卡尼公關(guān)（2006）抗性淀粉，一審查。比賽牧師食品科學(xué)食品安全5:1-17 Sivaramakrishnan惠普，圣吉乙，Chattopadhyay的PK（2004年）的流變面團(tuán)特性的水稻稻米制作面包。?食品工程62:37-45 索伯恩仙，品牌金城，富鼎的AS（1987）慢慢消化，吸收傳統(tǒng)bushfoods碳水化合物：一個保護(hù)因子對糖尿病？上午?臨床Nutr 45:98-106 Wiesenborn的DP，奧爾PH值，卡斯帕爾HH中Tacke銀行（1994）馬鈴薯淀粉粘貼行為，相關(guān)的一些物理/化學(xué)性質(zhì)。?食品科學(xué)59:644-648 沃頓男，Bamunuarachchi甲（1978）水結(jié)合能力商業(yè)生產(chǎn)的天然和改性淀粉。淀粉/斯塔克33:159-161 伍頓男，威敦研發(fā)，芒克氮（1971年）為快速的方法估計加工食品中淀粉糊化。食品Technol澳大利亞23:612-615 Zobel高頻（1984）糊化淀粉及力學(xué)性能淀粉糊。見：惠斯勒RL，BeMiller劍南，帕斯卡爾英法（EDS）等淀粉：化學(xué)與技術(shù)，第二版。學(xué)術(shù)，倫敦，頁285-309 ORIGINAL ARTICLERheological and nutritional quality of selected dehulledlegumes blended rice extrudatesS.Balasubramanian&Anjan Borah&K.K.Singh&R.T.PatilRevised:3 November 2010/Accepted:18 December 2010#Association of Food Scientists&Technologists(India)2011Abstract Rheological and nutritional quality of ready-to-eat rice(Oryza sativa)-legume viz.black gram(Vignamungo),green gram(Vigna radiata),lentil(Lens culinaris)and peas(Pisum sativum)based extrudates were studiedusing low cost collet extruder.Extrudates were preparedkeeping constant feed rate(25 kg/h)and moisture content(14%wb)at 0,5,10 and 15%legume incorporation levels.Rheological properties of porridge made of extrudate flourwere evaluated using Rapid Visco Analyser(RVA).Maximum and minimum peak viscosity for rice extrudatesalone and rice extrudates blended with 15%peas were 697cp and 523 cp,respectively.There was a decreasing trend indegree of gelatinization with increase in legume incorpora-tion level.Other RVA rheological parameters like troughbreak down and final viscosity were in the range of 266-226 cp,431-297 cp and 452-375 cp respectively.Maximumvalues of protein,fat,fibre and ash contents were found inrice extrudates at 15%legumes blend levels.There was anincreasing trend in nutrient contents with legume content inrice extrudates.Degree of gelatinization for rice aloneextrudate was 29.4%and showed a decrease in gelatiniza-tion with increase in legumes extrudate and was minimum(22.4%)for rice blended with 15%dehulled green gram.Sensory evaluation scores for all extrudates showed themost acceptable range of 6 to 8.Thus,legume blend level(up to 15%)of dehulled legumes fetched good scores andshowed promising trend for the production of low costexpanded extrudates and its instant flour.Keywords Rice.Dehulled legumes.Extrudates.Sensoryquality.NutritionIntroductionExtrusion cooking is one of the useful processes for theproduction of expanded snacks and instant flours.Duringextrusion cooking,raw materials undergo high shear,thus allowing partial starch hydrolysis(Colonna et al.1984).The existing extrusion systems involve higherfinancial investment,production capacity and technicalknowledge and are not suitable for developing countries.Single collet extruders/dry extruders that were developedfor complementary foods production during early 1980sby the University of Colorado(Harper 1995,Harper andJansen 1985,Said 2000)are too costly besides highproduction capacity(about Rs 2.5 million and 1 t/h).Adoption of extrusion cooking processing for instant flourproduction in developing countries has not still picked up.Thus,application of simple machine having small pro-duction capacity is therefore of great potential interest.The possibilities of a low cost collet extruder(about 2535 kg/h)need to be studied for the production of snackfoods and instant flours.Rice(Oryza sativa),is one of themost frequently used cereals for making gluten-free foodproducts(Sivaramakrishnan et al.2004).Legumes are aprime source of plant proteins,calories and othernutrients.Extrusion cooking of legumes increases thedigestibility of legume protein.In product development,peak and final viscosities are important parameters,tohave an understanding of product behaviour during andS.Balasubramanian(*):K.K.Singh:R.T.PatilCentral Institute of Post Harvest Engineering and Technology,PAU Campus,Ludhiana 