95 Nippon Shokuhin Kogyo Gakkaishi Vol. 26, No.2 (1979) (44)

Studies of the Stability of 5'-Ribonucleotides in †

KIYOFUMI ISHII*, SEISHI TAKAGI* and YUKIHIRO NAKAO*

The influencesof processingcondition in meat products,particularly sausage, on the stability of added 5'-ribonucleotideswere studied. The resultsare as follows. (1) In case of sausage without , the internaltemperature of sausage was raised so rapidly in short time that added 5'-ribonucleotideswere very stable. (2) On the contrary,in case of sausage with smoking, though the stabilityof added 5'-ribonucleotidesdepended on the smoking condition,they were fairlydecomposed even in the case of small casing such as wiener and they were moreover de- composed in the case of largercasing such as frankfurterand bologna. (3) There methods, that is, (a) coating 5'-ribonucleotideswith hydrogenated vegetableoil, (b) adding polyphosphate to sausage, and (c)adding glucono-delta-lactoneand smoking at high temperature for short time, were studiedto keep added 5'-ribonucleotidesstable in smoking process. All these methods were found to be effective.

In the previous report1),the stabilityof coating with 3 times weight of hydrogenated added 5'-ribonucleotidesin dried soup mixes vegetable oil (mp 58-60℃). and in raw materials therein was studied. 2. Determination of 5'-ribonucleotides

In meats products, added 5'-ribonucleotides 5'-Ribonucleotides in the sausage were may be decomposed during processing by determined by using the enzyme method of phosphatase present in meats2). Though the NAKAJIMA et al.6) One μmole of added 5'- stabilityof 5'-ribonucleotidesadded during ribonucleotides corresponds to 535 μg of them. the processing of fish sausage3),kamaboko 3. Preparation of sausage and meat sausage products4,5)has previously 3.1 In case of sausage without smoking been reported,the study on the stabilityof Process 5'-ribonucleotidesadded to meat products in The formulation used was lean mutton view of their processing conditions has 29%, lean 7%, horse meat 22%, tuna scarcely been published. meat 7%, back fat 7%, corn starch 4.3%, This study concerns the influenceof the ice 21.7%, salt 1.6%, sodium nitrite, season- processing condition of meat products, ing and polyphosphate. The lean meats and especiallysausage, on the stabilityof added back fat were ground through a 2mm plate. 5'-ribonucleotides. The ingredients were comminuted in a chopper for 3min. 5'-Ribonucleotides were dissolved Experimental with water and mixed thoroughly into the 1. Materials sausage emulsion. After the emulsion was Commercial pork, , mutton and horse stuffed into vinylidene chloride casings (3.6 meat were used for the preparationof sausage. cm and 8.0cm in diameter), the cooking 5'-Ribonucleotidesconsisting of equal amounts process was carried out for 1hr at 80℃. of disodium 5'-inosinateand disodium 5'- 3.2 In case of sausage with smoking guanylate and coated 5'-ribonucleotideswere process obtained from Takeda Chemical Ind., Ltd. (1) Wiener: The formulation was lean Coated 5'-ribonucleotideswere prepared by beef 26%, beef heart 3.2%, lean pork 16.2%,

† Application of 5'-Ribonucleotides to Foods, Part 2 * Food Research Laboratories, Food Products Division, Takeda Chemical Industries, Ltd. Juso-

Honmachi, Yodogawa-ku, Osaka (45) ISHII, TAKAGI & NAKAO: Application of 5'-Ribonucleotides to Foods, Part 2 96

Table 1. Stability of Added 5'-Ribonucleotides in Sausage before and after Cooking without Smokinga)

back fat 19.5%, skim milk 7.1%, salt 2.0%, manner as wiener. After the emulsion was sodium nitrite and seasoning. The lean meats stuffed into cellulose casings (diam., 5.16cm and back fat were ground through a 2mm and 8.75cm), the cooking was carried out plate. The ingredients were comminuted in at 60℃ and smoking was begun at 66℃ and a chopper for 3min. 5'-Ribonucleotides or the temperature was raised to 78-82℃. coated 5'-ribonucleotides were mixed in the After the bologna had reached an internal emulsion for 3min. After the emulsion was temperature of 68℃, the smoking was stuffed into cellulose casing (diam., 1.6cm), finished. the cooking was begun at 54.5℃ in smoke- Results and Discussion house and the smoking was conducted at

