Qualitat under Verwertung von Fruhjahrshering aus der Ostsee

The utilization of spring herring caught off the eastern German Baltic Sea coast in the waters around Rügen Island has a long tradition. Since 1991 there was a dramatic decrease in herring fisheries in this area. To promote the better use of this typical spring herring stock an exploratory fishery was started from January to May 1999 accompanied by quality investigations. The results show the possibilities of utilization according to length distribution, fat content and quality aspects.

Fettgehalte von Makrelen in Abhängigkeit von der Größe, dem Fanggebiet und der Jahreszeit

Data on the fat content in the edible part of mackerel in correlation to the length are given for nine different fishing grounds. The samples were taken in spring and summer in the North Sea, west and south of the British Isles and in the bay of Biscay.

The evolution of body muscle composition of the African catfish (Clarias gariepinus) (Burchell 1822)

Changes in body muscle composition of Clarias gariepinus were studied in fish reared from 1.08 g to 383 g mean body weight in a 201-day culture period. Changes in the amount of protein content, dry matter and ash free dry matter in the muscle tissue can be described as a function of body weight. The percentage of protein content was observed to be higher in bigger fish. Fat content was low throughout the fingerling stage. Specific growth rate decreased significantly at 400 g mean body weight (P<0.05) while feed conversion rate increased. The conclusion, based on the culture conditions in this study, is that the optimal weight for harvesting C. gariepinus is 400 g.

Biochemical composition of the muscle of some freshwater fishes during the pre-maturity phase

Biochemical composition of the muscle of juveniles belonging to 18 different species of freshwater fishes showed that the protein percentage in juveniles was higher than the adults. The fat, on the other hand, was much lower. This suggests that the body fat increases with the onset of maturity. No clear inverse relationship was found between fat and protein in juveniles. Moisture percentage was very high in juveniles. This was probably because of low fat content. In most species the sum of fat and water contents (F + W) was found to be constant. The percentages of ash, calcium and phosphorus were higher in juveniles than those of adults. Dry matter percentage varied inversely with the moisture and in most species carbohydrate was generally low. In juveniles although the calorific value of protein-fraction was high the total calorific value was lower than the adults.

An effective method for reducing belly-bursting in frozen oil sardines

A dip treatment in 15% sodium chloride solution for 30 minutes prior to freezing was found to be effective in reducing belly-bursting occurring during freezing and thawing of oil sardines. The effect of size and fat content of sardines on belly-bursting phenomenon and storage characteristics of brine treated sardines have been studied.

Development of canned products from Indian major carp, catla (Catla catla)

Pieces of catla fish (Catla catla, a major carp of lndian subcontinent) of length 10 to 11 cm and thickness 1.0 to 1.5cm were precooked by two methods; steam precooking and frying. The precooked pieces were packed_in No.1 tall can (30lx411) with various hot filling media like oil, brine, tomato sauce and curry. Cans were seamed by a hand seamer and retorted at 117.2° C (12 psi) for 90 minutes. All the canned products had satisfactory cut-out, biochemical and organoleptic characteristics. Steam precooked canned products had moisture content of 65.6 to 74%, protein content of 20.8 to 22%, fat content of 1.1 to 6.6% and ash content of 2.1 to 2.5%; whereas fried canned products had moisture content of 65.4 to 68.2%, protein content of 21.3 to 22%, fat content of 7 to 10.2% and ash content of 2.1 to 2.7% on wet wt. basis. Salt content in steam precooked and fried canned products varied from 1.2 to 1.9% and 2.0 to 2.5% respectively. All the canned products were organoleptically good. However, degree of preference varied for different products. Canned fried catla in curry was the best product among all types of packs. Among the precooking methods, frying was more efficient than steam precooking in controlling the amount of exudate to a desirable limit in canned products. However, crispness, the characteristic quality for a fried fish, was lost during retorting. There was no change in quality characteristics during a storage period of 3 months at ambient temperature (32±2°C).

Lipid breakdown in oil sardine (Sardinella longiceps) during frozen storage

The problem of hydrolysis of lipids and consequent accumulation of free fatty acids and development of rancidity due to oxidation of the lipids are major problems in frozen storage of oil sardine (Sardinella longiceps). The course of the phospholipid breakdown, production of free fatty acids and the changes taking place in the major unsaturated fatty acids during frozen storage are described in this paper. The rate of free fatty acid production is faster in the fish, with the higher fat content. Unlike in lean fish, the neutral lipids are found to contribute substantially to the free fatty acid production. The fatty acids most affected during storage are C sub(20:5) and C sub(22:6). The polyene indices were found to decrease during storage. These effects are more pronounced in the fish with the higher fat content.

