STUDIES ON THE EFFEfX OF CamANSI I CnRZrs JUICE ON THE PRESERVATION OF SUME OR SHRIMPS { GENUS PEWUS )

S.V. Bersamin. AS. Legaspi and N.G. Macaiincag

ABSTRACT TWOsets e xperirnents (packing in c&mansi juice ice, dipping in calarnansi bite and packing in ordinary ice) conducted to determine the efficacy of calamansi (atype of citrus fruit simjrar to lemon ) juice in prolonging the freshness of shrimps, show that calamansi juice inhi bits the growth of microorganisms on the flesh of shrimps, retards proteolytic decomposi- tion which is usually characterized by the development of fishiness,blackening of the head and tail and loosening of shells, and inhibits devdopment of strong off-odors. ZNTRODUCTION is widdp cultivated in the Philippines and One of the major problems ic the com- bears fruits the year round. At certain sea- mercial handling of fishery prdccts is the sons it rows in abundance and becomes very prevention of the deteriorative changes which cheap. It is readily available in most markets make them unacceptabie to the discrimina- and stores in the Ybilippincs. ting consumers. Fish starts to deteriorate Analysis of calamansi (per 100 grams) :* immediately after catching, and no method Edible portion, 40% of preservation has yet been devised ta keep Moisture, g 89.9 Fat, g 0.6 them absolutely fresh. For this reason it is Carbohydrates,g 0.3 necessary that some precautionary measures Ash, g 8.9 be taken 13order to slowdown ihe deteriara- Calcium, mg 22.0 in tive changes that take p:ace fish and other Phosphorus, mg 12.0 fishery products. Deterioration m fish is Iron, mg 1.5 primariIy due to tnzyrnes and bacteria pre- Sodium, mg 2.4 sent in them. Among the various methods Potasium, mg 800.0 of preservation, icing is the most practical Thiamin, mg 0.02 especially if the fish is to be sold as fresh. Rivotlavin, mg 0.01 However icing preserves fishery products Niacin, mg 0.01 for only a limited time, especially when fish Ascorbic acid, mg 40.00 is subjected tcl too much handling and trans- Citric acid 3.6- 3.7 g./100 g. of juice- porting. The Philippine calamansi is the coan- The accompanying experiment aims tu terpart iemon in other countries. Cab- improve the icing method now being em- mansi and lemon have more or less the same ployed by commercial handlers of fishery pro- acid contents ( ascorbic and chic ) which arc ducts, through the use of an inexptnsivr responsible for their preservative tEect. Cilw microcarpa or native frait, Bungt Czfnu 111 a detailed study on the chemistrY i~cornmonlyknown as cahmansi. The tree ------of shrimp whicb was published by the Sunkist * Data mppliPliHI1 by the Fwd acd Nutritiw Genre: and the Bu Growers, Ontario, California ( " The Effect to have an inhibitory effect on the strains of of Lemon Juice in Shrimp Processing"), the Psdmwws sp. Growth of microorganisms in factors associated with the aging of shrimp a medium containing ascorbic acidis inhibited and the breakdown of shrimp tissues result- by the increase in acidity and release of hy- ing in a strong fishy ammoniacal odor were drogen peroxide in the medium. determined. The properties of lemon juice Fauikner et a1 ( 1954) state that " black which make it an effective preservative were spots " is a condition in shrimp characterized explored and concf usions were made that : by the development of a black coloration lemon juice is an. effective anti-oxidant and which starts from the head and spreads to a bufiered acidic system capable of great She tail, where it forms black bands outlining dilution; it inhibits the growth of microor- the sections of the tail region. Unless they ganisms which affect shrimp flesh and that iced immediately, blackening may begin lemon juice retards the enzymatic action are within a few hours after death of the shrimps. producing the darkening of sea-foods as- However, breakdown. even with continuous icing, black- sociated with proteoly tic Other enhg may be far advanced before the catch conclusions were: certain ingredients in lemon can be marketed. This is a predicament juice are good sequestering agents and will usually encountered in the handling of suppress the effects of metals such as iron shrimps in the Philippines. and copper in promoting unwanted chemical reactions in sea foods; lemon juice neutralizes Hardening and darkening of the cuti- or keeps lobster or shrimps from becoming cles of lobsters were due to the enzyme tyro- alkaline thus preventing the disagreeably sinase. Fieger ( 1951) presented the first strong '' fish-like " odors from developing; evidence for the enzymatic nature of the certain combinations of ingredients in lemon blackening reaction in shrimps. Fieger es- juice contribute to the freshness and flavor tablished that bacteria was not instrumental enhancement in seafoods; and that lemon in bringing about blackening. If it could be juice has a very low