基于YJY-2型鮮葉分級機的機采茶葉分級分類工藝優(yōu)化

袁海波，滑金杰，鄧余良，江用文，王岳梁，陳根生，張?zhí)m美，尹軍峰※

（1.中國農(nóng)業(yè)科學(xué)院茶葉研究所，浙江省茶葉加工工程重點實驗室，國家茶產(chǎn)業(yè)工程技術(shù)研究中心，農(nóng)業(yè)部茶樹生物學(xué)與資源利用重點開放實驗室，杭州 310008；2.余姚姚江源茶葉茶機有限公司，余姚 315400；3.磐安縣農(nóng)業(yè)局特產(chǎn)站，磐安 322300）

基于YJY-2型鮮葉分級機的機采茶葉分級分類工藝優(yōu)化

袁海波1，滑金杰1，鄧余良1，江用文1，王岳梁2，陳根生1，張?zhí)m美3，尹軍峰1※

（1.中國農(nóng)業(yè)科學(xué)院茶葉研究所，浙江省茶葉加工工程重點實驗室，國家茶產(chǎn)業(yè)工程技術(shù)研究中心，農(nóng)業(yè)部茶樹生物學(xué)與資源利用重點開放實驗室，杭州 310008；2.余姚姚江源茶葉茶機有限公司，余姚 315400；3.磐安縣農(nóng)業(yè)局特產(chǎn)站，磐安 322300）

為解決機采鮮葉品質(zhì)等級參差不齊的問題，實現(xiàn)優(yōu)質(zhì)茶葉的機采機制，該文以新型鮮葉分級機為研究對象，比較了不同篩孔篩板組合、振動頻率等對機采鮮葉的分級效果，系統(tǒng)分析了分級鮮葉分類加工茶產(chǎn)品的感官品質(zhì)和綜合效益。試驗結(jié)果表明：鮮葉分級機的多塊篩板組合采用橢圓孔篩板（a=1.8 cm，b=2.2 cm）+圓孔篩板（D=2.0 cm）+圓孔篩板（D=2.6 cm）的方式較佳，能夠較好分離出碎片、一芽一葉、一芽二葉、一芽三葉及以上等不同嫩度級別的鮮葉；振動頻率采用50 HZ較為適宜，可獲得較佳的作業(yè)流暢性和分級效果，且篩板共振現(xiàn)象較??；分級葉所制產(chǎn)品的感官品質(zhì)與手采葉較為接近，較未分級樣有較大提升，綜合效益較機采葉直接加工每kg鮮葉可提高1.22元。

加工；機械化；農(nóng)業(yè)機械；鮮葉分級；篩板；振動頻率；效益

袁海波，滑金杰，鄧余良，江用文，王岳梁，陳根生，張?zhí)m美，尹軍峰.基于YJY-2型鮮葉分級機的機采茶葉分級分類工藝優(yōu)化[J].農(nóng)業(yè)工程學(xué)報，2016，32（6）：276-282.doi：10.11975/j.issn.1002-6819.2016.06.038 http://www.tcsae.org

Yuan Haibo,Hua Jinjie,Deng Yuliang,Jiang Yongwen,Wang Yueliang,Chen Gensheng,Zhang Lanmei,Yin Junfeng.Optimization of grading and classification technology for machine-picking leaves based on YJY-2 type classifier[J].Transactions of the Chinese Society of Agricultural Engineering(Transactions of the CSAE）,2016,32(6):276－282.(in Chinese with English abstract) doi：10.11975/j.issn.1002-6819.2016.06.038 http://www.tcsae.org