65.5℃, gradually heated up and finished at 1. Stability of added 5'-ribonucleotides in 77℃. sausage without smoking

(2) Frankfurter: The formulation was The stability of added 5'-ribonucleotides lean beef 41%, lean pork 17%, beef fat 17%, in it before and after cooking is shown in ice 22%, salt 2.6%, sodium nitrite and season- Table 1. Fig. 1 shows the internal temperature ing. It was prepared in the same manner of sausage cooked in hot water at 80℃. It as wiener. The emullsion stuffed into cellulose was found that added 5'-ribonucleotides in casing (diam., 2.6cm) was cooked at 60℃, cooked sausage were very stable and from then heated up to 71℃, followed by smoking 74 to 94% of them was kept remaining. at the same temperature and the smoking Internal temperature of this cooked sausage was finished at 80℃. After smoking, the with 3.6cm casing reached above 70℃ in cooking was carried out at 80℃ for 15min. from 10 to 15min as shown Fig. 1. The

(3) Bologna: The formulation was lean phosphatase in pork was previously reported beef 40%, lean pork 33.1%, ice 21.8%, salt to be inactivated by heating at 70℃ for 2.33%, sodium nitrite and seasoning. The 5min2). It appears, therefore, that in case preparation was performed in the same of this small casing, the temperature at 97 日本食 品 工業 学 会誌 第26巻 第2号 1979年2月 (46) which the phosphatase in meats was highly ribonlucleotides in wiener and frankfurter, active, was passed through so rapidly that respectively. The remaining added 5'- added 5'-ribonucleotideswere kept very ribonucleotides therein were from 48 to 66%. stable.On the contrary, in case of larger They were decomposed even in case of small casing such as of 8.0cm in diameter, about casing such as that used for wiener. It took 60% of added 5'-ribonucleotidesremained. long time from 40 to 50min to raise the As shown in Fig. 1, added 5'-ribonucleotides internal temperature to 40℃ and from 90 to were decomposed because they had been 120min to 62℃. It was previously reported attacked by phosphatase in meats for a long that while the phosphatase activity in meats time at its optimum temperature. was high below 40℃, it was gradually 2. Stabilityof 5'-ribonucleotidesin sausage inactivated above 40℃ and was almost lost with smoking at 70℃7). The smoking schedule and internal tem- When the relationship is considered between perature of wiener, frankfurterand bologna the change of internal temperature and the are shown in Figs, 2, 3 and 4, respectively. phosphatase activity in wiener or frankfurter Tables 2 and 3 show the stabilityof added in smoking process, the remarkable decom- 5'-ribonucleotides(regular) and coated 5'- position of added 5'-ribonucleotides in these

Fig. 1. Internal temperature of sausage cooked in hot water Fig. 3. Smoking schedule of frankfurter sausagea)

Fig. 4. Smoking schedule of bologna sausage

Fig. 2. Smoking schedule of wiener sausagea) (47) ISHII, TAKAGI & NAKAO: Application of 5'-Ribonucleotides to Foods, Part 2 98

Table 2. Stability of Added 5'-Ribonucleotides and Coated 5'-Ribonucleotides in smoked Wiener

Table 3. Stability of Added 5'-Ribonucleotides and Coated 5'-Ribonucleotides in Smoked Frankfurter

Table 4. Stability of Added 5'-Ribonucleotides and Coated 5'-Ribonucleotides in Smoked Bologna

products can be explained to be due to the Table 4. fact that they were passed through for a In terms of keeping added 5'-ribonucleotides long time the temperatures at which the stable in sausage with smoking, three methods phosphatase in meats was highly active. may be considered. This fact is more evident in the case of First: 5'-Ribonucleotides should be coated bologna sausage stuffed into larger casing. with something such as edible fat to avoid The remaining added 5'-ribonucleotidewere bringing them into contact with phosphatase. about 16% and below 11%, as shown in Second: Polyposphate should be added to 99 日本食 品工 業 学 会 誌 第26巻 第2号 1979年2月 (48)