surface tension which definitely established that blackening in makes possible rapid penetration in solid shrimp is due to the enzyme tyrosinase, mea- foods and increase its effectiveness. sures found effective ininhibiting the enzyme in other sources might be adopted to control An experiment done by Luther and the black spots in shrimps. The work herein Grawall ( 1946 ) reveaIed that citric acid and presented was undertaken to obtain further ascorbic acid added to apples retained their evidence for the enzymatic nature of the natural color. The experiment also revealed black spots and to explore methods of retard- that citric acid inactivates the enzymes of ing the reaction in shrimps. the fruit. The combined use of citric and ascorbic acids produced improved anti-axi- It is surmised that calamansi which is dant properties over citric acid alone. This a cheap source of ascorbic and citric acids, natural combination of citric and ascorbic hence a reducing agent, would be a controling acids are found in the local calamansi. measure for the retardation of darkening in shrimps. Refrigerated shrimps may be able In another experiment conducted by to retain their quality when covered by lemon Watts and Techmann ( 1952 ) on the use of juice solutions. From the work of Faulkner ascorbic acid on meats, it was revealed that ( 1954 1, it was found that ascorbic acid and the addition of ascorbic acid to refrigerated sodium ascorbate in concentrations ranging ground meat resulted in the " brightening I' from 0.05% to 0.5% were effective in pre- of the meat surfaces after a few days venting darkening of cuticle extracts in the storage in the refrigerator. presence of added phenolic substrate as well Costilow ;1955 ) states that ascorbic as inhibit blackening of beads or whole acid in 0.1 per cent concentration was found shrimps as long as thelatter remainin solution. In another instance, lowered pH of shrimp toughening effect, which was noticed after medium decreases the activity of the enzyme the seventh day of observations of calamansr tyrasinase. ice on the shrimp, the confirmatory expcrr- was The foregoing experiments tend ta ment altered. prove that cal smansi juice lengthens the Experimental groups for tbe confirma- f redmess of refrigerated shrimps. tory experiment were the following : Batch No. I was packed in ordrnar y ice EXPERIMENTAL METHODS Icontrol ). Seven hundred pieces of ripe calamansi BatchBo. 2 was dipped ita a I: 30 cal- fruits and 4 kg. of shrimp or suabe (Pnraeur) amansi solution and packed in were purchased from a local market. The ordinary ice. juice was extracted from the fruits and the Batch No. 3 was dipped in a 1 :20 cai- various concentrations needed in the experi- amansi sdution and packed in ment were made using tap water as the dr- ordinary ice. hent. Calamansi ice was prepared by mixing Batch No. 4 was d~ppcdin a 1 : 10 cal- one part of caiamansi juice to forty parts of amansi solution and packed in water and placed in a deep freezer where tne ordinary ice. solution was converted to ice. The shrimps TBC were washed thoroughly with tap water, The and organoleptic observations on raw arid cooked samples were made dzily drained and divided into four batches, and the on the experimental batches. The shrimps initial total bacterial count taken for each used in tbis experiment having been purchas- batcha The first batch was packed in ordinary ed from a local market were not in a very ice to strve as control. The second batch fresh state. The samples were refrigerated was packed in calamansi ice ( 1 : 40 calam- at a temperature rqgiog from-5.0% to-8.0'C. ansi solution frozen into ice ). The third batch Ice was replaced when melted. Proximate was dipped in calamansi solution ( 1 : 20 ) for chemical analyses were madc on the samples a period of 10 minutes and packed in ordinary before and after the completion of the ex- ice. periments. The total bacterial count ( TBC ) of the of different experimentaf batches were taken For purposes idcntificataon a code was at periodic inter vds. Organoieptic observa- made to represent the various sample tions on raw and cooked samples were also batches used in the two experiments: madc daily throughout the period of the in- Experiment 1 Experiment 2 vestigation. Batch No. 1 C C Two qets of experiments were made. Batch No. 2 CI C, The Grst aimed at finding the concentration Batch No. 3 D %, of calamansi solution for dipping and the Batch No. 4 DCI proportioc of caiamansi juice in the prepara- C,* tion of calamansi ice which would be most effective in preservin~ the freshness af RESULTS .4ND DISCUSSIONS shrimp. The second experiment served to The resu1:s art shown in Tables I, 11, confirm the result of the first. Due to the I11 and EV, and Fig. 1 and 2. TABLE: I The Effect qf DiflPPBngin Crrimrraffsi Sdlrtimr d thUpe of Cabmmi Ice arr the TdBatd Coltrrt and Physical

