Techno-economics of solar assisted drying of small freshwater fish to ensure global nutritional security

Abstract

Small freshwater fishes are a sustainable source of nutrition that is often disregarded in the fishing industry. Even though dry fish sectors utilize these fishes, they often do not reach potential customers due to the time-consuming, weather-dependent traditional drying practices and the associated hygiene-related issues involved in open sun drying of small fishes. There is little to no information on the drying of small freshwater species, especially Vitamin A rich mola carplet. Therefore, the drying behavior and quality characteristics of dried molas were investigated using two available forms of solar conduction dryers – corrugated solar conduction dryer (CSCD) and corrugated electrical solar conduction dryer (CESCD) which were then compared with open sun drying (OSD). The salt and turmeric marinated fresh molas were dried to 1.12%, 4.03%, and 30.82% (d.b.) within 5 h of drying by using CESCD, CSCD, and OSD, respectively and the respective average moisture diffusivity were 12.5 × 10⁻⁹ m²/s, 9.3 × 10⁻⁹ m²/s, and 2.47 × 10⁻⁹ m²/s. The color change (ΔE) kinetics and Vitamin A degradation kinetics were also analyzed for samples dried by using both dryers. The ΔE kinetics showed the color change during drying of mola followed the zero-order kinetics model whereas, Vitamin A degradation followed first-order kinetics. The proximate analysis of key constituents such as proteins and fats showed better retention in CESCD and CSCD as compared to OSD. Economic analysis of both the dryers was used to indicate their commercial feasibility.

Keywords:

• Nutritional security
• solar drying
• vitamin A
• malnutrition
• micronutrients
• quality