Solar drying and organoleptic characteristics of two tropical African fish species using improved low‐cost solar driers

Abstract

This study was done to evaluate the drying performance, efficiency, and effectiveness of five different types of improved low-cost solar driers in terms of moisture loss from two tropical African fish species Clarias gariepinus (African sharp tooth catfish) and Oreochromis niloticus (Nile tilapia) and testing the organoleptic characteristics of the dried samples. The driers used were made from plastic, aluminum, glass, glass with black igneous stone, and mosquito net, with traditional direct open-sun drying as a control. A significant (P < 0.05) decrease in weight resulting from moisture loss in the two fish species was observed in all the driers, with the highest reduction occurring in the glass drier containing black stone. The rate of weight loss was faster in the first 4 days of drying with black stone-inserted glass drier showing the fastest drying rate with a constant weight in C. gariepinus attained on the 11th day and in O. niloticus on the eighth day. The slowest drier was plastic where a constant weight of the species were recorded on and 13th day and 11th day, respectively. Volunteers were used to assess the organoleptic characteristics of the dried samples and they showed lowest acceptability for the open-sun drying, while samples from the glass drier containing black stone had the highest acceptability in terms of the taste, flavor, appearance, texture, odor, palatability, and shelf-life. The low-cost solar driers were effective found in removing water from the fish resulting in significant loss of weight and moisture. The highest drying time, efficient performance, drying effectiveness, and high acceptability of the organoleptic parameters of the dried products from the black stone-inserted glass drier were due to the ability of the glass and the black stone to retain, transmit, and radiate heat to the fish sample all the time (day and night). These low-cost driers are simple to construct, materials for its construction readily available, easy to maintain and operate, hygienic in use, reliable, effective, occupies less area, dry products faster with increased shelf-life, save man-hour, user-friendly, use renewable energy, protect the drying samples from filthiness, wetness, and invasion by pests, insects, and microbes, with well-dried, high-quality, and better preserved final products. The adoption and use any of these low-cost solar driers by artisanal fishermen and general household in sub-Saharan Africa will not only help in reducing post catch losses, but also ensure food safety and security as there is abundant solar energy in these sub-Saharan African tropical countries for the operation of the driers.

Effect of Different Drying Methods on the Quality Characteristics of Pangasius hypophthalmus

“…Sun drying in open space allows the settling of wind-borne dust, insect and bird infestation and increases inorganic content may be a probable reason for the increase in ash content (Immaculate et al, 2012). The higher ash content was due to the substantial loss of moisture (Mustapha et al, 2014). An increase in ash content was observed in kiln dried and electric oven dried catfish (Clarias gariepinus) from 3.06% to 3.92% and 3.62% (Chukwu and Saha, 2009).…”

“…High ambient temperature prevalent in tropics is responsible for faster spoilage and deterioration of tropical species. Hence quick preservation of fish is important which includes traditional methods like salting or brining, sun drying, solar drying, air drying and smoking in smoking kilns (Mustapha et al, 2014).…”

A Review on Solar Drying of Fish

“…The overall quality of the dried mola fish was excellent as compared with the traditionally dried mola fish, where the color was brown and the texture was soft with off-odor. In general, Mustapha et al (2014) found that the physical parameters of open-sun dried fish was the least acceptable among the fish dried in five other solar driers. Abraha et al (2017) reported that the physical properties, such as color, flavor, appearance, texture and odor was superior for fish dried in a solar tent drier to fish dried in open-sun.…”

“…Using a natural convective solar drier, it was found that the drier was able to reduce the initial moisture content of bayad fish flakes from 78.67% to a final moisture content of 11.41% (Babiker et al, 2014). Mustapha et al (2014) studied five different solar driers and found that black stone-inserted glass drier showed the fastest drying rate in comparison to the plastic drier, mosquito net drier, glass drier and aluminum drier for drying African catfish and Nile tilapia. Martunis (2013) reported that the drying rate of fish using a force convection greenhouse was 3.29% per hour in a total drying time of 11 h while the same amount of fish took 2 days to dry in the sun.…”

Karakteristik Mutu Fisik Tekwan Kering Dengan Rasio Ikan Berbeda

“…Profil pengeringan tekwan pada ketiga rasio ikan dan tapioka menunjukkan adanya 2 periode laju penurunan. Profil pengeringan dengan 2 periode laju penurunan telah dilaporkan pada beberapa pangan segar seperti ikan (Reza et al, 2009;Mustapha et al, 2014), apel (Seiiedlou et al, 2010), dan rumput laut (Gupta et al, 2011).…”