日本調理科学会誌Vo1.40,No.4,231～238(2007)〔Article〕

Some fine aspects and historical background of "Balut" and "Penoy", boiled incubated fertilized and unfertilized duck

Norlita Sanceda Kumiko Ueda Julia Ibenez Emiko Suzuki Midori Kasai Keiko Hatae

The historical background of "balut" and "penoy", boiled fertilized and unfertilized incubated duck eggs, respec- tively, was investigated and some chemical aspects of this product were studied. Samples were commercial boiled incubated fertilized ("balut") and unfertilized ("penoy") eggs from the and eggs purchased in Ja- pan and incubated in the university laboratory. Result of the search revealed that "balut" and "penoy" making is not native to the Philippines. Chinese traders and migrants have brought the idea of eating fertilized duck eggs to the Philippines around the 17thcentury. However, the knowledge and craft of balut-making has been localized by the "balut" makers (mangbabalut). To date, "balut" production has not been mechanized in favor of the traditional production by hand. The total FAA content of the incubated samples was higher than that of the non-incubated samples. Taurine significantly increased in both the unfertilized and fertilized samples, thus has a positive impact on the nutritive value of the product. It was observed that after boiling, a large amount of drip was present in the whole incubated fertilized eggs, less in the unfertilized and hardly any in the non-incubated ones.

Key word : "Balut", "Penoy", incubated duck eggs, free amino acids

Duck raising is a lucrative industry in the Philippines. Introduction Its important egg products, "balut" and "penoy" (boiled The food culture of different countries varies and fertilized and unfertilized incubated eggs) , respectively, should be respected as it is because it represents a part are known throughout the archipelago for their delicious of one's total culture. Recognizing other countries culture flavor and nutritive value (AICAF, 1998). In the Philip- is one way of bridging the gap among countries. This ar- pines, unlike chicken eggs, it is uncommon to eat cooked ticle will give an enlightenment of a short historical back- fresh duck eggs because of their characteristic odor or ground, and some aspects of "penoy" and "balut", boiled non-palatable taste. Therefore, duck eggs are incubated unfertilized and fertilized incubated duck egg, respective- at 40°C necessary to develop embryos, or salted or pre- ly, egg products in the Philippines. "Penoy" and "balut" pared in various ways. In the Philippines, ducks are usu- are popular egg products in the Philippines, consumed in ally fed indigenous materials so that the nutrition compo- as a in meals or snacks and in Southern sition of the eggs may vary to some extent. Duck raising as food or medicine (Shu, 2004) , but they are not is recommended in bay towns where abundant supplies eaten in neighboring countries in , nor in of fresh water snails which make good duck food are other parts of the world, probably due to lack of informa- available. It becomes a family industry to some and a tion about the products or due to the existence of laws or hobby to others. regulations regarding the product. The popularity of What is "balut" and "penoy" ? these egg products in the Philippines has been increasing these years where the market price is affordable for the Meat and egg-type ducks are raised in the Philippines masses. Foreigners also enjoy the products with beer, es- but the latter is more popular. Mallard duck locally pecially in the open space at night when the temperature known as Pateros itik (Anas platyrynchos) is commonly gets cooler. used by duck farmers in the Philippines. The eggs from this duck are processed to "balut", "penoy" and salted * Ochanomizu University eggs. Fig. 1 shows the "balut" at different stages of incu- ** Western Visayas College of Science and Technology *** Wayo Women's University bation. A delicacy of Southeast Asia and especially of the § inquiry Faculty of Human Life and Environmental Science Ochano- Philippines that commands a good price, "balut" is a mizu University boiled fertilized duck egg incubated for about 18 days 2-1-1 Otsuka, Bunkyo-ku Tokyo 112-8610 TEL 03 (5978) 5765 FAX 03 (5978) 5760 with a developed embryo inside that is boiled and eaten

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Fresh 7 days

14 days 17 days

21 days

Fig. 1 Different stages of incubation of "Balut"

