Nghiên cứu công nghệ và thiết bị sấy long nhãn

KET QUA NGHIEN CUU KH CN CUA VIEN CONG NGHE SAU THU HOACH NAM 2001 NGHIEN CUU CONG NGHE VA THIET BI SAY LONG NHAN Cao Van Himg, Dang Xuan Mai, Biii Kim Khanh, Nguydn Thi Tii Quynh, Nguydn Thj Thu Trang, Dang Thi Thanh Quyen Be} mdn Bdo ipidn - Vien Cdng nghe sau thu hoach May say long nhan ban co gieti true dirng quay SN-300 cdng suai 70kg/me dupe thiei ke phii hetp vdi qui mo hp gia dinh Qua cac thi nghiem da xac dinh qui trmh say va xay dung dupe mo himh say nhu sau: Vdi long let cd hai qua trinh say .Say d nhiel dp 60"C tdi ham dm qua de' boc vd va hat la 40% vdi teic dp beic hoi aim la 1,02%/h, sau dd dem ciii sau say di xdng hoi luu huynh lieu luimg gam/0,.353m' 40 phut rdi lien hanh say cung d 60"C cho de'n kho (35-37%) se cd long let chai lupng tdt nhai Vdi long xoay cung co hai qua trinh say Say d nhiet dc) 120"C, say den ham dm cui 70% (trong khoang 30-35 phut) rdi chuydn sang sa'y d 50-60"C cho den khd (35-37%) vcii tdc dp bdc hoi dm la 32% dm/h (ddi vdi say 1) va 2,693,18% ain/h (ddi vdi say 2) se cho chai lupng long nhan xoay loi nhai Chai lupng long nhan xoay dat duetc dc:p ve trang thai, hinh dang, mau sSc, hirong vi va dam bao ve sinh an loan thuc pham Cong nghe say long nhan vcii thiei bi say SN300 da dupe trien khai va ap dung cho kei qua tdi LDATVANDE ''^r Say nhan la bien phap quan trpng chd bidn, bao quan va tieu thu nhan hien Cd loai long nhan (theo each gpi truydn thdng): long ttit, bach long va long xoay Hien khdi lupng nhan say chiem 55-60% teing luctng nhan tuoi Viii nam gdn day md rpng quan he buPn ban vdi Trung qudc nen thj trudng nhan say khd da duoc hinh thanh, sd luemg san pham dang cang lang Udc tinh tai Hung Yen cd khoang 600 Id say thu cdng vdi nang suai 0,5-1,5 tan nhan tuoi/ld, Nhung Id say da mang lai ngudn thu dang kd cho ngudi ddu tu ma cdn gdp phan vao binh dn gia nhan phia Nam, viec say nhan khdng manh me nhu phia Bdc, nhan sir dung de say chii ye'u tai cac vimg trdng nhan long bdng cac Id sa'y thu cdng nen chat lupng san phdm khPng cao, cPng nghe say d mdi dja phuong mpt khae thieu ky thuat hoac thPng tin can thiet nen ban chd chai lupng va su dn djnh chai lucmg Da ed mpt vai chuydn giao ePng nghe giira nPng dan vdi ndng dan tir mien bdc de'n mien trung nudc ta nhung thie'u ddng bp nen vdn chua dat yeu cdu mong mudn Mat khac Id say thu cdng la khong ban che dupe tinh dn djnh cap nhiet, vdn dang sir dung khdi Id lam tac nhan say nen chat lupng san phdm khdng dam bao ve sinh an toan thuc phdm, rai cdn thiet nghien cuu de sir dung tac nhan say la khdng khd, ndng dd khdc phuc cac tdn tai tren Theo thu thap nhidu ngudn thdng tin ngoai nudc thdi gian dai thi tren the gidi chua cd cae nghien ciiru vd cdng nghe va thidt bj say long nhan hoac chua phd bie'n nen rai thie'u nhirng thdng tin lam eo sd cho nghien curu Nhung can cir vao eae ky thuat truyen thdng cd dien nudc ta ciing cac nghe; nhan truydn thd'ng linh vuc nay, chiing tdi tie'n hanh nghien ciiu cdng nghe va thidt bj say nhdm dat dupe qui trinh cPng nghe hoan chinh de dat dupe eae muc tieu sau; 334 Nang cao chat lupng san phdm vd cam quan nhu trang thai, hinh dang, mau sdc dac trung eua long nhan xoay nhdm nang eao gia trj va gia trj sit dung long nhan Dam bao ve sinh an loan thuc phdm cua san pham Giam thidu P nhidm mPi trudng khdi bui ndng gay qua trinh say bdng Id thii cdng tai cac lang nghd say Tao md binh thiet bj say phii hpp ban co gidi qui mP hp gia dinh II VAT LIEU VA PHUONG PHAP - Tir thi nghem nhd den thi nghiem Idn phdng thi nghiem - Tir thi nghiem ldn den thuc nghiem nhd tai hien trudng - Tii thue nghiem nhd de'n trinh didn Idn tai cac co sd san xuat de danh gia ket qua va kha nang ap dung - Ket hpp nghien cihi vdi viec xay dung md hinh san xuat va chuyen giao tien bp ky thuat cho san xuat tai hp nPng dan - Sir