Nghiên cứu chế biến sản phẩm puree và bột từ trái lêkima

Danh sach bang Noi dung Trang Bang 1: Thanh phan dinh duong cua trai lekima trong lOOg 3 Bang 2: Mot so tinh chat cua maltodextrin 8 Bang 3: Tieu chuan chat luong cua maltodextrin dang

TRUOflNG DAI HOC AN GIANG KHOA NONG NGHIEP & TAI NGUYEN THIEN NHIEN

BO MON CONG NGHE THlTC PHAM

HUYNH THI NGOC NGUYEN

N G H I E N CUtJ C H E B I E N SAN P H A M P U R E E V A B O T TlT

T R A I L E K I M A

BAO CAO KHOA LUAN T O T NGHIEP DAI HOC

TRUONG DAI HOC

AN GIANG

THtf V I E N

Nganh hoc: Cong Nghe Thirc Phirn

Can bo hirong dan: ThS Trhn Xuan Hiln

KHOA HOC: 2009 - 2013

An Giang, Thang 4 2013

T R I C I N G DAI HOC AN GIANG KHOA NONG NGHIEP & TAI NGUYEN T H I E N NHIEN

BO MON CONG NGHE THlTC PHAM

N G H I E N CUtJ C H E B I E N SAN P H A M P U R E E V A B O T TlT

T R A l L E K I M A

Do sinh vien: HUYNH THI NGOC NGUYEN thirc hien va de nap

Kinh trinh hoi dong cham khoa luan tot nghiep xet duyet

Long Xuyen, ngay 22 thdng 4 nam 2013

CAN BO HUONG DAN

ThS Tran Xuan Hien

Loi cam ta

De thirc hien va hoan thanh dirge de tai khoa luan tot nghiep nay, toi xin dugc guri lai

cam an chan thanh va sau sac den:

Thac sy Tran Xuan Hien, Truong Bp mon Cong Nghe Thirc Pham dong thai cung la giao vien huong dan da tan tinh truyen dat va chi day toi trong suot qua trinh hgc tap trong 4 nam qua cung nhir huong dan toi thirc hien khoa luan tot nghiep dai hgc

Quy Thay Co Bg mon Cong Nghe Thirc Pham, Truong Dai hgc An Giang da nhiet tinh giang day va truyen dat trong suot qua trinh hgc tap cua toi vira qua

Co Nguyen Thi Nggc Giang (can bo phong thi nghiem) ciing cac can bo nhan vien phong thi nghiem truong Dai hgc An Giang da tao mgi dieu kien thuan lgi va quan tarn giiip do toi trong suot qua trinh thirc tap de thirc hien va hoan thanh de tai nay Cac ban sinh vien lop DH10TP da ho trg va co nhieu dong gop bo ich giup toi thuc hien tot de tai tot nghiep nay

Xin tran trong cam on !

Long xuyen ngay 22 thdng 4 nam 2013

Sinh vien thuc hien

Huynh Thj Ngoc Nguyen

Muc luc

Noi dung Trang

Lai cam ta i Muc luc ii Danh sach bang iv

Danh sach hinh v

Tom luoc vi

Chirong 1 Gioi thieu

1.1 Dat van de

1.2 Muc tieu nghien cuu

1.3 Noi dung nghien cuu

Chirong 2 Liroc khao tai lieu 2

2.1 Tong quan ve nguyen lieu 2

2.1.1 Lekima 2 2.1.2 Sic t6 carotenoid va p- carotenoid 4

2.1.3 Acid citric 6

2.1.4 Vitamin C 6

2.2 Maltodextrin 8

2.3 Cac qua trinh, nguyen ly che bien va bao quan co lien quan 9

2.3.1 Qua trinh rua 9

2.3.2 Qua trinh boc vo 9

2.3.3 Qua trinh thanh trung 9

2.3.4 Qua trinh siy 11

2.4 Cac nghien cuu trubc day (trong va ngoai nuoc) 15

Chirong 3: Phirong tien va phirong phap nghien cihi 17

3.1 Phuong tien nghien cuu 17

3.1.1 Dia diem va thcri gian nghien cuu 17

3.1.2 Nguyen vat lieu, thiet bi can cho thi nghiem 17

3.2 Phuong phap nghien cuu 17

3.3 Qui trinh nghien cuu dir kien 19

n

3.3.1 Qui trinh san xuat puree le ki ma 19

3.3.2 Quy trinh san xuat bot le ki ma 19

3.4 Thuyet minh quy trinh 20

3.4.1 Qui trinh san xuat puree le ki ma 20

3.4.2 Quy trinh san xu4t bot le ki ma 20

3.5 Noi dung nghien cuu 20

3.5.1 TNI: Khao sat cac ySu to anh huong den chat luong san pham puree lekima 20

3.5.2 TN2: Khao sat cac yeu to anh huong den chat luong san pham bot lekima 23

Chinmg 4:Ket qua va thao luan 26

4.1 Thanh phan hoa hoc ciia trai lekima 26

4.2 Anh hudng ciia pH va nhiet do thanh thing den chat luong san pham

pure lekima 26 4.2.1 Anh hudng ciia pH den chat luong pure lekima 26

4.2.2 Anh hudng ciia nhiet do thanh thing den chat luong pure lekima 27

4.3 Anh hudng ciia bao bi den sir thay doi chat luong san pham pure lekima 29

4.4 Anh hudng ciia ti le maltodextrin va nhiet do say den chat luong san pham 32

4.5 Anh hudng cua bao bi den sir thay doi chat luong san pham 36

Chirong 5: Ket luan va de nghi 41

Danh sach bang

Noi dung Trang

Bang 1: Thanh phan dinh duong cua trai lekima trong lOOg 3

Bang 2: Mot so tinh chat cua maltodextrin 8

Bang 3: Tieu chuan chat luong cua maltodextrin dang bot 9

Bang 4: Bang cac phuong phap danh gia cam quan 18

Bang 5: Thang diem Hedonic 18

Bang 6: Thanh phan hoa hoc cua lekima tinh tren % thit qua 26

Bang 7: Ket qua thong ke anh hudng cua pH den chat luong san pham 26

Bang 8: Ket qua thong ke anh hudng ciia nhiet do thanh trung den mau sac va ham

luong p-carotene ciia san pham 27

Bang 9: K6t qua thong ke anh hudng ciia pH va nhiet do thanh trung den cac

chi tieu ciia san pham pure lekima 28

Bang 10: Ket qua thong ke anh hudng ciia bao bi den cac chi tieu ciia

san pham sau 3 tuan bao quan 29

Bang 11: Ket qua thong ke anh hudng ciia ti le maltodextrin den cac chi tieu

ciia san pham 32

Bang 12: Ket qua thong ke anh hudng ciia nhiet do say den cac chi tieu

ciia san pham 32

Bang 13: Ket qua thong ke anh hudng ciia ti le maltodextrin va nhiet do say

den chat luong san pham 33

Bang 14: Ket qua danh gia cam quan san pham theo nhiet do 35

Bang 15: Danh muc cac chi tieu cam quan va he so quan trong tuong ung

ciia san pham purree 37

Bang 16: Danh gia chat luong san pham theo Tieu chuan Viet Nam (TCVN 3215-79) 37

Bang 17: Danh muc cac chi tieu cam quan va he so quan trong tuong ung

ciia san pham bot rau qua 38

Bang 18: Danh gia chat luong san pham bot lekima theo TCVN 3215-79 38

Bang 19: Thanh phan hoa hoc ciia san pham puree lekima 39

Bang 20: Thanh phan hoa hoc ciia san pham bot lekima 40

Danh sach hinh

Noi dung Trang

Hinh 1: Trai lekima chin 2

Hinh 2: Cong thuc cau tao P- carotene 5

Hinh 3: Quy trinh san xuat puree lekima 19

Hinh 4: Quy trinh san xuat bot le ki ma 19

Hinh 5: So do bo tri thi nghiem 1 21

Hinh 6: So do bo tri thi nghiem 2 22

Hinh 7: So do bo tri thi nghiem 3 23

Hinh 8: So d<5 bd tri thi nghiem 4 24

Hinh 9: Do thi the hien P-carotene thay doi theo thoi gian bao quan va bao bi 30

Hinh 10: Do thi thS hien gia tri b thay doi theo thoi gian bao quan va bao bi 30

Hinh 11: D6 thi th<§ hien AE thay doi theo thoi gian bao quan va bao bi 30

Hinh 12: Do thi the hien sir thay doi muc do ua thich theo thoi gian

bao quan va bao bi 31

Hinh 13: Puree sau 2 tuan bao quan 31

Hinh 14: Puree sau 3 tuan bao quan 31

Hinh 15: Ham luong p-carotene ciia san pham d cac ti le maltodextrin

va nhiet do say khac nhau 34

Hinh 16: Bieu do the hien sir khac biet ve mire do ua thich giua cac mau 34

Hinh 17: Anh huong cua bao bi d§n gia tri b trong bot lekima sau 3 tuan bao quan 36