"balut" in the shell. An interview with a traditional "balut" maker vendors and they come together with other native showed that the best "balut" which is known as "balut sa snacks (Davidson, 1999). The popularity of this egg prod- puti" is made by allowing the eggs to incubate for about uct has been increasing these years especially with stu- 18 days, but beyond that the chick will be too large for dents who burn their midnight candles during their prep- leisurely consumption. Duck eggs that are not properly aration for university examinations. The product gives developed after nine to twelve days are sold as "penoy", them enough energy to combat the energy loss during which look, smell and taste similar to a regular hard- their struggle. . These eggs are originally unfertilized, there- History fore incapable of developing into chicks. After incubation, "Balut" making is not nati the hardens and the softens and becomes ve to the Philippines. A simi- watery after boiling. Popularly believed to be an aphrodi- lar preparation is known in China as maodan (Chinese siac and considered a hearty snack, "balut" and "penoy" ; Pinyin: mdodân ; literally "hairy egg"), and Chinese are mostly sold by street vendors at night. Due to their traders and migrants are said to have brought the cus- high protein content, they are known as an energizer to tom of eating fertilized duck eggs to the Philippines those who need strength or are complimentary to the around the 17th century. However, the knowledge and consumption of beer. They are peddled every evening by craft of balut-making has been localized by the balut

10 (232) Some fine aspects and historical background of "Balut" and "Penoy", boiled incubated fertilized and unfertilized duck eggs makers (mangbabalut) • To date, "balut" production has tion period of 17-19 days was about 70% while infertile not been mechanized in favor of the traditional produc- eggs and dead embryos were about 18% and 11%, re- tion by hand. Although "balut" is produced throughout spectively. the Philippines, balut-makers in Pateros are renowned Cuisine for their careful selection and incubation of the eggs. Fer- tilized duck eggs are kept warm in the sun and stored in The recipe in the Philippines for "balut" used to be lim- baskets to retain warmth. After nine days, the eggs are ited to boiling and it is most often eaten with a pinch of held to a light to reveal the embryo inside. Approximate- salt, though some "balut" eaters prefer chili and vinegar ly eight days later the "balut" are ready to be cooked, to complement their egg. The eggs are savored for their sold, and eaten. Vendors sell cooked "balut" out of buck- harmony of textures and flavors the broth surrounding ets of sand, used to retain warmth, and are accompanied the embryo is sipped from the egg before the shell is by small packets of salt. Uncooked "balut" are rarely sold peeled and the yolk and young chick inside can be eaten. in Southeast Asia. In the United States, many Asian mar- All of the contents of the egg are consumed with the ex- kets occasionally display uncooked "balut" eggs, though ception of a hard white chunk (the bato or "rock") that is their demand in North America is not very great. The found in the bottom of the egg. "Balut" have recently en- cooking process is identical. tered higher cuisine by being served as appetizers in res- The Chinese traders who eventually settled in the taurants : cooked adobo style, fried in or even town introduced. the most famous balut industry. The used as filling in baked pastries. Fresh duck eggs are also name Pateros came from the Tagalog words "pato" mean- used to prepare a dessert called leche "flan" (egg cus- ing the duck that lays eggs for balut making. Balut mak- tard) or beaten and fried, similar to , and ing is a major tourist attraction in Pateros and shares served with a vinegar dip. "Penoy" looks, smells and taste about 23% of the whole Pateros industry. It is a place sit- similar to a regular fresh hard-boiled egg. uated in the southeast of Manila, the smallest of the sev- Approximately eight days after incubation, the "balut" enteen cities and municipalities comprising the Metropoli- are ready to be cooked, sold, and eaten. Vendors sell tan Manila. Pateros before 1,700 was only a barrio of cooked "balut" out of buckets of sand, used to retain Pasig called "Aguho" or "embarcadero". Aguho was de- warmth, and are accompanied by small packets of salt. rived from the name of numerous shady trees planted Uncooked balut are rarely sold in other Southeast Asian along the Pateros River, while "embarcadero" means a countries. In the United States, many Asian markets oc- small port. As a port, Pateros was the focal point of trade casionally carry uncooked "balut" eggs, though their de- and commerce not only for the entire municipality of Pa- mand in North America is not very great. The cooking sig but also for the neighboring towns. It also served as process is identical to that of hard-boiled chicken eggs. harbor for the Malay, Chinese, Swedish and Indian ves- The period for the incubation of the egg before it can sels that periodically called to disembark merchandise be cooked is a matter of colloquial preference. In the Phil- and to engage in commerce. ippines, the perfect "balut" is 17 to 18 days old, at which Ducks can be raised for meat purposes and egg pro- point it is said to be "balut sa puti" ("wrapped in white"). duction. Meat-type ducks are popular in China, Japan, The chick inside is not old enough to show its beak, feath- South Korea, Vietnam and Thailand. In Bangladesh and ers or claws and the bones are not fully developed. The Indonesia, egg production from egg-type ducks is preva- Vietnamese prefer their "balut" matured from 19 days up lent. The meat and egg-type ducks are raised in the Phil- to 21 days, when the chick is old enough to be recogniz- ippines but the latter is more popular. Mallard duck local- able as a baby duck and has bones that are firm enough ly known as Pateros itik (Anas platyrynchos) is but tender when cooked and is eaten with coriander or commonly used by duck farmers in the Philippines. The other spicy leaves. eggs from this duck are processed to "balut" and salted Experimental design eggs. "Balut" is an incubated egg with a developed em- Materials bryo of 17 to 19 days which is boiled and eaten with or without salt. It is a Filipino delicacy that commands a Commercial boiled unfertilized and fertilized incubated good price. Using a draft-type egg incubator, the balut duck eggs (Pateros duck, Department of Agricultural In- percentage of success or percent fertility after an incuba- formation Division, 1991) obtained from the Philippines

