Manual for starch gel electrophoresis: A method for the detection of genetic variation

The procedure to conduct horizontal starch gel electrophoresis on enzymes is described in detail. Areas covered are (I) collection and storage of specimens, (2) preparation of tissues, (3) preparation of a starch gel, (4) application of enzyme extracts to a gel, (5) setting up a gel for electrophoresis, (6) slicing a gel, and (7) staining a gel. Recipes are also included for 47 enzyme stains and 3 selected gel buffers. (PDF file contains 26 pages.)

Effect of modified starch on the shelf life of frozen fish Kamaboko with prepared spinach

Fish kamaboko with spinach was prepared by mixing fish kamaboko with spinach prepared with different combinations of ordinary starch (OS) and modified starch (MS), viz., 40:60, 50:50, 60:40, 100%) MS and 100% OS. The products were frozen at -40°C and stored at -20°C, and subjected to biochemical (peroxide value, total titratable acidity, pH and moisture) organoleptic (appearance, taste and colour), microbiological (total plate count) and physical (folding and expressible water) tests at monthly intervals. Among the different combinations tried, it was observed that fish kamaboko with spinach prepared with 50:50 and 60:40 combinations of OS and MS could be stored for six months at-20°C.

Effects of crude, semipurified and purified starch of sago (Metroxylon sagu Rottb.) on the water stability of pelleted shrimp diets

A study was conducted to determine the comparative effectiveness of purified, semipurified and crude starch of sago as binders for pelleted shrimp diets. The diet containing semipurified sago starch had the highest water stability (79.1%). The values were nearly the same for the pellets bound with purified and crude sago starch. Reasons for the low binding capacity of purified and crude sago could be that the gel of purified sago is weakened due to purification, and that of the crude sago is due to the spongy material present in the product. Thus, semipurified sago starch is a better source of binder and purified crude sago. From the economic viewpoint, the cost of purified sago is prohibitive for use as binder. Both semipurified and crude sago palm starch are acceptable. Composition of shrimp diets containing various sources of sago palm starch, and binder cost and water stability of shrimp diets containing various sources of sago palm starch tested at 3, 6 and 12 hours, are tabulated.

Gum arabic, carrageenan of various types and sago palm starch as binders in prawn diets

An experiment was undertaken in order to investigate the use of sago palm starch, gum arabic and carrageenans as binders in prawn diets. Water stability data are presented; EPT-2 carrageenan was found to be the best binder for both steamed and unsteamed pellets.

Preliminary investigation into implication of a single cell organism in fish feed bouyancy and flotation

Two Isocaloric Isoproteic 30% crude protein diets were formulated for Clariid catfish and Tilapia with wheat grain starch (WGS) and cassava tuber starch (CTS) incorporated at 10 percent as binding agents. Saccharomyces cerevisiae was included at 2% as floating additive. The water stability, nutrient retention and flotation of pelleted feeds were observed for 60 minutes. There were generally decreasing trends in stability and retention at increasing time of immersion in water. The lipid retention was higher (P>0.05) than proteins in both diets. WGS diet was better (P>0.05) than CTS diet in flotation, which has attributed to the presence of gluten protein in wheat products. It is envisaged that a break through in floating feed development in Nigeria aquaculture would save the Nigeria economy from extruded (floating) feed importation

Genetic variation of rougheye rockfish (Sebastes aleutianus) and shortraker rockfish (S. borealis) inferred from allozymes

Rougheye rockfish (Sebastes aleutianus) and shortraker rockfish (Sebastes borealis) were collected from the Washington coast, the Gulf of Alaska, the southern Bering Sea, and the eastern Kamchatka coast of Russia (areas encompassing most of their geographic distribution) for population genetic analyses. Using starch gel electrophoresis, we analyzed 1027 rougheye rockfish and 615 shortraker rockfish for variation at 29 proteincoding loci. No genetic heterogeneity was found among shortraker rockfish throughout the sampled regions, although shortraker in the Aleutian Islands region, captured at deeper depths, were found to be significantly smaller in size than the shortraker caught in shallower waters from Southeast Alaska. Genetic analysis of the rougheye rockfish revealed two evolutionary lineages that exist in sympatry with little or no gene f low between them. When analyzed as two distinct species, neither lineage exhibited heterogeneity among regions. Sebastes aleutianus seems to inhabit waters throughout the Gulf of Alaska and more southern waters, whereas S. sp. cf. aleutianus inhabits waters throughout the Gulf of Alaska, Aleutian Islands, and Asia. The distribution of the two rougheye rockfish lineages may be related to depth where they are sympatric. The paler color morph, S. aleutianus, is found more abundantly in shallower waters and the darker color morph, Sebastes sp. cf. aleutianus, inhabits deeper waters. Sebastes sp. cf. aleutianus, also exhibited a significantly higher prevalence of two parasites, N. robusta and T. trituba, than did Sebastes aleutianus, in the 2001 samples, indicating a possible difference in habitat and (or) resource use between the two lineages.