Hinh 18: Anh hudng cua bao bi den ham luong p-carotene trong bot lekima sau

3 tuan bao quan 36

Hinh 19: Anh hudng ciia bao bi den mire do ua thich trong bot lekima sau

3 tuan bao quan 37

Hinh 20: Quy trinh san xuat puree lekima 41

Hinh 21: Quy trinh san xuat bot le ki ma 42

Hinh 22: Puree lekima trudc khi thanh trung pel

Hinh 23: Dieu chinh pH cho puree pel

Hinh 24: Bot lekima sau khi nghien ray pel

Hinh 25: Bot lekima cho vao bao bi pel

Tom lircc

Lekima la mot nguon nguyen lieu mdi dugc danh gia cao ve mat dinh duong tuy nhien khong dugc nhieu nguoi biet den Hau het trai lekima dugc su dung bang each an true tiep khi chin, va su dung trong mot so mon an dan gian Khi den mua thu hoach, lugng tieu thu khong dang ke dan den co mot so lugng ldn trai lekima bi bo phi Tu thuc trang do can thiet nghien cuu de cho ra san pham mdi tu trai lekima chin ma khong lam thay doi nhieu ve mdi vi mau sac va thanh phan dinh duong

Noi dung nghien cuu cua de tai gdm:

- Khao sat cac yeu to anh hudng den chat lugng san pham puree lekima

+ Anh hudng ciia pH va che do xir ly nhiet den chat lugng san pham

+ Anh hudng ciia bao bi den su thay doi chat lugng san pham

- Khao sat cac yeu to anh hudng den chat lugng san pham bot lekima

+ Anh hudng ciia ti le maltodextrin va nhiet do say den chat lugng san pham

+ Anh hudng ciia loai bao goi den su thay doi chat lugng ciia bot lekima

Ket qua nghien cuu dat dugc nhu sau:

- Phdi tron maltodextrin voi ti le 30% de dat chat lugng cao nhat ve mau sac va miii vi

- Say d nhiet do 60°C de dam bao mau sac, miii vi san pham ft thay doi nhat, thoi gian say tuong doi ngan va dam bao tfnh kinh te cho qua trinh san xu&t

- Bao bi PA giu dugc mau sac tu nhien ciia bot lekima, ham lugng p-carotene cao mui

vi tu nhien va co muc do ua thfch cao nhat trong thoi gian 3 tuan bao quan

J

Chirong 1 Gioi thieu

de che bien thuc pham mdi Lekima la mot ngudn nguyen lieu mdi dugc danh gia cao

ve mat dinh duong tuy nhien khong dugc nhieu ngudi biet den

Hau het trai lekima dugc su dung bang each an true tiep khi chin, va su dung trong mot so mon an dan gian Khi den miia thu hoach, lugng tieu thu khong dang ke dan den mot so lugng ldn trai lekima bj bd phi Tir thuc trang do can thiet nghien cuu de cho ra san pham mdi tir trai lekima chin ma khong lam thay doi nhieu ve mui vi mau sac va thanh phan dinh duong

Puree dugc tao thanh bang each nghien nhao nguyen lieu va bao quan dich nhuyen do bang mot trong ba each: dong hop vo triing, xir ly bang nhiet sau do dong hop, lam lanh nhanh Bot lekima dugc xii ly bang nhiet say kho co the sir dung tao mau trong che bien thay cho phu gia tao mau gay hai cho sire khoe hoac sir dung true tiep cho cac mon soup, bd sung vao cac mon an ca hai san pham deu dam bao tir nhien khong sir dung phu gia, dam bao tot cho sire khoe Van de la phai nghien cuu che bien san pham mdi tir trai lekima sao cho tien lgi cho viec sir dung va dam bao chat dinh duong tot cho sire khoe mac du chi la budc nghien curu d phong thi nghiem

1.2 Muc tieu nghien cihi

Tren co so san xuat bot va puree tir trai lekima chin tao ra cac san pham tien lgi cho ngudi tieu dung Do vay muc tieu dat ra cho viec nghien curu la: tim ra cac thong so ky thuat toi uu cho quy trinh che bien san pham puree va san pham bot tir trai lekima

1.3 Noi dung nghien cuu

- Khao sat cac yeu to anh hudng den chat lugng san pham puree lekima

+ Anh hudng cua pH va che do xir ly nhiet den chat lugng san pham

+ Anh hudng ciia bao bi den sir thay doi chat lugng san pham

- Khao sat cac yeu to anh hudng den chat lugng san pham bot lekima

+ Anh hudng ciia ti le maltodextrin va nhiet do say den chat lugng san pham

+ Anh hudng ciia loai bao bi den sir thay doi chat lugng ciia bot lekima

Chirong 2 Lir<yc khao tai lieu

2.1 Tong quan ve nguyen ligu

2.1.1 Lekima

Ten: Lekima con ggi la lu cu ma, sapotille, sa-poteMamey

Ten khoa hoc: Lucuma mammosa Gaerth Vitellaria mammosa Radlk, Calocarpum mammosu, Pierre

Ho: Sapotaceae (hong xiem) (Do Tat Loi, 1977)

2.1.1.1 Motd

Cay Lekima da dugc mo ta bdi Kamnanayake (1992), Morton (1987; 1992), Troup (1986), Verdcouzt va Meijer (1995), Watt (1972), Wealth of India (1985)

Dac diem: Lekima la mot loai cay co kich thuoc trung binh, cay cao khoang 12-20m

va co duong kinh than cay 25-60cm V6 cay mau xam den gan min va day 4-5mm Co nhua trang trong t4t ca cac phan ciia cay Cac nhanh chii yeu nam ngang

La: La so le, nhung chii ySu tap hgp thanh mot nhom theo vdng xoan d tren dinh ciia cac canh, la hinh trung ngugc, kich thuoc 6-28><2,5-8cm, bong, mau xanh la cay, hudng ve phia dinh, nhieu va giam dan ve phia dudi Cuong la dai 5-25cm

Hoa: Hoa luong tinh, thorn, don doc, hoac moc thanh cac cum nhd, mgc d nach la, cuong hoa nhd dai 5-12cm Co 5 hoac 6 thiiy, mau kern, long mugt, dai khoang 8-11mm

Trai: Hinh trung ngugc qua mgng trdn, day com co hat voi dinh nhgn Khi chua chin,

vd trai co mau xanh la cay Khi chin da co mau vang chanh, vang vang, hay bi tim tai, mau cam vang, rat min va bong Huong vj nggt ngao, co miii thorn nhieu Hat dai 2-5,3cm, rong 1,3-3,2cm, g£n nhu hinh bau due hoac thudn dai, bong va co mau nau hat

de Ca hai dau hat giong deu co mau loi

Co su khac biet dang ke nhu thoi diem ra hoa va ket trai giua cac loai cay giong Voi khi hau nhiet doi ra hoa keo dai tir thang mot den thang sau, mot so cay ra hoa trong suot ca n5m Trai cay chin 5-6 thang sau khi ra hoa Trai thudng truong thanh tir thang chin den thang hai

Hinh 1: Trai lekima chin

2.1.1.2 Thanh phan hoa hoc

Phan thit qua chiem tai 70% thanh phan cua trai chin Thanh phan cua thit qua dugc dua ra trong bang (1) Lekima la loai qua giau nang lugng, niacin, carotene (tien vitamin A) va acid ascorbic