0 引言

近年來，在國家政策制約和消費市場推動的雙重引導(dǎo)作用下，具有品質(zhì)好、性價比高、消費領(lǐng)域廣等特點的優(yōu)質(zhì)茶逐漸成為茶產(chǎn)品市場的主體[1-3]。目前優(yōu)質(zhì)綠茶鮮葉原料的采摘與分級遭遇了關(guān)鍵的技術(shù)瓶頸[4-5]，就采摘而言，隨著采茶工短缺問題的加劇，人力成本不斷上升，當(dāng)前采摘工成本已占到了總生產(chǎn)成本的60%左右[6]；機械化采摘成為解決此難題的最可能途徑[7-9]，現(xiàn)有機采裝置中基于顏色、圖像等光電識別技術(shù)和機械手作業(yè)的選擇性智能采摘機尚處于實驗室階段，往復(fù)切割式采摘機仍是機采效率、成本、鮮葉品質(zhì)等綜合性能最佳的裝置[10-12]。

在采摘方式無法獲得實質(zhì)性突破的情況下，鮮葉的分級處理在所難免[13-15]，目前國內(nèi)已有多種分級裝置，如駱耀平[16]的MCF（自制滾篩）型名優(yōu)茶鮮葉原料分級機、楊擁軍[17]在傳統(tǒng)筒式分級機基礎(chǔ)上研制的螺旋導(dǎo)向茶葉鮮葉分級機、任廣鑫[18]等研發(fā)的大宗茶鮮葉原料分級機、翁炎生[19]設(shè)計的機采茶青篩選分級機、謝俊[20-21]等研制的基于三平移全解耦并聯(lián)機構(gòu)的茶葉篩分機等；筆者所在團隊亦成功研制出一種鮮葉篩分機（ZL200820169045.1）[22]。然而到目前為止，上述分級裝置大多處于實驗室或小試階段，大生產(chǎn)中應(yīng)用尚未可見。為此，本文以新研制的生產(chǎn)型鮮葉分級機（ZL201320064553.4）為突破口，從分級作業(yè)關(guān)鍵參數(shù)優(yōu)化、分類加工產(chǎn)品感官品質(zhì)和綜合效益比較等入手，系統(tǒng)開展優(yōu)質(zhì)茶機采葉分級分類加工技術(shù)的研究，以期為茶企提供具有較強實用性的新設(shè)備和技術(shù)參數(shù)，為真正解決“采茶難”困境提供技術(shù)支撐。

1 材料與方法

1.1 試驗原料和設(shè)備

1.1.1 試驗原料

以余姚姚江源茶葉茶機有限公司機采茶園為基地，采用便攜式名優(yōu)茶采摘機所采摘的龍井43品種鮮葉為試驗原料，手工采摘一芽一葉～一芽二葉嫩度鮮葉為對照。

1.1.2 分級設(shè)備

YJY-2型鮮葉分級機的整體結(jié)構(gòu)如圖1a所示，該設(shè)備采用篩分原理進行分級處理。設(shè)備關(guān)鍵性機構(gòu)為平面篩板，篩板上排布有不同孔徑的篩孔，越接近出葉端其孔徑越大，當(dāng)茶鮮葉在平面篩板上作規(guī)律性往前拋振運動時，借助鮮葉大小同篩板上篩孔直徑間的相關(guān)性，體積越小的鮮葉會越先通過篩孔掉落到底下，較大的鮮葉隨之在后面掉落，從而實現(xiàn)分級的目的。

1.1.3 檢測設(shè)備

SartoriusBT-124S型電子天平（德國），審評茶具，卷尺等。

1.2 研究方法

1.2.1 試驗設(shè)計

1）鮮葉分級機前后共可安裝4塊面積相同的篩板，鑒于本設(shè)備以獲得一芽一葉-一芽二葉嫩度鮮葉為主要目的，中間篩板的分級處理最為重要，故將中間2塊篩板的孔徑設(shè)為相同；分級作業(yè)時，機采葉經(jīng)過第1塊篩板，單芽或小碎片從篩板的篩孔中掉落，由下方出葉口1收集，從而被分離出來；經(jīng)過中間兩塊篩板時一芽一葉-一芽二葉嫩度的鮮葉從該篩板的篩孔掉落，由出葉口2收集分離出來，最后一塊篩板將一芽三葉嫩度鮮葉通過出葉口3分離出來，更粗老的鮮葉則因無法從篩板孔徑掉落而直接從最終出料口滑出；根據(jù)中小葉品種一芽一葉、一芽二葉的長寬大小，分別設(shè)計以下不同孔徑和孔型篩板處理（見表1）。

