INCORPORATION OF MINCED TROUT (ONCORHYNCHUS MYKISS) INTO EGG-BASED NOODLES

Recovering minced fish from fish frames following filleting operations is a common way to increase fish muscle yield as well as fully utilize aquatic food resources. Therefore, it is important to develop new and feasible applications for minced fish that will add value to fishery products. In this study, washed minced trout (Oncorhynchus mykiss) was incorporated at 10 and 20% flour replacement level into a conventional egg noodle formulation. Textural attributes (by TPA) of cooked noodles were evaluated. In addition, textural, functional and sensory attributes of fried noodles, a snack food item, were also evaluated. Visual color (CIE )‐Lab of fresh noodles containing minced trout was less red and yellow than the control and the overall difference in color (ΔE) increased as the level of minced trout increased. Noodles incorporating 10% minced trout had cooked texture profiles similar to the control; however, there were significant decreases in hardness, gumminess and chewiness in the cooked noodles containing 20% minced trout. For the fried noodles, adding fish tended to reduce the yellow color and yielded a product with texture profiles similar to the control at a 10% substitution level. The experimental and control products were acceptable. Product preference was evenly divided between the control fried noodle and the noodle containing 10% minced trout.     

INTEGRATED STUDIES ON THE FRESHNESS OF RAINBOW TROUT (ONCORHYNCHUS MYKISS WALBAUM) POSTMORTEM DURING CHILLED AND FROZEN STORAGE

Rainbow trout were killed by two methods, asphyxiation and clubbing. The concentration of ATP in specimens of skeletal muscle taken immediately after death was significantly (P<0.01) higher in clubbed (4.41 ± 0.86 μmol/g) than in asphyxiated (2.00 ± 0.69 μmol/g) fish. The shear force (Warner-Bratzler) required to cut the muscle was higher (P<0.05) in clubbed (8.33 ± 0.61 N) than in asphyxiated (6.85 ± 0.98 N) fish. Changes in the concentration of adenine nucleotides and in shear force were measured at intervals during storage at 3C and - 30C. The K value was calculated and was found to be correlated inversely with changes in shear force, Torrymeter readings and sensory assessment. There were no significant differences in the concentrations of ATP and metabolites between muscle sites. There were no differences in shear force measurements between the locations sampled nor between muscle taken from the right and left sides of the fish.     

DETERMINATION OF GLASS TRANSITION TEMPERATURE OF RAINBOW TROUT (ONCORHYNCHUS MYKISS) AND EFFECTS OF VARIOUS CRYOPROTECTIVE BIOPOLYMER BLENDS ON SOME CHEMICAL CHANGES

Sucrose  +  sorbitol  +  gum arabic (2  +  2  +  0.15%), sucrose  +  sorbitol  +  carrageenan (2%  +  2%  +  0.15%), sucrose  +  mannitol  +  gum arabic (2%  +  2%  +  0.15%), sucrose  +  mannitol  +  carrageenan (2%  +  2%  +  0.15%), sorbitol  +  mannitol  +  gum arabic (2%  +  2%  +  0.15%) and sorbitol  +  mannitol  +  carrageenan (2%  +  2%  +  0.15%) were blended with ground rainbow trout and stored at glass transition temperature ( T _g) of rainbow trout ( − 13C), determined by differential scanning calorimetry at − 9 and − 18C for 6 months. Total volatile basic nitrogen (TVB-N) and thiobarbituric acid-reactive substances (TBARS) were determined at 1st, 3rd and 6th months of storage periods. Biopolymer blends and storage period had a significant effect ( P <  0.05) on the TVB-N and TBARS values. T _g and − 18C showed same effect on TVB-N and TBARS values but − 9C has statistically different effect on them.

PRACTICAL APPLICATIONS

The T_g value was found as −13C for rainbow trout. This value is higher than commercial storage temperature (−18C). This has a great importance in terms of economical viewpoint. It was determined that TVB-N values were same and TBARS values were similar at the end of 6 months storage at T_g and −18C. When considering these two parameters, it can be accepted that −13C could be an indicator of usability instead of −18C.     