Bang 1: Thanh phan dinh duong cua trai lekima trong lOOg

Gia tri nang lugng (kJ)

'Ngudn: Morton, 1992"

2.1.1.3 Gia tri su dung

Dung de an khi chin nhung khong dugc danh gia cao vi no khong gidn va ngon nggt nhu trai cay khac Sau khi loai bd vd va hat, lekima co the dugc su dung nhu cac loai trai cay khac, hoac nhu mot loai rau vdi mudi va hat tieu, nude cot chanh hoac xdt mayonnaise sau do dung tuoi hoac nudng banh

Lekima co the dugc pha trgn vdi sua va nhuc dau khau de thuc hien mot loai nude giai khat dinh duong cao Mot cbc sua trung giau dinh duong, dugc thuc hien bang each ket hgp vdi bgt lekima chin, sua, duong, vani, nhuc dau khau, gia vi hdn hgp dugc xay trong may xay sinh to Banh Mock-bf ngd co the dugc thuc hien vdi 1/2 coc bgt lekima nghien, 2/3 chen duong nau, 1/2 mudng ca phe mudi, 1/4 mudng ca phe hat nhuc dau khau, 1 mudng ca phe nude cot chanh, 2 qua trung, 2 coc sua dac, hoac kem nhat Hdn hgp nay dugc do vao mot cai khudn va nudng 1 gid d 121°C

Lekima co the dugc su dung de san xuat cac san pham thuc pham khac, chang han nhu banh xep, banh nudng, mut, thach, xi-rd va mut Lekima co the dugc su dung vdi banh

mi bang each danh min bot trong may xay sinh to, them duong, va nau phan bot nhao, cho them nude chanh hoac khong tuy thfch, sau do quet len be mat banh mi va nudng

(Pouteria campechiana (Kunth) Baehni D.K.N._G Pushpakumara ICPAF-Country Liaison Scientist to Sri Lanka, Department of Crop Science Faculty of Agriculture, University of Peradeniya, Peradeniya, Sri Lanka)

2.1.2 Sac to carotenoid va p-carotenoid

2.1.2.1 Sac to carotenoid

Carotenoide la sac to phan bo rdng rai trong thien nhien co mau vang, cam do Ngudi

ta thay carotenoide trong luc lap, sac lap (d cu carot) Trong thuc vat mau carotenoide thudng bj che phu bdi chlorophyll O cac la non ngudi ta co the thay mau carotenoide khi chlorophyll chua day du

Cau tao

Carotenoid co hai nhom cau tao carotene hydrocarbon xanthophyll Xanthophyll la carotenoid gdm nhieu chat dan xuat chua nhom hydroxyl, epoxy, aldehyde va ceton Carotenoide la sac to ma ve mat hoa hoc gan vdi carotene Do la cac hydrocacbon gdm cac don vi isopen Nhieu carotenoide chua 8 don vi carotene hay chua 40 nguyen tu carbon Dua vao thanh phan nguyen tu trong phan tu, cac carotenoide co the dugc phan lam hai loai, bao gdm carotene va xanthophyll Thuat ngu "xanthophyll" dung de chi cac dan xuat oxi cua carotene Thuat ngu "carotene" dung de chi carotenoide chi chua carbon va hydrogen, trong do P-carotene va lycopene (Nguyen Nggc Phuong Anh, 2010)

Tinh chat

Carotenoid co do hoa tan rat cao trong cac dung moi khong phan cue (bao gdm ca dau

va mo), nhung lai khong tan trong nude Chung thudng dugc tach khdi cac nguyen lieu thuc vat bang dau mo (petroleum ether), ether hay benzene Ethanol va acetone cung la nhung dung moi thfch hgp (Hoang Kim Anh, 2005)

Mau sac cua carotenoid dugc tao ra nhd sir co mat cua he cac noi doi lien hgp trong phan tu Do co nhieu noi doi lien hgp nen chung de bi oxy hoa, nhay cam vdi tia UV, oxy va anh sang Khi nhung tac nhan nay bi loai bo, carotenoid trong thuc pham rat ben, ke ca d nhiet do cao Tuy nhien no cung bi dong oxy hoa bdi cac gdc tu do xuat hien trong qua trinh oxy hoa chat beo Hien tugng dong oxy hoa dac biet ro ret khi co mat them lipoxygenase Carotenoid de bi oxy hoa nen co tfnh chdng oxy hoa Carotenoid lam vo hoat oxy doc than sinh ra do tiep xuc vdi anh sang, khong khf va do chdng su oxy hoa te bao Lycopen dugc biet dac biet hieu qua trong cdng viec vd hoat oxy doc than

Sir mat mau carotenoid

Su mat mau carotenoid rat quan trgng trong thuc pham Sir oxy hoa pha vo carotenoid tang manh khi co su hien dien cua sunfite va ion kim loai Su oxy hoa lien quan d§n nhiet do, do am, khf oxy, kim loai Do do can bao quan cac thuc pham chua nhieu carotenoid trong dieu kien nhiet do thap, khong co khong khf Enzyme lipoxygenase

lam tang nhanh sir oxy hoa cua carotenoid tao ra cac proxyt Cac chat nay lam mk

mau carotenoid

Theo Tran Thi Luyen (2006), mdi truong trung tfnh va kiem nhiet do se pha huy

carotenoid Cac dau hieu cho thay khi bao quan thit d nhiet do <= 0°C mac dku v l n

xay ra cac phan ung sinh hoa cham ben trong va oxy hoa mot ph&n d ben ngoai, song

carotenoid chi bien doi khong dang ke Dieu kien co mat oxy anh hudng ldn den ham luong carotenoid Chfnh muc do chua bao hoa cao cua cac carotenoid lam cho chung

de oxy hoa va su mat mau hoac giam mau la do phan ung cua peroxide va nhom radical tu do vdi carotenoid Anh sang cung lam tang nhanh qua trinh oxy hoa carotenoid Hudng ngan can su mat mau carotenoid

- Pha hiiy hoat tfnh cua enzyme oxy hoa lipoxygenase bang each chan

- Ngan can su tiep xuc vdi oxygen

- Dung chat chdng oxy hoa

Hinh 2: Cong thirc cau tao p-carotene

Tinh chat

Theo Hoang Kim Anh (2005), p-carotenoid d dang tinh the hinh do sam, co nhiet do nong chay d 180^-182°C, tan nhieu trong CH3OH, C2H5OH, khong tan trong nude Dung dich p-carotenoid co mau vang, no hap thu oxygen trong khong khf de tao thanh chat khong co hoat tfnh sinh hgc Mot gam p-carotenoid ket tinh thuong mai co 1,67 trieu don vi vitamin A Quang pho ciia p-carotenoid trong ete dau hoa (petroleum ete):

Lm a x= 450^465nm

Su chuyen hoa va hap thu facarotene, vitamin A trong co the

Qua trinh chuyen hoa cac carotenoid thanh vitamin A trong co the chii yeu d thanh ruot non va la mot qua trinh phuc tap Mot phan tu p-carotenoid dudi tac dung ciia enzyme carotenase trong gan, ruot se chuyen hoa thanh hai phan tu vitamin A Sau khi vitamin A va carotenoid trong thuc an dugc hap thu vao co the, se nhu hoa cung vdi mat va cac san pham tieu hoa lipid trong ruot non, dugc niem mac ruot hap thu Ty le thu carotenoid d ruot non khong hoan toan, trung binh vao khoang 1/3 lugng an vao

Ty le chuyen hoa thanh vitamin A trong co the bang 1/2 lugng hap thu Chat beo la thanh phan quan trgng trong viec hap thu carotene va vitamin A, bdi vi no la moi truong hoa tan vitamin A, carotenoid Protein dong vai trd quan trgng trong viec chuyen hoa vitamin A trong moi truong nude, dudi tac dung ciia enzyme se chuyen hoa thanh cac dang ciia vitamin A (Tran Van Thu, 2002)