圖1 YJY-2型鮮葉分級機結(jié)構(gòu)示意圖和實物圖Fig.1 Physical and structure diagram of YJY-2 type leaf grading equipment

表1 鮮葉分級機不同篩板組合Table 1 Experimental treatment with sieve plate of leaf classifier machine

2）振動頻率設(shè)置：通過控制旋鈕調(diào)節(jié)變頻器的功率來設(shè)置不同振動頻率，設(shè)定為40、50、60 Hz 3檔。

1.2.2 加工工藝

分別將手采葉（采摘嫩度為一芽一葉～一芽二葉）、機采葉及機采葉分級處理樣加工成曲毫形綠茶，加工工藝流程為：鮮葉攤放→殺青→攤涼→揉捻→初烘→攤涼回潮→炒小鍋→攤涼→炒大鍋→烘至足干

1.2.3 評審方法

按GB/T 23773-2009的取樣方法[23]，取3 g茶樣，加入150 mL沸水沖泡5 min后進行密碼評審。評定外形色澤、湯色、香氣、滋味，每項滿分100分，總分采用加權(quán)法，品質(zhì)總分＝外形色澤×0.20+湯色×0.20+香氣×0.25+滋味×0.25+葉底×0.10。

2 結(jié)果與分析

2.1 不同孔型孔徑篩板分級比較

筆者所在課題組前期研究顯示，龍井43品種因具有發(fā)芽整齊度高、枝條粗細均勻性好、枝葉著生角度較大等特點而利于機械化采摘。龍井43機采葉分級處理結(jié)果如表2所示，相比未分級機采鮮葉，采用4種組合均可實現(xiàn)不同嫩度等級鮮葉的篩分分級，4種組合處理出葉口1分級葉中單片、碎片比例為72.04%～75.95%，平均值較未分級高53.80%，出葉口2分級葉中單芽～一芽一葉比例為66.24%～70.44%，平均值較分級前高42.53%，出葉口3分級葉中一芽二葉比例為62.32%～68.40%，平均值較分級前高39.07%，出葉口4分級葉中一芽三葉以上比例為73.03%～81.55%，平均值較分級前高49.95%。

篩板1孔徑最小，其目的在于去除碎片和個體較小的單片，不同篩孔篩板1的分級效果如圖2所示。從圖中可以看出，2種不同篩孔的篩板具有較好的篩分碎片和單片的效果，但兩者間分級效果差異明顯（α=0.05），其中以橢圓孔（a=0.6 cm，b=2.0 cm）篩板要顯著好于圓孔（D=0.6cm）篩板，推測可能與橢圓孔篩板的長軸面更利于部分單片通過有關(guān)。單芽～一芽一葉的組成比例在兩種篩板間也呈顯著性差異（α=0.05），且為圓孔篩板好于橢圓孔篩板，但因其組成在整體中的比例較低，故不將其作為篩板篩選評判因子。

中間2塊篩板是分級作業(yè)獲得目標性鮮葉組分的關(guān)鍵。圖3顯示，此部分篩板在篩分單芽～一芽一葉組分時以圓孔（D=2.0 cm）要好于橢圓孔（a=1.8 cm，b=2.2 cm），兩者間呈顯著性差異（α=0.05）。根據(jù)試驗結(jié)果推測，與單片的平面式分布相比，單芽和一芽一葉一般呈立體式分布，能否通過篩板主要由鮮葉和篩孔的整體長度和直徑共同決定，孔型在此階段的影響相對較弱。

一芽二葉嫩度的鮮葉是制作優(yōu)質(zhì)茶葉的理想原料，篩板3的主要目的即為在前段分級的基礎(chǔ)上盡可能篩分出此嫩度的鮮葉原料。從圖4可以看出，篩板3分級處理葉中一芽二葉嫩度鮮葉的比例平均為65.63%，可以實現(xiàn)較好分離；兩種篩孔比較以圓孔（D=2.6 cm）要好于橢圓孔（a=2.4 cm，b=2.8 cm），且兩者間差異顯著（α= 0.05）。一芽三葉嫩度分級葉則以橢圓孔顯著好于圓孔，推測與橢圓孔篩板的長軸有關(guān)，但其組成在整體中的比例相對較低。

