Stability of Whole, Filleted, and Minced Trout (Salmo Irideus Gibb) During Frozen Storage

Abstract

I n order to determine the behavior of trout (Salmo irideus Gibb) muscle in frozen storage, five lots (whole, fillets, and minces obtained by extrusion, "rnincer" and "cutter'y were made and stored at -2OOC for one year.During this period the mince, mainly the one made with "cutter", was more denaturated than the whole trout and fillets. The highest rate o f insolubilization was reached by 255 days of storage (45% of soluble protein in minces and 6 W 0 in fillets and whole fish). Also a similar difference was noticed in the cooking drip.The variations o f protein solubility do not thoroughly explain the changes in objective texture observed up to 30-75 days of storage. So, other parameters may be connected with these changes.On the other hand, after 165 days, the rancidity increase measured by the TBA value is high, especially in the mince although rancid flavor was detected at 120 days of storage.

STABILITY OF FROZEN TROUT I. TREATED AND UNTREATED MINCES STORED AT -12, -18, and -24 °C

“…In all cases three replicates were made. The yield obtained with the method employed was 28% higher than that reported in an earlier study (Borderias et al 1982), in which the minces were obtained from fillets extruded through a conventional press. The results of the routine analyses are shown in Table 1.…”

“…Proximate analyses (crude protein, crude fat, moisture content, and ash content) (AOAC 1975) and analyses of trout mince yield were effected, along with initial and routine quality controls to measure changes in the amount of protein soluble in 5% NaCl (Ironside and Love 1958), the K value (Saito et al 1959), cooking loss (Borderias et al 1982), the TBA index (Lemon 1975), and pH. Taste (overall and rancidity) and texture (hardness and juiciness) were evaluated by means of a six-member sensory taste panel chosen from among the laboratory staff; hardness was rated using the preferenceacceptance method and a 5-point, bipolar scale in which 5 = normal; 4 = some what soft (s), somewhat hard (h); 3 = soft, hard; 2 = very soft, very hard; and 1 = mushy, extremely hard.…”

“…In a n earlier paper, the authors reported on a study of the suitability of frozen storage when applied to trout minces (Borderias et al 1982). This paper presents a discussion of a study on the effect of different temperatures and the use of protein cryoprotectants and antioxidants on the quality of extruded trout muscle, which appears to be the most adequate for commercial purposes.…”

Biochemical and Morphological Changes in Grass Shrimp (Penaeus Monodon) Muscle Following Freezing by Air Blast and Liquid Nitrogen Methods

“…Protein solubility of carp (Suzuki ef al. 1964) and rainbow trout (Borderias et al 1982) frozen immediately after slaughter also increased during storage at -2OC. Instantly killed carp stored at 25C also showed a slight increase in salt soluble protein in 2 days (Seki and Watanabe 1982).…”

“…However, the effects of using liquid nitrogen and air blast-freezing on the morphological and functional properties of these products have not been objectively compared. Most studies of frozen fish have emphasized the changes during frozen storage (Bello et al 1981;Borderias et al 1982;Kelleher et al 1982;Owusu-Ansah and Hultin 1984, 1986, 1987Jimenez-Colmenero et al 1988). This is probably due to the fact that ice recrystallization occurs during storage and overshadows the effects of initial crystallization during freezing.…”