Industrial Application of Ultrafiltration and Hyperfiltration in the Food

Industrial Application of Ultrafiltration and. Hyperfiltration in the Food and Dairy Industries. OLE JENTOFT OLSEN. DDS-NAKSKOV, Division of the Danis...
3 downloads 5 Views 977KB Size
3 Industrial Application of Ultrafiltration and Hyperfiltration in the Food and Dairy Industries Downloaded by UNIV OF CALIFORNIA SAN DIEGO on June 2, 2015 | http://pubs.acs.org Publication Date: May 27, 1981 | doi: 10.1021/bk-1981-0154.ch003

OLE

JENTOFT OLSEN

D D S - N A K S K O V , Division of the

Danish Sugar Corporation, 4900 Nakskov, Denmark

The development s t a r t e d by Loeb and S o u r i r a j a n i n 1960, has r e s u l t e d in something q u i t e d i f f e r e n t than d e s a l i n a t i o n of sea and b r a c k i s h water. I am q u i t e c e r t a i n that in those days they d i d not t h i n k of Feta cheese and low-alcohol beer. I have s e l e c t e d these products in order to show that membrane filtration is an accepted process in the food i n d u s t r y and not j u s t a pipe dream of the f u t u r e , on which we all based our hopes during the first years of the process. Feta Cheese Feta cheese o r i g i n a t e s from Greece, where it was originally produced from yew s m i l k . Today it is an important i n g r e d i e n t of the d a i l y d i e t in Southeast Europe and the A r a b i c c o u n t r i e s . I n these countries the m i l k production i s too low to s u s t a i n a l e v e l of s e l f - s u f f i c i e n c y w i t h t h i s type of cheese. Consequently s e v e r a l North European c o u n t r i e s , among them Denmark, have s t a r t e d a comprehensive production of Feta cheese f o r export purposes. The p r i n c i p l e of any cheese production i s that the m i l k p r o t e i n s are brought to an i n s o l u b l e form by means of enzymes, the soc a l l e d coagulation. Then the coagulated p r o t e i n i s s i f t e d from the components of the remaining m i l k . These components being water, s a l t s , l a c t o s e , and the whey p r o t e i n s lactalbumin and l a c t o g l o b u l i n . The whey p r o t e i n s c o n s t i t u t e up to 20% of the t o t a l p r o t e i n content i n m i l k . So these p r o t e i n s are wasted during the process. The p r i n c i p l e of cheese production by u l t r a f i l t r a t i o n i s that the p r o t e i n s are concentrated by UF i n the s o l u b l e form, i . e . bef o r e the enzyme treatment. The concentration i s c o n t r o l l e d i n such a way that the composition of the concentrate as regards f a t , prot e i n , s a l t s and water, i s equivalent to the composition of the f i n ished cheese. I t i s at t h i s point the enzyme i s added, causing the cheese to set i n the form, i n t o which i t has been poured. The whey p r o t e i n s , which were p r e v i o u s l y wasted during the t r a d i t i o n a l process, remain i n the f i n i s h e d cheese, r e s u l t i n g i n increased prod u c t i o n and t h e r e f o r e higher p r o f i t s . I s h a l l r e v e r t to t h i s l a t e r . '

0097-6156/81/0154-0027$05.00/0 © 1981 American Chemical Society In Synthetic Membranes: Volume II; Turbak, A.; ACS Symposium Series; American Chemical Society: Washington, DC, 1981.

28

SYNTHETIC MEMBRANES:

Downloaded by UNIV OF CALIFORNIA SAN DIEGO on June 2, 2015 | http://pubs.acs.org Publication Date: May 27, 1981 | doi: 10.1021/bk-1981-0154.ch003

Standardized

Ultrafiltration

Concentrate

H F A N D U F USES

Pasteurization

Pasteurized

39.5 % T S

Homogenisation

Milk

16.4 % Protein 17.8 % Fat

C u r d l i n g «- Rennet

12.5 % T S 3.4 % Protein 3.5 % fat

Permeate

S o u r i n g -• 2-3 % whey

5.5 % T S

Salting Final C h e e s e

+ salt

43.0 % T S 22.0 % Proteins 17.5 % Fat 3 % Salt

Figure 1.