從上述試驗結(jié)果可知，不同篩孔篩板組合以篩板1采用橢圓孔（a=1.8cm，b=2.2cm）、篩板2采用圓孔（D=2.0cm）、篩板3采用圓孔（D=2.6cm）為好，利于不同篩分階段獲得最佳的分級效果；圖5為出葉口4的分級鮮葉的機械組成，分析可知，此部分分級葉以一芽三葉及其以上嫩度為主，其在組合1、組合3中所占比例顯著高于組合2和組合4，其中又以組合3稍好于組合1。由于用于分級的鮮葉的機械組成一致，因此此結(jié)果亦可證明前段分級所用篩板組合較佳。

表2 不同孔型孔徑篩板分級效果比較Table 2 Comparison of classification effect with different pass aperture sieve plate(%)

圖2 不同篩孔篩板1的分級效果比較Fig.2 Comparison of classification effect with different pass aperture sieve plate 1

圖3 不同篩孔篩板2的分級效果比較Fig.3 Comparison of classification effect with different pass aperture sieve plate 2

圖4 不同篩孔篩板3的分級效果比較Fig.4 Comparison of classification effect with different pass aperture sieve plate 3

圖5 出葉口4的分級葉機械組成Fig.5 Mechanical composition of graded leaves by discharging port 4

表3 3種振動頻率作業(yè)效果比較Table 3 Comparison of three kinds of vibration frequency operation

2.2 不同振動頻率分級比較

YJY-2型鮮葉分級機通過篩板的前后往復(fù)振動，使得鮮葉在篩板上呈現(xiàn)向前上方拋振的運動軌跡，不同的振動頻率不僅會影響鮮葉分級效果，而且會影響分級作業(yè)工效。圖6、表3是3種振動頻率下每個出葉口優(yōu)勢組成和作業(yè)效果的比較結(jié)果。從圖表中可以看出，3種頻率下每個出葉口優(yōu)勢組成比例差異不大，僅一芽三葉以上嫩度處理存在顯著差異，以50 Hz分級樣的比例顯著高于40 Hz處理。分級作業(yè)時當(dāng)振動頻率較低，鮮葉在篩板上“流動”較慢，易出現(xiàn)篩板“掛葉”現(xiàn)象，不僅影響分級作業(yè)效率，而且因“掛葉”堵住篩孔導(dǎo)致分級效果減弱；振動頻率過高，雖然作業(yè)效率高，流暢性好，但因鮮葉“流動”速率快，會使部分鮮葉來不及從篩孔掉落而又被拋振出去，同樣降低分級效果；同時，振動頻率高容易形成篩板共振，造成凸輪軸承的斷裂。從本試驗結(jié)果看，振動頻率選用50 Hz較為適宜。

圖6 3種振動頻率下每個出葉口優(yōu)勢機械組成比較結(jié)果Fig.6 Comparison of dominant mechanical components of each outlet with three kinds of vibration frequency

2.3 分級分類加工成品茶感官品質(zhì)比較

不同鮮葉所制成品茶的感官審評結(jié)果如表4所示。其中分級茶樣1為分級出葉口2和出葉口3混合鮮葉所制，分級茶樣2為出葉口4鮮葉所制。從表中可以看出，機采葉分級處理后所制產(chǎn)品的外形、香氣、滋味等感官品質(zhì)較未分級樣有較大幅度提升，平均感官得分提高了2.55，且尤其體現(xiàn)在風(fēng)味內(nèi)質(zhì)上。與手采樣相比，分級茶樣1在外觀、內(nèi)質(zhì)等方面均較為接近，分級茶樣2因主體鮮葉嫩度稍差，在外形、葉底等品質(zhì)評分中存在差距，但香氣、滋味等內(nèi)在品質(zhì)則差異較小。