rH of melted ice RAW

As it comes 35,125 Brownish Loose Good (fresh odor) from the markel

Immediately af. I Brownish Firm Good ter dipping for (improved) 10 min. in cala- madsolution

Controt 7.8 120,072 Brownish Firm Smells Iike sea / water. CI 5.0 Good D 7.6 Good DCI 5.0 Odor of calamansi perceived

Control I Brownish Firm As of fresh shrimp CI P* I?

D I¶ I# DCI *I I?

Control Head portion Firm As of fresh shrimp becoming dark CI Brownisb D DI DCI PI

Control 119,650 Bead portion Firm As of fresh shrimp becoming dark 77,310 Brownish 115,170 I* 100,330 $9

Control Head portion Sheli becon Fishiness perceived becoming black ing iose CI Brownish Firm As of fresh shrimp D ;hell becom Fishiness perceived ing loose DCI Firm As of fresh shrimp lumber of ays RAW Colm Terture ardor Control Soft Fishiness more darker pronounced Tough Shrimp portion no longer perceived Firm Fishiness is per- ceived DCI Tough Shrimp odor no longer perceived Control 107,101 Head portion Soft Ammoniacd odor darker perceived. CI 81,242 Pinkish Tough Shrimp odor no longer perceived D 8.4 1 27,967 1 Brownish Firm Ammoniacal odor perceived DCI 4.4 1 34,144 / Pinkish Tough Shrimp odor no longer perceived Control Soft Ammaniacal odor becoming dark developed CI Tough Odorless D Firm Ammoniacal ador developed DCI 4.2 1 128,807 1 Bluish Tough Odorless -- Control 8.5 7,543,800 Head portion Soft Ammoniacal odor becoming dark more intense 4.0 Hot sampled Bluish Tough Odorless 8.5 565,785 Brownish Firm Ammoniacal odor perceived DCI 3.8 Not sampled Tough OdorIess Control 8.6 8,045,450 Soft Ammaniacal odor blacker more intense 4.0 Not sampled Bluish Tough Odorless 8.5 2,171,700 Head portion Soft Ammoniacal odor becoming blacl perceived DCI --3.8 Not sampled BItrish Tough Odorless Control 8.6 49,277,600 Bead portion Soft Ammoniacal odor blacker perceived CI 4.0 Not sampled Bluish Tough Odorless D 8.5 7,610,475 Head portion Soft Ammoniacal odor becoming blacE perceived DCI 0.8 Not sampled/ Bluish Tough Odorless Control 47,717,400 Head portion Soft Ammoniacal odor 1 - DIaskrr more intense CI Not sampled Bluish Tough Odorltss D 28,862,000 I Besd portion Soft Ammoniacal odor becoming blad more intense DCI Not sampled Bluish Tough Odorless TABLE I1

Initial

( Control ) C

( Dipped ) I)

DCX RAW

As it came f mm 1s of fresh sbrimr Firm As of fresh Shrimp the market. Brownish block I 9s of fresh shriml: Firm As of f r esb shrimp Brownish black I I ?

