The effect of traditional handling, processing and storage methods on the quality of dried fish in small scale fisheries in Nigeria

Most of the fish marketed throughout Nigeria are in either smoked or dried form. The technological requirement for other forms of preservation like chilling and freezing cannot be afforded by the small scale fisher folk. Considerable quantities of fish processed for distant consumer markets are lost at handling, processing, storage and marketing stages. Significant losses occur through infestation by mites, insects, fungal infestation and fragmentation during transportation. This paper attempts to describe the effect of these losses on fish quality and suggests methods of protecting fish from agents of deterioratio

Study of the solar dried and traditional sun-dried fish products

Drying of freshly caught fish to heat from sunlight is the simplest method of fish preservation in the arid regions of the tropics, where heat energy from sunlight is of considerable intensity, the Kainji Solar Tent Dryer was developed to improve the traditional drying methods Bagrus bajad was used in this study as a result of its dominance in the Jebba and Kainji Lake Basin. The fish were dried in the Kainji Solar Tent Dryer and open sun and dying was completed within 2-4 days. Results from organoleptic study show that dried fish products in the Kainji Solar Tent Dryer were light, whitish-yellow colour, while the sun dried fish was dark orange in colour. Solar dried fish had mean score of 8.2 for appearance while sun dried fish had 5.2, sun dried fish had 6.6 for texture while solar dried fish had 7.8. For odor and taste solar dried fish had mean score of 8.2 and 8.4 while sun dried fish had 4.6 and 0. Moisture content was 10.6 for solar dried fish compared to 22.26 for sun dried fish. Crude protein and fat were 62.3 and 16.25 for sun dried fish compared to 82.14 and 8.46 for solar dried fish. Solar dried fish had 43.3cfu/gm compared to 132 cfu/gm for sun dried fish in the microbiological load assessment. Organoleptic assessment of the final dried product showed that the solar-dried fish were of better fish quality than traditional sun-dried fish

Effects of wood type on the nutrient composition of smoked-dried Citharinus citharus

The effect of wood types on the nutrient composition of smoked dried fish was carried out using Citharinus citharus. The wood types used for the experiment were Neem, Parkia and Terminalia. The fish samples were smoked dried to constant weight under the same conditions using the three wood types. Proximate nutrient composition of the fish samples and phytochemical analysis of the wood types was determined. Sensory evaluation on the organoleptic properties of the smoked fish samples was also conducted using a test panel to determine the general acceptability of the fish products in relation to the wood type used. Result of the proximate nutrient composition showed that fish sample smoked dried with Terminalia had the highest percentage of protein followed by that of Parkia. Fat content was highest in the fish sample smoked dried with Neem tree. The result of the phytochemical analysis of the wood types revealed the presence of high levels of tannin in Neem, tannins and phenolic compounds in Parkia. Organoleptic evaluation of the products showed that the fish samples smoked dried with Terminalia had the highest general acceptability

Enzymatic hydrolysis of fish frames using pilot plant scale systems

Papain was used to hydrolyse fish frames under controlled conditions at a batch-pilot plant scale-process, for the pro-duction of fish protein hydrolysates (FPH). Mass balance calculations were carried out so that the rate of hydrolysis, rate of protein solubilisation and yields could be estimated. Almost complete hydrolysis could be achieved in 1 hour, at 40°C, with no pH adjustment, at 0.5% (5 g·kg−1) enzyme to substrate ratio (E/S, were S is Kjeldahl protein) using whole fish frames (including heads and flaps). This was achieved both with the addition of water (1/1 to 2/1 frames/water) but more importantly from commercial considerations without the initial addition of water (after mincing of the fish mate-rial). The degree of protein solubilisation ranged between 71% - 86% w/w. Four different processes are described, namely: 1) a soluble spray-dried FPH powder; 2) a liquid FPH; 3) a partly soluble, spray dried FPH powder and; 4) a crude, drum-dried protein for animal consumption. The amino acid profile of the FPH was identical to that of the par-ent substrate (fish frames)

A survey of the quality of salt cured fish produced in the Kanyakumari Disrict [i.e. District], Madras State

A survey of the quality of salt cured fish in Kanyakumari District, Madras State was done during the years 1963 and 1964 to obtain necessary basic information to formulate quality standards for these products which are gaining importance in the export trade. 155 trade samples of sun-dried, dry-salted, wet-cured and pit-cured fishery products were examined for their chemical quality and organoleptic characteristics. 26.5% of the sun-dried products, 25% of the wet cured fish, 55.21% of the dried salted products and none of the pit cured samples were found to be good in quality. The sun dried products were generally found to have heavy admixture of sand and were inadequately dried. The chief defects in the salt cured fish products were found to be the use of spoiled fish, imperfect cleaning and washing, use of impure salt, inadequate salting, curing and drying, and unhygienic conditions in all stages. Quality standards must be formulated for each variety of salt cured fish product and adequate measures taken to rectify the defects and enforce the quality standards

Proximate composition of Pseudotolithus elongatus subjected to different processing techniques

The changes that occur on proximate composition of some common fish processing methods used in Nigeria were studied in order to determine the nutritional content of the processed products. Traditional (smoke drying and sun drying) and modern (electrical oven drying) methods of processing were used to process Pseudotholithus elongatus and the results were compared with the fresh sample to determine the changes that occur during processing. The results for the fresh sample of P. elongatus were 79.50%, 1.50%, 0.8% and 18.2% for moisture, ash, lipid and protein. For the processed products, the moisture content for smoke-dried, sun-dried, salt sun-dried and oven-dried fish were 27.00%, 21.83%, 19.50% and 20.17% . Oven dried had the highest protein content (69.87%) while salt sun-dried had the lowest (54.90%). Lipid content was highest in sun-dried (6.6%) and lowest in smoke-dried (4.6%). Correlation between smoke-dried and sun-dried were r2 = 0.99, smoke-dried and oven-dried were r2= 0.98 and smoke-dried and salt sun-dried were r2= 0.98. There was no correlation between the fresh and the processed P.elongatus. The present findings revealed that processing affect the nutritional composition of fish

Incidence of arthropods in dried fish products

Arthropods have been recorded from various types of insect infested dried fish products stored in the laboratory. They have been identified as Suidesia nesbetti Hughes (Acaridae) infesting dried anchovies and dried mussel, Dermestes ater Dermestidae coleoptera) attacking wet cured sardines and smoked catfish and Stegobium panicium infesting smoked catfish and dried mussel. Incidences of Stegobium panicium in dry fish products and Suidesia nesbetti in dried mussel has been recorded for the first time