Theo Tran Thi Luyen (2006), vitamin A khong ben vdi oxy, trong moi truong yem khf

co the ben toi 200°C, ben vdi kiem, acid d nhiet do thap, ndng do thap Trong moi truong acid vitamin A ben hon trong moi truong kiem Vitamin A tan trong dau nhung khong tan trong nude

- Chuc nang:

Theo Nguyen Trung Thuan va ctv (2002), vitamin A co quan he chat che vdi thi giac binh thudng Vitamin A cung het sue quan trong doi vdi viec duy tri sir hoan thien cua cac to chuc bieu mo Vitamin can thiet cho su sinh truong binh thudng cua bo xuong

va giup fch cho su phat trien va sinh truong ciia te bao

- Cac yeu to anh hudng toi ham luong vitamin A:

Trong che bien thuc pham do tac dong ciia cac yeu to moi truong cung lam cho vitamin A bien doi va mat hoat sinh ly ciia no Sir bien doi co phu thuoc va cac yeu to nhu ndng do vitamin A, dang tu do hay ket hop, pH mdi truong va nhiet do

Mdi truong trung tfnh va kiem, nhiet do se pha hiiy de dang cac vitamin, trong do co vitamin A va carotenoid

Dieu kien co mat oxy anh hudng rat ldn den ham luong vitamin A va carotenoid Qua thi nghiem cho thay neu bao quan san pham trong bao bi khong tham nude hoac chan khong hay trong khf tro thi sir mat mat vitamin A rat nhd

Anh sang cung lam tang nhanh qua trinh oxy hoa vitamin A, bdi le anh sang lam tang nhanh qua trinh oxy hoa lipid ( Tran Thi Luyen, 2006)

2.1.3 Acid citric

Acid citric d trong rau qua vdi ham luong kha cao, dac biet la trong cac loai qua co mui Acid citric co vi chua diu nen thudng dugc dung de dieu vi cho san pham, no la loai acid dugc su dung rong rai trong nude udng giai khat vi no lam cho san pham co mui thorn ngon hon so vdi cac loai acid khac

Muc dfch ciia viec bd sung acid la lam giam vi ngot gat cua duong tao vi hai hoa, lam tang huong vi cho san pham dac biet doi vdi cac san pham co cac hgp chat mui chi noi bat trong moi truong acid Ben canh do, acid citric con co tac dung kfch thfch tieu hoa, han che su oxi hoa,

Acid citric co cong thuc phan tu la C6H807 H20 , tinh the co mau tr^ng, nhiet do ndng chay 153°C, de hoa tan trong moi truong nude

2.1.4 Vitamin C (acid ascorbic)

2.1.4.1.Gioi thieu ve vitamin C

Vitamin C (acid ascorbic) tham gia vao cac qua trinh oxy hoa-khu trong co the, co trong qua ho co mui, vai, nhan (20-60mg%), ca chua, dau co ve, chuoi Vitamin C co nhieu trong rau, cu, qua dac biet co nhieu trong so ri, cam, quyt, xoai, 6i

Cong thuc phan tu:

Khoi luong phan tu:

Nhiet do ndng chay:

Do hoa tan trong nuoc:

Thoi gian giam phan nua:

Hang so phan ly:

K M nang trien quang:

Quang pho hap thu:

Hien dien the chuan:

Don vi quoc te cua tinh

chat hoat dong cua vitamin

2.1.4.2 Tinh chat cua vitamin C

C6H806 176,12g 190-192°C 333g/l (20°C) 10-20 ngay

Pk1=4,2;Pk2=ll,26 24° (trong nuoc), 48° (trong methanol)

Lmax=245nm, pH=l,5

Aaiiax=265nm, pH=6,8 0,166V dpH=4,0 va35°C HU=0,05mg acid ascorbic trong 0,1ml nuoc ep ho citron

Ten khoa hoc cua vitamin C la: y_lacton cua 2,3_dehyro L_gulonic acid hay ascorbic acid

Vitamin C trong tu nhien ton tai dudi ba dang pho bien la: acid ascorbic, acid dehydroascorbic va dang lien ket ascorbigen tat ca deu d dang L (Le Ngoc Tu, 2004)

Acid ascorbic se chuyen hoa cholesterol trong co the thanh mudi sunfat tan dugc trong nude va lam gia tang su bai xuat, dong thoi cung tham gia vao phan ung hydroxyl ciia cholesterol de hinh thanh nen acid cholic, lam giam ham lugng cholesterol trong mau (Nguyen Trung Thuan va ctv, 2002)

2.1.4.4.Su hap thu va bien duong ciia vitamin C

Khi vao co the vitamin C dugc hap thu d doan dau ciia ruot non bang su tham thau binh thudng va cudi cung di vao mau Trong co the ngudi, vitamin C ton tru nhieu nhat d nang thugng than, sau do la la lach Truong hgp thieu vitamin C lien tuc 19 ngay la nguyen nhan gay nen benh hoai huyet, neu thieu tiep tuc trong 16-17 tuan se dan den tu vong

Tuy nhien, do vitamin C co doi song qua ngan khong co kha nang ton tru nhieu trong

co the nen benh thieu vitamin C xuat hien rat nhanh va de dan den tu vong

Vitamin C sau khi dugc dua vao co the se dugc giu lai mot phan, phan lbn bi dao thai

ra ngoai qua duong tieu, theo phan hay bi oxy hoa thanh acid cacbonic (Vu Nggc Ruan, 2005)

2.1.4.5.Bien phap bao ve vitamin C trong che bien va bao quan

Khi bao quan hoa qua, neu phun C 02 qua nhieu lam cho ham lugng vitamin C giam xuong nhanh chdng

Vitamin C dugc 6n dinh khi co mat cac chat nhu saccharose, acid huu co, sorbitol, glycerin

Cac chat nhu carotene, flavin, penicillin cung tham gia bao ve vitamin C Cac chat nay gan voi cac chat oxy hoa vitamin C, vi vay vitamin C dugc bao ve

2.2 Maltodextrin

Theo dinh nghia cua Co quan thuc pham va Thuoc cua Hoa Ky (FDA) thi maltodextrin la mot polysaccharide khong ngpt, co cong thuc cau tao la (C6H1 0O5)n.H2O, la san pham thuy phan tinh bot khong hoan toan bang phuong phap hoa hgc (acid) hoac sinh hgc (enzyme) hoac ket hgp ca hai phuong phap (acid va enzyme) Maltodextrin co don vi la D-glucose, co duong lugng Dextrose Equivalent (DE) tu 4-f20

DE la dai lugng chi kha nang khu doi voi chuan la 100% d duong glucose (dextrose), hay so gam tuong duong D-glucose trong lOOg chat kho cua san pham Dac tinh cua maltodextrin phu thuoc vao chi so DE nhan dugc, co the d dang bot mau trang hay dang dung djch dam dac Maltodextrin la phu gia co nhieu ung dung trong cong nghe thuc pham va dugc pham, an toan cho ngudi dung true tiep

Maltodextrin co DE tu 4-3-7 dugc su dung de tao mang mdng de tan va tu huy dugc dung de bgc keo, bgc trai cay khi bao quan, dua vao kem, lam phu gia nude xdt, lam chat don tao vien trong cong nghiep san xuat do udng, dac biet la nude giai khat danh cho tre, keo gum mem, chat trg say, chat giu huong, chat co dinh mui, giup de hoa tan, yeu to tao hinh

Maltodextrin co DE tir 15-3-18 dugc dimg lam chat ket dinh, chat tang vi cho do udng,

ca phe hoa tan, lam vat mang cac thanh phan khong phai duong (Truong Thi Minh Hanh, 2008)

Bang 2: Mot so tinh chat cua maltodextrin

Maltodextrin Tinh chat

DE 4-E7 It hut am, pH 4,5-3-5,0, it nggt, hoa tan vdi 15% chat kho, dung dich co

do nhdt cao Ham lugng glucose 0,3%, maltose 2,9% chat kho

DE 9^-12 ft hut am, ft nggt, tham gia phan ung hoa nau, hoa tan toi 30% chat

kho Ham lugng glucose 0,8%, maltose 0,9% chat kho

DE 15-3-18 It hut am, ft tham gia vao phan ung hoa nau, hoa tan toi 603-70% chat

kho, nggt nhe Ham lugng glucose 1,3-3-1,6%, maltose 4,8^-5,8% chat kho

"Nguon: Hoang Kim Anh va ctv, 2005"