表4 不同處理成品茶感官審評比較Table 4 Comparison of sensory evaluation of different processed products

2.4 分級分類加工效益分析

機采葉分級分類加工綜合效益分析如表5所示。本試驗中機采葉經(jīng)分級處理后再進行分類加工，成品茶產(chǎn)量較未分級樣提高了18.1%，平均制得率提升了2.74%，其原因在于機采葉大小不一，不分級直接加工容易在殺青、揉捻、曲毫做形等工序產(chǎn)生較多碎末，從而降低制得率；未分級處理下腳料較分級分類加工多9.2kg亦可證明此推測。從效益情況分析可以看出，分級作業(yè)雖然多出了人員費用和電費，但因分類加工茶產(chǎn)品的品質(zhì)、售價和制得率的提升，其綜合效益較未分級多出了489.8元，即每kg鮮葉可提高效益1.22元。

表5 機采葉分級分類加工經(jīng)濟效益分析表Table 5 Economic benefit analysis of the classification and processing of the machine

3 結(jié)論與討論

1）生產(chǎn)型鮮葉分級機同一位置不同孔型孔徑的選擇主要從篩孔面積、篩板承受力及形成共振等方面綜合考慮，單個篩孔面積大則鮮葉掉落的概率就大，但孔數(shù)就少，且易形成共振對篩板造成損傷。不同篩孔比較結(jié)果分析表明，篩板1采用橢圓孔（a=0.6 cm，b=2.0 cm）篩板較好，可以更好的分級出單片、碎片等細小型或長軸型的鮮葉；篩板2主要用于分級獲得一芽一葉嫩度為主的鮮葉，其適宜的篩孔為圓孔（D=2.0 cm）；篩板3采用圓孔（D=2.6 cm）較好，有利于分級獲得一芽二葉嫩度為主的鮮葉，且通過上述篩板組合的應(yīng)用，最后出口的分級鮮葉則以一芽三葉及以上嫩度為主。

2）振動頻率的選擇主要由篩板所用材料和分級效果而定，不同頻率比較結(jié)果分析表明，生產(chǎn)型鮮葉分級機的振動頻率選用50Hz較為適宜，即可以獲得較佳的流暢性和分級效果，同時篩板共振現(xiàn)象較小，避免了對篩板的損傷。

3）機采葉分級分類加工產(chǎn)品品質(zhì)和效益分析表明，分級葉所制產(chǎn)品的感官品質(zhì)較未分級樣有較大提升，與手采鮮葉所制茶樣相比，分級茶樣1在外觀、香氣、滋味等方面均較為接近；本試驗中，機采鮮葉經(jīng)分級處理后分類加工成卷曲型綠茶，其綜合效益較機采葉直接加工每kg鮮葉可提高1.22元。

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Optimization of grading and classification technology for machine-picking leaves based on YJY-2 type classifier

Yuan Haibo1,Hua Jinjie1,Deng Yuliang1,Jiang Yongwen1,Wang Yueliang2,Chen Gensheng1, Zhang Lanmei3,Yin Junfeng1※
(1.Tea Research Institute,Chinese Academy of Agricultural Sciences;Key Laboratory of Tea Processing Engineering of Zhejiang Province; National Engineering Technology Research Center of Tea Industry;Key Laboratory of Tea Biology and Resources Utilization Ministry of Agriculture,Hangzhou 310008,China;2.The Yuyao Yao-Jiang-Yuan Tea and Tea Machine Co.Ltd,Yuyao 315400,China;3.Panan County Bureau of Local Products,Panan 322300,China)