Experimental preservation of sardines (Sardinella longiceps), using Chlortetracycline

Effects of dips in 10 and 50 ppm Chlortetracycline solution on the storage-life of sardines in ice have been studied. 5 ppm-CTC-ice in conjunction with dip in 10 ppm CTC-solution has also been tried. CTC-treatment considerably reduced bacterial number and gave a better appearance to the fish. The high fat content in sardines resulted in rapid development of rancidity. CTC has been found to have no control on the development of rancidity. Hence, CTC treatment of sardines is found to be of limited advantage in extending the storage-life of the fish in ice.

Seasonal variation in the chemical composition of pomfret - 2. Silver Pomfret (Pampus argenteus)

Seasonal variation in the proximate composition of different body regions of Pampus argenteus is reported. The fat content of the fish is high during winter whereas during summer the fish becomes lean. A comparison of average values of proximate composition and energy values of silver pomfret and black pomfret (Parastromateus niger) is given.

Formulation, processing and water stability of pelleted feeds with varying levels of protein used in carp nutrition studies

Four dry pelleted feeds containing 20%, 30%, 40% and 45% protein were formulated incorporating casein as the main source of protein for use in carp nutrition studies. The caloric content in all the feeds was maintained constant. The method of processing is described. The formulated diets were tested for water stability. This test has revealed that the diet containing 20%, 30% and 40% protein had better stability than that containing 45% protein. This was due to the relatively higher fat content in the former three diets. However, all the feeds were sufficiently stable at the end of one hour in which time carps are known to utilise supplementary diets.

Studies on freezing and storage of Psenopsis cyanea

The freezing and storage characteristics of Psenopsis cyanea caught on board FORV Sagar Sampada from a depth of 350 m off Cochin are reported. The fat content of the fish was high (15.58% on the weight of whole fish) and the meat was white in colour. Peroxide value, free fatty acids and thiobarbituric acid values increased during frozen storage and organoleptically the fish was acceptable up to 32 weeks at -22 ± 1°C.

Studies on two unexploited fish species: Peristedion adeni and Peristedion weberi

The chemical composition and nutritional quality of Peristedion adeni and Peristedion weberi, two unexploited fish species available in abundance in the Exclusive Economic Zone of India are reported. Size of the fish is small and separation of edible meat is difficult. Best method of utilization of the fish is conversion into meal. Meals having crude protein content varying from 55.0 to 57.0%, ash content from 17.0 to 19.6% and fat content from 17.7 to 18.1% can be prepared from the two species of fish. PER values of the meals are lower than that of casein. Amino acid analysis showed that isoleucine, leucine and valine are not present in the meals in adequate quantities compared to the FAO/WHO (1973) prescribed pattern.

Studies on canning Psenopsis cyanea

Suitability of Psenopsis cyanea, a deep sea fish caught on board FORV Sagar Sampada from a depth of 350m off Cochin for processing into canned product was studied. The fish having high fat content around 52% (DWB) and white attractive meat renders itself well for canning yielding a product good in organoleptic characteristics. However to have a presentable appearance to the product the fish has to be skinned prior to canning. Gentle agitation of P. cyanea in 0.25% aqueous solution of lactic acid at ambient temperature for 15 min followed by thorough washing yields skinless fish. Fish suffers around 8% (DWB) fat loss during skinning. Fish canned in natural style and in brine have better organoleptic characteristics initially. On storage they develop slight rancidity. Fish canned in oil maintains the characteristics over a longer period.

Effect of water washing on biochemical and gel characteristics of minced meat from croaker fish (Johnius gangeticus)

Quality of analog fishery products invariably depends on the gel characteristics and nutritional status of minced meat. With an objective to find out the effect of water washing on kamaboko gel, the minced meat from Croaker fish was washed for four times (5 minutes each) using chilled water at a temperature of 8-10°C. Results reflected noticeable improvement in folding test and SSN% of kamaboko with essential decrease in fat content, water soluble proteins, expressible water and quality parameters like NPN, VBN, TMA, FFA and PV denoting superior gel quality than control sample after repeated washing. The results indicated that there was a definite improvement in functional properties such as gel forming ability, expressible water content of the croaker minced meat essential decrease in fat content, water soluble proteins, expressible water and quality parameters after each wash, but two washes of 5 minutes duration each was necessary to achieve satisfactory results.