(233) 11 J. Cookery Sci. Jpn. Vol. 40 No. 4 (2007) were wrapped in newspaper, transported to Japan and od, 99% of the fertile eggs successfully developed live stored at - 20°C until ready for analysis. Fresh duck eggs embryos. (Osaka duck strain) obtained from the Agricultural, Food Nitrogen analysis (Kjeldahl method) and Environmental Sciences Research Center of Osaka Prefecture, Osaka, Japan, were incubated in the universi- One gram wet duck egg sample in Kjeldahl tube was ty laboratory at 37°C for a specified period. Standard re- added 1 tablet of KJETAB, 4.5 g K2504+ 0.5 g CuSO4. agents were commercially obtained from Wako Chemical 5 H20 (Super Kel 142, Actac Co., Ltd. Tokyo) and 12 ml Industries, Ltd., Osaka, Japan. H2504. The mixture was slightly shaken, heated at 420°C and cooled for 15 min. The sample was then added with Balut making 70 ml deionized water, distilled and titrated in 0.1 Traditional "balut" and "penoy" making in the Philippines NH2SO4.Nitrogen was calculated as follows : The traditional way of making "balut" and "penoy" is N 1 .4007 x 0 .1 NH2SO4 x H2SO4(m/) 2(%)= Sample that thick shelled eggs no more than 5 days old from the weight(g) time they are laid are placed in cloth bags (tikbo). Duck x[]Titration value - Blank eggs are selected using the "pitik" system-tapping the (ml) eggs with the fingers to cull out eggs with cracks or Protein(%) = N2 X 6.25 thin-shelled. Eggs with cracks have a hollow sound; thin TCA extraction method of free amino acid (FAA) shelled eggs have a brittle sound. Only thick-shelled are used for "balut" making because these can withstand The FAA content in both samples was extracted using stresses of egg placement and removal in cylindrical bas- the modified method of Sanceda et al., 1998. Five mg wet kets called "toong". Eggs are incubated at 40 ± 2°C, neces- egg sample was added with 10 ml 10% TCA, hOmoge- sary to develop embryos, for 18 to 22 days, with constant nized for 5 min, centrifuged at 9,000 rpm (10,000) for changing of the position of the egg to avoid death from 10 min and filtered with filter paper No. 2. The same pro- sticking to the shells. Candling is the process of holding cess was done on the residue and the first and second su- an egg against the hole of a lighted box in a room to sep- pernatants were mixed, made up with 5% TCA to a final arate infertile eggs from fertile ones. It is first done on volume of 25 ml and the mixture was filtered with a the 11th day after incubation to separate infertile eggs membrane filter. The FAA extracts in triplicate were from fertile ones and again on the 17th day to separate measured using a high speed amino acid analyzer (Hita- eggs with dead embryos (Department of Agricultural In- chi 835 Tokyo, Japan, with ninhydrin as color reactant formation Division, 1991). Eggs with living embryos show and a single ion-exchange resin coumn (4 x 150 mm). a spider-like structure, the embryo chick is the dark spot Lithium citrate buffer was used as a standard. FAA con- in the center. Fiber-like lines around the embryo can be tents were measured at 570 and 440 nm and estimated on seen. the basis of peak areas on known concentrations of the standard using a Chromatopac Integrator D 2850 at- Japanese duck eggs incubated in the laboratory tached to the amino acid analyzer (mg 100 g). The terms unfertilized and fertilized incubated Japa- Results and Discussion nese duck eggs were used in this text to mean "penoy" and "balut", respectively, in the traditional method of pro- In the Philippines, ducks are usually fed indigenous ma- ducing the egg products. Fifty thick-shelled 5-day-old terials so that the nutrition composition of the eggs may duck eggs were placed in a carton box lined with news- vary to some extent. paper and incubated at 37°C in a lighted room. The posi- In our previous paper (Sanceda et al., 2005) , we found tion of the eggs was changed every other day. Candling that the C 14 0 to C 22 0 fatty acids of the whole egg was done on the 11thday of incubation to separate the in- decreased except for the C 20 5 fatty acid, which in- fertile eggs from the fertile ones and again from the 17th creased on the 22ndday, and the decrease was enhanced day to the end of the incubation period, to check for dead by incubation. Moreover, the n-3-C 20 5 (EPA) and the embryos. The incubated eggs were harvested 14, 18 and n-3-C 22 6 (DHA) increased significantly as incubation. 21 days after incubation and immediately boiled at 100°C progressed. This increase might be attributed to the de- for 25 min after harvesting. At the end of incubation peri- velopment of the embryo during incubation. The values