Table 5. Effect of Pyrophosphate on the Stability of Added 5'-Ribonucleotides in Smoked Wiener

Table 6. Effect of Added Glucono-Delta-Lactone on the Stability of Added 5'-Ribonucleotides in Smoked Wiener

meat products as a competitor to prevent tion of them may be due to the fact that 5'-ribonucleotides from being decomposed by the coating film was broken during the the attack of the phosphatase in meats, as chopping process. In bologna, however, the TOMIYAMA et al.3) showed in fish sausage remaining 5'-ribonucleotidescoated with this

products. agent decreased in comparison with those Third: Smoking processing should be done in wiener as shown in Tacle 4. In another as short as possible. experiment, 5'-ribonucleotideswhich were

(1) The effect of coating agent coated with hydrogenated vegetableoil with In order to keep 5'-ribonucleotides stable, higher melting point, remained from 69 to the following specification as coating agents 75%. should be required. Coating agents do not (2) The effectof polyphosphate melt at the temperature at which the Adding polyphosphate to smoked meat was phosphatase is highly activated, but melt at effective to stabilize5'-ribonucleotides as the temperature at which the phosphatase shown in Table 5. Polyphosphate is useful is inactivated. From the results of many for prevention of 5'-ribonucleotidesfrom investigations, it was found that hydrogenated decomposition under the condition of being vegetable oil melting at 58-60℃ was suit- attacked by phosphatase in meats for a long able for the coating agent. The stabilities time in smoking Process. of 5'-ribonucleotides coated with this coating (3) The effectof cure accelerator agent are shown in Tables 2, 3 and 4. The There is a report that by using glucono- coating with this agent was effective measure delta-lactone(GDL) as cure accelerator,the against the decomposition of 5'-ribonucleo- meat products are kept at a high temperature tides. From 17 to 30% of the decomposi- from the beginning and the cooking time can (49) ISHII, TAKAGI & NAKAO: Application of 5'-Ribonucleotides to Foods, Part 2 100

to the fact that the internal temperature passed rapidly through the temperature range of the highest activity of phosphatase in meats. From these results, the attention should be paid to the processing condition in applica- tion of 5'-ribonucleotides to meat products.

Literatures

1) ISHII,K., TAKAGI, S. and SATANI,F.: Nippon Fig. 5. Internal temperature of wiener sausage Shokuhin Kogyo Gakkaishi (J. Jpn.Soc. Food containing glucuno-delta-lactone Sci. Technol.)26, 89 (1979). 2) TODA, J.,NAKATANI, H., ISHII,K. and FUJITA, E.: J. Jpn.Soc. Food Nutr., 18, 60 (1965) (In Japanese). 3) TOMIYAMA, T., KITAYAMA, K. and ABE, T.: be much shortened7). On the basis of this Report in the meeting of Jpn. Soc. Sci.Fish. method, the wiener was prepared by addition (Spring,1963). of 0.3% GDL, and cooking and smoking at 4) OBARA, M. and KOYAMA, Y.: Jpn. Food Sci., 121℃. 3, 14 (1963). The stability of 5'-ribonucleotides or coated 5) FUJII,Y.: Report of Symposium in the meet- 5'-ribonucleotides, and the internal tempera- ing of Jpn. Soc. Sci. Fish. p.12 (Autumn, ture in its preparation are shown in Table 6 1968). and Fig. 5, respectively. 5'-Ribonucleotides 6) NAKAJIMA, N. and MORI, H.: J. Takeda Res. added to these wiener samples were very Lab., 37, (1-2),113 (1978). stable regardless of whether regular or coated 7) Anonymous: Food Eng., 36, (19),152 (1964). 5'-ribonucleotides were used. This is due (ReceivedJun. 30, 1978)