The UF process for feta cheese

Milk tons/day Traditional method

300

Ultrafiltration method

300

Extra Yield

Fat tons/day

1.8

Cheese Sales price $/day tons/day 41

73,800

57

102,600

16

28,800

Fat addition Operation Costs

-=-6,700 -f 3,900

Profit by the UF process

18,200

Figure 2.

Economy in feta cheese production by UF

In Synthetic Membranes: Volume II; Turbak, A.; ACS Symposium Series; American Chemical Society: Washington, DC, 1981.

Downloaded by UNIV OF CALIFORNIA SAN DIEGO on June 2, 2015 | http://pubs.acs.org Publication Date: May 27, 1981 | doi: 10.1021/bk-1981-0154.ch003

3.

OLSEN

29

Food and Dairy Industries

Figure 3.

0rum Plant

. . . . . . Precipitation

~ . Unsoluble Drying—..... Milkprotem

in. »• Ultrafiltration

% r • Soluble Drying— .... Milkprotem Drying—Whey-Protein

-Ultrafiltration +

Diaf iltration

Sweet WheyUltraf iltration Permeate

Concentrate—Drying—Whey-Protein -Crystallization—Drying—Lactose

Acid Whey

Ultrafiltration

Acid

W

h

Drying— Protein

e

y

Figure 4. UF of whey

In Synthetic Membranes: Volume II; Turbak, A.; ACS Symposium Series; American Chemical Society: Washington, DC, 1981.

Downloaded by UNIV OF CALIFORNIA SAN DIEGO on June 2, 2015 | http://pubs.acs.org Publication Date: May 27, 1981 | doi: 10.1021/bk-1981-0154.ch003

SYNTHETIC MEMBRANES:

Figure 5.

Figure 6.

H F AND U F

Denmark proteins (outside)

Denmark proteins (inside)

In Synthetic Membranes: Volume II; Turbak, A.; ACS Symposium Series; American Chemical Society: Washington, DC, 1981.

USES

Downloaded by UNIV OF CALIFORNIA SAN DIEGO on June 2, 2015 | http://pubs.acs.org Publication Date: May 27, 1981 | doi: 10.1021/bk-1981-0154.ch003

3.