12 (234) Some fine aspects and historical background of "Balut" and "Penoy", boiled incubated fertilized and unfertilized duck eggs of n-6 PUFA both in "penoy" and "balut" decreased sig- and "balut" (151 mg/ 100 g) were higher than those of nificantly, thus contributing to the low total value of the the non-incubated ones. This suggests that the increase group, however, the values of the n-3 PUFA in both in the FAA contents was enhanced by incubation. Fur- samples increased significantly with values ranging from thermore, the total FAA was higher in "balut" than in " 0.98 to 2.32% for "penoy" and from 0.98 to 4.31% for penoy" at the same incubation periods (Table 3). "balut". This result shows the nutritional importance of Prominently, taurine increased in both "penoy" and "b this egg product. alut" samples but increased sharply in "balut" as incu- Docosahexaenoic acid (DHA) is essential for the bation progressed (Tables 2 and 3). It is possible that the growth and functional development of the brain in infants increase in taurine in "balut" might be due to the oxida- and is also required for maintenance of normal brain tion product of cysteine which decreased during incuba- function in adults. Horrocks, Yeo (1999) reported the tion. Theoretically, taurine is an oxidation product of cys- positive effects of DHA on diseases such as hypertension, teine metabolism. However, because we have not studied arthritis, atherosclerosis, depression, some cancers and the mechanism of the production of taurine in bird spe- many others. It was also reported that considering the cies, it is premature to conclude that it actually was de- role of DHA in early brain development and growth, the rived from cysteine. The increase in the amount of tau- maternal supply of DHA during growth might be of im- rine during incubation could have a positive impact on portance when fed a DHA-deficient neonatal diet the nutritive value of the samples. In mammalian tissues, (Ajuyah et al., 2003). Canada has established the Canadi- taurine is ubiquitous and is the most abundant free amino an Recommended Nutrition Intake (CRNI) at 0.5% of acid in the heart, retina, skeletal muscle, brain and espe- the energy needed that is, enriched eggs were reported cially in leukocytes (Schuller-Levis, GB, Park E, 2003). to be a source of n-3 PUFA for humans (Lewis et al., These facts adhere to our findings that taurine is abun- 2000) and are recommended for use as one source of n-3 Table 2. Free aminoacids in Penoy (mg/ 100 g) PUFA to increase individual consumption to meet the Canadian recommendations. We also found that the mois- ture content of the egg white of the non-incubated egg was significantly higher than that of the incubated eggs in both "penoy" and "balut" (Sanceda et al., 2005). Table 1 shows the crude protein in "balut" and "penoy". It was found that the crude protein in the incubated sam- ples was higher than that in the non-incubated ones. This phenomenon is reflected in our results on the amino acid analysis where incubation increased the amino acid content in the samples. Tables 2 and 3 show the FAA concentrations of penoy and balut, respectively, incubated for specified periods. The total FAA contents of the "penoy" (130 mg/ 100 g)