dung phuong phap Tbi nghiem ye'u td va thidt ke thi nghiem ngdu nhien hoan toan - Tinh trung binh tdng the - Do lech tieu chuan tdng thd (dp lech mdu) - Cae chi tieu phan tich chat lupng san phdm theo cac lieu chudn hien hanh - Nguyen lieu nhan; Vu nhan nam 2000 vdi cac gidng nhan mien Trung va mien Bdc dupe thu thap tir cac chp d Ha Npi va tai vudn nhan tinh Hung Yen III KET QUA VA THAO LUAN 3.1 Long tet Long tet dupe tao bdi say ca qua nhan (qua cdn vd, ciii, hat) dcii dci dm nhai dinh sau dd tach vd, hat rdi lay ciii say ticp den khd Cdi t Nhan qua — • Say I —•Tach vd, hat — • Xir ly — • Sa'y2 — • Long let Vd, hat 3.1.1 Anh hudng ciia nhiet dp say qua den chat lupng ciii sau say (long tet) Chat lupng ciii sau say dupe bieu thj (Tinh theo thir tu uu tien) nhu sau: - Trgng thdi: Trang thai ciii nguyen den den ciii nat irng vdi didm tir den - Mail sdc: Mau tir vang sang den iniiu den irng ve'ti dicm lir don - Tinh cd the chdp nhdn dugc: Chap nhan dupe den khong chap nhan dupe irng vdi diem tir de'n I Nhan qua dupe phan loai bd cudng, lam sach sau dd dem say Say dupe lien hanh d cac nhiet dp say khac 50, 60, 70, 80±rC irng vdi cac thdi gian khac dd cho qua khd den mpt ham dm nhai djnh la 44±1% rdi lien hanh bdc ciii Danh gia chat luctng ciii theo cac tieu chudn tren Ket qua la; Khi nhiel dp say tang, chat luong ciii say giam Trong khoang nhict dp say 50-60"C, chai lucmg ciii say hdu nhu gid'ng d ca ba chi lieu chat lucmg la trang thai, mdu 335 sdc va tinh cd the chap nhan dupe va dat sd didm chat lucmg cao nhat Cha't lupng ciii sau sa'y den ham dm qua 44± % (Long tet) la tdt nhdt say d nhiet dp 50-60"C 3.1.2 Anh hudng ciia ham am qua de boc cui den chat lupng cui sau say (long tet) Cac mdu chudn bi thi nghiem dupe thuc hien gid'ng nhu muc 3.3.1 Nhan qua dupe say d nhiet dp 60"±l"C tdi cac ham am 37, 40, 45, 50, 55, 60, 65±I%) rdi tien hanh bdc ciii Danh gia chat luemg ciii theo cac tieu chudn tren Ket qua la: (That lugng cui sau sdy I nhiet dp say 60"C (Long tet) la tdi nhai say den ham am qua dd bdc cui la 40±I% 3.1.3 Anh hucmg ciia tdc dp bay hoi am den chat lupng cui sau saiy (long tet) Tdc dp bay hoi am bieu thj dp giam am eua nhan qua (%) theo thdi gian (gid) Cac mdu thf nghiem dupe chudn bj nhu muc 3.1.1 Nhan qua dupe say d eae nhiet dp 50, 60, 70, 80+I"C den ham dm qua la 40, 45, 50, 55, 60, 65±1% d cac td'c dp bay hoi dm khac ma bieu thj gian tiep qua thdi gian say 20, 25, 30, 35, 40, 45h Ket qua cho thay chat lupng eiii sau say I d eac nhiet dp say va ham am qua khac (long let) la tdt nhdt say vdi tdc dp bay hoi am la 0,92-1,15%/h 3.1.4 Anh hudmg cua cac chat xir ly den chat lupng cui sau saiy (long tet) Nhan qua dupe chudn bj nhu muc 3.3.1 Nhan sau say (nhiet dp say; 60"C, ham dm qua de bdc ciii: 40%, tdc bay hoi am; 1,02%/h) dupe dem di bdc ciii Sir dung cui bdc dupe dem tien « '!j * hanh xir ly nhu sau rdi dem di say Cdch tien hanh xif ly: •' :- ,i; Nhiing ciii dung djch Na,HS04 Ig/I; 2g/l; 3g/I phut, de rao rdi dem sdy XPng ciii bdng hoi SO, (Ig; 2g; 3g S) 40 phut rdi dem say Rira ciii bang nudc 100"C; 50"C; nudc thudng 2-3 phiit, de rao rdi dem say .Say dupe tidn hanh d nhiet dp 60"C thdi gian dii dd de'n khd, cdng doan say dua trcn ket qua say ve cac thdng sd nhiet dp va chai lucmg long tet chii ydu phu thupc quyet djnh viio say I nen say chi dieu chinh et nhiet dc) say la cd kha nang bay hcti dm cho de'n khd Kcl qua cho thay chat lupng ciii sau say lii tdt nhai ciii nhan sau say ductc xir ly bdng each xdng ciii bang hoi SO, (2g S/0,352m-') 40 phiit rdi dem say 3.1.5 Cdng nghe say long tet Tir cac kdl qua nghien curu anh huetng ciia nhiet dp say (±1"C), ham dm qua klii bdc ciii (±1%) va tetc dp bay heti dm (ii),0/%>am/h) qua trinh say ddn chdt lupng long let Di tai da xac djnh dupe dudng cong say va dudng cong nhiel dp say nhu sau (hinh I va 2):