Effect of Gamma Ray Irradiation and Frying on the Thiamine Content of Bacon

Abstract

The effects of ionizing irradiation and frying on the thiamine and ribojlavin content of bacon were determined. Signijicant destruction of thiamine but not ribojavin occurred during both the irradiation and frying. The destruction of thiamine was found to be directly related to the dose of ionizing radiation or the degree of cooking. Frying before irradiation, reduction of water content by lyophilization, and irradiation at -40°C rather than 2°C produced signijicantly greater retention of thiamine. Frying the bacon following irradiation produced radiation dose-related, nonadditive, increased destruction of thiamine. The protective effect offring before irradiation was not directly linked with the reduction of moisture by h i n g .

Nutritional and other implications of irradiating meat

“…According to Fox et al (1989), the cooking-dose effect appears to involve chemical or physical changes in the tissues or vitamin which result in increased vitamin destruction or decreased extractability. Contrary to these observations, a protective effect has been identified for thiamin when bacon is cooked before irradiation (Thayer et al 1989). Despite the fact that there are small reductions in the thiamin content of meats following irradiation, it should be noted that thiamin is even more sensitive to heat than to irradiation.…”

“…Thiamin is the most radiation sensitive of the water-soluble vitamins. Measurements of the thiamin content of irradiated pork chops (Fox et al 1989), chicken (Fox et a1 1989; Hanis et al 1989; M. H. Stevenson & W. D. Graham, unpublished results), turkey (Thomas & Calloway, 1957), minced beef (Wilson, 1959), beef liver (Williams et al 1958) and bacon (Thayer et al 1989) confirm that destruction of the vitamin reflects the dose applied and the conditions used during irradiation. Thiamin levels in chicken meat decrease with increasing dose but irradiation at freezing temperatures markedly reduces the effects observed (Fox et al 1989;M.…”

“…The net effect of cooking and irradiation on thiamin retention has also been studied. Generally speaking, cooking irradiated bacon (Thayer et al 1989), pork chops and chicken breasts (Fox et al 1989) increases the rate of thiamin loss. According to Fox et al (1989), the cooking-dose effect appears to involve chemical or physical changes in the tissues or vitamin which result in increased vitamin destruction or decreased extractability.…”

Effect of Selected Fat Products on Stability of Thiamine Hydrochloride

“…Wcześniejsze badania dowodzą wpływu produktów utlenienia tłuszczów na zmiany ilościowe tiaminy, głównie w powiązaniu z działaniem wysokiej temperatury. Stwierdzono, że w procesie smażenia straty tiaminy wywołane działaniem wysokiej temperatury potęgowane są oddziaływaniem powstających produktów utlenienia tłuszczów i mogą wynosić od 10 do 50 % [18,19,22]. Biorąc pod uwagę zalecenia żywieniowe sugerujące zwiększenie w diecie człowieka poziomu kwasów tłuszczowych jednoi wielonienasyconych poprzez wprowadzenie ich m.in.…”

Nutritional aspects of irradiated food

“…Irradiation of food in the frozen state (or at reduced temperatures) and under reduced oxygen levels tends to minimize vitamin losses [14]. Whether food is irradiated before or after cooking also seems to affect the thiamine losses [34], while new packaging techniques, for example modified atmosphere packaging, also seem to have favourable effects on meat quality when combined with irradiation [35]. Pretreatments, such as marinading prior to irradiation, seem to enhance the ability of irradiation to reduce bacterial growth, and also help to preserve sensory quality [36].…”