Reaction Rates for Decomposition of Thiamin in Pork at Various Cooking Temperatures

Low-dose gamma irradiation of vacuum-packaged, ground fresh pork resulted in a dose-dependent, first-order rate of thiamin destruction (R*=0.99). Thiamin losses for raw pork irradiated at 0.57, 1.91, 3.76, 5.52 and 7.25 kGy were 7.7, 23.5, 38.1, 49.8 and 57.6%, respectively, of the nonirradiated sample. Post-irradiation cooking resulked in additional thiamin losses of i1.3, 11.5, 13.0, 13.6, 13.Fand 15.0% for respective treatment samples irradiated at doses of 0, 0.57, 1.91, 3.76, 5.52 and 7.25 kGy. Time of storage had little effect on the thiamin content of raw irradiated and nonirradiated pork.

Section: Cooking Treatmentsupporting

confidence: 83%

Effect of Low‐Dose Irradiation and Post‐Irradiation Cooking and Storage on the Thiamin Content of Fresh Pork

Jenkins

Thayer

Hansen

1989

“…Thiamine was low in all products that did not contain pork. For the pork products, the thiamine content was variable, which undoubtedly reflected the severity of the processing methods, the amount of pork used in the products, the variation in thiamine content of different muscles and the thiamine nutrition of the animals before slaughter (2, 3, 4, 5, 6, 7, 8, f0, 11,12,13,14). The values for the pork products studied varied from 0.15 to 0.50 mg. per 100 g., while values from 0.6 to 1. comparable since the original thiamine values before processing were not known, the data would suggest that considerable destruction of thiamine occurred during the processing of the canned pork samples, and the retention of thiamine was somewhat less than during the cooking of fresh pork by standard procedures (8).…”

Section: Resultsmentioning

confidence: 99%

THIAMINE, RIBOFLAVIN, AND NIACIN CONTENT OF PROCESSED MEATS^a

Schweigert

Bennett

Marquette

et al. 1952

Extensive studies have been conducted on the vitamin content of uiicooked and cooked fresh meats; however, the data available on the vitamin content of various processed meats are limited. The ready-to-eat ineats classified as sausages, for example, constitute approximately 10% of the total meat production of government-inspected plants (2). The purpose of the present studies was to determine the proximate composition and thiamine, riboflavin, and niacin content of certain processed meats obtained during 1949 and also in 1950. The samples selected for this study included sausage items, canned meat products, and cured meats. EXPERIMENTAL METHODSThe meat samples were purchased from a retail store that had a high turnover and large meat trade. Two or more pounds of each type of meat were obtained and the sausage and luncheon meat samples were taken from uncut pieces of meat that had not been in the showcase. For the canned meats packed in less than 1-pound cans the entire contents of 4 or 5 cans were used and pooled. All samples were ground and thoroughly mixed to assure homogeneity. They were then stored at 23"F.(5"C.) prior to analysis. These samples were ion, thiamine, riboflavin, and niacin. Thiamine was oflavin both fluorometrically and microbiologically, an ly with the use of methods similar t o those described by the Association of Vitamin Chemists (1).The proximate analyses and vitamin content of the samples obtained in 1949 are summarized in Table 1 and f o r 1950 in Table 2. RESULTS AND DISCUSSIONThe results show that all of the meat products except head cheese, potted meat, and bacon were excellent sources of niacin. Bacon and head cheese were low in riboflavin. When the vitamin content of the samples are compared on a n equal protein basis bacon compares favorably with the other samples in vitamin content.Thiamine was low in all products that did not contain pork. For the pork products, the thiamine content was variable, which undoubtedly reflected the severity of the processing methods, the amount of pork used in the products, the variation in thiamine content of different muscles and the thiamine nutrition of the animals before slaughter (2, 3, 4, 5, 6, 7, 8, f0, 11, 12, 13, 14). The values for the pork products studied varied from 0.15 to 0.50 mg. per 100 g., while values from 0.6 to 1.5 have been observed for uncooked pork loin and ham samples. Although the values are not strictly

“…The effect of p H on the rate of thiamine destruction in pure solutions has been explored (8,16), with the result that it is well known that thiamine is less stable in alkaline than in acid solutions. Although the stability of thiamine in the presence of extraneous materials, such as foodstuffs, and the more common anions also has been investigated (6,17), conclusions from this work often have been masked by factors which are only vaguely understood.…”

mentioning

confidence: 96%

“…

…”

mentioning

confidence: 99%

FACTORS INFLUENCING THE STABILITY OF THIAMINE DURING HEAT STERILIZATION^a

Bendix

Heberlein

Ptak

et al. 1951

The effect of heat and certain environmental factors on thiamine stability has been the subject of several comprehensive investigations (2, 3, 8,9,10,12,13, 14,16,17, 18,19). There is good evidence that in pure thiamine solutions the destruction by heat is primarily a hydrolytic cleavage to give pyrimidine and thiazole derivatives (20), and that the reaction rate may be expressed by the conventional equation for a first-order reaction. The effect of p H on the rate of thiamine destruction in pure solutions has been explored (8, 16), with the result that it is well known that thiamine is less stable in alkaline than in acid solutions. Although the stability of thiamine in the presence of extraneous materials, such as foodstuffs, and the more common anions also has been investigated (6, 17), conclusions from this work often have been masked by factors which are only vaguely understood.An expanded knowledge of the factors which influence the stability of thiamine during the sterilization of canned foods is needed by those individuals engaged in developing new food processing methods which might improve the retention of this important vitamin. This is especially true if such information could lead to generalizations in regard to destruction rates at elevated temperatures. Recent descriptions (5, 11, 15) of new processing methods make reference to the markedly improved thiamine retentions which may be realized commercially through the use of high-temperature, short-time processing methods. Some workers ( 5 ) have pointed out that the amount of thiamine destruction during sterilization has been often used as an index to other chemical changes which take place during processing. EXPERIMENTALFour vegetables which are normally processed in large quantities were selected for systematic investigation with regard t o the effect of time, temperature, and other variables which might affect thiamine stability. F o r this purpose, tomato juice was chosen as a typically acid product which requires a relatively mild heat treatment in order to render it sterile. Peas and corn were selected as products which require a relatively intense heat treatment for sterilization, and which represent a high and a low thiamine product, respectively. Lima beans were included because significantly different degrees of retention of thiamine had been previously noted upon processing mature and immature Lima beans in the same retort (71 and 5070, respectively) (4).As a general approach, it was decided that each of these products should be processed over a rather wide temperature range, and that the thiamine content should be determined a t relatively short intervals of time during the course of processing. In order to assure a uniform temperature over substantially all of the time interval of the experiment, all processing was done in small containers (211 x 214 or 208 x OOS), and *Presented a t the Eleventh Annual Meeting of the IFT, New York, N. Y.