EFFECT OF TRISODIUM PHOSPHATE ON LISTERIA MONOCYTOGENES ATTACHED TO RAINBOW TROUT (ONCORHYNCHUS MYKISS) AND SHRIMP (PENAEUS SPP.) DURING REFRIGERATED STORAGE

The potential of using trisodium phosphate (TSP) to reduce bacterial populations in fresh fishery products was explored since TSP has recently been approved by USDA for its usage in poultry processing to eliminate Salmonella contamination. Fresh headed shrimp and rainbow trout fillets were inoculated with L. monocytogenes before dipped in tap water, 10% TSP, or 20% TSP solutions and overwrap-packaged. Surface pH values, psychrotrophic plate counts, and L. monocytogenes counts of inoculated shrimp and trout fillets were determined after 0, 3, 6, and 9 days of storage at 4C. The TSP treatment resulted in relatively high residual surface pH values (11–12) initially in both shrimp and trout fillets. Compared to tap water dipping, TSP treatment did not significantly reduce psychrotrophic or Listeria populations in shrimp. However, the 20% TSP treatment significantly (p < 0.05) lowered 0-day psychrotrophic and L. monocytogenes counts of trout fillets and remained effective for 6 days during storage at 4C .     

QUANTITATIVE EXTRACTION OF NUCLEOTIDES FROM FROZEN MUSCLE SAMPLES OF ATLANTIC SALMON (SALMO SALAR) AND RAINBOW TROUT (ONCORHYNCHUS MYKISS): EFFECTS OF TIME TAKEN TO SAMPLE AND EXTRACTION METHOD

Muscle excised from the dorsal flank of Atlantic salmon and rainbow trout at death and up to 120 min postmortem (P.M.) was frozen in liquid M₂ and stored at ‐80C. Following acid extraction, on ice (method 1), or dry ice (method 2) samples were analyzed for cyclic nucleotides to determine the effect of time to sample, and extraction method. There was no pattern of change in nucleotide profile in either species up to 10 min P.M. At 120 min P.M., Atlantic salmon muscle extracted by method 2 had a higher IMP concentration than at any other time but there was no difference in adenylates. Ignoring time taken to sample, method 2 resulted in higher adenylate and lower IMP concentration than method 1. These results indicate that method 2 is most effective in obtaining realistic nucleotide concentrations from fish muscle because it maintains the tissue temperature below the critical freeze zone, (‐0.8 to ‐5C) prior to enzyme inactivation.     

EFFECT OF DIETARY VITAMIN E AND SURFACE APPLICATION OF OLEORESIN ROSEMARY ON IRON/ASCORBATE-STIMULATED LIPID OXIDATION IN MUSCLE TISSUE AND MICROSOMES FROM RAINBOW TROUT (Oncorhynchus mykiss)

The effect of dietary α-tocopheryl acetate and surface application of oleoresin rosemary on iron/ascorbate-induced lipid oxidation in rainbow trout ( Oncorhynchus mykiss ) muscle and microsomes was investigated. The 2-thiobarbituric acid-reactive substances (TBARS) values of muscle and microsomes isolated from fish fed the higher concentration of α-tocopherol (500 mg/kg feed) were smaller than those of fish fed the lower concentration (100 mg/kg feed). The protective effect of oleoresin rosemary on lipid oxidation in fish muscle was also observed. Analysis of variance revealed a significant (p < 0.01) interaction between dietary treatments and incubation time. Dietary α-tocopherol supplementation significantly increased the α-tocopherol concentration of muscle microsomal membranes, thereby increasing the oxidative stability of the membrane lipids.     

