Effect of Different Drying Methods on Drying Characteristics, Colour and Microstructure Properties of Barbunia Bean (Phaseolus vulgaris L.)

In this study, the effects of microwave, convective, and microwave-convective drying treatments on the drying parameters, colour and microstructure properties of barbunia samples were investigated. To select the best thin-layer drying models for the drying treatments, 9 mathematical models were fitted to the experimental data and the performances of these models were compared for the following statistical parameters: reduced chi-squared (χ2), root mean square error (RMSE) and coefficient of determination (R2). Among the drying models investigated, the Midilli et al. model was found to be the best model for describing the drying behaviour of barbunia beans. The experimental results showed that increasing the drying temperature or microwave power level caused shorter drying time and the combined microwave-convective method provided the greatest time savings in comparison to other methods tested. At all drying conditions, the closest values to the colour of fresh barbunia was obtained at 50C. It was found that browning increased with an increase in drying temperature and microwave power. Scanning electron microscopy images revealed that the applications of all the drying methods led to different physical changes in the products’ microstructures when compared to fresh samples.

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  • Agrawal YC and Singh RP (1977). Thin-layer drying studies on short-grain rice. ASAE Paper No. 77–3531, St. Joseph, MI, USA.
  • Akpinar EK (2006). Determination of suitable thin layer drying curve model for some vegetables and fruits. Journal of Food Engineering, 73: 75–84.
  • Ayensu A (1997). Dehydration of food crops using a solar dryer with convective heat flow. Solar Energy, 59: 121–126.
  • Bondaruk J, Markowski M and Błaszczak W (2007). Effect of drying conditions on the quality of vacuum-microwave dried potato cubes. Journal of Food Engineering, 81: 306–312.
  • Cetin M (2007). Physical properties of barbunia bean (Phaseolus vulgaris L. cv. ‘Barbunia’) seed. Journal of Food Engineering, 80: 353–358.
  • Cheng WM, Raghavan GSV, Ngadi M and Wang N (2006). Microwave power control strategies on the drying process II. Phase-controlled and cycle-controlled microwave/air drying. Journal of Food Engineering, 76: 195–201.
  • Contreras C, Martin-Esparza ME, Chiralt A and Martinez-Navarrete N (2008). Influence of microwave application on convective drying: Effects on drying kinetics, and optical and mechanical properties of apple and strawberry. Journal of Food Engineering, 88(1): 55–64.
  • Doymaz I (2006). Thin-layer drying behaviour of mint leaves. Journal of Food Engineering, 74: 370–375.
  • Ertekin C and Yaldiz O (2004). Drying of eggplant and selection of a suitable thin layer drying model. Journal of Food Engineering, 63: 349–359.
  • Funebo T and Ohlsson T (1998). Microwave-assisted air dehydration of apple and mushroom. Journal of Food Engineering, 3: 353–367.
  • Giri SK and Prasad S (2007). Drying kinetics and rehydration characteristics of microwave-vacuum and convective hot-air dried mushrooms. Journal of Food Engineering, 78: 512–521. Gowen AA, Abu-Ghannam N, Frias J and Oliveira J (2008). Modeling dehydration and rehydration of cooked soybeans subjected to combined microwave-hot-air drying. Innovative Food Science & Emerging Technologies, 9: 129–137.
  • Goyal RK, Kingsly ARP, Manikantan MR and Ilyas SM (2006). Thin-layer drying kinetics of raw mango slices. Biosystems Engineering, 95: 43–49.
  • Isik E and Unal H (2007). Moisture-dependent physical properties of white speckled red kidney bean grains. Journal of Food Engineering, 82: 209–216.
  • Izli N and Isik E (2014). Effect of different drying methods on drying characteristics, colour and microstructure properties of mushroom. Journal of Food and Nutrition Research, 53(2): 105-116.
  • Karaaslan SN and Tuncer IK (2008). Development of a drying model for combined microwave-fan-assisted convection drying of spinach. Biosystems Engineering, 100: 44–52.
  • Kassem AS (1998). Comparative studies on thin layer drying models for wheat. In: 13th International Congress on Agricultural Engineering, Vol. 6, Morocco.
  • Kayisoglu S and Ertekin C (2011). Vacuum drying kinetics of barbunya bean (Phaseolus vulgaris L. elipticus Mart.). The Philippine Agricultural Scientist, 94: 285–291.
  • Kose B and Erenturk S (2010). Drying characteristics of mistletoe (Viscum album L.) in convective and UV combined convective type dryers. Industrial Crops and Products, 32: 394–399. Madamba PS, Driscoll RH and Buckle KA (1996). The thin-layer drying characteristics of garlic slices. Journal of Food Engineering, 29: 75–97.
  • Maskan M (2000). Microwave/air and microwave finish drying of banana. Journal of Food Engineering, 44: 71–78.
  • Maskan M (2001). Kinetics of colour change of kiwifruits during hot air and microwave drying. Journal of Food Engineering, 48: 169–175.
  • McMinn WAM (2006). Thin-layer modeling of the convective, microwave, microwave-convective and microwave-vacuum drying of lactose powder. Journal of Food Engineering, 72: 113–123.
  • Midilli A, Kucuk H and Yapar Z (2002). A new model for single layer drying. Drying Technology, 20: 1503–1513.