Bang 3: Tieu chuan chat lirong cua maltodextrin dang bot

Thanh phan Theo tieu chuan cua Grain Processing (s6 g trong lOOg san pham, Corporation, My

Glucid 94,5

Am 5,0 Tong protein, lipid, xa, tro <4,0

Tfnh chat vat ly: San pham dang bot hoac dang hat min mau trang Do hoa tan (*) cua

Maltodextrin Ml00 DE10 cua Grain Processing Corporation la 78 giay

Cac chi tieu vi sinh Mat s6 (CFU/lg mlu)

Tong vi khuan hieu khf 100

Nam moc 50 Nam men 50

E.coli Khong co

Salmonella Khong co

(*) Do hoa tan dugc tinh hang thai gian hoa tan hoan toan san pham dang bot trong

nuoc voi ndng do 5% (w/w) d nhiet do thudng

"Nguon: Hoang Kim Anh va ctv, 2005"

2.3 Cac qua trinh, nguyen ly che bien va bao quan co lien quan

2.3.1 Qua trinh rira

Theo Le Van Tan (2008), nguyen lieu qua dugc rua sach bang nude sach trudc khi dua

vao che bien, trudc do qua dugc xu ly bang thuoc sat trung hoac mot so hoa chat khac

Nude dugc clo hoa bang each bd sung mot lugng nhd chat tay Sau do, qua dugc trang

qua bang nude sach Qua trinh rua khong chi loai bd cac loai dat trong va vi sinh vat

be mat ma con tach bd thudtc diet nam, thuoc diet con trung, va thuoc tru sau Nude

rua rau qua can su dung mot lugng nude ldn De rua lugng rau qua ldn can dung toi

may rua co hgc Nhung may co cau tao kieu thung quay, ben trong co ban chai, tuy

nhien chi su dung cho qua cung kho dap

2.3.2 Qua trinh hoc vo

Theo Le Van Tan (2008), trong nhieu san pham rau qua, boc vd da loai bd dugc phan

ldn vi sinh vat tren be mat rau qua song Cac vi sinh vat con sot lai sau khi rua tiep tuc

dugc loai bd trong thoi gian boc vd Boc vd bang kiem con tieu diet dugc hau het cac

vi sinh vat Boc vd dugc tien hanh theo nhieu each khac nhau: co hgc (lam tray xudc

vd, su dung dao, may ggt thung quay), hoa hgc (dung dich kiem ndng), nhiet (nhiet

am, nhiet kho)

2.3.3 Qua trinh thanh triing

Thanh trung la qua trinh xu ly nhiet tuong doi on hoa nham bao quan thuc pham bang

each vo hoat enzyme va diet mot so vi sinh vat tuong doi nhay cam vdi nhiet do La

phuong phap cat giu thuc pham theo nguyen If tieu diet mam mong gay hu hong thuc

(2) (3) (4) (5)

phlm Thanh trung bang nhiet do cao cua hoi nude va nude ndng la phuong phap thanh trung phd biln nhat trong san xuat do hop (Nguyen Van Tiep va ctv, 2000)

Khi nhiet do gia tang din qua nhiet do toi thfch cua vi sinh vat thi hoat dong cua vi sinh vat cham lai va khi nguyen sinh chat cua vi sinh vat dong tu dudi tac dung nhiet thi chung se chit B l bilt dugc muc do tieu diet vi sinh vat ciia qua trinh thi can phai bilt tri sd D va z bilu thi cho loai vi sinh vat do Su tieu diet vi sinh vat dugc the hien theo phuong trinh sau:

dN/dt = -kN (1)

Trong do:

- N : lugng vi sinh vat trong san pham theo thoi gian t

- k: hang sd tdc do, k nay thay doi tuy theo loai vi sinh vat va tfnh chat cua do hop

- (dN/dt): van tdc tieu diet vi sinh vat

Co the viet phuong trinh 1 dudi dang:

(dN/dt)/N = -k

Hay: t = (l/k)*ln(No/N)

Hoac: t = (2,303/k)* log(No/N)

Suy ra: Log(N(/N) = -(k/2,303)*t

Vdi D la thoi gian can thiet tai mot nhiet do xac dinh de tieu diet 90% lugng vi sinh vat ban dau, ggi la thoi gian tieu diet thap phan (phut)

Van tdc k va thoi gian D co moi lien he nhu sau:

( - l/D) = -(k/2,303)

Vi vay (4) co thi vilt thanh: t = D*(Nq/N) (6)

Vdi F: thoi gian (phut) de tieu diet vi sinh vat tai mot nhiet do xac dinh

z: khoang nhiet do can thiet de tang (hoac giam) D 10 lan

Fz T r e f = t*10( ( T-T r e f ) / z )

Vdi Tref: nhiet do tuong ung vdi qua trinh xu ly nhiet

z: tuy thuoc vao loai vi sinh vat can tieu diet va tfnh chat ciia san pham, ngudi ta lay z

= 10°C dai dien cho loai chiu nhiet sinh bao tu Clostridium Botulinum, (Nguyen Van

Tilp va ctv, 2000)

Truong hgp nhiet do thay doi theo thoi gian, khi do F tfnh nhu sau:

FZ Tref = f 101 ( T ( 0 "T r e 0 / Z ]* d t = I 1 0[ ( T ( t ) "T r e f ) / Z ]* At

No co y nghia la tfnh tren tong thoi gian anh hudng tuc thoi, ma da dugc bieu thi 10((T"

T r e f ) / Z ) ggi la ylu td Bigelow (Le Bach Tuylt, 1996)

Che do vd cong thuc thanh trung

Theo Nguyen Van Tiep va ctv (2000) moi dang do hop thanh trung trong cac thiet bi khac nhau deu co mot che do thanh trung khac nhau, che do thanh trung ciia do hop bieu thi theo cong thuc:

a-A- B - C * p

t Vdi

a: thoi gian xa khi trong thiet bi thanh trung km

A: thoi gian nang nhiet (phut)

B: thoi gian giu nhiet (phut)

t: nhiet do thanh trung ( C)

p: ap suat doi khang

Nhiet do thanh thing: can cu vao chi sd pH cua do hop ma chia thanh 3 nhom san pham nhu sau:

- Nhom khong chua: co pH ldn hon 6,0

- Nhom ft chua: co pH tu 4,5-3-6,0

- Nhom chua: pH nhd hon 4,5

Khi chon nhiet dp thanh trung can cu vao chi so acid san pham:

- Neu pH ldn hon 4,5 thanh trung d 105 -421°C

- N l u pH nhd hon 4,5 thanh trung d 80 -3-100°C

Thai gian thanh trung

Khi thanh trung do hop, khong phai tat ca moi diem trong do hop deu dat nhiet do thanh trung cung mot luc, ngay ca khi dat nhiet do thanh trung thi vi sinh vat khong bi tieu diet ngay nen thoi gian thanh trung ciia do hop bao gdm thoi gian truyen nhiet d moi truong dun ndng vao trung tarn hop va thoi gian tieu diet vi sinh vat Trong thoi gian thanh trung, san pham dung trong hop khong dupe dun ndng tuc thoi toi nhiet do thanh trung can dat dupe ma phai chuyen doi tu moi truong dun ndng, qua bao bi vao lop san pham ben ngoai, rdi mdi vao tarn do hop Qua trinh phai mat mot thoi gian goi

la thoi gian truyen nhiet Khi tarn do hop dat toi nhiet dp thanh trung thi giu nhiet d nhiet do trong thoi gian nhat djnh gpi la thoi gian tieu diet Vay thoi gian thanh trung gdm: thoi gian nang nhiet, thoi gian giu nhiet, thoi gian ha nhiet

2.3.4 Qua trinh say

Say kho la phuong phap bao quan rau qua, thuc pham cd tu lau doi va dupe su dung

rdng rai trong nhan dan Trong doi song hang ngay ngudi ta thudng phoi sky kho cac san pham ndng nghiep de cat giu Phuong phap nay la phuong phap sky tu nhien Mng

anh mat trdi, thudng lau va ton that nhieu sinh to do tac dung cua anh sang Trong cong nghiep ngudi ta thudng dung cac thiet bi say

