Abstrakt

The study of sorption Isotherms for varied temperatures of Cocoyam

Sunday Iji

The shelf life of materials is an essential attribute to examine since exposure to certain processes and environmental circumstances can cause their physicochemical qualities to deteriorate. As a consequence, the sorption isotherm and physicochemical characteristics of solid cocoyam (size: 95 microns) were investigated in order to determine its appropriateness for use in food systems and storage stability. For varying temperatures and relative humidities, the static gravimetric technique was used.While the sorption isotherm curves produced demonstrated typical type II isotherms, the equilibrium moisture content revealed variations in the quantities of moisture adsorbed. Moisture content, crude protein, fibre, fat, lipid, and ash, as well as carbohydrate content, were all measured chemically. The water absorption capacity, viscosity, and gelatinization temperature were also studied as physical characteristics. After fitting their experimental data with nonlinear regression, the GAB and BET models were shown to adequately represent the data. According to the sorption isotherms study, relative humidity in the range of 65-97 percent would be optimum for storing dry solids in moisture-tight packaging materials. For the BET and GAB models, monolayer moisture content of dried cocoyam varied from 0.018192- 0.028366g/g dry solid and 0.02156-0.028922g/g dry solid, respectively. These figures indicate that storage stability is greater at lower ambient temperatures. According to the findings of this study, cocoyam will last longer when stored at lower temperatures and relative humidity.
The moisture content of stored agricultural goods is generally affected by the environment's temperature and relative humidity. Various biological processes that might result in bio-degradation are supported by equilibrium relative humidity (ERH) or water activity (aw). (Oluwamukomi et al., 2007; Rockland and Nishi, 1980). The impacts of dynamic water flow during crop or crop product storage necessitate close attention for optimal storage characteristics. When harvested, plantain (Musa paradisiacal), a tropical fruit crop, has a high carbohydrate content. Matured fruits have an average moisture content of 61% and ripen quickly after harvest, making long-term preservation in their natural condition problematic (Okunola and Igbeka, 2007). Unripe plantains, on the other hand, are peeled, sun dried, and ground into flour for long-term preservation. Whereas, cocoyam (Cococasia esculenta) is a high-potential root crop commonly produced in Nigeria. It is a good source of calories and is high in starch but poor in protein and oil; and it accounts for a large amount of root crop output in the tropics (F.A.O.1981). When newly picked, it has a high moisture level of around 55%. The crop does not have long-term storage characteristics in its natural condition until it is processed into chips, sun dried, and ground into flour.