Table 1. CrudeProtein in IncubatedDuck Egg (%)

** = significant difference at p<0 .01 Penoy = incubated unfertilized duck egg Balut = incubated fertilized duck egg Incubated at 37°C in Cookery Science laboratory, Ochano- mizu University Duck eggs were provided by Food and Environmental Sanceda et al., 2005 Science Research Values are results of one analysis Center of Osaka Prefecture, Osaka, Japan Samples were obtained from the Philippines

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Table 3. Free amino acids in Balut (mg/ 100 g) tion known as umami. Umami is an important taste ele- ment in natural foods; it is the main taste in the Japanese stock "dashi" and in bouillon and other stocks in the west (Yamaguchi, Ninomiya, 2000). The umami taste has char- acteristic qualities that differentiate it from other tastes, including a taste-enhancing synergism between two umami compounds, L-glutamate and 5'-ribonucleotides and a prolonged aftertaste. Experimental studies have es- tablished that the presence of added MSG in foods influ- ences palatability, preference and selection (Bellisle, 1998). Sensory evaluation by both the young adults and the elderly showed that both traditional and novel foods had higher palatability ratings if MSG is added at an ap- propriate dose. Bellisle, 1998 concluded that MSG can be used casually by consumers in order to increase palatabil- ity, and it can also be used selectively by nutrition ex- perts in order to orient food selection toward a healthy diet composition. It was also reported that the preference and aversion for MSG are determined by genetic factors as well as vagus nerve function and that an aversion to high MSG concentrations is reduced by the presence of other glucogenic acids and sugars (Kondoh et al., 2000).

Japanese incubated unfertilized and

Sanceda et al., 2005 fertilized duck eggs (Osaka Duck) Values are results of one analysis To support the findings on the changes in amino acids Samples were obtained from the Philippines in the commercial duck eggs, we incubated a different dantly produced during incubation in the fertilized sam- strain of duck eggs in the laboratory under a tempera- ples especially in the presence of the completely devel- ture-controlled room. The egg products here are labeled oped embryo. Taurine and Vitamin C modify monocyte boiled incubated unfertilized and fertilized duck eggs and endothelial dysfunction in young smokers and has which are equivalent to "penoy" and "balut", respectively. been suggested that taurine supplementation has a bene- Tables 4 and 5 show the free amino acid contents of the ficial impact on macrovascular endothelial function (Fen- unfertilized and fertilized duck eggs, respectively, which nessy et al., 2003). It was also reported that pharmaceuti- increased at the end of the incubation period. It was con- cal use of the endogenous amino acid taurine, unlike firmed that the changes in amino acid contents of the many-other agents, protects electrophysiological function Japanese duck egg samples followed a similar pattern in skeletal muscle against both early and late eschaemia with that of the commercial duck egg samples. reperfusion injury (Mclaughlin et al., 2000). The supple- Emphatically, a significant increase in taurine both in mentation of taurine to a low protein diet during foetal the unfertilized and fertilized was observed. A striking and early postnatal life restores a normal proliferation difference in the taurine content between the unfertilized and apoptosis of rat pancreatic islets (Boujendar et al., and fertilized samples especially at the end of the incuba- 2002). Leucine that has the highest content in the initial tion period was observed. The taurine in the fertilized period also increased at the end of the incubation period. samples was 7-fold higher than that in the unfertilized Initially, glutamic acid was higher than any other ami- ones (Tables 4 and 5). The development of the embryo no acids except leucine and it increased in both "penoy" might play an important factor in this phenomenon. and "balut" samples and the increase was prominent as Quantitatively, the total FAA contents of eggs produced incubation progressed (Tables 2 and 3). Monosodium glu- in Japan were significantly higher (p<0.05) than those tamate (MSG) is believed to elicit a unique taste percep- obtained in the Philippines. The difference in AA con-