THE EFFECTS OF DIETARY α-TOCOPHEROL AND SURFACE APPLICATION OF OLEORESIN ROSEMARY ON LIPID OXIDATION AND CHOLESTEROL OXIDE FORMATION IN COOKED RAINBOW TROUT (Oncorhynchus mykiss) MUSCLE

The inhibitory effect of dietary α-tocopherol supplementation (100 and 500 mg α-tocopheryl acetate/kg diet) and an oleoresin rosemary dip on lipid and cholesterol oxidation in cooked rainbow trout ( Oncorhynchus mykiss ) during storage at 4C for 48 h was investigated. The 2-thiobarbituric acid-reactive substances (TBARS) values of cooked fish muscle increased during storage for all treatments. Dietary α-tocopherol supplementation partially inhibited lipid oxidation. Surface application of oleoresin rosemary further enhanced this protective effect. Cholesterol oxides were formed in all the samples following cooking and storage. The major cholesterol oxidation products (COPS) were identified as 7 β-hydroxycholesterol, α- and β-epoxides, and 7-ketocholesterol. Formation of COPS was reduced by dietary supplementation with α-tocopherol and surface application of oleoresin rosemary. Statistical analysis revealed a highly significant (p < 0.01) inhibitory effect of oleoresin rosemary on COPS formation.     

QUALITY OF FISH SAUCE PRODUCTS FROM RECYCLED BY‐PRODUCTS FROM FISH GEL AND KAMABOKO PROCESSING

ABSTRACT

In order to make effective reuse of kamaboko processing wastes and to minimize the amount of waste disposal, the production of two kinds of fish sauces was tried on a small industrial scale from the wastes with or without the addition of the meat of deepsea smelt (Glossanodon semifasciatus). They were fermented for 6 months at room temperature using salt and koji mold. As a control, a fish sauce was also produced only from the deepsea smelt meat. The recovery of fish sauce from the initial mashed mixture ranged between 75 and 79%, depending on the ingredients in the three fish sauce products. The total nitrogen content of the waste sauce and the mixed sauce was lower than that of the control. The levels of the original additives to kamaboko products, β‐carotene and sorbic acid, were very low in these fish sauces. The taste‐active components of the waste sauce and mixed sauces were lower than those of the control. Sensory evaluation revealed that the former two waste sauces were less bitter and higher in saltiness than the control. However, no difference was found in umami taste between these products. These findings suggest that the wastes from kamaboko processing factories could be reused as fish sauce for food condiments.

PRACTICAL APPLICATIONS

Recent development in the food industry in Japan has enabled the surimi‐based products to be mass produced and standardized even in the fish gel, kamaboko trade. However, a serious problem has arisen in the development of kamaboko processing through the discharge of the wastes, i.e., nonstandard products or fragments, from kamaboko processing factories. It is clear that the waste from kamaboko processing factories is transformed effectively into fish sauce by using soy sauce koji mold. As a result, the amount of the discharged wastes from kamaboko factories are able to be minimized because the liquefaction ratio of the fish sauce mushes (moromi) from the wastes after fermentation was high and the products have a high umami taste and agreeable soy sauce‐like flavor.     

THE QUALITY OF VEGETABLE OIL FROM THREE VARIETIES OF SUNFLOWER SEEDS (HELIANTHUS ANNUUS)

ABSTRACT

Vegetable oils become susceptible to oxidation during their processing. The appropriate extraction and refining conditions of oil from two experimental cultivars (Madero‐91 and Cianoc‐2) of sunflower seeds and a commercial one (Victoria) as a control, were studied. Isopropyl alcohol was used in the extraction and refining, and compared with hexane. The refining was performed by the miscella method at 40, 50, 60 and 70%. Free fatty acids (FFA) and malonaldehyde analysis of crude oils afforded no significant differences among solvents and sunflower varieties. In refined oils, differences found with the miscella concentration, the malonaldehyde content and FFA content were not significant. Cianoc‐2 was the best source for oil production because of its lower values in FFA and malonaldehyde content.

PRACTICAL APPLICATIONS

The use of hexano in refining vegetable oil in Mexico is common, lack of knowledge about the use of new solvents and their impact on the processing conditions with sunflower seed cultivars is lack. The present work describes at lab scale, the work conditions, advantages and posibilities and limitations of the use on isopropyl alcohol in comparison with hexane and the use of three Mexican cultivar with this approach, with emphasize in oxidation conditions of refined vegetable oil.