?1

I*

Bromi8h black Firm 1~sof fresh abrinp

*I

I*

I*

Brorrni sh black Firm A& of fresh shrimp s* 1) I? I* *I #I P*

Bead Wloa Firm of fresh ahrimg slightly pinkish Brownish black I*

ID

Pinkish, head por. tion with bhck spots Brownish black

I* *a

Pinkish, badpor. Soft Fiainsss tion with bhck perceived spots #r wr Firm IAS of fresh rhrimp i *I *I . . Number of days Sdc.rctd RAW Texture

9 Pinkish, head por, Soft, shell Ammoniacal odor tion with black becoming perceived spots loose 9 I* II 9 Read portion . Firmness pinkish kish ceased

9 I¶

Pinkish, head por Soft, she11 Ammoniacal odor tion with black becoming perceived spots Ioose

I* slight 1y"pinkish Slightly sofl Fair

I* I* **

Pinkish, head gor Soft, shells Ammoniacal ador tion with black becoming more pronounced spots hose Head portion wit! Soft, shells black spots - . becoming Slightly pink Ioose Soft Fair

19 II

f inkish, head por Soft. shells Ammoniacal odor pling tion blackish f oosen ed more pronounced

*I is ?I 8.6 ?I >* >I

*I 'I tl

Pinkish, head por Soft, shells Ammoniacal odor tion blackish loosened more pronounced

?I I1

I, *I

l* ?I

Pinkish, head par soft,shells Ammoniacal odor tion blackish loosened more pronounced >I 8.7 No Sam- ?I I? H I¶ 8.7 pling I? I* 19 8.6 I>

Pinkish, head por Soft, shells Ammoniacal odor tion blackish loosened more pronounced ?I I, ?I YI ' YY ,I *I I# ?I