San pham ndi chung va rau qua ndi rieng la mdi truong thuan loi cho vi sinh vat phat trien va cho cac hien tuong trao doi chat xay ra Da sd cac vi khuln chi co t h i phat

then d dieu kien do am mdi truong 30%, mot sd nam mdc phat then d do am 15% Khi san pham d trang thai khd tuyett ddi moi qua trinh trao doi chat ngirng lai Nhung trong thuc te khong bao gid say den do khd tuyet ddi ma chi say den gidi han nao do dam bao khong cho vi sinh vat hoat dong Vf du rau thudng say den do am gidi han 14%, con qua d 18-24% Vdi cac loai qua say khd ham luong nude con cao hon va luong duong hoa tan trong qua cd tac dung uc che hoat dong cua vi sinh vat

Co rat nhieu phuong phap say rau qua nhu: Say tu nhien bang anh mat trdi, say bang khong khi ndng, ddi luu, say thang hoa Du bang phuong phap nao cung can edehat luong dung va tieu chuln tot (Nguyen Thi Minh Phuong, 2008)

Cac giai doan say

Trong qua trinh say, do am cua vat lieu say lien tuc thay ddi theo hudng giam dan Tuy cau tao cua vat say va phuong phap say ma do am va nhiet do cua vat say d cac phan ben trong va tren be mat cung khac nhau theo tirng giai doan say Cac giai doan say bao gdm: giai doan dau hay con goi la giai doan dun ndng vat say den nhiet do bay hoi ciia am, giai doan thu nhat hay giai doan co tdc do say khong ddi, giai doan thu hai con goi la giai doan tdc do say giam dan

De giai thfch cac giai doan say ta su dung qua trinh say ddi luu 0 day ta dung tac nhan say la khong khf cd do am tuong ddi (cpt), nhiet do tt, tdc do wt, la on dinh (khong thay ddi) Vat say mdng, qua trinh say cham sao cho do am va nhiet do d moi chd la nhu nhau

O giai dau (dun ndng), nhiet do tac nhan say cao hon nhiet do bay hoi cua am, nhiet do cua vat say dupe nang len den nhiet dp bay hoi cua am

Thoi gian cua giai doan dau dupe tfnh tir cong thuc sau:

xo \ 0 a(t- t m) di = p 0 R v ' b \,cdt = p 0 R vlb \ 0 (c 0 + C n u)dt

Qua trinh say chi co the xay ra khi nhiet dp ciia vat say cao hon nhiet dp diem suong ciia tac nhan say, neu ngupc lai, hoi nude tir tac nhan say se ngung va tham vao vat say

Trong giai doan say thu nhat, nhiet dp ciia vat say bang nhiet dp bay hoi nude Tdc dp bay hoi nude va nhiet dp ciia vat say la khong thay ddi Nhiet luong tir tac nhan say truyen cho vat say cap het cho nude bay hoi:

q = a(t t -tj

Trong giai doan say thu nhat, chii yeu la lam bay hoi nude tu do trong vat say Hoi bay len tir be mat vat say la hoi nude bao hoa, nhiet hoa hoi dung bang nhiet hoa hoi ciia nude tu do

Ta co: du/dx =( a/(p 0 R v r n ).( (t t - t b ) (*)

a: he sd tda nhiet tir tac nhan say cho vat lieu say

t t : nhiet dp tac nhan say

r^/nhiet dp bay hoi ciia nude

r n : nhiet hoa hoi cua nude

u: dp am trung binh ciia vat say

r: thoi gian say

Doi voi vat say khong co kich thuoc, d giai doan thu nhat ciia qua trinh say cac thong

sd ve phai ciia phuong trinh * la cac hang sd Neu vat say co kich thuoc chut ft thi a

va Rv se thay ddi tang len nhung ty sd ciia chiing khong ddi Nhu vay cd nghia la du/dt

= const V i vay giai doan thu nhat con goi la giai doan tdc do say khong ddi

De cd tdc do say khong ddi, luong am da bay hoi phai bang luong am sau ben trong truyen ra be mat ciia vat say Neu dan am khong kip bay hoi thi vung bay hoi am se lan sau vao phfa tarn ciia vat say Khi do d vat say hinh thanh ba vung co nhiet do khac nhau Vung tarn ciia vat say goi la vung am, vung tiep theo la vung bay hoi am, vung thu ba la vung say hoan thanh Nhiet do tuong ung ciia tirng vung thda man dieu kien sau: ti<t2<t3

Nhiet do ciia vung khd chfnh la nhiet do be mat ciia vat say (t3 = tm) Nhiet do vung hai bang nhiet do bay hoi (t2 = tj,) Nhiet do ciia vung ba se tang dan va bang tac nhan say Vung 2 cang lan sau vao trong thi vung 1 co lai, vung 3 md rong Trong qua trinh nay thi nhiet do trung binh ciia vat say tang dan V i vay giai doan nay goi la giai doan thii hai hay giai doan tang nhiet do ciia qua trinh say

Trong giai doan nay (tt - t3) giam dan do t3 tang dan den bang tt d vung 3 bat dau bay hoi nude lien ket nen r> rn

Nhung dieu kien deu dan den ket qua lam giam du/dx, nen con goi la giai doan giam tdc do say

Tdc do say khong ddi d giai doan thii nhat, giam dan d giai doan thu hai, bang khong khi qua trinh say dat do am can bang vdi tac nhan say

Theo Nguyen Van May (2004), lira chon phuong phap va che do say:

- Say bang khong khi

Moi truong khf rat thudng dupe dung de gia nhiet trong viec say Khong khf thoi qua thuc pham tren mam, bang chuyen, lay hoi am va mang ra khdi thiet bi say do

Hoi am dupe chuyen khdi be mat san pham do khong khf, tien trinh boc hoi dupe tiep tuc bdi sir chuyen am tir ldp ben trong ra ngoai Tien trinh nay dupe tiep tuc cho den khi cac hat tir khd den dp am mong mudn Ldp vat lieu bd tri sao cho khong qua day, tao mot su tiep xuc phoi bay trong khong khf de mong mudn co dupe sir boc hoi am thuan loi

Tdc dp hoi am gia tang den giai doan dang tdc tuong ung vdi nhiet bau udt Tdc dp say on dinh den khi nude tu do tach hau het khdi san pham, ke do tdc dp giam dan den khong

Cac thuc pham nhay cam vdi oxygen nhu sua hay mot sd nude trai cay phai dupe dat trong bao km khf, chua nito tro ngay say khi sly Sly trong dong khf C 02 hay them chat chdng oxy hoa vao san pham doi khi dupe de nghi

- Say chart khong

Trong may say chan khong, vat lieu thudng tiep xuc vdi mam hay true gia nhiet nhung toan bd don vi dugc dat trong budngng chan khong va hoi nude dugc nit vao mot may ngung tu Nhiet do sdi ciia phan long vat lieu dugc giam thap dudi dieu kien chan khong, nude sdi gan 50°C d ap suat 13,3kPa va cac chat nhay cam nhiet trong vat lieu

am dugc bao ve tdt

Cac bien ddi sinh ly, sinh hoa

Bien ddi vat ly

Co hien tuong co the tfch, khdi luong rieng tang len, giam khdi luong do luong nude bay hoi

Bien ddi hoa ly

- Khuech tan am: Trong giai dau ciia qua trinh say, am khuech tan tir ldp ngoai vao trong vat lieu do dan no vi nhiet Day la su ddi am gay nen do sir chenh lech nhiet do cac phan khac nhau cua vat lieu sau

- Ngoai su khuech tan am: Trong qua trinh say con hien tuong chuyen pha tir long sang hoi cua am va cd anh hudng ciia he keo trong qua trinh say, tuy tfnh chat vat lieu

co chua keo hao nude hoac keo ghet nude Neu keo ghet nude lien ket long leo, de khuech tan