The mechanized picking of fresh tea leaves gains the advantages of high efficiency,low cost and laborsaving, which is favorable to large-scaled and mechanized tea production in the future.However,due to the limitations of existing picking equipment,machine-picked fresh leaves are often the mixtures of old and tender leaves with different grades,which seriously affects the sensory quality and economic benefits of tea products.Therefore,the classification of collected fresh leaves is required before processing.In order to avoid uneven quality of fresh leaves and thereby achieve mechanized plucking and processing for high quality tea leaves,the working settings of a novel fresh leaves classifier(ZL 201320064553.4)were systematically investigated in this study.Using mechanically plucked fresh leaves of Longjing 43 tea variety as experimental material,we compared the classification efficiency using different combinations of grading sieve plates(i.e.,a variety of hole types such as round and ellipse holes)and vibration frequency(40,50 and 60 Hz).We applied the tea processing workflow including spreading out fresh leaves,fixation,cooling,rolling,initial baking,cooling resurgence,first frying,cooling,second frying,and baking sufficiently.Hand-picked leaves(tenderness from one bud with one leaf to one bud with 2 leaves),mechanically picked leaves and mechanically picked leaves with classification were processed to the coiled type green teas,respectively according to the steps described above.Then we systematically evaluated the sensory quality and comprehensive benefit of obtained tea products.The results showed that when the novel fresh leaves classifier was applied to classify the mechanically plucked fresh leaves of Longjing 43 tea variety,the sieve plate#1 with ellipse holes(the length of the short axis was 0.6cm,and the length of the long axis was 2.0 cm)resulted in better grading for small or elongated fresh leaves such as one leaf and debris,and the average proportion of such fresh leaves in the outlet was 75.7%.The sieve plate#2 with round holes(the diameter was 2.0 cm)was suitable for the classification of the fresh leavesthat were“one bud with one leaf”(one of the target products of grading operation),and the average proportion of this kind of fresh leaves in the outlet was 70.22%.The sieve plate#3 with round hole(the diameter was 2.6 cm)was suitable to classify the fresh leaves that were“one bud with 2 leaves”(one of the target products of grading operation),and the average ratio of such leaves in the outlet was 67.89%.Moreover,by combination of these sieve plates,the finally obtained fresh leaves after grading showed the tenderness predominantly equal to or higher than“one bud with 3 leaves”,and the average percentage of this kind of fresh leaves in the outlet was 79.53%.The selection of vibration frequency was dependent on the plate material and classification effect.When the vibration frequency was low,it not only affected the operation efficiency of classification,but also weakened the effect of grading since the hanging leaf would block the meshes.When the vibration frequency was too high,despite good fluency,the“flow”rate of fresh leaves was so high that some of the fresh leaves would be thrown out,resulting in classification efficiency reduction.Furthermore,the high vibration frequency was more likely to form plate resonance and break the cam bearing.So a vibration frequency of 50 Hz was appropriate to achieve the satisfactory grading and smooth operation with less resonance,and thus avoid the damage to sieve plates.Sensory evaluation results showed that the tea products made from the graded leaves had significantly improved sensory quality compared with those without classification,and the average sensory score was improved by 2.55,especially in the flavor.Compared with the products made from hand-picked leaves,the tea sample of Grade 1 was similar in appearance,aroma and taste.In this study,by machine-grading of fresh leaves and processing into coiled type green tea,the finished tea production was increased by 18.1%,and the average yield was increased by 2.74%;in addition,the comprehensive profit was remarkably improved by 1.22 yuan per kg fresh leaves,compared with that obtained by direct processing of machine-picked leaves without grading.

processing;mechanization;agricultural machinery;classification;sieve plate;vibration frequency;efficiency

10.11975/j.issn.1002-6819.2016.06.038

TS255.35

A

1002-6819（2016）-06-0276-07

2015-08-12

2016-01-29

中國農(nóng)業(yè)科學(xué)院科技創(chuàng)新工程（CAAS-ASTIP-TRICAAS）、浙江省“十二五”農(nóng)業(yè)重大成果轉(zhuǎn)化工程（2012T202-03）

袁海波，男，漢族，江蘇江陰人，主要從事茶葉加工與茶飲料工程研究。杭州 中國農(nóng)業(yè)科學(xué)院茶葉研究所，310008。

※通信作者：尹軍峰，男，漢族，浙江桐廬人，主要從事茶及茶飲料加工工程技術(shù)研究。杭州 中國農(nóng)業(yè)科學(xué)院茶葉研究所，310008。

Email:yinjf@mail.tricaas.com