Moisture Adsorption Characteristics of Bambara Groundnut (Vigna subterranea) Powders

Rosana G. Moreira, Editor-in-Chief; Texas A&M UniversityThis is a paper from International Commission of Agricultural Engineering (CIGR, Commission Internationale du Genie Rural) E-Journal Volume 9 (2007): Moisture Adsorption Characteristics of Bambara Groundnut (Vigna subterranea) Powders. Manuscript FP 07 005. Vol. IX. November, 2007

Moisture Adsorption Characteristics of Ginger (Zingiber officinale) Powders

The adsorption equilibrium moisture content of the powders of peeled ginger (PGP) and unpeeled ginger (UGP) at 20, 30, 40 and 50 °C were investigated using static gravimetric method. The data were fitted to various sorption models. The thermodynamics of water vapour adsorption of the powders was also investigated at moisture contents in the range of 8 to 20 g H2O/100 g solid. Both powders exhibited the type II isotherms. The equilibrium moisture content of the powder decreased with increasing temperature and increased with water activity. The monolayer moisture content also decreased with an increase in temperature. The powder of peeled ginger was less hygroscopic than that of unpeeled ginger and is therefore more shelf- stable. The GAB, Henderson and Oswin equations accurately fitted experimental sorption data (RMS < 10 %); however, the GAB model gave the best fit. The net isosteric heats (ΔHst) of sorption generally decreased with increasing moisture content. The ΔHst of UGP was generally higher than that of PGP. The isosteric heat of the first molecule (ΔHo) of UGP was also higher (72.042 kJ/mol) than that of the PGP (59.695 kJ/mol). On the other hand, the characteristic moisture content (Mch) of UGP was lower (4.058 g H2O/100g solid) than its equivalent for PGP (4.155 g H2O/100 g solid). The values of ΔHo and Mch indicated the relative low moisture affinity of UGP compared to PGP. The enthalpies of sorption for PGP were lower than UGP. Conversely, the entropy of sorption of UGP was higher (6.233 to 158.180 J/mol-K) than that of PGP (2.496 to 125.721 J/mol-K)

Mass Transfer Considerations in Osmotic Dehydration of Plantain (Musa Paradisiaca) Chips

The influence of process variables and the kinetics of water loss during osmotic dehydration of plantain (Musa paradisiaca) chips in sugar solutions was determined to provide information necessary for further drying and to enable processors maintain its quality. A 3 x 4 factorial in Complete Randomized Design (CRD) experimental design comprising of three sucrose concentrations 29, 33 and 41oBrix and four temperatures 40, 50, 60 and 80oC were used for the study. For each sucrose concentration, plantain slices each 20 g were immersed in sugar solutions contained in 500ml glass beaker which were maintained at 40, 50, 60 and 80oC respectively in agitated water bath while maintaining the syrup to fruit ratio at 5:1 in order to minimize errors arising from changes in syrup concentrations due to mass transfer. Osmotic dehydration kinetics of plantain slices was analyzed based on the models reported by Azoubel and Murr (AMM), and Zungarramudi and Lupin (ZLM). The analysis of variance shows a highly significant syrup concentration, temperature and interaction effect. As the temperature increased, water loss increased and residual water decreased. At all sucrose concentrations studied, water loss was observed to increase with temperature. Results of evaluation of the mass transfer characteristics during osmotic dehydration indicate that both AMM and ZLM gave high regression coefficients ranging from 0.789 to 0.997 for AMM and 0.821 to 0.996 for ZLM. The values of the mean relative deviation modulus (%E) used to evaluate the goodness of fit of the models for AMM and ZLM were generally low, less than 10% indicating that the two models gave good fit to experimental data with ZLM predicting the experimental data better than AMM. The apparent diffusivity (Da) values generally increased with both temperature and sucrose concentration with the values ranging between 3.489x10-12 to 1.857x10-6 m2/s

Effect Of Processing Methods And Storage Environment On Moisture Adsorption Characteristics Of Ginger ( Zingiber Officianale )