Experiment 1 showed the effect of dip- and that of the CI0 batch went down to 11.30%. ping shrimps in 1 :20 cabmami solution and No toughening effect was observed in a11 the the use of caiamansi ice for packing on the samples. preservation of shrimp. The length of the experimental period was 16 days afterwhich Calamansi juice in any form applied to a proximate chemical analysis war made on shrimps was capable of lowering the total all the samples. The contrd samples showed bacterial count as seen in the accompanying lips of de tcrioration such as blackening of tables and graphs. The characteristics of the head and tail, loosening of shells, and spoiIagc in the raw samples wcre still evid- development of fishiness characteristic of end after they had been cooked. abrimp spoilage after the third day. Tbt Orgaaoltptic examination of cooked protein content showed a marked reduetian samples of Experiment 1 showed no difference from 19,5t% to 10.20% Signs of spoilage in taste, color, tcxtnra and odor until the fifth were evident on the samples dipped in 1: 20 day of observations, after which the head calamansi sdution and packed in ordinary portion of the control samples developed ice after the eighth day. The protein content blackish dJscoloration. However the tast a, was reduced to 10.68%. The samplts which texture and odor were norma Hy maintained. were packed in calamami ice and those dipped On the eight day, samples that were packed in 1 :20 calamansi solution and packed in cab in ordinary ice ( dipped and not dipped in amansi ice showed no Bigns of spoilage up to calamansi aoIurion) became twgh, last the the seventh day. On the eighlh day, the shrimp taste and calamansi taste was ptr- shrimp meat was observed to toughen and to ctived. Samples that were dipped in calama- turn pink. The normal shrimp odor was no nsi solution packed in ordinary ice maintained perceived. On longer the ninth day deterior- normal characteristics within a period of 12 ative changes began to taka place and on tbe daya. sixteenth day, they were positively spoiled. The protein content was more or lers main- Similarly, another orgaooleptic arami- tained. nation made on cooked samples of Experim- ent 2 showed no difference in taste, odor, color Experiment 2 showed the effect of dif- and textnre within a period of 8 days. On the ferent kinds of dips without packing In cal- ninth day the bead portion of the control amansi ice on shrimps. This procedure was samples and samples dipped in 1 :30 cal- done to eliminate the toughening effect of amansi aolutioa developed binckish discolora- cahmansi ice on shrimps with the hope that tion aad the taste became flat. Samples dip the protein content would also be maintained. ped in 1 :20 and 1 :10 cabmansi solution The control samplca showed evidences of maintained their normal characterintics wit- spoiiage after the third to tie Hth day and hin f 1 days. On the 15th day aH samples the protein content was reduced from 18.62% tasted flat with signjficant ofi-odors. to 9.11%. The samples dipptd in 1: 30 cal- amansi solutian wcre considerad fresh up lo SUMMARY AND CONCLUSIONS the 6th day. The protein content was re- Two experiments were conducted to duced from 18.62% to 9.0% Those samples determine the efficacy of calamansi juice in which received to 1 :20 and 1 : 10 dips were prolonging the freshness of shrimps. The considered fresh up to t be eight day. On the first consist ad of dipping the shrimp samples ninth day deteriorative characteristics began with a 1: 20 calamansi solution and packed to be evident such as pink discoloration of with calamansi ice formed by freezing 1 :40 the flesh, development of black spots cn the calamansi soiution. The second consisted of head and tail, loosening of shells and the ds- dipping the shrimp samples in different con- velopment of an ammoniacal ador. Protein centrations of calamansi solution and then content in theCa batch was reduced to9.14S packed with ordinary ice. In Experiment I, the controls were for short periods. Calamansi juice, because considered fresh up to the third day while of its ascorbic and citric acid content was those wbich were dipped in a 1:20 calamansi capable of retaining and maintaining the solution and packed with ordinary ice showed physical freshness and protein content of tile dgna of deterioration, blackening of the head shrimp. However, the latter is dependent and tail, loosening of shells and development upon the treatment to which the shrimp sam- of a fishy odor, characteristic of shrimp spoi- ples are subjected. Calarnansi juice inhibits lage after the eighth day. A proximate che- the growth of microorganisms on the flesh of mical analysis revealed that the protein con- shrimps. Results of the experiment indicate tent war reduced to almost one half of the that there was a significant reduction in the initial protein content. The samples which TBC of'those samples dipped in calarnansi were packed with calamansi ice together with soIution. ProteoIytic decomposition which those wbich were dipped in a 1:20 edamassi is usually characterized by the development solution and then packed with calamansi ice of fishiness, blackening of the head and tail showed no signs of deterioration up to the and loosening of shells was retarded. The seventh day; however, after the eighth day, acid content of calamansi juice neutralizes there was pink discoloration and toughening the flesh of shrimp and prevents the develop of the flesh. This characteristic was also evi- ment of strong off odors. Improvement in dent in the cooked samples. After this pe- the flavor was noted in the cooked samples. riod, the shrimp odor wasno longer perceived. Enzymatic activity was retarded because cal- However, the protein content was maintained. amansi juice has the property of lowering All the samples which received a calamansi the pH. treatment, in the form of a dip, of calamansi ice and a combined treatment of bot h, showed REFERENCES a reduced TBC as compared with the control samples. Campbell, L. Jr. and O.B. Williams I 1952) : Experiment 2 was planned to eliminate Bacteriology of Gulf Coast Shrimp. the toughening e%ect of calamansi ice. Three BacteriologicaI chemicaI and organo- batches of shrimp samples were dipped in leptic changes with ice storage. Pod different concentrations of calamansi solu- Techmdagy, 6 :125- 126. tion. They were all packed with ordinary ice. Costillow, R.M. et dal.( 1955 ) : Interaction bet- The control samples showed signs of deterio- ween ascorbic acid and psychrophi1ie ration after the third to the fifth day. Those bacteria associated with the discolora- dipped in a 1 :30 calamansi solution indicated tion of prepackaged beef. Food Tech signs of spoilage after the 6th day and those logy, 9 :560-563. which were treated with 1:20 and 1: 10 so- Faulkner, M.B. et al. ( 1954 ) : Enzymatic dark- lutions, after the eighth day. No toughening ening of shrimps. Food Reremch, 19: was observed in a11 samples. these 302-310. In all cases, the TBC of samples treated 1955 was et al. ( ) : Deteriorative with calamansi juice Iower than those changes in frozen shrimps and their were n& which treated. Proximate chemical inhibition. Food Technology,9 : 632.635. analysis showed that there was a loss in tbe protein content in a11 shrimp samples; how- Luther, H.B. and G.O. GrawaI1( 1946 ) : As- ever the samples treated with higher con- corbic and citric acids prevent brown- centrations of the calamansi solution showed ing of cut fruits. Food Industries, 18: 690. a lower rednction of protein content. Watts, B.M. and B. Techmann (1952) : Ascor- The use of calamansi-ice is more eflec- bic acid and meat color. FdTechndogy, tive than the use of ordinary ice, if applied 6{5): 125-126.