Geothermal food dehydrator system, operation and sensory analysis, and dehydrated pineapple quality

Abstract

Food dehydration is a preservation technique that guarantees its supply. Food like vegetables and fruits are traditionally dehydrated with natural gas or solar energy, however, this work demonstrates the feasibility of doing it with energy from a geothermal power plant in Nayarit, Mexico. Different species of pineapple (Miel, Cayenne, and Esmeralda) were dehydrated at different temperatures from 64 to 80°C and the safety of the product was subsequently verified, for these aerobic mesophiles (<230 ufc/g), total coliforms (<0.3 s.m.), molds and yeasts (<120 v.e.), and salmonella spp (Absent in 25 g), and results were obtained within the proposed specifications, which were generated taking as reference the national and international guidance standards. A sensory evaluation, a modified Flash Profile (mFP), was carried out with a group of judges trained in descriptive methodology, since a better consensus of responses was obtained, thus demonstrating the usability of mFP for food dehydration. The studies of pineapple allowed the evaluation of production with the DGA 200 technology, and the microbiological standards, as well as sensory and physicochemical parameters, were considering just to verify that product is suitable for human consumption. The technology is a system that takes advantage of the heat of the earth, with which it is possible to work 7 days a week or the entire pineapple season. Physicochemical changes caused by its dehydration with respect to the content of vitamin C, carbohydrates, and dietary fiber in the three species of dehydrated pineapple were measured. In the fresh samples, an average concentration of vitamin C 9 mg/100 g, carbohydrates 11.6 g sugar/100 g, and dietary fiber 0.96% were measured. The dehydrated samples presented an average value of vitamin C of 95 mg/100 g, carbohydrates 72.6 g sugar/100 g, and dietary fiber 8.6%, these results were similar to Mühlbauer and Müller, 2020, Drying atlas, drying kinetics and quality of agricultural products, Elsevier.