OLSEN

Food and Dairy Industries

31

Figure 1 shows, how u l t r a f i l t r a t i o n i s incorporated i n the process. Today a l l Danish d a i r i e s producing Feta cheese, w i t h one exc e p t i o n , base t h e i r production on u l t r a f i l t r a t i o n . The l a r g e s t of these i n s t a l l a t i o n s , b u i l t i n 1977, i s today t r e a t i n g 300,000 m e t r i c tons m i l k d a i l y . Investment i n UF p l a n t s amounts t o approx. 1 m i l l . $. The economical s i d e of the matter i s as f o l l o w s (see Figure 2 ) . Indeed, a notable increase i n p r o f i t s as a r e s u l t of the work c a r r i e d out at UCLA i n 1960 and followed-up by DDS i n 1965. Figure 3 shows the DDS UF-plant at the above mentioned Feta cheese f a c t o r y . I t comprises a t o t a l of 20 DDS UF modules, type 35, each w i t h 27 m^ (approx. 297 f t ^ ) membrane area. The membrane a p p l i e d i s o f s y n t h e t i c m a t e r i a l w i t h a nominal c u t - o f f value o f 2Q,000. The p l a n t can operate round the c l o c k , and the c l e a n i n g time i s approx. 2 hours every 24 hours. The c l e a n i n g i s c a r r i e d out w i t h a s o l u t i o n of hot 0.5% sodium hydroxide, f o l l o w e d by a s o l u t i o n of hot 0.3% n i t r i c a c i d , and s t e r i l i z a t i o n i f necessary w i t h C l ^ . The membrane l i f e time i s approx. 1 year. Proteins The i n t r o d u c t i o n of membrane f i l t r a t i o n i n connection w i t h d a i r y production has r e s u l t e d i n a wide range of new p r o t e i n enr i c h e d products of which the whey p r o t e i n s have a t t r a c t e d the l a r g e s t amount of a t t e n t i o n . F i g u r e 4 shows a few of the d i f f e r e n t products which are produced today. The l a r g e s t d a i r y company i n Denmark, c a l l e d "Dairy Denmark" i s , as f a r as I know, the most p r o g r e s s i v e one i n the world today w i t h regards t o the production of whey p r o t e i n s by means of u l t r a f i l t r a t i o n . Figure 5 i s a photo of a q u i t e new p r o t e i n f a c t o r y , c a l l e d "Denmark P r o t e i n s " , whose s o l e purpose i s t o u l t r a f i l t r a t e 1,000 m e t r i c tons of whey per day f o r the p r o d u c t i o n of approx. 10 m e t r i c tons pure whey p r o t e i n i n powder form, and as a by-product approx. 50 m e t r i c tons of l a c t o s e . The p l a n t was put i n t o o p e r a t i o n i n May, 1980. Up t i l l now nothing has been r e l e a s e d concerning the t o t a l economy of the p l a n t , but I am convinced that "Dairy Denmark" have made sure that the economy i s sound. The essence of t h i s p l a n t i s of course the UF p l a n t i t s e l f , which i s shown i n Figure 6. I t i s a DDS plant of the same type as at the Fe£a cheese d a i r y , c o n s i s t i n g of 45 modules, type 35, each w i t h 42 m (452 f t ^ ) membrane area. The p l a n t i s f u l l y automatic, c o n t r o l l e d by micro processors and i n t e g r a t e d i n a s u p e r i o r t o t a l c o n t r o l of the whole f a c t o r y . The p r i n c i p l e of the p l a n t c o n s t r u c t i o n i s shown i n F i g u r e 7. I f a higher p u r i t y i s d e s i r e d than achieved by normal u l t r a f i l t r a t i o n , water may be added during the process ( d i a f i l t r a t i o n ) . I n t h i s way more i m p u r i t i e s w i l l pass through the membranes.

In Synthetic Membranes: Volume II; Turbak, A.; ACS Symposium Series; American Chemical Society: Washington, DC, 1981.

32

SYNTHETIC MEMBRANES:

f-Preconcentration—j

H F AND U F

USES

-

Diafiltration—j— com!. 1

Feed _tank

Downloaded by UNIV OF CALIFORNIA SAN DIEGO on June 2, 2015 | http://pubs.acs.org Publication Date: May 27, 1981 | doi: 10.1021/bk-1981-0154.ch003

module Booster pump

Feedpump seo^p

£ nil f If Water

Figure 7.

Figure 8.

Continuous UF Plant (principle)

Brrup, HF of whey in Denmark

In Synthetic Membranes: Volume II; Turbak, A.; ACS Symposium Series; American Chemical Society: Washington, DC, 1981.

Product tank

3.

OLSEN

33

Food and Dairy Industries

Downloaded by UNIV OF CALIFORNIA SAN DIEGO on June 2, 2015 | http://pubs.acs.org Publication Date: May 27, 1981 | doi: 10.1021/bk-1981-0154.ch003

tons vapour kg fuel kWh per ton water removed Evaporation of whey 5 % TS - 20 % TS

0.18

13.8

53.2

Hyperfiltration of whey 5 % TS — 20 % TS

6.8

Saving in %

88

Figure 9.

Figure 10.

HF of whey

HF plant for removal of alcohol

In Synthetic Membranes: Volume II; Turbak, A.; ACS Symposium Series; American Chemical Society: Washington, DC, 1981.