14 (236) Some fine aspects and historical background of "Balut" and "Penoy", boiled incubated fertilized and unfertilized duck eggs

Table 4. Free AA concentration of boiled incubated unfertilized Table 5. Free AA concentration of boiled incubated fertilized Japanese duck egg (mg/ 100 g) Japanese duck egg (mg/ 100 g)

Eggs were obtained from a Japanese poultry house and incubated Eggs were obtained from a Japanese poultry house and incubated in the laboratry at 37t Values are the means ± S.D. of triplicates in the laboratry at 37©CValues are the means ± S.D.of triplicates Values in the incubated samples with different superscript letters Values in the incubated samples with different superscript letters are significantly different from 0 day incubation (a : p<0.05, b : p are significantly different from 0 day incubation (a : p<0.05, b : p< <0.01, c : p<0.001) 0.01, c : p<0.001)

tents between the two egg samples might be attributed the Philippines. Our results confirmed that specific amino to the feed given to the ducks and to some production acids particularly taurine were higher in both the unfer- conditions. The ducks in the Philippines fed on indigenous tilized and fertilized incubated samples. The significant materials and were free to roam around the field while increase in the amount of taurine during incubation could those in Japan fed on a commercial formula feed and have a positive impact on the nutritive value of the sam- were controlled in a cage where movements are restrict- ples, therefore, the incubated eggs would be highly pre- ed. The feed composition for a laying Japanese duck con- ferred than the non-incubated ones especially in the sisted of ; 57% corn, (sorghum bicolor) ; 28% corn gluten presence of the embryo. We expect that the new infor- meal, rapeseed oil, soybean meal, corn jam ; 3% fish pow- mation in this article would bolster the use of this egg der; 1% rice bran ; 13% calcium carbonate, animal fat, product either as food or as medicine or any contribution corn steep liquour, paprika extract, NaC1, calcium phos- it could make in the field of egg research or in any egg- phate, alphalpha meal. based recipes.

Conclusions References It was clarified that Chinese traders and migrants have AICAF, Association for International Cooperation of Agricul- brought the idea of eating fertilized duck eggs to the ture and Forestry. (1988) , Useful Farming Practices, New Ed., Rice Crop, No. 23, Japan, 451 Philippines. "Balut" and "penoy" making is not native to