141 004 Punjab,Indiae-mail:A.BorahTezpur University,Tezpur 784 028 Assam,IndiaJ Food Sci TechnolDOI 10.1007/s13197-010-0206-yafter processing.Rapid viscoanalyser can be used toinvestigate the pasting effects of lipids and amino acidson rice starch and flour(Liang et al.2002,Liang and King2003).The compact structure resulting from extrusionprocess can lead to a dense protein network reducing theavailability of starch granules to attack by alpha-amylase(Fardet et al.1999).Moreover,the physical barrier createdby the protein network limits the accessibility of starch toamylase and delays in vitro starch hydrolysis(Hoebler etal.1999).Various reports suggested that pasting character-istics(Wiesenborn et al.1994,Lai 2001),rheologicalproperties of paste and gels(Wiesenborn et al.1994,Kimet al.1995)and other functional properties(Wotton andBamunuarachchi 1978,Zobel 1984)of starches vary withspecies and variants.Gelatinization properties of starchesdepend on the type,granular structure,botanical originand amylose/amylopectin ratio(Sajilata et al.2006).Waxyand normal rice gelatinize between 60 and 78C(Thorburn et al.1987,Jenkins et al.1994).Many factorsaffect preference and acceptability of foods.Some factorsare intrinsic to the product,such as appearance,taste andflavour;other factors are extrinsic,such as social andFig.2 Parameters of the typicalrapid visco analyzer viscosityprofile for legumes blended riceextrudatesFig.1 Low cost collet extruderJ Food Sci Technolcultural factors(Deliza et al.1996).Keeping above pointsin view,the present work was undertaken to studyrheological and nutritional quality of selected dehulledlegumes blended rice extrudates.Materials and methodsDifferent dehulled legumes viz.black gram(Vigna mungo),green gram(Vigna radiata),lentil(Lens culinaris)and peas(Pisum sativum)and polished rice were purchased fromlocal market.After cleaning and grading,the raw materialswere coarse ground in plate mill to make grits in theparticle size range of 1.652.36 mm.Different legume gritswere blended at 0,5,10 and 15%levels with rice grits.Formaking extrudates,about 2 kg of blended materialsconditioned to 14%(wb)moisture were used.Low cost collet extruder It is a simple single screwautogenous extruder,driven by a 7.5 kW electric motor.The barrel length is 250 mm with a length to diameter ratioof 6:1 and has a central cylindrical die of 4 mm diam and5 mm length.The rotating speed of the screw is high(500 rpm)to allow high shear.The screw configuration hasconstant pitch and flight depth to allow a progressiveincrease in friction forces and temperature inside the barrel.The screw diam is 42.5 mm and the root diam is 32.5 mm(Fig.1).The moisture content was kept at 14%.Theextruder barrel wall has helical grooves to enhance frictionand cooking of the product.To ensure a regular feedingrate,the extruder is equipped with a motorised feedingscrew,but it was kept constant(25 kg/h)for this study.After extrusion,extrudates were ground(particle size 0.85 mm)and subjected for rheological and nutritionalanalysis.Rheological properties Pasting properties of extrudatepowders were determined using a Rapid Visco Analyser(RVA)Model 3-D(Newport Scientific Pvt.Ltd,Australia)with Thermocline software(3.0 version)by the Method No.162(ICC 1995).Sample suspension was prepared byplacing extrudate powder(3 g)in an aluminium canistercontaining(30 g)distilled water.A programmed heatingand cooling cycle was used.Each sample was stirred(960 rpm,10 s)while heated at 50C,and then constantshear rate(160 rpm)was maintained for the rest of theprocess.Temperature was held at 50C up to 1 min.Thenthe samples were heated(5095C,3 min 42 s)and held atTable 1 Parameters of viscosity profileTraitsabbreviationDescription(reference of terminology)PVPeak viscosity(61-02,Bao and Xia 1999)TTrough(61-02)BDBreakdown(Bao and Xia 1999,61-02),decreasein viscosity during cooking at 95CFVFinal paste viscosity at the end of final