Determination of proximate composition, shelf life and fatty acid profiles of breaded kilka (Clupeonella cultriventris) during frozen storage

The present study aimed production of a new product with various texture and sensory properties in chase of the impetus for increasing human consumption considering suitable resources of Kilka fish in Caspian Sea. Following deheading, gutting, and brining, common Kilka were battered in two different formulations, i.e. simple batter and tempura batter, via automated predusting machinery and then, they were fried through flash frying for 30 seconds at 170°C in sunflower oil after they were breaded with bread crumbs flour. The products were subjected to continuous freezing at -40°C and were kept at -18°C in cold storage for four months once they were packed. Chemical composition (protein, fat, moisture, and ash), fatty acid profiles (29 fatty acids), chemical indices of spoilage (peroxide value, thiobarbituric acid, free fatty acids, and volatile nitrogen), and microbial properties (total bacteria count and coliform count) were compared in fresh and breaded Kilka at various times before frying (raw breaded Kilka), after frying (zero-phase), and in various months of frozen storage (phases 1, 2, 3, and 4). Organoleptic properties of breaded Kilka (i.e. odor, taste, texture, crispiness, cohesiveness of batter) and general acceptability in the phases 0, 1, 2, 3, and 4 were evaluated. The results obtained from chemical composition and fatty acid profiles in common Kilka denoted that MUFA, PUFA, and SFA were estimated to be 36.96, 32.85, and 29.12 g / 100g lipid, respectively. Levels of ù-3 and ù-6 were 7.6 and 1.12 g / 100 gr lipid, respectively. Docosahexaonoic acid (20.79%) was the highest fatty acid in PUFA group. ù-3/ù-6 and PUFA/SFA ratios were 7.6 and 1.12, respectively. The high rates of the indices and high percentage of ù-3 fatty acid in common Kilka showed that the fish can be considered as invaluable nutritional and fishery resources and commonsensical consumption of the species may reduce the risk of cardiovascular diseases. Frying breaded Kilka affected overall fat and moisture contents so that moisture content in fried breaded Kilka decreased significantly compared to raw breaded Kilka, while it was absolutely reverse for fat content. Overall fat content in tempura batter treatment was significantly lower than that of simple batter treatment (P≤0.05). Presence of hydrocolloids, namely proteins, starch, gum, and other polysaccharides, in tempura batter may prohibit moisture evaporation and placement with oil during frying process in addition to boosting water holding capacity through confining water molecules. During frying process, fatty acids composition of breaded Kilka with various batters changed so that rates of some fatty acids such as Palmitic acid (C16:0), Stearic acid (C18:0), Oleic acid (C18:1 ù-9cis), and linoleic acid (C18:3 ù-3) increased considerably following frying; however, ù-3/ù-6, PUFA/SFA, and EPA+DHA/C16:0 ratios (Polyan index) decreased significantly after frying. ù-3/ù-6, PUFA/SFA, and EPA+DHA/C16:0 ratios in tempura batter treatment were higher than those of simple batter treatment which is an indicator of higher nutritional value of breaded Kilka with tempura batter. Significant elevations were found in peroxide, thiobarbituric acid, and free fatty acids in fried breaded Kilka samples compared to raw samples which points to fat oxidation during cooking process. Overall microorganism count and coliform count decreased following heating process. Both breaded Kilka samples were of high sanitation quality at zero-phase according to ICMSF Standard. The results acquired from organoleptic evaluation declared that odor, cohesiveness, and general acceptability indices, among others, had significant differences between the treatments (P≤0.05). In all evaluated properties, breaded Kilka with tempura batter in different phases gained higher scores than breaded Kilka with simple batter. During cold storage of various treatments of breaded Kilka, total lipid content, PUFA, MUFA, ù-3, ù- 3/ù-6, PUFA/SFA, Polyen index decreased significantly. The mentioned reductions in addition to significant elevation of spoilage indices, namely peroxide, thiobarbituric acid, and free fatty acids, during frozen storage, indicate to oxidation and enzymatic mechanism activity during frozen storage of breaded Kilka. Considering sensory evaluation at the end of the fourth month and TVB-N contents exceeded eligible rate in the fourth month, shelf life of the products during frozen storage was set to be three months at -18°C. The results obtained from statistical tests indicate to better quality of breaded Kilka processed with tempura batter compared to simple batter in terms of organoleptic evaluation, spoilage indices, and high quality of fat in various sampling phases.