Downloaded by UNIV OF CALIFORNIA SAN DIEGO on June 2, 2015 | http://pubs.acs.org Publication Date: May 27, 1981 | doi: 10.1021/bk-1981-0154.ch003

34

SYNTHETIC MEMBRANES:

H F AND U F

Figure 11.

Development center in the dairy industry (outside)

Figure 12.

Development center in the dairy industry (inside)

In Synthetic Membranes: Volume II; Turbak, A.; ACS Symposium Series; American Chemical Society: Washington, DC, 1981.

USES

Downloaded by UNIV OF CALIFORNIA SAN DIEGO on June 2, 2015 | http://pubs.acs.org Publication Date: May 27, 1981 | doi: 10.1021/bk-1981-0154.ch003

OLSEN

Food and Dairy Industries

Figure 13.

DDS-NAKSKOV

In Synthetic Membranes: Volume II; Turbak, A.; ACS Symposium Series; American Chemical Society: Washington, DC, 1981.

36

SYNTHETIC MEMBRANES:

H F A N D U F USES

The product composition, i . e . the p r o p o r t i o n between p r o t e i n and l a c t o s e i n the f i n a l product, may be c o n t r o l l e d from the cent r a l c o n t r o l room. Thus the f a c t o r y i s able to produce p r o t e i n powder w i t h compositions v a r y i n g from approx. 35% p r o t e i n of t o t a l s o l i d s to approx. 85% p r o t e i n of t o t a l s o l i d s . The f i r s t ment i o n e d i s a product w i t h a composition l i k e cheap skim-milk powder, whereas the l a t t e r i s an expensive product used f o r babyfood and d i e t e t i c food.

Downloaded by UNIV OF CALIFORNIA SAN DIEGO on June 2, 2015 | http://pubs.acs.org Publication Date: May 27, 1981 | doi: 10.1021/bk-1981-0154.ch003

Concentration of Whey Today d i r e c t c o n c e n t r a t i o n of whey i s known and accepted as an exceedingly a t t r a c t i v e supplement o r a l t e r n a t i v e to evaporation. F i g u r e 8 shows a t y p i c a l DDS RO plant c o n s i s t i n g of 14 19 m (205 f t ) modules equipped w i t h membranes of c e l l u l o s e a c e t a t e , not v e r y d i f f e r e n t from those developed i n 1960. Around 6 m e t r i c tons are t r e a t e d d a i l y . F i g . 9 shows a comparison of the energy consumption by evap o r a t i o n and h y p e r f i l t r a t i o n (also c a l l e d reverse osmosis). 2

2

Removal o f the A l c o h o l i n Beer A new f i e l d i s the removal of a l c o h o l i n beer by means of h y p e r f i l t r a t i o n . "De forenede B r y g g e r i e r " - perhaps b e t t e r known under the names Tuborg and C a r l s b e r g - have developed a process f o r removal of the a l c o h o l i n beer by means of the DDS h y p e r f i l t r a t i o n system. The advantages w i t h t h i s are that the a l c o h o l percentage may be adjusted according to the d i f f e r e n t marketing areas - without having to change the brewing process. Figure 10 shows a DDS p l a n t f o r the h y p e r f i l t r a t i o n of Beer. DDS Development I n order to emphasize how much we expect of the f u t u r e DDS has b u i l t a new d a i r y f o r development purposes. The main o b j e c t s being product and process development based on membrane f i l t r a t i o n i n the food i n d u s t r y . The d a i r y i s shown i n Figures 11 and 12. DDS-Nakskov F i g u r e 13 shows the DDS p r o d u c t i o n plant i n Denmark f o r membrane f i l t r a t i o n equipment. Around 250 people are working i n t h i s ever expanding company. RECEIVED

December 4, 1980.

In Synthetic Membranes: Volume II; Turbak, A.; ACS Symposium Series; American Chemical Society: Washington, DC, 1981.