holdingperiod at 50C61-02 is the ICC(1995)methods010020030040050060070080002004006008001000Time(sec)Viscosity,cpvGreen gram010020030040050060070080002004006008001000Time(sec)Viscosity,cp010020030040050060070080002004006008001000Time(sec)Viscosity,cp0%5%10%15%Pea010020030040050060070080002004006008001000Time(sec)Viscosity,cpLentilFig.3 Typical rapid visco analyzer plot for different dehulled blended rice extrudatesJ Food Sci Technol95C for 2 min 30 s.Subsequently samples were cooleddown(95-50C,3 min 48 s)and then held at 50C for2 min.A RVA plot of viscosity(cP)versus time(s)wasused to determine peak viscosity(PV),trough(T),breakdown viscosity(BD)and final viscosity(FV)(Fig.2,Table 1).Each analysis was done in duplicate.Nutritional analysis Protein content(Kjeldahl method),fatand ash(Hart and Fischer 1971),and fibre(Sadasivam andManickam 1992)for different legumes blended riceextrudates were determined.Degree of gelatinization ofextrudates was done according to Wootton et al.(1971).Sensory evaluation A semi-trained panel consisting of 11members evaluated the extrudates.The sensory attributessuch as color,flavour,surface finish,taste,crispiness andover all acceptability of extrudates were evaluated using a9-point Hedonic scale(14 dislike extremely to slightly,5-neither like nor dislike,69 like to slightly extremely).Samples were served to panelists immediately after condi-tioning the extrudates(105C,3 min).Statistical analysis The data reported are mean of tenobservations and subjected to MS EXCEL 2000.Results and discussionEffect of low cost collet extruder on viscosity profile ofextrudates All viscosity parameters determined decreasedwith increased legume levels in blend as compared to riceextrudates alone(Fig.3).But the decrease was not muchpronounced in green gram based extrudate.The breakdownviscosity was maximum in peas whereas it varied in therange of 288297 cp and was lower in all the cases.Thefinal viscosity declined in all cases but the decrease wasmuch higher in green gram where it varied from 437 to 404cp.Similar observations were recorded for peak viscosityalso.When extrudates powder suspensions were heatedabove a certain temperature,water penetrated into thegranules and weakened the hydrogen bonds in starchsegments and reflected a degradative RVA profile ascompared to its corresponding raw material due tomechanical input.The viscosity increased during heatingat constant temperature(95C),continued to decreaseduring cooling and the profile finalized with a plateau fordifferent legumes and incorporation levels,but showed aslightly increasing trend at the end of the process.All theviscosity-temperature profiles of the studied systemsshowed a similar pattern.The maximum viscosity was151719212325272931051015Legumes incorporations levels,%Degree of gelatinization%Black gramGreen gramLentilPeasFig.4 Degree of gelatinization of different dehulled blended riceextrudatesLegumesLegumes,%Protein,%Fat,%Fibre,%Ash,%Black gram08.60.860.190.5659.20.900.250.62109.80.960.270.781510.51.030.290.96Green gram08.60.860.190.5659.70.900.240.741010.10.960.260.881510.91.020.280.98Lentil08.60.860.190.5659.70.900.230.661010.10.960.250.761511.21.030.270.88Peas08.60.860.190.5659.00.900.320.66109.60.960.390.781510.21.030.500.86Table 2 Nutritional analysis ofdifferent dehulled legumesblended rice extrudatesJ Food Sci Technolattained when the granules were in their most swollen state,still intact resulting in peak viscosity and this continuedheating of paste at this point,however,caused the granuleto rupture and accompanied by the fall in viscosity(Kearsley and Sicard 1989).The secondary increase inviscosity(setback)during the cooling phase which isassociated with the retrogradation phenomenon and relatedto amylose content was observed.Effect on degree of gelatinization Degree of gelatinizationfor rice extrudate was 29.4%.The degree of gelatinizationranged from 22.4 to 29.4%(Fig.4).The legumes