三重県内の農場にて通常の品種（アントシアニン濃度水準：高，以下，Hという．）とアントシアニンレスの品種（アントシアニン濃度水準：低，以下，Lという．）を入手した．それぞれの品種を0，3，5 d貯蔵（以下，それぞれ0，3，5という．）に割り付け，貯蔵期間を変えることによりクロロフィル濃度水準を変動させた．すなわち，クロロフィル濃度3水準×アントシアニン濃度2水準の計6種類の試料を用意した（詳細はTable 1の通り）．画像の撮影には，Makino et al.がマンゴー果皮のアントシアニン濃度をコンピュータービジョンで客観的に評価した研究と同一の装置と方法を用いた．
A model to identify the effective diffusivity and to predict the drying kinetics during non-isothermal convective drying of yellow passion fruit (Passiflora edulis Sims f. flavicarpa Degener) seeds was formulated and validated. The governing equations for coupled mass and heat transfer phenomena were expressed in a generalized coordinate system in order to obtain a one-dimensional model suitable for the non-regular geometry of the seeds. Solid shrinkage, moisture and temperature-dependent transport properties, convection heat and mass transfer at the seed surface and symmetrical distribution of moisture content and temperature inside the material were considered. To identify the moisture effective diffusivity, model estimations were fitted to data from drying experiments carried out at air temperatures of 40, 50, and 60℃ and at air velocities of 0.6 and 1.4 m·s−1. The air velocity promoted a lower effect than the air temperature on drying rate, suggesting the internal resistance to mass transfer controlled the water diffusion. The proposed model could contribute to understand the diffusion mechanisms in the material, offering an alternative approach to study the convective drying of non-regular particles due to it requires a simpler solving process and a shorter calculation time than some multidimensional approaches.
The objective of this research was to find the industrially-accepted processing method of the currently underutilized wet grape pomace prior to subsequent extraction of natural ingredients. Due to high moisture content (2.5-3.0 kg/kg db), thermal drying of pomace is an expensive and time-consuming operation. Therefore, the energy efficiency of non-thermal electrohydrodynamic (EHD) technology as applied for grape pomace drying was extensively studied. The experiments on EHD drying at temperature 20℃ revealed excellent quality of the dry product. Superior energy efficiency of the EHD drying ranging from 600 to 1580 kJ per kg of evaporated water as reported in topical literature was confirmed in our experimental study. These preliminary experiments on the lab-scale showed benefits of EHD drying of heat-sensitive grape pomace to be further transformed into food additives, skin powder and grape oil.
Sorption isotherms aid the analysis of different classes of water to determine the energy required to remove this moisture from seeds. The goal of the present study was to determine and analyze the sorption isotherms for barley seeds. Qualitative and quantitative thermodynamic analysis was performed by GAB model parameters and by calculating the net isosteric heat and differential entropy of sorption. The GAB model successfully described the experimental data. The monolayer equilibrium moisture decreased from 0.092 kg·kg-1 to 0.057 kg·kg-1 as the temperature increased from 15 to 50℃. The net isosteric heat of sorption for the monolayer calculated by the GAB equation parameters exhibited good agreement with that calculated by the Clausius-Clapeyron equation, with values of 2433.0 and 2233.7 kJ·kg-1, respectively. Environmental conditions may have affected the formation of the adsorption sites within the seeds endosperm when compared with literature data. The use of empirical models to fit sorption isotherms may mischaracterize the thermodynamic analysis of the monolayer.
The demand to increase food production to feed the growing number of the world population is becoming a primary concern for everyone. At the same time, one-third of the food produced is lost or wasted globally. The food wastes and the by-products of the food production and processing operations still have nutritional ingredients in them suitable for human consumption. To encounter this issue, drying methods can be carried out to add value to food waste, prolong the product’s shelf life and thus provide more food products. Integrated microwave drying systems have the potential to produce dehydrated products from the food waste. In this paper, integrated osmotic dehydration with microwave-assisted hot air drying method is described for the development of dehydrated broccoli stalk product. The techno-economical aspects in terms of raw material availability, process design, energy input, capital inputs, operation costs and environmental benefits are also discussed. This integrated microwave drying concept will be of use to process other biological materials that have the potential at the marketplace.