Genetic analysis of juvenile coho salmon (Oncorhynchus kisutch) off Oregon and Washington reveals few Columbia River wild fish

Little is known about the ocean distributions of wild juvenile coho salmon off the Oregon-Washington coast. In this study we report tag recoveries and genetic mixed-stock estimates of juvenile fish caught in coastal waters near the Columbia River plume. To support the genetic estimates, we report an allozyme-frequency baseline for 89 wild and hatchery-reared coho salmon spawning populations, extending from northern California to southern British Columbia. The products of 59 allozyme-encoding loci were examined with starch-gel electrophoresis. Of these, 56 loci were polymorphic, and 29 loci had P0.95 levels of polymorphism. Average heterozygosities within populations ranged from 0.021 to 0.046 and averaged 0.033. Multidimensional scaling of chord genetic distances between samples resolved nine regional groups that were sufficiently distinct for genetic mixed-stock analysis. About 2.9% of the total gene diversity was due to differences among populations within these regions, and 2.6% was due to differences among the nine regions. This allele-frequency data base was used to estimate the stock proportions of 730 juvenile coho salmon in offshore samples collected from central Oregon to northern Washington in June and September-October 1998−2000. Genetic mixed-stock analysis, together with recoveries of tagged or fin-clipped fish, indicates that about one half of the juveniles came from Columbia River hatcheries. Only 22% of the ocean-caught juveniles were wild fish, originating largely from coastal Oregon and Washington rivers (about 20%). Unlike previous studies of tagged juveniles, both tag recoveries and genetic estimates indicate the presence of fish from British Columbia and Puget Sound in southern waters. The most salient feature of genetic mixed stock estimates was the paucity of wild juveniles from natural populations in the Columbia River Basin. This result reflects the large decrease in the abundances of these populations in the last few decades.

Utilisation of trash fish. Pt. 1. Preparation of fish flake

The paper deals with the investigations carried out on the preparation of odorless fish-starch flakes using partially deodorized trash fish meat and different sources of starch like corn, tapioca, maida and black gram. It has been found that the products using corn and tapioca are better compared to those prepared using other two starches, the product from corn being the best. The product has a protein content of about 20% and has been found to have a storage life of 4 months at 37°c.

Surimi based dried fish cake

Minced fish prepared from the fillets of the sciaenid fish (Lutjanus sp.) was washed with cold water (<10 °C) three times. The washed muscle was pressed through a piece of fine cloth to a moisture content around 80%. The pressed cake (Surimi) was ground with 2.5% sodium chloride and 3% tapioca starch. The mixed material was shaped in the form of a cake and left for one hour for the gel to set. The cakes were then steamed. The cooled cakes were cut into pieces of 1 cm length x 1 cm width x 0.5 cm thick. The pieces were either dried in an electrical oven at 50°C or dried in sun to a moisture content of 11-12%. Biochemical, bacteriological and organoleptic evaluation revealed that the cakes were in very good acceptable form for 8 months. The cakes could be rehydrated by soaking in water at ambient temperature for half an hour and boiling in water for 10 minutes.

Dried fish cakes with improved texture

To overcome the problem of underutilization of marine by-catches, Basu et al. (1985) developed fish cube from minced fish meat. Although the product was acceptable, it had little rubbery texture. An attempt was made to improve the texture of the cake by several methods. It was found that 5% tapioca starch along with 3% texturised soybean protein improved the texture and juiciness of the rehydrated product. Preheating of the minced meat at 70°C for 30 minutes also improved the texture appreciably. It was also found that mixing of the ingredients at low speed (less than 100 rpm) in a dough mixer gave the best texture, higher speed and sharp blades leading to rubbery texture. The dehydrated product (moisture 19-20%) thus prepared had a shelf life of six months at ambient temperature.

Studies on the suitability of producing value-added products from silver carp, Hypophthalmichthys molitrix