blendedextrudates showed a lower degree of gelatinization com-pared to rice extrudates.Although there was no markeddifference in degree of gelatinization among the legumesblended extrudates,the black gram and green gram showedlower values(22.4%and 22.6%)followed by peas(23.3%)and lentil(23.2%)at 15%.Partial starch dextrinisation isdesirable because it reduces swelling during gruel prepara-tion,thus allowing an appropriate semi-fluid consistency tobe maintained at a higher concentration,i.e.higher energydensity.This signified that the extrusion cooking hasincreased the degree of gelatinization of the extrudates.According to Lin et al.(1997)fat content of extrudates wasshown to interfere significantly with starch gelatinization.Thus,decrease in gelatinization with legumes additioncould be due to the increased level of protein and fat ascompared to rice.Effect on nutritional value The rice(raw milled),blackgram,green gram,lentil and peas consist of 6.8,24,19.7,25.1 and 19.7%protein(Gopalan et al.1991).Thecombination of rice with legume forms a protein rich food.The legumes blended rice extrudates showed a proteincontent ranging from 8.6 to 11.15%(Table 2).Among theextrudates,rice extrudates showed low protein content ascompared to legumes blended extrudates.The proteincontent increased depending upon legume type.This maybe attributed to their inherent higher content of proteins inthe legumes.The lentil blended(15%)with rice extrudateshowed highest protein content.Extrudates made of ricealone and legumes blended rice extrudate showed a lowerfat percentage ranging from 0.86 to 1.03%as compared toraw rice(0.5%)and legumes viz.,black gram(1.4%),greengram(1.2%)lentil(0.7%)and peas(1.1%).There was nosignificant difference(p0.5)in fat content betweenlegumes except green gram,which showed a lower value(1.03).Fibre content of rice and legumes blended riceextrudate ranged from 0.19 to 0.50%.The fibre content ofextrudates showed an increasing trend with increase inlegume content because of the higher fibre content oflegumes than rice.Pea blended rice extrudates at higherlevel of blend showed higher fiber values.The ash contentof extrudates increased with increase of legumes levels.Ash content ranged from 0.56 to 0.98%.Black gram andgreen gram blended extrudates showed higher ash content(0.96%and 0.98%)followed by lentil(0.88%)and pea(0.86%).Effect on sensory attributes Sensory score was significantlyaffected by the blend levels in all the cases(Fig.5).However,black gram and pea blended extrudates did notshow much variation among overall acceptability ascompared to green gram and lentil based extrudates.Thecolour was affected by the blend levels of lentil and pea,which may be attributed to the inherent colour character-Black gram13579ColorFlavourSurface finishTasteCrispinessOver allacceptability Green gram13579ColorFlavourSurface finishTasteCrispinessOver allacceptabilityLentil13579ColorFlavourSurface finishTasteCrispinessOver allacceptabilityPeas13579ColorFlavourSurface finishTasteCrispinessOver allacceptability0%5%10%15%Fig.5 Hedonic scores of extru-dates made of different dehulledblended rice extrudatesJ Food Sci Technolistics of the legumes.However,the blend levels of blackgram(15%),peas(15%),green gram(10%)and lentil(10%)were found acceptable without altering the overallacceptability score as compared with rice extrudate alone.ConclusionThe low cost colletextruders with a small production capacitywill be suitable to process and produce legume blended riceexpanded snack foods and instant flour with low moisturecontent(14%,wb)and low lipid content.Extrudate flourswhich are partially dextrinised and gelatinized during thetreatment,yielding instant flour showed the scope forpreparation of higher energy density gruels.The lowerviscosity profile of extrudate flour as compared to its rawcomposite flour and higher nutritional and sensory 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