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Ajuyah, A. 0., Wang, Y., Sunwoo, H., Cherian, G. and Sim, J. J. eggs as a source of n-3 polyunsaturated fatty acids for hu- (2003) , Maternal diet with diverse omega-6 / omega-3 ratio mans, Poult. Sci. 7, 971-974 affects the brain : docosahexaenoic acid content of growing McLaughlin, R., Bowler, D., Kell, C. J., Kay, E. and Bouchier- chickens, Biol. Neonate 84, 45-52 Hayes, D. (2000) , Taurine protects against early and late Bellisle, F. (1998), Effects of monosodium glutamate on human skeletal muscle dysfunction secondary to eschaemia reper- food palatability. Ann. N. Y. Acad. Sci. 85, 438-441 fusion injury, Eur. I Surg. 5, 375-379 Boujendar, S., Reusens, B., Merezak, S., Ahn, M. T., Arany, E. Sanceda, N., Suzuk, E. and Kurata, T. (1998), Behavior of his- and Hill, D. (2002) , Taurine supplementation to a low pro- tamine during fermentation process in the manufacture of tein diet during foetal and early posnatal life restores prolif- fish sauce determined by an oxygen sensor, Food Flavors: eration and apoptosis of rat pancreatic islets, Diabetologia. Formation, Analysis and Packaging Influences, (eds.) Con- 6, 856-866 tis, E. T. ; Spanier, A. H. ; Shahidi, F.; Parliament, T. H. ; Davidson, A. (1999), The Oxford Companion to Food, s. v. bal- Mussinan, C. ; Ho, C. T. ; Elsevier Science B. V. 639-645 ut, Oxford University Press, ISBN 0192115790 Sanceda, N., Ibanez, J., Kurata, T., Suzuki, E. and Hatae, K. Department of Agricultural Information Division. (1991) , Que- 2005 . Changes in the Fatty Acid, Taurine and Free Amino zon City in coordination with Bureau of Animal Industry / Acid contents of incubated unfertilized and fertilized duck Livestock Development Council Brochure-10 December eggs. The Philippine Agricultural Scientist, 88, 337-349 Fennesey, F. M., Moneley, D. S., Wang, J. H., Kelly, C. J. and Schuller-Levis, G. B. and Park, E. (2003) , Taurine: new impli- Bouchier-Hayes, D. J. (2003) , Taurine and vitamin C mono- cations for an old amino acid, FEMS Microbiology Lett. 2, cyte and endothelial dysfunction in young smokers, Circula- 195-202 tion 3, 410-415 Shu, T. (2004) , Sekai no shokubunka 0, China, NouSanGyo- Horrocks, L. A., Yeo, Y. K. (2003) , Health Benefits of Doco- Son, Bunka Kyokai, T. Shu Tokyo, pp. 36-41 hexaenoic Acid (DHA) , Pharmacol. Res. 40, 211-225 Yamaguchi, S. and Ninomiya, K. (2000) , Umami and food pal- Kondoh, T., Mori, M., Ono, T. and Torii K. (2000) , Mechanisms atability, J Nutrition, 130, 921 S-926 S of umami taste preference and aversion in rats, J Nutr. 13, 966 S-9670 S Lewis, N. M., Seburg, S. and Flanagan, N. (2000) , Enriched (Received Nov, 15, 2006 Accepted Apr, 4, 2007)

あひるの受精卵と無精卵をインキュベートしたゆで卵とその歴史的背景

ノーリタサンセダ 上田久美子 ジュリアイバニェズ 鈴木恵美子 香西みどり 畑江敬子

和文抄録 インキュベートしたあひるの卵の有精卵と無精卵である"balut"と"penoy"の歴史的背景および化学成分について調 べた。試料はフィリピンで市販されているインキュベートした有精卵,無精卵のゆで卵と日本で卵を購入し,大学の研究

室で調製したものを用いた。本研究の結果,"balut"と"penoy"はフィリピンに元々あるものではなく,中国の取引業 者や移民があひるの有精卵を食べるという考えをフィリピンにもたらしたことが判明した。しかし,balut製造の知識や 技術をもっているのはbalut製造業者に限られている。今日までbalut製造は伝統的な手作りによっており,機械化され ていない。インキュベートした試料の総遊離アミノ酸量はインキュベートしていないものより高かった。タウリンは有精 卵,無精卵ともにインキュベートすることで有意に高くなった。このことはインキュベートすることで栄養的にプラスの 効果があること示している。ゆでた後,インキュベートした有精卵にはかなりの量のドリップがあり,無精卵には少量み られたがインキュベートしていないものにはほとんどなかった。

キーワード:バロット,ペノイ,インキュベートしたあひるの卵,遊離アミノ酸

宰お茶の水女子大学 纏 ウェ ス タ ン ピサ イ ア ス科 学 工 業 大 学 榊 和 洋 女 子 大 学 § 連 絡 先 お 茶 の 水 女 子 大 学 生 活 科 学 部 〒112-8610東 京 都 文 京 区 大 塚2 -1-1 TELO3(5978)5765FAXO3(5978)5760・

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