Bien ddi hoa hoc

Xay ra hai khuynh hudng

- Tdc do phan ung hoa hoc tang len do nhiet do vat lieu tang nhu phan ung oxy hoa khir, phan ung Mailard la phan ung tao mau khong enzyme ciia protein va duong khu: phan ung phan huy protein giam kha nang thfch nghi vdi su tach nude

- Tdc do phan ung hoa hoc cham di do mdi truong nude bi giam dan, vf du mot sd phan ung thiiy phan Thong thudng trong hai xu the tren, xu the mot troi hon

- Ham am giam dan trong qua trinh say Thudng am phan bd khong deu trong vat lieu nhat la cac vat lieu cd kich thuoc ldn

Bien ddi sinh hoa

- Giai doan dau cua qua trinh say, nhiet do vat lieu tang dan va cham tao ra sir hoat dong manh me ciia cac he enzyme oxy hoa khu, gay anh hudng xau den vat lieu, vi vay thudng diet peroxidase va polyphenoloxydase trudc khi say

- Giai doan say, hoat dong enzyme giam vi nhiet do hoat dong va luong nude giam chi con tiep tuc hoat dong yeu trong thoi gian bao quan va toi mot giai doan co kha nang hoat dong

Trong thuc te cho thay cac enzyme khong mat hoat tfnh do xu ly so bo hoac do tac dong ciia nhiet do trong qua trinh say co the dan den hieu qua tao mau cua polyphenol hoac thuy phan lipid

Bien ddi sinh hoc

Cau tao te bao: thudng xay ra hien tuong te bao song thanh te bao chit do nhiet do lam bien tfnh khong thuan nghich chat nguyen sinh va mat nude

V i sinh vat: co tac dung lam yeu hay tieu diet cac vi sinh vat tren be mat vat lieu Cac

vi sinh vat d san pham say thudng khd phat trien nhung sd luong vi sinh vat tren mot don vi san pham thudng ldn hon cac san pham long khac Chii y, bao tu vi sinh vat hau nhu khong bi tieu diet trong qua trinh say

Ve sinh: trong qua trinh say cong nghiep san pham say thudng lan tap chat gia cong nhu cat, san

Dinh duong: san pham khd thudng giam do tieu hoa, luong calo tang do giam do am, nen cd the giu luong it nhung du calo, do la tinh uu viet cua cac san pham thuc pham khd dugc su dung trong cac linh vuc qudc phong va cac linh vuc khac

Bien ddi cam quan

Mau sac: mat sac to hay giam sac to do tac dung ciia nhiet do (gia tri tuyet ddi) nhung tang gia tri tuong ddi len do nude mat di, vi vay cuong do mau tang len Ndi chung co mau tham, mau nau do phan ung caramen hoa, phan ung tao melanoidin va oxy hoa cac polyphenol

Chi tieu mau sac ciia san pham say la mot trong cac chi tieu quan trgng Khi da chon dugc che do say thfch hgp qua trinh say cd tac dung cd dinh mau sac ciia san pham va tao ra hinh dang dep ciia san pham

Mui: mot sd chat thorn bay hoi theo am va do nhiet do bi phan huy gay ton that chat thorn, dac biet la cac chat thorn ciia cac san pham thuc pham co ngudn gdc sinh hgc Vi: do do am giam nen ndng do chat vj tang len, cuong do vi tang

Trang thai: gan lien ket vdi cac bien ddi vat ly va hoa ly nhu tang tfnh dan hoi, tfnh dai, tfnh truong no (Le Bach Tuyet, 1996)

2.4 Cac nghien cihi trirdc day (trong va ngoai nirdc)

Theo Huynh Thi Cam Tii (2007) "Nghien cuu che bien bot budi hoa tan" tac gia ket luan rang:

+ Khi say d nhiet do 80°C va dat ndng do chat khd 42°Brix san pham cho gia tri cam quan cao nhat ve mau sac, mui va vi

+ Ndng do chat khd cang cao thi do am san pham cang thap, bao quan cang lau, tuy nhien mui san pham khong tdt do lugng maltodextrin bd sung nhieu

Theo Nguyen Thi Hao (2012) "Nghien cuu che bien bot hat sen-me den" tac gia ket luan rang:

+ Hat sen dugc say d 70°C trong thoi gian 330 phut den do am 4-3-5%

+ Bot me den, maltodextrin, sua bot dugc phdi trgn cung vdi hat sen vdi ti le tuong ung la 15%, 30% va 60% khdi lugng bot hat sen sau khi say va xay nhuyen San pham sau khi phdi trgn co gia tri cam quan nhu mau sac, mui, vi va trang thai tdt nhat, an toan ve ve sinh

Theo Trinh Thanh Tarn (2008) "Nghien cuu che bien bot dinh duong tu mot sd loai rau qua thong dung" tir cac nguyen lieu khoai lang, dau nanh, ca rot vdi cac thong sd toi uu trong quy trinh che bien nhu sau:

+ Khoai lang dugc say d 65°C trong thoi gian 9 gid 20 phut, dau nanh dugc say d 65°C vdi thoi gian say khoang 9 gid, ca rot dugc say d 70°C, trong thoi gian 6 gid Tat ca cac nguyen lieu deu dugc say den do am dung 43-5%

+ Ti le phdi trgn toi uu giua cac nguyen lieu la 60,80% bot khoai lang, 26,92% bot dau nanh, 6,32 bot ca rot va 5,29% sua bot

Theo Ngd Van Thinh (2009) " Nghien cuu che bien bot dinh duong cho ngudi cao tudi" tir cac nguyen lieu bi do, dau den, gao luc vdi cac thong sd toi uu trong quy trinh che bien nhu sau:

+ B i do dugc say d 60°C trong thoi gian 10 gid 35 phut, dau den dugc say d 70°C vdi thoi gian say khoang 7 gid 15 phut, gao luc dugc say d 70°C, trong thoi gian 7 gid 50 phut Tat ca cac nguyen lieu deu dugc say den do am dung 4-3-5%

+ Ti le phdi trgn toi uu giua cac nguyen lieu la 50,68% bot gao luc, 2,51% bot dau den, 7,13% bot bi do va 39,68% sua bot

Theo Ho Thanh Phong (2011) "Nghien cuu che bien bot mit tir hat mit" tac gia da ket luan rang:

+ Su dung NaHS03 vdi ndng do 0,3% va ngam trong thoi gian 10 phut thi san pham

cd mau sac tdt va khong cd miii hang khd chiu

+ Say san pham d 70°C trong thoi gian 60 phut thi san pham cd do am bao quan an toan va dat cam quan tdt

Theo Nguyen Thai Loc (1997) "Nghien cuu san xuat va ton tru puree chuoi": Chuoi dugc boc vd, cat thanh doan 4cm, sau do ngam trong nude de ngan chan tiep xuc vdi oxy khong khi Dem chuoi chan trong nude sdi 100°C trong 12 phut Sau do chuoi dugc dem di xay, cha va them ti le nudc/thit qua = 1

Chirong 3 Phirong tien va phirong phap nghien ciru

3.1 Phirong tien nghien ciru

3.1.1 Dja diem va thoi gian nghien ciru

Cac thi nghiem dugc thuc hien tai phong thi nghiem Bo mon Cong Nghe Thuc Pham, Khoa Ndng Nghiep Tai Nguyen Thien Nhien, Truong Dai hgc An Giang

3.1.2 Nguyen vat lieu, thiet bj can cho thi nghiem

Nguyen lieu

- Trai lekima chin

- Maltodextrin

Hoa chat va phu gia

- Dung djch NaOH 30%, NaOH 10 %

- Dung djch Pb(CH3COO)2 30 %

- Dung djch Na2S04 bao hoa

- Metyl xanh 1 % trong nude

- Fehling A: CuS04tinh t h i 69,28g djnh muc 1 lit

- Fehling B: Kali Natri tatrate 364g NaOH lOOg dinh muc vira du 1 lit

- Phenolphtalein 1 % trong con

- Cac hoa chat khac

- Cac dung cu can thiet khac

3.2 Phirong phap nghien ciru

Dua tren quy trinh san xuat de ra thu nghiem de tim ra thong sd tdi uu nhlt

Phuong phap lay mau

TRUONG DAI HOC

AN GIANG

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Nguyen lieu dugc chgn a do chin phu hgp cho che bien de dam bao chat lugng san pham tot, cung mot ngudn nguyen lieu de dat ket qua cao