The objective of this study was to determine the effect of processing methods and storage parameters on moisture adsorption characteristics of dry matured yellow ginger ( Zingiber officianale ) to provide information for the prediction of shelf life and selection of packaging materials. Moisture adsorption was determined gravimetrically. Saturated solutions of sulphuric acid were prepared to provide constant relative humidity environments. The experimental design was split plot comprising six processing methods (peeled-blanched ginger slice, peeled ginger slice, unpeeled-blanched ginger slice, unpeeled ginger slice, peeled ginger flour and unpeeled ginger flour), four storage temperatures (20, 30, 40 and 50ºC) and six levels of relative humidity in the range of 3.71 - 93.9% which represents some of the environmental conditions that ginger products are exposed to in practice. There was a highly significant processing methods, temperature and water activity effects on the equilibrium moisture content (EMC). For all the processing methods and at all temperature levels, EMC increased with increase in water activity at constant temperature. At constant water activity levels, EMC decreased with increase in temperature. The EMCs of the peeled ginger slices and flours were generally lower than those of the unpeeled ginger at the temperatures and water activities studied. The EMCs of peeled ginger flour were generally higher than the peeled ginger slices at all the temperatures and water activities studied. At any given storage temperature and relative humidity, unpeeled ginger samples were more hygroscopic than the peeled. Also at the temperatures and relative humidities studied, ginger powders absorbed more moisture than the slices. The EMCs of blanched ginger were consistently lower than the unblanched. This implies that blanched ginger has decreased tendency to absorb moisture in storage. Therefore on the basis of shelf stability, Peeled-Blanched Ginger Slice (PBS) is recommended followed by Peeled Ginger Slice (PGS) and Unpeeled-Blanched Ginger Slices (UBS) in that order. The Unpeeled Ginger Slice (UGS), Peeled Ginger Flour (PGF) and Unpeeled Ginger Flour (UGF) did poorly and therefore not recommended

Yam and Moringa oliefera Seed Blend in Lipid Profile Disorders, Kidney and Liver Toxicities, in Alloxan Induced Diabetic Rats

Background and Aim: Diabetes mellitus is a chronic and very prevalent metabolic disease condition characterized by the abnormally high blood sugar level that eventually gives rise to diabetic complications affecting human and animals. Insulin deficiency increases free fatty acid influx and triglyceride levels into the blood, with reciprocal decrease in high-density lipoprotein (HDL) level. Numerous plants have in the past been screened for antidiabetic effects. Plants with medicinal property had served as anti-diabetic In this study; three yam varieties namely Dioscorea alata, Dioscorea cayennessis and Dioscorea rotundata sourced from Wuruku Market, Benue State Nigeria were evaluated for possible anti-diabetic effects. Methods: The collected Moringa seeds were processed into flour. Moringa oleifera seed 45 male albino rats assigned into 9 groups of 5 rats each were used for the study. Eight groups were induced with alloxan monohydrate and were confirmed to be diabetic after two days before treatment with Dioscorea alata control (100%) at 90% + 10% commercial feed, DA90%MRGA10% at (90%) +10% commercial feed, Dioscorea rotundata control (100%) at 90+10% commercial feed, DR90%MRGA10%, at (90%) +10% commercial feed, Dioscorea cayennesis control (100%) at 90% + 10% commercial. DC90%MRGA10% at (90%) +10%commercial feed, Moringa seed meal (100%) at 90% + 10% commercial feed, and 100% commercial feed. Both GRP8 (non-diabetic group) and GRP 9 (diabetic untreated group), were feed with rat Chow only. At the end of 28dys, the rats were sacrificed and the kidney, liver toxicities and lipid profile disorders were all investigated. Results: Result generated showed that diabetes caused liver, kidney toxicity and lipid disorder as evidence in the diabetic untreated groups (GRP9).Groups that received yam/moringa seed meal had significantly decreased (P&lt;0.05) triglycerides (TG), cholesterol (Chol), high density lipoprotein-cholesterol (HDL-C) and VLDL and Serum Liver level of aspartate aminotransferase (AST), alanine aminotransferase (ALT), alkaline phosphatase (ALP), Total protein, Albumin, Creatinine and Urea when compared with diabetic untreated group. Conclusion: A combination of Moringa seed flour and some yam species may be of value in the management of diabetes mellitus and its associated complications