Silver carp, Hypophthalmichthys molitrix is contributing significantly to the total production of fish through aquaculture in Bangladesh. However, its low market price has become a serious concern to the fish farmers. The suitability of silver carp mince for the production of various value-added products (VAPs) - surimi, fish sausage, fish burger and fish stick was studied during April-September 2000 to ensure more appropriate and profitable utilization of silver carp. Surimi/frozen mince block was produced by washing the silver carp mince with 0.1% NaCl for 7-8 min (4-5 min agitation and 3-4 min settling). A two-step heating schedule for incubation at 50°C for 2 h and cooking at 95°C for 30 min gave high textured good quality consumer product. With the addition of cryoprotectants, surimi could be kept frozen for 5 months without loosing [sic] much of its textural and sensory qualities. Mince-mix and a batter with different ingredients and spices were formulated to produce fish burger using potato smash as the binding agent. Fish flake-mix and a batter with different ingredients and spices were formulated to prepare fish stick using both potato starch and potato smash as filler ingredients. Unwashed and washed frozen mince block or fresh flesh of silver carp was used to prepare fish sausage by heating at 100°C for 1 h after incubating at 50°C for 2 h. A spice-mix formulated with various local spices at the rate of 1.0-1.2% gave good texture and flavor to the sausage. A good-appeared sausage-pink color was developed by combining three food-grade colors of asthaxanthin. Products prepared with potato starch, potato smash and rice smash had an acceptable bacterial load in refrigeration (5°C) for up to 8 days and in room temperature (28°C) for up to 3 days. No coliform bacteria were found in the products prepared.

Sequential analysis for testing quality standard of fish ham and sausage

Fish sausages are finely ground fish flesh, either of a single species or mixed, homogenised with starch, sugar, fat, spices and preservatives, generally filled in cylindrical synthetic or natural casings and pasteurised. Similar products containing small pieces of quality fish and lard are termed "fish ham". They are highly relished products in Japan, annual consumption exceeding 2 lakh tones. Preliminary studies have shown that they can catch a lucrative market in our country. However, being a pasteurised product which is often consumed as such without any further cooking, strict quality control measures have to be enforced so as to avoid food poisoning hazards. Besides physical characteristics like absence of damages, pin-holes, curliness and air pockets as well as jelly strength, texture and flavour, chemical characteristics like pH and acid values, moisture, carbohydrate and fat contents and volatile bases have to be assessed. A very important test that has to be carried out along with the above, before passing a lot for free distribution is the bacteriological examination to avoid the presence of pathogenic organisms.

Purification and characterisation of phosphorylase from muscle of Tilapia (Tilapia mosambica)

Phosphorylase from muscle of tilapia (Tilapia mosambica) was extracted by water and purified by ammonium sulphate precipitation, centrifugation and repeated recrystallisation. Electro-phorogram of the enzyme preparation showed a single band near origin. The enzyme showed optimum pH and temperature at 6.1 and 37°C respectively. Glucose and glucose-6-phosphate were found to be competitive inhibitors of the enzyme. Maltose and starch acted as primers for the phosphorylase reaction like glycogen.

Preliminary chemical and physical evaluation of some formulated feeds for P. monodon

The culture of Penaeus monodon has explicitly defined the need for diet formulations or supplementary feeds that would promote optimum growth and survival of the animal. A total of 28 feed combinations were developed for P. monodon. Fish meal, shrimp head meal, squid head meal, Ascetes spp. rice bran, and soybean cake were used as primary ingredients in these feeds. The commercial vitamin mix No. 22 was added to the dry ingredients. Gelatinized corn starch and wheat flour were used as binders. The pellets were extruded using a portable kitchen grinder with a diameter of 4 mm. The products were either sun-dried for 8 hours or oven-dried overnight at 50 degree C to stabilize moisture at 8-10%. The pellets were then kept in covered glass bottles and stored in the laboratory at room temperature. The cost of the feeds excluding labour were also computed. The pellets were analyzed for protein, fat, carbohydrate, crude fiber, ash, and moisture contents using standard procedures. They were also analyzed for water stability. To test the stability of pellets in water, 2-g samples were placed in plankton nets (mesh #40) and suspended in water for two, and six hours. The undissolved samples were then vacuum-dried and the moisture determined. Cost of the feeds ranged from P1.10 to P2.60 per kg depending on the feed ingredient. Squid and Ascetes spp. were rather expensive for use as basic ingredients. Proximate analysis of dry weight showed percentage protein content ranged from 20-63 g; fat, 8-20 g; carbohydrate (by difference), 11-36 g; ash, 8-28 g; moisture, 6-11 g; and crude fiber, 5 . 13 g. Stability tests showed that after two hours, 35-88% of solids remained intact and after 6 hours, 20-55% of the pellets remained undissolved. When a pellet disintegrates easily, pollution of the water occurs. Chances for the shrimp to feed on the pellet is minimized when the pellet is unstable. Thus, the search for a more compact feed pellet has to be continued.

The effect of different binders on the water stability of feeds for prawn

Corn starch, gelatin, sago palm starch, agar, and bread flour were tested for their binding capacity in pelleted diets for Penaeus monodon . Agar was found to be good binder, but it costs too much, while bread flour was also good but as it's commonly used for human comsumption its use for animal feed should be minimized. The use of 20% bread flour, or a combination of 5% sago palm starch or corn starch with 15% bread flour is recommended, depending on the cost and availability. Basic composition of the formulated diet is tabulated, as is water stability of 2 and 4 mm diameter steamed pellets after 2, 6 and 18 h.