Phuong phap nghien cuu

Thong so cac thi nghiem khac dugc giu lai cac thi nghiem sau

LSD va thong ke theo stagraphic

Phuong phap phan tfch

Xac djnh ham lugng duong trong nguyen lieu dua vao phan ung giua duong khu vdi ion Cu2 + trong dung dich Fehling thanh Cu20 co mau do gach

Do ham lugng chat kho hoa tan su dung Brix ke

Do pH bang pH ke

Do do mau bang may so mau do gia tri L a b

Danh gia cam quan san pham

Bang 4: Bang cac phirong phap danh gia cam quan

Cac chi tieu ve mau sac, miii vi, cau true se dugc cho diem theo thang diem mo ta Diem tir 0 den 5, mau cd chat lugng cang tdt khi diem cang cao

Mau sac cac mau dugc xep theo thu tu tang dan theo cuong do mau dac trung cua san pham Sau do dua vao sd thu tu quy ddi thanh diem rdi tien hanh thong ke xu ly sd lieu

Bang 5: Thang diem Hedonic

Diem Yeu cau

9 Thich cue do

8 Rlt thich

7 Thich vira phai

6 Thich hoi hoi

5 Khong thich khong chan

4 Chan hoi hoi

3 Chan vira phai

2 Chan rat nhieu

1 Chan cue do

3.3 Qui trinh nghien ciim du kien

3.3.1 Qui trinh san xuat puree le ki ma

Hinh 3: Quy trinh san xuat puree lekima

3.3.2 Quy trinh san xuat bot le ki ma

Lekima

1

Xir ly so bo

Nghien

Maltodextrin 1 • Phoi tron

3.4 Thuyet minh quy trinh

3.4.1 Qui trinh san xuat puree le ki ma

- Lira chon nguyen lieu: Lekima dugc mua tir chg, lira chgn le ki ma chin vang, mem, nut vo, co mui thorn Khong dung lekima chua chin vi co nhieu nhua va vi chat Co the mua lekima gia va de chin dung dan

- Xir ly le ki ma: Lekima dugc rira sach, sau do tach lay phan thit lekima, loai bo vo, hat nhtrng phan thit bi chay cung, sau hoac bi dap cho cong doan tiep theo

- Xay: Dung may xay sinh to lam min phan thit lekima, xay vdi sd lugng it va them ti

le nude thich hgp (1000ml nude/lkg thit lekima) de may xay co the hoat dong de dang

- Cha: Tao do min dong nhat, cha giup loai bd nhung phan thit qua bi von cue hay nhung thanh phan lam anh hudng den mau sac cua san pham

- Bao goi: San pham dugc cho vao bao bi va bao quan lanh

3.4.2 Quy trinh san xuat bot le ki ma

Lekima chin dugc xu ly so bg, loai bd vd va hat

- Nghien: Dung mudng nghien phan thit qua nham pha vo cau true le ki ma, lam nhd vat lieu giup phdi trgn de dang, tao thuan lgi cho qua trinh say, ray

- Phdi trgn: Phdi trgn hdn hgp vdi maltodextrin Maltodextrin cd tac dung ket dinh tao cau true dong deu cho hdn hgp sau phdi trgn

- Say: Lam khd san pham vdi nhieu nhiet do nham tao cau true, cam quan va bao quan tdt nhat Say den do am dirng 8%

- Nghien ray: Loai bd von cue, cac tap chat, tao cho san pham co do min dong deu

- Bao goi: San pham dugc cho vao bao bi va bao quan

3.5 Noi dung nghien ciru

3.5.1 Thi nghiem 1 : Khao sat cac yeu to anh hudng den chat luong san pham puree lekima

3.5.1.1 Khao sat hudng cua pH va che do xu ly nhiet do den chat luong san pham Muc dich:

Tim ra nhiet do thanh trung va gia tri pH thfch hgp nham dam bao chat lugng san pham tdt nhat

Hinh 5: So do bo tri thi nghiem 1

P: gia trj pH cua puree lekima

N: nhiet do xu ly, (°C)

N1 = 95 N2= 1 0 0 N3= 1 1 0 N4= 1 1 5

So mau thi nghiem: 4*4*3 = 48 mau

Thi nghiem dugc thuc hien voi 3 lan lap lai

Chi tieu theo ddi

Mau sac dugc theo doi bang thiet bi do mau

Ham lugng p-caroten sau khi gia nhiet

Puree lekima (da thuc hien theo ket qua tot nhat cua thi nghiem 1)

Tien hanh:

Cho vao ba loai bao bi vdi 200ml puree lekima sau do tien hanh theo doi theo thoi gian Thoi gian theo doi va phan tich theo dinh ki 1 tuan, 2 tuan, 3 tuan, d nhiet do lanh 10°C

Hinh 6: So do bo tri thi nghiem 2

B 2 = bao bi thuy tinh

B: loai bao bi

Bi = bao bi hop nhua

Sd mau thi nghiem: 3*3 = 9 mau

Cac thi nghiem dugc thuc hien lap lai 3 lan

Chi tieu theo ddi

Mau sac: su bien ddi mau sac theo thoi gian

Muc do ua thich

B 3 = bao bi PA

Ham lugng (3-caroten

3.5.2 Thi nghiem 2: Khao sat cac yeu to anh huong den chat luong san pham bot lekima

3.5.2.1 Khao sat anh huong cua ti le maltodextrin va nhiet do say den chat luong san pham

So mau thi nghiem: 3*4*3= 36 mau

Cac thi nghiem dugc thuc hien lap lai 3 lan

Chi tieu theo ddi

Mau sac, muc do ua thich

Ham lugng p-caroten

S 2 = 6 0( ,C ± 2 ° C

S 4 = 8 0 ° C ± 20C

3.5.2.1 Khao sat anh hudng ciia loai hao hi den chat lugng san pham

B: loai bao bi

Bp bao bi hop nhua

So mau thi nghiem: 3*3 = 9 mau

Cac thi nghiem dugc thuc hien lap lai 3 l l n

Chi tieu theo ddi

Mau sac

Muc do ua thich

Ham lugng (3-caroten

Hinh 8: So do bo tri thi nghiem 4

B 2 : bao bi thuy tinh B 3 : bao bi PA

Chirong 4 Ket qua va thao luan

4.1 Thanh phan hoa hgc cua trai lekima

Be xac dinh thanh phan hoa hoc ciia lekima co anh hudng nhu the nao den qua trinh

chi biln va thanh phan hoa hoc nay thay ddi nhu the nao trong qua trinh che bien, tien

hanh phan tich mgt sd thanh phan co ban ciia nguy en lieu

Bang 6 : Thanh phan hoa hgc cua lekima tinh tren % thit qua

Thanh phan Ham lugng (*)

Do lm% 53,00 Duong tong so% 20,32

P-carotene(pg/g) 177.059,82

(*) So lieu trung binh cua 3 ldn lap lai

4.2 Anh hudng cua pH va nhiet do thanh trung den chat lugng san pham pure

lekima

4.2.1 Anh hudng cua pH den chat lugng pure lekima

Mau sac va ham lugng P-carotene la yeu to quan trgng quyet dinh chat lugng san

pham puree lekima Vi vay ma mau ciia puree giu dugc mau vang ciia lekima cang

nhieu thi cang hap dan doi vdi ngudi tieu dimg pH ciia san pham khong chi anh hudng

true tiep den mui vi ciia san pham ma con quyet dinh den mau sac va ham lugng

p-carotene, do do can phai tim ra gia tri pH sao cho phii hgp vdi cac yeu cau tren la can

thiet cho san pham puree lekima

Bang 7: Ket qua thong ke anh hudng cua pH den chat lugng san pham

Ghi chii: So lieu trung binh ciia ba ldn lap lai, cac nghiem thuc trong cung mot cot co

cung ky tu a, b, c theo sau thi khong khac biet d mice y nghia 5%

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